From 67ad3677a95b4c997d31ae8e8f62eea00688be99 Mon Sep 17 00:00:00 2001
From: ismagom <gomezi@tcd.ie>
Date: Tue, 22 Sep 2015 17:30:14 +0100
Subject: [PATCH] Initial version of LUT-based rate recovery

---
 srslte/include/srslte/fec/rm_turbo.h |   6 ++
 srslte/lib/fec/src/rm_turbo.c        | 107 ++++++++++++++++++++++++++-
 srslte/lib/fec/test/rm_turbo_test.c  |  66 +++++++++--------
 3 files changed, 144 insertions(+), 35 deletions(-)

diff --git a/srslte/include/srslte/fec/rm_turbo.h b/srslte/include/srslte/fec/rm_turbo.h
index 8d29f5988..609e93e14 100644
--- a/srslte/include/srslte/fec/rm_turbo.h
+++ b/srslte/include/srslte/fec/rm_turbo.h
@@ -77,6 +77,12 @@ SRSLTE_API int srslte_rm_turbo_rx(float *w_buff,
                                   uint32_t rv_idx, 
                                   uint32_t nof_filler_bits);
 
+SRSLTE_API int srslte_rm_turbo_rx_lut(float *input, 
+                                      uint32_t in_len, 
+                                      float *output,
+                                      uint32_t out_len, 
+                                      uint32_t rv_idx, uint32_t cb_idx); 
+
 /* High-level API */
 typedef struct SRSLTE_API {
   
diff --git a/srslte/lib/fec/src/rm_turbo.c b/srslte/lib/fec/src/rm_turbo.c
index e338b7f84..359a6d82c 100644
--- a/srslte/lib/fec/src/rm_turbo.c
+++ b/srslte/lib/fec/src/rm_turbo.c
@@ -50,6 +50,7 @@ static uint32_t interleaver_parity_bits[SRSLTE_NOF_TC_CB_SIZES][2*6148];
 static uint32_t k0_vec[SRSLTE_NOF_TC_CB_SIZES][4][2];
 static bool rm_turbo_tables_generated = false; 
 
+uint32_t table_buffer[6144], table_output[6144];
 
 void srslte_rm_turbo_gentable_systematic(uint32_t *table_bits, uint32_t k0_vec[4][2], uint32_t nrows, int ndummy) {
 
@@ -120,6 +121,7 @@ void srslte_rm_turbo_gentable_parity(uint32_t *table_parity, uint32_t k0_vec[4][
   }
 }
 
+
 void srslte_rm_turbo_gentables() {
   if (!rm_turbo_tables_generated) {
     rm_turbo_tables_generated = true; 
@@ -141,7 +143,9 @@ void srslte_rm_turbo_gentables() {
       srslte_rm_turbo_gentable_systematic(interleaver_systematic_bits[cb_idx], k0_vec[cb_idx], nrows, ndummy);
       srslte_rm_turbo_gentable_parity(interleaver_parity_bits[cb_idx], k0_vec[cb_idx], in_len/3, nrows, ndummy);
     }
-  }
+  }  
+
+  srslte_rm_turbo_gentable_receive(table_buffer, table_output, 132, 0);  
 }
 
 
@@ -289,6 +293,8 @@ int srslte_rm_turbo_rx(float *w_buff, uint32_t w_buff_len, float *input, uint32_
   int d_i, d_j;
   bool isdummy;
 
+  
+  
   nrows = (uint32_t) (out_len / 3 - 1) / NCOLS + 1;
   K_p = nrows * NCOLS;
   if (3 * K_p > w_buff_len) {
@@ -313,7 +319,7 @@ int srslte_rm_turbo_rx(float *w_buff, uint32_t w_buff_len, float *input, uint32_
   N_cb = 3 * K_p;       // TODO: Soft buffer size limitation
   k0 = nrows
       * (2 * (uint32_t) ceilf((float) N_cb / (float) (8 * nrows)) * rv_idx + 2);
-
+      
   k = 0;
   j = 0;
   while (k < in_len) {
@@ -352,10 +358,13 @@ int srslte_rm_turbo_rx(float *w_buff, uint32_t w_buff_len, float *input, uint32_
       } else if (input[k] != SRSLTE_RX_NULL) {
         w_buff[jp] += input[k]; /* soft combine LLRs */
       }
-      k++;
-    }
+t      k++;
+    } 
     j++;
   }
+  
+  //printf("wbuff:\n");
+  //srslte_vec_fprint_f(stdout, w_buff, out_len);
 
   /* interleaving and bit selection */
   for (i = 0; i < out_len / 3; i++) {
@@ -378,9 +387,99 @@ int srslte_rm_turbo_rx(float *w_buff, uint32_t w_buff_len, float *input, uint32_
       }
     }
   }
+
   return 0;
 }
 
+
+
+
+void srslte_rm_turbo_gentable_receive(uint32_t *table_buffer, uint32_t *table_output, uint32_t cb_len, uint32_t rv_idx) 
+{
+  
+  int nrows = (uint32_t) (cb_len / 3 - 1) / NCOLS + 1;
+  int ndummy = nrows*NCOLS - cb_len / 3;
+  if (ndummy < 0) {
+    ndummy = 0;
+  }
+
+  /* Undo bit collection. Account for dummy bits */
+  int N_cb = 3*nrows*NCOLS;   
+  int k0 = nrows*(2*(uint32_t) ceilf((float) N_cb/(float) (8*nrows))*rv_idx+2);
+       
+  printf("cb_len=%d, N_cb=%d, ndummy=%d, nrows=%d\n", cb_len, N_cb, ndummy, nrows);
+
+  int kidx; 
+  int K_p = nrows * NCOLS;
+  int k = 0, jp=0, j=0;  
+  bool isdummy = false; 
+  int d_i, d_j; 
+  while (k < cb_len) {
+    jp = (k0 + j) % N_cb;
+
+    if (jp < K_p || !(jp % 2)) {
+      if (jp >= K_p) {
+        d_i = ((jp - K_p) / 2) / nrows;
+        d_j = ((jp - K_p) / 2) % nrows;
+      } else {
+        d_i = jp / nrows;
+        d_j = jp % nrows;        
+      }      
+      if (d_j * NCOLS + RM_PERM_TC[d_i] >= ndummy) {
+        isdummy = false;
+        if (d_j * NCOLS + RM_PERM_TC[d_i] - ndummy < 0) {
+          isdummy = true;
+        } 
+      } else {
+        isdummy = true;
+      }
+
+    } else {
+      uint32_t jpp = (jp - K_p - 1) / 2;
+      kidx = (RM_PERM_TC[jpp / nrows] + NCOLS * (jpp % nrows) + 1) % K_p;
+      if ((kidx - ndummy) < 0) {
+        isdummy = true;
+      } else {
+        isdummy = false;
+      }      
+    }
+    
+    if (!isdummy) {
+      table_buffer[k] = jp%(3*nrows*NCOLS);
+      k++;
+    }
+    j++;
+  }
+
+  for (int i = 0; i < cb_len / 3; i++) {
+    d_i = (i + ndummy) / NCOLS;
+    d_j = (i + ndummy) % NCOLS;
+    for (j = 0; j < 3; j++) {
+      if (j != 2) {
+        kidx = K_p * j + (j + 1) * (RM_PERM_TC[d_j] * nrows + d_i);
+      } else {
+        k = (i + ndummy - 1) % K_p;
+        if (k < 0)
+          k += K_p;
+        kidx = (k / NCOLS + nrows * RM_PERM_TC[k % NCOLS]) % K_p;
+        kidx = 2 * kidx + K_p + 1;
+      }
+      table_output[kidx] = 3*i+j;
+    }
+  }
+}
+
+int srslte_rm_turbo_rx_lut(float *input, uint32_t in_len, float *output, uint32_t out_len, uint32_t rv_idx, uint32_t cb_idx) 
+{
+
+  for (int i=0;i<in_len;i++) {
+    output[table_output[table_buffer[i%out_len]]] += input[i];
+  }
+  
+  return 0;
+}
+
+
 /** High-level API */
 
 int srslte_rm_turbo_initialize(srslte_rm_turbo_hl* h) {
diff --git a/srslte/lib/fec/test/rm_turbo_test.c b/srslte/lib/fec/test/rm_turbo_test.c
index f05c2d18b..f246a8e64 100644
--- a/srslte/lib/fec/test/rm_turbo_test.c
+++ b/srslte/lib/fec/test/rm_turbo_test.c
@@ -86,18 +86,13 @@ void parse_args(int argc, char **argv) {
 int main(int argc, char **argv) {
   int i;
   uint8_t *bits, *bits_out, *rm_bits, *rm_bits2, *rm_bits2_bytes, *w_buff_c;
-  float *rm_symbols, *unrm_symbols, *w_buff_f;
+  float *rm_symbols, *unrm_symbols, *unrm_symbols2, *w_buff_f;
   int nof_errors;
 
   parse_args(argc, argv);
   
   srslte_rm_turbo_gentables();
 
- for (cb_idx=0;cb_idx<188;cb_idx++) {
-    for (rv_idx=0;rv_idx<4;rv_idx++) {
-      printf("cb_len=%d, rv_idx=%d\n", cb_idx, rv_idx);
-  
-  
   if (cb_idx != -1) {
     nof_tx_bits = 3*srslte_cbsegm_cbsize(cb_idx)+12;
   }
@@ -147,6 +142,11 @@ int main(int argc, char **argv) {
     perror("malloc");
     exit(-1);
   }
+  unrm_symbols2 = malloc(sizeof(float) * nof_tx_bits);
+  if (!unrm_symbols2) {
+    perror("malloc");
+    exit(-1);
+  }
 
   for (i = 0; i < nof_tx_bits; i++) {
     bits[i] = rand() % 2;
@@ -191,38 +191,42 @@ int main(int argc, char **argv) {
 
   srslte_bit_unpack_vector(rm_bits2_bytes, rm_bits2, nof_rx_bits);
   
-  for (int i=0;i<nof_rx_bits;i++) {
-    if (rm_bits[i] != rm_bits2[i]) {
-      printf("error in bit %d\n", i);
-      exit(-1);
-    }
-  }
-  }    
-  }
-  printf("OK\n");
-  exit(0);
-  
-  printf("RM: ");
-  srslte_vec_fprint_b(stdout, rm_bits, nof_rx_bits);
- 
   for (i = 0; i < nof_rx_bits; i++) {
     rm_symbols[i] = (float) rm_bits[i] ? 1 : -1;
   }
+  
+  for (int i=0;i<nof_rx_bits;i++) {
+    rm_symbols[i] = rand()%10-5;
+  }
 
-  srslte_rm_turbo_rx(w_buff_f, nof_rx_bits * 10, rm_symbols, nof_rx_bits, unrm_symbols, nof_tx_bits,
-      rv_idx, nof_filler_bits);
-
-  printf("UMRM: ");
-  srslte_vec_fprint_f(stdout, unrm_symbols, nof_tx_bits);
-
+  bzero(w_buff_f, nof_rx_bits*10*sizeof(float));
+  struct timeval t[3];
+  gettimeofday(&t[1], NULL);
+  srslte_rm_turbo_rx(w_buff_f, nof_rx_bits * 10, rm_symbols, nof_rx_bits, unrm_symbols, nof_tx_bits, rv_idx, 0);
+  gettimeofday(&t[2], NULL);
+  get_time_interval(t);
+  printf("Old=%d us\n", t[0].tv_usec);
+  
+  bzero(unrm_symbols2, nof_tx_bits*sizeof(float));
+  gettimeofday(&t[1], NULL);
+  srslte_rm_turbo_rx_lut(rm_symbols, nof_rx_bits, unrm_symbols2, nof_tx_bits, rv_idx, cb_idx);
+  gettimeofday(&t[2], NULL);
+  get_time_interval(t);
+  printf("New=%d us\n", t[0].tv_usec);
+  
+  for (int i=0;i<nof_tx_bits;i++) {
+    if (unrm_symbols[i] != unrm_symbols2[i]) {
+      printf("error in bit %d %f!=%f\n", i, unrm_symbols[i], unrm_symbols2[i]);
+      exit(-1);
+    }
+  }
+ 
+  printf("Ok\n");
+  exit(0);
+  
   for (i=0;i<nof_tx_bits;i++) {
     bits_out[i] = unrm_symbols[i]>0?1:0;
   }
-  printf("BITS: ");
-  srslte_vec_fprint_b(stdout, bits_out, nof_tx_bits);
-  printf("BITS: ");
-  srslte_vec_fprint_b(stdout, bits, nof_tx_bits);
-
   nof_errors = 0;
   for (i = 0; i < nof_tx_bits; i++) {
     if (bits_out[i] != bits[i]) {