HSDPA/3G automatic switching

[cablefreak]

Hello,

I have just upgraded to the official GPS ROM and I am on the Swedish 3 operator. I have noticed since the upgrade that the network connection is switching from 3G to HSDPA when there is a demand of bandwidth or simply when there is data in either direction.

I can see that the purpose of this was to make it possible and more reliable to place and receive calls during data sessions. I have figured out though, that with the old ROM, there was no such switching (but there was no distinction with the icon, so you really had no idea) and the connection speed was always constantly 1Mbits/s when using Internet Sharing for example. Now with the HSDPA/3G switching/throttling, the connection often drops down to 3G speeds and Skype-calls are lacking quality from this a bit when using Skype in the car which i do quite regularly nowadays using my Jabra JX-10 headset.

I also realize that there is still a problem with outgoing and incoming calls during these automaticly switched-on HSDPA-sessions. That is probably why HTC has decided to keep the HSDPA sessions as short as possible, that's fine, but what boggles me is the algorithm used for the switching. It seems to always kick in HSDPA in the beginning of a new data session, and after a short time of inactivity (while pondering what favourite page to open this time) the connection drops down to 3G and it won't kick back to HSDPA even when you start browsing again, until a certain period of "non-HSDPA-ratio" has been reached and the phone thinks it would be OK to kick in the highspeed again for a little while.

I also noticed that using Skype would keep HSDPA alive once you place a call from a fresh started data session and keep talking ;-)

This is not a particular problem to me, I was just wondering of anyone else here has noticed and had an idea of what the programmers had in mind?

BTW: I am running TomTom 6.010 and Franson GpsGate on the machine now and it works absolutely like a dream. I used to have a Blue-I Bluetooth GPS in the car (Trimble based chipset, only 8 channels but quite OK piece of hardware) but this is far superior when it comes to HOLDING a persistent fix also when moving indoors. The TTFF is quite fast as long as you are outdoors, most of the time i have a fix before i leave the parking space. I noticed there being a dynamic number of satellites of the receiver, sometimes i see 7 out of 8 satellites, and then sometimes i see 10 out of 12! Anyone noticed?

Thanks in advance! Cheers...

[inmaket]

It’s not your phone that decide to change from HSDPA mode to normal R99 (384kbits) mode and vice versa. Everything are always controlled by the network. The behaviors that you describe are normal. Besides the HSDPA is quit new for the operators and new parameters needs to be tuned for best performance for every users.
BTW, the degradation that you notice. You are not alone that use HSDPA.... :D Its finally the big success for 3G :rolleyes:

[Baxter]

I use Phone Alarm profiles and BandSwitch to control my connection based on business hours. I get a poor singal unless on 3G where my office is located. I force it to GPRS otherwise to save battery.

[Shrooma]

I have similar problems, cannot receive or start calls when HSDPA connected. Shouldn't that be possible anyway, calling and transferring data at the same time? Or is this a network provider problem?

[Quist]

I too am on the Swedish operator 3. I have an unlocked, non-operator distributed HTC TyTN that I had updated the radio to 1.40xxx and the ROM to Black Dymond 3.5 and was having the exact same problem. I could reproduce the incoming call not getting through error every single time I got the phone to go into HSDPA mode.

After some initial searching I read somewhere it was network dependent (Nokia switches vs Ericsson) and the only way to solve it was to disable the HSDPA using e.g. HTweakC, which I did and it solved the problem, but then of course I couldn't take advantage of the high-speed data access, which was the major reason I got this phone.

I recently noticed that 3 released a new extended ROM with instructions to update the ROM to the latest (as is available on the ftp here) then install their ExtROM. I went to the trouble to try and breakdown what was in this extended ROM, but being a newbie to pocketpc it was all hyroglyphics to me, so I went ahead and installed it over my old HTC ext ROM (which I saved for later use just in case).

When I get around to it I may mount this extended ROM here (I have it, but don't have too much time to put it up right now, so someone may beat me to it).

Anyway, Black Dymond 3.5 didn't install the Extended ROM after a hard reset (assuming that was the intention), so I did it myself afterwards. One initial bug that showed up quickly was the Comm Manager not wanting to start saying it would only manage a max of 7 items (whatever that means). So I installed Schaps latest Comm Manager and it worked fine.

Well, guess what, now there's a daemond that starts on boot and the phone app is different (another bug is that the text on the phone app buttons remain in the 3 theme although I changed back to black, but that's minor), but now I cannot replicate the no incoming calls during HSDPA error.

Apparently they've added something that makes the phone connect properly to their 3G/HSDPA network for call handling. Now I've got full HSDPA speed and no problem on incoming calls (plus still have Black Dymond's great VOIP/SIP WM6 solution).

[Quist]

Ok, as a noob I of course missed the fact that the daemon starting at boot is Voice Commander. Still the actual phone app/dll is somehow different with this ExtROM and it's solved my problems.