The Design And Implementation Of The Gateway Of An SMS-based Remote Monitoring System

SMS-based (Short Message Service-based) Remote Monitoring Systems are getting increasingly prevalent in the field of monitoring and control. Such monitoring systems, which incorporate the beauty of the GSM network, feature in short development period, low development cost, and efficient monitoring process in which SMS alarms are sent to related staff's handsets immediately and accurately.This paper elaborates on the design and development of the gateway program of an SMS-based monitoring system. The main function of a system gateway program is to compose and decompose the different types of PDUs defined the Short Message Transfer Protocol of SMS, to ensure the reliability of the transference of the short messages as well as the correctness of their contents, and to provide sending and receiving interfaces to the upper layer of a monitoring system. As an essential part of the system gateway, gateway program plays a significant role in the development of a SMS-based monitoring system. The quality of design of a gateway program is directly related to the stability, reliability and robustness of the entire monitoring system.This paper looks into the treatment scheme of a short message performed by SMS during the process of a peer-to-peer transference of the message. It also anatomizes the protocol and interfaces of SMS in the Short Message Transfer Layer. Based on the analysis, the paper provides the implementation of the gateway function.Since the implementation of some functions of the gateway system relies on proper customization of the format of short message user data, this paper gives some discussion on the key points of shaping a short message user data protocol.This paper brings forward a scheme of combine-using Message Reference and SMS-STATUS-REPORT defined in SM-TL as to make it possible for the originated mobile station to track the transference status of a submitted short message. This provides a solution for judging whether a short message has reached the terminated MS from the originated MS in the Short Message Application Layer, and has significance for the implementation of the mechanism to resend short messages. Another theoretical innovation of this paper is combining the 8bit and 7bit coding scheme for monitoring data message and alarm message separately, whch takes full advantage of both coding schemes.Based on the theoretical analysis, a remote street lamp monitoring and control system for an avenue of Xiamen is developed. The system controls the status of the street lamps, monitors the line voltage and line current, and guards the wire against theft. This paper also gives a detailed introduction of the design and implementation of the system gateway.