Multicast-aware Power Allocation in Multiple Spot-Beam Satellite Communication Systems

We address the problem of optimizing resource sharing and flow control in a multiple spot-beam broadband satellite system that supports both unicast and multicast flows. Satellite communication systems, with their wide-area coverage and direct access to large number of users, clearly have an inherent advantage in supporting multicast applications. In order to remain competitive against other broadband technologies, however, next generation satellite systems will be required to support both unicast and multicast flows and offer optimal sharing of system resources between these flows. We show that, in a multiple spot-beam system, a high load variation across spot-beam queues may force lower allocated session rates for active flows, and be perceived as unsatisfactory by potential users when both unicast and multicast flows are active in the system. We propose an optimization framework for balancing the spot-beam queue service rates such that the sum of the rate variances of all active multicast flows is minimized. This is achieved through the re-distribution of system power among spot-beam queues, by taking into account the load on the queues and the channel states. We conclude that it is possible to increase the average session rates of multicast flows by up to 16%, and the rates of unicast flows by up to 4% after this optimization is applied

IP multicast receiver mobility support using PMIPv6 in a global satellite network

YesA new generation of satellite systems that support regenerative on-board processors (OBPs) and multiple spot beam technology have opened new and efficient possibilities of implementing IP multicast communication over satellites. These new features have widened the scope of satellite-based applications and also enable satellite operators to efficiently utilize their allocated bandwidth resources. This makes it possible to provide cost effective satellite network services. IP multicast is a network layer protocol designed for group communication to save bandwidth resources and reduce processing overhead on the source side. The inherent broadcast nature of satellites, their global coverage (air, land, and sea), and direct access to a large number of subscribers imply satellites have unrivalled advantages in supporting IP multicast applications. IP mobility support in general and IP mobile multicast support in particular on mobile satellite terminals like the ones mounted on long haul flights, maritime vessels, continental trains, etc., still remain big challenges that have received very little attention from the research community. This paper proposes how Proxy Mobile IPv6 (PMIPv6)-based IP multicast mobility support defined for terrestrial networks can be adopted and used to support IP mobile multicast in future satellite networks, taking cognizance of the trend in the evolution of satellite communications

Applications of satellite technology to broadband ISDN networks

Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about $190M whereas the second architecture would be about$250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

Evolution of High Throughput Satellite Systems: Vision, Requirements, and Key Technologies

High throughput satellites (HTS), with their digital payload technology, are expected to play a key role as enablers of the upcoming 6G networks. HTS are mainly designed to provide higher data rates and capacities. Fueled by technological advancements including beamforming, advanced modulation techniques, reconfigurable phased array technologies, and electronically steerable antennas, HTS have emerged as a fundamental component for future network generation. This paper offers a comprehensive state-of-the-art of HTS systems, with a focus on standardization, patents, channel multiple access techniques, routing, load balancing, and the role of software-defined networking (SDN). In addition, we provide a vision for next-satellite systems that we named as extremely-HTS (EHTS) toward autonomous satellites supported by the main requirements and key technologies expected for these systems. The EHTS system will be designed such that it maximizes spectrum reuse and data rates, and flexibly steers the capacity to satisfy user demand. We introduce a novel architecture for future regenerative payloads while summarizing the challenges imposed by this architecture

Multicast communication support over satellite networks

In this dissertation, we focus on providing multicast communication support over satellite networks. We investigate the possible performance enhancements in terms of the throughput, capacity, and scalability of a Ka-band, multiple spot-beam satellite communication system that supports unicast and multicast services. The role satellite systems play in today's communication infrastructure is changing rapidly, fueled by the technological advance in the design of new satellite systems, and by the new multimedia service applications, such as on-demand multimedia content delivery, distance learning, and distributed software updates that would benefit from the wide-area coverage, direct and ubiquitous access capability of the satellite systems. These applications require concurrent transmission of the same content to multiple users. In order for multicasting-based services to grow over satellite networks, there must be an incentive to deploy them. We address the problem of user heterogeneity that occurs when multicast users that are located across several different spot-beam locations experience different channel conditions. We propose a novel power allocation scheme for smoothing out the heterogeneity experienced by the multicast groups, while making sure that unicast users get a fair share of system resources as well. Our power allocation scheme would benefit from user feedback in determining the channel conditions. However, collecting feedback from a large set of users is a challenging task in satellite systems, since access to the uplink bandwidth is to be shared between several users, and the resources are usually limited. We introduce a novel algorithm that reduces the volume of feedback information that is to be transmitted over the satellite segment of the network, while maintaining that the relevant information is collected in a timely manner. Finally, we focus our attention to the potential benefits of integrating packet level forward error correction coding to packet delivery for reliable multicast services over satellite networks. Forward error protection helps recover corrupted data, and minimizes the need for retransmissions over the satellite channel. We investigate the use of a special form of forward error correcting (FEC) code and couple it with an adaptive control mechanism to dynamically adjust the number of encoding packets forwarded to the users

Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed

Rate-splitting multiple access for non-terrestrial communication and sensing networks

Rate-splitting multiple access (RSMA) has emerged as a powerful and flexible non-orthogonal transmission, multiple access (MA) and interference management scheme for future wireless networks. This thesis is concerned with the application of RSMA to non-terrestrial communication and sensing networks. Various scenarios and algorithms are presented and evaluated. First, we investigate a novel multigroup/multibeam multicast beamforming strategy based on RSMA in both terrestrial multigroup multicast and multibeam satellite systems with imperfect channel state information at the transmitter (CSIT). The max-min fairness (MMF)-degree of freedom (DoF) of RSMA is derived and shown to provide gains compared with the conventional strategy. The MMF beamforming optimization problem is formulated and solved using the weighted minimum mean square error (WMMSE) algorithm. Physical layer design and link-level simulations are also investigated. RSMA is demonstrated to be very promising for multigroup multicast and multibeam satellite systems taking into account CSIT uncertainty and practical challenges in multibeam satellite systems. Next, we extend the scope of research from multibeam satellite systems to satellite- terrestrial integrated networks (STINs). Two RSMA-based STIN schemes are investigated, namely the coordinated scheme relying on CSI sharing and the co- operative scheme relying on CSI and data sharing. Joint beamforming algorithms are proposed based on the successive convex approximation (SCA) approach to optimize the beamforming to achieve MMF amongst all users. The effectiveness and robustness of the proposed RSMA schemes for STINs are demonstrated. Finally, we consider RSMA for a multi-antenna integrated sensing and communications (ISAC) system, which simultaneously serves multiple communication users and estimates the parameters of a moving target. Simulation results demonstrate that RSMA is beneficial to both terrestrial and multibeam satellite ISAC systems by evaluating the trade-off between communication MMF rate and sensing Cramer-Rao bound (CRB).Open Acces

Load balancing in multi-beam satellites

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201