% Unicast Verification in GPRS network.
% One cell implementation.
% Without Link Adaptation

% Clear workspace
% clear
% clc

% Maximum time for simulation
t_max = 15*60; % seconds

% Sampling time
t_samp = 0.02; % the time is discrete, with sampling time is 1
% RLC blocks

% Number of Time slots
num_ts = 4;

% Random Carrier to Interference
rctoi = 10 + 5*randn(30,(t_max/t_samp));

% Create Traffic
user_traffic = traff;

for p = 1:3

    % Coding Scheme and user's C/I 
    % 3 different case
    switch p
        case 1
            ctoi = 6*ones(30,(t_max/t_samp));
        case 2
            m = min(rctoi,[],2) * ones(1,(t_max/t_samp));
	        ctoi = rctoi - m + (6*ones(30,(t_max/t_samp)));
    	case 3
	    	m = max(rctoi,[],2) * ones(1,(t_max/t_samp));
	        ctoi = rctoi - m + 6*ones(30,(t_max/t_samp));
    end

    %Fixed Coding Scheme
    cs = ones(30,(t_max/t_samp)); 

    % Initialization
    buffhist = zeros(1,30);
    overall_th = zeros(1,30);
    packet_loss = zeros(1,30);
    bits_loss = zeros(1,30);

    % to make a graph, user 2-50

    for N_user = 2:30
    
        N_user
    
        % Create Buffer
        buffer = zeros(1,N_user);

        %user throughput
        average_th = zeros(1,N_user);
        data = zeros(1,N_user);

        % User's delay 
        delay = zeros(1,N_user);

        % Loss channel
        p_loss_chan = zeros(1,N_user); %packet
        b_loss_chan = zeros(1,N_user); %bits

        % Let it start!!!
        t_old = 0;
        t_new = t_old + t_samp;

        user = 1 ;
        
        while (t_new<t_max-0.0001)
    
            % Update buffer 
            buffer = buffer + sum(user_traffic(floor(t_old/t_samp+1):floor((t_new/t_samp)))); % fill buffer with packet
    
            % transmitting data
            switch (cs(user,floor((t_old/t_samp)+1)))
                case 1
                    bitrate = num_ts*9050; %coding scheme 1
                case 2
                    bitrate = num_ts*13400; %coding scheme 2
                case 3
                    bitrate = num_ts*15600; %coding scheme 3
                case 4
                    bitrate = num_ts*21400; %coding scheme 4
            end

            transmitted = bitrate * 0.0046 * 4; %4 RLC blocks
    
            if (buffer(user) < transmitted)
                transmitted = buffer(user);
            end
    
            % emptying buffer
            buffer(user) = buffer(user)-transmitted; 
    
            %calculating throughput
            a = per(cs(user,floor((t_old/t_samp)+1)),ctoi(user,floor((t_old/t_samp)+1)));
            aa = a*ones(1,num_ts);
            b = rand(1,num_ts) ;
            success = find (b>=aa);
            data(user) = data(user) + ((transmitted/num_ts)*length(success));
            fail = find (b<aa);
            p_loss_chan(user) = p_loss_chan(user) + length(fail) ;
            b_loss_chan(user) = b_loss_chan(user) + ((transmitted/num_ts)*length(fail));
        
            % Next time, next user
            user = mod(user,N_user)+1;
            t_old = t_new;
            t_new = t_new + t_samp; % update time
        end

        % Overall throughput
        average_th = data/t_max;
        overall_th(N_user) = sum(average_th)/N_user;
        %average packet loss
        all_packet = (t_max/t_samp)*4;
        packet_loss(N_user) = sum(p_loss_chan)/(all_packet);
        %average bits loss
        bits_loss(N_user) = sum(b_loss_chan)/(N_user*t_max);
        %buffer history
        buffhist(N_user) = sum(buffer)/N_user;
    
    end

    x = 2:1:30;
    figure(1)
    switch p
    case 1
        th_uni_fixed = overall_th;
        pl_uni_fixed = packet_loss;
        bf_uni_fixed = buffhist;
        subplot(3,1,1);plot(x,overall_th(2:30),'*');hold on;grid on;title('Unicast Throughput');
        subplot(3,1,2);plot(x,packet_loss(2:30),'*');hold on;grid on;title('Unicast Block Error Rate');
        subplot(3,1,3);plot(x,buffhist(2:30),'*');hold on;grid on;title('Unicast Bits Loss in Buffer');
    case 2
        th_uni_varplus = overall_th;
        pl_uni_varplus = packet_loss;
        bf_uni_varplus = buffhist;
        subplot(3,1,1);plot(x,overall_th(2:30),'+');hold on;grid on;title('Unicast Throughput');
        subplot(3,1,2);plot(x,packet_loss(2:30),'+');hold on;grid on;title('Unicast Block Error Rate');
        subplot(3,1,3);plot(x,buffhist(2:30),'+');hold on;grid on;title('Unicast Bits Loss in Buffer');
    case 3
        th_uni_varmin = overall_th;
        pl_uni_varmin = packet_loss;
        bf_uni_varmin = buffhist;
        subplot(3,1,1);plot(x,overall_th(2:30),'-');hold on;grid on;title('Unicast Throughput');
        subplot(3,1,2);plot(x,packet_loss(2:30),'-');hold on;grid on;title('Unicast Block Error Rate');
        subplot(3,1,3);plot(x,buffhist(2:30),'-');hold on;grid on;title('Unicast Bits Loss in Buffer');
    end
    
end

clear overall_th buffhist packet_loss bits_loss ctoi average_th t_old t_new cs data N_user a b p_loss_chan b_loss_chan success fail transmitted user all_packet bitrate delay index user_traffic CIR_multi CIR_uni CIR buffer traff aa 
save ver_uni