How to solve the RESHAPE error ?

CODE:

%% *Nakagami-m Fading Channel*
clc;clear all;close all;
N = 10^6; % number of bits or symbols
Eb_N0_dB = (0:25); % multiple Eb/N0 values
nTx = 2;
nRx = 2;
m = 2;
for ii = 1:length(Eb_N0_dB)
    
    % Transmitter
    ip = rand(1,N)>0.5; % generating 0,1 with equal probability
    s = 2*ip-1; % BPSK modulation 0 -> -1; 1 -> 0
    
    sMod = kron(s,ones(nRx,1)); %
    sMod = reshape(sMod,[nRx,nTx,N/nTx]); % grouping in [nRx,nTx,N/NTx ] matrix
    
    h = nak_m(m,nRx,nTx);  % Nakagami-m channel
    n = 1/sqrt(2)*(randn(nRx,N/nTx) + 1j*randn(nRx,N/nTx)); % white gaussian noise, 0dB variance
    
    % Channel and noise Noise addition
    y = squeeze(sum(h.*sMod,2)) + 10^(-Eb_N0_dB(ii)/20)*n;
    
    % Receiver
    
    % Forming the Zero Forcing equalization matrix W = inv(H^H*H)*H^H
    % H^H*H is of dimension [nTx x nTx]. In this case [2 x 2]
    % Inverse of a [2x2] matrix [a b; c d] = 1/(ad-bc)[d -b;-c a]
    hCof = zeros(2,2,N/nTx)  ;
    hCof(1,1,:) = sum(h(:,2,:).*conj(h(:,2,:)),1);  % d term
    hCof(2,2,:) = sum(h(:,1,:).*conj(h(:,1,:)),1);  % a term
    hCof(2,1,:) = -sum(h(:,2,:).*conj(h(:,1,:)),1); % c term
    hCof(1,2,:) = -sum(h(:,1,:).*conj(h(:,2,:)),1); % b term
    hDen = ((hCof(1,1,:).*hCof(2,2,:)) - (hCof(1,2,:).*hCof(2,1,:))); % ad-bc term
    hDen = reshape(kron(reshape(hDen,1,N/nTx),ones(2,2)),2,2,N/nTx);  % formatting for division
    hInv = hCof./hDen; % inv(H^H*H)
    
    hMod =  reshape(conj(h),nRx,N); % H^H operation
    
    yMod = kron(y,ones(1,2)); % formatting the received symbol for equalization
    yMod = sum(hMod.*yMod,1); % H^H * y
    yMod =  kron(reshape(yMod,2,N/nTx),ones(1,2)); % formatting
    yHat = sum(reshape(hInv,2,N).*yMod,1); % inv(H^H*H)*H^H*y
    
    % receiver - hard decision decoding
    ipHat = real(yHat)>0;
    
    % counting the errors
    nErr(ii) = size(find([ip- ipHat]),2);
    
end

simBer = nErr/N; % simulated ber
EbN0Lin = 10.^(Eb_N0_dB/10);
theoryBer_nRx1 = 0.5.*(1-1*(1+1./EbN0Lin).^(-0.5));
p = 1/2 - 1/2*(1+1./EbN0Lin).^(-1/2);
theoryBerMRC_nRx2 = p.^2.*(1+2*(1-p));

close all
figure
semilogy(Eb_N0_dB,theoryBer_nRx1,'bp-','LineWidth',2);
hold on
semilogy(Eb_N0_dB,theoryBerMRC_nRx2,'kd-','LineWidth',2);
semilogy(Eb_N0_dB,simBer,'mo-','LineWidth',2);
axis([0 25 10^-5 0.5])
grid on
legend('theory (nTx=1,nRx=1)', 'theory (nTx=1,nRx=2, MRC)', 'sim (nTx=2, nRx=2, ZF)');
xlabel('Average Eb/No,dB');
ylabel('Bit Error Rate');
title('BER for BPSK modulation with 2x2 MIMO and ZF equalizer (Nakagami-m Channel)');

ERROR:

Error using reshape

To RESHAPE the number of elements must not change.
hMod =  reshape(conj(h),nRx,N); % H^H operation

[Stephen23]

"How to solve the RESHAPE error"

Very simple: don't change the number of elements when reshaping.

Please show us the output of this command:

numel(conj(h))

[Supratik Das]

>> numel(conj(h))

ans =

4

[Supratik Das]

function for h = nak_m(m,nRx,nTx)

function H3=nak_m(m,nRx,nTx)

n=zeros(nRx,nTx);

for i=1:2*m

n=n+randn(nRx,nTx).^2;

end

n=n/(2*m);

phi=2*pi*rand(nRx,nTx);

H3=(n.^0.5).*cos(phi)+1j*(n.^0.5).*sin(phi);

[Supratik Das]

could you please help @Stephen

[Stephen23]

hMod =  reshape(conj(h),nRx,N);
%               ^^^^^^^          4 elements
%                       ^^^      = 2
%                           ^    = 1e6

How do you expect to RESHAPE four elements into 2e6 elements?

Four elements can be reshaped into 1x4, 2x2, or 4x1 (or many other with higher dimensions). 2x1e6 is not on that list.

What is the expected output? Do you actually expect to replicate elements, or interpolate, or something else? Is the size of CONJ(H) incorrect: do you expect it to have 2e6 elements?

[Supratik Das]

Yes i expected the size to be 2x1e6, but it came to be 4. How to solve this issue @Stephen. Please help!!!!

[Supratik Das]

Size of conj(h) to be 2x1e6

[Stephen23]

Using the values provided in your original question and the function you provided in this comment:

nTx = 2;
nRx = 2;
m = 2;

h = nak_m(m,nRx,nTx) % please explain how h should have size 2x1e6.

h = 
  -0.4009 + 0.1983i  -0.2413 + 1.1134i
  -1.0830 + 0.1033i   0.4586 - 0.6362i

function H3=nak_m(m,nRx,nTx)
n=zeros(nRx,nTx);
for i=1:2*m
    n=n+randn(nRx,nTx).^2;
end
n=n/(2*m);
phi=2*pi*rand(nRx,nTx);
H3=(n.^0.5).*cos(phi)+1j*(n.^0.5).*sin(phi);
end