Distributed Opportunistic Scheduling With <roman>QoS</roman> Constraints for Wireless Networks With Hybrid Links

Abstract

Opportunistic scheduling for a wireless network with hybrid links is studied in this paper. Specifically, two link types are considered: a link of the first type always has a much lower transmission rate than a link of the second type. To avoid starvation in the first type of links, two link types must be treated differently in opportunistic scheduling, and quality of service (QoS) constraints, such as maximum delay or minimum throughput, must be imposed on the first link type. Considering QoS constraints, a distributed opportunistic scheduling scheme is derived based on the optimal stopping theory. Two scenarios are considered for the QoS-oriented opportunistic scheduling scheme. In the first scenario, all links within the same link type follow the same rate distribution. Thus, QoS constraints are imposed on the entire link type. In the second scenario, links of the first type follow heterogeneous rate distributions. Thus, QoS requirements need to be imposed on links with the worst performance. Performance results show that the new opportunistic scheduling scheme outperforms the existing ones in most scenarios.