Showing papers on "Broadband networks published in 2011"
TL;DR: This article introduces a millimeter-wave mobile broadband (MMB) system as a candidate next generation mobile communication system and demonstrates the feasibility for MMB to achieve gigabit-per-second data rates at a distance up to 1 km in an urban mobile environment.
Abstract: Almost all mobile communication systems today use spectrum in the range of 300 MHz-3 GHz. In this article, we reason why the wireless community should start looking at the 3-300 GHz spectrum for mobile broadband applications. We discuss propagation and device technology challenges associated with this band as well as its unique advantages for mobile communication. We introduce a millimeter-wave mobile broadband (MMB) system as a candidate next generation mobile communication system. We demonstrate the feasibility for MMB to achieve gigabit-per-second data rates at a distance up to 1 km in an urban mobile environment. A few key concepts in MMB network architecture such as the MMB base station grid, MMB interBS backhaul link, and a hybrid MMB + 4G system are described. We also discuss beamforming techniques and the frame structure of the MMB air interface.
2,487 citations
18 Jul 2011
TL;DR: An overview of the technological advances in millimeter-wave circuit components, antennas, and propagation that will soon allow 60-GHz transceivers to provide multigigabit per second (multi-Gb/s) wireless communication data transfers in the consumer marketplace is presented.
Abstract: This tutorial presents an overview of the technological advances in millimeter-wave (mm-wave) circuit components, antennas, and propagation that will soon allow 60-GHz transceivers to provide multigigabit per second (multi-Gb/s) wireless communication data transfers in the consumer marketplace. Our goal is to help engineers understand the convergence of communications, circuits, and antennas, as the emerging world of subterahertz and terahertz wireless communications will require understanding at the intersections of these areas. This paper covers trends and recent accomplishments in a wide range of circuits and systems topics that must be understood to create massively broadband wireless communication systems of the future. In this paper, we present some evolving applications of massively broadband wireless communications, and use tables and graphs to show research progress from the literature on various radio system components, including on-chip and in-package antennas, radio-frequency (RF) power amplifiers (PAs), low-noise amplifiers (LNAs), voltage-controlled oscillators (VCOs), mixers, and analog-to-digital converters (ADCs). We focus primarily on silicon-based technologies, as these provide the best means of implementing very low-cost, highly integrated 60-GHz mm-wave circuits. In addition, the paper illuminates characterization techniques that are required to competently design and fabricate mm-wave devices in silicon, and illustrates effects of the 60-GHz RF propagation channel for both in-building and outdoor use. The paper concludes with an overview of the standardization and commercialization efforts for 60-GHz multi-Gb/s devices, and presents a novel way to compare the data rate versus power efficiency for future broadband devices.
907 citations
15 Aug 2011
TL;DR: This first study of network access link performance measured directly from home gateway devices using longitudinal measurements from nearly 4,000 gateway devices across 8 ISPs from a deployment of over 4,200 devices yields many important findings about the characteristics of existing access networks.
Abstract: We present the first study of network access link performance measured directly from home gateway devices. Policymakers, ISPs, and users are increasingly interested in studying the performance of Internet access links. Because of many confounding factors in a home network or on end hosts, however, thoroughly understanding access network performance requires deploying measurement infrastructure in users' homes as gateway devices. In conjunction with the Federal Communication Commission's study of broadband Internet access in the United States, we study the throughput and latency of network access links using longitudinal measurements from nearly 4,000 gateway devices across 8 ISPs from a deployment of over 4,200 devices. We study the performance users achieve and how various factors ranging from the user's choice of modem to the ISP's traffic shaping policies can affect performance. Our study yields many important findings about the characteristics of existing access networks. Our findings also provide insights into the ways that access network performance should be measured and presented to users, which can help inform ongoing broader efforts to benchmark the performance of access networks.
353 citations
TL;DR: The design of a quality-of-service (QoS) aware packet scheduler for real-time downlink communications is considered, and a novel two-level scheduling algorithm is conceived based on discrete-time linear control theory.
Abstract: Long-term evolution represents an emerging technology that promises a broadband and ubiquitous Internet access. But several aspects have to be considered for providing effective multimedia services to mobile users. In particular, in this work, we consider the design of a quality-of-service (QoS) aware packet scheduler for real-time downlink communications. To this aim, a novel two-level scheduling algorithm is conceived. The upper level exploits an innovative approach based on discrete-time linear control theory. Instead, at the lower level, a proportional fair scheduler has been properly tailored to our purposes. The performance and the complexity of the proposed scheme have been evaluated both theoretically and by using simulations. A comparison with recently proposed scheduling strategies has been also presented, considering several network conditions and real-time multimedia flows. Particular attention has been devoted to the evaluation of the quality-of-experience (QoE) provided to end users. Results have clearly shown that the proposed approach is able to greatly outperform the existing ones especially in the presence of real-time video flows.
254 citations
TL;DR: A channel model for broadband indoor Power Line Communications (PLC) is presented and the structure has been simplified to derive a parametric model that still preserves the essential behavior of these channels in the HF band (up to 30 MHz).
Abstract: In this article, a channel model for broadband indoor Power Line Communications (PLC) is presented and discussed. The modeling approach is based on the physical structure of the electrical networks inside homes and small offices. The structure has been simplified to derive a parametric model that still preserves the essential behavior of these channels in the HF band (up to 30 MHz). The model provides realistic channels by setting values to a reduced number of physical parameters. In addition, statistical distributions for such parameters that allow generating ensembles of random channels are suggested. The validity of the generated channels is assessed by comparing their behavior to the one of channels measured at several indoor power networks. Hence, this model can be employed to estimate the performance of transmission techniques on PLC channels, to aid in the design of PLC systems or to make prototype conformance tests.
185 citations
TL;DR: This article examines the characteristics of HTTP traffic generated by millions of wireless users across one of the world's largest 3G cellular networks and explores the potential of forward caching.
Abstract: Recent studies have shown that in the wired broadband world, caching of HTTP objects results in substantial savings in network resources. What about cellular networks? This article examines the characteristics of HTTP traffic generated by millions of wireless users across one of the world's largest 3G cellular networks and explores the potential of forward caching. You can easily use the simple cost model provided here to determine the cost-benefit trade-offs for your own cellular network settings. This is the first large-scale caching analysis for cellular networks.
176 citations
TL;DR: It becomes obvious that home networks consume the largest share of energy in TC networks, and highest energy consumption shares are observed in the fixed and mobile access networks with a huge number of distributed network elements in the field.
Abstract: In this study, energy consumption of a universal network operator's broadband telecommunication (TC) network, including the home networks that are required for the use of services over a period of approximately one decade is predicted, whereby it is assumed that no measures for an energy-efficiency increase are taken. It becomes obvious that home networks consume the largest share of energy in TC networks. Concerning the network sections under the responsibility of network operator, highest energy consumption shares are observed in the fixed and mobile access networks with a huge number of distributed network elements in the field. The highest energy consumption growth rates are foreseen in the data centers and IP backbone networks. Methods for reducing energy consumption are being classified and metrics for energy-related assessment of networks are compared. Furthermore, challenges and opportunities for energy-related improvements are discussed with respect to different network sections. A projection into the future shows high-energy-saving potential when combining different energy-reducing methods, such as load-adaptive networking and energy-aware system design. A brief view on related standardization activities shows high interest of standardization bodies in energy consumption of TC networks and confirms its current importance.
170 citations
03 May 2011
TL;DR: This paper reason why wireless community should start looking at 3–300GHz spectrum for mobile broadband applications as well as its unique advantages such as spectrum availability and small component sizes for mobile applications.
Abstract: Almost all cellular mobile communications including first generation analog systems, second generation digital systems, third generation WCDMA, and fourth generation OFDMA systems use Ultra High Frequency (UHF) band of radio spectrum with frequencies in the range of 300MHz-3GHz. This band of spectrum is becoming increasingly crowded due to spectacular growth in mobile data and other related services. The portion of the RF spectrum above 3GHz has largely been uxexploited for commercial mobile applications. In this paper, we reason why wireless community should start looking at 3–300GHz spectrum for mobile broadband applications. We discuss propagation and device technology challenges associated with this band as well as its unique advantages such as spectrum availability and small component sizes for mobile applications.
167 citations
15 Aug 2011
TL;DR: This paper proposes four requirements for slicing home networks: bandwidth and traffic isolation between slices, independent control of each slice, and the ability to modify and improve the behavior of a slice.
Abstract: Despite the popularity of home networks, they face a number of systemic problems: (i)Broadband networks are expensive to deploy; and it is not clear how the cost can be shared by several service providers; (ii) Home networks are getting harder to manage as we connect more devices, use new applications, and rely on them for entertainment, communication and work|it is common for home networks to be poorly managed, insecure or just plain broken; and (iii) It is not clear how home networks will steadily improve, after they have been deployed, to provide steadily better service to home users.In this paper we propose slicing home networks as a way to overcome these problems. As a mechanism, slicing allows multiple service providers to share a common infrastructure; and supports many policies and business models for cost sharing. We propose four requirements for slicing home networks: bandwidth and traffic isolation between slices, independent control of each slice, and the ability to modify and improve the behavior of a slice. We explore how these requirements allow cost-sharing, outsourced management of home networks, and the ability to customize a slice to provide higher-quality service. Finally, we describe an initial prototype that we are deploying in homes.
144 citations
Patent•
29 Apr 2011
TL;DR: In this article, a method and system for creating vertical search engines with cloud computing networks is presented. But, the method is limited to the vertical search engine infrastructure used by searchers by providing vertical electronic information using less bandwidth and less processing cycles.
Abstract: A method and system for creating vertical search engines with cloud computing networks The cloud computing networks include a cloud communications network using public networks, private networks, community networks and hybrid networks The cloud communications network provides on-demand vertical search services, broadband network access, resource pooling, rapid elasticity and measured electronic services for vertical search engines The method and system dramatically improve a vertical search engine infrastructure used by searchers by providing vertical electronic information using less bandwidth and less processing cycles via the cloud communications network than via a non-cloud communications network Custom vertical search engines can be created by a user with QR bar codes and other types of bar codes and other types of custom information
122 citations
15 Apr 2011
TL;DR: This tutorial paper provides a comprehensive overview on the recent development in broadband wireless communications for high speed trains, starting with the introduction of the two-hop network structure, radio-over-fiber (RoF) based cell planning is described in detail.
Abstract: This tutorial paper provides a comprehensive overview on the recent development in broadband wireless communications for high speed trains. Starting with the introduction of the two-hop network structure, radio-over-fiber (RoF) based cell planning is described in detail. Moreover, based on the analysis of differences between conventional cellular systems and the one for high speed trains, promising techniques are recommended to improve the performance of handover, which is one of the main challenges in high speed train communications. Finally, in order to combat the fast fading caused by the high mobility, robust algorithms are needed in physical layer signal processing, including synchronization, channel estimation, modulation/demodulation, and so on.
TL;DR: In this article, the authors formulated an analytical framework for resource allocation in a downlink orthogonal frequency-division multiple access (OFDMA)-based broadband network with coexistence of secure users (SUs) and normal users (NUs).
Abstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink orthogonal frequency-division multiple access (OFDMA)-based broadband network with coexistence of secure users (SUs) and normal users (NUs). The SUs require secure data transmission at the physical layer while the NUs are served with conventional best-effort data traffic. The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NUs while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NUs follows the conventional water-filling principle, the power allocation for SUs depends on both its own channel gain and the largest channel gain among others. We also develop a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU and secrecy rate for SU at different power consumptions.
TL;DR: An analytical framework for resource allocation in a downlink orthogonal frequency-division multiple access (OFDMA)-based broadband network with coexistence of secure users (SUs) and normal users (NUs), and develops a suboptimal algorithm to reduce the computational cost.
Abstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink OFDMA-based broadband network with coexistence of secure users (SU) and normal users (NU). The SU's require secure data transmission at the physical layer while the NU's are served with conventional best-effort data traffic. The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NU's while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NU's follows the conventional water-filling principle, the power allocation for SU's depends on both its own channel gain and the largest channel gain among others. We also develop a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU and secrecy rate for SU at different power consumptions.
07 May 2011
TL;DR: It is argued that tools like this can educate and empower consumers by making broadband speeds and sources of slow-downs more visible, and design implications for future tools are provided.
Abstract: With widespread broadband adoption, more households report experiencing sub-optimal speeds. Not only are slow speeds frustrating, they may indicate consumers are not receiving the services they are paying for from their internet service providers. Yet, determining the speed and source of slow-downs is difficult because few tools exist for broadband management. We report on results of a field trial with 10 households using a visual network probe designed to address these problems. We describe the results of the study and provide design implications for future tools. More importantly, we argue that tools like this can educate and empower consumers by making broadband speeds and sources of slow-downs more visible.
TL;DR: It is proposed that wireless network access be shared in a peer-to-peer, reciprocal manner, so that ubiquitous broadband Internet access can be achieved at a low cost, at least in metropolitan areas where there is abundant wireless coverage, providing an inexpensive alternative to broadband cellular services.
Abstract: Low-cost wireless LAN equipment operating in unlicensed spectrum has revolutionized local area communications, introducing novel schemes for open wireless connectivity and even new business models The ease of deployment of Wi-Fi has made it ubiquitous in densely populated urban areas, and it was just a matter of time before wireless communities emerged Using inexpensive wireless technology to communicate, autonomous wireless internetworks have been built, offering a variety of broadband services Based on our own experience participating in one of the largest wireless communities worldwide, the Athens Wireless Metropolitan Network, we attempt to explain their structure and mechanisms, study the reasons for their emergence and growth, and predict their future evolution We expect that future wireless communities will be oriented toward providing broadband access to nomadic users To this end, we have proposed that wireless network access be shared in a peer-to-peer, reciprocal manner Thus, ubiquitous broadband Internet access can be achieved at a low cost, at least in metropolitan areas where there is abundant wireless coverage, providing an inexpensive alternative to broadband cellular services
TL;DR: In this article, the authors present the first study of network access link performance measured directly from home gateway devices, which is a first step towards measuring the performance of I2I links.
Abstract: We present the first study of network access link performance measured directly from home gateway devices. Policymakers, ISPs, and users are increasingly interested in studying the performance of I...
03 May 2011
TL;DR: A millimeter-wave mobile broadband system that utilizes frequencies in the 3–300 GHz spectrum as a candidate for next generation mobile communication and demonstrates the feasibility of using millimeter waves to provide Giga bps data rate at a distance up to 1 km for mobility up to 350 kmph.
Abstract: Evolution beyond 4G (LTE and mobile WiMAX) is crucial in keeping up with the exponential growth of mobile data traffic. In this paper, we describe a millimeter-wave mobile broadband (MMB) system that utilizes frequencies in the 3–300 GHz spectrum as a candidate for next generation mobile communication. A few key concepts in MMB network architecture such as the MMB inter-BS backhaul link, MMB base station grid, and hybrid MMB + 4G system are described. We demonstrate the feasibility of using millimeter waves to provide Giga bps data rate at a distance up to 1 km for mobility up to 350 kmph. We also discuss a few aspects of MMB air interface design such as beamforming, multiple access, and adaptive modulation and coding.
Patent•
20 Apr 2011
TL;DR: A broadband local area data network uses coaxial cable wiring for interconnection of terminal devices as discussed by the authors, which is used to overcome channel impairments and provide a path for terminal devices to transmit to and receive from other terminal devices.
Abstract: A broadband local area data network uses coaxial cable wiring for interconnection of terminal devices. Orthogonal frequency division multiplexing (OFDM) with bit loading is used to overcome channel impairments and provide a path for terminal devices to transmit to and receive from other terminal devices. Probe messages are sent between devices to characterize the communication channel and determine optimum bit loading. The data network shares the cable spectrum with other services and uses frequency bands not used by other services. Adaptive power control can be used to maintain signal to noise ratio in a communication between terminal devices. Frequency coordination can be used to avoid interference between the LAN communications and other services transmitted on the cable.
29 Sep 2011
TL;DR: A solution for frame accurate synchronization of hybrid media components used to compose personalized second screen TV services is described, which enables content components from distributed sources to be synchronously rendered on multiple terminals, even after transport over broadcast and broadband networks using different protocols and timing models.
Abstract: The combined use of broadcast and broadband networks offers the perspective of efficient delivery of a wide range of personalized TV services. Such services are particularly compelling when related content is simultaneously rendered on a personal terminal and on a TV set. As media components are transported separately over different networks, and delivered to different devices, there is a need for a technique to assure their accurate temporal alignment. This paper describes a solution for frame accurate synchronization of hybrid media components used to compose personalized second screen TV services. The approach enables content components from distributed sources to be synchronously rendered on multiple terminals, even after transport over broadcast and broadband networks using different protocols and timing models. An evaluation system has been built showing accurate lip-sync for an on-demand personalized soundtrack consumed on an IP connected handheld terminal in conjunction with broadcast video on a TV set.
TL;DR: In this article, a multimode/multiband envelope tracking (ET) transmitter consisting of a hybrid switching amplifier (HSA) and a broadband saturated power amplifier (PA) is developed for operation across 1.3 to 2.7 GHz.
Abstract: A multimode/multiband envelope tracking (ET) transmitter consisting of a hybrid switching amplifier (HSA) and a broadband saturated power amplifier (PA) is developed for operation across 1.3 to 2.7 GHz. For the various standard signals with different bandwidth (BW) and peak-to-average power ratio, the HSA efficiently provides supply signals to the PA by changing the reference value of the hysteresis comparator. The saturated amplifier employs the nonlinear output capacitor to shape the voltage waveform, resulting in the half-sinusoidal or rectangular waveform. Since the nonlinear capacitor generates large out-of-phased second harmonic component with small higher order harmonics, the voltage shaping is mainly carried out by the capacitor and slightly supported by the harmonic loading circuit. Thus, with the harmonic load higher than that of output capacitor, the saturated amplifier can operate with high efficiency. This characteristic enables the saturated PA to operate with broadband characteristic and high efficiency because the design is mainly focused on the fundamental matching problem while the harmonics can be easily kept out of a low efficiency region through the subsequent optimization of the matching circuit. The broadband saturated PA is implemented based on load/source-pull methodology. The broadband matching networks for the high efficiency are synthesized using the simplified real frequency technique. For the BW from 1.3 to 2.7 GHz (70% fractional BW), the measured output power, drain efficiency, and power-added efficiency (PAE) performances are between 39.8-42.0 dBm, 55.8-69.7%, and 51.2-65.3%, respectively. The multimode/multiband ET transmitter with the designed broadband saturated PA is demonstrated at 1.8425-GHz long-term evolution (LTE), 2.14-GHz wideband code division multiple access (WCDMA), and 2.6-GHz mobile world wide interoperability for microwave access (m-WiMAX) applications. This transmitter delivers a PAE of 32.16, 37.24, and 28.75% for LTE, WCDMA, and m-WiMAX applications.
TL;DR: By shortening the lastmile communication link and lowering the power consumption, BWA-FMDA represents a viable green wireless access solution and is capable of enhancing spectral efficiency of the network through coordinated multipoint transmissions at the femtocell scale.
Abstract: We introduce a novel last-mile architecture that integrates the advantages of a distributed antenna system with centralized processing capability, connected through an optical fiber medium. The proposed broadband wireless access with fiber-connected massively distributed antenna system (BWA-FMDA) is capable of enhancing spectral efficiency of the network through coordinated multipoint transmissions at the femtocell scale. Furthermore, by shortening the lastmile communication link and lowering the power consumption, BWA-FMDA represents a viable green wireless access solution. Through our detailed and extensive simulation results, we demonstrate the potentially superior performance of BWA-FMDA in comparison with micro base station and femtocell deployments.
Patent•
30 Aug 2011
TL;DR: In this paper, a system and method supporting the advertising of extended network access to multimedia services via a broadband access gateway is described, in which the gateway determines available media-related services, and transmits information about those services to an access device that may comprise, for example, a mobile multimedia handset, a personal digital assistant, and a personal computer.
Abstract: A system and method supporting the advertising of extended network access to multimedia services via a broadband access gateway is disclosed A representative embodiment of the present invention may comprise a wireless interface and may be capable of exchanging multimedia communication between the wireless interface and a broadband network The gateway may determine available media-related services, and may transmit information about those services to an access device that may comprise, for example, a mobile multimedia handset, a personal digital assistant, and a personal computer The access device may notify a user of the availability of the media-related services using visual and/or audible means The gateway may receive from the access device capability and/or subscriber related information, and the gateway may transmit service information based upon the capability and/or subscriber-related information
05 Jun 2011
TL;DR: A critical review of the term's utilization and operationalization in related fields is performed and the results demonstrate that acceptability is a relevant and useful concept that also features a consistent mapping between subjects' binary acceptance and ordinal satisfaction ratings, even across application scenarios as different as web browsing and file downloads.
Abstract: Due to the accelerating uptake of mobile broadband services, Quality of Experience (QoE) assessment and optimization for wireless networks has become a topic of vital importance. In this field, subjective quality evaluation methods based on MOS (Mean Opinion Score) are the most widely used approaches for understanding and measuring perceived performance. However, while these methods have been proven to reliably quantify users' degrees of satisfaction, they do not sufficiently address the following important question: "Which quality levels are acceptable to end users and which ones not?". In this paper we investigate the application of acceptability to the domain of QoE assessment for data services. To this end, we perform a critical review of the term's utilization and operationalization in related fields and discuss the results of a series of mobile broadband QoE studies we performed in lab and field settings. Our results demonstrate that acceptability is a relevant and useful concept that also features a consistent mapping between subjects' binary acceptance and ordinal satisfaction ratings, even across application scenarios as different as web browsing and file downloads. However, it is also a highly context-dependent concept since users' rating behaviors and thresholds diverge between lab and field settings. Acceptability thus needs to be evaluated in situ in the field in order to guarantee generalizable, ecologically valid results.
TL;DR: In this paper, the authors examine the arguments most commonly made in favor of FTTH, examining their logic and underlying evidence, and find that these arguments often inappropriately use benefits of basic broadband to make the case for the upgrade to superfast broadband, or use the benefits of providing superfast to business premises to argue for providing super fast to homes.
Abstract: Purpose – Governments around the world are providing multi‐billion dollar subsidies to roll out fiber to the home (FTTH) to enable superfast broadband (50 Mbps and above). The premise for this is a belief that superfast broadband brings substantial economic and societal benefits. This paper's purpose is to examine whether this belief is well founded.Design/methodology/approach – The authors critically review the arguments most commonly made in favor of FTTH, examining their logic and underlying evidence.Findings – The paper finds that these arguments often inappropriately use benefits of basic broadband to make the case for the upgrade to superfast broadband, or use the benefits of providing superfast to business premises to argue for providing superfast to homes. The authors find the evidence that basic broadband brings economic growth is patchy, and that frequently studies that argue for a link do not adequately distinguish between correlation and causation.Originality/value – Thus the authors conclude ...
TL;DR: This paper proposes an adaptive scheme that maintains the highest bandwidth efficiency obtainable by both opportunistic and full network coding schemes in wireless MBS, and derives performance metrics for opportunistic network coding using random graph theory.
Abstract: Network coding has recently attracted attention as a substantial improvement to packet retransmission schemes in wireless multicast broadcast services (MBS). Since the problem of finding the optimal network code maximizing the bandwidth efficiency is hard to solve and hard to approximate, two main network coding heuristic schemes, namely opportunistic and full network coding, were suggested in the literature to improve the MBS bandwidth efficiency. However, each of these two schemes usually outperforms the other in different receiver, demand, and feedback settings. The continuous and rapid change of these settings in wireless networks limits the bandwidth efficiency gains if only one scheme is always employed. In this paper, we propose an adaptive scheme that maintains the highest bandwidth efficiency obtainable by both opportunistic and full network coding schemes in wireless MBS. The proposed scheme adaptively selects, between these two schemes, the one that is expected to achieve the better bandwidth efficiency performance. The core contribution in this adaptive selection scheme lies in our derivation of performance metrics for opportunistic network coding, using random graph theory, which achieves efficient selection when compared to appropriate full network coding parameters. To compare between different complexity levels, we present three approaches to compute the performance metric for opportunistic coding using different levels of knowledge about the opportunistic coding graph. For the three considered approaches, simulation results show that our proposed scheme almost achieves the bandwidth efficiency performance that could be obtained by the optimal selection between the opportunistic and full coding schemes.
TL;DR: In this paper, radio relays are one of the possible contenders to extend the capacity and reliability of broadband data channels envisaged for 4G and above, and several research and standardization groups are engaged in evaluating and evolving the range of applications with relays.
Abstract: Wireless radio relays are one of the possible contenders to extend the capacity and reliability of broadband data channels envisaged for 4G and above. Several research and standardization groups are engaged in evaluating and evolving the range of applications with radio relays. There are both pros and cons of this technology, which needs to be carefully addressed before its actual implementation. Its cost effectiveness will also be a decid ing factor in a particular application sce nario with respect to other competing technologies.
TL;DR: In this paper, the authors presented and analyzed three basic dynamic wavelength allocation scenarios for a hybrid wavelength division multiplexing-time division multiple access (WDM-TDMA) PON.
Abstract: Optical access systems are now considered a feasible alternative to the predominant broadband access technologies, while, at the same time, passive optical networks (PONs) are viewed as an attractive and promising type of fiber access system. In this paper we present and analyze three basic dynamic wavelength allocation scenarios for a hybrid wavelength division multiplexing-time division multiple access (WDM-TDMA) PON. We propose new teletraffic loss models for calculating call-level performance measures, like connection failure probabilities (due to unavailability of a wavelength) and call blocking probabilities (due to the restricted bandwidth capacity of a wavelength). The PON accommodates bursty service-classes of ON-OFF traffic. The proposed models are extracted from one-dimensional Markov chains, which describe the wavelength occupancy in the PON, and two-dimensional Markov chains, which describe the bandwidth occupancy inside a wavelength. The accuracy of the proposed models is validated through simulation and is found to be quite satisfactory. Moreover, these models are computationally efficient because they are based on recursive formulas.
01 Dec 2011
TL;DR: The design of a high-capacity multi-beam system has been carried out, to assess the potential applicability of a hybrid space-ground processing architecture (Digisat) for satellite broadband systems; this is achieved via hybridspace-ground beamforming, MIMO and MIMo-MUD, Precoding, as well as Digital Feeder link techniques.
Abstract: Signal processing in satellite applications is usually performed either on-ground or on-board, i.e. at the gateway station or in the payload. Within the framework of the European Space Agency (ESA) SatNEx III study, a hybrid approach has been considered by splitting the processing between the satellite and the gateway, aiming to strike a better balance between performance and payload complexity. The design of a high-capacity multi-beam system has been carried out, to assess the potential applicability of a hybrid space-ground processing architecture (Digisat) for satellite broadband systems; this is achieved via hybrid space-ground beamforming, MIMO and MIMO-MUD, Precoding, as well as Digital Feeder link techniques.
TL;DR: Critical Discourse Analysis confirms that the growing use of digital inclusion rhetoric around broadband deployments has brought the social inclusion issue to the forefront, and effectively links discourse and technology with discursive practices and types.
TL;DR: In this article, the authors argue that broadband development policy in Canada must be re-framed to address the specific needs of First Nations and argue that First Nations broadband projects offer on-the-ground examples of a First Mile approach.
Abstract: Across Canada, rural and remote First Nations face a significant 'digital divide'. As self-determining autonomous nations in Canada, these communities are building broadband systems to deliver public services to their members and residents. To address this challenge, First Nations are working towards a variety of innovative, locally driven broadband development initiatives. This paper contributes a theoretical discussion that frames our understanding of these initiatives by drawing on the paradigm of the 'First Mile' (Paisley & Richardson, 1998). We argue that broadband development policy in Canada must be re-framed to address the specific needs of First Nations. The First Mile position foregrounds community-based involvement, control, and ownership: a consideration we suggest has particular resonance for First Nations. This is because it holds potential to move beyond the historical context of paternalistic, colonial-derived development policies, in the context of broadband systems development. We argue First Nations broadband projects offer on-the-ground examples of a First Mile approach, and call for more research in this area.