Miśkowicz Marek
AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków, Poland.
Sensors (Basel). 2007 Dec 21;7(12):3535-3559. doi: 10.3390/s7123535.
The paper addresses the problem of the mean access delay characteristics in termof the channel load for networked sensor/control systems in LonWorks/EIA-709 technology.The system modelling is focused on the Media Access Control protocol that provides theload prediction and determines the key network characteristics. The network model assumesthe consistency of load prediction between the nodes, and that the Transaction ControlSublayer does not introduce limitations on the data transmission. The latter means that thenumbers of concurrent outgoing transactions being in progress are unlimited. Furthermore, itis assumed that the destination addresses of transmitted messages are distributed rather thanconcentrated on particular nodes. The analytical approach based on Markov chains isapplied. The calculation of transition probabilities of the Markov chain is exemplified by theload scenario where all the transactions are acknowledged, unicast, and the optionalcollision detection is enabled. On the basis of the stochastic analysis, the probabilities of asuccessful transmission and collision, respectively, are computed. Furthermore, thenumerical results of the mean access delay are reported. The simulative validation ofanalytical results is provided.
本文探讨了基于LonWorks/EIA - 709技术的网络传感器/控制系统中，通道负载条件下的平均访问延迟特性问题。系统建模聚焦于提供负载预测并确定关键网络特性的媒体访问控制协议。网络模型假定节点间负载预测的一致性，且事务控制子层不会对数据传输造成限制。后者意味着正在进行的并发传出事务数量不受限制。此外，假定传输消息的目的地址是分散的，而非集中在特定节点上。应用了基于马尔可夫链的分析方法。以所有事务均得到确认、采用单播且启用可选冲突检测的负载场景为例，说明了马尔可夫链转移概率的计算过程。基于随机分析，分别计算了成功传输和冲突的概率。此外，还报告了平均访问延迟的数值结果。对分析结果进行了仿真验证。
