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MIMO for handset Wi-Fi

I mentioned earlier that the Wi-Fi Alliance requires MIMO for 802.11n certification except for phones, which can be certified with a single stream. This waiver was for several reasons, including power, size and the difficulty of getting two spatially separated antennas into a handset. Atheros and Marvell appear to have overcome those difficulties; both have announced 2×2 Wi-Fi chips for handsets. Presumably TI and Broadcom will not be far behind.

The Atheros chip is called the AR6004. According to Rethink Wireless,

The AR6004 can use both the 2.4GHz and the 5GHz bands and is capable of real world speeds as high as 170Mbps. Yet the firm claims its chip consumes only 15% more power than the current AR6003, which delivers only 85Mbps. It will be available in sample quantities by the end of this quarter and in commercial quantities in the first quarter of next year.

The AR6004 appears to be designed for robust performance. It incorporates all the optional features of 802.11n intended to improve rate at range. Atheros brands this suite of features “Signal Sustain Technology.” The AR6004 is also designed to reduce the total solution footprint, by including on-chip power amplifiers and low-noise amplifiers. Historically on-chip CMOS power amplifiers have performed worse than external PAs using GaAs, but Atheros claims to have overcome this deficiency, prosaically branding its solution “Efficient Power Amplifier.”

The 88W8797 from Marvell uses external PAs and LNAs, but saves space a different way, by integrating Bluetooth and FM onto the chip. The data sheet on this chip doesn’t mention as many of the 802.11n robustness features as the Atheros one does, so it is unclear whether the chip supports LDPC, for example.

Both chips claim a maximum 300 Mbps data rate. Atheros translates this to an effective throughput of 170 Mbps.

Of course, these chips will be useful in devices other than handsets. They are perfect for tablets, where there is plenty of room for two antennas at the right separation.

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ISP Performance numbers from Netflix

Interesting numbers from the Netflix Tech Blog.

Several things jump out at me. First, cable is faster than DSL, and wireless is the slowest. Second, again no surprise, urban is faster than rural. But the big surprise to me is the Verizon number. They have spent a ton on FIOS, and according to Trefis about half of Verizon’s broadband customers are now on FiOS. So according to these numbers, even if we supposed that Verizon’s non-FiOS customers were getting a bandwidth of zero, the average bandwidth available to a FiOS customer appears to be less than 5 megabits per second.

Since FiOS is a very fast last mile, the bottleneck might be in the backhaul, or, more likely, in some bandwidth-throttling device. Whichever way you slice it, it’s hard to cast these numbers in a positive light for Verizon.

Netflix measurements of ISP bandwidth
Update January 31, 2011: This story in the St. Louis Business Journal says that the Charter, the ISP with the best showing in the Netflix measurements, is increasing its speed further, with no increase in price. This is good news. It is time that ISPs in the US started to compete on speed.

Contemplating the graphs, the lines appear to cluster to some extent in three bands, centered on 1.5 mbps, 2 mbps and 2.5 mbps. If this is evidence of traffic shaping, these are the numbers that ISPs should be using in their promotional materials, rather than the usual “up to” numbers that don’t mention minimums or averages.

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ITExpo East 2011: C-01 “Connecting the Distributed Enterprise via Video”

I will be moderating this panel at IT Expo in Miami on February 3rd at 9:00 am:

Mobility is taking the enterprise space by storm – everyone is toting a smartphone, tablet, laptop, or one of each. It’s all about what device happens to be tIn today’s distributed workforce environment, it’s essential to be able to communicate to employees and customers across the globe both efficiently and effectively. Prior to today, doing so was far more easily said than done because, not only was the technology not in place, but video wasn’t accepted as a form of business communication. Now that video has burst onto the scene by way of Apple’s Facetime, Skype and Gmail video chat, consumers are far more likely to pick video over voice – both in their home and at their workplaces. But, though demand has never been higher, enterprise networks still experience a slow-down when employees attempt to access video streams from the public Internet because the implementation of IP video is not provisioned properly. This session will provide an overview of the main deployment considerations so that IP video can be successfully deployed inside or outside the corporate firewall, without impacting the performance of the network, as well as how networks need to adapt to accommodate widespread desktop video deployments. It will also expose the latest in video compression technology in order to elucidate the relationship between video quality, bandwidth, and storage. With the technology in place, an enterprise can efficiently leverage video communication to lower costs and increase collaboration.

The panelists are:

  • Mike Benson, Regional Vice President, VBrick Systems
  • Anatoli Levine, Sr. Director, Product Management, RADVISION Inc.
  • Matt Collier, Senior Vice President of Corporate Development, LifeSize

VBrick claims to be the leader in video streaming for enterprises. Radvision and LifeSize (a subsidiary of Logitech) are oriented towards video conferencing rather than streaming. It will be interesting to get their respective takes on bandwidth constraints on the WLAN and the access link, and what other impairments are important.

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IT Expo East 2011: NGC-04 “Meeting the Demand for In-building Wireless Networks”

I will be moderating this panel at IT Expo in Miami on February 2nd at 12:00 pm:

Mobility is taking the enterprise space by storm – everyone is toting a smartphone, tablet, laptop, or one of each. It’s all about what device happens to be the most convenient at the time and the theory behind unified communications – anytime, anywhere, any device. The adoption of mobile devices in the home and their relevance in the business space has helped drive a new standard for enterprise networking, which is rapidly becoming a wireless opportunity, offering not only the convenience and flexibility of in-building mobility, but WiFi networks are much easier and cost effective to deploy than Ethernet. Furthermore, the latest wireless standards largely eliminate the traditional performance gap between wired and wireless and, when properly deployed, WiFi networks are at least as secure as wired. This session will discuss the latest trends in enterprise wireless, the secrets to successful deployments, as well as how to make to most of your existing infrastructure while moving forward with your WiFi installation.

The panelists are:

  • Shawn Tsetsilas, Director, WLAN, Cellular Specialties, Inc.
  • Perry Correll, Principal Technologists, Xirrus Inc.
  • Adam Conway, Vice President of Product Management, Aerohive

Cellular Specialties in this context is a system integrator, and one of their partners is Aerohive. Aerohive’s special claim to fame is that they eliminate the WLAN controller, so each access point controls itself in cooperation with its neighbors. The only remaining centralized function is the management. Aerohive claims that this architecture gives them superior scalability, and a lower system cost (since you only pay for the access points, not the controllers).

Xirrus’s product is unusual in a different way, packing a dozen access points into a single sectorized box, to massively increase the bandwidth available in the coverage areas.

So is it true that Wi-Fi has evolved to the point that you no longer need wired ethernet?

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ITExpo East 2011: NGC-02 “The Next Generation of Voice over WLAN”

I will be moderating this panel at IT Expo in Miami on February 2nd at 10:00 am.

Voice over WLAN has been deployed in enterprise applications for years, but has yet to reach mainstream adoption (beyond vertical markets). With technologies like mobile UC, 802.11n, fixed-mobile convergence and VoIP for smartphones raising awareness/demand, there are a number of vendors poised to address market needs by introducing new and innovative devices. This session will look at what industries have already adopted VoWLAN and why – and what benefits they have achieved, as well as the technology trends that make VoWLAN possible.

The panelists are:

  • Russell Knister, Sr. Director, Business Development & Product Marketing, Motorola Solutions
  • Ben Guderian, VP Applications and Ecosystem, Polycom
  • Carlos Torales, Cisco Systems, Inc.

All three of these companies have a venerable history in enterprise Wi-Fi phones; the two original pioneers of enterprise Voice over Wireless LAN were Symbol and Spectralink, which Motorola and Polycom acquired respectively in 2006 and 2007. Cisco announced a Wi-Fi handset (the 7920) to complement their Cisco CallManager in 2003. But the category has obstinately remained a niche for almost a decade.

It has been clear from the outset that cell phones would get Wi-Fi, and it would be redundant to have dedicated Wi-Fi phones. And of course, now that has come to pass. The advent of the iPhone with Wi-Fi in 2007 subdued the objections of the wireless carriers to Wi-Fi and knocked the phone OEMs off the fence. By 2010 you couldn’t really call a phone without Wi-Fi a smartphone, and feature phones aren’t far behind.

So this session will be very interesting, answering questions about why enterprise voice over Wi-Fi has been so confined, and why that will no longer be the case.

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Sharing Wi-Fi Update

Back in February 2009 I wrote about how Atheros’ new chip made it possible for a phone to act as a Wi-Fi hotspot. A couple of months later, David Pogue wrote in the New York Times about a standalone device to do the same thing, the Novatel MiFi 2200. The MiFi is a Wi-Fi access point with a direct connection to the Internet over a cellular data channel. So you can have “a personal Wi-Fi bubble, a private hot spot, that follows you everywhere you go.”

The type of technology that Atheros announced at the beginning of 2009 was put on a standards track at the end of 2009; the “Wi-Fi Direct” standard was launched in October 2010. So far about 25 products have been certified. Two phones have already been announced with Wi-Fi Direct built-in: the Samsung Galaxy S and the LG Optimus Black.

Everybody has a cell phone, so if a cell phone can act as a MiFi, why do you need a MiFi? It’s another by-product of the dysfunctional billing model of the mobile network operators. If they simply bit the bullet and charged à la carte by the gigabyte, they would be happy to encourage you to use as many devices as possible through your phone.

WiFi Direct may force a change in the way that network operators bill. It is such a compelling benefit to consumers, and so trivial to implement for the phone makers, that the mobile network operators may not be able to hold it back.

So if this capability proliferates into all cell phones, we will be able to use Wi-Fi-only tablets and laptops wherever we are. This seems to be bad news for Novatel’s MiFi and for cellular modems in laptops. Which leads to another twist: Qualcomm’s Gobi is by far the leading cellular modem for laptops, and Qualcomm just announced that it is acquiring Atheros.

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Net Neutrality Fallout

Stacey Higginbotham posted an analysis of the FCC Net Neutrality report and order on GigaOM. She concludes:

As a consumer, it’s depressing, …it leaves the mobile field open for the creation of walled gardens and incentivizes the creation of application-specific devices.

Sure enough, just two weeks after the publication of the R&O, Ryan Kim reports on GigaOM that MetroPCS announced on January 3rd plans to charge extra based on what you access, rather than on the quantity or quality of the bandwidth you consume.

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Net Neutrality and consumer benefit

A story in Wired dated December 17th reports on a webinar presented by Allot Communications and Openet.

A slide from the webinar shows how network operators could charge by the type of content being transported rather than by bandwidth:

DPI integrated into Policy Control & Charging

In an earlier post I said that strict net neutrality is appropriate for wired broadband connections, but that for wireless connections the bandwidth is so constrained that the network operators must be able to ration bandwidth in some way. The suggestion of differential charging for bandwidth by content goes way beyond mere rationing. The reason this is egregious is that the bandwidth costs the same to the wireless service provider regardless of what is carried on it. Consumers don’t want to buy content from Internet service providers, they want to buy connectivity – access to the Internet.

In cases where a carrier can legitimately claim to add value it would make sense to let them charge more. For example, real-time communications demands traffic prioritization and tighter timing constraints than other content. Consumers may be willing to pay a little bit more for the better sounding calls resulting from this.

But this should be the consumer’s choice. Allowing mandatory charging for what is currently available free on the Internet would mean the death of the mobile Internet, and its replacement with something like interactive IP-based cable TV service. The Internet is currently a free market where the best and best marketed products win. Per-content charging would close this down, replacing it with an environment where product managers at carriers would decide who is going to be the next Facebook or Google, kind of like AOL or Compuserve before the Internet. The lesson of the Internet is that a dumb network connecting content creators with content consumers leads to massive innovation and value creation. The lesson of the PSTN is that an “intelligent network,” where network operators control the content, leads to decades of stagnation.

In a really free market, producers get paid for adding value. Since charging per content by carriers doesn’t add value, but merely diverts revenue from content producers to the carriers, it would be impossible in a free market. If a wireless carrier successfully attempted this, it would indicate that wireless Internet access is not a free market, but something more like a monopoly or cartel which should be regulated for the public good.

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Video calling from your cell phone

Although phone numbers are an antiquated kind of thing, we are sufficiently beaten down by the machines that we think of it as natural to identify a person by a 10 digit number. Maybe the demise of the numeric phone keypad as big touch-screens take over will change matters on this front. But meanwhile, phone numbers are holding us back in important ways. Because phone numbers are bound to the PSTN, which doesn’t carry video calls, it is harder to make video calls than voice, because we don’t have people’s video addresses so handy.

This year, three new products attempted to address this issue in remarkably similar ways – clearly an idea whose time has come. The products are Apple’s FaceTime, Cisco’s IME and a startup product called Tango.

In all three of these products, you make a call to a regular phone number, which triggers a video session over the Internet. You only need the phone number – the Internet addressing is handled automatically. The two problems the automatic addressing has to handle are finding a candidate address, then verifying that it is the right one. Here’s how each of those three new products does the job:

1. FaceTime. When you first start FaceTime, it sends an SMS (text message) to an Apple server. The SMS contains sufficient information for the Apple server to reliably associate your phone number with the XMPP (push services) client running on your iPhone. With this authentication performed, anybody else who has your phone number in their address book on their iPhone or Mac can place a videophone call to you via FaceTime.

2. Cisco IME (Inter-Company Media Engine). The protocol used by IME to securely associate your phone number with your IP address is ViPR (Verification Involving PSTN Reachability), an open protocol specified in several IETF drafts co-authored by Jonathan Rosenberg who is now at Skype. ViPR can be embodied in a network box like IME, or in an endpoint like a phone of PC.
Here’s how it works: you make a phone call in the usual way. After you hang up, ViPR looks up the phone number you called to see if it is also ViPR-enabled. If it is, ViPR performs a secure mutual verification, by using proof-of-knowledge of the previous PSTN call as a shared secret. The next time you dial that phone number, ViPR makes the call through the Internet rather than through the phone network, so you can do wideband audio and video with no per-minute charge. A major difference between ViPR and FaceTime or Tango is that ViPR does not have a central registration server. The directory that ViPR looks up phone numbers in is stored in a distributed hash table (DHT). This is basically a distributed database with the contents stored across the network. Each ViPR participant contributes a little bit of storage to the network. The DHT itself defines an algorithm – called Chord – which describes how each node connects to other nodes, and how to look up information.

3. Tango, like FaceTime, has its own registration servers. The authentication on these works slightly differently. When you register with Tango, it looks in the address book on your iPhone for other registered Tango users, and displays them in your Tango address book. So if you already know somebody’s phone number, and that person is a registered Tango user, Tango lets you call them in video over the Internet.