rpp0
commented
6 years ago The problem is implicit header mode: it is implemented differently for different chipset vendors based on my findings. That is, some vendors include a custom header to pass the length anyway, others don't.
In your case, it seems the transmitter is using reduced rate mode. I have a branch that might work for the sx1272 in implicit mode, but it requires some cleanups before I will push it. For now, I advise to use expicit header mode, which should work in all cases.
On Wed, Nov 1, 2017, 22:35 habbasi3 notifications@github.com wrote:
Hi, I am sending 1 LoRa packet (1,2, or 3 bytes long) every second at 915 MHz (125 kHz bw) from a SX1272 LoRa end-node using the program https://os.mbed.com/users/dudmuck/code/sx127x_simple_TX_shield/. Using another SX1272 end-node as a receiver, I am able to receive and decode the message just fine. However, with my USRP B210 device using gr-lora as a receiver, I am not getting the correctly decoded payload. The payload being printed is incorrect and has incorrect number of bytes. I have tried various SF, and code rates, but it still doesn't work. Only under 1 specific scenario, I see the packet payload being printed out partially correctly, but only after 7 incorrectly decoded packets.
I am using 3 bytes payload (AA,CC,88). The following is my configuration in gr-lora: code rate: 4/8, SF 7, BW 125kHz, freq: 915MHz, internal sampling rate (1Msps), implicit header, and CRC (True).
After sending 18 packets (in 18 seconds), only 3 packets were partially correct as shown below. one packet gets decoded after 7 incorrectly decoded packets. ff 88 f2 aa cc 88 fd c1 e2 c3 6d 5f d7 da e1 61 42 73 a3 65 f1 f9 e4 46 9b be 30 b6 d0 c1 ce fd 92 8a f2 7d 08 62 0f cd 27 31 b4 66 df f8 2f 32 58 4a 85 2a ff 88 f2 aa cc 88 fd c1 e2 c3 6d 5f d7 da e1 61 42 73 a3 65 f1 f9 e4 46 9b be 30 b6 d0 c1 ce fd 92 8a f2 7d 08 62 0f cd 27 31 b4 66 df f8 2f 32 58 4a 85 2a ff 88 f2 aa cc 88 fd c1 e2 c3
I tried every possible configuration combination but only this seemed to work partially. At sender, I am using coding rate: 0 (I have tried 1-8 but they don't work). Please let me know what am I missing. Thanks for your help.
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habbasi3
Hi, I am sending 1 LoRa packet (1,2, or 3 bytes long) every second at 915 MHz (125 kHz bw) from a SX1272 LoRa end-node using the program https://os.mbed.com/users/dudmuck/code/sx127x_simple_TX_shield/. Using another SX1272 end-node as a receiver, I am able to receive and decode the message just fine. However, with my USRP B210 device using gr-lora as a receiver, I am not getting the correctly decoded payload. The payload being printed is incorrect and has incorrect number of bytes. I have tried various SF, and code rates, but it still doesn't work.
Only under 1 specific scenario, I see the packet payload being printed out partially correctly, but only after 7 incorrectly decoded packets. This is the partially working configuration in gr-lora: code rate: 4/8, SF 7, BW 125kHz, freq: 915MHz, internal sampling rate (1Msps), implicit header, and CRC (True). I am using 3 bytes payload (AA,CC,88).
After sending 18 packets (in 18 seconds), only 3 packets were partially correct as shown below. one packet gets decoded after 7 incorrectly decoded packets. ff 88 f2 aa cc 88 fd c1 e2 c3 6d 5f d7 da e1 61 42 73 a3 65 f1 f9 e4 46 9b be 30 b6 d0 c1 ce fd 92 8a f2 7d 08 62 0f cd 27 31 b4 66 df f8 2f 32 58 4a 85 2a ff 88 f2 aa cc 88 fd c1 e2 c3 6d 5f d7 da e1 61 42 73 a3 65 f1 f9 e4 46 9b be 30 b6 d0 c1 ce fd 92 8a f2 7d 08 62 0f cd 27 31 b4 66 df f8 2f 32 58 4a 85 2a ff 88 f2 aa cc 88 fd c1 e2 c3
I tried every possible configuration combination but only this seemed to work partially. At sender, I am using coding rate: 0 (I have tried 1-8 but they don't work). More than 3 bytes long payload, even this configuration doesn't work. Please let me know what am I missing. Thanks for your help.