Modern operating systems
Wireless Communications: Principles and Practice
Wireless Communications: Principles and Practice
Wcdma for Umts
Wideband DS-CDMA for next-generation mobile communications systems
IEEE Communications Magazine
UMTS/IMT-2000 based on wideband CDMA
IEEE Communications Magazine
Dynamic assignment of orthogonal variable-spreading-factor codes in W-CDMA
IEEE Journal on Selected Areas in Communications
IEEE Journal on Selected Areas in Communications
MSWIM '03 Proceedings of the 6th ACM international workshop on Modeling analysis and simulation of wireless and mobile systems
Efficient OVSF Codes Assignment Strategy and Management Architecture in Wideband CDMA
BROADNETS '04 Proceedings of the First International Conference on Broadband Networks
IEEE Transactions on Mobile Computing
Design and Analysis of Time-Based Code Allocation Schemes in W-CDMA Systems
IEEE Transactions on Mobile Computing
Joint Reliability of Medium Access Control and Radio Link Protocol in 3G CDMA Systems
IEEE Transactions on Computers
Wireless Personal Communications: An International Journal
Code Placement and Replacement Schemes for WCDMA Rotated-OVSF Code Tree Management
IEEE Transactions on Mobile Computing
Optimum OVSF code reassignment in wideband CDMA forward radio link
Information Sciences: an International Journal
Efficient OVSF Code Assignment and Reassignment Strategies in UMTS
IEEE Transactions on Mobile Computing
Assignment and reassignment schemes for OVSF codes in WCDMA
Proceedings of the 2006 international conference on Wireless communications and mobile computing
Non-blocking extended OVSF codes on multi-rate CDMA systems
Computer Communications
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
Handover provisioning in WCDMA systems
Proceedings of the 3rd international conference on Mobile multimedia communications
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
Genetic approach for dynamic OVSF code allocation in 3G wireless networks
Applied Soft Computing
Efficient OVSF code assignment and reassignment strategies in UMTS
Computer Communications
Optimum OVSF code reassignment in Wideband CDMA forward radio link
Information Sciences: an International Journal
MDP-based CAC for two-dimension spreading VSF-OFCDM in 4G cellular communications
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
EURASIP Journal on Wireless Communications and Networking
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
Graph model for optimal OVSF code placement strategies
International Journal of Ad Hoc and Ubiquitous Computing
An OVSF code assignment scheme utilizing multiple RAKE combiners for W-CDMA
Computer Communications
Stochastic methods for dynamic OVSF code assignment in 3G networks
SAGA'07 Proceedings of the 4th international conference on Stochastic Algorithms: foundations and applications
Stochastic optimization algorithm based dynamic resource assignment for 3G systems
NEW2AN'07 Proceedings of the 7th international conference on Next Generation Teletraffic and Wired/Wireless Advanced Networking
Fair Single Code and Multi Code Designs for 3G and Beyond CDMA Systems
Wireless Personal Communications: An International Journal
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The use of OVSF codes in WCDMA systems has offered opportunities to provide variable data rates to flexibly support applications with different bandwidth requirements. Two important issues in such an environment are the code placement problem and code replacement problem. The former may have significant impact on code utilization and, thus, code blocking probability, while the latter may affect the code reassignment cost if dynamic code assignment is to be conducted. The general objective is to make the OVSF code tree as compact as possible so as to support more new calls by incurring less blocking probability and less reassignment costs. Earlier studies about these two problems either do not consider the structure of the OVSF code tree or cannot utilize the OVSF codes efficiently. To reduce the call blocking probability and the code reassignment cost, we propose two simple yet efficient strategies that can be adopted by both code placement and code replacement: leftmost and crowded-first. Numerical analyses on call blocking probability and bandwidth utilization of OVSF code trees when code reassignment is supported are provided. Our simulation results show that the crowded-first strategy can significantly reduce, for example, the code blocking probability by 77 percent and the number of reassignments by 81 percent, as opposed to the random strategy when the system is 80 percent fully loaded and the max SF = 256.