The design of broadband wireless communications presents considerable challenges. The propagation conditions can be very hostile (e.g., highly dispersive channels and/or deep fading or shadowing effects). This is especially true for systems operating in mm-wave conditions, where one must rely in LoS and/or reflected rays. Moreover, these systems are expected to have power and spectral efficiencies, together with high QoS requirements. There are also implementation complexity constraints, especially at the mobile terminals.

Prefix-assisted block transmission techniques combined with frequency-domain detection are known to be suitable for high rate transmission over severely time-dispersive channels. The most popular modulations based on this concept are OFDM (Orthogonal Frequency-Division Multiplexing) and SC-FDE (Single-Carrier with Frequency-Domain Equalization). However, the severe propagation conditions in multiuser wireless systems make it likely that a non-negligible fraction of the transmitted packets will be lost, either due to deep fading/shadowing effects or due to collisions in the MAC (Medium Access Control) phase.

The traditional approach to cope with lost packets is to drop them and ask for its retransmission. However, even packets with a large number of bit errors have useful information on the transmitted blocks that can be employed to improve the detection performance. To take advantage of this, we need to employ a cross-layer approach combining PHY, MAC and LLC layer aspects to cope with lost packets. In this talk we show how we can design powerful cross-layer network diversity techniques specially designed for broadband wireless systems employing block transmission techniques combined with frequency domain detection.

Biography:

Rui Dinis received the Ph.D. degree from IST, Technical University of Lisbon, Portugal, in 2001 and the Habilitation in Telecommunications from FCT, Nova University of Lisbon (UNL) in 2010 where he is a Full Professor. Rui Dinis is also researcher at IT (Instituto de Telecomunicações). During 2003 he was a visiting professor at Carleton University, Ottawa, Canada.

Rui Dinis is an IEEE ComSoc Distinguished Lecturer and an IEEE VTS Distinguished Speaker. He is or was editor at several major IEEE journals (IEEE TWC, TCOM, TVT and OJ-COMS) and at Elsevier Physical Communication and Hindawi ISRN Communications and Networking. He was also a guest editor for multiple special numbers in several journals.

He was involved in the organization of IEEE conferences, namely several VTC and GLOBECOM, and is a member of several technical committees of IEEE Communications Society.

Rui Dinis has been actively involved in several international research projects in the broadband wireless communications area. He was involved in pioneer projects on the use of mm-waves for broadband wireless communications and his main research activities are on modulation and transmitter design, nonlinear effects on digital communications and receiver design (detection, equalization, channel estimation and carrier synchronization), with emphasis on frequency-domain implementations, namely for MIMO systems and/or OFDM and SC-FDE modulations. He is also working on cross-layer design and optimization involving PHY, MAC and LLC issues, as well as indoor positioning techniques.

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