级联低密度校验码的差分酉空频调制技术

提出了一种新的级联低密度校验码的“差分酉空频调制”方案,该方案适用于收发端均未知信道状态信息的多输入多输出(OFDM)系统.“差分酉空频调制”是在发送天线与OFDM子载波之间进行“空频”编码,而在相邻两个OFDM码字之间进行差分调制,它可以充分利用多径衰落信道所提供的频率分集资源,不需要任何信道状态信息就能够获得最大的频率分集增益.由于其具有最大化的频率分集增益和较高的编码增益,故该方案的系统误码率性能远远优于新近研究文献中所提出的“差分酉空时调制”OFDM技术.在接收端提出了非相干迭代译码方案,其性能良好,同时译码复杂度相对较低.相应的仿真研究表明,该方案在“时频双选”信道下具有很强的鲁棒性.

Low-Density Parity-Check Based Differential Unitary Space-Frequency Modulation for MIMO-OFDM Systems

This paper proposed a novel differential unitary space-frequency modulation(DUSFM) scheme concatenated with LDPC codes for MIMO-OFDM systems when neither the transmitter nor the receiver has access to the channel state information(CSI).The new DUSFM strategy consists of coding across transmit antennas and OFDM tones simultaneously as well as differential modulation between two adjacent OFDM blocks.It can fully exploit the inherent advantages provided by the multipath fading channels,resulting in a high degree of diversity.The state-of-the-art low-density parity-check(LDPC) codes are concatenated with the DUSFM as channel coding to improve the bit error rate(BER) performance considerably.Owing to the maximum multipath diversity and large coding advantages,LDPC-DUSFM strongly outperforms the DUSTM recently proposed in literature.The low-complexity non-coherent iterative decoding algorithm is finally provided to offer significant performance gain.The simulation results illustrate the merits of the proposed scheme.