Eavesdropping in the synchronous CDMA channel: an EM-based approach

Yao, Yingwei; Poor, Vincent

doi:10.1109/78.934146

Cited by 28 publications

(7 citation statements)

References 18 publications

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“…Multiuser system is always one of the main purposes in the PN estimation. In Yingwei and Poor, an EM‐based algorithm for the PN sequence estimation is proposed. Since this algorithm needs to be synchronized, a synchronization method is presented in Yingwei and Poor .…”

Section: Introductionmentioning

confidence: 99%

“…In Yingwei and Poor, an EM‐based algorithm for the PN sequence estimation is proposed. Since this algorithm needs to be synchronized, a synchronization method is presented in Yingwei and Poor . In Shalvi and Weinstein and Moulines et al, the method introduced in Burel and Bouder and Bouder for the multiuser systems in the AWGN channels is extended.…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19] Also, a method for the PN sequence blind estimation of the DSSS signals with residual carrier is presented in Zhang et al 2 Multiuser system is always one of the main purposes in the PN estimation. In Yingwei and Poor, 21,22 an EM-based algorithm for the PN sequence estimation is proposed. Since this algorithm needs to be synchronized, a synchronization method is presented in Yingwei and Poor.…”

mentioning

confidence: 99%

“…Since this algorithm needs to be synchronized, a synchronization method is presented in Yingwei and Poor. 21,22 In Shalvi and Weinstein 23 and Moulines et al, 24 the method introduced in Burel and Bouder 17 and Bouder 18 for the multiuser systems in the AWGN channels is extended. In this method, before the estimation of the spectral spreading sequence for each user, the synchronization is needed.…”

mentioning

confidence: 99%

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PN sequence blind estimation in multiuser DS‐CDMA systems with multipath channels based on successive subspace scheme

Sarcheshmeh

Bizaki

Alizadeh

2018

Int J Communication

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Summary In this paper, we proposed a new method based on expanding subspace algorithm and finite alphabet characteristics, for blind estimation of the users' spreading sequences in the multiuser direct sequence code division multiple access system in the presence of the multipath channels. In the proposed scheme, we show that the estimation of the users' overall channels in the direct sequence code division multiple access system is equivalent to the impulse response estimation of the multi‐input multi‐output finite impulse response channels. Our proposed approach is based on the successive estimation of the columns of the equivalent multi‐input multi‐output finite impulse response channels from the lowest degree columns to the highest degree ones. Accordingly, each user's overall channel that is the convolution of the original multipath channel and the spreading sequence is estimated. Then we extract PN sequences from the overall channel using finite alphabet characteristics of the spreading sequence chips for each user. According to simulation results, our proposed scheme outperforms the conventional methods in that it does not require symbol synchronization and does not have channel constraints (for example, AWGN and single user system) in the multipath channels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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PN sequence blind estimation in multiuser DS‐CDMA systems with multipath channels based on successive subspace scheme

Sarcheshmeh

Bizaki

Alizadeh

2018

Int J Communication

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“…Besides, the pre-assumed structure of code generating mechanism confined the use of this method. For synchronous short-code multiuser systems, Yingwei and Poor [13,14] proposed an EM-based algorithm for estimating the spreading codes after synchronisation. They also presented a method for acquiring code synchronisation.…”

Section: Introductionmentioning

confidence: 99%

Blind multiuser spreading sequences estimation algorithm for the direct-sequence code division multiple access signals

Qiu

Huang

Wen-li

et al. 2010

IET Signal Process.

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By combining the multiple signal classification (MUSIC)-based algorithm, proposed by Haghighat and Soleymani, and the segmentation-based idea, a blind multiuser spreading sequences estimation algorithm for the direct-sequence code division multiple access (DS-CDMA) signals is presented in this study. The main idea of the proposed algorithm is to divide the spreading sequences into short-time segments so as to recover them in a sequential procedure. First, the received signal samples are divided into K collections of temporal windows. Each collection is corresponding to a group of short-time segments of the spreading sequences. Secondly, by performing a sub-segmentation-based estimation scheme on the first collection of temporal windows, the first short-time segments of all the users' spreading sequences are extracted. Finally, with the help of the segments acquired in advance, the remaining segments of the spreading sequences can be recovered chip-by-chip through K 2 1 subspace projection loops. This algorithm can be applied not only to the synchronous short-code (SC) DS-CDMA signals, but also to the long-code (LC) DS-CDMA signals in non-cooperative contexts, even with minus SNR. Simulations are presented to illustrate the performance of the proposed method. In addition, for the synchronous SC-DS-CDMA signals, the computational cost of the proposed algorithm is much lower than that of the MUSIC-based algorithm. Furthermore, a derivation for blind synchronisation of the synchronous SC-DS-CDMA signals is also presented.

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Steganalysis of SS Steganography: Hidden Data Identification and Extraction

Liu

2015

Circuits Syst Signal Process

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Eavesdropping in the synchronous CDMA channel: an EM-based approach

Cited by 28 publications

References 18 publications

PN sequence blind estimation in multiuser DS‐CDMA systems with multipath channels based on successive subspace scheme

PN sequence blind estimation in multiuser DS‐CDMA systems with multipath channels based on successive subspace scheme

Blind multiuser spreading sequences estimation algorithm for the direct-sequence code division multiple access signals

Steganalysis of SS Steganography: Hidden Data Identification and Extraction

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