A Survey and Comparison of Device-to-Device Architecture Using LTE Unlicensed Band

© 2017 IEEE. Due to the rapid increase in data traffic, one of the solutions provided by mobile operators is to operate Long Term Evolution (LTE) in the unlicensed 5GHz band, as the licensed spectrum is becoming scarce. Mobile operators can expand their network capacity by operating LTE in the unlicensed band at lower cost when compared with using other licensed bands. Device to Device (D2D) communication, proven to be another effective way to enhance the capacity of a network, enables direct data exchange of localized traffic of users in proximity. Applying D2D communication to LTE unlicensed 5GHz band will further improve the network performance and user experience. In this article, we will discuss the new type of solutions that have been proposed for LTE operating in an unlicensed 5GHz band that includes; LTE-Unlicensed (LTE-U), LTE-License Assisted Access (LTE-LAA), LTE WiFi Link Aggregation (LWA), and MuLTEfire. We will discuss the important features along with their advantages and disadvantages and compare these technologies as well. We simulate LTE-LAA, LWA and MuLTEfire technologies in the presence of Wi-Fi hotspot and compare their results. Furthermore, we apply D2D communication to these technologies and from the results we conclude that MuLTEfire can increase the throughput drastically but network saturates quickly. Whereas, applying D2D communication with LWA is beneficial for a scalable network as it will not only increase the network throughput but will increase the network capacity as well

Fairness-Oriented Link Scheduling for a D2D-enabled LTE-U/Wi-Fi Coexistence Network

To avoid spectrum crunch and improve spectrum efficiency, the use of unlicensed spectra and the introduction of D2D communication will be areas of focus in communication development. However, in the existing unlicensed spectrum coexistence mechanism, different ways of communication are seen as hindering each other. In this paper, we deliberate the coexistence of a D2D-enabled LTE network with Wi-Fi under an unlicensed band. Unlike previous coexistence mechanisms, we allow co-channel transmission, and our goal is to make full use of the advantages of D2D proximity communication and achieve fairness in co-channel transmission. First, we modeled the coexistence network and derived the expressions coverage probability of all types of receivers. Based on the analytical model and simulation results, we prove that D2D communication can be exploited to achieve fairness requirements in co-channel transmission over the unlicensed band. We rephrase the fairness schedule problem as a mixed-integer nonlinear optimization problem for D2D density and transmit power, and we use an Ortho-MADS algorithm to solve it. The simulation results show that the proposed scheme can use D2D communication to improve the fairness of the system

TECNOLOGÍAS DE ACCESO DINÁMICO Y USO COMPARTIDO DEL ESPECTRO

Purpose ”“ The quest to reduce the digital divide and increasing the traffic capacity of mobile networks to meet the demand for future connectivity led the Federal Institute of Telecommunications (IFT), through the Directorate of Engineering and Technology. Methodology ”“ Analysis of the state of the art of the technologies of dynamic access and shared use of the radioelectric spectrum (TADUCE) in order to identify those that are susceptible to adoption in Mexico. The technologies analyzed in the research are those based on LTE (Long Term Evolution) that operate in frequency bands of free use, emerging technologies based on MIMO, Cognitive Radio (RC), Device-to-Device (D2D) and TV White Spaces (TVWS) communications. Findings ”“ The DIT establishes different recommendations that the IFT must consider in order for these technologies to be optimally implemented in the country.Propósito ”“ En su preocupación por reducir la brecha digital y en busca de incrementar la capacidad de tráfico de las redes móviles para satisfacer la demanda de conectividad futura, el Instituto Federal de Telecomunicaciones (IFT), a través de la Dirección de Ingeniería y Tecnología (DIT). Metodologia ”“ Analize del estado del arte de las tecnologías de acceso dinámico y uso compartido del espectro radioeléctrico (TADUCE) con la finalidad de identificar aquellas que sean susceptibles de adopción en México. Las tecnologías analizadas en la investigación son aquellas basadas en LTE (Long Term Evolution) que operan en bandas de frecuencia de uso libre; tecnologías emergentes basadas en MIMO; Radio Cognitivo (RC); Comunicaciones Device-to-Device (D2D) y TV White Spaces (TVWS). Resultados ”“ La DIT establece diferentes recomendaciones que el IFT debe considerar para que dichas tecnologías se implementen óptimamente en el país.Propósito ”“ En su preocupación por reducir la brecha digital y en busca de incrementar la capacidad de tráfico de las redes móviles para satisfacer la demanda de conectividad futura, el Instituto Federal de Telecomunicaciones (IFT), a través de la Dirección de Ingeniería y Tecnología (DIT). Metodologia ”“ Analize del estado del arte de las tecnologías de acceso dinámico y uso compartido del espectro radioeléctrico (TADUCE) con la finalidad de identificar aquellas que sean susceptibles de adopción en México. Las tecnologías analizadas en la investigación son aquellas basadas en LTE (Long Term Evolution) que operan en bandas de frecuencia de uso libre; tecnologías emergentes basadas en MIMO; Radio Cognitivo (RC); Comunicaciones Device-to-Device (D2D) y TV White Spaces (TVWS). Resultados ”“ La DIT establece diferentes recomendaciones que el IFT debe considerar para que dichas tecnologías se implementen óptimamente en el país

Energy and throughput efficient strategies for heterogeneous future communication networks

As a result of the proliferation of wireless-enabled user equipment and data-hungry applications, mobile data traffic has exponentially increased in recent years.This in-crease has not only forced mobile networks to compete on the scarce wireless spectrum but also to intensify their power consumption to serve an ever-increasing number of user devices. The Heterogeneous Network (HetNet) concept, where mixed types of low-power base stations coexist with large macro base stations, has emerged as a potential solution to address power consumption and spectrum scarcity challenges. However, as a consequence of their inflexible, constrained, and hardware-based configurations, HetNets have major limitations in adapting to fluctuating traffic patterns. Moreover, for large mobile networks, the number of low-power base stations (BSs) may increase dramatically leading to sever power consumption. This can easily overwhelm the benefits of the HetNet concept. This thesis exploits the adaptive nature of Software-defined Radio (SDR) technology to design novel and optimal communication strategies. These strategies have been designed to leverage the spectrum-based cell zooming technique, the long-term evolution licensed assisted access (LTE-LAA) concept, and green energy, in order to introduce a novel communication framework that endeavors to minimize overall network on-grid power consumption and to maximize aggregated throughput, which brings significant benefits for both network operators and their customers. The proposed strategies take into consideration user data demands, BS loads, BS power consumption, and available spectrum to model the research questions as optimization problems. In addition, this thesis leverages the opportunistic nature of the cognitive radio (CR) technique and the adaptive nature of the SDR to introduce a CR-based communication strategy. This proposed CR-based strategy alleviates the power consumption of the CR technique and enhances its security measures according to the confidentiality level of the data being sent. Furthermore, the introduced strategy takes into account user-related factors, such as user battery levels and user data types, and network-related factors, such as the number of unutilized bands and vulnerability level, and then models the research question as a constrained optimization problem. Considering the time complexity of the optimum solutions for the above-mentioned strategies, heuristic solutions were proposed and examined against existing solutions. The obtained results show that the proposed strategies can save energy consumption up to 18%, increase user throughput up to 23%, and achieve better spectrum utilization. Therefore, the proposed strategies offer substantial benefits for both network operators and users