Author Topic: Optimizing for jitter and packet loss on 4G/LTE  (Read 13217 times)


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Optimizing for jitter and packet loss on 4G/LTE
« on: 2015-06-07, 14:54:14 »
I am using with 4G/LTE at the radio site. I have everything working: SSB/CW. There were IP address issues getting the provide to give me a permanent and accessible IP address from the public. And, errors made by the provider I've lost access to my address and had to work with the ISP again.

The last problem I am chasing is jitter. This is happening on all my VoIP applications, included.

Has anyone dealt with this problem and willing to share their experiences? If this can be addressed with tuning parameters on, or do I need to request changes by the ISP?




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Re: Optimizing for jitter and packet loss on 4G/LTE
« Reply #1 on: 2015-06-08, 12:23:46 »
In the RRC you can increase jtter buffer size and delay. Try to use larger RTP package, test with 40ms. Lower audio quality = 0 can be a solution. That's about what you can do locally in the RRCs

73 de mike


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Re: Optimizing for jitter and packet loss on 4G/LTE
« Reply #2 on: 2015-06-08, 12:23:53 »

This is my 3G/4G checklist which may help you:

3G Checklist
Try reducing your bandwidth to a minimum and changing some parameters to compensate
for a poor line. Here are some tips:

1) These are important:
- audio quality to 0 (half the bandwidth of codec 2 and more than adequate for SSB & CW)
- turn continuous RTP on or set RTP to continuous (depending upon firmware version)
- If using the K3 Twin or Yaesu with a second receiver, then turn off "audio dual-rx" on the
   radio RRC under the radio settings. This doubles the necessary bandwidth if on.

2) Play around with these 3 until you are satisfied:
- increase rx jitter buffer to min 12+
- increase rx jitter delay to min 10+
- audio packet size 20 or 40

3) Also, make sure that serial ports COM1 and COM2 are turned off if not used,
or that either being used is set to the minimum bps necessary to handle the serial
communication. For example, use 4800 for CAT on a rig like the TS-480 and not
a high speed like 57600, since the higher speed is completely unnecessary.

Mitch DJ0QN