CHAPTER Equalization of Time-Varying Channels 1 The 6 Philip Schniter 1 , Sung-Jun Hwang 2 , Sibasish Das 3 , Arun P. Kannu 4 Ohio State University, Columbus, OH, USA 2 Qualcomm, Inc., Santa Clara, CA, USA 3 Qualcomm, Inc., San Diego, CA, USA 4 Indian Institute of Technology, Madras, Chennai, India 6.1 INTRODUCTION As discussed in Chapter 1, the wireless communication channel can be modeled as a time-varying (TV) linear 1 system whose output is corrupted by additive noise. To reliably recover the transmitted information from the channel output, the receiver must address the effects of both linear distortion and additive noise. Although, in theory, the mitigation of linear distortion and additive noise should be