The WindoWSIL

San Francisco was the site of the 2008 WiNTECH Workshop, which held a contest between teams presenting demonstrations of their research prototypes. The theme of the contest was “The Next Big Thing in Wireless”, and consisted of teams building real wireless systems and giving a live demonstration of their capabilities.

The winning team consisted of Robert C. Daniels, Ketan Mandke, Steven W. Peters, Prof. Scott M. Nettles, and Prof. Robert W. Heath, Jr., and their winning presentation was called “Machine Learning for Physical Layer Link Adaptation in Multiple-Antenna Wireless Networks”. Daniels and Peters are graduate students in the WSIL, which is directed by Prof. Heath. The demo consisted of using simple machine learning techniques to do adaptation in wireless devices using a custom-built IEEE 802.11n physical layer (PHY). Because this PHY uses coded MIMO-OFDM, adaptation is a difficult prospect. The team successfully demonstrated that the devices were learning the channel with no pre-existing knowledge, and could easily adapt to changing conditions. They used the Hydra prototype, which is in continuous development, as the foundation for the demo.

The winning students received a $2500 cash prize kindly donated by the sponsors, ViaSat, Nokia Siemens Networks, The Center for Multimedia Communication, and BBN Technologies.

The work was sponsored in part by NSF and DARPA ITMANET.

Although there is still a week of finals, the semester is basically finished. This has been my most eventful semester, personally, but how did the WSIL fare? Let’s take a look.

First and foremost, our dear Kaibin Huang just successfully defended his dissertation and is on his way to a post-doc at Hong Kong University of Science and Technology. Not only that, but he was awarded the WNCG Student Leadership award. A WSIL member has won this award two of the past three years.

Along the same lines, Takao Inoue is now a Ph.D. Candidate. He joins Chan-Byoung Chae and Caleb Lo as the next in line to graduate.

We also welcomed the well-known Dr. Marios Kountouris as a post-doctoral researcher.

In addition, we had eight journal papers published:

• R. C. Daniels R. W. Heath, Jr., “60 GHz Wireless Communications: Emerging Requirements and Design Recommendations,'’ IEEE Vehicular Technology Magazine, vol. 2, no. 3, pp. 41-50, Sept. 2007. [IEEE Xplore]
• J. G. Andrews, W. Choi, and R. W. Heath, Jr., “Overcoming interference in spatial multiplexing MIMO cellular networks,'’ IEEE Wireless Communications, vol. 14, no. 6, pp. 95-104, Dec. 2007. [IEEE Xplore]
• W. Choi, A. Forenza, J. G. Andrews, and R. W. Heath, Jr., “Opportunistic space division multiple access with beam selection,'’ IEEE Trans. on Communications, vol. 55, no. 12, pp. 2371-2380, Dec. 2007. [IEEE Xplore]
• K. Huang, R. W. Heath, Jr., and J. G. Andrews, “Uplink SDMA with Limited Feedback: Throughput Scaling,'’ EURASIP Journal on Advances in Signal Processing, special issue on MIMO Transmission with Limited Feedback, vol. 2008, Article ID 479357, 17 pages, doi:10.1155/2008/479357, 2008. [EURASIP Website]
• B. Mondal and R. W. Heath, Jr., “A Diversity Guarantee and SNR Performance for Quantized Precoded MIMO Systems,'’ EURASIP Journal on Advances in Signal Processing, special issue on MIMO Transmission with Limited Feedback, vol. 2008, Article ID 594928, 15 pages, doi:10.1155/2008/594928, 2008. [EURASIP Website]
• Kyung Seung Ahn, R. W. Heath, Jr., and H. K. Baik, “Shannon Capacity and Symbol Error Rate of Space-Time Block Codes in MIMO Rayleigh Channels with Channel Estimation Error,'’ IEEE Trans. on Wireless Communications, vol. 7, no. 1, pp. 324-333, Jan. 2008. [IEEE Xplore]
• C. B. Chae, T. Tang, R. W. Heath, Jr., and S. Cho, “MIMO Relaying with Linear Processing for Multiuser Transmission in Fixed Relay Networks,'’ IEEE Trans. on Signal Processing, vol. 56, no. 2, pp. 727-738, Feb. 2008. [IEEE Xplore]
• D. Piazza, N. J. Kirsch, A. Forenza, R. W. Heath, Jr., and K. R. Dandekar, “Design and Evaluation of a Reconfigurable Antenna Array for MIMO Systems,'’ IEEE Trans. on Antennas and Propagation, vol. 56, no. 3, pp. 869-881, Mar. 2008. [IEEE Xplore]

In addition, our fearless leader Prof. Heath, along with Prof. Andrews, won the WNCG Spring 2008 Bocce Ball tournament.

And finally, a long semester of ups and downs concludes with a nice week in the U.S. Virgin Islands for the IEEE Communication Theory Workshop, with Prof. Heath as General Chair.

Please add more here if I forgot something.

Draft 3 of IEEE 802.16j has been finished and letter ballot voting has begun. Voting closes March 15th. While Draft 2 officially passed letter ballot, resolutions to comments made with “Disapprove” votes need to be made before moving on in the process. The official announcement is available online, and you can monitor voting progress as well. The document is not available for free to the public, but in due time it will be available for purchase.

Some of you may be familiar with the Erdos number in mathematics. This number is sort of a “degrees of separation”, in publication terms, from one Paul Erdos. I did a little surfing and found out that Prof. Heath’s Erdos number is about to become 6, if a recently submitted article is accepted.

Claude Shannon has an Erdos number of 3. Also, Bob Gallager published a couple papers with Shannon, one of them being:

Claude E. Shannon, Robert G. Gallager, Elwyn R. Berlekamp: Lower Bounds to Error Probability for Coding on Discrete Memoryless Channels. I Information and Control 10(1): 65-103 (1967)

One of Gallager’s students was Randall Berry:

Randall A. Berry, Robert G. Gallager: Communication over fading channels with delay constraints. IEEE Transactions on Information Theory 48(5): 1135-1149 (2002)

Finally, a recently submitted article to IEEE Communications magazine is co-authored by Prof. Heath and Prof. Berry, collaboraters on the DARPA IT-MANET project:

J. G. Andrews, N. Jindal, M. Haenggi, R. Berry, S. Jafar, D. Guo, S. Shakkottai, R. W. Heath, Jr., M. Neely, S. Weber, A. Yener, P. Stone, “Rethinking Information Theory for Mobile Ad Hoc Networks,'’ submitted to IEEE Communications Magazine Dec. 2007.

If this is accepted, it will give anyone connected to Prof. Heath an Erdos number of at most 7. It’s amazing how connected we all are. Albert Einstein has an Erdos number of 2, so (at most) 9 papers separate us from Albert Einstein. Isn’t that crazy?

If you’re not a member of WSIL, what is your Erdos number?

The IEEE is without a doubt the society whose publications we submit to (and read from) the most. They have recently released an 18-page style manual (pdf) that all transactions adhere to. Some of the more useful sections include proper referencing of different things (references make up about 14 pages of the document), proper abbreviations, and where in the paper to acknowledge funding.

IEEE P802.16j/D2 passed letter ballot today. After comments on the draft made by negative voters are resolved, the draft will move to Sponsor Ballot and then on the the Standards Board Review Committee (RevCom). I expect it will be approved by the Standards Board by October.

There’s a really nice article* in this month’s IEEE Spectrum Magazine about Sprint’s Xohm, which will provide the first WiMAX service in the United States. I’m usually not too excited about this kind of stuff, but I will definitely look into it when it is offered here in Austin. This year they plan on deploying in Chicago, Baltimore, and Washington, D.C., followed by New York City.

Perks:

• 2-4 Mbps, which is 4-8 times faster than 3G.
• Equipment available will include laptop adapters, mobile phones, and home modems, meaning one service can give you broadband access to your home, give you a WiFi-like hotspot anywhere in the city, and be your mobile phone.
• Prices are expected to be competitive with DSL.
• No contracts.

Now we just have to hope WiMAX equipment isn’t too expensive.

The second draft of IEEE 802.16j, the Multihop Relay amendment to IEEE 802.16e/Mobile WiMAX, is currently being voted on by IEEE 802.16 members. The first draft only garnered a 67% approval while needing 75%. Over 1050 comments have been resolved since Draft 1, and so far the turnout has looked positive—6 people have changed their vote from Disapprove to Approve so far; 2 changed from Abstain to Approve; 1 that did not vote before now Approves.

Votes from the first ballot carry over if the person does not vote again, which means if no one else votes between now and January 14th–when the ballot closes–Draft 2 will have a 69.85% approval, meaning it will fail again. However, by the number of changes in votes so far, I’m betting this draft will be approved by a narrow margin.

I know this is Bob’s thing, but he’s busy doing real engineering work at the moment.

This semester has gone by extremely quickly. Unbelievably, I’ve been in WSIL for six months already. Amazing.

I’ll first present the latest news. Sumohana Channappayya successfully defended his dissertation and will be heading to San Diego to join the real world as a newly anointed Ph.D. Congratulations, Sumo!

Along similar lines, Caleb Lo and Chan-Byoung Chae both successfully passed quals yesterday. These two, along with Kaibin Huang, are next in line to graduate.

Further, we have published, submitted, or have had accepted numerous papers on topics ranging from prototyping to information theory. In particular, we published the following seven journal papers this semester:

• R. Chen, J. G. Andrews, R. W. Heath, Jr., and A. Ghosh, “Uplink Power Control in Multi-Cell Spatial Multiplexing Wireless Systems,” IEEE Trans. on Wireless, vol. 6, no. 7, pp. 2700-2711, July 2007. [IEEE Xplore]
• A. Forenza, D. J. Love, and R. W. Heath, Jr., “Simplified Spatial Correlation Models for Clustered MIMO Channels with Different Array Configurations,'’ IEEE Trans. on Veh. Tech., vol. 56, no. 4, part 2, pp. 1924-1934, July 2007. [IEEE Xplore]
• K. Huang, R. W. Heath, Jr., and J. G. Andrews, “Space Division Multiple Access with a Sum Feedback Rate Constraint”, IEEE Trans. on Signal Processing, pp 3879-3891, Jul. 2007. [IEEE Xplore]
• B. Mondal and R. W. Heath, Jr., “Quantization on the Grassmann Manifold,'’ IEEE Trans. on Signal Processing, vol. 55, no. 8, pp. 4208-4216, Aug. 2007. [IEEE Xplore]
• V. Raghavan, R. W. Heath, Jr., and A. Sayeed, “Systematic Codebook Designs for Quantized Beamforming in Correlated MIMO Channels,'’ IEEE Journal on Sel. Areas in Comm., Special Issue on Optimization of MIMO Transceivers for Realistic Communication Networks: Challenges and Opportunities, vol. 25, no. 7. pp. 1298-1310, Sept. 2007. [IEEE Xplore]
• M. R. McKay, I. B. Collings, A. Forenza, and R. W. Heath, Jr., “Multiplexing/Beamforming Switching for Coded MIMO in Spatially Correlated Channels Based on Closed-Form BER Approximations,'’ IEEE Transactions on Vehicular Technology, vol. 56, no. 5, part 1. pp. 2555-2567, Sept. 2007. [IEEE Xplore]
• D. Gesbert, M. Kountouris, R. W. Heath, Jr., C. B. Chae, and T. Salzer, ‘Shifting the MIMO Paradigm: From Single User to Multiuser Communications,’ IEEE Signal Processing Magazine, Vol. 24, No. 5, pp. 36-46, Oct., 2007 [IEEE Xplore]
  

Also, first year grad student Alvin Leung taught us all a ping pong lesson in the first annual WSIL ping pong tournament. His skills will surely diminish as grad school takes over his life.

There really was so much more to this semester. In many ways, Fall 07 will be remembered as a semester where a lot of work was put into projects that other semesters will be able to claim to have finished, as this semester did with the above journal papers. We submitted far more journal papers than we published. We welcomed 6 new members and said goodbye to only 1. And we put in hundreds of hours into projects whose payoffs are still months away. In that way, you might say it was a blue-collared semester.

If anyone else has something to add (feel free to toot your own horn), please comment.

Back in the day I used to frequent some grad school discussion boards on the internet. Yes, I’m a loser (I can feel Bob laughing at me already). It really struck me how different the grad school experience is in the rest of the world. For instance, at Ali’s M.S. university in Canada, he had to defend his M.S. thesis. In Australia, they don’t even have to defend their Ph.D. thesis. Even more astounding, in Europe and Australia (and probably several other places), a PhD generally takes three years after a bachelors. And they have no coursework.

On the other hand, in North America, we are required to earn Master’s degrees before our Ph.D. (or Sc.D.), and must take quite a few courses to do so, the exact amount of which varies from school to school. I believe I heard the average time from bachelors to Ph.D. in the U.S. is around 5.5 years.

How can it take more than two more years for us to get our Ph.D.’s relative to other areas of the world? Do we learn more? Are we less prepared? Are our programs less intense? Certainly at least one of these has to be true to some extent.

When Dan Ryan (from CSIRO in Australia) came to visit the WSIL this summer, he said classes are pointless for grad school; we should be able to learn everything we need to know out of a book. What is our response to this?

I’m afraid I only have questions on this topic.