SUMMARYThis paper introduces architectures for next-generation high throughput satellite (HTS) systems comprising various satellite payload options, ground terminal advances, and scalable system-level software control and management techniques. It describes a model to estimate aggregate system capacity as a function of radio band, available spectrum, spot beams, waveforms, and payload capability, including antenna size, power, and digital/ analog connectivity across various links and availability objectives. This system model has been used to evaluate aggregate capacity of representative Ka-Band low earth orbit and geosynchronous orbit systems. A system implementation approach is described for next-generation HTS systems based on widely used Industry standards. Modulation and coding techniques are based on Digital Video Broadcasting -S2 extensions (DVB-S2X), which comprises spectrally efficient modulation schemes combined with low-rate codes. Several implementation technologies are analyzed related to configurable onboard payload and ground-based, software-defined resource control and management, key enablers of next-generation HTS systems. Basic architectural building blocks are introduced for design of end-to-end systems across low earth orbit, medium earth orbit, and geosynchronous orbit satellite constellations, with and without onboard processing and inter-satellite links, and including several efficient scenarios to achieve lossless handovers.

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Mega satellite constellations in low earth orbit (LEO) will provide complete global coverage; rapidly enhance overall capacity, even for unserved areas; and improve the quality of service (QoS) possible with lower signal propagation delays. Complemented by medium earth orbit (MEO) and geostationary earth orbit (GEO) satellites and terrestrial network components under a hybrid communications architecture, these constellations will enable universal 5G service across the world while supporting diverse 5G use cases. With an unobstructed line-of-sight visibility of approximately 3 min, a typical LEO satellite requires efficient user terminal (UT), satellite, gateway, and intersatellite link handovers. A comprehensive mobility design for mega-constellations involves cost-effective space and ground phased-array antennas for responsive and seamless tracking. An end-to-end multilayer protocol architecture spanning space and terrestrial technologies can be used to analyze and ensure QoS and mobility. A scalable routing and traffic engineering design based on software-defined networking adequately handles continuous variability in network topology, differentiated user demands, and traffic transport in both temporal and spatial dimensions. The spacebased networks involving mega-constellations will be better integrated with their terrestrial counterparts by fully leveraging the multilayer 5G framework, which is the foundational feature of our hybrid architecture.

The current IEEE 802.11 medium access control standard is being deployed in coffee shops, in airports and even across major cities. The terminals accessing these wi-fi access points do not belong to the same entity, as in corporate networks, but are usually individually owned and operated. Entities sharing these network resources have no incentive in following protocol rules other than to optimize their overall utility, usually a function of throughput and delay. In this thesis, we discuss shortfalls of the current IEEE 802.11 standard in environments where terminals are competing for a common bandwidth resource, and then we introduce a new MAC protocol designed with the above considerations. Thus the new Incentive Compatible MAC (ICMAC) protocol uses Vickrey auction to allocate time slots and is more suited for these open environments, without compromising the overall network performance.

Third and Fourth Generation (3G and 4G) terrestrial systems provide higher speed Internet Protocol multimedia services to end-users with differentiated QoS across applications. To facilitate this, terrestrial architectures are moving towards an end-to-end all-IP architecture that unifies all services, including Voice over IP bearer. In parallel, Mobile Satellite Systems (MSS) are being designed to complement and/or co-exist with terrestrial coverage depending on spectrum sharing rules and operator choice. The challenge for MSS designers is to address the different physical layer characteristics while maintaining interoperability and compatibility with terrestrial services and reuse 3G Partnership Project core networks.To this end, MSS have been developed that mirror terrestrial Second Generation, 2.5G and 3G systems and are already operational in different parts of the world using different orbital constellations from low Earth orbits to geostationary orbits and both proprietary and standardized air interfaces. This paper describes architectures and methods for mobile satellite systems to achieve services similar to 3G and Fourth Generation terrestrial systems, focusing on the European Telecommunications Standards Institute Geostationary-Mobile Radio GMR-1 3G satellite air interface standard. now an approved standard in European Telecommunications Standards Institute and International Telecommunication Union [4,8] and is expected to be extensible to Release 12 3GPP specifications.These systems provide IP data services with data rates up to 590 kbps. Consistent with 3G/Fourth Generation (4G) specifications, the system provides differentiated QoS both across users and applications. In this framework, a given user terminal (UT) can invoke multiple applications simultaneously, each receiving their appropriate QoS treatment. The system permits both user mobility and terminal mobility across spot-beams within the satellite system as well as between satellite system and terrestrial systems using 3GPP standard signaling for intra-Radio Access Technology and inter-Radio Access Technology handovers. The terrestrial 3G standard was enhanced to achieve better spectral efficiency and improved throughput for satellite operation that is characterized by long delays, spectral scarcity, and limited link margins. Enhancements were primarily in the radio specific layers, namely physical layer, Media Access Control/Radio Link Control (MAC/RLC) layer and Packet Data Convergence Protocol (PDCP) layer, to achieve the necessary spectral efficiency and throughput improvement. The system leverages 3GPP IP Multimedia Subsystem-based services, including Voice over IP (VoIP) with circuit-switched spectral efficiency, resource efficient multicast, IP data with delay-optimized Bandwidth on Demand, dynamic link adaptation, Link Layer Automatic Repeat-reQuest, multiple levels of QoS, Transmission Control Protocol (TCP) Performance Enhancing Proxy (PEP), policy-based resource management, load balancing and position-based admission control, billin...