Capacity analysis of generalized distributed antenna systems using approximation distributions

Compared to the central antenna system (CAS), the distributed antenna system (DAS) improves the communication performance greatly because of the macro-diversity and the micro-diversity. However, the channel between the mobile terminal and a remote access unit (RAU) in the DAS is a composite fading channel, which makes it be difficult to achieve a closed form expression in capacity analysis. In this paper, Patnaik¿s and Pearson¿s methods are employed to achieve approximation probability distribution function (PDF) of the channel, by which the ergodic capacity of the generalized DAS (GDAS) is achieved easily. Analysis and simulations show that both the two methods can achieve satisfying results of the channel capacity, which are more accurate than that of the commonly used Jensen inequality.