[Hands0n]

Here's one for those in the know - which obviously is not me :p

This question came to mind today while using the Macbook Pro with my Nokia N95 on T-Mobile Web 'n Walk Plus. I have had, in the near past, speeds of up to 1.4Mbps downstream. Today, however, everything seemed slow and so I ran a test on Speedtest.net (my current fave). Immediately I could see that I was on standard 3G speeds and ping times. Strange, on a Sunday morning with [I'd imagine] not many people up and about.

So I disconnected the GPRS session and caused a re-dial. This time Speedtest.net gave much better results. Nothing had changed apart from renewing the "modem" connection.

Which brought me round to thinking about when the HSDPA is actually invoked. Is it at session set-up time or does HSDPA switch in and out according to prevailing conditions and circumstances? Should I have kept on -line and hoped for HSDPA to kick in, or is the cleardown/set-up the best/only way of getting it?

[Ben]

On my Voda kit, HSDPA only kicks in when data is being transferred - probably to free up resources on the network. There's a slight delay during the switch if the connection has dropped back to 3G. It wouldn't bother most people, but I always leave a ping running.

[miffed]

I have wondered about this myself - my Ameo seems shows a 3G indicator on standby , then changes to an HSDPA indicator when data is active, I have noted that it seems to drop back to 3G as soon as it finished that particular job - suggesting that HSDPA comes on "by demand"
Having said that though ,there has been occasion when I have had an HSDPA indicator but only got 3G speeds - so I am not sure TBH

[Hands0n]

I know I got HSDPA on the second connection attempt - but on the first while running speedtest.net it did not kick in with the higher speed (I ran speedtest a couple of times).

The version 11 firmware of the Nokia N95 does not show when you're on HSDPA but version 12 [allegedly] says 3.5G when its in high-speed mode. I'll have to run some more tests.

My billing date is 15th of the month - so as of 16th October I will run my MBP using HSDPA exclusively to see how much data I really use to see if I can hit the 3GB bufferstop. I don't think I will, even though I do download quite a few bits and pieces. I'll post something about it at the end of the experiment.

[getti]

I will be checking out 3's Turbo3G (HSDPA) network in about 2-3 weeks when i go to London for the Symbian Smartphone Show. Rumors are they are planning to show a iPhone like touch screen device thats HSDPA!.

Anyhoo i will be on my MacBook and using my 6120 (or U990 if i get in time) and using that as a modem so can also post my findings :)

[bsrjl1]

It all depends on what the operator has set the threshold to, but as you start receiving data over a certain amount/time & you have a HSDPA Ue. it goes something like this:
IDLE-FACH-R99 DCH-HSDPA.

The Ue sends uplink quality measurements (CQI) 1500 times per second, and the WBTS uses this to determine whether to encode each packet in 16QAM or QPSK. For simplicity call 16QAM HSDPA.

If there are already 7 HSDPA users you'll get normal R99 speeds, if the cell is congested then you can still get allocated a HSDPA bearer but have low throughput. If the RNC hasn't got sufficient resources you might not get HSDPA at all.

[Hands0n]

Thanks for the explanation.

So basically the entire thing is completely dynamic and based on prevailing conditions. Nice. I didn't stay online long enough first time to make the grade, so to speak :) I think I must have had the allocated HSDPA bearer because the speed was above R99 (3G?) speeds but nowhere near what I have seen with full-monty T-Mobile HSDPA.

I would be surprised if there were many HSDPA-capable users where I was using it this morning - my settee - but subsequently I seemed to enjoy quite a good throughput for the rest of the time I was online.

HSDPA, even at these sub-2Mbps speeds, gives a good experience that I think would satisfy most folk who are used to terrestrial Broadband speeds.

[Ben]

]HSDPA, even at these sub-2Mbps speeds, gives a good experience that I think would satisfy most folk who are used to terrestrial Broadband speeds.
Oh yes definitely, it's quite fantastic compared to standard 3G and certainly anything that came before it. It's good for a VPN, it's acceptable for gaming, and it's great for browsing. Ever since Vodafone upgraded my local masts I have been a convert, and certainly a believer in the technology. Getting the same service in Spain has sealed the deal.

Still, only 7 HSDPA users at once per cell? Mhm.

[bsrjl1]

No it's 7 HSDPA users per *WBTS* at the moment - though that will change in the future, depending on when the networks upgrade their hardware.