#include "itcomm.h"

using std::cout;
using std::endl;
using namespace itpp;

int main()
{
    Turbo_Codec turbo;
    ivec gen(2);
    gen(0) = 07; gen(1) = 05;
    int constraint_length = 3;
    int block_length = 400;
    ivec interleaver_sequence = wcdma_turbo_interleaver_sequence(block_length);
    int iterations = 8;
    string metric = "LOGMAX";
    double logmax_scale_factor = 0.7;
    bool adaptive_stop = true;
    turbo.set_parameters(gen, gen, constraint_length, interleaver_sequence, iterations, metric, 
			 logmax_scale_factor, adaptive_stop);
    int num_blocks = 50;

    vec EbN0db = "0.0 0.5 1.0 1.5 2.0";
    double A = 1.0;
    double Ts = 1.0;
    double Ec = A*A*Ts;
    double r = double(block_length) / (3.0 * block_length + 8.0); //8 tailbits are added....
    double Eb = Ec / r;
    vec EbN0 = pow(double(10.0),EbN0db/double(10.0));
    vec N0 = Eb * pow(EbN0,-1.0);
    vec sigma2 = N0/2;
    vec ber(EbN0db.length()); ber.clear();
    vec avg_nrof_iterations(EbN0db.length()); avg_nrof_iterations.clear();
    ivec nrof_used_iterations;
    int i;

    vec rec_systematic, rec_parity, rec_parity1, rec_parity2, extrinsic_input, extrinsic_output, received, symbols;
    bvec input, parity1, parity2, parity_punct, tail1, output1, output2, transmitted, uncoded_bits;
    bvec coded_bits, decoded_bits;

    Normal_RNG noise_src;
    RNG_reset(12345);//Note: RNG_randomize(); will randomize the random sources instead

    BPSK bpsk;
    BERC berc;

    cout << "=============================================" << endl;
    cout << "           Starting Simulation               " << endl;
    cout << " Bit error rate as a function of itterations " << endl;
    cout << "=============================================" << endl;
    cout << "  Block length = " << block_length << endl;
    cout << "  Generator polynomials = " << std::oct << gen << std::dec << endl;
    cout << "  Max number of Iterations = " << iterations << endl;
    cout << "  Adaptive stop = " << adaptive_stop << endl;
    cout << "  Eb/N0 = " << EbN0db << " [dB]" << endl;
    cout << "  Turbo encoder rate 1/3 (plus tail bits)" << endl;
    cout << "=============================================" << endl;

    ivec err(EbN0db.length()), cor(EbN0db.length());
    for (i=0; i<EbN0db.length(); i++) {

	cout << "Now simulating EbN0db = " << EbN0db(i) << endl;

	noise_src.setup(0.0,sigma2(i));
	turbo.set_awgn_channel_parameters(Ec, N0(i));
	input = randb(block_length * num_blocks);

	turbo.encode(input,transmitted);
	bpsk.modulate_bits(transmitted, symbols);
	received = symbols + noise_src(transmitted.length());
	turbo.decode(received, decoded_bits, nrof_used_iterations);

	berc.clear();
	berc.count(input,decoded_bits);
	err(i) = berc.get_errors();
	cor(i) = berc.get_corrects();
	ber(i) = berc.get_errorrate();
	avg_nrof_iterations(i) = double(sum(nrof_used_iterations)) / double(length(nrof_used_iterations));
    }

    cout << "Average numer of iterations used = " << avg_nrof_iterations << endl;
    cout << "err = " << err << endl;
    cout << "cor = " << cor << endl;
    cout << "ber = " << ber << endl;

    return 0;
}