Joint Performance Analysis of Channel Quality Indicator Feedback Schemes and Frequency-Domain Scheduling for LTE

Donthi, Sushruth N and Mehta, Neelesh B (2011) Joint Performance Analysis of Channel Quality Indicator Feedback Schemes and Frequency-Domain Scheduling for LTE. In: IEEE Transactions on Vehicular Technology, 60 (7). pp. 3096-3109.

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Abstract

Frequency-domain scheduling and rate adaptation enable next-generation orthogonal frequency-division multiple access (OFDMA) cellular systems such as Long-Term Evolution (LTE) to achieve significantly higher spectral efficiencies. LTE uses a pragmatic combination of several techniques to reduce the channel-state feedback that is required by a frequency-domain scheduler. In the subband-level feedback and user-selected subband feedback schemes specified in LTE, the user reduces feedback by reporting only the channel quality that is averaged over groups of resource blocks called subbands. This approach leads to an occasional incorrect determination of rate by the scheduler for some resource blocks. In this paper, we develop closed-form expressions for the throughput achieved by the feedback schemes of LTE. The analysis quantifies the joint effects of three critical components on the overall system throughput-scheduler, multiple-antenna mode, and the feedback scheme-and brings out its dependence on system parameters such as the number of resource blocks per subband and the rate adaptation thresholds. The effect of the coarse subband-level frequency granularity of feedback is captured. The analysis provides an independent theoretical reference and a quick system parameter optimization tool to an LTE system designer and theoretically helps in understanding the behavior of OFDMA feedback reduction techniques when operated under practical system constraints.

Item Type:	Journal Article
Publication:	IEEE Transactions on Vehicular Technology
Publisher:	IEEE
Additional Information:	Copyright 2011 IEEE. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Channel quality feedback;Long-Term Evolution (LTE);multiple-antenna diversity;orthogonal frequency-division multiple access (OFDMA);rate adaptation;scheduling
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	23 Dec 2011 11:48
Last Modified:	23 Dec 2011 11:48
URI:	http://eprints.iisc.ac.in/id/eprint/42851

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