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Adaptive data rate SSMA system for personal and mobile satellite communicationsAn adaptive data rate SSMA (spread spectrum multiple access) system is proposed for mobile and personal multimedia satellite communications without the aid of system control earth stations. This system has a constant occupied bandwidth and has variable data rates and processing gains to mitigate communication link impairments such as fading, rain attenuation and interference as well as to handle variable data rate on demand. Proof of concept hardware for 6MHz bandwidth transponder is developed, that uses offset-QPSK (quadrature phase shift keying) and MSK (minimum shift keying) for direct sequence spread spectrum modulation and handle data rates of 4k to 64kbps. The RS422 data interface, low rate voice and H.261 video codecs are installed. The receiver is designed with coherent matched filter technique to achieve fast code acquisition, AFC (automatic frequency control) and coherent detection with minimum hardware losses in a single matched filter circuit. This receiver structure facilitates variable data rate on demand during a call. This paper shows the outline of the proposed system and the performance of the prototype equipment.
Document ID
Document Type
Conference Paper
Ikegami, Tetsushi (Communications Research Lab. Kashima, Japan)
Takahashi, Takashi (Communications Research Lab. Kashima, Japan)
Arakaki, Yoshiya (Communications Research Lab. Kashima, Japan)
Wakana, Hiromitsu (Communications Research Lab. Kashima, Japan)
Date Acquired
August 17, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Proceedings of the Fourth International Mobile Satellite Conference (IMSC 1995)
Subject Category
Communications and Radar
Distribution Limits
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19960022452Analytic PrimaryProceedings of the Fourth International Mobile Satellite Conference (IMSC 1995)
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