Optimum OVSF code reassignment in Wideband CDMA forward radio link

This paper focuses on minimizing the code reassignment cost in Wideband CDMA forward link. The channel allocation of wireless links can be transformed into the Orthogonal Variable Spreading Factor (OVSF) code assignment problem. Orthogonality constraint in the OVSF code tree may prevent efficient resource utilization. Code reassigning process can achieve an average of 20% gain of system throughput. Minimizing the code reassignments is essential in reducing the complexity of the wireless system. We present the design methodology and implementation techniques of the proposed efficient algorithm MIN in optimizing the reassignment cost. The simulation result indicates that the MIN algorithm can reduce in average 60% of the reassignment cost compared to that of the heuristic method and it is feasible for implementing in Base Station or Radio Network Controller.

[1]  Fen-Fen Shueh,et al.  A fair, efficient, and exchangeable channelization code assignment scheme for IMT-2000 , 2000, 2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488).

[2]  Kai-Yeung Siu,et al.  Dynamic assignment of orthogonal variable-spreading-factor codes in W-CDMA , 2000, IEEE Journal on Selected Areas in Communications.

[3]  Yu-Chee Tseng,et al.  Code placement and replacement strategies for wideband CDMA OVSF code tree management , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[4]  F. Shueh,et al.  Code assignment for IMT-2000 on forward radio link , 2001, IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202).

[5]  Kyung Sup Kwak,et al.  A hybrid multi-rate scheme for WCDMA , 1999, Proceedings of IEEE. IEEE Region 10 Conference. TENCON 99. 'Multimedia Technology for Asia-Pacific Information Infrastructure' (Cat. No.99CH37030).

[6]  Uwe-Carsten Fiebig,et al.  Design study for a CDMA-based third-generation mobile radio system , 1994, IEEE J. Sel. Areas Commun..

[7]  Fumiyuki Adachi,et al.  Tree-structured generation of orthogonal spreading codes with different lengths for forward link of DS-CDMA mobile radio , 1997 .

[8]  Fumio Watanabe,et al.  IMT-2000 standards: radio aspects , 1997, IEEE Wirel. Commun..

[9]  Mauro Dell'Amico,et al.  Efficient algorithms for the assignment of OVSF codes in wideband CDMA , 2002, 2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333).

[10]  Kai-Yeung Siu,et al.  Supporting rate guarantee and fair access for bursty data traffic in W-CDMA , 2001, IEEE J. Sel. Areas Commun..

[11]  Wen-Tsuen Chen,et al.  A novel code assignment scheme for W-CDMA systems , 2001, IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211).

[12]  I Chih-Lin,et al.  Multi-code CDMA wireless personal communications networks , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[13]  A. Viterbi.  CDMA: Principles of Spread Spectrum Communication , 1995 .

[14]  Ramjee Prasad,et al.  An overview of CDMA evolution toward wideband CDMA , 1998, IEEE Communications Surveys & Tutorials.

[15]  Phone Lin,et al.  OVSF code channel assignment for IMT-2000 , 2000, VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026).