Design A New Time-Diversity System Using Orthogonal Mapping Matrix and Symbols Interleaving for Rayleigh Flat-Fading Channels
IEEE ACCESS • 2022
Publication Information
Authors
Ashraf Yahia Hassan; Ahmed Sami Mohammed
Keywords
Time diversity
,
flat fading channels
,
orthogonal mapping
,
maximum likelihood detector
,
linear detector
,
unity-gain-combiner
Journal
IEEE ACCESS
Publisher
IEEE
Volume
10
Issue
Not Available
Pages
29698-29715
publication.type
International
Paper Link
Open Link
Supplementary Materials
Not Available
Abstract
A time-diversity system is implemented in this work using a time-diversity encoder. The diversity encoder uses an orthogonal matrix to map vectors of N modulated symbols to vectors of N diversity symbols. Each modulated symbol is implicitly transmitted N times in N successive periods when the N diversity symbols are transmitted. No changes in the symbols’ transmission rate occur due to the proposed time-diversity scheme. The diversity symbols are transmitted with the same transmission rate of modulated symbols in the systems with no signal diversity. The proposed system uses the same bandwidth of the system with no signal diversity too. In the receiver, the outputs of the matched filter are stored in a buffer of length N during the diversity period. After filling the buffer, its contents are multiplied with the inverse of the fading matrix. A diversity detector remaps the diversity symbols to the modulated symbols. It also combines the corresponding modulated symbols in one decision variable. The noise samples in the decision variables are uncorrelated. A maximum-likelihood (ML) detector and a linear detector are used as diversity detectors in this work. The performance of the proposed system achieves the same performance as the N diversity channels system with a unity-gain-combiner (UGC) receiver.
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