Broadband Satellite Networks

Abstract

A number of satellite communication systems have been proposed using geosynchronous (GEO) satellites, as well as low earth orbit (LEO) constellations operating in the Ka-band and above. At these frequencies satellite networks are able to provide broadband services requiring wider bandwidth than the current services at C or Ku-band. As a consequence, some of the new services gaining momentum include mobile services, private intranets and high data rate internet access carried over integrated satellite-fiber ATM networks. Several performance issues need to be addressed before a transport layer protocol, like TCP can satisfactorily work over satellite ATM for large delay-bandwidth networks. In this paper, we discuss some of the architectural options and challenges for broadband satellite ATM networks. The performance results of TCP enhancements for Unspecified Bit Rate over ATM (ATM-UBR+) for large bandwidth-delay environments with various end system policies and drop policies for GEO satellite configurations for several buffer sizes are presented.

Keywords: Broadband Satellite, ATM, UBR, TCP, Performance Analysis

1. Introduction

The rapid globalization of the telecommunications industry and the exponential growth of the Internet is placing severe demands on global telecommunications. Satisfying this demand is one of the greatest challenges before telecommunications industry in 21st century. Satellite communication networks can be an integral part of the newly emerging national and global information infrastructures (NII and GII).

Satellite communication offers a number of advantages over traditional terrestrial point-to-point networks. Satellite networks can cover wide geographic areas and can interconnect remote terrestrial networks ("islands"). In case of damaged terrestrial networks, satellite links provide an alternative. Satellites have a natural broadcast capability and thus facilitate multicast communication. Finally, satellite links can provide bandwidth on demand by using Demand Assignment Multiple Access (DAMA) techniques.

The growing congestion of the C and Ku bands