On the design of optimal spreading sequences for CDMA systems
- 31 October 2003
- proceedings article
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- Vol. 2, 1434-1438
- https://doi.org/10.1109/acssc.2002.1197016
Abstract
In this paper we consider two different sequence sets Signatures corrstrircred from Welch bound equalig se- qirences hare been show to be optimal in tenns of sum capacig in sychroiious CDMA systems. Unfortunately, rhese codeboob are afunctiori of the number of active signatures and need to be reassigned as the number of ocrise iisers changes ro mairitain optimalir): We describe and aiwlce hvo subclasses of Welch bound equalir) se- qireinces~om a theoretical and practical viewpoint. We show rhat mat-imiim Welch bound equaliv sequences are eqrriangular and thus each actii'e interferer experiences the same ainoiinr of interference. We show rhar,code- books constnrcred by .concatenating rnulriple onhanor- mal basis come closer to the Welch.boirrid when not a// sigirarrrres are active. Disciissionr and illiisrrations for Both constructions are presented.Keywords
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