Diff: AlohaTransceiver.cpp

Revision:

24:8f31c33c7675

Parent:

23:4b51a8e27f6a

Child:

25:bcd1cee4e5a8

--- a/AlohaTransceiver.cpp	Fri Sep 02 04:20:26 2016 +0000
+++ b/AlohaTransceiver.cpp	Fri Sep 02 04:43:42 2016 +0000
@@ -243,35 +243,51 @@
     }
 }
 
-bool send(BasicPacket *packet)
-{
-    return true;
-}
-
-bool AlohaTransceiver::send(uint8_t *payload, uint8_t payload_length, uint8_t dest_addr)
-{
-    // assume the user will not transmit payload longer than 16 bytes
-    if (payload_length > 16)
-    {
-        return false;
-    }
+bool AlohaTransceiver::send(BasicPacket *packet)
+{   
+    // for the reason that we only transmit basic packet format, the 
+    // length is always 8
+    uint8_t payload_length = 8;
+    
+    // get destination address
+    uint8_t destination_address = findNextHop(packet->getDestinationID());
+    
+    // serialize the packet from upper layer
+    uint8_t buffer[payload_length];
+    memset(buffer, 0x0, sizeof(buffer));
+    
+    // copy bytes into buffer
+    packet->serialize(buffer);
     
     // create a new frame
     AlohaFrame *frame = new AlohaFrame();
     
     // set properfies
+    // set payload as data
     frame->setType(AlohaFrame::Aloha_Data);
+    
+    // set payload length (8 bytes for BasicPacket)
     frame->setPayloadLength(payload_length);
+    
+    // set mac layer device id
     frame->setSourceAddress(deviceId);
-    frame->setDestinationAddress(dest_addr & 0x0f);
+    
+    // set mac layer destination id
+    // for multiple hop system, the destination is the next hop
+    // in this case, we use destination id from upper layer
+    frame->setDestinationAddress(packet->getDestinationID());
+    
+    // set full message flag (always true in this case)
     frame->setFullMessageFlag(0x1);
-    frame->setSequenceID(seqid[dest_addr]++);    // use dest_addr as key for accessing sequence id
-                                                // the seqid should increase as it successfully transmit the packet
     
+    // use dest_addr as key for accessing sequence id
+    // the seqid should increase as it successfully transmit the packet
+    frame->setSequenceID(seqid[destination_address]++);    
+                                                
     // set payload
     for (uint8_t i = 0; i < payload_length; i++)
     {
-        frame->setPayload(i, payload[i]);
+        frame->setPayload(i, buffer[i]);
     }
     
     // calculate crc
@@ -279,7 +295,7 @@
     
     // push frame to the back of queue
     AlohaTxQueue.enqueue(frame);
-
+                         
     return true;
 }
 
@@ -313,6 +329,12 @@
     deviceId = id;
 }
 
+uint8_t AlohaTransceiver::findNextHop(uint8_t addr)
+{
+    // TODO: maintain a routing lookup table for choosing shortest path
+    return addr;
+}
+
 #if USE_MODEM_LORA == 1
 AlohaTransceiver::LoRaSettings_t *AlohaTransceiver::getSettings()
 {
@@ -385,3 +407,4 @@
     debug( "> OnRxError\n\r" );
 #endif
 }
+