电力线与无线双媒质协作的自适应双向中继通信关键技术研究

With the development of Smart Grid, it is necessary to establish a reliable, efficient, bi-direction, and collaborative communication network. Both power line communication (PLC) and wireless communication can be widely applied to Smart Grid. The cooperation of PLC and wireless communication provides a complementary advantage to each other and saves construction cost. In order to solve the key problem of energy efficiency and bi-direction relaying scheme deficiency in hybrid cooperation, the project studies the adaptive bi-direction relaying technology based on amplify-and-forward and decode-and-forward protocol for PLC and wireless communication cooperation, using a coding scheme with both LDPC and Physical layer network coding(PLNC). According to the random fading index of power line in Smart Grid which is hard to measure in time, a lognormal distribution fading of power line is adopted in the research. Under the condition of asymmetric and hybrid fading and impulsive noise, the analysis framework and improved EXIT method for analyze the system performance would be proposed to investigate the influencing mechanism between the system performance and factors including the asymmetric channel, resource and PLNC scheme. Based on the proposed optimal resource allocation and jointly PLNC scheme with more balanced performance, an adaptive bi-direction relaying scheme with appropriate energy efficiency and reliability would be proposed to strike a balance between complexity and performance, where the methods of comprehensive performance evaluation and mathematical modeling are considered. The project content satisfies the developing requirement of multiple communication cooperation and bi-direction communication in Smart Grid, providing a necessary theoretical basis for the study of multiple media cooperation communication.

智能电网发展需要建立可靠高效、双向互动与融合协同的通信系统。无线与电力线通信在其中具有广泛应用前景，二者有机协作可以优势互补、提高资源利用率。已有混合协作存在能效与灵活性差、双向中继机制不足等问题，因此课题基于放大前传和译码前传中继协议，联合LDPC码和物理层网络编码(PLNC)，研究电力线和无线双媒质协作的自适应双向中继关键技术：采用基于对数正态分布衰落与脉冲噪声的电力线信道模型，研究电力线与无线混合衰落和脉冲噪声条件下的系统性能分析框架和改进的EXIT分析理论；并探讨非对称双媒质信道、功率等资源和PLNC算法制约系统性能的机理，提出系统资源优化分配方案与性能更加均衡的联合PLNC算法；最后利用综合性能评估、联合协议设计与数学建模等方法，提出复杂度和性能折衷、能效和可靠性适度的自适应双向中继方案。此研究满足智能电网多通信协作和双向通信发展要求，将丰富双媒质协作的研究内容，提供新颖的视角。

针对混合衰落和脉冲噪声影响的双媒质两跳中继系统，建立了系统采用放大前传（AF）和译码转发（DF）等经典中继协议时的理论性能分析框架，得到双媒质信道衰落和功率等资源制约中继系统误码率和中断概率等性能的机理，提出了基于黄金分割等数值计算的功率优化分配算法。为了解决传统EXIT算法仅适用于高斯信道或是满足方差为均值二倍信道的问题，项目提出了基于最大期望估计和多维高斯模型的多维外部信息转移（EXIT）性能分析理论，分析了非对称信道衰落和脉冲噪声影响双媒质系统迭代译码性能的机理，提出了兼顾噪声门限和译码误码率的LDPC度分布联合优化算法。针对基于LDPC码置信传播（BP）迭代译码的双媒质协作中继系统，考虑脉冲噪声的门限效应，提出了双向中继通信中电力线多维脉冲噪声近似处理和物理层网络编码算法，提出了一种基于信噪比门限值的自适应中继转发算法。针对异构混合通信系统，提出了基于综合性能评估的网络接入选择、高能效用户接入选择和双媒质接入MAC等算法，以改善包括能效、可靠性和鲁棒性等在内的系统综合性能。相关理论和算法的提出，为构建接入灵活、结构合理、复杂度与性能折衷的高能效通信网提供了新颖研究视角和必要基础支撑。