FPGA Implementation Of The Key Techniques For OFDM WlANs

Wireless Local Area Network (WLAN) will become one of the important parts of mobile communication system in the future. Without wires, WLAN is of a good deal of merits, such as high mobility, low cost, little circuit troubles and so on. It is being developed and applied more and more widely. OFDM technology has many advantages, such as robustness against multipath fading and high bandwidth efficiency, which are suitable for the high-rate data transmission in wireless environments. Accordingly, OFDM is one of the preferred techniques in WLAN. IEEE802.11a,IEEE802.11g and IEEE802.11n are all based on OFDM. As OFDM becomes more and more widely applied in the next generation of telecommunication technology, the research and implementation of the key techniques of the OFDM for WLAN is valuable.Some basic conceptions of WLAN, the standards involved, and the principle of OFDM system are introduced. The OFDM frame structure and system parameters based on the IEEE 802.11a and IEEE 802.11n specifications are described. The key algorithms in the OFDM systems are analyzed. Then, with VHDL description, a 64-point block-floating point complex FFT module, a (2,1,7) convolutional encoder and Viterbi decoder module, and a packet detection and synchronization module are implemented on Xilinx ISE10.1 and SPARTAN-3E FPGA platform. All of them are suitable for IEEE802.11a and IEEE802.11n. The modules are simulated, synthesized, and downloaded.