The Study Of Image Transmission In CDMA System

Code Division Multiple Access (CDMA) has more advantages than other access technologies, so it has already became the core technology of the third generation wireless communication systems, but these systems are all interference-limited, the system performance and capacity is limited by the Multi-Access Interference (MAI). Multi-user Detector (MUD) is the key interference cancellation technology of the wideband CDMA communication system. Video communication is the hotspot in the computer and communication area. With the development of the computer technology, network communication and multimedia technology especially the video compress technology, the video compress technology, the video transportation will be the important service on the wireless communication area. CDMA communication system is the strong mode in the future. The research on transmission of image and video signal based on CDMA communication is significant.The work of this thesis is a part of the Nature Science Research Project of Anhui Education Department, "Research on the optimization algorithms of NP-hard problem in CDMA multi-user detection with large user numbers", deals with MUD problem with a kind of typical Decor. And we investigate application of the Maximum a Posteriori (MAP) decoding approach to image transmission over AWGN channel. Based on their basic structures, some improvements and according application method to these algorithms are proposed according to the practical problems emerging from image transmission in CDMA communication systems, the validity of these algorithms has been proven by case studies. The main content in the research of this thesis includes:1. Analysis of the MUD problem in CDMA communication systems,studying it from the direction of computational complexity.2. The evolution of digital mobile communications along with the increase of integrated circuit complexity has resulted in frequent use of error control coding to protect information against transmission errors. This paper investigates application of a MAP decoding approach to Joint Photographic Experts Group (JPEG) image transmission based on CDMA communication. Analyses and simulation results show that our approach has obtain satisfactory image quality and effect from take-over port.3. The application research of Wavelet-based image compression is becoming mature as the Wavelet theory research proceeds in last decades. The paper investigates other application of a Wavele-Compressing image transmission based on CDMA channel. Analyses and simulation results show our approach has has obtain satisfactory image quality from take-over port, and make more rapid transmission.