Research On Key Issues Of Emergency Communication System

Emergency communication is used in the face of natural disasters or deals with sudden mass incidents, to ensure the emergency communication which establish a temporary communication network. According to the characteristics of emergency communication places,it needs to consider the compatibility and expansibility of the system when we design the physical layer system,which is also the key issue of this paper.Since based on FPGA’s Software radio design method with high flexibility,this paper propose hardware solution based FPGA which is used for solving the emergency communication system scalability problems;Communication algorithm based on software radio solve the compatibility of the emergency communication system.Finally this paper uses software radio design method based on FPGA to design physical layer of communication system.This thesis firstly introduces the existing emergency physical layer communication solutions, and analyzes the existing solution’s advantages and disadvantages.Putting forward solution of the emergency communication system physical layer which involves communication algorithm designing and hardware system designing. The communication algorithm is designed based on Xilinx System Generator and Verilog HDL.The System Generator is responsible for signal shaping, signal interpolation, modulation, coherent demodulation, carrier synchronization and bit synchronization. Verilog HDL is responsible for signal differential encoding, differential decoding,serial to parallel conversion,parallel to serial conversion, assembling frame,frame Synchronization.Due to the adoption of the software radio designing, the communication algorithm can change work frequency according to the field of environmental and ensure the compatibility of communication system.The system hardware platform using FPGA as the core board, using high-speed ADC and DAC to connect RF module.System provides gigabit Ethernet port and usb port, also provide high-speed FMC interface with other board interconnection which enhances the hardwave expansibility.This design adopts QPSK modulation for digital communication method,2Mbps rate of communication and signal bandwidth is not more than3MHz.So meeting the requirements of system design.