Study On Key Technologies Of Narrowband Internet Of Things Physical Layer

Communication between things is gradually realized with the rapid development of information technology.Various IoT solutions that meet the needs of different demands make the world connected as a whole.Narrowband Internet of Things(NB-IoT)has gained people's favor in the IoT market due to its unique features such as,wide coverage,low power consumption,massive connections,and low speed.It is especially important to study the NB-IoT physical layer channel technology in order to realize the wide coverage function.This thesis is constructed as follows.Design of channel transmission time optimization method.This thesis studies the NPUSCH format1 link transmission and reception process and tests block error rate of UL-SCH blocks in different SNR conditions.Moreover,a channel transmission time optimization method is constructed based on this link simulation.The least transmission time can be achieved by this method during a specific SNR range with the limit of UL-SCH blocks BLER?10%.Design and verification of uplink time-frequency resource scheduling algorithm.This thesis comprehensively analysis the change of repetition times,bandwidth and MCS`s influence in coverage performance.An uplink time-frequency resource scheduling algorithm is designed based on the results.Simulation result shows that UE can be covered by adjusting the adaptive parameters when the MCL reaches164 d B.Study on system-level NB-IoT coverage performance.This thesis also builds NB-IoT PHY and MAC layer modules in NS-3 simulator in terms of protocol stack to meet the requirements of data transmission as well as interface functions and classes between layers.Typical wireless environments like urban suburban and open area are constructed with the help of Okumura-Hata propagation loss model.In order to plan the radius of different wireless environments,link budget is performed.What`s more,this thesis designs single parameter optimization and hybrid parameter optimization methods in the scene to analyze terminal coverage in the cell in different environments.Finally,capacity model is constructed and plan the capacity for NB-IoT applications like Smart Metering.Results show that the NB-IoT application model designed in this thesis can effectively cover the cell radius planned in this thesis,and the system capacity has reached the actual application requirements.