Power Allocation in Decode-and-ForwardCooperative OFDM Systems Using Perfect andLimited Feedback
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Graphical Abstract
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Abstract
To maximize the spectral e±ciency of
a Decode-and-forward (DF) cooperative Orthogonal fre-
quency division multiplexing (OFDM) system, we ¯rst pro-
pose the optimal power allocation algorithm when per-
fect Channel state information (CSI) feedback is available.
Since perfect CSI feedback is unrealistic, we further pro-
pose a power allocation scheme using limited feedback,
where the power allocation vectors for the source and re-
lay are limited in two ¯nite power allocation tables respec-
tively. In this scheme, the destination chooses the power
allocation vectors for the source and relay, and feeds the
indices of the vectors back. The power allocation tables
are designed by using the Lloyd algorithm. Simulation re-
sults show that the perfect CSI feedback power allocation
scheme achieves the best performance, and that the per-
formance of the limited feedback scheme lies between the
perfect CSI scheme and the scheme with no CSI.
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