[matty658]

Hi all

I gather now that when outside of 3's own network coverage, the phones now roam onto Orange's network. Do calls handover when going out of 3's own coverage ?? I remember originally with O2, handover wasnt possible and the call was dropped?

Thanks in advance

[3GScottishUser]

Hi Welcome to Talk3g.co.uk!!

AFAIK there is no difference in the handover with Orange. The phones cannot be registered on two Home Location Registers at the same time so when a call on 3's network drops out of coverage there has to be a handshake and authentication process to access the Orange GSM network. This process takes a few seconds so inevitably any call in progress would drop.

This is unique to 3 as they dont own a GSM network in the UK. All of the others have both UMTS (3G) and GSM and a single HLR seves customers for both so seamless switching between networks is possible.

You experience the same situation when roaming abroad, calls drop as one provider takes over from another.

Hope the above helps.

[getti]

You DO get handover now between Orange and 3 so your call will not drop after swapping.

This was a great part of the deal with Orange. I have no clue about HOW this happens but just know it does work now.

I have seen it many times

[matty658]

Thanks for the info chaps.

Only ask as my other half is contemplating on leaving O2 for '3'. Only problem being there's no current/proposed O2 3G coverage where she lives. She wants a Nokia N73, but seems a little pointless if there's no 3G coverage ?? Little concerned from reading about, that if she's goes with O2, the battery life on her phone will be poor, as it'll be searching for an O2 3G signal all the time at her house wont it ??

3's coverage in her area is OK, but there's a few blackspots on her way to work, but if the handover works, she shouldnt have a problem on '3'. Their half price tariffs are quite attractive at the moment. All O2 can offer is a free bluetooth headset, which she already owns !

[Ben]

Battery life will only be poor if you are on a 'fringe area' where the phone constantly switches between weak 3G and 2G.

Have you considered the other networks, namely T-Mobile, Vodafone and Orange? T-Mobile especially have 'Web n Walk' which would really let your other half get the most out of their N73, in terms of data usage, without costing the earth - if 3G coverage is there. T-Mobile have their streetcheck service so you can pop onto their website and check the coverage of your 3 most important postcodes.

Three's relationship with Orange does seem to be going well so far. I'm not sure about the handover, though it may well be possible by now, but I know that at least one Three user has received EDGE service when outside Three's coverage. EDGE is an upgrade to GPRS that only Orange have deployed, but I think coverage is limited so it probably shouldn't factor into your decision.

I definitely commend your choice of handset, the N73 is a stunner.

Good luck!

[getti]

This will sound REALLY odd as i work for 3... but if you are after the N73 as Ben suggests check out T-Mobile as an option.

Online orders for Flext get 6 months 1/2 price so £17.50 which is what 3 offer and nothing can beat Web n Walk for data!.

I have cancelled my 3 contract which i have had for over 2 years now and have a N95 which i am using T-Mobile on because it is so cheap and.... data is really importaint to me to be able to update Today On 3G on the move with a laptop.

Customer service is based in the UK so you will get someone who understands your questions and they are very cheap to use abroad too.

Many people complain about 3CS which is why i try to help as many people as possible with any questions they have either in store or online with forums such as Talk3G... but at the end of the day T-Mobile is an all round winner.

I got a phone call from them 1 week after joining asking if i had any questions and how i found using the service so far which was nice of them. Also i have emailed them questions on the My-TMobile website and have had a call within 2 days talking me though anything.

Yes i like the service that 3 can offer... but from an unbiased point of view as i like to give my choice ould be T-Mobile.

Might want to hold off 2 weeks though for the Nokia N95 which is coming out?

[3GScottishUser]

There is no possibility of a seamless handover between UMTS and GSM on different networks. Calls always drop when roaming happens and 3's customers roam when outwith 3's own coverage.

It's technically impossible as the phone can only transmit and receive on one set of frequencies at a time.

Every new connection to every mobile network needs to be validated. The handset IMEI is used to ensure its a valid customer (not a stolen handset for example) and once that process has been completed the user is placed on the network's Home Location Register. A user can't be on two HLR's similtaniously because that would confuse the issue as to where the call was terminated!

If one considers how cellular systems work the notion of a seamless switch between two separate networks (intra-network switching) is not possible. There is no evidence anywhere on the Internet to confirm that this is technically possible but plenty of evidence to prove that networks with both UMTS + GSM can support this function.

[Ben]

The original PR stated:

"Under the terms of the agreement, when 3 customers are outside areas covered by the 3 network they will seamlessly roam onto the Orange network, where they will be able to continue to make and receive voice calls, send and receive text and multi-media messages, and access GPRS data services."

Of course, this doesn't distinctly guarantee that a call will continue across the handover, but Orange has a much more modern GSM network than O2 and it's quite possible that technical solutions now exist to permit this. Never say never.

[3GScottishUser]

The key word in the press release is 'roam'.

Roaming means reregistering on a different network and that has to happen before a call is connected. It goes without saying that it takes time to validate a user and that is the reason calls drop!

"seamlessly roam onto the Orange network" simply means the phone user does not need to effect the change, the phone automatically adjusts itself.

As ever the devil is in the detail but I have yet to come across a technical explanation of how seamless inter-network handovers are achieved or any document detailing an instance of it having been successfully implemented.

[getti]

When i go into work on Monday (i got the weekend off :) ) i will record the seemless handover in action if you like

[3GScottishUser]

When i go into work on Monday (i got the weekend off :) ) i will record the seemless handover in action if you like

How can you do that.... arrange for 3 to switch off a transmitter specially?

How would you know a handover has taken place when you have the phone to your ear!!

[3g-g]

Seamless is as the word suggests, without a break.

Three -> Orange ISHO without fail is in place, I've tested it myself.

[getti]

:) :) :) :)

[3GScottishUser]

I hate to be so persistant but if this intra-network seamless switching exists can someone produce a technical explanation of how it is achieved and a reference to the technology employed.

Cellular roaming between different networks does not perform seamless handovers (calls always drop because they are based on circuit switched technology - even 3G) although the switching between networks is 'seamless' in that the user does not have to make any changes themselves.

[3g-g]

It works in the same way as your handing over between any of the current 3G/2G network operators just now, you handset has the ability to monitor both frequencies in multi-mode and the network deals with the specifics of the switch, being circuit switched or packet switched has nothing to do with it.

If you're wanting a technical explanation I'll dig around and find the documents in work during the week and post it up.

[3GScottishUser]

If you're wanting a technical explanation I'll dig around and find the documents in work during the week and post it up.

That'll be interesting.... remember it's roaming though.... not a simple handover.... it requires handshakes, authentication etc...

Look forward to seeing the information.

[bsrjl1]

3GSU we've been through this before, there's no need for handshakes, authentication etc.... In a voice call, the handset measures 2G & 3G neighbours that the RNC tells it to. When it's got no alternative 3G cells & the current one is fading, the RNC makes a Inter-System HandOver decision.

The 3 MSC via a signalling connection to the Orange/O2's MSC (they're linked), gets it to reserve a timeslot over the air, from the BSC to the MSC & between the O/O2 MSC & 3 MSC. Once this is done, the 3 RNC instructs the handset to jump over to the O/O2 frequency/timeslot & carry on the call.

Easy eh? PS is simple, stop the data transfer, handover & resume. OK not every handover will work, it takes a little time, O/O2 might not have space. If the handset supports compressed mode it stands more chance.

[3GScottishUser]

Yes we been here before.... it's not an exact science when switching from UMTS to GSM on a network owned by a single operator and a bigger issue when roaming is involved.

The fact is that a user can't be registered on two networks similtaniously and to switch via roaming there is an authentication process.

I appreciate the explanation but still await some documentation reference to the process of roaming UMTS to GSM handovers. Its a long shot as it not something that is common outwith Hutchison's operations but if it is happening it will have been tested and documented somewhere on the Internet.

[bsrjl1]

Just because they're different networks makes no difference. 3's HLR is the only place the user is registered. As far as the handset is concerned, the O2/Orange network is effectively 3's GSM network. There is no difference between ISHO Orange 3G-Orange 2G & 3 3G-Orange 2G.

It's not like roaming on holiday where you loose a network, drop the call & then register onto another one. I've had a 3 handset for a couple of years, and it's worked since day 1 (although it's got a lot more reliable now).

[getti]

Surely thats an end to it now though? Users (including myself) have seen or had a handover work on 3 to Orange.... and a member of Orange has backed this up from their end

[3GScottishUser]

Orange or 02 dont allow access to their networks without handset validation.

I hear what is being suggested but to be convinced I need to see a published technical account of how intra-service handovers are achieved when they involve 'roaming' from one provider's network to another. Like everything else the solution can be made to sound simple but in reality the true explanation will be somewhat more complex.

The elusive technical explanation must be out there somewhere.... closest I have come is a paper by Huewai but their solution was theororetical and we know neither 3 Uk, 02 or Orange use that hardware vendor for the supply of technology.

[Ben]

The subscriber has been verified when connecting to Three, or Orange, whichever - the handset is seeing them both as the same network.

While this wasn't possible back in the day on Three, for whatever reason, the personal experiences of handover here are enough evidence to conclude that the handover now works - technical explanation or otherwise.

[3g-g]

I'm not going to go putting up technical documentation from work as it's not allowed, however as brsjl1 has posted the sequence of events noted are what occurs. Three and OUK are physically connected to each other, their networks talk to each other, and as far as the handset is concerned it has a list of preferred and allowed networks to connect to, in this case, Orange's 2G. On the Orange network side of things their HLRs have a list of every active IMSI belonging to Three, so when one comes along requesting access it's allowed. The only exeption to the rule for roaming is that if a Three sub loses Three coverage and finds only a Orange 3G cell it's not allowed to connect and will drop. You won't find any documentation on the interenet, because, as has been mentioned a few times now, to the phone, it's all one big network.

[3GScottishUser]

One big network eh?

Ofcom require validation by all networks for 'roaming' users as a mandatory requirement of their licence. So it's like an airline handover... your bags get screened athough you think you seamlessley walk through to another carrier.

3 and Orange or 02 can make whatever arrangements they like but each have to validate a user to access their network and that is where the 'seamlesness' is a problem. No user can be on two networks similtainously.

I doubt if this is a huge issue for 3 now with their 3G footprint.

[3g-g]

3 and Orange or 02 can make whatever arrangements they like but each have to validate a user to access their network and that is where the 'seamlesness' is a problem. No user can be on two networks similtainously.

Yes, each network has to validate the subsciber, but have you any idea how many times the network is measuring signal levels, cells talked too, handover stats, neighbour cells, signalling issues? Are you aware of how quickly this is done? It's a constant thing, it's not that it takes a few seconds, we're talking the speed of light here!! The Orange network is aware of all the Three subs, so when Three see the handset receiving a lesser and lesser signal level and a timing advance increacing it looks to hand over, and if the handset reports back that it can see this strong signal coming from Orange 2G (because each Three SIM has had an OTA update telling it to look for that specific network code) it tells its home network, it sends the details to Orange's MSC/BSC, the handset is confirmed as allowed (this is happening while you're still on Three for the call) the timeslot is allocated, the message is passesd back to Three, then to the handset where the handover/off is initiated, call now on Orange 2G, the call is only ever on one network at a time, Orange say hello, Three say goodbye.

It's not the same as when you turn up on a foreign network, the reason for delay there is the foreign network going back to your home network saying "Hi, I've this IMSI/MSISDN here that belongs to you, what's he allowed to do?" you're looked up, your home network tells the foreign one what you're allowed, make calls, send texts, send MMS etc and send the info back, the foreign network then stores you on it's VLR till such time as you leave. You could be from any GSM network in the world and that takes time, and is not what happens in the Three/Orange agreement, there's a specific number of Three subscribers, so Three have told Orange about all of them and Orange are ready to expect them at any time, hence no delays or drops!

I'm afraid you're just going to have to take our words for it!

[bsrjl1]

3GSU the problem is you need to understand that the 2G roaming agreement involves a lot more than just letting 3's subs onto the Orange network. Part of this is to allow 3's MSC to pass authentication data (TMSI) across, so there is no need to re-authenticate. They're getting paid so why would they care?! Also they need to keep 3 updated with details of any changes made to the 2G network - LACs, CIDs etc..

If you don't believe us, who are you going to believe?

[Hands0n]

It is, indeed, a pity that some kind of White Paper on this does not exist as it is not exactly trade secret, merely a rather glowing example of technical collaboration between two disparate commercial entities. The network diagram that y'all pointed us to in another thread was very enlightening. Generic enough to have been any mobile network but also specific enough to highlight the technologies involved. A similar document on this collaboration would be a superb piece of information.

Vis a vis 3 and Orange, it also holds great hope for a future where such seamlessness could provide the answer to a truly 100% coverage of the UK geography. This would have personal and national security benefits. Technological excellence is always beeing hampered by the Finance Department and commercial aloofness. More collaboration like this would be not only to the UK Customer's benefit but a model for the rest of the world, perhaps. An idyllic proposition, perhaps. But if one never dreams nothing ever happens :)

The detail is fascinating - it is "merely" status message passing, the Financial District has been doing such realtime transaction messaging for decades. Nice to see it coming into the IT world at last. For sure it is a lot of data (so is Global Foreign Exchange trading) and necessary to be very realtime (ditto FX), the technology to do this has been there for simply ages. That the mobile networks have incorporated such techniques and technologies is a very good omen for the future of such networking. That it is quite so much "intelligence" (i.e. precisely who you are in the form of handset identity) is worrying in terms of privacy. If that data is stored then the mobile ops, at least, have an audit trail of pretty much where you've ever been, and when exactly! But thats a whole other discussion!!

So, any of you chaps up for writing that White Paper :D

[Dusty]

Ill just be happy when I can roam on Orange. You lot seem pretty technically minded, how long is it likely to take?

Someone mentioned on another forum that 3 and Orange have agreed to enable 100,000 3 customers to Orange per week? True or not I don't know :confused:

Ive gotta say I always questioned 3's choice of roaming partner in o2..... anyhow, I'm interested to know if Orange was chosen because of its network capacity and coverage or whether it was down to cost... I would have thought the might of Voda would have snatched it up?

[3g-g]

Ill just be happy when I can roam on Orange. You lot seem pretty technically minded, how long is it likely to take?

Someone mentioned on another forum that 3 and Orange have agreed to enable 100,000 3 customers to Orange per week? True or not I don't know :confused:

Yes that's about right, there's around 3.5million subs to be migrated, and currently around 2 million have already been moved AFAIK, you may already be one of those! Unless you're aware of poor coverage areas on O2 that you experience via Three?