Design And Implementation Of The Physical Layer Communication Module In Ad Hoc Networks

With the rapid development of communication technologies,self-organizing networks have been widely used due to their flexible mobility,rapid networking,and strong adaptability to the environment,especially in places where there is no infrastructure support,such as emergency rescue and battlefield communications.The performance of network communication nodes plays an important role in the entire network.The existing Ad-Hoc network communication nodes gradually form some common modules,however,there are problems such as a single communication system,insufficient processing capacity,lar ge volume,and high power consumption.Therefore,the signal anti-jamming transmis s io n capability needs to be improved under the premise of satisfying the functional requirements of the system,and take into account the needs of modularization,high speed,and miniaturization.As a key technology of self-organizing network,software radio has features such as flexible functions,convenient upgrade and strong universality.Designing and implementing a new and efficient physical layer communication module in Ad Hoc networks has important research significance and application value.The dissertation first introduces the research background,significance and developme nt history of Ad-Hoc networks and software radios.Then,the design scheme of the baseband system of the communication module is proposed,and the key technical principles of the transmitter and receiver in the scheme are introduced.In the design,direct sequence spread spectrum communication is used as the communication method of the system,and a coding scheme is added to improve the system error correction capability.In the design of the receiver,the zero-IF receiver architecture is selected and the baseband receiver data is synchronized and demodulated using a zero-IF frequency-locked phase-locked loop.Then,the AD9364 and Altera Cyclone V chips are selected as the core module,and the hardware platform design scheme for the communication module is formulated.The device selection and function configuration of the main modules such as power management,power amplifie r,and RF switch are introduced.In particular,a two-stage low-noise power amplifier block is added to dynamically adjust the received signal strength.In the design of the hardware platform,the baseband processing board is separated from the radio frequency board,and the AB board design is used to simplify the device volume.Finally,draw the schematic of the hardware platform and complete the PCB board.The paper then implements the FPGA implementation of the baseband system of the communication module,and introduces the implementation method and process of key modules of the transmitter and receiver.Then,the program is downloaded to the FPGA and connected to the hardware platform with JTAG.Use the software's own signaltap program to verify analysis simulation timing.Then use a multimeter,spectrum analyzer,attenuator and other devices to test the hardware platform and measure the receiver sensitivity.Finally,the communication module and the upper layer network protocol development board are cascaded to form a network node,test the maximum service transmission rate of the node,and compare and analyze the node service transmission performance in differe nt environments.The design results show that the self-organizing network communication module designed in this paper has the advantages of miniaturization,high speed,integration and antiinterference,relies on flexible configuration of baseband signal processing algorithms,highly integrated modular hardware platform,and high-performance core processing device.It can achieve efficient and accurate transmission of information,strong scalability,and effectively reduce the device size and power consumption,has a good application and research value.