Improving uplink performance by macrodiversity combining packets from adjacent access points

In this paper, we suggest a postdetection strategy for combining observations made at multiple single-antenna access points in a wireless LAN, using Bluetooth as a running example. The result is a diversity gain that is analogous to a conventional antenna array, only the array is distributed throughout the network. In quasi-static Rayleigh fading and for a target packet error probability of 10^-2, the proposed technique allows a significant (18 dB) reduction in mobile transmit power when as many as six equidistant access points are used. This gain is reduced as the mobile moves closer to any one of the access points or fewer access points are used. In addition, the role of ARQ and the impact of this reception technique on throughput is investigated.