Uke Kurniawan Usman GSM Fundamental By Uke Kurniawan Usman

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman MSC/VLR HLR/ AUC EIR SC/VM OMC BSC BTS PSTN ISDN PSPDN MS BSS MSS Um Abi s BIE A F C H MSC/VLR E GSM Network Structure

Uke Kurniawan Usman Equipment used by mobile service subscribers for access to services. Mobile Station ( MS ) Mobile Equipment Subscriber Identity Module (SIM) Mobile stations are not fixed to one subscriber. A subscriber is identified with the SIM card.

Uke Kurniawan Usman Base Transceiver Station (BTS) Wireless transmission Wireless diversity Wireless channel encryption Conversion between wired and wireless signals Frequency Hopping  BaseBand Unit: voice and data speed adapting and channel coding  RF Unit: modulating/demodulating, transmitter and receiver  Common Control Unit: BTS operation and maintenance GSM Network Entity Base Transceiver Station ( BTS )

Uke Kurniawan Usman Managing Wireless network-BSS Monitoring BTS Controls: Wireless link distribution between MS and BTS Communication connection and disconnection MS location, handover and paging Voice encoding, transecoding (TC), rate, adaptation, The operation and maintenance functions of BSS. Base Station Controller ( BSC ) GSM Network Entity

Uke Kurniawan Usman  holds all the switching functions  manages the necessary radio resources, updating the location registration carrying out the inter-BSC and inter-MSC tender  Inter-working with other networks (IWF). GSM Network Entity Mobile Service Switching Center ( MSC )

Uke Kurniawan Usman Manages the mobile subscribers database  subscriber information  part of the mobile location information  3 identities essential the International Mobile subscriber Identity the Mobile station ISDN Number the VLR address GSM Network Entity Home Location Register ( HLR )

Uke Kurniawan Usman Visitor Location Register ( VLR ) dynamically stores subscriber information needed to handle incoming/outgoing calls  Mobile Station Roaming Number When a roaming mobile enters an MSC area. This MSC warns the associated VLR of this situation; the mobile enters a registration procedure through which it is assigned a mobile subscriber roaming number (MSRN)  Temporary Mobile Subscriber Identity, if applicable  The location area in which the mobile has been registered  Data related to supplementary service parameters GSM Network Entity

Uke Kurniawan Usman AUC/EIR Authentication Center(s) (AUC) Providing the authentication key used for authorizing the subscriber access to the associated GSM PLMN. Equipment Identity Register(s) (EIR) Handling Mobile Station Equipment Identity GSM Network Entity

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman Overview: Function Layers of GSM-1

Uke Kurniawan Usman Protocol Stack Structure of GSM

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman Concept: channel is composed of a series of timeslots of periodicity. Different signal energies are distributed into different timeslots. The adjacent channel interference is restricted by connection choosing from time to time. So the useful signal is passed only in the specified timeslot. GSM adopts TDMA/FDMA mode channel width: 200KHz each channel has 8 timeslots GSM adopts TDMA/FDMA mode channel width: 200KHz each channel has 8 timeslots User 1 User 2 User 3 Frequency time TDMA

Uke Kurniawan Usman GSM Timeslot and Frame structure time Frequency BP 15/26ms 200KHz interval

Uke Kurniawan Usman Frequency Resource GSM900 : up: 890~915MHz down: 935~960MHz duplex interval: 45MHz bandwidth: 25MHz ， frequency interval: 200KHz GSM1800 : up: MHz down: MHz duplex interval: 95MHz ， working bandwidth: 75MHz ， frequency interval: 200KHz EGSM900 : up: 880~890MHz down: 925~935MHz duplex interval: 45MHz bandwidth: 10MHz ， frequency interval: 200KHz GSM1900MHz: up:1850~1910MHz down:1930~1990MHz duplex interval: 80MHz ， working bandwidth: 60MHz ， frequency interval: 200KHz

Uke Kurniawan Usman MHz 1900MHz 900MHz Which one? Single Band Network General Priority High Low Reason For Subscriber For Operator Propagation Characteristic New Operator Frequency Resource

Uke Kurniawan Usman MHz 1900MHz 900MHz Single Band Network Single Band Dual Band Triple Band In a sense, the network determines the handsets can be selected. But nowadays, most handsets support dual band. Frequency Resource

Uke Kurniawan Usman Propagation characteristic Cell coverage radius : The higher the propagation frequency The higher the propagation loss The smaller the cell coverage radius. 900MHz 1800MHz 1900MH z Single Band Network Frequency Resource We know

Uke Kurniawan Usman super high frame = 2048 super frame = TDMA frame 1 super frame = 1326 TDMA frame （ 6.12s ） multiplex frame = 26 TDMA frames （ 120ms ） 1 multiplex frame = 51 TDMA frame TDMA frame = 8 timeslot （ 120/26 = 4.615ms ） BCCH CCCH SDCH SACCH/TCH FACCH Timeslot and Frame structure

Uke Kurniawan Usman The physical channel adopts FDMA and TDMA techs. On the time domain, a specified channel occupies the same timeslots in each TDMA frame, so it can be identified by the timeslot number and frame number. Physical Channel

Uke Kurniawan Usman channel TCH CCH Voice CH Data CH FR Voice Traffic Channel (TCH/FS) HR Traffic Channel (TCH/HS) 4.8Kbit/s HR TCH (TCH/H4.8) 9.6Kbit/s FR TCH(TCH/F9.6) 4.8Kbit/s FR TCH (TCH/F4.8) BCH FCCH (down) SCH (down) BCCH (down) CCCH RACH (up) AGCH (down) PCH (down) DCCH SDCCH FACCH SACCH 14.4Kbit/s FR TCH (TCH/F14.4) Enhanced FR Traffic Channel (TCH/EFR) Channel Type-Summary

Uke Kurniawan Usman Channel Type Traffic Channel Transmit voice and data Signaling Channel transmit the signaling and synchronous data between BTS and MS.

Uke Kurniawan Usman Channel Type BCH : Frequency Correction CHannel （ FCCH ） -- for MS error correction Synchronous Channel （ SCH) -- for MS frame synchronization and BTS recognization Broadcasting Control CHannel （ BCCH ） -- broadcasting information(cell selection information, etc..)

Uke Kurniawan Usman Channel Type DCCH Self-help Dedicated Control Channel （ SDCCH ） for channel distribution information transmission Slow Associated Control Channel （ SACCH ） combined with one traffic channel or SDCCH, to transmit some specific information of user information Fast Associated Control Channel （ FACCH ） combined with one traffic channel, taking the same signal as SDCCH. It occupies the service channel to transmit signaling information.

Uke Kurniawan Usman Structure of 51-frame Control CH

Uke Kurniawan Usman Channel Combination Type Several logic channels combine together in some way to form some specific types of channel to transmit user data or signaling information. They are called combined channels. One combined channel can be mapped to a physical channel. There are the following combined channels: aTCH/F + FACCH/F + SACCH/TF bTCH/H(0,1) + FACCH/H(0,1) + SACCH/TH(0,1) cTCH/H(0,0) + FACCH/H(0,1) + SACCH/TH(0,1) + TCH/H(1,1) dFCCH + SCH + BCCH + CCCH eFCCH + SCH + BCCH + CCCH + SDCCH/4(0...3) + SACCH/C4(0...3) fBCCH + CCCH gSDCCH/8(0..7) + SACCH/C8(0.. 7) CCCH = PCH + RACH + AGCH

Uke Kurniawan Usman Small capacity cell with only 1 TRX TN0: FCCH+SCH+CCCH+BCCH+SDCCH/4(0,_,3)+SACCH/C4(0,_,3); TN1-7: TCH/F+FACCH/F+SACCH/TF The medium-size cell with 4 TRXs 1TN0 group: FCCH+SCH+BCCH+CCCH; 2 SDCCH/8(0,_,7)+SACCH/C8(0,_,7); 29 TCH/F+FACCH/F+SACCH/TF Channel Assignment inside cells

Uke Kurniawan Usman Large-size cell with 12 TRXs 1 TN0 group: FCCH+SCH+BCCH+CCCH; 1 TN2 group, 1 TN4 group and 1 TN6 group: BCCH+CCCH; 5 SDCCH/8(0,_,7)+SACCH/C8(0,_,7); 87 TCH/F+FACCH/F+SACCH/TF Channel Assignment inside cells

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman Cell Mode Layout Omni-directional cell Adopt omni-directional antenna ， the overall directional propagation characteristic is the same. Directional cell In general, cell with multi-sector is in common use. Every directional cell adopts directional antenna.

Uke Kurniawan Usman  Capacity When the traffic is very low, and no possibility for quick increment, Omni-directional cell is used in common. Otherwise, we suggest to adopt the sector cell. Note: TRX-transceiver,each TRX handles 1 frequency.  Coverage Area Sector cell is often used to enlarge the cell coverage radius because of the higher antenna gain. For special coverage,such as road coverage, two-sector cell is adopted firstly. BTS Mode

Uke Kurniawan Usman Erlang : the traffic intensity of a totally occupied channel (i.e. the call hour of a unit hour or the call minute of a unit minute). For example, the traffic of a channel occupied for 30 minutes in an hour is 0.5 Erlang) GOS: defined as the probability of call blocking or the probability when the call delay time is longer than a given queuing time. System capacity

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman Reasons for Interference The transmission path is very complex, ranging from the simple line-of-sight transmission to encountering such terrain as buildings, hills and trees. Wireless channels are extremely unpredictable. Abrupt drop, or fading, of signal strength in the land mobile wireless channel is quite common. The fading feature of the mobile channel depends on the radio wave propagation environment.

Uke Kurniawan Usman Reasons for interference Environmental factors: Terrain (mountains, hills, plains, water bodies, etc.); The quantity, heights, distribution and materials of buildings; The vegetation of the region; Weather conditions; Natural and artificial electromagnetic noises; Frequency; How MS is moved.

Uke Kurniawan Usman  Co-Channel Interference Conception: the interference among the signals of co- channel cells is called co-channel interference. Result from : Frequency reuse Reduction method: co-channel cells must physically be spaced at a minimum interval to ensure adequate isolation of transmissions. Interference

Uke Kurniawan Usman  Adjacent Channel Interference Conception: The signal interference from the frequency adjacent to that of the signal used is called adjacent channel interference. Reduction method: accurate filtering and channel allocation (maximizing channel intervals of the cell). Interval of frequency reuse inter-cell interference, such as C/I, C/A Interference

Uke Kurniawan Usman FH technology Dynamic power control (DPC) Discontinuous Transceiving (DTX) Diversity receiving technique Solution -Anti-interference

Uke Kurniawan Usman Reason: counteract Rayleigh Fading scatter interference among multiple calls Types:  Base band frequency hopping keeps the transmission and receiving frequency of each carrier unit unchanged, but merely sends FU transmission data to different carrier units at different FN moments.  radio frequency hopping controls the frequency synthesizer of each transceiver, making it hop according to different schemes in different time slots. Frequency Hopping Technique

Uke Kurniawan Usman Discontinuous Speech Transmission (DTX)  TRAU BTS  BTS MS Speech frame  480 ms comfort noise frame Two aims can be achieved by adopting DTX mode: lower the total interference electric level in the air save transmitter power.

Uke Kurniawan Usman The multi-path propagation of radio signals causes magnitude fading and delay time.  Space Diversity (antenna diversity)  Polarization Diversity orthogonal polarization diversity. horizontal polarization and vertical polarization.  Frequency Diversity The working principle of this technology is that such fading won’t take place on the frequency outside the coherence bandwidth of the channel. Diversity Reception Technology

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman “4  3” reuse mode: one group includes 3 sectors /site,12 frequency which are distributed to 4 sites. Every site owns 3 frequency. Frequency Reuse

Uke Kurniawan Usman Frequency Reuse “3  3” reuse mode: one group includes 3 sectors /site,9 frequency which are distributed to 3 sites. Every site owns 3 frequency.

Uke Kurniawan Usman Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement

Uke Kurniawan Usman Numbering Arrangement International Mobile Subscriber Identification number (IMSI) It identifies a unique international universal number of a mobile subscriber, which consists of MCC+MNC+MSIN. 1) MCC: country code, ） MNC: network code, 00 or 01 3 ） MSIN: subscriber identification, H1H2H3H4 9XXXXXX, H1H2H3H4: subscriber registering place H1H2: assigned by the P&T Administrative Bureau (operator )to different provinces, to each province H3H4: assigned by each province/city the IMSI of user will be written into the SIM card by specific device and software and be stored into the HLR with other user information.

Uke Kurniawan Usman It is the subscriber number commonly used. China uses the TDMA independent numbering plan: CC+NDC+ H1H2H3H4 +ABC CC: country code, 86 NDC: network code, 135—139, 130 H1H2H3H4: HLR identification code ABCD: mobile subscriber number inside each HLR Mobile Subscriber ISDN Number （ MSISDN ） Numbering Arrangement

Uke Kurniawan Usman International Mobile Equipment Identification code (IMEI) International Mobile Equipment Identification code (IMEI) It will uniquely identify a mobile station. It is a decimal number of 15 digits. Its structure is: TAC+FAC+SNR+SP TAC=model ratification code, 6 digits FAC=factory assembling code, 2 digits SNR=sequence code, 6 digits SP=reserved, 1 digit Numbering Arrangement

Uke Kurniawan Usman Mobile Subscriber Roaming Number (MSRN) The MSRN is temporarily distributed to the subscriber by the VLR according to the request by the HLR when this subscriber is called. The MSRN is released and can be assigned to other subscriber later. CC + NDC M1M2M3 + ABC CC: country code, 86 NDC: mobile network code, 135—139, 130 M1M2: same as the H2H3 of MSISDN ABC: Numbering Arrangement

Uke Kurniawan Usman Temporarily Mobile Subscriber Identification Number (TMSI) Temporarily Mobile Subscriber Identification Number (TMSI) To insure the IMSI security, the VLR will assign an unique TMSI number for the accessed subscriber. It is used locally only and is a 4-byte TMSI number BCD code. Numbering Arrangement