GSM Fundamental Principle

Radio Network Planning & Optimization DeptMobile Division

After studying this course, you will be able toUnderstand the system structure and GSM service functions.Familiar with GSM s theory of radio interface and key technology.Master the fundamental signal flow of GSM.Know numbering plan of GSM.Course Target

Summary of GSM Mobile CommunicationStructure of GSM System Theory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile Communication Catalogue

Summary of GSM Mobile CommunicationSimple History of GSM Development users requirementcompetition enhancingtechnology development

Summary of GSM Mobile CommunicationRequirement of GSM SystemGSM System Criterion & Business RequirementEach country should have more than two equipment merchantsin order to living and compete together.GSM must be an open system, and be convenience for equipment merchants to live and compete.The import of GSM has no effect on PSTN.Requirement of GSM System Criterion Technology The system must be used widely in Europe.The system must keep good quality of telecommunication voice.The system must try it best to use radio frequency effectively.The system must have enough capacity.The system must be compatible with other criterion of other digital communication.The system must keep safety in users and sending messages.

Summary of GSM Mobile CommunicationAdvantage of GSM SystemThe advantages of GSM system standard are as followsThe system can allow more interval interference.can obtain better average voice quality than simulative cell system.The network sustains data transmissionVoice encryption and users information security are ensured.It is compatible with ISDNalso its simulative system can provide new services.in those countries who adopt GSM systemthe technology of international roam becomes possible.Enormous market aggravates competitionIt reduces investment and using price.

Summary of GSM Mobile CommunicationFunctions of GSM System ServiceFundamental Services that GSM providedCarrier ServiceTelecom ServiceFundamental Carrier ServiceSupplemental ServiceSupplemental ServiceSMS ServiceVoice ServiceData Servicemost important

Criterion of GSM01 SeriesSummary of System02 SeriesService03 SeriesNetwork Structure & Network Function04 SeriesRadio Interface SignalL2L305 SeriesPhysical Level of Radio Interface06 SeriesVoice EncodingFREFRHRSummary of GSM Mobile Communication

Criterion of GSM07 SeriesAdapting Functions of Mobile Terminal. 08 SeriesA Interface & Abis Interface09 SeriesNetwork InterlinkageISDNPSTNPSPDN10 SeriesPH2new Functions11 SeriesTesting12 SeriesNetwork Managementmanipulation maintenancethe monitoring of users and terminals service data performance and equipment management

Summary of GSM Mobile Communication

Summary of GSM Mobile CommunicationStructure of GSM SystemTheory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile CommunicationCatalogue

Structure of GSM System

Each module function of GSM systemStructure of GSM SystemMS (Mobile Station)MS is used to realize mobile terminal functions.BTS (Base Transceiver Station)BTS is used to realize radio communication between mobile communication system and MS.BSC (Base Station Controller)BSC is used to realize hub function from radio system to switch system, the function of radio resource management and other control functions related to radio .

Function of GSM systems each moduleStructure of GSM SystemHLR (Home Location Register)In fact it is a database used to store following datausers datamainly includinginformation of users positionVLR (Visitor Location Register)In fact it is a database which is used to store users information, mainly includesMSRN (Mobile Station Roaming Number) TMSI (Temporary Mobile Subscriber Identification)The Location Area Code of Mobile StationData Related to supplementary serviceUsers identification IMSI (International Mobile Subscriber Identification)Users ISDN numberVLR address

Function of GSM systems each moduleStructure of GSM SystemMSC (Mobile Service Switching center)It is used to realize switch function of mobile service.AUC (Authentication Center) : It is used to authenticate users identity.EIR (mobile station Equipment Identity Register) : It is used to store and authenticate the identity of mobile stations equipmentsOMC (Operation & Maintenance Center)It is used to monitor and control system equipments.

GSM three network subsystemsStructure of GSM SystemGSM network is consist of three network subsystems.Abis

BSS SystemStructure of GSM SystemBSS is consist of the following unitsBSC (Base Station Controller)BTS (Base Station)TC TranscoderBSS main functionsRadio control network & managementconvert voice to codeAir interface signal & data processingTo link NSS signal and air

NSS SystemStructure of GSM SystemNSS is consist of following unitsMSC Mobile service Switching CenterHLR Home Location Register VLR Visitor Location Register AC Authentication CenterEIR Equipment Identity RegisterNSS Main FunctionsCalling controlCalculate the costMobile ManagementSignal related to other network base stationsUsers data processing Locate users position

NMS SystemStructure of GSM SystemNMS Main FunctionsEach function and unit of monitoring network. Malfunction ManagementConfiguration ManagementPerformance Management

Summary of GSM Mobile CommunicationStructure of GSM SystemTheory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile CommunicationCatalogue

Work Frequency BandTheory of GSM Radio Interface

GSM Systemup/ MHzdown/ MHzbandwidth/ MHzDuplex interval/ MHzNumber of Duplex channelsGSM900890 ~ 915935 ~ 9602 2545124GSM900E880 ~ 890925 ~ 9352 3545174GSM18001710 ~ 17851805 ~ 18802 7595374GSM19001850~19101930~19902 6080299

Work Frequency BandTheory of GSM Radio InterfaceChannel IntervalEach carrier frequency stands 200 KHz bandwidthit adopts TDMA and includes eight physical channels.Channel ConfigurationGSM900MHz frequency bandfu(n)=890.2MHz+(n-1)*0.2MHzfd(n)= fu(n)+45MHzGSM1800MHz frequency bandfu(n)=1710.2MHz+(n-512)*0.2MHzfd(n)= fu(n)+95MHzfu(n)uplink frequencyMS sendingBTS receivingfd(n)downlink frequencyBTS sendingMS receiving

Interference Protection RatioTheory of GSM Radio InterfaceCarrier Wave Interference Ratio --- C/IDefinitionThe ratio of anticipant level received and not-expected level received.Same Frequency Interference Protection Ratio ---C/IC/I means how much interference some cell affecting service cell when different cells use the same frequency.requirement of criterionC/I>=9dBrequirement of projectadd 3dB surplusi.e. C/I>=12dBAdjacent Frequency Interference Protection Ratio ---C/AC/A means how much interference some cell affecting service cell when different cells use adjacent frequency in different cells.Requirement of CriterionC/I>=9dBRequirement of Engineering add 3dB surplusi.e. C/I>=6dBThe interference protection ratio C/I is not less than -41dB when carrier frequency has a discrepancy of 400KHz.

Technology of Frequency Multi-usefrequency multi-useUsers in different location use the same frequency channel. It improves frequency efficiency greatly.The unreasonable system design may induce same frequency and adjacent frequency interference in the network easily.Theory of GSM Radio Interface(D/R)2 = 3*KD--the distance of frequency multi-use R--the radius of a cellK--the mode of frequency multi-use

Technology of Frequency Multi-useTheory of GSM Radio Interface

Technology of Frequency Multi-useGSM most basal frequency multi-use mode434 base stations3cells12 cells12 frequencies constitute a groupTheory of GSM Radio Interface

The technology of multiply accessNumerous subscribers use public telecommunication lines but dont disturb each other.Technology of Multiple AccessTheory of GSM Radio Interface

Multiple Access Technology - FDMAFDMATo realize different frequency channels.Theory of GSM Radio Interface

TDMATo realize communication by different timeslots.Multiple Access Technology - TDMATheory of GSM Radio Interface

CDMAUsing different code sequences to realize communication.Multiple Access Technology - CDMATheory of GSM Radio Interface

TDMA ChannelTheory of GSM Radio InterfaceTDMA ChannelPhysical ChannelLogic ChannelTraffic ChannelControl ChannelA physical channel is just a timeslot. Its definition is that give TDMA frame fixed positions timeslot .

Different logic channels are defined by message type that channels sent .It is delivered by BTS mapping it into different timeslots.

Physical Channel TSTheory of GSM Radio Interface

Traffic ChannelTheory of GSM Radio InterfaceTraffic ChannelIt is used to carry users data. It divides into voice traffic channel and digital traffic channel.Voice Traffic ChannelTCH/FSfull speed voice channel 13Kbit/sTCH/HShalf speed voice channel 5.6Kbit/sDigital Traffic ChannelTCH/F9.6full speed digital channel 9.6Kbit/sTCH/F4.8full speed voice channel 4.8Kbit/sTCH/H4.8half speed digital speed 9.6Kbit/sTCH/H2.4half speed voice channel

Control ChannelTheory of GSM Radio InterfaceControl Channelcarry signalsynchronize data

Broadcast Channel (BCH)Theory of GSM Radio Interface

CCCHTheory of GSM Radio Interface

DCCHTheory of GSM Radio Interface

TDMA FrameTheory of GSM Radio InterfaceEach carrier frequency is defined a frame. Each frame includes eight timeslots and its frame numberThe length of each timeslot is 0.577msKnow GSM Number Plan Briefly

Target1st restrain high frequency ponderance2nd avoid superfluous instantaneous frequency excursion3rd satisfy the requirement of coherent detection.Requirementout-of-band radiated power is6080dBFeaturesIts realization is simplealso it adds forward-filter at the basis of original MSK modulator. Gauss filterIts bandwidth is narrow and its type is sharp- cut. Lower extra impulse response. The area of output pulse is invariable.ApplicationGSM system.Gauss molding filterGMSK Modulation TechnologyTheory of GSM Radio Interface

Channel Encodinginterlacedcoderchannelinterlacedcoderinnerencoderinner decoderouter encoderouter decodervoice encodervoice encoder13 kbit/s33.9 kbit/s22.8 kbit/svoice outputvoice inputTheory of GSM Radio Interface

Complect Technology complect technology: let information code permutation and combination at sending side. Then the information is sent to channel later. In order to resume original code sequence the receiver will complete it. The terminal target is to covert impulse error into random error, then rectify it by channel encoding.Theory of GSM Radio Interface

Diversity TechnologyIt collects all switch signals by certain method .These multipath signals received are first divided into irrelevant multipath signals, from less to more. Then merge these signal energy again, so the energy become less. As a result, diversity technology improves receiving quality.Diversity technology includes time diversity, space diversity, frequency diversity, polarization diversity. Theory of GSM Radio Interface

DTXVADVoice Activation DetectVoice ControlIt adopts discontinuous transmission. In voice communication, each sides speaking time is less than 40 percent of conversational time when two sides talk to each other.The functions of DTXReduce interference, improve telecommunication quality and enhance capacity.Decrease transmitters power and prolong batterys working hours.Theory of GSM Radio Interface

Power Control TechnologyPower control: Its aim is to send minimum effective power on the premise that ensuring service quality, other than all base stations send maximum power that cell border required. To reduce same frequency interference.Dynamic power control: In conversation, the output power of base stations and the output power of mobile stations can be adjusted accompanying propagation path loss and signal quality change. As a result. propagation signal intensity in air is as little as possible, further the received signal that BTS and MS received also satisfies system anticipant value.

Theory of GSM Radio Interface

Time Ahead (TA)Theory of GSM Radio Interface

Technology of HopTheory of GSM Radio Interface

Summary of GSM Mobile CommunicationStructure of GSM SystemTheory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile CommunicationCatalogue

Functions of GSM Mobile Network Summaryfunctions of GSM system network Support communication service network function.Support systematic fundamental service & supplementary serviceensure establish telecom among system users.Mobile management network functions. Support all problems caused by users moving, including location update, handover, roaming.Safety management network functions.Support mobile subscriber authentication, mobile subscribers identification secrecy, usersdata secrecy, signal data secrecy and other safeguards.Support additional network functions of page processing.Support page rebuilding, queue, discontinuous receive and other additional network functions.Key point

Location UpdateFunctions of GSM Mobile NetworkLocation update is caused by mobile phone.Current location information is stored in your SIM card.Mobile phone monitors network information ceaselessly. Once finding current location info. isnt with the location stored in SIM card, It will update location

Location UpdateFunctions of GSM Mobile NetworkCategories of Location UpdateTurn on / off mobile phoneIMSI ATTACH/DETACHLocation RegisterMS is turned on or turned offNormal Location UpdateMS changes its locationPeriodical Location UpdateCarrier sets period When the interval between two location update exceeds such period, MS initiates location update.

Location UpdateFunctions of GSM Mobile NetworkSignal Flow

MS

BTS

BSC

MSC

CH REQ

CH RQD

CH ACT

CH ACT ACK

IMM ASS CMD

IMM ASS

SABM

UA

EST IND

CRLOC UPD REQ

CC

ENCRY CMD

CIPH MODE CMD

CIPH MODE COM

DICIPH MODE COM

DT1CIPH MODE CMD

DT1CIPH MODE COM

DTAPLOC UPD ACCEPT

DT1Clear CMD

DT1Clear COM

CH REL

DRCH REL

DEACT SACCH

DISC

UA

REL IND

RF CH REL

RF CH REL ACK

RLSD

RLC

MS original call-1Functions of GSM Mobile Network

MS original call -2Functions of GSM Mobile Network

MS terminal call-1Functions of GSM Mobile Network

MS terminal call-2Functions of GSM Mobile Network

HandoverWhy needs to handoverTo keep the consistency of call when MS is moving.To improve network service qualityReduce drop call rateReduce congestion rateWho takes part in handoverMSBTSBSCMSCMSTo measure the performance of radio subsystem downlink route and signal intensity received from surrounding cells .BTSmonitor the uplink receiving level and quality of each MS serviced, monitor interference level. The result will be sent to BSC.BSCThe first judgment is accomplished by BSC.MSCAs to other messages sent from BSS and MSCthe judgment of measuring result is accomplished by MSC.Functions of GSM Mobile Network

Handoverclassificationsorted by springing conditionsPower budget handoverSuccoring electronic level handoverSuccoring quality handoverDistance handoverVoice service handoversorted by fixed time aheadSynchronized handoverAsynchronized handover

sorted by calling locationHandover in a cellHandover among cellsHandover in a BSCHandover among BSCsHandover among MSCsFunctions of GSM Mobile Network

Handoverin a cellFunctions of GSM Mobile Network

Handoverin a cellFunctions of GSM Mobile Network

Handoveramong cellsFunctions of GSM Mobile Network

Handoverin a BSCFunctions of GSM Mobile Network

Handoveramong cells in the same BSCFunctions of GSM Mobile Network

Handoveramong cells in different BSCsFunctions of GSM Mobile Network

Handoveramong cells in different BSCsFunctions of GSM Mobile Network

Handoveramong cells is different MSCsFunctions of GSM Mobile Network

Handoverhandover signal flow among MSCsFunctions of GSM Mobile Network

Summary of GSM Mobile CommunicationStructure of GSM SystemTheory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile CommunicationCatalogue

Numbering Plan of GSMArea of GSM position PLMN areaMSC areaLAC areaBTS areaCELL areaGSM service area

Numbering Plan of GSMNumbering PlanMSISDNMSISDN (Mobile Subscriber Number)Original caller pages number that GSM mobile subscriber called.CCCountry CodeChinas CC is 86.NDCNational Destination CodeChina Mobile is from 135 to 139SNSubscriber number is a 8-digit codewhich is distributed by carrier himself.

Numbering Plan of GSMNumbering PlanIMSIIMSI (International Mobile Subscriber Identity)Every subscriber is distributed an unique IMSI. IMSI is effective in the whole GSM system, It is used to identify subscribers identity.MCCMobile Country Code. identify subscribers own countryChina is 460.MNCMobile Network Code. It is used to identify mobile subscriber own mobile communication network ---PLMNe.g. China Mobile is 01MSINMobile Station Identification Number. It is used to identify subscribers in Mobile Communication Network.NMSINational Mobile Station Identification Number.

Numbering Plan of GSMNumbering PlanTMSITMSI (Temporary Mobile Subscriber Identity )To transfer TMSI instead of IMSI in Um interface. As a result it enhances users safety.Mobile subscribers from VLR are distributed after successful authenticationVLR distributes a 4B BCD code by itself. However it is confined to temporarily use instead of IMSI in those areas dominated by VLR.Be correspond to IMSI.

Numbering Plan of GSMNumbering Plan MSRNMSRN (Mobile Station Roaming Number)MSRN is a temporary number for MS distributed by VLR when paging connection.Choose route when connecting in GSM network. The makeup of MSRN is similar to MSISDN, and MSRN is a number that less than 15-digit .

Numbering Plan of GSMNumbering PlanLAILAIDefinitionLAI is an area that MS can move anyway but doesnt need to update position. It is made of many cells.In order to page MSall cells in such area will send page signal at the same timeMSC area>=LA>= a cellFunction Detecting Request of update position and signal handover.LACIt is used to identify an area in GSM Networkand it is defined by carrier .

Numbering Plan of GSMNumbering PlanCGICGI (Cell Global Identity)CGI is an unique mark which is used to identify cell in all GSM PLMN. It is made of LAI and CI.CICell Identity. It is defined by carrier itselfand it is a kind of 2Byte BCD code.MCCMNCLACLAICICGI

Number Planing of GSMNumbering PlanBSICBSIC (Base Station Identity Code)It is used to identify adjacent BTS in adjacent countriesand it is a kind of 6-bit code.NCCPLMN colour code. It is used to distinguish carriers in national boundaries, also it can distinguish different provinces in one country.BCCBTS Color Code. It is distributed by carriers themselves. It is used todistinguish adjacent BTS which adopts the same type of base station.NCCBCCBSIC3bit3bit

Numbering Plan of GSMNumbering PlanIMEIIMEI (International Mobile Station Equipment Identity)IMEI is used to identify MS uniquelyand it is a 15-digit Decimal code.TACType Approval CodeFACFactory Assembly Code. It stands factory and assembly address.SNRSerial Numberit is used to identify each equipment.SP Standby CodeTACFACSNRSPIMEI6bits2bits6bits2bits

Summary of GSM Mobile CommunicationStructure of GSM SystemTheory of GSM Radio InterfaceFlow of GSM SignalNumbering Plan of GSMDevelopment of Mobile CommunicationCatalogue

Development of Mobile CommunicationDevelopment of GSM System

Development of Mobile Data ServiceDevelopment of Mobile Communicationlow-speed datahigh-speed data

The Evolving Route to 3G Development of Mobile Communication TD-SCDMA

V1.020077NSS BSSPSTN HLRVLR

NSS BSSPSTN HLRVLR

GSM Fire12

GSM13Kbit/sRPE-LTP-13kbit/s20msDTXDiscontinuous Transmission13kbit/s500bit/s480ms20ms,SID