Practical channel state aware and cooperative packet scheduling disciplines for coordinating colocated Bluetooth and IEEE 802.11b devices

Abstract

Attempts to satisfy the demand for ubiquitous communications have resulted in a proliferation of hand-held short range communication devices based on the ISM (Industrial, Scientific, Medical) band technologies, most notably Bluetooth and IEEE 802.11b. However, coexistence between Bluetooth and IEEE 802.11b has become a critical issue that could severely hinder the performance achieved by user devices. In this study we performed a detailed implementation of a Linux based network access point (NAP), in which Bluetooth and IEEE 802.11b interfaces are colocated. Such an NAP is crucial in supporting "hot-spot" systems targeted to serve nomadic users carrying either a Bluetooth or an IEEE 802.11b device. Specifically, the goal of our study is to investigate the efficacy of a software-based interference coordination approach, through a detailed actual implementation so as to identify system issues which are difficult to obtained by simulations. We considered a wide range of common scheduling algorithms as the possible solutions in a Linux environment to estimate the interference effects as viewed from the network layer perspective. Upon our investigation, two wireless scheduling algorithms based on Channel State Independent Fair Queueing (CIFQ) were implemented in Linux to test their empirical performance under this NAP application. Finally, guided by our practical findings, we proposed and implemented two new packet scheduling algorithms in Linux to provide the best trade-offs to colocated Bluetooth and IEEE 802.11b traffics, as well as QoS support for different applications. Our results show that dynamic priorities and cooperative transmissions between Bluetooth and IEEE 802.11b traffic can effectively protect both interfaces from interference. We also compared our proposed scheme with two MAC layer approaches. © 2007 Elsevier B.V. All rights reserved.