Indoor Distributed Antenna Systems for Multi-storey Buildings

One of the main targets of future mobile
communication systems is providing high data rate wireless transmissions and ubiquitous coverage to users located within buildings. One way to achieve this objective is to employ distributed antenna systems (DASs) in which remote antenna units (RAUs) are deployed on each floor of a building and connected to a central unit (CU) where received signals are constructively processed. However, co-channel interference caused by frequency reuse is a restraining factor as the frequency reuse distances are generally smaller in indoor radio systems. In order to design efficient and reliable indoor communication systems, a thorough understanding of the reuse distance is required. This paper investigates a number of important issues associated with indoor radio propagation and frequency reuse planning in multi-storey buildings employing DAS and presents numerical results showing the impact of reuse distance, penetration loss, pathloss exponent, and co-channel interference on spectral efficiency. System performance is evaluated in terms of average spectral efficiency over a wide range of potential mobile terminal (MT) locations for various and in-building propagation characteristics.