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/*!
* \file
* \brief Implementation of binary sequence classes and functions
* \author Tony Ottosson and Pal Frenger
*
* -------------------------------------------------------------------------
*
* IT++ - C++ library of mathematical, signal processing, speech processing,
* and communications classes and functions
*
* Copyright (C) 1995-2008 (see AUTHORS file for a list of contributors)
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* -------------------------------------------------------------------------
*/
#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)
{
short 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);
short 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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