Information and System Group

April 2013

No Date Title Speaker Presentation Discussion
1 2013-04-11 Efficient Design and Decoding of Polar Codes Jeongmin  (PDF)  
Polar codes are shown to be instances of both generalized concatenated codes and multilevel codes. It is shown that the performance of a polar code can be improved by representing it as a multilevel code and applying the multistage decoding algorithm with maximum likelihood decoding of outer codes. Additional performance improvement is obtained by replacing polar outer codes with other ones with better error correction performance. In some cases this also results in complexity reduction. It is shown that Gaussian approximation for density evolution enables one to accurately predict the performance of polar codes and concatenated codes based on them.
2 2013-04-18 Aliasing-Free Wideband Beamforming Using Sparse Signal Representation  J. Oliver    (PDF)
This paper considers the use of sparse signal representation for the wideband direction of arrival (DOA) or angle of arrival estimation problem. In particular, this paper discusses about the two ambiguities, namely, spatial and algebraic aliasing that arise in wideband-DOA. The authors of the paper suggest procedures to avoid the aliasing using multiple measurement vector and multiple dictionaries.