Improved differential detection of chip-level differentially encoded direct-sequence spread-spectrum signals
Improved differential detection of chip-level differentially encoded direct-sequence spread-spectrum signals
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DOI：
10.1109/7693.975451
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
G. Colavolpe;R. Raheli
中科院分区：
文献类型：
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作者：
G. Colavolpe;R. Raheli
在Cavallini等人的论文中（参见IEEE Trans. Commun.，Vol.45，p.456-63，Apr.1997），提出了用于直接序列扩频信号的码片级差分编码/检测以科普频率非选择性快衰落信道。结果表明，与加性白色高斯噪声信道不同，在时变衰落信道中，系统性能可以得到显著改善，特别是当扩频因子增加时。在本文中，非相干序列检测，最近提出的作者，是出发点的推导接收机的性能提高相对于标准差分检测。对多进制相移键控信号进行了理论分析，并通过计算机仿真验证了分析结果。考虑到一个较大的相位存储器，相对于差分检测占最小的性能优势，证明。特别是，相位记忆的量作为瑞利频率非选择性衰落信道的多普勒扩展的函数进行优化。在相位噪声的存在下的鲁棒性也通过计算机模拟研究。
In a paper by Cavallini et al. (see IEEE Trans. Commun., vol. 45, p.456-63, Apr. 1997), chip-level differential encoding/detection for direct-sequence spread-spectrum signals was proposed to cope with frequency-nonselective fast fading channels. It was shown that, unlike in the additive white Gaussian noise channel, in time-varying fading channels the system performance may be considerably improved, especially when the spreading factor is increased. In this paper, noncoherent sequence detection, recently proposed by the authors, is the starting point for the derivation of receivers with improved performance with respect to that of standard differential detection. For M-ary phase-shift keying signals, a theoretical analysis is performed and the results are confirmed by means of computer simulation. The performance advantage of taking into account a larger phase memory, with respect to the minimum accounted for by differential detection, is demonstrated. In particular, the amount of phase memory is optimized as a function of the Doppler spread for a Rayleigh frequency-nonselective fading channel. The robustness in the presence of phase noise is also investigated by means of computer simulation.