FPGA IMPLEMENTATION OF OFDM TRANSCEIVER FOR IEEE802.11A WIRELESSLAN

Orthogonal Frequency Division Multiplexing, OFDM, technology is generally used in lots of high datareception communication systems, such as Digital Audio Broadcasting (DAB), Power Line Communications (PLC), and satellite communication systems. In some WLAN specifications, e.g. IEEE 802.11a and Hiper LAN in European, or WiMAX (i.e. IEEE 802.16e, 2005 for mobile edition) in metropolitan networks, OFDM techniques are also applied. In broadband wireless communication, the delay spread caused by channel multi-path fading will usually introduce serious Inter-Symbol Interference (ISI) to the receiver. To counteract the ISI, the high-efficiency Orthogonal Frequency Division Multiplexing (OFDM) modulations first splits the high-rate data stream into a number of parallel sub-streams and modulates them onto different orthogonal sub- carriers and thus lower the symbol rate, and then add a Cyclic Prefix (CP) to the head of each symbol to reduce the influence of adjacent symbol interference. The advantages of OFDM systems are high spectrum efficiency, longer symbol duration against intersymbols interference (ISI) effect in multi-path environments, and narrow transmission band of each sub-carrier within coherence bandwidth such that the communication channel can be viewed as flat and not frequency selective. The project is intended to design and implementation of OFDM System, which includes key blocks such as Viterbi Encoder/Decoder, IFFT/FFT, A/D, D/A, Parallel to Serial Converter and Serial to parallel Converter. The VHDL code can be simulated to verify its functionality. Then gate level design equivalent will be synthesized targeting FPGA device.