Visibility State Analysis for Base Station Cooperated Micro-cellular System

Base station (BS) cooperation technologies are expected to improve user throughput at the cell edges in a cellular system [1]-[3]. Since the performance of a BS cooperation method depends on the condition of the propagation channel, especially the difference in the received signal strengths from surrounding BSs, it is important to investigate the transitions of the signal strengths at a mobile station (MS) when evaluating the performance of a BS cooperation system taking the mobility of MSs into consideration. In a micro-cellular system, the propagation loss of the BS-MS link strongly depends on the BS visibility, that is, whether BS is in line-of-sight (LOS) or non-lineof-sight (NLOS) from the MS. In this paper, we estimated the visibility state using three-dimensional maps of several areas and analyzed the statistics of the estimation results.