Coexistence mechanisms for Wireless Personal Area Networks (WPANs)

A Wireless Personal Area Network (WPAN) provides wireless networking among proximate devices, usually carried by an individual. This project deals with frequency hopping (FH)-based WPAN technology operating in the unlicensed spectrum, e.g. Bluetooth. The coexistence problem occurs because a WPAN (i.e. Bluetooth piconet) should share the unlicensed spectrum with other collocated WPANs as well as other proximate wireless entities. In this project we are focused on the mutual interference among collocated WPANs, termed self-interference. We have proposed two classes of distributed algorithms for mitigating the self-interference: collaborative and non-collaborative. The collaborative self-interference avoidance (SIA) algorithm is applied when the Bluetooth piconets are interconnected into a scatternet. In such case, the piconets collaborate by exchanging information via the scatternet and use this information to avoid the self-interference. The SIA algorithm yields high gains in terms of energy-efficiency in the scatternet. In the non-collaborative algorithms, we assume that the collocated WPANs are not interconnected and cannot exchange information. We introduce two algorithms for coexistence among WPANs: Dynamic Adaptive Frequency Hopping (DAFH) and Frequency Rolling (FR). The DAFH algorithm is robust towards different types of interferers. DAFH does not strictly follow the current regulation for unlicensed operation, but we argue its validity by proposing a new quantitative etiquette rule for unlicensed operation. The FR algorithm succeeds in avoiding self-interference and is designed to be compatible with the current regulation for frequency hopping in the unlicensed band. Both DAFH and FR drastically increase the average throughput of the individual WPANs. This project is a part of the Ph. D. project of Petar Popovski and a part of the activities of Hiroyuki Yomo in the FACE project. (Petar Popovski and Hiroyuki Yomo)