A wireless local area network employing distributed radio bridges

Abstract

This paper presents a novel distributed wireless local area network (WLAN) architecture, where each wireless terminal (WT) accesses a backbone local area network (LAN) segment via multiple radio bridges (RB's). We introduce a self-learning routing algorithm for the RB's, which automatically adapts to changes in terminal locations, and prevents multiple copies of each data frame from being forwarded over the backbone LAN segment. The distributed WLAN architecture eases the management of network topological changes and terminal mobility, compared to centralized cellular architectures. We consider the use of direct-sequence spread-spectrum (DS/SS) signaling and the slotted Aloha medium access control (MAC) protocol over the wireless links, with multiple uplink receivers and downlink transmitters at the RB's for each MAC frame. Simulation results for the uplink show that the multi-receiver site diversity and the capture effect of DS/SS signaling effectively combat multipath and multiaccess interference, resulting in high throughput capacity and stable operation for the channel. Under overload traffic, the system is able to maintain a high level of throughput with bounded delays. It is shown that the use of multiple receiver reduces the access fairness problem for WT's at different locations caused by the near-far effect.