On the Optimum Energy Efficiency for Flat-Fading Channels with Rate-dependent Circuit Power
On the Optimum Energy Efficiency for Flat-Fading Channels with Rate-dependent Circuit Power
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DOI：
10.1109/tcomm.2013.111013.130150
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发表时间：
2013-10
影响因子：
8.3
通讯作者：
Tao Wang;L. Vandendorpe
中科院分区：
文献类型：
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作者：
Tao Wang;L. Vandendorpe
本文研究了平坦衰落信道上通信链路的最优能量效率(EE)和相应的频谱效率(SE)。通过每个消息比特传输的总能量消耗来评估EE。考虑了三种信道情况，即具有发射机可用信道状态信息的静态信道(CSIT)、具有发射机可用信道分布信息的快速变化(FV)信道(CDIT)和具有CSIT的FV信道。链路的电路功率被建模为ρ+κφ(R)瓦特，其中ρ>；0和κ≥0是两个常量，φ(R)是传输速率R≥0的一般递增和凸函数。对于所有三种信道情况，研究了EE和SE之间的权衡。结果表明，当SE从0增加到最优SE时，EE严格提高；当SE增加到超过最佳SE时，EE严格退化。研究了κ，ρ和其他系统参数对最优EE和相应SE的影响，以获得洞察力。对于所有信道情况，一些重要而有趣的结果包括：(1)当κ增加时，当φ(R)=R时，对应于最优EE的SE应该保持不变，但如果φ(R)是R的严格凸的，则对应于最优EE的SE应该减小；(2)当与速率无关的电路功率ρ增加时，对应于最优EE的SE必须增加。利用二分法给出了求解最优SE的多项式复杂度算法。仿真结果证实了这一观点，并对三种情况下的最优效率进行了比较。
This paper investigates the optimum energy efficiency (EE) and the corresponding spectral efficiency (SE) for a communication link operating over a flat-fading channel. The EE is evaluated by the total energy consumption for transmitting per message bit. Three channel cases are considered, namely static channel with channel state information available at transmitter (CSIT), fast-varying (FV) channel with channel distribution information available at transmitter (CDIT), and FV channel with CSIT. The link's circuit power is modeled as ρ+κφ(R) Watt, where ρ>0 and κ≥0 are two constants and φ(R) is a general increasing and convex function of the transmission rate R≥0. For all the three channel cases, the tradeoff between the EE and SE is studied. It is shown that the EE improves strictly as the SE increases from 0 to the optimum SE, and then strictly degrades as the SE increases beyond the optimum SE. The impact of κ, ρ and other system parameters on the optimum EE and corresponding SE is investigated to obtain insight. Some of the important and interesting results for all the channel cases include: (1) when κ increases the SE corresponding to the optimum EE should keep unchanged if φ(R)=R, but reduced if φ(R) is strictly convex of R; (2) when the rate-independent circuit power ρ increases, the SE corresponding to the optimum EE has to be increased. A polynomial-complexity algorithm is developed with the bisection method to find the optimum SE. The insight is corroborated and the optimum EE for the three cases are compared by simulation results.