Design And Implementation Of Multi-channel Wi-Fi Signal Acquisition System

In recent years,with the development of modern wireless communication technology,Wi-Fi usage scenarios have become more and more extensive,and we are also surrounded by ubiquitous Wi-Fi signals.By monitoring and analyzing the Wi-Fi signals around us,we can get a lot of information and apply it,such as indoor positioning technology based on Wi-Fi signal detection.In special scenarios such as airports,the Wi-Fi coverage is large,the Wi-Fi environment around the aircraft is complex,and there are many interference sources.We need to track the movement of the target through the collection of Wi-Fi signals and perceive the interference of the surrounding Wi-Fi environment.Locate the interference source and obtain the surrounding channel information to select the appropriate communication direction and channel of the aircraft.This requires multi-channel acquisition of Wi-Fi signals in various directions around the aircraft to provide Wi-Fi in the airport scenario.The collection of Wi-Fi signals brings the need for multi-directional multi-channel acquisition.In response to this demand,this thesis designs a distributed multi-channel Wi-Fi signal acquisition system that can accurately monitor Wi-Fi signals in multiple directions simultaneously for spherical antenna arrays.This thesis first introduces the research background and significance of the multi-channel Wi-Fi signal acquisition system,and expounds the current research status at China and abroad.Subsequently,the main work of this thesis is explained.The main work and innovation of this thesis are as follows:(1)First,analyze the functional requirements and design indicators,focusing on the relevant constraints faced by the system design,and determine the overall design of the system.The key problems to be solved are:by analyzing the structure of the spherical antenna array,the design scheme of mounting the PCB board on one side of the spherical antenna array is determined,and the problem of the shape and size of the PCB board is solved;through the PCB board area,data transmission rate and The system power consumption and other constraints were analyzed to determine the maximum number of channels on the PCB.According to the functional requirements and design indicators,the STM32F103RC microcontroller module,power supply module,ESP32Wi-Fi chip module,serial port switching and mode selection module were determined.Hardware component module design,and software component module design including STM32F103RC microcontroller module,ESP32Wi-Fi chip module,serial port scheduling module,and clock synchronization module.(2)Complete the system hardware design and implementation related work.The main work includes STM32F103RC microcontroller module,power module,front-end acquisition chip ESP32Wi-Fi chip module and other module circuit design and PCB board design.The key problems to be solved are:the introduction of a grounded coplanar waveguide technology to solve the impedance matching problem of the ESP32 Wi-Fi chip RF input port wiring in the system,so that the transmission line width can meet the routing requirements;the introduction of multiplexers solves the S TM32F103RC The microcontroller switches the serial port between the front-end acquisition chip ESP32Wi-Fi chip on multiple channels and the work/programming mode selection of the ESP32Wi-Fi chip.(3)Complete system software design and implementation related work.The main work includes STM32F103RC microcontroller and front-end acquisition chip ESP32Wi-Fi chip internal programming.The key problems to be solved are:the serial port scheduling algorithm by group polling is designed to solve the scheduling problem of multi-serial port data transmission,so that the collected data can be efficiently transmitted on the serial port;drawing on the principle of IEEE1588 precise clock synchronization protocol,the design is of low complexity The clock synchronization scheme enables all front-end acquisition chips ESP32Wi-Fi chips on multiple channels to achieve clock synchronization with the microcontroller.Finally,the developed multi-channel Wi-Fi signal acquisition system was tested,and the test results were analyzed.The test results show that the multi-channel Wi-Fi signal system designed in this thesis can reliably collect Wi-Fi signal data on multiple channels and achieve clock synchronization on each channel,which is suitable for Wi-Fi signal collection in airport scenarios.