New MATLAB files

04 Additions to the Baseline EVM Algorithm/Time Domain Alignment for Single Carrier/F_Save_Results_TimeDomainAlignment.m

+function F_Save_Results_TimeDomainAlignment(EVMrms_pct, tau0, G_OPT)
+
+    % This function saves the outputs from the Alternate TAA case
+    %   EVMrms_pct:   Baseline rms EVM in percent
+    %   tau0:         Optimal time delay before same sampling/calculation
+    %   G_OPT:        Optimal complex gain / normalization factor for symbol samples 
+    %                   (saved as absolute and phase parts)
+    %
+    % It also saves the extra outputs in the same file for users
+    %   rxSigAve:     Received signal average value
+    %   optTolerance: Absolute tolerance determined for iterative delay calculation convergence (ns)
+    %   iterindx:     Number of iterations for optimal delay loop convergence (= 10000 if convergence fails)
+    %   G_0:          Optimal complex gain to be applied before symbol sampling/EVM calculation saved as
+    %   G_0amp:       abs(G_0)
+    %   G_0phase:     angle(G_0) in degrees
+    %   EVMpeak_pct:  Peak EVM (in %)
+    
+    global structGlobal
+
+    G_OPTamp = abs(G_OPT);
+    G_OPTphase = angle(G_OPT)*180/pi; % degrees
+    
+    fname = strcat(structGlobal.filename_results,'.txt');
+    fid = fopen(fullfile(structGlobal.evm_results_folder,fname),'w');
+    fprintf(fid,'\n\n');    
+    fprintf(fid,'%s\n','RESULTS FROM TIME-DOMAIN ALIGNMENT METHOD');
+    
+    Quantity = [{'EVM_rms%', 'Optimal Delay (ns)','G_OPT Amp', 'G_OPT Phase (deg)'}];
+    Value = [EVMrms_pct; tau0; G_OPTamp; G_OPTphase];
+    fprintf(fid,'%s\n','------------------------------------------------');
+    fprintf(fid, '%s \t %s\r\n', 'Quantity', 'Value');
+    fprintf(fid,'%s\n','------------------------------------------------');
+    for n =1:length(Value)
+        fprintf(fid, '%-23s  %1.15g\r\n', Quantity{n}, Value(n));
+    end
+    
+    fprintf(fid,'\n\n');
+    
+    fprintf(fid,'%s\n','Quantity Definition:');
+    fprintf(fid,'%s\n','-----------------------------');
+    fprintf(fid,'%s\n','> EVM_rms% = RMS EVM as a percentage');
+    fprintf(fid,'%s\n','> Optimal Delay (ns) = Optimal time delay to be applied in the phase of XOut before symbol sampling/EVM calculation');
+    fprintf(fid,'%s\n','   where XOut is fftshifted match filtered baseband version of reference signal in frequency domain');
+    fprintf(fid,'%s\n','> G_OPT Amp = Symbol Norm Amp = abs(G_OPT), where G_OPT is optimal complex gain/normalization factor for symbol samples');
+    fprintf(fid,'%s\n','> G_OPT Phase = Symbol Norm Phase = angle(G_OPT) in degrees');
+
+    fprintf(fid,'\n\n');
+    
+    Extra_Quantity = [{'DC Value','Total DC Phase (deg)', 'Delay Tolerance (ns)','EVM_peak%'}];
+    Extra_Value = [structGlobal.rxSigAve; structGlobal.rxTotalAngle; structGlobal.delayTolerance; structGlobal.EVMpeak_pct];
+    fprintf(fid,'%s\n','------------------------------------------------');
+    fprintf(fid, '%s \t\t %s\r\n', 'Extra Quantity', 'Value');
+    fprintf(fid,'%s\n','------------------------------------------------');
+    for n =1:length(Extra_Value)
+        fprintf(fid, '%-23s  %1.15g\r\n', Extra_Quantity{n}, Extra_Value(n));
+    end
+
+    fprintf(fid,'\n\n');
+
+    fprintf(fid,'%s\n','Extra Quantity Definition:');
+    fprintf(fid,'%s\n','--------------------------');
+    fprintf(fid,'%s\n','> DC Value = Received signal average value');
+    fprintf(fid,'%s\n','> Total DC Phase (deg) = Total DC phase as sum of coarse and fine xcorr alignment to be applied to received waveform rxSig before symbol sampling/calculation');
+    fprintf(fid,'%s\n','> Delay Tolerance (ns) = Absolute size of fine time grid used in xcorr');
+    fprintf(fid,'%s\n','> EVM_peak% = Peak EVM as a percentage');    
+    
+    fclose(fid);
+    
+end

04 Additions to the Baseline EVM Algorithm/Time Domain Alignment for Single Carrier/F_TimeDomainAlignment.m

+function F_TimeDomainAlignment(refSigFreq,rxSigFreq,refSig,refConst,params)
+
+    % This function implements the Baseline EVM Algorithm with Time-Domain
+    % Alignment as detailed in Section 9.1.1 of the P1765 document.
+    %
+    % Replace the function call on line 62 in the main program with the following:
+    % F_UserInputs_TimeDomainAlignment()
+    %
+    % Replace lines 99 through 114 in the main program
+    % with the following function call to perform EVM calculation
+    % using time-domain alignment:
+    % F_TimeDomainAlignment(refSigFreq,rxSigFreq,refSig,refConst,params);
+    %
+    % Make sure that the main program uses all these functions in order
+    % to calculate EVM using the time-domain alignment method
+    %   F_UserInputs_TimeDomainAlignment
+    %   F_Basic_Communication_Parameters
+    %   F_Apply_RX_Filter
+    %       F_freqSqrtRaisedCosine
+    %   F_TimeDomainAlignment
+    %       F_calculateOptimal_TimeDomainAlignment
+    %       F_Sample_Normalize_EVM
+    %       F_Plot_Constellation_Diagram
+    %       F_Save_Results_TimeDomainAlignment
+    %
+    % Main program: IEEE_P1765_Baseline_EVM_Algorithm
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    % Inputs:
+    %   refSig:         Time-Domain Waveform from Ideal Constellation    
+    %   refSigFreq:     Frequency-Domain version of refSig
+    % 	rxSigFreq:      Matched Filtered Baseband Reference Waveform in Frequency Domain
+    %   refConst:       Reference Constellation Supplied with this Package
+    %   params:         Structure containing all the basic communication parameters
+    %
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    % Authors:
+    % Christopher P. Silva - Original code Version 04.30.2021
+    % Paritosh Manurkar - Modularization of the code into a main program and subroutines Version 06.28.2021
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    %% Optimal Time Delay and Normalization Algorithm for Waveform Samples (Crosscorrelation)
+    [tau0, rxSig] = F_calculateOptimal_TimeDomainAlignment(refSigFreq,rxSigFreq,refConst,params);
+
+
+    %% Perform Symbol Sampling, Complex Gain Normalization and Calculate EVM
+    [EVMrms_pct,G_OPT] = F_Sample_Normalize_EVM(refSig,rxSig,params);
+
+
+    %% Save Both AlternateTAA and Extra Results in a Single File
+    F_Save_Results_TimeDomainAlignment(EVMrms_pct, tau0, G_OPT);
+
+end
\ No newline at end of file

04 Additions to the Baseline EVM Algorithm/Time Domain Alignment for Single Carrier/F_UserInputs_TimeDomainAlignment.m

+function F_UserInputs_TimeDomainAlignment()
+
+    global structGlobal
+
+%     % Select the folder where these programs reside
+%     uiwait(msgbox({'In order for the program to run correctly,'...
+%         'the parent program folder needs to be selected'...
+%         'as the working directory in the next window.'}));
+%     pause(0.001);
+%     program_folder = uigetdir(pwd,'Select the folder where these programs reside');
+%     cd(program_folder);
+
+    % Select a folder to save the EVM results based on user input');
+    structGlobal.evm_results_folder = uigetdir(pwd,'Select a folder to save EVM calculation results');
+
+    % Read in ASCII Baseband Reference Waveform file
+    disp('__________________________________________________________________');
+    disp('The user’s selection will be based on the P1765 Signal Impairment Sets'); 
+    disp('defined in Section 6.1 and Annex A of IEEE P1765');
+    disp('Read in ASCII Baseband Reference Waveform file');
+    disp('__________________________________________________________________');
+    [filename,path] = uigetfile([pwd,'\P1765 Reference Waveforms\Baseband\Waveform_SIS01_BB.txt'],'Select the signal text file');
+    structGlobal.file = fullfile(path,filename);
+    
+    % Find the starting index of SIS in the filename for default filenaming convention
+    % SIS = Signal Impairment Sets.
+    % The filenames have SIS followed by two digits from 01 through 21
+    SISmn_index_start = strfind(filename,'SIS');
+    SISmn_index_end = SISmn_index_start + 4;
+    % Extract the SISmn from the waveform file
+    structGlobal.SISmn = filename(SISmn_index_start:SISmn_index_end);
+    
+    
+    %% Enter filename to use for saving results or choose to use the default name
+    list = {'DEFAULT filename','CUSTOM filename'};
+    [filename_choice,~] = listdlg('PromptString',...
+        {'Would you like to set a default or custom filename','for EVM results?'},...
+        'SelectionMode','single','ListSize',[250,100],'ListString',list);
+
+    if filename_choice == 1
+        structGlobal.filename_results = strcat('EVM_xcorr_',structGlobal.SISmn);
+    else
+        prompt = {'Enter filename (without extension):'};
+        dlgtitle = 'Custom filename';
+        dims = [1 50];
+        definput = {'evm_results_file'};
+        response = inputdlg(prompt,dlgtitle,dims,definput);
+        structGlobal.filename_results = response{1};
+    end
+
+    
+    %% Enter filename to use for saving constellation diagram or choose to use the default name
+    list = {'DEFAULT filename','CUSTOM filename'};
+    [filename_choice,~] = listdlg('PromptString',...
+        {'Would you like to set a default or custom filename','for constellation diagram?'},...
+        'SelectionMode','single','ListSize',[250,100],'ListString',list);
+
+    if filename_choice == 1
+        structGlobal.filename_constellation = strcat('Constellation_xcorr_',structGlobal.SISmn);
+    else
+        prompt = {'Enter filename (without extension):'};
+        dlgtitle = 'Custom filename';
+        dims = [1 50];
+        definput = {'constellation_diagram_file'};
+        response = inputdlg(prompt,dlgtitle,dims,definput);
+        structGlobal.filename_constellation = response{1};
+    end    
+    
+    
+    disp(['EVM results will be saved in the following folder: ',structGlobal.evm_results_folder]);
+    disp(['Filename for the storing the EVM results: ',structGlobal.filename_results]);
+    disp(['Filename for the saving the constellation diagram: ',structGlobal.filename_constellation]);
+    disp('__________________________________________________________________');
+
+end

04 Additions to the Baseline EVM Algorithm/Time Domain Alignment for Single Carrier/F_calculateOptimal_TimeDomainAlignment.m

+function [tau0, rxSig] = F_calculateOptimal_TimeDomainAlignment(refSigFreq,rxSigFreq,refConst,params)
+
+    % Function to calculate EVM receiver optimal time delay and
+    % complex normalization based on alternate crosscorrelation based TAA.
+    % See Section 9.1.1 Baseline EVM Algorithm with Alternate Time Alignment
+    %
+    % Inputs:
+    %   refSigFreq:     Ideal signal calculated from 64-QAM ideal constellation in frequency domain
+    % 	rxSigFreq:      Match filtered baseband version of measured signal in frequency domain
+    %   refConst:       Reference Constellation Supplied with the package
+    %   params:         Structure containing the basic communication parameters
+    % 	
+    % Outputs:
+    % 	tau0:           Optimal time delay to be applied in phase before same sampling/calculation
+    %   rxSig:          Optimal time delayed/waveform normalized version of measured signal
+    % 
+    % Extra outputs:
+    %	delayTolerance: Absolute size of fine time grid used in xcorr
+    %	rxTotalAngle:   Total DC phase as sum of coarse and fine xcorr alignment to be applied to received waveform rxSig before symbol sampling/calculation
+
+
+    global structGlobal
+    
+    % Normalize Average Power in Received Signal to Match the Reference Signal (Optional)
+    %
+    % 	>  Used for legacy RRC filter case only when applying alternative xcorr method
+    % 	>  Not used for Joost RRC filter case for either time alignment algorithm alternatives
+    %
+    % refSigPower = dot(refSig,refSig)/numSamp;
+    % rxSigPower = dot(rxSig,rxSig)/numSamp;
+    % refrx_pwr_ratio =  refSigPower/rxSigPower;   
+    % rxSig = rxSig*sqrt(refrx_pwr_ratio);
+
+    %
+    % First Round: Determine Sample Delay and Phase Offset for Original Sampling Grid
+    %
+    rxSig = ifft(rxSigFreq);        % Added by Paritosh on 6/15/2021
+    refSig = ifft(refSigFreq);      % Added by Paritosh on 6/15/2021
+    
+    ccorrFreq1 = rxSigFreq .* conj(refSigFreq);
+    ccorr1 = ifft(ccorrFreq1);
+    [m1, ind1] = max(abs(ccorr1));                     
+    ccorrmax1 = ccorr1(ind1);
+    rxDelay1 = ind1 - 1;
+    rxDelayTime1 = rxDelay1/params.fsamp;
+    rxAngle1 = angle(ccorrmax1)*180/pi;
+    rxSig = (circshift(rxSig.',-rxDelay1)).';
+    rxSig = rxSig*exp(1i*pi*-rxAngle1/180);
+    %
+    % Second Round: Determine Vernier Sample Delay and Phase Offset
+    %
+    resfac = 1000;      % Chosen refinement scale of original dt1 sampling grid [to 50 femtosec (fs) spacing in this case]
+    % structGlobal added by Paritosh on 6/15/2021:
+    structGlobal.delayTolerance = 1/(params.fsamp*1000);    % Absolute tolerance on total delay (+/– 50 fs = 0.1% dt1 in this case) 
+    sigSize = length(refSig);   % Also equals length(rxSig)
+    refSig_us = zeros(1,sigSize*resfac);
+    refSig_us(1:params.numSampSym*resfac:sigSize*resfac) = refConst(1:params.numSym);		% Creating ideal fine version of refSig 
+    rxSig_us = interpft(rxSig,resfac*sigSize);
+    refSigFreq_us = fft(refSig_us);
+    rxSigFreq_us = fft(rxSig_us);
+
+    ccorrFreq2 = rxSigFreq_us .* conj(refSigFreq_us);
+    ccorr2 = ifft(ccorrFreq2);
+    [m2, ind2] = max(abs(ccorr2));                     
+    ccorrmax2 = ccorr2(ind2);
+    rxDelay2 = ind2 - 1;
+    rxDelayTime2 = rxDelay2/(params.fsamp*resfac);
+    if rxDelayTime2 > params.dt1                        % Accounting for negative fine delay if needed
+        rxDelayTime2 = rxDelayTime2 - params.tinterval;
+        rxDelay2 = rxDelay2 - params.numSamp*resfac;
+    end
+
+    rxTotalDelayTime = rxDelayTime1 + rxDelayTime2;     % Time delay down to +/– 50 fs
+    rxAngle2 = angle(ccorrmax2)*180/pi;
+    structGlobal.rxTotalAngle = rxAngle1 + rxAngle2;    % Total DC phase offset (degrees); % structGlobal added by Paritosh on 6/15/2021
+    rxSig_us = (circshift(rxSig_us.',-rxDelay2)).';     
+    rxSig_us = rxSig_us*exp(1i*pi*-rxAngle2/180);
+    rxSig = rxSig_us(1:resfac:params.numSamp*resfac);	% Downsampling back to numSamp = sigSize
+    
+    tau0 = rxTotalDelayTime;                            % Added by Paritosh on 6/15/2021
+    
+end