Uplink Pattern Optimisation and Power Control for Smart Antennas in an Indoor Infrastructure WLAN

This paper investigates uplink pattern optimisation algorithms with and without power control for a smart antenna system operating in an infrastructure Wireless Local Area Network (WLAN) following IEEE802.11a or HIPERLAN/2 standards. An indoor infrastructure WLAN scenario with multiple users communicating with an access point is modelled using a deterministic ray-tracing tool. The WLAN access point is serving multiple users simultaneously through Space Division Multiple Access (SDMA). The aim of the pattern optimisation and power control algorithm is to minimise the total power and interference to other systems while achieving target Signal to Interference plus Noise Ratio (SINR) values for each user. The target SINR is a minimum required to achieve a certain Error Rate (BER). It is shown that for high target SINR value, a null steering pattern is expected while for a low SINR target a beamsteering pattern is expected. For mixed targets, the best compromise between null steering and beamsteering is achieved.