Design And Implementation Of FBMC Modem

The orthogonal frequency division multiplexing system with offset quadrature amplitude modulation(OQAM-OFDM) is now a recognized alternative to the conventional OFDM system for the data transmission over multipath fading channels, and it’s the one of Filter Bank Multicarrier(FBMC) which is the Multi-carrier modulation scheme of fifth generation mobile communications. By selecting a pulse shaping filter with a good Time Frequency Localization(TFL), inter-symbol interference(ISI) and inter-carrier interference(ICI) can be limited in a reasonable range without cyclic prefix(CP) in OQAM-OFDM. Compared to the conventional OFDM, OQAM-OFDM has some advantages such as stronger immunity to ISI and ICI, avoiding of CP and lower out-of-band radiation, it has a strong potential for development. This paper focus on the design and implementation of OQAM-OFDM modem by referring to the physical layer in 802.11 a standard.Firstly,this paper introduces the basic principle of OFDM system, researches on the basic principle of OQAM-OFDM system, and introduces two approaches to achieve the OQAM-OFDM system based on FFT/IFFT, i.e., frequency spreading(FS) and polyphase network(PPN). In the end, we select the Frequency Spreading Filter Bank Multicarrier(FS-FBMC) as the implementation scheme of OQAM-OFDM modem by comparing the performance of sub-channel equalization.Second, with the rapid development of field-programmable gate array(FPGA), its strong real-time and parallel processing capabilities to make it possible for real-time signal processing. Therefore, this paper will design and achieve the OQAM-OFDM modem based on FPGA.Finally, this paper implements each module of OQAM-OFDM modem using the IP core provided by Altera and Verilog Hardware Description Language, including the QPSK mapping and demapping, OQAM modem, frequency spreading and frequency dispreading, IFFT and FFT, Overlap and Sliding Window modules. We do RTL simulation for every module utilizing the integrated development environment Quartus Ⅱ, simulation tools ModelSim and Matlab, and verify the correctness of each module. At last, we will complete the design and implementation of FS-FBMC modem on the hardware platform of Altera Stratix 5SGXMA7K2F40C3 Development Board.