Shifted sequence padding TDS-OFDM modulation scheme
Time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) modulation scheme offers higher spectrum efficiency than that by cyclic prefix (CP) OFDM technique, but at the same time it increases computational complexity on the receiver side. And under time-varying channel conditions, residual inter-symbol-interference (ISI) due to imperfect channel estimation causes performance loss. Dual PN-sequence padding (DPNP) was later proposed to simplify equalization and to improve mobile reception at the cost of spectrum efficiency decrease. In this paper, an improved TDS-OFDM modulation scheme, shifted sequence padding (SSP), is proposed. Keeping low computational complexity provided by DPNP, it increases spectrum efficiency up to 8%, and offers more flexibility for receivers to adjust channel estimation approach according to channel conditions and complexity requirements. And it could be extended to support flexible physical frame structure.