Chamil Jayasundara

Energy efficient content distribution for VoD services

The energy consumption of VoD services arising from storage and transport of video contents stored in different content placement locations is investigated. Our results provide insight into content placement strategies that improve energy efficiency.

Improving Energy Efficiency of Video on Demand Services

The energy consumption of the Internet is anticipated to be one of the main contributors to global energy consumption in the coming decades. As a result, renewed attention has been given to the energy efficient design and operation of network services. The video on demand (VoD) service is expected to be one of the most prominent services through the Internet in the near future. Due to the enormous energy consumption arising from storage and transport of movies, energy efficient design and operation of VoD systems are important considerations. In this paper, we formulate energy consumption models to analyze the energy consumption arising from storage and transport of movies in VoD systems. We consider five strategic content placement locations located at different levels of the video distribution network and we comparatively analyze the energy consumption of storage and transport when the movies are stored and delivered from these locations. Moreover, we derive thresholds for movie request arrival rates which determine whether replication of a movie in a given content placement location is energy efficient and whether turning ON a set of content storages located at a particular level of the network is energy efficient. By numerically analyzing the energy consumption models, we show that the energy efficiency of VoD services can be significantly improved by delivering movies from the most energy efficient content placement locations in the network. We show that this can be achieved by designing and operating VoD systems based on our derived thresholds which optimize the energy efficiency of VoD services for all user request arrival rates.

Popularity-Aware Caching Algorithm for Video-on-Demand Delivery over Broadband Access Networks

Video on Demand (VoD) service is regarded as one of the most promising services over increasingly deployed next generation broadband access networks. The distributed server architecture, in which the popular content is cached at a location closer to the viewer, is a widely used methodology to optimize the transport capacity of VoD delivery. However, due to the dynamic (change with time) nature of movie popularity distribution, identifying the popular content and updating the cache servers accordingly is not straightforward. In this paper, using a novel caching architecture for Passive Optical Networks (PON), we discuss the need for a fast caching algorithm that can respond to time changing movie popularity distribution, and we propose a novel Last-k caching algorithm, which identifies the popular content using the most recent statistics. The proposed algorithm estimates movie popularity using most recent inter-arrival times of movie requests and updates the cache accordingly such that the most popular content at any given time would reside in the cache. Simulations indicate that the proposed algorithm out-performs existing algorithms by effectively responding to the dynamic nature of movie popularity distribution.

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.

Localized P2P VoD Delivery Scheme with Pre-Fetching for Broadband Access Networks

Video on Demand (VoD) service has become an increasingly popular service in recent years as a result of the rapid deployment of Fiber-to-the-Home networks. Due to its enormous bandwidth and stringent quality of service requirements, deploying an efficient and scalable VoD service still remains a challenge. In this paper, we propose a peer-to peer (P2P) VoD distribution scheme for PONs in which the P2P delivery is localized to within the same access network and in which a selected set of movies is pre-fetched into the customer premises equipment during off-peak hours. The proposed delivery scheme mitigates the load from the VoD server by exploiting the participation of the customer equipment in VoD distribution. In turn, this optimizes bandwidth consumption of the VoD service in both core and metro networks as the P2P video traffic is localized within the access network. We formulate movie pre-fetching as an optimization problem which determines the number of copies of each movie to be pre-fetched, and we propose a heuristic algorithm to solve it. Using simulations we show that our proposed replication algorithm performs much better than existing popularity based replication algorithm that has been proposed for similar purposes. Moreover, we show that our proposed delivery scheme effectively reduced the server load in busy hours while having high but random server load reduction in off-peak hours of service.

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.

Energy Efficient Delivery Methods for Video-Rich Services over Next Generation Broadband Access Networks

We present energy consumption models of video-on-demand (VoD) services delivered through newly proposed localized hybrid peer-to-peer (P2P) and localized peer-assisted patching with multicast video delivery methods over optical access networks. In this paper, we demonstrate through simulations that the localized peer-assisted patching with multicast video delivery method consumes the lowest network transport energy for popular VoD channels while localized hybrid P2P method consumes the lowest network transport energy for less popular channels. Nevertheless, both schemes outperform the conventional server centric content distribution network in term of overall network energy consumption.

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.

Distributed storage solutions for video-rich services over next generation access networks

We investigate the strategic placement of distributed storage solutions within the broadband access boundary to reduce energy consumption arising from storage and transport of VoD services whilst maximizing downstream transport capacity.