Dhaka University Journal of Applied Science & Engineering

Broadband multimedia satellite system is the new generation communications satellite to meet an increasing demand for multimedia services and electronic connectivity across the world. In broadband satellite networks, TCP encounters serious problems especially for high data rates and high altitude satellites with longer delays. The satellite system based on LEO (Low Earth Orbit) or GEO (Geostationary Earth Orbit) constellations suffer from their intrinsic limitations in terms of converge or flexibility. Traffic management concerning broadband multimedia services is expected to be very uneven both in time and in space. To match the requirements, an innovative satellite system architecture is proposed that consists of LEO (Low Earth Orbit) and GEO (Geostationary Earth Orbit) satellite constellation. The paper describes the main features of TCP protocols over satellite link. To improve performance over satellite links, the paper proposed an algorithm that detects the congestion by considering the losses in two consecutive windows. The losses in the first window are most probably due to transmission error or others, but when such losses appear in the second window it considers the possibility of network congestion. The simulations are performed extensively with the NS2 satellite extension to evaluate the performance of the proposed algorithm. It is observed from the result that the proposed algorithm provides higher throughput than that of the SACK, which subsequently improves the effective throughput and reducing the total transmission time. In addition, the proposed algorithm efficiently manages slow-start problems and supports fairness among multiple connections.

1. ref1