Broadband Access

Passive optical network (PON) is one of the most successful broadband access architectures being deployed worldwide. PONs provide high capacity, increased reach, and low-power consumption at a very reasonable cost, on par with the cost of DSL deployments today. This paper provides an overview of present and emerging PON technologies, and discusses PON's important role in the evolution of optical access from the architectural perspective. While describing the evolution of optical access architecture, we present two important integration options: optical+wireless access integration and metro+access integration. Potential PON capacity upgrades are discussed with special emphasis on achieving a seamless upgrade. We evaluate different PON evolution strategies in the context of next-generation PON, where gradual, demand-based migration demonstrates a number of significant benefits.

AUTHORS Stefano Migliorisi (Tech4Dev) Alessandra Balletti (Wi‐ART) Karl Edwards (Excelsio Communications) Roberto Donà (NPV) David Mendoza Ugo Silva Dias Miguel Collado di Franco Luis Deza ... EDITOR Jaime García Alba (Multilateral Investment Fund)

Abstract—A hybrid fiber–radio access network architecture for simultaneous wireline and wireless transmissions of Data-Over-Cable Service Interface Specification (DOCSIS) signals is pre-sented. An all-optical harmonic up-conversion technique using a dual-drive ...

Education is seen as a route to full participation in society, and widening participation in education and lifelong learning as a way of including those who are currently excluded from many of the benefits of society. The use of learning technology is perceived as a means of widening participation in higher education by enabling participation by non-traditional students. E-learning is perceived as lowering barriers of time and space to enable non-traditional students to attend campus-based education while accessing resources at a time and place of their choosing. This research finds a digital divide with some students financially unable to afford technology and broadband access, others without the skills to engage with learning technology, and some culturally less able to benefit from technological enrichment. It also finds gender and generational differences disenfranchising some students.

This article has the objective of obtaining detailed knowledge on the regulation of access to next generation networks (NGNs) and its effects on a specific country, specif- ically Spain, given that it can be used as a reference to gain a better perspective and draw several conclusions on what has been a global pursuit during a key period of time, 2007–2015, for the electronic communications market in the European Union, where the current and historical role and position of incumbent operators is critical. Focused on NGNs based on fibre to the home solutions and the collateral aspects that support their deployment (coexistence with older access networks based on copper pairs and maintained regu- lation regarding wholesale broadband transmission services), this paper takes up new issues: the opening of transmission infrastructure and installation and the regulation of new net- work infrastructures in buildings. In doing so, we obtain a model of infrastructure and service competition that is also regulated by price, which promotes the deployment of new networks. We have generically evaluated the effect of this model on the deployment of NGNs in Spain and its effects on coverage, access to broadband service and the market shares of the different operators. The conclusions describe a successful model to a large degree because except when addressing the strictly economic aspect of return on investment, the objectives proposed by the regulatory agency have been achieved to date (2015) and within a long-term horizon (2008–2023). Given that this phenomenon is not an exact sci- ence, the conclusions regarding the goodness of the model will always be subjective and nuanced; however, we indicate that it will be necessary to strengthen the path followed by the regulatory agency through the monitoring of resolutions that maintain a strong framework and sufficient security for operators and users. Certain issues that were not addressed should be studied, given that they have proven to be critical: geographical discrimination, fibre loop disaggregation, new prices for wholesale services that adapt reference offers and greater control of the replicability of retail services. We are facing an open model with a future, as the new measures (2015) of the Spanish regulatory agency show in terms of the near future.

While bandwidth for Internet access in urban areas is steadily increasing in recent years, some rural areas are still suffering from digital divide. This paper presents a broadband Internet access solution developed by the ADHOCSYS project, which is financed by the European Commission under the FP6 IST strategic objective "Broadband for All". Aiming at providing reliable Internet access in rural and mountainous regions where xDSL is not available or non-profitable, the ADHOCSYS network provides a cost-effective solution based on multi-hop wireless networks. Starting from a general description of the network architecture and application scenarios, the paper presents various challenges and technical solutions which have been investigated within the project, including routing, QoS, power supply, and security. A real-life pilot ADHOCSYS network has been deployed in Northern Italy to validate the broadband access solution developed by the project.

We analyse the impact of regulation, industrial policy and jurisdictional allocation on broadband deployment using a theoretical model and an empirical estimation. Although central powers may be more focused and internalize interjurisdictional externalities, decentralized powers may internalize local horizontal policy spillovers and use a diversity of objectives as a commitment device in the presence of sunk investments. The latter may, for instance, alleviate the collective action problem of the joint use of rights of way and other physical infrastructures. In the empirical exercise, using data for OECD and EU countries for the period 1999-2006, we examine whether centralization promotes new telecommunications markets, in particular the broadband access market. The existing literature, in the main, claims it does, but we find no support for this claim in our data. Our results show that indicators of national industrial policy are a weakly positive determinant of broadband deployment and that different measures of centralization are either irrelevant or have a negative impact on broadband penetration. JEL Codes: L50, L96, K23, H77

The wavelength-division-multiplexed passive optical network (WDM-PON) is considered to be the next evolutionary solution for a simplified and future-proofed access system that can accommodate exponential traffic growth and bandwidth-hungry new applications.

Satellites are well suited for broadband communications. In this paper we consider the special features of satellite systems, some of the broadband applications that are well-suited for satellites and some of the technologies which make possible broadband satellite communications, as well as the research programs that led to their development. We describe how such technologies, and other factors, have contributed to the evolution of broadband satellite systems, and discuss some of the challenges in establishing such systems. We finish by offering some concluding remarks on the role of satellites for broadband access.

Mobile telephony allowed us to talk on the move. The internet turned raw data into helpful services that people found easy to use. These two technologies are converging to create a third generation mobile services. 3G technologies were rolled out to provide an increase in capacity over Second Generation (2G) mobile networks, both for data and voice services. WiMAX is a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL. Mobile WiMAX technology enables the mobility features and attributes for the end user. This paper discusses the 3G and WiMAX technologies within the perspective of Mobile Technology.

Many advanced data services are driving up wireless technology, which is further boosted by growth in advanced market segments. The wireless industry is evolving from a Web of independent networks into a single integrated network with multiple standards; the expectation is that WI-FI, WI-MAX and 3G will coexist to enable a host of exerting new applications and business models. This paper focuses on concepts of WI-MAX technology, which employs microwave for the transfer of data wirelessly, and it also presents its comparison with WI-FI, and 3G technologies. WI-MAX is delivering broadband wireless access to the masses and represents alternative to digital subscriber lines (DSL) and cable broadband access. WI-MAX is based on IEEE 802.16 standard and is scalable. It stands for wireless (WI) microwave access (MAX). WI-MAX will provide anywhere, anytime connectivity. Features of WI-MAX are OFDM i.e. orthogonal frequency division multiplexing, sub channelization, directional antennas and adaptive modulation, which make WI-MAX as the technology of today. The Benefit of WI-MAX technology is that the signals can be run very close to each other on wireless channels. Super narrow lanes can put a lot of traffic over them without disturbance. Many technologies currently available can only provide line of sight (LOS) coverage; the technology behind WI-MAX has been optimized to provide excelled non-line of sight (NLOS) coverage.

Services for video content distribution over the Internet, live and on-demand, are increasing in popularity with the dissemination of broadband access networks. This work identifies two orthogonal approaches to the great challenge of delivering television content over IP networks in a scalable manner. Commercial initiatives towards supporting television content over IP networks are currently under deployment, motivated mainly by emerging convergent multimedia networks. Commercial IPTV is typically based on a private IP network and makes use of multicast transmission techniques with the goal of delivering a service with quality equivalent to conventional broadcast TV. However, the commercial IPTV has limited coverage, in conformity with the extent of its private IP network. On the other hand, other initiatives have been proposed aiming to deploy a service with global coverage and using the infrastructure of the Internet. The basic idea is to take advantage of the user's idle resources, in order to form a cooperative environment for TV distribution. The great challenge of the cooperative IPTV is to guarantee the quality of the service and to provide incentive mechanisms for cooperation. This work presents architectures for video distribution in large scale over the Internet. It will be discussed the state-of-art of current approaches and it will be presented new distribution proposals capable of providing sustainability for a TV over IP service on the Internet, including solutions based on application level multicast such as content distribution networks, multi-paths, pseudo-servers and peer-to-peer.

The access network infrastructure plays an important role in the overall performance of the network, next generation access networks (NGA) must be able to access diverse services, and should incorporate adequate architectures that include mechanisms for the integration of different technologies. New optical access technologies trends are: WDM, 10 Gb/s, and longer reach/higher splits. It is also important to take

Wireless broadband technologies provide ubiquitous broadband access to wireless users, enabling services that were available only to wireline users. In this paper, we summarize emerging wireless broadband access technologies, ranging from WLANs to satellite communications.,We explain the latest standards,in the IEEE 802.11 and IEEE 802.16 families in detail. The MAC layer mechanisms of IEEE 802.11e, 802.11n, and 802.11s standards

The access network infrastructure plays an important role in the overall performance of the network, next generation access networks (NGA) must be able to access diverse services, and should incorporate adequate architectures that include mechanisms for the integration of different technologies. New optical access technologies trends are: WDM, 10 Gb/s, and longer reach/higher splits. It is also important to take into account the evolution of the installed legacy PONs to the next generation optical access networks. The present paper goes through such topics, focusing on the research being carried out to develop dynamic bandwidth algorithms for the 10 Gb/s new EPON standard (IEEE 802.3av). We summarize results and point out issues that will require further investigation. Postprint (published version)

IEEE 802.16 technology has emerged as a competitive alternative to wireline broadband access solution. IEEE 802.16 can provide quality of service (QoS) guarantees for heterogeneous classes of traffic with different QoS requirements. The standard, however, leaves open the resource management and scheduling issues, which are crucial components to guarantee QoS performance. The main objective of this paper is to provide a better understanding of the missing components to ensure QoS support in IEEE 802.16 fixed broadband wireless networks (BWNs), namely scheduling and connection admission control (CAC) schemes. First, we highlight the key challenges in designing such schemes, for both point-to-multipoint (PMP) and mesh modes. Then, we survey, classify, and compare different scheduling and admission control mechanisms proposed in this work-in-progress area.

Passive Optical Networks are thought to be the next step in the development of Access Networks and providing broadband access in the "last mile" area. Ethernet PONs (EPON) gain the most attention from the industry as they offer highly flexible, cost effective solution. In this paper we propose algorithms that provide Dynamic Bandwidth Allocation and shift the burden of queue

In this paper, the main role of satellite systems in hybrid satellite/terrestrial networks will be highlighted, as well as the main functions which should be performed to optimize the performance of these hybrid networks. Then, some typical services believed to occupy a great portion of the future telecommunication service market and benefiting from these hybrid architectures will be presented. Generally speaking, the list of hybrid architectures presented in this paper is not exhaustive but reflects the main work carried out in the institute of communications and navigation of DLR and in the framework of the Satellite Communications Network of Excellence "SatNEx" subsidized by the European Union, more accurately in the focus topic "Hybrid broadband network architectures" of the Joint Activity 2130 "Broadband Access Network". The critical issues related to hybrid satellite/terrestrial architectures will be identified and analyzed all along this paper and illustrated by selected realistic examples.

Broadband satellite will play an important role to provide universal broadband access for the users. In order to lower the cost, the next-generation satellite systems should support IPv6 and seamlessly integrate with terrestrial networks, including wireless local loops. Based on the studies on the requirements and design constraints, in this paper, a novel network architecture has been proposed as a potential solution to the above problems. The proposed network architecture supports both transparent and regenerative topologies and can seamlessly interworking with WLL. It also integrates QoS, multicast, security, and mobility functions to support a range of transport requirements. How to apply this network architecture to support three different scenarios, namely corporate application scenario, residential application scenario and collective access terminal scenario, are also described.

Abstract--All communities whether they are rural or urban will have to respond to safety, disasters, and emergency situations. These situations place a special burden on communication systems for having a fully operational system. Given the shortcomings of current Public ...

In this paper, we present a low-power high-performance WiMAX chipset fully compliant with IEEE 802.16e specification corrigendum 1, 2 for mobile broadband access and WiMAX Forum system profile Wave2. The chipset is comprised of a 632.7-mW/24.99-mm modem/router chip and a 364-mW/11.05-mm dual-band 2 2 MIMO RF transceiver chip, both developed in 65-nm CMOS process. The proposed chipset is capable of handling a maximum peak WiMAX downlink (DL) throughput of 70 Mbps. Moreover, the chipset can reach up to 100.5-dBm sensitivity in a 10-MHz AWGN channel, which outperforms WiMAX Forum mobile radio conformance test (MRCT) by 9.5 dB. Such high sensitivity is due to the proposed low-noise high-linearity RF transceiver chip, which has 2.5-dB RX noise figure (NF) and 37-dB TX error vector magnitude (EVM), and the applied high-performance baseband signal processing algorithms. Several low-power design techniques-from SW level, firmware/DSP level, to HW module level-have been implemented to enable portable applications. The modem/router chip is highly integrated and has rich features and various interfaces for applications such as router or VoIP phone. Furthermore, this is the only published WiMAX chipset which has been in mass production.

Ethernet Passive Optical Networks (EPONs) have attracted considerable attention from industry as they offer a simple, highly flexible and cost effective solution to the problem of providing broadband access to a customer. In this paper, a new approach to bandwidth allocation in EPONs is presented where the Optical Line Terminator (OLT) has full control over the access mechanism. This results in much simpler Optical Network Unit (ONU) architecture. It is shown in this paper that such an OLT-centric architecture offers full support for Differentiated Services and makes enforcement of Service Level Agreements possible. Extensive simulation experiments show that bandwidth allocation algorithms deployed in such a centralized environment can deliver good performance in terms of average and maximum packet delay. In this paper two new algorithms are introduced that target SLAaware EPONs and provide a good protection of offered quality of service against interference from other sources.

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.

The digital home environment creates business opportunities for various firms. However, the growing complexity and management workload of home systems is leading to degrading usability. In this paper, we discuss the business dynamics of the digital home environment. We suggest that lower usability will slow down the adoption of digital services, and therefore we present a novel view that focuses the attention on management of digital homes. We explain the management hierarchy of the home environment, and construct four scenarios that describe the possible directions of evolution. Throughout the paper, we pay special attention to broadband access operators, since we consider them strong candidates for becoming management service providers. Therefore, we present possible management-related business models that broadband access operators could use when formulating their business strategies. Our analysis shows that management service provision is an important business driver.

Since the first community antenna television (CATV) system was deployed in 1948, cable technology has advanced at an astounding rate. Today, multiple service providers (MSOs) are competing with telephone companies to deliver the long sought 'triple play' of voice, video and data to residential and business premises. Upstream data rates have progressed from dial-up speeds to 10Mbps and to 100s of Mbps in the near future. While there are competing standards, the Data over Cable Service Interface Specification (DOCSIS) has emerged as the single MAC and physical layer standard. We have developed a model of DOCSIS using the 'ns' simulation package. In this tutorial paper we provide a detailed presentation of the DOCSIS protocol. To provide a deeper understanding of DOCSIS, we present the results of a simulation analysis focusing on the impact that DOCSIS has on TCP applications. The objectives of this tutorial are: 1)to provide an overview of the DOCSIS protocol; 2)to present the 'ns' simulation model; 3)to present preliminary upstream contention and downstream transmission queuing network models (QNMs).

t is common knowledge that over the last decade there has been a major boost in communication networks. In fact, the development of high-performance backbone networks was immediately followed by the rapid dissemination of broadband wired access technologies, such as leased lines based on fiber-optic links, cable modems using coaxial systems, and digital subscriber line (xDSL) access networks. This gave users a whole new class of services that exploit the increasing number of available network resources. Many new services are based on multimedia applications, such as voice over IP (VoIP), video conferencing, video on demand (VoD), massive online gaming, and peer-to-peer. Unlike traditional TCP/IP services, multimedia applications usually require strict network guarantees such as reserved bandwidth or bounded delays.

In the recent past, there has been a tremendous increase in the popularity of VoIP services as a result of huge growth in broadband access. The same VoIP service poses new challenges when deployed over a wireless mesh network while enabling users to make voice calls using WiFi phones. Packet losses and delay due to interference in a multiple hop mesh network with limited capacity can significantly degrade the end-to-end VoIP call quality.

Wireless Internet-access technologies have significant market potential, particularly the Worldwide Interoperability for Microwave Access (WiMAX) protocol which can offer data rates of tens of megabits per second. A significant demand for embedded high-performance WiMAX solutions is forcing designers to seek single-chip multicore systems that offer competitive advantages in terms of all performance metrics, such as speed, power, and area. Through the provision of a degree of flexibility similar to that of a DSP and performance and power consumption advantages approaching that of an application-specific integrated circuit, emerging dynamically reconfigurable (DR) processors are proving to be strong candidates for processing cores in future highperformance multicore-processor systems. This paper presents several new single-chip multicore architectures for the WiMAX application based on recently emerging coarse-grained DR processor cores. A simulation platform is proposed in order to explore and implement various multicore solutions combining different memory architectures and task-partitioning schemes. This paper describes the different architectures, the simulation environment, and several task-partitioning methods and demonstrates that up to 7.3 and 12 times speedup can be achieved by employing eight and ten DR processor cores for both the WiMAX transmitter and receiver sections, respectively. A comparison with other WiMAX multicore solutions is given in order to demonstrate that our best solution delivers a high throughput at relatively low area cost.

The hybrid wireless-optical broadband-access network (WOBAN) is a promising architecture for future access networks. Recently, the wireless part of WOBAN has been gaining increasing attention, and early versions are being deployed as municipal access solutions to eliminate the wired drop to every wireless router at customer premises. This architecture saves on network deployment cost because the fiber need not penetrate each end-user, and it extends the reach of emerging optical-access solutions, such as passive optical networks. This paper first presents an architecture and a vision for the WOBAN and articulates why the combination of wireless and optical presents a compelling solution that optimizes the best of both worlds. While this discussion briefly touches upon the business drivers, the main arguments are based on technical and deployment considerations. Consequently, the rest of this paper reviews a variety of relevant research challenges, namely, network setup, network connectivity, and fault-tolerant behavior of the WOBAN. In the network setup, we review the design of a WOBAN where the back end is a wired optical network, the front end is managed by a wireless connectivity, and, in between, the tail ends of the optical part [known as optical network unit (ONU)] communicate directly with wireless base stations (known as "gateway routers"). We outline algorithms to optimize the placement of ONUs in a WOBAN and report on a survey that we conducted on the distribution and types of wireless routers in the Wildhorse residential neighborhood of North Davis, CA. Then, we examine the WOBAN's routing properties (network connectivity), discuss the pros and cons of various routing algorithms, and summarize the idea behind fault-tolerant design of such hybrid networks.

This chapter starts by presenting the Stanford University Interim (SUI) and modified Friis propagation models. Although the SUI model is being recommended for WiMAX, the comparison between the model and experimental results show that, in our environment, at 3.5 GHz, the modified Friis model with g = 3 fits better the measurement values. From the analyses of the signal-to-noise-plus-interference ratio, SNIR, interference-to-noise ratio and reuse pattern, it is found that both noise and interference present a strong limitation to the performance of fixed WiMAX, mainly for higher order modulation and coding schemes (MCSs). In general terms, the use of sectorization in fixed WiMAX enables to reduce the reuse pattern while considering sub-channelisation allows for improvement on the coverage. The reduction of the reuse pattern directly corresponds to an increase in the system capacity but the improvement in the coverage range (through sub-channelisation) can also allow for an improvement in UL system capacity, as adaptive MCS are used. Two different approaches are considered for graphical cellular planning, and the district of Covilhã is considered as a case study. On the one hand, one considered a GIS based WiMAX planning tool conceived by considering coverage issues, frequency reuse, and the impact of the different classes of service. On the other, Winprop™ is used as it distinguishes among different MCS in the graphical presentation of the results. Both tools consider the information coming from the digital terrain profile. The GIS functionalities allow for appropriately adjusting azimuth and tilt of antennas. This cellular planning exercises confirm the results of theoretical analysis, where different crowns are achieved for the coverage with each MCS (corresponding to a given range of values for SNIR), for the maximum physical throughput, and for the “best server“ cells. The frequency radio resources should be considered as the most valuable resource during the planning of wireless broadband access networks. As a rule, spectral efficiency needs to be optimized by using several advanced techniques, corresponding to an optimization from the cost-benefit point of view.

The standardization of a Return Channel via Satellite (DVB-RCS) and satellite community efforts in term of interoperability over the last few years lead to quite a positive outcome: Geostationary satellite networks are intended to provide broadband access to interactive multimedia services in low infrastructure areas. However, in order to take in account real-time multimedia traffic, an efficient resource management scheme is still necessary to maximize the scarce uplink capacities usage.

This paper presents a smart collection of existing technologies to provide low-cost satellite delivery of triple-play services to the home with a TVcentric terminal. The satellite connections provides the best and quickest solution to reduce the digital divide in less-favored areas, which has been considered as a major issue in the diffusion of broadband access. The platform employs DVB-S(2) and DVB-RCS technologies in the forward and the return link, respectively. The flexible framing structure of DVB-S2 and the adoption of the Adaptive Coding & Modulation (ACM) functionality allow an efficient exploitation of the satellite resource. The paper provides a description of the TV-Centric services, the required QoS and the relevant system architecture.

The recent developments in the fixed and mobile telecommunication industry, namely the rapid penetration of broadband access and new charging models in the broadband market in conjunction with the success of wireless local area networks and the general trend of fixed and mobile convergence, are transforming the telecommunication landscape. One of the main challenges is to integrate the fixed and mobile technologies in a way that leverages the strengths of different technologies and improves the service experience for the end user. A crucial step for this transformation is to provide adequate support for users to seamlessly switch between network domains and technologies. The main contribution of this paper is a solution that allows a mobile terminal to change from the mobile radio access to the fixed/cable access provided over a local wireless network or vice versa without disrupting an active ongoing voice call. The implementation of the proposed solution was tested and evaluated in an experimental network with real voice calls.

WIMAX signal throughput and area coverage range are the most important factors that will affect the quality of broadband access services in mobile systems. This paper presents a comprehensive study of frequency analysis for path loss on mobile WIMAX presented to achieve large throughput and wide coverage to a big number of users. In this paper we have calculated the path loss values based on the variation of WIMAX standard frequency in the range of 2 to 6 GHz, and a fixed distance of 5 km from the transmit station to the receive station in urban, suburban, rural and free space environments. The paper discusses and implements Okumura, Hata, Cost-231, Ericsson, Erceg, Walfish, Ecc-33, Lee and the simplified free space path loss models. All the models applied in this paper are used to predict the propagation loss for WIMAX.

Ethernet-based passive optical network (EPON) technology is being considered as a promising solution for next-generation broadband access network due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure. A major feature for this new architecture is the use of a shared transmission media between all users; hence, medium access control arbitration mechanisms are essential for the successful implementation of EPON: i.e., ensure a contention-free transmission and provide end users with an equal access to the shared media. In this paper, we propose to use the multipoint control protocol defined within the IEEE 802.3ah Task Force to arbitrate the transmission of different users, and we present different dynamic bandwidth allocation (DBA) algorithms to effectively and fairly allocate bandwidths between end users. These DBA algorithms are also augmented to support differentiated services: a crucial requirement for a converged broadband access network with heterogeneous traffic. We show that queueing delays under strict bandwidth allocation algorithms results in an unexpected behavior for certain traffic classes, and we suggest the use of DBA with appropriate local queue management to alleviate this inappropriate behavior. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed protocols.

Emerging broadband access technologies such as 802.11 are enabling the introduction of wireless IP services to an increasing number of users. The market forecasts suggest that a new class of network providers, commonly referred to as Wireless Internet Service Providers (WISP), will deploy public wireless networks based on these new technologies. In order to offer uninterrupted IP service combined with ubiquitous seamless mobility, these multi-provider networks need to be integrated with each other, as well as with wide-area wireless technologies, such as thirdgeneration CDMA-2000 and UMTS. Therefore, efficient authentication and dynamic key exchange protocols that support heterogeneous domains as well as networks with roaming agreements across trust boundaries are key to the success of wide-area wireless IP infrastructures. In this paper, we first describe a simple network model that accounts for heterogeneity in network service providers, and put forward the requirements that any authentication and key exchange protocol that operates in such model should satisfy, in terms of network efficiency, security and fraud prevention. We then introduce a new authentication and key exchange protocol, called Wireless Shared Key Exchange (W-SKE). We characterize properties and limitations of W-SKE against the requirements discussed earlier. Finally, we contrast W-SKE against other wellknown and emerging approaches.

The Hybrid Fiber Coax (HFC) is a modern broadband access network, providing advanced interactive services such as Internet access, digital interactive television and cable telephony. The edge costs dominate the cost of launching new services, at the time of deployment (CapEx) as well as for maintenance (OpEx). Therefore next-generation edge devices aim at the convergence of these services and their platforms into a single multi-service infrastructure, thus sharing resources and bandwidth. The focus of this paper is on the HFC access network design for bandwidth-intensive TV services, bringing standard as well as switched broadcast technologies into play. Standard broadcast TV service deployments, offered through the Digital Video Broadcast (DVB) platform, require low installation costs, but the bandwidth consumption increases linearly with the number of available TV channels, even for very unpopular channels. Switched broadcast TV channels, offered on the (Euro-) DOCSIS platform together with other interactive unicast services such as Video on Demand, are only streamed to a node on the HFC access network if they are requested locally, thus limiting bandwidth consumption for less popular channels. We present an access network design tool, based on an analytical TV traffic model, minimizing the installation cost on the edge devices and study the influence of the most important traffic and content parameters.

Radio-over-Fiber (RoF) is a promising technology to fulfill future broadband access requirements with reliability, transparency and flexibility. We propose bi-directional RoF system with high RF carrier support. Downlink scheme utilizes optical frequency up-conversion while uplink scheme is based on electrical frequency down-conversion. For downlink, an unmodulated microwave band signal, f LO electrically combined with DPSK encoded digital data stream sub-carrier modulated at intermediate frequency (IF) is intensity modulated at an optical carrier, λ IF in Control Station. An un-modulated high frequency carrier, Local Oscillator (LO) is also modulated over separate wavelength, λ LO at CS. At remote node (RN), semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) is used for photonic mm-wave mixing (between λ IF and λ LO) and frequency up-conversion. After photo-detection at BS of optical channel modulated with up-converted RF signal, λ RF upconverted downlink data signal at high RF (f RF) is extracted, down-converted to IF, de-modulated and tested for BER. During mixing process at RN, f LO also gets up-converted and modulated over wavelength λ RF. For uplink, data at high RF is downconverted to IF at BS by extracting and using up-converted f LO from downlink electrical signal. Further wavelength re-use concept was employed for uplink where down-converted uplink signal is modulated over extracted optical carrier (from downlink signal) and transmitted to CS. Hence, it does not require sending separate optical LO, λ LO to each BS. Cost-effective bi-directional solution is proposed with acceptable performance measures by employing wavelength reuse and remote LO delivery concepts.

The IEEE 802.16 provides wireless broadband access for Metropolitan Area Networks (MAN). Due to support for mobility and high bandwidth, it has captured everyone's attention. Cost of the deploying IEEE 802.16 equipment is high, so, it is vital that the network is simulated before deployment. This paper presents the design of 802.16 MAC simulator which implements true frame format, with TDM / TDMA and TDD. QoS and Admission control is also simulated by designing Bandwidth and Service Flow Managers. Simulation topology for a typical wireless network is also presented.