Interactive web service via satellite to the home

The satellite distribution of digital broadcast signals to the home has bec ome widespread in the last seven years, delivering hundreds of television c hannels. More recently we have seen other services appear, such as Direct P C(TM) where data is broadcast. This service may be used to deliver informat ion like stock quotes to a large number of users. or information such as We b pages may be requested by a single user. In the latter case, however, a r eturn path is needed from the end user to the service provider in order to provide the specific information requested by the user. In services offered today this information is usually provided by a terrestrial return link. m ost often a telephone line. While a telephone line with a modem is adequate in most cases, it has the drawback of tying up an existing telephone line for a considerable amount of time for very little data transmission, or req uiring an additional line. Furthermore. in many parts of the world a teleph one line may not be readily available. In these cases a satellite return li nk may be a viable option using VSATs. In this article we describe an inves tigation and simulation of a return path VSAT link designed specifically fo r delivery of Web traffic requests to a base station and thence via a terre strial link. using the Internet, to a Web server. The focus in this work is on the MAC protocol to support such a satellite channel and on modeling th e whole service from traffic generation through transport, network, and MAC layers to the physical channel.