updated

README.md

@@ -1,5 +1,5 @@
-lorawan_toa
+LoRa Time on Air calculator
-===========
+===========================
 
 A calculator of the time on air of LoRa PHY frame in Python.
 This script refers to the section 4.1.1.6. LoRa Packet Structure,
@@ -7,13 +7,43 @@ This script refers to the section 4.1.1.6. LoRa Packet Structure,
 
 ## Usage
 
-    Usage: lorawan_toa.py (sf) (size) [bw] [de]
+    lorawan_toa.py [-h] [--band-width N_BW] [--disable-dro] [--disable-eh]
-        size: PHY Payload siz (= MAC Payload + 5)
+                          [--cr N_CR] [--preamble N_PREAMBLE] [-v] [-d]
-        bw: bandwidth. default is 125 kHz.
+                          SF SIZE
-        de: low data optimization. default is 0.
     
-    % python lorawan_toa.py 12 64 500
+    positional arguments:
-    616.448 (ms)
+      SF                    Spreading Factor. It should be from 7 to 12.
+      SIZE                  PHY payload size in byte. It's equal to the MAC
+                            payload + 5.
+    
+    optional arguments:
+      -h, --help            show this help message and exit
+      --band-width N_BW     bandwidth in kHz. default is 125 kHz.
+      --disable-dro         disable the low data rate optimization. default is
+                            enable as LoRaWAN does.
+      --disable-eh          disable the explicit header. default is enable as
+                            LoRaWAN does.
+      --cr N_CR             specify the CR value. default is 1 as LoRaWAN does.
+      --preamble N_PREAMBLE
+                            specify the preamble. default is 8 for AS923.
+      -v                    enable verbose mode.
+      -d                    increase debug mode.
+
+## Examples
+
+    % python lorawan_toa.py -v 12 64
+    PHY payload size  : 64 Bytes
+    MAC payload size  : 59 Bytes
+    Spreading Factor  : 12
+    Band width        : 125 kHz
+    Low data rate opt.: enable
+    Explicit header   : enable
+    CR (coding rate)  : 1 (4/5)
+    Preamble size     : 8 symbols
+    Time on Air       : 2793.472 msec
+
+    % python lorawan_toa.py --band-width=500 7 128    
+    71.744
 
 ## graph_as923.py