Difference Antenna Selection and Power Allocation for Wireless Cognitive Systems

IEEE Transactions on Communications (Impact Factor: 1.98). 10/2010; DOI: 10.1109/TCOMM.2011.091911.100633
Source: arXiv

ABSTRACT In this paper, we propose an antenna selection method in a wireless cognitive radio (CR) system, namely difference selection, whereby a single transmit antenna is selected at the secondary transmitter out of $M$ possible antennas such that the weighted difference between the channel gains of the data link and the interference link is maximized. We analyze mutual information and outage probability of the secondary transmission in a CR system with difference antenna selection, and propose a method of optimizing these performance metrics of the secondary data link subject to practical constraints on the peak secondary transmit power and the average interference power as seen by the primary receiver. The optimization is performed over two parameters: the peak secondary transmit power and the difference selection weight $\delta\in [0, 1]$. We show that, difference selection using the optimized parameters determined by the proposed method can be, in many cases of interest, superior to a so called ratio selection method disclosed in the literature, although ratio selection has been shown to be optimal, when impractically, the secondary transmission power constraint is not applied. We address the effects that the constraints have on mutual information and outage probability, and discuss the practical implications of the results. Comment: 29 pages, 9 figures, to be submitted to IEEE Transactions on Communications

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we consider a cognitive multiple access channel (MAC) in which the secondary users seek to communicate with the secondary base station in a spectrum-sharing environment. The base station selects only one secondary user, which maximizes the weighted difference between the channel power gains of the interference link and the cognitive transmission link. This selection strategy can also be specialized to selecting the secondary user that has either the least interference channel gain or the highest data channel gain. Consequently, the selected secondary user is subject to an interference power constraint in order to avoid harmful interference inflicted on the primary user. It is assumed that the primary user and secondary users operate under statistical quality of service (QoS) constraints imposed as limitations on the buffer size. In this setting, we characterize the effective capacity for both primary user and the secondary users under different selection methods. The impacts of the secondary user selection method, the number of secondary users, QoS constraints on the performance of both the primary user and secondary users are investigated. We interestingly show that for a large number of secondary users, the performance of the primary user is not affected by the selection method in the interference-limited regime.
    GLOBECOM 2013 - 2013 IEEE Global Communications Conference; 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we consider a spectrum sharing cognitive radio system with ratio selection using a mean value-based power allocation strategy. We first provide the exact statistics in terms of probability density function and cumulative density function of the secondary channel gain as well as of the interference channel gain. These statistics are then used to derive exact closed form expression of the secondary outage probability. Furthermore, asymptotical analysis is derived and generalized diversity gain is deduced. We validate our analysis with simulation results in a Rayleigh fading environment.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: For multiple-input multiple-output cognitive radio systems, we propose an optimal single transmit and receive antenna selection scheme which maximizes the signal-tointerference-and-noise ratio. Considering peak interference power constraint, peak transmit power constraint, and interference from primary transmitter to cognitive receiver, we theoretically derive the exact system outage probability. It is shown that the theoretical results match simulation results.
    Wireless Personal Communications 11/2014; 79(2):1435-1443. DOI:10.1007/s11277-014-1938-1 · 0.98 Impact Factor

Full-text (2 Sources)

Available from
Jun 4, 2014