The University of British Columbia

In this paper, some analytical results for selection diversity over Nakagami fading channels are presented. In particular, a closed-form expression for the probability density function (pdf) of the general order statistics of a set of independent but not necessarily identically distributed (i.n.d.) Gamma random variables is derived. Subsequently, closed-form expressions for the corresponding cumulative distribution function (cdf), moment generating function (MGF), as well as arbitrary moments are presented. The usefulness of the results is illustrated in the context of adaptive modulation and coding (AMC) with multicode transmission, which is one of the key components of the High Speed Downlink Packet Access (HSDPA) of the Wide-band Code-Division Multiple Access (WCDMA) standard.