SIMULATION ANALYSIS OF COMMUNICATION PROTOCOL FOR RAILWAY CONTROL SYSTEMS

초록

Most of signaling equipments are composed of vital relay-based system until few years ago. However, according to the advance of computer and communication technology, this signaling equipment is computerized. The link for interface between these signaling is also replaced by digital communication channel and the importance of this communication link is increased. That is the computerization of railway signaling equipment, the need of protocol for interface between these equipments is increasing. Meanwhile, there are some difficulties in the maintenance and repair of signaling communication equipments because they are offered from different manufactures and have different signaling interfaces or protocols with each other, although they do the same functions. To remove these difficulties and reduce corresponding costs, the standardization of the equipments is deeply needed. For both railway signaling reliability and standardization, various signaling operation characteristics and schemes - error detection and control methods, flow control methods, ARQ and data link control protocol and etc. - have to be analysis to be adapted to the railway signaling. In this research we have been developed a simulation environment and a simulator to analysis performance of railway signaling protocol. The main purpose of data link control simulation is to calculation the link utilization, BER and Frame Error Rate under various link conditions such as signal type and signaling rate, frame error rate, physical link conditions, and ARQs. Generic ARQ schemes used in data link control are Stop-and-Wait ARQ, Go-Back-N ARQ and Selective-Reject ARQ. From several calculation steps under link conditioning parameters, above mentioned some metrics for protocol of railway signaling can be obtained. The performance of data link control protocol for railway signaling is analyzed through designed simulation tool. And we designed the protocol for railway signaling from these simulated resulted. This designed protocol was adapted as the Standard by Korea National Railroad