A Subband Approach to Channel Estimation and Equalization for DMT and OFDM Systems

Abstract

Cyclic prefix (CP) is commonly used for channel equalization of discrete multitone (DMT) and orthogonal frequency-division multiplexing (OFDM) systems. This is often done in conjunction with a time-domain equalizer (TEQ) for reducing the capacity overhead caused by the CP. However, the use of TEQ greatly increases the computational cost, and is unable to eliminate the need for the CP. In this paper, we propose a subband approach to channel estimation and channel equalization for DMT and OFDM systems. This approach involves splitting the received signals into a number of frequency bands (called subbands), and estimating a constant parameter in each subband. The subband approach is conceptually simple, requires no CP, is much more numerically efficient than the TEQ method, and gives compatible or better estimation errors than the CP-based methods.