Reconstruction Methods of Tree Structure of Orthogonal Spreading Codes for DS-CDMA


IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E83-A   No.11   pp.2078-2084
Publication Date: 2000/11/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Spread Spectrum Techniques and Applications)
DS-CDMA,  orthogonal code,  spreading factor,  tree structure,  reconstruction,  

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In CDMA mobile system, network connection is constructed with orthogonal spreading codes assigned to each user in order to distinguish one from the other. The number of distinguishable codes and the process speed are different according to the orthogonal spreading factors which, in another literature, can be described as the tree structure. In this paper, we investigate methods to improve the quality of services (QoS) of communication, by changing the spreading factors of orthogonal spreading codes according to the number of users. We propose the effective method to reconstruct the tree structure of orthogonal spreading codes for supporting various data rates transmission in DS-CDMA mobile system. We compare spreading factors with and without the reconstruction and evaluate the effectiveness of the reconstruction method.