I Introduction
Orthogonal Frequency-Division Multiplexing (OFDM) has recently attracted considerable attention since it has been shown to be an effective technique to combat delay spread or frequency selective fading of wireless or wireline channels. This approach has been adopted as the standards in several outdoor and indoor high-speed wireless and wireline data applications, including Wireless Local Area Networks (WLAN), Digital Audio and Video Broadcasting (DAB and DVB), and Digital Subscriber Line (DSL) modems [1]. OFDM transmission requires no equalizers, which makes it possible to combine with many advanced techniques to improve the capacity and enhance the performance of transmission.