An Opportunistic Packet Scheduling Algorithm for Load Balancing (LoBO) in IEEE 802.16j Multi-hop Relay-Enhanced Mobile WiMAX Network

Abstract

We consider a IEEE 802.16j multi-hop relay-enhanced Mobile WiMAX network with a full frequency-reuse capability, in which an orthogonal frequency division multiple access-based time-division duplexing frame can be asymmetrically divided into two different intervals, one for the access link to mobile stations and the other for backhaul link between the base station and the relay station (RS), while the same radio resource over the access link can be fully reused by every RS in the cell. Since a single boundary between the access and relay links is employed for the system, some access links associated with an individual RS can be either overloaded or under-loaded when the traffic load is not uniformly distributed, which incurs inefficiency in the overall resource allocation. In this paper, we propose a load-balancing opportunistic scheduling algorithm that improves the system throughput in a weighted proportional fairness sense while balancing the load for the access links shared by all RS's. The proposed algorithm dynamically determines the access-to-relay interval boundary as a part of packet scheduling, which has been shown to outperform the conventional system in which link boundary selection and packet scheduling are implemented as separate processes.