基于OFDM的DF中继链路能效最优资源分配策略

针对DF模式的OFDM中继链路，将能效最大化资源分配问题转化为在用户最小速率需求和系统总发射功率受约束条的件下，子载波配对和功率分配的联合优化问题，提出一种低复杂度联合最优资源分配策略，并证明速率和功率约束条件下中继链路全局能效最优解的唯一性.仿真结果表明，与固定子载波配对策略相比，当中继节点位于源和目的节点连线中点位置，Rmin=1.5 Mbit/s时，排序子载波配对策略的链路可达速率和系统能效分别提高了2.3%和3.1%；与传统的等功率分配、速率最大化和功率最小化注水算法相比，本文方案能够在保证用户最小速率需求和系统功率约束的同时，自适应分配资源以实现系统能效最优. 

Scheme for Optimal Energy-Efficient and Resource Allocation in OFDM-Based DF Relay Link

The resource allocation problem in OFDM-based DF-Relayed link was formulated as a joint optimization of subcarrier pairing and power allocation while maximizing energy efficiency (EE) with both the minimum rate and the total transmission power constraints. It is proved that the optimal energy-efficient solution under the minimum rate and maximum transmit power constraints for the OFDM-based DF-Relayed link is globally unique. Subsequently, a resource allocation scheme with low complexity was proposed. Simulation results show that compared with the fixed subcarrier pairing strategy, the data rate and EE of the proposed scheme with the subcarriers pairing strategy are respectively increased by 2.3% and 3.1% when the relay node is located at the midpoint position between the source and destination nodes, and Rmin=1.5 Mbit/s. Compared with the traditional equal power allocation scheme, rate maximization and waterfilling power minimization schemes, the proposed scheme achieves the optimal EE while guaranteeing minimum rate requirements and maximum total transmission power constraints.