vec mix::process(bvec ce, mat x)
{
vec y;
int N;
bvec one = ("1");
#if (DEBUG_LEVEL==3)
cout << "***** mix::process *****" << endl;
cout << "ce=" << ce << endl;
cout << "x=" << x << endl;
sleep(1000);
#endif
N=ce.length();
if (x.rows()!=N) {
throw sci_exception("mix::process - ce.size <> x.rows()", x.rows() );
}
if (x.cols()!=2) {
throw sci_exception("mix::process - x=[x1,x1] - x.cols()!=2", x.cols() );
}
y.set_length(N);
for (int i=0; i<N; i++) {
if ( bool(ce[i])) {
y0 = G.process(one, to_vec(x(i,0)*x(i,1)))(0);
}
y[i]=y0;
}
#if (DEBUG_LEVEL==3)
cout << "y=" << y << endl;
cout << "+++++ mix::process +++++" << endl;
sleep(1000);
#endif
return (y);
}
cvec fir_x::process(bvec ce, cvec x)
{
cvec y;
int N;
#if (DEBUG_LEVEL==3)
cout << "***** fir_x::proc *****" << endl;
cout << "ce=" << ce << endl;
cout << "x=" << x << endl;
sleep(1000);
#endif
N=ce.length();
if (x.length()!=N) {
throw sci_exception("fir_x::process - ce.size <> x.size", x.length() );
}
y.set_size(N);
for (int i=0; i<N; i++) {
if (bool(ce[i])) y0=update(x[i]);
y[i]=y0;
}
#if (DEBUG_LEVEL==3)
cout << "y=" << y << endl;
cout << "+++++ fir_x::proc +++++" << endl;
sleep(1000);
#endif
return (y);
}
bvec Extended_Golay::decode(const bvec &coded_bits)
{
int no_bits = coded_bits.length();
int no_blocks = (int)floor((double)no_bits/24);
bvec output(12*no_blocks);
int i;
int j;
bvec S(12),BS(12),r(12),temp(12),e(24),c(24);
bmat eyetemp = eye_b(12);
for (i=0; i<no_blocks; i++) {
r = coded_bits.mid(i*24,24);
// Step 1. Compute S=G*r.
S = G*r;
// Step 2. w(S)<=3. e=(S,0). Goto 8.
if( weight(S) <= 3 ) {
e = concat(S, zeros_b(12)); goto Step8;
}
// Step 3. w(S+Ii)<=2. e=(S+Ii,yi). Goto 8.
for (j=0; j<12; j++) {
temp = S + B.get_col(j);
if ( weight(temp) <=2 ) {
e = concat(temp, eyetemp.get_row(j)); goto Step8;
}
}
// STEP 4. Compute B*S
BS = B*S;
// Step 5. w(B*S)<=3. e=(0,BS). Goto8.
if ( weight(BS) <=3 ) {
e = concat(zeros_b(12), BS); goto Step8;
}
// Step 6. w(BS+Ri)<=2. e=(xi,BS+Ri). Goto 8.
for (j=0; j<12; j++) {
temp = BS + B.get_row(j);
if ( weight(temp) <=2 ) {
e = concat(eyetemp.get_row(j), temp); goto Step8;
}
}
// Step 7. Uncorrectable erreor pattern. Choose the first 12 bits.
e = zeros_b(24); goto Step8;
Step8: // Step 8. c=r+e. STOP
c = r + e;
output.replace_mid(i*12, c.left(12));
}
return output;
}
void BERC::estimate_delay(const bvec &in1, const bvec &in2, int mindelay,
int maxdelay)
{
int num, start1, start2;
int min_input_length = std::min(in1.length(), in2.length());
int bestdelay = mindelay;
double correlation;
double bestcorr = 0;
for (int i = mindelay; i < maxdelay; i++) {
num = min_input_length - std::abs(i) - ignorefirst - ignorelast;
start1 = (i < 0) ? -i : 0;
start2 = (i > 0) ? i : 0;
correlation = fabs(sum(to_vec(elem_mult(in1.mid(start1, num),
in2.mid(start2, num)))));
if (correlation > bestcorr) {
bestdelay = i;
bestcorr = correlation;
}
}
delay = bestdelay;
}
bvec Extended_Golay::encode(const bvec &uncoded_bits)
{
int no_bits = uncoded_bits.length();
int no_blocks = (int)floor((double)no_bits/12);
bvec output(24*no_blocks);
int i;
for (i=0; i<no_blocks; i++)
output.replace_mid(24*i, uncoded_bits.mid(i*12,12)*G);
return output;
}
void Hamming_Code::encode(const bvec &uncoded_bits, bvec &coded_bits)
{
int length = uncoded_bits.length();
int Itterations = floor_i(static_cast<double>(length) / k);
bmat Gt = G.T();
int i;
coded_bits.set_size(Itterations * n, false);
//Code all codewords
for (i = 0; i < Itterations; i++)
coded_bits.replace_mid(n*i, Gt * uncoded_bits.mid(i*k, k));
}
void BLERC::count(const bvec &in1, const bvec &in2)
{
it_assert(setup_done == true,
"BLERC::count(): Block size has to be setup before counting errors.");
int min_input_length = std::min(in1.length(), in2.length());
it_assert(blocksize <= min_input_length,
"BLERC::count(): Block size must not be longer than input vectors.");
for (int i = 0; i < (min_input_length / blocksize); i++) {
CORR = true;
for (int j = 0; j < blocksize; j++) {
if (in1(i * blocksize + j) != in2(i * blocksize + j)) {
CORR = false;
break;
}
}
if (CORR) {
corrects++;
}
else {
errors++;
}
}
}
double BERC::count_errors(const bvec &in1, const bvec &in2, int indelay,
int inignorefirst, int inignorelast)
{
int countlength = std::min(in1.length(), in2.length()) - std::abs(indelay)
- inignorefirst - inignorelast;
int local_errors = 0;
if (indelay >= 0) {
for (int i = 0; i < countlength; i++) {
if (in1(i + inignorefirst) != in2(i + inignorefirst + indelay)) {
local_errors++;
}
}
}
else {
for (int i = 0; i < countlength; i++) {
if (in1(i + inignorefirst - indelay) != in2(i + inignorefirst)) {
local_errors++;
}
}
}
return local_errors;
}
char sigma2::bvec2char(bvec &bv, int pos)
{
char ret = 0;
int a[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
if(pos > bv.length() - 8)
{
cout << "Can sua loi nay";
return 0;
}
for(int i = pos; i < pos + 8; i++)
{
if(bv[i] == 1)
ret = ret | a[7 - i + pos];
}
return ret;
}
vec spreading(bvec data,vec code)
{
vec result;
vec code_neg=code*-1;
for(int i=0; i<data.length();i++)
{
if(data[i]==1)
{
result=concat(result,code);
}
else
{
result=concat(result,code_neg);
}
}
return result;
}
void Reed_Solomon::encode(const bvec &uncoded_bits, bvec &coded_bits)
{
int i, j, iterations = floor_i(static_cast<double>(uncoded_bits.length())
/ (k * m));
GFX mx(q, k), cx(q, n);
GFX r(n + 1, n - k);
GFX uncoded_shifted(n + 1, n);
GF mpow;
bvec mbit(k * m), cbit(m);
coded_bits.set_size(iterations * n * m, false);
if (systematic)
for (i = 0; i < n - k; i++)
uncoded_shifted[i] = GF(n + 1, -1);
for (i = 0; i < iterations; i++) {
//Fix the message polynom m(x).
for (j = 0; j < k; j++) {
mpow.set(q, uncoded_bits.mid((i * m * k) + (j * m), m));
mx[j] = mpow;
if (systematic) {
cx[j] = mx[j];
uncoded_shifted[j + n - k] = mx[j];
}
}
//Fix the outputbits cbit.
if (systematic) {
r = modgfx(uncoded_shifted, g);
for (j = k; j < n; j++) {
cx[j] = r[j - k];
}
}
else {
cx = g * mx;
}
for (j = 0; j < n; j++) {
cbit = cx[j].get_vectorspace();
coded_bits.replace_mid((i * n * m) + (j * m), cbit);
}
}
}
void cofdm_map::set_pilots(bvec x)
{
int K = x.length();
complex<double> p1 ( PA , 0.0);
complex<double> p0 (-PA , 0.0);
int L = zero_carriers.length();
complex<double> c0 (0.0 , 0.0);
int i;
if( K == pilots_carriers.length() ) {
for (i=0; i<K; i++) {
y0(pilots_carriers(i))=x(i)?p1:p0;
}
for (i=0; i<L; i++) {
y0(zero_carriers(i))=c0;
}
}
else {
throw sci_exception("cofdm_map::set_pilots - x.size() <> pilots_carriers.size()=", pilots_carriers.length());
}
}
cvec qam_mod::process(bvec ce, ivec x)
{
cvec y;
int N;
ivec iv;
cvec cv;
#if (DEBUG_LEVEL==3)
cout << "***** qam_mod::process *****" << endl;
cout << "ce=" << ce << endl;
cout << "x=" << x << endl;
sleep(1000);
#endif
iv.set_length(1);
cv.set_length(1);
N=ce.length();
y.set_length(N);
if (x.length()!=N) {
throw sci_exception("qam_mod::process - ce.size <> x.size", x.length() );
}
for (int i=0; i<N; i++) {
if ( bool(ce[i])) {
iv[0] = x[i];
cv = modulate(iv);
y0 = scale * cv[0];
}
y[i]=y0;
}
#if (DEBUG_LEVEL==3)
cout << "y=" << y << endl;
cout << "+++++ qam_mod::process +++++" << endl;
sleep(1000);
#endif
return (y);
}
bmat int2bin::process(bvec ce, ivec x)
{
bmat y;
int N;
#if (DEBUG_LEVEL==3)
cout << "***** int2bin::process *****" << endl;
cout << "ce=" << ce << endl;
cout << "x=" << x << endl;
sleep(1000);
#endif
N=ce.length();
if (x.length()!=N) {
throw sci_exception("int2bin::process - ce.size <> x.rows()", x.length() );
}
y.set_size(N,symbol_size);
for (int i=0; i<N; i++) {
if ( bool(ce[i])) {
y0 = dec2bin(symbol_size, x[i]);
if (! msb_first) {
y0 = reverse(y0);
}
}
y.set_row(i,y0);
}
#if (DEBUG_LEVEL==3)
cout << "y=" << y << endl;
cout << "+++++ int2bin::process +++++" << endl;
sleep(1000);
#endif
return (y);
}
bool any(const bvec &testvec)
{
for (int i = 0; i < testvec.length(); i++)
if (testvec(i)) return true;
return false;
}
bool Reed_Solomon::decode(const bvec &coded_bits, const ivec &erasure_positions, bvec &decoded_message, bvec &cw_isvalid)
{
bool decoderfailure, no_dec_failure;
int j, i, kk, l, L, foundzeros, iterations = floor_i(static_cast<double>(coded_bits.length()) / (n * m));
bvec mbit(m * k);
decoded_message.set_size(iterations * k * m, false);
cw_isvalid.set_length(iterations);
GFX rx(q, n - 1), cx(q, n - 1), mx(q, k - 1), ex(q, n - 1), S(q, 2 * t), Xi(q, 2 * t), Gamma(q), Lambda(q),
Psiprime(q), OldLambda(q), T(q), Omega(q);
GFX dummy(q), One(q, (char*)"0"), Omegatemp(q);
GF delta(q), tempsum(q), rtemp(q), temp(q), Xk(q), Xkinv(q);
ivec errorpos;
if ( erasure_positions.length() ) {
it_assert(max(erasure_positions) < iterations*n, "Reed_Solomon::decode: erasure position is invalid.");
}
no_dec_failure = true;
for (i = 0; i < iterations; i++) {
decoderfailure = false;
//Fix the received polynomial r(x)
for (j = 0; j < n; j++) {
rtemp.set(q, coded_bits.mid(i * n * m + j * m, m));
rx[j] = rtemp;
}
// Fix the Erasure polynomial Gamma(x)
// and replace erased coordinates with zeros
rtemp.set(q, -1);
ivec alphapow = - ones_i(2);
Gamma = One;
for (j = 0; j < erasure_positions.length(); j++) {
rx[erasure_positions(j)] = rtemp;
alphapow(1) = erasure_positions(j);
Gamma *= (One - GFX(q, alphapow));
}
//Fix the syndrome polynomial S(x).
S.clear();
for (j = 1; j <= 2 * t; j++) {
S[j] = rx(GF(q, b + j - 1));
}
// calculate the modified syndrome polynomial Xi(x) = Gamma * (1+S) - 1
Xi = Gamma * (One + S) - One;
// Apply Berlekam-Massey algorithm
if (Xi.get_true_degree() >= 1) { //Errors in the received word
// Iterate to find Lambda(x), which hold all error locations
kk = 0;
Lambda = One;
L = 0;
T = GFX(q, (char*)"-1 0");
while (kk < 2 * t) {
kk = kk + 1;
tempsum = GF(q, -1);
for (l = 1; l <= L; l++) {
tempsum += Lambda[l] * Xi[kk - l];
}
delta = Xi[kk] - tempsum;
if (delta != GF(q, -1)) {
OldLambda = Lambda;
Lambda -= delta * T;
if (2 * L < kk) {
L = kk - L;
T = OldLambda / delta;
}
}
T = GFX(q, (char*)"-1 0") * T;
}
// Find the zeros to Lambda(x)
errorpos.set_size(Lambda.get_true_degree());
foundzeros = 0;
for (j = q - 2; j >= 0; j--) {
if (Lambda(GF(q, j)) == GF(q, -1)) {
errorpos(foundzeros) = (n - j) % n;
foundzeros += 1;
if (foundzeros >= Lambda.get_true_degree()) {
break;
}
}
}
if (foundzeros != Lambda.get_true_degree()) {
decoderfailure = true;
}
else { // Forney algorithm...
//Compute Omega(x) using the key equation for RS-decoding
Omega.set_degree(2 * t);
Omegatemp = Lambda * (One + Xi);
for (j = 0; j <= 2 * t; j++) {
Omega[j] = Omegatemp[j];
}
//Find the error/erasure magnitude polynomial by treating them the same
Psiprime = formal_derivate(Lambda*Gamma);
errorpos = concat(errorpos, erasure_positions);
ex.clear();
for (j = 0; j < errorpos.length(); j++) {
Xk = GF(q, errorpos(j));
Xkinv = GF(q, 0) / Xk;
// we calculate ex = - error polynomial, in order to avoid the
// subtraction when recunstructing the corrected codeword
ex[errorpos(j)] = (Xk * Omega(Xkinv)) / Psiprime(Xkinv);
if (b != 1) { // non-narrow-sense code needs corrected error magnitudes
int correction_exp = ( errorpos(j)*(1-b) ) % n;
ex[errorpos(j)] *= GF(q, correction_exp + ( (correction_exp < 0) ? n : 0 ));
}
}
//Reconstruct the corrected codeword.
// instead of subtracting the error/erasures, we calculated
// the negative error with 'ex' above
cx = rx + ex;
//Code word validation
S.clear();
for (j = 1; j <= 2 * t; j++) {
S[j] = cx(GF(q, b + j - 1));
}
if (S.get_true_degree() >= 1) {
decoderfailure = true;
}
}
}
else {
cx = rx;
decoderfailure = false;
}
//Find the message polynomial
mbit.clear();
if (decoderfailure == false) {
if (cx.get_true_degree() >= 1) { // A nonzero codeword was transmitted
if (systematic) {
for (j = 0; j < k; j++) {
mx[j] = cx[j];
}
}
else {
mx = divgfx(cx, g);
}
for (j = 0; j <= mx.get_true_degree(); j++) {
mbit.replace_mid(j * m, mx[j].get_vectorspace());
}
}
}
else { //Decoder failure.
// for a systematic code it is better to extract the undecoded message
// from the received code word, i.e. obtaining a bit error
// prob. p_b << 1/2, than setting all-zero (p_b = 1/2)
if (systematic) {
mbit = coded_bits.mid(i * n * m, k * m);
}
else {
mbit = zeros_b(k);
}
no_dec_failure = false;
}
decoded_message.replace_mid(i * m * k, mbit);
cw_isvalid(i) = (!decoderfailure);
}
return no_dec_failure;
}
