Energy‐efficient adaptive power allocation in orthogonal frequency division multiplexing‐based amplify‐and‐forward relay link

Abstract

Recently, improving energy efficiency has been a new tendency in wireless relay communication. However, the introduction of relay technology may increase the system capacity, but is often followed by a more severe energy-efficiency problem when compared with traditional single-hop system. In this study, based on orthogonal frequency division multiplexing-based frequency-selective channel of amplify-and-forward relay link, a suboptimal two-step power allocation algorithm of subcarriers is proposed to maximise the energy efficiency. The proposal includes two steps. First, a suboptimal subcarrier matching is achieved for introducing a virtual direct link, which may reduce the dimensionality of the power allocation. Second, the allocation problem of relay network is simplified as that in traditional cellular network. Thus, the optimal power allocation of virtual direct link can be obtained by one-dimensional search method. Furthermore, the effects of rate and power constraints on the energy-efficiency problem are analysed. Simulation shows that the suboptimal solution of the proposed algorithm is very close to the optimal solution, and the proposed energy efficient power allocation method can achieve the highest energy efficiency, compared with the rate adaptive and margin adaptive optimisations.

Fairness-Aware Energy-Efficient Resource Allocation for AF Co-Operative OFDMA Networks

“…Recently, a flourish of works has been done for maximizing the EE of cooperative OFDMA systems [13]- [18]. More specifically, Chen et al [13] proposed a suboptimal algorithm to maximize the EE of AF orthogonal frequency division multiplexing (OFDM)-based system.…”

“…More specifically, Chen et al [13] proposed a suboptimal algorithm to maximize the EE of AF orthogonal frequency division multiplexing (OFDM)-based system. The proposed algorithm considered a simplified scenario of a single source node communicating with a single destination node through a single relay.…”

“…is the SNR of the direct link between MS k and the BS on subcarrier n with γ (SD) k,n = 1 It was shown in [13], [18] that subcarrier pairing, i.e., using different subcarriers on the links between MS-RS and RS-BS, provides marginal improvements in performance at the expense of huge computational complexity.…”

Energy‐efficient transmission for decode‐and‐forward dual‐hop networks with asymmetric traffic demands

“…For instance, an energy efficient power allocation algorithm is developed in [26] for the DF relaying systems, which improves the energy efficiency remarkably. A suboptimal power allocation scheme is presented in [27] for the AF relaying system. Optimal relay location is studied in [28] for better energy efficiency performance in one-way relaying systems.…”

“…Equation (27) is in the form of quadratic constrained quadratic programs, which can be efficiently solved by the SDR method [31]. We denote the corresponding solution as w 1 and the resulting relay power as p r,1 .…”