Study On Channel Estimation And Equalization Technique For OFDM Based Wireless Broadband Mobile Commnication Systems

Orthogonal Frequency Division Multiplexing (OFDM) is one of the most promising techniques for wireless broadband mobile communication. The channel property of frequency selective fading and Doppler frequency shift are the biggest challenge to the broadband mobile communication service. By employing cyclic prefix, OFDM can effectively eliminate the disturbance from inter-symbol interference introduced by multi-path channel. Besides, OFDM can combat the time selective fading, with flexibly designed frame structure according to channel property. Thanks to the FFT algorithm, OFDM avoids complex adaptive filter based time domain equalizer, and can provide robust communication quality with relatively simple implementation complexity. OFDM has been widely adopted in existing wireless communication standards.Accurate channel state information is needed in OFDM systems to perform channel equalization and compensate the multi-path fading. Channel estimation is consequently critical to the whole system performance. In this dissertation, we will discuss channel estimation and equalization technique under wireless mobile channel, according to different types of OFDM systems. We will provide detailed analyzes of these channel estimation and equalization issues.First, we discuss the classical channel estimation techniques based on frequency domain inserted pilot, and corresponding frequency domain equalization. We classify these existing channel estimation algorithms into two categories: frequency domain processing methods and time domain processing methods, and make detailed analysis and comparison between them. Besides, we discuss various interpolation and channel tracking algorithms which are widely used...