Fixed RU864 Class B ping-slot frequency.

Updated Class B ping-slot handling in order to have different frequency value from beacon.

Author: Daniel Jaeckle

src/mac/LoRaMacClassB.c

@@ -223,63 +223,74 @@ static void ComputePingOffset( uint64_t beaconTime, uint32_t address, uint16_t p
  *
  * \param [IN] channel The channel according to the channel plan.
  *
+ * \param [IN] isBeacon Set to true, if the function shall
+ *                      calculate the frequency for a beacon.
+ *
  * \retval The downlink frequency
  */
-static uint32_t CalcDownlinkFrequency( uint8_t channel )
+static uint32_t CalcDownlinkFrequency( uint8_t channel, bool isBeacon )
 {
     GetPhyParams_t getPhy;
     PhyParam_t phyParam;
-    uint32_t frequency = 0;
-    uint32_t stepwidth = 0;
 
-    getPhy.Attribute = PHY_BEACON_CHANNEL_FREQ;
-    phyParam = RegionGetPhyParam( *Ctx.LoRaMacClassBParams.LoRaMacRegion, &getPhy );
-    frequency = phyParam.Value;
+    getPhy.Attribute = PHY_PING_SLOT_CHANNEL_FREQ;
 
-    getPhy.Attribute = PHY_BEACON_CHANNEL_STEPWIDTH;
+    if( isBeacon == true )
+    {
+        getPhy.Attribute = PHY_BEACON_CHANNEL_FREQ;
+    }
+    getPhy.Channel = channel;
     phyParam = RegionGetPhyParam( *Ctx.LoRaMacClassBParams.LoRaMacRegion, &getPhy );
-    stepwidth = phyParam.Value;
 
-    // Calculate the frequency
-    return frequency + ( channel * stepwidth );
+    return phyParam.Value;
 }
 
 /*!
  * \brief Calculates the downlink channel for the beacon and for
  *        ping slot downlinks.
  *
- * \param [IN] devAddr The address of the device
+ * \param [IN] devAddr The address of the device. Assign 0 if its a beacon.
  *
  * \param [IN] beaconTime The beacon time of the beacon.
  *
- * \param [IN] beaconInterval The beacon interval
+ * \param [IN] beaconInterval The beacon interval.
+ *
+ * \param [IN] isBeacon Set to true, if the function shall
+ *                      calculate the frequency for a beacon.
  *
  * \retval The downlink channel
  */
-static uint32_t CalcDownlinkChannelAndFrequency( uint32_t devAddr, TimerTime_t beaconTime, TimerTime_t beaconInterval )
+static uint32_t CalcDownlinkChannelAndFrequency( uint32_t devAddr, TimerTime_t beaconTime,
+                                                 TimerTime_t beaconInterval, bool isBeacon )
 {
     GetPhyParams_t getPhy;
     PhyParam_t phyParam;
     uint32_t channel = 0;
     uint8_t nbChannels = 0;
-    uint32_t frequency = 0;
 
-    getPhy.Attribute = PHY_BEACON_NB_CHANNELS;
+    // Default initialization - ping slot channels
+    getPhy.Attribute = PHY_PING_SLOT_NB_CHANNELS;
+
+    if( isBeacon == true )
+    {
+        // Beacon channels
+        getPhy.Attribute = PHY_BEACON_NB_CHANNELS;
+    }
     phyParam = RegionGetPhyParam( *Ctx.LoRaMacClassBParams.LoRaMacRegion, &getPhy );
-    nbChannels = (uint8_t) phyParam.Value;
+    nbChannels = ( uint8_t ) phyParam.Value;
 
+    // nbChannels is > 1, when the channel plan requires more than one possible channel
+    // defined by the calculation below.
     if( nbChannels > 1 )
     {
         // Calculate the channel for the next downlink
         channel = devAddr + ( beaconTime / ( beaconInterval / 1000 ) );
         channel = channel % nbChannels;
     }
 
-    // Calculate the frequency for the next downlink
-    frequency = CalcDownlinkFrequency( channel );
-
-    // Calculate the frequency for the next downlink
-    return frequency;
+    // Calculate the frequency for the next downlink. This holds
+    // for beacons and ping slots.
+    return CalcDownlinkFrequency( channel, isBeacon );
 }
 
 /*!
@@ -302,13 +313,13 @@ static void RxBeaconSetup( TimerTime_t rxTime, bool activateDefaultChannel )
     {
         // This is the default frequency in case we don't know when the next
         // beacon will be transmitted. We select channel 0 as default.
-        frequency = CalcDownlinkFrequency( 0 );
+        frequency = CalcDownlinkFrequency( 0, true );
     }
     else
     {
         // This is the frequency according to the channel plan
         frequency = CalcDownlinkChannelAndFrequency( 0, Ctx.BeaconCtx.BeaconTime.Seconds + ( CLASSB_BEACON_INTERVAL / 1000 ),
-                                                     CLASSB_BEACON_INTERVAL );
+                                                     CLASSB_BEACON_INTERVAL, true );
     }
 
     if( Ctx.NvmCtx->BeaconCtx.Ctrl.CustomFreq == 1 )
@@ -321,7 +332,7 @@ static void RxBeaconSetup( TimerTime_t rxTime, bool activateDefaultChannel )
     {
         // Set the frequency which was provided by BeaconTimingAns MAC command
         Ctx.BeaconCtx.Ctrl.BeaconChannelSet = 0;
-        frequency = CalcDownlinkFrequency( Ctx.BeaconCtx.BeaconTimingChannel );
+        frequency = CalcDownlinkFrequency( Ctx.BeaconCtx.BeaconTimingChannel, true );
     }
 
     if( ( Ctx.BeaconCtx.Ctrl.BeaconAcquired == 1 ) || ( Ctx.BeaconCtx.Ctrl.AcquisitionPending == 1 ) )
@@ -1021,7 +1032,8 @@ static void LoRaMacClassBProcessPingSlot( void )
             if( Ctx.NvmCtx->PingSlotCtx.Ctrl.CustomFreq == 0 )
             {
                 // Restore floor plan
-                frequency = CalcDownlinkChannelAndFrequency( *Ctx.LoRaMacClassBParams.LoRaMacDevAddr, Ctx.BeaconCtx.BeaconTime.Seconds, CLASSB_BEACON_INTERVAL );
+                frequency = CalcDownlinkChannelAndFrequency( *Ctx.LoRaMacClassBParams.LoRaMacDevAddr, Ctx.BeaconCtx.BeaconTime.Seconds,
+                                                             CLASSB_BEACON_INTERVAL, false );
             }
 
             // Open the ping slot window only, if there is no multicast ping slot
@@ -1178,7 +1190,8 @@ static void LoRaMacClassBProcessMulticastSlot( void )
             if( frequency == 0 )
             {
                 // Restore floor plan
-                frequency = CalcDownlinkChannelAndFrequency( Ctx.PingSlotCtx.NextMulticastChannel->ChannelParams.Address, Ctx.BeaconCtx.BeaconTime.Seconds, CLASSB_BEACON_INTERVAL );
+                frequency = CalcDownlinkChannelAndFrequency( Ctx.PingSlotCtx.NextMulticastChannel->ChannelParams.Address,
+                                                             Ctx.BeaconCtx.BeaconTime.Seconds, CLASSB_BEACON_INTERVAL, false );
             }
 
             Ctx.MulticastSlotState = PINGSLOT_STATE_RX;

src/mac/region/Region.h

@@ -808,10 +808,18 @@ typedef enum ePhyAttribute
      * The number of channels for the beacon reception.
      */
     PHY_BEACON_NB_CHANNELS,
+    /*!
+     * Ping slot channel frequency.
+     */
+    PHY_PING_SLOT_CHANNEL_FREQ,
     /*!
      * The datarate of a ping slot channel.
      */
     PHY_PING_SLOT_CHANNEL_DR,
+    /*
+     * The number of channels for the ping slot reception.
+     */
+    PHY_PING_SLOT_NB_CHANNELS,
     /*!
      * The equivalent spreading factor value from datarate
      */
@@ -933,6 +941,12 @@ typedef struct sGetPhyParams
      * PHY_MIN_RX_DR, PHY_MAX_PAYLOAD.
      */
     uint8_t DownlinkDwellTime;
+    /*!
+     * Specification of the downlink channel. Used in Class B only.
+     * The parameter is needed for the following queries:
+     * PHY_BEACON_CHANNEL_FREQ, PHY_PING_SLOT_CHANNEL_FREQ
+     */
+    uint8_t Channel;
 }GetPhyParams_t;
 
 /*!

src/mac/region/RegionAS923.c

@@ -327,6 +327,11 @@ PhyParam_t RegionAS923GetPhyParam( GetPhyParams_t* getPhy )
             phyParam.Value = AS923_BEACON_CHANNEL_DR;
             break;
         }
+        case PHY_PING_SLOT_CHANNEL_FREQ:
+        {
+            phyParam.Value = AS923_PING_SLOT_CHANNEL_FREQ;
+            break;
+        }
         case PHY_PING_SLOT_CHANNEL_DR:
         {
             phyParam.Value = AS923_PING_SLOT_CHANNEL_DR;
@@ -335,6 +340,7 @@ PhyParam_t RegionAS923GetPhyParam( GetPhyParams_t* getPhy )
         case PHY_SF_FROM_DR:
         {
             phyParam.Value = DataratesAS923[getPhy->Datarate];
+            break;
         }
         default:
         {

src/mac/region/RegionAS923.h

@@ -217,6 +217,11 @@ extern "C"
  */
 #define AS923_BEACON_CHANNEL_FREQ                   923400000
 
+/*!
+ * Ping slot channel frequency
+ */
+#define AS923_PING_SLOT_CHANNEL_FREQ                923400000
+
 /*!
  * Payload size of a beacon frame
  */

src/mac/region/RegionAU915.c

@@ -324,7 +324,7 @@ PhyParam_t RegionAU915GetPhyParam( GetPhyParams_t* getPhy )
         }
         case PHY_BEACON_CHANNEL_FREQ:
         {
-            phyParam.Value = AU915_BEACON_CHANNEL_FREQ;
+            phyParam.Value = AU915_BEACON_CHANNEL_FREQ + ( getPhy->Channel * AU915_BEACON_CHANNEL_STEPWIDTH );
             break;
         }
         case PHY_BEACON_FORMAT:
@@ -349,6 +349,11 @@ PhyParam_t RegionAU915GetPhyParam( GetPhyParams_t* getPhy )
             phyParam.Value = AU915_BEACON_NB_CHANNELS;
             break;
         }
+        case PHY_PING_SLOT_CHANNEL_FREQ:
+        {
+            phyParam.Value = AU915_PING_SLOT_CHANNEL_FREQ + ( getPhy->Channel * AU915_BEACON_CHANNEL_STEPWIDTH );
+            break;
+        }
         case PHY_PING_SLOT_CHANNEL_DR:
         {
             phyParam.Value = AU915_PING_SLOT_CHANNEL_DR;
@@ -357,6 +362,7 @@ PhyParam_t RegionAU915GetPhyParam( GetPhyParams_t* getPhy )
         case PHY_SF_FROM_DR:
         {
             phyParam.Value = DataratesAU915[getPhy->Datarate];
+            break;
         }
         default:
         {

src/mac/region/RegionAU915.h

@@ -208,6 +208,11 @@ extern "C"
  */
 #define AU915_BEACON_CHANNEL_STEPWIDTH              600000
 
+/*!
+ * Ping slot channel frequency
+ */
+#define AU915_PING_SLOT_CHANNEL_FREQ                923300000
+
 /*!
  * Number of possible beacon channels
  */

src/mac/region/RegionCN470.c

@@ -278,6 +278,11 @@ PhyParam_t RegionCN470GetPhyParam( GetPhyParams_t* getPhy )
             phyParam.fValue = CN470_DEFAULT_ANTENNA_GAIN;
             break;
         }
+        case PHY_BEACON_CHANNEL_FREQ:
+        {
+            phyParam.Value = CN470_BEACON_CHANNEL_FREQ;
+            break;
+        }
         case PHY_BEACON_FORMAT:
         {
             phyParam.BeaconFormat.BeaconSize = CN470_BEACON_SIZE;
@@ -300,6 +305,11 @@ PhyParam_t RegionCN470GetPhyParam( GetPhyParams_t* getPhy )
             phyParam.Value = CN470_BEACON_NB_CHANNELS;
             break;
         }
+        case PHY_PING_SLOT_CHANNEL_FREQ:
+        {
+            phyParam.Value = CN470_PING_SLOT_CHANNEL_FREQ;
+            break;
+        }
         case PHY_PING_SLOT_CHANNEL_DR:
         {
             phyParam.Value = CN470_PING_SLOT_CHANNEL_DR;
@@ -308,6 +318,7 @@ PhyParam_t RegionCN470GetPhyParam( GetPhyParams_t* getPhy )
         case PHY_SF_FROM_DR:
         {
             phyParam.Value = DataratesCN470[getPhy->Datarate];
+            break;
         }
         default:
         {

src/mac/region/RegionCN470.h

@@ -192,6 +192,11 @@ extern "C"
  */
 #define CN470_BEACON_CHANNEL_STEPWIDTH              200000
 
+/*!
+ * Ping slot channel frequency
+ */
+#define CN470_PING_SLOT_CHANNEL_FREQ                508300000
+
 /*!
  * Number of possible beacon channels
  */

src/mac/region/RegionCN779.c

@@ -295,6 +295,11 @@ PhyParam_t RegionCN779GetPhyParam( GetPhyParams_t* getPhy )
             phyParam.Value = CN779_BEACON_CHANNEL_DR;
             break;
         }
+        case PHY_PING_SLOT_CHANNEL_FREQ:
+        {
+            phyParam.Value = CN779_PING_SLOT_CHANNEL_FREQ;
+            break;
+        }
         case PHY_PING_SLOT_CHANNEL_DR:
         {
             phyParam.Value = CN779_PING_SLOT_CHANNEL_DR;
@@ -303,6 +308,7 @@ PhyParam_t RegionCN779GetPhyParam( GetPhyParams_t* getPhy )
         case PHY_SF_FROM_DR:
         {
             phyParam.Value = DataratesCN779[getPhy->Datarate];
+            break;
         }
         default:
         {

src/mac/region/RegionCN779.h

@@ -204,6 +204,11 @@ extern "C"
  */
 #define CN779_BEACON_CHANNEL_FREQ                   785000000
 
+/*!
+ * Ping slot channel frequency
+ */
+#define CN779_PING_SLOT_CHANNEL_FREQ                785000000
+
 /*!
  * Payload size of a beacon frame
  */