A scheduler for the downlink of multi-user wireless systems with frame aggregation

This paper addresses the MAC layer packet scheduling in wireless systems with frame aggregation that allows the base station to transmit two or more data streams to different users simultaneously. We also consider the scheduler with support of users' quality of service (QoS) requirements. We first formulate the scheduling problem with frame aggregation into a knapsack problem that is shown NP hard. Then we pro pose a simple approximation algorithm (LUUF) based on the unit urgency concept. Our analysis shows that the complexity of LUUF is O(n log n) and it achieves an approximation ratio of F '/ Fmax. We then show that in practice the complexity can be further reduced to O(n) and the approximation ratio can be made very near to 1, which make LUUF a promising candidate for wireless systems that support frame aggregation. © 2008 IEEE