Wireless Pers Commun (2012) 65:273–292 DOI 10.1007/s11277-011-0249-z Performance Analysis of Smart Relaying with Equal Gain Combining Nam H. Vien · Ha H. Nguyen · Tho Le-Ngoc Published online: 3 March 2011 © Springer Science+Business Media, LLC. 2011 Abstract Relaying communications has been proposed as a way to provide spatial diver- sity. In general, one is interested in a relaying system that can achieve the maximal diversity order with a low system complexity. One enabling technique is equal gain combining (EGC) and its application in relaying systems is the main focus of this paper. In particular, the techniques of EGC and smart relaying are combined in the decode-and-forward (DF) pro- cessing method. It is shown that for a system with one relay and M-ary phase-shift-keying ( M-PSK) modulation, maximal diversity orders of 2m and 2 are achieved over Nakagami-m and Hoyt fading environments, respectively. With K relays, simulation results suggest that the corresponding diversity orders are m( K + 1) and ( K + 1). Keywords Relaying communications · Adaptive transmission · Decode-and-forward · Diversity order · Equal gain combining · Nakagami-m fading · Hoyt fading 1 Introduction Recently, relaying communications has drawn much attention due to its ability to exploit spatial diversity while avoiding the need of co-located antenna arrays (see, for example [1–4] and [5]). If properly designed, the system can achieve a diversity order up to the number of diversity paths, what can be referred to as the maximal diversity order [6]. To exploit N. H. Vien (B ) · H. H. Nguyen Department of Electrical and Computer Engineering, University of Saskatchewan, 57 Campus Dr, Saskatoon, SK S7N 5A9, Canada e-mail: nam.vien@usask.ca H. H. Nguyen e-mail: ha.nguyen@usask.ca T. Le-Ngoc Department of Electrical and Computer Engineering, McGill University, 3480 University St., Montreal, Quebec H3A 2A7, Canada e-mail: tho@ece.mcgill.ca 123