Showing papers in "IEEE Communications Magazine in 2006"
TL;DR: The sensor network properties that are crucial for the design of MAC layer protocols are outlined and several MAC protocols proposed for sensor networks are described, emphasizing their strengths and weaknesses.
Abstract: Wireless sensor networks are appealing to researchers due to their wide range of application potential in areas such as target detection and tracking, environmental monitoring, industrial process monitoring, and tactical systems. However, low sensing ranges result in dense networks and thus it becomes necessary to achieve an efficient medium-access protocol subject to power constraints. Various medium-access control (MAC) protocols with different objectives have been proposed for wireless sensor networks. In this article, we first outline the sensor network properties that are crucial for the design of MAC layer protocols. Then, we describe several MAC protocols proposed for sensor networks, emphasizing their strengths and weaknesses. Finally, we point out open research issues with regard to MAC layer design.
1,283 citations
TL;DR: The most interesting case studies related to opportunistic networking are surveyed and a taxonomy for the main routing and forwarding approaches in this challenging environment is discussed and organized.
Abstract: Opportunistic networks are one of the most interesting evolutions of MANETs. In opportunistic networks, mobile nodes are enabled to communicate with each other even if a route connecting them never exists. Furthermore, nodes are not supposed to possess or acquire any knowledge about the network topology, which (instead) is necessary in traditional MANET routing protocols. Routes are built dynamically, while messages are en route between the sender and the destination(s), and any possible node can opportunistically be used as next hop, provided it is likely to bring the message closer to the final destination. These requirements make opportunistic networks a challenging and promising research field. In this article we survey the most interesting case studies related to opportunistic networking and discuss and organize a taxonomy for the main routing and forwarding approaches in this challenging environment. We finally envision further possible scenarios to make opportunistic networks part of the next-generation Internet
1,201 citations
TL;DR: An overview of highway cooperative collision avoidance (CCA), which is an emerging vehicular safety application using the IEEE- and ASTM-adopted Dedicated Short Range Communication (DSRC) standard, and an example of the safety performance of CCA using simulated vehicle crash experiments.
Abstract: This article presents an overview of highway cooperative collision avoidance (CCA), which is an emerging vehicular safety application using the IEEE- and ASTM-adopted Dedicated Short Range Communication (DSRC) standard. Along with a description of the DSRC architecture, we introduce the concept of CCA and its implementation requirements in the context of a vehicle-to-vehicle wireless network, primarily at the Medium Access Control (MAC) and the routing layer. An overview is then provided to establish that the MAC and routing protocols from traditional Mobile Ad Hoc networks arc not directly applicable for CCA and similar safety-critical applications. Specific constraints and future research directions are then identified for packet routing protocols used to support such applications in the DSRC environment. In order to further explain the interactions between CCA and its underlying networking protocols, we present an example of the safety performance of CCA using simulated vehicle crash experiments. The results from these experiments arc also used to demonstrate the need for network data prioritization for safety-critical applications such as CCA. Finally, the performance sensitivity of CCA to unreliable wireless channels is discussed based on the experimental results.
920 citations
TL;DR: The use of this conduit in the security mechanism of BASN is explored by a biometrics approach that uses an intrinsic characteristic of the human body as the authentication identity or the means of securing the distribution of a cipher key to secure inter-BASN communications.
Abstract: The development of the wireless body area sensor network (BASN) is imperative for modern telemedicine and m-health, but security remains a formidable challenge yet to be resolved. As nodes of BASN are expected to be interconnected on or in the human body, the body itself can form an inherently secure communication pathway that is unavailable to all other kinds of wireless networks. This article explores the use of this conduit in the security mechanism of BASN; that is, by a biometrics approach that uses an intrinsic characteristic of the human body as the authentication identity or the means of securing the distribution of a cipher key to secure inter-BASN communications. The method was tested on 99 subjects with 838 segments of simultaneous recordings of electrocardiogram and photoplethysmogram. By using the interpulse interval (IPI) as the biometric trait, the system achieved a minimum half total error rate of 2.58 percent when the IPIs measured from signals, which were sampled at 1000 Hz, were coded into 128-bit binary sequences. The study opens up a few key issues for future investigation, including compensation schemes for the asynchrony of different channels, coding schemes, and other suitable biometric traits.
581 citations
TL;DR: Promising technologies to fulfil 3G evolution targets are presented, including OFDM, multi-antenna solutions, evolved QoS and link layer concepts, and an evolved architecture, indicating that the requirements can indeed be reached using the proposed technologies.
Abstract: Work has started in the 3GPP to define a long-term evolution for 3G, sometimes referred to as super-3G, which will stretch the performance of 3G technology, thereby meeting user expectations in a 10-year perspective and beyond. The fundamental targets of this evolution - to further reduce user and operator costs and to improve service provisioning - will be met through improved coverage and system capacity as well as increased data rates and reduced latency. This article presents promising technologies to fulfil these targets, including OFDM, multi-antenna solutions, evolved QoS and link layer concepts, and an evolved architecture. Furthermore, the results of a performance evaluation are presented, indicating that the requirements can indeed be reached using the proposed technologies.
567 citations
529 citations
TL;DR: By defining cognitive networks, examining their relationship to other technologies, discussing critical design issues, and providing a framework for implementation, this article aims to establish a foundation for further research and discussion.
Abstract: In this article we advance the idea of a cognitive network, capable of perceiving current network conditions and then planning, learning, and acting according to end-to-end goals. Cognitive networks are motivated by the complexity, heterogeneity, and reliability requirements of tomorrow's networks, which are increasingly expected to self-organize to meet user and application objectives. We compare and contrast cognitive networks with related research on cognitive radios and cross-layer design. By defining cognitive networks, examining their relationship to other technologies, discussing critical design issues, and providing a framework for implementation, we aim to establish a foundation for further research and discussion
496 citations
TL;DR: Recent advances in energy-aware platforms for information processing and communication protocols for sensor collaboration are described and emerging, hitherto largely unexplored techniques, such as the use of environmental energy harvesting and the optimization of the energy consumed during sensing are looked at.
Abstract: In recent years, sensor networks have transitioned from being objects of academic research interest to a technology that is frequently being deployed in real-life applications and rapidly being commercialized. However, energy consumption continues to remain a barrier challenge in many sensor network applications that require long lifetimes. Battery-operated sensor nodes have limited energy storage capability due to small form-factors, or operate in environments that rule out frequent energy replenishment, resulting in a mismatch between the available energy budget for system operation and the required energy budget to obtain desired lifetimes. This article surveys several techniques that show promise in addressing and alleviating this energy consumption challenge. In addition to describing recent advances in energy-aware platforms for information processing and communication protocols for sensor collaboration, the article also looks at emerging, hitherto largely unexplored techniques, such as the use of environmental energy harvesting and the optimization of the energy consumed during sensing.
473 citations
TL;DR: The technology behind the new H.264/MPEG4-AVC standard is discussed, focusing on the main distinct features of its core coding technology and its first set of extensions, known as the fidelity range extensions (FRExt).
Abstract: H.264/MPEG4-AVC is the latest video coding standard of the ITU-T video coding experts group (VCEG) and the ISO/IEC moving picture experts group (MPEG). H.264/MPEG4-AVC has recently become the most widely accepted video coding standard since the deployment of MPEG2 at the dawn of digital television, and it may soon overtake MPEG2 in common use. It covers all common video applications ranging from mobile services and videoconferencing to IPTV, HDTV, and HD video storage. This article discusses the technology behind the new H.264/MPEG4-AVC standard, focusing on the main distinct features of its core coding technology and its first set of extensions, known as the fidelity range extensions (FRExt). In addition, this article also discusses the current status of adoption and deployment of the new standard in various application areas
471 citations
TL;DR: Different and novel aspects of handoff are presented and handoff related issues of fourth generation systems are discussed and desirable handoff features are presented.
Abstract: As mobile wireless networks increase in popularity and pervasiveness, we are faced with the challenge of combining a diverse number of wireless networks. The fourth generation of wireless communications is expected to integrate a potentially large number of heterogeneous wireless technologies in what could be considered a huge step forward toward universal seamless access. One of the main challenges for seamless mobility is the availability of reliable horizontal (intrasystem) and vertical (intersystem) handoff schemes. Efficient handoff schemes enhance quality of service and provide flawless mobility. This article presents different and novel aspects of handoff and discusses handoff related issues of fourth generation systems. Desirable handoff features are presented. Handoff decisions, radio link transfer, and channel assignment are described as stages of the complete handoff process. A vertical handoff decision function, which enables devices to assign weights to different network parameters, is also presented
377 citations
TL;DR: In this article existing proposals that use mobility in WSNs are summarized and a new approach to compute mobile platform trajectories is introduced.
Abstract: Wireless sensor networks are proposed to deliver in situ observations at low cost over long periods of time. Among numerous challenges faced while designing WSNs and protocols, maintaining connectivity and maximizing the network lifetime stand out as critical considerations. Mobile platforms equipped with communication devices can be leveraged to overcome these two problems. In this article existing proposals that use mobility in WSNs are summarized. Furthermore, a new approach to compute mobile platform trajectories is introduced. These solutions are also compared considering various metrics and design goals.
TL;DR: This article proposes a cross-layer optimization strategy that jointly optimizes the application layer, data link layer, and physical layer of the protocol stack using an application-oriented objective function in order to maximize user satisfaction.
Abstract: Mobile multimedia applications require networks that optimally allocate resources and adapt to dynamically changing environments. Cross-layer design (CLD) is a new paradigm that addresses this challenge by optimizing communication network architectures across traditional layer boundaries. In this article we discuss the relevant technical challenges of CLD and focus on application-driven CLD for video streaming over wireless networks. We propose a cross-layer optimization strategy that jointly optimizes the application layer, data link layer, and physical layer of the protocol stack using an application-oriented objective function in order to maximize user satisfaction. In our experiments we demonstrate the performance gain achievable with this approach. We also explore the trade-off between performance gain and additional computation and communication cost introduced by cross-layer optimization. Finally, we outline future research challenges in CLD.
TL;DR: A robust cross-layer architecture that leverages the inherent H.264 error resilience tools and the existing QoS-based IEEE 802.11e MAC protocol possibilities is proposed, which allows graceful video degradation while minimizing the mean packet loss and end-to-end delays.
Abstract: The recently developed H.264 video standard achieves efficient encoding over a bandwidth ranging from a few kilobits per second to several megabits per second. Hence, transporting H.264 video is expected to be an important component of many wireless multimedia services, such as video conferencing, real-time network gaming, and TV broadcasting. However, due to wireless channel characteristics and lack of QoS support, the basic 802.11-based channel access procedure is merely sufficient to deliver non-real-time traffic. The delivery should be augmented by appropriate mechanisms to better consider different QoS requirements and ultimately adjust the medium access parameters to the video data content characteristics. In this article we address H.264 wireless video transmission over IEEE 802.11 WLAN by proposing a robust cross-layer architecture that leverages the inherent H.264 error resilience tools (i.e., data partitioning); and the existing QoS-based IEEE 802.11e MAC protocol possibilities. The performances of the proposed architecture are extensively investigated by simulations. Results obtained indicate that compared to 802.11 and 802.11e, our cross-layer architecture allows graceful video degradation while minimizing the mean packet loss and end-to-end delays.
TL;DR: The topic of this article is to survey some lines of research that may be useful in developing a theory of in-network computation, which aims to elucidate how a wireless sensor network should efficiently perform such distributed computation.
Abstract: Sensor networks are not just data networks with sensors being the sources of data. Rather, they are often developed and deployed for a specific application, and the entire network operation is accordingly geared toward satisfying this application. For overall system efficiency, it may be necessary for nodes to perform computations on data, as opposed to simply originating or forwarding data. Thus, the entire network can be viewed as performing an application-specific distributed computation. The topic of this article is to survey some lines of research that may be useful in developing a theory of in-network computation, which aims to elucidate how a wireless sensor network should efficiently perform such distributed computation. We review several existing approaches to computation problems in network settings, with a particular emphasis on the communication aspect of computation. We begin by studying the basic two-party communication complexity model and how to optimally compute functions of distributed inputs in this setting. We proceed to larger multihop networks, and study how block computation and function structure can be exploited to provide greater computational throughput. We then consider distributed computation problems in networks subject to noise. Finally, we review some randomized gossip-based approaches to computing aggregate functions in networks. These are diverse approaches spanning many different research communities, but together may find a role in the development of a more substantial theoretical foundation for sensor networks.
TL;DR: The current proposals for cognitive radio deployment are surveyed, a new, potentially more spectrally efficient model for a wireless channel employing cognitive radios is presented, and fundamental limits on the communication possible over such a channel are obtained.
Abstract: In this article we review FCC secondary markets initiatives and how smart wireless devices could be used to increase spectral efficiency. We survey the current proposals for cognitive radio deployment, and present a new, potentially more spectrally efficient model for a wireless channel employing cognitive radios; the cognitive radio channel. This channel models the simplest scenario in which a cognitive radio could be used and consists of a 2 Tx, 2 Rx wireless channel in which one transmitter knows the message of the other. We obtain fundamental limits on the communication possible over such a channel, and discuss future engineering and regulatory issues
TL;DR: This article presents a classification of key management schemes in sensor networks delineating their similarities and differences, and describes a novel dynamic key management scheme, localized combinatorial keying (LOCK), and compares its security and performance with a representative staticKey management scheme.
Abstract: Numerous key management schemes have been proposed for sensor networks. The objective of key management is to dynamically establish and maintain secure channels among communicating nodes. Desired features of key management in sensor networks include energy awareness, localized impact of attacks, and scaling to a large number of nodes. A primary challenge is managing the trade-off between providing acceptable levels of security and conserving scarce resources, in particular energy, needed for network operations. Many schemes, referred to as static schemes, have adopted the principle of key predistribution with the underlying assumption of a relatively static short-lived network (node replenishments are rare, and keys outlive the network). An emerging class of schemes, dynamic key management schemes, assumes long-lived networks with more frequent addition of new nodes, thus requiring network rekeying for sustained security and survivability. In this article we present a classification of key management schemes in sensor networks delineating their similarities and differences. We also describe a novel dynamic key management scheme, localized combinatorial keying (LOCK), and compare its security and performance with a representative static key management scheme. Finally, we outline future research directions.
TL;DR: This article addresses the requirements of WDM upgraded EPONs and makes recommendations on an evolutionary WDM upgrade at the architecture, protocol, and dynamic bandwidth allocation algorithm levels, taking backward compatibility with MPCP and future-proofness against arbitrary WDM ONU structures into account.
Abstract: WDM EPONs not only allow for cautious pay-as-you-grow upgrades of single-channel TDM EPONs but also avoid linearly increasing polling cycle times for an increasing number of ONUS. In this article, we first provide a comprehensive overview of the state of the art of TDM EPONs and recently reported dynamic bandwidth allocation algorithms, including decentralized scheduling schemes. After reviewing previous work on WDM EPONs, we address the requirements of WDM upgraded EPONs and make recommendations on an evolutionary WDM upgrade at the architecture, protocol, and dynamic bandwidth allocation algorithm levels, taking backward compatibility with MPCP and future-proofness against arbitrary WDM ONU structures into account. We describe and compare online and offline scheduling paradigms for WDM EPONs. Our simulation results indicate that online scheduling can achieve lower delays, especially at high loads. We outline areas of future research on WDM EPONs.
TL;DR: A comprehensive classification of security policy conflicts that might potentially exist in a single security device or between different network devices in enterprise networks is presented and the high probability of creating such conflicts even by expert system administrators and network practitioners is shown.
Abstract: Network security polices are essential elements in Internet security devices that provide traffic filtering, integrity, confidentiality, and authentication. Network security perimeter devices such as firewalls, IPSec, and IDS/IPS devices operate based on locally configured policies. However, configuring network security policies remains a complex and error-prone task due to rule dependency semantics and the interaction between policies in the network. This complexity is likely to increase as the network size increases. A successful deployment of a network security system requires global analysis of policy configurations of all network security devices in order to avoid policy conflicts and inconsistency. Policy conflicts may cause serious security breaches and network vulnerability such as blocking legitimate traffic, permitting unwanted traffic, and insecure data transmission. This article presents a comprehensive classification of security policy conflicts that might potentially exist in a single security device (intrapolicy conflicts) or between different network devices (interpolicy conflicts) in enterprise networks. We also show the high probability of creating such conflicts even by expert system administrators and network practitioners.
TL;DR: There is a continuing need for increased capacity for military applications, especially in network-centric operational concepts that promote the use of information as fundamental for gaining superiority on the battlefield, and free-space optical communications has the potential to meet these emerging military needs by offering dramatic increases in capacity.
Abstract: There is a continuing need for increased capacity for military applications, especially in network-centric operational concepts that promote the use of information as fundamental for gaining superiority on the battlefield. As an example, the access to, and distribution of, sensor data is a major tenet of network-centric warfare and yet radio frequency (RF) links will struggle to provide the needed capacity. Free-space optical communications (FSOC) has the potential to meet these emerging military needs by offering dramatic increases in capacity. However, there are many technical challenges al multiple layers of the communications protocol stack. This article describes these challenges and discusses some mitigation approaches to provide a path to realizing this capability on the battlefield
TL;DR: The third-generation WCDMA standard has been enhanced to offer significantly increased performance for packet data and broadcast services through the introduction of high-speed downlink packet access, enhanced uplink, and multimedia broadcast multicast services.
Abstract: The third-generation WCDMA standard has been enhanced to offer significantly increased performance for packet data and broadcast services through the introduction of high-speed downlink packet access (HSDPA), enhanced uplink, and multimedia broadcast multicast services (MBMS). This article provides an overview of the key technologies used, the reasons behind their selection, and their integration into WCDMA. Performance results are also included to exemplify the performance possible in an evolved WCDMA network.
TL;DR: The DRAGON project is developing technology and deploying network infrastructure which allows dynamic provisioning of network resources in order to establish deterministic paths in direct response to end-user requests.
Abstract: Dynamic resource allocation in GMPLS optical networks (DRAGON) defines a research and experimental framework for high-performance networks required by grid computing and e-science applications. The DRAGON project is developing technology and deploying network infrastructure which allows dynamic provisioning of network resources in order to establish deterministic paths in direct response to end-user requests. This includes multidomain provisioning of traffic-engineering paths using a distributed control plane across heterogeneous network technologies while including mechanisms for authentication, authorization, accounting (AAA), and scheduling. A reference implementation of this framework has been instantiated in the Washington, DC area and is being utilized to conduct research and development into the deployment of optical networks technologies toward the satisfaction of very-high-performance science application requirements.
TL;DR: Two RFID applications in telemedicine are proposed: studying supply and demand of doctors, nurses, and patients in hospitals and healthcare, and developing mobile telemedicsine services.
Abstract: Radio frequency identification systems have many applications in manufacturing, supply chain management, inventory control, and telemedicine. In an RFID system, products and objects are given RFID tags to identify themselves. However, security and privacy issues pose significant challenges on these systems. In this article we first briefly introduce RFID systems. Then two RFID applications in telemedicine are proposed: studying supply and demand of doctors, nurses, and patients in hospitals and healthcare, and developing mobile telemedicine services. The security and privacy issues of RFID, and their solutions are discussed as well.
TL;DR: An overview of the military MANET problem space is provided, describing the ideal military MANet solution, and several deficiencies are highlighted that exist between MANET technologies and the desired capability.
Abstract: Mobile ad hoc networks (MANETs) are considered by many as fundamental to realizing the global information grid (GIG) and the vision of network-centric warfare. Indeed, a fully realized MANET would be powerful in enabling highly mobile, highly responsive, and quickly deployable tactical forces. However, significant technical challenges remain before this realization is viable. Addressing these deficiencies is a significant task that will require the invention and adoption of new technology. The goal of this article is not to declare these capabilities impossible to achieve. Rather, it is to manage the expectation of the capabilities achievable in the foreseeable future through edification on the technical difficulties standing between current technology and the desired capabilities. This article provides an overview of the military MANET problem space, describing the ideal military MANET solution. Several deficiencies are highlighted that exist between MANET technologies and the desired capability. Identified technical issues include system-level architecture, routing (both interior and exterior), management, security, and medium access control (MAC), with an emphasis on the former two areas
TL;DR: A number of advantages and flexibilities an TDD system can bring to 4G systems that an FDD system cannot offer are presented, and the major challenges, including cross-slot interference, in applying TDD in practice are identified.
Abstract: Frequency-division duplexing and time-division duplexing are two common duplexing methods used in various wireless systems. However, there are advantages and technical issues associated with them. In this article we discuss in detail the features, and the design and implementation challenges of FDD and TDD systems for 4G wireless systems. In particular, we present a number of advantages and flexibilities an TDD system can bring to 4G systems that an FDD system cannot offer, and identify the major challenges, including cross-slot interference, in applying TDD in practice. Due to the fact that cross-slot interference is one of the critical challenges to employing TDD in cellular networks, we also provide a quantitative analysis on its impact on co-channel and adjacent channel interfering cells
TL;DR: The numerical and simulation results obtained demonstrate that the proposed cross-layer model can efficiently characterize the interaction between the physical layer infrastructure and upper layer protocols' QoS provisioning performance.
Abstract: In this article we propose a cross-layer approach to investigate the impact of the physical-layer infrastructure on the data-link-layer QoS performance in mobile wireless networks. At the physical layer, we take the MIMO diversity schemes as well its AMC into account. At the data-link layer, our focus is on how this physical-layer infrastructure influences the real-time multimedia QoS provisioning performance such as delay-bound violation and buffer-overflow probabilities. To achieve this goal, we first model the physical-layer service process as a finite state Markov chain. Based on this FSMC model, we then characterize the QoS performance at the data-link layer using the effective capacity approach, which turns out to be critically important for the statistical QoS guarantees in mobile wireless networks. The numerical and simulation results obtained demonstrate that the proposed cross-layer model can efficiently characterize the interaction between the physical layer infrastructure and upper layer protocols' QoS provisioning performance.
TL;DR: IMS is examined from a mobile operator's perspective and its possible adaptation to the next-generation networks is analysed.
Abstract: As third-generation (mobile) networks (3G networks) become a commercial reality, strong movements are emerging in the direction of a common infrastructure based on the Internet protocol (IP) The users' mobile devices are like another IP host connected to the Internet In such a scenario, the network operator infrastructure is degraded to bit pipes To avoid this, the 3G partnership project (3GPP) and ETSI TISPAN have designed IP multimedia subsystem (IMS), a service platform that aims to place the network operator again in the central role of service provisioning In this article we examine IMS from a mobile operator's perspective and analyse its possible adaptation to the next-generation networks
TL;DR: In this article, the authors describe a fully integrated 90 nm CMOS software-defined radio receiver operating in the 800 MHz to 5 GHz band, which acts as a signal conditioner for the analog-to-digital converters, emphasizing only the wanted channel.
Abstract: This article describes a fully integrated 90 nm CMOS software-defined radio receiver operating in the 800 MHz to 5 GHz band. Unlike the classical SDR paradigm, which digitizes the whole spectrum uniformly, this receiver acts as a signal conditioner for the analog-to-digital converters, emphasizing only the wanted channel. Thus, the ADCs operate with modest resolution and sample rate, consuming low power. This approach makes portable SDR a reality
TL;DR: Two distributed approaches that integrate information about most relevant physical impairments in RWA and lightpath provisioning are presented and assessed and functional requirements, architectural functional blocks, and protocol extensions for implementing either an impairment-aware real-time RWA, or a light Path provisioning based on impairment- aware signaling are provided.
Abstract: The absence of electrical regenerators in transparent WDM networks significantly contributes to reduce the overall network cost. In transparent WDM networks, a proper resource allocation requires that the presence of physical impairments in routing and wavelength assignment (RWA) and lightpath provisioning be taken into account. In this article a centralized, a hybrid centralized-distributed and two distributed approaches that integrate information about most relevant physical impairments in RWA and lightpath provisioning are presented and assessed. Both centralized and hybrid approaches perform a centralized path computation at the management-plane level, utilizing physical impairment information, while the lightpath provisioning is done by the management plane or the control plane, respectively. The distributed approaches fall entirely within the scope of the ASON/GMPLS control plane. For these two approaches, we provide functional requirements, architectural functional blocks, and protocol extensions for implementing either an impairment-aware real-time RWA, or a lightpath provisioning based on impairment-aware signaling.
TL;DR: In this article, the authors survey the benefits and challenges posed by the deployment and operation of wireless communications in support of healthcare networks and explore some of these issues, including deployment, interference, and mobility, and provide insights for potential solutions.
Abstract: The objectives of this article are to survey the benefits and challenges posed by the deployment and operation of wireless communications in support of healthcare networks. While the main advantage of wireless communications remains to provide ubiquitous connectivity, thus allowing greater physical mobility and interoperability, a number of engineering issues need to be addressed before this vision is realized. Our intent in this article is to explore some of these issues, including deployment, interference, and mobility, and provide insights for potential solutions.
TL;DR: The technical trends are WDM, 10 Gb/s, and longer reach/higher splits, and the evolution from installed legacy in possible future optical access standards is taken account.
Abstract: Optical access technology is now standardized, commercially available, and being deployed in some countries. In general, technology continues to develop, and optical access is no exception. New optical access technologies are now being widely reported; the technical trends are WDM, 10 Gb/s, and longer reach/higher splits. It is also important to take account of the evolution from installed legacy in possible future optical access standards