Exact Probabilistic Analysis of the Limited Scheduling Algorithm for Symmetrical Bluetooth Piconets

Abstract. Efficient communication in Bluetooth scatternets requires design of intra and inter-piconet scheduling algorithms, and therefore numerous algorithms have been proposed. However, due to inherent complexities of the Bluetooth Medium Access Control (MAC), the performance of such algorithms has been analyzed mostly via simulation. We show that a piconet operated according to the limited (pure round robin) scheduling algorithm is equivalent to a 1-limited polling system and utilize methods developed for the analysis of such systems to analyze this algorithm. We present exact analytic results regarding symmetrical piconets with bi-directional traffic. Our results differ from the corresponding analytical results presented as exact in [12],[13],[14],[16],[19], and [21]. We show that [14] actually presents approximate results, as it ignores important dependencies incorporated in the piconet operation model. Consequently, [14] underestimates the intra-piconet delay, in some cases by more than 50%. We also indicate that for similar reasons the analyses presented in [12],[13],[15],[16],[17],[18],[19],[20], and [21] seem to provide only approximate results