VOIP over 3G – Update 2

OK, so I have been living with VOIP over 3G for a little while now. It is working fine providing you have a good 3G connection. How you know you have a good 3G connection is a mystery to me but I guess the signal strength is a factor. The service provided by Exetel is very good and the price – well it almost unbeatable.

The calls I have made have almsot all been very clear with just a little bit of garble now and then. Last week I had an 8 min phone conversation and the call was very acceptable, especially given the whole thing cost me on my calulation about 50c (data of 2MB per min and VSP cost of 10c).

I think the major issue still is the fact that SIPdroid only supports the G711 codec. With luck the recent bounty proposed on SIPdroids site for the development of low bandwidth codecs (lets hope G729) will help make this an even better experience (an even cheaper).

2 Replies to “VOIP over 3G – Update 2”

  1. I have just got myself an android phone with sipdroid and an exetel hspa sim + VOIP acount.

    Was wondering if you are using pbxes with exetel voip or have just been accessing the exetel sip server directly.

    1. Hi Tony.

      Actually I nave never used Exetels VOIP sevice. I used pennytel as a trunk on pbxes and registered sipdroid to pbxes. I used pbxes without any problems except for perhaps a little bit of delay caused by the long distance data packets need to travel (Australia to Japan and back).

      Recentley I have been able to register sipdroid to my Asterisk box and have been trialling it. It kind of cool being a mobiel extension of you own Asterisk box. It work OK but to be honest, it is not the massive improvement I was expecting. Despite me using my local Asterisk box there seems to be a few seconds between when the person I called picks up and when I actually start hearing what they say – I believe I am loosing the frist few seconds (5s-10s) of the conversation. Using my Asterisk box there are all sorts of factors that are likely to affect performance now, that said, I don’t have these same problems when I use a remote extension that is hard wired so I assume a large proportion is 3G latency/performance.

      Lastly, I think a lot of the performace issues can be reduced by redusing the massive amounts of data sipdroid currently needs to transmit voice, G711 uses 80kbps up and down, this is compared to G729 which uses less than 10kbps. If the G729 codec could be implimented for sipdroid/android we would be laughing.

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