MY_Turbo.rar_turbo_turbo码_turbo码仿真

function [soft_value, extern_value] = max_log_map(input, apri) %% ===========状态转移图开始=========== ... S(i) 0-S(i+1)/b(i)b(i+1) 1-S(i+1)/b(i)b(i+1) ... 1 1/00 5/11 ... 2 5/00 1/11 ... 3 6/01 2/10 ... 4 2/01 6/10 ... 5 3/01 7/10 ... 6 7/01 3/10 ... 7 8/00 4/11 ... 8 4/00 8/11 ... ===========状态转移图结束=========== %% 初始化 len = length(input); infty = 128; state = 2 ^ 3; soft_value = zeros(1, len); next_state = [1 5 6 2 3 7 8 4;... 5 1 2 6 7 3 4 8]; last_state = [1 4 5 8 2 3 6 7;... 2 3 6 7 1 4 5 8]; %初始化软信息 x = input(1, :); y = input(2, :); %初始化alpha、beta和gamma alpha = - infty * ones(state, len); alpha(1, 1) = 0; beta = - infty * ones(state, len + 1); beta(1, len + 1) = 0; gamma = zeros(state, 2, len); gamma([3, 4, 5, 6], 1, :) = repmat(y, 4, 1); gamma([3, 4, 5, 6], 2, :) = repmat(x + apri, 4, 1); gamma([1, 2, 7, 8], 2, :) = repmat(x + y + apri, 4, 1); % gamma(1, 1, :) = 0; % gamma(1, 2, :) = x + y + apri; % gamma(2, 1, :) = 0; % gamma(2, 2, :) = x + y + apri; % gamma(3, 1, :) = y; % gamma(3, 2, :) = x + apri; % gamma(4, 1, :) = y; % gamma(4, 2, :) = x + apri; % gamma(5, 1, :) = y; % gamma(5, 2, :) = x + apri; % gamma(6, 1, :) = y; % gamma(6, 2, :) = x + apri; % gamma(7, 1, :) = 0; % gamma(7, 2, :) = x + y + apri; % gamma(8, 1, :) = 0; % gamma(8, 2, :) = x + y + apri; %% 计算分支度量alpha for k = 2 : len alpha(:, k) = max(squeeze(gamma(last_state(1, :), 1, k - 1)) + alpha(last_state(1, :), k - 1), ... squeeze(gamma(last_state(2, :), 2, k - 1)) + alpha(last_state(2, :), k - 1)); % alpha(1, k) = max(gamma(1, 1, k - 1) + alpha(1, k - 1), gamma(2, 2, k - 1) + alpha(2, k - 1)); % alpha(2, k) = max(gamma(4, 1, k - 1) + alpha(4, k - 1), gamma(3, 2, k - 1) + alpha(3, k - 1)); % alpha(3, k) = max(gamma(5, 1, k - 1) + alpha(5, k - 1), gamma(6, 2, k - 1) + alpha(6, k - 1)); % alpha(4, k) = max(gamma(8, 1, k - 1) + alpha(8, k - 1), gamma(7, 2, k - 1) + alpha(7, k - 1)); % alpha(5, k) = max(gamma(2, 1, k - 1) + alpha(2, k - 1), gamma(1, 2, k - 1) + alpha(1, k - 1)); % alpha(6, k) = max(gamma(3, 1, k - 1) + alpha(3, k - 1), gamma(4, 2, k - 1) + alpha(4, k - 1)); % alpha(7, k) = max(gamma(6, 1, k - 1) + alpha(6, k - 1), gamma(5, 2, k - 1) + alpha(5, k - 1)); % alpha(8, k) = max(gamma(7, 1, k - 1) + alpha(7, k - 1), gamma(8, 2, k - 1) + alpha(8, k - 1)); end %% 计算分支度量beta和LLR for k = len : -1 : 1 beta(:, k) = max(squeeze(gamma(:, 1, k)) + beta(next_state(1, :), k + 1), ... squeeze(gamma(:, 2, k)) + beta(next_state(2, :), k + 1)); soft_value(k) = max(alpha(:, k) + squeeze(gamma(:, 2, k)) + beta(next_state(2, :), k + 1)) - ... max(alpha(:, k) + squeeze(gamma(:, 1, k)) + beta(next_state(1, :), k + 1)) ; % beta(1, k) = max(gamma(1, 1, k) + beta(1, k + 1), gamma(1, 2, k) + beta(5, k + 1)); % beta(2, k) = max(gamma(2, 1, k) + beta(5, k + 1), gamma(2, 2, k) + beta(1, k + 1)); % beta(3, k) = max(gamma(3, 1, k) + beta(6, k + 1), gamma(3, 2, k) + beta(2, k + 1)); % beta(4, k) = max(gamma(4, 1, k) + beta(2, k + 1), gamma(4, 2, k) + beta(6, k + 1)); % beta(5, k) = max(gamma(5, 1, k) + beta(3, k + 1), gamma(5, 2, k) + beta(7, k + 1)); % beta(6, k) = max(gamma(6, 1, k) + beta(7, k + 1), gamma(6, 2, k) + beta(3, k + 1)); % beta(7, k) = max(gamma(7, 1, k) + beta(8, k + 1), gamma(7, 2, k) + beta(4, k + 1)); % beta(8, k) = max(gamma(8, 1, k) + beta(4, k + 1), gamma(8, 2, k) + beta(8, k + 1)); % % store1 = max([alpha(1, k) + gamma(1, 2, k) + beta(5, k + 1), alpha(2, k) + gamma(2, 2, k) + beta(1, k + 1) ... % alpha(3, k) + gamma(3, 2, k) + beta(2, k + 1), alpha(4, k) + gamma(4, 2, k) + beta(6, k + 1) ... % alpha(5, k) + gamma(5, 2, k) + beta(7, k + 1), alpha(6, k) + gamma(6, 2, k) + beta(3, k + 1) ... % alpha(7, k) + gamma(7, 2, k) + beta(4, k + 1), alpha(8, k) + gamma(8, 2, k) + beta(8, k + 1)]); % store0 = max([alpha(1, k) + gamma(1, 1, k) + beta(1, k + 1), alpha(2, k) + gamma(2, 1, k) + beta(5, k + 1) ... % alpha(3, k) + gamma(3, 1, k) + beta(6, k + 1), alpha(4, k) + gamma(4, 1, k) + beta(2, k + 1) ... % alpha(5, k) + gamma(5, 1, k) + beta(3, k + 1), alpha(6, k) + gamma(6, 1, k) + beta(7, k + 1) ... % alpha(7, k) + gamma(7, 1, k) + beta(8, k + 1), alpha(8, k) + gamma(8, 1, k) + beta(4, k + 1)]); % soft_value(k) = store1 - store0; end extern_value = soft_value - x - apri;