Robust Designs For MISO-Based Cognitive Radio Networks With Primary User's Partial Channel State Information

Cognitive radio is an emerging technology improving the spectrum utilization efficiency in communication systems. In this paper, we are interested in a multiple-input single-output (MISO) based cognitive radio (CR) network where the secondary user (SU) shares the same frequency band with the primary user (PU). It is assumed that the SU transmitter (SU-Tx) has perfect channel information (CSI) from SU-Tx to SU receiver (SU-Rx), but partial CSI from SU-Tx to PU receiver. We propose a robust design method to determine the optimal transmission covariance of SU-Tx to maximize the rate of the SU while keeping the interference power to the PU less than a threshold with high probability. This problem is formulated as a semi-infinite programming (SIP) problem. Two algorithms are proposed to transform this SIP problem into a finite constraint problem, and it is shown that these algorithms obtain the optimal solution. Simulations are presented to validate the effectiveness of the proposed algorithms.