Ali, Falah Hussain (1992) Collaborative coding multiple access communications. PhD thesis, University of Warwick.

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Abstract

This thesis investigates collaborative coding multiple access (CCMA) channel communication schemes. The CCMA schemes potentially permit efficient simultaneous transmission by several users sharing a common channel, without subdivision in time, frequency or orthogonal codes. The main areas of investigation include the information transmission capacity for single and multiple access channels, coding/decoding techniques and practical system design for CCMA schemes.

The information transmission capacity of a sampled and quantised single access AWGN channel is developed. It is determined and optimised when the channel input and output are limited by certain practical constraints. These investigations have led to the development and determination of the information transmission capacity of multiple access channels. The capacity of a multiple access channel is studied for two different classes of T-user channel models from both theoretical and practical points of view. It is shown, in principle, that higher transmission rates or, equivalently, more reliable communication than with time sharing is achievable employing the same signalling alphabet.

The CCMA schemes, in addition to providing the multiple access function, can also incorporate a certain degree of error control capability. Two main decoding techniques, hard decision and maximum likelihood soft decision, are presented with uniquely decodable CCMA schemes. A new low complexity maximum likelihood decoding technique is described and analysed. Reliability performance of various collaborative codes is studied by simulation employing these decoding techniques. It is shown that uniquely decodable schemes permit the multiple access function to be combined with forward error correction. It is also found that soft decision decoding can provide an energy gain over hard decision decoding.

The final area of investigation is a practical CCMA modem system design to combine collaborative coding and modulation. An M-ary frequency shift keying based modulation scheme is described for the T-user CCMA schemes. Three particular types of demodulation techniques, square-law, zerocrossing counting, and quadrature receiver, are described. These techniques are developed in software, tested and evaluated over noiseless and noisy channels.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Telecommunication systems, Code division multiple access, Spread spectrum communications, Coding theory, Multiple access protocols (Computer network protocols)
Official Date:	June 1992
Dates:	Date Event June 1992 Submitted
Institution:	University of Warwick
Theses Department:	Department of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Honary, Bahram
Format of File:	pdf
Extent:	xix, 213 leaves : illustrations, charts
Language:	eng

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