Novel approach to shape the spectrum for TDS-OFDM systems with cancellation carriers

Time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) outperforms the classical cyclic prefix OFDM (CP-OFDM) in higher spectral efficiency and faster synchronization. However, TDS-OFDM suffers from severe out-of-band power emission since the OFDM data block and the guard interval are two independent time-domain signals. Hence, squared root raised cosine (SRRC) filters have to be adopted in TDS-OFDM broadcasting system to perform the spectrum shaping. Unfortunately, SRRC filters may introduce higher complexity in the hardware implementation, limiting its applications in many situations. In this paper, a novel approach based on cancellation carriers and time-domain windowing is proposed to shape the spectrum for TDS-OFDM systems. Simulations show that the proposed method could reduce the out-of-band power emission significantly without increasing the system complexity.