Preface

**Section 6 Physical Layer Security for Multi-User MIMO**

Chapter 6 **Physical Layer Security for Multiuser MIMO**

Giovanni Geraci and Jinhong Yuan

**Section 7 User Selection in Multi-User MIMO Systems 157**

Chapter 7 **Lattice Reduction-Based User Selection in Multiuser**

Qiaoyu Li, Ying Li, Lin Bai and Jinho Choi

**Communications 139**

**VI** Contents

**Communications 141**

**MIMO Systems 159**

Multiple Input Multiple Output (MIMO) technology is a viable way to achieve high data rates for wireless communications. Previous researches have been done on the theoretical front and has been validated in practice. MIMO systems exploit both the diversity gain and the spatial multiplexing gain to allow for a substantial increase of spectral efficiency and higher data rates.

Recent focus is on extending the benefits of MIMO technology to multi-user systems. It is shown that Multi-User Multiple-Input Multiple-Output (MU-MIMO) systems achieve high data rates envisioned for 3G (3rd Generation) standards and other standards beyond 3G such as 3rd Gen‐ eration Partnership Project Long Term Evolution (3GPP LTE) and LTE-Advanced.

Chapter 1 will give information about the fundamentals of multi-user MIMO communica‐ tion. The chapter will consider the benefits of multiple antenna systems. MU-MIMO systems will be introduced and main topics including system configuration, fields of applications, capacity region and precoding techniques will be examined.

Chapter 2 will present a literature survey of the single-cell opportunistic beamforming (OBF) /random beamforming (RBF). Recent investigations on multi-cell RBF systems will be introduced and achievable rates of multi-cell RBF in finite-SNR regime will be reviewed. Different configurations including multi-cell MIMO-BC system, MISO/MIMO RBF schemes and single-cell OBF/RBF will be presented.

Chapter 3 will examine the LTE and LTE-Advanced framework. This chapter will consider the interference cancellation in multi-user scenario and low-complexity interference-aware receiver structure will be discussed.

Chapter 4 will be dedicated to multi-user interference suppression. Distributed antenna net‐ work (DAN) and conventional cellular system with centralized antennas at the BS (CAN sys‐ tem) will be considered. Single-carrier (SC) frequency domain adaptive antenna array (SC-FDAAA) for the uplink transmission will be performed for multi-user interference suppression and performances of both DAN SC-FDAAA and CAN SC-FDAAA will be evaluated.

Chapter 5 will consider solutions for the incorporation of multi-user capabilities in IEEE 802.11n/ac for WLAN systems. This chapter will be dedicated to the study of multi-user MAC layer protocols. Multi-user mechanism included in the 802.11ac draft standard and the additional challenges that arise from simultaneous transmissions will be examined.

Chapter 6 will survey the physical layer security for multi-user MIMO communications and suboptimal low-complexity transmission schemes will be discussed within challenging net‐ works.

Chapter 7 will be dedicated to user selection based error probability of MIMO detector in multi-user MIMO system. Low complexity greedy user selection approach with suboptimal Lattice Reduction (LR)-based detector will be studied.

This book focuses on multi-user MIMO communication and covers a collection of the major topics and issues in multi-user MIMO systems. « Recent Trends in Multi-user MIMO Com‐ munications » provides a tutorial overview of the latest technologies and research keys re‐ lated to multi-user communication.

The target audience of this book comprises researchers, Ph.D. students, academicians and pro‐ fessionals working in the field of Signal Processing and Multiple Antenna Systems. It provides an interdisciplinary guide that can help the reader about the multi-user MIMO communication.

> **Maha BEN ZID** National School of Engineering of Le Mans (ENSIM) France

**Section 1**

**Fundamentals of Multi-User MIMO**

**Communication**
