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Adam Williamson |
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I am a Ph.D. student in the UCLA Department of Electrical Engineering, working in the Communication Systems Laboratory with Professor Rick Wesel. |
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Much of my research has focused on the benefits of feedback in communication systems. In addition, I'm interested in applying information-theoretic concepts and communication system design techniques to a variety of other problems, such as coding for storage. In particular, I've explored system-level approaches to optimize the lifetime of flash memory devices and techniques to mitigate cell-to-cell interference in flash memory. In my feedback work, I'm investigating how feedback-based incremental redundancy allows systems to achieve throughputs close to capacity at short blocklengths (i.e., in several hundreds of bits rather than several thousand that have traditionally been required for fixed-length block codes). I'm interested in both analyzing this finite-blocklength rate theoretically for a variety of channels and demonstrating practical codes that match the theory. For short blocklengths, it becomes especially important to account for the cost of the error detection mechanism, so I'm also exploring various methods of error detection in the incremental redundancy setting. One approach is to use the reliability output Viterbi algorithm (ROVA) to determine when to terminate transmission of a variable-length code (such as punctured convolutional codes), as described in my paper at ISIT 2013. For more details about my feedback work, see the following paper and slides:
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Conference Papers (top)
- A. R. Williamson, T.-Y. Chen, and R. D. Wesel, "Reliability-based Error Detection for Feedback Communication with Low Latency".
IEEE Int. Symp. Inf. Theory (ISIT), Istanbul, Turkey, July 7 - 12, 2013.
- T.-Y. Chen, A. R. Williamson, and R. D. Wesel, "Variable-length Coding with
Feedback: Finite-length Codewords and Periodic Decoding".
IEEE Int. Symp. Inf. Theory (ISIT), Istanbul, Turkey, July 7 - 12, 2013. Available at http://arxiv.org/abs/1301.7464.
- R. D. Wesel, T. Zhang, A. R. Williamson, T.-Y. Chen, and K. Vakilinia, "Dynamic Voltage Allocation Based on Mutual Information for NAND Flash Memory". Non-Volatile Memories Workshop (NVMW), San Diego, CA, March 4 - 5, 2013.
- A. R. Williamson, T.-Y. Chen, and R. D. Wesel, "Firing the Genie: Two-Phase Short-blocklength Convolutional Coding with Feedback". IEEE Inf. Theory and Applications (ITA) Workshop, San Diego, CA, USA, February 12 - 16, 2013. [pdf]
- A. R. Williamson, T.-Y. Chen, and R. D. Wesel, "A Rate-Compatible Sphere-Packing Analysis of Feedback Coding with Limited Retransmissions".
IEEE Int. Symp. Inf. Theory (ISIT), Cambridge, MA, USA, July 1 - 6, 2012. Available at http://arxiv.org/abs/1202.1458.
Talks (top)
- A. R. Williamson, T.-Y. Chen, and R. D. Wesel, "High Throughput with Low Latency: The Analysis and Design of Rate-Compatible Codes for Gaussian Channels with Feedback".
UCLA Electrical Engineering Annual Research Review, Los Angeles, CA, USA, December 4, 2012.
- A. R. Williamson, T.-Y. Chen, and R. D. Wesel, "A Rate-Compatible Sphere-Packing Analysis of Feedback Coding with Limited Retransmissions".
IEEE Int. Symp. Inf. Theory (ISIT), Cambridge, MA, USA, July 1 - 6, 2012. Available at http://arxiv.org/abs/1202.1458.
Posters (top)
- A. R. Williamson and R. D. Wesel, "An Improved Lower Bound on Rate for Variable-length Codes with Active Feedback". North American School of Information Theory, West Lafayette, IN, USA, June 3 - 7, 2013.
Contact Information:
adamroyce - ucla - edu