Research And Implementation On Baseband Signal Processing Of Broadband Frequency-Hopping Transceiver

The carrier of the transmitted signal is constantly changing in frequency hopping communication.Compared with the conventional fixed frequency communication,it has good performance in signal anti-interference,anti-interception performance and multi access networking ability.Based on a burst mode FH communication system,this paper focuses on the baseband signal processing technique in wideband frequency-time hopping(FH-TH)transceiver,and implement the baseband algorithm on the hardware platform.These efforts have supported the networking of nodes.The major work of this thesis consists of four parts:Firstly,According to the technical requirements and signal characteristics of broadband frequency hopping transceivers,the baseband signal processing scheme of the transceiver is proposed,and the overall structure of the transceiver is designed.Secondly,a multi-phase filter channelized receiver structure for time-frequency signals is designed which considers the full probability of receiving broadband frequency-hopping signals.The channelized structure can not only ensure the reception of signals from multiple frequency points,but also has more advantages over the traditional parallel digital down conversion channelized structure in terms of its computation and resource consumption.The feasibility is verified by simulation.And then,the GMSK demodulation algorithm and FH-TH pulse signal acquisition algorithms are studied.Considering the low complexity of GMSK demodulation,the demodulation algorithm of limited amplitude frequency discrimination detection,differential phase demodulation and Viterbi demodulation algorithm based on differential phase are studied.The difference of demodulation performance is compared through simulation.The one bit differential demodulation algorithm for the receiver is selected according to performance,complexity and resource consumption.For the requirement of parallel acquisition of multiple time-frequency patterns,the acquisition algorithm of time-frequency pulse signal is designed,which improves the detection performance of patterns and simplifies the complexity of acquisition algorithm.The acquisition performance is analyzed by theory and simulation.Finally,The baseband signal processing module of wideband FH transceiver is designed on FPGA hardware platform,including data framing module,GMSK modulation and demodulation module,channelized receiving module and so on.The accuracy of the input and output waveforms of the module is verified by the simulation software.The design rationality of transceiver is verified on the hardware platform,which can meet the design specifications.