High-Power Short Message Delivery Service via Multiple Non-GSO Satellites: Its Scheme and Scheduling Algorithm

Satoshi KONISHI  Megumi SHIBUYA  Shinichi NOMOTO  

IEICE TRANSACTIONS on Communications   Vol.E87-B   No.8   pp.2162-2172
Publication Date: 2004/08/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Fundamental Technologies for Broadband Satellite Communications)
non-GSO,  LEO/MEO,  SMS,  scheduling algorithm,  

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Electronic mail (email) is one of the most popular services using Internet Protocol (IP). Emails are now sent to and from portable phones in addition to laptop computers. The volume of emails is increasing because of the recent addition of attached electronic files. In addition, short message delivery services (SMS) that send email header information and the essence of email contents are also commonly used. Global short message delivery services via satellites are considered attractive for meeting the demand of increased short message delivery services. To establish a communications link for indoor subscribers, it is preferable to concentrate high transmission power into a spot-beam even using a non-geostationary satellite orbit (non-GSO) satellite system with low Earth orbits. The idea can be realized by a kind of TDMA scheme where only a single spot-beam per satellite is fired at a timeslot in an efficiently scheduled manner. This paper proposes a global short message delivery scheme and a scheduling algorithm that enables each satellite to concentrate its power into a spot-beam illuminating the addressed area in a prescribed timeslot, so that a subscriber in the area can efficiently receive a message addressed to the subscriber. Since the algorithm must guarantee that the spot-beam assignment causes no interference with other spot-beams from adjacent satellites, numerical evaluations are given for a 6-hour period MEO system, as an example, to demonstrate the efficacy and performance.