Worldwide activities in mobile satellite communications fields.
نویسندگان
چکیده
منابع مشابه
Antenna System for Land Mobile Satellite Communications
Personal wireless communications is a true success story and has become part of people’s everyday lives around the world. Whereas in the early days of mobile communications Quality of Service (QoS) was often poor, nowadays it is assumed the service will be ubiquitous, of high speech quality and the ability to watch and share streaming video or even broadcast television programs for example is d...
متن کاملCompressed Video Applications Through Mobile Satellite Communications
The National Aeronautics and Space Administration (NASA) has been involved in the development of an experimental K(20 GHz) and Ka-band (30 GHz) satellite known as the Advanced Communications Technology Satellite (ACTS). The Jet Propulsion Laboratory (JPL) has been commissioned to develop two different mobile satellite communication (satcom) terminals to operate with ACTS. The first terminal, wh...
متن کاملEnhanced HARQ for Delay Tolerant Services in Mobile Satellite Communications
The objective of our paper is to improve efficiency (in terms of throughput or system capacity) for mobile satellite communications. In this context, we propose an enhanced Hybrid Automatic Repeat reQuest (HARQ) for delay tolerant services. Our proposal uses the estimation of the mutual information. We evaluate the performance of the proposed method for a land mobile satellite channel by means ...
متن کامل11.1 Doppler Measurement and Compensation in Mobile Satellite Communications Systems
The frequency errors dominated by the dynamic Doppler is analyzed for mobile satellite communication systems employing fast-moving satellites. Methods are proposed and analyzed for the basestations to measure and compensate the dynamic Doppler of large range. It is shown that the proposed methods give the minimum uncertainty of the dynamic Doppler for the modem to handle. Therefore, these metho...
متن کاملFrequency synchronization in global mobile satellite communications systems
Consider the frequency synchronization in global niobile satellite coiiiniunications systems. Let fc ( n , %: t ) be the t,raiismitt,ed ca.rrier frequency from the SAN t o the i-th user in the n-th spot bea.m, D c ( t ) be the fractional Doppler of t.he feeder link, fc6 be t,he translation frequency at. t.he sat.ellit,e, J f ( t ) be the fractional satel1it.e translation error, atid D,(n , i , ...
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ژورنال
عنوان ژورنال: The Journal of the Institute of Television Engineers of Japan
سال: 1989
ISSN: 0386-6831,1884-9652
DOI: 10.3169/itej1978.43.919