Power Allocation and Outage Probability Analysis of AF Relaying Systems With Multiple Antennas at Terminal Nodes

• Published in: IEEE transactions on vehicular technology Vol. 66; no. 1; pp. 377 - 384
• Main Authors: Poursajadi, Sajad, Madani, Mohammad Hossein, Bizaki, Hossein Khaleghi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplify-and-forward (AF) relaying; Antennas; Closed-form solutions; Fading channels; Mathematical analysis; MIMO; multiple-input multiple-output (MIMO); Nodes; Optimization; outage probability; Performance enhancement; power allocation; Power management; Relay; relay selection; Relaying; Relays; Resource management; Signal to noise ratio; Systems design
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2016.2542852

In this paper, the performance of a nonregenerative relaying network of multiple-antenna terminal nodes is analyzed with respect to the power allocation issue. Assuming that complete channel state information (CSI) of all links is known at the destination terminal, an optimal power allocation (OPA) approach is investigated subject to constant total power with the objective of maximizing the instantaneous signal-to-noise ratio (SNR) at the destination. Generally, by this OPA approach, the total available power in the system is appropriated to source and relay nodes proportional to channel properties with the aim of coordinating the source-relay and relay-destination hop quality. Closed-form expressions for the outage probability are analytically derived, considering both conventional and maximized SNRs. It is shown that OPA outperforms the conventional uniform power allocation, although the achieved improvement is more significant if the number of destination antennas is less than the number of source antennas. Moreover, the results indicate that the effect of OPA on the performance improvement is significant if the relay node is close to the source terminal. Moreover, it is seen that the minimum number of the source and destination antennas is a determinant parameter in the evaluation of the outage probability. Hence, it is demonstrated that for an efficient system design, the number of source antennas should be as close as possible to that of the destination antennas. In addition, the relay selection scheme is considered to further improve the performance of the system. Finally, simulation results are presented, which confirms the validity of the analysis.