Joint Carrier Frequency Offset and Channel Estimation for OFDM Based Gigabit Wireless Communication System with Low Precision ADC

Orthogonal Frequency Division Multiplexing (OFDM) technique serves as an important architecture for very high data rate short range wireless communication systems from Ultra-Wideband (UWB) to 60GHz millimeter wave systems for Wireless Personal Area Networks (WPANs). One of the bottleneck in implementing these high data rate systems is the demanding requirement for high-speed and high-precision Analog-to-Digital Converters (ADCs), as these ADCs are either not available yet, or are very costly and power hungry. This motivates the hardware implementation to use lower precision ADC to simplify the implementation complexity. However, using lower precision ADC will degrade the entire system performance significantly from frequency offset and channel estimation to demodulation and decoding. In this paper, we address the important problem at the front end of an OFDM system, i.e., Carrier Frequency Offset (CFO) and channel estimation problem when using lower precision ADC. We propose joint CFO and channel estimation algorithm using low precision ADC with feedback dither control. Our simulation result shows that it is possible to approach the CFO and channel estimation performance with full precision ADC by using low precision ADC with feedback dither control.