Composite CDMA—a statistical mechanics analysis

Raymond, Jack and Saad, David (2009). Composite CDMA—a statistical mechanics analysis. Journal of Statistical Mechanics, 2009 (5),

Abstract

Code division multiple access (CDMA) in which the spreading code assignment to users contains a random element has recently become a cornerstone of CDMA research. The random element in the construction is particularly attractive as it provides robustness and flexibility in utilizing multiaccess channels, whilst not making significant sacrifices in terms of transmission power. Random codes are generated from some ensemble; here we consider the possibility of combining two standard paradigms, sparsely and densely spread codes, in a single composite code ensemble. The composite code analysis includes a replica symmetric calculation of performance in the large system limit, and investigation of finite systems through a composite belief propagation algorithm. A variety of codes are examined with a focus on the high multi-access interference regime. We demonstrate scenarios both in the large size limit and for finite systems in which the composite code has typical performance exceeding those of sparse and dense codes at equivalent signal to noise ratio.

Publication DOI: https://doi.org/10.1088/1742-5468/2009/05/P05015
Divisions: Engineering & Applied Sciences
Engineering & Applied Sciences > Mathematics
Engineering & Applied Sciences > Systems analytics research institute (SARI)
Additional Information: © 2009 IOP Publishing Ltd and SISSA
Uncontrolled Keywords: random graphs,networks,disordered systems,source and channel coding
Full Text Link: http://iopscien ... 2009/05/P05015/
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2009-05-21
Authors: Raymond, Jack
Saad, David ( 0000-0001-9821-2623)

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