Sr. Topic Remarks

1Introduction mobile computing environment and to study the mobile computing environment

2 To study the various modern wireless communication technologies available

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To Study The Different Types Of Technologies, Type Of Services, Commercial Names Of Service Providers And Equipment Manufacturers Of Mobile Services.

4 to study how a call flow sequence takes place in a mobile phone

5 To study the mobile database system in wireless networks

6 To study cache management in mobile network.

7 To study the components of cell phone.

8 To GSM architecture in cellular system

Index

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EXPERIMENT NO. 1

AIM: Introduction mobile computing environment and to study the mobile computing environment

INTRODUCTION

Mobile Computing: A technology that allows transmission of data, via a computer, without having to be connected to a fixed physical link.

Mobile voice communication is widely established throughout the world and has had a very rapid increase in the number of subscribers to the various cellular networks over the last few years. An extension of this technology is the ability to send and receive data across these cellular networks. This is the principle of mobile computing.

Mobile data communication has become a very important and rapidly evolving technology as it allows users to transmit data from remote locations to other remote or fixed locations. This proves to be the solution to the biggest problem of business people on the move - mobility.

EXISTING CELLULAR NETWORK ARCHITECTURE

Mobile telephony took off with the introduction of cellular technology, which allowed the efficient utilization of frequencies enabling the connection of a large number of users.

A cellular network consists of mobile units linked together to switching equipment, which interconnect the different parts of the network and allow access to the fixed Public Switched Telephone Network (PSTN). The technology is hidden from view; it's incorporated in a number of transceivers called Base Stations (BS). Every BS is located at a strategically selected place and covers a given area or cell - hence the name cellular communications. A number of adjacent cells grouped together form an area and the corresponding BSs communicate through a so-called Mobile Switching Centre (MSC). The MSC is the heart of a cellular radio system. It is responsible for routing, or switching, calls from the originator to the destinator. It can be thought of as managing the cell, being responsible for set-up, routing control and termination of the call, for management of inter-MSC hand over and supplementary services, and for collecting charging and accounting information. The MSC may be connected to other MSCs on the same network or to the PSTN.

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Fig. Mobile Switching Centre

The frequencies used vary according to the cellular network technology implemented. For GSM, 890 - 915 MHz range is used for transmission and 935 -960 MHz for reception. The DCS technology uses frequencies in the 1800MHz range while PCS in the 1900MHz range.

Each cell has a number of channels associated with it. These are assigned to subscribers on demand. When a Mobile Station (MS) becomes 'active' it registers with the nearest BS. The corresponding MSC stores the information about that MS and its position. This information is used to direct incoming calls to the MS.

If during a call the MS moves to an adjacent cell then a change of frequency will necessarily occur - since adjacent cells never use the same channels. This procedure is called hand over and is the key to Mobile communications. As the MS is approaching the edge of a cell, the BS monitors the decrease in signal power. The strength of the signal is compared with adjacent cells and the call is handed over to the cell with the strongest signal.

During the switch, the line is lost for about 400ms. When the MS is going from one area to another it registers itself to the new MSC. Its location information is updated, thus allowing MSs to be used outside their 'home' areas.

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PSTN

MSC MSC

MSC

Other MSCsOther MSCs

Base station

Data communication:

Data Communications is the exchange of data using existing communication networks. The term data covers a wide range of applications including File Transfer (FT), interconnection between Wide-Area-Networks (WAN), facsimile (fax), electronic mail, access to the internet and the World Wide Web (WWW).

Fig. Data communication overview

MOBILITY ENVIRONMENT ARCHITECTURE

To overcome restrictions in mobile computing the above architecture was designed; the architecture consists of the following parts: The network environment consists of mobile hosts fixed hosts and certain access points. The fixed hosts are all connected to a backbone (i.e. the Internet). Mobile

hosts usually do not contact them directly, but use physically closer located hosts as access points to the backbone for means of minimizing the distance that has to be bridged by a mobile connection line. In addition to the users carrying a portable computer with them, also mobile users traveling between fixed hosts are considered in our system.

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Fig. Mobility environment

To distinguish from conventional client-server and network tunneling systems we chose the notions frontend for a mobile host, backend for a fixed host that is servicing mobile nodes and relay for an access point to the backbone. The system can be modeled using the familiar client-server notion when full connectivity is guaranteed. However, when dealing with weak and sometimes fully broken lines, traditional client-server terms are not sufficient any more to model the system. E.g. in the case of full disconnection the frontend will simulate the connection to the server using cached data. Similarly, a relay in our system provides more functionality than a convenient gateway does. It offers important services for mobile hosts, especially an elaborate authentication and authorization service which is of special importance for a secure mobile system.

APPLICATIONS OF MOBILE COMPUTING:

We identify categories of applications a mobile user is most likely to execute on his mobile device. Due to the existing limitations of portable devices (limited computational power, disk space, screen size, etc.), we claim that portable devices should not be considered general-purpose computers. For example, we do not expect a user to run complex simulations or compile and link huge software systems on these devices. Even though portable devices will become increasingly powerful, they will never match the computational power and facilities available on typical desktop machines. Similarly, while the wireless technology will improve, providing more and more bandwidth to the end user, wired network technology will advance as well, with the result that wireless networks will remain, in the near to medium future, orders of magnitudes slower. Therefore, mobile computing will always be characterized by a scarcity of resources, relatively speaking. In our opinion, an end-user will

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execute applications in one of the following five categories in such an environment:

Standalone applications such as games or utilities; Personal productivity software (word processors, presentation software, calendars); Internet applications such as e-mail, WWW browsers, multi-user calendars, or telnet; New "location-aware" applications: tour planners, interactive guides; Ad-hoc network and groupware applications.

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EXPERIMENT NO. 2

AIM: - To study the various modern wireless communication technologies available

INTODUCTION

Wireless communications is one of the most active areas of technology development of our time. This development is being driven primarily by the transformation of what has been largely a medium for supporting voice telephony into a medium for supporting other services, such as the transmission of video, images, text, and data. Wireless communications today covers a very wide array of applications. The cellular telephony is very important driver of wireless technology development, and in recent years the push to develop new mobile data services, which go collectively under the name third-generation (3G) cellular, has played a key role in motivating research in new signal processing techniques for wireless. However, cellular telephony is only one of a very wide array of wireless technologies that are being developed very rapidly at the present time.

Following are the five modern wireless communication technologies:

Wi-Fi, Bluetooth, RFID, WLAN, WMAN

1. Wi-Fi: Wireless Fidelity

WiFi is the wireless way to handle networking. It is also known as 802.11 networking and wireless networking. The big advantage of WiFi is its simplicity. You can connect computers anywhere in your home or office without the need for wires. The computers connect to the network using radio signals, and computers can be up to 100 feet or so apart.

Wi-Fi networks use radio technologies called IEEE802.11b, 802.11a or 802.11g to provide wireless connectivity in local area networks. A Wi-Fi network can be used to connect computers to each other, to the Internet, and to wire networks using IEEE 802.3 or Ethernet.

Wi-Fi gets to connect to the Internet in the office, airport, hotel, business-center, congress-hall, trade center, cafe, restaurant and other public places. Based on this technology any employee or visitor gets mobile Internet access without losing freedom of movement across the hotspot. A hotspot is a connection point for a WiFi network. A small box is hardwired into the Internet. The box contains an 802.11 radio that can simultaneously talk to up to 100 or so 802.11 cards. There are many WiFi hotspots now available in public places like restaurants, hotels, libraries and airports.

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Fig. Wireless fidelity

The Hot Spot

The Access Points are installed in the building in order to provide a high-speed Wi-Fi technology based Internet access. The 1-Point coverage zone - "Hot-Spot" can achieve 200 m. in a radius, which in most cases is sufficient to evenly reach all parts of a building. However, it should also be noted, that the feasible areas might vary depending on the number and nature of the obstacles (walls, metallic structures).

All Access Points in the building are combined into a central router, which is connected to the Internet.

2. Blue-tooth

Bluetooth is an industrial specification for wireless personal area networks (PANs). Bluetooth provides a way to connect and exchange information

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between devices such as mobile phones, laptops, PCs, printers, digital cameras and video game consoles over a secure, globally unlicensed short-range radio frequency. The Bluetooth specifications are developed and licensed by the Bluetooth Special Interest Group.

A short-range radio technology aimed at simplifying communications among Internet devices and between devices and the Internet. It also aims to simplify data synchronization between Internet devices and other computers.

Fig: Typical Bluetooth mobile phone Hands-free

Bluetooth is a radio standard and communications protocol primarily designed for low power consumption, with a short range (power-class-dependent: 1 meter, 10 meters, 100 meters) based on low-cost transceiver microchips in each device.

Bluetooth lets these devices communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, so long as the received transmission is powerful enough.

In order to use Bluetooth, a device must be compatible with certain Bluetooth profiles. These define the possible applications and uses.

Briefly, Bluetooth technology,

uses radio waves in 2.4 GHz band - therefore, no line of sight is required

supports multipoint, not just point to point  works in a small confined area - 10 to 15 meters apart is able to support speeds of 1-2 Mbps today but will offer higher speeds

in future has significant industry support with over 1800 members in the industry

consortium

List of applications

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Wireless control of and communication between a cell phone and a hands-free headset or car kit. This was one of the earliest applications to become popular.

Wireless networking between PCs in a confined space and where little bandwidth is required.

Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer.

Transfer of files between devices with OBEX. Transfer of contact details, calendar appointments, and reminders

between devices with OBEX. Replacement of traditional wired serial communications in test

equipment, GPS receivers, and medical equipment and traffic control devices.

For controls where infrared was traditionally used. Sending small advertisements from Bluetooth enabled advertising

hoardings to other, discoverable, Bluetooth devices. Wireless control of a games console—Nintendo Wii and Sony

PlayStation 3 both use Bluetooth technology for their wireless controllers.

3. RFID: Radio Frequency Identification

Short for radio frequency identification, a technology similar in theory to bar code identification. With RFID, the electromagnetic or electrostatic coupling in the RF portion of the electromagnetic spectrum is used to transmit signals. An RFID system consists of an antenna and a transceiver, which read the radio frequency and transfer the information to a processing device, and a transponder, or tag, which is an integrated circuit containing the RF circuitry and information to be transmitted.

RFID systems can be used just about anywhere, from clothing tags to missiles to pet tags to food -- anywhere that a unique identification system is needed. The tag can carry information as simple as a pet owners name and address or the cleaning instruction on a sweater to as complex as instructions on how to assemble a car. Some auto manufacturers use RFID systems to move cars through an assembly line. At each successive stage of production, the RFID tag tells the computers what the next step of automated assembly is.

One of the key differences between RFID and bar code technology is RFID eliminates the need for line-of-sight reading that bar coding depends on. Also, RFID scanning can be done at greater distances than bar code scanning. High frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer transmission ranges of more than 90 feet, although wavelengths in the 2.4 GHz range are absorbed by water (the human body) and therefore has limitations.

RFID is also called dedicated short range communication (DSRC).

4. WLAN: Wireless LAN

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Wireless LAN is simply trying to imitate the structure of the wired LANs, using another medium to transfer data rather than cables. This medium is electromagnetic waves, which are mainly either radio frequency (RF) or infrared frequency (IR).

Wireless LANs consist mainly of two entities: clients or end-user devices and Access Points (AP). Clients' are equipped with devices that allow the user to use the RF medium to communicate with other wireless devices. AP functions like a regular switch or router in wired network for the wireless devices. Moreover, it represents a gateway between the wireless devices and a wired network.

Fig. Wireless LAN

The basic structure of a Wireless LAN is called BSS (Basic Service Set), in which the network consists of an AP and several wireless devices. When these devices try to communicate among themselves they propagate their data through the AP device. In order to form the network, AP keeps broadcasting its SSID (Service Set Identifier) to allow others to join the network.

Fig. WLAN: BSS Structure

5. WMAN : Wireless MAN

The idea behind using WMAN is to offer a broadband Internet service using wireless infrastructure. The idea is very similar to a TV broadcast network (shown in Fig.10). The theoretical speed of WMAN is 75Mbps extended to several miles, which offer a replacement to cable and DSL connections in the future.

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WMAN is also called BWA (Broadband Wireless Access) as a formal title along with the industry icon acronym WiMAX. The main target of implementing WiMAX technology is to provide a convenient solution to the "last mile access", where the fast data backbone traffic is to be distributed among consumers. This also helps expand the Internet covered areas especially in rural areas.

Fig. Wireless MAN

WiMAX (Worldwide Interoperability for Microwave Access) is a wireless industry coalition whose members organized to advance IEEE 802.16 standards for broadband wireless access (BWA) networks. WiMAX 802.16 technology is expected to enable multimedia applications with wireless connections. WiMax also has a range of up to 30 miles, presenting provider networks with a viable wireless last mile solution.

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EXPERIMENT- 3

AIM: To Study The Different Types Of Technologies, Type Of Services, Commercial Names Of Service Providers And Equipment Manufacturers Of Mobile Services.

The first radiotelephone service was introduced in the US at the end of the 1940s, and was meant to connect mobile users in cars to the public fixed network. In the 1960s, a new system launched by Bell Systems, called Improved Mobile Telephone Service" (IMTS), brought many improvements like direct dialing and higher bandwidth. The first analog cellular systems were based on IMTS and developed in the late 1960s and early 1970s. The systems were "cellular" because coverage areas were split into smaller areas or "cells", each of which is served by a low power transmitter and receiver.

First generation:- 1G analog system for mobile communications saw two key improvements during the 1970s: the invention of the microprocessor and the digitization of the control link between the mobile phone and the cell site. AMPS (Advance mobile phone system) was first launched by US which is 1G mobile system. It is best on FDMA technology which allows users to make voice calls within one country.

Second generation:- 2G digital cellular systems were first developed at the end of the 1980s. These systems digitized not only the control link but also the voice signal. The new system provided better quality and higher capacity at lower cost to consumers. GSM (Global system for mobile communication) was the first commercially operated digital cellular system which is based on TDMA.

Third generation:- 3G systems promise faster communications services, including voice, fax and Internet, anytime and anywhere with seamless global roaming. ITU’s IMT-2000 global standard for 3G has opened the way to enabling innovative applications and services (e.g. multimedia entertainment, infotainment and location-based services, among others). The first 3G network was deployed in Japan in 2001. 2.5G networks, such as GPRS (Global Packet Radio Service) are already available in some parts of Europe. 3G technology supports 144 Kbps bandwidth, with high speed movement (e.g. vehicles), 384 Kbps (e.g. on campus) & 2 Mbps for stationary (e.g.inbuilding )

Fourth generation:- At present the download speed for mode data is limited to 9.6 kbit/sec which is about 6 times slower than an ISDN (Integrated services digital network) fixed line connection. Recently, with 504i handsets the download data rate was increased 3-fold to 28.8kbps. However, in actual use the data rates are usually slower, especially in crowded areas, or when the network is "congested". For third generation mobile (3G, FOMA) data rates are 384 kbps (download) maximum, typically around 200kbps, and 64kbps upload since

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spring 2001. Fourth generation (4G) mobile communications will have higher data transmission rates than 3G. 4G mobile data transmission rates are planned to be up to 20 megabits per second.

Before understanding 4G, we must know what is 3G? 3G initiative came from device manufactures, not from operators. In 1996 the development was initiated by Nippon Telephone & Telegraph (NTT) and Ericsson; in 1997 the Telecommunications Industry Association (TIA) in the USA chose CDMA as a technology for 3G; in 1998 the European Telecommunications Standards Institute (ETSI) did the same thing; and finally, in 1998 wideband CDMA (W-CDMA) and cdma2000 were adopted for the Universal Mobile Telecommunications System (UMTS).

W-CDMA and CDMA 2000 are two major proposals for 3G. In this CDMA the information bearing signal is multiplied with another faster ate, wider bandwidth digital signal that may carry a unique orthogonal code. W-CDMA uses dedicated time division multiplexing (TDM) whereby channel estimation information is collected from another signal stream. CDMA 2000 uses common code division multiplexing (CDM) whereby channel estimation information can be collected with the signal stream.

Access Technologies (FDMA, TDMA, CDMA) - FDMA: Frequency Division Multiple Access (FDMA) is the most common analog system. It is a technique whereby spectrum is divided up into frequencies and then assigned to users. With FDMA, only one subscriber at any given time is assigned to a channel. The channel therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a different channel. A "full-duplex" FDMA transmission requires two channels, one for transmitting and the other for receiving. FDMA has been used for first generation analog systems.

TDMA: Time Division Multiple Access (TDMA) improves spectrum capacity by splitting each frequency into time slots. TDMA allows each user to access the entire radio frequency channel for the short period of a call. Other users share this same frequency channel at different time slots. The base station continually switches from user to user on the channel. TDMA is the dominant technology for the second generation mobile cellular networks.

CDMA: Code Division Multiple Access is based on "spread" spectrum technology. Since it is suitable for encrypted transmissions, it has long been used for military purposes. CDMA increases spectrum capacity by allowing all users to occupy all channels at the same time. Transmissions are spread over the whole radio band, and each voice or data call are assigned a unique code to differentiate from the other calls carried over the same spectrum. CDMA allows for a “soft hand-off”, which means that terminals can communicate with several base stations at the same time.

Beyond 3G

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In the field of mobile communication services, the 4G mobile services are the advanced version of the 3G mobile communication services. The 4G mobile communication services are expected to provide broadband, large capacity, high speed data transmission, providing users with high quality color video images, 3D graphic animation games, audio services in 5.1 channels. We have been researching the vision of 4G mobile communication systems, services, and architectures. We also have been developing the terminal protocol technology for high capacity, high speed packet services, public software platform technology that enables downloading application programs, multimode radio access platform technology, and high quality media coding technology over mobile networks.

Reasons To Have 4G - 1.Support interactive multimedia services: teleconferencing, wireless Internet, etc. 2.Wider bandwidths, higher bit rates. 3.Global mobility and service portability. 4.Low cost. 5.Scalability of mobile networks.

MOBILE PHONE OPERATORS:

Rank Operator Technology Ownership

1 Airtel GSM, EDGE Bharti Tele-Ventures, Singapore Telecommunications (30.84%) and Vodafone (10%)

2 RIM GSM, CDMA Reliance Communications Limited

3 BSNL GSM State-owned

4 Hutch GSM, EDGE Hutchison Whampoa & Essar Group

5 !DEA GSM Aditya Birla Group

6 TATA MOBILE

GSM, CDMA Tata Group

7 Aircel GSM Maxis Telecom

8 BPL MOBILE GSM, GPRS Essar Group

9 Fascel GSM Hutchison Whampoa & Essar Group, HFCL and Kotak Mahindra

10 Spice GSM Spicecorp and DISTACOM

11 MTNL GSM State-owned

Cell Phone Manufacturers:

Apple Inc. joined the cellular phone world in 2007 with the introduction of the iPhone.

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On October 1st 2005, BenQ Corporation acquired Siemens' mobile phone business and created BenQ Mobile.

Research In Motion (RIM) is a world leader in the mobile communications market and has a history of developing breakthrough wireless solutions.

Ericsson in one of the largest supplier of mobile systems in the world and support all major standards for wireless communication.

The cell phone manufacturer i-mate prides themselves on continuing to develop high-end wireless integrated pocket PCs and Smartphones.

Headquartered in San Diego, California, LG is the North American wireless division of LGE, a business unit of LG Electronics (LGE)

Motorola is a global leader in wireless, automotive and broadband communications.  Motorola's Intelligence Everywhere.

The roots of Nokia go back to the year 1865 with the establishment of a forest industry enterprise in South-Western Finland by mining engineer.

O2 is a UK mobile telephony company.  It was formerly British Wireless and then the BT Group's mobile telephony division.

Panasonic, a creator of numerous electronic devices including wireless handsets, have a corporate attitude that puts the consumer first.

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Sagem Communication is a subsidiary of the SAFRAN Group.  Sagem brand name can be found on numerous devices which include mobile phones, modules

In 1996, Samsung Electronics' Telecommunication Network Division became the first in the world to utilize commercialized CDMA services.

Siemens supplies mobile infrastructure for 180 customers in more than 90 countries, making them one of the top three providers worldwide.

Sony Ericsson Mobile Communications offers mobile multimedia consumer products for people who appreciate the possibilities of powerful technology.

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EXPERIMENT NO. 4

AIM: - to study how a call flow sequence takes place in a mobile phone

Accessing a GSM network

In order to gain access to GSM services, a user needs three things:

A subscription with a mobile phone operator. This is usually either a Pay As You Go arrangement, where all GSM services are paid for in advance, or a Pay Monthly option where a bill is issued each month for line rental, normally paid for a month in advance, and for services used in the previous month.

A mobile phone which is GSM compliant and operates at the same frequency as the operator.

A SIM card which is issued by the operator once the subscription is granted. The card comes pre-programmed with the subscriber's phone "identity" and will be used to store personal.

After subscribers sign up, information about their phone's identity and what services they are allowed to access are stored in a "SIM record" in the Home Location Register (HLR). The Home Location Register is a database maintained by the "home" phone company for all of its subscribers. It is used to answer queries like, "Where on the mobile phone network is the device associated with this phone number?" and "What services is this subscriber paying for?”

Once the SIM card is loaded into the phone and it is powered on, it will search for the nearest mobile phone mast, also called a Base Transceiver Station or BTS. If a mast can be successfully contacted, then there is said to be coverage in the area.

As the SIM card is loaded into the phone and it is powered on, it will search for the nearest mobile phone mast, also called a Base Transceiver Station or BTS. If a mast can be successfully contacted, then there is said to be coverage in the Register.

The Visitors LR will tell the Home LR where the phone is connected to the network (which VLR), and will ask it for a copy of the SIM record (which includes, for example, what services the phone is allowed to access). The current cellular location of the phone (i.e. which BTS it is at) is entered into the VLR record and will be used during a process called paging when the GSM network wishes to locate the mobile phone.

How outgoing calls are made from a mobile

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Once a mobile phone has successfully attached to a GSM network as described above, calls may be made from the phone to any other phone on the global Public Switched Telephone Network assuming the subscriber has an arrangement with their "home" phone company to allow the call.

The user dials the telephone number, presses the send or talk key, and the mobile phone sends a call setup request message to the mobile phone network via the mobile phone mast (BTS) it is in contact with.

The element in the mobile phone network that handles the call request is the Visited Mobile Switching Center (Visited MSC). The MSC will check against the subscriber's temporary record held in the Visitor Location Register to see if the outgoing call is allowed. If so, the MSC then routes the call in the same way that a telephone exchange does in a fixed network.

If the subscriber is on a Pay As You Go tariff, then an additional check is made to see if the subscriber has enough credit to proceed. If not, the call is rejected. If the call is allowed to continue, then it is continually monitored and the appropriate amount is decremented from the subscriber's account. When the credit reaches zero, the call is cut off by the network. The systems that monitor and provide the prepaid services are not part of the GSM standard services, but instead an example of intelligent network services that a mobile phone operator may decide to implement in addition to the standard GSM ones.

How incoming calls are made to a mobile

As soon as the owner switches on his mobile phone, it registers with the network provider via the nearest base station. At the network provider, data on the identity of the user, the serial number of the mobile phone and the identity of the base station over which registration has occurred is logged and stored. This is done even if no conversation takes place. Moreover, every time a number is dialed, this event is stored, irrespective of whether a connection is established or not. This takes place in three steps.

I. CALL ORIGINATION OPERATION

II. CALL DELIVERY OPERATIONIII. CALL TERMINATION

OPERATION

I. CALL ORIGINATION OPERATION

1. Mobile station sends the call origination request to MSC 2. MSC forwards the request to VLR to check the user information.

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3. VLR checks the users profile and ask MSC to grant call request. 4. MSC sets up trunk access to std. PSTN call setup.

II. CALL DELIVERY OPERATION

1. Call from the source reaches to the PSTN 2. PSTN forwards the call to the home MSC of the target mobile. 3. MSC gets the routing information about the target mobile from HLR 4. HLR in turn passes request to VLR 5. VLR sends the routing information to HLR 6. HLR passes this information to MSC 7. MSC when have got this routing information routes the call to the MSC1 8. MSC which is the present location of the target mobile passes the call to the destination mobile.

III. CALL TERMINATION OPERATION

1. The calling subscriber dials the mobile subscriber.2. The mobile network prefix digits cause the call to be routed to the mobile network gateway MSC.3. The gateway MSC uses information in the called address digits to locate the mobile subscribers HLR.4. The HLR has already been informed of the location (VLR address) for the mobile subscriber and requests a temporary routing number to allow the call to be routed to the correct MSC.5. The MSC/VLR responds with a temporary routing number that will be valid only for the duration of this call.6. The routing number is returned to the GMSC (gateway MSC).7. The call is made using standard ISUP (or similar) signaling between the GMSC and the visited MSC.

Fig. Mobile terminated call

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EXPERIMENT NO. 5

AIM: To study the mobile database system in wireless networks

The data for the mobile networks is stored on the servers. The data items are aggregated to form pages and these pages are then aggregated to form disks and these disks are stored at the servers. The operations performed on the server to maintain the consistency and the ease of access of data are indexing and caching. Figure 1 below presents a general architecture of the mobile database system.

Figure 1: Architecture of Mobile Database System

System architecture model

Architecture model consists of stationary and mobile components. Mobile component is the mobile client, which can connect fixed network via a wireless link. Stationary components could be fixed host or base stations. Fixed Host in a fixed network does not have capable of connecting to a mobile unit. Base stations are augmented with wireless interface to communicate with mobile computers, called Mobile Support Station (MSS). In the above architecture model, database servers residing on fixed host and MSS compose a distributed database system. As a part of the distributed database system, each MSS can also function as a mobile transaction coordinator, which receives transaction operations from mobile clients and coordinates their execution. A mobile client can move arbitrarily at any moment within a wireless cell or among different cells. When it is connected with the fixed network, it always communicates with the MSS supporting the cell where it is currently located. In addition, it can disconnect from the fixed network at any

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time. When it reconnects with the fixed network, it fetches back the results of previous operations and sends subsequent operations.

An important property of the data items in a mobile computing system is that their values can be highly dynamic and sensitive as they are used to maintain the useful information such as weather, highway conditions, traffic directions, news, stock quotes and the location of a moving object. To maintain the freshness and validity of the data items, data items should be updated often by the generation of update transactions. It is assumed that the updates are generated by means of some external environment such as capture devices, and sensors. The broadcast server disseminates all the data items periodically in each broadcast cycle. The duration of a broadcast cycle may be fixed or variable depending on the adopted broadcast scheduling algorithm, which is also used for selecting data items to broadcast.

Update transactions consist of one to several write operations and its arrival rate can be very high. It is assumed that a well-formed concurrency control protocol, such as two phase-locking, is used for concurrency control amongst the update transactions at the database server. Mobile clients issue mobile transactions to access data items at the database. It is assumed that each mobile transaction consists of a sequence of read operations and defined with a deadline. In the model, the broadcast process is modeled as a long read-only transaction, called broadcast transaction. The length of a broadcast transaction is defined based on the life span of a mobile transaction that is equal to the time required to broadcast its data items. Thus, the data item set of a broadcast transaction includes all the data items, which are broadcast during the period from (current time - life-span of a mobile transaction) to current time.

Correctness of transactions in broadcast environments

Dissemination of data items to mobile transactions may be performed concurrently with the execution of update transactions. So it is possible that mobile transactions may read inconsistent data values due to uncontrolled interleaving of update and mobile transactions. Moreover, Mobile transaction should access updated value of data items. Thus, there are two fundamental requirements for disseminating data items to mobile transactions: Mutual consistency and Currency. Mutual consistency ensures that (a) the server maintains mutually consistent data and (b) clients can read mutually consistent data. Currency ensures that clients can access data that is current.

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EXPERIMENT NO. 7

AIM: To study the components of cell phone.

Component Purpose Microphone:- Captures your voice for

conversion from analogue to digital mode

Speaker:- Allows monitoring of remote phone

LCD Display:- Shows Call, Phone, Signal & Network Info

Keypad:- Allows access to specific remote phones

Battery + Meter:- While battery housings on cellphones are standard

input deigns, some cellphones also have some "battery processing"

intelligence built in. For example, they will check the charge level to

start or stop the charge when the phone is connected to a desktop,

car or quick charger and even automatically discharge the battery for

you when necessary. This is usually linked to the LCD display and to

an audible beep to warn you of the battery charge status.\

LED Lights:- Status Information, usually Green, white & Red.

Digital Signal Processor:- The DSP chipset is a critical component.

It co-ordinates the voice, SMS and data/fax features of a cell phone.

It processes speech, handles voice activity detection, as well as

discontinuous GSM transmission and reception. Another section

amplifies the input signal received from the microphone, while

another converts this microphone voice signal from "analogue" to

"digital". The digital conversion is necessary because the GSM

cellular standard is a completely digital system.

CODEC:- This DSP's voice processing is done in tandem with highly

sophisticated compression technique mediated by the "CODEC"

(compressor/decompression) portion of the cell phone.

TRF Unit:- The CODEC chipset instantly transfers this "compressed"

information to the cell phone’s Radio Frequency (RF) unit. This RF

unit, which is essentially the transmit and receive section of the cell

phone, then sends out the voice or data information via the cell phone

antenna, over the air and on to the nearest cellular base station - and

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ultimately to your call destination. The incoming voice also travels

much the same route, although it is first uncompressed from it’s

incoming digital form into an audible analogue form which is then

piped out as sound through the cell phone’s speaker. This analogue-

to-digital and digital-to-analogue voice conversion via the CODEC is

done at very high speeds, so that you never really experience any

delay between talking and the other person hearing you (and visa

versa).

SIM Card Reader:- When you switch on your phone with a "live" SIM

card inside, the subscriber information on the chip inside the SIM

card is read by the SIM card reader and then transmitted digitally to

the network via the RF unit. The same route is followed when you hit

the Call button (and it’s variants) on the cell phone: the number

you’ve inputted is instantly and digitally transferred to the network for

processing.

External Connectors At the bottom of most cellphones there is an

external connector system. You can usually plug in a data/fax

adapter, or a battery charger, or a personal hands free device, or a

car-kit with external antenna connections. You’ll also find many with

separate "speaker" and LED lights that are activated when the phone

rings and/or when the battery is low. Many phones also have tiny

LED lights under the keypad that light up when you press a key

and/or when the phone rings.

On-Board Memory:- Many cellphones also have a certain amount of

on-board memory chip capacity available for storing outgoing

telephone numbers, your own telephone number, as well as incoming

and outgoing SMS messages. Some allow copying between the

(limited) memory on the SIM card and the phone’s own nternal

memory.

Antenna System: Cellphone manufacturers are implementing many

weird and wonderful permutations of antenna system designs. While

some are stubby, fixed types, the most predominant designs though

are those with thin, pull-out steel rods all of whom usually fit snugly

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into a special antenna shaft. These antenna designs, be they the

stubby or pull-out types, all conform to the same circa 900 MHz

frequency transmit and receive range required by the GSM

specification.

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Select an area inside this demo cellphone design:

SIM Reader

RF Unit

CODEC

DSP

Memory

LCD and key pad

Speaker

keypad

mic

antenna

battery

connector

SINGLE BOARD DUAL-BAND HANDSET REFERENCE DESIGN FOR GSM900 & GSM1800

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s

User Interface:

Foreign language fonts, incl. Chinese

· Flexible Phone book

  - Store numbers in phone (ME)

  - SIM Abbreviated Number Phone Book

  - SIM Fixed Number Dialing

· Stores last 10 numbers called & received

· Generate DTMF tones during call

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· Speaker/sidetone/mic amplification control

· Visual indication of remaining battery life

· Integrated data and fax adapters

Software & Services :· Full Rate/Enhanced Full Rate Speech with DTX

· Short Message Services (SMS)

· A5/1 and A5/2 encryption

· Group 3 fax & Ph. 2 Supplemental services

· GSM data service

  -Full rate 9.6, 4.8, 2.4 Kbps

  -Half rate 4.8, 2.4 Kbps

· Hardware support for Phase 2+ data service:

  -14.4 Kbps data service

· Layers 2/3 & MMI software supplied

  -Type Approved GSM Phase 2    protocol stack

The MTI-1400 :

Reference Design is a breakthrough in design compactness,

performance and quantity of features. This single-board design

shows Mobilink's capability to provide the total solution for low-power

GSM multi-band handset applications. By using the circuitry and

software employed by the MTI-1400 design, customers can quickly

and easily create a unique product to their own specifications.

Designed to ensure low-cost production goals, Mobilink employs a

six-layer and five-mil PCB design rule process. The drill hole diameter

is no smaller than 10mil to avoid the extra cost of optical drilling.

Blind-via technology is applied instead of expensive micro-via design.

The result is approximately 1200mm2 of baseband circuit area and

2800mm2 of RF circuit area.

All baseband and RF circuitry fits onto a single board. Since it is a

single board design, manufacturing costs are reduced relative to

conventional multi-board designs. Connectors exist for the LCD

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panel, SIM card, battery charger, antenna and system accessories

and one side of the board has keypad patterns.

Software components for the LCD and keypad are easily altered for

specific changes and the memory system can be changed from the

128K x 8 SRAM and 512K x 16 FLASH provided. The flexible

architecture of the baseband codec hardware allows customers to

choose from a wide variety of microphones and speakers.

The Mobilink MTI-1400 Reference Design above is a dual-band GSM

handset on a single PCB. This solution demonstrates how a Mobilink

ML2000-family chip can be used to create dramatically smaller dual-

band handsets, at lower costs than current multi-board solutions. The

single-board design greatly simplifies the manufacturing processes

and enhances product reliability.

Voice quality can be either Full Rate or Enhanced Full Rate. Higher

rate wireless e-mail and data transfers are possible via Phase 2+

14.4 Kbps data service.

The long talk and standby times of the MTI-1400 Handset Reference

Design results from the use of a low, 2.8V supply voltage and

intelligent power management, including power-down scheduling for

on-chip functions and external components during inactive intervals.

The very long standby time is achieved via smart microprocessor

scheduling and power-efficient sleep-mode design.

To accelerate our customer's product development cycle, we also

offer total system solutions including the evaluation board, complete

system software, and extensive hardware and software support

through Full Type Approval (FTA).

Starting with this compact design, Mobilink's engineering teams work

with customers in BOM optimization, and feature and form factor

customization, in order to match every detail of the requirements.

Mobilink's in-house expertise allows customers to add or alter

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software and mechanical features or hardware interfaces, and quickly

get a product design through Type Approval and field trials. This

industry-leading design demonstrates Mobilink's commitment to low-

cost, low-power, high-performance RF design.

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EXPERIMENT NO. 8

AIM: To GSM architecture in cellular system

Introduction

GSM, the Global System for Mobile communications, is a digital cellular communications system which has rapidly gained acceptance and market share worldwide, although it was initially developed in a European context. In addition to digital transmission, GSM incorporates many advanced services and features, including ISDN compatibility and worldwide roaming in other GSM networks. The advanced services and architecture of GSM have made it a model for future third-generation cellular systems, such as UMTS. This paper will give an overview of the services offered by GSM, the system architecture, the radio transmission structure, and the signaling functional architecture.

History

GSM, the most successful digital cellular network, is the European digital cellular standard published by ETSI (the European Telecommunications Standards Institute). There are three phases for GSM technology creation.

1. Introduction of commercial GSM services, including telephony, short message, fax and data services in 1992.

2. In 1996, phase 2 completed the original GSM design task and established a framework for ongoing technology enhancement.

3. GSM standardization is now in phase 2+, in this phase. It includes improved voice coding and advanced data transmission services. Two data services are high-speed circuit-switched data service (HSCSD) and the General Packet Radio Service (GPRS).

System Architecture

The functional architecture of a GSM system can be broadly divided into the mobile station, the base station subsystem, and the network subsystem. Each subsystem is comprised of functional entities which communicate through the various interfaces using specified protocols.

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The GSM system architecture includes following subsystems (Figure 1): Mobile Station (MS), Base Station Subsystem (BSS), Network and Switching Subsystem (NSS).

1. Mobile Station:

The MS subsystem involves a radio part, an interface, and a Subscriber Identity Module (SIM). The radio part carries out all the functions related to the radio interface (Um), e.g. receiving and transmitting radio signals, signal processing, frequency hopping, and channel management. The interface to terminal equipment acts as a gateway between the terminal and the radio part. The SIM contains all the subscriber-related information on the MS side of Um to identify a subscriber and take care of the security. The SIM is implemented as a smart card.

The BSS forms cell structure of GSM network. It includes two types of network elements: the Base Transceiver Station (BTS), and the Base Station Controller (BSC).

The BTS is a transmission component. It carries out radio signal transmission and reception; signal processing, speech encoding and decoding, and transmission rate adaptation. The BSC is a managing component. It is responsible for all the management of the Um, e.g. channel allocation and de-allocation, handover, and timing of radio signals. One BTS implements one cell in GSM. A BSC can manage several BTSs.

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2. Base Station Subsystem:

The Base Station Subsystem is composed of two parts, the Base Transceiver Station (BTS) and the Base Station Controller (BCS). The BTS houses the radio transceivers that define a cell and handles the radio (Um) interface protocols with the mobile station. Due to the potentially large number of BTSs, the requirements for a BTS are ruggedness, reliability, portability, and minimum cost. The Base Station Controller (BSC) manages the radio resources for one or more BTSs, across the Abis interface. It manages the radio interface channels (setup, teardown, frequency hopping, etc.) as well as handovers.

3. Network and Switching Subsystem:

The central component of the Network Subsystem is the Mobile services Switching Center (MSC). It acts like a normal switching node of the PSTN or ISDN, and in addition provides all the functionality needed to handle a mobile subscriber, including registration, authentication, location updating, inter-MSC handovers, and call routing to a roaming subscriber. These services are provided in conjunction with four intelligent databases, which together with the MSC form the Network Subsystem. The MSC also provides the connection to the public fixed networks. The Home Location Register (HLR) contains all the administrative information of each subscriber registered in the corresponding GSM network, along with the current location of the subscriber. The location assists in routing incoming calls to the mobile, and is typically the SS7 address of the visited MSC. There is logically one HLR per GSM network, although it may be implemented as a distributed database. The Visitor Location Register contains selected administrative information from the HLR, necessary for call control and provision of the subscribed services, for each mobile currently located in the geographical area controlled by the VLR. Although the VLR can be implemented as an independent unit, to date all manufacturers of switching equipment implement the VLR together with the MSC, so that the geographical area controlled by the MSC corresponds to that controlled by the VLR. The proximity of the VLR information to the MSC speeds up access to information that the MSC requires during a call. The other two registers are used for authentication and security purposes. The Equipment Identity Register (EIR) is a database that contains a list to fall valid mobile equipment on The network, where each mobile equipment is identified by its International Mobile Equipment Identity (IMEI). An IMEI is marked as invalid if it has been reported stolen or is not type approved. The Authentication Center (AuC) is a protected database that stores a copy of the secret key stored in each subscriber’s SIM card, used for authentication and ciphering on the radio channel.

GSM services

GSM has three types of services: teleservices, bearer services, and supplementary services. Teleservices include telephony, fax, emergency

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calls, teletex, short Message services, fax mail, and voice mail. Supplementary services include call forwarding, call barring, etc. Bearer services are used for transporting user data. Some of the bearer services are listed below:

1. Asynchronous and synchronous data, 300-9600 bps. 2. Alternate speech and data, 300-9600 bps. 3. Asynchronous PAD (packet-switched, packet assembler/dis-

assembler) access, 300-9600 bps. 4. Synchronous dedicated packet data access, 2400-9600 bps.

Conventional GSM has limitations in data services:

1. It does not provide direct connection to the Internet. In order to access to the Internet, GSM needs to call Internet Service Provider (ISP).

2. Uplink and downlink channels allocated for a user are for entire call period.

3. It has time-oriented charging, that is, payment is based on connection time, not on data volumes.

4. Connection setup takes about 20-25 seconds. 5. Limited capacity (9600 bps). 6. GSM was designed for speech, not for data, hence 50% radio

capacity is wasted, and also there is no optimal channel coding for data.

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