作者jason222333 (Jason22)
看板comm_and_RF
标题Re: [问题] Using 8PSK with viterbi soft-decoding
时间Fri Oct 17 13:48:33 2008
※ ～进入Soft Viterbi之前的确要先取得每个Bit的Soft值
: 然後再利用这些值做Soft Decoding....
: 取得的方法可参考很多最近关於Turbo Decoding的文献...
: 总之就是一个Soft Demodulator.....
: System Desciption r = h*x + n;
: x = trasmit signal; h = fading channel; n = AWGN
: ri = i-th bit in the 8PSK received symbol
: Yi1 = the set of the modulation symbols which i-th bit is equal to 1
: Yi0 = the set of the modulation symbols whick i-th bit is equal to 0
: "he" is the estimation of channel
: Soft Value:
: p(xi=1) = sum p(ri=1 | he*Yi1) & p(xi=0) = sum(ri=0 | he*Yi0)
: we need to normalize two above probabilities by p(xi=1)+p(xi=0)=1
: 大概就像降子，上面是自己凭感觉写的，有错请纠正罗～
请问这个方法是optimal还是sub-optimal?如果我想做optimal来比较BER差距那要如何做呢?
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