System Design And Key Technology Research Of NB-IoT Operating On Unlicensed Spectrum

Introducing Internet of Things(IoT)technology to unlicensed frequency band is one of the important candidate solutions for the fifth generation mobile communication system to enable massive connection scenario of IoT devices.To this end,the MulteFire Alliance(MF)has established a standard project for the Unlicensed Narrowband-IoT(NB-IoT-U)technology which can be deployed in the Sub-1 GHz unlicensed band.Based on the FCC and ETSI regulations,MF has designed a specific hybrid frame structure for NB-IoT-U.This thesis investigates some key technologies related to the frame structure in the NB-IoT-U system,which aims to solve the problem of frequency hopping selection of the data channel in the NB-IoT-U system,improve system coverage,and reduce the delay of system access.The main contributions of this thesis are summarized as follows:(1)Aiming at solving the problem of frequency hopping of data channel in the NB-IoT-U system,based on the design idea of the frequency hopping channel selection kernel algorithm in the Bluetooth system,this thesis proposes a frequency hopping channel sequence generation algorithm which is suitable for NB-IoT-U.(2)In order to enhance the synchronization detection performance of the NB-IoT-U system and shorten the synchronization delay,based on the 3GPP NB-IoT synchronization signal transmission scheme,this thesis focuses on the transmission of Unlicensed Narrowband Primary Synchronization Signal(NPSS-U)and Unlicensed Narrowband Secondary Synchronization Signal(NSSS-U)transmission in NB-IoT-U system,and proposes enhanced design schemes.(3)To improve the coverage while reducing system access delay,the Master Information Block(MIB)and System Information Block(SIB)transmission schemes are proposed based on the frame structure of the NB-IoT-U system.The above solutions proposed for the NB-IoT-U system in this thesis have been verified by simulation.Results show that the proposed schemes can meet the requirements of NB-IoT-U and yields better performance than 3GPP NB-IoT.