Quality of Service in Satellite Networks

摘要

Multimedia services are sensitive to delay, jitter and packet loss in different measures. The main requirements are timely data delivery, low delay, synchronisation, multicast, common protocols and communication guarantees. Networks usually meet these by overprovisioning, which is not a cost effective solution. To achieve network efficiency and QOS (Quality of Service), the network must provide error handling, synchronization of information, resource reservation and multicast. For wireless media, network must support link adaptive applications. Satellites can provide guaranteed multimedia services although with large delay, and high and variable BER (hit error rate) link. The advantages that the satellite medium offers are broadcast, simplified routing with single domain, constant delay and vast coverage. To provide satellite multimedia, all efforts are aimed at reducing processing, retransmission and double hop delays. This requires the development of specific algorithms for resource and power allocation etc. for the satellite link and also onboard processing. All layers of the protocol stack must be optimised for the satellite link in order to provide QoS. To do this, network topology and positioning of network entities must be defined. In this paper we address the issues involved in the provision of QoS for multimedia services over satellite.