Research And Design Of Packet Binary Convolutional Coding In IEEE802.11b

The wireless local area network(WLAN), which meets people’s demand to buildbroadband wireless network at anytime and anywhere, has become an important part ofpersonal wireless communication now and in the near future. Packet binary convolutionalcoding(PBCC),one of the key modulation technologies in IEEE802.11b, can achieveappreciable coding gain without increasing in bandwidth and decreasing in informationtransmission rate thus making the most use of bandwidth and power simultaneously througheffectively combination of convolutional coding and modulation.This paper first researches the modulation and demodulation algorithm of PBCC anddesigns the PBCC baseband modulation and demodulation system. Then the performance ofViterbi decoding and different quantization methods in the baseband demodulation aresimulated in MATLAB, which paves the foundation for hardware design.With the use of Verilog HDL, the paper designs an improved FPGA-based PBCCmodulation and demodulation system at data rate11Mbps, which focuses on designing theViterbi decoding module, the part of overflow handling uses modulo normalization and thepart of storage surviving information uses a RAM ping-pang to read and write in the Viterbidecoding module, thus reduces the hardware resources significantly. Finally, the system isfunctionally simulated in Quartus II and tested on the FPGA platform. The data rate in thesimulation fully meets the requirement in the protocol.