How to modify modem.qammod for the latest MATLAB version?

clc ;
clear all ;
close all ;
m =512; % Total number of OFDM symbols
N =1024; % Length of each OFDM symbol
M =4; % Size of the Constellation ( M can be 4 , 8 , 16 ,32 , 64 , 128 , 256)

pilotFrequency =8 ; % Pilot Symbol insertion frequency
E =2; % Energy of each Pilot Symbol
Ncp =256 ; % Length of the Cyclic Prefix
Tx = modem.qammod ('M',M ) ; % Choosing the modulation format as M - ary Quadrature Amplitude Modulation (M- QAM )

'modem.qammod' has been removed. With appropriate code changes, use 'qammod' instead.

Caused by:
Unable to resolve the name 'modem.qammod'.

Rx = modem.qamdemod ('M',M) ; % Fixing up the demodulation format at the receiving end as M - ary QAM

% ACO - OFDM Transmitter
Data = randi ([0 M-1] ,m , N ); % Generation of Random bits Matrix of size m by N
for k1 =1: m
for m1 =1: N
if mod ( m1 ,2) ==0 % Performing Modulo operation to extract the even subcarriers
Data ( k1 , m1 ) =0; % Setting the Even Subcarriers to Zero
end
end
end

DataMod = modulate ( Tx , Data ) ; % Performing Data Modulation
DataMod_serialtoparallel = DataMod .'; % Performing Serial to Parallel Conversion
PLoc = 1: pilotFrequency :N ; % Fixing the location of Pilot carrires
DLoc = setxor (1: N , PLoc ) ; % Fixing the location of Data subcarriers
DataMod_serialtoparallel ( PLoc ,:) = E*DataMod_serialtoparallel ( PLoc ,:) ; % Inserting Pilot carriers

datamat = DataMod_serialtoparallel ; % Assigning the total data including the pilots to a variable called datamat
% Computation of Hermitian Symmetry Criteria
datamat (1 ,:) =0; % Assigning the First subcarrier to Zero
datamat (513 ,:) =0; % Assigning the Middle Subcarrier to Zero
datamat (514:1024 ,:) = flipud ( conj ( datamat (2:512 ,:) )) ; % Illustrating that only half of the subcarriers are exploited for data transmission as the remaining half are flipped complex conjugate versions of the previous ones .

d_ifft = ifft (( datamat ) ) ; % Computation of IFFT operation

% Ensuring that only the positive portion of the signal is transmitted
for k2 =1: N
for m2 =1: m
if( d_ifft ( k2 , m2 ) <0)
d_ifft ( k2 , m2 ) =0;
end
end
end

d_ifft_paralleltoserial = d_ifft .'; % Parallel to Serial Conversion
CP_part = d_ifft_paralleltoserial (: ,end - Ncp +1: end) ; %Addition of Cyclic Prefix
ACOOFDM_CP =[ CP_part d_ifft_paralleltoserial ]; %Transmissin of ACO - OFDM signal

% VLC Channel Modeling
theta = 70; %LED semi - angle
ml = - log10 (2) / log10 ( cos ( theta ) ) ; % Computation of Lambertian Mode Number
APD =0.01; % Area of the photodiode
lx =5; ly =5; lz =3; % Size of the Dimensions of the Indoor Room Environment
h =2.15;
[ XT , YT ]= meshgrid ([ - lx /4 lx /4] ,[ - ly /4 ly /4]) ;
Nx = lx *5; Ny = ly *5;
x = linspace ( - lx /2 , lx /2 , Nx );
y = linspace ( - ly /2 , ly /2 , Ny );
[ XR , YR ]= meshgrid (x , y );

D1 = sqrt (( XR - XT (1 ,1) ) .^2+( YR - YT (1 ,1) ) .^2+ h ^2) ;
D2 = sqrt (( XR - XT (2 ,2) ) .^2+( YR - YT (2 ,2) ) .^2+ h ^2) ;
cosphi_A1 = h ./ D1 ;
receiver_angle = acosd ( cosphi_A1 ) ;

H_A1 =3600*(( ml +1) * APD .* cosphi_A1 .^( ml +1) ./(2* pi .* D1.^2) +( ml +1) * APD .* cosphi_A1 .^( ml +1) ./(2* pi .^2* D1.^2* D2 .^2) ) ; % Computation of VLC channel Impulse Response taking into consideration Non Line of Sight ( NLOS ) Environment
H_A2 = H_A1 ./ norm ( H_A1 );

d_channell = filter ( H_A2 (1 ,1:2) ,1 , ACOOFDM_CP .') .'; %Illustration of channel effect on the transmitted ACO - OFDM signal

count =0;
snr_vector =0:1:30; % size of signal to noise ratio (SNR ) vector

for snr = snr_vector
    SNR = snr + 10* log10 ( log2 (M ) ) ;
    count = count +1 ;
    ACOOFDM_with_chann = awgn(d_channell , SNR ,'measured') ; % Addition of AWGN
    % Receiver of ACO - OFDM
    ACOOFDM_removal_CP = ACOOFDM_with_chann (: , Ncp+1: N + Ncp );
    % Removal of Cyclic Prefix
    ACOOFDM_serialtoparallel = ACOOFDM_removal_CP .'; %Serial to Parallel Conversion
    ACOOFDM_parallel_fft = fft ( ACOOFDM_serialtoparallel) ; 
    % Computation of FFT operation 
    % Channel Estimation
    TransmittedPilots = DataMod_serialtoparallel ( PLoc,:) ; % Extracting the transmitted pilots
    ReceivedPilots = ACOOFDM_parallel_fft ( PLoc ,:) ; 
    %Extracting the received pilot tones effected by channel
    for r =1:m
        H_MMSE(: , r ) = MMSE(ReceivedPilots(: , r ) ,TransmittedPilots(: , r ), N, pilotFrequency, H_A2(1 ,1:2), SNR);% Minimum Mean SquareError ( MMSE ) Channel Estimation
    end
    
    HData_MMSE_parallel1 = H_MMSE.';
    ACOOFDM_SERIAL_MMSE = demodulate(Rx ,(ACOOFDM_parallel_fft.')./( HData_MMSE_parallel1) ) ;
    
    % Recovery of Pilots from the Original Transmitted signal and Received Signal
    Data_no_pilots = Data (: , DLoc ) ;
    Recovered_Pilot_MMSE = ACOOFDM_SERIAL_MMSE (: , DLoc ) ;
    % Computation of Bit Error Rate
    [~ , recoveredMMSE( count ) ]= biterr ( Data_no_pilots (: ,2:255) , Recovered_Pilot_MMSE (: ,2:255) ) ;
end
% Plotting the BER curves
semilogy ( snr_vector , recoveredMMSE ,'gs -','LineWidth',2) ;
axis ([0 30 10^ -4 1]) ;
grid on ;

function H_MMSE = MMSE(RxP,TxP,N,pilotFrequency,h_CIR,SNR)
% I modified the MMSE_CE function provided in :MIMO-OFDM Wireless 
% Communications with MATLAB¢ç   Yong Soo Cho, Jaekwon Kim, 
% Won Young Yang and Chung G. Kang
%2010 John Wiley & Sons (Asia) Pte Ltd
% The modification made the function more suitable with my OFDM Matlab code
noiseVar = 10^(SNR*0.1);
Np=N/pilotFrequency; % Number of Pilots
H_LS = RxP./TxP;  % LS estimate
k=0:length(h_CIR)-1; 
hh = h_CIR*h_CIR'; 
% tmp = h_CIR.*conj(h_CIR).*k;
r = sum(h_CIR.*conj(h_CIR).*k)/hh;  
r2 = (h_CIR.*conj(h_CIR).*k)*k.'/hh;
t_rms = sqrt(r2-r^2);     % rms delay
D = 1j*2*pi*t_rms/N; % Denomerator of Eq. (6.16) page 192
K1 = repmat([0:N-1].',1,Np);
K2 = repmat([0:Np-1],N,1);
rf = 1./(1+D*(K1-K2*pilotFrequency));
K3 = repmat([0:Np-1].',1,Np);
K4 = repmat([0:Np-1],Np,1);
rf2 = 1./(1+D*pilotFrequency*(K3-K4));
Rhp = rf;
Rpp = rf2 + eye(length(H_LS),length(H_LS))/noiseVar;
H_MMSE = transpose(Rhp*inv(Rpp)*H_LS);  % MMSE channel estimate

end

[Marwah]

Hi

I am a researcher in this area, mostly share the same questions with you. Do you mind if we can work on these together?

Please, contact me on my email if it is ok

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