Mobile Assignment I

MOBILE COMPUTING ASSIGNMENT NO 1

Q1 Is a directional antenna useful for mobile phones Why How can the gain of antenna be improved

Ans Antennas couple electromagnetic energy to and from space

to and from a wire or coaxial cable (or any other appropriate conductor)

A theoretical reference antenna is the isotropic radiator a point in space

radiating equal power in all directions ie all points with equal power are

located on a sphere with the antenna as its center The radiation pattern is

symmetric in all directions

However such an antenna does not exist in reality Real antennas all

exhibit directive effects ie the intensity of radiation is not the same in all

directions from the antenna The simplest real antenna is a thin center-fed

dipole also called Hertzian dipole

The dipole consists of two collinear conductors of equal length separated by a small feeding gap The length of the dipole is not arbitrary but for example half the wavelength λ of the signal to transmit results in a very efficient radiation of the

energy If mounted on the roof of a car the length of λ4 is efficient This is also known as Marconi antenna

A λ2 dipole has a uniform or omni-directional radiation pattern in one plane and a figure eight pattern in the other two planes This type of antenna can only overcome environmental challenges by boosting the power level of the signal Challenges could be mountains valleys buildings etc

Q2 What are the main problems of signal propagation Why do radio waves not always follow a straight line Why is reflection both useful amp harmful

Ans

In wireless networks the signal has no wire to determine the direction of propagation whereas signals in wired networks only travel along the wire (which can be twisted pair copper wires a coax cable but also a fiber etc) As long as the wire is not interrupted or damaged it typically exhibits the same characteristics at each point One can precisely determine the behavior of a signal travelling along

this wire eg received power depending on the length For wireless transmission this predictable behavior is only valid in a vacuum ie without matter between the sender and the receiver

Transmission range Within a certain radius of the sender transmission is possible ie a receiver receives the signals with an error rate low enough to be able to communicate and can also act as sender

Detection range Within a second radius detection of the transmission is possible ie the transmitted power is large enough to differ from background noise However the error rate is too high to establish communication

Interference range Within a third even larger radius the sender may interfere with other transmission by adding to the background noise A receiver will not be able to detect the signals but the signals may disturb other signals

Radio signal propagation faces the following problems

bull Attenuation (amplitude of the wave loses strength thereby the signal power)bull Refractionbull Reflectionbull Shadowingbull Scatteringbull Diffraction

Radio waves do not follow a straight line because of blocking objects in its path

Reflection is useful because in non-line-of-sight environments (where there is no direct path from the transmitter to receiver for example in offices town and cities) it allows the radio signal to reach from the transmitter to the receiver Reflection can be harmful because multiple copies of the same signal can reach the receiver at different times

Q3 What are the main reasons for using cellular systems How is SDM typically realized and combined with FDM How does DCA influnence the frequencies available in other cells

Answer -Cellular systems for mobile communications implement SDM Each transmittertypically called a base station covers a certain area a cell Cell radii can varyfrom tens of meters in buildings and hundreds of meters in cities up to tens ofkilometers in the countryside The shape of cells are never perfect circles orhexagons but depend on the environment (buildings mountains valleys etc) on weather conditions and sometimes even on system load Typical systems using this approach are mobile telecommunication systems where a mobile station

within the cell around a base station communicates with this base station and vice versa

Advantages of cellular systems with small cells are the following Higher capacity Implementing SDM allows frequency reuse If one transmitteris far away from another ie outside the interference range it can reuse the same frequencies As most mobile phone systems assign frequencies to certain users (or certain hopping patterns) this frequency is blocked for other users But frequencies are a scarce resource and the number of concurrent users per cell is very limited Huge cells do not allow for more users On the contrary they are limited to less possible users per km2 This is also the reason for using very small cells in cities where many more people use mobile phones Less transmission power While power aspects are not a big problem for base stations they are indeed problematic for mobile stations A receiver far away from a base station would need much more transmit power than the current few Watts But energy is a serious problem for mobile handheld devices Local interference only Having long distances between sender and receiver results in even more interference problems With small cells mobile stations and base stations only have to deal with lsquolocalrsquo interference Robustness Cellular systems are decentralized and so more robust against the failure of single components If one antenna fails this only influences communication within a small area

Small cells also have some disadvantages Infrastructure needed Cellular systems need a complex infrastructure to connect all base stations This includes many antennas switches for call forwarding location registers to find a mobile station etc which makes the whole system quite expensive

Handover needed The mobile station has to perform a handover when changing from one cell to another Depending on the cell size and the speed of movement this can happen quite oftenFrequency planning To avoid interference between transmitters using the same frequencies frequencies have to be distributed carefully On the one hand interference should be avoided on the other only a limited number of frequencies is available

Higher capacity higher number of the users cellular systems can reuse spectrum according to certain patterns Each cell can support a maximum number of users Support user localisation and location based services Less transmission power needed Smaller cells also allow for less transmission power ( thus less radiation) The mobile systems can enjoy longer runtimeTypically each cell holds a certain number of frequency bands Neighboring cells are not allowed to use the samefrequencies

Whether or not DCA depends on the current load It can react upon sudden increase in traffic by borrowing capacity from other cells However the rdquoborrowedrdquo frequency must then be blocked in neighboring cells

Q4 What limits the number of simultaneous users in a TDMFDM system compared to a CDM systemWhat happens to the transmission quality of connections if the load gets higher in a cell ie how does an additional user influence the other users in the cell for both TDMFDM and CDM systems

Ans FDMTDM system have a hard upper limit of simultaneous users The system assigns a certain time-slot at a certain frequency to a user If all time-slots at all frequencies are occupied no more users can be accepted Compared to this rdquohard capacityrdquo a CDM system has a so-called rdquosoft-capacityrdquo The signal-to-noise-ratio typically limits the number of simultaneous users

The system can always accept an additional user However the noise level may then increase above a certain threshold where transmission is impossible In TDMFDM systems additional users if accepted do not influence other users as users are separated in time and frequency( well there is some interference howeverthis can be neglected in this context)

In CDM systems each additional user decreases transmission quality of all other users

Q5 Recall the problem of hidden and exposed terminals What is the effect of such terminals if Aloha slotted Aloha reservation Aloha or MACA is used

Ans

bull In Aloha hidden station is a serious problem Stations start sending their data and because of runtime to the satellite it needs long time till the satellite has repeated the information and sent it down to all stations Thus there can be lots of hidden stations we will learn about only very late On the other hand exposed

stations donrsquot exist ndash a potential sender does not listen to the medium before sending thus he cannot be exposed

bull For Slotted Aloha it is the same as for traditional Aloha

bull For Reservation-Aloha both problems donrsquot exist Because we work with reservations all other stations know about ours at well at their own sending times Only in the reservation phase we can have problems with placing reservations but because we will recognize if someone else tried to do the same reservation as we the other stations are not really hidden to us

bull MACA was designed to avoid both hidden and exposed stations (Note exposed stations in principle are avoided because a station which can hear the RTS but not the CTS could interpret it as not influencing the receiver But in reality also a station which cannot hear the CTS but hears a transmission begin after an RTS has to wait because each sender also becomes a receiver ndash even if only for an ACK after finishing its transmission) Nevertheless if we have changing topology (ie mobile devices) or asymmetric connections a station can miss the RTSCTS messages and send without knowing that something is destroyed

Q 6 Explain the term interference in the space time frequency and code domain What are countermeasures in SDMA TDMA FDMA and CDMA systems

Ans Interference and countermeasures are

bull SDMA Interference is overlapping of cells Just leave a protective distance between base stations andor devices

bull TDMA Interference is simultaneous transmission of several stations Synchronization and time gaps between time slots are countermeasures

bull FDMA Interference means transmission on the same carrier frequency Countermeasures are protective gaps on the frequency band

bull CDMA Interference is sending with correlated codes Thus orthogonal or quasiorthogonal codes have to be used (ie the gap in this example is in code orthogonality)

Q 7What is the main physical reason for the failure of many MAC schemes known from wired networks What is done in wired networks to avoid this effect

Ans Stations in a wired network ldquohearrdquo each other Ie the length of wires is limited in a way that attenuation is not strong enough to cancel the signal Thus if one station transmits a signal all other stations connected to the wire receive the signal The best example for this is the classical Ethernet 10Base2 which has a bus topology and uses CSMACD as access scheme Todayrsquos wired networks are star shaped in the local area and many direct connections forming a mesh in wide area networks In wireless networks it is quite often the case that stations are able to communicate with a central station but not with each other This lead in the early seventies to the Aloha access scheme (University of Hawaii) So what is CS (Carrier Sense) good for in wireless networks The problem is that collisions of data packets cause problems at the receiver ndash but carrier sensing takes place at the sender In wired networks this doesnrsquot really matter as signal strength is almost the same (ok within certain limits) all along the wire In wireless networks CS and CD at the sender doesnrsquot make sense senders will quite often not hear other stationsrsquo signals or the collisions at the receiver

Q9 Describe the functions of the MS and SIM Why does GSM sperate the MS amp SIM How amp where is User-related data representedstored in the GSM system

Ans

Mobile station (MS) The MS comprises all user equipment and softwareneeded for communication with a GSM network An MS consists of user independent

hard- and software and of the subscriber identity module(SIM) which stores all user-specific data that is relevant to GSM3 While and MS can be identified via the international mobile equipment identity (IMEI) a user can personalize any MS using his or her SIM ie user-specific mechanisms like charging and authentication are based on the SIM not on the device itself Device-specific mechanisms eg theft protection use the device specific IMEI Without the SIM only emergency calls are possible The SIM card contains many identifiers and tables such as card-type serial number a list of subscribed services a personal identity number (PIN)

PIN unblocking key (PUK) an authentication key Ki and the internationalmobile subscriber identity (IMSI) (ETSI 1991c) The PIN is used to unlock the MS Using the wrong PIN three times will lock the SIM In suchcases the PUK is needed to unlock the SIM The MS stores dynamic information

while logged onto the GSM system such as eg the cipher key Kc andthe location information consisting of a temporary mobile subscriber identity(TMSI) and the location area identification (LAI) Typical MSs for GSM 900 have a transmit power of up to 2 W whereas for GSM 1800 1 W isenough due to the smaller cell size Apart from the telephone interface an3 Many additional items can be stored on the mobile device However this is irrelevant to GSMMS can also offer other types of interfaces to users with display loudspeakermicrophone and programmable soft keys Further interfaces comprise computermodems IrDA or Bluetooth Typical MSs eg mobile phonescomprise many more vendor-specific functions and components such ascameras fingerprint sensors calendars address books games and Internet browsers Personal digital assistants (PDA) with mobile phone functions are also available The reader should be aware that an MS could also be integrated into a car or be used for location tracking of a container

Q10 How is user data protected from unautheraised accessespecially over the air interface How could the position of an MS be localised Think of the MS reports regarding signal quality

Ans Authentication centre (AuC) As the radio interface and mobile stations are particularly vulnerable a separate AuC has been defined to protect user identity and data transmission The AuC contains the algorithms for authentication as well as the keys for encryption and generates the values needed for user authentication in the HLR The AuC may in fact be situated in a special protected part of the HLR

Equipment identity register (EIR) The EIR is a database for all IMEIs ie it stores all device identifications registered for this network As MSs are mobile they can be easily stolen With a valid SIM anyone could use the stolen MS The EIR has a blacklist of stolen (or locked) devices In theory an MS is useless as soon as the owner has reported a theft Unfortunately the blacklists of different providers are not usually synchronized and the illegal use of a device in another operatorrsquos network is possible (the reader may speculate as to why this is the case) The EIR also contains a list of valid IMEIs (white list) and a list of malfunctioning devices (gray list)

Security GSM offers several security services using confidential information stored in the AuC and in the individual SIM (which is plugged into an arbitrary MS) The SIM stores personal secret data and is protected with a PIN against unauthorized use (For example the secret key Ki used for authentication and encryption procedures is stored in the SIM) The security services offered by GSM are explained below

Access control and authentication The first step includes the authentication of a valid user for the SIM The user needs a secret PIN to access the SIMThe next step is the subscriber authentication (see Figure 410) This step is based on a challenge-response scheme as presented in section 4171

Confidentiality All user-related data is encrypted After authentication BTS and MS apply encryption to voice data and signaling as shown in section 4172 This confidentiality exists only between MS and BTS but it does not exist end-to-end or within the whole fixed GSMtelephone network

Anonymity To provide user anonymity all data is encrypted before transmission and user identifiers (which would reveal an identity) are not used

over the air Instead GSM transmits a temporary identifier (TMSI) which is newly assigned by the VLR after each location update Additionally the VLR can change the TMSI at any time Three algorithms have been specified to provide security services in GSM

Q11 How is localisation location updateroamingetc done in GSM amp reflected in the database What are typical roaming scenarios List the enities of mobile IP amp describe data transfer from mobile node to a fixed node amp vice versa Why amp where encapsulation needed

AnsOne fundamental feature of the GSM system is the automatic worldwide localization of users The system always knows where a user currently is and the same phone number is valid worldwide To provide this service GSM performs periodiclocation updates even if a user does not use the mobile station (provided that the MS is still logged into the GSM network and is not completely switched off) The HLR always contains information about the current location (only the location area not the precise geographical location) and the VLR currently responsible for the MS informs the HLR about location changes As soon as an MS moves into the range of a new VLR (a new location area) the HLR sends all user data needed to the new VLR Changing VLRs with uninterrupted availability of all services is also called roaming Roaming can take place within the network of one provider between two providers in one country (national roaming isoften not supported due to competition between operators) but also between different providers in different countries (international roaming) Typically people associate international roaming with the term roaming as it is this type of roaming that makes GSM very attractive one device over 190 countriesTo locate an MS and to address the MS several numbers are needed

Mobile node (MN) A mobile node is an end-system or router that can

change its point of attachment to the internet using mobile IP The MN

keeps its IP address and can continuously communicate with any other

system in the internet as long as link-layer connectivity is given Mobile

nodes are not necessarily small devices such as laptops with antennas or

mobile phones a router onboard an aircraft can be a powerful mobile node

Correspondent node (CN) At least one partner is needed for communication

In the following the CN represents this partner for the MN The CN

can be a fixed or mobile node

Home network The home network is the subnet the MN belongs to

with respect to its IP address No mobile IP support is needed within the

home network

Foreign network The foreign network is the current subnet the MN visits

and which is not the home network

Foreign agent (FA) The FA can provide several services to the MN during

its visit to the foreign network The FA can have the COA (defined below)

acting as tunnel endpoint and forwarding packets to the MN The FA can be

the default router for the MN FAs can also provide security services because

they belong to the foreign network as opposed to the MN which is only visiting

For mobile IP functioning FAs are not necessarily needed Typically

an FA is implemented on a router for the subnet the MN attaches to

Care-of address (COA) The COA defines the current location of the MN

from an IP point of view All IP packets sent to the MN are delivered to the

COA not directly to the IP address of the MN Packet delivery toward the

MN is done using a tunnel as explained later To be more precise the COA

marks the tunnel endpoint ie the address where packets exit the tunnel

There are two different possibilities for the location of the COA

Foreign agent COA The COA could be located at the FA ie the COA

is an IP address of the FA The FA is the tunnel end-point and forwards

packets to the MN Many MN using the FA can share this COA as

common COA

Co-located COA The COA is co-located if the MN temporarily acquired

an additional IP address which acts as COA This address is now topologically

correct and the tunnel endpoint is at the MN Co-located addresses

can be acquired using services such as DHCP (see section 82) One problem

associated with this approach is the need for additional addresses if

MNs request a COA This is not always a good idea considering the

scarcity of IPv4 addresses

Home agent (HA) The HA provides several services for the MN and is located

in the home network The tunnel for packets toward the MN starts at the HA

The HA maintains a location registry ie it is informed of the MNrsquos location

by the current COA Three alternatives for the implementation of an HA exist

The HA can be implemented on a router that is responsible for the

home network This is obviously the best position because without

optimizations to mobile IP all packets for the MN have to go through

the router anyway

If changing the routerrsquos software is not possible the HA could also be

implemented on an arbitrary node in the subnet One disadvantage of

this solution is the double crossing of the router by the packet if the MN

is in a foreign network A packet for the MN comes in via the router the

HA sends it through the tunnel which again crosses the router

Finally a home network is not necessary at all The HA could be again

on the lsquorouterrsquo but this time only acting as a manager for MNs belonging

to a virtual home network All MNs are always in a foreign network

with this solution

The example network in Figure 81 shows the following situation A CN is

connected via a router to the internet as are the home network and the foreign

network The HA is implemented on the router connecting the home network

with the internet an FA is implemented on the router to the foreign network

The MN is currently in the foreign network The tunnel for packets toward the

MN starts at the HA and ends at the FA for the FA has the COA in this example

IP packet delivery

packet delivery to and from the MN using the example network

of Figure 81 A correspondent node CN wants to send an IP packet to the

MN One of the requirements of mobile IP was to support hiding the mobility of

the MN CN does not need to know anything about the MNrsquos current location

and sends the packet as usual to the IP address of MN (step 1) This means that

CN sends an IP packet with MN as a destination address and CN as a source

address The internet not having information on the current location of MN

routes the packet to the router responsible for the home network of MN This is

done using the standard routing mechanisms of the internet

The HA now intercepts the packet knowing that MN is currently not in its

home network The packet is not forwarded into the subnet as usual but encapsulated

and tunnelled to the COA A new header is put in front of the old IP

header showing the COA as new destination and HA as source of the encapsulated

packet (step 2) (Tunneling and encapsulation is described in more detail

in section 816) The foreign agent now decapsulates the packet ie removes

the additional header and forwards the original packet with CN as source and

MN as destination to the MN (step 3) Again for the MN mobility is not visible

It receives the packet with the same sender and receiver address as it would have

done in the home network

Ans- 12 Wireless access techinques used are

1G- FDMA

2G- FDMA TDMA

25G- TDMA based GSM SystemCDMA

3G- CDMA2000WCDMA

Three Classes of wireless data networking are

1 Wireless Personal Area Networks (WPANs)

2 Wireless LAN

3 Wireless MAN

4 WirelessWAN

Q13 Define the roles of WPAN technology in wireless data networking

Ans IEEE 802154-2003 standard for Low-Rate Wireless Personal Area Networks (LR-WPANs) such as wireless light switches with lamps electrical meters with in-home-displays consumer electronics equipment via short-range radio needing low rates of data transfer The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs such as Bluetooth ZigBee is targeted at radio-frequency (RF) applications that require a low data rate long battery life and secure networking

WPAN technologies enable users to establish ad hoc wireless communications for devices (such as PDAs cellular phones or laptops) that are used within a personal operating space (POS) A POS is the space surrounding a person up to a distance of 10 meters Currently the two key WPAN technologies are Bluetooth and infrared light Bluetooth is a cable replacement technology that uses radio waves to transmit data to a distance of up to 30 feet Bluetooth data can be transferred through walls pockets and briefcases Technology development for Bluetooth is driven by the Bluetooth Special Interest Group (SIG) which published the Bluetooth version 10 specification in 1999 Alternatively to connect devices at a very close range (1 meter or less) users can create infrared links

To standardize the development of WPAN technologies IEEE has established the 80215 working group for WPANs This working group is developing a WPAN standard based on the Bluetooth version 10 specification Key goals for this draft standard are low complexity low power consumption interoperability and coexistence with 80211 networks

Q14 List the main features of 3G systems

AnsMain features of 3G System are

The most significant features of the 3G technology is that is supports greater voice and data capacity and higher data transfer rate at the lowest cost both in the rural and urban areas 3G uses the radio spectrum which allows the transmission of 384 kbs for the mobile systems and the 2mbs for the stationary systems Today more

telecommunication networks in the world are being upgraded to the 3G technologies because of its greater features scalability higher voice and data transfer rates and better performance than the 2G tec

Combines a mobile phone laptop PC and TV Features includes- Phone callsfax- Global roaming- Sendreceive large email messages- High-speed WebNavigationmapsVideoconferencing- TV streaming- Electronic agenda meeting reminder

Speed 144kbsec-2mbsec

Time to download a 3min MP3 song 11sec-15min

Q15 What is the role of GPRS in enhancing 2G GSM system

ANS General Packet Radio Service (GPRS) in GSMGPRS has been standardized to optimally support a wide range ofapplications ranging from very frequent transmission of medium to large data volume andinfrequent transmission of large data volume Services of GPRS have been developed toreduce connection setup time and allow an optimum usage of radio resources GPRS providesa packet data service for GSM where time slots on the air interface can be assignedto GPRS over which packet data from several mobile stations is multiplexed

GPRS provides a core network platform for current GSM operators not only to expandthe wireless data market in preparation for the introduction of 3G services but also a platformon which to build IMT-2000 frequencies should they acquire them

GPRS enhances GSM data services significantly by providing end-to-end packetswitcheddata connections This is particularly efficient in Internetintranet traffic whereshort bursts of intense data communications activity are interspersed with relatively longperiods of inactivity Because there is no real end-to-end connection to be established settingup a GPRS call is almost instantaneous and users can be continuously online Usershave the additional benefit of paying for the actual data transmitted rather than for connectiontimeBecause GPRS does not require any dedicated end-to-end connection it only uses networkresources and bandwidth when data is actually being transmitted This means that agiven amount of radio bandwidth can be shared efficiently and simultaneously among manyusers

The implementation of GPRS has a limited impact on the GSM core network It simplyrequires the addition of new packet data switching and gateway nodes and an upgradeto existing nodes to provide a routing path for packet data between the wireless terminaland a gateway node The gateway node provides interworking with external packet data networks

for access to Internet intranets and databases

A GPRS architecture for GSM is shown in Figurehelliphellip

GPRS will support all widelyused data communications protocols including IP so it will be possible to connect with anydata source from anywhere in the world using a GPRS mobile terminal GPRS will supportapplications ranging from low-speed short messages to high-speed corporate LAN communicationsHowever one of the key benefits of GPRSmdashthat it is connected through the existingGSM air interface modulation schememdashis also a limitation restricting its potential fordelivering data rates higher than 115 kbps To build even higher rate data capabilities intoGSM a new modulation scheme is needed

GPRS can be implemented in the existing GSM systems It requires only minorchanges in an existing GSM network The base station subsystem (BSS) consists of basestation controller (BSC) and packet control unit (PCU) The PCU supports all GPRS protocolsfor communication over the air interface Its function is to set up supervise and disconnect

packet-switched calls PCU supports cell change radio resource configuration andchannel assignment The base transceiver station (BTS) is a relay station without protocolfunctions It performs modulation and demodulation

The GPRS standard introduces two new nodes the serving GPRS support node(SGSN) and the gateway GPRS support node (GGSN) The home location register (HLR)is enhanced with GPRS subscriber data and routing information Two types of services areprovided by GPRSbull Point-to-point (PTP)bull Point-to-multipoint (PTM)

Packet data transmission speeds were later increased via EDGE for 2G GSM Enhanced

Data rates for GSM Evolution (EDGE) (also known as Enhanced GPRS (EGPRS) is a digital mobile phone technology that allows improved data transmission rates as a backward-compatible extension of GSM EDGE is considered a pre-3G radio technology and is part of ITUs 3G definition EDGE is standardized by 3GPP as part of the GSM family EDGE can be used for any packet switched application such as an Internet connection

EDGE provides an evolutionary path that enables existing 2G systems (GSM IS-136) todeliver 3G services in existing spectrum bands The advantages of EDGE include fast availabilityreuse of existing GSM IS-136 and PDC infrastructure as well as support for gradualintroduction of 3G capabilitiesEDGE reuses the GSM carrier bandwidth and time slot structure EDGE can be seenas a generic air interface for efficiently providing high bit rates facilitating an evolution ofexisting 2G systems toward 3G systemsEDGE (25G system) [78] was designed to enhance user bandwidth through GPRS

This is achieved through the use of higher-level modulation schemes Although EDGEreuses the GSM carrier bandwidth and time slot structure the technique is by no meansrestricted to GSM systems it can be used as a generic air interface for efficient provisionof higher bit rates in other TDMA systems In the Universal Wireless CommunicationsConsortium (UWCC) the 136 high-speed (136 HS) radio interface was proposed as ameans of satisfying the requirements for an IMT-2000 RTT EDGE was adopted by UWCCin 1998 as the outdoor component of 136 HS to provide 384-kbps data serviceThe standardization effort for EDGE has two phases In the first phase the emphasishas been placed on enhanced GPRS (EGPRS) and enhanced CSD (ECSD) The secondphase is being defined with improvements for multimedia and real-time services as possiblework itemsEDGE is primarily a radio interface improvement but it can also be viewed as a systemconcept that allows GSM and IS-136 networks to offer a set of new services EDGE hasbeen designed to improve SI by using link quality control Link quality control adapts theprotection of the data to the channel quality so that an optimal bit rate is achieved for allchannel qualities

The EDGE air interface is designed to facilitate higher bit rates than those currentlyachievable in existing 2G systems The modulation scheme based on 8-PSK is used toincrease the gross bit rate GMSK modulation as defined in GSM is also part of the EDGEsystem The symbol rate is 271 kbps for both GMSK and 8-PSK leading to gross bit ratesper time slot of 228 kbps and 692 kbps respectively The 8-PSK pulse shape is linearized

GMSK to allow 8-PSK to fit into the GSM spectrum mask The 8-PSK burst format is similarto GSM

In order to achieve a higher gross rate a new modulation scheme quaternary offsetquadrature amplitude modulation (QOQAM) has been proposed for EDGE since it canprovide higher data rates and good spectral efficiency An offset modulation scheme isproposed because it gives smaller amplitude variation than 16-QAM which can be beneficialwhen using nonlinear amplifiers EDGE will coexist with GSM in the existing frequencyplan and will provide link adaptation (ie modulation and coding are adapted forchannel conditions)

Radio Protocol DesignThe radio protocol strategy in EDGE is to reuse the protocols of GSMGPRS whenever possiblethus minimizing the need for new protocol implementation EDGE enhances bothGSM circuit-switched (HSCSD) and packet-switched (GPRS) mode operation EDGEincludes one packet-switched (PS) and one circuit-switched (CS) mode EGPRS andECSD respectivelyEnhanced GPRS (EGPRS) The EDGE radio link control (RLC) protocol is somewhatdifferent from the corresponding GPRS protocol The main changes are related to improvementsin the link quality control schemeA link adaptation scheme regularly estimates the link quality and subsequently selectsthe most appropriate modulation and coding scheme for transmission to maximize the user

bit rate The link adaptation scheme offers mechanisms for choosing the best modulationand coding alternative for the radio link In GPRS only the coding schemes can be changedbetween two consecutive link layer control (LLC) frames In the EGPRS even the modulationcan be changed Different coding and modulation schemes enable adjustment for therobustness of the transmission according to the environment

Services Offered by EDGEPS Services The GPRS architecture provides IP connectivity from mobile station to anexternal fixed IP network For each service a quality of service (QoS) profile is definedThe QoS parameters include priority reliability delay and maximum and mean bit rate Aspecified combination of these parameters defines a service and different services can be

selected to suit the needs of different applicationsCS Services The current GSM standard supports both transparent and nontransparentservices Eight transparent services are defined offering constant bit rates in the range of96 to 64 kbps

Thus EDGE CS transmission makes the high-bit-rate services available with fewertime slots which is advantageous from a terminal implementation perspective Additionallymore users can be accepted since each user needs fewer time slots which increases thecapacity of the system

Q16show how CDMA IS-95 systems are moving to provide 3G services

Soluiton16

2G CDMA Cellular (IS-95)

GSM uses TDMA but who uses CDMA in 2G While some systems have appeared IS-95 is

the best-known example of 2G with CDMA Recall that in the case of CDMA each user is

assigned a unique code that differentiates one user from others This is in contrast to TDMA

where each user is assigned a time slot Why use CDMA for cellular Although the debate

between CDMA versus TDMA has been raging for a while (see Section 855) there are

several advantages of CDMA for cellular networks The main advantage of CDMA is that

many more users (up to 10 times more) can be supported as compared to TDMA Although

this leads to some complications (see Section 855) the advantage of supporting more users

far outweighs the disadvantage of added complexity

The IS-95 cellular system has different structures for its forward (base station to mobile

station) and backward links The forward link consists of up to 64 logical CDMA channels

each occupying the same 1228 kHz bandwidth The forward channel supports 4 different

types of channels

1048707 Traffic channels (channels 8 to 31 and 33 to 63) ndash these 55 channels are used to

carry the

user traffic (originally at 96 Kbps revised at 144 Kbps)

1048707 Pilot (Channel 0) ndash used for signal strength comparison among other things to

determine

handoffs

1048707 Synchronization (Channel 32) ndash a 1200 bps channel used to identify the cellular

system

(system time protocol revision etc)

1048707 Paging (channels 1 to 7) ndash messages for mobile stations

All these channels use the same frequency band ndash the chipping code (a 64-bit code) is used to

distinguish between users Thus 64 users can theoretically use the same band by using

different codes This is in contrast to TDMA where the band has to be divided into slots ndash one

slot per user The voice and data traffic is encoded assigned a chipping code modulated and

sent to its destination The data in the reverse travels on the IS-95 reverse links The reverse

links consist of up to 94 logical CDMA channels each occupying the 1228 kHz bandwidth

The reverse link supports up to 32 access channels and up to 62 traffic channels The reverse

links support many mobile unit-specific features to initiate calls and to update location during

handoffs

The overall architecture of 2G CDMA-based systems are similar to the TDMA-based GSM

systems (see Figure 8-10) The main difference is that the radio communication between the

Base Station Subsystem and Mobile System uses CDMA instead of TDMA Of course the

MSC now has to worry about handling soft handoffs but the overall structure stays the same

855 Controversy CDMA Versus TDMA

There are conflicting performance claims for CDMA and TDMA The debate is raging

because hardware vendors have chosen sides and consequently the standardizing bodies have

been lobbied hard The primary motivation for this level of debate is that vendors want their

selection to become the industry standard Since both TDMA and CDMA have become TIA

(Telecom Industry Association) standards ndash IS-54 and IS-95 respectively ndash the debate goes

on to determine which standard is better Technically speaking CDMA has the following

advantages over TDMA

1048707 Network capacity In CDMA the same frequency can be reused in adjacent

cells

because the user signals differentiate from each other by a code Thus frequency reuse

can be very high and many more users (up to 10 times more) can be supported as

compared to TDMA

1048707 Privacy Privacy is inherent in CDMA since spread spectrum modulates data to

signals

randomly (you cannot understand the signal unless you know the randomizing code)

1048707 Reliability and graceful degradation CDMA-based networks only gradually

degrade

as more users access the system This is in contrast to the sudden degradation of TDMAbased

systems For example if the channel is divided between ten users then the eleventh

user can get a busy signal in a TDMA system This is not the case with CDMA because

there is no hard division of channel capacity ndash CDMA can handle users as long as it can

differentiate between them In case of CDMA the noise and interference increases

gradually as more users are added because it becomes harder to differentiate between

various codes

1048707 Frequency diversity CDMA uses spread spectrum thus transmissions are

spread over a

larger frequency bandwidth Consequently frequency-dependent transmission

impairments that occur in certain frequency ranges have less effect on the signal

1048707 Environmental Since existing cells can be upgraded to handle more users the

need for

new cell towers decreases

But there are some drawbacks of CDMA cellular also

1048707 Relatively immature As compared to TDMA CDMA is a relatively new

technology

but it is catching up fast

1048707 Self-jamming CDMA works better if all mobile users are perfectly aligned on

chip

(code) boundaries If this is not the case then some interference can happen This

situation is better with TDMA and FDMA because time and frequency guard bands can

be used to avoid the overlap

1048707 Soft handoff An advantage of CDMA is that it uses soft handoff (ie two cells

can own

a mobile user for a while before the handoff is complete) However this requires that the

mobile user acquires the new cell before it relinquishes the old ndash a more complex process

than hard handoff used in FDMA and TDMA schemes

The main advantage of CDMA is that the frequency reuse can be very high and many more

users can be supported in a cell as compared to TDMA Although this leads to a soft handoff

that is more complicated than the hard handoff used in TDMA the advantage of supporting

more users far outweighs the disadvantage of added complexity

Q17show how 2G GSm systems are moving to achieve 3G services

ANS

A Step-by-Step Towards IMT-2000 (UMTS)

GSM at 96 Kbps

HSCSD dial-up access at up to

576 Kbps

GPRS variable speeds depending on configuration ~ 14 and 28 Kbps

by mid-2001

EDGE up to 384 Kbps

UMTS at 384 Kbps and a max speed of 2 Mbps

GSM at 96 Kbps

HSCSD dial -up access at up to

576 Kbps

GPRS variable speeds depending

on configuration ~ 57 and 114 Kbps

by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS

The development of the digital technology on one hand and frequent cases when analog systems reached their full capacity especially in big cities on the other hand led to the development of the second-generation (2G) systems

The main aim in the design of the 2G systems was the maximization of the system capacity measured as the number of users per spectrum per unit area

2G networks are digital both systems use digital signaling to connect the radio towers (which listen to the handsets) to the rest of the telephone system

Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted more efficient on the spectrum allowing for far greater mobile phone penetration levels and data services for mobile starting with SMS

CAPACITY OF 2G SYSTEM

Using digital signals system capacity in two key ways

Digital voice data can be compressed and multiplexed much more effectively than analog voice encodings through the use of various codecs allowing more calls to be packed into the same amount of radio bandwidth

The digital systems were designed to emit less radio power from the handsets The cells are smaller so more cells could be placed in the same amount of space

DRAWBACKS OF 2G

There are drawbacks to the current GSM

The GSM is a circuit switched connection oriented technology where the end systems are dedicated for the entire call session This causes inefficiency in usage of bandwidth and resources

The GSM-enabled systems do not support high data rates

They are unable to handle complex data such as video

These devices have small hardware configurations with less powerful CPUs memory and display units and support simple functionality

Only basic messaging services such as SMS can be supported

The GSM networks are not compatible with the current TCPIP and other common networks because of differences in network hardware software and protocols

Evolution of Wireless Sys (25G)

bull 2G telephony is highly successful

bull Enhancement to 2G on data service

ndash GSM HSCSD and GPRS

ndash IS-95 IS-95b

ndash IS-136 D-AMPS+ and CDPD

bull The improved data rate is still too low to support multimedia traffic

bull ITU initiated 3G standardization effort in 1992 and the outcome is IMT-2000

Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality

Higher rates 2048 Mbps for low speed users 384 Kbps for modest speed users and 144 Kbps for high speed users

More reliable and larger capacity

Compatible with 2G systems

More flexible

Support both circuit-switching and packet-switching

Work in hierarchical mode with pico-micro-macro-cells

Support asymmetric services

Paradigm From 1G to Beyond 3G

2G EVOLUTION TO 3G

Q18what are the data rate requirements for 3g system

Third generation cellular systems are being designed to support wideband services

like high speed Internet access video and high quality image transmission with the same

quality as the fixed networks The primary requirements of the next generation cellular

systems are [1]

bull Voice quality comparable to Public Switched Telephone Network (PSTN)

bull Support of high data rate The following table shows the data rate requirement of

the 3G systems

Table 11 3G Data Rate Requirements

Mobility Needs Minimum Data RateVehicular 144 kbps

Outdoor to indoor and pedestrian 384 kbps

Indoor Office 2 Mbps

bull Support of both packet-switched and circuit-switched data services

bull More efficient usage of the available radio spectrum

bull Support of a wide variety of mobile equipment

bull Backward Compatibility with pre-existing networks and flexible introduction of

new services and technology

bull An adaptive radio interface suited to the highly asymmetric nature of most

Internet co

Q 19 define ip wireless tecnology

IPWireless is the broadband technology based upon UMTS( Universal Mobile

Telecommunications System) It uses either 5 or 10 MHz TDD carriers and

QPSK(quadrature phase shift keying ) modulation The theoretical peak transmission speeds for a 10MHz deployment are 6 Mbps downlink and 3 Mbps uplink The IPWireless system only uses QPSK modulation and no advanced antenna technologies With the inclusion of advanced antenna technologies and the development of High-Speed Downlink Packet Access (HSDPA) IPWireless has signifi cant potential

SOMA networks has also developed a wireless broadband technology based on UMTS Like

UMTS SOMArsquos technology uses 5 MHz FHSS carriers Peak throughput is claimed to be as

high as 12 Mbps making SOMA one of the faster wireless broadband technologies

mmunications a much greater bandwidth for the downlink than the uplink

Q20 compare 3g and 4gMotivation for 4G Research Before 3G Has Not Been Deployed

1 3G performance may not be sufficient to meet needs of future high-performance applications like multi-media full-motion video wireless teleconferencing We need a network technology that extends 3G capacity by an order of magnitude

2 There are multiple standards for 3G making it difficult to roam and interoperate across networks we need global mobility and service portability

3 3G is based on primarily a wide-area concept We need hybrid networks that utilize both wireless LAN (hot spot) concept and cell or base-station wide area network design

4 We need wider bandwidth

5 Researchers have come up with spectrally more efficient modulation schemes that can not be retrofitted into 3G infrastructure

6 We need all digital packet network that utilizes IP in its fullest form with converged voice and data capability

Comparing Key Parameters of 4G with 3G

3G (including 25G sub3G)

4G

Major Requirement Driving Architecture

Predominantly voice driven - data was always add on

Converged data and voice over IP

Network Architecture

Wide area cell-based Hybrid - Integration of Wireless LAN (WiFi Bluetooth) and wide area

Speeds 384 Kbps to 2 Mbps 20 to 100 Mbps in mobile mode

Frequency Band

Dependent on country or continent (1800-2400 MHz)

Higher frequency bands (2-8 GHz)

Bandwidth 5-20 MHz 100 MHz (or more)

Switching Circuit and Packet All digital with

Design Basis packetized voice

Access Technologies

W-CDMA 1xRTT Edge

OFDM and MC-CDMA (Multi Carrier CDMA)

Forward Error Correction

Convolutional rate 12 13

Concatenated coding scheme

Component Design

Optimized antenna design multi-band adapters

Smarter Antennas software multiband and wideband radios

IP A number of air link protocols including IP 50

All IP (IP60)

Ques21 What is multi input multi output (MIMO) system Explain

Answer Systems with more than one input or more than one output are known as Multi-Input Multi-Output systems MIMO is the use of multiple antennas at both the transmitter and receiver to improve communication performance It is one of several forms of smart antenna technology The terms input and output refer to the radio channel carrying the signal not to the devices having antennas MIMO technology has attracted attention in wireless communications because it offers significant increases in data throughput and link range without additional bandwidth or transmit power It achieves this by higher spectral efficiency have more bits per second per hertz of bandwidth and link reliability or diversity Because of these properties MIMO is an important part of modern wireless communication standards such as IEEE 80211n (Wifi) 4G WiMAX etc

MIMO Technology Uses Multiple Radios to Transfer More Data at the Same Time

MIMO technology leverages multipath behavior by using multiple ldquosmartrdquo transmitters and receivers with an added ldquospatialrdquo dimension to dramatically increase performance and range MIMO allows multiple antennas to send and receive multiple spatial streams at the same time This allows antennas to transmit and receive simultaneously

MIMO makes antennas work smarter by enabling them to combine data streams arriving from different paths and at different times to effectively increase receiver signal-capturing power Smart antennas use spatial diversity technology which puts surplus antennas to good use In order to implement MIMO either the station (mobile device) or the access point (AP) need to support MIMO Optimal performance and range can only be obtained when both the station and the AP support MIMO

Legacy wireless devices canrsquot take advantage of multipath because they use a Single Input Single Output (SISO) technology Systems that use SISO can only send or receive a single spatial stream at one time

MIMO technology takes advantage of a radio-wave phenomenon called multipath where transmitted information bounces off walls ceilings and other objects reaching the receiving antenna multiple times via different angles and at slightly different times

Question 22 What is the software defined radio system

Answer Software Defined Radio (SDR) refers to the technology wherein software modules running on a generic hardware platform consisting of DSPs

and general purpose microprocessors are used to implement radio functions such as generation of transmitted signal (modulation) at transmitter and tuningdetection of received radio signal (demodulation) at receiver A radio that includes a transmitter in which the operating parameters of the transmitter including the frequency range modulation type or maximum radiated or conducted output power can be altered by making a change in software without making any hardware changes A basic SDR system may consist of a personal computer equipped with a sound card or other analog-to-digital converter preceded by some form of RF front end Significant amounts of signal processing are handed over to the general-purpose processor rather than being done in special-purpose hardware Such a design produces a radio which can receive and transmit widely different radio protocols (sometimes referred to as a waveforms) based solely on the software used

Software radios have significant utility for the military and cell phone services both of which must serve a wide variety of changing radio protocols in real time

Software-defined radios are expected by proponents like the SDRForum (now The Wireless Innovation Forum) to become the dominant technology in radio communications SDRs along with software defined antennas are the enablers of the cognitive radio

Motivation of SDRCommercial wireless communication industry is currently facing problems due to constant evolution of link-layer protocol standards (25G 3G and 4G) existence of incompatible wireless network technologies in different countries inhibiting deployment of global roaming facilities problems in rolling-out new features due to wide-spread presence of legacy subscriber handsets

Applications

Military Real-time flexibility Secure International connectivity Portable command for crisis management Bluetooth WLAN GPS Radar WCDMA GPRS GSM AM FM etcFeatures Reconfigurability future-proof multi-service multi-mode multiband multi-standard terminals and infrastructure equipment Ubiquitous Connectivity Interoperability SDR facilitates implementation of open architecture radio

systemsProgrammability Hardware radio no software changes Software controlled radio in PDR BB operations and link layer protocols are implemented in software

Question 23 List some of the new technologies that will be used in the 4G system

Answer The new technologies used in the 4G system are 4G mobile systems focus on seamless integration of existing wireless technologies including WWAN WLAN and Bluetooth 4G standards setting peak speed requirements for 4G service at 100 Mbits for high mobility communication (such as from trains and cars) and 1 Gbits for low mobility communication (such as pedestrians and stationary users) The 4G systems will encompass all systems from various networks public to private operator-driven broadband networks to personal areas and ad hoc networks The 4G intends to integrate from satellite broadband to high altitude platform to cellular 2G and 3G systems to wireless local loop (WLL) and broadband wireless access (BWA) to WLAN and wireless personal area networks (WPANs) A 4G system is expected to provide a comprehensive and secure all-IP based mobile broadband solution to laptop computer wireless modems smartphones and other mobile devices Facilities such as ultra-broadband Internet access IP telephony gaming services and streamed multimedia may be provided to users A 4G system can provide a comprehensive IP solution where voice data and streamed multimedia can be provided to users on an Anytime Anywhere basis The data transfer rates are also much higher than previous generationsThe main objectives of 4G are-1) 4G will be a fully IP-based integrated system2) This will be capable of providing 100 Mbits and 1 Gbits speeds both indoors and outdoors3) It can provide premium quality and high security4) 4G offer all types of services at an affordable cost4G is developed to provide high quality of service (QoS) and rate requirements set by forthcoming applications such as wireless broadband access Multimedia Messaging Video Chat Mobile TV High definition TV content DVB minimal service like voice and data and other streaming services 4G technology allow high-quality smooth video transmission It will enable fast downloading of full-

length songs or music pieces in real time 4G mobile data transmission rates are planned to be up to 20 megabits per second which means that it will be about 10-20 times faster than standard ASDL services

Technologies

Multicarrier Modulation Multicarrier modulation (MCM) is a derivative of frequency-division multiplexing It is not a new technology Forms of multicarrier systems are currently used in DSL modems and digital audiovideo broadcast (DABDVB) MCM is a baseband process that uses parallel equal bandwidth sub channels to transmit information and is normally implemented with fast Fourier transform (FFT) techniques MCMrsquos advantages are better performance in the inter-symbol-interference environment and avoidance of single-frequency interferers

Smart Antenna Techniques Smart antenna techniques such as multiple-input multiple-output (MIMO) systems can extend the capabilities of the 3G and 4G systems to provide customers with increased data throughput for mobile high-speed data applications MIMO systems use multiple antennas at both the transmitter and receiver to increase the capacity of the wireless channel

Single-input multiple-output There are N antennas at the receiver If the signals received on the antennas have on average the same amplitude then they can be added coherently to produce an N2 increase in signal power

Multiple-input single-output We have M transmitting antennas The total power is divided into M transmitter branches

Multiple-input multiple-output MIMO systems can be viewed as a combination of MISO and SIMO channels

OFDM-MIMO Systems OFDM and MIMO techniques can be combined to achieve high spectral efficiency and increased throughput The OFDM-MIMO system transmits independent OFDM modulated data from multiple antennas simultaneously At the receiver after OFDM demodulation MIMO decodes each subchannel to extract data from all transmit antennas on all the subchannels

Qno 24 What is the basic requirement amp entity involed for the mobility management

Ans MOBILITY MANAGEMENT

Mobility management contains two componentsLocation management and handoff management [2]

A Location Management

Location management is a two-stage process that enablesthe network to discover the current attachment point of themobile user for call delivery as shown in Fig 1 The firststage is location registration (or location update) In this stagethe mobile terminal periodically notifies the network of its newaccess point allowing the network to authenticate the user andrevise the userrsquos location profile The second stage is call delivery Here the network is queried for the user location profile and the current position of the mobile host is found

Fig1 Location management operations

B Handoff Management

Handover (or handover) management enables the network tomaintain a userrsquos connection as the mobile terminal continues Mobility Management in Next-GenerationWireless Systems

Fig 2 Handoff management operations

To move and change its access point to the network The threestage process for handoff first involves initiation where either the user a network agent or changing network conditions identify the need for handoff The second stage is new connection generation where the network must find new resources for the handoff connection and perform any additional routing operations Under network-controlled handoff (NCHO)[11] or mobile-assisted handoff (MAHO) the network generates a new connection finding new resources for the handoff and performing any additional routing operations For mobile-controlled handoff (MCHO)[10] the mobile terminal finds the new resources and the network approves The final stage is data-flow control where the delivery of the data from the old connection path to the new connection path is maintained according to agreed upon service mobile terminal finds the new resources and the network approves The final stage is data-flow control wherethe delivery of the data from the old connection path to the new connection path is maintained according to agreed-upon service guarantees The handoff management operations are presented in Fig 2

Handoff management includes two conditions

Intracell handoff and intercell handoff

Intracell handoff occurs when the user moves within a service area (or cell) and experiences signal strength deterioration below a certain threshold that results in the transfer of the userrsquos calls to new radio channels of appropriate strength at the same base station (BS) [11]

Intercell handoff occurs when the user moves into an adjacent cell and all of the terminalrsquos connections must be transferred to a new BS While performing handoff the terminal may connect to multiple BSrsquos simultaneously and use some form of signaling diversity to combine the multiple signals This is called soft handoff On the other hand if the terminal stays connected to only one BS at a time clearing the connection with the former BS immediately before or after establishing a connection with the target BS then the process is referred to as hard handoff

MOBILITY MANAGEMENT FOR THE PLMN

In ordinary wire line networks such as the telephonenetwork there is a fixed relationship between a terminal andits location[8] Changing the location of a terminal generally involves the network administration and it cannot easily be performed by a user Incoming calls for a particular terminal are always routed to its associated location as there is no distinction between a terminal and its location [9] In contrast mobile terminals (MTrsquos) are free to travel and thus the network access point of an MT changes as it moves around the network coverage area As a result the ID of an MT does not implicitly provide the location information of the MT and the call delivery process becomes more complex In order to perform the registration update and call delivery operations described above the network stores the location information of each MT in the location databases Then the information can be retrieved for call deliveryCurrent schemes[3] for PLMN location management arebased on a two-level data hierarchy such that two types of network location database the home location register (HLR) and the visitor location register (VLR) are involved in tracking an MT In general there is an HLR for each network and a User is permanently associated with an HLR in hisher subscribed network Information about each user such as the types of services subscribed and location information are stored in a user profile located at the HLR The number of VLRrsquos and their placements vary among networks Each

VLR stores the information of the MTrsquos (downloaded from the HLR) visiting its associated area

Fig 3 SS7 signaling network

Network management functions such as call processing and location registration are achieved by the exchange of signaling messages through a signaling network Signaling System 7 (SS7) [5] is the protocol used for signaling exchange and the signaling network is referred to as the SS7 network the type of CSS currently implemented for the PLMN is known as a mobile switching center (MSC) Fig 3 shows the SS7 signaling network which connects the HLR the VLRrsquos and the MSCrsquos in a PLMN based network The signal transfer points (STPrsquos) as shown in Fig 3 are responsible for routing signaling Messages within the SS7 network For reliability reason the STPrsquos are installed in pairs As mentioned previously location management includes two major tasks location registration (or update) and calldelivery (see Fig 1) For PLMN the location registrationprocedures update the location databases (HLR and VLRrsquos)and authenticate the MT when up-to-date location informationof an MT is available The call delivery procedures locate the MT based on the information available at the HLR and the VLRrsquos when a call for an MT is initiated The IS-41 and the GSM MAP location management strategies are very similar to each other While GSM MAP is designed to facilitate personal mobility and to enable user selection of network provider there are a lot of commonalities between the two standards

1 Location Registration In order to correctly deliver calls the PLMN must keep track of the location of each MT As described previously location information is stored in two types of databases VLR and HLR As the MTrsquos move around the network coverage area the data stored in these databases To ensure that calls can be delivered successfully the databases are periodically updated through the process called location registrationLocation registration is initiated by an MT when it reports its current location to the network We call this reporting process location update Current systems adopt an approach such that the MT performs a location update whenever it enters a new LA Recall that each LA consists of a number of cells and in general all BTSrsquos belonging to the same LA is connected to the same MSC When an MT enters an LA if the new LA belongs to the same VLR as the old LA the record at the VLR is updated to record the ID of the new LA [14] Otherwise if the new LA belongs to a different VLR a number of extra steps are required to 1) register the MT at the new serving VLR 2) update the HLR to record the ID of the new serving VLR and3) deregister the MT at the old serving VLR Fig 4 shows the location registration procedure when an MT moves to a newLA The following is the ordered list of tasks that areperformed during location registration The MT enters a new LA and transmits a location updatemessage to the new BS The BS forwards the location update message to the MSC which launches a registration query to its associated VLR The VLR updates its record on the location of the MT If the new LA belongs to a different VLR the new VLR determines the address of the HLR of the MT from its mobile identification number (MIN) [10] This is achieved by a table lookup procedure called global title translation The new VLR then sends a location registration message to the HLR Otherwise location registration is completeThe HLR performs the required procedures to authenticate the MT and records the ID of the new serving VLR of the MT

Fig 4 Location registration procedures

The HLR then sends a registration acknowledgment messageto the new VLR

The HLR sends a registration cancellation message to the old VLR The old VLR removes the record of the MT and returns a cancellation acknowledgment message to the HLR Depending on the distance between the current and the home locations of the MT in steps 3)ndash6) the signaling messages may have to go through several intermediate STPrsquos before reaching their destinations For example a user who subscribes to wireless services in Atlanta will normally be assigned to an HLR located in the Atlanta area When this user is roaming in London each location update performed by hisher mobile phone will result in the transmission of four transatlantic SS7 messages [messages (3)ndash(6) as shown in Fig6] These messages may transverse a number of STPrsquos in the SS7[10] network before reaching their destinations which generate additional load to the network elements and the transmission links The location registration may therefore result in significant traffic load to the SS7 network As the number of mobile subscribers keeps increasing the delay for completing a location registration may increase

Fig6 Mobile IP location registration

Call Delivery Two major steps are involved in calldelivery

1) determining the serving VLR of the called MT and

2) locating the visiting cell of the called MT

Locating the serving VLR of the MT involves the following database ookup procedure (see Fig 5)

Fig 5 Mobile IP architecture

1 The calling MT sends a call initiation signal to the serving MSC of the MT through a nearby BS

2 The MSC determines the address of the HLR of the called MT by global title translation and sends a location request message to the HLR

3 The HLR determines the serving VLR of the called MT and sends a route request message to the VLR This VLR then forward the message to the MSC serving the MT

4 The MSC allocates a temporary identifier called temporary local directory number (TLDN) to the MT and sends a reply to the HLR together with the TLDN

5 The HLR forward this information to the MSC of the calling MT

6 The calling MSC requests a call set up to the called MSC through the SS7 network

The procedure described above allows the network to set upa connection from the calling MT to the serving MSC of the called MT Since each MSC is associated with an LA and there are more than one cell in each LA a mechanism is therefore necessary to determine the cell location of the called MT In current PLMN networks this is achieved by a paging (or alerting) procedure such that polling signals are broadcast to all cells within the residing LA of the called MT On receiving the polling signal the MT sends a reply which allows the MSC to determine its current residing cell As the number of MTrsquos increases sending polling signals to all cells in an LA whenever a call arrives may consume excessivewireless bandwidth

QNo 25 Compare various mobile devices like smartphone pc tablet and its various model available in the market

Ans Comparision bw smartphone and pc tablet

Technically both Tablet and Smartphone are designed to serve different purposes But these days every type of gadget is trying to incorporate into it the best features of other category gadgets to claim the title of an lsquoAll Purpose Machinersquo

A smartphone fulfills the criteria to a great extent In case you are not bewildered with the amazing feats that high end mobile handsets (affectionately referred to as smartphones these days) are capable of performing rewind your memory to one and a half decade back Back then mobile handsets usually had pathetic resolution and were lsquotechnically deficientrsquo (yup This is the term I would like to use) when compared with the phones of the present generation Ever since then the mobile market has tried hard to bridge the gap between a high resolution display system and a computer and simple mobile handset As a result of this smartphones today

are in a position to take head on the other devices in the broad spectrum of sleek electronic gadgets

While the smartphone may have become really smart still it has a long way to go to replace tablet PCrsquos The presence of a thriving market for tablet PCrsquos is a testimony to the fact there the consumers love tablet PCrsquos too as do they love smartphones In fact there are many tasks which are enjoyable on a tablet PC rather than a mobile handset Letrsquos talk about the unique strong points of both gadgets First and foremost the high resolution fully touch screen feature of tablet PCrsquos provides an ideal platform for content consumption The basic idea is to compromise on processing power (as compared to a laptop) to give a sizeable screen which resembles the size of a book The large screen with exceptional clarity which the Tablet PC has to offer canrsquot be replaced by a smartphone Whether you wish to chalk out business plans or check your mail a bigger screen is always better than a smaller one If content consumption with exceptional screen resolution is your forte then a tablet PC is simply irresistible Touching a pointing on a larger screen is definitely more fun Also if one is interested in light content creation then too the tablet PC scores above a smartphone

Writing mail or social networking on a laptop netbook or a tablet PC is always better than typing the same text on phone Itrsquos true that mobile handsets these days boast of QWERTY keyboards but still the miniature sized keys can never offer great speed Also for e-book reading nothing beats i-Pad (Applersquos tablet PC) For students too an i-Pad can supplement other sources and can make the process of learning easier and more efficient

Coming to smartphones they are the hottest gadgets in demand these days Reason ndash they can be comfortably carried around in a pocket and have processing power similar to a basic computer A smartphone is essentially designed to be handy throughout the day Checking mail sending business documents text messaging video calling social networking savoring music etc is achieved effortlessly at the push of a button It ideally connects you to the world To top all this AMOLED screens innumerable amazing apps nice cameras (resolution up to 8-10 mega pixels) further make life enjoyable Their popularity stems from the fact that you donrsquot feel carrying something while at work which is not the case with netbooks laptops or tablet PCrsquos

Swype Technology AllShare via DLNA Wireless Tethering Operation System (Googlersquos Android is in vogue) Mobile tracker Augmented Reality browser e-book reader LAYAR REALITY BROWSER Googletrade Turn-by-Turn Navigation and Social Hub are some cool features offered by smartphones They also boast of good RAM ROM and external memory Other regular features include Bluetooth Wifi calendar scheduler world time alarm currency converter memo book stopwatch countdown timer and a GPS mobile tracker

So the selection of one of the two (Tablet PC or Smartphone) depends basically on the type of use If you wish to consume content and engage in light content creation in your office or at home then a tablet PC offers exceptional visual experience Otherwise for business purpose (for being connected) a smartphone would be suitable Some people may need both So understand your needs and decide what you have to buy Both are priced at around Rs 25000

Models of smartphone-

Smartphones have emerged as the benchmark against which every mobile phone manufacturer seems to be judged by the market and the users alike There is a constant competition among the mobile phone vendors to outsmart each other by launching the most technologically advanced smartphone loaded with every possible application

Whether it is Apple or Nokia Samsung HTC or BlackBerry they all offer such an amazing ensemble of smartphones that it becomes too hard to pick the best ones Keeping in mind not just what is offered but also what is desired some of the best or perhaps more appropriately better than the rest smartphones would be

Apple iPhone 3G S Apples iPhone may not have been the first smartphone but it definitely was the one that made the biggest impact and was perhaps one of the most awaited launches ever Taking the same tradition forward Apples latest offering iPhone 3G S is also hits the spot It is faster than most looks impressive battery backup is better and of course works on 3G Moreover one of the hallmarks of iPhone that still remains is that owning one is treated by most as an honor (Buy iPhone 3G S in India)

RIM BlackBerry Curve 8900 RIMs BlackBerry was the harbinger of smartphones and what RIM adds to its range still keeps enthralling users Any list of top smartphones can never be complete without at least one of the BlackBerrys case in point Curve 8900 This BlackBerry works brilliantly has 32 megapixel camera and

overall is so good that the fact that it doesnt support 3G doesnt take anything away from the phone The GPS BlackBerry Maps Corporate Data Access and Entertainment features make BlackBerry Curve 8900 a great smartphone choice (BlackBerry Curve in India)

Nokia N97 Nokia is one of the most trusted names and best manufacturers in the mobile phones market and the same impact is carried into the smartphones segment with N97 To begin with it has great looks and supports 3G Its 5 megapixel camera takes great pictures and 32GB internal flash memory ensures it works amazingly well Its price could be a bit of a dampener but otherwise it sure is a good buy See Nokia N97 Review for more details (Buy Nokia N97 in India)

LG KM900 Arena LG offers many really cool smartphones and Arena is one of the best not only among LGs phones but also across other major smartphone brands It features a great TFT touchscreen supported by impressive interface Its 5 megapixel autofocus camera with LED flash captures pictures that youll love It supports 3G has

decent battery and on a whole is a really good package The LG KM900 Arena introduces new LG UI technology that uses 3D cubes to make the display stunningly beautiful (Buy LG KM900 Arena in India)

Samsung Memoir T929 What strikes most about Samsung Memoir T929 is its sleek and slim design and the fact that it actually looks like a camera It also looks great when you hold it in your hands and use of TouchWiz ensures that you will be using one of the most impressive navigation interfaces that are available among the smartphones Backed by great performance it sure deserves to be among the top five smartphones

There are many other smartphones like Motorola MotoSurf A3100 Palm Pre Pharos Traveler 137 etc that all deserve to be right at the top As for buying one you take your pick and have all the fun you want

QNo 26 Describe Symbian OS Development for mobile or iphone

Ans Symbian OS Development for mobile or iPhone

Features of Symbian Operating System

In Symbian Operating System

Symbian is basically an Operating System consisting libraries UI frameworks and reference implementations of common tools Symbian had been made for mobile devices and smartphones

Under the establishment of non-profit foundation Symbian was acquired by Nokia Symbian OS were also contributed by its user with developing interfaces like S60 UIQ and MOAP(s) To make Symbian royalty-free the process of publishing the source code under EPL (Eclipse Public License) met completion in recent time in 2010

Symbian is being used in more than 45 of the smartphone market which clearly shows how popular Symbian OS is Symbian OS has been powering 330 million phones till date and increasing day by day Although some of the market experts are suggesting an early market entrance to Symbian OS expecting more popularity across the world and the cell phone market

1) Generally the language C++ is used in most of the symbian operating systems But in many Symbian Operating System the operating system can also use languages like Python Visual Basic OPL and Perl

2) Symbian Operating System was built in such a way that it follows the three basic design rules

The integrity and security of user data is of paramount importance

Response time must not be as small as possible

All resources are scarce

3) Symbian OS programming is said to be event-based and the Central Processing Unit is switched off when the running applications and programs are not linked to the event This is achieved through a programming logic called active objects

5) The Symbian Operating system is compatible with all kinds of devices mostly removable media file systems

6) Symbian Operating system 9x which is one of the latest models has adopted a better model

7) The Symbian system is not an Open Source software Cell phone manufacturers though have some parts of its source code

The Symbian applications like the Themes games wall papers and softwarersquos are all SIS files which can also be easily transferred by using Bluetooth or through the internet or through transfer using cables

Features

Location Based Services (LBS)

Location Based Services (LBS) have become almost omnipresent today in all smartphones just like the ubiquitous camera without which a mobile phone is hard to find LBS require smartphones with GPS functionality and are very useful to determine the exact location of self and others in real time

FreeWay

Previously broadband or 3G speeds werent possible on mobile phones but with todays motto of office on the go using your mobile quick net access speeds with easy switching between different networks and connections has become an absolute must FreeWay which is a Symbian IP networking architecture makes this possible and more FreeWay delivers crystal clear and high quality audiovideo streaming VoiP calls robust WiMax and Super 3G experience with its lightening quick download speeds FreeWay can be easily integrated within the existing web browsers thus doing away with the need for additional development

ScreenPlay

ScreenPlay is the powerful new graphics architecture within the Symbian OS meant to deliver high-end graphics that have not been seen previously on any

mobile phone and are life-like and crystal clear ScreenPlay offers big canvass effects on your smartphone and is specially designed for mobile interfaces that integrate HD video with high-detail games and animations ScreenPlay ensures that your visual mobile experience is enhanced manifold while the interface remains simple and versatile ScreenPlay is mean for both intermediate and high-end mobile devices with hardware acceleration Symbian OS ScreenPlay delivers all these benefits without compromising your mobiles battery life in any way

Symmetric Multi-Processing (SMP)

With increasing use of resource gulping applications like high-end games high definition videos GPS services and others Symbian has introduced the SMP technology for its Symbian OS The SMP divides a resource-heavy task among multiple processors on the same chip to finish it quickly and once the task is completed the additional processors fall dormant thus conserving your mobiles battery life A technology to look out for in the near future

Demand Paging

Demand Paging is a technology developed by Symbian for use in its Symbian OS versions 93 onwards which makes more efficient use of the mobiles RAM by selectively loading the data and read-only code only when demanded Previously entire DLLs were copied into the RAM by the Symbian OS whenever required but with Demand Paging only the needed DLL page is copied onto the RAM thus conserving the onboard RAM usage Simply only the code that is currently needed or demanded is loaded into the RAM and not the whole code or page thus it is a more efficient way of utilizing the RAM

Qno 27 Describe Component amp feature of Google Android Apple iPhone Mac OS X Windows Mobile

Ans Google Android

Android is a software stack for mobile devices that includes an operating system middleware and key applications The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language

Features

Application framework enabling reuse and replacement of components Dalvik virtual machine optimized for mobile devices

Integrated browser based on the open source WebKit engine

Optimized graphics powered by a custom 2D graphics library 3D graphics based on the OpenGL ES 10 specification (hardware acceleration optional)

SQLite for structured data storage

Media support for common audio video and still image formats (MPEG4 H264 MP3 AAC AMR JPG PNG GIF)

GSM Telephony (hardware dependent)

Bluetooth EDGE 3G and WiFi (hardware dependent)

Camera GPS compass and accelerometer (hardware dependent)

Rich development environment including a device emulator tools for debugging memory and performance profiling and a plugin for the Eclipse IDE

Android Architecture

The following diagram shows the major components of the Android operating system Each section is described in more detail below

Applications

Android will ship with a set of core applications including an email client SMS program calendar maps browser contacts and others All applications are written using the Java programming language

Application Framework

By providing an open development platform Android offers developers the ability to build extremely rich and innovative applications Developers are free to take advantage of the device hardware access location information run background services set alarms add notifications to the status bar and much much more

Developers have full access to the same framework APIs used by the core applications The application architecture is designed to simplify the reuse of components any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by

the framework) This same mechanism allows components to be replaced by the user

Underlying all applications is a set of services and systems including

A rich and extensible set of Views that can be used to build an application including lists grids text boxes buttons and even an embeddable web browser

Content Providers that enable applications to access data from other applications (such as Contacts) or to share their own data

A Resource Manager providing access to non-code resources such as localized strings graphics and layout files

A Notification Manager that enables all applications to display custom alerts in the status bar

An Activity Manager that manages the lifecycle of applications and provides a common navigation backstack

For more details and a walkthrough of an application see the Notepad Tutorial

Libraries

Android includes a set of CC++ libraries used by various components of the Android system These capabilities are exposed to developers through the Android application framework Some of the core libraries are listed below

System C library - a BSD-derived implementation of the standard C system library (libc) tuned for embedded Linux-based devices

Media Libraries - based on PacketVideos OpenCORE the libraries support playback and recording of many popular audio and video formats as well as static image files including MPEG4 H264 MP3 AAC AMR JPG and PNG

Surface Manager - manages access to the display subsystem and seamlessly composites 2D and 3D graphic layers from multiple applications

LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view

SGL - the underlying 2D graphics engine

3D libraries - an implementation based on OpenGL ES 10 APIs the libraries use either hardware 3D acceleration (where available) or the included highly optimized 3D software rasterizer

FreeType - bitmap and vector font rendering

SQLite - a powerful and lightweight relational database engine available to all applications

Android Runtime

Android includes a set of core libraries that provides most of the functionality available in the core libraries of the Java programming language

Every Android application runs in its own process with its own instance of the Dalvik virtual machine Dalvik has been written so that a device can run multiple VMs efficiently The Dalvik VM executes files in the Dalvik Executable (dex) format which is optimized for minimal memory footprint The VM is register-based and runs classes compiled by a Java language compiler that have been transformed into the dex format by the included dx tool

The Dalvik VM relies on the Linux kernel for underlying functionality such as threading and low-level memory management

Linux Kernel

Android relies on Linux version 26 for core system services such as security memory management process management network stack and driver model The kernel also acts as an abstraction layer between the hardware and the rest of the software stack

The iPhone 4 and its predecessors are more than just fancy cell phones With their range of features ndash from phone to web browser from iPod to mobile game device ndash the iPhone is more like a computer that fits in your pocket and your hand than any cell phone

iPhone Specfications

Physically the iPhone 4 differs a decent amount from the iPhone 3GS and previous models all of which were broadly similar in shape

While the overall presentation of the iPhone 4 is similar to its predecessors its different in that its no longer tapered on the edges includes a glass face on the front and back wraps the antenna around the outside of the phone (which has caused antenna some problems) and is slightly thinner

All iPhones offer a 35-inch touchscreen that employs multi-touch technology Multi-touch allows users to control items on the screen with more than one finger simultaneously (thus the name) Itrsquos multi-touch that enables some of the iPhonersquos most famous features such as tapping the screen twice to zoom in or ldquopinchingrdquo and dragging your fingers to zoom out

Other major differences between the iPhone 4 and earlier models include use of the Apple A4 processor the inclusion of two cameras a high-resolution screen and improved battery life

Both phones use a trio of sensors to produce some of their best usability features though neither model offers expandable or upgradeable memory

iPhone Features

Because the iPhone is like a mini-computer it offers the same wide range of features and functions that a computer does The major areas of function for the iPhone are

Phone ndash The iPhonersquos phone features are solid It includes innovative features like Visual Voicemail and standard features like text messaging and voice dialing

Web browsing ndash The iPhone offers the best most complete mobile browsing experience Though it doesnrsquot support the standard Flash browser plug in it doesnrsquot require dumbed-down ldquomobilerdquo versions of websites instead offering the real thing on a phone

Email ndash Like all good smartphones the iPhone has robust email features and can sync to corporate email servers running Exchange

CalendarPDA ndash The iPhone is a personal information manager too with calendar address book stock-tracking weather update and related features

iPod ndash A shortcut description of an iPhone is a combined cell phone and iPod so of course its music player features offer all the advantages and coolness of iPods

Video playback ndash With its big beautiful 35-inch screen the iPhone is a great choice for mobile video playback whether using the built-in YouTube application adding your own video or buying or renting content from the iTunes Store

Apps ndash With the addition of the App Store iPhones can now run all kinds of third-party programs from games (both free and paid) to Facebook and Twitter to restaurant finders and productivity apps The App Store makes the iPhone the most useful smartphone around

Cameras - One major change in the iPhone is the inclusion of two camera whereas previous models only had one The camera on the back of the phone shoots 5-megapxzel still images and takes 720p HD video The user-facing camera allows FaceTime video chatsiPhone Home Screen

With the release of iPhone firmware ndash the software that runs the phone - version 113 users can re-arrange the icons on their home screen This is especially helpful once you start adding programs from the App Store as you can group similar applications or the ones you use the most often together Of course being able to re-arrange icons also leads to some unexpected events like all the icons on your screen shaking

iPhone Controls

Though the iPhonersquos coolest control features are based around the multi-touch screen it also has a number of buttons on its face that are used for control

Home button ndash This button at the bottom of the phone right below the screen is used to wake the phone from sleep and control some onscreen features

Hold button ndash At the top right corner of the iPhone yoursquoll find the hold button Pressing this button locks the screen andor puts the phone to sleep Itrsquos also the button used to restart the phone

Volume button ndash On the left side of the phone a long button that moves up and down controls the volume of music video and the phonersquos ringer

Ringer button ndash Just above the volume control is a smaller rectangular button This is the ringer button which allows you to put the phone into silent mode so the ringer wonrsquot sound when calls come in

Dock Connector ndash This port at the bottom of the phone is where you plug in the cable to sync the phone with a computer as well as accessories

Using iPhone with iTunes

Like an iPod the iPhone is synced with and managed using iTunes

Activation - When you first get an iPhone you activate it through iTunes and select your monthly phone plan using the software

Sync - Once the phone is activated iTunes is used to sync music videos calendars and other information to the phone

Restore and Reset ndash Lastly iTunes is also used to reset data on the iPhone and restore contents from backup if problems cause you to need to erase the contents of the phone

energy If mounted on the roof of a car the length of λ4 is efficient This is also known as Marconi antenna

A λ2 dipole has a uniform or omni-directional radiation pattern in one plane and a figure eight pattern in the other two planes This type of antenna can only overcome environmental challenges by boosting the power level of the signal Challenges could be mountains valleys buildings etc

Q2 What are the main problems of signal propagation Why do radio waves not always follow a straight line Why is reflection both useful amp harmful

Ans

In wireless networks the signal has no wire to determine the direction of propagation whereas signals in wired networks only travel along the wire (which can be twisted pair copper wires a coax cable but also a fiber etc) As long as the wire is not interrupted or damaged it typically exhibits the same characteristics at each point One can precisely determine the behavior of a signal travelling along






















Ans















Ans


























home network



















common COA















the router anyway









with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls

































Ans















Ans


























home network



















common COA















the router anyway









with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls

























Ans


























home network



















common COA















the router anyway









with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls




































home network



















common COA















the router anyway









with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls
















common COA















the router anyway









with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls


















with this solution







IP packet delivery





















1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls

























1G- FDMA

2G- FDMA TDMA


3G- CDMA2000WCDMA



2 Wireless LAN

3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls












3 Wireless MAN

4 WirelessWAN




































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls








































Soluiton16














types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls

















types of channels


carry the



determine

handoffs


system











handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls


















handoffs














cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls


















cells



compared to TDMA


signals



degrade







various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls
















various codes


spread over a




need for




technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls














technology



chip





can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls













can own









ANS


GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls













GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

GSM at 96 Kbps


576 Kbps


by mid-2001

EDGE up to 384 Kbps


GSM at 96 Kbps


576 Kbps



by mid-2001

EDGE up to 384 Kbps


2G

25G

3G

2G SYSTEMS









DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls














DRAWBACKS OF 2G












ndash IS-95 IS-95b




Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls














Goals of 3G Systems

More services

Web browsing

VoD

Video phone call

Mobile computation

Improved quality




More flexible





2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls












2G EVOLUTION TO 3G





systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls















systems are [1]



the 3G systems











Internet co


















4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls





























4G







Frequency Band






Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls













Access Technologies

W-CDMA 1xRTT Edge





Component Design




All IP (IP60)














Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls






















Applications






Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls
















Technologies

















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls




















































































Features



FreeWay


ScreenPlay





Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls















Demand Paging



Ans Google Android


Features












Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls






















Applications













Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls




















Libraries










Android Runtime




Linux Kernel









iPhone Features











iPhone Controls

















Android Runtime




Linux Kernel









iPhone Features











iPhone Controls


















iPhone Features











iPhone Controls

















iPhone Controls












Mobile Assignment I

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Transcript of Mobile Assignment I