| After decades of development,Io T technology has penetrated into all walks of life,greatly improving social production efficiency and people’s living standards.However,there are still many scenarios limited by the contradiction between "performance and power consumption" in the Io T sensing system,which makes it impossible for existing Io T sensing technologies to cover them.Specifically,strong terminal nodes that use Wi Fi,Lo Ra,and other communication technologies based on superheterodyne transceiver systems are limited by excessive power consumption and lead to high maintenance costs,making it difficult to adapt to large-scale deployment of sensing scenarios.However,weak terminal nodes using backscatter communication technology reduce the power consumption of terminal communication to the microwatt level,but inevitably introduce problems such as short-distance communication and channel conflicts,and it is also difficult to adapt to long-distance and large-scale sensing scenarios.In order to solve the contradiction between "performance and power consumption" in the Internet of Things system,and to meet the purpose of long-distance,large-scale,and large-scale sensing scenarios,this study designed Zeros,a zero-power sensing terminal and its network system.Zeros floats the control operation of the sensor to the gateway,realizes the sensor terminal without a processor,and reduces the power consumption and cost of the terminal.Starting from the three aspects of downlink communication,uplink communication,and sensor control logic,the "low-power spread spectrum communication system","long-distance backscatter communication",and "processorless data link layer protocol" are systematically studied.Under the premise of maintaining low power consumption,improving the wireless communication performance of weak terminals has reached a new balance point in the contradiction between "performance and power consumption" in the Io T system,and provides strong support for expanding the application scenarios of the Io T sensing system.Specifically,the research content of this paper is as follows.(1)In view of the contradiction between downlink communication distance and power consumption of weak terminals,this paper floats part of the despreading calculation in direct sequence spread spectrum communication to the gateway,realizing passive direct sequence spread spectrum communication,while keeping the non-coherent receiver low The characteristics of power consumption increase the downlink communication distance at the same time.(2)Aiming at the short-distance and channel conflict problems of backscatter communication,this paper realizes distributed CSS uplink reflection communication,and realizes parallel communication while improving the anti-interference performance of uplink communication.At the same time,starting from the principle of Chirp signal demodulation,a The high duty cycle backscattering system increases the energy intensity of the reflected signal after demodulation and further increases the uplink communication distance.(3)Aiming at the problem that weak terminals without processors cannot respond to complex network instructions,resulting in increased network delay,this paper designs a simple data link layer protocol and the corresponding state machine,which realizes the broadcasting and grouping of gateways to terminals.Broadcast and unicast,combined with parallel uplink communication technology,can greatly reduce network delay.Under this agreement,the gateway can control multiple sensors on the processorless terminal,increase the function of the processorless terminal,increase the flexibility of the processorless terminal,and further expand the application scenarios suitable for the Zeros system.Finally,this paper implements the corresponding prototype system.After testing,the Zeros system can accommodate 256 independent channels within a 1MHz bandwidth,and at an uplink communication rate of 1kbps,it can achieve a maximum bilateral peer-topeer communication distance of 310 meters,and the required power consumption is only231.541 microwatts,which meets the needs of the definition of "zero power consumption" by the industry and research institutions. |
