Design And Energy Consumption Optimization Of LoRa Scattering Communication

LoRa communication technology is an important branch of current Io T communication technology.It belongs to low-power wide area network communication technology.Compared with other Io T communication technologies,LoRa has Better application prospects for its higher receiving sensitivity and longer communication distance under the same power consumption.However,in ultra-low-power Io T application scenarios,power consumption of node is generally required to reach microwatt level,and the power consumption of LoRa transmission and reception is as high as tens of milliwatts,which is still too high to meet the application requirements.To solve these problems,this article has conducted an in-depth study on reducing the power consumption of LoRa technology.The main work is as follows:Based on the theory of scattering communication,this paper proposes a LoRa scattering communication method based on DDS-OOK modulation.This method uses DDS technology to synthesize a Chirp square wave containing standard LoRa signal components,and uses it to control the RF switch to achieve Scattering modulation of LoRa.Then a hardware system based on the method is designed and implemented.The experimental results show that the transmission power consumption of the LoRa scattering node is 2?3 orders of magnitude lower than that of standard LoRa,the standby power consumption is reduced by about 46%,and the receiving power consumption is reduced by about 76%.In order to further optimize the power consumption of LoRa scatter communication,this article firstly proposes a modified fixed time slot allocation algorithm based on the characteristics of the hardware system.This algorithm modifies the allocation strategies of sending and receiving in the traditional fixed time slot allocation algorithm,thus improves the energy efficiency of the system.Secondly,based on the feature that spreading factor of LoRa is adjustable,this paper proposes a adaptive data rate algorithm with average power consumption as the optimization goal.The algorithm uses the least squares prediction method to estimate the channel quality,and then adjust the spreading factor according to the channel quality to minimize the average power consumption.Finally,the above two algorithms were implemented on the MCU hardware platform for indoor experiments.The experimental results show that the average power consumption of the algorithms is up to an order of magninude lower than that of using fixed spreading factor,without average packet loss rate exceeding 5%.