卷积码编译码程序(6页).doc

上传人:1595****071 文档编号:43089699 上传时间:2022-09-16 格式:DOC 页数:6 大小:128.50KB
返回 下载 相关 举报
卷积码编译码程序(6页).doc_第1页
第1页 / 共6页
卷积码编译码程序(6页).doc_第2页
第2页 / 共6页
点击查看更多>>
资源描述

《卷积码编译码程序(6页).doc》由会员分享,可在线阅读,更多相关《卷积码编译码程序(6页).doc(6页珍藏版)》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。

1、-卷积码编译码程序-第 6 页这是我搜集整理的一个关于卷积编码和Viterbi译码的Matlab程序,现在把它们放在这里,希望对需要的人有些帮助。卷积编码程序:function output, len_tal = cnv_encd(secrettext, encodetext)g = 0 0 1 0 0 1 0 0; 0 0 0 0 0 0 0 1; 1 0 0 0 0 0 0 1; 0 1 0 0 1 1 0 1;k0 = 1;% 读入文本文件并计算文件长度frr = fopen(secrettext, r);msg, len = fread(frr, ubit1);msg = msg;%

2、check to see if extra zero padding is necessaryif rem(length(msg), k0) 0 msg = msg, zeros(size(1:k0-rem(length(msg),k0);endn = length(msg)/k0; % 把输入比特按k0分组,n为所得的组数。% check the size of matrix gif rem(size(g, 2), k0) 0 error(Error, g is not of the right size.);end% determine L and n0L = size(g, 2)/k0;

3、n0 = size(g, 1);% add extra zeros,以保证编码器是从全0开始,并回到全0状态。u = zeros(size(1:(L-1)*k0), msg, zeros(size(1:(L-1)*k0);% generate uu, a matrix whose columns are the contents of conv. encoder at% various clock cycles.u1 = u(L*k0: -1 :1);for i = 1:n+L-2 u1 = u1, u(i+L)*k0:-1:i*k0+1);enduu = reshape(u1, L*k0,

4、n+L-1);% determine the outputoutput = reshape(rem(g*uu, 2), 1, n0*(L+n-1);len_tal = n0*(L + n - 1);% write the output to the encodetextresult = fopen(encodetext, w);for i = 1:n0*(L+n -1) fwrite(result, output(i), bit1);endfclose(result);Viterbi译码程序:function decoder_output, survivor_state, cumulated_

5、metric = viterbi(channel_output, decodetext)ticG= 0 0 1 0 0 1 0 0; 0 0 0 0 0 0 0 1; 1 0 0 0 0 0 0 1; 0 1 0 0 1 1 0 1;k = 1;frr = fopen(channel_output, r);msg, len = fread(frr, ubit1);channel_output = msg;n = size(G,1);% check the sizesif rem(size(G, 2), k) = 0 error(channel_output not of the right s

6、ize);endL = size(G, 2)/k;number_of_states = 2(L-1)*k);% generate state transition matrix, output matrix, and input matrixfor j = 0:number_of_states - 1 for i = 0:2k-1 next_state, memory_contents = nxt_stat(j,i, L, k); input(j+1, next_state + 1) = i; branch_output = rem(memory_contents*G, 2); nextsta

7、te(j+1, i+1) = next_state; output(j+1, i+1) = bin2deci(branch_output); endend% add the extra zero, ensure the length of channel_output is integral% times to n.if rem(len, n)0 channel_output = channel_output, zeros(size(n-rem(len, n):-1:1);endstate_metric = zeros(number_of_states, 2);depth_of_trellis

8、 = length(channel_output)/n;channel_output_matrix = reshape(channel_output, n, depth_of_trellis);survivor_state = zeros(number_of_states, depth_of_trellis + 1);% start decoding of non-tail channel outputsfor i = 1:depth_of_trellis-L+1 flag = zeros(1, number_of_states); if i state_metric(j+1,1). + br

9、anch_metric) | flag(nextstate(j+1, l+1) + 1) = 0) state_metric(nextstate(j+1,l+1)+1, 2) = state_metric(j+1, 1) + branch_metric; suvivor_state(nextstate(j+1,l+1) + 1, i+1) = j; flag(nextstate(j+1, l+1) + 1) = 1; end end end state_metric = state_metric(:, 2:-1:1);end% start decoding of the tail channe

10、l-outputsfor i = depth_of_trellis - L + 2:depth_of_trellis flag = zeros(1, number_of_states); last_stop = number_of_states/(2(i - depth_of_trellis+L-2)*k); for j = 0:last_stop - 1 branch_metric = 0; binary_output = deci2bin(output(j + 1, 1), n); for r = 1:n branch_metric = branch_metric + metric(cha

11、nnel_output_matrix(r, i), binary_output(r); end if(state_metric(nextstate(j+1, l+1) + 1, 2)state_metric(j+1,1). + branch_metric) | flag(nextstate(j+1, 1) + 1) = 0) state_metric(nextstate(j+1,1)+1, 2) = state_metric(j+1, 1) + branch_metric; suvivor_state(nextstate(j+1,1) + 1, i+1) = j; flag(nextstate

12、(j+1, 1) + 1) = 1; end end state_metric = state_metric(:, 2:-1:1);end% generate the decode output from the optimal pathstate_sequence = zeros(1, depth_of_trellis + 1);state_sequence(1, depth_of_trellis) = survivor_state(1, depth_of_trellis+1);for i = 1:depth_of_trellis state_sequence(1, depth_of_tre

13、llis-i+1) = suvivor_state(state_sequence(1, depth_of_trellis+2-i). +1), depth_of_trellis - i+2);enddecoder_output_matrix = zeros(k, depth_of_trellis -L+1);for i = 1:depth_of_trellis - L + 1 dec_output_deci = input(state_sequence(1, i)+1, state_sequence(1, i+1)+1); dec_output_bin = deci2bin(dec_outpu

14、t_deci, k); decoder_output_matrix(:,i) = dec_output_bin(k:-1:1);enddecoder_output = reshape(decoder_output_matrix, 1, k*(depth_of_trellis-L+1);cumulated_metric = state_metric(1, 1);% write the output to the encodetextresult = fopen(decodetext, w);for i = 1:k*(depth_of_trellis-L+1) fwrite(result, dec

15、oder_output(i), bit1);endfclose(result);toc%*%function distance = metric(x,y)if x = y distance = 0;else distance = 1;end%*%function next_state, memory_contents = nxt_stat(current_state, input, L, k)binary_state = deci2bin(current_state, k*(L-1);binary_input = deci2bin(input, k);next_state_binary = b

16、inary_input, binary_state(1:(L-2)*k);next_state = bin2deci(next_state_binary);memory_contents = binary_input, binary_state;%*%function y = bin2deci(x)l = length(x);y = (l-1:-1:0);y = 2.y;y = x*y;%*%function y = deci2bin(x, L)y = zeros(1,L);i = 1;while x = 0 & i= L y(i) = rem(x, 2); x = (x - y(i)/2; i = i + 1;end

展开阅读全文
相关资源
相关搜索

当前位置:首页 > 应用文书 > 合同协议

本站为文档C TO C交易模式,本站只提供存储空间、用户上传的文档直接被用户下载,本站只是中间服务平台,本站所有文档下载所得的收益归上传人(含作者)所有。本站仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私,请立即通知淘文阁网,我们立即给予删除!客服QQ:136780468 微信:18945177775 电话:18904686070

工信部备案号:黑ICP备15003705号© 2020-2023 www.taowenge.com 淘文阁