通信原理第7章 信道编码和差错控制

1、 发送端发送端接收端接收端信信 源源信道编码信道编码调调 制制信信 道道压缩编码压缩编码解解 调调信信 宿宿保密解码保密解码信道解码信道解码压缩解码压缩解码保密编码保密编码噪噪 声声信 源 编信 源 编码码信 源 解信 源 解码码 接收数据ACKACKNAKACKACKNAKACK1233455t发送数据12334556t有错码组有错码组214365798接收数据有错码组有错码组910 1110 11 12576ACK1NAK5NAK9ACK55769521436798发送数据10 1110 11 12重发码组重发码组选择重发ARQ系统9接收数据有错码组有错码组214365759810 111

2、31412发送数据9958521436710 1113 1412重发码组重发码组NAK9ACK1NAK5ACK5ACK9 信息信息位位监督监督位位晴晴000云云011阴阴101雨雨110k个信息位r个监督位an-1an-2.arar-1an-2.a0t码长 n = k + r(0,0,0)(0,0,1)(1,0,1)(1,0,0)(1,1,0)(0,1,0)(0,1,1)(1,1,1)a2a0a1 0123BA汉明距离ed0码距等于3的两个码组BtA汉明距离012345td0码距等于5的两个码组10-610-510-410-310-210-1编码后Eb/n0 (dB)编码和误码率关系PeCDE

3、AB2PSK 10-610-510-410-310-210-1编码后Eb/n0 (dB)编码和误码率关系PeCDEAB2PSK BsssbRnPTnPnTPnE0000)/1 (10-610-510-410-310-210-1编码后Eb/n0 (dB)编码和误码率关系PeCDEAB2PSK)(/00dBnEnEGcbubdB10-610-510-410-310-210-1编码后Eb/n0 (dB)编码和误码率关系PeCDEAB2PSK1021aaann0021aaann信息位信息位监督位监督位晴晴000云云011阴阴101雨雨110信 息 码 元监督码元11100000001110100110

4、10100001110110001000010011001110111监督码元01101010011S1S2S3错码位置S1S2S3错码位置000无错011a3001a0101a4010a1110a5100a2111a6 信息位监督位信息位监督位a6a5a4a3a2a1a0a6a5a4a3a2a1a00000000100011100010111001100001010110100100011110101100101001101100001010110111010100110011111010001110001111111nrrnkrr1) 12()12( (5)0001001101010101

5、100101110123456aaaaaaa (6)100110101010110010111 1110100H110101010110013456012110110110111aaaaaaa (7) QaaaaPaaaaaaaaaaaT34563456345601211010101111111010001010100011001011100010121aaaaAnn0121bbbbBnnB A = E (模2)0121eeeeEnniiiiiababe当当, 1, 0 T 码组码组编号编号信息位信息位监督位监督位码组码组编号编号信息位信息位监督位监督位A6a5a4a3a2a1a0a6a5a4

6、A3a2a1a01000000051001011200101116101110030101110711001014011100181110010012211)(axaxaxaxTnnnn11010011)(25623456xxxxxxxxxxTnpnpQnm,)()()()(xRxQxNxF）（模)()()(xNxRxF ）（模) 1(133xx）（模) 1(113224xxxxx）（模) 1()()(nixxTxTx）（模) 1()(723535893xxxxxxxxxxTx1)(256xxxxTG34560123456aaaaaaaaaaaA011000110100101100100111

7、1000QGkI I )()()()()(21xgxxgxgxxgxxkkG码组码组编号编号信息位信息位监督位监督位码组码组编号编号信息位信息位监督位监督位A6a5a4a3a2a1a0a6a5a4A3a2a1a01000000051001011200101116101110030101110711001014011100181110010)()()()(2xgxxgxgxxG001011101011101011100)(xG)()()()()()()()()()(452645262456456xgaxaxaxgaxxgaxgxaxgxxgxgxaaaxaaaxTG）（模) 1()()(nixxTxTx1)()(1)(nnkxxTxQxxTx)() 1()(xTxxTxnk )() 1()(xTxxTxnk)()(1xhxxgxkn) 1)(1)(1(13237xxxxxx1) 1)(1(2423xxxxxx1) 1)(1