Self-management in chaotic wireless deployments

Abstract

Over the past few years, wireless networking technologies have made vast forays into our daily lives. Today, one can find 802.11 hardware and other personal wireless technology employed at homes, shopping malls, coffee shops and airports. Present-day wireless network deployments bear two important properties: they are unplanned, with most access points (APs) deployed by users in a spontaneous manner, resulting in highly variable AP densities; and they are unmanaged, since manually configuring and managing a wireless network is very complicated. We refer to such wireless deployments as being chaotic.In this paper, we present a study of the impact of interference in chaotic 802.11 deployments on end-client performance. First, using large-scale measurement data from several cities, we show that it is not uncommon to have tens of APs deployed in close proximity of each other. Moreover, most APs are not configured to minimize interference with their neighbors. We then perform trace-driven simulations to show that the performance of end-clients could suffer significantly in chaotic deployments. We argue that endclient experience could be significantly improved by making chaotic wireless networks self-managing. We design and evaluate automated power control and rate adaptation algorithms to minimize interference among neighboring APs, while ensuring robust end-client performance.

Minimizing contention through cooperation between densely deployed wireless LANs

“…In our experiments in Sect. 6 we show by simulation that contention may be more than halved even in only moderately dense scenarios and that our algorithm may reduce contention by 19% compared to cooperation using standard WLAN mechanisms. Furthermore, we show that in dense deployments with only few available channels, the intuitive and frequently proposed approach to load-balance between available access points may not be optimal and that it is often preferable to even switch off some access points.…”

“…This centralized approach seems to be most appropriate for a small number of interfering domains, though. Akella et al [6] suggest algorithms that allow access points to adjust transmit power levels and rates automatically and independently from other access points. As in the previous contribution, there is no cooperation between access points with respect to channel assignments and association control.…”

“…For example, Akella et al [6] analyses data from six major U.S. cities and reports several hundred APs having ten or more neighboring access points (and occasionally even up to 80!). Obviously, the very limited number of non-overlapping operating channels in IEEE 802.11{a, b, g, n} does not aid much in alleviating the problem of contention between these networks.…”

On spectrum sharing games

“…Channel conflicts among different entities are resolved in an ad hoc manner (i.e., not in a coordinated way) or not resolved at all. This ad hoc method of channel allocation can be quite inefficient [2]. Solutions assuming that all APs use the same software have been proposed [2,21], but they do not consider the possibly selfish behavior of different entities operating the APs, and work therefore only in a cooperative environment.…”

D-Scan: Enabling Fast and Smooth Handoffs in AP-Dense 802.11 Wireless Networks

“…A client in WiFi service area is likely to receive signals from more than 10 APs most of the time [2,3]. Many of them are accessible to the clients, since they may be APs deployed by the same institution, open government proxies and voluntary individuals or shops.…”