Institute of Information Science, Academia Sinica

This talk addresses some techniques for improving the throughput performance of wireless networks. We address the problem of coexistence, a key issue in effective unlicensed bands usage, among devices of wireless local area networks (WLANs) and wireless personal area networks (WPANs). The techniques to be presented include 1) A developed analytical model that can accurately model the interference phenomena between WLANs and WPANs, and non-collaborative solutions for WLAN and WPAN. For WLAN, we propose a dynamic fragmentation (DF) mechanism to optimize the packet length such that    Wi-Fi devices have better chance to avoid the interference caused by Bluetooth devices. For WPAN, we propose an adaptive hopset frequency hopping (AHFH) mechanism to avoid the interference from coexisting WLAN as well as the self-interference from collocated Bluetooth piconets; 2) To resolve the problem of spectrum scarcity, we propose a statistic channel allocation MAC (SCA-MAC) and a dynamic spectrum access MAC (DSA-MAC). Both protocols can exploit the “spectrum hole” on licensed bands to minimize their interference on incumbent users and also reduce collisions with other cognitive radio (CR) nodes.