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

Abstract

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.

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

“…Based on this principle, a successive scheme using multiple hill‐climbing and subspace deflation techniques is proposed for PN sequence estimation. The proposed scheme in Liang et al has a better performance compared with the suggested algorithm in Qiu et al The proposed methods in previous studies do not consider multipath effect and are used only in the AWGN channel. In Sidoropoulos et al, tensor‐based technique that uses the PARAFAC (parallel factor) to estimate the data of the users in the multiuser quasi‐synchronous DS‐CDMA system is presented.…”

“…In Haghighat and Soleymani, 26 a method in order to estimate the spectral spreading sequence of the users for synchronized DS-CDMA signals based on the MUSIC (Multiple Signal Classification) algorithm is presented. By combining the scheme presented in Haghighat and Soleymani 26 and the original idea behind the single-user-oriented segmentation-based algorithm in Pengyu et al, 19 an improved method is proposed in Qiu et al 27 in order to blind estimate the multiuser spreading sequence of the DS-CDMA signals. In Liang et al, 28 the problem of PN sequence estimation in asynchronous multiuser LS-DS-CDMA system is considered.…”

A Charrelation Matrix-Based Blind Adaptive Detector for DS-CDMA Systems

“…The problem of blind separation in DS-CDMA systems has attracted extensive attention for the past few years [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Research works related to blind separation for DS-CDMA systems are of particular interest in fields such as anti-jamming in military communications (MILCOM) and satellite communications (SATCOM).…”

Blind Estimation of PN Codes in Multi-user LSC-DSSS Signals

“…In reference [8], the Viterbi algorithm is used to search the possible pseudo random codes satisfying the maximum likelihood. The reference [9] proposed blind multiuser spreading sequences estimation algorithm for the LC-DS-CDMA signals, which divides the spreading sequences into multiple short-time windows. However, the criterion of determining the segmentation length is not considered.…”

“…However, the criterion of determining the segmentation length is not considered. On the basis of the work of reference [9], the segmentation length criterion is proposed, which is suitable for both LC-DSSS signals and LC-DS-CDMA signals [10].…”