Recently, connected vehicles (CV) are becoming a promising research area leading to the concept of CV as a Service (CVaaS). With the increase of connected vehicles and an exponential growth in the field of online cab booking services, new requirements such as secure, seamless and robust information exchange among vehicles of vehicular networks are emerging. In this context, the original concept of vehicular networks is being transformed into a new concept known as connected and autonomous vehicles. Autonomous vehicular use yields a better experience and helps in reducing congestion by allowing current information to be obtained by the vehicles instantly. However, malicious users in the internet of vehicles may mislead the whole communication where intruders may compromise smart devices with the purpose of executing a malicious ploy. In order to prevent these issues, a blockchain technique is considered the best technique that provides secrecy and protection to the control system in real time conditions. In this paper, the issue of security in smart sensors of connected vehicles that can be compromised by expert intruders is addressed by proposing a blockchain framework. This study has further identified and validated the proposed mechanism based on various security criteria, such as fake requests of the user, compromise of smart devices, probabilistic authentication scenarios and alteration in stored user’s ratings. The results have been analyzed against some existing approach and validated with improved simulated results that offer 79% success rate over the above-mentioned issues.

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This work presents an 18 element antenna system compatible with massive multiple input multiple output (MIMO)/Diversity fourth/fifth generation (4G/5G) smartphones. The antennas are designed at sub-6 GHz long term evolution (LTE) band and . A simple slot type antenna is considered as the radiating element, with open ended slots used for obtaining a compact design. These slots also act as decoupling elements to improve the isolation among different radiators. The proposed antenna elements are designed on a low-cost FR-4 substrate having dimension of 150mm × 80mm × 1.6mm, which can be typically used for 6-inch smartphones. The simulated and measured values of antenna gain are found to be greater than 5.3 dBi. Simulated and measured results of the proposed design show excellent impedance matching (reflection coefficient>20 dB), port isolation (>20 dB), total efficiency (>87%) and Envelope Correlation Coefficient (<0.01) over the operating frequency. MIMO antenna performance metrics are verified by calculating the ergodic channel capacity with Kronecker channel model.

A circular monopole antenna for ultra wideband (UWB) applications with triple band notches is proposed. The proposed antenna rejects worldwide interoperability for microwave access WiMAX band (3.3 GHz-3.8 GHz), wireless local area network WLAN band (5.15 GHz-5.825 GHz) and X-Band downlink satellite communication band (7.1 GHz-7.9 GHz). The antenna utilises mushroomtype and uniplanar Electromagnetic Band Gap (EBG) structures to achieve band-notched designs. The advantages of band-notched designs using EBG structures such as notch-frequency tuning, triple-notch antenna designs and stable radiation pattern are shown. The effect of variation of EBG structure parameters on which notched frequency depends is also investigated. Fabricated and measured results are in good agreement with simulated ones.

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A 10 element multiple input multi output (MIMO)/Diversity antenna system is considered to work in Sub-6 GHz frequency range. The proposed design can work in long term evolution (LTE) band 42(3.4-3.6 GHz), LTE band 43(3.6-3.8 GHz) and LTE band 46(5.15-5.925 GHz). The proposed design consists of 10 identical and highly isolated T-shaped slot antennas fed with T-shaped lines. All three bands have the return loss values (<-6 dB) and total antenna efficiency (>83%) in free space. The peak value of envelope correlation coefficient is 0.06 and the calculated value of ergodic channel capacity is found to be greater than 41bps/Hz in all the bands.The effect of hand grip as well as the presence of battery and LCD screen is investigated. Simulated results are validated via fabrication and measurement of the proposed design.

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Abstract-A MIMO/Diversity antenna with triple notch characteristics is proposed in this article. The proposed antenna has triple notches in the WiMAX band (3.3-3.6 GHz), WLAN band (5-6 GHz), and X-band satellite communication (7.2-8.4 GHz) band. Defected Ground Compact Electromagnetic Band Gap (DG-CEBG) is a design used to accomplish band notches. Defected ground planes are utilised so as to achieve compactness in conventional EBG structures. The proposed WiMAX band, WLAN band, and X-band satellite communication band DG-CEBG structures show a compactness of around 46%, 50%, and 48%, respectively, over a conventional EBG structure. In these structures, decoupling strips and a slotted ground plane are used to enhance the isolation between two closely spaced UWB monopoles. The individual monopoles are 90 • angularly separated with a stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing the current path length. |S 21 | or mutual coupling is found to be less than 15 dB over the whole UWB frequency range. The Envelope Correlation Coefficient (≤ 0.5) is within the acceptable limits over the whole UWB frequency range. Notched frequency depends on the parameters of DG-CEBG structures; when there is a change in these parameters notch frequency is also changed. A low cost FR-4 substrate with thickness (h) = 1.6 mm, permittivity (ε) = 4.4 and loss tangent (δ) = 0.02 is used for the proposed antenna, and it has a compact size of 58 × 45 × 1.6 mm 3 .