Research On LPWAN Energy Saving Technology Based On LoRa

With the rapid development of Internet of Things technology,people need to realize the connection between people and things and things at any time and place,which puts higher requirements on the power consumption and communication distance of network equipment.Low-power wide area network(LPWAN)technology is a newly emerging Internet of Things access technology in recent years.It has features such as low power consumption,long communication distance,and low cost.Compared with existing technologies such as WiFi Bluetooth and Zig Bee,the LPWAN truly implements wide area coverage.LoRaWAN is a typical representative of LPWAN.It is a Low-Power Wide Area Network specification based on LoRa technology and is applicable to wide-area networks using terminals powered by batteries.LoRaWAN targets the critical needs of the Internet of Things,such as secure two-way communications,mobilization and localization services.The standard provides seamless interoperability between smart devices,does not require complex local installations,and gives users,developers and companies freedom to use them in the Internet of Things.As the mainstream technology of the future low-power wide area network,LoRa network has been widely studied.Although LoRa WAN uses physical layer technology to provide low power consumption,the energy consumption of battery-based network endpoints still faces significant challenges.The energy saving problem of network terminal nodes has always been one of the most important issues in the research of LoRa networks.This article focuses on the low-power design of the LoRa terminal.In this context,this article has carried on the research to the low power consumption design scheme in LoRa system,mainly includes:The main research contents and contributions of this article are as follows:(1)From the perspective of LoRaWAN protocol,the structure of Lo RaWAN physical layer,MAC layer and protocol stack,and LoRa network structure diagram are studied and analyzed;and the energy consumption of the three operating modes of LoRaWAN is analyzed and compared,and the security mechanism and retransmission mechanism of LoRaWAN protocol are compared.The LoRa terminal's adaptive mechanism(ADR)performs analysis.(2)A dynamic prediction algorithm for maximum transmission rate of LoRa terminals based on neural network is proposed.The algorithm is based on the neural network model.The LoRa server performs dynamic prediction of the maximum sending rate of LoRa terminal and informs the terminal of its input parameters RSSI(signal strength)and SNR(signal-to-noise ratio).The terminal can finally meet the requirement of ensuring normal communication and transmit at the maximum rate to achieve low power consumption.(3)The DTOP(Dynamic Turning Off the Ping time-slots)mechanism that LoRa terminals dynamically shut down redundant ping timeslots is proposed.This mechanism can achieve low power consumption by turning off LoRa terminal unnecessary receive window in LoRa Class B mode.Test results and theoretical analysis show that the energy saved by the algorithm is positively related to the number of closed ping timeslots.Test results show that 80 mJ of energy can be saved within 30 minutes test.(4)The DSAB(Dynamic Suspension Accepting Beacon)mechanism is proposed that the LoRa terminal dynamically suspends accepting Beacon frames.In the LoRa Class B mode,when the server has no data to send to the terminal,the LoRa terminal can close the Beacon frame reception windows to reduce the power consumption of the LoRa terminal.Test results show that 65 mJ of energy can be saved within 30 minutes test.