Dynamic Wavelength Allocation Research Articles

Architecture for low-cost and highly flexible metro-access networks using SOA-based OADM nodes and digital subcarrier multiplexing with power loading.

Metro-access networks exploiting wavelength division multiplexing (WDM) to cope with the ever-growing bandwidth demands are sensitive to cost and need to be fast-configurable to meet the requirements of many new network services. Optical add-drop multiplexers (OADMs) are a key component in enabling fast dynamic wavelength allocation and optimization. In this Letter, we propose and demonstrate, to our knowledge, a novel architecture for high-performance metro-access networks that utilizes semiconductor optical amplifier (SOA)-based OADM nodes, digital subcarrier multiplexing (DSCM), low-cost direct detection receivers, and power loading techniques, which makes the designed metro-access network cost-effective, fast reconfigurable, and flexible for bandwidth allocation on demand. Through a proof-of-concept experiment, we have successfully demonstrated a prototype horseshoe optical network consisting of up to four SOA-based OADM nodes at 40 Gb/s per wavelength channel by leveraging the proposed scheme. The flexible bandwidth allocation and dynamic add and drop operations have also been achieved in an emulated WDM optical network. All results indicate the great scalability and flexibility of the proposed architecture.

Evaluation of resource efficiencies for the non-symmetric dynamic wavelength allocation method applied in the P2MP WDM-PON network design

At present days, metropolitan and access communication networks are markedly developing utilizing a variety of technologies. Their bearer communication infrastructures will be mostly exploiting the optical transmission medium where wavelength division multiplexing techniques will play a key role. Wavelength-Division Multiplexed Passive Optical Networks (WDM-PON) attract considerable attention for the next generation optical metropolitan and access networked systems. Simultaneously, the utilization of common optical network resources in wavelength domains will be more important. The main purpose of this paper is presented by the evaluation of resource efficiencies for the non-symmetric dynamic wavelength allocation method applied in the WDM-PON network design with aconventional topology. This contribution introduces a novel non-symmetric Dynamic Wavelength Allocation (DWA) method for a selected network design with the utilization only passive optical splitters in remote nodes. This novel wavelength allocation method is oriented on minimizing anumber of working wavelengths that will be used for compliance of customers’ requests for data transmitting in the common point-to-multipoint WDM–PON network design. For evaluation of wavelength scheduling, a simulation model related to the conventional WDM-PON network design is realized in the MATLAB programming environment is presented with results. Finally, different traffic loading scenarios are determined and, subsequently, resource efficiencies of the presented non-symmetric DWA method are evaluated from aviewpoint of application in future WDM-PON network designs.

Protection Schemes in HPON Networks Based on the PWFBA Algorithm.

In this paper, possibilities for network traffic protection in future hybrid passive optical networks are presented, and reasons for realizing and utilizing advanced network traffic protection schemes for various network traffic classes in these networks are analyzed. Next, principles of the Prediction-based Fair Wavelength and Bandwidth Allocation (PFWBA) algorithm are introduced in detail, focusing on the Prediction-based Fair Excessive Bandwidth Reallocation (PFEBR) algorithm with the Early Dynamic Bandwidth Allocation (E-DBA) mechanism and subsequent Dynamic Wavelength Allocation (DWA) scheme. For analyzing various wavelength allocation possibilities in Hybrid Passive Optical Networks (HPON) networks, a simulation program with the enhancement of the PFWBA algorithm is realized. Finally, a comparison of different methods of the wavelength allocation in conjunction with specific network traffic classes is executed for future HPON networks with considered protection schemes. Subsequently, three methods are presented from the viewpoint of HPON network traffic protection possibilities, including a new approach for the wavelength allocation based on network traffic protection assumptions.

Load adaptive merging algorithm for multi-tenant PON environments

Wavelength division multiplexing\ ime division multiplexing passive optical network (WDM/TDM-PON) is the attractive candidate for PON bandwidth sharing among multiple service providers, featuring massive bandwidth and longer reach. This infrastructure reduces the overall cost of the Fiber-to-the-premises (FTTP) services and offers relatively lower tariffs for the end customers. The dynamic bandwidth and wavelength allocation (DBWA) process in such PON networks ensure the fair sharing of the available bandwidth resources among the virtual network operators (vNOs). The earlier reported DBWA schemes with multiple vNOs have not efficiently utilized the unused and residual upstream bandwidth. This study presents a novel load adaptive merging algorithm (LAMA) for converting various individual virtual bandwidth maps(vBWmaps) into a single physical bandwidth map (phyBWMap). The LAMA scheme modifies the existing strict priority scheme called the Priority-Based Merging Algorithm (PBMA) scheme and improves the performance of the merging engine by allocating the phyBWMap in a load adaptive manner to the vNOs in the multi-tenant PON architecture. The proposed algorithm is compared with PBMA in terms of throughput efficiency, upstream delay, and capacity utilization under self-similar and Poison traffic scenarios. The results show that the proposed scheme offers higher bandwidth utilization resulting in increased throughput with lower upstream delays in the multi-tenant PON environment.

Self-Adaptive Resource-Allocation Scheme Combining Traffic Prediction With User Satisfaction in Multi-Wavelength VPON

In this paper, a self-adaptive resource-allocation scheme combining traffic prediction with user satisfaction is firstly established in multi-wavelength VPON. Among VPONs, by proposing a (wavelength utility)-based dynamic wavelength allocation algorithm, the optimal allocation of wavelengths can be achieved. In a VPON: under condition that the total requested bandwidth is larger than the total bandwidth, by introducing a bandwidth constraint factor <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϵ</i> , the maximum amount of bandwidth granted for high-priority service can be limited, and the “starvation” problem of low-priority service can be prevented. By solving the user satisfaction model, not only the optimal allocation of low-priority service can be obtained, but also the comprehensive user satisfaction is maximized. Under condition that the total requested bandwidth is smaller than the total bandwidth, by combining an ANN prediction model with a user satisfaction model, a bandwidth allocation model based on traffic prediction and user satisfaction is created. By this model, not only the resource utilization is improved but also the transmission delay is reduced. At the same time, user satisfaction is maximized. By adjudicating on the set judgment condition, the self-adaptive function of control system for the above two conditions is implemented. By simulation, the effectiveness of the proposed scheme is demonstrated.

A Software-Defined Programmable Testbed for Beyond 5G Optical-Wireless Experimentation at City-Scale

Wireless traffic will significantly increase in next-generation networks. Therefore, there is a need for novel optical network front-/mid-/backhaul (x-haul) architectures that can deliver ultra-high bandwidth and ultra-low-latency services to wireless and edge cloud systems, as well as support various cloud radio access network (C-RAN) architectures. Designing and evaluating such architectures requires large-scale experimental platforms. In this article, we present the design and implementation of a unique, remotely accessible, disaggregated, and programmable optical network as the key component of the city-scale PAWR COSMOS advanced wireless testbed. We discuss the design and implementation of a dedicated multi-functional Ryu software-defined networking (SDN) controller for the testbed's optical network wavelength channel assignment and topology reconfiguration. We present an example use of the SDN controller for monitoring and automated measurement of the wavelength-dependent amplifier gain in deployed reconfigurable optical add/drop mul-tiplexer (ROADM) units. We also demonstrate a pilot experiment focusing on a wireless handover scheme for C-RAN architectures in the COSMOS testbed, where high traffic volume can be supported by dynamic wavelength allocation via optical switching in the fronthaul. The field-deployed testbed and SDN controller can be used by the research community to push the envelope in the area of optical networks for beyond 5G and 6G.

An Effective Evaluation of Wavelength Scheduling for Various WDM-PON Network Designs with Traffic Protection Provision

Recently, metropolitan and access communication networks have markedly developed by utilizing a variety of technologies. Their bearer communication infrastructures will be mostly exploiting the optical transmission medium where wavelength division multiplexing techniques will play an important role. This contribution discusses the symmetric sharing of common optical network resources in wavelength and time domains. Wavelength-Division Multiplexed Passive Optical Networks (WDM-PON) attract considerable attention regarding the next generation of optical metropolitan and access networks. The main purpose of this contribution is presented by the analysis of possible scheduling of wavelengths for our novel hybrid network topologies considered for WDM-PON networks. This contribution briefly deploys adequate Dynamic Wavelength Allocation (DWA) algorithms for selected WDM-PON network designs with the provision of traffic protection when only passive optical components in remote nodes are utilized. The main part of this study is focused on the use of wavelength scheduling methods for selected WDM-PON network designs. For evaluation of offline and online wavelength scheduling for novel hybrid network topologies, a simulation model realized in the Matlab programming environment allows to analyze interactions between various metropolitan and access parts in the Optical Distribution Network (ODN) related to advanced WDM-PON network designs. Finally, wavelength scheduling methods are compared from a viewpoint of utilization in advanced WDM-PON networks designs.

Bin-packing based offline dynamic bandwidth and wavelength allocation algorithms for power efficiency in Super-PON

Enduring the rapidly growing demand for high data rates is the main challenge for the current network providers. Super passive optical network (Super-PON), a prominent next generation Ethernet PON (NG-EPON) candidate, can suffice this exponentially increasing data rate requirements. However, to appease such requirements, it employs many transceivers and increases the power-consumption of the network. In this work, we focus on reducing the carbon footprint of Super-PON and propose power-efficient dynamic bandwidth and wavelength allocation (DBWA) algorithms, namely best fit bin-packing sleep mode aware (BF-SMA) and updated BF-SMA (UBF-SMA). The proposed algorithms use SMA for bandwidth scheduling and different bin-packing techniques for wavelength allocation. In bin-packing, the number of available wavelengths and their efficient allocation is based on the network load. For restricting the number of available wavelengths, we can switch off the non-essential transceivers at the OLT, which also helps in maximizing the wavelength utilization and increasing the power efficiency. The simulation results show that in comparison to the state-of-the-art DBWA algorithms, the proposed algorithms improve the power efficiency and reduce the average delay of a Super-PON system. Furthermore, we use Jain’s fairness index to validate the fairness of the proposed DBWA algorithms.

Bin-Packing-Based Online Dynamic Bandwidth and Wavelength Allocation Algorithm in Super-PON

Super passive optical network (Super-PON) is a next-generation Ethernet PON (NG-EPON) candidate that is envisaged to provide high data rate and low latency. For NG-EPON, there are two types of algorithms that manages bandwidth and wavelength scheduling, namely offline and online. The latter method is more scalable and efficient than the former method. Several online algorithms exist that propose schemes to manage wavelength and bandwidth scheduling. However, these algorithms lack in efficient wavelength utilization and switching. In this work, we propose a novel online bin-packing based dynamic bandwidth and wavelength allocation (DBWA) algorithm for Super-PON, namely updated best fit bin-packing (UBF-BP). This algorithm limits the wavelength switching per cycle, and uses the modified version of best fit bin-packing (BF-BP) technique for optimal wavelength allocation. Simulation results show that the proposed DBWA algorithm has a low complexity and overcomes the inefficiencies of wavelength utilization and switching. This results in lower network delay and higher channel utilization than the state-of-the-art DBWA. Furthermore, to verify the correctness of the proposed algorithm, we propose an analytical model and validate these simulation results with the analytical results.

Dynamic wavelength and bandwidth allocation for supporting diverse customers and prioritized traffic in NG-PON2 networks

Resource allocation is a fundamental task in any PON and it is necessary to have an efficient scheme that reduces delay, maximizes bandwidth usage, and minimizes the resource wastage. A variety of dynamic bandwidth allocation (DBA) and dynamic wavelength and bandwidth allocation (DWBA) algorithms have been proposed which are based on different PONs (e.g., EPON, GPON, XG-PON, 10G EPON, etc.). But to our knowledge, no DWBA scheme for NG-PON2 system, with diverse customers and prioritized traffic, has been proposed yet. In this work, this problem is addressed and five different dynamic wavelength and bandwidth allocation (DWBA) schemes are proposed. First, mixed integer linear programming (MILP) models are developed to minimize the total delay of the high-priority data. Due to the MILP’s high computational complexity, heuristic algorithms are developed based on the MILP model insights. The five heuristic algorithms are: No Block-Split Heuristic (NBH), Equal Block-Split Heuristic (EBH), Priority-Based No Block-Split Heuristic (P-NBH), Priority-Based Equal Block-Split Heuristic (P-EBH), and Priority-Based Decider Block-Split Heuristic (P-DBH). Six priority classes of requests are introduced with the goal of minimizing the total delay for the high-priority data and to lessen the bandwidth wastage of the system. Finally, experiments for the performance evaluation of the five DWBA schemes are conducted. The results indicate that P-NBH, P-EBH, P-DBH schemes show a 47.63% less delay and 30% of less bandwidth wastage on average for the highest priority data transmission than the schemes without priority support (NBH and EBH). Among these five schemes, NBH method has the highest delay, whereas EBH and P-EBH waste more bandwidth than the other schemes. P-DBH is the most efficient among the five, because this scheme offers the lowest delay for high-priority data and the minimum bandwidth wastage for lower priority ones.

Flexible coherent UDWDM-PON with dynamic user allocation based on limited-tunability lasers

Coherent wavelength division multiplexing (WDM) technologies have leveraged the optical communication systems in core networks, increasing the fiber capacity by transmission with advanced modulation formats and mitigation of impairments with digital signal processing. However, these solutions are too expensive for access networks, where cost, power budget, and footprint are limited. Hence, the key technology will be developing low-cost coherent transceivers providing an excellent selectivity and giving high sensitivity, which allows high splitting ratios. This paper reports an experimental design of a low-cost coherent ultra-dense WDM passive optical network (UDWDM-PON) with 6.25 GHz channel spacing. The users’ optical network unit (ONU) is built employing coherent transceivers with two paired low-cost distributed feedback (DFB) lasers, one as the local oscillator and another as the transmitter, offering simplicity and low-cost hardware; likewise, the optical line terminal (OLT) at the central office can profit from the same design. The ONU DFB lasers have wavelengths with limited thermal tunability, controlled by a thermo-electric cooler, which is used to allocate the wavelengths. A medium access control (MAC) at the OLT manages the spectrum channel allocation for ONUs, demanding connection when activation is requested: the OLT furnishes an optical carrier wavelength for the ONU to obtain connection by a control algorithm, assigning a down-channel and another paired up-channel assigned to the ONU DFB transmitter. The MAC can reassign the channels because of interference or collision in a dynamic wavelength allocation. Measures in an activation process and in channel reassignment have been performed in environmental conditions, including control signals and the physical parameters of DFB lasers, demonstrating the practical viability of the PON scaling from 32 up to 256 wavelength channels.

ITU TWDM-PON module for ns-3

Optical fiber access systems are one of the driving forces behind the success of the Internet. Time- and wavelength-division multiplexing passive optical network (TWDM-PON) is regarded as the key technology for future Internet access networks. In this paper, we propose an ITU TWDM-PON module for the ns-3 network simulator and describe its concept and design specifications. The proposed module is developed based on the XG-PON module for ns-3. It can simulate G.989 standard-compliant data packet transmission in the upstream and downstream directions using multiple wavelength channels. It enables us to evaluate the performance issues that arise with the TWDM-PON development, including various dynamic bandwidth allocation and dynamic wavelength allocation algorithms. The proposed module is expected to become a good platform for studying future access networks composed of TWDM-PON and mobile networks by enabling us to simulate dynamic wavelength and bandwidth allocation.

A learning algorithm for TWDM-PON’ DWBA with 5G fronthaul networks

Abstract Time and wavelength-division multiplexed passive optical network (TWDM-PON) is expected to be the fronthaul networks of 5G, which requires low latency and large bandwidth. In this paper, we propose a Q-learning based dynamic wavelength and bandwidth allocation (DWBA) algorithm for TWDM-PON. Simulation results show that the proposed DWBA algorithm can reduce the number of active channels by 40% and provide larger bandwidth with same wavelength number in comparation with the existing algorithms while satisfying the latency requirement of 5G fronthaul networks.

Research of Algorithms used for Routing and Assigning Wavelength in WDM Networks

The telecommunications department is the most difficult in today's communication offering the highest amount of bandwidth. With the finest prototypes and test rigs to form optical WDM technology, many companies have appeared for a particular link request, a wavelength and a path must be allocated in the WDM network. Routing and Wavelength Assignment (RWA) problem is called the assignment of a wavelength and a path to the link request, with accessible resources. The aim of this article is to analyze the algorithms for any WDM networks for efficient wavelength assignment routing protocols. As a researcher, we plan to suggest a comprehensive literature study for the development of a new algorithm for efficient allocation and appropriate wavelength usage and the routing of data packets from source to destination to overcome all failures. Before allocation, we use simulations and analyze optic fiber communication methods, various losses depending on dynamic wavelength allocation with minimum and maximum.

Efficient T-CONT-Agnostic Bandwidth and Wavelength Allocation for NG-PON2

Dynamic bandwidth and wavelength allocation are used to demonstrate high quality of service (QoS) in time wavelength-division multiplexed–passive optical networks (TWDM-PONs). Both bandwidth and wavelength assignment are performed on the basis of transmission containers (T-CONTs) and therefore by means of upstream service priority traffic flows. Our medium access control (MAC) protocol therefore ensures consistency in processing alike classes of service across all optical network units (ONUs) in agreement with their QoS figures. For evaluation of the MAC protocol performance, a simulator has been implemented in OPNET featuring a 40 km, 40 Gbps TWDM-PON with four stacked wavelengths at 10 Gbps each and 256 ONUs. Simulation results have confirmed the efficiency of allocating bandwidth to each wavelength and the significant increase of network traffic flow due to adaptive polling from 9.04 to 9.74 Gbps. The benefit of T-CONT-centric allocation has also been measured with respect to packet delay and queue occupancy, achieving low packet delay across all T-CONTs. Therefore, improved NG-PON2 performance and greater efficiency are obtained in this first demonstration of T-CONTs allocated to both wavelength and time.

TWDM-PON中支持区分服务的节能动态波长带宽分配算法

TWDM-PON中支持区分服务的节能动态波长带宽分配算法

Adaptive dynamic wavelength and bandwidth allocation algorithm based on error-back-propagation neural network prediction

With the emergence of new services such as high-definition video, cloud computing and virtual reality, Wavelength Division Multiplexing/Time Division Multiplexing-Passive Optical Network (WDM/TDM-PON) has become a key technology for future access network. The development of Software Defined Networking (SDN) and machine learning also brings new opportunities to the flexibility of WDM/TDM-PON. In this paper, an Adaptive Dynamic Bandwidth Allocation algorithm based on error-back-propagation Neural Network Prediction (ADBA-NNP) was proposed to reduce the Round-trip-time (RTT) delay in the bandwidth-scheduling period. A Dynamic Wavelength Allocation (DWA) algorithm and a novel architecture of WDM/TDM-PON was proposed to simple the multi-carrier source. The experimental results validated that the proposed algorithm could dynamically allocate wavelengths under multi-carrier at 12.5G intervals. Compared with the traditional algorithms, the proposed algorithm could reduce the transmission delay by 25%.

Dynamic Wavelength Allocation and Analytical Model for Flow Assignment in Optical Packet and Path Integrated Networks

A hybrid optical architecture combining path (circuit) and packet switching can be a good candidate for future optical networks because it exploits the best of both worlds. In this paper, we present a control framework called the Dynamic Optical Wavelength and Flow Allocation Framework (DOWFAF), which can dynamically change the ratio of path and packet wavelengths and the flow size threshold in the hybrid path–packet integrated networks in order to balance the utilization of path and packet subnetworks and maximize the ratio of large flows benefiting from the path switching. We propose an analytical model for calculating the flow size threshold and a feedback control for estimating the wavelength allocation ratio for varying traffic. DOWFAF can be implemented by software-defined networking, which is getting a lot of attention recently. We show that DOWFAF can greatly increase the goodput of large Transmission Control Protocol (TCP) flows for a wide range of traffic, while decreasing the cost and the power consumption.

Dynamic Bandwidth and Wavelength Allocation Scheme for Next-Generation Wavelength-Agile EPON

Recently, the IEEE 802.3 Ethernet Working Group has classified three architectures for the next-generation Ethernet passive optical network (NG-EPON). They are called single-scheduling domain (SSD) PON, multi-scheduling domain (MSD) PON, and wavelength-agile (WA) PON, and they differ based on how a group of optical network units (ONUs) share a wavelength. Existing dynamic bandwidth and wavelength allocation (DBWA) schemes for conventional EPON can be applied to MSD-PON and SSD-PON, but not WA-PON. This is because WA-PON is a new architecture with full flexibility where a flexible number of wavelengths can be assigned to one ONU, and multiple ONUs can transmit at the same time. In this work, we develop a mathematical model and a novel DBWA scheme for transmission scheduling in WA-PON. However, as WA-PON incurs penalties in terms of delay and power consumption when an ONU activates its transmissions on new wavelengths, a trade-off between energy saving and data-transfer latency reduction needs to be carefully addressed when performing transmission scheduling. So, we develop a power-consumption model and modify the proposed DBWA scheme to enhance the energy efficiency of WA-PON. Finally, we conduct simulation experiments for performance evaluation of the three PON architectures in terms of latency and packet loss ratio. We quantitatively investigate the influence of various parameters, such as the number of ONU transceivers and ONU buffer size, on WA-PON latency and packet loss ratio, and we evaluate the energy efficiency gain of the modified DBWA scheme.

Energy efficient flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network with pay as you grow deployment

A flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network architecture that allows dual rate signals to be sent at 1 and 10 Gbps to each optical networking unit depending upon the traffic load is proposed. The proposed design allows dynamic wavelength allocation with pay-as-you-grow deployment capability. This architecture is capable of providing up to 40 Gbps of equal data rates to all optical distribution networks (ODNs) and up to 70 Gbps of a asymmetrical data rate to the specific ODN. The proposed design handles broadcasting capability with simultaneous point-to-point transmission, which further reduces energy consumption. In this architecture, each module sends a wavelength to each ODN, thus making the architecture fully flexible; this flexibility allows network providers to use only required OLT components and switch off others. The design is also reliable to any module or TRx failure and provides services without any service disruption. Dynamic wavelength allocation and pay-as-you-grow deployment support network extensibility and bandwidth scalability to handle future generation access networks.