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2008

Limited feedback schemes for downlink OFDMA based on sub-channel groups

8 years 10 months ago
Limited feedback schemes for downlink OFDMA based on sub-channel groups
Abstract--In a downlink Orthogonal Frequency Division Multiple Access (OFDMA) system, optimally allocating sub-channels across mobile users can require excessive feedback of channel state information (CSI). We consider an OFDMA model in which the feedback overhead is explicitly taken into account, given a fixed feedback rate and finite coherence time. The tradeoff between feedback rate and sum capacity is studied for two limited feedback schemes: a sequential scheme in which the users send compressed feedback bits over consecutive time slots, and a contention scheme in which users send their feedback via a random access protocol. For both schemes each feedback bit indicates a request for a group containing multiple subchannels. We show that the sum capacity for both schemes with optimized sub-channel groups grows linearly with the number of sub-channels N, and that the associated constant increases as the log of the normalized feedback rate measured in bits per coherence time per sub-c...
Jieying Chen, Randall A. Berry, Michael L. Honig
Added 13 Dec 2010
Updated 13 Dec 2010
Type Journal
Year 2008
Where JSAC
Authors Jieying Chen, Randall A. Berry, Michael L. Honig
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