Opportunistic Scheduling for OFDM Systems with Fairness Constraints
EURASIP Journal on Wireless Communications and Networking volume 2008, Article number: 215939 (2007)
We consider the problem of downlink scheduling for multiuser orthogonal frequency-division multiplexing (OFDM) systems. Opportunistic scheduling exploits the time-varying, location-dependent channel conditions to achieve multiuser diversity. Previous work in this area has focused on single-channel systems. Multiuser OFDM allows multiple users to transmit simultaneously over multiple channels. In this paper, we develop a rigorous framework to study opportunistic scheduling in multiuser OFDM systems. We derive optimal opportunistic scheduling policies under three QoS/fairness constraints for multiuser OFDM systems—temporal fairness, utilitarian fairness, and minimum-performance guarantees. Our scheduler decides not only which time slot, but also which subcarrier to allocate to each user. Implementing these optimal policies involves solving a maximal bipartite matching problem at each scheduling time. To solve this problem efficiently, we apply a modified Hungarian algorithm and a simple suboptimal algorithm. Numerical results demonstrate that our schemes achieve significant improvement in system performance compared with nonopportunistic schemes.
To access the full article, please see PDF
About this article
Cite this article
Zhang, Z., He, Y. & Chong, E.K.P. Opportunistic Scheduling for OFDM Systems with Fairness Constraints. J Wireless Com Network 2008, 215939 (2007). https://doi.org/10.1155/2008/215939