A very interesting play, perhaps most amusing for wireless engineers, centered around the story of frequency hopping.
http://www.sciam.com/article.cfm?id=hedy-lamarr-not-just-a-pr
I like how they use the music analogy. Perhaps the first hopping algorithm was something like “Scott Joplin’s Entertainer” since Bach would be easily recognized by the Germans.
Today I came across a nice result on the distribution of eigen values of matrix 
, where the entries of 
are i.i.d. Gaussian distributed. The result says that the 
eigen value 
(in the decreasing order) of has the following distribution, 
for small 
.
Its quite useful for analysing many MIMO techniques, such as MRC, MRT.
The reference is a recent IT Paper: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4544985&isnumber=4544949
It turns out that the mysterious “green sheet” is just the WNCG graduation checklist. You can find it at this link.
A student from China recently asked me about how I got interested in relay selection and started obtaining (publishable) results. Since I have some free time on my hands now, I figured I’d share some thoughts on this topic.
I actually don’t think that the way I got interested in relay selection was the ideal strategy in terms of “finding a good research topic.” Instead, I’ll discuss what I think is a better way of “finding a good research topic.” Note that the following is especially relevant for graduate students researching wireless communications (for the obvious reasons).
It’s fairly common for a new graduate student to be overwhelmed by the plethora of potential research topics. When I was starting work on my masters degree, I wanted to do research involving some aspect of wireless networks, since I felt (wrongly, as it turned out) that all of the good point-to-point problems had already been solved. During the summer of 2004, I worked on beamforming for MIMO ad hoc networks, but that ended up being a major dead end. On a related note, I recently perused my research notebook and found that during January 2006, I was interested in cooperative diversity for OFDM networks (my, how things have changed).
This brings up the key question: how should a new graduate student sort through the morass of potential research topics and come up with a good one? I’ll discuss two potential answers.
One approach is to have your advisor answer this question for you, assuming that you have an advisor. In general, you can assume that your advisor has a strong grasp of the current state of research in wireless communications. This knowledge can help him/her determine a topic for you that is 1) interesting, so you won’t be bored stiff for approximately 5 years and 2) worthy of a Ph.D. dissertation, so you will have made a fundamental contribution of some sort by the time you graduate.
The second approach, which I highly recommend, is to take the initiative. To start off, you should do a significant amount of reading. Survey articles in journals such as the IEEE Communications Magazine and the IEEE Signal Processing Magazine can be valuable starting points for the interested yet relatively inexperienced grad student.
A particularly well-written survey article can provide the reader with a good grasp of “what’s been done” on a topic such as “OFDMA power allocation for relay-based networks” and suggest various open problems that are both interesting and important. When reading through these survey articles, one should also scan the list of references to learn about the key papers (and researchers, so you can bookmark their home pages) in a particular area.
It’s then important to read through these key papers to grasp the nuances of the topic that you’re learning about and ask yourself tough questions along the way. For example, do you understand the (technical) paper that you’re reading? Can you justify all of the authors’ assumptions? Can you re-derive every expression (especially the proofs of key theorems) in the paper? I should note that sometimes papers contain typos/gross errors, so you shouldn’t automatically trust everything you read.
If you want to answer these questions in the affirmative, this is a great opportunity for building your technical background. For example, let’s say that the authors are studying a MIMO wireless system and assume that a two-ring scattering model is being employed. If you don’t know what a two-ring scattering model is, you should obtain a copy of a MIMO textbook such as this one by Paulraj et al. and learn more about channel modeling.
Also, let’s say that you’re reading through this famous paper by Gupta and Kumar, and you’re having trouble deriving some (or all, as this paper is actually quite tricky to understand) of the key results. In this case, you might want to strengthen your graph theory background by taking an appropriate class, such as this one at UT-Austin. You might also want to improve your knowledge of random geometry, and you can check your university library for a helpful book such as this one by Bollobas for more coverage of this advanced topic.
As you read through the key technical papers in the area that you’re learning about, you should think of additional open problems and ask yourself more tough questions. For example, you can ponder something like, “the authors’ assumption of a zero-error feedback channel seems a bit restrictive. From my other reading it’s clear that introducing a channel estimation error at the transmitter would better model a practical system. Maybe I can’t obtain an exact expression for the sum capacity given channel estimation errors, since that seems quite complicated, but can I obtain relatively tight bounds?”
Regardless of the approach that you take in terms of finding a good research topic, it’s crucial that you interact with your advisor during this process. Your advisor, who has worked in either the general area that you’re considering or a related area, can help you determine if the open problem you’re considering is either trivial, worthy of multiple dissertations, or actually reasonable for a dissertation. Note that by adopting the second approach I discussed above, your ability to have meaningful dialogue with your advisor during this process is enhanced. In particular, you can evaluate your advisor’s suggestions and converge on a reasonable topic more quickly; this is especially important if your advisor has not worked in the general area that you’re considering.
That’s all I had to say on this subject, at least for now. I welcome comments, especially from my group-mates on this issue of “finding a good research topic.”
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.
Some of you may be curious to know about the “gold sheet.” Now I shall shed some light on this subject; I’ll also be posting this on the WSIL Wiki.
The gold sheet has an official letterhead (from the Office of the Vice Provost and Dean of Graduate Studies). Now for the rest of the form…
REPORT OF DISSERTATION DEFENSE
The Doctoral Dissertation Committee for (your official name)
(your UT EID)
Has conducted a final examination on: (your defense date)
On the dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. The student has passed the final oral; completed a dissertation which is an independent investigation and which constitutes an original contribution to knowledge; and submitted for publication in Dissertation Abstracts International an abstract, which meets the approval of the Committee.
Then there are six lines for the signatures of your committee members, with the first line labeled as “Signature of Supervisor.”
The Graduate Studies Committee has determined this student has completed all assigned work and passed all examinations required by the graduate program, and recommends that the degree of Doctor of Philosophy be granted.
Finally there are two lines for the signature of the ECE GSC Chair (currently Dr. Jack Lee) and the date of the Chair’s signature. You should submit the form to Melanie on the first floor, and after Dr. Lee signs it, someone from the ECE grad office will take it to the Doctoral Degree Evaluator in the Main Building for you.
Unfortunately, it appears that the mysterious “green sheet” actually does not exist. If I happen upon it for some reason, I will make another post on that.
As I have just submitted the mysterious “pink sheet,” I can now shed some light on it.
The pink sheet is the “request for final oral examination.” There’s a note at the top stating that this “form must be on pink paper; it will not be accepted otherwise,” which I found to be both amusing and bewildering. I asked Melanie Gulick about this, and she said that it was a holdover from the days when all important forms needed to be color-coded.
The form has places for you to list your name, EID, address, and your phone number. You also state the date/time/place of your defense. In addition, you sign the form to allow UT to publicize your defense.
Each member of your committee needs to sign the form to indicate that they’ve received a copy of your dissertation and agree to attend your defense. If any of your committee members plans to attend the defense but can’t sign the form, your advisor (or Dean Neikirk) can sign the form in their place. Then, Dean Neikirk needs to sign the form.
If any of your committee members can’t attend the defense, they can indicate that by signing the back of the form (again, your advisor or Dean Neikirk can act as a proxy in this case).
When you submit the pink sheet to the Graduate School in the Main Building, you also bring along a hard copy of your abstract, vita, title page and “committee certification of approved version” (which will require more signatures). The doctoral degree evaluator does a cursory check of those pages to see if there are any obvious formatting errors.
Assuming all goes well, I will learn about the “gold sheet” and the “green sheet” (if they actually exist).
Light up Turn on Engage
Laptop and Terminal Euphoria
Linking The Earth
Linking Telephony Everywhere
Luscious Telephony Experience
Limitless Technology for Everyone
Limited Time Enigma
Laugh Track Escapade
Lightning-fast Transfer of Everything
Let’s Turnaround East
Late Troublesome Expensive
Look, Talk, and Enjoy
Live Telecommunication Environment
Leading Telecommunication Excellence
Loads of Traffic for Everyone
Live connection To Everyone
Live communication To Everyone
Lifeline To Everyone
Let’s Take it Easy
Life Time Eternal
Love Thy Enemy
Link Technology Enhancement
Legacy Terminal Equipment
- from LTE / LTE-A TSG RAN mailing list
Some people also say “Long Term Employment” or “Life Time Employment.” :)
But my pick is “Love Thy Enemy.” How about you?
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:
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.
For U.S. PhD-degree holders, don’t use the title “Dr.” in your business cards when you visit Germany. If not, you may face a year behind bars.
Note: this news was not posted on April 1st.
