Multiuser scheduling for cognitive MIMO with channel estimation errors and feedback delay

Abstract

A multiuser scheduling multiple-input multipleoutput (MIMO) cognitive radio network (CRN) with space-time block coding (STBC) is considered in this paper, where one secondary base station (BS) communicates with one secondary user (SU) selected from K candidates. The joint impact of imperfect channel state information (CSI) in BS → SUs and BS → PU due to channel estimation errors and feedback delay on the outage performance is firstly investigated. We obtain the exact outage probability expressions for the considered network under the peak interference power IP at PU and maximum transmit power Pm at BS which cover perfect/imperfect CSI scenarios in BS → SUs and BS → PU. In addition, asymptotic expressions of outage probability in high SNR region are also derived from which we obtain several important insights into the system design. For example, only with perfect CSIs in BS → SUs , i.e., without channel estimation errors and feedback delay, the multiuser diversity can be exploited. Finally, simulation results confirm the correctness of our analysis.

Performance of scheduled space–time block coding scheme in cognitive multiple‐input–single‐output networks with imperfect channel state information

“…Then, at time slot t, the CDF of the channel power gain between BS and D k* , e.g. X*, can be expressed as [24,31] (see (27)) , where Pr[A k ] = 1/K, since we consider i.i.d. channel, and f X k τ | A k (y | A k ) represents the PDF of the estimated SNR associated to D k conditioned on event A k .…”

“…Since Y τ = ∥ G τ ∥ F 2 is a chi-square RV with a degree of freedom of 2N BS N PU , the PDF and CDF of Y τ are given as follows [24,32]:…”

“…On the basis of the definition of the OP [24], the OP in the considered system utilising the scheduled STBC scheme is given as P out (γ th ) = Pr(γ k* STBC ≤ γ th ) = F γ k* STBC(γ th ) .…”

Outage probability of scheduled MRT scheme in cognitive MISO networks with imperfect CSI

“…In [15], the authors proposed a transmit AS with receive generalised selection combining scheme in a cognitive MIMO relaying network. In [19–21], the performance of the scheduled STBC scheme was investigated.…”

Performance analysis of cognitive AF relay networks with multiuser switched diversity in Rayleigh fading channels

“…Opportunistic scheduling was used to select the secondary user with the best second hop SNR. Most recently, the opportunistic scheduling was used in [28] and [29] to select among secondary users in DF and AF multiple-input multiple-output cognitive relay networks, respectively.…”