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sh123 / esp32_loradv

ESP32 based Codec2/OPUS DV handheld trasceiver
GNU General Public License v2.0
34 stars 6 forks source link

add Reliable Packets for voice packet #7

Closed jumbo5566 closed 1 year ago

jumbo5566 commented 1 year ago

hi,friend, i 'm testing digital voice,and digital photo for lora i 'm try to add Reliable-Packets for loradv,then we can sent digital packet in Reliable mode,this can increat distance and voice quality. https://stuartsprojects.github.io/2021/08/25/Reliable-Packets-Part1.html

sh123 commented 1 year ago

not sure that acknowledging each voice packet is good idea for the same reasons why RTP over UDP is commonly used in Internet

arodland commented 1 year ago

Yeah, adding ARQ to a realtime stream like voice makes things worse, not better.

LoRa already has FEC, and the default config for esp32_loradv already uses a rate 4/7 code, which is close to the maximum. If the packet doesn't get through even with that, it doesn't make sense to retransmit — you probably don't have time for a retransmission before the next voice packet needs to go out. If you do have time for a retransmission, then you could equally well go one SF step higher, putting twice as much energy into each bit, and get more range that way.

Also, using reliable mode totally breaks the usecase where there is one transmitter and multiple receivers, which is very common for simplex voice.