Design Of ESAM-Based Prepayment Terminal Unit With Wireless Sensor Networks

With the development of social economy and increasing progress of science technology, in the public utility domains such as water, electricity or gas etc., the charge way takes a shift from manual meter reading to automatic meter reading. Effectively, the latter way avoids the problems such as less, lack or wrong reading, corruption and low efficiency and so on which are brought out by the former way, realizes the automatic delivery function of billing data and improves the automation level of public utility management. Nevertheless, tardy charge issue can not be settled. Then IC-medium pre-paid model occurs in the electricity charge field to form a "use after payment" model, however the model is short of link for meter reading. To acquire the billing data for analyzing timely, a scheme for meter reading should be designed in addition.In this paper, wireless sensor network was applied in the design of prepayment system in Intelligent Community. A string-like network is formed basing on deployment knowledge, when terminal acts as sensor nodes for metering and storing the user balance and management master as the sink node for meter reading and recharge management. The data of network is transmitted in the encryption modality realized by the keys and TripleDES arithmetic saving in security module embedded in the nodes to achieve network meter reading and pre-paid function securely. The details are as follows:Firstly, it introduces the research background and the current development of energy prepayment and AMR(remote meter reading) at domestic and abroad simply, and expounds disadvantages existing in the current IC card prepaid mode. Then describes the architecture, node structure and characteristics compared to the traditional wireless network of WSNs, analyzes security threats and determines safety design goals and design ideas. And then it studies the security mechanism of embedded security access module whose internal structure and management mechanism were analyzed. Subsequently, on the premise of giving the overall design of the network prepaid system, it focused on the hardware design of user terminal, relay terminal and management master, including units of microcontroller with PIC16F727chip, security management withLKT2102, wireless communication with CC1101, storage with FM24CL16A chip display with LCD12864and communication interface with MAX3232chip to upper compute and so on. Then the file structure of embedded security module and issue apparatus were designed. The keys of WSNs are managed by embedded security module and can only be used under some limits of authority. With the security mechanism, wireless network security objectives such as the confidentiality, integrity, fresh, as well as security authentication of transmission data are guaranteed, and then the security algorithms and program were designed to accomplish the functions of remote meter reading and pre-paid recharge.ESAM-based and wireless sensor network-based pre-payment terminal in this project can prevent the leakage of security messages separating the design of key information and device develop. The design can be used in the field of water, electricity, gas or heating and other prepayment within the Intelligent Community to realize remote meter reading and pre-paid in security.