中文摘要：

提出了一类基于离散余弦变换（DCT）的正交频分复用（OFDM）-N重最小频移键控（NMSK）/N重正交最小频移键控系统（NQMSK）.该类系统将NMSK调制方式与基于DCT的OFDM多载波技术结合在一起,尽管系统频谱利用率有所降低,但却有效改善了系统带外衰减并减弱载波频率偏移所引起的性能恶化.理论分析和仿真结果表明,无论是在加性高斯白噪信道下还是在瑞利衰落信道下,考虑到载波频率偏移等因素的影响,该类系统都展示了其优越性能.

英文摘要：

One type of orthogonal frequency division multiplexing（OFDM）-N minimum-shift keying（NMSK）N quadrature MSK（NQMSK）system based on discrete cosine transform（DCT）is proposed.By combining the NMSK modulation scheme with the OFDM technology based on DCT,although the frequency efficiency is reduced to some extend,it can improve the out-of-band attenuation greatly and the performance deterioration caused by carrier frequency offset（CFO）will be mitigated.In the presence of CFO,analysis and simulation results show the excellent performance of the OFDM-NMSKNQMSK system based on DCT over both additive white Gaussian noise（AWGN）and Rayleigh fading channels.