Research On Random Access Optimization For Small Data And Low Power Cellular IoT Scenarios

With the rapid development of the cellular IoT,a large number of IoT terminals have been flooding into the cyberspace.These IoT terminals are rich in variety and play a role in different fields.In order to provide appropriate wireless access services for IoT terminals,researchers have proposed different requirements of data rates,access densities,coverage areas,power consumption,and lantency for wireless access technologies based on the scenarios of the terminals' services.To meet these requirements,a suitable wireless transmission solution needs to be designed.In the current cellular IoT transmission solutions,the random access process is the first step for a terminal to access the network,and it mainly carries through uplink synchronization and access control.With the requirements of emerging scenarios,the existing random access process may not function properly.Therefore,it is necessary to optimize the random access process according to the requirements of the new scenario.The main work of this thesis is to design a kind of random access process for transmitting uplink and downlink data(EDTP random access process)based on the characteristics of low mobility,small data,large access density,wide coverage and ultra-low power consumption of the most common sensor terminals in the cellular IoT.The basic idea of EDTP: the terminal completes registration in the network,and the network suspends the terminal session.When the terminal needs to transmit small data,the session is resumed in the network.The terminal uses Msg1 for random access to transmit uplink data or signaling,and uses Msg2 to transmit control signaling or downlink data.The terminal does not need to perform a complete random access process and a session establishment process through the EDTP process,which reduces the work time of the wireless module,thereby reducing power consumption.At the same time,the steps of random access are reduced,thereby reducing overhead of wireless signals and improving channel utilization.Based on the NB-IoT protocol,a systematic simulation of the EDTP random access process was implemented through MATLAB.Systematic simulation functions include: basic functions of the physical layer,MAC,and RRC of the terminal and the base station,the interface between the base station and the core network,user data generation and recording of cloud server and terminal,basic functions of core network,multipath and noise of wireless channel.The simulation and comparison with the existing initial session access and EDT process verify the superiority of the EDTP random access process in power consumption,wireless resource utilization,and system throughput.