摘 要

　　　從第一代模擬移動(dòng)通信系統(tǒng)到目前的第三代數(shù)字移動(dòng)通信系統(tǒng)，蜂窩移動(dòng)通信已經(jīng)歷了20余年的發(fā)展歷程。作為歐洲一個(gè)數(shù)字蜂窩移動(dòng)通信標(biāo)準(zhǔn)的GSM系統(tǒng)于1991年正式在歐洲面世，由于其公開的規(guī)范標(biāo)準(zhǔn)以及強(qiáng)大的漫游能力，從而獲得了空前的發(fā)展。

　　　本課題主要任務(wù)是用C語言對(duì)基于TCH/FS信道的GSM系統(tǒng)進(jìn)行仿真，由于移動(dòng)無線信道受到各種干擾、多徑衰落和陰影衰落等影響，對(duì)于數(shù)字和數(shù)據(jù)信號(hào)的傳輸，會(huì)造成突發(fā)性誤碼和隨機(jī)性錯(cuò)誤。為了解決無線信道傳輸帶來的問題，從原始的用戶數(shù)據(jù)到無線電波所攜帶的信息，再還原成用戶數(shù)據(jù)，需要進(jìn)行一系列的變換和反變換，實(shí)現(xiàn)對(duì)所傳輸信號(hào)的必要保護(hù)。這些變換大致包括：信源編碼與解碼、信道編碼與解碼、交織與解交織、調(diào)制以及均衡等模塊。本課題在對(duì)上述各模塊依次進(jìn)行仿真時(shí)，依據(jù)協(xié)議GSM05.03的編碼方案對(duì)數(shù)據(jù)進(jìn)行編碼,除采用新型的信源編碼技術(shù)外，還采用檢、糾錯(cuò)信息編碼以及信道編碼保護(hù)的交織重排等手段，以提高傳輸效果和通信質(zhì)量。同時(shí)采用GMSK調(diào)制、信道均衡和Viterbi譯碼等處理方法，來獲得在不同信道模型下（AWGN、GSM HTx和GSM EQx模型）的不同信噪比Eb/N0的編碼性能。


 




　　　關(guān)鍵詞：GSM  卷積碼  交織  GMSK調(diào)制  MLSE均衡  Viterbi譯碼


 


 


 


 


 




Abstract

　　　　From the first generation of analog mobile communication system to the third digital mobile communication system, the cellular mobile communication technology has developed for more than 20 years. As one of cellular digital communication system standards, GSM system was published formally in Europe in 1991, and acquired an unprecedented development because of its public criterion and powerful ability of roaming.

　　　　This thesis is about the simulation of GSM system based on TCH/FS Channel by C language ,However, the various interferences, multipath  fading and shadow fading in wireless communication system , will result in the abrupt error code and random mistakes. In order to resolve the problems bringed from wireless channel, from primal user’s data to information the wireless electric wave takes, then to recover primal user’s data, there needs a series of transformations and contra-transformations to implement the necessary protection of the transferred signals.These transformations contain: Information source coding and decoding, Information channel coding and decoding, interleaving and deinterleaving, modulation and equalization and so on.

　　　　When the transmission and reception of Normal Burst is simulated, the thesis uses the coding algorithm according to the GSM05.03. In addition to the newly source coding technology, the thesis also uses error detecting  and error correction coding and channel coding to heighten the communication quality. What’s more, it adopts the GMSK modulation, channel equalization and Viterbi encoding to acquire the performance under different SNR.




　　　　Key words：GSM   convolutional-code   interleaving   GMSK-modulation

                 MLSE-equalization  Viterbi-decoding


 




目  錄

摘 要 I

Abstract II

目  錄 III

第1章  GSM系統(tǒng)概述 1

1.1  GSM系統(tǒng)的發(fā)展史 1

1.1.1  GSM數(shù)字移動(dòng)通信的發(fā)展 1

1.1.2  GPRS的發(fā)展 2

1.1.3  向3G演進(jìn)之路 3

1.2  GSM系統(tǒng)的特點(diǎn) 3

1.3  GSM系統(tǒng)的業(yè)務(wù)功能 4

1.3.1  承載業(yè)務(wù) 4

1.3.2  用戶業(yè)務(wù) 4

1.3.3  補(bǔ)充業(yè)務(wù) 5

1.4  本文內(nèi)容安排 5

第2章  GSM系統(tǒng)無線接口與無線傳輸 6

2.1  GSM頻段劃分 6

2.2  GSM多址技術(shù) 6

2.2.1  頻分多址 7

2.2.2  時(shí)分多址 7

2.2.3  TDMA幀 7

2.2.4  突發(fā)脈沖（Burst） 8

2.3  TDMA信道 10

2.3.1  業(yè)務(wù)信道 10

2.3.2  控制信道 11

2.4  電波傳輸特點(diǎn) 11

2.4.1  傳輸損耗 11

2.4.2  陰影效應(yīng) 11

2.4.3  多徑效應(yīng) 12

2.4.4  時(shí)間調(diào)整 12

第3章  GSM系統(tǒng)各模塊仿真設(shè)計(jì) 14

3.1  GSM系統(tǒng)仿真設(shè)計(jì)流程 14

3.2  GSM系統(tǒng)信源模塊設(shè)計(jì) 15

3.2.1  工作原理和功能設(shè)計(jì) 15

3.2.2  接口描述和模塊實(shí)現(xiàn) 15

3.2.3  性能測(cè)試 16

3.3  GSM系統(tǒng)信道編碼模塊設(shè)計(jì) 17

3.3.1  工作原理和功能設(shè)計(jì) 17

3.3.2  接口描述和模塊實(shí)現(xiàn) 17

3.3.3  性能測(cè)試 19

3.4  GSM系統(tǒng)交織、映射設(shè)計(jì) 20

3.4.1  工作原理和功能設(shè)計(jì) 20

3.4.2  接口描述和模塊實(shí)現(xiàn) 21

3.4.3  性能測(cè)試 23

3.5  GSM系統(tǒng)調(diào)制模塊設(shè)計(jì) 23

3.5.1  工作原理和功能設(shè)計(jì) 23

3.5.2  接口描述和模塊實(shí)..