通信算法之一百零四：QPSK完整收发仿真链路

1.发射机物理层基带仿真链路

1.1

% Generates the data to be transmitted

[transmittedBin, ~] = BitGenerator();

2.2

% Modulates the bits into QPSK symbols

modulatedData = QPSKModulator(transmittedBin);

2.3

% Square root Raised Cosine Transmit Filter

%comm.RaisedCosineTransmitFilter('RolloffFactor',               
%    'FilterSpanInSymbols',  'OutputSamplesPerSymbol');

transmittedSignal = TransmitterFilter(modulatedData);

2.信道模型

   % Signal undergoes phase/frequency offset
   rotatedSignal = PhaseFreqOffset(TxSignal);
            
 % Delayed signal
delayedSignal = VariableTimeDelay(rotatedSignal, delay);
            
% Signal passing through AWGN channel
corruptSignal = AWGNChannel(delayedSignal);

3.接收机物理层基带仿真链路

AGCSignal = AGC(bufferSignal);  % AGC control
           

RCRxSignal = RxFilter(AGCSignal);   % Pass the signal through
                                                             % Square-Root Raised Cosine Received Filter
           

[~, freqOffsetEst] = CoarseFreqEstimator(RCRxSignal);  

           % Coarse frequency offset estimation
            % average coarse frequency offset estimate, so that carrier
            % sync is able to lock/converge

coarseCompSignal = CoarseFreqCompensator(RCRxSignal,-freqOffsetEst);                                 % Coarse frequency compensation
 

timingRecSignal = TimingRec(coarseCompSignal); 

% Symbol timing recovery 符号定时，单倍符号率
            
fineCompSignal = FineFreqCompensator(timingRecSignal);  

% Fine frequency compensation  细频偏
            
[symFrame, isFrameValid] = FrameSync(fineCompSignal, );   

% Frame synchronization 帧同步