Look at your TV today. It receives analog free-to-air TV signals using some built-in receiver circuitry. If your TV is capable of receiving digital channels, great – but did you know that it actually uses a separate set of receiver circuitry to make it happen? That’s why for those with an older TV set, they need to get a set-top box to get the digital channels. Wouldn’t it be great if we can use the one set of hardware to receive every channel out there, be it analog TV, digital terrestrial TV, satellite TV and even the TV standards yet to be developed? Well that’s what software radio here for.
Throughout this year, I was busily working on my undergraduate thesis project, with the goal of developing a software based transmission system for satellite TV. In particular, I wanted to implement the European standard DVB-S using a general purpose computer and the free software radio framework called GNU Radio and a generic radio device called the USRP from Ettus Research.
How did I go? It worked! I was able to correctly decode the captured signal from the satellite and recover the MPEG-2 transport stream that can be played using MPlayer, but unfortunately that’s not the end of the story. Ideally we’d like to receive the satellite signal and decode it in real-time, but our processing speed hasn’t quite got there yet. The performance can be summarised in the figure below:
In this chart, we’ve taken the throughput of each component signal processing block in the receive chain and normalised it to a value of 1 meaning that it’s just able to run in real-time assuming that each block can be run in parallel. A value of lower than 1 means that it’s slower than real-time while values greater than 1 mean it’s more than fast enough for real-time processing. Looking at the proportion of CPU time spent in decoding, there are only three blocks taking up most of the time: the Viterbi decoder, the M-PSK receiver for symbol timing recovery and the frequency correcting frequency locked loop:
So what we need to do now is improve the efficiency and throughput of each of those blocks, then we should be well on our way to real-time, satellite TV decoding on completely generic and reconfigurable software radio on the computer!
More details can be found in my treatise, which can be found under my blog’s Sydney Uni page.
This semester, I’m doing a entrepreneurial course as a finale to my 5 years undergrad at uni. The course is run by Matt Barrie (CEO, Freelancer.com) and Bill Bartee (Managing Partner, Southern Cross Ventures).
A feature of this course is that it is heavily industry-focused, and every week, we have successful real-world entrepreneurs (not just a lecturer) as guest speakers to share their experience and expertise.
Ask TVC is a site our group have launched to share this exclusive opportunity with the world. If you are running a business, or thinking about getting into the game, then fire your questions away. We’ll gather the top rated questions for each speaker and we’ll post the answers after the lecture.
The answers to Tjoos.com (Kim Chen and Bart Jallema) questions are now posted, and we still have Viocorp (Ian Gardiner), Omnisio (now YouTube; Ryan Junee), Atlassian (Mike Cannon-Brookes), and many more to come!
So check us out at asktvc.nfshost.com and let us know what you think.
After a bit of distraction, my study notes for ELEC5616 Computer and Network Security is finally finished and have been posted. As usual, it’s up my my Sydney Uni page.
Exams for semester 1 this year are finally over. The first set of notes to go up is for ELEC5509 Mobile Networks taught by Abbas Jamalipour. As usual, you’ll be able to find it at my Sydney Uni section of the blog.
I would have to say that this course is one of the least enjoyable and least rewarding courses I’ve done over the years, and would strongly advise those doing Telecommunications Engineering at USYD to not take this course.
Read on for a brief review of the course.
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We have had a great time this week, and thank you to everyone whom attended. This Macquarie sign is from the top of their new “activity-based†building at Shelley St. For those who missed out, it’s not like any other office buildings you’ve ever seen before. Keep an eye out for when SUITS runs another one of these extraordinary visits again perhaps next year!
I want to take this opportunity to thank Will from Google, Robyn from Atlassian and Larissa from our sponsor Optiver whom have worked with me throughout the time leading up. A special thanks goes to Anna from Macquarie because she has made our visit possible even at such short notice! They have put in so much effect to make this all possible, and it’s easy for this effort to go unnoticed.
I promised to make the photos available, and here it is after the break. I’ve only included low-res photos here, but feel free to click through to get to the full quality photos. The links and resources are also after the break.
Feedback. I’d love to know what you thought about this event. Send me an email with any thoughts or comments, in particular:
- What did you get out of the day?
- Which parts did you like best (and/or didn’t like), and why?
- How can we make this event even better for next time?
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Software, USYD | Edmund Tse | 
16 Nov 2010 21:39 | 
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