Content Delivery Analysis in Multiple Devices to Single Device Communications

Content caching at mobile user devices (UDs) utilizing device to device (D2D) communications is a promising technology to enhance the performance of mobile networks, in terms of latency, throughput, energy consumption, and so on. In this paper, a novel method of content delivery using multiple devices to single device (MDSD) communications through D2D links is presented. In this method, the Zipf distribution with exponent shape parameter is adopted to model the content caching popularity for the analysis of the achievable signal to interference plus noise ratio (SINR). In order to investigate the advantage of the proposed MDSD method, firstly, a closedform expression of the outage probability is theoretically derived for a single D2D communication to evaluate the success of content delivery to a reference UD. Secondly, the expression of the outage probability for MDSD communication is derived, where the outage probability is modeled as a function of content caching popularity, the density of UDs, and the size of cooperative area. The research work is further extended to address the frequency reuse among different UDs in one cell, where a frequency band factor is introduced, and the optimal radius of the cooperative area is introduced and analysed. The analytical results, validated by the simulation results, show that the outage probability decreases drastically when the popularity of the content increases, or the radius of the cooperative area increases. Using the given closed-form expression of the outage probability, the area spectral efficiency (ASE) of the system is presented. Furthermore, the results show that as the frequency band factor increases, the outage probability decreases, as well as the ASE decreases. Finally, it is shown that the MDSD outperforms the single D2D-based method

Design and application of intelligent reflecting surface (IRS) for beyond 5G wireless networks: a review

The existing sub-6 GHz band is insufficient to support the bandwidth requirement of emerging data-rate-hungry applications and Internet of Things devices, requiring ultrareliable low latency communication (URLLC), thus making the migration to millimeter-wave (mmWave) bands inevitable. A notable disadvantage of a mmWave band is the significant losses suffered at higher frequencies that may not be overcome by novel optimization algorithms at the transmitter and receiver and thus result in a performance degradation. To address this, Intelligent Reflecting Surface (IRS) is a new technology capable of transforming the wireless channel from a highly probabilistic to a highly deterministic channel and as a result, overcome the significant losses experienced in the mmWave band. This paper aims to survey the design and applications of an IRS, a 2-dimensional (2D) passive metasurface with the ability to control the wireless propagation channel and thus achieve better spectral efficiency (SE) and energy efficiency (EE) to aid the fifth and beyond generation to deliver the required data rate to support current and emerging technologies. It is imperative that the future wireless technology evolves toward an intelligent software paradigm, and the IRS is expected to be a key enabler in achieving this task. This work provides a detailed survey of the IRS technology, limitations in the current research, and the related research opportunities and possible solutions

Video content delivery using multiple devices to single device communications

Content caching between multiple devices to single device (MD2SD) using device to device (D2D) link is studied for mobile communications in this paper. A general outage probability for video content delivery using the popularity and storage size of the user equipment (UE) is derived. This outage probability is modelled as a function of popularity of video, storage size, and signal to interference plus noise ratio (SINR). Our main contribution is the closed form expression and a very close tractable approximation. From the simulation results, it can be observed that as the popularity of the video increases, the outage probability of the system can be decreased substantially. Furthermore, it is analysed that improving the storage space on the UE decreases the outage probability of the system