Precoded and vector OFDM robust to channel spectral nulls and with reduced cyclic prefix length in single transmit antenna systems
Precoded and vector OFDM robust to channel spectral nulls and with reduced cyclic prefix length in single transmit antenna systems
复制标题
DOI：
10.1109/26.939855
复制
发表时间：
2001-08
期刊：
影响因子：
--
通讯作者：
X. Xia
中科院分区：
文献类型：
--
作者：
X. Xia
当符号间干扰（ISI）信道具有频谱零点时，正交频分复用（OFDM）系统的性能可能会下降。此外，当ISI信道具有许多抽头时，由于循环前缀的插入而导致的数据速率开销很高。首先，我们提出了一种预编码的OFDM系统，可以提高OFDM系统的频谱空信道的性能。我们还提出了大小K/spl倍/x1矢量OFDM（VOFDM）系统，减少了K倍的循环前缀长度相比，传统的OFDM系统。预编码方案只是在每两组K个连续信息符号之间插入一个或多个零，尽管它可以被推广到一般形式。该预编码方案能够在不知道ISI信道的情况下去除ISI信道的频谱零点。当在每两组K个连续的信息符号之间不插入零，并且只有每K个连续的符号被分块在一起时，我们得到VOFDM系统。理论性能分析和仿真结果。最后，我们比较了VOFDM系统和酉矩阵调制的组合与传统的OFDM系统和相移键控调制，其中差分（非相干）和相干调制和解调都被认为是。
The performance of orthogonal frequency-division multiplexing (OFDM) systems may be degraded when intersymbol interference (ISI) channels have spectral nulls. Also, when ISI channels have many taps, the data rate overhead due to the insertion of the cyclic prefix is high. We first propose a precoded OFDM system that may improve the performance of the OFDM systems for spectral null channels. We also propose size K/spl times/x1 vector OFDM (VOFDM) systems that reduce the cyclic prefix length by K times compared to the conventional OFDM systems. The precoding scheme is simply to insert one or more zeros between each two sets of K consecutive information symbols, although it can be generalized to a general form. This precoding scheme may be able to remove the spectral nulls of an ISI channel without knowing the ISI channel. When no zero is inserted between each two sets of K consecutive information symbols and only each K consecutive symbols are blocked together, we obtain VOFDM systems. Both theoretical performance analysis and simulation results are presented. Finally, we compare the combination of the VOFDM systems and the unitary matrix modulation with the conventional OFDM systems and the phase-shift keying modulation, where both differential (noncoherent) and coherent modulations and demodulations are considered.