naa a22 4500 51079873X CHVBK 20180411083346.0 cr unu---uuuuu 180411e20131001xx s 000 0 eng 10.1007/s11277-013-1144-6 doi (NATIONALLICENCE)springer-10.1007/s11277-013-1144-6 The Assignment of CDMA Spreading Codes Constructed from Hadamard Matrices and Almost Bent Functions [Elektronische Daten] [Francis Hunt, Derek Smith] Almost bent functions and Hadamard matrices can be used to construct spreading codes for code-division multiple-access (CDMA) systems. Four specific Hadamard matrices can be constructed and each one can be divided into eight octants in such a way that spreading codewords from certain pairs of octants have zero correlation. It is possible to assign these octants to a regular tessellation of hexagonal cells in such a way that there is zero correlation between adjacent cells, small correlation between non-adjacent cells and a large codeword re-use distance. If synchronous CDMA is used in a satellite system, interference is reduced in comparison with the use of a single Hadamard matrix. In this case the regular hexagonal tessellation is usually a good model of the areas covered by satellite spot beams. The same approach can be advantageous when the Hadamard matrices are used to construct loosely synchronized codes for a terrestrial system. The tessellation of cells is unlikely to be a regular hexagonal tessellation and the question arises of whether an assignment to an irregular tessellation with these properties can be found. In this paper a positive answer is given to this question, confirming that the approach is applicable to a terrestrial system. Springer Science+Business Media New York, 2013 Code-division multiple-access nationallicence Hadamard matrices nationallicence Code assignment nationallicence Hunt Francis Division of Mathematics and Statistics, University of Glamorgan, Pontypridd, CF37 1DL, Mid Glamorgan, Wales, UK aut Smith Derek Division of Mathematics and Statistics, University of Glamorgan, Pontypridd, CF37 1DL, Mid Glamorgan, Wales, UK aut Wireless Personal Communications Springer US; http://www.springer-ny.com 72/4(2013-10-01), 2215-2227 0929-6212 72:4<2215 2013 72 11277 https://doi.org/10.1007/s11277-013-1144-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11277-013-1144-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hunt Francis Division of Mathematics and Statistics, University of Glamorgan, Pontypridd, CF37 1DL, Mid Glamorgan, Wales, UK aut NATIONALLICENCE 700 1- Smith Derek Division of Mathematics and Statistics, University of Glamorgan, Pontypridd, CF37 1DL, Mid Glamorgan, Wales, UK aut NATIONALLICENCE 773 0- Wireless Personal Communications Springer US; http://www.springer-ny.com 72/4(2013-10-01), 2215-2227 0929-6212 72:4<2215 2013 72 11277 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer