Posted on

Wideband audio conferencing bridge

Skype lets you do audio conferencing with wideband codecs, and a service called Vapps High Definition Conferencing does the same thing for non-Skype VoIP calls.

Now other VoIP providers can offer wideband conferencing too. A company called Wyde Voice sells an all-IP conferencing platform that natively uses wideband codecs. The Wyde platform uses the iSAC codec from GIPS, so anybody calling in from a soft phone like the Gismo5 client, or the Google, AOL or Yahoo VoIP clients can enjoy a conference in wideband. If one of the participants in the call is using a narrow-band codec, the Wyde device up-samples the signal to wideband quality for mixing.

I have always been an enthusiastic proponent of wideband audio – it is one of the major potential advantages of VoIP over circuit switched telephony. Circuit switched calls are encoded with G.711, which yields 12 bits of effective dynamic range and a maximum frequency of about 3.5KHz. Human speech has harmonics even above 10KHz, which is why it is hard to tell the difference between an “F” and an “S” over the phone. The G.711 codec places an absolute limit on the sound quality of a regular phone call. A VoIP phone call can use a wideband codec, with whatever dynamic range and frequency range you want. There are several of them, commonly with a sample size of 16 bits and a sampling rate of 16KHz which captures a maximum audio frequency of 8KHz. When you have a good enough connection Skype uses a wideband codec by default, which is why it can sound better than “toll quality” (if you aren’t limited by your loudspeaker and microphone.)

Unfortunately, for the non-Skype world there’s a chicken and egg problem – almost no phones support wideband codecs, so the carriers aren’t motivated to support them either. Worse, any VoIP call that traverses the PSTN at any point is converted to G.711, losing the wideband frequencies. Worse yet, to cut costs most carrier implementations of VoIP use a bandwidth-saving codec that intrinsically delivers inferior sound quality to G.711; for example, last I heard Vonage was using G.729A.

As VoIP matures, and more and more calls are IP end-to-end through VoIP peering and ENUM arrangements (what Gizmo5 calls “back-door dialing”) wideband codecs will become more pervasive and our conversations will become clearer. The Wyde announcement is a step towards that world.

Posted on

White Space update from TV Technology.com

Robin Berger of TVTechnology.com has written a good summary of the current (9th April 2008) state of White Spaces. She details the status of device testing at the OET and the recent proposal by Google on spectrum sensing, noting that Google’s embracing of geolocation puts them at odds with the rest of the Wireless Innovation Alliance.

She lists the main advocacy groups on each side of the issue, and summarizes their positions. Among the people apparently interviewed for the article are Stu Overby, Motorola’s senior director of Global Spectrum Strategy, Ed Thomas of the White Spaces Coalition and Ahren Hartman, Shure’s director of Platform Engineering. Also quoted in the article are David Donovan of the MSTV and statements from the NAB and the Broadway League, which is interested in wireless microphones.

In the discussion of the testing, the article covers the wireless microphone issue in depth, with an interview with Ahren Hartman.

Posted on

White Space update

The forthcoming transition to digital TV transmissions will free up about half the spectrum currently allocated to TV broadcasters. This freed-up spectrum was the subject of the FCC’s just-concluded 700MHz Auction, which yielded about $20 billion in license fees to the government. The fate of the other half of the TV spectrum, the part that will remain assigned to TV broadcasts after the digital transition, remains in contention.

This spectrum will be shared by licensed TV broadcast channels and wireless microphones, but even so much of it will remain mostly unused. These chunks of spectrum left idle by their licensees are called “White Spaces.” The advent of “spectrum sensing” radio technology means that it is now theoretically possible for transmitters to identify and use White Spaces without interfering with the licensed use of the spectrum.

The FCC has issued a Notice of Proposed Rulemaking and a First Report and Order to explore whether this is a good idea, and if so, how to handle it.

The potential users of the White Spaces have formed roughly two camps, those who see it best suited for fixed broadband access (similar to the first version of WiMAX), and those who see it as also suited for “personal/portable” applications (similar to Wi-Fi).

Google, along with Microsoft and some other computer industry companies, advocates the personal/portable use. The FCC’s Office of Engineering and Technology (OET) is currently lab-testing some devices from Microsoft and others to see if their spectrum-sensing capabilities are adequate to address the concerns of the broadcast industry, which fears that personal/portable use will cause interference.

Google filed an ex-parte letter with the FCC on March 24th, weighing in on the White Spaces issue. The letter is well worth reading. It concedes that in the introductory phases it makes sense to supplement spectrum sensing with other technologies, like geo-location databases and beacons. The letter asserts that these additional measures render moot the current squabble over a malfunction in the devices in the first round of FCC testing, and that the real-world data gathered in this introductory phase would give the FCC confidence ultimately to repeal the supplemental measures, and perhaps to extend open spectrum-sensing uses to the entire radio spectrum, leading to a nirvana of effectively unlimited bandwidth for everybody.

The kicker is in the penultimate paragraph, where Google recycles an earlier proposal it made for the 700MHz spectrum auction, suggesting a real-time ongoing “dynamic auction” of bandwidth. Google now suggests applying this dynamic auction idea to the white spaces:

For each available spectrum band, the licensee could bestow the right to transmit an amount of power for a unit of time, with the total amount of power in any location being limited to a specified cap. This cap would be enforced by measurements made by the communications devices. For channel capacity efficiency reasons, bands should be allocated in as large chunks as possible. The airwaves auction would be managed via the Internet by a central clearinghouse.

Current expectations are for spectrum-sensing use of the whites spaces to be unlicensed (free, like Wi-Fi). Now Google appears to be proposing “sub-licensed” rather than unlicensed spectrum use. The word “auction” implies that this could be a revenue producer for TV broadcast licensees, who received their licenses free from the government. This is a very different situation than the original context of the dynamic auction proposal, which applied to spectrum for which licensees paid $20 billion. Depending how it is implemented, it could fulfill the telcos’ dream of directly charging content providers for bandwidth on a consumer’s Internet access link, a dream that Google has opposed in the network neutrality wars. Google may ultimately regret opening the door to this one, even though it presumably sees itself cashing in as the ideal candidate to operate the “central clearinghouse.”

Update April 10th: Interesting related posts from Michael Marcus and Sascha Meinrath.

Posted on

FCC 700 MHz “Open Platform” Auction Completed

It took a while, and 261 rounds of bidding, but its over. Click here for the write-up from Wired.

The attractive thing about the 700 MHz spectrum that was freed up by the move to digital TV broadcasting is that transmissions at these frequencies pass through walls. The unusual thing about the “C Block” of this spectrum is that the FCC attached “open access” conditions to the license. This was at the behest of the computer industry, spearheaded by Google, who may even have made a bid on this block. But as the Wired story points out, Google had already won their victory with the imposition of the open access rules – winning the spectrum would have been more of a headache for them than losing it.

Don’t confuse the spectrum licensed in this auction with the White Spaces spectrum. The White Spaces spectrum is the spectrum that the TV broadcasters retained for their transition to digital transmissions in February 2009. The White Spaces issue is still unresolved by the FCC. The FCC is deliberating over whether to allow unlicensed use of the digital TV spectrum when it is not being used by a TV broadcast (hence “White Spaces.”) This use depends on effective functioning of “cognitive radio,” which lets transmitters sense by listening (and other means) when spectrum is available for use. If the FCC allows it, they still have to decide whether to allow only fixed broadband replacement like 802.22, or to allow “Personal and Portable” use as well.

Posted on

What is Enterprise FMC?

“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean — neither more nor less.”

The term “Fixed Mobile Convergence” is an umbrella for so many different things that it has become almost meaningless when used without elaboration. Here’s how it started out, in the 2004 press release announcing the formation of the FMCA:

Fixed-Mobile Convergence is a transition point in the telecommunications industry that will finally remove the distinctions between fixed and mobile networks, providing a superior experience to customers by creating seamless services using a combination of fixed broadband and local access wireless technologies to meet their needs in homes, offices, other buildings and on the go.

In this definition “Fixed broadband” means a connection to the Internet, like DSL, cable or T1. “Local access wireless” means Wi-Fi or something like it. BT’s initial FMC service actually used Bluetooth rather than Wi-Fi for the local access wireless. The advent of picocells and femtocells means that the local access wireless can be cellular radio technology.

The term “seamless services” in the quotation above is ambiguous. When talking about FMC, the word “seamless” usually refers to “seamless handover,” which means that a call in progress can move from the mobile (cellular) network to the fixed network on the same phone without interruption, as described in one of the FMCA specification documents:

Seamless is defined as there being no perceptible break in voice or data transmission due to handover (from the calling party or the called party”s perspective).

The term “Seamless services” sometimes means service equivalence across any termination point, fixed or mobile, so for example, dialing plans are identical and no change in dialed digits is required on a desk phone versus a mobile. A less ambiguous term for this might be “Network Agnostic Services.” To do it properly is very difficult, for example I have not been able to track down an Enterprise FMC system that offers SMS on the desktop phone.

The FMCA is a carrier organization, mainly oriented to consumer services. Enterprise phone systems are different. When Avaya announced its “Fixed Mobile Convergence” initiative in 2005, it was using a different definition. What Avaya and other PBX manufacturers were calling FMC was the ability for a PBX to treat a cell phone as an extension, and the ability for a cell phone to behave like a PBX extension phone:

Extension to Cellular technology: software seamlessly bridges office phone services to mobile devices, permitting the use of just one phone number and one voice mailbox.
Client software extends the capabilities of the PBX to a mobile smartphone – creating a virtual desk extension. This software runs on Nokia Series 60 phones and works in conjunction with Extension to Cellular.

In other words, this new definition of FMC didn’t include local access wireless and it didn’t include fixed broadband technology. The only defining characteristic it shared with the previous definition was seamless services, albeit without seamless handover.

“The question is,” said Alice, “whether you can make words mean so many different things.”
“The question is,” said Humpty Dumpty, “which is to be master – that’s all.”

We can regain mastery here by breaking out the features of the various definitions of Enterprise FMC, giving them names, and using those terms to describe the various solutions on offer. Here’s a first cut:

Session Redirection
This simply means moving a call in progress from the cell phone to desk phone or vice-versa, in much the same way as you might transfer a call from one extension to another. For example, you are in your car on the way to work, listening in on a conference call on your cell phone. You walk in to the office, sit down, and redirect the call (session) to your desk phone. Depending on the implementation, you might control the process from your cell phone, your desk phone or your PC, using touch-tones or something more user-friendly.

PBX Mobility
This is what the Avaya press release called “Extension to cellular,” and some other vendors call “PBX Extension.” You program the cell phone number into the PBX (or third party PBX Mobility device – see the paragraph below headed “PBX Agnostic”), and then when somebody calls your office number, the PBX dials your cell phone over the PSTN and bridges the call. The PBX treats the cell phone as though it is an analog extension, so you can invoke PBX features like hold and transfer by touch-tone commands. This means that you can use any cell phone and any carrier (see the paragraphs below headed “Handset Agnostic” and “Carrier Agnostic”.)

Treating the mobile phone as an analog extension to the PBX opens up several more possibilities. Various flavors of this service might include features like Single Number, Simultaneous Ringing and Single Voicemail.

“Single Number” means that the mobile phone and the desk phone share an extension number. So you only need to give out one phone number to receive calls on either your mobile or desk phone. But bear in mind that your cell phone probably still has its own number – it’s just that you don’t give it out to anybody. In order to make business calls from your cell phone, you dial an access number at your office, get a new dial tone, and then dial the destination number. This allows you to take advantage of corporate least-cost-routing, and it shows your office number on the Caller ID display of the person you are calling.

Single Voicemail is the option to use the corporate voice mail rather than the cell phone’s voice mail. This only works on calls made to your office number.

“Simultaneous Ringing” means that when somebody calls your office number, your desk phone and your mobile phone ring simultaneously.

When your cell phone receives a call made to your office number, the Caller ID display would normally show your office as the caller, since the call is routed though the PBX. When the client software on the cell phone can pre-empt the built-in phone software (depends on the handset and the client software vendor) this Caller ID is suppressed and the mobility controller passes the correct calling number and name to the client software on the handset using the cellular data channel. Alternatively, depending on your PBX and carrier, the system may be able to insert the Caller ID of the person calling you into the regular Caller ID notification (Caller ID spoofing). This will show the ‘correct’ Caller ID even on the built-in handset interface.

Client Software
PBX Mobility on a regular cell phone is not particularly user friendly, what with the touch-tone interface and the access number prefixing. With a smart phone things get a lot better. The definition of a Smart Phone is that it can run third-party software. If you happen to have a smart phone, and it is a model supported by your Enterprise FMC system, you will be able to run a “Client application” that puts a friendly user interface on the PBX Mobility features, allowing easy use of PBX features like 4 digit dialing to other extensions.

If the phone supports it, well written client applications can completely hide the native phone user interface. Otherwise users will have two different screens from which to dial calls – the built-in one and the client application.

RIM has built PBX signaling features into its handsets running firmware version 4.2.1 or higher. This means that Blackberries can access PBX features through menus rather than touch-tones, even without add-on client software.

Dual-mode Phone Support
A dual-mode phone is a cell phone that also has Wi-Fi. The Wi-Fi can be for data only (like the iPhone), for voice only (like the Nokia 6086), or for both.

There are two main categories of wireless extensions to PBXs: those that work over Wi-Fi (VoWLAN, or VoWi-Fi), and those that use other radio technologies like DECT. Client software can make a dual-mode smart phone act as a Wi-Fi extension to the PBX. This gives the handset a split personality: a regular cell phone and a VoIP PBX extension, each having its own phone number. These two personalities can be well integrated, completely separate or something in between. Session Redirection as described above moves the call between devices; with a dual-mode phone, you can do Session Redirection between the two networks, keeping the call on the same handset.

Well integrated dual-mode user interfaces are sometimes described as “Network Agnostic” (see below).

Session Continuity
Dual mode handset clients can completely hide their split personality, taking the onus of Session Redirection off the user, and dealing with it automatically. When the system senses that you have walked into Wi-Fi coverage it moves the call over onto the VoWi-Fi side. When you move out of Wi-Fi coverage it moves the call back to the cellular side. This is also sometimes called “seamless handover” or “automatic handover.” To do it imperceptibly to the user is technically challenging. This automatic, seamless flavor of Session Redirection is often termed VCC, or Voice Call Continuity. The term VCC has the disadvantage that it specifically mentions voice, while FMC systems are evolving towards multimedia sessions where voice is only one of the elements. So a better term might be Session Continuity.

Session Continuity requires client software support in the handset, either with built-in VCC client software, or (more commonly in Enterprise FMC) as a part of the client software from the Enterprise FMC system vendor.

Mobility Controller
VCC is a term lifted from the IMS (IP Multimedia Subsystem) specifications published by the international bodies concerned with standardizing cellular technologies. In IMS terminology, VCC is done by software called the “Call Continuity Control Function,” or CCCF.

Session Redirection and Session Continuity require a device in the network that routes and reroutes the call over either the fixed or mobile network as needed (that is to say, something that embodies the CCCF.) There are many terms for this device, and each of these terms can also mean something else. Also the various devices that incorporate Session Redirection or Session Continuity usually also do other things. These devices have names like “Mobility Server,” “Mobility Controller,” “Mobility Router,” “Mobility Appliance” or “Mobility Gateway.”

Carrier FMC and Enterprise FMC
The path of a call transits both the service provider network and the enterprise network, and the Mobility Controller can be located just about anywhere on that path. If it is in the service provider network we call the system Carrier-based FMC, if in the enterprise network, Enterprise FMC. This is the defining characteristic of Enterprise FMC.

Most Carrier-based FMC is aimed at the consumer market, but there are some implementations that support enterprise features like PBX Mobility. Carrier-based FMC can support PBX Mobility either by installing a PBX Mobility control device near the PBX in the enterprise network (the approach taken by Tango Networks), or perhaps by offering the PBX functionality as a network service (Centrex), the approach taken by Sotto Wireless.

Carrier FMC normally uses one of two technologies to implement Session Continuity, VCC or UMA (Unlicensed Mobile Access, also known as GAN, for Generic Access Network). UMA is an older technology, which transports GSM packets through the IP network; the handset uses the same GSM signaling stack for Wi-Fi calls as for cellular. With the predicted conversion of the carrier networks to all-IP, UMA has been superseded by VCC, which uses SIP signaling.

Handset Agnostic
We mentioned above that basic PBX Mobility can work with any cellular handset. At the other extreme, Carrier FMC usually only works with particular handsets. For example the T-Mobile@Home service works with only three handsets, one each from Nokia, Motorola and RIM. Client software for Enterprise FMC almost always works on phones that run the Windows Mobile or S60 operating systems, particularly the HTC phones and the Nokia Eseries respectively. Other smartphone operating systems that may be supported include Linux and RIM, and in the future OSX and Android. Handset agnosticism is a major selling point. A handset agnostic system is more attractive to Enterprise FMC customers than one that limits the choice of handsets.

Carrier Agnostic
A system with the Mobility Controller in the enterprise network can work with any carrier, provided the carrier will allow the phones to connect to their network. The benefit of this is that the customer gets a wide selection of phones, and the FMC system will work on employees’ personal phones, even when those phones are on an assortment of carriers.

A system with the Mobility Controller in the carrier network is not carrier agnostic from the point of view of the customer. They have to buy service from that carrier.

PBX Agnostic
Each of the PBX vendors offers a mobility capability. Some developed it internally. Some, like Cisco or Avaya, bought a third party developer, and some license their offering from a company like Telepo , Comdasys or Counterpath (formerly FirstHand). There is another set of vendors that offers Enterprise FMC that works with any PBX, for example DiVitas, Agito, Tango and RIM. This is beneficial to both large and small customers. Large customers may have PBXes from multiple vendors, yet still wish to roll out a unified FMC solution. Small customers appreciate having a choice of supplier, rather than being tied to their PBX vendor.

Network Agnostic Interface
Some vendors use this term to mean that all features are available through a uniform user interface in both cellular and Wi-Fi networks. This means that the user should not be able to perceive which network is carrying their session on a dual-mode phone.

Conclusion
Agonizing over minute definitions is tedious, but when evaluating competing solutions it is essential to be able to recognize when two vendors use the same term in different ways, when they use different terms for the same feature, or when they describe a feature without giving it a name.

Posted on

Ask and ye shall receive

Ken Dulaney, Gartner VP distinguished analyst and general mobile device guru, told the crowd at the Gartner Mobile & Wireless Summit today that he still can’t recommend businesses adopt the iPhone — even with an SDK. Dulaney said that he recently wrote Apple a letter in which he outlined several things Apple would need to do with the iPhone before Gartner could change its mind about it. The directives included:
– Permit the device to be wiped remotely if lost or stolen
– Require strong passwords
– Stop using iTunes for syncing with a computer
– Implement full over-the-air sync for calendar and PIM

Jason Hiner, TechRepublic March 5th, 2008

On the same day Dulaney said this in Chicago, Phil Schiller of Apple was holding a news conference in Santa Clara granting some of these wishes, and many more:

  • Microsoft Exchange support with built-in ActiveSync.
  • Push email
  • Push calendar
  • Push contacts
  • Global address lists
  • Additional VPN types, including Cisco IPsec VPN
  • Two-factor authentication, certificates and identities
  • Enterprise-class Wi-Fi, with WPA2/802.1x
  • Tools to enforce security policies
  • Tools to help configure thousands of iPhones and set them up automatically
  • Remote device wiping

At the news conference Apple wheeled out several corporate endorsers: Genentech, Stanford University, Nike and Disney.

At first blush, the new enterprise-oriented capabilities of the iPhone appear to be an IT manager’s dream come true (though it will be a while before the dream is a reality.) Even this contrarian post concedes that it will make the iPhone more competitive with the Blackberry, while faulting Apple for not having a comprehensive enterprise strategy.

Apple is clearly serious about the enterprise smartphone market, and this strategy is sound. The business market supports price points that easily accommodate the iPhone, and this strategy spills over to the business PC market in two ways: today by acting as a door-opener for Mac sales, tomorrow by evolving the iPhone into a PC replacement for many users.

Posted on

iPhone 3G, SDK, enterprise orientation

UBS thinks that the 3G iPhone will be released mid-year. iLounge reports that the much-anticipated iPhone SDK will be delivered in June, at Apple’s Worldwide Developer Conference. A beta version will be released at an announcement event on March 6th.

There are several reports that Apple intends to target business users with the iPhone, competing with Blackberries, Nokia’s Eseries and Windows Mobile devices. Since the SDK reportedly will expose interfaces to the phone and Wi-Fi, developers of Wi-Fi soft-phones and enterprise Fixed-Mobile Convergence systems will presumably add iPhone support to their existing Symbian and Windows-supporting products. It remains to be seen how easy it will be for developers to actually get their software “officially” onto the iPhone. Apple can choose their degree of open-ness from a variety of options discussed here.

For Apple to aim at the business market makes a lot of sense. With the successful transition to Intel processors Macs already run Windows natively, and iPhones are supposedly making inroads among executives. According to ChangeWave, summarized here, the iPhone has a 5% share of corporate smartphones already, with astronomical ratings for satisfaction.

To make enterprise IT departments happy, though, Apple will have to make the iPhone more manageable; either by building in OMA DM like Nokia with the Eseries, or by letting third parties develop enterprise manageability clients using the iPhone SDK.

Competitors aren’t sitting still for this. The October 2007 announcement of “Microsoft System Center Mobile Device Manager” was a step forward for Windows Mobile in the enterprise. Microsoft is also leaking stories about how when Windows Mobile 7 is released in 2009 it is going to be more of a pleasure to use than the iPhone. It is conceivable, I suppose, but Microsoft’s track record on usability is pretty consistent. The fundamental part that they invariably seem to get wrong is instant response to user input.

Posted on

Bluetooth over Wi-Fi

The Bluetooth SIG put out a press release the other day saying that by mid-2009 a specification that includes Wi-Fi as an “alternate MAC/PHY” will be released.

This is the relevant part of the release:

What we’re doing is taking classic Bluetooth connections – using Bluetooth protocols, profiles, security and other architectural elements – and allowing it to jump on top of the already present 802.11 radio, when necessary, to send bulky entertainment data, faster. When the speed of 802.11 is overkill, the connection returns to normal operation on a Bluetooth radio for optimal power management and performance.

So this innovation specifies an interface above the Bluetooth MAC layer that enables Bluetooth session data to flow through a Wi-Fi radio instead of a Bluetooth one.

The press release says that the Alternate MAC/PHY will be used to do things like:

Wirelessly bulk synchronize music libraries between PC and MP3 player.
Bulk download photos to a printer or PC.
Send video files from camera or phone to computer or television.

But the new specification will only be useful in devices that already have both Wi-Fi and Bluetooth, and Wi-Fi can do these things without any assistance from Bluetooth. So the increment in value may be small; but Bluetooth can still bring something to the table. According to Wikipedia,

The Bluetooth Radio will still be used for device discovery, initial connection and profile configuration, however when lots of data needs to be sent, the high speed alternate MAC PHY’s will be used to transport the data.

It seems oddly limiting not to go the whole way, and enable Bluetooth applications to run on top of Wi-Fi even when there is no Bluetooth radio.

Posted on

Potential security vulnerability in some Wi-Fi handsets

George Ou of ZDNet reports that the 802.1X authentication techniques used on some Wi-Fi handsets may be vulnerable. The problem is that these handsets may not validate the certificate from the authentication server. This design choice speeds up roaming, but means that the handset could disclose user login credentials to a sophisticated, determined attacker. Ou suggests using WPA-PSK with a long password instead of 802.1X with these handsets.

Vocera’s documentation, which Ou references, has more depth on the performance trade-offs of various Wi-Fi security options.