VHDL Implementation of FFT/IFFT Blocks for OFDM

In many applications high-speed performance is required. For this purpose, conventional multi-carrier techniques are usually chosen, but this results in the lowering of spectrum efficiency. So, the principles of orthogonal frequency division multiplexing are used in such applications. This paper gives the details of the development of IFFT & FFT algorithms to be used in OFDM systems based on the IEEE 802.11a standard for WLAN. This system consists of separate OFDM transmitter & receiver. Actually, in the entire architecture of OFDM system, all the mathematical manipulations take place in these two blocks only, i.e. IFFT & FFT blocks while rest of the blocks convert the data from one format to another format. In this paper we have implemented FFT and IFFT blocks in VHDL. The speed enhancement is the key contribution of the main processing blocks in OFDM system.