A General Hardware Platform For Multi-mode Modulation And Demodulation

Internet of Things(IoTs)has become another information technology revolution after Internet.Its exemplary applications in smart home,logistics,healthcare and other fields have promoted the rapid development of IoTs techniques.Among them,the wireless communication technology suitable for the Internet of Things is getting more and more attention.Different application scenarios need different wireless communication mode.In order to realize the interconnection of all things,the modulation and demodulation platform which adapt to different communication technology standards and support multi-mode has become a research hotspot.In this thesis,the QPSK,BPSK and 2FSK modulation and demodulation system are integrated into the same general hardware platform to meet the needs of IoTs.For the demodulation part,a unified synchronization mechanism is proposed.The traditional Costas loop can not cover all the phase error,the mechanism improves the traditional Costas loop’s phase detection structure,so that the phase error range can cover from-90° to 90°.At the same time,a phase rotation method based on training sequence to eliminate the system phase ambiguity is proposed.This method can be applied to the coherent demodulation of various modes,and it has a high versatility.Then,in the process of the hardware implementation of the modulation and demodulation system,the optimum design method of the modules is analyzed.Through the hardware sharing,the structure of the modulation and demodulation of each mode is unified,and the different modes can be converted instantly.In the experiment,the hardware platform of single BPSK,2FSK and QPSK was realized based on FPGA.The hardware resource consumption was compared between them and general hardware platform,and the average optimization reached 56.09%.The operating frequency is up to 202.36 MHz,and the base band data transmission rate can be adjusted from 4.8kbps to 20 MHz.