Energy-Efficient Power Allocation for Decode-and-Forward OFDM Relay Links

Abstract

Abstract. This paper investigates the power allocation aiming to optimize the energy efficiency for an OFDM two-hop relay link based on DF protocol. First, an equivalent single-hop link is used to replace the two-hop link, and the model of the energy efficiency is established. When modeling the energy efficiency of the link, the circuit power consumption is not only taken into account, but also modeled as a linear increasing function of the rate. Subsequently, the energy efficiency optimization problem is solved by convex optimization, and the optimal power allocation is obtained under rate constraint. After that, the energy efficiency performance is also analyzed. Finally, the correctness of the theoretical analysis is verified by simulation results which adopt the spatial channel model conforming to the 3GPP standard, and the influence of circuit parameters on the performance of the system is also studied. IntroductionDue to the sharp increase of the carbon emission and operating cost of wireless communication systems, energy efficiency(EE) has become a new design goal [1] .For a communication system, its EE can be evaluated by either the total energy consumption for transmitting per message bit(TEPB),or the number of message bits transmitted with per-Joule total energy consumption(NBPE). A higher EE is represented by either a smaller TEPB or a greater NBPE.Relaying was expected as an energy saving strategy by breaking a long distance transmission into several short distance transmissions. Cooperative relay transmission can expand the coverage of the network, improve the throughput and enhance the reliability of communication link. With the combination of relay and OFDM technology, optimal performance can be achieved via a reasonable allocation of subcarriers and power. In [2],under the premise of the optimal subcarrier pairing and the total rate constraint, the resource allocation algorithm is designed for the selective decode-and-forward(DF) relay OFDM link, which makes the total power consumption minimum. However, most of current studies don't take the circuit power consumption into account.

Energy Efficiency Maximized Resource Allocation for Opportunistic Relay‐Aided OFDMA Downlink with Subcarrier Pairing

“…It is interesting to further study how to improve EE of relay-aided OFDMA networks. When users lie outside the BS's radio coverage, EE maximized RA problems for OFDMA networks using subcarrier-pair-based DF protocols have been addressed in [25][26][27][28][29]. In these works, every subcarrier in the first time slot is paired with a subcarrier in the second time slot for the relay-aided transmission.…”