FSK mod and demod with fading and noise

I'm trying to design FSK modulator and demodulator with noise and flat fading but the graph of snr vs ber with fading in wrong, any idea how to fix it??

clear all;clf;clc;close all;

M = 2; 
k = log2(M);
EbNo = 5;
Fs = 16; 
nsamp = 17; 
freqsep = 8;
n=10000;

msg = randint(n,1,M); 
txsig = fskmod(msg,M,freqsep,nsamp,Fs); 

ab=abs(txsig);
ps=(sum(ab.^2))/n;

for snr=1:30
    pn=10.^(-0.1.*snr).*ps;
    noise= sqrt(pn)*randn(1,n*nsamp); 

G1=randn(1,n); %generating fading coefficients

G2=randn(1,n);
v= sqrt(power(G1,2)+ power(G2,2));
A=v(2);
theta=2*pi*rand;

alph=A*exp(j*theta);
msg_rx  = alph*txsig + noise'; % txsig is 1700x1 and noise is 1x1700, so need transpose
msg_rxx=msg_rx.*(1/A)*conj(alph);
msg_rrx = fskdemod(msg_rxx,M,freqsep,nsamp,Fs);  

[num,BER] = biterr(msg,msg_rrx); % Bit error rate

w(snr)=BER;

end

d=[1:30];
figure
semilogy(d,w)