pnsequence.m

这个是beyong 3G的一个系统仿真程序,它是MC和CDMA的一个结合系统,采用了扩张码的选择.

function pn = pnsequence(genPoly,initState,sqLength)
%PNSEQUENCE Generate Pseudo-Noise(PN) sequence using LFSR
%           (Linear Feedback Shift Registers)
% 
%   PN = PNSEQUENCE(GENPOLY,INITSTATE,SQLENGTH)
% 
%   GENPOLY: Generator Polynomial f(x) = 1 + f1.x + f2.x^2 + ...+ f_r.x^r 
%                             GEN_POLY = [1 f1 f2 ... f_r]
%   INITSATE: Initial sate of the shift registers [x1 x2 .... xr]
%   SQLENGTH: Length of the PN Sequence
%
%   Nguyen Thanh Hieu
%   Multimedia Signal Processing Lab
%   Information and Communication Engineering Department
%   Yeungnam University, Korea

registerState(1,1:length(initState)) = initState;
for j = 1:sqLength
    %1-time cyclicly right-shift
    registerState(j+1,:) = circshift(registerState(j,:),[0 1]);
    %Modulo-2 adder
    registerState(j+1,1) = mod(sum(genPoly(2:end) .* registerState(j,:)),2);
end
pn = registerState(1:sqLength,length(initState))';