WiBACK: A back-haul network architecture for 5G networks

Recently both academic and industry worlds has started to define the successor of Long Term Evolution (LTE), so-called 5G networks, which will most likely appear by the end of the decade. It is widely accepted that those 5G networks will have to deal with significantly more challenging requirements in terms of provided bandwidth, latency and supported services. This will lead to not only modifications in access and parts of core networks, but will trigger changes throughout the whole network, including the Back-haul segment. In this work we present our vision of a 5G Back-haul network and identify the associated challenges. We then describe our Wireless Backhaul (WiBACK) architecture, which implements Software Defined Network (SDN) concepts and further extends them into the wireless domain. Finally we present a brief overview of our pilot installations before we conclude.This work has been supported by the BATS research project which is funded by the European Union Seventh Framework Programme under contract n317533

Topology forming and optimization framework for heterogeneous wireless back-haul networks supporting unidirectional technologies

Wireless operators, in developed or emerging regions, must support triple-play service offerings as demanded by the market or mandated by regulatory bodies through so-called Universal Service Obligations (USOs). Since individual operators might face different constraints such as available spectrum licenses, technologies, cost structures or a low energy footprint, the EU FP7 CARrier grade wireless MEsh Network (CARMEN) project has developed a carrier-grade heterogeneous multi-radio back-haul architecture which may be deployed to extend, complement or even replace traditional operator equipment. To support offloading of live triple-play content to broadcast-optimized, e.g., DVB-T, overlay cells, this heterogeneous wireless back-haul architecture integrates unidirectional broadcast technologies. In order to manage the physical and logical resources of such a network, a centralized coordinator approach has been chosen, where no routing state is kept at plain WiBACK Nodes (WNs) which merely store QoS-aware MPLS forwarding state. In this paper we present our Unidirectional Technology (UDT)-aware design of the centralized Topology Management Function (TMF), which provides a framework for different topology and spectrum allocation optimization strategies and algorithms to be implemented. Following the validation of the design, we present evaluation results using a hybrid local/centralized topology optimizer showing that our TMF design supports the reliable forming of optimized topologies as well as the timely recovery from node failures.Federal Ministry of Education and Research of the Federal Republic of German (F¨orderkennzeichen 01 BU1116,SolarMesh Energieeffizientes,autonomesgroßfl¨achiges Sprach- undDatenfunknetzmitflacher IP-Architektur

Path signalling in a wireless back-haul network integrating unidirectional broadcast technologies

The black-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, in our previous work, we have developed a cost-effective heterogeneous layer 2.5 wireless back-haul (WiBACK) architecture, which leverages the native multicast capabilities of broadcast technologies such as DVB to off-load high-bandwidth broadcast content delivery. Furthermore, our architecture provides support for unidirectional technologies on the data and the control plane. This adopts a centralized coordinator approach, in which coordinator nodes install so-called management and data pipes. No routing state is kept at plain WiBACK nodes, which merely store QoS-aware pipe forwarding state. Consequently, the architecture requires a reliable protocol to push resource allocation and pipe forwarding state into the network, considering possibly unidirectional connectivity. Such a protocol, whose task is related to MPLS label distribution, is essential during the initial forming of WiBACK topologies and during regular network operations to reliably manage the data pipes. In this paper, we present a novel approach to extend our IEEE 802.21-inspired WiBACK TransportService and, based upon this, the design of an RSVP-TE-style pipe signalling protocol using nested hop-by-hop request/response MIH transactions that supports signalling over unidirectional technologies. A thorough evaluation and successful testbed deployments show that this protocol reliably signals pipe state even under high loss conditions

Towards QoS-aware load distribution in heterogeneous networks

Enabling broadband internet connectivity of 30 mbps and more is an ambiguous goal of the European Digital Agenda, particularly in rural and remote regions. Not relying on a single access technology but using multiple simultaneously is believed to be a promising option to meet this objective. However, simply using the available connections in parallel and distributing traffic arbitrarily among them despite their different characteristics might still lead to an unacceptable service quality due to the heterogeneity. Instead, methods that are sophisticated are required, which on one hand takes the Quality-of-Service (QoS) requirements of the various applications into account and on the other hand is aware of the different network characteristics. In this work, we discuss the main challenges which occur when utilizing multiple access technologies in parallel and we propose an architecture addressing those issues. Moreover, we present some preliminary validation results, which show the benefit of our approach.The BATS research project which is funded by the European Union Seventh Framework Programme under contract n31753

QoS Provisioning in Converged Satellite and Terrestrial Networks: A Survey of the State-of-the-Art

It has been widely acknowledged that future networks will need to provide significantly more capacity than current ones in order to deal with the increasing traffic demands of the users. Particularly in regions where optical fibers are unlikely to be deployed due to economical constraints, this is a major challenge. One option to address this issue is to complement existing narrow-band terrestrial networks with additional satellite connections. Satellites cover huge areas, and recent developments have considerably increased the available capacity while decreasing the cost. However, geostationary satellite links have significantly different link characteristics than most terrestrial links, mainly due to the higher signal propagation time, which often renders them not suitable for delay intolerant traffic. This paper surveys the current state-of-the-art of satellite and terrestrial network convergence. We mainly focus on scenarios in which satellite networks complement existing terrestrial infrastructures, i.e., parallel satellite and terrestrial links exist, in order to provide high bandwidth connections while ideally achieving a similar end user quality-of-experience as in high bandwidth terrestrial networks. Thus, we identify the technical challenges associated with the convergence of satellite and terrestrial networks and analyze the related work. Based on this, we identify four key functional building blocks, which are essential to distribute traffic optimally between the terrestrial and the satellite networks. These are the traffic requirement identification function, the link characteristics identification function, as well as the traffic engineering function and the execution function. Afterwards, we survey current network architectures with respect to these key functional building blocks and perform a gap analysis, which shows that all analyzed network architectures require adaptations to effectively support converged satellite and terrestrial networks. Hence, we conclude by formulating several open research questions with respect to satellite and terrestrial network convergence.This work was supported by the BATS Research Project through the European Union Seventh Framework Programme under Contract 317533

Noise Impacts from Professional Dog Grooming Forced-Air Dryers

This study was designed to measure the sound output of four commonly used brands of forced-air dryers used by dog groomers in the United States. Many dog groomers have questions about the effect of this exposure on their hearing, as well as on the hearing of the dogs that are being groomed. Readings taken from each dryer at 1 meter (the likely distance of the dryer from the groomer and the dog) showed average levels ranging from 105.5 to 108.3 dB SPL or 94.8 to 108.0 dBA. Using the 90 dBA criterion required by the US Occupational Safety and Health Administration, dog groomers/bathers are at risk if exposure to the lowest intensity dryer (94.8 dBA) exceeds 4 hours per day. If the more stringent 85 dBA criterion and 3 dB tradeoff is applied, less than one hour of exposure is permissible in an 8 hour day. Cautions are recommended for any persons exposed to noise from forced-air dryers

A free-standing LiFePO<inf>4</inf>-carbon paper hybrid cathode for flexible lithium-ion batteries

© 2016 The Royal Society of Chemistry. Lithium-ion batteries (LIBs) are widely implemented to power portable electronic devices and are increasingly in demand for large-scale applications. One of the major obstacles for this technology is still the low cost-efficiency of its electrochemical active materials and production processes. In this work, we present a novel impregnation-carbothermal reduction method to generate a LiFePO4-carbon paper hybrid electrode, which doesn't require a metallic current collector, polymeric binder or conducting additives to function as a cathode material in a LIB system. A shell of LiFePO4 crystals was grown in situ on carbon fibres during the carbonization of microcrystalline cellulose. The LiFePO4-carbon paper electrode achieved an initial reversible areal capacity of 197 μA h cm-2 increasing to 222 μA h cm-2 after 500 cycles at a current density of 0.1 mA cm-2. The hybrid electrode also demonstrated a superior cycling performance for up to 1000 cycles. The free-standing electrode could be potentially applied for flexible lithium-ion batteries

High precision 89^{89}Y(α\alpha,α\alpha)89^{89}Y scattering at low energies

Elastic scattering cross sections of the $^{89}$Y($\alpha$,$\alpha$)$^{89}$Y reaction have been measured at energies E$_{c.m.}$ = 15.51 and 18.63 MeV. The high precision data for the semi-magic $N = 50$ nucleus $^{89}$Y are used to derive a local potential and to evaluate the predictions of global and regional $\alpha$-nucleus potentials. The variation of the elastic alpha scattering cross sections along the $N = 50$ isotonic chain is investigated by a study of the ratios of angular distributions for $^{89}$Y($\alpha$,$\alpha$)$^{89}$Y and $^{92}$Mo($\alpha$,$\alpha$)$^{92}$Mo at E$_{c.m.} \approx$ 15.51 and 18.63 MeV. This ratio is a very sensitive probe at energies close to the Coulomb barrier, where scattering data alone is usually not enough to characterize the different potentials. Furthermore, $\alpha$-cluster states in $^{93}$Nb = $^{89}$Y $\otimes$ $\alpha$ are investigated

Prognostic features for quality of life after radical cystectomy and orthotopic neobladder

Purpose: To analyse prognostic features on quality of life (QoL) following radical cystectomy and urinary diversion via orthotopic neobladder in a single-centre patient cohort. Materials and Methods: Postoperative QoL of 152 patients was assessed retrospectively using the validated QLQ-C30 questionnaire. Potential associations of patient's quality of life including pre-and intraoperative characteristics, surgeon experience, postoperative time course, adjuvant therapies, and functional outcome were defined a priori and evaluated. Mann-Whitney-U-, Kruskal-Wallis-, Spearman correlation and post hoc-testing were used. A multivariate analysis using a multiple logistic regression model was performed. A p value 100 previous cystectomies, p=0.007), and nerve-sparing surgery (p=0.001). Patients who underwent secondary chemotherapy or radiotherapy had significant lower QLQ-C30 scores (p=0.04, p=0.02 respectively). Patients who were asymptomatic had a significantly higher quality of life (p= 100 vs. <100 previous cystectomies, p=0.021), and daytime continence (p=0.032). Conclusion: In the present study, we report health-related QoL outcomes in a contemporary patient cohort and confirm preoperative ECOG status, surgeon experience and daytime incontinence as independent prognostic features for a good postoperative QoL