Performance evaluation of multi-stratum resources optimization with network functions virtualization for cloud-based radio over optical fiber networks

Radio access network (RAN) cost savings are expected in future cloud RAN (C-RAN). In contrast to traditional distributed RAN architectures, in C-RAN, remote radio heads (RRHs) from different sites can share baseband processing resources from virtualized baseband unit pools placed in a few central locations (COs). Due to the stringent requirements of the several interfaces needed in C-RAN, optical networks have been proposed to support C-RAN. One of the key elements that needs to be considered are optical transponders. Specifically, sliceable bandwidthvariable transponders (SBVTs) have recently shown many advantages for core optical transport networks. In this paper, we study the connectivity requirements of C-RAN applications and conclude that dynamicity, fine granularity, and elasticity are needed. However, there is no SBVT implementation that supports those requirements, and thus, we propose and assess an SBVTarchitecture based on dynamic optical arbitrary generation/measurement. We consider different long-term evolution-advanced configurations and study the impact of the centralization level in terms of the capital expense and operating expense. An optimization problem is modeled to decide which COs should be equipped and which equipment, including transponders, needs to be installed. The results show noticeable cost savings from installing the proposed SBVTs compared to installing fixed transponders. Finally, compared to the maximum centralization level, remarkable cost savings are shown when a lower level of centralization is considered.

In order to implement the accurate transmission of relay protection signals in fiber optic communication networks, it is necessary to carry out the channel equalization configuration of fiber optic communication networks and the adaptive forwarding control processing of relay protection signals, put forward a method of accurate transmission of relay protection signals in fiber optic communication networks based on the suppression of time-varying multipath fading and adaptive beam formation, construct the relay channel equalization model of fiber optic communication networks, and adopt the fiber optic baud interval equalization technique to carry out the equalization design of relay communication transmission links in fiber optic communication networks. Equalization technology is used for the equalization design of relay communication transmission link in fiber optic communication network. For the time-varying multipath attenuation of communication channel, the multipath suppression is carried out by the successive tapping processing method of the electric signal, the optimal baud spacing of relay protection signals is sampled according to the time-varying multipath fading loss of the channel, and the multipath fading suppression is used to compensate the signals and filter the interferences of the fiber optic network communication channel and achieve the accurate transmission method of relay protection signals in fiber optic communication network. Adaptive beam forming and accurate transmission of relay protection signals are realized. The simulation results show that the accuracy of relay protection signal transmission in fiber optic communication network is better, the anti-interference ability is stronger, and the channel balance is better.

Ubiquitous data center optical interconnection is a promising scenario to meet the high burstiness and high-bandwidth requirements of services in terms of the user-access-oriented interconnection between user and data center, inter-data- center, and intra-data-center interconnection. However, in the current mode of operation, the control of the data center and optical network is separately deployed. Enabling even limited interworking among these separated control systems does not provide a mechanism to exchange resource information and enhance the high-level performance requirement of applications. Our previous work implemented cross-stratum optimization of optical network and application strata resources inter-data-center, which allows the accommodation of data center services. In view of this, this study extends to the ubiquitous data center optical interconnection scenario. This article presents a novel SUDOI architecture aimed at extensive user access from the perspective of heterogeneous cross-stratum and multi-layer networking modes. SUDOI can enable cross-stratum optimization of application and optical network stratum resources, and enhance multiple- layer resource integration in the ubiquitous data center optical interconnection. The functional modules of SUDOI architecture, including the core elements of various controllers, are described in detail. The cooperation procedure in user-access-oriented interconnection, multiple- layer resource integration inter-data-center, and intra-data-center service modes is investigated. The feasibility and efficiency of the proposed architecture are also experimentally demonstrated on our OaaS testbed with OpenFlow-enabled optical nodes, and compared to the CSO scheme in terms of blocking probability and resource occupation rate. Numerical results are given and analyzed based on the testbed. Some future discussion and exploration issues are presented in the conclusion.

<p> Traditionally, wireless networks and optical fiber Networks are independent of each other. Wireless networks are designed to meet specific service requirements, while dealing with weak physical transmission, and maximize system resources to ensure cost effectiveness and satisfaction for the end user. In optical fiber networks, on the other hand, search efforts instead concentrated on simple low-cost, future-proofness against inheritance and high services and applications through optical transparency. The ultimate goal of providing access to information when needed, was considered significantly. Whatever form it is required, not only increases the requirement sees technology convergence of wireless and optical networks but also played an important role in future communication networks. Some technical development of wireless access networks-optical and seamless coexistence of both techniques, this paper is a review of the State of the latest developments and advances in optical and wireless communications, major technical challenges to provide flawless communication in fiber- wireless (FiWi) access networks, places of interest important research issues to provide intelligence information, access and transport and the convergence of these networks in the future.</p>

OFs (Optical Fibers) are broadly used for information broadcast systems due to their extensive information-carrying capability and dielectric environment. The OFs network architectures that use several WLs (wavelengths) per OFs connect thousands of users in central, urban, or large-scale applications with a wide range of transmission speeds and capabilities. This article defines a detailed introduction to optical fiber networks and general phases of communication of OF (Optical Fiber) procedure. The taxonomy may be based on optical fibers such as; (i) Structure, (ii) number of modes, (iii) refractive index profile, (iv) dispersion, (v) signal processing capacity (vi) Polarization. After that, it explains the merits and demerits of optical fiber networks. They studied optical wireless communications applications such as SMs (shopping malls), UW (underwater), industries, etc. Several analyses with different optimization methods such as Genetic Algorithm (GA), Ant Colony Optimization (ACO), and Particle-Swarm Optimization (PSO) algorithms. An effective resource-allocation method is required to reduce the issue of EE (energy-efficiency) and improve the presentation of quality-of-services of the ONs (Optical Networks).

Traditionally, wireless and optical fiber networks have been designed separately from each other. Wireless networks aimed at meeting specific service requirements while coping with particular transmission impairments and optimizing the utilization of the system resources to ensure cost-effectiveness and satisfaction for the end user. In optical networks, on the other hand, research efforts rather focused on cost reduction, simplicity, and future-proofness against legacy and emerging services and applications by means of optical transparency. With the ultimate goal of providing access to information when needed, wherever needed, and in whatever format it is needed, the vision of technological convergence of wireless and optical networks is not only becoming a necessity but also plays a key role in future communications networks. Towards the technical evolution of wireless-optical access networks and the seamless coexistence of both technologies, this paper provides a review of state-of-the-art developments and advances in wireless and optical communications, presents key technical challenges for providing seamless communications in fiber-wireless (FiWi) access networks, and highlights important research issues for providing intelligence, transport, access, and convergence of these future networks.

Extending the researches on wavelength switched optical networks (WSON), efficient integration of the novel optical packet switching network and wavelength switching-based optical circuit switching network technologies which offers both best-effort packet delivery and QoS guaranteed lightpath services has been being studied. In addition, researches on the optical-layer transparent data processing, such as all-optical wavelength multicasting, all-optical 3R regeneration, etc, are conducted simultaneously. It is believed that future innovative optical network services (INSes) would be built on these novel future-proof technologies, and foster colorful applications in the new generation networks. Before the wide applications of INS in different fields, there would be a foreseeable strong requirement for INS firstly posed by pioneer grid applications, e.g., e-science, e-government, and e-banking, etc, which would require the high-performance underlying networks. Our research here is motivated to glue the optical networks and grid applications by integrating lightpath, geographically distributed INS systems and grid resources (e.g., computers, storages, instruments, etc.), and finally offering an easy-to-use high performance networked grid computing environment-optical grid network (OGN) to user applications. In this paper, we introduce our research activities of a distributed optical grid network infrastructure (OGNI), and the creation of the future easy-to-use INS based on OGNI. The proposals have been validated through fieldtrial experiments over a developed WSON testbed.

5G communications will require the effective transmission of new radio signals through fiber networks, in order to facilitate the proliferation of antenna sites as well as greater pooling of resources. Next generation optical access networks can provide an efficient platform for mobile x-haul. Techniques discussed in this paper shows how both wired and 5G wireless services may be converged over a single fiber infrastructure, and how optical networking can be harnessed in order to provide flexible millimeter-wave radio-over-fiber.

The evolution of telecommunications has allowed the development of broadband services based mainly on fiber optic backbone networks. The operation and maintenance of these optical networks is made possible by using supervision platforms that generate alarms that can be archived in the form of log files. But analyzing the alarms in the log files is a laborious and difficult task for the engineers who need a degree of expertise. Identifying failures and their root cause can be time consuming and impact the quality of service, network availability and service level agreements signed between the operator and its customers. Therefore, it is more than important to study the different possibilities of alarms classification and to use machine learning algorithms for alarms correlation in order to quickly determine the root causes of problems faster. We conducted a research case study on one of the operators in Cameroon who held an optical backbone based on SDH and WDM technologies with data collected from 2016-03-28 to “2022-09-01” with 7201 rows and 18. In this paper, we will classify alarms according to different criteria and use 02 unsupervised learning algorithms namely the K-Means algorithm and the DBSCAN to establish correlations between alarms in order to identify root causes of problems and reduce the time to troubleshoot. To achieve this objective, log files were exploited in order to obtain the root causes of the alarms, and then K-Means algorithm and the DBSCAN were used firstly to evaluate their performance and their capability to identify the root cause of alarms in optical network.

Starnet, a fiber optic metropolitan area network with centralized control

Chapter 9 - Testing Fiber Optic Local Area Networks (LANs)

In recent times, fiber optic communication networks have become commonly applied for commercial as well as military applications. Fiber optic networks have gained popularity owing to the high data rate. At the same time, the generation of huge quantity of data at a faster rate poses a major challenge in the storing and transmission process. To resolve this issue, data compression approaches have been presented to reduce the quantity of transmitted data and thereby minimizes bandwidth utilization and memory. Vector quantization (VQ) is a commonly employed image compression technique and Linde Buzo Gray (LBG) is used to construct an optimum codebook to compress images. With this motivation, this paper presents a new oppositional glowworm swarm optimization based LBG (OGSO-LBG) technique for image compression in fiber optic communication. The OGSO algorithm involves the integration of oppositional based learning (OBL) concept into the GSO algorithm to boost its convergence rate. The OGSO-LBG algorithm produces the codebook at a faster rate with minimal computation complexity. In order to highlight the enhanced compression performance of the OGSO-LBG technique, a series of experiments were carried out and the results are examined under different dimensions.

With this paper we bring about a discussion on the computing potential of complex optical networks and provide experimental demonstration that an optical fiber network can be used as an analog processor to calculate matrix inversion. A 3x3 matrix is inverted as a proof-of-concept demonstration using a fiber network containing three nodes and operating at telecomm wavelength. For an NxN matrix, the overall solving time (including setting time of the matrix elements and calculation time of inversion) scales as O(N(2)), whereas matrix inversion by most advanced computer algorithms requires ~O(N(2.37)) computational time. For well-conditioned matrices, the error of the inversion performed optically is found to be around 3%, limited by the accuracy of measurement equipment.

We address the QoS (Quality of Services) bandwidth reservation and service work scheduling mechanism of how to fairly provide advance quality of service in polling based TDM networks like Ethernet PON (Passive Optical Networks). Unlike existing differentiated QoS supporting schemes, such as SP (Strict Priority) based DBA (Dynamic Bandwidth Allocation) or static work scheduling with min-max theory, proposed service quality pre-engagement (SQP) for prioritized packet scheduling and equal weighted fair bandwidth arbitration (EWF-BA) for fair services among access nodes reflect the dynamically changing service pattern of access node like ONU (Optical Network Unit). The performance results show that the service fairness and QoS are tightly coupled and proposed mechanisms achieve better QoS performances with high fairness and better network performances both in Poisson and Self-similar traffic environment.KeywordsQueue SizeOptical Network UnitAccess NodePassive Optical NetworkDynamic Bandwidth AllocationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Development of modern optical fiber networks puts an increasing demand on the optical hardware. All-optical signal processing components enable the highest switching rates and allow all-optical regeneration of pulse streams without converting the optical signal into electrical current. The subject of our research is self-switching in a Mach-Zehnder interferometer (MZI) and its applications in optical telecommunication networks. In this device, light injected in one of the input ports is unequally distributed over the two interferometer arms. Due to the intensity dependent refractive index in the interferometer arms, there can be a nonlinear phase shift induced between the optical signals of unequal intensities. The two signals therefore interfere destructively or constructively depending on the input power: in this way we obtain nonlinear self-switching. Two mechanisms of nonlinear phase shifting were considered: active, based on semiconductor optical amplifiers (SOAs), and passive, based on quantum dots (QDs). Interferometers of two types were developed: 2-to-2 (two input ports and two output ports) and 2-to-1 (two input ports and one output port). The 2-to-2 SOA-MZIs based on self-switching have been investigated for two applications. One of them is the pattern effect compensator. If SOAs are employed for all-optical signal amplification, e.g. in optical access networks, an unwanted pulse distortion (known also as the pattern effect) takes place, as a result of the SOA gain saturation. Our component allows pattern-free amplification of the optical signals at bitrates up to 20 Gb/s. At 10 Gb/s it shows an extended input power range (up to 7 dB improvement) and comparable gain, which makes it suitable to be used as an optical amplifier. Another application of the 2-to-2 SOA-MZI is a 2R-regenerator. Optical amplifiers used in long distance optical links add noise to the optical signal, causing signal degradation. The signal can be regenerated by passing it through an optical gate with a nonlinear transfer function. The 2-to-2 SOA-MZI has such a nonlinear transfer function. The regeneration capabilities were demonstrated at 2.5 Gb/s by an improvement of the receiver sensitivity of about 2.5 dB. The dynamic characterization of the chips was carried out in a close cooperation with the research group COM at the Technical University of Denmark within the ePIXnet "network of excellence". The 2-to-1 MZI based on self-switching can be used as a low-loss optical combiner. An essential function in optical fiber networks is the combining of optical signals. A serious disadvantage of the conventional type of combiners used in the networks is that they let only half of the power (3 dB) through. In order to compensate for this loss, passive optical combiners are often used in combination with an in-line SOA. The first realization of the low-loss optical combiner uses SOAs as active phase shifters. Such an active low-loss combiner shows an improvement of transmission of over 2 dB compared to a conventional combiner with an in-line SOA. It is therefore expected that the output optical signal-to-noise ratio of the self-switching SOA-MZI is more than 2 dB better than that of a conventional combiner with an in-line SOA. While for the pattern effect compensator and the 2R-regenerator SOAs are used not only for inducing the nonlinear phase shift, but also for sufficient amplification, for the low-loss optical combiner the preferred nonlinear effects should be passive: combination of the signal is a passive function. Therefore, the second realization is based on a novel material, quantum dots. QDs provide improved all-optical nonlinearities resulting in a very small switching energy and large refractive index changes. Such a passive 2-to-1 QD-MZI based on self-switching showed an improvement up to 1.7 dB with respect to a conventional combiner. These improvements have a huge effect on e.g. the power budget in passive optical networks, where a large number of splitting stages are required. The Mach-Zehnder interferometers were realized in the InP/InGaAsP semiconductor material system, which is perfectly suitable for the integration of the photonic integrated circuits for the telecommunication applications. In order to realize both active components (such as e.g. SOAs) and passive components (such as e.g. waveguides, couplers), an active-passive integration technique was applied. This integration was realized in a close cooperation between JDS Uniphase Eindhoven and the COBRA Research Institute. It employs a three-step metal-organic vapor-phase epitaxy regrowth process. The quantum dot material was grown within the COBRA Research Institute. Our MZIs use a ridge waveguide design, for which a reactive ion etching process was developed in the COBRA cleanroom. As a result of photonic integration our integrated Mach-Zehnder interferometers have very small dimensions: less than a square millimeter.