Author Archive

Inventor of frequency hopping

Miscellaneous No Comments »

A very interesting play, perhaps most amusing for wireless engineers, centered around the story of frequency hopping.

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.

V2V Communications in Japan

Miscellaneous No Comments »

Recently, there has been increased discussion on Vehicle-to-Vehicle (V2V) communications. I find this area to be interesting and challenging to the wireless engineer because it opens a completely new field for radio environment, demands, application, etc. (Yes, systems like trunked radio has been around for few decades but I assume we’re talking more than a simple FM system.) Since vehicles are central to our lives, especially in the US, this is probably the best place for applications to emerge. Being a gearhead certainly adds to my interest.

I cannot say that I fully follow the V2V activities, but the following news caught my attention which seems to indicate that there is a strong movement towards V2V communication and ITS in Japan.

On Feb. 4, 2008, Denso announced the beginning of Vehicle-to-Vehicle communication tests on public roads in Japan (see press release here). It uses 669 - 679 MHz UHF and 5.8GHz band DSRC. The V2V communication is apparently part of the Japanese Ministry of Internal Affairs and Communications’ initiative “Ubiquitous ITS”, which includes digital video broadcast (or VICS, vehicle information and communication system), 60-76GHz mm-wave sensor application, cellular service, short range applications (expressway tollgates, DSRC, wireless service transaction, etc).

The reason for using 669-679MHz above is only to avoid interference with the TV broadcast in the 700MHz band, of which 715-725MHz is expected to open for ITS use in 2011 when the analog TV broadcast goes off air in the 700MHz band.

Some interesting areas of ITS are identified here at the ITS Japan website.Traditional wireless systems (cellular, WiFi, etc) has always had a  clear demand: cellular service to provide bidirectional voice services, and WiFi to provide fast download and so-so upload. For ITS, at least to me, it is not clear what kind of data traffics are needed, that is to say, what type of wireless technologies should be used to support the service. Look at it another way, this area is wide open with possible applications, technologies to support it, and perhaps new business models.

So I thought it would be interesting to throw out a question: What can we do in ITS?

Does MIMO enable certain applications? Or will new applications drive towards new technology?

Some links for further reading:

Food for the Eyes

Miscellaneous 1 Comment »

Slightly off topic… I came across this news today. A cool application of MEMS sure to fire up some imagination or vision!?

The news article here

We’ve all seen something similar in some SciFi movie. Imagine the things you can do. Connect wirelessly to display information about your location within your vision, a cheat sheet display for your next big talk, etc…

Unfortunately, it appears that there is no clean way to feed power and information signal to it other having a wire dangling from your eyes (ouch!). Maybe a RFID-like passive display could be of immediate use.

To give a MIMO flavor, maybe some form of MIMO visual communication is possible…

4G spectrum agreed at ITU-R

WSIL News & Views 5 Comments »

This is perhaps the first big move towards the 4G mobile wireless system that has been in the talks for the last 5 years or so. Today, ITU-R at the World Radiocommunication Conference (WRC ‘07) has agreed on the spectrum for 4G.

  • 450−470 MHz band
  • 698−862 MHz band in Region 2 and nine countries of Region 3
  • 790−862 MHz band in Regions 1 and 3
  • 2.3−2.4 GHz band
  • 3.4−3.6 GHz band (no global allocation, but accepted by many countries)

Now the question is what the radio specification will be for 4G (=IMT-Advanced).

Future Wireless with Nano

WSIL News & Views 1 Comment »

I have been watching the developments in nanotechnology as a potential enabler for the new generation of wireless systems. I was initally captivated by the idea of creating a vaccum tube on a wafer using carbon nano tubes. While traditional vaccum tubes are inefficient, they have very high gains which are difficult to realize in solid state electronics. I think analog signal processing is bound to come back…

In any case, I think this paper is a significant stepping stone towards this direction. The paper is here. They even have a demo video (and a nice taste for Irish music).

Slide template using LaTeX

Reference 1 Comment »

Hi all, my first post here.

In my attempt to simplify the process of creating slides, especially with equations, I have created a WNCG template slides using HA-prosper. This package will allow you to create nice looking slides using our best friend, LaTeX. I am posting this here in case anyone would like to reuse this template.

You can download the working package here.
And the HA-Prosper manual here (for misc tweaking).

The package contains:

  • Core files
    • WNCGTemplate.tex - Main TeX file
    • HAPWNCG.sty - Style file
    • UTECElogo.eps - UT ECE logo
    • WNCGLogo.eps - WNCG logo
  • Supporting files for this example
    • bf_mimo.eps
    • Research.bib
    • IEEEtran.bst
  • WNCGTemplate.pdf - Precompiled PDF slide

The compile process follows the usual procedure.

  1. LaTeX it once to catch the references
  2. Run Bibtex
  3. Latex twice to get the references
  4. dvips
  5. ps2pdf

I have not found a way to compile in one step using pdflatex. Please let me know if you find a way :-)

One catch about using HA-prosper is that it includes the logos for each page, thus creating a pretty large PS/PDF file. This is documented in HA-prosper manual and there seems to be no work around at this point.

I hope you find it useful. Any comment/suggestions for improvements or sarcasm are welcome!