Hello Nokia Experts,
I hope that this is the correct place to ask the following questions. If not, I will place in the VoIP area.
Anyway, my questions relates to the different performance capabilities of Nokia handsets with respect to the quality of 3G packet data (IP) service.
For 5 months I have been testing the quality of VoIP via 3G/UMTS on a Nokia N95 8GB. I have found that over this time the quality of voice calls via the VoIP client on the N95 8GB to be good to very good. In fact we have found it to be comparable to a normal circuit switched call. The used codec was G729a with a 40 msec payload cycle.
I then decided to carry out the same test with a E51 handset.
Using the same procedure as with the N95, it was found that the voice quality was no where as good. In fact, I found that as I walked around the office I could cause the speech to break up at more or less the same location every time. It is highly repeatable. On both handsets the signal strength display was full strength.
To carry out some further testing, I then connected, via the usb cable, a laptop pc running a SIP softphone. I then carried out similar tests. That is, make a voice call via the laptop and walk around the office. ! The results, however, were the same. N95 was perfect and E51 breaking up in the same locations.
So, my questions to the Nokia experts are, should the 3G packet data capabilities of these two phones be the same? Are the handsets working as designed or is it an issue?
It is my feeling that the E51 does not handle reflections as well as the N95. Also, from the testing I have done, with the correct handset (N95 8GB) doing VoIP on 3G (In Australia on Telstra's Next G network) can be done, and to an acceptable voice quality.
BTW, I will be testing a Nokia 6120 after I find a suitable VoIP client to load.