Blind Adaptive Multiuser Detection for Chaos CDMA Communication

Abstract

Abstract-Chaos-based CDMA communication has opened up a new category for spread spectrum communication, where the spreading code that is used to scramble data in the CDMA systems can be generated using a single mathematical relationship of a chaotic generator instead of using the pseudo-noise (PN) generator. Recent studies showed that this sequence can enhance the security and increase the capacity of the system at the physical link due to its bifurcation behavior. In this paper, we investigate the performance of multiuser detection schemes in chaos based and PN code-division multiple access (CDMA) systems. Two wellknown schemes are applied and compared: adaptive filtering using the constant modulus algorithm (CMA) and matched filtering (using a correlator). Simulation results showed that, for both schemes, the chaos-based CDMA outperforms the PN-based CDMA in terms of bit error rate (BER) and mean-squared error (MSE).

Efficient Secure NOMA Schemes Based on Chaotic Physical Layer Security for Wireless Networks

“…In the literature, numerous CBSC schemes have been investigated for the CD/PD-NOMA by exploiting the aforementioned characteristics of chaotic signals [5], [24]- [26], [33]- [39]. In [38] and [39], non-orthogonal CDMA schemes with PLS have been designed based on chaotic spreading codes rather than the conventional pseudo-noise sequences.…”

Multi-level Chaos-Shift-Keying for Non-Orthogonal Multiple Access with Physical Layer Security

“…Moreover, the parameters of the chaotic system can provide an enormous key-space that remarkably enhances the system security against eavesdroppers bruteforce attacks [14]. For example, various CBSC systems based on NOMA approaches have been studied such as [9], [16] over Gaussian channels and [6], [12], [17] over fading channels with multiple-input multiple-output (MIMO) technique integrated with orthogonal frequency division multiplexing (OFDM) method [11].…”

“…The realized security gap based on the performance of bit-error-rate (BER) emerges as an efficient and practical PLS measure to evaluate the achieved PLS instead of the information theoretic-based measures such as the secrecy throughput, secrecy outage probability, and secrecy rate [3], [9]- [14], [18]. Secure communications may be achieved by expanding the realized gap between the BER performance of legal and illegitimate receivers [17]- [20]. Other important metrics are considered also like the key-space which is employed to assess the computational efforts required by an external eavesdropper to guess the secret keys correctly.…”

“…The major contributions for this paper may be highlighted as follows: 1) A generalized uplink multiuser communications system design of secure CD-NOMA (SCD-NOMA) is presented over the environment of a realistic channel. Composite largescale propagation and small-scale Rician fading are adopted rather than the simple Gaussian channel in [9] and [16] or the small-scale Rayleigh fading in [3], [12], and [17]. 2) Multi-level chaos-shift-keying (MCSK) modulators and demodulators are used at the communication ends rather than the binary CSK in [3], [12], [16], and [17] to create an effective PLS with a large key-space advantage and higher spectral efficiency.…”

“…Composite largescale propagation and small-scale Rician fading are adopted rather than the simple Gaussian channel in [9] and [16] or the small-scale Rayleigh fading in [3], [12], and [17]. 2) Multi-level chaos-shift-keying (MCSK) modulators and demodulators are used at the communication ends rather than the binary CSK in [3], [12], [16], and [17] to create an effective PLS with a large key-space advantage and higher spectral efficiency. At the receiving base station (BS), maximum likelihood (ML) and chaotic demodulation are used together for multiuser detection (MUD).…”