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Dual mode phone trends update 3

I last looked at dual mode phone certifications on the Wi-Fi Alliance website almost a year ago.

Here’s what has happened since, through the first three quarters of 2009:
Wi-Fi Alliance Dual-Mode Phone Certifications 2005-2009

There are still no certifications for 802.11 draft n, and almost none for 802.11a.

Here’s another breakdown, by manufacturer and year. Click on the chart to get a bigger image. This shows that the Wi-Fi enthusiasts have been pretty constant over the years: Nokia, HTC, Motorola and Samsung. Then more recently SonyEricsson and LG. Note that the 2009 figures are only through Q3, so the growth is even more impressive than it seems from this chart.
Wi-Fi Alliance Dual-Mode Phone Certifications 2005-2009 by OEM

The all-time champion is Samsung, with a total of 84 phone models certified for Wi-Fi, followed by Nokia with 68, then HTC with 54. This changes if you look just at smartphones, where Nokia has 61 total certifications to HTC’s 34 and Samsung’s 29.

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Femtocell pricing chutzpah

It’s like buying an airplane ticket then getting charged extra to get on the plane.

The cellular companies want you to buy cellular service then pay extra to get signal coverage. Gizmodo has a coolly reasoned analysis.

AT&T Wireless is doing the standard telco thing here, conflating pricing for different services. It is sweetening the monthly charge option for femtocells by offering unlimited calling. A more honest pricing scheme would be to provide femtocells free to anybody who has coverage problem, and to offer the femtocell/unlimited calling option as a separate product. Come to think of it, this is probably how AT&T really plans for it to work: if a customer calls to cancel service because of poor coverage, I expect AT&T will offer a free femtocell as a retention incentive.

It is ironic that this issue is coming up at the same time as the wireless carriers are up in arms about the FCC’s new network neutrality initiative. Now that smartphones all have Wi-Fi, if the handsets were truly open we could use our home Wi-Fi signal to get data and voice services from alternative providers when we were at home. No need for femtocells. (T-Mobile@Home is a closed-network version of this.)

Presumably something like this is on the roadmap for Google Voice, which is one of the scenarios that causes the MNOs to fight network neutrality tooth and nail.

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VoIP on the cellular data channel

In a recent letter to the FCC, AT&T said that it had no objection to VoIP applications on the iPhone that communicate over the Wi-Fi connection. It furthermore said:

Consistent with this approach, we plan to take a fresh look at possibly authorizing VoIP capabilities on the iPhone for use on AT&T’s 3G network.

So why would anybody want to do VoIP on the cellular data channel, when there is a cellular voice channel already? Wouldn’t voice on the data channel cost more? And since the voice channel is optimized for voice and the data channel isn’t, wouldn’t voice on the data channel sound even worse than cellular voice already does?

Let’s look at the “why bother?” question first. There are actually at least four reasons you might want to do voice on the cellular data channel:

  1. To save money. If your voice plan has some expensive types of call (for example international calls) you may want to use VoIP on the data channel for toll by-pass. The alternative to this is to use the voice channel to call a local access number for an international toll by-pass service (like RebTel.)
  2. To get better sound quality: the cellular voice codecs are very low bandwidth and sound horrible. You can choose which codec to run over the data network and even go wideband. At IT Expo West a couple of weeks ago David Frankel of ZipDX demoed a wideband voice call on his laptop going through a Sprint Wireless Data Card. The audio quality was excellent.
  3. To get additional service features: companies like DiVitas offer roaming between the cellular and Wi-Fi networks that makes your cell phone act as an extension behind your corporate PBX. All these solutions currently use the cellular voice channel when out of Wi-Fi range, but if they were to go to the data channel they could offer wideband codecs and other differentiating features.
  4. For cases where there is no voice channel. In the example of David Frankel’s demo, the wireless data card doesn’t offer a voice channel, so VoIP on the data channel is the only option for a voice connection.

Moving on to the issue of cost, an iPhone unlimited data plan is $30 per month. “Unlimited” is AT&T’s euphemism for “limited to 5GB per month,” but translated to voice that’s a lot of minutes: even with IP packet overhead the bit-rate of compressed HD voice is going to be around 50K bits per second, which works out to about 13,000 minutes in 5GB. So using it for voice is unlikely to increase your bill. On the other hand, many voice plans are already effectively unlimited, what with rollover minutes, friend and family minutes, night and weekend minutes and whatnot, and you can’t get a phone without a voice plan. So for normal (non-international) use voice on the data channel is not going to reduce your bill, but it is unlikely to increase it, either.

Finally we come to the issue of whether voice sounds better on the voice channel or the data channel. The answer is, it depends on several factors, primarily the codec and the network QoS. With VoIP you can radically improve the sound quality of a call by using a wideband codec, but do impairments on the data channel nullify this benefit?

Technically, the answer is yes. The cellular data channel is not engineered for low latency. Variable delays are introduced by network routing decisions and by router queuing decisions. Latencies in the hundreds of milliseconds are not unusual. This will change with the advent of LTE, where the latencies will be of the order of 10 milliseconds. The available bandwidth is also highly variable, in contrast to the fixed bandwidth allocation of the voice channel. It can sometimes drop below what is needed for voice with even an aggressive variable rate codec.

In practice VoIP on the cellular data channel can sometimes sound much better than regular cellular voice. I mentioned above David Frankel’s demo at IT Expo West. I performed a similar experiment this morning with Michael Graves, with similarly good results. I was on a Polycom desk phone, Michael used Eyebeam on a laptop, and the codec was G.722. The latency on this call was appreciable – I estimated it at around 1 second round trip. There was also some packet loss – not bad for me, but it caused a sub-par experience for Michael. Earlier this week at Jeff Pulver’s HD Connect conference in New York, researchers from Qualcomm demoed a handset running on the Verizon network using EVRC-WB, transcoding to G.722 on Polycom and Gigaset phones in their lab in San Diego. The sound quality was excellent, but the latency was very high – I estimated it at around two seconds round trip.

The ITU addresses latency (delay) in Recommendation G.114. Delay is a problem because normal conversation depends on turn taking. Most people insert pauses of up to about 400 ms as they talk. If nobody else speaks during a pause, they continue. This means that if the one-way delay on a phone conversation is greater than 200 ms, the talker doesn’t hear an interruption within the 400 ms break, and starts talking again, causing frustrating collisions.
The ITU E-Model for call quality identifies a threshold at about 170 ms one-way at which latency becomes a problem. The E-Model also tells us that increasing latency amplifies other impairments – notably echo, which can be severe at low latencies without being a problem, but at high latencies even relatively quiet echo can severely disrupt a talker.

Some people may be able to handle long latencies better than others. Michael observed that he can get used to high latency echo after a few minutes of conversation.

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Nokia no longer the only VoWi-Fi friendly phone maker

Until now, Nokia has been top of the heap in the category of VoIP-friendliness. When I spoke with Richard Watson, CTO of DiVitas, last year in the course of my test drive of the DiVitas system, he pointed out that dual-mode phones are not normally VoIP-friendly. At that time the only phone he recommended was the Nokia E71. There are several reasons for this, primarily the treatment of the voice path and the ease of integration of the VoIP software with the built-in phone software user interfaces. Since then, DiVitas has been working closely with Samsung, and now Richard says several Samsung phones are well suited to Voice over Wi-Fi. Let’s hope this shakes the other phone OEMs loose and gets them working on improving Voice over Wi-Fi performance.

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Dual-mode technology maturing

The Rethink Wireless newsletter is always worth reading. An article in today’s edition says that according to ABI dual mode handset shipments are on track to double from 2008 to 2010, and more than double from 2009-2011 (144 million units to 300 million units).

Rethink’s Matt Lewis cites improved performance and usability as driving forces, plus a change in the attitudes of carriers towards hot-spots. Wireless network operators now often have captive Wi-Fi networks and can use them to offload their cellular networks.

The upshot is a prediction of 300 million dual mode handsets to ship in 2011: 100% of the smartphone market plus high end feature phones.

The attach rate of Wi-Fi will continue to grow. By 2011 the effects of Bluetooth 3.0 will be kicking in, pushing Wi-Fi attachment towards 100% in camera phones and music phones in ensuing years.

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Skype for iPhone

Well, that last post on the likely deficiencies of VoIP on iPhones may turn out to have been overly pessimistic. It looks as though Hell is beginning to freeze over. Skype is now running on iPhones over the Wi-Fi connection, and for a new release it’s running relatively well. AT&T deserves props for letting it happen – unlike T-Mobile, which isn’t letting it happen and therefore deserves whatever the opposite of props is.

6 hours after it was released Skype became the highest-volume download on Apple’s AppStore. In keeping with Skype’s reputation for ease of use, it downloads and installs with no problems, though as one expects with first revisions it has some bugs.

My brief experience with it has included several crashes – twice when I hung up a call and once when a calendar alarm went off in the middle of a call. Another interesting quirk is that when I called a friend on a PC Skype client from my iPhone, I heard him answer twice, about 3 seconds apart. Presumably a revision will be out soon to fix these problems.

Other quirky behaviour is a by-product of the iPhone architecture rather than bugs, and will have to be fixed with changes to the way the iPhone works. The biggest issue of this kind is that it is relatively hard to receive calls, since the Skype application has to be running in the foreground to receive a call. This is because the iPhone architecture preserves battery life by not allowing programs to run in the background.

Similar system design characteristics mean that when a cellular call comes in a Skype call in progress is instantly bumped off rather than offering the usual call waiting options. I couldn’t get my Bluetooth headset to work with Skype, so either it can’t be done, or the method to do it doesn’t reach Skype’s exemplary ease of use standards.

Now for the good news. It’s free. It’s free to call from anywhere in the world to anywhere in the world. And the sound quality is very good for a cell phone, even though the codec is only G.729. I expect future revisions to add SILK wideband audio support to deliver sound quality better than anything ever heard on a cell phone before. The chat works beautifully, and it is synchronized with the chat window on your PC, so everything typed by either party appears on both your iPhone and PC screen, with less than a second of lag.

After a half-hour Skype to Skype conversation on the iPhone I looked at my AT&T bill. No voice minutes and no data minutes had been charged, so there appear to be no gotchas in that department. A friend used an iPod Touch to make Skype Wi-Fi calls from an airport hot-spot in Germany – he reports the call quality was fine.

The New York Times review is here

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AT&T to deploy Voice over Wi-Fi on iPhones

Don’t get too excited by Apple’s announcement of a Voice over IP service on the iPhone 3.0. It strains credulity that AT&T would open up the iPhone to work on third party VoIP networks, so presumably the iPhone’s VoIP service will be locked down to AT&T.

AT&T has a large network of Wi-Fi hotspots where iPhone users can get free Wi-Fi service. The iPhone VoIP announcement indicates that AT&T may be rolling out voice over Wi-Fi service for the iPhone. It will probably be SIP, rather than UMA, the technology that T-Mobile uses for this type of service. It is likely to be based on some flavor of IMS, especially since AT&T has recently been rumored to be spinning up its IMS efforts for its U-verse service, which happens to include VoIP. AT&T is talking about a June launch.

An advantage of the SIP flavor of Voice over Wi-Fi is that unlike UMA it can theoretically negotiate any codec, allowing HD Voice conversations between subscribers when they are both on Wi-Fi; wouldn’t that be great? The reference to the “Voice over IP service” in the announcement is too cryptic to determine what’s involved. It may not even include seamless roaming of a call between the cellular and Wi-Fi networks (VCC).

AT&T has several Wi-Fi smartphones in addition to the iPhone. They are mostly based on Windows Mobile, so they can probably be enabled for this service with a software download. The same goes for Blackberries. Actually, RIM may be ahead of the game, since it already has FMC products in the field with T-Mobile, albeit on UMA rather than SIP, while Windows Mobile phones are generally ill-suited to VoIP.

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DiVitas partners with Avaya

Last week Avaya announced that it has chosen DiVitas as its preferred partner for mobile unified communications (UC). The companies will do joint marketing and cross-training of their sales forces in a reference sale mode. This is huge for DiVitas because it opens Avaya’s distribution channel to it. According to Phil Klotzkin, Avaya’s senior manager for UC, this channel supplies 20% of the business phone systems world-wide.

The DiVitas solution plugs a small but important gap in Avaya’s product line. Avaya already has a mobile unified communications solution, called one-X Mobile.

One-X Mobile extends PBX features to cell phones, notably the ability to give out a single number that rings on both your cell phone and your desk phone; the ability to do PBX-related actions like 4 digit dialing and transfers; visual voicemail; and the ability to move a call in progress between the cell-phone and the desk phone.

The DiVitas product offers a comparable solution set, but goes beyond one-X Mobile with Wi-Fi voice and a range of social networking features including IM and Presence. Because it uses Wi-Fi, the DiVitas solution requires a dual-mode handset. Virtually all new smartphones are dual-mode, but with the exception of Nokia’s Eseries and Nseries, few of them are well suited to voice over Wi-Fi. One-X Mobile uses the cellular voice channel rather than Wi-Fi, so it runs on a wide variety of phones.

For IM related features both DiVitas and Avaya’s desktop Integrated Presence Server use open source Jabber software. The two will be integrated with each other by the end of the year.

DiVitas/Avaya system diagram

For now the DiVitas handset software (client) is not integrated with the one-X Mobile handset software – the customer will choose one or the other for each user. The DiVitas client and the one-X Mobile client will each retain their different look and feel, and the one-X Mobile client will continue to run on single-mode phones and the DiVitas client on dual-mode.

In a recent interview, Klotzkin said that one-X Mobile is sufficient for most customers, but that there are a few for which dual-mode functionality is essential. Partnering with DiVitas enables Avaya to satisfy those customer needs. One such customer is CSX, the freight company. Some of its far-flung operations are in areas with no cellular coverage; Wi-Fi solves this problem. Avaya has been working with CSX on dual-mode solutions since 2004, when Avaya, Motorola and Proxim introduced the very first dual-mode system.

According to Vivek Khuller, CEO of DiVitas, “CSX has been working with Avaya since the earliest days of dual-mode telephony, and they are finally satisfied. It’s an important accomplishment for both our companies.”

Because the DiVitas solution uses smart-phones CSX gets a useful side benefit, namely that it can run proprietary application software on the phones, eliminating the need for its employees to carry a laptop. The other side benefit is that even in areas of cellular coverage the Wi-Fi connection can be used to save on cellular minutes.

So everybody gains. Avaya plugs a troublesome gap in its product line; DiVitas gets an excellent distribution channel; the Avaya channel adds a fully supported best-of-breed solution to its portfolio; and end users get the familiarity of Avaya with the handset technology of Nokia and the DiVitas software that weaves them together into a user-friendly package.

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Skype’s SILK codec available royalty free to third parties

I wrote earlier about the need for royalty-free wideband codecs, and about a conversation with Jonathan Christensen about SILK, Skype’s new super-wideband codec.

This week Jonathan announced that Skype is releasing an SDK to let third parties integrate SILK with their products, and distribute it royalty free. This is very good news. It comes on top of Skype’s announcement that Nokia is putting the Skype client on some of its high end phones. If the Nokia deal includes SILK, and the platform exposes SILK to third party applications on the phones, SILK will quickly become the most widely used wideband codec for SIP as well as the most widely used wideband codec, period. That is, if the Nokia deal stands.

Polycom has been leading the wideband codec charge on deskphones, and it already co-brands a phone with Skype. It would make sense for Polycom to add SILK to its entire line of IP phones.

For network applications like voice, Metcalfe’s Law is like gravity. Skype has over 400 million users. If the royalty-free license has no catches, the wideband codec debate is history, at least until LTE brings AMR-WB to mass-market cell phones.

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Sharing Wi-Fi 2 – Atheros turns a cellphone into an access point

There are several smartphone applications that allow a cell phone to act as a wireless WAN router and Wi-Fi access point, creating a wireless LAN with Internet access. For the (jailbroken) iPhone there’s PDAnet, for Windows Mobile there’s WM Wi-Fi Router and for Symbian there’s Walking HotSpot and JoikuSpot. Now Atheros has proposed to bake this functionality into their low power Wi-Fi chipset.

An idea that is as patent jargon goes “obvious to one skilled in the art,” can sometimes have obvious handicaps to one experienced in the industry. While exposing a broadband wireless data connection through a smartphone’s Wi-Fi radio is massively useful to consumers, it is unlikely to appeal to network service providers, who would prefer you to buy a wireless data card (and an additional service subscription) for your laptop rather than to simply use the wireless data connection that you are already paying for on your phone.

It will be interesting to see where this goes. I will be stunned if Atheros’ implementation appears on any phone subsidized by (or even distributed by) a wireless carrier, until they can figure out a way to charge extra for it. As Tim Wu says in his Wireless Carterfone paper (the Wireless Carterfone concept was promoted by Skype, and rejected by the FCC last April):

carriers are in a position to exercise strong control over the design of mobile equipment. They have used that power to force equipment developers to omit or cripple many consumer-friendly features.

The billing issue may not be that intractable. Closely related models already exist. You can get routers from Cisco and other vendors that have a slot for a wireless WAN card, and the service providers have subscription plans for them. More similarly, this could be viewed as a kind of “tethering” But tethering only lets one PC at a time access the wireless WAN connection – unless that PC happens to support My Wi-Fi.

Update: Marvell has announced a similar capability for its 88W8688 chip.