The Multipaths Optimization Algorithm In UWB Receiver

As a new communication way, Ultra-Wide Band(UWB) technology is attracting more and more attention in the research region, which has low power consumption and high data rates. UWB is normally used in indoor environment communication, as there is many indoor barriers, the signals reach the receiver in the form of multipaths. The number of the multipaths is so enormous and the energy of per multipath is so low that the real system can't use all the multipaths components due to the complexity constraints, so the multipaths selection algorithm and the optimal combination algorithm, which also play key roles in the research of improving the performance of the UWB system, are needed.In this paper, the producing and modulation ways of signals are introduced firstly. Then the multi-paths channel model is provided, and the model of UWB communication system is built. Focusing on the UWB multipaths signals, the Discrete Particle Swarm Optimization (DPSO) Multipaths Selection algorithm(DPSO-MSa) is proposed to maximize the Signal to Interference and Noise Ratio( SINR ) of the system. At last, the comparision with conventional algorithm, suboptimal algorithms and Genetic Algorithm(GA) is carried. The results show that the DPSO-MSa is obviously better in SINR, speed and effect of looking for excellence than others.After the optimal multipaths selected, the multipaths should be combined with suitable weighting factors. In UWB communication system, the optimal linear Minimum Mean Square Error (MMSE) scheme in combination has excellent convergence, but requires inversion of matrix, which leads to computationally intense. Therefore, in order to reduce the system complexity, an improved MMSE algorithm, called MMSE-Multistep combination algorithm is brought out. At last, the comparision with Maximal Ratio combining (MRC), Equal Gain Combining (EGC), and convenitional MMSE is implemented. The simulation results show that MMSE-Multistep algorithm not only reduces the system complexity and Bit Error Probability(BEP) greatly, but also improves the ability of anti-MAI.