Optimal Pilot Placement in Cognitive Radio Systems for Wiener Filtered MMSE Channel Estimation

Non-Contiguous Orthogonal Frequency Division Multiplexing (NC-OFDM) Cognitive Radios (CRs) pose an intriguing situation for optimal pilot-pattern generation. It has been proposed that in order to attain the lowest possible Mean Squared Error (MSE) of a channel estimator, the pilots should be placed adjacent to an interfering Primary User (PU) to allow for the highest pilot to data symbol cross-correlation and the lowest pilot auto-correlation. In past research, this has been shown to provide a significant decrease in the channel estimator's MSE; moreover the optimal power loading required such that the PU does not experience interference above a certain threshold from the Secondary User (SU) is not taken into account.

Provided by: IARIA Topic: Mobility Date Added: Jul 2011 Format: PDF

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