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Beamforming combined with massive multiple-input multiple-output (MIMO) antenna arrays are expected to be the most important aspects of 5G and beyond wireless networks. In this paper, an 8 × 8 massive MIMO array with beamforming is proposed for 5G and beyond wireless applications. To develop this design, the substrate of polyimide material is used having a 3.5 dielectric constant and a thickness of 0.03 mm. The proposed massive MIMO antenna array resonates at two distinct frequencies i.e. 0.8195 and 1.4675 THz with a return loss of less than − 10 dB. Performance parameters like return loss, antenna gain, directivity, bandwidth, radiation pattern and VSWR are observed. With its greater directional gain of 25.6 dB and better directivity of 25.617 dB, the proposed 8 × 8 massive MIMO has a wider bandwidth of 66.7 GHz. In addition, the proposed array's radiation efficiency is 96%, its diversity gain is 9.9999 dB, its ECC is almost zero, its CCL is less than 25 bps/Hz, its TARC is less than − 10 dB, and its CC < 0.4 bps/Hz. The results gathered demonstrate that the proposed massive MIMO antenna array can be employed successfully for a wide range of terahertz applications due to its enhanced characteristics. [ABSTRACT FROM AUTHOR]

In this paper, a novel architecture of bidirectional underwater wireless optical communication (UWOC) system has been proposed to interconnect stationary and moving underwater sensor nodes for diverse applications. To achieve the bidirectional communication, wavelength division multiplexing (WDM) and remodulation approach have been used in this work. The proposed bidirectional UWOC system works at 40 Gbps data rate for both downlink (stationary node to moving node) and uplink (moving node to stationary node). Two distinct wavelengths of 532 nm and 531 nm have been used for uplink and downlink, the main attraction of the proposed architecture is that both the laser sources are placed at the stationary node. The moving node do not have any laser source and it remodulates the signal for sending data back to the stationary node. Because of this, the moving node contains lesser components which results in cost effectiveness, low power requirement and light weight. The proposed system successfully transmits the bidirectional information at a link range of 40 m under pure sea conditions in the presence of distinctive air bubble populations. The observed bit error rate (BER) values are 1.89 × 10− 13 and 1.19 × 10− 04 for the downlink and uplink respectively at a link range of 40 m, these BER values are under the acceptable forward error correction (FEC = 2 × 10− 3) limit. The proposed bidirectional UWOC system is beneficial for the development of a high-speed last-mile underwater solution. [ABSTRACT FROM AUTHOR]

Ranging from optical fiber communication to optical wireless communication regimes, twisted light has drawn the prodigious contemplation of researchers. Thus far, the tricolor visible light laser diodes (TVL-LDs) have not been scrutinized for optical angular momentum (OAM), which, however, could pioneer fortuitousness towards a new paradigm of indoor wireless communication. Here, we proposed an OAM superposition of three different Laguerre Gaussian modes such as l = 0, m = 0; l = 14, m = 0; and l = 40, m = 0, and realised by utilising red, green and blue (R/G/B) LDs as independent channels and binary data streams are encoded incorporating non return to zero linecoding, exhibiting a total capacity of 45 Gbps (3 wavelengths (λ) × 3 OAM beams × 5 Gbps). The performance of R/G/B LDs is compared in a visible light communication (VLC) model at different input parameters such as link length between the irradiating source (Lambertian) and receiver detection region, transmitter half angle, incidence half angle, and optical concentrator area. We successfully performed the transmission of 45 Gbps data over a 1.4 m line of sight VLC link and 2.3 m in a non-LoS link employing TVL-LDs, while the red LDs offered excellent performance. [ABSTRACT FROM AUTHOR]

In this paper, the 50 Gbps next generation passive optical network stage 2 (50G- NGPON2) architecture is proposed via converging millimeter wave (MMWave) over fiber technology to meet the requirements of fifth generation (5G) fronthaul network such as enormous demand of high transmission rate and huge bandwidth. It uses the non-return to zero (NRZ) line code to generate pulse for 50 Gbps of data per channel, 28 GHz MMWave spectrum band over 60 km of bi-directional fiber span under the ITU-T G.9804 standardization. Two ideal erbium dopped fiber amplifiers (EDFA) with the gain of 10 dB and 5 dB respectively are used to amplify the signal on the transmitter side before transmission and receiver side after transmission. Outcomes of the proposed system demonstrate the network structure performance efficiency via Q-Factor (> 6), error rate, spectrums, and eye diagram. The variations of the Q-Factor for all optical network units (ONUs) during downstream and channels during upstream can be seen at the different fiber spans. Considering the scope of the future, in the area of digital processing, a single channel 50G-PON using 16-QAM is presented to improve the modulation and demodulation of MMWave spectrum. [ABSTRACT FROM AUTHOR]

The next generation passive optical network stage 2 (NG-PON2) is a broadcast network in which a large number of optical network units (ONUs) can be served using various network topologies. In this paper, a purely passive remote node (RN) design based on fiber bragg grating (FBG) is presented for the bus topology of a high split NG-PON2 system. The performance of the proposed node has been analysed for a symmetric 80 Gbps NG-PON2 system serving 1024 ONUs in terms of bit error rate (BER) and optical signal to noise ratio (OSNR). The working of the proposed node has been explained with the optical frequency spectrums for downstream and upstream signals. The observed OSNR levels for the ONUs operating at the 1st RN is 84.8743 dB which decreases to 75.7973 dB for the ONUs connected to the 8th RN. The BER level < 10–9 for both upstream and downstream confirms the correct working of the proposed node in the NG-PON2 system. [ABSTRACT FROM AUTHOR]

Security enhancement and bandwidth increase are requirements of ultrafast future optical code division networks that also minimise the latency at nodes without distressing the traffic performance. In OCDMA systems, eavesdropper tries to breach the optical code, and encoded/encrypted data in order to get correct code word of legitimate user. For security enhancement, an ultra high speed 4 × 100 Gbps two dimensional Diagonal identity matrix (2D-DIM) code and four input single output (FISO) all optical logic gate with private key encryption is proposed and its performance in terms of security is analyzed. Expressions for synchronous and asynchronous transmissions are derived for proposed work and it is perceived that asynchronous transmission has better security. Further performance/security analysis is carried out for different scenarios such as with/without FISO, with 1D-DIM/2D-DIM codes, using 4 × 1 AND gate/NOR gate in terms of correct code detection rate (CCDR), max. eye amplitude, Received Q factor, Signal to noise ratio at different launched power levels for legitimate user and eavesdropper. Eavesdropper attacked the proposed system but due to FISO layering, private key encryption, and 2D-DIM codes, cannot get acceptable level of CCDR. To the best of author's knowledge, proposed system is ultra high speed with enhanced security and no reported studies have investigated security enhancement at this much ultra high speed. [ABSTRACT FROM AUTHOR]