Remote Controlled Coding And Decoding System Design To Multiple Objects Based On CDMA

With the widely used of remote control system, and the increased of system controlled-goals, using codec controlling the different goals has became the integral part of the hole control system.At present, because of the controlled equipment's type and number more and more, there are some problems including serious interference in communication of remote target and low spectral efficiency. The article research the problem for the interference of many objectives'communication. According to the requirements of remote control system, the article design multi-objective remote control system using CDMA. The system uses combination of the OVSF code and GOLD code for providing different address and channels of base station in control system. At last, it decodes for reducing multiple access interference using multi-user detection technology the system finishes the function of multiple goals'control by encoding and decoding modules.The article describes the structure of the remote control system based on CDMA, and then the remote control system is studied. In the overall design of the remote control system, Communication protocol and frame structure is designed for the communication requirements of remote telemetry system. Design of the frame structure has two main parts, including system frame and wireless frame. By function, three different of the physical structure of system frames is designed to transmit different data, including the data frame, control frame, response frame. The wireless frame provides the structure of wireless transceiver data block, spreading code type, spreading gain, duration of each frame, transfer rate and other parameters. By the design of frame structure, the wireless communication's structures of remote control system are implemented in the paper. In the system,the design and function of codec is completed ,including clock module, channel coding and decoding module, check modules, spread spectrum encoding and decoding module. In Altera's Quartus II platform,based on the use of Verilog HDL language, schematic entry method and the DSP Builder technology, the important part of the encoder in remote control system is completed. In addition, the design by waveform simulation is tested. the function of multi-user detection module in the Nios II is completed to achieve constant modulus algorithm for multiuser detection.Finally, the paper completed the simulation and debugging to the codec module of remote control system.