A novel architecture and coexistence method to provide global access to/from Bluetooth WPANs by IEEE 802.11 WLANs

Bluetooth is a radio technology for wireless personal area networking (WPAN) operating in the 2.4 GHz ISM frequency band. We introduce a novel Bluetooth architecture (BlueStar) whereby selected Bluetooth devices, called Bluetooth wireless gateways (BWGs), are also IEEE 802.11 enabled so that these BWGs could serve as ingress/egress points to/from the IEEE 802.11 wireless network and thus provide access to WANs such as the Internet. We propose mitigating interference between Bluetooth and IEEE 802.11 by employing a hybrid approach of adaptive frequency hopping (AFH) and Bluetooth carrier sense (BCS) of the channels. AFH labels channels as "bad" or "good", and Bluetooth devices only access those channels in the "good" state, whereas BCS is used to avoid collision by sensing the channel prior to any transmission. By combining AFH and BCS, we minimize the effect of the worst-case interference scenario wherein both a Bluetooth and an IEEE 802.11 interface are colocated in a single device. BlueStar enables Bluetooth devices, in either a piconet or a scatternet, to access the WAN through the BWG without the need for any fixed Bluetooth access points, while utilizing the widely deployed base of IEEE 802.11 networks. We define the protocol stack employed by BlueStar as well as indicate how BWGs efficiently manage their capacity allocation through different systems. We also mathematically derive an upper bound on the number of BWGs needed in a scatternet so that uninterrupted access to all Bluetooth devices could be provided.