Please help this semilogy error message

Please help to fix this problem. I try to plot as semilogy the MRC in Rayleigh fading and BPSK scheme. This needs to display in the same figure the simBer1 in M_Rx=1, 2, 3 with M_Rx=1 in 0:2:12; M_Rx2=0:2:14; M_Rx=3 in 0:2:16

ip = rand(1,N)>0.5; % generating 0,1 with equal probability
s = 2*ip-1; % 0 -> -1; 1 -> 0 >> BPSK modulation 
nRx_max = 3; %number of M branches
M_Rx = [1:nRx_max];

EbN0dB1 = [0:2:12]; EbN0dB2 = [0:2:14]; EbN0dB3 = [0:2:16];

%%%%% EGC %%%%%%%%%%%
for jj = 1:length(M_Rx)
    %%%Common values
    for k = 1:length(EbN0dB1)
        n = 1/sqrt(2)*[randn(M_Rx(jj),N) + j*randn(M_Rx(jj),N)]; % White gaussian noise, 0dB variance
        h = 1/sqrt(2)*[randn(M_Rx(jj),N) + j*randn(M_Rx(jj),N)]; % Rayleigh fading channel
        % Channel and noise Noise addition
        sD = kron(ones(M_Rx(jj),1),s);
        %%% In different values of dBN0dB    
        y1 = h.*sD + 10^(-EbN0dB1(k)/20)*n; %%%%% EbN0dB1 = [0:2:14] %%%%%%%%%%%         

        % equalization with EGC
        y1Hat = y1.*exp(-j*angle(h));     % removing the phase of the channel
        y1Hat = sum(y1Hat,1);             % adding values from all the receive chains  
        % receiver Rx
        ip1Hat = real(y1Hat)>0;
        % numbers the errors
        nErr1(jj,k) = size(find([ip- ip1Hat]),2);    
    end
end
%theoryBer_nRx1 = 0.5.*(1-1*(1+1./EbN0Lin1).^(-0.5)); 
%theoryBer_nRx2 = 0.5*(1 - sqrt(EbN0Lin1.*(EbN0Lin1+2))./(EbN0Lin1+1) );
simBer1 = nErr1/N; % simulated ber
EbN0Lin1 = 10.^(EbN0dB1/10); %EbN0 linear


close all
figure(1)
semilogy(EbN0dB1,simBer1(1,:),'mo-','LineWidth',1);hold on;
semilogy(EbN0dB2,simBer1(2,:),'kp-','LineWidth',1);
semilogy(EbN0dB3,simBer1(3,:),'gs-','LineWidth',1);
grid on
legend('M=1', 'M=2', 'M=3');
xlabel('Eb/No, dB');
ylabel('Bit Error Rate');
title('BER for BPSK modulation with Equal Gain Combining in Rayleigh channel');
axis([0 20 10^-6 2])

Error using semilogy

Vectors must be the same length.

Error in MRC_bpsk.m (line 41)

semilogy(EbN0dB2,simBer1(2,:),'kp-','LineWidth',1);

>>

Answer 1

[VBBV]

N = 100
ip = rand(1,N)>0.5; % generating 0,1 with equal probability
s = 2*ip-1; % 0 -> -1; 1 -> 0 >> BPSK modulation 
nRx_max = 3; %number of M branches
M_Rx = [1:nRx_max];

%EbN0dB1 = [0:2:12]; EbN0dB2 = [0:2:14]; EbN0dB3 = [0:2:16];
EbN0dB = 0:2:16;
%%%%% EGC %%%%%%%%%%%
for jj = 1:length(M_Rx)
    %%%Common values
    for k = 1:length(EbN0dB)
        n = 1/sqrt(2)*[randn(M_Rx(jj),N) + j*randn(M_Rx(jj),N)]; % White gaussian noise, 0dB variance
        h = 1/sqrt(2)*[randn(M_Rx(jj),N) + j*randn(M_Rx(jj),N)]; % Rayleigh fading channel
        % Channel and noise Noise addition
        sD = kron(ones(M_Rx(jj),1),s);
        %%% In different values of dBN0dB    
        y1 = h.*sD + 10^(-EbN0dB(k)/20)*n; %%%%% EbN0dB1 = [0:2:14] %%%%%%%%%%%                 % equalization with EGC
        y1Hat = y1.*exp(-j*angle(h));     % removing the phase of the channel
        y1Hat = sum(y1Hat,1);             % adding values from all the receive chains  
        % receiver Rx
        ip1Hat = real(y1Hat)>0;
        % numbers the errors
        nErr1(jj,k) = size(find([ip- ip1Hat]),2);    
    end
end
%theoryBer_nRx1 = 0.5.*(1-1*(1+1./EbN0Lin1).^(-0.5)); 
%theoryBer_nRx2 = 0.5*(1 - sqrt(EbN0Lin1.*(EbN0Lin1+2))./(EbN0Lin1+1) );
simBer1 = nErr1/N; % simulated ber
EbN0Lin1 = 10.^(EbN0dB/10); %EbN0 linear


close all
figure(1)
semilogy(EbN0dB(1:end-2),simBer1(1,1:end-2),'mo-','LineWidth',1);hold on;
semilogy(EbN0dB(1:end-1),simBer1(2,1:end-1),'kp-','LineWidth',1);hold on;
semilogy(EbN0dB,simBer1(3,:),'gs-','LineWidth',1);
grid on
legend('M=1', 'M=2', 'M=3');
xlabel('Eb/No, dB');
ylabel('Bit Error Rate');
title('BER for BPSK modulation with Equal Gain Combining in Rayleigh channel');
axis([0 20 10^-6 2])

Since you are creating vectors EbN0dB1 ...3, incrementally, with steps of 2, you can create one vector and access those parts individually,

Try the above

[Seahawks]

Hi Vatishsa,

Thanks for your reply. I received error message for you code as below. FYI, i am using 2017b version.

>> MRC_BPSK_1

N =

100

Error using semilogy

Vectors must be the same length.

Error in MRC_BPSK_1 (line 32)

semilogy(EbN0dB(1:end-2),simBer1(1,1:end-2),'mo-','LineWidth',1);hold

on;

[Seahawks]

Hi Vasishta,

My bad. It works well. Thanks

Wooo

[Seahawks]

Vasishta,

Could you please explain if I want EbN0dB1 = [0:2:14]; EbN0dB2 = [0:2:20]; EbN0dB3 = [0:2:24];?

Thanks Seahawkgo

[VBBV]

EbN0dB = 0:2:24; % Again create a common vector with max value (24 in EbN0dB3)
>> EbN0dB =
     0     2     4     6     8    10    12    14    16    18    20    22    24
EbN0dB(1:end-2); % since 20 is 2nd before last element 
>> ans =
     0     2     4     6     8    10    12    14    16    18    20
>> EbN0dB(1:end-5) % since 14 is 5th before last element 
ans =
     0     2     4     6     8    10    12    14