IEEE/OSA Journal of Optical Communications and Networking

This short introductory paper sets the scene for this special edition of the Journal of Optical Communications and Networking, which is focused on elastic optical networks (EONs). A brief overview of the field is given, followed by a summary of the five invited papers. This special edition is designed to provide a review of current EON technology. View full abstract»

Common Public Radio Interface (CPRI) is a successful industry cooperation defining the publicly available specification for the key internal interface of radio base stations between the radio equipment control (REC) and the radio equipment (RE) in the fronthaul of mobile networks. However, CPRI is expensive to deploy, consumes large bandwidth, and currently is statically configured. On the other h... View full abstract»

Today's networks are quickly evolving toward more dynamic and flexible infrastructures and architectures. This software-based evolution has seen its peak with the development of the software-defined networking (SDN) and network functions virtualization (NFV) paradigms. These new concepts allow operators to automate the setup of services, thus reducing costs in deploying and operating the required ... View full abstract»

Low latency is of key importance for mobile networks to support emerging time-critical applications, such as road traffic safety and efficiency. Meanwhile, a passive optical network (PON) is widely recognized as a promising solution for mobile backhaul networks thanks to its high capacity and low energy consumption. In the conventional PON-based mobile backhaul network, where base stations (BSs) a... View full abstract»

This paper describes full service access network operator group perspectives on the feasibility of optical access networks to carry radio access network traffic for the existing and future mobile generations. The paper discusses topics related to the evolution of radio access interfaces, such as backhaul, midhaul, and fronthaul, their transmission through optical distribution networks, and passive... View full abstract»

Centralized processing is expected to bring about substantial benefits for wireless networks both on the technical side and on the economic side. While this concept is considered an important part of future radio access network architectures, it is more and more recognized that the current approach to fronthauling by employing the Common Public Radio Interface protocol will be inefficient for larg... View full abstract»

Visible light communication (VLC) using multiple-input multiple-output (MIMO) has great potential for future high-data-rate indoor wireless communications. Owing to the dual function of white light-emitting diodes (LEDs), i.e., illumination and communication functions, both the illumination and communication coverages need to be evaluated when implementing an indoor MIMO-VLC system. In this paper,... View full abstract»

This paper analyzes the performance of indoor orthogonal frequency division multiplexing (OFDM) optical wireless communication systems in the presence of light emitting diode (LED) nonlinear distortions. There are several forms of optical OFDM using intensity modulation [7th Int. Symp. on Communication Systems Networks and Digital Signal Processing (CSNDSP), 2010, pp. 566-570]. In this paper, DC-b... View full abstract»

With the advent of 5G, fixed wireless access (FWA) has emerged as a promising candidate for rolling out fixed broadband services. By means of radio simulations, we define a 5G radio deployment scenario for FWA that can meet the service requirements of future fixed broadband access. Different transport requirements imposed by different radio access network (RAN) split options are considered and a b... View full abstract»

In general, humans follow a routine with highly predictable daily movements. For instance, we commute from home to work on a daily basis and visit a selected set of places for commercial and recreational purposes during the nights and weekends. The use of mobile phones increases when commuting via public transportation, during lunch breaks, and at night. Such regular behavior creates predictable s... View full abstract»

The emerging field of optical wireless communications (OWC) offers exceptional promise as a technology for next-generation wireless networks. High data rate capabilities and ultra-dense access point deployment will allow OWC to supplement traditional RF technologies and remove congestion from the crowded RF spectrum. When implementing OWC via intensity modulation with direct detection (IM/DD), pea... View full abstract»

With the advancement of radio access networks, more and more mobile data content needs to be transported by optical networks. Mobile fronthaul is an important network segment that connects centralized baseband units (BBUs) with remote radio units in cloud radio access networks (C-RANs). It enables advanced wireless technologies such as coordinated multipoint and massive multiple-input multiple-out... View full abstract»

The performance of optical/wireless hybrid networks is largely limited by the wireless part. To reduce the wireless transmission, we configure virtual channels in the optical infrastructure as “shortcuts” between selected gateways. Adding virtual channels changes the network topology and affects the optimality of gateway deployment. Meanwhile, the gateway locations dictate the traffi... View full abstract»

In this paper, we employ a spatial multiplexing scheme with M transceivers to increase the data rate of a free-space optical (FSO) system. In our proposed scheme, each transmitter sends independent information toward the center of its related receiver aperture. We analyze the performance of the proposed scheme in terms of average achievable rate. To compare the performance of our proposed scheme w... View full abstract»

Time division multiplexing passive optical network (TDM-PON) technologies are viewed as an attractive solution for flexible and cost-efficient mobile front-haul for cloud radio access network (C-RAN) architecture. However, it is a challenge for TDM-PONs to meet the strict latency requirement of mobile front-haul in C-RAN because they use a dynamic bandwidth allocation (DBA) mechanism to manage ups... View full abstract»

We consider channel characterization for underwater wireless optical communication (UWOC) systems. We focus on the channel impulse response and, in particular, quantify the channel time dispersion for different water types, link distances, and transmitter/receiver characteristics, taking into account realistic parameters. We use the Monte Carlo approach to simulate the trajectories of emitted phot... View full abstract»

In this work, we compare 4-pulse amplitude modulation and on-off keying modulation formats at high speed for short-range optical communication systems. The transmission system comprised a directly modulated vertical-cavity surface-emitting laser operating at a wavelength of 850 nm, an OM3+ multimode fiber link, and a photodetector detecting the intensity at the receiver end. The modulation formats... View full abstract»

In this paper, a power and bandwidth efficient pulsed modulation technique for optical wireless (OW) communication is proposed. The scheme is called optical spatial modulation (OSM). In OSM, multiple transmit units exist where only one transmitter is active at any given time instance. The spatially separated transmit units are considered as spatial constellation points. Each unique sequence of inc... View full abstract»

We experimentally demonstrate high-quality real-time video streaming over an underwater wireless optical communication (UWOC) link up to 5 m distance using phase-shift keying (PSK) modulation and quadrature amplitude modulation (QAM) schemes. The communication system uses software defined platforms connected to a commercial TO-9 packaged pigtailed 520 nm directly modulated laser diode (LD) with 1.... View full abstract»

Visible light communication (VLC) turns indoor light-emitting diode (LED)-based illumination devices into high-speed network portals that, for example, operate in tandem with existing Wi-Fi networks. Since in this scenario, multiple VLC-equipped luminaires would serve overlapping service areas, we suggest the use of power line communication (PLC) to coordinate and provide data to the VLC transmitt... View full abstract»

In this paper, we discuss building blocks that enable the exploitation of optical capacities beyond 100 Gb/s. Optical networks will benefit from more flexibility and agility in their network elements, especially from coherent transceivers. To achieve capacities of 400 Gb/s and more, coherent transceivers will operate at higher symbol rates. This will be made possible with higher bandwidth componen... View full abstract»

We first experimentally demonstrated a digital mobile fronthaul (MFH) architecture using delta-sigma modulation as the new digitization interface to replace the conventional common public radio interface (CPRI). Both one-bit and two-bit delta-sigma modulations were demonstrated, and the digitized signals were transmitted over on-off keying (OOK) or 4-level pulse-amplitude-modulation (PAM4) optical... View full abstract»

Based on information-theoretic security, physical-layer security in an optical code division multiple access (OCDMA) system is analyzed. For the first time, the security leakage factor is employed to evaluate the physical-layer security level, and the safe receiving distance is used to measure the security transmission range. By establishing the wiretap channel model of a coherent OCDMA system, th... View full abstract»

In this paper, we propose an imperfect-quantized-feedback-based beamforming scheme for a generalized multiple-input single-output (MISO) free space optical (FSO) system over Gamma-Gamma fading channels with pointing error. It is well known that a feedback-based beamforming scheme aids channel adaptive signaling in wireless communication systems and provides large performance gain. If the feedback ... View full abstract»

We show that, in an optical packet-switching (OPS) network with bufferless switches, end-to-end congestion control algorithms can be designed to completely overcome the pernicious effects that the lack of buffers have on application throughput. Thus, applications can obtain the same throughputs in bufferless OPS as in equivalent electronic networks with plentiful buffers. There is no need to imple... View full abstract»

With the recent conclusion of the XGS-PON and NG-PON2 standards in the ITU-T, the fiber access industry is now considering where to go next. This paper reviews the passive optical network (PON) systems market and the services that will drive the take-up of these next-generation PON technologies. The drivers for future PON evolution are discussed, and some technology options for the evolution of PO... View full abstract»

In this work we investigate the use of network coding in 1 + 1 survivable IP-over-wavelength-divisionmultiplexing (WDM) networks by encoding the protection paths of multiple flows with each other at intermediate nodes. We study the energy efficiency of this scheme through mixed-integer linear programming (MILP) and a heuristic with five operating options. We evaluate the MILP and the heuristics on... View full abstract»

The paper offers a survey on recent advances in the technological platforms for photonic integrated optical transceivers and innovative transmission techniques supporting the capacity increase of optical networks, in view of forthcoming 5G requirements. Both indium phosphide (InP) and silicon (Si) platforms are considered, highlighting the most significant advantages of the two technologies and re... View full abstract»

Relay-assisted free-space optical (FSO) transmission exploits the fact that atmospheric turbulence fading variance is distance dependent and yields significant performance gains by taking advantage of the resulting shorter hops. In this paper, we investigate how to determine optimal relay locations in serial and parallel FSO relaying so as to minimize the outage probability and quantify performanc... View full abstract»

So much has been promised by the fifth generation (5G), the revolution of mobile communications that allows for flexible, speedy, and efficient delivery of unlimited data and information sharing between people located anywhere and at any time. The road toward making 5G a reality, however, requires concerted efforts in designing both the underlying infrastructure and the enabling technologies to si... View full abstract»

Time and wavelength division multiplexed passive optical network (TWDM-PON) standards dramatically increase the performance of PON systems and address ever-increasing demands for bandwidth. However, these schemes increase the complexity and energy consumption of PON systems because they exploit multiple wavelengths, which requires multiple transceivers in the optical line terminal (OLT). In this p... View full abstract»

Future 5G networks will bring important challenges to network operators, such as the traffic load increase mainly due to the proliferation of mobile broadband communications. This will force mobile network operators (MNOs) redesigning and investing in their infrastructures [e.g., new equipment for radio access network (RAN), backhaul] to cope with such data growth. Aiming at lowering both capital ... View full abstract»

We investigate the performance of asymmetric radio frequency (RF) and free-space optical (FSO) dual-hop cognitive amplify-and-forward relay networks where RF links are subject to independent and nonidentically distributed Nakagami-m fading. We consider that the RF link transmitter and receiver are secondary users of an underlay cognitive network. Specifically, the transmit power conditions of the ... View full abstract»

We propose a novel technique for simultaneous multi-impairment monitoring and autonomous bit-rate and modulation format identification (BR-MFI) in next-generation heterogeneous fiber-optic communication networks by using principal component analysis-based pattern recognition on asynchronous delay-tap plots. The results of numerical simulations performed for three commonly used modulation formats a... View full abstract»

This paper proposes to empower capacityand coverage-centric fiber-wireless (FiWi) enhanced 4G LongTerm Evolution Advanced (LTE-A) heterogeneous networks (HetNets) with computationand storage-centric mobile cloud computing to cope with the unprecedented growth of mobile data traffic. Minimizing energy consumption and maximizing revenue while offloading mobile data in such highly converged and hiera... View full abstract»

Numerous studies have investigated elastic optical networks (EONs) with the aim of expanding the transmission capacities of core networks. To achieve this goal, it is necessary to solve the spectrum resource wastage problem caused by spectrum fragmentation. Moreover, due to the potentially high traffic demands in future networks, it is important to handle requests that need to be reserved immediat... View full abstract»

As traffic volumes carried by optical networks continue to grow by tens of percent year over year, we are rapidly approaching the capacity limit of the conventional communication band within a single-mode fiber. New measures such as elastic optical networking, spectral extension to multi-bands, and spatial expansion to additional fiber overlays or new fiber types are all being considered as potent... View full abstract»

Although a restoration approach derives a reroute path when failure occurs and greatly reduces forwarding rules in switches compared with a protection approach, software-defined networks (SDNs) induce a long failure recovery process because of frequent flow operations between the SDN controller and switches. Accordingly, it is indispensable to design a new resilience approach to balance failure re... View full abstract»

Multiple-input multiple-output (MIMO) is a natural and effective way to increase the capacity of white light-emitting diode (LED) based visible light communication (VLC) systems. Orthogonal frequency division multiplexing (OFDM) using high-order modulation is another widely used technique in VLC systems. Due to the intensity modulation and direct detection nature of VLC systems, Hermitian symmetry... View full abstract»

Resource allocation with quality of service constraints is one of the most challenging problems in elastic optical networks that is normally formulated as a mixed-integer nonlinear optimization program. In this paper, we focus on novel properties of geometric optimization and provide a heuristic approach for resource allocation that is much faster than its mixed-integer nonlinear counterpart. Our ... View full abstract»

Visible light communication (VLC) is a promising complementary technology to its radio frequency (RF) counterpart. Heterogeneous VLC-WiFi systems offer a solution for future indoor communications that combines VLC to support high data rate transmission and RF to support reliable connectivity. In such heterogeneous systems, vertical handover (VHO) is critical for improving the system performance. T... View full abstract»

The fifth generation of mobile communication is characterized by ultra-dense cellular networks, where massive small cells are deployed in hot spots to increase the network capacity. As a promising technology in the small-cell scenario, coordinated multipoint (CoMP) is proposed to improve cell-edge user throughput by converting inter-cell interference into useful signals. In this paper, we study ho... View full abstract»

We investigate transmitter IQ imbalance compensation based on the blind adaptive source separation (BASS) method in a dual-polarization M-QAM optical coherent system. The robustness of the BASS method against the residual carrier frequency offset (CFO) is numerically investigated and compared to that of the Gram-Schmidt orthogonalization procedure (GSOP). We further validate experimentally the pro... View full abstract»

In this paper, we study the performance of a space shift keying (SSK) scheme in a free-space optical (FSO) communication system under indoor and outdoor conditions. For the outdoor Nt × 1 FSO-SSK system, where Nt is the number of transmitters (Txs), a novel closed-form mathematical expression for the probability density function (pdf) of the difference between two weig... View full abstract»

We experimentally evaluate the mobile fronthaul (MFH) optical bandwidth and wireless coordinated multipoint (CoMP) transmission and reception performance in Ethernet-based MFH with our proposed split-physical (PHY) processing (SPP). To reduce the MFH optical bandwidth, SPP redefines the base station (BS) functional split between the baseband unit (BBU) and the remote radio head (RRH) in a centrali... View full abstract»

Traditional data centers (DCs) that are located in distant areas usually lack flexibility and also have long service latency for metro users. On the other hand, the recently introduced and implemented metro-embedded data center (ME-DC) architecture, based on micro-data centers (mDCs), delivers more flexible services with less access latency. Hierarchical software-defined network control is employe... View full abstract»

The explosion of mobile traffic requires fronthaul networks to provide huge data capacity. One straightforward solution is to use wavelength division multiplexing (WDM) technologies with a sufficient number of transceivers, but the massive deployment of fronthaul networks inevitably adds transceiver cost. In this paper, we propose and demonstrate a low-cost scheme using a partitioned asymmetric ar... View full abstract»

Hybrid fiber-wireless (FiWi) networks, which benefit from high bandwidth and ubiquitous access of optical and wireless networks, have been identified as a promising technology candidate for next-generation broadband access. As various component/fiber failures may occur in hybrid FiWi networks, thus affecting huge numbers of end users, survivability has become one of the key important deployment co... View full abstract»

With the continuing growth in the amount of backbone traffic, improving the cost-effectiveness and ensuring survivability of the underlying optical networks are very important problems facing network service providers today. In this paper, we propose a bandwidth squeezed restoration (BSR) scheme in our recently proposed spectrum-sliced elastic optical path network (SLICE). The proposed BSR takes a... View full abstract»

Increasing the contact bandwidth in delay tolerant networks (DTNs) via multicopy routing leads to a decrease in data delivery delay and an improvement in throughput. In DTNs, in which nodes have both radio frequency (RF) and free space optical (FSO) PHY layers, contact bandwidth can be increased by using the FSO PHY as the data channel and performing multicasting. As we show in this paper, due to ... View full abstract»