Priority-based adaptive frequency hopping for Bluetooth in multi-piconet environments

In this paper, we propose a new adaptive frequency hopping (AFH) scheme, Priority-based AFH (PAFH), for Bluetooth by introducing traffic prioritization to provide better QoS for the traffic of high priority in multi-piconet environments, especially under severe self-interference. To provide differentiated QoS, PAFH pre-classifies the whole band into non-overlapping sub hopsets that correspond to traffics of different priorities. Once the PER is higher than a predetermined threshold, the algorithm is triggered and the piconet shrinks its hopset to the corresponding sub hopset according to the traffic priority. In case of the congested condition after reducing the hopset, the piconets with a higher priority monitor their own PER periodically and have the privilege to employ a hopset restoration mechanism. Based on the PER before and after the adjustment, these piconets can change their hopsets adaptively between the sub hopset and the complete one by applying a greedy algorithm. Further, the operation of PAFH is distributed and is totally compatible with the existing specifications. Simulation results show that PAFH significantly outperforms conventional schemes.