DSASync: Managing End-to-End Connections in Dynamic Spectrum Access Wireless LANs

摘要

Wireless LANs (WLANs) have been widely deployed as edge access networks that provide the important service of Internet access to wireless devices. Therefore, performance of end-to-end connections to/from such WLANs is of great importance. The advent of Dynamic Spectrum Access (DSA) technology is expected to play a key role in improving wireless communication. With DSA capability, WLANs opportunistically access licensed channels in order to improve spectrum-usage efficiency and provide better network performance. In this paper, we identify the key issues that impact end-to-end connection performance when a DSA-enabled WLAN is integrated with the wired cloud. We propose a new network management framework, called DSASync, to mitigate the identified performance issues. DSASync achieves this objective by managing the connections at the transport layer as a third-party supervisor and targets both TCP streams and UDP flows. DSASync requires no modifications to the network infrastructure or the existing network stack and protocols while ensuring transport protocol (TCP or UDP) semantics to be obeyed. It mainly consists of a combination of buffering and traffic-shaping algorithms to minimize the adverse side-effects of DSA on active connections. DSASync is evaluated using a prototype implementation and deployment in a testbed. The results show significant improvement in end-to-end connection performance, with substantial gains on QoS metrics like goodput, delay, and jitter. Thus, DSASync is a promising step toward applying DSA technology in consumer WLANs.