Editorial

3 pages, 151 KiB

Open AccessEditorial

Optical Communications and Networking Solutions for the Support of C-RAN in a 5G Environment

by Vincenzo Eramo, Marco Listanti and Francesco Giacinto Lavacca

Appl. Sci. 2019, 9(3), 414; https://doi.org/10.3390/app9030414 - 26 Jan 2019

Cited by 1 | Viewed by 1811

The widespread availability of mobile devices such as tablets and smartphones has led to fast-increasing mobile data traffic in the last few years [...] Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

Research

Jump to: Editorial

16 pages, 2385 KiB

Open AccessArticle

Impact of the Maximum Number of Switching Reconfigurations on the Cost Saving in Network Function Virtualization Environments with Elastic Optical Interconnection

by Vincenzo Eramo, Francesco G. Lavacca and Tiziana Catena

Appl. Sci. 2019, 9(23), 5167; https://doi.org/10.3390/app9235167 - 28 Nov 2019

Viewed by 1566

Abstract

Network Function Virtualization is based on the virtualization of the network functions and it is a new technology allowing for a more flexible allocation of cloud and bandwidth resources. In order to employ the flexibility of the technology and to adapt its use [...] Read more.

Network Function Virtualization is based on the virtualization of the network functions and it is a new technology allowing for a more flexible allocation of cloud and bandwidth resources. In order to employ the flexibility of the technology and to adapt its use according to the traffic variation, reconfigurations of the cloud and bandwidth resources are needed by means of both migration of the Virtual Machines executing the network functions and reconfiguration of circuits interconnecting the Virtual Machines. The objective of the paper is to study the impact of the maximum number of switch reconfigurations on the cost saving that the Networking Function Virtualization technology allows us to achieve. The problem is studied in the case of a scenario with an elastic optical network interconnecting datacenters in which the Virtual Machines are executed. The problem can be formulated as an Integer Linear Programming one introducing a constraint on the maximum number of switch reconfigurations but due to its computational complexity we propose a low computational complexity heuristic allowing for results close to the optimization ones. The results show how the limitation on the number of possible reconfigurations has to be taken into account to evaluate the effectiveness in terms of cost saving that the Virtual Machine migrations in Network Function Virtualization environment allows us to achieve. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Figure 1

17 pages, 430 KiB

Open AccessArticle

Optimizing C-RAN Backhaul Topologies: A Resilience-Oriented Approach Using Graph Invariants

by Valerio Frascolla, Cristina K. Dominicini, Marcia H. M. Paiva, Gilles Caporossi, Marcelo Antonio Marotta, Moises R. N. Ribeiro, Marcelo E. V. Segatto, Magnos Martinello, Maxwell E. Monteiro and Cristiano Bonato Both

Appl. Sci. 2019, 9(1), 136; https://doi.org/10.3390/app9010136 - 02 Jan 2019

Cited by 14 | Viewed by 3183

Abstract

At the verge of the launch of the first commercial fifth generation (5G) system, trends in wireless and optical networks are proceeding toward increasingly dense deployments, supporting resilient interconnection for applications that carry higher and higher capacity and tighter latency requirements. These developments [...] Read more.

At the verge of the launch of the first commercial fifth generation (5G) system, trends in wireless and optical networks are proceeding toward increasingly dense deployments, supporting resilient interconnection for applications that carry higher and higher capacity and tighter latency requirements. These developments put increasing pressure on network backhaul and drive the need for a re-examination of traditional backhaul topologies. Challenges of impending networks cannot be tackled by star and ring approaches due to their lack of intrinsic survivability and resilience properties, respectively. In support of this re-examination, we propose a backhaul topology design method that formulates the topology optimization as a graph optimization problem by capturing both the objective and constraints of optimization in graph invariants. Our graph theoretic approach leverages well studied mathematical techniques to provide a more systematic alternative to traditional approaches to backhaul design. Specifically, herein, we optimize over some known graph invariants, such as maximum node degree, topology diameter, average distance, and edge betweenness, as well as over a new invariant called node Wiener impact, to achieve baseline backhaul topologies that match the needs for resilient future wireless and optical networks. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Figure 1

13 pages, 9403 KiB

Open AccessArticle

Analysis of 5G New Radio Uplink Signals on an Analogue-RoF System Based on DSP-Assisted Channel Aggregation

by Befekadu D. Mengesha, Pablo Torres-Ferrera and Roberto Gaudino

Appl. Sci. 2019, 9(1), 47; https://doi.org/10.3390/app9010047 - 24 Dec 2018

Cited by 4 | Viewed by 5614

Abstract

The 3rd Generation Partnership Project (3GPP) is in the process of developing 5th generation (5G) radio access technology, the so-called new radio (NR). The aim is to achieve the performance requirements forIMT-2020 radio interface technology. In this paper, we focus on the analysis [...] Read more.

The 3rd Generation Partnership Project (3GPP) is in the process of developing 5th generation (5G) radio access technology, the so-called new radio (NR). The aim is to achieve the performance requirements forIMT-2020 radio interface technology. In this paper, we focus on the analysis of the transmission of 5G NR uplink physical channels, such as physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH), dedicated for data and control channels, respectively, as specified in the 3GPP standard, using digital signal processing (DSP)-assisted frequency division multiple access (FDMA) and time division multiple access (TDMA) channel aggregation techniques on an analogue radio-over-fiber (A-RoF) architecture. We verified that there is ~34% spectral efficiency gain and lower error vector magnitude (EVM) achieved using the TDMA technique. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Figure 1

18 pages, 2989 KiB

Open AccessArticle

A Genetic Algorithm for VNF Provisioning in NFV-Enabled Cloud/MEC RAN Architectures

by Lidia Ruiz, Ramón J. Durán, Ignacio De Miguel, Pouria S. Khodashenas, Jose-Juan Pedreño-Manresa, Noemí Merayo, Juan C. Aguado, Pablo Pavón-Marino, Shuaib Siddiqui, Javier Mata, Patricia Fernández, Rubén M. Lorenzo and Evaristo J. Abril

Appl. Sci. 2018, 8(12), 2614; https://doi.org/10.3390/app8122614 - 13 Dec 2018

Cited by 21 | Viewed by 5103

Abstract

5G technologies promise to bring new network and service capacities and are expected to introduce significant architectural and service deployment transformations. The Cloud-Radio Access Networks (C-RAN) architecture, enabled by the combination of Software Defined Networking (SDN), Network Function Virtualization (NFV) and Mobile Edge [...] Read more.

5G technologies promise to bring new network and service capacities and are expected to introduce significant architectural and service deployment transformations. The Cloud-Radio Access Networks (C-RAN) architecture, enabled by the combination of Software Defined Networking (SDN), Network Function Virtualization (NFV) and Mobile Edge Computing (MEC) technologies, play a key role in the development of 5G. In this context, this paper addresses the problems of Virtual Network Functions (VNF) provisioning (VNF-placement and service chain allocation) in a 5G network. In order to solve that problem, we propose a genetic algorithm that, considering both computing resources and optical network capacity, minimizes both the service blocking rate and CPU usage. In addition, we present an algorithm extension that adds a learning stage and evaluate the algorithm performance benefits in those scenarios where VNF allocations can be reconfigured. Results reveal and quantify the advantages of reconfiguring the VNF mapping depending on the current demands. Our methods outperform previous proposals in the literature, reducing the service blocking ratio while saving energy by reducing the number of active core CPUs. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Figure 1

12 pages, 323 KiB

Open AccessArticle

C-RAN Traffic Aggregation on Latency-Controlled Ethernet Links

by Federico Tonini, Bahare Masood Khorsandi, Steinar Bjornstad, Raimena Veisllari and Carla Raffaelli

Appl. Sci. 2018, 8(11), 2279; https://doi.org/10.3390/app8112279 - 18 Nov 2018

Cited by 3 | Viewed by 3009

Abstract

Centralized/Cloud Radio Access Networks (C-RAN) are deployed in converged fixed-mobile networks to exploit the flexibility coming from joint application of Network Function Virtualization (NFV) and Software Defined Networking (SDN). In this context, optical links connecting C-RAN nodes, possibly based on the Ethernet standards, [...] Read more.

Centralized/Cloud Radio Access Networks (C-RAN) are deployed in converged fixed-mobile networks to exploit the flexibility coming from joint application of Network Function Virtualization (NFV) and Software Defined Networking (SDN). In this context, optical links connecting C-RAN nodes, possibly based on the Ethernet standards, may carry traffic with different requirements in terms of latency and throughput. This paper considers the problem of traffic aggregation on C-RAN optical Ethernet links with latency control for fronthaul traffic and throughput capability for backhaul traffic. Integrated hybrid network technique is applied to show how time transparency can be enforced for Ethernet encapsulated Common Public Radio Interface (CPRI) traffic while allowing statistical multiplexing of backhaul traffic. Simulation results show the effectiveness of segmentation of backhaul traffic to allow exploitation of the available bandwidth even with high capacity CPRI options. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Graphical abstract

15 pages, 1744 KiB

Open AccessArticle

Traffic-Estimation-Based Low-Latency XGS-PON Mobile Front-Haul for Small-Cell C-RAN Based on an Adaptive Learning Neural Network

by Ahmed Mohammed Mikaeil, Weisheng Hu, Syed Baqar Hussain and Amber Sultan

Appl. Sci. 2018, 8(7), 1097; https://doi.org/10.3390/app8071097 - 06 Jul 2018

Cited by 18 | Viewed by 5462

Abstract

In this paper, we propose a novel method for low-latency 10-Gigabit-capable symmetric passive optical network (XGS-PON) mobile front-haul for small cell cloud radio access network (C-RAN) based on traffic estimation. In this method, the number of packets that arrive to the optical network [...] Read more.

In this paper, we propose a novel method for low-latency 10-Gigabit-capable symmetric passive optical network (XGS-PON) mobile front-haul for small cell cloud radio access network (C-RAN) based on traffic estimation. In this method, the number of packets that arrive to the optical network unit (ONU) buffer from the remote radio unit (RRU) link is predicted using an adaptive learning neural network function integrated into the dynamic bandwidth allocation (DBA) module at the optical line terminal (OLT). By using this predictive method, we are able to eliminate the additional DBA processing delay and the delay required for reporting ONU buffer occupancy to the OLT. As a result, the latency is as low as required for mobile front-haul in C-RAN architecture. The performance of the new method is evaluated by means of simulation under XGS-PON standard. The simulation results confirmed the capability of the proposed method of achieving the latency requirement for mobile front-haul while outperforming some other XGS-PON standard compliant algorithms that are optimized to support mobile front-haul and backhaul traffic. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures

Figure 1

16 pages, 873 KiB

Open AccessFeature PaperArticle

Dimensioning Models of Optical WDM Rings in Xhaul Access Architectures for the Transport of Ethernet/CPRI Traffic

by Vincenzo Eramo, Marco Listanti, Francesco G. Lavacca and Paola Iovanna

Appl. Sci. 2018, 8(4), 612; https://doi.org/10.3390/app8040612 - 12 Apr 2018

Cited by 19 | Viewed by 5072

Abstract

The Centralized Radio Access Network (C-RAN) provides a valid solution to overcome the problem of traditional RAN in scaling up to the needed processing resource and quality expected in 5G. The Common Public Rate Interface has been defined to transport traffic flows in [...] Read more.

The Centralized Radio Access Network (C-RAN) provides a valid solution to overcome the problem of traditional RAN in scaling up to the needed processing resource and quality expected in 5G. The Common Public Rate Interface has been defined to transport traffic flows in C-RAN and recently some market solutions are available. Its disadvantage is to increase by at least 10 times the needed bandwidth and for this reason its introduction will be gradual and will coexist with traditional RAN solutions in which Ethernet traffic is carried towards the radio base stations. In this paper, we propose an Xhaul optical network architecture based on Optical Transport Network (OTN) and Dense Wavelength Division Multiplexing (DWDM) technologies. The network allows for a dynamic allocation of the bandwidth resources according to the current traffic demand. The network topology is composed of OTN/DWDM rings and the objective of the paper is to evaluate the best configuration (number of rings and number of wavelengths needed) to both to minimize the cost and to provide an implementable solution. We introduce an analytical model for the evaluation of the number of wavelengths needed in each optical ring and provide some results for 5G case studies. We show how, although the single ring configuration provides the least cost solution due to the high statistical multiplexing advantage, it is not implementable because it needs switching apparatus with a too high number of ports. For this reason, more than one ring is needed and its value depends on several parameters as the offered traffic, the number of Radio Remote Units (RRU), the percentage of business sub-area and so on. Finally, the analytical model allows us to evaluate the advantages of the proposed dynamic resource allocation solution with respect to the static one in which the network is provided with a number of wavelengths determined in the scenario in which the radio station works at full load. The bandwidth saving can be in the order of 90% in a 5G traffic scenario. Full article

(This article belongs to the Special Issue Optical Communications and Networking Solutions for the Support of C-RAN in 5G Environments)

► Show Figures