Antonio De Domenico

Cloud technologies for flexible 5G radio access networks

The evolution toward 5G mobile networks will be characterized by an increasing number of wireless devices, increasing device and service complexity, and the requirement to access mobile services ubiquitously. Two key enablers will allow the realization of the vision of 5G: very dense deployments and centralized processing. This article discusses the challenges and requirements in the design of 5G mobile networks based on these two key enablers. It discusses how cloud technologies and flexible functionality assignment in radio access networks enable network densification and centralized operation of the radio access network over heterogeneous backhaul networks. The article describes the fundamental concepts, shows how to evolve the 3GPP LTE architecture, and outlines the expected benefits.

Millimeter-wave access and backhauling: the solution to the exponential data traffic increase in 5G mobile communications systems?

The exponential increase of mobile data traffic requires disrupting approaches for the realization of future 5G systems. In this article, we overview the technologies that will pave the way for a novel cellular architecture that integrates high-data-rate access and backhaul networks based on millimeter-wave frequencies (57-66, 71-76, and 81-86 GHz). We evaluate the feasibility of short- and medium-distance links at these frequencies and analyze the requirements from the transceiver architecture and technology, antennas, and modulation scheme points of view. Technical challenges are discussed, and design options highlighted; finally, a performance evaluation quantifies the benefits of millimeter- wave systems with respect to current cellular technologies.

Enabling 5G backhaul and access with millimeter-waves

This paper presents the approach of extending cellular networks with millimeter-wave backhaul and access links. Introducing a logical split between control and user plane will permit full coverage while seamlessly achieving very high data rates in the vicinity of mm-wave small cells.

Towards a flexible functional split for cloud-RAN networks

Very dense deployments of small cells are one of the key enablers to tackle the ever-growing demand on mobile bandwidth. In such deployments, centralization of RAN functions on cloud resources is envisioned to overcome severe inter-cell interference and to keep costs acceptable. However, RAN back-haul constraints need to be considered when designing the functional split between RAN front-ends and centralized equipment. In this paper we analyse constraints and outline applications of flexible RAN centralization.

A backhaul-aware cell selection algorithm for heterogeneous cellular networks

This paper considers heterogeneous cellular networks, where cluster of small cells are deployed to create local hot spots inside the macro cell. In the past, most of the research in this topic has focused on mitigating inter cell interference; however, wireless backhaul has recently emerged as an urgent challenge to enable ubiquitous broadband wireless services at small cells. Hence, we propose a novel cell selection framework, which associates users and heterogeneous access nodes to improve the efficiency in the overall radio and backhaul resource utilization and avoid load congestions. We also model the relationships amongst cell load, resource management, backhaul capacity constraints, and the overall network capacity. Then, we describe the cell selection problem and we present a heuristic algorithm, named as Evolve, to solve it with limited complexity. Our analysis shows that Evolve achieves near optimal performance leading to notable capacity improvements with respect to the classic SINR based association scheme.

Green framework for future heterogeneous wireless networks

Energy-efficient communication has sparked tremendous interest in recent years as one of the main design goals of future wireless Heterogeneous Networks (HetNets). This has resulted in paradigm shift of current operation from data oriented to energy-efficient oriented networks. In this paper, we propose a framework for green communications in wireless HetNets. This framework is cognitive in holistic sense and aims at improving energy efficiency of the whole system, not just one isolated part of the network. In particular, we propose a cyclic approach, named as energy-cognitive cycle, which extends the classic cognitive cycle and enables dynamic selection of different available strategies for reducing the energy consumption in the network while satisfying the quality of service constraints.

Dynamic Traffic Management for Green Open Access Femtocell Networks

The exponential increase in high rate traffic driven by the new generation of wireless services is expected to overload cellular network capacity in the near future. Femtocell networks have recently been proposed as an efficient and cost-effective solution to enhance cellular network capacity and coverage. However, dense and unplanned deployment of new Base Stations (BSs) and their uncoordinated operation may increase the system power consumption and rise co-channel interference. Thus, efficient schemes are essential for managing femtocell activity and improving the system performance. Classical cell switch off and discontinuous transmission (DTX) algorithms aim at improving the network Energy Efficiency (EE) in lightly loaded scenarios. In this paper, we propose a novel multi-cell architecture for Open Access femtocell networks, which also enables energy saving at medium and high loads without compromising the end-user performance.

On the impact of backhaul network on distributed cloud computing

Nowadays, heterogeneous networks are seen as a key enabler to meet the challenging performance required for the evolution of LTE networks. At the same time, cloud computing is an emerging trend that outsources computing and storage resources, and extends mobile handsets capability of processing large data amounts. Cooperation in heterogeneous networks allows better (improved) network management by reducing power consumption, enhancing network coverage, and reducing deployment and communication costs. Within the cloud paradigm, federating femtocells in clusters not only helps with network management, but also opens the possibility to use these clusters for both communication and computation. Clusters of femtocells with virtual machine hosting capabilities is a novel disruptive paradigm which adds a dimension to cooperative management of heterogeneous networks. However, effective cooperation among geographically neighboring femtocells is prone to backhauling energy costs and delay limitations. In this paper, we propose a framework for evaluating backhauling performance in a femto-cloud architecture, considering several backhaul technologies and topologies. Our simulations explicit the limitations of clustering in femto-cloud imposed by backhauling.

Ghost femtocells: A novel radio resource management scheme for OFDMA based networks

The femtocell deployment in 3GPP/LTE sets new challenges to interference mitigation techniques and Radio Resource Management (RRM). Traditional schemes are mainly designed for classical cellular networks while the ad hoc nature of femtocells notably limits the complexity of possible algorithms. Thus, efficient RRM schemes are essential for limiting the interference impact on end-user performance. The goal of this paper is to achieve effective spectral reuse between macrocells and femtocells while guaranteeing the QoS of users served by both macro and femto base stations. We propose a novel resource management scheme that limits the overall interference per chunk generated outside the coverage range of a femtocell while reducing the transmission power in each Resource Block (RB). Our simulation results show that the proposed RRM scheme enhances the energy efficiency of femtocells and improves both macrocell and femtocell throughput.

A Radio Resource Management scheduling algorithm for self-organizing femtocells

3GPP/LTE femtocell dense deployment scenarios set new challenges in terms of interference and Radio Resource Management (RRM). Traditional policies are mainly designed for classical cellular networks, while femtocells ad-hoc nature notably limits the possible algorithm complexity. Furthermore, efficient RRM algorithms are essential in limiting interference impact to femtocells performance. In this paper we propose a novel resource scheduling algorithm which improves spectral reuse while reducing the transmission power in each Resource Block (RB). Simulation results show that the proposed RRM scheme enhances femtocells spectral efficiency and coverage.