| Ultra-wideband (UWB) is a hot issue researched in the field of information recent years.new techniques are instantly emerging, and the DS-UWB, OFDM-UWB system, which isnon-carrier or modulated carrier, have been formed in the field of communicationapplications,but the Research is just beginning in China. With the emergence of more andmore new wideband wireless communication technology, it is difficult to overcome thewireless channel. The work of overcoming it calls for understanding channel modeling well.Channel modeling is based on understanding the channel of band well.Every pulse in the UWB (Ultra-wideband, that is, UWB) signal need a big bandwidth,the maximum data transfer rate can reach more than100Mbit/s, and also have some virtuessuch as low interception rate/low rate of detection, anti-multipath, simple logic stucture,Has a strong penetrating power and can identify the hidden object or something movingbehind the wall, has high-resolution (ns level), can provide high positioning accuracy; At thesame time, the transmit power of UWB devices is very small, but the peak of transientpower will be big because the Pulse duration time is very short, the bandwidth of the wavewill be large, and will have a broad developing space under the condition that it don’tinterfere with other existing communication system and could co-exist friendly with other airinterface waveformChannel is road which realize the transmission between the information source anddestination by transmission medium or material, research for the characteristics of UWBcommunications channel is crucial for the successful design of UWB communications system,But UWB indoor channel modeling is an undetermined question.The study is help forselecting UWB PHY standards, help for asseting system performance and link budget. Andthe study will quicken the step of civil and commercial application.Taking the non-carrier ultra-wideband communication systems for example, this workresearched the transmission properties of UWB signal in Typical indoor environment,described the UWB indoor channel theriotical model, including the path loss models andmulti-path channel model which is divided into frequency-domain model and time-domainmodel, introduced all kinds of typical channel models, especially S-V model and theimproved model presentation IEEE802.15.3a, by simulation we explored the characteristicsof impulse in the typical indoor environment under the AWGN channel model and IEEE802.15.3a channel model and the characteristics of UWB-IR System;The resultsindicate:1. the power of the signal exponentially decreases with the increase of the distance;2.the Pass Loss decreases with the increase of signal frequency. The simulation ofIEEE802.15.3a standard channel model is carried on in four situations according to theenvironment and the distance between the transceiver.The result indicates that the declinecharacteristic of the cluster and the ray in the cluster match well with the measured data.Theresearch on the simulated model can provide direction for the design of UWB system. Thework done in this thesis and conclusion of the simulations are gathered in the last section. Thedirection for future study is put forward as well. At last, the summarization of the thesis isgiven. And the future study direction is also pointed out. |
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