In narrowband communication system, the presence of interference and noise are normally modeled by Gaussian distribution. However, it is not always the case for broadband signals. In this paper, we study the statistical distribution of a singleuser Ultra Wideband system in the presence of intersymbol interference and the additive white Gaussian noise. Simulated distribution model has been done by collecting the data of the conditional probability density function at the receiver output. Results show that the Middleton ClassA distribution model is more preferable in the presence of lineofsight path, but not in nonlineofsight path.
Due to the extremely short pulse duration, ultra wideband (UWB) signals entail long impulse responses that cause severe intersymbol interference (ISI). In this paper, we propose a low-complexity equalizer based on the minimum bit error rate (MBER) criterion for ISI mitigation in realistic UWB channels. Results showed that the proposed equalizer with shorter filter length and same level of complexity can achieve better performance as compared to equalizers based on the minimum mean square error (MMSE) criterion. Keywords: ultra wideband, intersymbol interference, minimum mean square error, minimum bit error rate Classification: Microwave and millimeter wave devices, circuits, and systems
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Increased capacity, higher data rate, decreased latency, and better service quality are examples of the primary objectives or needs that must be catered to in the near future, i.e., fifth-generation (5G) and beyond. To fulfil these needs, cellular network design must be drastically improved. The 5G cellular network design, huge multiple-input multiple-output (MIMO) technology, and device-to-device communication are all highlighted in this comprehensive study. Hence, free-space optics (FSO) is a promising solution to address this field. However, FSO standalone is insufficient during turbulent weather conditions. FSO systems possess some limitations, such as being able to be disturbed by any interference between sender and receiver such as a flying bird and a tree, as it requires line-of-sight (LOS) connectivity. Moreover, it is sensitive to weather conditions; the FSO performance significantly decreases in bad weather conditions such as fog and snow; those factors deteriorate the performance of FSO. This paper conducts a systematic survey on the existing projects in the same area of research such as the hybrid FSO/Radio frequency (RF) communication system by listing each technique used for each model to achieve optimum performance in terms of data rate and Bit Error Rate (BER) to be implemented in 5G networks.
Attribute-based encryption (ABE) cryptography is widely known for its potential to solve the scalability issue of recent public key infrastructure (PKI). It provides a fine-grained access control system with high flexibility and efficiency by labeling the secret key and ciphertext with distinctive attributes. Due to its fine-grained features, the ABE scheme is a protection layer in securing users’ data and privacy in big data processing and analytics. However, quantum computing, new technology on the horizon that will transform the security and privacy environment, has begun to appear. Like the conventional ABE schemes, present cryptography is not excluded from the impacts of quantum technology as they are not made to be quantum-resistant. While most recent surveys generally touched on the generic features of attribute-based encryption schemes such as user revocation, scalability, flexibility, data confidentiality, and scope in pairing-based ABE schemes, this survey investigated quantum-resistant ABE schemes in securing big data. This survey reviews the challenges faced by the recent ABE cryptography in the post-quantum era and highlights its differences from the conventional pairing-based ABE schemes. Subsequently, we defined the criteria of an ideal quantum-resistant ABE scheme. Additionally, existing works on quantum-resistant ABE schemes are reviewed based on their algorithms design, security and functionalities. Lastly, we summarized quantum-resistant ABE schemes’ ongoing challenges and future works.
The continuous development of online social services and the ever-increasing number of devices demanding high-speed and ubiquitous broadband wireless access have resulted in severe bandwidth congestion, such that the radio frequency (RF) spectrum will no longer be able to support the exponential growth in demand. Along with being faster, cheaper, greener, cleaner, and safer than current technology, visible light communication (VLC) can overcome the bottleneck issues with last-mile connectivity by offering 10, 000 times broader bandwidth. In this paper, we propose a system with portable, low-cost hybrid RF/VLC and free-space optics (FSO) transceivers with a simple graphical user interface and the capability of indoor wireless communication and multimedia broadcasting, thus presenting an economical and cable-free solution to various multimedia applications, such as file transmission and real-time audio and video streaming. The proposed system deploys VLC as a hotspot for data broadcasting within an enclosed room, FSO as the backbone for data transmission between multiple rooms, and Wi-Fi for lights-off mode. Preliminary results show a transmission rate of 1kbps at a maximum distance of 4 cm.
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