bugfix: fix UL over scheduling

There is too much UL scheduling because the buffer status is
overestimated.

This commit tries to make things simpler.

openair2/LAYER2/MAC/defs.h

@@ -665,7 +665,7 @@ typedef struct {
     /// mcs from last UL scheduling
     uint8_t mcs_UL[8];
     /// TBS from last UL scheduling
-    uint8_t TBS_UL[8];
+    int TBS_UL[8];
     /// Flag to indicate UL has been scheduled at least once
     boolean_t ul_active;
     /// Flag to indicate UE has been configured (ACK from RRCConnectionSetup received)
@@ -720,9 +720,6 @@ typedef struct {
 
     // Logical channel info for link with RLC
 
-    /// Last received UE BSR info for each logical channel group id
-    uint8_t bsr_info[MAX_NUM_LCGID];
-
     /// LCGID mapping
     long lcgidmap[11];
 
@@ -749,8 +746,6 @@ typedef struct {
     /// size of remaining size to send for the downlink head SDU
     uint32_t dl_buffer_head_sdu_remaining_size_to_send[MAX_NUM_LCID];
 
-    /// total uplink buffer size 
-    uint32_t ul_total_buffer;
     /// uplink buffer creation time for each LCID
     uint32_t ul_buffer_creation_time[MAX_NUM_LCGID];
     /// maximum uplink buffer creation time across all the LCIDs
@@ -758,6 +753,11 @@ typedef struct {
     /// uplink buffer size per LCID
     uint32_t ul_buffer_info[MAX_NUM_LCGID];
 
+    /// uplink bytes that are currently scheduled
+    int scheduled_ul_bytes;
+    /// estimation of the UL buffer size
+    int estimated_ul_buffer;
+
     /// UE tx power
     int32_t ue_tx_power;
 

openair2/LAYER2/MAC/eNB_scheduler_primitives.c

@@ -2483,14 +2483,15 @@ UE_is_to_be_scheduled(module_id_t module_idP, int CC_id, uint8_t UE_id)
     LOG_D(MAC, "[eNB %d][PUSCH] Checking UL requirements UE %d/%x\n",
 	  module_idP, UE_id, UE_RNTI(module_idP, UE_id));
 
-    if ((UE_template->bsr_info[LCGID0] > 0) || (UE_template->bsr_info[LCGID1] > 0) || (UE_template->bsr_info[LCGID2] > 0) || (UE_template->bsr_info[LCGID3] > 0) || (UE_template->ul_SR > 0) ||	// uplink scheduling request
+    if ((UE_template->scheduled_ul_bytes < UE_template->estimated_ul_buffer) ||
+        (UE_template->ul_SR > 0) ||	// uplink scheduling request
 	((UE_sched_ctl->ul_inactivity_timer > 20) && (UE_sched_ctl->ul_scheduled == 0)) ||	// every 2 frames when RRC_CONNECTED
 	((UE_sched_ctl->ul_inactivity_timer > 10) && (UE_sched_ctl->ul_scheduled == 0) && (mac_eNB_get_rrc_status(module_idP, UE_RNTI(module_idP, UE_id)) < RRC_CONNECTED)))	// every Frame when not RRC_CONNECTED
     {
 	LOG_D(MAC,
-	      "[eNB %d][PUSCH] UE %d/%x should be scheduled (BSR0 %d,SR %d)\n",
+	      "[eNB %d][PUSCH] UE %d/%x should be scheduled (SRB0 estimated size %d,SR %d)\n",
 	      module_idP, UE_id, UE_RNTI(module_idP, UE_id),
-	      UE_template->bsr_info[LCGID0], UE_template->ul_SR);
+	      UE_template->ul_buffer_info[LCGID0], UE_template->ul_SR);
 	return (1);
     } else {
 	return (0);

openair2/LAYER2/MAC/pre_processor.c

@@ -1590,9 +1590,11 @@ assign_max_mcs_min_rb(module_id_t module_idP, int frameP,
 		to_prb(RC.mac[module_idP]->common_channels[CC_id].
 		       ul_Bandwidth);
 	    // if this UE has UL traffic
-	    if (UE_template->ul_total_buffer > 0) {
-
+            int bytes_to_schedule = UE_template->estimated_ul_buffer - UE_template->scheduled_ul_bytes;
+            if (bytes_to_schedule < 0) bytes_to_schedule = 0;
+            int bits_to_schedule = bytes_to_schedule * 8;
 
+	    if (bits_to_schedule > 0) {
 		tbs = get_TBS_UL(mcs, 3) << 3;	// 1 or 2 PRB with cqi enabled does not work well!
 		rb_table_index = 2;
 
@@ -1602,7 +1604,7 @@ assign_max_mcs_min_rb(module_id_t module_idP, int frameP,
 					 Ncp, 0);
 
 		while ((((UE_template->phr_info - tx_power) < 0)
-			|| (tbs > UE_template->ul_total_buffer))
+			|| (tbs > bits_to_schedule))
 		       && (mcs > 3)) {
 		    // LOG_I(MAC,"UE_template->phr_info %d tx_power %d mcs %d\n", UE_template->phr_info,tx_power, mcs);
 		    mcs--;
@@ -1610,7 +1612,7 @@ assign_max_mcs_min_rb(module_id_t module_idP, int frameP,
 		    tx_power = estimate_ue_tx_power(tbs, rb_table[rb_table_index], 0, Ncp, 0);	// fixme: set use_srs
 		}
 
-		while ((tbs < UE_template->ul_total_buffer) &&
+		while ((tbs < bits_to_schedule) &&
 		       (rb_table[rb_table_index] <
 			(N_RB_UL - first_rb[CC_id]))
 		       && ((UE_template->phr_info - tx_power) > 0)
@@ -1700,11 +1702,14 @@ static int ue_ul_compare(const void *_a, const void *_b, void *_params)
 	UE_list->UE_template[pCCid2][UE_id2].ul_buffer_info[LCGID0])
 	return 1;
 
-    if (UE_list->UE_template[pCCid1][UE_id1].ul_total_buffer >
-	UE_list->UE_template[pCCid2][UE_id2].ul_total_buffer)
+    int bytes_to_schedule1 = UE_list->UE_template[pCCid1][UE_id1].estimated_ul_buffer - UE_list->UE_template[pCCid1][UE_id1].scheduled_ul_bytes;
+    if (bytes_to_schedule1 < 0) bytes_to_schedule1 = 0;
+    int bytes_to_schedule2 = UE_list->UE_template[pCCid2][UE_id2].estimated_ul_buffer - UE_list->UE_template[pCCid2][UE_id2].scheduled_ul_bytes;
+    if (bytes_to_schedule2 < 0) bytes_to_schedule2 = 0;
+
+    if (bytes_to_schedule1 > bytes_to_schedule2)
 	return -1;
-    if (UE_list->UE_template[pCCid1][UE_id1].ul_total_buffer <
-	UE_list->UE_template[pCCid2][UE_id2].ul_total_buffer)
+    if (bytes_to_schedule1 < bytes_to_schedule2)
 	return 1;
 
     if (UE_list->UE_template[pCCid1][UE_id1].pre_assigned_mcs_ul >

openair2/LAYER2/openair2_proc.c

@@ -217,11 +217,11 @@ int dump_eNB_l2_stats(char *buffer, int length)
                        UE_list->eNB_UE_stats[CC_id][UE_id].num_errors_rx);
 
         len+= sprintf(&buffer[len],"[MAC] Received PHR PH = %d (db)\n", UE_list->UE_template[CC_id][UE_id].phr_info);
-        len+= sprintf(&buffer[len],"[MAC] Received BSR LCGID[0][1][2][3] = %u %u %u %u\n",
-                      UE_list->UE_template[CC_id][UE_id].bsr_info[LCGID0],
-                      UE_list->UE_template[CC_id][UE_id].bsr_info[LCGID1],
-                      UE_list->UE_template[CC_id][UE_id].bsr_info[LCGID2],
-                      UE_list->UE_template[CC_id][UE_id].bsr_info[LCGID3]
+        len+= sprintf(&buffer[len],"[MAC] Estimated size LCGID[0][1][2][3] = %u %u %u %u\n",
+                      UE_list->UE_template[CC_id][UE_id].ul_buffer_info[LCGID0],
+                      UE_list->UE_template[CC_id][UE_id].ul_buffer_info[LCGID1],
+                      UE_list->UE_template[CC_id][UE_id].ul_buffer_info[LCGID2],
+                      UE_list->UE_template[CC_id][UE_id].ul_buffer_info[LCGID3]
                      );
       }