AS923
923Mhz
900Mhz
KR920
920Mhz
900Mhz
US915
915Mhz
900Mhz
Bandwidth:
there are 3 options for bandwidth setting
-
125 Khz, 250 Khz, 500 Khz.
Spreading Factor:
there are 8 options for Spreading Factor setting – SF5, SF6, SF7, SF8,
SF9, SF10, SF11, SF12.
The effective amount of LoRa transmission data is related to the spreading factor and
bandwidth. In the following reference table 5.4
-
2, it shows the amount of bitrate is
decrease with Spreading Factor based on 125 khz bandwidth. It is trade off with
Spreading Factor and bandwidth. With the higher Spreading Factor, the transmission will
get better Signal Noise Ratio to ensure the transmission quality, but got lower bitrate,
higher distance and slower transmit time.
Here is the trade
-
off concept of LoRa:
Lower the Spreading Factor
-
> Higher the Data Rate.
-
> Less Range
Higher the Spreading Factor
-
> Less the Data Rate –>Higher the over
-
the
-
air time.
-
>
More range
Spreading Factor
Chips/Symbol
SNR Limit
Time
-
on
-
air
(10Bytes Packet)
Bitrate
7
128
-
7.5
56ms
5469 bps
8
256
-
10
103ms
3125 bps
9
512
-
12.5
205ms
1758 bps
10
1024
-
15
371ms
977 bps
11
2048
-
17.5
741ms
537 bps
12
4096
-
20
1483ms
293 bps
Code Rate:
supports 4 options 4/5, 4/6, 4/7, 4/8.
Tx(RF) Power
: Transmit power setting. The maximum transmit power up to 22dBm.
Table 5.4
-
1
Table 5.4
-
2 Based on 125 Khz Bandwidth
