IP Multicast via Satellite: A Survey

Many of the emerging applications in the Internet, such astele-conferencing, distance-learning, distributed games, softwareupdates, and distributed computing would benefit from multicastservices. In many of these applications, there is a need todistribute information to many sites that are widely dispersed fromeach other. Communication satellites are a natural technology optionand are extremely well suited for carrying such services. Despite thepotential of satellite multicast, there exists little support forsatellite IP multicast services. Both Internet Engineering andInternet Research Task Forces (IETF and IRTF) have been involved in aresearch effort to identify the design space for a general purposereliable multicast protocol and standardize certain protocolcomponents as emph{building blocks}. However, for satellitemulticast services, several of these components have a differentdesign space. In this paper, we attempt to provide an overview of thedesign space and the ways in which the network deployment andapplication requirements affect the solution space. We maintain asimilar taxonomy to that of the IETF efforts, and identify which keycomponents of a general multicast protocol are affected by two of themost common satellite network deployment scenarios. We also highlightsome of the issues which we think are critical in the development ofnext generation satellite IP multicast services

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

Packet Scheduling For Heterogeneous Multicast Transmissions

Multicast transmissions naturally raise the problem of the heterogeneity of receivers in terms of networking possibilities, host performances and user desires. Several solutions have been introduced but none suits all the situations. This paper describes a scheduling algorithm that unies some of these solutions, in particular in case of continuous data ows, and which is suited to a broad range of applications. An implementation of this algorithm is used to illustrate its behavior. 1 Introduction: The Needs Multicast transmissions naturally raise the problem of the heterogeneity of receivers. Several levels of heterogeneity can be identied: (1) the intrinsic performance of various parts of the network can be largely different; (2) the network performance can vary over the time because of congestion problems, of external factors (e.g. weather conditions in case of wireless communications), or a change of communication technology (e.g. switching from WaveLAN to GSM); (3) some privileg..