Signal Processing and Communications Laboratory

Department of Engineering

Ramji Venkataramanan

Background - Research - Publications - Teaching - Group

Position: University Lecturer

Office Location: BE3-12

Telephone: 01223 766767 (If calling from outside the UK, replace the 0 with +44)

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 in Engineering at the University of Cambridge, and a Staff Fellow at Trinity Hall. I am part of the Signal Processing and Communications Lab in the Division of Information Engineering.

I received my PhD in Electrical Engineering (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 the University of Cambridge in 2013, I held post-doctoral positions at Stanford University and Yale University. I am a Turing Fellow at the Alan Turing Institute, and an Editor of the IEEE Transactions on Communications.

Research Interests

My research interests are broadly in information theory, communications, statistical learning and inference. My publications are listed below. A more detailed description of my work can be found here.

You can find more about the information theory group here.

Publications

Preprints

  • A. Montanari and R. Venkataramanan, "Estimation of Low-Rank Matrices via Approximate Message Passing" [PDF]
  • K. Hsieh, C. Rush and R. Venkataramanan, "Spatially coupled sparse regression codes: Design and State Evolution Analysis" [PDF]
  • K. P. Srinath and R. Venkataramanan, "Empirical Bayes estimators for high-dimensional sparse vectors" [PDF]

Journal Articles

  • C. Rush and R. Venkataramanan, "The Error Probability of Sparse Superposition Codes with Approximate Message Passing Decoding", accepted to IEEE Transactions on Information Theory [PDF]
  • C. Rush and R. Venkataramanan, "Finite sample analysis of Approximate Message Passing algorithms", IEEE Transactions on Information Theory, vol. 64, no. 11, pp. 7264-7286, November 2018. [PDF]
  • R. Venkataramanan and O. Johnson, "A strong converse bound for multiple hypothesis testing, with applications to high-dimensional estimation", Electronic Journal of Statistics, Vol. 12, No. 1, pp. 1126-1149, 2018. [PDF]
  • M. Abroshan, R. Venkataramanan, and A. Guillen i Fabregas, "Coding for segmented edit channels", IEEE Transactions on Information Theory, vol. 64, no. 4, pp. 3086-3098, April 2018. [PDF]
  • A. Greig and R. Venkataramanan, "Techniques for improving the finite length performance of sparse superposition codes", IEEE Transactions on Communications vol. 66, no. 3, pp.905-917, March 2018. [PDF]
  • K. P. Srinath and R. Venkataramanan, "Cluster-seeking James-Stein estimators" IEEE Transactions on Information Theory, vol. 64, no. 2, pp. 853-874, February 2018. [PDF]
  • R. Venkataramanan and S. Tatikonda, "The Rate-Distortion Function and Excess-Distortion Exponent of Sparse Regression Codes with Optimal Encoding", IEEE Transactions on Information Theory, vol. 63, no. 8, pp. 5228-5243, August 2017. [PDF]
  • C. Rush, A. Greig, and R. Venkataramanan, "Capacity-achieving Sparse Superposition Codes with Approximate Message Passing Decoding", IEEE Transactions on Information Theory , vol. 63, no. 3, pp. 1476-1500, March 2017. [PDF]
  • R. Venkataramanan, V. N. Swamy and K. Ramchandran, "Low-Complexity Interactive Algorithms for Synchronization from Deletions, Insertions, and Substitutions", IEEE Transactions on Information Theory, vol. 61, no. 10, pp. 5670-5689, October 2015. [PDF]
  • R. Venkataramanan, T. Sarkar and S. Tatikonda, "Lossy Compression via Sparse Linear Regression: Computationally Efficient Encoding and Decoding", IEEE Transactions on Information Theory, vol. 60, no. 6, pp. 3265-3278, June 2014. [PDF]
  • R. Venkataramanan, A. Joseph and S. Tatikonda, "Lossy Compression via Sparse Linear Regression: Performance under Minimum-distance Encoding", IEEE Transactions on Information Theory, vol. 60, no. 6, pp. 3254-3264, June 2014. [PDF]
  • R. Venkataramanan, S. Tatikonda, L. Lastras-Montaño and M. Franceschini, "Rewritable storage channels with hidden state", IEEE Journal on Selected Areas in Communications, vol.32, no.5, pp. 815-824, 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]

For a complete list of publications, including my thesis and various conference papers, click here

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Teaching

Michaelmas Term 2018: 3F7 Information Theory and Coding

Lent Term 2019: 3F4 Data Transmission; 4F5 2P6 Communications

I am also a Director of Studies in Engineering at Trinity Hall.

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.

Group

  • Kuan Hsieh (PhD student)
  • Nil Fernandez-Lojo (PhD student)
  • Mahed Abroshan (PhD student, co-supervised with Prof. Albert Guillén i Fàbregas)
  • Xiaoqi (Shirley) Liu (MEng), Katie Spimpolo (MEng)

Past members:

  • Adam Greig (PhD, graduated in 2018)
  • Pavan Srinath (post-doc, 2015-18)
  • MEng: Andrew Foong (graduated 2018), Antoine Dupuis (2018), Kuan Hsieh (graduated 2016), Hafiz Azman (2015), Yujean Khapkin (2015), Ellen Davies (2014)

PhD positions: If you are interested in applying for a PhD with me and have a strong mathematical background, feel free to send an email. I will do my best to reply, but may not be able to respond quickly due to the high volume of email I receive.

Information about applying for a PhD in the Department of Engineering can be found here. Funding for PhD students is available from various sources including the Cambridge Trust for overseas students, and EPSRC doctoral training awards for UK students. Applying early is highly recommended; here are the funding deadlines.

Note: I do not have any summer internship opportunities available.

Postdoctoral Positions: There are number of fellowships available for postdoctoral research in the UK. Some of these are:

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.