TIME SLOT ASSIGNMENT PROBLEM FOR SS/TDMA SYSTEM

Abstract

Networking via satellite is one of the most significant advances made in worldwide coramunioations. It becomes an attractive choice when a large number of distant users with fluctuating traffic require a fully interconnected network. A single geostationary satellite enables such vast traffic flow with the help of multj.. pie access techniques. Two most common multiple access techniques are FDMA and TE lA, TDMA is now being intro-duced extensively into geostationary satellite service because it achieves greater capacity compared to FDNA and permits traffic reassignment. The use of spot beams in TDMA enhances downlink EIRP by about 8 dB. Further TDMA uses multiple beams to achieve spectrum reuse., By introducing satellite switching as a companion to TDMA, fully routing connectivity among the beams of multiple beam satellite is achieved. A SS/TII4A system tsing a microwave switch matrix of redundant design shows an increase of over 30 percent in available capacity over FDMWTDMA. An important network control problem that occurs when a satellite switch is introduced into SS/ TDMA system lies in the selection of connection patterns between up-beams and down-beams needed to optimally accommodate the overall traffic flow of the system; These selection patterns (switch states) govern the connections of the satellite switch. Several algorithms have been suggested to optimize the traffic flow.