Access Networks

We present a model of energy consumption in IP networks. Using this model, we identify energy ldquohotspotsrdquo and estimate how energy consumption will grow with increasing network capacity. Todaypsilas Internet uses less than 1% of the available electricity supply. However, network energy consumption could grow substantially as access rates increase.

The power consumption of wireless access networks will become an important issue in the coming years. In this paper, the power consumption of base stations for mobile WiMAX, fixed WiMAX, UMTS, HSPA, and LTE is modelled and related to the coverage. A new metric, the power consumption per covered area P C area , is introduced, to compare the energy efficiency of the considered technologies for a range of bit rates. Assuming the model parameters are correct, the conclusions are then as follows. For a 5 MHz channel, UMTS is the most energy-efficient technology until a bit rate of 2.8 Mbps, LTE between 2.8 Mbps and 8.2 Mbps, fixed WiMAX between 8.2 Mbps and 13.8 Mbps and finally mobile WiMAX for bit rates higher than 13.8 Mbps. Furthermore, the influence of MIMO is investigated. For a 2x2 MIMO system, P C area decreases by 36 % for mobile WiMAX and by 23 % for HSPA and LTE compared to the SISO system, resulting in a higher energy efficiency. The power consumption model for base stations is used in the deployment tool GRAND (Green Radio Access Network Design) for green wireless access networks. GRAND uses a genetic based algorithm and is applied on an actual case for the Brussels Capital Region, showing the possibilities of energy-efficient planning.

This report focuses on the Access network implementation of a 5G small-cell communication system using Cognitive Radio. 5G systems are the next major wireless communications standard and Cognitive Radio is being heralded as a valid implementation method when the wireless communications industry finally concludes on a fifth generation standard. The project is concerned with implementing a Beyond-Next-Generation (5G) communications network based on Cognitive Radio. A functioning model is developed in matlab, the purpose of which is to show that Cognitive Radio based 5G systems will give acceptable Quality-of-Service and energy efficiency levels.
The Access network implementation of the system involves channel assignment for the access links which provide network access to mobile subscribers. Suitable channels to service call requests are determined based on cognition.
The system performance is evaluated by estimating the system blocking and dropping probabilities and the percentage of energy saved.

In this study, a optical passive networks system-based 2D-optical code division multiple access (OCDMA) wavelength division multiplexing (WDM) is proposed. For the uplink, 2D-prime hop system (PHS) codes and 2D-HC are employed. Nonetheless, a WDM scheme is used for the downlink. The system is firstly analysed and the performances are then provided in terms of signal-to-noise ratio (SNR) bit error rate (BER), Q-factor and optical power budget as function of optical received power. The authors show that the proposed system can reach 40 Gb/s with a good BER value <10 −10 when a vertical-cavity surface-emitting laser and an APD receiver are deployed in the optical network unit and optical line terminal, respectively. Moreover, it is shown that bit rate can be increased up to 150 Gb/s using 2D-HC codes for the uplink. Finally, power budget for 524 network subscribers is achieved showing a long PON distance up to 41 Km with a maximum throughput equal to 285.1 Gb/s/Km using an emitted average power equal to 15 dBm.

In a passive optical network with a hybrid wavelength division multiplexing time division multiple-access scheme, implementing reconfigurable wavelength assignment is complex; hence the need to determine the conditions for which the capacity improvements justify requiring reconfigurability over adopting a more inexpensive fixed wavelength assignment. Fixed and reconfigurable approaches to wavelength assignment are modeled and evaluated under nonstationary traffic conditions. The performance improvement is obtained in terms of bit rate gain relative to the nominal bandwidth and depends on the number of wavelength channels as well as the magnitude of the load offered by the optical network units. In addition, frame delay and frame loss in relation to the bit rate performance are obtained for Pareto and exponentially distributed traffic. Simulations show that when introducing reconfigurability, typical peak bit rate gains with respect to the fixed case are 17%, and maxima of 175% are potentially possible when traffic demands are particularly uneven.

Applications of non-blocking large-scale optical switches based on three-dimensional micro-electro-mechanical system (3D-MEMS) technology with small size and low power consumption are described for fiber-based broadband access networks. The low-loss and fast-switching 3D-MEMS switches offer remotely reconfigurable and automated operational solutions for access networks such as fiber management, preventative maintenance, monitoring, testing, and troubleshooting of a large number of end customers. Furthermore, the wavelength, data rate, and protocol-transparent nature of 3D-MEMS switches results in a future-proof optical distribution network design for future higher speed and higher capacity wavelength division multiplexing overlay upgrades over the passive optical network (PON). We show that large-scale 3D-MEMS switches deployed in PON environments can offer over an order of magnitude in capital and operational savings in comparison to manual patch panels (in deployed fiber hardware, real estate, and manual labor) with minimal impact on the overall network design.

Energy consumption in telecommunication networks has become a significant problem during the last few years. Many energy efficient mechanisms have been proposed and evaluated with respect to their impact on the overall network performance (e.g., delay, blocking probability, quality of transmission). Most of these mechanisms are based on the sleep mode functionality, i.e., a “low power ” state of network devices that can be utilized in low traffic conditions. On the other hand, a frequent switching between a working and a sleeping state may increase the probability of failures in a device, which in turn makes the operational cost related to fault reparation higher. This paper discusses how sleep mode-based energy saving mechanisms can impact the reliability performance of network equipment by pointing out several physical phenomena that may lead to an increase of the failure rate. In order to quantify such effects we propose a methodology that estimates to what extent energy savings ...

Radio access networks for future LTE/5G scenarios need to be designed so as to satisfy increasingly stringent requirements in terms of overall capacity, individual user performance, flexibility and power efficiency. This is triggering a major shift in the Telcom industry from statically sized, physically provisioned network appliances towards the use of virtualized network functions that can be elastically deployed within a flexible private cloud of network operators. However, a major issue in delivering strong QoS levels is the one to keep in check the temporal interferences among co-located services, as they compete in accessing shared physical resources. In this paper, this problem is tackled by proposing a solution making use of a real-time scheduler with strong temporal isolation guarantees at the OS/kernel level. This allows for the development of a mathematical model linking major parameters of the system configuration and input traffic characterization with the achieved performance and response-time probabilistic distribution. The model is verified through extensive experiments made on Linux on a synthetic benchmark tuned according to data from a real LTE packet processing scenario.

CREATE-NET's testbed is an open, service-oriented environment, implemented on a real-life city-wide communication infrastructure deployed in the city of Trento. Target user groups and users are integral part of the experimentation and take part in validation of the services implemented in the testbed. It spans the range of the most advanced communications technologies, starting from a wide area DWDM optical backbone, WiMAX & Wi-Fi wireless distribution/access networks, all the way to sensor networks and technologies for smart spaces. The testbed also serves as a model of a community network, planned for deployment in the Province of Trento. I.

Multihomed environments are getting increasingly common, especially for mobile users. mHIP was designed to provide secure multipath data transmission for the multihomed hosts and boost throughput of a single TCP connection by effectively distributing data over multiple available paths. In this paper we develop a TCP-friendly congestion control scheme for mHIP secure multipath scheduling solution. We enable two-level control over aggressiveness of the multipath flows to prevent stealing bandwidth from the traditional transport connections in the shared bottleneck. We demonstrate how to achieve a desired level of friendliness at the expense of inessential performance degradation. A series of simulations verifies that the proposed congestion control for mHIP meets the criteria of TCP-compatibility, TCP-equivalence and TCP-equal share, preserving friendliness to UDP and another mHIP traffic.

The paper presents a new approach for Bandwidth control in Broadband Access Networks, especially Digital Subscriber Line (DSL) and Cable Internet (DOCSIS) users. The basic idea is to have a broadband line to the server receiving all the incoming bandwidth. The approach is to have bandwidth division among various VLANs in a network connected via a switch to a centralized server. This approach can be implemented either in an institution where the amount of bandwidth to each department falling under one VLAN can be allocated proportional to the usage and requirements or in an industry where bandwidth needs to be allocated to various divisions. The concept of giving bandwidth according to the VLAN has been made to enhance security and ensuring that the traffic of one VLAN reaches that particular VLAN only. The basic idea is to have a broadband line to the server receiving all the incoming bandwidth. The server then queue the packets according to the VLAN id .The VLAN id of some department having paid for higher bandwidth or having more importance will be given higher priority at the server. All packets belonging to a particular VLAN will be queued in the same queue. The VLAN having higher precedence will have more of its packets sent than the other queues to ensure that the VLAN which was allocated higher bandwidth will receive that bandwidth. The idea is to have VLANs spread across multiple switch yet providing the proportionate bandwidth to each VLAN and also provide mobility to each member of VLAN. Some end users who are of interdisciplinary departments will be members of two or more VLANs.

Optical/wireless convergence has become of particular interest recently because a combined radio wireless and optical wired network has the potential to provide both mobility and high bandwidth in an efficient way. Recent developments of new radio access technologies such as the Long Term Evolution (LTE) and introduction of femtocell base stations open new perspectives in providing broadband services and applications to everyone and everywhere, but the instantaneous quality of radio channel varies in time, space and frequency and radio communication is inherently energy inefficient and susceptible to reflections and interference. On the other hand, optical fiber-based networks do not provide mobility, but they are robust, energy efficient, and able to provide both an almost unlimited bandwidth and high availability.

Abstract—We describe a formal approach to the analysis of security aspects of an identity federation protocol for web services in convergent networks. This network protocol was proposed by Telecom Italia as a solution to allow end users to access services on the web through different ...

The paper presents a new approach for Bandwidth control in Broadband Access Networks, especially Digital Subscriber Line (DSL) and Cable Internet (DOCSIS) users. The basic idea is to have a broadband line to the server receiving all the incoming bandwidth. The approach is to have bandwidth division among various VLANs in a network connected via a switch to a centralized server. This approach can be implemented either in an institution where the amount of bandwidth to each department falling under one VLAN can ...

Completely GPS-free positioning systems for wireless, mobile, ad-hoc networks typically stress on building a network-wide coordinate system. Such systems suffer from lack of mobility and high computational overhead. On the other hand, specialized hardware in GPS-enabled ...

Most of the IEEE 802.16e Mobile WiMAX scheduling proposals for real-time traffic using Unsolicited Grant Service (UGS) focus on the throughput and guaranteed latency. The delay jitter and the effect of burst overhead have not yet been investigated. This paper introduces a new technique called Swapping Min-Max (SWIM) for UGS scheduling that not only meets the delay constraint with optimal throughput, but also minimizes the delay jitter and burst overhead.

This paper presents a comprehensive techno-economic evaluation of two multimedia cases based on xDSL and HFC technologies, illustrating their respective merits and pitfalls, allowing the definition of a reasonable investment policy. The scenarios considered reflect the point of view of both dominant operators and new entrants. Techno-economic results are presented in terms of costs and revenues from the multimedia services, net present value (NPV), cash flows and pay-back periods. The business cases presented here were studied using the tool developed by European Project ACTS 226/OPTIMUM and ACTS 364/TERA. This study evaluates financial results for different upgrade scenarios trying to provide guidelines for future broadband implementation strategies. The sensitivity of the photonic and xDSL equipment to the total investment is analysed taking into account the present value of them and their cost evolution. The significance of this equipment to the success of a business case is presented and the cost breakdown is discussed.

In order to satisfy the increasing demand of wireless broadband multimedia services, much attention has been paid to the 60 GHz band where as much as 5 GHz of spectrum has been reserved. However, in the indoor environment, the propagation of signals at this millimeter wave band is strongly hindered by walls, people and their movement, furniture, etc. As a result, a mobile user might experience frequent loss of connection as the user moves from one cell to another. In this paper, we propose a flexible and cost-effective Radio-over-Fiber (RoF) based network architecture to support indoor networking at millimeter wave bands. To create sufficient overlap areas between cells and thus to ensure a seamless communication environment for mobile users, the concept of Extended Cell is introduced. We demonstrate the effectiveness of the proposed architecture with a detailed simulation study of an indoor scenario. Furthermore, we analyze the impact of the architecture on the performance of two popular state-of-the-art protocols, namely IEEE 802.11 and IEEE 802.16, to find which Medium Access Control (MAC) protocol is suitable for RoF networks.

Ethernet passive optical networks (EPONs) are designed to deliver services for numerous applications such as voice over Internet protocol, standard and high-definition video, video conferencing (interactive video), and data traffic. Various dynamic bandwidth allocation and intra-optical network unit (ONU) scheduling algorithms have been proposed to enable EPONs to deliver differentiated services for traffic with different quality of service (QoS) requirements. However, none of these protocols and schedulers can guarantee bandwidth for each class of service nor can they protect the QoS level required by admitted real-time traffic streams. In this paper, we propose the first framework for per-stream QoS protection in EPONs using a two-stage admission control (AC) system. The first stage enables the ONU to perform flow admission locally according to the bandwidth availability, and the second stage allows for global AC at the optical line terminal. Appropriate bandwidth allocation algorithms are presented as well. An event-driven simulation model is implemented to study the effectiveness of the proposed schemes in providing and protecting QoS.

Ethernet is becoming increasingly popular in metro and access networks due to the high bandwidth available at low cost. Nonetheless, native Ethernet lacks some features that are important for sophisticated network management; providing accurate knowledge on the physical topology is one of them. Therefore, automatic physical topology discovery in support of network management is essential in Ethernet networks. Former work either focused on Layer-3 topology discovery or only provided the active topology excluding the physical links inactivated by Rapid Spanning Tree Protocol [1]. This paper introduces a novel mechanism capable of automatically discovering the entire physical topology of Ethernet networks. Our algorithm collects information available even in low-cost offthe-shelf Ethernet switches and then calculates the physical topology of the entire network. This paper describes the method and its implementation in a testbed network for assessing the performance and the robustness of the mechanism.

This paper presents a comprehensive techno-economic evaluation of two multimedia cases based on xDSL and HFC technologies, illustrating their respective merits and pitfalls, allowing the definition of a reasonable investment policy. The scenarios considered reflect the point of view of both dominant operators and new entrants. Techno-economic results are presented in terms of costs and revenues from the multimedia services, net present value (NPV), cash flows and pay-back periods. The business cases presented here were studied using the tool developed by European Project ACTS 226/OPTIMUM and ACTS 364/TERA. This study evaluates financial results for different upgrade scenarios trying to provide guidelines for future broadband implementation strategies. The sensitivity of the photonic and xDSL equipment to the total investment is analysed taking into account the present value of them and their cost evolution. The significance of this equipment to the success of a business case is presented and the cost breakdown is discussed.

In order to satisfy the increasing demand of wireless broadband multimedia services, much attention has been paid to the 60 GHz band where as much as 5 GHz of spectrum has been reserved. However, in the indoor environment, the propagation of signals at this millimeter wave band is strongly hindered by walls, people and their movement, furniture, etc. As a result, a mobile user might experience frequent loss of connection as the user moves from one cell to another. In this paper, we propose a flexible and cost-effective Radio-over-Fiber (RoF) based network architecture to support indoor networking at millimeter wave bands. To create sufficient overlap areas between cells and thus to ensure a seamless communication environment for mobile users, the concept of Extended Cell is introduced. We demonstrate the effectiveness of the proposed architecture with a detailed simulation study of an indoor scenario. Furthermore, we analyze the impact of the architecture on the performance of two popular state-of-the-art protocols, namely IEEE 802.11 and IEEE 802.16, to find which Medium Access Control (MAC) protocol is suitable for RoF networks.

Completely GPS-free positioning systems for wireless, mobile, ad-hoc networks typically stress on building a network-wide coordinate system. Such systems suffer from lack of mobility and high computational overhead. On the other hand, specialized hardware in GPS-enabled nodes tends to increase the solution cost. A number of GPS free position based routing algorithms have been studied by the authors before proposing a new positioning framework in this paper. The proposed positioning framework is characterized by using only a handful of GPS enabled nodes. Lower dependence on specialized GPS hardware reduces the total cost of implementing the framework. A new location aided routing protocol called Location Aided Cluster Based Energy-efficient Routing (LACBER) has been proposed in the paper. Simulation results show that using the proposed positioning framework, LACBER turns out to be efficient in lowering mean hop and hence in utilizing the limited energy of mobile nodes

Most of the IEEE 802.16e Mobile WiMAX scheduling proposals for real-time traffic using Unsolicited Grant Service (UGS) focus on the throughput and guaranteed latency. The delay jitter and the effect of burst overhead have not yet been investigated. This paper introduces a new technique called Swapping Min-Max (SWIM) for UGS scheduling that not only meets the delay constraint with optimal throughput, but also minimizes the delay jitter and burst overhead.

The Up/Down Link UDL of a Low Earth Orbit LEO satellite constellation is a scarce radio resource that needs to be shared efficiently between many users with different needs. A suitable Connection Admission Control CAC policy is required. In our study we assume that the network handles three types of calls: real time (voice) calls with strict constraints over the delay and the bandwidth, non real time (data) calls delay tolerant but with bandwidth guarantees requirements and Best Effort calls with no guarantees requirements. In order to ensure priorities are respected, we use an "enhanced trunk reservation policy" in order to derive the Resources Allocation RA. A differentiated RA scheme is proposed, associated with queuing for the lower priority calls. Different unity bandwidths are associated with calls depending on their requirements. The analytical markovian model is first derived, then the differentiated RA model is compared with two cases of bandwidth granularity choice. Impact of non markovian laws is studied using simulation.

The foundations for the definition of the network of the future should be based on a correct user and community characterizations to minimize the fragmentation of the experiences during the global interactions with information communication infrastructures. This paper describes some of the complex objectives and main challenges that telecommunication solution and services have to deal with in order to respect both specific requirements of global user interactions, habits and personalization, and framework requirements about green environments.

A new all-optical access-metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access-metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access-metro interface and architectures. Index Terms-Dynamic bandwidth allocation (DBA), metropolitan area network (MAN), optical burst switching (OBS), passive optical networks (PONs), quality of service (QoS).

IP multihoming is a networking concept with a deceptively simple definition in theory. In practice, however, multihoming has proved difficult to implement and optimize for. Moreover, it is a concept, which, once adopted in the core Internet architecture, has a significant impact on operation and maintenance. A trivial definition of multihoming would state that an end-node or an end-site has multiple first-hop connections to the network. In this paper, we survey and summarize in a comprehensive manner recent developments in IP multihoming. After introducing the fundamentals, we present the architectural goals and system design principles for multihoming, and review different approaches. We survey multihoming support at the application, session, transport, and network layers, covering all recent proposals based on a locator/identifier split approach. We critically evaluate multihoming support in these proposals and detail recent developments with respect to multihoming and mobility management.

IP multihoming is a networking concept with a deceptively simple definition in theory. In practice, however, multihoming has proved difficult to imple- ment and optimize for. Moreover, it is a concept, which, once adopted in the core Internet architecture, has a significant impact on operation and maintenance. A trivial definition of multihoming would state that an end-node or an end-site has multiple first-hop con- nections to the network. In this paper, we survey and summarize in a comprehensive manner recent develop- ments in IP multihoming. After introducing the funda- mentals, we present the architectural goals and system design principles for multihoming, and review different approaches. We survey multihoming support at the ap- plication, session, transport, and network layers, cover- ing all recent proposals based on a locator/identifier split approach. We critically evaluate multihoming support in these proposals and detail recent developments with respect to multihoming and mobility management.

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Inspired by a problem regarding cable access networks, we consider a two station tandem queue with Poisson arrivals. At station 1 we operate a gate mechanism, leading to batch arrivals at station 2. Upon arrival at station 1, customers join a queue in front of a gate. Whenever all customers present at the service area of station 1 have received service, the gate before as well as a gate behind the service facility open. Customers leave the service area and enter station 2 (as a batch), while all customers waiting at the gate in front of station 1 are admitted into the service area. For station 1 we analyse the batch size and the time between two successive gate openings, as well as waiting and sojourn times of individual customers for different service disciplines. For station 2, we investigate waiting times of batch customers, where we allow that service times may depend on the size of the batch and also on the interarrival time. In the analysis we use Wiener-Hopf factorization techniques for Markov modulated random walks.

The impact of wholesale prices is examined in a context where the end customer access both free content and pay-per-use content, delivered by two different providers through a common network provider. We formulate and solve the game between the network provider and the pay-per-use content provider, where both use the price they separately charge the end customer with as a leverage to maximize their profits. In the neutral case (the network provider charges equal wholesale prices to the two content providers), the benefits coming from wholesale price reductions are largely retained by the pay-per-use content provider. When the free content provider is charged more than its pay-per-use competitor, both the network provider and the pay-per-use content provider see their revenues increase, while the end customer experiences a negligible reduction in the retail price.

This paper focuses on the competitively optimal power-control, signal-shaping and interference mitigation for wireless mesh networks composed by Multiple-Antenna noncooperative transmit terminals and a base station affected by spatially colored Multi-Access Interference (MAI). The target is the competitive maximization of the information throughput of the uplink of each link active over the network. For this purpose, the MAIimpaired network is modeled as a noncooperative strategic game. Specifically, the main contribution of this paper may be so summarized. First, we consider a power-control, signal-shaping and interference mitigation algorithms allowing the implementation of asynchronous Space-Division Multiple Access (SDMA) strategies able to guarantee the competitive maximization of the users' rate under both Quality of Service (QoS) guaranteed and QoS contracted access policies. Second, we give evidence that the developed SDMA outperforms (in terms of aggregate throughput) the conventional orthogonal ones, specially in operating scenarios affected by strong MAI. Third, we consider the multiple access capacity that is the maximum number of users able to be connected with a requested level of QoS in terms of rate.

This paper formulates a distributed cross layer channel allocation-power control problem for an ad-hoc cognitive radio network in dynamic spectrum access and applies a localized variation of the island Genetic Algorithm (iGA) to solve this problem. For comparison purposes, we also implement the standard iGA, which works with global information, and compare it to the localized iGA to analyze the effect of working with partial knowledge on network performance. Simulation results demonstrate that the localized iGA results in efficient spectrum allocation.

ABSTRACT With the large number of access technologies and the emergence of user mobility, the need to &amp;quot;access the world&amp;quot;, anywhere and anytime has gained a significant importance. It is essential to ensure the quality of the services when moving between access networks and technologies in a transparent manner. This paper presents a new architecture that enables seamless handovers in wireless heterogeneous environments. Towards this aim, the proposed architecture combines the MIPv6 mobility management protocol, the IEEE 802.21 Media Independent Handover (MIH) framework, and a mobility control entity responsible for controlling the handover decisions in a make-before-break approach. In order to validate and evaluate this new solution, a real testbed was developed, combining Wi-Fi, WiMAX and 3G technologies. The results obtained with this experimental platform cover the analysis of the handover processes, and important aspects as the handover performance, QoS and QoE of the services while handover is taking place. The results show the significant benefits of the proposed approach.