Performance Analysis of Maximal Ratio Diversity Receivers over Generalized Fading Channels

Diversity reception, is an efficient communication receiver technique for mitigating the detrimental effects of multi-path fading in wireless mobile channels at relatively low cost. Diversity combining is the technique applied to combine the multiple received copies of the same information bearing signal into a single improved signal, in order to increase the overall signal-to-noise ratio (SNR) and improve the radio link performance. The most important diversity reception methods employed in digital communication receivers are maximal ratio combining (MRC), equal gain combining (EGC), selection combining (SC) and switch and stay combining (SSC) (Simon&Alouini, 2005). Among these well-known diversity techniques, MRC is the optimal technique in the sense that it attains the highest SNR of any combining scheme, independent of the distribution of the branch signals since it results in a maximum-likelihood receiver (Simon & Alouini, 2005). Of particular interest is the performance analysis of MRC diversity receivers operating over generalized fading channels, as shown by the large number of publications available in the open technical literature. The performance of MRC diversity receivers depends strongly on the characteristics of the multipath fading envelopes. Recently, the so-called η-μ fading distribution that includes as special cases the Nakagami-m and the Hoyt distribution, has been proposed as a more flexible model for practical fading radio channels (Yacoub, 2007). The η-μ distribution fits well to experimental data and can accurately approximate the sum of independent non-identical Hoyt envelopes having arbitrary mean powers and arbitrary fading degrees (Filho & Yacoub, 2005). In the context of performance evaluation of digital communications over fading channels this distribution has been used only recently. Representative past works can be found in (Asghari et al., 2010; da Costa & Yacoub, 2007; 2008; Ermolova, 2008; 2009; Morales-Jimenez & Paris, 2010; Peppas et al., 2009; 2010). For example, in (da Costa & Yacoub, 2007), the average channel capacity of single branch receivers operating over η-μ channels was derived. In (da Costa & Yacoub, 2008), expressions for the moment generating function (MGF) of the above mentioned channel were provided. Based on these results, the average bit error probability (ABEP) of coherent binary phase shift keying (BPSK) receivers operating over η-μ fading channels was obtained. Furthermore, in (da Costa & Yacoub, 2009), using an approximate yet highly accurate expression for the sum of identical η-μ random variables, infinite series representations for the Outage Probability and ABEP of coherent and non Performance Analysis of Maximal Ratio Diversity Receivers over Generalized Fading Channels