Packet reservation protocols for multichannel satellite networks

Abstract

Owing to system economics, many satellite data networks have star configurations, with low cost user terminals communicating with high performance hub earth stations over inbound multiaccess channels and outbound broadcast channels. The inbound channel data rate is often limited by the power budget, so that multiple satellite channels are required to accommodate the overall traffic in a large network. Most packet multiaccess protocols previously considered, when applied to multichannel satellite networks, enable distinct groups of users to share individual channels. In contrast, this paper presents a new class of multichannel reservation protocols (MRPs) which improves channel utilisation by enabling complete sharing of all channels among all users. For good throughput efficiency and reduced delay, the MRPs employ slotted random access with immediate retransmissions for first-packet and reservation request transmissions, and reservation of consecutive time slots for transmissions of remaining packets in multipacket messages. Delay throughput characteristics are derived under steady state conditions. Numerical results show that the MRPs achieve higher throughput capacity than random access protocols and lower average delay than other reservation protocols.