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| An Identification Method of Long Pseudo-random Code Sequence in Non-periodic Direct Sequence Spread Spectral Signals |
| Zhao Zhi-jin Gu Xiao-wei Shen Lei |
| School of Communication Engineering, Hangzhou Dianzi Univeristy, Hangzhou 310018, China |
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Abstract Using the second-order and third-order autocorrelation characteristics of m sequences, the maximum likehood estimation for the triple autocorrelation function of the Non-Periodic Long Code Direct Sequence Spread Spectral (NPLCDS-SS) signals is deduced. By utilizing the shift-and-add property and the triple autocorrelation characteristics of m sequences, the influence of the information code on the estimation is eliminated by the processing of delay and multiplication, a identification method for long code is proposed based on the peaks of the triple autocorrelation function in a non-cooperative communication with the certain carrier frequency and chip width of spreading code. Simulations under additive white Gaussian noise show that the correct identification probability of the algorithm is above 90% when a quarter of the cycle length of the long PN code signal is used only and the signal-to-noise ratio is greater than 3.5 dB.
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Received: 24 September 2013
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Corresponding Authors:
Gu Xiao-wei
E-mail: johnsongutc@126.com
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2014, Vol. 36 
