Implementation of an IEEE 802.11 link available bandwidth algorithm to allow crosslayering

Abstract

With the popularity and wide adoption of IEEE 802.11 equipment, wireless networks are being used in an increasing number of applications. Wireless links brings new challenges to communications protocols since link quality is unpredictable. To cope with this problem, many recent research proposals have employed cross-layering design. Often, the MAC layer is assumed to provide link quality metrics. Existing IEEE 802.11 radios and drivers do not provide detailed link quality metrics, which restrained a lot of cross-layering work to simulation environment. In this paper, we propose an algorithm that measures and computes link quality metrics inside IEEE 802.11 MAC so that it provides detailed link quality information to other layers of the protocol stack. Among other things, we implemented an algorithm that provides the available bandwidth to each neighbor node in an ad hoc network. This could be used in a number of scenarios to achieve work in the area of cross-layer design in real test beds. Typically, such work has been constrained to simulation or emulation environments due to the lack of link quality metrics provided by IEEE 802.11 MAC drivers.