©2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

The statistical side information of interference channels is exploited in this paper to derive a novel uncoordinated on-line pilot design strategy for opportunistic communications. Assuming a time division duplex (TDD), or frequency division duplex (FDD) with feedback, wireless network and reciprocity, we prove that the space-frequency pilot design technique in terms of minimum cross-interference to external-network users reduces to a classical minimum-norm problem. The advantages of this novel methodology are time-domain invariance to noise-subspace rotations, a maximally flat angle-frequency response, and robustness in front of frequency calibration errors. Simulation results are reported to assess the performance of the proposed strategy and the advantages of its low-resolution quantization in low signal-to- noise ratio (low-SNR) regimes.

Peer Reviewed