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Posts: 20 | Thanked: 3 times | Joined on Sep 2007
I had the same problems for a long time - all solved now mostly.

I troubleshooted it for a long time with no help from WIND - I am on unlimited voice and data plan.

My progressive and compunded conclusions were as follows:

On the network that has both, the provider often uplinks to 3.5 on download requests - in some cases (mine) always - which results in no stable internet over 3G (because of the ping pong between 3 - 3.5).

I thought my phone was faulty, got a new SIM etc.- with not much of an improvement. Some improvement was noticed when new SIM cards were used and set-up with no PIN. So I am not using PIN at the moment as this seemed to help reliably. So not a SIM card issue - but certainly a PIN implications (possibly with timing, delays, handshake negotiation etc).

Signal strenght issues (too low of a signal strength resulted in frequent failures when switching to 3.5 G and thus disconnects).
Too low a signal in 3.5 mode resulted in icon showing 3.5 while negotiation continued (with no data sent) untilit went back to 3G mode and then back to 3.5 etc. Forever.

Possible energy management issue with n900 itself - I suspect that if everrything was on (bluetooth, wifi, gps, led, sound, etc.) ans 3.5G mode required great deal more juice - the N900 was not responsive enough in providing it. This likely contributed to the frequent disconnects. Turning off what I have not used, and running with screen-off resolves most of the problems for me.

Rinning Titan's Kernel with overclock helped a lot as well. Due to the phone being more responsive (things take less time) as well as
realizing that I have power issues while trying to run at high frequences. This helped me realize the power management contention issues that came into play even more when 3.5G mode was called on (I have read that 3.5 modem can use up to 2A at the time! ).
This was more pronounced when I understood that the phone would up-shift CPU frequency when I tried to download data - resulting in both modem and the CPU asking for more juice at once. Now I have 2 energy/performance specific modes that I can alternate between as needed.

6) There are problemes with phonenet that I discovered. This is likely due to set-up and tear-down issues with network establishement using the defined APN that is used for the Internet specific activity. This resulted in freez-ups and crashes in rfconnect.ko module (as far as I recall the names now).

My testing suggested that whenever I use the ppp connection
instead of the default "Cellular Data" my connections would be much more stable and predictable.

7) I have added a new packet connection as a redundant APN
with the same configuration data - just a diferrent name.
I made both of them not start automatically anymore.
This allows me to use my own APN whenever I use the Web from the phone itself, while the modem and phone can use the "Cellular Data" default APN. You may think that I am insane - but this helped me the most in using the 3.5 data on the go.

My conclusion is that default "Celluar Data" APN configuration is used to switch to 3.5G mode (I could call it data mode where possibly PIN, but certainly user/password/IMEI information is checked/verified on handshake). This happens automatically and on some pre-determined timing. The phone will connect every so often to the tower to check/confirm signal strength, pick-up SMSes, etc. This takes precwedence over any data connectivity - and it seems synchronous activity (no multiplexing capabilities when it happens) that is interrupting what else was happening. During this activity my data connectivity would suffer (frequent disconnects and delays) the most. By forcing my own APN (same config - diferrent name) before connecting to the web - the phone signaling/management activities no longer impact my data connectivity as much - as if my custom 3.5 G APN connection is not teared-down - when signaling on 3G occurs..

8) I had a lot of problems when I had both 2/3G selected as well - this is because phone keeps getting bombarded with signaling data from all of the networks. The stronger 2G signal would often kill my 3G (and even more often my 3.5 G connections). Sometime this would be resulting in data connectivity loss - which had to be
re-acquired (after all timeouts and handshaking had a chance to complete) resulting in terrible end-user experience. I never had that problem before with 2/2.5 G vendors/phones.
Sometimes I would lose my "Home" network and the phone app would crash on occasions as well. THis was happening even if the phone was stationary and manualy tied to my "Wind Home" zone. The phone would switch to "Wind Away" and rarely back (or crash completeley). Situation improved when I disabled 2G completely and made my network provider "automatic" but 3G only.

9) Finally I have asked Wind to supress roaming on my account completely - no switching my phone to other vendors at all.
This helped a lot too. I can always enable it back when necessary for travel, etc.

My final conclusion is that 3G networks (i.e. Wind) are 3G in name mostly. My phone only works in 1 room of my house - the signal can't penetrate 2-brick wall.

The signal is shaky, their equipment suffers form lots of fluctuations and failures. It seems to be load affected, weather affected etc.

They have ISP issues - with DNS servers, NAT gateways etc.

They filter and throttle traffic - which results in users perceiving "frequent disconnections" - as I was.

They purposely slow us down, introduce interruptions in larger transfers - sending bougus packets to the phones/modems - which results in various recovery specific delays and/or crashes.

They periodically diconnect users from their APNs forcing reconnections (specially in streaming and large downloads) - with no reagard for what one was trying to do in the meanwhile, etc. And they take customers for granted.
The network providers are mostly at fault here!

All of the above results with us being unhappy with the n900.

In my opinion, N900 has some problems with energy management (including charging/BME defaults/behaviour) and predatory on-demand governor behaviour (that can be managed by more knowledgable users only) and with the APN stack conflicting with
regular phone behaviour on poor networks (this is not as profound when using phonet with PPP).

I could use ppp instead of APN on the phone itself (much more resilaiant and reliable), but I see no need to do that anymore, as my data connections are much more satisfying.

Nowadays the one room my phone works in, has a wifi router connected to it and a phone number forwarded to my home phone - when I am in the house.

In a nutshel - a lot of usabilty issues are in-fact sophisticated and compunded problems.

For instance default USB driver in windows (any version) needs to be updated with a special hotfix from Microsoft to avoid frequent disconnects on larger downloads - yet thouse using n900 to tether are likely to blame Nokia for it.

N900 is a best phone money can buy - but it needs a passionate owner who is technically savy to appreciate that.

Nokia is a visionary with its 770/800/900 revolution - but those that do not know linux, or telco implications are bound to blame the phone itself and a company that made it.

Posts: 52 | Thanked: 25 times | Joined on Dec 2009 @ Texas
3G and 3.5G are the same network on the same base station. 3.5G is HSPA. HSDPA or HSUPA radio bearers are invoked when there is sufficient data in the buffers (at either end, handset or network) to require a higher data rate other wise it will close the 3.5G HS(U/D)PA channel to save power and resources.
Posts: 20 | Thanked: 3 times | Joined on Sep 2007
I re-read the post and realized that it might be a bit confusing.
For clarity: I have described in one post everything that occured over 2-3 month time period. I am not sure what exact role each item had palyed (although each one seemed to help somewhat), especially that I had gone to 1.3 in the meantime.

For me it was a progressive affair.

I just want to reiterate that I have NO issues with n900 anymore - when it comes to connectivity - that is unless the network operator terminates my connection.

This is true for data connection on the phone itself with my custom/redundant APN (obviously with the LCD on), as well as for the use case when the n900 acts as a 3G WAN modem - connected to my Tomato router (with LCD off, and charging off of a self-powerd hub, that sits between the router and the phone)..

Posts: 20 | Thanked: 3 times | Joined on Sep 2007
Originally Posted by siperkin View Post
3G and 3.5G are the same network on the same base station. 3.5G is HSPA. HSDPA or HSUPA radio bearers are invoked when there is sufficient data in the buffers (at either end, handset or network) to require a higher data rate other wise it will close the 3.5G HS(U/D)PA channel to save power and resources.
Thanks for sheding some light here!
I am sure you are technically and factually correct.

Often though such knowledge does not manifest itself the way your post implies ("it should just work - same network same base station") to users that suffer from connectivity issues and can't get those resolved easily. So some question still remain.

If one has frequent connectivity issues - would that not impact "sufficient data in the buffers" on both ends? They just know that even though they have asked for a huge chunk of data to arrive it is just not comming to their n900.

If there is sufficient data in the buffers on the other hand - would modem in 3.5 not need more power to receive/transmit?
What happens if it does not get that power quickly enough?

I lived through it (including frequent crashes while attempting to use MobileHotspot) - so I can empathise with those that experience thouse issues. They are real, and reflashing alone did not help in my case.

The only thing I saw was an icon going from 3G to 3.5G and bars for signal strength flickering like a set of christams lights, no dat was arriving and no meaningful help from anyone was forthcomming.

I think that understanding of what is going on is very important, but that knowledge itself will not solve the practical end-user impact.

If you put your phone in super starving mode on overclocked kernel you might be able to see how 3.5 mode shuts down your phone which was working fine in 3G mode.

Maybe the power management of the n900 is not anticipating/not aware of "sufficient data in buffers" causing some instability at times. Or maybe ppp based 3G modem connections with no wlan0 interface in the picture are more resiliant. Or maybe another APN, or no 2G switching, etc...

I might be way off base with my observations, but...
I had those issues and although I believe that they are mostly network operator specific - what little I have done on my n900 has seemed to have had helped me.

Anybody's else milage might vary.

Posts: 52 | Thanked: 25 times | Joined on Dec 2009 @ Texas
Sorry I was not discounting any issues that you were/are seeing. I was mainly just highlighting that 3.5G is more just a higher data rate channel with in the 3G/UMTS system.

Some of your questions revolve around mobilehotspot which is somewhat more complicated (than I really understand) and I can fully understand where processor speeds and overclocking would have an affect, after all the handset is routing traffic from one interface to another.

I can also understand when a redundant APN could have some impact when using mobilehotspot/teathering especially if it is not able to detect the APN stauts properly. I myself have seen issues when teathering where my PC is trying to use on APN and the handset is using another.

I believe you said you were on Wind (Canada) mobile which is still a relatively young network, so may still suffer slightly from growing pains.

Again sorry I'm not much help, but with out mobile/cell network traces its hard to really see whats happening
Posts: 20 | Thanked: 3 times | Joined on Sep 2007
There is nothing you need to be sorry for.

I have no problems anymore - but (from experience)
I am certain that what
others are describing is very real.
Sorry if I came accross too acusatory in my post.

I was simply trying to add some context to my past observations, which
obviously become more prominent when the system is being pushed
too much.

Now that I understand all the implications and can use my phone as 3G modem and while it is charging (rather than discharging as was the case under MobileHotspot) - I couldn't be happier with my n900. I hope that listing what I did may help other users as well.

Thank you for your contribution, communication skills and civility.

Posts: 8 | Thanked: 0 times | Joined on Dec 2009
i dont think its t-mobile's fault, because i find it odd that the phone only gets the connection error, general error, and etc only after the battery drops down to 50%. on a full charge, every call works on 3G. but still not internet.
and even though you may say that 3.5G is the same as 3G, can you explain as to why webpages won't load at all in 3G? and loads only when it goes up to 3.5G?
Posts: 48 | Thanked: 26 times | Joined on Feb 2010 @ UT@NL
I don't have that.. for me, I had the issues with whatever battery load. I Think I solved it by adding a second APN though, thanks for that tip!
Posts: 49 | Thanked: 7 times | Joined on Apr 2010
in order to stay connected to 3.5g, would it be possible to make a widget which would activate a small constant data stream for when 3.5g needs to be maintained? as when i am connected to facebook chat over 3g, in times when it switches between the two i dont seem to receive messages. also another one for when downloading torrents, when you lock the screen, the speed seems to drop dramatically, eg from 700kbps to around 20kbps... i know both would waste battery life but for times when connected to power, these would be very usefull. Also same problem occurs when tethering with computer... seems to stay on 3g, and only switches to 3.5g when i use something on my phone
Posts: 181 | Thanked: 82 times | Joined on Jan 2010

I have my N900 since 2009 (3 years now!!). I have never used 3G internet connection because I did not have a data plan and I always had a close Wifi. However, I have just got a data plan and now I am having the 3G issues that you comment on this thread.

When connecting in a rural area (a small village) everything goes perfectly. The N900 is in 3G mode and shows 3.5G whenever you need data transfer (both using N900 as a modem for my PC and also using internet on N900's browser). There is no delay and you can be connected with perfect stability for a long time.

However, in a big city, things are totally different. The phone correctly stablishes the data connection and shows 3.5G, and you can start surfing the internet without problems (again, no difference in using it as a modem or surfing inside N900). But after a while not using the internet, the phone switches to 3G and it is unable to go back to 3.5G when internet access is again required. The connection is hang and the only way to return it to life (apart from disconnecting and connecting again) is changing the network mode of the phone from Dual to 3G or viceversa. However, after a period of inactivity, the internet access is again frozen.

I have read the whole thread but I did not find any definitive workaround for this problem (except from changing the network to GSM/GPRS/2.5G, where the internet works correctly but very slow).

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.

Any idea or workaround to use internet in N900? A good idea could be disabling the 3.5G (HSDPA) in big congested cities and forcing the phone to transfer data over 3G (UMTS), which is slower but faster than 2.5G. However, I do not know if that is possible.

Thanks in advance.

P.D. My N900 is recently reflashed so I don't expect software problems. Anyway, as I have said, it perfectly works in low traffic areas.

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