中文摘要：

本文研究了多载波码分多址两跳放大转发中继系统的能量效率与频谱效率关系,利用随机矩阵理论的渐近分析推导了系统分别采用协作式和分布式放大转发中继时,系统能量效率与频谱效率关系的显式表达式.分析了不同系统参数对能量效率的影响.此外,还分析了系统要使频谱效率最优和能量效率最优时使用系统资源的区别.最后,通过仿真验证了理论分析的有效性.结果表明,能量效率与负载因子和中继个数的关系不是单调的,存在一个使能量效率最优的负载因子和中继个数,此外,使能量效率最优的负载因子和中继个数总小于或等于使频谱效率最优的负载因子和中继个数.

英文摘要：

In this paper,we investigate the relationship between the energy efficiency （EE） and the spectral efficiency （SE） in multi-carrier code division access （MC-CDMA） two-hop amplify-and-forward relay systems.We resort to asymptotical analysis with the random matrix theory to derive the closed-form SE-EE relationship when the cooperative relays or distributed relays are considered.We analyze the impact of system parameters on the value of the EE and the SE-EE relationship.Moreover,we study the difference between the SE-and EE-oriented system in using the resources.Finally,we provide simulation results to validate our analytical results.Our studies show that the EE is not a monotonic function of the load factor and the number of relays,so that there is a value of the load factor and the number of relays that can maximize the EE.Moreover,the EE-oriented load factor and the number of relays are always less than or equal to the SE-oriented ones.