bitrate.m

blind 多径信道中盲信道均衡的恒模算法

function bmap = bitrate(c,w,nu,dopt,ssx,ssn)
% bmap = bitrate(c,w,nu,dopt,ssx,ssn)
%     c = channel
%     w = TEQ
%     nu = cyclic prefix length
%     dopt = starting index of window - 1
%     ssx = signal power
%     ssn = noise power
%
%     Calculates the achievable bit rate for
%     a given ADSL transmission environment
%
%     Modified from code in the DMT-TEQ toolbox,
%     provided by the University of Texas at Austin, ESPL
%
%     Modifications made by Rick Martin, February 2002
%     Last updated 08/08/2002
%     Cornell University Blind Equalization Research Group

margin = 6;         % dB
codingGain = 4.2;   % dB
%inputPower = 23;    % dBm
%awgnpower = -140;
snrgap = 9.8;       % dB (loss)
N = 512;

inputSpec = ssx * ones(1,N/2+1);
noiseSpec = ssn * ones(1,N/2+1);

hw = c;
win = zeros(length(hw),1);
win(dopt+1:dopt+nu+1) = ones(1,nu+1);

% signal path impulse response
hwin = hw.*win;
hwin = hwin - mean(hwin);

% ISI path impulse response
hwout = hw.*(1-win);
hwout = hwout - mean(hwout);

% TEQ frequency response
Fwu = fft(w,N)*sqrt(N);         Fw = Fwu(1:N/2+1).';
Fhwinu = fft(hwin,N)*sqrt(N);   Fhwin = Fhwinu(1:N/2+1).';
Fhwoutu = fft(hwout,N)*sqrt(N); Fhwout = Fhwoutu(1:N/2+1).';

% noise power spectrum
colorNoiseaft = noiseSpec.*abs(Fw).^2;
% ISI power spectrum
isiaft = inputSpec.*abs(Fhwout).^2;
% signal power spectrum
signalaft = inputSpec.*abs(Fhwin).^2;
% subband SNRs after equalization
SNRi = signalaft./( colorNoiseaft + isiaft );

bmap = ba_cal(SNRi,9.8,margin,codingGain,0,100,1);