Cyclic code shift keying: A low probability of intercept communication technique
Cyclic code shift keying: A low probability of intercept communication technique
复制标题
DOI：
10.1109/taes.2003.1238736
复制
发表时间：
2003-07-01
影响因子：
4.4
通讯作者：
Zeidler, B
中科院分区：
文献类型：
--
作者：
Dillard, GM;Reuter, M;Zeidler, B
描述了一种称为循环码移位键控(CCSK)的低截获概率(LPI)或低检测概率(LPD)通信技术。我们讨论了CCSK的基本概念，并描述了一种基于使用随机或伪随机码进行双相调制的系统。仿真结果表明，利用已有的适用于多进制正交信令(MOS)的公式，可以很好地估计CCSK的误码率。此外，我们还表明，当每个符号的比特数相同时，CCSK所需的计算量明显少于MOS。我们表明，使用双相调制产生的波形具有大的时间带宽积和非常低的输入信噪比(SNR)，因此固有地具有辐射计的LPI。我们评估了由辐射计进行的检测，并表明LPI可以通过使用长度大于约2(12)的码(即，通过每符号传输大于约12比特)来实现。结果表明，CCSK符号长度和错误概率、辐射计积分时间和虚警概率(PEA)对辐射计检测的影响。我们描述了CCSK的一种变体，称为截断CCSK(TCCSK)。在该系统中，长度为2(K)的代码被循环移位，然后被截断并发送。虽然被缩短，但被截断的代码仍然表示k比特的信息，从而导致数据速率的增加。我们对TCCSK的辐射计检测进行了评估，结果表明，与CCSK相比，TCCSK的检测概率有所增加。
A low probability of intercept (LPI), or low probability of detection (LPD) communication technique known as cyclic code shift keying (CCSK) is described. We discuss the basic concepts of CCSK and describe a system based on the use of random or pseudorandom codes for biphase modulation. We use simulation to show that the bit error rate (BER) for CCSK can be closely estimated by using existing equations that apply to M-ary orthogonal signaling (MOS). Also, we show that significantly fewer computations are required for CCSK than for MOS when the number of bits per symbol is the same. We show that using biphase modulation results in waveforms that have a large time-bandwidth product and very low input signal-to-noise ratio (SNR) and thus inherently have an LPI by a radiometer. We evaluate detection by a radiometer and show that LPI can be achieved by using codes of lengths greater than about 2(12) (i.e., by transmitting more than about 12 bits per symbol). Results illustrate the effect that the CCSK symbol length and error probability, and the radiometer integration time and probability of false alarm (PEA), have on detection by a radiometer. We describe a variation of CCSK called truncated CCSK (TCCSK). In this system, the code of length 2(k) is cyclically shifted, then truncated and transmitted. Although shortened, the truncated code still represents k bits of information, thus leading to an increased data rate. We evaluate radiometer detection of TCCSK and it is shown that the probability of detection is increased compared with the detection of CCSK.