On the size of antenna cluster in multi-user distributed antenna systems

In this paper, multi-user distributed antenna systems (DAS) with antennas deployed in clusters are studied. In order to investigate the impact of the size of antenna cluster on the system performance, the mean square access distance (MSAD), which is a function of the size of antenna cluster, is defined as a metric of the system performance. From the analysis of the asymptotic behavior of the metric, we obtain the approximate closed-form expressions for the expectation and relative variance of the MSAD. Accordingly, we find out the semi-quantitative relationship between the size of antenna cluster and the system performance. Moreover, the benefits of the DAS under different cluster size are discussed. The validity of our analysis is well verified by simulations.