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openairinterface5g/openair1/PHY/LTE_TRANSPORT/dlsch_scrambling.c
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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
*
* 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
*/
/*! \file PHY/LTE_TRANSPORT/dlsch_scrambling.c
* \brief Routines for the scrambling procedure of the PDSCH physical channel from 36-211, V8.6 2009-03
* \author R. Knopp
* \date 2011
* \version 0.1
* \company Eurecom
* \email: knopp@eurecom.fr,florian.kaltenberger@eurecom.fr
* \note
* \warning
*/
//#define DEBUG_SCRAMBLING 1
#include "PHY/defs_eNB.h"
#include "PHY/defs_UE.h"
#include "PHY/CODING/coding_extern.h"
#include "PHY/CODING/lte_interleaver_inline.h"
#include "transport_eNB.h"
#include "PHY/phy_extern.h"
#include "UTIL/LOG/vcd_signal_dumper.h"
static inline unsigned int lte_gold_scram(unsigned int *x1, unsigned int *x2, unsigned char reset) __attribute__((always_inline));
static inline unsigned int lte_gold_scram(unsigned int *x1, unsigned int *x2, unsigned char reset)
{
int n;
if (reset) {
*x1 = 1+ (1<<31);
*x2=*x2 ^ ((*x2 ^ (*x2>>1) ^ (*x2>>2) ^ (*x2>>3))<<31);
// skip first 50 double words (1600 bits)
// printf("n=0 : x1 %x, x2 %x\n",x1,x2);
for (n=1; n<50; n++) {
*x1 = (*x1>>1) ^ (*x1>>4);
*x1 = *x1 ^ (*x1<<31) ^ (*x1<<28);
*x2 = (*x2>>1) ^ (*x2>>2) ^ (*x2>>3) ^ (*x2>>4);
*x2 = *x2 ^ (*x2<<31) ^ (*x2<<30) ^ (*x2<<29) ^ (*x2<<28);
}
}
*x1 = (*x1>>1) ^ (*x1>>4);
*x1 = *x1 ^ (*x1<<31) ^ (*x1<<28);
*x2 = (*x2>>1) ^ (*x2>>2) ^ (*x2>>3) ^ (*x2>>4);
*x2 = *x2 ^ (*x2<<31) ^ (*x2<<30) ^ (*x2<<29) ^ (*x2<<28);
return(*x1^*x2);
// printf("n=%d : c %x\n",n,x1^x2);
}
void dlsch_scrambling(LTE_DL_FRAME_PARMS *frame_parms,
int mbsfn_flag,
LTE_eNB_DLSCH_t *dlsch,
int harq_pid,
int G,
uint8_t q,
uint16_t frame,
uint8_t Ns)
{
int n;
// uint8_t reset;
uint32_t x1, x2, s=0;
uint8_t *dlsch_e=dlsch->harq_processes[harq_pid]->e;
uint8_t *e=dlsch_e;
VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_ENB_DLSCH_SCRAMBLING, VCD_FUNCTION_IN);
#ifdef Rel14
// Rule for accumulation of subframes for BL/CE UEs
uint8_t Nacc=4;
uint16_t j0,j,idelta;
uint16_t i = (Ns>>1) + (10*frame);
uint16_t i0 = dlsch->i0;
if (dlsch->sib1_br_flag==1) Nacc=1;
else if (dlsch->rnti == 0xFFFF || dlsch->rnti == 0xFFFE) Nacc = (frame_parms->frame_type == TDD) ? 10 : 4;
// Note: above SC-RNTI will also have to be added when/if implemented
else if (dlsch->CEmode == CEmodeA) Nacc=1;
else if (dlsch->CEmode == CEmodeB) Nacc = (frame_parms->frame_type == TDD) ? 10 : 4;
if (frame_parms->frame_type == FDD || Nacc == 1) idelta = 0;
else idelta = Nacc-2;
j0 = (i0+idelta)/Nacc;
j = (i - i0)/Nacc;
#endif
// reset = 1;
// x1 is set in lte_gold_generic
if (mbsfn_flag == 0) {
#ifdef Rel14
if (dlsch->i0 != 0xFFFF) {
// rule for BL/CE UEs from Section 6.3.1 in 36.211
x2= (dlsch->rnti<<14) + (q<<13) + ((((j0+j)*Nacc)%10)<<9) + frame_parms->Nid_cell;
if ((frame&1023) < 200) LOG_D(PHY,"Scrambling init for (i0 %d, i %d, j0 %d, j %d, Nacc %d) => x2 %d\n",i0,i,j0,j,Nacc,x2);
}
else
#endif
x2 = (dlsch->rnti<<14) + (q<<13) + ((Ns>>1)<<9) + frame_parms->Nid_cell; //this is c_init in 36.211 Sec 6.3.1 for PDSCH
} else {
x2 = ((Ns>>1)<<9) + frame_parms->Nid_cell_mbsfn; //this is c_init in 36.211 Sec 6.3.1 for PMCH
}
#ifdef DEBUG_SCRAMBLING
#ifdef Rel14
printf("scrambling: i0 %d rnti %x, q %d, Ns %d, Nid_cell %d, G %d x2 %x\n",dlsch->i0,dlsch->rnti,q,Ns,frame_parms->Nid_cell, G, x2);
#else
printf("scrambling: rnti %x, q %d, Ns %d, Nid_cell %d, G %d x2 %x\n",dlsch->rnti,q,Ns,frame_parms->Nid_cell, G, x2);
#endif
#endif
s = lte_gold_scram(&x1, &x2, 1);
for (n=0; n<(1+(G>>5)); n++) {
#ifdef DEBUG_SCRAMBLING
for (int k=0;k<32;k++) printf("scrambling %d : %d xor %d = %d\n",k+(n<<5),e[k],(s>>k)&1,e[k]^((s>>k)&1));
#endif
e[0] = (e[0]) ^ (s&1);
e[1] = (e[1]) ^ ((s>>1)&1);
e[2] = (e[2]) ^ ((s>>2)&1);
e[3] = (e[3]) ^ ((s>>3)&1);
e[4] = (e[4]) ^ ((s>>4)&1);
e[5] = (e[5]) ^ ((s>>5)&1);
e[6] = (e[6]) ^ ((s>>6)&1);
e[7] = (e[7]) ^ ((s>>7)&1);
e[8] = (e[8]) ^ ((s>>8)&1);
e[9] = (e[9]) ^ ((s>>9)&1);
e[10] = (e[10]) ^ ((s>>10)&1);
e[11] = (e[11]) ^ ((s>>11)&1);
e[12] = (e[12]) ^ ((s>>12)&1);
e[13] = (e[13]) ^ ((s>>13)&1);
e[14] = (e[14]) ^ ((s>>14)&1);
e[15] = (e[15]) ^ ((s>>15)&1);
e[16] = (e[16]) ^ ((s>>16)&1);
e[17] = (e[17]) ^ ((s>>17)&1);
e[18] = (e[18]) ^ ((s>>18)&1);
e[19] = (e[19]) ^ ((s>>19)&1);
e[20] = (e[20]) ^ ((s>>20)&1);
e[21] = (e[21]) ^ ((s>>21)&1);
e[22] = (e[22]) ^ ((s>>22)&1);
e[23] = (e[23]) ^ ((s>>23)&1);
e[24] = (e[24]) ^ ((s>>24)&1);
e[25] = (e[25]) ^ ((s>>25)&1);
e[26] = (e[26]) ^ ((s>>26)&1);
e[27] = (e[27]) ^ ((s>>27)&1);
e[28] = (e[28]) ^ ((s>>28)&1);
e[29] = (e[29]) ^ ((s>>29)&1);
e[30] = (e[30]) ^ ((s>>30)&1);
e[31] = (e[31]) ^ ((s>>31)&1);
// This is not faster for some unknown reason
// ((__m128i *)e)[0] = _mm_xor_si128(((__m128i *)e)[0],((__m128i *)scrambling_lut)[s&65535]);
// ((__m128i *)e)[1] = _mm_xor_si128(((__m128i *)e)[1],((__m128i *)scrambling_lut)[s>>16]);
s = lte_gold_scram(&x1, &x2, 0);
e += 32;
}
VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_ENB_DLSCH_SCRAMBLING, VCD_FUNCTION_OUT);
}
void init_scrambling_lut(void) {
uint32_t s;
int i=0,j;
for (s=0;s<=65535;s++) {
for (j=0;j<16;j++) {
scrambling_lut[i++] = (uint8_t)((s>>j)&1);
}
}
}
void dlsch_unscrambling(LTE_DL_FRAME_PARMS *frame_parms,
int mbsfn_flag,
LTE_UE_DLSCH_t *dlsch,
int G,
int16_t* llr,
uint8_t q,
uint8_t Ns)
{
int i,j,k=0;
// uint8_t reset;
uint32_t x1, x2, s=0;
// reset = 1;
// x1 is set in first call to lte_gold_generic
if (mbsfn_flag == 0)
x2 = (dlsch->rnti<<14) + (q<<13) + ((Ns>>1)<<9) + frame_parms->Nid_cell; //this is c_init in 36.211 Sec 6.3.1
else
x2 = ((Ns>>1)<<9) + frame_parms->Nid_cell_mbsfn; //this is c_init in 36.211 Sec 6.3.1
#ifdef DEBUG_SCRAMBLING
printf("unscrambling: rnti %x, q %d, Ns %d, Nid_cell %d G %d, x2 %x\n",dlsch->rnti,q,Ns,frame_parms->Nid_cell,G,x2);
#endif
s = lte_gold_scram(&x1, &x2, 1);
for (i=0; i<(1+(G>>5)); i++) {
for (j=0; j<32; j++,k++) {
#ifdef DEBUG_SCRAMBLING
printf("unscrambling %d : %d xor %d =",k,llr[k],(s>>j)&1);
#endif
llr[k] = ((2*((s>>j)&1))-1)*llr[k];
#ifdef DEBUG_SCRAMBLING
printf("%d\n",llr[k]);
#endif
}
s = lte_gold_scram(&x1, &x2, 0);
}
}
void init_unscrambling_lut(void) {
uint32_t s;
int i=0,j;
for (s=0;s<=65535;s++) {
for (j=0;j<16;j++) {
unscrambling_lut[i++] = (int16_t)((((s>>j)&1)<<1)-1);
}
}
}
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