Growing Demand For Bandwidth Research Articles

A survey of millimeter wave backscatter communication systems

Backscatter communication is an emerging low-power communication technology that has been integrated into the Internet of Things (IoT) due to its exceptional self-sustainability. However, conventional backscatter communication (BackCom) technologies often encounter limitations in data transmission rates, making it challenging to meet the growing bandwidth demands of IoT applications. In contrast, millimeter wave (mmWave) BackCom exhibits significant potential for high-speed data transmission owing to its abundant spectrum resources. Therefore, this paper presents a comprehensive survey of the existing literature on mmWave BackCom. We start by introducing the fundamental principles of mmWave BackCom, encompassing its architecture, basic techniques, and foundational knowledge. Subsequently, we review various mmWave backscatter communication techniques proposed in the current literature. Finally, we discuss several applications based on these techniques before finally addressing challenges and open issues associated with mmWave backscatter.

Advanced Considerations Concerning Impact of Applied Call Admission Control Mechanisms on Traffic Characteristics in Elastic Optical Network Nodes

Over the past few years, a significant increase in network traffic volumes has been observed. The ever growing bandwidth demands mean that a reliable and optimum service level needs to be ensured in communication systems for specific traffic categories. Optimal allocation and use of resources may be achieved through the use of call admission control (CAC) mechanisms implemented in network systems. The resource reservation mechanism and the threshold mechanism are two of the most popular CAC methods. In the reservation mechanisms, a certain number of resources is reserved for selected (predefined) services only. In the case of threshold mechanisms, the number of resources allocated to individual traffic classes depends on the network load. This article discusses the results of simulations verifying the impact of applied CAC mechanisms on the traffic characteristics in elastic optical network (EON) nodes with a Clos structure. Loss probability results obtained with the use of the simulator are presented as well.

Key Technologies for a Beyond-100G Next-Generation Passive Optical Network

The explosive development of emerging telecommunication services has stimulated a huge growth in bandwidth demand as people seek universal access to telecommunication networks. In addition, the kinds of services of an existing optical access network are becoming more flexible. In order to provide higher capacity and meet higher transmission performance requirements, it is necessary to further explore the application of the beyond-100G passive optical network (PON). This paper offers a comprehensive review and outline of the prospects of technologies for bringing a beyond-100G PON to practical applications in the future. We review the current existing technologies, mainly in terms of the physical layer and higher media access control layer. These key technologies for the beyond-100G PON, which plays an increasingly significant role, include the advanced multiplexing technology, physical layer digital signal processing technology, infrastructure-sharing technology, security protection technology, and intelligent control management key technologies. Finally, open issues and new challenges for the next-generation PON are focused upon.

Comparative analysis of techniques in long reach passive optical networks: overview and design

Abstract Long reach PON is an attractive option for addressing the growing bandwidth needs of internet applications and also serving multiple ONUs. Due to newly augmented technologies such as 4K/8K television, video meetings/conferencing, and online gaming, end-user bandwidth demands are exponentially rising day by day. Wavelength division multiplexing–based passive optical network (WDM-PON), which can deliver high data rates over long distances, is the ultimate solution to the growing bandwidth demand. It is possible to reduce the number of active cabinets and central offices while increasing the number of optical network units (ONUs) with the use of passive optical networks (PONs). At higher bit rates, researchers faced lot of issues like increased pulse width due to increased distance, burst loss, fault detection, etc. In this paper, we have discussed few challenges faced in passive optical networks. Also, we have discussed about the methodology to overcome these issues.

Silica micro-rod resonator-based Kerr frequency comb for high-speed short-reach optical interconnects.

Conventional data center interconnects rely on power-hungry arrays of discrete wavelength laser sources. However, growing bandwidth demand severely challenges ensuring the power and spectral efficiency toward which data center interconnects tend to strive. Kerr frequency combs based on silica microresonators can replace multiple laser arrays, easing the pressure on data center interconnect infrastructure. Therefore, we experimentally demonstrate a bit rate of up to 100 Gbps/λ employing 4-level pulse amplitude modulated signal transmission over a 2 km long short-reach optical interconnect that can be considered a record using any Kerr frequency comb light source, specifically based on a silica micro-rod. In addition, data transmission using the non-return to zero on-off keying modulation format is demonstrated to achieve 60 Gbps/λ. The silica micro-rod resonator-based Kerr frequency comb light source generates an optical frequency comb in the optical C-band with 90 GHz spacing between optical carriers. Data transmission is supported by frequency domain pre-equalization techniques to compensate amplitude-frequency distortions and limited bandwidths of electrical system components. Additionally, achievable results are enhanced with offline digital signal processing, implementing post-equalization using feed-forward and feedback taps.

Scalability of Large-Scale Photonic Integrated Circuits

To keep up with the growing bandwidth demands, photonic integrated circuits (PICs) have been widely employed in various application scenarios where high capacity and high-bandwidth-density interconnects are required. However, it is challenging to scale the PICs toward future petabit per second capacity requirements. We study the scalability bottlenecks of PICs in terms of guiding materials, dense integration approaches, wide-band optical sources, and high-efficiency tunable and modulation devices. We also look for possible solutions to address these challenges. In the end, we provide a perspective on future PIC development. Moore’s law for integrated photonics may last for a much shorter time than that in the microelectronics industry, requiring significant innovations and technological breakthroughs in PIC research.

Blockchain-enhanced cross-ISP spectrum assignment framework in SDONs: SpectrumChain

Huge potentials of optical networks provide an excellent choice in meeting the exponential growth in bandwidth demand. In particular, Elastic Optical Networks (EONs), with its promising potentials in increased availability, failure resilience, load-balancing, and efficient resource allocations, are good candidates for the future high-speed networks. When EONs are augmented with the emerging Software Defined Networking (SDN) architecture, which decouples the data and control planes, an agile and synergistic combination emerges under a general term of Software Defined Optical Networking (SDON), albeit with operational challenges such optimal and efficient spectrum assignments. In this paper, we present a blockchain-enhanced QoS-concentrated cross-Internet Service Provider (ISP) spectrum assignment framework for SDONs, SpectrumChain (SC), to eliminate centralized mediators while coordinating QoS-based inter-ISP traffic. This study introduces a new blockchain use-case with reduced QoS signaling overhead while performing inter-ISP routing in SDONs. We also experience the proposed framework under Hop-by-Hop Wavelength Switching (HWS), Border-Node-Only Wavelength Switching (BWS), and No Wavelength Switching (NWS) scenarios to analyze its performance. Our extensive simulation results show that the SC framework can effectively handle the QoS-enabled inter-ISP routing in SDON architecture in terms of Flow Setup Time (FST), Messages Processed (MEP), Requests Serviced (RS), and Acceptance Ratio (AR) metrics under HWS, BWS, and NWS scenarios.

Flexible and adaptive coherent PON for next-generation optical access network [Invited

With the official adoption of the single-wavelength 50G PON standard at the International Telecommunication Union Study Group 15 (ITU-T SG15) meeting, both industry and academia have started extensive research on the next-generation optical access network beyond 50G. It is envisioned that 100G and 200G per wavelength and even beyond will be required in the next-generation optical access network to support the continuously growing bandwidth demands. Coherent passive optical network (C-PON), which is based on multi-access coherent optics and digital signal processing (DSP), appears to be a promising candidate for future 100/200G and even beyond single-wavelength PON, thanks to its superior sensitivity compared with current direct-detection based PONs. Actually, multi-access coherent optics brings many benefits to the optical access network beyond the improvement of sensitivity. In this invited paper, we review recent studies and progress on the flexible C-PON for optical access network in terms of access speed, multiple-access architecture, and deployment scenarios. Rate-adaptive coherent access is first introduced in this paper as a promising solution to achieve flexible C-PON. Adaptive modulation formats based on constellation shaping is highlighted to realize fine granularity of information rate and wide flexibility. We have also discussed the flexible multiplexing schemes beyond TDM, to take the full advantages of coherent access. Finally, we analyze the flexible deployment scenarios under the large power budgets thanks to coherent detection. All these flexibilities provided by coherent access would be interesting and beneficial in the next generation optical access network.

Network resiliency and fiber usage of Tree, Star, ring and wheel based wavelength division multiplexed passive optical network Topologies: A comparative review

Wavelength division multiplexing (WDM)-based Passive Optical Networks (PON) has gained attention due to the massive growth in bandwidth demand resulting from the increased number of users, utilisation of bandwidth-hungry applications, network protection, reliability, survivability, scalability and mobility advents. Multiple architectures were proposed in the literature to achieve credibility and sustainability in WDM-PON networks. To identify the best approach, the current study presented a comparative analysis of recent and the most deployed WDN-PON topologies that mainly comprises tree, star, ring, and wheel. The study also discussed the advantages and disadvantages of every WDM-PON topology while outlining the research gap for future directions.

Design and Simulation of Physical Layer Security for Next Generation Intelligent Optical Networks

With the latest technological advancements and attractive features of next generation intelligent optical networks such as high bandwidth, low power consumption, and low transmission loss, etc., they have been considered as most viable solution to satisfy promptly growing bandwidth demands. However, main optical network components bring forth a set of security challenges and reliability issues, accompanied by new vulnerabilities within the network. This paper proposes a new design for an optical encryption and decryption method for enhancing optical network security using p–i–n photodiode which generates Pseudo Random Binary Sequence (PRBS) as a shot noise fluctuations and wavelength converter based design using Semiconductor Optical Amplifier based XOR gate which utilizes Cross-Phase Modulation. The system performance based on Bit Error Rate and Q factor are analyzed at different data rates for different link lengths up to 100 km using OptiSystem. It is observed that error free transmission with a BER of 10–12 is achieved a data rate of 10 Gbps for a link length of only 30 km for the system with PIN photodiode’s shot noise being used for PRBS sequence generation. However, wavelength conversion based system enables transmission of signal at 10Gbps signal up to a link length of 90 km.

Design of L + U‐band Erbium‐doped fiber amplifier based on a single S‐band forward pump source

SummaryThe multi‐band transmission (MBT) technique is one of the most cutting‐edge approaches to increase the capacity of fiber‐optic transmission systems and meeting the growing bandwidth demand. MBT technique considers the transmission in C + L‐ and U‐bands based on Erbium‐doped fiber amplifiers (EDFAs). Therefore, we propose a high gain and low noise figure EDFA for L + U‐band amplification having gain bandwidth of more than 82 nm in the spectral range of 1578–1660 nm, based on a single standard S‐band forward pump source. The L + U‐band amplification is obtained by pumping the gain medium which is heavily doped with Er3+. The results based on numerical simulations show that an efficient amplification is obtained over L + U‐band with an average small signal gain of around 39 dB covering 1578–1660 nm wavelength range while incorporating a short 12 m length of Erbium‐doped fiber (EDF) at an optimized pump power of 300 mW. A maximum noise figure of 4.46 dB is observed at 1593 nm. In addition, power conversion efficiency (PCE) of different C‐band pump wavelengths has also been evaluated, and the findings show that the PCE of 1560 nm pump wavelength is 70% higher than standard 1480 nm pump wavelength at the expense of cost efficiency. Finally, the system level performance of the designed L + U‐band EDFA is investigated in a five channel wavelength division multiplexed (WDM) link.

Routing and spectrum assignment employing long short-term memory technique for elastic optical networks

With the prevalence of some high bandwidth-demanding applications, such as cloud computing, traditional wavelength-division-multiplexing passive optical networks have difficulties in satisfying such growing bandwidth demands due to its limited allocation-flexibility and utilization-efficiency. Therefore, elastic optical networks (EONs). In order to realize the flexibility in EONs, sophisticated routing and spectrum allocation (RSA) algorithms areone of the keyenabling technologies. However, most of the previous RSA algorithms were proposed with invariant routing and spectrum allocation strategies, which ignored considering the time-varying characteristics of EONs due to the variable network architecture and service provisioning. And such time-varying characteristics can deteriorate the spectrum fragmentation and the service blocking performances of EONs, which stimulates the application of various machine-learning technologies in EONs. In this paper, a long short-term memory based routing and spectrum assignment (LSTM-RSA) algorithm is proposed for EONs. By employing the long short-term memory technique to sense the complex status of EONs (e.g. spectral usage on the selected paths), the proposed LSTM-RSA algorithm gradually learns successful strategies through accumulating operation experience in the process of interaction and obtains higher returns through enhanced operation, which helps improve the spectrum fragmentation and the service blocking performances in EONs. Simulation results show that the spectrum fragmentation rate and the blocking rate of the proposed LSTM-RSA algorithm are reduced by about 6% and 8.9%, respectively, when compared to the traditional shortest-path-routing first-fitting RSA algorithm.

White Light Communication: A Design for High School Experiment

As wireless communication carrier frequencies continually increase to respond to growing bandwidth demands, from hundreds of MHz (3G/4G) to dozens of GHz (5G), it would only be logical to postulate that the next step in this technological revolution would be to move to hundreds of THz, also known as visible light. This completely alleviates the carrier frequency induced bandwidth limitations while serving as ambient lighting. In this paper, a visible light communication setup capable of moderate bitrate serial communication with interference from ambient lighting will be presented. Furthermore, this paper proposes the implementation of a similar setup as a form of hands-on experiential learning for high school and undergraduate engineering students.

Predicting Product Uptake Using Bass, Gompertz, and Logistic Diffusion Models: Application to a Broadband Product

In today’s competitive environment, broadband companies innovate to stay competitive, retain existing customers, and attract new customers. A recent innovative product in this industry is the deployment of the gigabit Internet service over fiber optic networks as a solution to the growing bandwidth demands from consumers. One determinant of the decision to deploy such product is the expectation of a positive return on investment (ROI) determined among others by the penetration or take rate of the product or service. Like any product, the adoption of the gigabit Internet is influenced by the reaction of customers to this innovation. Some customers are early adopters of the product while others might not be interested in higher bandwidth Internet connections or will simply adopt the product at a later time. The purpose of this paper was to identify a model that best predicts future trends in the uptake of the gigabit Internet product over fiber-to-the home (FTTH). To that effect, this study implemented three different models: Bass, Gompertz, and logistic diffusion models; analyzed their predictive abilities; and determined the best fit model in a FTTH brownfield scenario. The data used for the study were split into two sets: the first or training set was used to create the models and the second was used to validate their predicting abilities. The data analysis used the ordinary least squares (OLS) method to select the best fit model. The results suggested that while Gompertz best fitted the training data, Bass had a better forecasting power. In other words, the Bass diffusion model was best at forecasting future uptake of the gigabit Internet service, while Logistic optimistically forecasted above the take rate and Gompertz pessimistically forecasted below. These findings present various implications for researchers and practicians. For example, future research could replicate the study for different industries and products, while practicians could anticipate realistic financial results from the implementation of the findings.

Key Enabling Technologies for the Post-5G Era: Fully Adaptive, All-Spectra Coordinated Radio Access Network with Function Decoupling

With the rapidly growing bandwidth demand for wireless applications, new system technologies related to post-5G are emerging. In this article, an all-spectra fully adaptive and coordinated radio access network (RAN) is reported and discussed. By employing a fiber-wireless integration and networking architecture, all data-carrying channels could be aggregated in the same fiber access infrastructure. This enables a coordinated RAN with function decoupling, in which lower RF, 5G New Radio (NR), sub-THz, and even lightwave are employed; also, different types of services are delivered depending on their physical layer properties. Promising scenarios are discussed, such as integrated access of wireless NR-free space optical (FSO) backhauling and indoor systems via visible light communication (VLC) and efficient NR beamforming aided by VLC positioning system. The former use case can enhance the network throughput and reliability. This is because both FSO and NR can support high channel capacity due to their abundant bandwidth. Meanwhile, with the advancement of novel DSP techniques, the stability of the NR-FSO link under diverse weather turbulences or suffering from burst mode interference can be enhanced. The latter scenario provides an alternative solution for high-speed data link and a simplified beam management via the VLC-aided positioning system. VLC can concurrently provide ubiquitous indoor illumination, data transmission, and positioning. With the help of artificial intelligence algorithms, a VLC-based precision positioning system can provide a location accuracy of less than 1 cm, and it is able to meet the narrow beam size of the NR beamformer in a 3D model. Therefore, it is foreseeable that an all-spectra function decoupled RAN can serve as a unified network platform to support all wireless applications while optimizing system throughput, channel condition, network coverage, and software/ hardware complexity for post-5G mobile data networks.

Relative cost routing and spectrum allocation in elastic optical networks

Elastic optical networks (EONs) are being used to adapt to the recent rapid changes in traffic behavior and the exponential growth in bandwidth demand. Routing and spectrum allocation (RSA) is one of the most important determining factors of the design, performance, and operation of EONs. In this work, we propose an adaptive RSA algorithm based on the relative cost concept under which the transient effect when a call is admitted on a given route/spectrum set at a given network state is estimated. The algorithm computes the relative cost of forwarding an arriving call across all available route/spectrum sets to the destination. The algorithm selects the route/spectrum set with the least relative cost; if the minimum relative cost is more than the call’s value, the call is potentially rejected. In this study, the efficiency of using relative cost to solve the RSA problem is demonstrated via simulation.

An optical packet metro architecture for Fixed Mobile Convergence in the cloud era

The present paper addresses future network architectures considered for Fixed Mobile Convergence, where users can access resources transparently either through fixed access technologies or through the mobile RAN. Optical technologies rely on Wavelength Division Multiplexing (WDM) to meet continuously growing bandwidth demands. However, although in the core network optical circuit switching may efficiently support huge traffic aggregates, closer to the access, in future Metropolitan Area Networks (MAN), it is necessary to provide a finer granularity, and a dynamical bandwidth control, to very heterogeneous traffic demands. This is supported by Optical Packet Switching (OPS) relying on WDM slotted Add/Drop Multiplexing (WSADM). A flow-based transfer mode, compatible with SDN control is first specified, and applied to bi-directional MAN rings. This mode is shown to provide several methods for supporting both local and global repair in case of failure. Mathematical models are derived to assess optical packet insertion performance and are used to illustrate how WSADM rings can support MAN performance requirements. Lastly the impact of locating the IP edge, and Data Centres closer to the users than in legacy architectures, within the MAN is addressed.

Machine Learning for 100 Gb/s/<italic>λ</italic> Passive Optical Network

Responding to the growing bandwidth demand by emerging applications, such as fixed-mobile convergence for fifth generation (5G) and beyond 5G, 100 Gb/s/ λ access network becomes the next research focus of passive optical network (PON) roadmap. Intensity modulation and direct detection (IMDD) technology is still considered as a promising candidate for 100 Gb/s/ λ PON attributed to its low cost, low power consumption, and small footprint. In this paper, we achieve 100 Gb/s/ λ IMDD PON by using 20G-class optical and electrical devices due to its commercial availability. To mitigate the system linear and nonlinear distortions, neural network (NN) based equalizer is used and the performance is compared with feedforward equalizer (FFE) and Volterra nonlinear equalizer (VNE). We introduce the rules to train and test the data while using NN-based equalizer to guarantee a fair comparison with FFE and VNE. Random data have to be used for training, but for test, both random data and pseudorandom bit sequence are applicable. We found that the NN-based equalizer has the same performance with FFE and VNE in the case of linear distortion, but outperforms them in a strong nonlinearity case. In the experiment, to improve the loss budget, we increase the launch power to 18 dBm, achieving a 30-dB loss budget for 33 GBd/s PAM8 signal at the system frequency response of 16.2 GHz, attributed to the strong nonlinear equalization capability of NN.

Earthquake Tolerant Energy Aware Algorithms: A New Approach to the Design of WDM Backbone Networks

The increasing energy cost of networking facilities, in conjunction with environmental instability and climate change, have led to many research efforts targeting the reduction of the energy consumption in telecommunication networks. Wavelength division multiplexing (WDM) optical networks is the key solution for the continuously growing bandwidth demands of backbone networks. However, the rise of traffic has led to the augmentation of energy consumption in such networks. Moreover, backbone networks in countries with high seismicity suffer from unexpected link failures caused by earthquakes, which in turn, cause a huge amount of bandwidth loss and service disruptions. In this paper, a new power aware algorithm is introduced, which uses actual seismic information in order to maintain tolerant connectivity of the backbone network after a large scale earthquake occurs, while supporting energy efficiency. The objective of this paper is the design of a power and earthquake aware WDM backbone network, by establishing the minimum number of backup links in the virtual topology in order to maintain tolerant connectivity. The proposed scheme is evaluated via extensive simulation results by using actual seismic information provided by the Geodynamic Institute of the National Observatory of Athens, and it is verified that both goals of earthquake tolerance and energy efficiency are achieved.

100 Gb/s to 1 Tb/s Based Coherent Passive Optical Network Technology

Following on from current 1 Gb/s to 10 Gb/s based passive optical networks (PON), IEEE 802.3ca has commenced discussion of the first 100 Gb/s-based PON standard in the form of 100 G Ethernet PON (100G-EPON), in anticipation of growing bandwidth demand by emerging applications such as fixed-mobile convergence for 5G and beyond 5G (B5G) where mobile front-haul and mobile back-haul (MFH/MBF) will require greatly increased capacity of up to 1 Tb/s. In the move toward these 100 Gb/s to 1 Tb/s class PONs, research into the latest coherent technology based PON systems is being pursued due to its high receiver sensitivity at much higher bit rates, superior to current direct-detection based PON systems, aided by the rapid progress of the latest small-scale digital signal processing (DSP) suitable for access spans of less than a few tens of km. In this paper, we review the recent progress of such 100 Gb/s to 1 Tb/s class coherent PON technology. As the key successful factor for realizing 100 Gb/s to 1 Tb/s based coherent PON systems, the latest trends in coherent DSP and the accompanying embedded coherent transceivers are summarized from the point of view of miniaturization. In addition, highlighting the strong progress with the upcoming coherent PON systems, the first demonstration of a 100 Gb/s/λ × 8 wavelengths (800 Gb/s) based real-time wavelength division multiplexing (WDM)-PON system using a simplified DSP suitable for access spans is presented. A 100 Gb/s/λ based time division multiplexing (TDM)-PON system is also introduced, addressing the burst-mode coherent reception technique which will be the main issue for achieving practical TDM-based coherent PON systems.