Proceedings ArticleDOI
Performance of orthogonal CDMA codes for quasi-synchronous communication systems
V.M. DaSilva,Elvino S. Sousa +1 more
- Vol. 2, pp 995-999
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TLDR
Orthogonal sequences based on the Sylvester-type Hadamard matrices (Walsh functions) are shown to provide a large improvement over the case where an orthogonal set is chosen at random.Abstract:
In this paper, the performance of quasi-synchronous direct-sequence CDMA communication systems based on different sets of orthogonal codes is investigated. The authors search for sets of sequences that minimize the probability of bit detection error, given that there is imperfect synchronization among the signals. Orthogonal sequences based on the Sylvester-type Hadamard matrices (Walsh functions) are shown to provide a large improvement over the case where an orthogonal set is chosen at random. For these sequences closed form expressions are derived for the average bit error rate. Computer searches indicate that this set of codes has special properties with respect to minimizing the average cross-correlations between the different signals for small errors in chip synchronization. It appears that these codes are optimal. A multi-carrier signalling scheme designed to help synchronize the CDMA signals at the chip level is also discussed.read more
Citations
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References
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Book
The Theory of Error-Correcting Codes
TL;DR: This book presents an introduction to BCH Codes and Finite Fields, and methods for Combining Codes, and discusses self-dual Codes and Invariant Theory, as well as nonlinear Codes, Hadamard Matrices, Designs and the Golay Code.
Journal ArticleDOI
On the capacity of a cellular CDMA system
Klein S. Gilhousen,Irwin M. Jacobs,Roberto Padovani,Andrew J. Viterbi,L.A. Weaver,Charles E. Iii Del Mar Wheatley +5 more
TL;DR: In this paper, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques.
Proceedings Article
On the capacity of a cellular CDMA system
Klein S. Gilhousen,Irwin M. Jacobs,Roberto Padovani,Andrew J. Viterbi,L.A. Weaver,Charles E. Iii Del Mar Wheatley +5 more
TL;DR: It is concluded that properly augmented and power-controlled multiple-cell CDMA (code division multiple access) promises a quantum increase in current cellular capacity.
Journal ArticleDOI
Performance Evaluation for Phase-Coded Spread-Spectrum Multiple-Access Communication--Part I: System Analysis
TL;DR: An analysis of an asynchronous phase-coded spread-spectrum multiple-access communication system reveals which code parameters have the greatest impact on communication performance and provides analytical tools for use in preliminary system design.
Journal ArticleDOI
Multistage detection in asynchronous code-division multiple-access communications
TL;DR: A multiuser detection strategy for coherent demodulation in an asynchronous code-division multiple-access system is proposed and analyzed, showing that the two-stage receiver is particularly well suited for near-far situations, approaching performance of single-user communications as the interfering signals become stronger.