Oct 09, 2015
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
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