Gsm fundamental ok

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  • This slide shows us the GSM network structure. The whole GSM network includes two parts: One is MSS; another one is BSS. Every subsystem includes some entity. For example, MSS consists of MSC/VLR …….BSS consists of …. The interface between different entity is different. Some of them is open and standard such as A, E,C,F,H.others are not.open and standard. Such as ABIS. entity : 实体 Consists of : 有…组成
  • Comprise Or consist of
  • 基站子系统 BSS 在 GSM 网络的固定部分和无线部分之间提供中继,一方面 BSS 通过无线接口直接与移动台实现通信连接,另一方面 BSS 又连接到网络端的移动交换机。
  • Protocal stack 协议堆 A interface protocal 1)Layer1 -物理层 : 定义了 MSC 和 BSC 的物理层结构,包括物理和电气参数以及信道结构。采用公共信道信令 NO.7 ( CSS7 )的消息转移部分( MTP )的第一级来实现,采用 2Mbit/s 的 PCM 数字链路作为传输链路。 2)Layer2 -数据链路层和网络层 : 网络操作程序,定义了数据链路层和网络层。 MTP2 是 HDLC (高级数据链路控制)协议的一种变体,帧结构分别由标志字段、控制字段、信息字段、校验字段和标志序列所组成。 MTP3 和 SCCP (信令连接控制部分)主要完成信令路由选择等功能。 ( 3 ) Layer3—— 应用层 主要包括 BSS 应用规程 BSSAP ,完成基站子系统的资源和连接的维护管理、业务的接续以及拆除的控制。 Abis interface protocal Layer1— 物理层 通常采用 2Mbit/sPCM 链路。 Layer2— 数据链路层 采用 LapD 协议,它为一点对多点的通讯协议,是 Q.921 规范的一个子集。 LapD 采用帧结构,包含标志字段、控制字段、信息字段、校验字段和标志序列。在标志字段中包括 SAPI (服务接入点标识)和 TEI (终端设备识别)两个部分,用以表明接入什么服务和什么实体。 Layer3— 应用层 主要传输 BTS 的应用部分,包括无线链路管理功能和操作维护功能。 Um interface protocal 传输层(或物理层): Um 接口的第一层,提供无线链路的传输通道,通过无线电波载体来传送数据,为高层提供不同功能的信道包括业务信道和逻辑信道。 ( 2 ) 数据链路层: Um 接口的第二层,为 MS 和 ZXG10-BTS ( V2 )之间提供可靠的数据链接,采用的是 LapDm 协议,它是 GSM 的专用协议,是 ISDN“D” 信道协议 LapD 的变形。 ( 3 ) 应用层: Um 接口的第三层,主要负责控制和管理的协议,把用户和系统控制过程的信息按一定的协议分组安排在指定的逻辑信道上,它包括 CM , MM 和 RR 三个子层。 CM 层:实现通信管理,在用户之间建立连接、维持和释放呼叫,可分为:呼叫控制 CC 、附加业务管理 SSM 和短消息业务 SMS 。 MM 层:实现移动性和安全性管理,移动台在发起位置更新时所做的处理。 RR 层:实现无线资源管理,在呼叫期间建立和释放移动台和 MSC 之间的连接。
  • Adopts 采用 Timeslots 时隙 Concept 概念
  • Interval 间隔
  • First, then , then Why?
  • Coexist three kind of handset The first kind support only GSM1900 provided by motorola
  • GSM 系统中,信道分成逻辑信道和物理信道。时隙是基本的物理信道,一个载频包含 8 个物理信道。物理信道支撑着逻辑信道。逻辑信道按其功能分为业务信道( TCH )和控制信道( CCH )。 业务信道携载编码语音或用户数据,它有全速率业务信道( TCH/F )和半速率业务信道( TCH/H )之分: 1 . 话音业务信道 TCH/F :全速率话音业务信道,总速率为 22.8kb/s TCH/H :半速率话音业务信道,总速率为 11.4kb/s 2 . 数据业务信道 TCH/F9.6 : 9.6kb/s 全速率数据业务信道 TCH/F4.8 : 4.8kb/s 全速率数据业务信道 TCH/H4.8 : 4.8kb/s 半速率数据业务信道 TCH/F2.4 :≤ 2.4kb/s 全速率数据业务信道 TCH/H2.4 :≤ 2.4kb/s 半速率数据业务信道 控制信道用于携载信令或同步数据,包括三类控制信道:广播信道、公共控制信道和专用控制信道。 1 . 广播信道 BCH 广播信道是一点对多点的单向下行控制信道,即基站到移动台单向传输,用于向 MS 广播各类消息,分为三种信道: ( 1 ) FCCH :频率校准信道,该信道携载有用于 MS 频率纠正的信息。 ( 2 ) SCH :同步信道,携载 MS 帧同步和基站收发信台( BTS )识别信息。 ( 3 ) BCCH :广播控制信道,用于发送小区信息。在每个基站收发信台中总有一个收发信机含有这个信道,以向该小区中所有移动台广播系统消息。 2 . 公共控制信道 CCCH 公共控制信道是一点对多点的双向控制信道,为网络中 MS 所共用,它包括三种信道: ( 1 ) PCH :寻呼信道,用于 BTS 寻呼 MS (下行信道)。 ( 2 ) RACH :随机接入信道,用于 MS 随机提出入网申请,即请求分配专用控制信道(上行信道)。 ( 3 ) AGCH :准予接入信道,用于 BTS 对 MS 的随机接入请求作出应答,即分配一专用控制信道或直接分配一个 TCH (下行信道)。 专用控制信道 专用控制信道是点对点的双向控制信道,使用时 BTS 将其分配给 MS ,进行 BTS 与 MS 之间点对点的传输。 ( 1 ) SDCCH :独立专用控制信道,用于传送信道分配等信息。 SDCCH 可分为以下几种:  SDCCH/8 :独立专用控制信道  SDCCH/4 :与 BCCH/CCCH 相组合的独立专用控制信道 ( 2 ) SACCH :慢速随路控制信道,与一条业务信道或一条 SDCCH 联合使用,用来传送用户信息期间某些特定信息,例如:功率和帧调整控制信息、测量数据等。该信道可分为以下几种:  SACCH/TF :与 TCH/F 随路的慢速随路控制信道  SACCH/TH :与 TCH/H 随路的慢速随路控制信道  SACCH/C4 :与 SDCCH/4 随路的慢速随路控制信道  SACCH/C8 :与 SDCCH/8 随路的慢速随路控制信道 ( 3 ) FACCH :快速随路控制信道,与一条业务信道联合使用,携带与 SDCCH 同样的信号,但只在没有分配 SDCCH 的情况下才分配 FACCH ,通过业务信道借取的帧(称为“偷帧”)来实现接续,传送如“越区切换”等指令。 FACCH 可分为以下几种: FACCH/F :全速率快速随路控制信道 FACCH/H :半速率快速随路控制信道 通常 TCH/F 与 SACCH 总是成对分配的, TCH/F 和 SACCH 的组合用 TACH/F 来表示。
  • Synchronous 同步
  • 广播信道 BCH 广播信道是一点对多点的单向下行控制信道,即基站到移动台单向传输,用于向 MS 广播各类消息,分为三种信道: ( 1 ) FCCH :频率校准信道,该信道携载有用于 MS 频率纠正的信息。 ( 2 ) SCH :同步信道,携载 MS 帧同步和基站收发信台( BTS )识别信息。 ( 3 ) BCCH :广播控制信道,用于发送小区信息。在每个基站收发信台中总有一个收发信机含有这个信道,以向该小区中所有移动台广播系统消息。
  • 在实际应用中,总是将不同类型的逻辑信道映射到同一物理信道上,称为信道组合。
  • 以下为 9 种信道组合类型: 1 . TCHFull TCH/F + FACCH/F + SACCH/TF 全速率业务信道 2 . TCHHalf TCH/H + FACCH/H + SACCH/TH 半速率业务信道 3 . TCHHalf2 TCH/H + FACCH/H + SACCH/TH + TCH/H 半速率 1 业务信道 4 . SDCCH SDCCH + SACCH 独立专用控制信道 5 . MainBCCH FCCH + SCH + BCCH + CCCH 主广播控制信道 6 . BCCHCombined FCCH + SCH + BCCH + CCCH + SDCCH + SACCH 组合广播控制信道 7 . BCH FCCH + SCH + BCCH 广播信道 8 . BCCHwithCBCH FCCH + SCH + BCCH + CCCH + SDCCH + SACCH + CBCH 小区广播信道 9 . SDCCHwithCBCH SDCCH + SACCH + CBCH 慢速专用控制信道 其中: ( 1 ) CCCH=PCH + RACH + AGCH 。 ( 2 ) CBCH :只有下行信道,携带小区广播信息,和 SDCCH 使用相同的物理信道。
  • 1 . 只有 1 个 TRX 的小容量蜂房的信道组合 ( 1 ) TN0 : FCCH + SCH + BCCH + CCCH + SDCCH/4 ( 0 ,…, 3 )+ SACCH/C4 ( 0 ,…, 3 ) ( 2 ) TN1~7 : TCH/F + FACCH/F + SACCH/TF 2 . 有 4 个 TRX 的中等容量蜂房 ( 1 ) 1 个 TN0 组: FCCH + SCH + BCCH + CCCH ( 2 ) 2 个 SDCCH/8 ( 0 ,…, 7 )+ SACCH/C8 ( 0 ,…, 7 ) ( 3 ) 29 个 TCH/F + FACCH/F + SACCH/TF
  • 有 12 个 TRX 的大容量蜂房 ( 1 ) 1 个 TN0 组: FCCH + SCH + BCCH + CCCH ( 2 ) 1 个 TN2 组, 1 个 TN4 组和 1 个 TN6 组: BCCH + CCCH ( 3 ) 5 个 SDCCH/8 ( 0 ,…, 7 )+ SACCH/C8 ( 0 ,…, 7 ) ( 4 ) 87 个 TCH/F + FACCH/F + SACCH/TF
  • Omni-directional 全向的 Adopt 采用 Propagation 传播 Characteristic 特征 特性 Directional 方向的
  • Coverage 有效的 覆盖 Enlarge 扩大 放大 Radius 半径 Gain 得到 增加 增进
  • Erlang 爱尔兰 Occupied 占用 Capacity 容量 Traffic intensity 话务强度 业务量强度 Defined 定义 详细说明 Block 阻塞 Queue 排队
  • Interference 冲突 干涉 extremely 极端地 unpredictable. 不可预知地 Complex 复杂的 encountering 遇到 Terrain 地形 Abrupt 突然的 Fading 衰退
  • There are many technology adopted to counteract interference.such as FH,DPC,DTX and diversity receiving techinique. Let me introduce these technique in detail. Solution 解答 transceive
  • Two things may account for the adoption of frequency hopping. First, based on the principle of frequency diversity, this technique is used to counteract Rayleigh Fading (short-term shifts in amplitude that mobile radio transmission suffers inevitably when meeting with obstacles). Different frequencies will suffer different degrees of fading, which becomes more independent with the increase in frequency difference. By means of frequency hopping, all the burst pulses containing part of the code elements will not be damaged in the same way. Second, based on the characteristics of interference sources. In areas where traffic is heavy, the cellular system is liable to be restricted by the interference from frequency multiplexing. The ratio of carrier to interference C/I changes a lot during the call). “ C ” is determined by the relative location of MS in reference to BS, “ I ” depends on whether this frequency is used in the adjacent cell The introduction of frequency hopping makes it possible to scatter interference among multiple calls that may interfere cells instead of centralizing it on one call. Frequency hopping refers to the hop of carrier frequency according to certain sequences within a wide spectrum. Data of control information are converted into base band signals after modulation, which are then sent into carrier wave modulation. Afterwards, the carrier frequency changes under the control of pseudo-associated codes, the sequence of which is frequency hopping sequence. Finally, FH sequences are sent via radio frequency filter to antenna for transmission. The receiver determines the receiving frequency according to synchronization signals and FH sequence by receiving corresponding signals after FH for demodulation. Special features of FH techniques: working bands within the system can be increased by adopting FH, thus enhancing the system ’ s anti-interference and anti-fading capabilities. By FH, BP of the effective information part will be improved and protected from being influenced by Rayleigh fading in the communication environment. Via FH, the original data can be retrieved from channel decoding, and the increase in FH numbers may enhance FH gain, consequently improving anti-interference and anti-fading capabilities of the system. Virtually, frequency hopping is to avoid external interference. In other words, it is to prevent or greatly reduce co-channel interference and frequency selective fading effect by converting frequencies to an extent that interference cannot catch up with them. The increase of FH number is due to the fact that FH system gain equals to the ratio of FH system bandwidth to N minimum FH intervals. Therefore, the increase of FH also improves FH gain. Commonly adopted FH numbers should be greater than 3. If frequency diversity is plus FH and the message is decided more effectively via a large number decision law after several groups of FH simultaneously transmits one, more subscribers work at the same time but mutual interference is the least. Two types of frequency hopping exist in ZXG10, base band frequency hopping and radio frequency hopping. 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. However, radio frequency hopping is to control the frequency synthesizer of each transceiver, making it hop according to different schemes in different time slots.
  • There are two speech transmission modes: 1) No matter whether the subscriber speaks or not, continuous speech encoding is carried out (a speech frame/20ms) ; 2) DTX (Discontinuous Transmission) performs 13kbit/s encoding during voice activity and 500bit/s encoding during non-voice activation. At a rate of very 480ms one frame (20ms each frame) is transmitted. However, merely the comfort noise is transmitted .
  • ( 垂直 )
  • In a sense
  • Gsm fundamental ok

    1. 1. GSM Fundamental By Uke Kurniawan Usman1 Uke Kurniawan Usman - 2005
    2. 2. Agenda  Network Architecture  Functional Layer of GSM  Air Interface  System Capacity  Anti Interference Technology  Network Planning  Numbering arrangement2 Uke Kurniawan Usman - 2005
    3. 3. GSM Network Structure OMC MSC/VLR BSC E BIE Abi A PSTN BTS s MSC/VLR ISDN BSS PSPDN C Um F H HLR/ AUC EIR SC/VM MS MSS3 Uke Kurniawan Usman - 2005
    4. 4. Mobile Station ( MS ) Equipment used by mobile service subscribers for access to services. Mobile Equipment Subscriber Identity Module (SIM) Mobile stations are not fixed to one subscriber. A subscriber is identified with the SIM card.4 Uke Kurniawan Usman - 2005
    5. 5. GSM Network Entity Base Transceiver Station ( BTS ) 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 maintenance5 Uke Kurniawan Usman - 2005
    6. 6. GSM Network Entity Base Station Controller ( BSC ) 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.6 Uke Kurniawan Usman - 2005
    7. 7. GSM Network Entity Mobile Service Switching Center ( MSC ) 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).7 Uke Kurniawan Usman - 2005
    8. 8. GSM Network Entity Home Location Register ( HLR ) 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 address8 Uke Kurniawan Usman - 2005
    9. 9. GSM Network Entity 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 parameters9 Uke Kurniawan Usman - 2005
    10. 10. GSM Network Entity 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 Identity10 Uke Kurniawan Usman - 2005
    11. 11. Agenda  Network Architecture  Functional Layer of GSM  Air Interface  System Capacity  Anti Interference Technology  Network Planning  Numbering arrangement11 Uke Kurniawan Usman - 2005
    12. 12. Overview: Function Layers of GSM-1 S ervice carrie r O AM Subsc riber CM MM RR Tran smissi on12 Uke Kurniawan Usman - 2005
    13. 13. Protocol Stack Structure of GSM MS BTS BSC M SC CM CM MM MM RR BS SAP BS SAP RR RR BTSM BTSM SCCP SCCP MT P3 MTP3 L APDm LAP Dm LAPD LAPD MT P2 MTP2 Um Abis A13 Uke Kurniawan Usman - 2005
    14. 14. Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement14 Uke Kurniawan Usman - 2005
    15. 15. TDMA time Concept: User 3 channel is composed of a series of timeslots of User 2 periodicity. Different signal User 1 energies are distributed into different timeslots. The Frequency adjacent channel interference is restricted by connection GSM adopts TDMA/FDMA mode choosing from time to time. So channel width: 200KHz the useful signal is passed each channel has 8 timeslots only in the specified timeslot.15 Uke Kurniawan Usman - 2005
    16. 16. GSM Timeslot and Frame structure Frequency 200KHz BP time 15/26ms interval16 Uke Kurniawan Usman - 2005
    17. 17. Frequency Resource GSM900 : EGSM900 : up: 890~915MHz up: 880~890MHz down: 935~960MHz down: 925~935MHz duplex interval: 45MHz duplex interval: 45MHz bandwidth: 25MHz , bandwidth: 10MHz , frequency interval: 200KHz frequency interval: 200KHz GSM1800 : GSM1900MHz: up: 1710-1785MHz up:1850~1910MHz down: 1805-1880MHz down:1930~1990MHz duplex interval: 95MHz , duplex interval: 80MHz , working bandwidth: 75MHz , working bandwidth: frequency interval: 200KHz 60MHz ,17 frequency interval: Usman - 2005 Uke Kurniawan 200KHz
    18. 18. Frequency Resource Single Band Network General Priority Which one? 900MHz High 1800MHz 1900MHz Low New Operator Reason Propagation Characteristic For Operator For Subscriber18 Uke Kurniawan Usman - 2005
    19. 19. Frequency Resource Single Band Network Single Band 900MHz Dual Band 1800MHz Triple Band 1900MHz In a sense, the network determines the handsets can be selected. But nowadays, most handsets support dual19 band. Uke Kurniawan Usman - 2005
    20. 20. Frequency Resource Single Band Network Cell coverage radius : We know Propagation characteristic The higher the propagation frequency 900MHz 1800MHz The higher the propagation loss 1900MHz The smaller the cell coverage radius.20 Uke Kurniawan Usman - 2005
    21. 21. Timeslot and Frame structure 1 super high frame = 2048 super frame = 2715648 TDMA frame 0 1 2 3 2044 2045 2046 2047 BCCH 1 super frame = 1326 TDMA frame ( 6.12s ) CCCHSACCH/TCH SDCH FACCH 0 1 2 3 47 48 49 50 0 1 24 25 1 multiplex frame = 26 TDMA frames ( 120ms ) 1 multiplex frame = 51 TDMA frame 0 1 24 25 0 1 49 50 1 TDMA frame = 8 timeslot ( 120/26 = 4.615ms ) 0 1 2 3 4 5 6 7 21 Uke Kurniawan Usman - 2005
    22. 22. Physical Channel 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 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.22 Uke Kurniawan Usman - 2005
    23. 23. Channel Type-Summary 14.4Kbit/s FR TCH (TCH/F14.4) 9.6Kbit/s FR TCH(TCH/F9.6) Data CH 4.8Kbit/s FR TCH (TCH/F4.8) TCH 4.8Kbit/s HR TCH (TCH/H4.8) FR Voice Traffic Channel (TCH/FS) Voice CH Enhanced FR Traffic Channel (TCH/EFR) HR Traffic Channel (TCH/HS) channel FCCH (down) SCH (down) BCH BCCH (down) RACH (up) CCH CCCH AGCH (down) PCH (down) SDCCH DCCH FACCH SACCH23 Uke Kurniawan Usman - 2005
    24. 24. Channel Type Traffic Channel Transmit voice and data Signaling Channel transmit the signaling and synchronous data between BTS and MS.24 Uke Kurniawan Usman - 2005
    25. 25. 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..)25 Uke Kurniawan Usman - 2005
    26. 26. 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.26 Uke Kurniawan Usman - 2005
    27. 27. Structure of 51-frame Control CH 51 Frame BCCH+CCCH F S B C F S C C F S C C F S C C F S C C I (Downlink) BCCH+CCCH RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR (uplink) (a) FCCH+SCH+BCCH+CCCH 8 SDCCH/8 D0 D1 D2 D3 D4 D5 D6 D7 A0 A1 A2 A3 I I I (Downlink) D0 D1 D2 D3 D4 D5 D6 D7 A4 A5 A6 A7 I I I 8 SDCCH/8 A1 A2 A3 I I I D0 D1 D2 D3 D4 D5 D6 D7 A0 (uplink) A5 A6 A7 I I I D0 D1 D2 D3 D4 D5 D6 D7 A4 (b) SDCCH/8(0,...,7)+SACCH/C8(0,...,7) BCCH+CCCH+ F S B C F S C C F S D0 D1 F S D2 D3 F S A0 A1 I 4SDCCH/4 (Downlink) F S B C F S C C F S D0 D1 F S D2 D3 F S A2 A3 I BCCH+CCCH+ D3 RR A2 A3 RRRRRRRRRRRRRRRRRRRRRRR D0 D1 F S D2 4SDCCH/4 (uplink) D3 RR A0 A1 RRRRRRRRRRRRRRRRRRRRRRR D0 D1 F S D2 (c) FCCH+SCH+CCCH+SDCCH/4(0,...,3)+SACCH/C4(0,...,3) F:FCCH S:SCH B:BCCH C:CCCH(CCCH=PCH+AGCH+RACH) R:RACH D:SDCCH27 A:SACCH/C I: idle Uke Kurniawan Usman - 2005
    28. 28. 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: a TCH/F + FACCH/F + SACCH/TF b TCH/H(0,1) + FACCH/H(0,1) + SACCH/TH(0,1) c TCH/H(0,0) + FACCH/H(0,1) + SACCH/TH(0,1) + TCH/H(1,1) d FCCH + SCH + BCCH + CCCH e FCCH + SCH + BCCH + CCCH + SDCCH/4(0...3) + SACCH/C4(0...3) f BCCH + CCCH g SDCCH/8(0 ..7) + SACCH/C8(0 .. 7) CCCH = PCH + RACH + AGCH28 Uke Kurniawan Usman - 2005
    29. 29. Channel Assignment inside cells  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/TF29 Uke Kurniawan Usman - 2005
    30. 30. Channel Assignment inside cells  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/TF30 Uke Kurniawan Usman - 2005
    31. 31. Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement31 Uke Kurniawan Usman - 2005
    32. 32. Cell Mode Layout Omni-directional cell O 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.32 Uke Kurniawan Usman - 2005
    33. 33. BTS Mode  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.33 Uke Kurniawan Usman - 2005
    34. 34. System capacity 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.34 Uke Kurniawan Usman - 2005
    35. 35. Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement35 Uke Kurniawan Usman - 2005
    36. 36. 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.36 Uke Kurniawan Usman - 2005
    37. 37. 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.37 Uke Kurniawan Usman - 2005
    38. 38. Interference 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 ensure38 adequate isolation of transmissions.  Usman - 2005 Uke Kurniawan
    39. 39. Interference  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/A39 Uke Kurniawan Usman - 2005
    40. 40. Solution -Anti-interference  FH technology  Dynamic power control (DPC)  Discontinuous Transceiving (DTX)  Diversity receiving technique40 Uke Kurniawan Usman - 2005
    41. 41. Frequency Hopping Technique 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 time41 slots. Uke Kurniawan Usman - 2005
    42. 42. Discontinuous Speech Transmission (DTX) Two aims can be achieved by adopting DTX mode: •lower the total interference electric level in the air •save transmitter power. TRAU BTS BTS MS 480 ms comfort noise frame Speech frame42 Uke Kurniawan Usman - 2005
    43. 43. Diversity Reception Technology 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.43 Uke Kurniawan Usman - 2005
    44. 44. Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement44 Uke Kurniawan Usman - 2005
    45. 45. Frequency Reuse D3 A1 C2 C3 B1 D2 C1 A2 A3 D1 B2 B3 C1 C3 B1 D2 D3 A1 C2 C3 A1 B2 B3 C1 A2 A3 D1 D2 A1 C2 C3 B1 D2 A1 D3 “4 × 3” reuse mode: one group includes 3 sectors /site ,12 frequency which are distributed to 4 sites. Every site owns 3 frequency.45 Uke Kurniawan Usman - 2005
    46. 46. Frequency Reuse B3 A1 B2 B3 A1 B2 C1 A2 A3 C1 A2 A3 C1 C3 B1 C2 C3 B1 C2 C3 A1 B2 B3 A1 B2 B3 A1 A3 C1 A2 A3 C1 A2 A1 A3 “3 × 3” reuse mode: one group includes 3 sectors /site ,9 frequency which are distributed to 3 sites. Every site owns 3 frequency.46 Uke Kurniawan Usman - 2005
    47. 47. Agenda Network Architecture Functional Layer of GSM Air Interface System Capacity Anti Interference Technology Network Planning Numbering arrangement47 Uke Kurniawan Usman - 2005
    48. 48. 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, 460 2 ) 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 by48 specific device and software and be stored into the HLR - 2005 Uke Kurniawan Usman
    49. 49. Numbering Arrangement Mobile Subscriber ISDN Number ( MSISDN ) 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 number49 inside each HLR Uke Kurniawan Usman - 2005
    50. 50. Numbering Arrangement 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 digit50 Uke Kurniawan Usman - 2005
    51. 51. Numbering Arrangement 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 + 00 + M1M2M3 + ABC    CC: country code, 86     NDC: mobile network code, 135—139, 130    M1M2: same as the H2H3 of MSISDN    ABC: 000 -- 99951 Uke Kurniawan Usman - 2005
    52. 52. Numbering Arrangement 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.52 Uke Kurniawan Usman - 2005

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