M-ary spread spectrum ofdm structure based on cascaded cyclic shift complementary pairs

Based on the cascade of cyclic shift versions of complementary pairs, a new set of mutually orthogonal sequence pairs with the center element of each sequence equal to zero is constructed. Compared with traditional complementary sequences, the constructed mutually orthogonal sequence pairs will be more suitable for orthogonal frequency division multiplexing (OFDM) systems when the zero element in sequence center is modulated to direct current subcarrier. By combining ideal aperiodic correlation properties with zero center element characteristic, we design a new kind of M-ary spread spectrum OFDM (MSS-OFDM) structure. Different from the previous researches on MSS-OFDM systems, the designed MSS-OFDM structure not only possesses high bandwidth efficiency and low realization complexity, but also can effectively resist the peak-to-average power ratio near to 3dB.