modified RSL calculation and value in messaging

DEVICE_MIN_SENS is changed to uint8_t and value given as -174 to 80 dbm
RSL_IE write is now given as uint8

Separated function to validate min sensitivity if default is incorrect
Added RSL from DBm calculation function
Removed the extra EAPOL wait if links are not above treshold

Author: Mika Tervonen

source/6LoWPAN/ws/ws_bootstrap.c

@@ -910,13 +910,13 @@ static void ws_bootstrap_pan_advertisement_analyse(struct protocol_interface_inf
         if (memcmp(cur->ws_info->parent_info.addr, ADDR_UNSPECIFIED, 8) != 0) {
 
             // if we dont have higher than threshold signal only signal level decides parent
-            if (ws_neighbor_class_rssi_from_dbm_calculate(cur->ws_info->parent_info.signal_dbm) < (CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS) &&
-                    ws_neighbor_class_rssi_from_dbm_calculate(data->signal_dbm) > ws_neighbor_class_rssi_from_dbm_calculate(cur->ws_info->parent_info.signal_dbm)) {
+            if (ws_neighbor_class_rsl_from_dbm_calculate(cur->ws_info->parent_info.signal_dbm) < (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS) &&
+                    ws_neighbor_class_rsl_from_dbm_calculate(data->signal_dbm) > ws_neighbor_class_rsl_from_dbm_calculate(cur->ws_info->parent_info.signal_dbm)) {
                 // automatically select the best quality link from the below threshold
                 goto parent_selected;
             }
             // Drop if signal quality is not good enough
-            if (ws_neighbor_class_rssi_from_dbm_calculate(data->signal_dbm) < (CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS)) {
+            if (ws_neighbor_class_rsl_from_dbm_calculate(data->signal_dbm) < (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS)) {
                 tr_info("EAPOL target dropped Link quality too low");
                 return;
             }
@@ -935,14 +935,6 @@ static void ws_bootstrap_pan_advertisement_analyse(struct protocol_interface_inf
                 tr_info("EAPOL target dropped Lower link quality %u < %u current", data->signal_dbm, cur->ws_info->parent_info.signal_dbm);
                 return;
             }
-
-        } else {
-            // First advertise heard
-
-            if (ws_neighbor_class_rssi_from_dbm_calculate(data->signal_dbm) < (CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS)) {
-                // First neighbor is too low we need to wait one extra trickle
-                cur->bootsrap_state_machine_cnt += cur->ws_info->trickle_params_pan_discovery.Imin + randLIB_get_8bit() % 50;
-            }
         }
 
 parent_selected:

source/6LoWPAN/ws/ws_common.c

@@ -35,7 +35,9 @@
 #ifdef HAVE_WS
 #define TRACE_GROUP "wscm"
 
-int8_t DEVICE_MIN_SENS = -93;
+// estimated sensitivity -93 dbm converted to Wi-SUN RSL range
+// This provides a range of -174 (0) to +80 (254) dBm
+uint8_t DEVICE_MIN_SENS = 174 - 93;
 
 #define TRICKLE_IMIN_60_SECS (60 * 10)
 #define TRICKLE_IMIN_30_SECS (30 * 10)

source/6LoWPAN/ws/ws_config.h

@@ -68,7 +68,7 @@
  *
  * Default value for us is -93
  */
-extern int8_t DEVICE_MIN_SENS;
+extern uint8_t DEVICE_MIN_SENS;
 
 /* Candidate parent Threshold
  */

source/6LoWPAN/ws/ws_ie_lib.c

@@ -111,10 +111,10 @@ uint8_t *ws_wh_fc_write(uint8_t *ptr, uint8_t flow_ctrl)
     return ptr;
 }
 
-uint8_t *ws_wh_rsl_write(uint8_t *ptr, int8_t rssi)
+uint8_t *ws_wh_rsl_write(uint8_t *ptr, uint8_t rsl)
 {
     ptr = ws_wh_header_base_write(ptr, 1, WH_IE_RSL_TYPE);
-    *ptr++ = rssi;
+    *ptr++ = rsl;
     return ptr;
 }
 

source/6LoWPAN/ws/ws_ie_lib.h

@@ -36,7 +36,7 @@ typedef struct ws_wp_network_name {
 uint8_t *ws_wh_utt_write(uint8_t *ptr, uint8_t message_type);
 uint8_t *ws_wh_bt_write(uint8_t *ptr);
 uint8_t *ws_wh_fc_write(uint8_t *ptr, uint8_t flow_ctrl);
-uint8_t *ws_wh_rsl_write(uint8_t *ptr, int8_t rssi);
+uint8_t *ws_wh_rsl_write(uint8_t *ptr, uint8_t rsl);
 uint8_t *ws_wh_vh_write(uint8_t *ptr, uint8_t *vendor_header, uint8_t vendor_header_length);
 uint8_t *ws_wh_ea_write(uint8_t *ptr, uint8_t *eui64);
 

source/6LoWPAN/ws/ws_llc_data_service.c

@@ -463,8 +463,7 @@ static void ws_llc_ack_data_req_ext(const mac_api_t *api, mcps_ack_data_payload_
     //Write Data to block
     uint8_t *ptr = base->ws_enhanced_ack_elements;
     ptr = ws_wh_utt_write(ptr, WS_FT_ACK);
-    uint8_t rsl = ws_neighbor_class_rssi_from_dbm_calculate(rssi);
-    ws_wh_rsl_write(ptr, rsl);
+    ws_wh_rsl_write(ptr, ws_neighbor_class_rsl_from_dbm_calculate(rssi));
 }
 
 /** WS LLC MAC data extension indication  */

source/6LoWPAN/ws/ws_neighbor_class.c

@@ -134,13 +134,22 @@ void ws_neighbor_class_neighbor_broadcast_schedule_set(ws_neighbor_class_entry_t
     ws_neighbor->fhss_data.bc_timing_info.broadcast_schedule_id = ws_bs_ie->broadcast_schedule_identifier;
 }
 
-uint8_t ws_neighbor_class_rssi_from_dbm_calculate(int8_t dbm_heard)
+void ws_neighbor_class_rf_sensitivity_calculate(uint8_t rsl_heard)
 {
-    if (DEVICE_MIN_SENS > dbm_heard) {
+    if (DEVICE_MIN_SENS > rsl_heard) {
         // We are hearing packet with lower than min_sens dynamically learn the sensitivity
-        DEVICE_MIN_SENS = dbm_heard;
+        DEVICE_MIN_SENS = rsl_heard;
     }
-    return dbm_heard - DEVICE_MIN_SENS;
+}
+
+uint8_t ws_neighbor_class_rsl_from_dbm_calculate(int8_t dbm_heard)
+{
+    /* RSL MUST be calculated as the received signal level relative to standard
+     * thermal noise (290oK) at 1 Hz bandwidth or 174 dBm.
+     * This provides a range of -174 (0) to +80 (254) dBm.
+     */
+
+    return dbm_heard + 174;
 }
 
 static void ws_neighbor_class_parent_set_analyze(ws_neighbor_class_entry_t *ws_neighbor)
@@ -151,24 +160,26 @@ static void ws_neighbor_class_parent_set_analyze(ws_neighbor_class_entry_t *ws_n
         return;
     }
 
-    if (ws_neighbor_class_rsl_in_get(ws_neighbor) < (CAND_PARENT_THRESHOLD - CAND_PARENT_HYSTERISIS) &&
-            ws_neighbor_class_rsl_out_get(ws_neighbor) < (CAND_PARENT_THRESHOLD - CAND_PARENT_HYSTERISIS)) {
+    if (ws_neighbor_class_rsl_in_get(ws_neighbor) < (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD - CAND_PARENT_HYSTERISIS) &&
+            ws_neighbor_class_rsl_out_get(ws_neighbor) < (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD - CAND_PARENT_HYSTERISIS)) {
         ws_neighbor->candidate_parent = false;
     }
 
-    if (ws_neighbor_class_rsl_in_get(ws_neighbor) > (CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS) &&
-            ws_neighbor_class_rsl_out_get(ws_neighbor) > (CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS)) {
+    if (ws_neighbor_class_rsl_in_get(ws_neighbor) > (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS) &&
+            ws_neighbor_class_rsl_out_get(ws_neighbor) > (DEVICE_MIN_SENS + CAND_PARENT_THRESHOLD + CAND_PARENT_HYSTERISIS)) {
         ws_neighbor->candidate_parent = true;
     }
 }
 
 void ws_neighbor_class_rsl_in_calculate(ws_neighbor_class_entry_t *ws_neighbor, int8_t dbm_heard)
 {
-    uint8_t rssi = ws_neighbor_class_rssi_from_dbm_calculate(dbm_heard);
+    uint8_t rsl = ws_neighbor_class_rsl_from_dbm_calculate(dbm_heard);
+    // Calculate minimum sensitivity from heard packets.
+    ws_neighbor_class_rf_sensitivity_calculate(rsl);
     if (ws_neighbor->rsl_in == RSL_UNITITIALIZED) {
-        ws_neighbor->rsl_in = rssi << WS_RSL_SCALING;
+        ws_neighbor->rsl_in = rsl << WS_RSL_SCALING;
     }
-    ws_neighbor->rsl_in = ws_neighbor->rsl_in + rssi - (ws_neighbor->rsl_in >> WS_RSL_SCALING);
+    ws_neighbor->rsl_in = ws_neighbor->rsl_in + rsl - (ws_neighbor->rsl_in >> WS_RSL_SCALING);
     ws_neighbor_class_parent_set_analyze(ws_neighbor);
     return;
 }

source/6LoWPAN/ws/ws_neighbor_class.h

@@ -134,15 +134,26 @@ void ws_neighbor_class_neighbor_broadcast_time_info_update(ws_neighbor_class_ent
 void ws_neighbor_class_neighbor_broadcast_schedule_set(ws_neighbor_class_entry_t *ws_neighbor, ws_bs_ie_t *ws_bs_ie);
 
 /**
- * ws_neighbor_class_rssi_from_dbm_calculate
+ * ws_neighbor_class_rf_sensitivity_calculate
  *
- * Calculates rssi value from dbm heard taking into account min sensitivity of radio
- * dynamically adjusts min sensitivity if value is not properly set
+ * Calculates minimum heard RSL value from all packets.
+ * This will dynamically adjusts min sensitivity if value is not properly set
+ *
+ * \param rsl_heard; rsl_heard heard from Radio
+ *
+ */
+void ws_neighbor_class_rf_sensitivity_calculate(uint8_t rsl_heard);
+
+/**
+ * ws_neighbor_class_rsl_from_dbm_calculate
+ *
+ * Calculates rsl value from dbm heard.
+ * This provides a range of -174 (0) to +80 (254) dBm.
  *
  * \param dbm_heard; dbm heard from the neighbour
  *
  */
-uint8_t ws_neighbor_class_rssi_from_dbm_calculate(int8_t dbm_heard);
+uint8_t ws_neighbor_class_rsl_from_dbm_calculate(int8_t dbm_heard);
 
 /** Helper macros to read RSL values from neighbour class.
  *

test/nanostack/unittest/stub/ws_ie_lib_stub.c

@@ -69,7 +69,7 @@ uint8_t *ws_wh_fc_write(uint8_t *ptr, uint8_t flow_ctrl)
     return ptr;
 }
 
-uint8_t *ws_wh_rsl_write(uint8_t *ptr, int8_t rssi)
+uint8_t *ws_wh_rsl_write(uint8_t *ptr, uint8_t rsl)
 {
     ptr += 4;
     return ptr;

test/nanostack/unittest/stub/ws_neighbour_class_stub.c

@@ -90,7 +90,12 @@ void ws_neighbor_class_neighbor_broadcast_schedule_set(ws_neighbor_class_entry_t
 {
 
 }
-uint8_t ws_neighbor_class_rssi_from_dbm_calculate(int8_t dbm_heard)
+void ws_neighbor_class_rf_sensitivity_calculate(uint8_t rsl_heard)
+{
+
+}
+
+uint8_t ws_neighbor_class_rsl_from_dbm_calculate(int8_t dbm_heard)
 {
     return 0;
 }