**On MU-MIMO Precoding Techniques for WiMAX**

Elsadig Saeid, Varun Jeoti and Brahim B. Samir

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/56034

In this book, a collection of selected papers is presented, which covers several aspects of the WiMAX technology, investigated by specialists working in universities and research centres

Chapter 1 is focused on multiuser (MU) multiple input multiple output (MIMO) diversity techniques. It provides a comprehensive overview of various MIMO strategies and a critical discussion on the recent research in multiuser MIMO communications with emphasis on the design of precoders. State-of-the-art in research on MU-MIMO precoding and multi-cell processing is presented. A new precoder design and its application in WiMAX setting is also

In chapter 2 the issue of the high peak-to-average power ratio (PAPR) that affects WiMAX is investigated, with particular reference to the adoption of companding as a PAPR mitigation strategy. Impairments from nonlinear distortion at the transmitter, multipath and noise are

Chapter 3 deals with the adoption of mesh architectures within WiMAX, and provides an overview of the main challenges of the WiMAX mesh mode, with a focus on routing proto‐

Chapter 4 investigates the handover mechanism, with particular reference to the cell selec‐ tion scheme. A multi-criteria selection scheme is proposed, based on the experienced carrierto-interference plus noise ratio, the required bandwidth and the expected congestion delay.

In chapter 5 the issue of coordinated authentication in a heterogeneous network environ‐ ment is investigated. A Coordinated Robust Authentication (CRA) Mechanism is presented,

Finally, Chapter 6 reviews the Multicast and Broadcast re-keying Algorithm (MBRA) of IEEE 802.16e, that ensures the confidentiality of communications. The operational efficiency,

Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi".

**Gianni Pasolini, Ph.D., Researcher.**

University of Bologna, Italy

cols and the effect of quality of service mechanisms on scenarios with mobile clients.

with the ability to use a single set of credentials with any network.

scalability and 1-affects-n phenomenon are discussed.

all over the world.

VIII Preface

provided.

considered.
