Performance Analysis of In-Building Distributed Antenna Systems with Frequency Reuse

A major challenge in the design of future mobile communication systems is providing high data rate wireless transmissions and ubiquitous coverage to users located within buildings. One way to solve this problem is to employ distributed antenna systems (DASs) located indoors to provide coverage and high data rates. However, co-channel interference caused by frequency reuse is a restraining factor as the frequency reuse distances are generally smaller in in-building DAS. In order to design efficient and reliable indoor communication systems, knowledge of the reuse distance is required. This paper investigates the performance of an in-building DAS where remote antenna units (RAUs) are deployed on each floor of the building and connected to a central unit (CU) where received signals are constructively processed. Frequency reuse is employed among floors of the building and the impact of co-channel interference on system performance is investigated by using a propagation channel model derived from multi-floor, inbuilding measurement results. The system exploits radio propagation path loss characteristics in order to reduce the impact of co-channel interference and hence increase the spectral efficiency. System performance is evaluated in terms of average spectral efficiency over a wide range of potential mobile terminal (MT) locations, various reuse distances and in-building propagation characteristics