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Posts: 305 | Thanked: 290 times | Joined on Jul 2012 @ Graveyard
#31
3G is Release 99 UMTS. Whereas, 3.5G is WCDMA (enhanced UMTS) with HSDPA and HSUPA enabled. There can be Node Bs (BTSs) with 3G enabled (without HSDPA/HSUPA) and in such a case, it should show 3G. If your serving Node B is HSDPA/HSUPA enabled, it should show 3.5G. and if your serving cell is not HSDPA/UPA enabled, it shouldn't show 3.5G. This is perfectly normal. ie, 3G-3.5G switch is determined by the properties/capabilities of your serving Node B.

Remember, with Release 99, you can only get downlink speeds only upto 384 kbps whereas with HSDPA enabled, you can get speeds upto 14.4 Mbps (without DC/MIMO). And yeah, this is the theory part.

My girlfriend has a Nokia 5800 in the same network as my N900 and she does not have any problem to get stable internet access in the big city. Her phone shows 3.5G constantly in the display when connected to the internet.
^^ I find it a bit weird though...
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Last edited by ranbaxy; 2012-12-28 at 11:24.
 
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#32
Originally Posted by ranbaxy View Post
3G is Release 99 UMTS. Whereas, 3.5G is WCDMA (enhanced UMTS) with HSDPA and HSUPA enabled. There can be Node Bs (BTSs) with 3G enabled (without HSDPA/HSUPA) and in such a case, it should show 3G. If your serving Node B is HSDPA and HSUPA enabled, it should show 3.5G. and your serving cell is not HSDPA/UPA enabled, it shouldn't show 3.5G. This is perfectly normal.

Remember, with Release 99, you can only get downlink speeds only upto 384 kbps whereas with HSDPA enabled, you can get speeds upto 14.4 Mbps (without DC/MIMO).

And yeah, this is the theory part.
Thanks. Anyway I don't care if my phone shows 3G or 3.5G. I only want to have a stable connection, and it seems that in big cities (where 2G,3G 3.5G nodes co-exist) the intenet connection freezes when auto-switching from 3G to 3.5G and then back again after an inactivity period. By the time being, the only workaround is to use the 2G network, which works OK in big cities, but is very slow.
 
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#33
Originally Posted by ikerrg View Post
Thanks. Anyway I don't care if my phone shows 3G or 3.5G. I only want to have a stable connection, and it seems that in big cities (where 2G,3G 3.5G nodes co-exist) the intenet connection freezes when auto-switching from 3G to 3.5G and then back again after an inactivity period. By the time being, the only workaround is to use the 2G network, which works OK in big cities, but is very slow.
AFAIK, 3.5G and 3G doesn't co-exist on a BTS (Mac-hs architectural changes needs to be done for HSDPA/UPA). If you are seeing a 3G to 3.5G switch, I believe it should be a serving cell change or you are downloading something after staying inactive for a while? If you are facing difficulties in accessing 3.5G network, it should be because of network overload - though I agree it can't happen always but you've also mentioned that you are able to re-register on to 3.5G network after a while. Your operator should be able to fix it if it is a bug at their end once you let them know the issue because I don't see any reason why a particular phone should be denied access to 3.5G network...
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Last edited by ranbaxy; 2012-12-28 at 11:29.
 
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#34
Originally Posted by ranbaxy View Post
AFAIK, 3.5G and 3G doesn't co-exist on a BTS (Mac-hs architectural changes needs to be done for HSDPA/UPA). If you are seeing a 3G to 3.5G switch, I believe it should be a serving cell change or you are downloading something after staying inactive for a while? If you are facing difficulties in accessing 3.5G network, it should be because of network overload - though I agree it can't happen always but you've also mentioned that you are able to re-register on to 3.5G network after a while. Your operator should be able to fix it if it is a bug at their end once you let them know the issue because I don't see any reason why a particular phone should be denied access to 3.5G network...
I agree, I also don't see any reason for this behavior and I am a bit surprised with my old good N900. But my girlfriend's Nokia 5800 does not have this problem and it is always connected. I do not think that it is an operator problem, maybe a combination of facts that make N900 don't correctly negotiate the data transfers or 3.5G protocols after some time of internet inactivity. I don't know, but I am out of ideas to fix this.
 
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#35
When it shows 3.5g, the radio is actively transmitting and "online". When idle for awhile it drops to standby and you see it as 3g. Upgrade from transmitting data in 3.5g vs 3g depends on operator thresholds and settings. Likewise for 3.5g to 3g move. There's a delay when network decides to switch you to 3.5g, depending on operator 1 - 5s. In overloaded areas it might be closer to infinity delay, during which time no data moves


Power use in 3.5g mode is pretty high, a bit higher than having a voice call active. Anyway, since the decision to drop down to idle 3g depends on data transfers, a "ping -s 1400 google.com" in a terminal might be enough data to convince network to keep you on 3.5g. As I said before, however, you'll get less battery life doing that then the declared talk time.
 

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#36
Originally Posted by shadowjk View Post
Power use in 3.5g mode is pretty high, a bit higher than having a voice call active. Anyway, since the decision to drop down to idle 3g depends on data transfers, a "ping -s 1400 google.com" in a terminal might be enough data to convince network to keep you on 3.5g. As I said before, however, you'll get less battery life doing that then the declared talk time.
Thanks a lot for your answer. The workaround works well, the phone keeps in 3.5G mode if there is a ping working in the background. However, as I have a limited data plan, I have changed the command to "ping -s 1 -q 8.8.8.8" trying to make the data transfer smaller. It works OK. One question, is it possible to ping the server with a different period of time (not every half second)?

In addition, when I use the N900 as a modem for my PC, how can I keep the data transfer with a ping?
 

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#37
Well, we can summarize the workarounds to keep the phone in 3.5G all the time when connected:

The workaround in Linux is as shadowjk previously said:
"ping -s 1 -q 8.8.8.8"

This can be used when the connection is made in the phone and when the phone is used as a modem for a Linux PC.

When the phone is connected as a modem to a Windows PC, the command (in the windows prompt) is:
"ping -l 1 -t 8.8.8.8"

However, although these fixes can be used as a workaround, I'd like to know why this is happening to my N900. I have made some research and tests, and I have seen that two phones (N95 8GB and 5800) with the same network provider as mine do not have any problem when switching from 3G to 3.5G in the same area as my N900. Therefore, although my N900 is working correctly in some areas (mainly small villages and rural locations), it is failing in some cities, independently of the time of the day, and where other (and older) phones work perfectly. It is clear that there is a bug in the celullar firmware of my N900 (or in the hardware) and I don't know what to do. Does anybody have a similar problem with this phone? Did Nokia ever talked about the problem?

Thanks a lot.
 

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#38
I've never found or seen a phone so far that doesn't have issues like this, if not on one operator in one city, then on another operator or other city..
 
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#39
Originally Posted by shadowjk View Post
I've never found or seen a phone so far that doesn't have issues like this, if not on one operator in one city, then on another operator or other city..
Really? Indeed, I've also seen that the N95 8GB that is correctly working in the big city cannot connect to the 3.5G network in the village where my N900 works perfectly (the N95 it falls back to 2.5G when an internet connection is stablished in that village). It is amazing for me, isn't it? It seems that the UMTS standard is not perfectly defined or implemented by all the phone manufacturers, network providers or cell towers.

Regarding my N900, maybe it is only bad luck in the coincidence of a given network provider and the city. Now I'm writting from its internet connection while a ping is running in the background to keep it alive.

Cheers!
 
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