题目一：Lattice Reduction Aided Detection: A Tutorial Revisit

内容简介：The lattice formulation of signal detection problems has led to the so-called lattice-reduction-aided detectors. For MIMO detection over a quantized Rayleigh fading channel with a finite precision ADC, the full diversity order can be achieved by use of the so-called LLL-reduction-aided successive interference cancellation (SIC) detector.  which has a worst-case complexity being quartic in the MIMO dimension. This is a favorable alternative to the optimal maximum likelihood detector which has an exponential complexity. The LLL (Lenstra-Lenstra-Lovasz) lattice reduction algorithm, which is a famous tool in the computational number theory, has been one of the most widely used algorithms in the area of cryptography. This talk provides a tutorial revisit to the key concepts behind lattice reduction.

题目二：Lattice Reduction Aided Detection: Two Variations of the LLL algorithm

内容简介：In this presentation, we show how the idea of sorting can be integrated into the classical LLL algorithm enabling the complexity to be halved, approximately. The resultant algorithm is called the joint sorting and reduction (JSAR) algorithm. Moreover, when the LLL reduction algorithm is seriously truncated or early terminated, the novel JSAR based LLL-SIC significantly outperform and appears to achieve possibly higher (but still suboptimal) diversity order than the conventional counterpart at low-to-moderate bit-error-rates. This suggests that it can be applied advantageously to MIMO systems with a strict delay constraint. Inspired by the JSAR result, we further propose the so-called partial reduction algorithm that only performs lattice reduction for the last several, weak MIMO substreams and sorting for the remaining streams. By tuning the block size of the partial reduction (hence the complexity), it can achieve a variable diversity order, hence offering a graceful tradeoff between performance and complexity for SIC-based MIMO detection. Among other consequences, our result leads to a cubic worst-case complexity MIMO detector with a diversity order greater than 1, which outperforms the VBLAST detector with the same complexity order.

报告人：香港科技大学  缪伟豪（Wai Ho Mow）  副教授

报告人简介：Wai Ho Mow received his Ph.D. degree in information engineering from the Chinese University of Hong Kong in 1993. From 1997 to 1999, he was with the Nanyang Technological University, Singapore. He has been with the Hong Kong University of Science and Technology (HKUST) since 2000. His research interests are in the areas of communication, coding, and information theory. He pioneered the lattice approach to signal detection problems, including sphere decoding and complex lattice reduction-aided detection. He unified all known constructions of perfect roots-of-unity (aka CAZAC) sequences, which have been widely used as communication preambles and radar signals, and also settled McEliece’s open problem on minimax aperiodic correlation for equi-energy sequence sets and for polyphase sequence pairs. He published 1 book, coauthored over 200 technical publications, among which he is the sole author of over 40, and filed over 30 patents. The joint works with his postdoc and students won the top prizes of 10+ paper/technology competitions, including the 2014 HK U-21 IoT Gold Award for Revolutional Concept, the Best Paper Award of 2013 and 2016 Asia-Pacific Communications Conference, and the Best Mobile App Award at ACM MobiCom'2013. A novel picture-embedding 2D barcode, PiCode, developed by the HKUST Barcode Group under his leadership was highlighted as one of the four local innovations in the 2015 International IT Fest, a flagship event organized by the Office of Government Information Officer, Hong Kong. He was the program chair of SETA’2018 and five other conferences, the financial chair of ISIT’2015, and a past chair of the Hong Kong Chapter of the IEEE Information Theory Society. He is currently an Editor of the IEEE Transactions on Wireless Communications and was a Guest/Associate Editor for five special sections of the IEICE Transactions on Fundamentals. He was an industrial consultant for Huawei, ZTE, and Magnotech Ltd. He is a member of the Electronics and Telecommunication Training Board, Vocational Training Council, appointed by Secretary for Education, and is a past member of the Radio Spectrum Advisory Committee, Office of the Telecommunications Authority, the Hong Kong S.A.R. Government.

时  间：2018年11月28日（周三）下午3：30始

地  点：南海楼124室

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