Wireless-optical Broadband Access Network Research Articles

Positioning multiple optical network units in fiber-wireless networks: An efficient hybrid [formula omitted]-harmonic means clustering approach

Wireless-optical broadband access network (WOBAN) or fiber-wireless (FiWi) is a robust and cost-effective solution to provide high bandwidth network connectivity to mobile subscribers. Optical network unit (ONU) placement is a topological optimization problem that plays a vital role in effective deployment of FiWi network. Recently, some artificial intelligence-based approaches for positioning ONUs were proposed and generated promising results. However, the reported performance in the literature is far from the ideal state. This issue emphasizes the necessity of introducing new placement methods or improving the performance of existing methods. This paper presents a hybrid clustering algorithm for finding the optimal position of multiple ONUs. The proposed backtracking K-harmonic means (BKHM) is an integration of K-harmonic means (KHM) and a backtracking search algorithm (BSA). BKHM not only efficiently specifies the optimal positions of ONUs but also significantly decreases the implementation cost. To demonstrate the performance of the BKHM, we evaluate it on well-known placement benchmarks compared with BSA, KHM, whale optimization algorithm (WOA), enhanced backtracking search (EBS), harris hawks optimization (HHO), and chaotic local search-based levy flight distribution (CLF) algorithms. The experimental results and statistical analysis proved that the proposed BKHM algorithm outperformed its counterparts on most benchmarks in terms of cost optimization, convergence accuracy, and solution quality.

Front-End Survivability in Wireless Optical Broadband Access Network

Background: Survivability is the one of the key issue of wireless optical broadband (WOBAN) access network. Survivability means to provide continuous services to users if a device/link failure occurs in the network Objective: The component link failure can occur in the network due to any reason. In this condition huge data loss will occur in the network. Methods: In this paper, we consider the front-end survivability in WOBAN. We propose a novel maximum protection minimum link cost routing algorithm (MPMLC) that provides path protection with minimum link cost to front-end of the WOBAN. The proposed MPMLC algorithm assigns weight/cost to wireless link using link state prediction (LSP). Results: The path with minimum cost is selected to route the traffic (actual/affected due to failure) of front end network. The proposed algorithm outperforms in terms of reduced network delay and wireless link cost Conclusion: It is also observed from simulation results that when the multiple link failures occur in the network, proposed MPMLC algorithm exhibit better results in terms of reduced wireless link cost as compared to existing algorithm.

Fault‐tolerant wireless‐optical broadband access network with cluster‐controlled architecture

SummaryThe ever increasing demand in wireless connectivity has led PON networks suffer from limitations in mobility and wide area coverage. Wireless networks suffer by bandwidth limitations. Hybridization uses the best characteristics of all networks: wireless networks and optical networks. A lightweight wireless mesh network is a wireless‐optical broadband access network (WOBAN), which has a front end and background effective bandwidth optical network. WOBAN has already suffered from two large network feature faults as well as feeder and fiber breaks. Cluster‐based protection (CBP) mechanism is proposed in order to increase traffic recovery reliability and reduce backup fiber deployment. With minimal fiber distribution cost, CBP efficiently manages single and simultaneous failures from many segments. Long‐term evolution (LTE) technique‐based CBP is implemented in WOBAN. Faults are analyzed by injecting wireless/distribution fiber/multiple feeder fiber. The novel fault tolerant network is built using an efficient automated failure detection and rerouting (AFDRR) algorithm. An efficient automated failure detection and rerouting (AFDRR) algorithm is used for developing the novel fault‐tolerant network. Implementation of orthogonal frequency division multiplexing (OFDM) technology‐based AFDRR‐CBP on WOBAN‐LTE network with the same scenario is analyzed through simulation. The performance measures are compared among CBP‐WOBAN‐LTE network, AFDRR‐CBP‐WOBAN‐LTE network, and OFDM‐based AFDRR‐CBP‐WOBAN‐LTE networks. From the result obtained, it will be revealed that the suggested methodology throughput ratio will increase up to 24.4% when compared to other methodology.

Deployment of Cost-Efficient Cloud Integrated WOBAN: A Cluster- Based Approach

Aim: To deploy Cloud Components in a cloud integrated WOBAN in a cost-efficient manner. Background: Wireless-Optical Broadband Access Network (WOBAN) is a network which provides higher bandwidth and better stability at lower cost to the users. Integration of cloud services over traditional WOBAN called as CIW (cloud integrated WOBAN) increases existing load carrying capacity and available bandwidth. In CIW, Cloud Components (CCs) are integrated as storage components, servers etc. within WMN of WOBAN. These cloud components may follow distributed or centralized architectures. Availability of these low-cost and easy-to-deploy CCs make CIW technologically feasible and practically deployable architecture. Objective: The proposed algorithm eliminates redundant ONUs and optimizes number of CCs while ensuring network connectivity and cloud services to all users. Methods: Extensive simulation is carried out to implement proposed work. A simulation model and code is developed in MATLAB to get the results for existing and proposed algorithms for varying number of variables such as number of ONUs, wireless routers, grid sizes etc. Result: We compare the performance of proposed algorithm with existing algorithm for varying grid sizes as well as number of wireless routers. Simulation results show the worthiness of proposed work. Conclusion: Optimization of cloud components in CIW is one of the important issues as it affects overall network deployment cost. Considering this issue, we proposed a cluster based approach to optimize number of network components such as CCs and ONUs in the network. Simulation results show that cluster based approach is efficient as compared to existing approach for optimizing CCs. Hence proposed solution offers a suitable candidature for deploying a cost efficient CIW.

Cloud-integrated Wireless-optical Broadband Access Network with Survivability

Background: Cloud-Integrated Wireless Optical Broadband (CIW) access networks inheriting advantages of cloud computing, wireless and optical access networks have a broad prospect in the future. Objectives: Due to failure of components like OLT level, ONU level, link or path failure and cloud component level in CIW, survivability is becoming one of the important issues. Methods: In this paper, we have presented cloud-integrated wireless-optical broadband access network with survivability using Integer Linear Programming (ILP) model, to minimize the number of cloud components while providing maximum backup paths. Hence, we have proposed protection through cloud-integrated wireless router to available ONUs (PCIWRAO). Results: So, evaluated the backup path computation. We have considered ONU level failure in which the affected traffic is transferred through wireless routers and cloud component to the available ONUs using Manhattan distance algorithm. Conclusion: Simulation results show different configurations for different number of routers and cloud components illustrating available backup path when ONU fails.

A Review on MIMO Wireless Signals over Fibre for Next Generation Fibre Wireless (FiWi) Broadband Networks

Next-generation access/mobile networks have set high standards in terms of providing wireless services at high data rates in order to keep up with the vast demands for other mobility and multiple services. Wireless-optical broadband access network (WOBAN) technology, also known as fibre-wireless (FiWi), has uncovered incredible opportunities for the future of next-generation networks because it gets the best of both domains: huge bandwidth provided by the optical fibre and high ubiquity of the wireless domain. The objective of FiWi networks is to integrate the high data rate and long reach provided by optical networks and the ubiquity and mobility of wireless networks, with the target to decrease their expense and complexity. Multiple-input–multiple-output (MIMO) is an inevitable technique for most of the new mobile/wireless networks that are driven by the huge data rates required by today’s users. Consequently, to construct any FiWi system for next-generation (NG) access/broadband networks, an MIMO technique has to be considered. This article presents a comprehensive, contemporary review of the latest subsystems, architectures and integrated technologies of MIMO wireless signals backhauling using optical fibre or fibre access networks, such as passive optical networks (PONs). An overview for FiWi, PONs and MIMO wireless systems is provided. In addition, advanced techniques of accommodating the MIMO wireless signals over optical fibre are explained and compared. Different types of wireless MIMO signals over fibre, such as 5G, WiFi and related transport technologies, are reviewed. Moreover, future research trends are also discussed.

Critical Routers Identification to Handle Distribution Fiber Failure in Wireless Optical Broadband Access Network (WOBAN)

Abstract In this era of capricious Infobesity, every technology demands advancement in the form of increased bandwidth and lower latency, which can be provided by wireless optical broadband access network. Wireless Optical Broadband Access Network (WOBAN), conflating the benefits of both optical networks by providing higher data bandwidth, low latency, long communication lines, low loss, high reliability, high performance-to-cost ratio, etc. and wireless networks by providing greater accessibility, flexibility, easy networking. Due to various advantages of WOBAN as compared to the contemporary broadband networks, WOBAN has been a recent attraction for various researchers. Survivability is one of the critical issue in WOBAN due to its high speed characteristics. To handle this failure particularly distribution fiber failure, we present this work to identify critical wireless routers and their optimum positions. Here critical wireless routers are necessary to transfer disrupted traffic from affected ONU to its backup ONU in case of failure.

An optimization framework for FiWi access network: Comprehensive solution for green and survivable deployment

Abstract Fiber Wireless (FiWi) access network also known as hybrid wireless optical broadband access network is a promising modern access technology as it provides high bandwidth, better flexibility, reliability and stability at lower cost. Likewise other access networks, energy saving and survivability are the most important issues in FiWi also. Therefore this paper provides an optimization framework as a comprehensive solution for deployment of green and survivable FiWi network. We optimize ONUs position in the network using different optimization algorithms such as genetic algorithm, teaching learning based optimization algorithm and whale optimization algorithm (Encircling Prey and Spiral Update Positioning). This optimization helps in achieving energy efficiency and survivability by mutually connecting maximum possible ONUs and wireless routers to each other. An extensive simulation is carried out to show the effectiveness of the present work. Simulation results show reduction in number of all time active ONUs, total physical distance among ONUs and associated wireless routers and total active time of the network. At the same time survivability is achieved by increasing average ONU connectivity of wireless routers. A detailed comparison of applied algorithms states that out of different optimization algorithms, genetic algorithm provides best energy efficiency but average survivability. Teaching learning based optimization & whale optimization algorithm (Encircling Prey) are average energy efficient but survivability offered by these algorithms are average and excellent respectively. Similarly whale optimization algorithm (Spiral Update Positioning) provides good energy efficiency but average survivability. Hence as per the need of energy efficiency and survivability, suitable optimization algorithm can be selected for deployment of green and survivable FiWi access network.

Wavelength-agile and radio-agile FiWi access network using dynamic scheduling to improve upstream delay and resource utilization

Fiber wireless (FiWi) access network which is also referred as hybrid wireless optical broadband access network is one of the modern architecture to solve the problem of bandwidth availability and flexibility simultaneously. It integrates wireless frontend with optical backend. In FiWi network most of component remains idle for large duration, hence efficiency is very crucial. To improve energy efficiency in FiWi many multiple access (MA) techniques had been implemented at backend. However inclusion of multiple access techniques usually incur problem of delay, as data transfer in such network takes place only in the assigned slot of access technique. In this paper a novel architecture is proposed for FiWi which implements wavelength agile hybrid multiple access at backend and radio agile access technique at frontend. Further to improve delay performance, bandwidth availability and utilization of resources; a new scheduling approach is proposed for multiple access techniques implemented at frontend as well as backend. Delay performance, wavelength availability and load handling capacity of proposed approach is compared with different hybrid multiple access architecture. To best of our knowledge, wavelength agile and radio agile MA has been used for the first time in FiWi, moreover the proposed scheduling approach implemented on MA provide promising results in terms of delay and resource utilization. The performance of proposed work is also evaluated in terms of service and reservation delay component to indicate its utility in terms of actual information content per frame. The result shows effectiveness of proposed architecture over other existing architectures.

Green and Sustainable Cloud of Things: Enabling Collaborative Edge Computing

The proliferation of IoTs beside the emergence of various cloud services push the horizon of edge computing. By offering cloud capabilities at the network edge closer to mobile devices, edge computing is a promising paradigm to resolve several vital challenges in IoTs, such as bandwidth saturation, energy constraints, low latency transmission, and data security and privacy. To provide a comprehensive understanding of edge computing supported by the integration of IoTs and cloud computing, that is, CoTs, this article first discusses some distinct research directions in CoTs with respect to edge computing. Given the significance of energy efficiency and sustainability of edge deployment in CoTs, we put forward a green and sustainable virtual network embedding framework for cooperative edge computing in wireless-optical broadband access networks. Specifically, we leverage a reliability function to confirm the number of backup edge devices, and embed virtual networks onto the suitable edge devices in CoTs. Finally, several research challenges and open issues are discussed.

A Joint Routing and Channel Assignment Scheme for Hybrid Wireless-Optical Broadband-Access Networks

In this paper, we investigate mechanisms for improving the quality of communications in wireless-optical broadband access networks (WOBAN), which present a promising solution to meet the growing needs for capacity of access networks. This is achieved by using multiple gateways and multi-channel operation along with a routing protocol that effectively reduces the effect of radio interference. We present a joint route and channel assignment scheme with the objective of maximizing the end-to-end probability of success and minimizing the end-to-end delay for all active upstream traffic in the WOBAN. Performance evaluations of the proposed scheme are presented using ns-2 simulations, which show that the proposed scheme improves the network throughput up to three times and reduces the traffic delay by six times in presence of 12 channels and four network interface cards (NICs), compared to a single channel scenario.

Green Survivable Collaborative Edge Computing in Smart Cities

As an integrated environment deployed with wired and wireless infrastructures, the smart city heavily relies on the wireless-optical broadband access network. The information flows captured by indoor devices are sent to optical network units through front-end wireless mesh sensor networks (WMNs) and, finally, reach the optical line terminal for industrial/commercial decision making via the passive optical network backhaul. To reduce the backhaul bandwidth saturated by this conventional approach, edge devices are deployed at the front-end WMN to preprocess information flows. Based on collaborative edge computing, home users or factory workers customize their computing services as virtual networks embedded onto the common WMN. In this paper, we propose the green survivable virtual network embedding for the collaborative edge computing in smart cities. We mathematically formulate the problem and derive the corresponding bound. Extensive simulations with real traces demonstrate the algorithm effectiveness.

A New Lossless Fault-Tolerance Mechanism in Hybrid Wireless-Optical Broadband Access Network

With the tremendous growth of the traffic demand of emerging 5G applications, the survivability has become more significant in the wireless-optical broadband access network (WOBAN), since any failure of the network components could interrupt a large amount of traffic. A large amount of data could be lost even if there is a very short interruption. Previous works focus on finding the alternate paths or deploying backup fiber to recover the interrupted traffic. However, these works encounter three potential problems. First, the deployment of a backup fiber could increase the cost of recovery. Second, they must reroute the interrupted traffic to the backup resources, which could cause a long recovery time. Third, a large number of network packets could be lost during the recovery processes. To address these problems, a lossless fault-tolerance mechanism combining with parallel routing and network coding (LFTM-PR-NC) is proposed in this paper to enhance the survivability of WOBAN against any optical network unit-level and wireless-level failures. Numerical results show that the proposed LFTM-PR-NC mechanism significantly outperforms the previous mechanism. Meanwhile, the LFTM-PR-NC mechanism could dramatically decrease the recovery time when a failure occurs.

Video Service Recovery Mechanism Based on Quality of Experience-Aware in Hybrid Wireless-Optical Broadband-Access Network

A video service recovery mechanism based on quality of experience (QoE) aware is proposed to unambiguously evaluate the quality of video service and recover the unacceptable video service in hybrid wireless-optical broadband-access network (WOBAN). The QoS parameters are modeled to the objective metric of QoE. Furthermore, the objective metric of QoE is mapped to the subjective MOS value. And the unacceptable video service is recovered by searching for a recovery routing which has better QoE. The recovery rerouting problem is divided to the subproblem of selecting the object mesh portal point and the subproblem of searching the alternate routing. The object mesh portal point is selected by the basis of load balance. And the subproblem of searching alternate routing is addressed by the Dijkstra mechanism to find the path which can provide the best QoE for the video service. Simulation results show that the proposed mechanism can effectively improve the quality of video services.

Optical network unit placement in Fiber-Wireless (FiWi) access network by Moth-Flame optimization algorithm

Abstract Hybrid wireless-optical broadband access network (WOBAN) or Fiber-Wireless (FiWi) is the integration of wireless access network and optical network. This hybrid multi-domain network adopts the advantages of wireless and optical domains and serves the demand of technology savvy users. FiWi exhibits the properties of cost effectiveness, robustness, flexibility, high capacity, reliability and is self organized. Optical Network Unit (ONU) placement problem in FiWi contributes in simplifying the network design and enhances the performance in terms of cost efficiency and increased throughput. Several individual-based algorithms, such as Simulated Annealing (SA), Tabu Search, etc. have been suggested for ONU placement, but these algorithms suffer from premature convergence (trapping in a local optima). The present research work undertakes the deployment of FiWi and proposes a novel nature-inspired heuristic paradigm called Moth-Flame optimization (MFO) algorithm for multiple optical network units’ placement. MFO is a population based algorithm. Population-based algorithms are better in handling local optima avoidance. The simulation results are compared with the existing Greedy and Simulated Annealing algorithms to optimize the position of ONUs. To the best of our knowledge, MFO algorithm has been used for the first time in this domain, moreover it has been able to provide very promising and competitive results. The performance of MFO algorithm has been analyzed by varying the ‘b’ parameter. MFO algorithm results in faster convergence than the existing strategies of Greedy and SA and returns a lower value of overall cost function. The results exhibit the dependence of the objective function on the distribution of wireless users also.

Delay-aware adaptive sleep mechanism for green wireless-optical broadband access networks

Abstract Wireless-Optical Broadband Access Network (WOBAN) is capacity-high, reliable, flexible, and ubiquitous, as it takes full advantage of the merits from both optical communication and wireless communication technologies. Similar to other access networks, the high energy consumption poses a great challenge for building up WOBANs. To shot this problem, we can make some load-light Optical Network Units (ONUs) sleep to reduce the energy consumption. Such operation, however, causes the increased packet delay. Jointly considering the energy consumption and transmission delay, we propose a delay-aware adaptive sleep mechanism. Specifically, we develop a new analytical method to evaluate the transmission delay and queuing delay over the optical part, instead of adopting M/M/1 queuing model. Meanwhile, we also analyze the access delay and queuing delay of the wireless part. Based on such developed delay models, we mathematically derive ONU’s optimal sleep time. In addition, we provide numerous simulation results to show the effectiveness of the proposed mechanism.

Virtual Network Embedding for Collaborative Edge Computing in Optical-Wireless Networks

As an open integrated environment deployed with wired and wireless infrastructures, the smart city heavily relies on the wireless-optical broadband access network. Smart home data are usually sent to neighbor optical network units (ONUs) through front-end wireless mesh networks (WMNs) and finally reach the optical line terminal (OLT) for decision making via the passive optical network (PON) backhaul. To reduce backhaul bandwidth saturated by this conventional approach, smart edge devices (EDs) should be deployed at sensors and ONUs so that collaborative edge computing can be performed in front-end WMNs. Moreover, the cooperation of EDs at different ONUs is also promising for computing tasks that cannot be handled within front-end WMNs due to the local bottleneck, leading to collaborative edge computing in the PON backhaul. In this paper, network virtualization is utilized to support the coordination of computing and network resources. We also describe the relationship between virtual networks and requirements of computing tasks for substrate resources. First, a graph-cutting algorithm is employed to embed as many virtual networks as possible onto the common network infrastructure in front-end WMNs, aiming at minimizing the total transmitting power. Next, we transform impossibly embedded virtual networks into new ones that must be processed through the PON backhaul where the wavelength consumption will be optimized. Simulations results demonstrate that 1) the total transmitting power assigned for nodes is effectively reduced using the graph-cutting algorithm if all computing tasks can be solved by front-end WMNs; 2) otherwise, our method accepts more virtual networks with the improvement ratio of 77%, through the PON backhaul. In addition, there is a good match between the algorithm result and the optimal number of consumed wavelengths per optical fiber cable.

Performance Analysis of Survivable Hybrid Wireless Optical Broadband Access Networks

The ever increasing needs in internet connectivity leads to the demands for reliable high capacity networks. The future access networks will aimed to satisfy the end user needs through its large bandwidth, higher mobility, best QoS and wide area coverage. Wireless Optical Broadband Access Network (WOBAN) is a compromised solution which has flexible Wireless mesh network as its front end and robust bandwidth efficient Optical network as its back end. If a network element is failed in front end then the traffic will be rerouted in another path and provides reliable unthreaded connectivity. In case of single segment failure all optical network units (ONU)will be disconnected from the Optical line terminal (OLT) results huge data losses. In existing system optimizing backup ONU deployment scheme (OBOF) supports the survivability of WOBAN. The operational efficiency of WOBAN is improved by Automated Failure Deduction and Rerouting Algorithm (AFDRR) during single segment failure based on least congested routes. Implementations of AFDRR is performed in various wireless technologies like WiFi(802.11), WiMAX(802.16) and UMTS. Data packets are send from sender node to the receiver node and QoS parameters like throughput, end to end delay, packet delivery ratio,energy and path switching time are measured.

Load-Adaptive Resource Management for Green Wireless-Optical Broadband Access Network (WOBAN)

Wireless-optical broadband access network (WOBAN) is regarded as a promising broadband access network technology for meeting the challenges of the exponential increase in Internet traffic. WOBAN combines the reliability and capacity of the passive optical network (PON) with the ubiquity and mobility of the wireless network to cost efficiently deliver services to the end user. In common with other next generation communication networks, WOBAN faces the challenge of delivering very high data rates without sacrificing the quality of service (QoS) and energy efficiency. In this paper, we propose a new resource management technique for improving the energy efficiency of the integrated optical-wireless unit in WOBAN. The concept is based on increasing the idle time of the wireless and optical parts without sacrificing the QoS of end applications, and exploiting idle durations to enable sleep, which ultimately boosts power savings. We use the interoperability for resource management in the wireless and optical parts to maintain the QoS. Our results reveal that extending the idle time and making the resource management in both optical and wireless adapt to the daily traffic fluctuations guarantee the QoS requirements for different traffic and boost energy savings in WOBAN.

Green Wireless-Optical Broadband Access Network: Energy and Quality-of-Service Considerations

Growing energy demands in the information and communication technology (ICT) sector have been recognized as a major challenge worldwide. Researchers have been actively working to address this challenge, and the major focus centers around improving the energy efficiency of access networks, which are known for consuming about three-quarters of the total network power. Among various access networks, the hybrid wireless–optical broadband access network (WOBAN), which combines a passive optical network (PON) with broadband wireless technology, is highly regarded for its enormous capacity, cost efficiency, and ease of deployment. To develop a green WOBAN, it is important to focus on reducing its power consumption, and in this work, we present an efficient resource management technique for WOBAN that reduces the power consumption of the optical line terminal (OLT) and optical network unit (ONU) by introducing sleep modes for the OLT and ONU, based on the service class and traffic load. Moreover, it considers the quality-of-service requirement of each service class. Simulation results confirm that our proposed solution can save a significant amount of power in the WOBAN network without sacrificing the quality of service of end applications.