| Power Line Communication uses the existing power line network resources without re-wiring, greatly reducing the cost of communications networks. It is very convenient to group together the electrical equipments within a certain region by this means of communication. Gateway Design based on power line communication system is aimed to control the electrical equipment connected by the power line network and get data which will be shared them to the cloud via Ethernet, the public mobile communications network.According to the functional requirements, we first design the hardware circuit, then develop software program. In the aspect of hardware, the ARM chip is the core processor of communication gateway and the design includes high-capacity storage circuit, rich debug download interface circuit, network communication interface circuit, serial communications interface circuits, power line communication interface circuit and so on. The operating environment for software is the embedded Linux system, providing a wealth of low-level drivers and decreasing the developing difficulty.Communication Gateway acts as the bridge between cloud servers and control equipment, there are two ways to communicate with the cloud:(1) Ethernet networks, the clouds equipment and communications gateway are connected by cable. Combinating HTML, CGI technology with Web server to achieve the communication between the clouds and communications gateway, using B/S mode. The web interface not only communicate with the embedded Web server by TCP traffic, but also access to the embedded SQLite database, facilitating the downloading and applications of historical data.(2) Wireless networks, datas can be return to the clients, by communication gateway devices and the cloud through General Packet Radio Service (GPRS) technology. Client uses software provided by GPRS provider. The communication gateway and control equipment are connected together by power lines. Communication gateway control electrical equipment and read data command, which be sent to the electrical equipment through the power line channel transmission after the LDPC encoding and DSSS. The electrical equipment gets data after dispreading and decoding. The collected data are sent back by the power line communication gateways through the LDPC, DSSS. Communication gateway using the method which combining the DSSS despreading and LDPC decoding to process the received datas which will be stored in the database and returned to the cloud.Based on Linux embedded development platform, the paper implement the process of collecting meter data via power lines, and sharing data across the network to the cloud devices without wiring, which can control the electrical equipment easily and quickly. |
