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/*!
* \file
* \brief Implementation of binary sequence classes and functions
* \author Tony Ottosson and Pal Frenger
*
* -------------------------------------------------------------------------
*
* Copyright (C) 1995-2010 (see AUTHORS file for a list of contributors)
*
* This file is part of IT++ - a C++ library of mathematical, signal
* processing, speech processing, and communications classes and functions.
*
* IT++ is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* IT++ is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along
* with IT++. If not, see <http://www.gnu.org/licenses/>.
*
* -------------------------------------------------------------------------
*/
#include <itpp/comm/sequence.h>
#include <itpp/base/converters.h>
#include <itpp/base/math/log_exp.h>
namespace itpp
{
LFSR::LFSR(const bvec &connections)
{
set_connections(connections);
}
LFSR::LFSR(const ivec &connections)
{
set_connections(connections);
}
void LFSR::set_connections(const bvec &connections)
{
int N = connections.size() - 1;
memory.set_size(N, true); // Should this be true???
Connections = connections.right(N);
}
void LFSR::set_connections(const ivec &connections)
{
bvec temp = oct2bin(connections);
int N = temp.size() - 1;
memory.set_size(N, true); // Should this be true???
Connections = temp.right(N);
}
void LFSR::set_state(const bvec &state)
{
it_assert(state.length() == memory.size(), "LFSR::set_state(): dimension mismatch");
memory = state;
}
void LFSR::set_state(const ivec &state)
{
bvec temp = oct2bin(state, 1);
it_assert(temp.length() >= memory.size(), "LFSR::set_state(): dimension mismatch");
memory = temp.right(memory.size());
}
bvec LFSR::shift(int no_shifts)
{
it_assert(no_shifts > 0, "LFSR::shift(): shift must be positive");
bvec temp(no_shifts);
for (int i = 0;i < no_shifts;i++) {
temp(i) = shift();
}
return temp;
}
//--------------------------- class Gold -------------------------
Gold::Gold(int degree)
{
bvec mseq1_connections, mseq2_connections;
switch (degree) {
case 5:
mseq1_connections = bvec("1 0 1 0 0 1");
mseq2_connections = bvec("1 0 1 1 1 1");
break;
case 7:
mseq1_connections = bvec("1 0 0 1 0 0 0 1");
mseq2_connections = bvec("1 1 1 1 0 0 0 1");
break;
case 8:
mseq1_connections = bvec("1 1 1 0 0 1 1 1 1");
mseq2_connections = bvec("1 1 0 0 0 0 1 1 1");
break;
case 9:
mseq1_connections = bvec("1 0 0 0 1 0 0 0 0 1");
mseq2_connections = bvec("1 0 0 1 1 0 1 0 0 1");
break;
default:
it_error("This degree of Gold sequence is not available");
}
mseq1.set_connections(mseq1_connections);
mseq2.set_connections(mseq2_connections);
N = pow2i(mseq1.get_length()) - 1;
}
Gold::Gold(const bvec &mseq1_connections, const bvec &mseq2_connections)
{
it_assert(mseq1_connections.size() == mseq2_connections.size(), "Gold::Gold(): dimension mismatch");
mseq1.set_connections(mseq1_connections);
mseq2.set_connections(mseq2_connections);
N = pow2i(mseq1.get_length()) - 1;
}
Gold::Gold(const ivec &mseq1_connections, const ivec &mseq2_connections)
{
mseq1.set_connections(mseq1_connections);
mseq2.set_connections(mseq2_connections);
it_assert(mseq1.get_length() == mseq1.get_length(), "Gold::Gold(): dimension mismatch");
N = pow2i(mseq1.get_length()) - 1;
}
void Gold::set_state(const bvec &state1, const bvec &state2)
{
mseq1.set_state(state1);
mseq2.set_state(state2);
}
void Gold::set_state(const ivec &state1, const ivec &state2)
{
mseq1.set_state(state1);
mseq2.set_state(state2);
}
bvec Gold::shift(int no_shifts)
{
it_assert(no_shifts > 0, "Gold::shift(): shift must be positive");
bvec temp(no_shifts);
for (int i = 0;i < no_shifts;i++) {
temp(i) = shift();
}
return temp;
}
bmat Gold::get_family(void)
{
bmat codes(N + 2, N);
bvec temp = dec2bin(mseq1.get_length(), 1);
set_state(temp, temp);
// The two m-seq.
codes.set_row(0, mseq1.shift(N));
codes.set_row(1, mseq2.shift(N));
// The sum of mseq1 and all time shifts of mseq2
for (int i = 0;i < N;i++) {
codes.set_row(i + 2, codes.get_row(0) + concat((codes.get_row(1)).right(i), (codes.get_row(1)).left(N - i)));
}
return codes;
}
smat wcdma_spreading_codes(int SF)
{
it_assert((SF == 1) || (SF == 2) || (SF == 4) || (SF == 8) || (SF == 16) || (SF == 32) || (SF == 64) || (SF == 128) || (SF == 256) || (SF == 512),
"wcdma_spreading_codes: SF must equal 1, 2, 4, 8, 16, 32, 64, 128, 256, or 512");
smat codes(SF, SF);
if (SF == 1) {
codes(0, 0) = short(1);
}
else {
int i;
smat prev_codes(SF / 2, SF / 2);
prev_codes = wcdma_spreading_codes(SF / 2);
for (i = 0; i < SF / 2; i++) {
codes.set_row(2*i, concat(prev_codes.get_row(i), prev_codes.get_row(i)));
codes.set_row(2*i + 1, concat(prev_codes.get_row(i), (-prev_codes.get_row(i))));
}
}
return codes;
}
} // namespace itpp
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