FHSS: WS FHSS to use pre-set TX time

Author: Jarkko Paso

nanostack/platform/arm_hal_phy.h

@@ -56,7 +56,7 @@ typedef enum {
     PHY_EXTENSION_READ_LINK_STATUS, /**< Net library could read link status. */
     PHY_EXTENSION_CONVERT_SIGNAL_INFO, /**< Convert signal info. */
     PHY_EXTENSION_ACCEPT_ANY_BEACON, /**< Set boolean true or false for accept beacon from other Pan-ID than configured. Default value should be false */
-    PHY_EXTENSION_SET_TX_TIME,  /**< Net library sets transmission time based on global time stamp. Max. 65ms from setting to TX */
+    PHY_EXTENSION_SET_TX_TIME,  /**< Net library sets transmission time based on global time stamp. Max. 65ms from setting to TX. If TX time is set to zero, it should be ignored.*/
     PHY_EXTENSION_READ_RX_TIME, /**< Read the time of last reception based on global time stamp. */
 } phy_extension_type_e;
 

source/MAC/IEEE802_15_4/mac_header_helper_functions.c

@@ -516,7 +516,7 @@ uint8_t * mac_generic_packet_write(struct protocol_interface_rf_mac_setup *rf_pt
         ptr += buffer->mac_payload_length;
     }
     if (rf_ptr->fhss_api) {
-        rf_ptr->fhss_api->write_synch_info(rf_ptr->fhss_api, ie_start, buffer->headerIeLength, FHSS_DATA_FRAME, 0);
+        rf_ptr->fhss_api->write_synch_info(rf_ptr->fhss_api, ie_start, buffer->headerIeLength, FHSS_DATA_FRAME, buffer->tx_time);
     }
     return ptr;
 }

source/MAC/IEEE802_15_4/mac_mcps_sap.c

@@ -51,6 +51,9 @@
 
 #define TRACE_GROUP "mMCp"
 
+// Used to set TX time (us) with FHSS. Must be <= 65ms.
+#define MAC_TX_PROCESSING_DELAY_INITIAL 2000
+
 typedef struct {
     uint8_t address[8];
     unsigned addr_type:2;
@@ -1362,6 +1365,17 @@ static void mac_security_authentication_data_params_set(ccm_globals_t *ccm_ptr,
     }
 }
 
+static uint32_t mcps_calculate_tx_time(protocol_interface_rf_mac_setup_s *rf_mac_setup, uint16_t time_to_tx)
+{
+    if (!rf_mac_setup->fhss_api) {
+        return 0;
+    }
+    // Max. time to TX is 65ms
+    if (time_to_tx > 65000) {
+        time_to_tx = 65000;
+    }
+    return rf_mac_setup->fhss_api->read_timestamp(rf_mac_setup->fhss_api) + time_to_tx;
+}
 
 static int8_t mcps_generic_packet_build(protocol_interface_rf_mac_setup_s *rf_ptr, mac_pre_build_frame_t *buffer) {
     phy_device_driver_s *dev_driver = rf_ptr->dev_driver->phy_driver;
@@ -1435,6 +1449,7 @@ static int8_t mcps_generic_packet_build(protocol_interface_rf_mac_setup_s *rf_pt
     tx_buf->len = frame_length;
 
     uint8_t *mhr_start = ptr;
+    buffer->tx_time = mcps_calculate_tx_time(rf_ptr, MAC_TX_PROCESSING_DELAY_INITIAL);
     ptr = mac_generic_packet_write(rf_ptr, ptr, buffer);
 
     if (buffer->fcf_dsn.securityEnabled) {

source/MAC/IEEE802_15_4/mac_mcps_sap.h

@@ -125,6 +125,7 @@ typedef struct mac_pre_build_frame{
     uint8_t *mac_payload;
     uint8_t status;
     uint8_t asynch_channel;
+    uint32_t tx_time;
     bool upper_layer_request;
     bool mac_allocated_payload_ptr:1;
     bool asynch_request:1;

source/MAC/IEEE802_15_4/mac_pd_sap.c

@@ -163,28 +163,19 @@ int8_t mac_pd_sap_req(protocol_interface_rf_mac_setup_s *rf_mac_setup)
 /**
  * Set PHY TX time.
  *
- * \param rf_mac_setup pointer to MAC
- * \param time_to_tx Time from present time to wanted TX time (us)
- * \return 0 if success, -1 when FHSS not registered
+ * \param rf_mac_setup pointer to MAC.
+ * \param tx_time TX timestamp to be set.
  *
  */
-static int mac_pd_sap_set_tx_time(protocol_interface_rf_mac_setup_s *rf_mac_setup, uint16_t time_to_tx)
+static void mac_pd_sap_set_phy_tx_time(protocol_interface_rf_mac_setup_s *rf_mac_setup, uint32_t tx_time)
 {
-    if (rf_mac_setup->fhss_api) {
-        // Max. TX time is 65ms
-        if (time_to_tx > 65000) {
-            time_to_tx = 65000;
-        }
-        uint8_t tx_time_buffer[4];
-        uint32_t tx_time = rf_mac_setup->fhss_api->read_timestamp(rf_mac_setup->fhss_api) + time_to_tx;
-        if (!tx_time) {
-            tx_time++;
-        }
-        common_write_32_bit(tx_time, tx_time_buffer);
-        rf_mac_setup->dev_driver->phy_driver->extension(PHY_EXTENSION_SET_TX_TIME, tx_time_buffer);
-        return 0;
+    // With TX time set to zero, PHY sends immediately
+    if (!tx_time) {
+        tx_time++;
     }
-    return -1;
+    uint8_t tx_time_buffer[4];
+    common_write_32_bit(tx_time, tx_time_buffer);
+    rf_mac_setup->dev_driver->phy_driver->extension(PHY_EXTENSION_SET_TX_TIME, tx_time_buffer);
 }
 
 /**
@@ -194,7 +185,7 @@ static int mac_pd_sap_set_tx_time(protocol_interface_rf_mac_setup_s *rf_mac_setu
  * \return Timestamp of last PHY reception
  *
  */
-static uint32_t mac_pd_sap_get_rx_time(protocol_interface_rf_mac_setup_s *rf_mac_setup)
+static uint32_t mac_pd_sap_get_phy_rx_time(protocol_interface_rf_mac_setup_s *rf_mac_setup)
 {
     uint8_t rx_time_buffer[4];
     rf_mac_setup->dev_driver->phy_driver->extension(PHY_EXTENSION_READ_RX_TIME, rx_time_buffer);
@@ -216,6 +207,7 @@ void mac_pd_sap_state_machine(protocol_interface_rf_mac_setup_s *rf_mac_setup)
                 if (!active_buf) {
                     return;
                 }
+                mac_pd_sap_set_phy_tx_time(rf_mac_setup, active_buf->tx_time);
                 if (active_buf->fcf_dsn.frametype == FC_BEACON_FRAME) {
                     // FHSS synchronization info is written in the end of transmitted (Beacon) buffer
                     dev_driver_tx_buffer_s *tx_buf = &rf_mac_setup->dev_driver_tx_buffer;

source/Service_Libs/fhss/fhss_ws.c

@@ -34,7 +34,7 @@
 // Enable this flag to use channel traces
 #define FHSS_CHANNEL_DEBUG
 
-#define DEF_2E16 16777216
+#define DEF_2E24 0x1000000
 #define IE_HEADER_LENGTH_MASK 0x007f
 #define IE_HEADER_ID_MASK 0x7f80
 #define WH_IE_ID        0x2a
@@ -148,14 +148,13 @@ static uint32_t fhss_ws_calculate_ufsi(fhss_structure_t *fhss_structure, uint32_
     cur_slot--;
     uint32_t remaining_time = (fhss_structure->platform_functions.fhss_get_remaining_slots(fhss_unicast_handler, fhss_structure->fhss_api) / 1000);
     uint32_t time_to_tx = (tx_time - fhss_structure->fhss_api->read_timestamp(fhss_structure->fhss_api)) / 1000;
-    uint32_t ms_since_seq_start = (cur_slot * dwell_time) + (dwell_time-remaining_time) + time_to_tx;
+    uint64_t ms_since_seq_start = (cur_slot * dwell_time) + (dwell_time-remaining_time) + time_to_tx;
     ms_since_seq_start %= (dwell_time*fhss_structure->number_of_channels);
     uint32_t seq_length = 0x10000;
     if (fhss_structure->ws->fhss_configuration.ws_channel_function == WS_TR51CF) {
         seq_length = fhss_structure->number_of_channels;
     }
-
-    return own_floor((float)(ms_since_seq_start * DEF_2E16) / (seq_length*dwell_time));
+    return own_floor((float)(ms_since_seq_start * DEF_2E24) / (seq_length*dwell_time));
 }
 
 static uint16_t fhss_ws_calculate_destination_slot(fhss_structure_t *fhss_structure, uint32_t ufsi, uint32_t ufsi_timestamp, uint8_t dwell_time, uint32_t tx_time)
@@ -164,7 +163,7 @@ static uint16_t fhss_ws_calculate_destination_slot(fhss_structure_t *fhss_struct
     if (fhss_structure->ws->fhss_configuration.ws_channel_function  == WS_TR51CF) {
         seq_length = fhss_structure->number_of_channels;
     }
-    uint32_t dest_ms_since_seq_start = own_ceil((float)(ufsi*seq_length*dwell_time) / DEF_2E16);
+    uint32_t dest_ms_since_seq_start = own_ceil((float)(ufsi*seq_length*dwell_time) / DEF_2E24);
     return (own_floor(((float)((tx_time - ufsi_timestamp)/1000 + dest_ms_since_seq_start) / dwell_time)) % seq_length);
 }