Communication algorithm Xi.: QPSK/DQPSK/OQPSK/BPSK/DBPSK/16QAM modulation and demodulation simulation link

I. QPSK

orthogonal Phase shift keying (quadrature Phase Shift keying) is referred to as "QPSK" and is a digital modulation method. It is divided into two kinds: absolute phase shift and relative phase shift. Because of the phase ambiguity problem in the absolute phase shift, the relative shift phase is used to dqpsk the method. It has been widely used in wireless communication and has become a very important modulation and demodulation method in modern communication.

Two. QPSK:

Ebno=9.6db

Ecno=12.6db

Four. QPSK emulation link

%****************************************************************
% Content Overview: QPSK modulation and QPSK demodulation simulation link
% emulation Link:
% Creator: Lee gang
% created: October 20, 2014
% References:
% copyright notice: Not to be reproduced at will and not freely disseminated.
%****************************************************************
Clc
Close all
Clear All
% System Parameters---------------------------------------
Sourcebitlen = 1000;
Snr = (12:0.1:15);% signal-to-noise ratio
Berebno = Zeros (1,length (SNR));
For Nen=1:length (SNR)
Err_counter = 0;
For nframe=1:2000
% input source bit sequence----------------------------------
Sourcebit = Randint (1,sourcebitlen);
%QPSK modulation---------------------------------------
out = Lgqpskmod (sourcebit);
% Gaussian white noise channel---------------------------------
Outch = CHANNELAWGN (Out,snr (NEN));
%QPSK demodulation-------------------------------------
[Berdateout Soft] = Lgqpskdemod (III,QQQ);
%ber------------------------------------------
Berdatain = (sourcebit. ');
[Errnum,errrate] = Biterr (berdatain,berdateout);
DISP ([' bit error rate = ', Num2str (errrate), ', error bit number = ', Num2str (Errnum)]);
Err_counter = Err_counter + errnum;
Ber = Err_counter/nframe/sourcebitlen;
End
Berebno (NEN) = Ber;
fprintf (' Ecno:%1.3fdb, ber:%8.6e,\n ', SNR (NEN), BER);
End
Grid on;
Semilogy (snr,berebno, ' b-v ');
Xlabel (' ec/no[db] ');
Ylabel (' Bit Error rate ');
Title (' QPSK modulation, demodulation performance simulation ber curve ');
%---------------------------------------------

Five. Simulation graphics

Post-modulation constellation diagram:

Before Demodulation:

Six. BPSK

(1)

Ebno = 9.6dB

(2) Simulation link slightly

(3) Error rate curve

Seven.

Dbpsk ber Curve

Dqpsk ber Curve

Oqpsk ber Curve

16QAM ber Curve

"Detailed information, and the corresponding MATLAB code, consulting QQ: 1279682290 "

Communication algorithm Xi.: QPSK/DQPSK/OQPSK/BPSK/DBPSK/16QAM modulation and demodulation simulation link