Performance Analysis for RUB-Based Cognitive Radio Network with Cooperative Beam Selection

This paper studies the performance of a RUB-based cognitive radio (CR) network, which coexists with a primary network with single primary transmitter (PT) and single primary user (PU). It is assumed that the PU can control the availability of each beam of the secondary base station (SBS) over a feedback link. The PU only needs to feed back to the SBS the index of the usable beams, which lead to the received SINR at the PU larger than a predefined beam selection threshold, and the outage probability of the primary system can be limited to a tolerable level. The SBS then selects one from the usable beams to achieve the largest throughput of the secondary system. We derive the accurate upper bound of the outage probability of the primary system and the exact throughput of the secondary system. Numerical examples show that to avoid the burst increase of the outage probability of the primary system, as well as achieve the maximal throughput of the secondary system, the beam selection threshold should be equal to the outage threshold of the primary system.