Comments on: T-Mobile: WiFi-Cellular Launch In September

By: Justin

Justin — Wed, 18 Feb 2009 12:50:20 +0000

I run Lingo VoIP for the home phone and I also have a T-Mobile UMA device. I have never had a single issue with quality with either the VoIP or UMA devices within my network. Of course, I’m running a Fios connection with all the hardware upgraded (non-Verizon) to business grade hardware. The gateway is setup to guarantee a minimum of 90kbps up/down to the Voip device and another 90kbps up/down to the UMA device. This in and of itself is probably why it’s rock solid for me. The wireless access point is also setup for Wireless QoS (WMM) which prioritizes the voice traffic over wireless (useful for the UMA device). I run heavily loaded HTTP/FTP servers over this connection, so for me setting it up “right” was a must. Before setting up QoS, etc, I did experience quality issues. All of which are completely resolved with my current configuration. I hope this helps!

By: astevens

astevens — Mon, 10 Dec 2007 17:45:42 +0000

Avoid this service from t-mobile. They can’t deliver in several areas. I have ha trouble ticket open since August and it is Novoember. All the old Cingular towers also do not allow UMA/GSM handoffs so that will never work. Currently, UMA is down more than it is up in central california.

By: GigaOM » T-Mobile’s WiFi-Cellular Summer

GigaOM » T-Mobile’s WiFi-Cellular Summer — Thu, 03 May 2007 15:41:56 +0000

[...] we wrote about T-Mobile’s planned Seattle trial last August, it wasn’t clear then if T-Mobile had already provisioned the service to be used outside of [...]

By: Andy

Andy — Sun, 04 Mar 2007 19:00:53 +0000

T-Mobile UMA mobile phone

Do you need to have a contract with T-Mobile to use the UMA technology. I am currently using Fido (GSM in Canada). I would like to know if the service provider needs to support UMA? Or can you use UMA on any network provided you have your own Wi-Fi hotspot.

If anyone knows please can you let me know.

Thank you.

By: William Foster

William Foster — Fri, 15 Dec 2006 23:09:13 +0000

Who manufacturer’s T-Mobile’s UMA solution?

By: Alas4493

Alas4493 — Sat, 26 Aug 2006 05:04:37 +0000

For Jesse: There is no mention of SIP in the UMA specification documents on architecture or protocols stored at http://www.umatechnology.org/specifications/index.htm. If you have a link showing its use please share it.

The Wikipedia article http://en.wikipedia.org/wiki/UnlicensedMobileAccess makes metion of SIP but only that the transport supports IMS/SIP (of course).

My comment about foreign WiFi was referring to WiFi access points that are not owned by the quad-play provider that is the mobile phone carrier. It was not meant to mean in another country. T-Mob is planning to use its large network of APs, but not to allow your home AP to be part of the mix.

Lastly let us look at the issue about VoIP over mobile phones over WiFi or Wimax. The answer is yes this can be very good. And for those countries (e.g. USA) where there are unlimited data plans this makes economic sense. However most carriers have terms of service that explicitly ban VoIP. Could they really block it? Well they could try. But then the P2PSIP working party http://www.p2psip.org/ of the IETF probably has smarter people working on the opposite tack of the problem: how to prevent carriers from impeding your communication. Skype on a beefy Windows Mobile phone is pretty good, by the way. So it does work, at least for now.

By: Jesse Kopelman

Jesse Kopelman — Thu, 24 Aug 2006 21:44:08 +0000

John Egan and Alas4493, you guys are confused. UMA does indeed use SIP. There is a gateway (Alas4493 you noted this) at the GSM switch that converts from SIP to GSM signaling. It is also incorrect to say that there is no benefit to the GSM carrier with the use of foreign WiFi. The big issue with UMA is that the WiFi calls can be billed just like GSM calls. Thus the GSM carrier can charge you on a per minute basis if he so desires. That rate could even be varied depending on IP address, so that if you call from home or a carrier owned hotspot, the call is billed as off-peak, you call from elsewhere the call is billed as peak or even roaming. UMA is a huge benefit to the GSM carrier and only of peripheral benefit to anyone else.

By: Paul Jardine

Paul Jardine — Thu, 24 Aug 2006 09:59:26 +0000

I’ve commented before about UMA being a good (short term at least) solution for Mobile operators to prevent the eating of their lunch by VoIP companies. We are going to see pure VoIP on a lot of phones once WLAN-enabled devices proliferate. That could be a big problem for Mobile operators if it works as well as Skype! UMA is a poor substitute for VoIP and it will only be of value if it competes on cost for a WiFi-based call with VoIP (probably free!). Where UMA has an advantage is in the ability to hand-off to the cellular network. That is its only, but major, selling point. People will not bother to set up and use a VoIP client if they can get the same or similar service/cost using their current phone, AND it will continue the call if they have to jump in their car mid way through. I also don’t understand Alas comment about foreign Wifi being no benefit?? What about GRX? Why can’t I set up access from foreign countries over the GRX network, thus extending T-Mobile UMA to all countries. Operators may choose not to do this, but it’s still their choice. E.g. they could have a tariff where a UMA call to your local country was 1c/minute regardless of where you were in the world. The internet as one big cell!

By: John B

John B — Wed, 23 Aug 2006 20:44:18 +0000

Unrelated to general discussion on UMA here, but related to the last comment by Alas, I’ve wondered: if the data transmission gets better, i.e. with less delay between reception and transmissions, what would stop Google from allowing Google Talk on the cellular devices (such as what they do today on Blackberries)? Far fetched, but, I think that would open up a large hole in the cellular phone companies’ marketing plans (especially if you’re getting the unlimited Blackberry data plan for $40 a month).

By: Alas4493

Alas4493 — Wed, 23 Aug 2006 17:11:13 +0000

John cleared up some of the technical confusion in this thread. UMA is tunneled over WiFi, so all the stuff that your cellphone currently transmits over the air gets sent instead over WiFi, but it's exactly the same stuff. That way with a small tweak to the phone and a new gateway at the carrier backend the carriers could make UMA happen. No SIP no VoIP no anything new. John also pointed out that 89 kbps upstream is needed, that can be iffy with low-end DSL in some countries e.g. USA.

Why do mobile carriers do it? So they don't have to build out networks to provide good home coverage, so they can cater to the one handset generation, and so they dont get as much data channel contention in their networks. Is the cost of a WiFi call less? Sure doesn't have to be - carriers can leave the billing systems just as they are.

Why do broadband carriers do it? The landline guys do it to fend off VoIP overlays (e.g. Vonage), in which case the mobile billing systems will be adjusted to respond to the 'sent via UMA' flag on the call. And to cement in the customer with one more appealing feature. E.g. The comments about TMO high churn - every additional product sold/delivered to a customer reduces their churn.

UMA over foreign WiFi, or any WiFi - no benefit to the carrier, only to the WiFi provider, provided it's not free WiFi then nobody wins (apart from the consumer). It will take a disruptive influence to make UMA over anyFi happen.

QoS is a question with UMA. Cellphone protocols are optimized for bit-level degradation, IP protocols for resilience to packet drop. Tunnel them and what do you have… a 1500-byte packet is a lot of 20ms voice samples. The net net would be a good research paper. Anyone?

UMA is actually a hack. But it is a sweet hack, and even a cheap hack in telco terms, that can make some money, save some expense, stymie some competitors in the time preceding ubiquitous and operationally efficient SIP/IMS.

By: Jacomo

Jacomo — Wed, 23 Aug 2006 17:00:54 +0000

It might not even be relavent that a Cell Carrier is even involved here, or even IMS or UMA. When these Wireless Mesh and WiMAX (Wireless Local Loop)networks are fully deployed in most major US Cities, the customer will only need to sign up for the Wireless Broadband Services for his Data (Internet and or Corporate links) and be able to DOwnload the new "Hullo" Softphone system and be off with a Voice service.

Jacomo

By: Jacomo

Jacomo — Wed, 23 Aug 2006 16:47:50 +0000

"Cingular has cancelled its UMA trial and is focusing on IMS/SIP VCC.."

I have also heard that the IMS vendor they had originally selected has come out and admitted that they would be able to provide the Handoff between WiFi and Cell. Also true IMS functionality is really 2-3 years out. So what do these Cell Carriers do to address the new WIFi/Mesh and WiMAX networks that will effectively negate value of their Data services in major Metro markets, and begin eating away at their Voice w/VoiceIP features over WiFi.

Jacomo

By: Ram Krishnan

Ram Krishnan — Wed, 23 Aug 2006 12:22:08 +0000

John,

"VCC" is not "ways away" Several landline carriers are trialing VCC right now as we speak. And even though "UMA transport" can be used to access IMS applications, that can really work only if IMS client is downloaded onto the handsets.

Cingular has cancelled its UMA trial and is focusing on IMS/SIP VCC architecture. UMA has a short window - the fact that it is not based on SIP and all carriers are standardizing their core based on IMS/SIP is going to be its death knell. Right now, the only reasons why carriers are deploying UMA is that they would like to do market research/consumer behavior studies which they will then apply as they move to IMS

By: mats

mats — Wed, 23 Aug 2006 08:42:18 +0000

In the Stockholm area where I live, the city owned company Stokab is rolling out a major dark-fiber network, which in a few years time will extend to all homes and businesses in the area.

The company leases out the fiber to about 70 ISP:s on an equal footing, giving the consumer a lot of choise. This model will probably be adopted by other Swedish municipalities as well, in effect wiring up the whole country. As I see it, UMA will be a very important component of this scenario, and the discussion about any triple play advantages above is in effect invalidated. There will simply be only two services - fiber and (private or public) wifi in densily populated areas and cellular otherwise.

By: mark

mark — Tue, 22 Aug 2006 23:37:06 +0000

I have been using a T-mobile UMA phone for about a week and I love it. I have service in my apartment where I used to NEVER have service. Also when I am out at the bars most of the bars I go to have a WIFI connection so I am able to hook up to that and have GREAT service in the bar where I used to have little to no service. I think that T-mobile is moving in a good direction with this.

By: John Egan

John Egan — Tue, 22 Aug 2006 20:49:21 +0000

I’d like to resolve some misunderstandings as to UMA, IMS, and what is possible with UMA.

First, UMA for this example, can be thought of as mostly a transport technology… to get voice (or data) to/from a terminal (handset, etc.) and a Mobile Carrier. The technology is based on mobile’s AMR CODECs (not VoIP) and GSM signaling (not SIP). During a WiFi connection, UMA terminals communicate over some form of internet connection (DSL, WiMAX, Cable) with a UMA Network Controller (UNC) located in the Mobile Carrier’s network. The UNC emulates a base station controller and base stations, therefore to a mobile carrier’s network a UMA terminal and its associated call looks like any other mobile call. This enables roaming and handover (switching from WiFi Access Point to cellular site and vice versa) while on a call.

UMA does not conflict with IMS. IMS in itself does not replace UMA. IMS is more of a network and applications oriented technology and so there really is no conflict. IMS does have VCC (Voice Call Continuity) in its definition which will enable cellular and WiFi dual mode handsets that use VoIP and SIP, but VCC is still “a ways away.” UMA can be used with IMS as a way to get a call/session into an IMS cloud through some form of gateway, just as any other legacy Circuit Switched call will be handled for many years to come. Meanwhile, IMS can still be used to deliver “rich media” and services to a UMA handset, albeit of a limited fashion when compared to handsets with an IMS client inside. But, once more, this is a ways away.

As to bandwidth usage and potential for poor communications… UMA voice calls need about 89 Kbps. Not much different than a VoIP call with SIP signaling. Each method can have higher or lower compressions, with UMA voice quality on par with VoIP at similar bit rates. Any internet problems or bandwidth fluctuation can disrupt a UMA or VoIP call, as I experience daily with Vonage. So that is not an option or solution.

T-Mobile seems to be continuing to focus on the younger crowd with their complete reliance on their mobile handset versus what can be thought of as the “hybrid” method that most others use (POTS at home, digital deskset at work, mobile outside). With UMA, when at home or the office, the mobile only user can use their WIFI connection and not use up their mobile minutes, leave their phone in its charger while speaking, and have a higher voice quality indoors. While at Hotspots, the user can once more save on minutes, enjoy whatever specials are given with the service, and have better or same as voice quality than other mobile users.

I believe UMA is not a technology that came and went before there was a market, but one that will grow in use as benefits to carriers and their highest use customers (those under 40) become evident.