Performance of Massive MIMO Cognitive Radio Networks With Pilot Sharing Under SINR Requirements of Primary Users

摘要

In this paper, we investigate the power allocation problem in massive MIMO cognitive radio (mMIMO-CR) networks. In particular, we propose an orthogonal pilot sharing scheme at pilot transmission phase, where secondary users (SUs) are allowed to use pilots for channel estimation only when there are temporarily unused orthogonal pilots managed by the primary network (PN). Following this, we formulate the power allocation optimization problem of the secondary network (SN) to maximize the downlink sum rate of the SN subject to the total transmit power and primary users' (PUs') signal-interference-plus-noise-ratio (SINR) constraints. Next, we transform the original (nonconvex) problem into a convex one by using convex approximation techniques and propose an iterative algorithm to obtain the solution. Finally, the numerical results clarify that our proposed algorithm works effectively to achieve higher downlink sum rate of the SN under constraints of PUs, SINR in comparison with the constraints of PUs' peak interference power.