Exploiting the full potential of multi-AP diversity in centralized WLANs through back-pressure scheduling

Centralized WLANs widely deployed in enterprise environment or university campus often have high density of Access Point (AP). The high density leads to multi-AP diversity, which brings possibility to improve network performance. Previous studies have proposed different schemes to exploit multi-AP diversity, however, these schemes are all based on heuristic and cannot guarantee an optimal exploitation of multi-AP diversity. In this paper, we propose a Theory Based Centralized Scheduling (TBCS) to exploit the full potential of multi-AP diversity. TBCS is based on the well-known back-pressure scheduling. Although back-pressure scheduling is proved to be throughput-optimal, most of previous studies are purely theoretical. To make a practical use of the theoretical back-pressure scheduling, we design new mechanisms in TBCS to handle the problem caused by the wired/wireless mixed scenario of centralized WLANs and to synchronize the scheduling. We evaluate TBCS through NS-2 simulations and show that compared with previous methods, TBCS can support the largest capacity region and greatly improves the throughput of a network.