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This paper is devoted to evaluating the combined coherent and incoherent sources (CCIS) technique for different applications in the optical domain and future optical code division multiple access (OCDMA) networks. Spectral amplitude coding (SAC) has gained significant attention in optical processing systems due to its increased capabilities in dealing with multiple-access interference (MAI) efficiently. Fixed right shift (FRS) is adopted as a signature code in this study. Furthermore, performance analysis is studied in terms of bit error rate (BER) for the system using CCIS in both the free space optics (FSO) and sky mesh network using an aerial altitude platform system (AAPS). Simulation results confirmed that a CCIS design significantly improves system performance with moderate cost. An acceptable BER value of 10 − 9 at 1.25 Gbps data rate and 60 km, 38 km, and 6 km distances for the laser, CCIS, and LED sources, respectively, can be supported. In particular, at Q-factor ~4.5, the FSO ranges under low haze, moderate haze, and heavy haze are, respectively, 3.7 km, 2.5 km, and 1.5 km. The reason is that a CCIS design causes an increase in the effective transmitted power. It can be summarized that a CCIS design can provide reliable solutions and an affordable cost for future optical fiber and wireless network applications. [ABSTRACT FROM AUTHOR]

Code classification is essential nowadays, as determining the transmission code at the receiver side is a challenge. A novel algorithm for fixed right shift (FRS) code may be employed in embedded next-generation optical fiber communication (OFC) systems. The code aims to provide various quality of services (QoS): audio, video, and data. The Q-factor, bit error rate (BER), and signal-to-noise ratio (SNR) are studied to be used as predictors for machine learning (ML) and used in the design of an embedded QoS classifier. The hypothesis test is used to prove the ML input data robustness. Pearson's correlation and variance-inflation factor (VIF) are revealed, as they are typical detectors of a data multicollinearity problem. The hypothesis testing shows that the statistical properties for the samples of Q-factor, BER, and SNR are similar to the population dataset, with p-values of 0.98, 0.99, and 0.97, respectively. Pearson's correlation matrix shows a highly positive correlation between Q-factor and SNR, with 0.9. The highest VIF value is 4.5, resulting in the Q-factor. In the end, the ML evaluation shows promising results as the decision tree (DT) and the random forest (RF) classifiers achieve 94% and 99% accuracy, respectively. Each case's receiver operating characteristic (ROC) curves are revealed, showing that the RF outperforms the DT classification performance. [ABSTRACT FROM AUTHOR]

One dimensional encoding in optical communications has limitations in terms of the number of supported users and large bandwidth consumption. This study presents a new algorithm to generate two-dimensional (2D) encoding utilizing permutation vectors (PV) theory for incoherent multiple access network to suppress multiple access interference (MAI) and system complexity. The proposed code design approach is based on spectral/spatial techniques for code generation. All possible combinations of PV code-sets are obtained by utilizing all permutations of the vectors with the repetition of each vector weight (W) times. Furthermore, the 2D-PV code-set is constructed by combining two code sequences of the 1D-PV code. Furthermore, the transmitter–receiver architecture of the 2D-PV spectral/spatial (S/S) code based OCDMA system is presented. The Gaussian approximation is used to analyze the performance of the proposed OCDMA system with 2D- PV code by considering various noise sources (shot, thermal, and PIIN). Results indicate that the 2D-PV code provides increased cardinality by eliminating phase induced intensity noise (PIIN) effects with a minimum likelihood of interference between multiple user data. Simulation implementations validate the proposed system performance for an agreeable bit error rate (BER) of 10–9 [ABSTRACT FROM AUTHOR]

• Development of new SSM families. • A configurable transmitter–receiver structure using S S M SSM code to support QoS. • High and Low QoS diversity are offered based on user choices. • Accommodation of large number of active users with high bit rate. This paper proposes a new coding scheme for spectral amplitude coding (SAC) family, known as Sigma Shift Matrix (SSM). Two techniques are proposed for the design of SSM coding scheme. The first technique combines the identity and upper shift matrices to form an SSM coding matrix named as SSM I. The second approach adapts the assembly of a single – entry, lower and upper shift matrices to compose another SSM matrix called SSM s. Combination of these matrices generates variable SSM code families, which can provide more flexibility in code weight selection and the number of users respectively. Furthermore, a modified SSM (MSSM) coding scheme is proposed through bitwise ANDing of SSM I and SSM S to further elevate performance of the proposed setup. The optimized structure of SSM coding scheme eliminates the influence of multiple access interference (MAI) and alleviate the effect of phase induced intensity noise (PIIN). Numerical results show that MSSM, SSM I and S S M S SSM S outperform the existing coding schemes in descending order and proves to be an efficient candidate for the implementation of high capacity next generation of optical communication networks. [ABSTRACT FROM AUTHOR]

Merging two coherent and incoherent optical sources: continuous wave light amplification by stimulated emission of radiations (CW LASER) and light emitting diode (LED) despite the difference in their physical nature from each other could be an efficient approach to expand a highly occupied network while trading-off the cost. In this paper, an efficient SAC-OCDMA system based on coherent and incoherent optical sources (CCIS) is designed. To evaluate CCIS design, fixed right shifting (FRS) code is adopted. FRS is built by utilizing specific type of Jordan matrices with direct algebraic procedures with minimum cross correlation (MCC). Additionally, an MCC elimination process would be more efficiency and can be seen in supporting large number of users. A quantitative comparison between SAC-OCDMA system using LED, CW laser sources and CCIS design is presented. Compared to LED sources, a CCIS design increases the number of supported users by almost three time while a reduction in number of optical sources is obtained by ≈ 50%. As compared to CW Laser sources, a CCIS design shows a reduction in number of optical sources by almost 50% while a lessening in number of supported users by ≈ 21%. A 22.6% cost saving per user is achieved for CCIS design over CW laser for nearly similar performance. It concludes that, CCIS design can provide a good solution for optical communication system. [ABSTRACT FROM AUTHOR]