It has been widely acknowledged that future networks need to provide significantly more capacity than nowadays' ones in order to deal with the increasing traffic demands of the users. Particularly in regions where optical fiber are unlikely to be deployed due to economical constraints, this is a huge 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 the cost are decreasing. 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 article 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.

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Rural areas all over the world often lack affordable broadband Internet connectivity. This is particularly, but not solely, true for developing and emerging countries. Also rural areas in western countries share similar problems of high capital expenditure (CAPEX) and especially operational expenditure (OPEX) due to vast and sparsely populated areas, which often present an uneconomical environment for deploying traditional wireless carrier equipment. To address these issues, we have developed a carrier-grade heterogeneous multi-radio back-haul architecture which may be deployed to extend, complement or even replace traditional operator equipment. Our Wireless Back-Haul (WiBACK) technology extends the back-haul coverage by building on cost-effective and low-power equipment while still allowing for effective Quality of Service (QoS)-provisioning. In this paper we first present a pilot scenario in Hennef-Theishohn, Germany, where the residents of a remote farm are provided with broadband Internet connectivity using a long-distance, multi-hop WiBACK network. We evaluate the QoS-related performance of this network and show that we can meet QoS demands one expects from a carrier-grade network even under heavy load conditions

Wireless operators, in developed or emerging regions, must support the triple-play service offerings demanded by the market or by regulatory bodies through so-called Universal Service Obligations (USOs). The same USO often also requires the coverage of a large percentage of the population, which especially in emerging regions lives in vast rural areas outside the larger cities. Since individual operators might have different requirements such as available spectrum licenses or technologies, we have developed a carrier-grade heterogeneous multi-radio back-haul architecture which may be deployed to extend, complement or even replace traditional operator equipment. This Wireless Back-Haul (WiBACK) architecture integrates broadcast technologies to off-load the distribution of live content, such as TV or radio, to longer range, e.g. DVB-T, overlay cells. Therefore, the WiBACK architecture provides a cost-effective low-power alternative to extend the wireless back-haul coverag e in urban, but especially in rural and previously unconnected areas. 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 design of the centralized Topology Management Function (TMF) and its ring-based approach, validate its functionality and evaluate the performance for dense and sparse topologies

Rural areas especially in emerging countries often lack affordable broadband Internet connectivity. This 'digital divide' limits the access to knowledge, government services or health care. The major limiting factors are seen in the CAPEX and especially the OPEX related to traditional wireless carrier equipment, its relatively large energy footprint, the vast and sparsely populated areas and the low revenues to be collected. Since in many rural regions access to a power grid may not be available or highly instable, ensuring a 24/7 operation of a cell site is a very costly task. To address these issues we have developed a carrier-grade heterogeneous multi-radio backhaul architecture which may be deployed as an alternative to traditional operator equipment. As integral part of Detecon's PeopleConnect eKiosk business model, Fraunhofer FOKUS' Wireless Back-Haul (WiBACK) network technology provides punctual wireless back-haul connectivity while building on cost-effective and low-power equipment. In this paper we present a pilot scenario in Maseru, Lesotho, where an entrepreneur starts out with three WiBACK-connected eKiosk sites with the goal of providing broadband Internet access to incrementally larger parts of Maseru over time.

Abstract-Monitoring is a crucial task in QoS-aware networks since it provides statistics to verify that the network performs within the committed QoS parameters. It is especially important in a resource-constrained Carriergrade Wireless Mesh Access Network (CG-WMAN) in order to monitor a node's neighborhood, established links as well as MPLS QoS-traffic flows, so-called Label-Switched Paths (LSPs). In this paper, we present a monitoring architecture for LSPs in a heterogeneous CG-WMAN, where configurable Rating Agents perform adaptive per-LSP event creation based on monitoring statistics, QoS-requirements and overall network state. Keeping the footprint of the monitoring mechanism at a minimum, our approach is based on quasipassive monitoring minimizing the transmission of extra frames. To support unidirectional links as well as 1-to-N multicast trees, a receiving side feedback-free mechanism is proposed which can be extended with transmitting side functionality. Initial results obtained in our testbed show that we can reliably detect under-performing links according to the QoS requirements of the payload.

Whilst broadband Internet connectivity has become highly important, providing broadband connectivity nonetheless remains a considerable challenge, particularly in rural and remote regions where the deployment of optical fibers faces economical obstacles. A promising option to address this issue is that of the most recent satellite systems, capable of providing high capacities virtually everywhere. However, compared to most terrestrial systems, satellite networks have very different link and, more importantly, latency characteristics, which often render them only barely usable for delay intolerant traffic. Thus, convergence of terrestrial and satellite networks is required, so that only certain traffic flows can be offloaded onto a supplemental satellite connection. In this work, we propose a network architecture relying on modern Software Defined Network (SDN) concepts, which enable dynamic traffic offloading in a converged satellite and terrestrial network, in order to relieve the load in a narrowband terrestrial network. We show that with limited overhead, a traffic can be offloaded, leading to an increase in the user's Quality-of-Experience (QoE).

Wireless Mesh Networks (WMNs) are often seen as an affordable solution to bring Internet connectivity into rural and previously unconnected regions. To date, the main focus has been to provide access to classical services such as the WWW or email which requires the users to use a personal computer or a recent smart phone. In many developing regions, however, the prevailing end user device is a mobile phone. In order to connect mobile phones to IP-based wireless back-haul networks, the network access points must provide a mobile phone air interface, compatible with GSM or UMTS specifications. Avoiding dependence on a costly mobile operator infrastructure, we propose to deploy GSM or 3GPP nano cells in order to terminate the mobile phone protocols immediately at the local network access points. Therefore, voice or data traffic can be carried over wireless back-haul networks using open protocols such as SIP and RTP. In this paper we present a meshed wireless back-haul network architecture whose access points have been equipped with GSM nano-cells. The voice packets generated by mobile phones are carried across the backhaul network in parallel to typical web or video traffic. We evaluate the QoS handling received by the voice calls across our multi-hop wireless testbed and show that our architecture can provide the resource isolation required to offer uninterrupted VoIP services in parallel to regular Internet traffic.