Chathurika Ranaweera

Next generation optical-wireless converged network architectures

This article provides a comprehensive analysis on implementing the next-generation optical-wireless integration architectures. The different approaches to implementing a complete fixed-mobile converged network that ensures desired quality of service for various applications are explored. This discussion is specifically focused on LTE-10GEPON integration networks where passive optical networks are used as the backhaul to LTE. Special attention is given to address the issue of providing proper means to enable intercommunication between neighboring base stations, which is one of the crucial considerations in next-generation wireless networks. We propose potential 10GEPON-LTE converged network architectures and comparatively analyze the benefits gained from each of the integration architectures by elaborating on the operational and control structures. Our performance analysis provides insight into QoS-rich next-generation optical-wireless converged networks.

Design and optimization of fiber optic small-cell backhaul based on an existing fiber-to-the-node residential access network

As the number of wireless users and per-user bandwidth demands continue to increase, both the vendor and carrier communities agree that wireless networks must evolve toward more dense deployments. So-called heterogeneous networks are a commonly proposed evolution, whereby existing macrocellular networks are supplemented with an underlay of small cells. The placement of new small-cell sites is typically determined based on various location-dependent factors such as radio propagation calculations, user densities, and measurements of congestion and demand. The backhaul network, which can account for a significant portion of the total cost of the deployment, is then designed in reaction to the placement of small cells. In contrast, we describe a design method that first considers the locations of existing fibered and powered facilities that might be leveraged to provide inexpensive backhaul. Naturally, such a method is only feasible if the carrier has a legacy local fiber network. This article describes an efficient fiber backhaul strategy for a small-cell network, which leverages facilities associated with an existing FTTN residential access network. Once potential small-cell sites are determined from among all FTTN remote terminals, optimization techniques are used to choose the most efficient subset of sites for maximum coverage, and to design the fiber backhaul architecture.

Design of cost-optimal passive optical networks for small cell backhaul using installed fibers [invited]

With the recent popularity of mobile data devices, the demand for mobile data traffic has grown rapidly as never before. Hence, service providers are trying to come up with cost-effective solutions to battle this ever increasing demand for bandwidth in their cellular networks. Deployment of a denser heterogeneous network, with a large number of small cells, has been identified as an effective strategy not only to satisfy this unabated growth in mobile data traffic but also to facilitate ubiquitous wireless access. While the cost associated with on-site small cell equipment is low in comparison with a typical macro cell, deployment of small cells opens a new set of challenges, especially in relation to expenditures and capacity requirements associated with the backhaul. In this paper we discuss an efficient small cell backhauling strategy that leverages existing fiber resourcesin a cost-optimal manner. In particular, we formulate an optimization framework for planning a cost-minimized backhaul for a small cell network, which is based on the deployment of passive optical networks on top of the existing infrastructure. We demonstrate the effectiveness of our method by using our optimization framework to design a cost-optimal backhaul for a small portion of a realistic backhaul network. Our results show that in comparison to the typical point-to-point fiber backhauling approach, our technique can halve the costs associated with small cell backhaul deployment.

Cost-Optimal Placement and Backhauling of Small-Cell Networks

The deployment of small cells has been identified as one of the future-proof solutions to cope with the increasing demand for higher data rate and ubiquitous access in mobile networks. However, providing a reliable and cost-effective backhaul connectivity for small cells has become a key challenge. It is identified that the cost efficiency of small-cell deployments can be improved by leveraging existing resources when planning the deployment. However, if not strategically planned the deployment, such an approach may compromise other requirements such as coverage and capacity. In this paper, we demonstrate how a small-cell network and its backhaul can be planned cost efficiently in scenarios where the existing fiber resources are sparsely located. To this end, we develop an optimization framework to minimize the deployment cost subject to a range of constraints that capture different network requirements such as the coverage and capacity. We demonstrate a practical example by using our model to plan a small-cell network and its backhaul, for a typical suburban area where existing fiber access locations are sparsely located. We also discuss the potential cost implications due to the stringency of different network requirements, by evaluating the optimal solutions for variety of deployment scenarios.

Architecture discovery enabled resource allocation mechanism for next generation optical-wireless converged networks

Optical-wireless convergence is identified as a promising solution to facilitate quality-of-service (QoS)-guaranteed, ubiquitous, and high-bandwidth access to end users. Different converged network architectures can be deployed depending on individual circumstances to achieve improved performance without compromising cost-effectiveness. However, with different network architectures, different resource allocation mechanisms are required to achieve the best performance. This is problematic in both the deployment and operational phases. In this paper, we propose an architecture discovery enabled resource allocation (ADERA) mechanism for the long term evolution (LTE)-gigabit Ethernet passive optical network (GEPON) converged network. The proposed ADERA is a self-adaptive algorithm ¿ it discovers the underlying architecture of the network by analyzing control signals and eventually evolves into an effective resource handling mechanism for the respective architecture. In addition, ADERA leverages inherited features of both the LTE network and GEPON in conjunction with the characteristics of their frame structures to improve the overall network performance. For example, ADERA is incorporated with a near-future traffic forecasting mechanism for efficient resource allocation. Using simulations, we evaluate the performance of our proposed ADERA algorithm and compare it against other existing resource allocation mechanisms. Our results indicate that ADERA achieves improved QoS performance in the converged network irrespective of the architecture used for the deployment.

Quality of service assurance in EPON-WiMAX converged network

We analyze the quality of service (QoS) performance of different traffic classes in optical-wireless converged networks when different resource handling mechanisms are used. We show that in order to achieve the optimum QoS performance in the EPON-WiMAX converged network for all traffic classes, a proper combination of a dynamic bandwidth allocation algorithm, an intra ONU-BS (integrated optical network unit and WiMAX base station) scheduling algorithm, and a QoS mapping mechanism need to be implemented. We propose such a combination that includes novel intra ONU-BS scheduling algorithm which improves the QoS performance of all traffic classes of an EPON-WiMAX converged network.

An Efficient Resource Allocation Mechanism for LTE---GEPON Converged Networks

Optical–wireless convergence is becoming popular as one of the most efficient access network designs that provides quality of service (QoS) guaranteed, uninterrupted, and ubiquitous access to end users. The integration of passive optical networks (PONs) with next-generation wireless access networks is not only a promising integration option but also a cost-effective way of backhauling the next generation wireless access networks. The QoS performance of the PON–wireless converged network can be improved by taking the advantages of the features in both network segments for bandwidth resources management. In this paper, we propose a novel resource allocation mechanism for long term evolution–Gigabit Ethernet PON (LTE–GEPON) converged networks that improves the QoS performance of the converged network. The proposed resource allocation mechanism takes the advantage of the ability to forecast near future packet arrivals in the converged networks. Moreover, it also strategically leverages the inherited features and the frame structures of both the LTE network and GEPON, to manage the available bandwidth resources more efficiently. Using extensive simulations, we show that our proposed resource allocation mechanism improves the delay and jitter performance in the converged network while guarantying the QoS for various next generation broadband services provisioned for both wireless and wired end users. Moreover, we also analyze the dependency between different parameters and the performance of our proposed resource allocations scheme.

QoS performance of next generation optical-wireless converged network and PON cycle length

Optical-wireless convergence is becoming one of the evolutionary technologies to provide quality-of-service (QoS) guaranteed ubiquitous access to end users. In this paper, we analyze the effect of GEPON cycle-length on the QoS performance of the GEPON-LTE converged network, when different resource handling mechanisms are used. The simulation results indicate that the influence of different cycle-lengths on the QoS performance varies depending on different traffic types and the resource handling mechanism used. We show that, this dependency can be reduced by introducing a unified resource handling mechanism which also improves the overall QoS performance of the converged network.

Energy consumption of next-generation optical-wireless converged networks

We compare three different plausible architectures for next-generation optical-wireless convergence in energy conservation viewpoint. Our analysis provides insight into QoS rich optical-wireless converged network architectures that preserve energy efficiency.

Hybrid fiber-wireless network: an optimization framework for survivable deployment

Abstract—Hybrid fiber-wireless (FiWi) networks, which benefit from high bandwidth and ubiquitous access of optical and wireless networks, have been identified as a promising technology candidate for next-generation broadband access. As various component/fiber failures may occur in hybrid FiWi networks, thus affecting huge numbers of end users, survivability has become one of the key important deployment considerations in such networks. This paper focuses on developing optimal network planning strategies to achieve survivable hybrid FiWi networks. In particular, to address the additional cost involved in deploying backup fibers in previously proposed redundancy strategies against distribution fiber failures, we propose the use of wireless routing through the ubiquitous wireless coverage of end users in a hybrid FiWi network. We present an optimization framework to optimally plan and deploy a survivable hybrid FiWi network, where traffic from an affected optical network unit (ONU) can be effectively rerouted to backup ONUs through wireless connections in the event of a distribution fiber failure. However, focusing only on the resilience of a network without considering its cost, and ignoring the resultant capacity, latency, and coverage under normal and protection operating conditions, is impractical. Our proposed framework therefore ensures maximum end-user coverage whilst satisfying survivability, connectivity, delay, and capacity constraints of the network, by optimizing the placement of passive optical splitters, ONUs, and wireless routers in conjunction with fiber and wireless connections. Moreover, we demonstrate the feasibility of our framework in the context of an urban deployment under different deployment scenarios. In particular, our results provide insight into how survivable FiWi networks can be deployed without compromising on the latency, coverage, and capacity requirements of such networks.