MIMO无线通信系统VBLAST算法的matlab实现（QR分解）

function output_bit = conv_decoding(input_bit,reset) % convolutional decoding for IEEE802.11a % Input: input_bit is a 1-by-4 matrix represents 4 bits input. % Output: output_bit is a 1-by-2 matrix represents 2 bits output. % Copy right T-Square Design. All rights reserved. % Confidential, do not give this program to anyone outside the T2 IEEE802.11a group. % Current responsible engineer: Antony Lee % When this file is modified, inform Antony Lee, Simon Qiu, Andy Lu. % History % 2002-03-08 Created by Antony Lee. % 2002-04-26 Modified by Simon Qiu. % 2002-07-05 Modified by Simon Qiu: % Reduced one "for" circulation to accelerate calculation rate. global RegisterStateLen; global InputStateLen; global VITERBI_DELAY; global AccumulateDistance; global DelayState; global delayPaths; global curnDelayIndex; global viterbiClockCounter; State_Path_Backward=[ 0 3 13 14; 4 7 9 10; 3 0 14 13; 7 4 10 9; 15 12 2 1; 11 8 6 5; 12 15 1 2; 8 11 5 6; 14 13 3 0; 10 9 7 4; 13 14 0 3; 9 10 4 7; 1 2 12 15; 5 6 8 11; 2 1 15 12; 6 5 11 8; 11 8 6 5; 15 12 2 1; 8 11 5 6; 12 15 1 2; 4 7 9 10; 0 3 13 14; 7 4 10 9; 3 0 14 13; 5 6 8 11; 1 2 12 15; 6 5 11 8; 2 1 15 12; 10 9 7 4; 14 13 3 0; 9 10 4 7; 13 14 0 3; 12 15 1 2; 8 11 5 6; 15 12 2 1; 11 8 6 5; 3 0 14 13; 7 4 10 9; 0 3 13 14; 4 7 9 10; 2 1 15 12; 6 5 11 8; 1 2 12 15; 5 6 8 11; 13 14 0 3; 9 10 4 7; 14 13 3 0; 10 9 7 4; 7 4 10 9; 3 0 14 13; 4 7 9 10; 0 3 13 14; 8 11 5 6; 12 15 1 2; 11 8 6 5; 15 12 2 1; 9 10 4 7; 13 14 0 3; 10 9 7 4; 14 13 3 0; 6 5 11 8; 2 1 15 12; 5 6 8 11; 1 2 12 15]; State_State_Backward = zeros(4,64); State_State_Backward(:) = [1:64,1:64,1:64,1:64]; State_State_Backward = State_State_Backward'; State_Input_Backward = zeros(64,4); State_Input_Backward(17:32,:) = 1; State_Input_Backward(33:48,:) = 2; State_Input_Backward(49:64,:) = 3; StateInitial = [0,8,7,7,7,7,6,6,5,7,6,8,4,6,5,7,3,11,6,6,4,4,7,7,4,6,5,7,5,7,6,8,... 2,8,9,7,5,7,4,6,3,7,4,8,6,6,7,7,3,9,6,4,4,6,7,9,4,8,5,9,5,5,6,6]; if reset == 1 %convolutional decoding initial RegisterStateLen = 64; %6-bit states=2^6=64 InputStateLen = 4; %1-bit Input Path=1^2=2 AccumulateDistance = StateInitial; DelayState = zeros(RegisterStateLen,VITERBI_DELAY+1); delayPaths = zeros(RegisterStateLen,VITERBI_DELAY+1); curnDelayIndex = 1; viterbiClockCounter = 1; output_bit = zeros(1,2); else CurnAccumulateDistance = AccumulateDistance; AccumulateDistance = ones(1,RegisterStateLen) * 127; StateBackward = zeros(RegisterStateLen,1); InputBackward = zeros(RegisterStateLen,1); for curnPath = 1:InputStateLen %InputStateLen = 1--4 tempStateBackward = State_State_Backward(:,curnPath); %look backward to the State tempPathBackward = State_Path_Backward(:,curnPath); %look backward to the Path tempInputBackward = State_Input_Backward(:,curnPath); %look backward to get the input bit %in different rate, the distance computing is different curnDistance = zeros(RegisterStateLen,1); temp = bitget(tempPathBackward,1); %get bit1 if input_bit(1) ~= -1 curnDistance = curnDistance + bitxor(temp,input_bit(1)); %compute the hamming distance end temp = bitget(tempPathBackward,2); %get bit2 if input_bit(2) ~= -1 curnDistance = curnDistance + bitxor(temp,input_bit(2)); %compute the hamming distance end temp = bitget(tempPathBackward,3); %get bit3 if input_bit(3) ~= -1 curnDistance = curnDistance + bitxor(temp,input_bit(3)); %compute the hamming distance end temp = bitget(tempPathBackward,4); %get bit4 if input_bit(4) ~= -1 curnDistance = curnDistance + bitxor(temp,input_bit(4)); %compute the hamming distance end tempAccumulateDistance = CurnAccumulateDistance(tempStateBackward) + curnDistance'; %compute the accumulating hamming distance %add the distance of each state idx = find(tempAccumulateDistance < AccumulateDistance); AccumulateDistance(idx) = tempAccumulateDistance(idx); StateBackward(idx) = tempStateBackward(idx); %select the minimum distance of each state %PathBackward=tempPathBackward; %select the minimum distance of each path InputBackward(idx) = tempInputBackward(idx); %select the minimum distance of each input end DelayState(:,curnDelayIndex) = StateBackward; delayPaths(:,curnDelayIndex) = InputBackward; %save the current input %we define the VITERBI_DELAY, when viterbiClockCounter >= VITERBI_DELAY we output if viterbiClockCounter >= VITERBI_DELAY+1 [AccumulateDistanceMin,tempStateBackward] = min(AccumulateDistance); %we use these function to avoid AccumulateDistance overflow AccumulateDistance = AccumulateDistance - AccumulateDistanceMin; %we trace back to find the correct output traceDelayIndex = curnDelayIndex; for k = 1:VITERBI_DELAY tempStateBackward = DelayState(tempStateBackward,traceDelayIndex); traceDelayIndex = traceDelayIndex - 1; if traceDelayIndex < 1 traceDelayIndex = VITERBI_DELAY + 1; end end output_bit = bitget(delayPaths(tempStateBackward,traceDelayIndex),1:2); else viterbiClockCounter = viterbiClockCounter + 1; output_bit = zeros(1,2); end curnDelayIndex = curnDelayIndex + 1; if curnDelayIndex > VITERBI_DELAY+1 curnDelayIndex = 1; end end