Impact of the CSI on the Performance of Cognitive Relay Networks With Partial Relay Selection

Abstract

In a cognitive relay network, a secondary cooperative transmission, sharing the same spectrum band with N primary transmissions, is considered. Assuming imperfect channel state knowledge of the interference channels (from secondary transmitters to primary receivers) at the secondary nodes, we investigate the problem of secondary achievable rate maximization under a constraint on the interference caused at the primary receivers. Different scenarios are defined based on the accuracy of estimating the interference channels at the primary receivers and the number of feedback quantization bits. For each scenario, we derive expressions for both the secondary achievable rate and the primary interference probability. Then, we investigate the associated power allocation problem and provide a sub-optimal solution. Finally, analytical and simulation results illustrate the efficiency of the provided solution in terms of secondary achievable rate and primary interference probability.Index Terms-Cognitive Radio, Amplify-and-Forward, partial relay selection, quantization.

Energy-Efficient Path Selection Using SNR Correlation for Wireless Multi-Hop Cooperative Communications

“…Even for l k =1 and S k = {1}, the analogous outage performance to global CSI is achieved for high C p . In Figures 2a and 3a, the analytic results of the SNR correlation coefficient and the outage probability, obtained by (13) and (19), respectively, perfectly match the corresponding simulation results. In Figures 2b and 3b, the analytic results of the SNR correlation coefficient and the outage probability, obtained by (5) and (18), respectively, also well match their simulation results.…”

“…To enhance the limited end-to-end performance of the PPS, an efficient PPS scheme has been presented in [17], where only CSI for the hop with the smallest average channel power in each dual-hop path is used for the PPS. In addition, the end-to-end performances of the PPS have been widely studied for a decode-and-forward (DF) relaying system with an eavesdropper [18], a cognitive amplify-and-forward (AF) relaying system [19], and a non-orthogonal multiple access (NOMA)-based AF relaying system [20] in terms of the outage probability and ergodic capacity. Moreover, the PPS can be applicable to a cooperative NOMA system [21] and a relay-assisted multicast system [22] when those systems require limited CSI feedback.…”

Efficient signal detection for cognitive radio relay networks under imperfect channel estimation

“…The impact of imperfect estimation of the interference links was analysed in , where it was shown that for the case of imperfect channel state information (CSI), SUs' transmission may cause harmful interference to the PU. In , the performance of conventional channel estimation methods in correlated CR channels under imperfect channel sensing was studied, and achievable rates for reliable communication under both channel and sensing uncertainties were investigated. Assuming a cognitive multi‐hop decode‐and‐forward network, the effect of imperfect channel estimation on the PU receiver was analysed in .…”

Individual channel estimation for amplify‐and‐forward relay networks using in‐band superimposed training

“…The transmissions with the aid of relay nodes have received a lot of attention due to their potential exploitation of both time and spatial diversity by sharing the resources of different nodes in wireless networks [1][2][3]. To fully exploit the benefits of relay-aided networks, accurate channel knowledge of different links is required for coherent reception and optimal design [4][5][6][7]. However, channel state information (CSI) for different links is unavailable in practical relay networks, and thus, needs to be estimated.…”