Added noise floor monitoring and reporting to host

Config.h

@@ -95,6 +95,7 @@
 	#define CSMA_CW_PER_BAND_WINDOWS   15
 	#define CSMA_BAND_1_MAX_AIRTIME    7
 	#define CSMA_BAND_N_MIN_AIRTIME    85
+	#define CSMA_INFR_THRESHOLD_DB     12
 	int csma_slot_ms                =  CSMA_SLOT_MIN_MS;
 	unsigned long difs_ms           =  CSMA_SIFS_MS + 2*csma_slot_ms;
 	unsigned long difs_wait_start   = -1;
@@ -131,6 +132,8 @@
 	uint8_t model     = 0x00;
 	uint8_t hwrev     = 0x00;
 
+	#define NOISE_FLOOR_SAMPLES 16
+	int     noise_floor     = -292;
     int     current_rssi    = -292;
 	int		last_rssi		= -292;
 	uint8_t last_rssi_raw   = 0x00;