Research On Turbo Iterative Detection And Key Technologies In Mobile Communication System

With the number of subscribers increasing and service requirements diversified, universal telecommunication system overrides the current mobile telecommunication system, which can not satisfy the diverse requirements. Therefore, UMTS and the future mobile communication systems providing large system capacity and multimedia service capability have absorbed much attention.To combat the current technical obstacles, several key techniques in receiver of future mobile telecommunication system have been innovated in this dissertation, and the purpose is focused on the application of MIMO-OFDM technology, high efficient channel coding technology, space-time coding technology, multiuser detection and iterative detection, and so on.Turbo principle, derived from Turbo-codes, has been broadly applied to coding and signal processing area. The main jobs in this dissertation has been emphasized on the key technologies of iterative detection based on a "Turbo principle", such as in coded MIMO-OFDM systems, coded DS-CDMA multi-user systems, space-time block-coding multi-user systems, multi-user MIMO-IDMA systems, and has proposed the innovative receiver architectures, simulated and anylized the detection algorithm, and its' performances and complexities. The main works include:The research on the turbo principle and iterative multiuser detection technology: In this part, an overview about the orgin of turbo principle, the concept, transmission model is presented firstly. And then several commonly applied and newly proposed algorithms of iterative detection are introduced, and the application of turbo principle are described in this part; and focusing on the iterative multiuser detection technology, the principle, the technology characteristic, and the system model, the commonly applied detection algorithms and the future development trend are emphasisedly researched.Reduced-Complexity Iterative receiver for Turbo Coded MIMO-OFDM Systems: MIMO-OFDM system is a good choice for high-speed data transmission, which can enlarge the system capability by enhancing the capacity of both the space complexing technology and OFDM technology. In this part, the theory, characteristic and system model of the MIMO-OFDM systems are reviewed firstly. Then high performace detection technology for turbo coded MIMO-OFDM systems is researched to mitigate error propagation, and a receiver infrastructure and a low-complexity iterative detection algorithm are derived. When algorithm processing, extrinsic information is extracted from the detector and the channel decoder in each iteration, and then used as the prior information for the next iteration to realize iterative channel equalization and channel decoding to make full use of the known information. The novelty of the proposed algorithm is to model the receiver signal vector as Gaussian random vector, and get the mean and variance of the detection signal to obtain the optimization. The simulation results...