ST-MRC Based System Capacity Analysis in Distributed Antenna Systems
Lingling Cao, Jin‐Yuan Wang, Min Zhong Feng, Ming Wei Sheng, Xiu-Xiu Xie · International Conference on Electronics, Communications and Control · 2012
Based on selective transmission (ST) and maximal ratio combining (MRC) schemes, this paper focuses on the analysis of downlink system capacity in distributed antenna systems (DAS) over composite channels. Firstly, this paper establishes a composite channel model which takes path loss, lognormal shadowing and Rayleigh fading into account. Then, the probability density function (PDF) of the output signal to-noise ratio (SNR) is derived after MRC at the receiver. Moreover, the distribution of the output SNR is approximated by a lognormal distribution. After that, by making use of ST scheme, an approximate expression of the capacity for a mobile station (MS) over a given position is derived. Further, considering the distribution of MSs in the system, a closed-form expression of the system capacity is obtained. Numerical results show that the closed-form expression can provide sufficient precision for evaluating the system capacity performance of DAS.