On MIMO Cognitive Radios with Antenna Selection

Abstract

Abstract-With the ever increasing interest in multiple-input multiple-output (MIMO) cognitive radio (CR) systems, reducing the costs associated with RF-chains at the radio front end becomes a very important factor. In this paper, we propose two solutions to the problem of joint transmit-receive antenna selection with the objective of maximizing data rates and satisfying interference constraints at the primary user (PU) receiver. In the first method we approximate the original non-convex optimization problem with an iterative way of solving a series of smaller convex problems. Then we present a novel, norm-based transmit receive antenna selection technique that simultaneously improves throughput while maintaining the PU interference constraints. We show that this simple approach yields near optimal results with massive complexity reductions. In addition to making a performance comparison between the proposed approaches and the optimal exhaustive search approach, we establish that antenna selection is a promising option for future MIMO CR devices.

Proactive Spectrum Sharing for SWIPT in MIMO Cognitive Radio Systems Using Antenna Switching Technique

“…-But, if P p goes to infinity, the interference induced by PT at SR is very high and P S ,out goes to one. Also, as P p goes to infinity, Q(K) goes also to infinity and, hence, according to (15), K goes to N p − 1 and the asymptotic results of Q, PO, and P P,out are the same as the ones discussed above when E t goes to zero. Applying the limit when P p goes to infinity to (59), (60), and (61), we get that Q, PO, and P P,out converge to infinity, zero, and zero, respectively.…”

“…When the secondary receiver (SR) has multiple antennas, the maximum ratio combining (MRC) technique was investigated for CR networks in [13], [14]. In [15], a joint transmit-receive antenna selection in MIMO CR network was proposed to maximize the CR data rates satisfying interference constraints at primary receivers (PRs) by using two approaches: one based on iterative approach and one normbased selection approach. Near-optimality of the norm-based approach was shown compared to the exhaustive search.…”

Optimal Transmit Strategy for MISO Channels With Joint Sum and Per-Antenna Power Constraints

“…Combinations of several power constraints have been considered in a range of other scenarios, for instance in the context cognitive radio channels [16], [17] or wiretap channels [18]. These works build on known results considering sum power, individual power or per-antenna power constraints, and extend them with additional power constraints to limit the received power at a third node.…”

“…In particular for the cognitive radio channel, Zhang et al studied in [16] the weighted rate sum maximization problem in which the secondary users have not only the sum power constraint but also interference constraints. The sum power constraint and interference constraints are also considered in [17], where the authors used the idea of antenna selection to jointly satisfy interference constraints at primary users while improving the rates of secondary users. In addition, the optimization problem with joint power and interference constraints has also received much attention in green radio setups [19]- [21].…”

Performance analysis of transmit antenna selection for cognitive radio systems with imperfect channel estimation

“…However, the benefits come at the increased hardware cost with multiple radio frequency (RF) chains. To reduce the hardware cost, the antenna selection technique has triggered significant interest for CR systems recently [4,5]. With negligible hardware cost, the antenna selection based CR system can obtain the most advantages of multiple antennas and the interference caused to PU can also be well-controlled.…”