Baseband Digital Signals, Packet Networks, and Quality of Service (QoS)

Summary

This chapter discusses the types of baseband signals associated with the considered service and its related quality. Baseband signals such as telephone signals, sound programmes, television, and data techniques are discussed. The chapter introduces the concept of Quality of Service (QOS) in terms of performance objectives, measured by bit error rate (BER) and availability objectives. Techniques for digital speech concentration such as digital speech interpolation take account of the activity factor of telephone channels in order to reduce the number of satellite channels required to transmit a given number of terrestrial telephone channels. For a geostationary satellite with no intersatellite link, the minimum and maximum values of the overall delay, often called the hop delay, is calculated. For packet networks, all the QoS and performance measurements are carried out for Internet Protocol (IP) packets at the IP network level.