notes from the 4G WiMAX Developer's Symposium at Stanford (part 1)

The 4G WiMAX Developer's Symposium at Stanford on June 15th provided a full day of presentations on Clearwire/Sprint's growing 4G network, including demonstrations from several startups on how they intend to exploit the increased mobile broadband capacity, followed by a review of ongoing trends and visions of future developments. For the full agenda, see my earlier post.

The opening keynotes were:

10:30 – 11:00am	Keynote: 4G Growth & Momentum	Terese Elder: Clearwire President of Wholesale
11:00 – 11:30am	Keynote: Exciting Times in BB wireless	Bob Azzi: Sprint Senior Vice President, Network

In her presentation, Clearwire's Terese Elder covered the current status of the WiMAX service (covering 34 markets today), while reiterating the target for 120M pops by the end of 2010. 

She also cited a number of statistics from Morgan Stanley:

• Projected 10B mobile devices 2010-2020.
• More than just phones, there will be 10X more mobile connected devices than fixed.
• Mobile users will exceed desktop in 5 yrs.
• Smartphones will out ship notebooks + netbooks 2010, and global PC market in 2012.
• Market opportunity: 36% growth in mobile broadband subscribers, 24% growth in revenue ($3B-$10B) (2014) 

Her comment that "it will be interesting to see what happens with VOIP, Skype" is noteworthy. While voice revenues are declining, the future LTE operators continue to debate how to integrate voice and data in their 4G plans.

Will voice continue to be treated as a separate service (at an additional fee), or will the voice bits be bundled along with the rest of 4G data in an all-IP network? Clearwire  supported the Skype app previously on the Samsung Mondi, the 1st WiMAX MID which was introduced last year.  According to Ms. Elder, "Skype has more registered users than any carrier in the world".

Looking beyond VOIP and video, this was her list of "killer" 4G apps:

• cloud computing goes mobile.
• users spending more time on social networking than email
• business content for the enterprise

In his presentation Bob Azzi, Senior VP Networks at Sprint, picked up on the plans for WiMAX rollout, stating that "San Francisco and San Jose are on the list for 2010". Clearwire's Silicon Valley WiMAX Innovation Network currently includes base stations on the Stanford campus in Palo Alto, at Intel in Santa Clara, and at Google in Mountain View.

While pointing to the recent introduction of the HTC EVO, Mr. Azzi gave his description of the "4G experience" and how subscribers are making use of WiMAX:

• 2-way video conferencing (QIK)
• unified communications
• WiFi enablement (i.e. the hotspot feature of the EVO, and the Sprint Overdrive)
• network redundancy for landlines
• media content adds hidef, full length video
• live video surveillance
• simultaneous app viewing

Sprint's Azzi also reviewed the advantages offered by Clearwire's spectrum position (120-150 MHz at 2.5GHz), comparing it to the 12-46 MHz of 700 MHz and AWS spectrum that competitors such as Verizon Wireless will deploy for LTE. This is a topic I covered thoroughly last year in my report on "The Emerging 4G Wireless Landscape in the U.S.".

In order to make his point regarding the spectrum-capacity advantage, Mr. Azzi showed a chart something like the one I have reproduced above.  This graph is based on a claimed capacity for Sprint 4G of 420Mbps per tower, compared to an LTE competitor's (read Verizon Wireless LTE here) of 100 Mbps per tower.

This chart is somewhat deceptive, since Clearwire currently deploys their WiMAX spectrum in three 10MHz sectors per tower. With less spectrum for LTE, Verizon is expected to deploy one sector per tower (paired: 10 MHz uplink, and 10 MHz downlink). When asked, Mr. Azzi said this difference is based on deploying all 150 MHz of capacity at each tower (which is not likely).

If we break down the numbers then,we should divide the Clearwire Mbps/user by a factor of 5. The result is that the projected speeds that users can expect from Clearwire and Verizon are just about identical. This is much more in line with actual reported results.

One more caveat though: this only applies to the downlink. Clearwire is currently capping the upload date rate to 1Mbps. As I have reported in the past, this is an issue with the promotion of video conferencing as a "killer app" for WiMAX. In upload, Verizon's LTE has a potential advantage due to the FDD vs. TDD nature of the spectrum resource. In response to my question after his presentation, Mr. Azzi said they are continuing to watch this, but any adjustment will require trading off download for upload speed. 

In video conferencing the lower resolution 1.3Mpixel front-side camera of the HTC EVO does produce much less of a load on the network than the 8 Mpixel back-side camera, but upload streaming apps could definitely suffer. This is also exactly why the (over-hyped ) iPhone 4 "FaceTime" app will be WiFi only.

Finally, in regards to the spectrum comparison, Mr. Azzi also pointed out that they have 800Mhz and 1900 Mhz spectrum that can be re-deployed in the future. For enhancing coverage, he also made the statement that Sprint will "evolve femto cells from 3G to 4G".

-Mike

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