62 lines
2.1 KiB
Markdown
62 lines
2.1 KiB
Markdown
LoRa Time on Air calculator
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===========================
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A calculator of the time on air of LoRa PHY frame in Python.
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This script refers to the section 4.1.1.6. LoRa Packet Structure,
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[SX1276/77/78/79 Datasheet][http://www.semtech.com/images/datasheet/sx1276_77_78_79.pdf].
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The default value is aligned to LoRaWAN AS923.
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## Usage
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lorawan_toa.py [-h] [--band-width N_BW] [--disable-dro] [--disable-eh]
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[--cr N_CR] [--preamble N_PREAMBLE] [-v] [-d]
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SF SIZE
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positional arguments:
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SF Spreading Factor. It should be from 7 to 12.
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SIZE PHY payload size in byte. It's equal to the MAC
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payload + 5.
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optional arguments:
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-h, --help show this help message and exit
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--band-width N_BW bandwidth in kHz. default is 125 kHz.
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--disable-dro disable the low data rate optimization. default is
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enable as LoRaWAN does.
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--disable-eh disable the explicit header. default is enable as
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LoRaWAN does.
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--cr N_CR specify the CR value. default is 1 as LoRaWAN does.
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--preamble N_PREAMBLE
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specify the preamble. default is 8 for AS923.
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-v enable verbose mode.
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-d increase debug mode.
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## Examples
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with the -v option, it shows the ToA as well as the related information.
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% python lorawan_toa.py 12 64 -v
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PHY payload size : 64 Bytes
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MAC payload size : 59 Bytes
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Spreading Factor : 12
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Band width : 125 kHz
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Low data rate opt. : enable
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Explicit header : enable
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CR (coding rate) : 1 (4/5)
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Preamble size : 8 symbols
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Time on Air : 2793.472 msec
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MAC frame data rate : 63.998 bps
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without the -v option, it simply shows the ToA.
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% python lorawan_toa.py --band-width=500 7 128
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71.744
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## graph_as923.py
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It makes a set of figures about Time on Air and PHYPayload size,
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especially LoRaWAN AS923 using matlib like below.
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