On the Suppression of Loops with Long Hops During Scatternet Configuration in Bluetooth MANETs

Bluetooth MANETs are ad-hoc networks constructed by Bluetooth-enabled mobile terminals. As the adjacent nodes in the networks increased, the existing fast connection establishment method between terminals generate between slave terminal in piconets. As a result, the existing fast connection establishment method generates loops. Since Bluetooth MANETs utilize a flooding-based data packet forwarding method, the loops increase the number of data packet forwarding and the processing load on the terminals. To address this problem, a method of reducing loops by controlling excessive connections between slave terminals of a piconet in Bluetooth MANETs (hereinafter referred to as an existing loop reduction method) has been proposed. While the existing loop reduction method can reduce short-hop loops to zero, however, it only considers loops consisting of three terminals and does not consider loops consisting of four or more terminals (hereinafter referred to as LongLoop). In this paper, we firstly investigated the effect of "LongLoop" on data packet forwarding in Bluetooth MANETs and proposed a new method to suppress unnecessary data packet forwarding by LongLoop. In our proposed method, we employed functions such as TTL (Time To Live) to prevent duplicate data packets from being forwarded through the LongLoop. Therefore, our proposed method is concerned that the data packet forwarding time will become longer. Through evaluation experiments, we confirmed that our proposed method can reduce unnecessary data packet forwarding by loops including LongLoop while maintaining the latency until data packets are disseminated to all terminals at the same level as before loop reduction.