Research On Channel Models And Channel Estimation Techniques In UWB Wireless System

With the development of semiconductor technology and the popularity of network technology,a variety of intelligent devices become more and more popularity in the popular life.Short distance wireless communication technology with characteristics of miniaturization,low cost,energy saving,high-speed become more popular.Benefits to UWB wireless communication technology's unique advantages,people's needs could be satisfied.Although UWB technology has been open to the civilian sector at the beginning of this century,the main achievements are limited in the area of Indoor Position.The progress in wireless communications is less relatively,Because of technical problems such as detection and reception of signal,synchronization between the transmitter and the receiver,channel modeling and estimation in the application of UWB wireless communication technology,the progress in this area is less relatively.The research of this paper is mainly about the channel models and channel estimation in UWB system.Reviewed the development of UWB technology,the development of UWB channel modeling and estimation can be divided into three stages.The first stage is the exploratory stage.At this stage,the research on the UWB channel modeling is mainly based on the transplantation of the prior models;The second stage can be called the standardization stage,because the advantages of the application of UWB technology,many enterprises and institutions invest a lot of manpower and resources in its research in order to seize the initiative,which promoted the development of this stage;We are now in the third stage,is a continuous evolutionary stage.Firstly,the propagation characteristics of UWB signal are introduced.Then,the development of channel model in UWB wireless system and the SV / IEEE 802.15.3a reference model is introduced.Compared with traditional narrowband or broadband systems,the fading characteristics and channel sparseness of UWB systems are different.Two kinds of UWB indoor system modified models are introduced to avoid the shortcomings of S-V / IEEE802.15.3a reference model.Channel estimation techniques can be divided into several aspects,from time domain or frequency domain and structured or unstructured.Some common estimation methods are compared,and a new method is proposed.This method has ability of resistance,that is,the blind UWB channel estimation method based on FOS.The traditional UWB channel estimation algorithm has a common,that is,the need for high-speed sampling of the signal,but because UWB signal bandwidth is very large(> 500MHz),it's difficult for the current ADC technology to supporting this technology at low cost.The emergence of compressed sensing theory makes it possible to sample under a low rates.In this paper,the theory of compressed sensing is introduced in detail,including its theoretical framework,design of observation matrix and signal reconstruction algorithm.Then,the UWB system based on CS theory is modeled and OMP channel estimation algorithm is introduced And then improved the signal reconstruction algorithm based on the OMP algorithm.Simulated both of them,analyzed them synthetically by combining the performance and operation time.