认知无线电中频谱效率与能量效率的折中分析

Trade-off Analysis of Spectral Efficiency and Energy Efficiency in Cognitive Radio

在接收端较高的比特信噪比能够提高数据包检测率,但同时也消耗更多的能量,导致能量效率降低。为此,在认知无线电技术可灵活配置的基础上,研究频谱效率(SE)和能量效率(EE)的折中问题,提出综合指标频谱/能量效率(SEE)对SE和EE进行偏好分析的方案。对于不同的联合调制与编码方式,获取信号传输能量和每一帧信息比特长2个参数的闭式解,考虑不同情形的SE和EE,以更好地提高认知无线电的自适应性。仿真结果表明,该方案可实现SE和EE之间的均衡折中,比单纯优化其中任何指标达到的效果要更好。

Generally,with higher average energy per bit to noise power spectral density ratio at the receiver,the packet can be more successfully detected. However,this situation quires more energy,lowering Energy Efficiency（ EE）. Based on the configurability of Cognitive Radio（ CR）,this paper studies the trade-off between Spectral Efficiency（ SE） and EE from the angle of contacting with practical application more closely. It proposes a general metric Spectral/Energy Efficiency（ SEE） scheme to facilitate the analysis which quantifies the preference of SE or EE. Closed-form solutions for symbol transmission energy and the length of information bits per frame are obtained for various combined modulation and channel coding modes. The closed-form solutions further facilitate the adaptability of cognitive radio considering both SE and EE in various scenarios. Simulation results showthat the scheme is capable to perform balanced trade-off between SE and EE,it can obtain better performance than simply optimizing any of the two metrics.