電信認(rèn)證cdma原理基礎(chǔ)知識(shí)(2)(參考版)
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【正文】 Repetition Block Interleaver Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 反向信道解調(diào) ? IS95A/JSTD008移動(dòng)臺(tái)調(diào)制過程的反過程 ? 多徑分量有益于 CDMA處理 ? 來自多個(gè)接收單元的信號(hào)可以被矢量合并以改善總的接收信號(hào)質(zhì)量 U/D Command DeInterleaver Speech Output Combiner BTS Receiver BSC Demodulator Search Correlator Demodulator Search Correlator Demodulator Search Correlator Demodulator Search Correlator Power Control Decision Viterbi Decoder 聲碼器 Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) CDMA概述 第四課 : CDMA反向信道 4a: 反向業(yè)務(wù)信道 復(fù)習(xí) Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 4a: Review Questions 1. What is the size of the block interleaving arrays used in the Reverse CDMA Channels? Their size is 32 rows by 18 columns (576 modulation symbols). 2. What is the modulation symbol rate input to the Orthogonal Modulation step, what is the chip rate out, and how does this rate change happen? ksps in, kcps out. Every six modulation symbols are interpreted as a Walsh index (063), and they are replaced by the corresponding 64bit Walsh code. Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) CDMA概述 第四課 : CDMA反向信道 4b: 接入信道 Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 4b: 接入信道 課程目標(biāo) ? 論述接入信道的作用 ?明確接入信道的主要調(diào)制參數(shù) ?了解接入信道的產(chǎn)生 ?了解接入信道和尋呼信道的關(guān)系 Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 接入信道 ? 移動(dòng)臺(tái)用接入信道： ? 與基站建立初始通信 ? 對(duì)尋呼信道消息作出響應(yīng) ?固定數(shù)據(jù)率： 4800bps ?每個(gè)接入信道僅與一個(gè)尋呼信道相關(guān) ?每個(gè)尋呼信道最多可支持 32個(gè)接入信道 (031) 4800 bps Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 接入信道的生成 ? 請(qǐng)求消息被隨機(jī)化以降低沖突的可能性 ?兩類消息 : ? 響應(yīng)消息 (響應(yīng)基站的消息 ) ? 請(qǐng)求消息 (移動(dòng)臺(tái)自動(dòng)發(fā)送 ) ksps Convolutional Encoder amp。 Symbol Repetition ? 20ms符號(hào)塊被按序重新排列 ?抵抗快衰落的影響 ?4800bps和 4800bps以下速率的重復(fù)符號(hào)被隔離開來 ? 改善了符號(hào)數(shù)據(jù)對(duì)衰落的抵抗性能 ? 分散了突發(fā)干擾的影響 輸入陣列 (正常序列 ) 32 x 18 輸出陣列 (重排序序列 ) 32 x 18 ksps to Orthogonal Modulation Course 809 Lesson 4: CDMA反向信道 Issue (January 1998) 反向業(yè)務(wù)信道： 64階正交調(diào)制 ? 每輸入六個(gè)符號(hào)，輸出 64個(gè)沃氏比特片 ? 六個(gè)符號(hào)被轉(zhuǎn)換為一個(gè) 063的十進(jìn)制數(shù) ? 對(duì)應(yīng)該數(shù)的 64位沃氏碼被輸出 1 0 1 1 0 0 1 0 0 0 1 1 Symbols 35 44 Walsh Lookup Table W a ls h C h ip w i t h i n a W a l sh F u n c t io n0 1 2 3 4 5 6 7 1 18 9 0 11 1 1 12 3 4 51 1 1 16 7 8 92 2 2 20 1 2 32 2 2 24 5 6 72 2 3 38 9 0 13 3 3 32 3 4 53 3 3 36 7 8 94 4 4 40 1 2 34 4 4 44 5 6 74 4 5 58 9 0 15 5 5 52 3 4 55 5 5 56 7 8 96 6 6 60 1 2 301230 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 00 0 0 00 1 0 10 0 1 10 1 1 045670 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0 0 00 1 0 10 0 1 10 1 1 01 1 1 11 0 1 01 1 0 01 0 0 10 0
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