Future 5G mobile communication systems are expected to integrate different radio access technologies including the satellite component. Within the 5G framework, the terrestrial services can be augmented with the development of High Throughput Satellite (HTS) systems and new mega constellations meeting 5G requirements, such as high bandwidth, low latency, increased coverage, including rural areas, air, and seas. This paper provides an overview of the current 5G initiatives and projects followed by a proposed architecture for 5G satellite networks where the SDN/NFV approach facilitates the integration with the 5G terrestrial system. In addition, a novel technique based on network coding is analyzed for the joint exploitation of multiple paths in such integrated satelliteterrestrial system. For TCP-based applications, an analytical model is presented to achieve an optimal traffic split between terrestrial and satellite paths and optimal redundancy levels.

Satellite systems represent a significant solution to provide communication services to mobile users in under-populated regions, in emergency areas, on planes, trains, and ships. In all these cases, satellite systems have unique capabilities in terms of robustness, wide area coverage, and broadcast/multicast capabilities. This paper surveys current mobile satellite networks and services from different standpoints, encompassing research issues, recent standardization advances (e.g. mobile extension for DVB-S2/-RCS, DVB-SH) and some operational systems (e.g. Globalstar, Inmarsat BGAN, Iridium, and Thuraya). The last part of this paper is devoted to qualitative and quantitative comparisons of the different mobile satellite systems to understand their characteristics in terms of services, capacity, resource utilization efficiency, and user mobility degree

Abstract-It is anticipated that the satellite component of the future universal mobile telecommunications system (UMTS) will be based (partly or totally) on non-GEOstationary (non-GEO) constellations of satellites to serve mixed populations of users, each category being treated through different contracts stipulating different quality of service (QoS). In particular, we envisage a high-quality premium service which guarantees the success of each handover procedure, called guaranteed handover (GH) service, and a low-cost lower quality service called regular service, where handover failures are accepted provided that the probability of a call being unsuccessful does not exceed a given value. This paper proposes a strategy which eliminates forced call terminations due to handover failures, thus allowing the GH service. This procedure applies to low earth orbit (LEO) constellations using the satellite-fixed cell technique. An analytical model has been derived to calculate QoS parameters for a mixed population of GH and regular users. Providing both GH service to some users and regular service to other users requires an increased satellite capacity with respect to the case where all the users are served with the regular service; this capacity increase has been evaluated as a function of the percentage of GH users, the traffic load per cell, and the considered satellite mobility environment. The GH approach has been validated through the comparison with another scheme which envisages the queuing of handover requests for privileged users.

Abstract-Efficient dynamic channel allocation techniques with handover queuing suitable for applications in mobile satellite cellular networks, are discussed. The channel assignment on demand is performed on the basis of the evaluation of a suitable cost function. Geostationary and low earth orbit (LEO) satellites have been considered. In order to highlight the better performance of the dynamic techniques proposed, a performance comparison with a classical fixed channel allocation (FCA) has been carried out, as regards the probability that a newly arriving call is not completely served. It has also been shown that a higher traffic density, with respect to GEO systems, is manageable by means of LEO satellites.

This paper deals with an efficient Dynamic Channel Allocation (DCA) technique applicable to terrestrial mobile cellular networks. A channel (or resource) is a fixed frequency bandwidth (FDMA), a specific time-slot within a frame (TDMA), or a particular code (CDMA), depending on the multiple access technique used. A cost function has been defined by which the optimum channel to be assigned on demand can be selected. In addition, a suitable mobility model has been derived to determine the effects of handovers on network performance. The performance of the proposed DCA technique has been derived by computer simulations in terms of call blocking and handover failure probabilities. Comparisons with the classical Fixed Channel Allocation (FCA) technique and other dynamic allocation algorithms recently proposed in the literature have been carried out to validate the proposed technique