Showing papers on "10G-PON published in 2016"

Emerging Optical Access Network Technologies for 5G Wireless [Invited]

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-output. Mobile backhaul, on the other hand, connects BBUs with core networks to transport the baseband data streams to their respective destinations. Optical access networks are well positioned to meet the first optical communication demands of C-RANs. To better address the stringent requirements of future generations of wireless networks, such as the fifth-generation (5G) wireless, optical access networks need to be improved and enhanced. In this paper, we review emerging optical access network technologies that aim to support 5G wireless with high capacity, low latency, and low cost and power per bit. Advances in high-capacity passive optical networks (PONs), such as 100 Gbit/s PON, will be reviewed. Among the topics discussed are advanced modulation and detection techniques, digital signal processing tailored for optical access networks, and efficient mobile fronthaul techniques. We also discuss the need for coordination between RAN and PON to simplify the overall network, reduce the network latency, and improve the network cost efficiency and power efficiency.

Energy-Efficient Virtual Base Station Formation in Optical-Access-Enabled Cloud-RAN

Abstract: In recent years, the increasing traffic demand in radio access networks (RANs) has led to considerable growth in the number of base stations (BSs), posing a serious scalability issue, including the energy consumption of BSs. Optical-access-enabled Cloud-RAN (CRAN) has been recently proposed as a next-generation access network. In CRAN, the digital unit (DU) of a conventional cell site is separated from the radio unit (RU) and moved to the “cloud” (DU cloud) for centralized signal processing and management. Each DU/RU pair exchanges bandwidth-intensive digitized baseband signals through an optical access network (fronthaul). Time-wavelength division multiplexing (TWDM) passive optical network (PON) is a promising fronthaul solution due to its low energy consumption and high capacity. In this paper, we propose and leverage the concept of a virtual base station (VBS), which is dynamically formed for each cell by assigning virtualized network resources, i.e., a virtualized fronthaul link connecting the DU and RU, and virtualized functional entities performing baseband processing in DU cloud. We formulate and solve the VBS formation (VF) optimization problem using an integer linear program (ILP). We propose novel energy-saving schemes exploiting VF for both the network planning stage and traffic engineering stage. Extensive simulations show that CRAN with our proposed VF schemes achieves significant energy savings compared to traditional RAN and CRAN without VF.

ECO-FiWi: An Energy Conservation Scheme for Integrated Fiber-Wireless Access Networks

Abstract: Integrated fiber-wireless (FiWi) access networks aim at taking full advantage of the reliability and high capacity of the optical backhaul along with the flexibility, ubiquity, and cost savings of the wireless/cellular front-end to provide broadband services for both mobile and fixed users. In FiWi access networks, energy efficiency issues must be addressed in a comprehensive fashion that takes into account not only wireless front-end but also optical backhaul segments to extend the battery life of wireless devices and allow operators to reduce their OPEX, while not compromising quality of service (QoS). This paper proposes an energy conservation scheme for FiWi networks (ECO-FiWi) that jointly schedules power-saving modes of wireless stations and access points and optical network units to reduce their energy consumption. ECO-FiWi maximizes the overall network performance by leveraging TDMA to synchronize the power-saving modes and incorporate them into the dynamic bandwidth allocation (DBA) process. A comprehensive energy saving model and an M/G/1 queuing-based analysis of downstream and upstream end-to-end frame delays are presented accounting for both backhaul and front-end network segments. Analytical results show that ECO-FiWi achieves significant amounts of energy saving, while preserving upstream delay and incurring a low delay for downstream traffic.

Efficient and reliable protection mechanism in long-reach PON

Abstract: Network survivability and protection mechanisms are very important and necessary in optical networks. The long-reach passive optical network (LR-PON) proposed in this paper extends the access network to hundreds of kilometers, and it can support more optical network units by wavelength division multiplexing technology. We propose an efficient protection mechanism for the whole LR-PON. Optical encoders are used to monitor the whole network, and a network management system in the central office will initialize the protection process by monitoring the information it collects. When the network works normally, space division multiplexing technology is adopted to reduce the loss and crosstalk of signals. The designed system propagates the upstream and downstream signals in different fiber rings to mitigate the influence of Rayleigh backscattering. The proposed protection mechanism can protect the network from the multi-faults of fiber links with the designed switches. Furthermore, the loss, availability, costs, and network performance are also studied. The results obtained prove the feasibility of the proposed network. The network is costless and reliable, and it has high availability of up to 99.9992% by the protection mechanism.

Machine-to-Machine Communications Over FiWi Enhanced LTE Networks: A Power-Saving Framework and End-to-End Performance

Abstract: To cope with the unprecedented acceleration of machine-to-machine (M2M) services over cellular networks, this paper envisions a highly converged network architecture based on the integration of high-capacity and reliable Ethernet fiber-wireless (FiWi) access networks with flexible and cost-effective 4G long term evolution (LTE) technology to support M2M connectivity in an end-to-end fashion, i.e., from air interface to transport (backhaul) network. In such emerging architecture, energy efficiency must be addressed in a comprehensive way, in which both wireless front-end and optical backhaul segments are considered at the same time to maximize the battery life of battery-constrained M2M devices as well as reduce operational expenditures for network operators, while maintaining acceptable network performance. Toward this end, an end-to-end power-saving framework is introduced in this paper that devises a timeout driven discontinuous reception (DRX) mechanism for LTE-enabled M2M devices and a polling-based power-saving mechanism for optical network units (ONUs) to improve the overall energy efficiency. End-to-end performance in terms of energy saving and packet delay is analytically modeled based on a semi-Markov process for the front-end and an M/G/1 queue for the backhaul. The obtained results indicate that the device battery life is significantly prolonged by extending the DRX cycle, whereas the backhaul energy consumption is minimized by incorporating the ONU power-saving modes into the dynamic bandwidth allocation process of the optical backhaul.

IEEE 100 Gb/s EPON

Abstract: Today's optical access network technologies will run out of capacity in 4–5 years assuming the continuing exponential increases in peak bandwidth demand. This paper discusses the next generation of IEEE optical access, the 100 Gb/s Ethernet Passive Optical Network (EPON), capable of reaching bit rates of 100 Gb/s.

Cost-minimized design for TWDM-PONbased 5G mobile backhaul networks

Abstract: Dense deployment of small cells would be required to provide for high capacity and universal access to future fifth-generation (5G) mobile networks. However, this would require cost-effective and reliable backhaul connectivity between these small cells. Time and wavelength division multiplexed passive optical networks (TWDM-PONs) are considered a promising choice for this purpose. In this paper,we consider the cost-minimized design of a backhaul network for a 5G mobile system using TWDM-PON. For this, equipment and deployment costs are considered, and the design is based on satisfying network constraints such as the maximum number of subscribers per optical line terminal and themaximumnumber of subscribers per wavelength. Considering the fact that many small cell base stations are dispersed over an extensive wireless coverage, a K-means clustering-based algorithm is proposed for the optimal solution. The strategies of using multistage remote nodes and cable conduit sharing are applied to further reduce the labor cost of trenching and laying fibers. Our simulation results show that the proposed approaches can substantially reduce the backhauling cost in comparison with the traditional intuitive random-cut sectoring approach.

Networking aspects for next-generation elastic optical interfaces

Abstract: Next-generation elastic optical interfaces will support a wide range of line rates and modulation formats. Such transmission schemes enable doubling of the channel capacity at the expense of a lower reach, whereas a flexible DWDM grid supports the transport of multiple optical signals within a single frequency slot by packing them closely, thus saving spectral resources. The resulting multitude of options on the line side provides network planners the capability to derive the most suitable one for each individual path inside the network. However, planning and operational complexity should not be overlooked, since aspects such as added spectrum fragmentation can hamper the expected network improvements. This paper investigates how to obtain the best compromise between harnessing the main benefits of next-generation optical interfaces, while keeping the complexity of the underlying system at a reasonable level. In particular, we define a novel network spectral efficiency (SE) metric that enables, on one hand, to highlight the relevance of supporting a flexible grid to improve SE and, on the other hand, to demonstrate that the grid granularity can be based on coarser 50 GHz increments without major penalties. The effectiveness of this parameter has been verified by considering two reference network topologies. Finally, the paper also discusses how future optical interface technology developments will shape network design.

A flexible, ethernet fronthaul for 5th generation mobile and beyond

Abstract: Using Ethernet in the fronthaul can deliver the statistical multiplexing gains offered by the new functional splits proposed for the radio access network, but latency and delay variations are challenges that must be overcome.

Optical Traffic Grooming-Based Data Center Networks: Node Architecture and Comparison

Abstract: With data center network traffic growing significantly, power-efficient optical and hybrid optical architectures are considered as an alternate to packet switching. Typically, hybrid optical architectures use fast optical switching elements to ensure any-to-any route reachability. In this paper, an optically groomed data center network (OGDCN) framework is proposed. The proposed framework supports any-to-any route reachability without using fast optical switching elements in the network. Different components can be combined to realize an OGDCN, as described in this paper. The framework is evaluated and compared to other architectures in terms of scalability and power consumption. A particular OGDCN realization is presented and is shown to be better than other architectures in terms of power consumption. The power consumption is lower by at least 47% than the next best existing architecture proposed in the literature.

N:1 Protection design for minimizing OLTs in resilient dual-homed long-reach passive optical network

Abstract: Long-reach passive optical networks (LR-PONs) prove to be a suitable candidate for future broadband access networks. The longer reach of the feeder fiber in a LR-PON enables us to consolidate a large number of end users. The longer reach also eliminates a degree of electronic processing by eliminating the metro network and connecting the local exchanges (or the central offices) directly to a consolidated metro/core (MC) node. However, longer reach makes the feeder fiber more vulnerable to failures, and therefore, for resiliency purposes, a dual-homed architecture is proposed. For the usual case of 1 + 1 protection, the dual-homed secondary MC node would contain duplicate resources that would take over in the event of the failure of any of the individual working optical line terminals (OLTs) or the entire primary MC node in the case of a catastrophe. In this work we propose an Nl1 protection mechanism to reduce backup OLTs in a resilient dual-homed LR-PON deployment. We model the problem as an integer linear program and solve it for Irish and UK network deployments. Our results show that the percentage of backup OLTs can be reduced by 6 times for Ireland and by 4 times for the UK compared to a 1 + 1 protection deployment scenario.

NG-PON2 Transmission Convergence Layer: A Tutorial

Abstract: The first family of multi-wavelength PON systems, 40-gigabit-capable capable passive optical networks (NG-PON2), has been specified by the Telecommunication Standardization Sector of the International Telecommunications Union (ITU-T). This tutorial, which is based on the author's ECOC'2015 presentation on the topic, offers a comprehensive review of the NG-PON2 transmission convergence layer specification, and is addressed to a wide range of readers who are active in the field of optical communications.

Performance benefits of optical circuit switches for large-scale dragonfly networks

Abstract: We propose Optical Circuit Switching for dynamically creating reconfigurable partitions in large-scale systems with Dragonfly networks. Up to 2x execution-time improvement is demonstrated for global traffic patterns in a >13,000-node system using a production-grade network simulator.

Experimental demonstration of remote unified control for OpenFlow-based software-defined optical access networks

Abstract: Passive optical network (PON) has attracted much attention by the emergence of high-bitrate video-centric applications over the Internet in the access side. In the current commercial PON, the configuration of optical line termination equipment is needed to modify through network management system manually and periodically in the local areas. The traffic flow of different users lacks dynamic control and intelligent schedule. In this paper, we propose and implement a novel software-defined optical access network (SDOAN) architecture for remote unified control based on OpenFlow-enabled PON. Based on the proposed architecture, a service-aware flow scheduling strategy is introduced to flexibly and efficiently allocate the network bandwidth resources and detect the status of network flows in real time. The SDOAN can enhance the resource utilization and QoS guarantee of each user effectively through unified control manner, and reduce the operating expense by remote interaction and operation. We have designed and verified experimentally SDOAN on our test bed with OpenFlow-enabled OLTs. The overall feasibility and efficiency of the proposed architecture are also experimentally demonstrated and compared with interleaved polling with adaptive cycle time strategy in terms of resource occupation rate and average delay.

Network planning for 802.11ad and MT-MAC 60 GHz fiber-wireless gigabit wireless local area networks over passive optical networks

Abstract: We present a study concerning the network planning of 60 GHz gigabit wireless local area networks (WLANs) over existing passive optical network (PON) infrastructures. Two fiber-wireless configurations for gigabit WLAN network formations are investigated: i) the Radio & Fiber (RF and ii) the Radio-over-Fiber (RoF) paradigm that employs several remote access units operating under the medium-transparent MAC (MT-MAC) protocol, hence termed as the MT-MACover- PON approach. Simulation-based throughput and delay results are obtained for both network scenarios, revealing the dependence of the 60 GHz enterprise network performance on several network-planning parameters such as load, traffic shape, number of optical wavelengths in the backhaul, and optical backhaul fiber length, highlighting in each case the prevailing architecture. Based on the respective findings we also study a hybrid multitier architecture, termed the GPON-plus-MT-MAC approach, that fuses the abilities of both the RoF and R&F architectures in order to optimally combine their properties and set a framework for next-generation 60 Ghz fiber-wireless networks.

First Demonstration of Virtual Transport Network Services With Multi-layer Protection Schemes over Flexi-grid Optical Networks

Abstract: Based on the virtualization technique in optical networks, virtual transport network services (VTNS) has been introduced as a new kind of service in transport networks. With VTNS, transport providers are able to provide their customers entire virtual topologies instead of traditional end-to-end connections. This letter analyzes the new characteristics (i.e., multiple operators, diversified services) aiming at the survivability problem in virtualized optical transport networks, and proposes three novel protection schemes for VTNS against the new features. For the first time, VTNS with the proposed protection schemes are demonstrated on the flexi-grid optical networks testbed with commercial optical transport equipments. Additionally, the performances of the proposed protection schemes have been evaluated via simulations.

Demonstration of dynamic traffic allocation in an SDN-enabled metropolitan optical network test-bed

Abstract: Elastic optical networking (EON) is a viable solution to accomplish future capacity requirements of network operators. EON relies on reconfigurable optical add/drop multiplexers (ROADMs) capable of routing arbitrary channel bandwidths usually based on wavelength selective switches (WSSs). In this context, control-plane implementations (including signaling latency) and configuration times of WSSs are the two major contributors to delay the creation of label-switched paths (LSPs) in highly dynamic traffic scenarios. In this paper, we first show the optical data-plane implementation and operation in a metropolitan optical network. Then, we propose and experimentally demonstrate techniques to exploit the advantages of the centralized network's control logic intrinsic in SDN. Results prove the suitability of our proposals to enable fast LSP establishment in scenarios with high dynamic traffic.

Tactile internet capable passive optical LAN for healthcare

Abstract: We present the underlying communications network that achieves rapid delivery of control/steering/sensor information in Tactile Internet capable healthcare facilities. Exploiting passive optical LANs with TWDM and predictive DBA, an end-to-end latency of 200µs is achieved.

Migration strategies for FTTx solutions based on active optical networks

Abstract: AON, one of the most deployed fiber access solutions in Europe, needs to be upgraded in order to satisfy the ever growing bandwidth demand driven by new applications and services. Meanwhile, network providers want to reduce both capital expenditures and operational expenditures to ensure that there is profit coming from their investments. This article proposes several migration strategies for AON from the data plane, topology, and control plane perspectives, and investigates their impact on the total cost of ownership

Economic aspects of free space optics as an alternative broadband network connection for the last mile

Abstract: In order to provide a powerful and fast communications infrastructure to end customers and private households, optical fiber connections are on the increase to close the last mile gap. However, this infrastructure expansion is slow and expensive. In contrast to optical fiber, Free Space Optics (FSO) has nowadays become a well-established technology for the last mile access. This contribution gives an overview of commercial FSO systems and investigates their integration into existing optical fiber networks from an economic point of view. Different optical fiber projects for the last mile, including fiber-to-the-home (FTTH) projects and business park connections, were investigated and compared with FSO systems. The results of the study show, that FSO is a viable and cost-effective alternative to fiber optics. Furthermore, a concept of a point-to-multipoint (P2MP) Optical Wireless (OW) system for a flexible broadband network connection in a settlement area is proposed.

Demonstration of SDN enabled dynamically reconfigurable high capacity optical access for converged services

Abstract: A dynamically reconfigurable TDM-DWDM PON for converged multi-services at the physical layer (10G, 100G and wireless fronthaul) has been demonstrated for the first time implementing end-to-end SDN management of the access and core network elements.

A multi-OLTs and virtual passive optical network for hybrid network

Abstract: Passive optical network (PON) has been widely applied in access network benefitting from its large bandwidth and low-cost passive components that consumes less power, and transport different type of services in hybrid networks. In this paper, we propose a multi-OLT-based virtual PON (MV-PON) system with a dynamic bandwidth allocation (DBA) algorithm. According to simulation results, the proposed system effectively reduces the complexity for data packet processing in the OLT of multiple services.

OPSquare: Assessment of a novel flat optical data center network architecture under realistic data center traffic

Abstract: The performances of OPSquare flat data-center network based on flow-controlled optical switches are investigated. Results show <1E-6 packet loss and <2μs end-to-end latency for 0.3 load when scaling to 40960 servers with 32×32 optical switches.

Power-aware virtual optical network provisioning in flexible bandwidth optical networks [Invited]

Abstract: Considering the virtual network infrastructure as a service, optical network virtualization can facilitate the physical infrastructure sharing among different clients and applications that require optical network resources. Obviously, mapping multiple virtual network infrastructures onto the same physical network infrastructure is one of the greatest challenges related to optical network virtualization in flexible bandwidth optical networks. In order to efficiently address the virtual optical network (VON) provisioning problem, we can first obtain the virtual links' order and the virtual nodes' order based on their characteristics, such as the bandwidth requirement on virtual links and computing resources on virtual nodes. We then preconfigure the primary and backup paths for all node-pairs in the physical optical network, and the auxiliary graph is constructed by preconfiguring primary and backup paths. Two VON mapping approaches that include the power-aware virtual-links mapping (PVLM) approach and the power-aware virtual-nodes mapping (PVNM) approach are developed to reduce power consumption for a given set of VONs in flexible bandwidth optical networks with the distributed data centers. Simulation results show that our proposed PVLM approach can greatly reduce power consumption and save spectrum resources compared to the PVNM approach for the single-line rate and the mixed-line rate in flexible bandwidth optical networks with the distributed data centers.

Resilient backhaul network design using hybrid radio/free-space optical technology

Abstract: The radio-frequency (RF) technology is a scalable solution for the backhaul planning. However, its performance is limited in terms of data rate and latency. Free Space Optical (FSO) backhaul, on the other hand, offers a higher data rate but is sensitive to weather conditions. To combine the advantages of RF and FSO backhauls, this paper proposes a cost-efficient backhaul network using the hybrid RF/FSO technology. To ensure a resilient backhaul, the paper imposes a given degree of redundancy by connecting each node through K link-disjoint paths so as to cope with potential link failures. Hence, the network planning problem considered in this paper is the one of minimizing the total deployment cost by choosing the appropriate link type, i.e., either hybrid RF/FSO or optical fiber (OF), between each couple of base-stations while guaranteeing K link-disjoint connections, a data rate target, and a reliability threshold. The paper solves the problem using graph theory techniques. It reformulates the problem as a maximum weight clique problem in the planning graph, under a specified realistic assumption about the cost of OF and hybrid RF/FSO links. Simulation results show the cost of the different planning and suggest that the proposed heuristic solution has a close-to-optimal performance for a significant gain in computation complexity.

Integrated SDN/NFV orchestration for the dynamic deployment of mobile virtual backhaul networks over a multi-layer (Packet/Optical) aggregation infrastructure

Abstract: We propose and experimentally validate an SDN/NFV orchestrator to dynamically create virtual backhaul tenants over a multi-layer (packet/optical) aggregation network and deploy virtual network functions (vEPC and vSDN controller) to better adapt MNO's capacity increase.

Stand-Alone and Cooperative Deep Sleep for Battery-Driven Optical Network Unit

Abstract: In the era of the Internet of Things (IoT), the access network should provide Internet connectivity to huge numbers of wireless sensor nodes that are collecting data. For most sensor nodes, the macro cells of cellular networks provide cost-effective connectivity. However, covering the remaining nodes, which are either in the out-of-service state or have short-range wireless interfaces only, is a difficult issue. For example, when deploying small cells densely to provide fuller node coverage, the cost of the small cells should be well considered. From the perspective of economy, small cells that use the passive optical network (PON) and moderately priced wireless interfaces, called fiber-wireless (Fi-Wi) in this paper, seem the most promising candidates. However, the flexibility in Fi-Wi system deployment is strictly constrained by the need for a stable power source. Because most of the PON systems have been developed for fiber to the home (FTTH), the gateway node on the customer premise continuously consumes power and thus requires a stable power source. Therefore, the key issue is how to reduce the power consumption of the Fi-Wi gateway node drastically enough to run continuously with only battery and/or solar power. Additionally, the power-saving approach must meet the requirements of the IoT applications at the same time. We focus on the deep sleep approach, which turns off almost all the components, with significant power savings at the cost of a drop in quality of service (QoS). This paper proposes methods to control the deep sleep while assuring successful packet reception.

Performance Analysis of DPSK-OCDMA System for Optical Access Network

Abstract: Abstract In this research, the performance of optical code division multiple access (OCDMA) using differential phase shift keying (DPSK) has been compared with OCDMA On-Off Keying (OOK). This comparison took place in terms of bit error rate (BER) and receiver power where two bit rates (155 Mbps and 622 Mbps) have been used for this analysis. Using of OptiSystem 7.0 simulation, comparing eye diagram and optical spectrum alongside with BER and Rx power. It is found that OCDMA-DPSK performs better in comparison to OCDMA-OOK. The performance analysis also provides parameter for designing and development of an OCDMA system for optical access network using DPSK.

Internet of things with optical connectivity, networking, and beyond

Abstract: Optical technologies play an important role in the Internet of Things networks, including providing high bandwidth connectivity, intelligent networking, and high sensitivity multi-phenomena sensing and imaging. Related optical technologies and IoT applications are discussed.

High speed OFDM-CDMA optical access network.

Abstract: We demonstrate the feasibility of a 16 × 3.75 Gb/s (60 Gb/s aggregate) Orthogonal frequency division multiplexing-code division multiple access passive optical network for next-generation access applications. 3.75 Gb/s PON channel transmission over 25 km single-mode fiber shows 0.1 dB dispersion and 0.9 dB crosstalk penalties. Advantages of the system include high capacity, enhanced spectral efficiency, coding gain, and networking functions such as increased security and single-wavelength operation.