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arXiv 1111.0547astro-ph.IMcs.ITmath.ITphysics.pop-ph
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星际通信:扩频的情况

Interstellar Communication: The Case for Spread Spectrum

David G. Messerschmitt

摘要:

在现代数字无线地面无线电系统中广泛使用的扩频选择具有类噪声特性和比所需带宽高得多的带宽的信号。本文主张扩频调制星际通信,出于强大的免疫力,在接收器附近的技术起源的射频干扰(RFI),同时保留在存在自然噪声源的充分检测灵敏度。接收机抗扰度设计本身不提供选择具有任何特定特征的信号的基础,因此无法减少模糊性。通过将RFI作为设计目标添加到抗噪性,信号的选择(由发射机)与抗噪性的最佳检测(在接收机中)的结合通过简单的概率论证导致信号应该具有白噪声突发的统计特性并且还具有大的时间带宽积的结论。因此,通过减少关于信号特征的模糊性,扩频还提供了发射机和接收机之间的隐含协调。该策略要求接收机猜测特定的类噪声信号,并且有人认为,如果在算法上生成适当的伪随机信号,则这是可行的。例如,概念上简单的算法,如二进制扩展的共同无理数,如Pi被证明是合适的。由于其有意加宽的带宽,扩频在通过星际介质的传播中更容易受到色散和失真的影响,期望减少带宽和载波频率等参数的模糊性。这表明了利用扩频调制技术进行星际通信的一个有希望的新方向。

英文摘要:

Spread spectrum, widely employed in modern digital wireless terrestrial radio systems, chooses a signal with a noise-like character and much higher bandwidth than necessary. This paper advocates spread spectrum modulation for interstellar communication, motivated by robust immunity to radio-frequency interference (RFI) of technological origin in the vicinity of the receiver while preserving full detection sensitivity in the presence of natural sources of noise. Receiver design for noise immunity alone provides no basis for choosing a signal with any specific character, therefore failing to reduce ambiguity. By adding RFI to noise immunity as a design objective, the conjunction of choice of signal (by the transmitter) together with optimum detection for noise immunity (in the receiver) leads through simple probabilistic argument to the conclusion that the signal should possess the statistical properties of a burst of white noise, and also have a large time-bandwidth product. Thus spread spectrum also provides an implicit coordination between transmitter and receiver by reducing the ambiguity as to the signal character. This strategy requires the receiver to guess the specific noise-like signal, and it is contended that this is feasible if an appropriate pseudorandom signal is generated algorithmically. For example, conceptually simple algorithms like the binary expansion of common irrational numbers like Pi are shown to be suitable. Due to its deliberately wider bandwidth, spread spectrum is more susceptible to dispersion and distortion in propagation through the interstellar medium, desirably reducing ambiguity in parameters like bandwidth and carrier frequency. This suggests a promising new direction in interstellar communication using spread spectrum modulation techniques.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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