The Research On Key Tchnology Of Physical Layer In IEEE 802.11a-the Realization Of FIR Filter And Viterbi Decoder Based On FPGA

WLAN (Wireless Local Area Network) is the important part of future mobile communications system. In order to meet the need of accessing flexibly the Internet with high rate at great ease, WLAN is being researched and established around the world. WLAN features mobility, low cost and wire line failure free.This project does a lot of research work about IEEE 802.11a, which is the main protocol of WLAN. OFDM system, the Physical Layer in WLAN, is implemented by using FPGA (Field Programmable Gate Array), which is IP (Information Patent) and is prepared for ASIC. This project is supported by the bureau of the Tianjin Information Office's "The Implementation of The Key Technology in Broadband WLAN".After carefully studied and analyzed the protocol, we proposed a practical way to realize the Physical Layer in IEEE 802.11a. Lots of efforts have been contributed to the algorithms and architectures of the FIR module and (2,1,7)Viterbi module, which are the key component in 802.11a base-band process. To fit in with the high-speed request of Viterbi decoder in WLAN, a novel parallel architecture of Viterbi decoder is proposed in this paper. The paper also gives the realization approach of how to arrange the architecture of RAM, which focuses on the point of path management, and puts forward a new double trace-back algorithm. And theory study and experiment result prove that the decoder can be structured simply and has higher speed.This paper simulates the FIR module and Viterbi module with QuartusII, the results of function-simulation and timing-simulation both prove the proposed method is right.