Online OVSF Code Assignment with Resource Augmentation

Abstract. Orthogonal Variable Spreading Factor (OVSF) code assignment is a fundamental problem in Wideband Code-Division MultipleAccess (W-CDMA) systems, which play an important role in third generation mobile communications. In the OVSF problem, codes must be assigned to incoming code requests, with different data rate requirements, in such a way that they are mutually orthogonal with respect to an OVSF code tree. An OVSF code tree is a complete binary tree in which each node represents a code associated with the combined bandwidths of its two children. To be mutually orthogonal, each leaf-to-root path must contain at most one assigned code. In this paper, we focus on the online version of the OVSF code assignment problem, in the oftenstudied context of the single cell as well as in the more general context of the whole multi-cell cellular network (for which there are no known results). With the help of 1/8 and 11/8 extra bandwidth resources, we are able to give a 5-competitive algori...

• Type: Conference
• Year: 2007
• Where: AAIM
• Authors: Francis Y. L. Chin, Yong Zhang, Hong Zhu
• Keywords: AAIM 2007, Algorithms, Code Assignment, OVSF Code, OVSF Code Tree