Abstract

The call for papers resulted in a high number of submis- sions, from which we have been able to select 12 excellent papers dealing with the different aspects of satellite commu- nications and navigation. Multiple-input multiple-output (MIMO) techniques are attracting a considerable amount of attention from within the terrestrial wireless community. The first paper of this spe- cial issue, “Multisatellite MIMO communications at Ku band and above: investigations on spatial multiplexing for capac- ity improvement and selection diversity for interference mit- igation,” considers the application of such technology over a satellite platform operating in the Ku band and above. The paper considers how MIMO can be used to increase capac- ity by using a satellite spatial multiplexing system and how antenna selection can be used to mitigate interference. The next paper “Investigations in satellite MIMO channel model- ing: accent on polarization” looks at MIMO systems from the polarization diversity point of view and dwells on the satellite cooperative communication concepts. Switch and stay combining (SSC) is a form of diversity technique used in digital receivers to compensate for fade events introduced by the mobile channel. The third paper “Performance analysis of SSC diversity receivers over corre- lated Ricean fading satellite channels” investigates the per- formance of dual-branch SSC receivers for different fading channel characteristics. The next four papers deal with the emerging scenario of mobile digital video broadcasting (DVB-S2 and RCS mo- bile). Alternative approaches to counteracting fading chan- nels introduced when operating in a train environment re- ceiving satellite DVB-S2 are presented in the paper “Ad- vanced fade countermeasures for DVB-S2 systems in railway scenarios.” Here, as a result of simulation analysis, antenna diversity and packet-level forward error correction mecha- nisms are proposed and their impact is evaluated with respect to the receiver design and system complexity. The theme of DVB-S2 is continued with the paper “Capacity versus bit er- ror rate trade-off in the DVB-S2 forward link,” which inves- tigates how satellite capacity can be optimised for DVB-S2 transmissions. The DVB return channel via satellite (DVB- RCS) is then addressed in “Frequency estimation in iterative interference cancellation applied to multibeam satellite sys- tems,” which considers the application of interference cancel- lation on the reverse link of a multibeam satellite system, us- ing DVB-RCS with convolutional coding as an example. The paper “A QoS architecture for DVB-RCS next-generation satellite networks” proceeds to design and emulate a quality- of-service (QoS) architecture that demonstrates using real multimedia applications how QoS can be supported over a DVB-RCS network. 2 EURASIP Journal on Wireless Communications and Networking Synchronization aspects are dealt with in “Maximum likelihood timing and carrier synchronization in burst-mode satellite transmissions.” The paper addresses the problem of achieving synchronisation for a burst-mode satellite trans- mission over an AWGN channel. The subject of burst trans- mission continues with the paper “Burst format design for optimum joint estimation of Doppler-shift and Doppler- rate in packet satellite communications,” which considers optimising the burst-format of packet-oriented transmis- sions by proposing very-low-complexity algorithms for car- rier Doppler-shift and Doppler-rate estimation. A network comprising satellite and high-altitude plat- forms is considered in the paper “TCP-call admission con- trol interaction in multiplatform space architectures.” Cross- layer techniques are implemented by means of TCP feeding back into call admission control (CAC) procedures for the purpose of prevention of congestion and improvement in QoS. Finally, since navigation is an extremely important part of the satellite system family, we have included two papers. The first paper “Efficient delay tracking methods with side- lobes cancellation for BOC-modulated signals” deals with bi- nary offset carrier (BOC) modulation, which is adopted in typical navigation systems. The paper considers how to improve the tracking of the main lobe of the BOC-modulated signal by using sidelobe suppression techniques. An alternative approach based on filter bank processing is presented in “Analysis of filter-bank-based methods for fast serial acqui- sition of BOC-modulated signals” to conclude the special issue. Document type: Part of book or chapter of book

Abstract

The inflexibility and rigidity of the current networking systems in light of the growing number of computing devices that connected to the Internet has led to the need of a new generation of computer networks. In this context, software-defined network has recently emerged as one of the most recognisable solutions to facilitate the network management and decrease the complexity through detaching the control layer from network appliances. Since, each new technology accompanied with new issues and concerns, one of the main challenges that facing the SDNs is the fault tolerance and resilience. Although there are a numerous of studies that have discussed this issue, the after failure repair scenario is remained unclear and have not addressed well yet. For this reason, we specify this paper as a step forward to address the issue of routing changes, which is important for utilising the optimal paths after failure repair. We produced a new network model as well as a compatible framework with SDN architecture to fulfil the routing changes activity. The consequence is estimated based on an analytical model and finally, a case study example is provided in order to conceptualise the concept. Document type: Part of book or chapter of book

Abstract

The data demands and economics surrounding IP internetworking are such that IP routers are now connecting directly to SDH or DWDM systems. As such, many of the traditional mechanisms used to engineer the traffic over the physical infrastructure are no longer available. Consequently a new approach is required. This paper outlines a set of mechanisms and procedures, including enhancements to the layer 3 routeing and signalling protocols ad MPLS forwarding that, when combined, provide the capabilities to provide traffic engineering capabilities in an optical IP environment. Document type: Book

Abstract

This paper describes the £ 120M UK 'e-Science' (http://www.research-councils.ac.uk/and http://www.escience-grid.org.uk) initiative and begins by defining what is meant by the term e-Science. The majority of the £ 120M, some £ 75M, is funding large-scale e-Science pilot projects in many areas of science and engineering. The infrastructure needed to support such projects must permit routine sharing of distributed and heterogeneous computational and data resources as well as supporting effective collaboration between groups of scientists. Such an infrastructure is commonly referred to as the Grid. Apart from £ 10M towards a Teraflop computer, the remaining funds, some £ 35M, constitute the e-Science 'Core Programme'. The goal of this Core Programme is to advance the development of robust and generic Grid middleware in collaboration with industry. The key elements of the Core Programme will be outlined including details of a UK e-Science Grid testbed. The pilot e-Science projects that have so far been announced are then briefly described. These projects span a range of disciplines from particle physics and astronomy to engineering and healthcare, and illustrate the breadth of the UK e-Science Programme. In addition to these major e-Science projects, the Core Programme is funding a series of short-term e-Science demonstrators across a number of disciplines as well as projects in network traffic engineering and some international collaborative activities. We conclude with some remarks about the need to develop a data architecture for the Grid that will allow federated access to relational databases as well as flat files.

Abstract

With the expected surge in the global IP traffic, service providers would need to adapt accordingly to operate disruption and loss free networks supported with the developing IP infrastructure. With the disposal of the hierarchical network structure, radio access networks are moving towards a flat-IP architecture and novel topological set-ups in the backhaul. Hence, a routing paradigm that employs suitable Traffic Engineering (TE) techniques aligned with the developing nature of future access networks must be applied. In this paper, Multi-Plane Routing (MPR) that consolidates various aspects in all-IP infrastructure is remodelled in consistent with this development. We propose a MPR-based TE approach considering two different scenarios to reflect the evolution in the architectural design of access network structures under a realistic traffic scenario with a varying range of internal/external traffic. Accordingly, a practical performance evaluation testing the validity of the aforementioned scenarios is presented. Our simulation results demonstrate a better achieved performance under the flat-IP structure in addition to MPR-based methods' superiority over legacy OSPF/Invcap. Performance degradation is observed with the rise in the internal traffic distribution for the different scenarios studied. Moreover, a new optimization framework for the offline and online TE mechanisms of MPR have been proposed.

Abstract

In this era of ubiquitous computing, coupled with the emergence of big data and internet of things, there have been constant changes in every aspect of cloud data center communications - its network connectivity, data storage, data transfer, and architectural design. As a result of this, the amount of data transferable, and the frequency of data transfer have tremendously increased; causing device failures and traffic congestions. To cope with these changes so that performance can be sustained amidst device failures and traffic congestion, the design of fault tolerant cloud data center is important. A fault tolerant cloud data center network should be able to provide alternative paths from source to destination during failures so that there will not be abrupt fall in performance. But still with the ongoing researches in this regard, there has not been a robust cloud data center design that can boast of being suitable for alleviating the poor fault tolerance of cloud data center. In this paper, we proposed the improved versions of fat-tree interconnection hybrid designs derived from the structure called Z-fat tree; to address the issues of fault tolerance. Then, we compared these designs with single fat tree architecture with the same amount of resources for client server communication pattern such as Email application in a cloud data center. The simulation results obtained based on failed switches and links, show that our proposed hybrid designs outperformed the single fat tree design as the inter arrival time of the packets reduces.

Abstract

In this paper, we present a deep neural network based real-time integrated framework to detect objects, lane markings, and drivable space using a monocular camera for advanced driver assistance systems. The object detection framework detects and tracks objects on the road such as cars, trucks, pedestrians, bicycles, motorcycles, and traffic signs. The lane detection framework identifies the different lane markings on the road and also distinguishes between the ego lane and adjacent lane boundaries. The free space detection framework estimates the drivable space in front of the vehicle. In our integrated framework, we propose a pipeline combining the three deep neural networks into a single framework, for object detection, lane detection, and free space detection simultaneously. The integrated framework is implemented in C++ and runs real-time on the Nvidia's Drive PX 2 platform.

Abstract

Energy expenses are becoming an increasingly important fraction of data center operating costs. At the same time, the energy expense per unit of computation can vary significantly between two different locations. In this paper, we characterize the variation due to fluctuating electricity prices and argue that existing distributed systems should be able to exploit this variation for significant economic gains. Electricity prices exhibit both temporal and geographic variation, due to regional demand differences, transmission inefficiencies, and generation diversity. Starting with historical electricity prices, for twenty nine locations in the US, and network traffic data collected on Akamai's CDN, we use simulation to quantify the possible economic gains for a realistic workload. Our results imply that existing systems may be able to save millions of dollars a year in electricity costs, by being cognizant of locational computation cost differences. Nokia Corporation National Science Foundation (U.S.) (Grant CNF–0435382) Document type: Conference object

Abstract

Cities have become the most common living environment for humans. With this rising urbanization, urban design has become vital for these growing cities. While measuring objective data like traffic congestion or air quality is important, it does not tell the whole story of how people live in the cities or how cities should be developed to make them more livable. In future for a true smart city a more humane component is needed to understand how the population of cities actually interact with and feel about their surroundings. Surveys are a great and a necessary tool for this and they are already being used in the design process. However, they require effort and and a lot of silent information can be missed. The surveying process also doesn't happen in real time. We suggest that social media data could be used to gather more information about human- environment interaction in cities and compliment the surveys. We show a working prototype of a tool that creates an emotional map of a city by mining social media data for sentiments and heatmapping them. This kind of method could prove to be an useful tool for urban designers, who could take advantage of the visual intuition of humans and see instantly where and how emotional hotspots arise. It could also be of interest for emotion researchers, who could get data on what it really means to be happy for a human being - for example eating an ice cream at the beach - instead of only linking conceptual words (such as happy) to external stimuli (such as smiling). Peer reviewed

Abstract

Several major Internet service providers (e.g., Level-3, AT&T, Verizon) today also offer content distribution services. The emergence of such "Network-CDNs" (NCDNs) are driven by market forces that place more value on content services than just carrying the bits. NCDNs are also necessitated by the need to reduce the cost of carrying ever-increasing volumes of traffic across their backbones. An NCDN has the flexibility to determine both where content is placed and how traffic is routed within the network. However NCDNs today continue to treat traffic engineering independently from content placement and request redirection decisions. In this paper, we investigate the interplay between content distribution strategies and traffic engineering and ask how an NCDN should engineer traffic in a content-aware manner. Our experimental analysis, based on traces from a large content distribution network and real ISP topologies, shows that effective content placement can significantly simplify traffic engineering and in most cases obviate the need to engineer NCDN traffic all together! Further, we show that simple demand-oblivious schemes for routing and placement such as InverseCap and LRU suffice as they achieve network costs that are close to the best possible. Comment: 12 pages, 13 Figure