57 lines
2.1 KiB
Mathematica
57 lines
2.1 KiB
Mathematica
|
function [y,cpe] = preHECommonPhaseErrorTracking(x,chanEst,fieldName,chanBW)
|
||
|
|
%preHECommonPhaseErrorTracking Estimate and correct common phase error
|
||
|
|
%
|
||
|
|
% [Y,CPE] = preHECommonPhaseErrorTracking(X,CHANEST,FIELDNAME,CHANBW)
|
||
|
|
% returns the phase corrected OFDM symbols and common phase error per
|
||
|
|
% OFDM symbols using the input X, channel estimates, CHANEST, field name,
|
||
|
|
% FIELDNAME and channel bandwidth CHANBW.
|
||
|
|
%
|
||
|
|
% Y are the phase corrected OFDM symbols and is of same size as X. CPE is
|
||
|
|
% of size 1-by-Nsym, contains common phase error for each OFDM symbol.
|
||
|
|
%
|
||
|
|
% X is a complex Nst-by-Nsym-by-Nr array containing the received OFDM
|
||
|
|
% symbols. Nst is the number of subcarriers and Nr is the number of
|
||
|
|
% receive antennas.
|
||
|
|
%
|
||
|
|
% CHANEST is a real or complex array containing the channel estimates for
|
||
|
|
% each carrier. It is of size Nst-by-1-by-Nr.
|
||
|
|
%
|
||
|
|
% FIELDNAME is a character vector or string specifying the field of
|
||
|
|
% interest. The allowed field names are 'L-SIG', 'RL-SIG', 'HE-SIG-A',
|
||
|
|
% and 'HE-SIG-B'.
|
||
|
|
%
|
||
|
|
% CHANBW is a character vector or string. The allowed channel bandwidth
|
||
|
|
% are 'CBW20', 'CBW40', 'CBW80', and 'CBW160'.
|
||
|
|
|
||
|
|
% Copyright 2018-2019 The MathWorks, Inc.
|
||
|
|
|
||
|
|
%#codegen
|
||
|
|
|
||
|
|
numOFDMSym = size(x,2);
|
||
|
|
|
||
|
|
switch fieldName
|
||
|
|
case {'L-SIG','RL-SIG'}
|
||
|
|
z = 0; % Pilot symbol offset
|
||
|
|
ofdmInfo = wlanHEOFDMInfo('L-LTF',chanBW);
|
||
|
|
case 'HE-SIG-A'
|
||
|
|
z = 2;
|
||
|
|
ofdmInfo = wlanHEOFDMInfo('HE-SIG-A',chanBW);
|
||
|
|
case 'HE-SIG-B'
|
||
|
|
z = 2;
|
||
|
|
ofdmInfo = wlanHEOFDMInfo('HE-SIG-B',chanBW);
|
||
|
|
end
|
||
|
|
refPilots = wlan.internal.nonHTPilots(numOFDMSym,z);
|
||
|
|
refPilots = repmat(refPilots,ofdmInfo.NumSubchannels,1);
|
||
|
|
|
||
|
|
% Estimate CPE and phase correct symbols
|
||
|
|
[~,~,fieldPilotInd] = wlan.internal.hePreHEOFDMConfig(chanBW,fieldName);
|
||
|
|
if numel(ofdmInfo.PilotIndices)==size(chanEst,1)
|
||
|
|
% Assume channel estimate is only for pilots
|
||
|
|
chanEstPilots = chanEst;
|
||
|
|
else
|
||
|
|
chanEstPilots = chanEst(ofdmInfo.PilotIndices,:,:);
|
||
|
|
end
|
||
|
|
cpe = wlan.internal.commonPhaseErrorEstimate(x(fieldPilotInd,:,:),chanEstPilots,refPilots);
|
||
|
|
y = wlan.internal.commonPhaseErrorCorrect(x,cpe);
|
||
|
|
|
||
|
|
end
|