ABSTRACT
This chapter is intended to relate recent advances in the field of time-frequency signal processing (TFSP) to the need for further capacity of wireless communications systems. It first presents, in a brief and heuristic approach, the fundamentals of TFSP. It then describes the TFSP-based methodologies that are used in wireless communications with special emphasis on spread-spectrum techniques and time-frequency array processing. Topics discussed include channel modeling and identification, estimation of scattering function, interference mitigation, direction of arrival estimation, time-frequency MUSIC, and time-frequency source separation. Finally, other emerging applications of TFSP to wireless communications are discussed.
Wireless communications is growing at an explosive rate, stimulated by a host of important emerging applications ranging from third-generation mobile telephony, wireless personal communications, and wireless subscriber loops, to radio and infrared indoor communications, nomadic computing, and wireless tactical military communications. Signal processing has played a key role in providing solutions to key problems encountered in communications in general, and in wireless communications in particular [1]. An important branch of signal processing called time-frequency signal processing (TFSP) has emerged over the past decades [2, 3]. It provides effective tools for analyzing nonstationary signals where the frequency content of signals varies in time, as well as for analyzing linear time-varying systems. The purpose of this chapter is to review the methodologies of TFSP applied to wireless communications.
