机载PLC信道传递函数建模与概率保证分析

Airborne PLC channel modeling by transfer function and its probabilistic guarantee analysis

采用电源线通信(PLC)技术替代部分机载电子设备之间的数据电缆可以简化布线并实现减重。根据机载电源线环境及航空电子通信要求,需要解决信道衰落及噪声干扰条件下PLC实时性能评价问题。针对机载电源线的布线拓扑结构,采用“自底向上”构造电压比方程的形式给出了PLC信道传递函数的建模方法;推导得出信道传递函数、信道增益和瞬时信道容量之间的关系;在有效容量理论框架下,通过论证积压队列的非空概率与服务质量(QoS)指数的关系,使得能够从瞬时信道容量简便地求得延迟违规概率,用以评价实时性能的概率保证。通过仿真验证了延迟违规概率算法的准确性,并得到不同信道传递函数条件下延迟界限与违规概率的关系,说明了信道衰落显著地影响延迟约束下机载PLC系统的概率保证实时通信速率。

Wiring can be made simpler and lighter by using power line communication(PLC)technology to replace some of the data cables used to connect avionics systems.According to airborne power line environment and avionics communication requirements,it is necessary to solve the problem of evaluating the real-time performance of PLC under the conditions of channel fading and interference.First of all,according to the wiring topology of the power lines in a certain aircraft,a modeling method of the PLC channel by transfer function is achieved in the form of a"bottom-up"construction with voltage ratio equations.Subsequently,the relationship between the transfer function,channel gain and instantaneous Shannon capacity is deduced.According to the effective capacity theory,by exploiting the relationship between the non-empty probability of the backlog queue and the quality of service(QoS)factor,It is possible to easily obtain the delay violation probability from the instantaneous Shannon capacity to evaluate the probabilistic guaranteeing of real-time performance.Simulation results verify the accuracy of our models and analysis to estimate the delay violation probabilities,and show the relationship between the delay limit and the violation probability under different channel transfer functions.They also demonstrate how the channel fading significantly affects the sustained real-time rate for airborne PLC systems under the probabilistic guaranteeing delay constraint.