Research On Timing Recovery On Impulse Radio Wireless Communication System And Implementation Of IR-UWB System

The Impulse Radio technology can provide huge bandwidth with low power spectral density, low complexity and low cost, which make it became a hot research area in wireless communications. Because of the short pulses time duration in IR system, it is necessary that IR system need to solve the acquisition of multi-path when recover the timing information. But the channel estimation needs the precise timing as well. This issue is a critical restriction of data rate and system cost in IR systems.Based on a novel OSCR receiver, this paper focuses on key technology of IR systems: path Pre-estimation, timing recovery technique, burst communications of IR systems with the aid of non-coherent method and Implementation of a high rate IR system.Pre-estimation of multipath. This technology is dedicated to solve channel estimation problem with no timing information. Notice that the output energy of the two orthogonal branches in OSCR receiver is only relate to the path amplitude and it is independent with the sinusoidal template, the receiver can use several windows to do a coarse estimation of the multiple paths. Then the receiver can choose several pre-estimated paths to recover the timing information.Timing recovery in orthogonal receiver. Multi-path pre-estimation provides very coarse path information. But it can't give the precise time offset between the path and the correlation windows. The correlation output of pulses and receiver template is so narrow that a tiny timing error will cause a drastic SNR degradation at the receiver. A synchronization method base on decomposed multi-path output of orthogonal receiver is introduced. By using the phase information of decomposed vector, precise timing information can be recovered.Burst communications of IR systems with the aid of non-coherent method. Coherent IR system needs a long time to achieve timing acquisition. A novel method is proposed in this paper. This method can achieve fast timing recovery and multi-path estimation, while it needs low system cost. This method is very promising in IR-UWB based wireless sensor network.Implementation of a high rate IR system. In this paper, a high data rate IR-UWB communications system is designed and implemented. The data rate is more than 100Mbps. Multi HDTV streams and files transmitting are demonstrated upon this system, showing that the system is stable and robust. This system is the first IR-UWB systems ever reported in the mainland.This paper mainly focuses on the topics mentioned above and the work has solved several key issues in IR-UWB systems. What's more, the solution needs low system cost and it can be implemented relative easily. The demonstration built up on this work proven its validity.