Merge pull request ARMmbed#2008 from ARMmbed/IOTTHD-3234

MAC: Increase backoff exponent when retry count grows
artokin · Mar 12, 2019 · a0e893b · a0e893b
2 parents 274abdd + ae91f87
commit a0e893b
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/source/MAC/IEEE802_15_4/mac_pd_sap.c b/source/MAC/IEEE802_15_4/mac_pd_sap.c
@@ -355,6 +355,10 @@ static void mac_sap_no_ack_cb(protocol_interface_rf_mac_setup_s *rf_ptr)
         rf_ptr->mac_cca_retry = 0;
         rf_ptr->mac_tx_retry++; //Update retry counter
         mac_csma_param_init(rf_ptr);
+        // Increase current backoff exponent when retry count grows
+        for (int retry_index = rf_ptr->mac_tx_retry; retry_index > 0; retry_index--) {
+            mac_csma_BE_update(rf_ptr);
+        }
         rf_ptr->mac_tx_status.retry++;
         /*Send retry using random interval*/
         if (mcps_pd_data_rebuild(rf_ptr, rf_ptr->active_pd_data_request)) {