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Title: Satellite multiple access protocols for land mobile terminals : a study of the multiple access environment for land mobile satellite terminals, including the design analysis and simulation of a suitable protocol and the evaluation of its performance in a U.K. system
Author: Fenech, Hector Tony
ISNI:       0000 0004 2707 0391
Awarding Body: University of Bradford
Current Institution: University of Bradford
Date of Award: 1987
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This thesis is a study of multiple access schemes for satellite land mobile systems that provide a domestic or regional service to a large number of small terminals. Three orbit options are studied, namely the geostationary, elliptical (Molniya) and inclined circular orbits. These are investigated for various mobile applications and the choice of the Molniya orbit is justified for a U. K. system. Frequency, Time and Code Division Multiple Access (FDMA, TDMA and CDMA) are studied and their relative merits in the mobile environment are highlighted. A hybrid TDMA/FDMA structure is suggested for a large system. Reservation ALOHA schemes are appraised in a TDMA environment and an adaptive reservation multiple access protocol is proposed and analysed for a wide range of mobile communication traffic profiles. The system can cope with short and long data messages as well as voice calls. Various protocol options are presented and a target system having 100,000 users is considered. Analyses are presented for the steady state of protocols employing pure and slotted ALOHA and for the stabilty of the slotted variant, while simulation techniques were employed to validate the steady state analysis of the slotted ALOHA protocol and to analyse the stability problem of the pure ALOHA version. An innovative technique is put forward to integrate the reservation and the acquisition processes. It employs the geographical spread of the users to form part of the random delay in P-ALOHA. Finally an economic feasibility study is performed for the spacesegment. For costs of capital (r) less than 23 % the discounted payback period is less than the project's lifetime (10 years). At r- 8% the payback period is about 5.6 years, while the internal-rate-of-return is 22.2 %. The net present value at the end of the projects lifetime is £M 70 at r-8%.
Supervisor: Watson, P. A. ; Gardiner, J. G. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Satellite multiple access protocols ; Land mobile terminals ; Multiple access environment ; Design and analysis ; Simulation ; Performance evaluation ; United Kingdom (UK) ; Geostationary orbit ; Elliptical orbit ; Inclined circular orbit