Cooperative Feedback for Multi-Antenna Cognitive Radio Networks

Cognitive Beamforming (CB) is a multi-antenna technique for efficient spectrum sharing between Primary Users (PUs) and Secondary Users (SUs) in a cognitive radio network. Specifically, a multi-antenna SU transmitter applies CB to suppress the interference to the PU receivers as well as enhance the corresponding SU-link performance. In this paper, for a Multiple-Input-Single-Output (MISO) SU channel coexisting with a Single-Input-Single-Output (SISO) PU channel, the authors propose a new and practical paradigm for designing CB based on the finite-rate cooperative feedback from the PU receiver to the SU transmitter.