A BIG week for a FEMTO standard

A little event occurred in Dublin this week that could have big implications for the Femtocell market…

As we all know, standardizing the interface between Femtocells and the core mobile network is one of the big challenges that must be met before the Femtocell market can really take off (see the UMA Today webinar or whitepaper for more info).

Well, at the 3GPP GERAN standards meeting in Dublin this week, a formal work item was started to add the necessary changes to UMA specifications to accommodate femtocells. With hard work and a small bit of luck, 3GPP could have the work completed by February of next year. This is key milestone.

I hope everyone at the meeting raised a glass of that classic Irish beverage and proposed a toast.

All dual-mode phones are NOT alike

A common misconception is that all dual-mode phones are the same. Many people consider Wi-Fi enabled phones to be expensive and have poor battery life.

I’d like to dispel this myth by making a distinction between UMA and non-UMA enabled devices. I concur that non-UMA dual-mode handsets are often higher end (and therefore more expensive) and have poor battery performance (when in Wi-Fi). However, UMA-enabled devices are often mid-tier feature phones with respectable if not ‘stellar’ battery performance.

Fundamentally, UMA is a technology for mobile operators. It is designed to make Wi-Fi (and IP and broadband) ‘friendly’ to the mobile operator. So, what is UMA’s secret?

When a UMA-enabled dual-mode phone enters a known Wi-Fi coverage area (home, office), the phone automatically and seamlessly switches from the GSM network to the Wi-Fi network. Now the connection between the phone and the mobile network is over the public internet rather than the GSM radio access network. Because it’s not used when the phone is in Wi-Fi coverage, the GSM radio is put into a sleep/hibernate mode.

If/when a call arrives for the handset, the call is routed through the UMA tunnel over the internet to the handset, and the GSM radio is not used.

This is one key element of improving battery performance in UMA-enabled handsets. By putting the GSM radio in a sleep mode, the phone continues to run a single radio. Anyone who has run their Bluetooth radio all day knows that having two radios on in a phone significantly impacts the battery performance.

Contrast this with the operation of a non-UMA dual-mode phone. As the phone enters a known Wi-Fi location, generally the user needs to turn on or enable the Wi-Fi radio. Primarily this is because the battery impact is so great that ‘automatic’ Wi-Fi usage would have the un-intended consequence of sucking the battery dry.

Now with the Wi-Fi radio is operating and associated with an access point. But to make or receive GSM calls, the GSM radio must remain on as well. In a non-UMA device, the only connection between the mobile core network and the handset is over the existing GSM link. In this case, Wi-Fi is simply a bolt-on to the phone’s primary function as a GSM communications device.

There are many implications of this ‘bolt on’ approach.

First, people with non-UMA devices don’t use the Wi-Fi connection much if at all. The performance hit to the handset is too great for regular usage. Certainly with iPhone, the largest selling dual-mode device on the market, most people tend to use the EDGE data connection rather than Wi-Fi.

Second, there is no session mobility for non-UMA devices. Start surfing on the Wi-Fi connection, and if you walk out the door to GSM, that connection is lost. Wi-Fi and GSM are typically completely different subsystems on a non-UMA device. Of course with UMA, there is full session mobility for voice, data and IMS applications between Wi-Fi and the GSM network.

Third, because Wi-Fi is typically bolted onto a non-UMA device for basic data services, the Wi-Fi sub-system is not optimized for a mobile device. This was a common problem for the first UMA-enabled handsets. The Wi-Fi subsystems were simply ported from laptops and behaved like they were running on (relatively) power in-sensitive devices like PCs rather than on handsets.

Companies like NXP have invested tremendous resources in optimizing Wi-Fi (radio, stacks) to be voice-centric rather than laptop/PC centric. This optimization has paid off well, as the performance of their t409 product achieves 8 hours of talk time in Wi-Fi, according to one analyst.

Many see dual-mode devices as the next growth opportunity for Wi-Fi. This is certainly true. But there is a big difference between non-UMA and UMA-enabled devices.

Linksys joins in UMA-enabled ATA market

As reported on-line by Engadget through FCC filing, Linksys has developed an analog terminal adaptor (ATA) based on UMA technology for T-Mobile US.

UMA is fundamentally about FMS and enabling the mobile operator to deliver services over the public internet. With this new Linksys product, T-Mobile is now able to offer a fixed line VoIP service in the home similar to what Vonage and others deliver.

Why would T-Mobile do this when they have a perfectly good dual-mode handset service already available? It’s one more tool to accelerate FMS. In our household, my wife doesn’t particularly like walking around with her mobile phone stuck to her ear. It puts a kink in her neck.

However, our larger Panasonic cordless/DECT phone, connected to the incumbent fixed line provider, is more ergonomically pleasing. The idea is that we would port our fixed line number to T-Mobile who would provide us the ATA, and our fixed services would come from T-Mobile over our existing broadband network. Now T-Mobile can capture our entire in home voice usage, from both mobiles as well as the fixed line, through this terminal adaptor.

This let's mobile operators offer a Vonage-like service.

Note that this joins the already available Motorola RSG-3500 available from the Connected Homes Group.

We’ve said it before, we’ll say it again: UMA is really a ‘universal’ access technology for delivering any and all mobile services over IP; dual-mode phones, femtocells, terminal adaptors,... UMA let’s mobile operators harness the cost and performance advantages of IP to accelerate FMS.