Downlink optimization of indoor wireless networks using multiple antenna systems

We compare the performance of two multiple antenna systems to be used in quality of service (QoS) supported indoor wireless networks. While a conventional array antenna system (AAS) has collocated, closely spaced antenna elements, a distributed antenna system (DAS) has largely spaced antennas over the entire area of radio coverage. To support multimedia applications requiring high bandwidth and on time delivery, we propose a set of highly spectrum efficient radio resource management algorithms. We focus on the optimization of downlink since many kinds of Internet traffic show the downlink dominance in their traffic asymmetry. To maximize the downlink throughput, we present a new transmit beamforming algorithm which can be equally applied to both DAS and AAS. The beamforming algorithm is integrated with a link scheduling algorithm that exploits the space division multiplexing (SDM) capability of multiple antenna systems to meet the QoS requirements of all terminals. Numerical examples conducted for a line of sight (LOS) environment demonstrate that a network with DAS outperforms one with AAS in terms of signal coverage and provides 40-160% higher capacity.