http://www.acsu.buffalo.edu/~jmjornet/papers/2014/j1.pdf

Full length article: Terahertz band: Next frontier for wireless communications

The Internet of Things vision: Key features, applications and open issues

The days where swarms of unmanned aerial vehicles (UAVs) will occupy our skies are fast approaching due to the introduction of cost-efficient and reliable small aerial vehicles and the increasing demand for use of such vehicles in a plethora of civil applications. Governments and industry alike have been heavily investing in the development of UAVs. As such it is important to understand the characteristics of networks with UAVs to enable the incorporation of multiple, coordinated aerial vehicles into the air traffic in a reliable and safe manner. To this end, this survey reports the characteristics and requirements of UAV networks for envisioned civil applications over the period 2000–2015 from a communications and networking viewpoint. We survey and quantify quality-of-service requirements, network-relevant mission parameters, data requirements, and the minimum data to be transmitted over the network. Furthermore, we elaborate on general networking related requirements such as connectivity, adaptability, safety, privacy, security, and scalability. We also report experimental results from many projects and investigate the suitability of existing communication technologies for supporting reliable aerial networking.

Survey on Unmanned Aerial Vehicle Networks for Civil Applications: A Communications Viewpoint

The fifth generation (5G) mobile networks are envisioned to support the deluge of data traffic with reduced energy consumption and improved quality of service (QoS) provision. To this end, key enabling technologies, such as heterogeneous networks (HetNets), massive multiple-input multiple-output (MIMO), and millimeter wave (mmWave) techniques, have been identified to bring 5G to fruition. Regardless of the technology adopted, a user association mechanism is needed to determine whether a user is associated with a particular base station (BS) before data transmission commences. User association plays a pivotal role in enhancing the load balancing, the spectrum efficiency, and the energy efficiency of networks. The emerging 5G networks introduce numerous challenges and opportunities for the design of sophisticated user association mechanisms. Hence, substantial research efforts are dedicated to the issues of user association in HetNets, massive MIMO networks, mmWave networks, and energy harvesting networks. We introduce a taxonomy as a framework for systematically studying the existing user association algorithms. Based on the proposed taxonomy, we then proceed to present an extensive overview of the state-of-the-art in user association algorithms conceived for HetNets, massive MIMO, mmWave, and energy harvesting networks. Finally, we summarize the challenges as well as opportunities of user association in 5G and provide design guidelines and potential solutions for sophisticated user association mechanisms.

/pdf/user-association-in-5g-networks-a-survey-and-an-outlook-4zdf9nh1ox.pdf

User Association in 5G Networks: A Survey and an Outlook

5G roadmap

Full length article: LTE-Advanced and the evolution to Beyond 4G (B4G) systems

Cellular network technologies have traditionally evolved to meet the ever-increasing need for capacity and coverage. Particularly, there has been a significant focus on exploiting the use of small cells and heterogeneous networks (HetNets). In the latter, the economic and environmental impact of the energy consumption is a key concern. Although much research has been done to address the energy consumption in HetNets, existing approaches have failed to capture the key factors affecting it. In this paper, the energy consumption in HetNets is analyzed with a focus on their multi-layer nature and the dependence of the energy consumption on the spatio-temporal traffic demands and the internal base station hardware components. The problem of minimizing the energy consumption is then studied and characterized in terms of a 0-1 Knapsack-like problem. Due to the differences with the classical 0-1 Knapsack problem, an efficient algorithm is introduced to minimize the energy consumption by adjusting the cell-association and the base stations on-off policies. Such algorithm is shown to be applicable to the two- and $m$ -layer HetNet cases. Performance evaluation is provided to identify the achievable energy savings of our algorithm and its effect on the energy consumption, activity, and load across multiple layers.

Energy Consumption Analysis and Minimization in Multi-Layer Heterogeneous Wireless Systems

Multi-stream carrier aggregation (MSCA) has been recently proposed as a mechanism to increase the amount of bandwidth available to users for heterogeneous networks (HetNets) in 5G wireless systems. Previous studies have focused only on maximizing the network capacity and fairness, without considering the energy efficiency of the MSCA. In this paper, the use of MSCA to minimize the energy consumption in a multi-layer HetNet is studied. The convexity of the energy minimization problem is examined, leading to the need of a quasi-convex relaxation. With this approximation, an algorithm bisection method for energy minimization is designed to solve the energy minimization problem and obtains an optimum cell-association policy. Since the operators are generally interested in a balance between the energy minimization and capacity maximization, such multi-objective optimization is needed, and we studied it in this paper. The two aforementioned conflicting objectives can be jointly analyzed and solved through scalarization, even though the energy minimization has a quasi-convex objective function, and not a convex one. Performance evaluation is provided to identify the achievable energy savings of our proposed algorithm and to characterize the tradeoffs between the energy minimization and capacity maximization in a multi-layer HetNet in 5G systems that support MSCA.

Elias Chavarria-Reyes

Papers

Full length article: LTE-Advanced and the evolution to Beyond 4G (B4G) systems

Energy Consumption Analysis and Minimization in Multi-Layer Heterogeneous Wireless Systems

Energy-Efficient Multi-Stream Carrier Aggregation for Heterogeneous Networks in 5G Wireless Systems

Enabling next generation small cells through femtorelays

Reducing the energy consumption at the user equipment through multi-stream cross-carrier-aware discontinuous reception (DRX) in LTE-advanced systems