Reduce the default channel list

matthijskooijman · matthijskooijman · commit 03ec06b3d03c · 2016-02-20T12:24:04.000+01:00
By default, LMIC uses 6 standard channels for joining and 3 standard
channels for normal operation which are defined in the LoRaWAN
specification. On top of that, it defines 3 additional channels.

However, in practice it turns out that 3 of the 6 joining channels are
not actually used by gateway, and neither are the 3 additional channels
for normal operation. To maximize default operability, this commit
reduces the default channels list to just (the same) 3 channels for both
joining and normal operation (but at different duty cycles).

Extra channels  can be configured from the sketch, using
LMIC_setupChannel(), and the example sketches will be modifed according
to this.
diff --git a/src/lmic/lmic.c b/src/lmic/lmic.c
@@ -526,32 +526,25 @@ void LMIC_setPingable (u1_t intvExp) {
 //
 // BEG: EU868 related stuff
 //
-enum { NUM_DEFAULT_CHANNELS=6 };
-static CONST_TABLE(u4_t, iniChannelFreq)[12] = {
+enum { NUM_DEFAULT_CHANNELS=3 };
+static CONST_TABLE(u4_t, iniChannelFreq)[6] = {
     // Join frequencies and duty cycle limit (0.1%)
-    EU868_F1|BAND_MILLI, EU868_J4|BAND_MILLI,
-    EU868_F2|BAND_MILLI, EU868_J5|BAND_MILLI,
-    EU868_F3|BAND_MILLI, EU868_J6|BAND_MILLI,
+    EU868_F1|BAND_MILLI, EU868_F2|BAND_MILLI, EU868_F3|BAND_MILLI,
     // Default operational frequencies
     EU868_F1|BAND_CENTI, EU868_F2|BAND_CENTI, EU868_F3|BAND_CENTI,
-    EU868_F4|BAND_MILLI, EU868_F5|BAND_MILLI, EU868_F6|BAND_DECI
 };
 
 static void initDefaultChannels (bit_t join) {
     os_clearMem(&LMIC.channelFreq, sizeof(LMIC.channelFreq));
     os_clearMem(&LMIC.channelDrMap, sizeof(LMIC.channelDrMap));
     os_clearMem(&LMIC.bands, sizeof(LMIC.bands));
 
-    LMIC.channelMap = 0x3F;
-    u1_t su = join ? 0 : 6;
-    for( u1_t fu=0; fu<6; fu++,su++ ) {
+    LMIC.channelMap = 0x07;
+    u1_t su = join ? 0 : 3;
+    for( u1_t fu=0; fu<3; fu++,su++ ) {
         LMIC.channelFreq[fu]  = TABLE_GET_U4(iniChannelFreq, su);
         LMIC.channelDrMap[fu] = DR_RANGE_MAP(DR_SF12,DR_SF7);
     }
-    if( !join ) {
-        LMIC.channelDrMap[5] = DR_RANGE_MAP(DR_SF12,DR_SF7);
-        LMIC.channelDrMap[1] = DR_RANGE_MAP(DR_SF12,DR_FSK);
-    }
 
     LMIC.bands[BAND_MILLI].txcap    = 1000;  // 0.1%
     LMIC.bands[BAND_MILLI].txpow    = 14;
