Single code multiple access for the broadband satellite return channel

摘要

New broadband satellite access networks will provide user connectivity via a return channel from a centralized hub. The forward channel can be embedded into the broadcast channel yielding asymmetric bandwidth ratios of 10:1 or greater. To meet such a bandwidth asymmetry as well as the required quality of service, QoS, selection of multiple access and media access control protocol, plays a significant role among other design issues. In most of the recent satellite access networks, the forward traffic is broadcasted to the Satellite Interactive Terminals (SITs) using the ETSI specified DVB-S protocol. For the return channel multiple access protocol, options based on Multi-Frequency Time Division Multiple Access (MF-TDMA), Code Division Multiple Access (CDMA) and Random Multiple Access (RMA) are available. In this paper we present a comparative overview of connection- and contention-oriented multiple access and focus on the use of spread ALOHA by using one single long code.