Fix in DL PRB allocation [Issue-ID: ODUHIGH-380]

[o-du/l2.git] / src / cm / common_def.c

diff --git a/src/cm/common_def.c b/src/cm/common_def.c
index 00b61dc..f3c96ec 100644 (file)
--- a/src/cm/common_def.c
+++ b/src/cm/common_def.c
@@ -23,7 +23,7 @@
  *
  * @details
  *
- *     Function: freqDomRscAllocType0
+ *     Function: fillCoresetFeqDomAllocMap
  *     
  *     This function does allocation in frequency domain resource.
  *     This is a bitmap defining  non-overlapping groups of 6 PRBs in ascending order.
@@ -33,45 +33,55 @@
  *  @param[in]  freqDomain - 6 bytes of info, each bit represents a group of 6 PRB.
  *  @return   void
  **/
-void freqDomRscAllocType0(uint16_t startPrb, uint16_t prbSize, uint8_t *freqDomain)
+void fillCoresetFeqDomAllocMap(uint16_t startPrbGrp, uint16_t numPrbGrp, uint8_t *freqDomain)
 {
-   uint8_t remBits = prbSize; /* each bit represents 6 PRBs */
-   uint8_t firstByte = 1;
-   uint8_t numBits,startBit,byteCount = 5;
+   uint8_t  idx;
+   uint8_t  prbGrpStartBit = 0;
+   uint8_t  numBitsToRightShift = 0;
+   uint64_t mask = 0;
+   uint64_t freqAllocBitMap = 0;
 
-   while(remBits)
+   /* 
+    * Frequency allocation bit string is 45 bits long. Hence using 6 bytes (i.e. 48 bits) to represent it.
+    * Each bit corresponds to a group of 6 RBs.
+    *
+    * For example if a coreset includes PRB 24 to 47, then on dividing the PRBs into group of 6, 
+    * startPrbGrp = 24/6 = 4
+    * numPrbGrp = 24/6 = 4
+    * 
+    * Frequency allocation bit string is 48 bits long i.e. Bit 47...0
+    * Here, Bit 47 represents RB group 0, Bit 46 represent RB group 45 and so on.
+    * Since startPrbGrp = 4 and numPrbGrp = 4, it means RB group 4,5,6 and 7 are used in coreset.
+    * i.e. Bits 43, 42, 42 and 40 are masked to 1 and rest all bits are 0 in bitstring    
+    */
+   prbGrpStartBit = 47; 
+   while(numPrbGrp)
    {
-      /* when the startPrb is not in this byteCount */
-      if(startPrb/8)
-      {
-         startPrb -= 8;
-         byteCount--;
-         continue;
-      }
-
-      /* max bytecount is 6 nearly equal to 45 bits*/
-      if(byteCount >= 6)
-          break;
-
-      /* when we are filling the second byte, then the start should be equal to 0 */
-      if(firstByte)
-         startBit = startPrb;
-      else
-         startBit = 0;
-
-      /* calculate the number of bits to be set in this byte */
-      if((remBits+startPrb) <= 8)
-         numBits = remBits;
-      else
-         numBits = 8 - startBit;
-
-      /* bit operation to set the bits */
-               SET_BITS_MSB((startBit % 8),numBits,freqDomain[byteCount])
-      firstByte = 0;
+      mask = 1;
+      printf("startPrbGrp [%d] numPrbGrp [%d] diff [%d]\n",startPrbGrp, numPrbGrp,  (prbGrpStartBit - startPrbGrp));
+      mask = mask << (prbGrpStartBit - startPrbGrp);
+      freqAllocBitMap = freqAllocBitMap | mask;
+      startPrbGrp++;
+      numPrbGrp--;
+   }
 
-      /* the ramaining bits should be subtracted with the numBits set in this byte */
-      remBits -= numBits;
-      byteCount--;
+   /* Copying 48 LSBs from 64-bit integer to the 45 MSBS in 6-byte array 
+    * The first (left-most / most significant) bit corresponds to the first RB
+    * group in the BWP, and so on
+    */
+   /* On right shifting freqAllocBitMap by 40 bits, the bits 47 to 40 of freqAllocBitMap 
+    * will now become 8-LSB. Copying these 8-bits into freqDomain[].
+    * Now shifting freqAllocBitMap by 32 bits, the bit 39 to 32 of freqAllocBitMap will
+    * now become 8-LSB. Copying these 8-bits into next index of freqDomain.
+    * and so on.
+    */
+   numBitsToRightShift = 40; 
+   mask = 0x0000FF0000000000;
+   for(idx=0; idx<FREQ_DOM_RSRC_SIZE; idx++)
+   {
+      freqDomain[idx] = (freqAllocBitMap & mask) >> numBitsToRightShift;
+      numBitsToRightShift -= 8;
+      mask = mask >> 8;
    }
 }