Mobile Communication Systems

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Simplified 3GPP WLAN Network Model

Basic Cellular System Architecture

Mobile Communication SystemsLow tier wireless systemsHigh tier cellular telephony

Low Tier Wireless SystemsLow tier cordless telephonyCT2 (Cordless Telephone, Second Generation)DECT (Digital European [Enhanced] Cordless Telephone)Low tier personal communications system (PCS)PHS (Personal Handy phone System)PACS (Personal Access Communications System)

DECTPHS

Comparison of Low Tier Wireless Systems

High Tier Cellular Telephony

(microcell)(capacity)cell

Global

Suburban

Macro-Cell

Urban

Micro-Cell

In- Building

Pico-Cell

Home-Cell

Femtocell Access to the Core Mobile Network via Broadband Internet

Hierarchical Cell Structure

High-Tier (2G) vs. Low-Tier

(2G) () (0.5~35 Km) (50~500 m) (50~100 m) (257 Km/hr) (96 Km/hr) (48 Km/hr)(Coverage)large / continuousmacro cellsmedium / micro and picocellssmall / zonal picocells (100~ 800mW) ( 5~10mW) (5~10mW) (8~13kb/s) (32kb/s) (32kb/s)( 600ms)( 20ms) (10ms)

Comparison of High-Tier Cellular Systems (1G & 2G)

First Generation Cellular Systems and Services

1970sDevelopments of radio and computer technologies for 800/900 MHz mobile communications1976WARC (World Administrative Radio Conference) allocates spectrum for cellular radio1979NTT (Nippon Telephone & Telegraph) introduces the first cellular system in Japan1981NMT (Nordic Mobile Telephone) 900 system introduced by Ericsson Radio System AB and deployed in Scandinavia1984AMPS (Advanced Mobile Phone Service) introduced by AT&T in North America

1G1980AMPS

(cordless telephony)(PSTN)(PBX)CT1 CT2CT3(DECT)

CTG1G2CT-2CT-2+CT-3

CT-0MPT1322 (CT-0)(analog) FM

CT-1CEPT (Conference Europeenne des Postes et Telecommunications)900MHz analog FM CT-1FDMA/FDD

CT-1+Telepoint ()Telepoint100mCT1(CT0)

AMPSAMPS (Advanced Mobile Phone Service)19641970(FDMA)

50MHZAMPS824-849MHz (25MHz)869-894MHz (25MHz)832416(downlinks)416(uplinks)

AMPS(cluster)AMPSEIA/TIA IS-41

AMPS

Second Generation Cellular Systems and Services

1982CEPT (Conference Europeenne des Post et Telecommunications) established GSM to define future Pan-European Cellular Radio Standards1990Interim Standard IS-54 (USDC) adopted by TIA (Telecommunications Industry Association)1990Interim Standard IS-19B (NAMPS) adopted by TIA1991Japanese PDC (Personal Digital Cellular) system standardized by the MPT (Ministry of Posts and Telecommunications)1992Phase I GSM system is operational1993Interim Standard IS-95 (cdmaOne) adopted by TIA1994Interim Standard IS-136 (D-AMPS) adopted by TIA1995PCS Licenses issued in North America1996Phase II GSM operational1997North American PCS deploys GSM, IS-54, IS-951999IS-54: North AmericaIS-95: North America, Hong Kong, Israel, Japan, China, etcGSM: 110 countries

2G199001

+()

ExampleGSMWAP(circuit-switch)(packet-switch)ExamplePHSGSM50%~60%7006-810GSM1/601/100100

PHSGSM/ PHS GSM 500 20 100/ 120/ 80 100 10 600~1000 600 300 6-8 2~3 32k, 64k, 128k 9.6k

9.6Kbps (GSM)64Kbps (PHS)GSM64K9.6KPHS64K32K

CT-21989CT-2()Telepoint(handoff)864-868 MHz100 KHz40FDMA32kbps

(Time Division DuplexingTDD)(uplink)(downlink)(time-interleaved)(speech codec)2.4kbps~4.8kbpscodec (coder/decoder)10mW

CT-2+(roaming)(Common Air InterfaceCAI)CT2/CAI()handoff

CT-3CT-2/CT-2+CT-3WPBX (Wireless PBX)DECT

DECT1992(pico cell)1880-1900MHzTDMA12CT2TDD32kbpsCell sizeMicro-cell100~500Pico-cell100

(Dynamic Channel Allocation, DCA)timeslot(time slot transfer)()(Private Branch ExchangePBX)(PSTN)(seamless handoff)GSMDECTGSM(dual mode)DECTGSM

(connectionless datagram service)(multicast)(broadcast)(virtual circuits)(authentication)(confidentiality)

PHS1993RCR (Research and development Center for Radio system)TDMA1895~1918.1MHz77300KHz37(1895MHz-1906MHz)/40(1906.1MHz-1918.l MHz)

DECTPHSDECTPHS(dedicated control channel)(signaling)32kbpsTDD

PHS4.2~7.8kbps(full-duplex modem)2.4~9.6kbpsGSM32~64k128KPHS(www.phs.com.tw)

PACSPHS(Wireless Access Communications System)Belllcore1930-1990 MHz (base station transmission)1850-1910 MHz (handset transmission)PACSTDMA8

CT2PHSDECTPACS32kbpsCT2PHS DECTPACSTDDFDDFDD(uplink)(downlink)IS-41PACS (circuit switching)(packet switching)

DAMPSDAMPSDigital AMPSEIA/TIA IS-136 Digital Cellular System1987EIA/TIA IS-54IS-54IS-136TDMADAMPSADC (American Digital Cellular)NA-TDMA (North American TDMA)

TDMAIS-136AMPS869-894 MHz (base station transmission)824-849 MHz (handset transmission)

full-ratetimeslot13kbps8kbpshalf-ratetimeslot5kbps4kbps

IS-136AMPSIS-136(point-to-point short messaging)(broadcast messaging)(group addressing)(private user group)(hierarchical cell structure)

Hierarchical Cell Structure

DAMPS(slotted paging channel) (sleep mode)DAMPSIS-41

EIA/TIA IS-951940CDMA1970-1980.1993QualcommCDMAIS-95.Qualcomm1996cdmaOne (i.e., IS-95)1991IS-951997

IS-95CDMADSSSCDMACDMATDMA3-6CDMA8kbps13kbps8kbpsIS-95AMPS (FDMA)9

IS-95soft handoffRAKE receivermultipath fadingIS-95 (multipath)IS-95air-interfacecdmaOne IS-95A cdmaOne IS-95B cdma 2000 cdma2000 1XEV (CDMA MC FDD)

IS-95core networkcdmaOneIS-41 cdma2000 IS-41+Simple IP cdma2000 1xEV(cdma MC FDD) IS-41+Mobile IP

GSMGSM (Global System for Mobile Communications)(Conference Europeenne des Postes et Telecommunications, CEPT)(European Telecommunications Standard Institute, ETSI)1983

uplink (handset transmission)890-915 MHz (25MHz)downlink (base station transmission)935-960 MHz (25MHz)FDMA/TDMA/FDD

(FDMA)(TDMA) (frequency carrier)(time slot) 0.577ms (=0.546ms+0.031ms)4.615ms(time frame)

GSM

GSM8(speech coding)l3KbpsGSM8GSMGSM MAP (Mobile Application Part)(IS-41)

GSM System Architecture

NSS(Network and Switch Subsystem)MSC(Mobile Switching Center)BSS(Base Station Subsystem)BSC(Base Station Controller)BTS(Base Transceiver Station)MS(Mobile Station)ME(Mobile Equipment)SIM(Subscriber Identity Module)

2.5GGSM+(High Speed Circuit Switched DataHSCSD)(General Packet Radio ServiceGPRS)GSM++(Enhanced Data rates for Global EvolutionEDGE)

GPRS System Architecture

GPRSGeneral Packet Radio Service171.2Kbps (21.4Kbps8 )GSM(Channel Coding UnitCCU)(Packet Control UnitPCU)

(CCU)(error protection)CS-1 (9.05K)CS-2 (13.4K)CS-3 (15.6K)CS-4 (21.4K)

(PCU)GSM

IPGPRS(SMS over GPRS) QoS

EDGEEDGE (Enhanced Data rates for GSM Evolution)2G2.5G (GPRS)2.75G3GGSMGPRS(GMSK8PSK)EDGEEDGEGPRSGSM

384kbpsISPEDGE(Radio Access)(BTS)(BSC)MSC (Mobile Switching Center)SGSN (GPRS Support Node)

3G+2Mbpsseamless2G

(GSMCDMATDMA)()()W-CDMA/UMTS ()CDMA2000 ()TD-SCDMA ()

W-CDMAW-CDMA(Wideband CDMA)CDMA Direct SpreadGSMUMTS (Universal Mobile Telecommunication System)(modes of operation)20 +15 MHz for unpaired UTRATDD mode used by TD-CDMA1900 ~ 1920 + 2010 ~ 2025 35Mz

60+60 MHz for paired UTRAFDD mode used by WCDMAuplink1920~1980 60Mzdownlink2110~2170 60MzSatellite UMTS (S-UMTS)GSM 1800DECT

CDMA2000CDMA2000CDMA Multi-CarrierCDMACDG (CDMA Development Group)cdmaOne (IS-95)

CDMA2000CDMA2000 1x (307 kbps)CDMA2000 3xMC (384 kbps)(Multi CarrierMC)31.25 MHz3.75 MHzCDMA2000 1xEV-DO (2.4Mbpsdata only) DO (Data Optimization)(8PSK, 16QAM)2.4 MbpsCDMA2000 1xEV-DV (Evolution-Data/Voice) (4.8Mbps)

TD-SCDMATD-SCDMA (Time Division Synchronous CDMA)CWTS (China Wireless Telecommunication Standards)CATT (China Academy of Telecommunication Technology)(Siemens)

TD-SCDMA2010~2025MHz ()1.6MHz ()(chip rate)1.28Mbps10ms7QPSK8PSK200Hz 2.048 Mbps ()

2G2.5G3G

Air InterfaceCDMA IS-95A (voice14.4 kbps) IS-95B (voice, 64 kbp) cdma2000 1x (307 kbps) cdma2000 3xMC (384 kbps) 1xEV-DO (2.4Mbpsdata only) 1xEV-DV ()IS-136 (voice9.6 kbp) ? (cdma2000 1x1xEV-DO)

GSM (voice9.6 kbps) GSM GPRS (80 kbps) EDGE (240 kbps) UMTS UMTS/HSDPA ()PDC (voice9.6 kbps) P-PDC (voice28.8 kbps) WCDMA ()NTT DoCoMoMarch1999packetPDCP-PDCiModeP-PDCARIBETSI3GPPWCDMANTT DoCoMo2001WCDMA

3GPP (The 3rd Generation Partnership Project) A collaboration between groups of telecommunications associationsMake a globally applicable third generation (3G) mobile phone system specification within the scope of the International Mobile Telecommunications-2000 (IMT-2000) project of the International Telecommunication Union (ITU)3GPP specifications are based on evolved Global System for Mobile Communications (GSM) specifications3GPP standardization encompasses Radio, Core Network and Service architecture

IMT-2000 Fulfill one's dream of anywhere, anytime communications a realityThe global standard for third generation (3G) wireless communications as defined by the International Telecommunication Union (ITU)Compatibility of services within IMT-2000 and with the fixed networkshigh qualitysmall terminal for worldwide useworldwide roaming capabilitycapability for multimedia applications, and a wide range of services and terminals

Important component of IMT-2000 is the ability to provide high bearer rate capabilities2 Mbps for fixed environment384 kbps for indoor/outdoor and pedestrian environments144 kbps for vehicular environmentRadio interface standards for IMT-20001999, ITU approved five radio interfaces for IMT-2000 as a part of the ITU-R M.1457 Recommendation2007, additionally approved a new standard as the sixth IMT-2000 radio interface

The six IMT-2000 radio interface standardsIMT-DS Direct-Sequenceknown as W-CDMA or UTRA-FDDused in UMTSNoteUTRA -- UMTS Terrestrial Radio AccessIMT-MC Multi-Carrierknown as CDMA2000the successor to 2G CDMA (IS-95)

IMT-TD Time-DivisionTD-CDMA (Time Division - Code Division Multiple Access)standardized in UMTS by the 3GPP as UTRA TDD-HCR (high chip rate)3.84 Mcps, 5 MHz bandwidthTD-SCDMA (Time Division - Synchronous Code Division Multiple Access)standardized in UMTS by the 3GPP as UTRA TDD-LCR (low chip rate)1.28 Mcps, 1.6 MHz bandwidth

IMT-SC Single Carrierknown as EDGE (Enhanced Data rates for GSM Evolution)EDGE Evolution, added in Release 7 of the 3GPP standard, provides reduced latency and potential speeds of 1Mbps by using even more complex coding functionsIMT-OFDMA TDD WMANbetter known as WiMAX

IMT-FT Frequency Timeknown as DECT (Digital Enhanced Cordless Telecommunications)DECT IMT-2000: up to 2.5 Mbps user data rate (1999)Beyond IMT-2000: up to 15 Mbps (single and wide carrier 64-QAM modulation)

DECT Life Cycle

OFDM based up to 20MHz

UMTS/WCDMA System Architecture

IP Multimedia Subsystem (IMS) An architectural framework for delivering Internet Protocol (IP) multimedia servicesOriginally designed by the wireless standards body 3rd Generation Partnership Project (3GPP), as a part of the vision for evolving mobile networks beyond GSMIts original formulation (3GPP R5) represented an approach to delivering "Internet services" over GPRSthis vision was later updated by 3GPP, 3GPP2 and TISPAN by requiring support of networks other than GPRS, such as Wireless LAN, CDMA2000 and fixed line

To ease the integration with the Internet, IMS uses IETF protocols wherever possible, e.g. Session Initiation Protocol (SIP)According to the 3GPP, IMS is not intended to standardize applications but rather to aid the access of multimedia and voice applications from wireless and wireline terminals, i.e. create a form of Fixed Mobile Convergence (FMC)This is done by having a horizontal control layer that isolates the access network from the service layerFrom a logical architecture perspective, services need not have their own control functions, as the control layer is a common horizontal layer

3GPP Conceptual Network Architecture (Release 5)

HSDPA (High-Speed Downlink Packet Access) (3.5G) An enhanced 3G mobile telephony communications protocol in the High-Speed Packet Access (HSPA) familyAlso coined 3.5G, 3G+ or turbo 3GAllows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacityCurrent HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2, 14.4 Mbps Further speed increases are available with HSPA+, which provides speeds of up to 42.2 Mbps downlink

HSDPA (High-Speed Data Packet Access)3GPPR5UMTSHS-DSCH (High Speed Downlink Shared Channel)(bursty data)Node BMACMAC-hs (High Speed Medium Access protocol)(Hybrid Automatic ReQuest HARQ)(Adaptive Modulation and CodingAMC)

10Mbps(384Kbps)(Adaptive Modulation and CodingAMC)(Hybrid Automatic ReQuestHARQ)(Multiple Input Multiple OutputMIMO)(Fast Cell SelectionFCS)

Adaptive Modulation and Coding (AMC) (or Link adaptation)a term used in wireless communications to denote the matching of the modulation, coding and other signal and protocol parameters to the conditions on the radio link

the signal and protocol parameters change as the radio link conditions change, e.g. the pathlossthe interference due to signals coming from other transmittersthe sensitivity of the receiverthe available transmitter power margin, etc.in HSDPA of UMTS this can take place every 2ms

Hybrid ARQ (HARQ)a variation of the ARQ error control methodStandard ARQ error-detection (ED) information bits are added to data to be transmitted (such as cyclic redundancy checkCRC)Hybrid ARQforward error correction (FEC) bits are also added to the existing error detection (ED) bits

Hybrid ARQ performs better than ordinary ARQ in poor signal conditions, but in its simplest form this comes at the expense of significantly lower throughput in good signal conditionsthere is typically a signal quality cross-over point below which simple Hybrid ARQ is better, and above which basic ARQ is better

MIMO (Multiple-Input and Multiple-Output) (antennas)refers to the use of multiple antennas both at the transmitter and receiver to improve the performance of radio communication systemsMIMO technology has attracted attention in wireless communications, since it offers significant increases in data throughput and link range without additional bandwidth or transmit powerit achieves this by higher spectral efficiency (more bits per second per Hertz of bandwidth) and link reliability or diversity (reduced fading)

FCS (Fast Cell Selection)FCSActive SetFCS

Peak User Data Rates (bps) - Theoretical42.2MHSDPA UE Cat.20

HSUPA (High Speed Uplink Packet Access) (3.75G) Use an uplink enhanced dedicated channel (E-DCH)Employ link adaptation methods shorter Transmission Time Interval (TTI) enabling faster link adaptationHARQ (hybrid ARQ) with incremental redundancy making retransmissions more effective

PTT (Push-To-Talk)Also known as Press-To-TransmitA method of conversing on half-duplex communication lines, including two-way radioUsing a momentary button to switch from voice reception mode to transmit mode

GAN (Generic Access Network)UMA (Unlicensed Mobile Access)the commercial name of the 3GPP GAN, or GAN standardThe most common application of GAN is in a dual-mode handset service where subscribers can seamlessly roam and handover between local area networks and wide area networks using a GSM/Wi-Fi dual-mode mobile phoneGAN enables the convergence of mobile, fixed and Internet telephony, sometimes called Fixed Mobile Convergence (FMC)

HSOPA (High Speed OFDM Packet Access) (3.9G)A proposed part of 3GPP's Long Term Evolution (LTE) upgrade path for UMTS systemsHSOPA is also often referred to as Super 3GIf adopted, HSOPA succeeds HSDPA and HSUPA technologies specified in 3GPP releases 5 and 6Unlike HSDPA or HSUPA, HSOPA is an entirely new air interface system, unrelated to and incompatible with W-CDMA

HSOPA featuresflexible bandwidth usage with 1.25 MHz to 20 MHz bandwidthsby comparison, W-CDMA uses fixed size 5 MHz chunks of spectrumincreased spectral efficiency at 2-4 times more than that in 3GPP release 6, peak transfer rates of 100 Mbps for downlink and 50 Mbps for uplink

latency times of around 20 ms for round trip time from user terminal to RAN, approximately the same as a combined HSDPA/HSUPA system, but much better than "classic" W-CDMAuses Orthogonal Frequency Division Multiplexing (OFDM) and multiple-input multiple-output (MIMO) antenna technology to support up to 10 times as many users as W-CDMA based systems, with lower processing power required on each handset

NFC (Near Field Communication)A short-range high frequency wireless communication technology which enables the exchange of data between devices over about a 10 centimeter (around 4 inches) distanceThe technology is a simple extension of the ISO 14443 proximity-card standard (contactless card, RFID) that combines the interface of a smartcard and a reader into a single device

an NFC device can communicate with both existing ISO 14443 smartcards and readers, as well as with other NFC devices, and is thereby compatible with existing contactless infrastructure already in use for public transportation and paymentNFC is primarily aimed at usage in mobile phones

LTE (Long Term Evolution)LTE meets key requirements of next generation networksdownlink peak rates: at least 100Mbit/suplink peak rates: 50 Mbit/sRAN (Radio Access Network) round-trip times: less than 10ms

Goalsimprove spectral efficiencylower costsimprove servicesmake use of new spectrumbetter integration with other open standards

Main advantageshigh throughputlow latencyplug and play FDD and TDD in the same platformsuperior end-user experiencesimple architecture resulting in low Operating Expenditures (OPEX)seamless connection to existing networks, such as GSM, CDMA and HSPA

3GPP LTE Spectrum

Taiwan: Mobile Communication Spectrum Allocation

LTE

MIMOMultiple Input Multiple Output

CoMPCoordinated Multiple Point

LTE Requirements and Performance Targets)

LTE / SAE Long Term Evolution / System Architecture EvolutionLTE / SAEE-UTRAN (Evolved UTRAN) on the access sideE-UTRAN is also known as LTEEPC (Evolved Packet Core) on the core sideEPC is also known as SAE (System Architecture Evolution)

Network Architecture of LTE

SAE (EPC) Architecture

SAE (EPC) Architecture Functions per ElementMME (Mobility Management Entity)manages and stores the UE control plane context, generates temporary id, UE authentication, authorization of TA/PLMN, mobility managementUPE (User Plane Entity)manages and stores UE context, DL UP termination in LTE_IDLE, ciphering, mobility anchor, packet routing and forwarding, initiation of paging3GPP anchor (Serving Gateway, S-GW)mobility anchor between 2G/3G and LTESAE anchor (PDN Gateway, P-GW)mobility anchor between 3GPP and non 3GPP (I-WLAN, etc)

Evolved Packet Core All-IP core for LTEServing Gateway (SG-W)Packet Data Network (PDN) Gateway (PGW)Mobility Management Entity (MME)Policy and Charging Rules Function (PCRF) [A new converged architecture to allow the optimization of interactions between the Policy and Rules functions.]

Simplified architecturecost efficient 2 node architecturefully meshed approach with tunneling mechanism over IP transport networkmost of the RNC functionalities moved to the eNode BUTRAN RNC removedeNodeB connected directly to the evolved packet core

Network Simplification: from 3GPP to 3GPP LTE

LTE: Evolution from Separate CS and PS Core Sub-domains to One Common IP Core

Control-plane :UE eNB MME User-plane:UE eNB S-GW P-GW

EPC Architecture Functional Description of the Nodes

*LTE vs. WiMAX

3GPP2 (The 3rd Generation Partnership Project 2)The 3rd Generation Partnership Project 2 (3GPP2) is a collaboration between telecommunications associations to make a globally applicable third generation (3G) mobile phone system specification within the scope of the ITU's IMT-2000 project3GPP2 is the standardization group for CDMA2000, the set of 3G standards based on earlier 2G CDMA technology

4GA fully IP-based integrated system of systems and network of networksConvergence of wired and wireless networks as well as computer, consumer electronics, communication technologyBe capable of providing 100 Mbps and 1 Gbps, respectively, in outdoor and indoor environmentsEnd-to-end quality of service and high securityOffering any kind of services anytime, anywhere, at affordable cost and one billing

Some Milestones in Wireless Communications

4G is being developed to accommodate the quality of service (QoS) and rate requirements set by forthcoming applications like wireless broadband accessMultimedia Messaging Service (MMS)video chatmobile TVHDTV contentDigital Video Broadcasting (DVB)minimal service like voice and dataother streaming services for anytime-anywhere

Objectivesa spectrally efficient system (in bits/s/Hz and bits/s/Hz/site)high network capacity: more simultaneous users per cella nominal data rate of 100 Mbps while the client physically moves at high speeds relative to the station, and 1 Gbps while client and station are in relatively fixed positions as defined by the ITU-Ra data rate of at least 100 Mbps between any two points in the worldsmooth handoff across heterogeneous networks

seamless connectivity and global roaming across multiple networkshigh quality of service for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc)interoperability with existing wireless standardsan all IP, packet switched network

Design Objectives

4G conceptsupports user driven, user controlled services and context-aware applicationsUser controlled servicesuser has freedom and flexibility to select any desired service with reasonable QoS and affordable price, anytime, anywhere

Context-aware applicationsthe behavior of the application adapts itself to user context changesuser context includesuser profile and preferencesuser terminal and network capabilitiesuser environment and mobility

Network level conceptsinterworking / integration / convergence (cell & WLAN, cell & broadcast) of all existing and emerging fixed and mobile (wired and wireless) networks including broadcast

Interworking for 4G

BBU (Base Band Unit)RRU (Radio Remote Unit)BBURRU

Mobile Going Broadband into the Cloud

Hierarchical Layers for 4G

Integration

Mobile Internet Access Methods

********TelegraphScandinavia

*********Aka TIA/EIA-41 or ANSI-41Allows for the implementation of mobile network signaling infrastructureTargeted to the CDMA, TDMA, and AMPS networksThe basis for providing mobility characteristicsPremiseConnect the distributed switching elements, called mobile switching centers (MSCs) with a master database called the Home Location Register (HLR) and other centralized network databasesThe HLR dynamically stores the current location and profile of a mobile network subscriberThe HLR is consulted during the processing of an incoming callVia IS-41 the HLR is updated as the subscriber moves about the network and is serviced by different switches within the network***************************CEPTETSI**********************High-tier & Low-tier System1st groupJTACS (Japanese Total Access Communication System1988)JDC (Japanese Digital Cellular)2nd groupTACS (Total Access Communication System) NMT (Nordic Mobile Telephone)GSM (Global System of Mobile Communication)3rd groupAMPS (Advance Mobile Phone System)NDAC (North American Digital CellularIS-54D-AMPS) PCS (Personal Communication Services)4th groupCT0/1/2 (Coreless Telephone)DECT (Digital European Cordless TelecommunicationsCT-3)PHS (Personal Handyphone System)PACS (Personal Access Communication System)

***EDGEcoding schemeair interfacecapacityefficiencycore networkcost-efficient migration**Bearer servicea telecommunications term referring to a service that allows transmission of information signals between network interfaces. These services give the subscriber the capacity required to transmit appropriate signals between certain access points, i.e. user network interfaces.The bearer services include the followinga) Rate adapted sub-rate information like circuit switched asynchronous and synchronous duplex data, 300-9600 bits.b) Speech and data swapping during a call, i.e. alternate speech and data.c) Modem selection, i.e. selection of 3.1 kHz audio service when inter-working with ISDN.Carrier wavea waveform suitable for modulation by an information-bearing signal.Multi-Carrier Code Division Multiple Access (MC-CDMA)a multiple access scheme used in OFDM-based telecommunication systems, allowing the system to support multiple users at the same time.McpsIn direct sequence spread spectrum technologies such as DSSS and CDMA, it is the number of bits per second (chips per second) used in the spreading signal. A different spreading signal is added to the data signal to code each transmission uniquely. Chip rate is measured in "megachips per second" (Mcps), which is millions of chips per second.******Momentary;*Proximity,********ITU-R: ITU Radiocommunication SectorITU-T: ITU Telecommunication Standardization SectorSpectral efficiency, spectrum efficiency or bandwidth efficiency refers to the amount of information that can be transmitted over a given bandwidth in a specific communication system. It is a measure of how efficiently a limited frequency spectrum is utilized by the physical layer protocol, and sometimes by the media access control (the channel access protocol).*****