SINR balancing approach for network beamforming in cognitive two-way relay networks

Abstract

In this paper, we consider the problem of distributed network beamforming for a bidirectional cognitive relay network which consists of two secondary transceivers and K cognitive relay nodes and a primary network with a transmitter and receiver, over the same spectrum. For effective use of spectrum, we propose a two-step two-way relaying scheme for cognitive networks. Our aim is to design the beamforming coefficients to maximize quality of service (QoS) for the secondary network while satisfying tolerable interference constraint for the primary network. We show that this approach yields a closedform solution. Our simulation results show that the maximum achievable SINR improved while the tolerable interference on primary receiver increased.

Distributed beamforming for SINR balancing approach in cognitive two-way relay networks with imperfect channel state information

“…2 illustrates the average values of the maximum achievable SINRs versus the maximum interference power that primary receiver can tolerate for different values of a p . We have also plot the results when we assumed that we have full CSI for comparison [18]. This figure shows that the uncertainty about the channel coefficients can be degrade the performance of the network considerably.…”

Joint Distributed Beamforming and Power Allocation in Underlay Cognitive Two-Way Relay Links Using Second-Order Channel Statistics

“…Thus, distributed beamforming improves outage probability and data rates and is implemented, subject to interference constraints, to maximize the signal-to-interference-and-noise-ratio (SINR), which also must be balanced between the two secondary terminals, giving higher power efficiency [11]. To achieve these goals, we optimally allocate the signal powers of and and adjust antenna gains (i.e., beamforming) to balance and maximize SINR.…”

“…Moreover, the availability of perfect CSI is also assumed. For example, with AF relaying, beamforming and power allocation for overlay [20]- [24] and underlay [11], [25]- [29] cognitive relay systems have been developed. References [25] and [26] studied one-way multi-antenna relays.…”

“…And [27] investigated one-way single-antenna relays. In [11], [28], [29], beamforming coefficients were derived for two-way relays.…”