Signal Processing and Communications Laboratory

Department of Engineering

Ramji Venkataramanan

Background - Research - Publications - Teaching - Group

Position: University Lecturer in Digital Communications and Signal Processing

Office Location: BE3-12

Telephone: 01223 766767

E-mail: ramji.v [at] eng.cam.ac.uk

(My last name is pronounced "Ven-cut-rum-uh-nun")

Background

I am a University Lecturer (Assistant Professor) in Engineering at the University of Cambridge where I am also a Fellow of Trinity Hall. I am part of the Signal Processing and Communications Lab in the Division of Information Engineering. I received my PhD in EE(Systems) from the University of Michigan, Ann Arbor in 2008, and my undergraduate degree from the Indian Institute of Technology, Madras in 2002. Before joining Cambridge University in 2013, I held post-doctoral positions at Stanford University and Yale University.

Research Interests

My research broadly focuses on communications and information processing for networks. Particular areas of interest include network information theory, coding, statistical inference and learning. For a detailed description of my work, click here. My publications are listed below.

You can find more information about the Communications research group here. The group usually meets on Wednesdays during Term for an informal seminar. It is open to all; feel free to drop in if there is a talk of interest.

Publications

Preprints

  • R. Venkataramanan and S. Tatikonda, "The Gaussian Rate-Distortion Function of Sparse Regression Codes with Optimal Encoding", [PDF]

Journal Articles

  • R. Venkataramanan, T. Sarkar and S. Tatikonda, "Lossy Compression via Sparse Linear Regression: Computationally Efficient Encoding and Decoding", to appear in IEEE Transactions on Information Theory [PDF]
  • R. Venkataramanan, A. Joseph and S. Tatikonda, "Lossy Compression via Sparse Linear Regression: Performance under Minimum-distance Encoding", to appear in IEEE Transactions on Information Theory [PDF]
  • R. Venkataramanan, S. Tatikonda, L. Lastras-Montaņo and M. Franceschini, "Rewritable storage channels with hidden state", to appear in IEEE Journal on Selected Areas in Communication (JSAC issue on Communication Methodologies for the Next-Generation Storage Systems), vol.32, no.5, May 2014. [PDF]
  • R. Venkataramanan, S. Tatikonda and K. Ramchandran, "Achievable Rates for channels with deletions and insertions", IEEE Transactions on Information Theory, vol. 59, no.11, pp. 6990-7013, November 2013.[PDF]
  • R. Venkataramanan and S. S. Pradhan, "An Achievable Rate Region for the Broadcast Channel with Feedback", IEEE Transactions on Information Theory, vol. 59, no.10, pp. 6175-6191, October 2013. [PDF]
  • R. Venkataramanan and S. S. Pradhan, "A New Achievable Rate Region for the Discrete Memoryless Multiple-Access Channel with Feedback", IEEE Transactions on Information Theory, vol. 57, pp. 8038-8054, December 2011. [PDF]
  • R. Venkataramanan and S. S. Pradhan, "Achievable rates for multiple descriptions with feed-forward", IEEE Transactions on Information Theory, vol. 57, no.4, pp. 2270-2277, April 2011. [PDF]
  • R. Venkataramanan and S. S. Pradhan, "On computing the feedback capacity of channels and the feed-forward rate-distortion function of sources", IEEE Transactions on Communications, vol. 58, pp. 1889-1896, July 2010. [PDF]
  • R. Venkataramanan and S. S. Pradhan, "Source coding with feedforward: Rate-distortion theorems and error exponents for a general source", IEEE Transactions on Information Theory, vol. 53, pp. 2154-2179, June 2007. [PDF]
  • R. Venkataramanan and K. M. M. Prabhu, "Estimation of Frequency Offset using Warped DFT", Signal Processing, vol. 86, pp. 250-256, Feb. 2006. [PDF]

Thesis

  • R. Venkataramanan, "Information-theoretic results on communication problems with feed-forward and feedback", Ph.D Thesis, University of Michigan, 2008. [ PDF] [Slides from thesis defense]

Conference Proceedings

  • R. Venkataramanan, V. N. Swamy and K. Ramchandran, "Efficient Interactive Algorithms for File Synchronization under General Edits", Proc. of the 51st Annual Allerton Conference on Communication, Computing, and Control, Oct.. 2013. [PDF]
  • R. Venkataramanan and S. Tatikonda, "Sparse Regression Codes: Recent Results and Future Directions", Proc. IEEE Information Theory Workshop, 2013 (invited). [PDF] [ Slides]
  • R. Venkataramanan and S. Tatikonda, "Improved Capacity Lower Bounds for Channels with Deletions and Insertions", Proc. IEEE Information Theory Workshop, 2013. [PDF] [Slides]
  • R. Venkataramanan, T. Sarkar, and S. Tatikonda, "Lossy Compression via Sparse Linear Regression: Computationally Efficient Encoding and Decoding'', Proc. IEEE Int. Symp. on Information Theory (ISIT), 2013. [PDF] [Slides]
  • R. Venkataramanan and S. Tatikonda, "Sparse Regression Codes for Multi-terminal Source and Channel Coding", Proc. 50th Allerton Conf. on Communication, Control, and Computing , 2012. [PDF] [Slides]
  • R. Venkataramanan, S. Tatikonda, L. Lastras-Montaņo and M. Franceschini, "Coding Strategies for the uniform noise rewritable channel with hidden state", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2012. [PDF] [Slides]
  • R. Venkataramanan, A. Joseph, and S. Tatikonda, "Gaussian rate-distortion via sparse regression over compact dictionaries", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2012. [PDF] [Slides]
  • R. Venkataramanan, S. Tatikonda and K. Ramchandran, "Achievable rates for channels with deletions and insertions", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2011. [PDF ] [Slides]
  • R. Venkataramanan, S. Tatikonda and K. Ramchandran, "Bounds on the optimal rate for synchronization from insertions and deletions", Proc. of the Information Theory and Applications Workshop , San Diego, Feb. 2011. [PDF] [Slides]
  • R. Venkataramanan, H. Zhang and K. Ramchandran, "Interactive Low-Complexity Codes for Synchronization from Deletions and Insertions", Proc. of the 48th Annual Allerton Conference(Monticello, IL), Sep. 2010. [PDF] [Slides]
  • R. Venkataramanan and S. S. Pradhan, "Achievable Rates for the Broadcast Channel with Feedback", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2010. [PDF] [Slides]
  • A. Nazari, R. Venkataramanan , D. Krithivasan, S. S. Pradhan and A. Anastasopoulos, "Typicality graphs and their properties", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2010. [ PDF]
  • R. Venkataramanan and S. S. Pradhan, "A New Achievable Rate Region for the Discrete Memoryless Multiple-Access Channel with Feedback", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2009. [ PDF]
  • R. Venkataramanan and S. S. Pradhan, "Multiple Descriptions with Feed-forward: A Single-letter Achievable Rate Region ", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2008.
  • R. Venkataramanan and S. S. Pradhan, "On Evaluating the Rate-distortion function of sources with feed-forward and the capacity of channels with feedback", Proc. IEEE Int. Symp. on Information Theory (ISIT), 2007.
  • R. Venkataramanan and S. S. Pradhan, "Directed Information for Communication Problems with Common Side Information and Delayed Feedback/Feedforward", Proc. of the 43rd Annual Allerton Conference on Communication, Control, and Computing, Sep. 2005.
  • R. Venkataramanan and S. S. Pradhan, "Source Coding with Feed-forward" Proc. IEEE Information Theory Workshop, San Antonio, Oct. 2004.

Copyright notice: Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the copyright holders.

Teaching

Lent Term 2014: 1B Paper 6 Communications

Michaelmas Term 2013: 4F5 Advanced Communications and Coding.

I also do Part 1B Engineering supervisions for Trinity Hall: Paper 6 (Linear systems, Signal & Data Analysis, Communications) and Paper 7 (Linear Algebra and Probability)

Seminars

I organise the Signal Processing and Communications Lab seminar, held roughly once in two weeks. If you'd like to give a talk at the seminar, please send me an email.

The Communications group usually meets on Wednesdays during Term for an informal seminar. It is open to all; feel free to drop in if there is a talk of interest.

Group

I currently supervise the following students:

  • Adam Greig (Ph.D)
  • Ellen Davies (M.Eng)

Postgraduate positions: I am looking for motivated students interested in doing a PhD in the areas of information theory and coding. If you have a strong mathematical background (especially in probability) and are interested in my areas of research, feel free to email me.

Information about applying for a Ph.D in the Department of Engineering can be found here. Funding for PhD students is available from various sources, listed here. These include CHESS for students from the EU, the Cambridge Trusts for international students, and EPSRC doctoral training awards for UK students. Applying early is highly recommended since the deadlines for some scholarships can be as early as mid-October.

Note: I do not have any summer internship opportunities available. I cannot respond to enquiries about these due to the high volume of email I receive.

Postdoctoral Opportunities: There are number of fellowships available for postdoctoral research at Cambridge.

Most of these fellowships require a research proposal submitted with the support of the host organisation (Cambridge University, in this case). If you are looking for a postdoctoral position and your research interests overlap with mine, feel free to contact me. In addition to these fellowships, I may have funds available for postdoctoral positions in the future. A number of the Cambridge colleges also sponsor Junior Research Fellowships to support recent Ph.D graduates. Additional details are usually available on the individual college websites. Here is one such scheme.