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.

Optimal power allocation for multiple input single output cognitive radios with antenna selection strategies

“…However, the hardware complexity and high cost are the main drawbacks of multiple antenna techniques because of the requirement for radio frequency chains. Antenna selection (AS) techniques have been extensively studied to overcome that shortage [11][12][13][14][15]. In [11], several AS strategies, namely, minimum interference strategy, maximum data channel gain strategy, maximum sum capacity strategy and the maximum signal-to-leak interference power ratio strategy are proposed for the multiple input single output (MISO) cognitive radio system, where the spectrum sharing model is used.…”

“…However, the difference selection requires to set a parameter, which is difficult to obtain in practice. To maximise CR data rates and satisfy interference constraints on the SU, two solutions to the problem of joint transmit-receive AS in MIMO CR are presented [13]. In [14], authors develop a novel optimal AS based on Chernoff-bound to minimise an upper bound on the symbol error probability at the SU receiver.…”

Performance analysis comparison of transmit antenna selection with maximal ratio combining and orthogonal space time block codes in equicorrelated Rayleigh fading multiple input multiple output channels

“…Performance analysis of MIMO systems employing OSTBC in correlated channel fading conditions has been done in [7]. Recently, there has been a growing interest to study performance analysis of these MIMO schemes for cognitive radios [8][9][10][11]. For MIMO-based cognitive radio systems, the popular antenna selection scheme discussed in [1] is no longer optimal in terms of minimum achievable BER for the secondary users.…”

“…For MIMO-based cognitive radio systems, the popular antenna selection scheme discussed in [1] is no longer optimal in terms of minimum achievable BER for the secondary users. Recent works including [8][9][10] propose several different ways to optimally or sub-optimally select secondary user antenna.…”

“…A summary of several antenna selection schemes has been done in [12]. It is important to note that uncorrelated channel fading conditions have been assumed in all these works except in [9]. The utility of the formulae we derive in this work is demonstrated by taking an example of a MIMO-based cognitive radio system.…”