function runsim(sim_options)

%examine options
fr_length=sim_options.FrmLen;
NumberofPackets=sim_options.NumberofPackets;
option=sim_options.Option;
channel_model=sim_options.ChannelModel;
Tx_antennas=2;
Rx_antennas=sim_options.RxDiv;
corr_value=sim_options.corr_value;

%append zeros to the data to reset this trellis to zero
zf=3; %length of zero appendix. 

%prepare look-up table
[dlt,slt,md] = ltable(option,sim_options);

%md -> number of constellation points. BITS define the number of coded bits
if md==4 %4PSK
    BITS=2;
elseif md==8%8PSK
    BITS=3;
elseif md==16%16QAM
    BITS=4;
end

%examine if MMSE estimation is required. If yes append 20 symbols for
%additional channel noise, since we are using 20 pilot symbols(zeros+10)
if sim_options.Channel_Est==1
    add_est=20;
else
    add_est=0;
end

%SNR variation in dBs
SNR=0:2:20;
h=waitbar(0,'Percentage Completed');
set(h,'Position',[230 50 275.25 56.25]);
set(h,'name','Please wait...');
wb=9.09;
 
%commence loop 
for i=1:length(SNR)
    	source_data = generate_data(fr_length,NumberofPackets,md,zf);
	
        encoded_data = trellis_encoder(source_data,dlt,slt);
	
    	mod_sig = modul(encoded_data,md,sim_options);

	
	    [signal,ch_coefs] = channel(mod_sig,add_est,channel_model,SNR(i),sim_options);


        if sim_options.Channel_Est==1
            [est_coefs,signal]=est(signal,ch_coefs,NumberofPackets,sim_options);
            ch_coefs=est_coefs;
        end    
        if sim_options.Rx_corr==1
        	signal=correlate(signal,corr_value,NumberofPackets);
        end
    
        [data_est,state_est] = detect(signal,dlt,slt,ch_coefs);



% counting the errors
    	[FER_i,SER_i] = count(source_data,data_est);
	
    	SER(i) = SER_i;
        BER(i)=SER(i)/BITS;
        FER(i) = FER_i;
        str_bar=[num2str(wb) '% Completed'];
        waitbar(wb/100,h,str_bar);
        wb=wb+9.09;
    end
close(h);

str1=cd;
str2=sim_options.FileName;
str3=[str1 '\' str2];

if sim_options.Savefile==1
    save(str3);
end

%plot routines. 
figure;
semilogy(SNR,FER,'r-');
hold on
semilogy(SNR,SER,'b-*' );
semilogy(SNR,BER,'g-o');
hold off
xlabel('SNR [dB]')
ylabel('FER/SER/BER')
axis([min(SNR) max(SNR) 1e-6 1e0])
str1='System:';
str2=num2str(2);
str3=num2str(2);
str=[str1 str2 'x' str2];
title(str,'FontWeight','bold','Color','r');
legend('FER','SER','BER');
set(gcf,'NumberTitle','off');
set(gcf,'Name',sim_options.Option);
grid on
[flag]=disptrell(dlt,slt,data_est,state_est);       % display trellis 
if flag
  str1 = num2str(15);
  str2=['Packet is too long!                      '];
  str3=['Only first ',str1,' symbols will be displayed. '];
 msgbox([str2;str3]);
end
figure;
dispdes(dlt,slt);