Parminder Singh
b288eafd1e
FEATURE STATEMENT: - Introduce linear phase error noise model in Uplink at UE - Perform common phase error (CPE) estimation and compensation at gNB SOLUTION: - A linear phase shift model is introduced in simulation. - PTRS symbols are used to perform estimation of CPE from DMRS compensated signal - The estimated values are interpolated in time domain and signal is compensated for the CPE. - PTRS processing is done in Frequency Domain for each symbol in a slot and LLR's are calculated for each symbol accordingly. IMPLEMENTATION: * sim.h/channle_sim.c - Linear Phase Noise Generation model definition. * nr_ul_channel_estimation.c/nr_ul_estimation.h - CPE estimation from PTRS and DMRS compensated signal. * nr_dmrs_rx.c/nr_refsig.h - Regenerate PTRS symbols at gNB. * nr_ulsch_demodulation.c - Removed old PTRS processing code and move to a common PTRS processing function * defs_gNB.h/init.c - New PTRS variables definition and initialization * nr_ulsch_ue.c - Corrected PTRS parameter to get new PTRS symbols for each OFDM symbol TESTING * ulsim.c - Added Phase noise, Enable PTRS signal and verified the output. VERIFICATION - The LLR are rotated back with estimated CPE and no error is observed in scrambling/decoding
43 lines
1.5 KiB
C
43 lines
1.5 KiB
C
/*
|
|
* 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
|
|
*
|
|
* 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 <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
#include <time.h>
|
|
#include "sim.h"
|
|
|
|
|
|
/* linear phase noise model */
|
|
void phase_noise(double ts, int16_t * InRe, int16_t * InIm)
|
|
{
|
|
double fd = 300;//0.01*30000
|
|
static double i=0;
|
|
double real, imag,x ,y;
|
|
i++;
|
|
real = cos(fd * 2 * M_PI * i * ts);
|
|
imag = sin (fd * 2 * M_PI * i * ts);
|
|
x = ((real * (double)InRe[0]) - (imag * (double)InIm[0])) ;
|
|
y= ((real * (double)InIm[0]) + (imag * (double)InRe[0])) ;
|
|
InRe[0]= (int16_t)(x);
|
|
InIm[0]= (int16_t)(y);
|
|
}
|