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/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Author and copyright: Laurent Thomas, open-cells.com
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance:
* contact@openairinterface.org
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>
#include <errno.h>
#include <common/utils/assertions.h>
#include <common/utils/LOG/log.h>
#include <common/config/config_userapi.h>
#include <openair1/SIMULATION/TOOLS/sim.h>
#include <common/utils/telnetsrv/telnetsrv.h>
#include <common/utils/load_module_shlib.h>
#include "rfsimulator.h"
/*
Legacy study:
The parameters are:
gain&loss (decay, signal power, ...)
either a fixed gain in dB, a target power in dBm or ACG (automatic control gain) to a target average
=> don't redo the AGC, as it was used in UE case, that must have a AGC inside the UE
will be better to handle the "set_gain()" called by UE to apply it's gain (enable test of UE power loop)
lin_amp = pow(10.0,.05*txpwr_dBm)/sqrt(nb_tx_antennas);
a lot of operations in legacy, grouped in one simulation signal decay: txgain*decay*rxgain
multi_path (auto convolution, ISI, ...)
either we regenerate the channel (call again random_channel(desc,0)), or we keep it over subframes
legacy: we regenerate each sub frame in UL, and each frame only in DL
*/
void rxAddInput( const c16_t *input_sig,
c16_t *after_channel_sig,
int rxAnt,
channel_desc_t *channelDesc,
int nbSamples,
uint64_t TS,
uint32_t CirSize
) {
// channelDesc->path_loss_dB should contain the total path gain
// so, in actual RF: tx gain + path loss + rx gain (+antenna gain, ...)
// UE and NB gain control to be added
// Fixme: not sure when it is "volts" so dB is 20*log10(...) or "power", so dB is 10*log10(...)
const double pathLossLinear = pow(10,channelDesc->path_loss_dB/20.0);
// Energy in one sample to calibrate input noise
// the normalized OAI value seems to be 256 as average amplitude (numerical amplification = 1)
const double noise_per_sample = pow(10,channelDesc->noise_power_dB/10.0) * 256;
const int dd = abs(channelDesc->channel_offset);
const int nbTx=channelDesc->nb_tx;
for (int i=0; i<nbSamples; i++) {
struct complex16 *out_ptr=after_channel_sig+i;
struct complexd rx_tmp= {0};
for (int txAnt=0; txAnt < nbTx; txAnt++) {
const struct complexd *channelModel= channelDesc->ch[rxAnt+(txAnt*channelDesc->nb_rx)];
//const struct complex *channelModelEnd=channelModel+channelDesc->channel_length;
for (int l = 0; l<(int)channelDesc->channel_length; l++) {
// let's assume TS+i >= l
// fixme: the rfsimulator current structure is interleaved antennas
// this has been designed to not have to wait a full block transmission
// but it is not very usefull
// it would be better to split out each antenna in a separate flow
// that will allow to mix ru antennas freely
// (X + cirSize) % cirSize to ensure that index is positive
const int idx = ((TS + i - l - dd) * nbTx + txAnt + CirSize) % CirSize;
const struct complex16 tx16 = input_sig[idx];
rx_tmp.r += tx16.r * channelModel[l].r - tx16.i * channelModel[l].i;
rx_tmp.i += tx16.i * channelModel[l].r + tx16.r * channelModel[l].i;
} //l
}
// Fixme: lround(), rount(), ... is detected by valgrind as error, not found why
out_ptr->r += lround(rx_tmp.r*pathLossLinear + noise_per_sample*gaussZiggurat(0.0,1.0));
out_ptr->i += lround(rx_tmp.i*pathLossLinear + noise_per_sample*gaussZiggurat(0.0,1.0));
out_ptr++;
}
if ( (TS*nbTx)%CirSize+nbSamples <= CirSize )
// Cast to a wrong type for compatibility !
LOG_D(HW,"Input power %f, output power: %f, channel path loss %f, noise coeff: %f \n",
10*log10((double)signal_energy((int32_t *)&input_sig[(TS*nbTx)%CirSize], nbSamples)),
10*log10((double)signal_energy((int32_t *)after_channel_sig, nbSamples)),
channelDesc->path_loss_dB,
10*log10(noise_per_sample));
}