Frequency Selective OFDMA Scheduler with Limited Feedback

Abstract

Orthogonal Frequency Division Multiple Access (OFDMA) is the preferred multiple access scheme for future broadband cellular systems as it provides high spectral efficiency. The choice of OFDMA scheduler and the amount of channel quality feedback from users together determine the achievable throughput and fairness. Channel quality reporting by all active users across the entire carrier bandwidth may result in significant uplink overhead. This paper discusses the performance of two possible OFDMA schedulers based on the class and channel condition weighted proportionally fair scheduler. The impact of different scheduler parameters are investigated. The paper then analyzes the performance of the top-M scheme, which is a candidate channel quality overhead reduction proposal being discussed in 3GPP Long Term Evolution. It is shown that the top-M scheme, with significantly lower uplink overhead, provides similar performance as the case where the network has complete channel quality information.

Resource Allocation for Multi-User OFDMA-Based Wireless Cellular Networks

“…Thus, to find the 'best' chunk(s) for each user, several solutions may be considered. In this section, we consider two common chunk allocation algorithms whose principles are derived from (Ramachandran et al, 2008):…”

Holistic Approach for Future Energy Efficient Cellular Networks

“…Priority is granted indeed to UEs selected by standard MCI 'matrix-based chunk allocation' described in (Ramachandran et al, 2008) with l k;n ðiÞ ¼ R k;n ðiÞ. Actually, the matrix contains the metrics l k;n ðiÞ of all possible user-chunk pairs (only for previously unscheduled chunks), where at time i, UE k has a metric for chunk n which is given by l k;n ðiÞ ¼ R k;n ðiÞ.…”

A QoS-Aware Resource Allocation Scheme with Limited Feedback in Downlink OFDMA Systems

“…This is the main idea of the top-M scheme being considered in 3GPP LTE. The value of M is same for all UEs and is signaled by BS [7].…”