Opportunistic packet scheduling algorithm for load balancing in a multi-hop relay-enhanced cellular OFDMA-TDD System

In this paper, we consider a multi-hop relay-enhanced cellular OFDMA-TDD system with the full frequency-reuse capability, in which a TDD frame can be asymmetrically divided into two different intervals, one for access link to mobile stations and the other for relay link to base station (BS)-relay station (RS) communication, while the same radio resource is fully reused by every RS in the cell. Since a single common boundary between access and relay links is employed for the system, some access link associated with an individual RS can be either overloaded or under-loaded when traffic load is non-uniformly distributed, which causes an inefficient resource allocation. This paper proposes a load-balancing opportunistic (LoBO) scheduling algorithm that improves the overall system throughput in a weighted proportional fairness manner while balancing the traffic load over the access link to be shared by all RSpsilas. The proposed algorithm dynamically determines the common access-to-relay interval boundary as a part of packet scheduling, which has been shown to outperform the conventional system in which the boundary selection and packet scheduling are implemented as the separate processes.