Assignment and reassignment schemes for OVSF codes in WCDMA
Proceedings of the 2006 international conference on Wireless communications and mobile computing
Multiple OVSF codes assignment with crowded branch first strategy in WCDMA systems
ICCOM'07 Proceedings of the 11th Conference on 11th WSEAS International Conference on Communications - Volume 11
OVSF code assignment strategies with minimal fragmentations for WCDMA systems
Computer Networks: The International Journal of Computer and Telecommunications Networking
Efficient integration OVSF code management strategies in UMTS
Computer Communications
OVSF Code Sharing and Reducing the Code Wastage Capacity in WCDMA
Wireless Personal Communications: An International Journal
IEEE Transactions on Wireless Communications
An efficient multi code design for code blocking reduction in 3G wireless networks
Sarnoff'10 Proceedings of the 33rd IEEE conference on Sarnoff
Efficient OVSF code assignment strategy in UMTS with multiple codes
ACOS'06 Proceedings of the 5th WSEAS international conference on Applied computer science
Reducing wastage capacity in OVSF based CDMA networks using dynamic rake combiners
WSEAS TRANSACTIONS on COMMUNICATIONS
Code scattering and reduction in OVSF code blocking for 3G and beyond mobile communication systems
WSEAS TRANSACTIONS on COMMUNICATIONS
Fair Single Code and Multi Code Designs for 3G and Beyond CDMA Systems
Wireless Personal Communications: An International Journal
Top Down Code Search to Locate An Optimum Code and Reduction in Code Blocking for CDMA Networks
Wireless Personal Communications: An International Journal
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In the third-generation partnership project technical specification, orthogonal variable spreading factor (OVSF) codes are used as channelization codes. The use of OVSF codes can provide variable data rates to flexibly support applications with different bandwidth requirements. Most works in the literature assume that only one single OVSF code is used to support one connection. This may sometimes waste the scarce wireless bandwidth since the allocated bandwidth will increase exponentially as the spreading factor decreases, i.e., a user may be "overserved." In this paper, we consider the possibility of using multiple OVSF codes to support a connection. We show how using multiple codes can reduce the internal and external fragmentations of an OVSF code tree. The tradeoff between bandwidth utilization and hardware complexity of a multicode system is analyzed. The result shows that using two or three codes will be quite cost effective. Several multicode assignment and reassignment strategies, namely, random, leftmost, crowded-first-space, and crowded-first-code, are proposed based on such an environment. Our simulation results show significant increase in code tree utilization and significant reduction in code blocking probability by using the crowded-first-space and crowded-first-code schemes.