OFDM is a multi-carrier system where data bits are encoded to multiple sub-carriers and sent simultaneously in time. The result is an optimum usage of bandwidth. A set of orthogonal sub-carriers together forms an OFDM symbol. To avoid ISI due to multi-path, successive OFDM symbols are separated by guard band. This makes the OFDM system resistant to multi-path effects. Although OFDM in theory has been in existence for a long time, recent developments in DSP and VLSI technologies have made it a feasible option.
This paper describes the VLSI implementation of OFDM in details. Specifically the 802.11a OFDM system has been considered in this paper. However, the same considerations would be helpful in implementing any OFDM system in VLSI.OFDM is fast gaining popularity in broadband standards and high-speed wireless LAN.
OFDM is a multi-carrier system where data bits are encoded to multiple sub-carriers. Unlike single carrier systems, all the frequencies are sent simultaneously in time. OFDM offers several advantages over single carrier system like better multi-path effect immunity, simpler channel equalization and relaxed timing acquisition constraints. But it is more susceptible to local frequency offset and radio front-end non-linearities.