Multi code assignment with minimum number of rakes for OVSF CDMA

Orthogonal Variable Spreading Factor (OVSF) codes suffers from code blocking limitation, keeping the code tree as compact as possible merely depending on the request rate, we design a multi code scheme with and without reassignments which assigns call to a code with immediate busy neighbor or whose immediate neighbor maximum capacity is utilized. The paper proposes multi code schemes with reassignments require minimum rakes to handle a call and will lead to lesser fragmentation when a call. Simulation results are demonstrated to show the superiority of the proposed scheme as compared to other existing schemes as it uses minimum number of codes and fewer codes are searched to handle a new call.

[1]  Yu-Chee Tseng,et al.  Code Placement and Replacement Strategies for Wideband CDMA OVSF Code Tree Management , 2002, IEEE Trans. Mob. Comput..

[2]  Li-Hsing Yen,et al.  An OVSF code assignment scheme utilizing multiple RAKE combiners for W-CDMA , 2004, Comput. Commun..

[3]  Vipin Balyan,et al.  Immediate neighbor assignment and reduction in code blocking for OVSF-WCDMA , 2010, SoftCOM 2010, 18th International Conference on Software, Telecommunications and Computer Networks.

[4]  Chih-Min Chao,et al.  Reducing internal and external fragmentations of OVSF codes in WCDMA systems with multiple codes , 2005, IEEE Transactions on Wireless Communications.

[5]  Angelos N. Rouskas,et al.  OVSF codes assignment and reassignment at the forward link of W-CDMA 3G systems , 2002, The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications.

[6]  Ken'ichi Kawanishi,et al.  Hybrid OVSF code assignment scheme in W-CDMA , 2003, 2003 IEEE Pacific Rim Conference on Communications Computers and Signal Processing (PACRIM 2003) (Cat. No.03CH37490).

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

[8]  Yang Yang,et al.  Maximally flexible assignment of orthogonal variable spreading factor codes for multirate traffic , 2004, IEEE Transactions on Wireless Communications.

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

[10]  Davinder S. Saini,et al.  Adaptive assignment scheme for OVSF codes in WCDMA , 2006, 2006 International Conference on Wireless and Mobile Communications (ICWMC'06).

[11]  Vipin Balyan,et al.  Call elapsed time and reduction in code blocking for WCDMA networks , 2009, SoftCOM 2009 - 17th International Conference on Software, Telecommunications & Computer Networks.

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

[13]  Daniel C. Lee,et al.  Enhanced Fixed and Dynamic Code Assignment Policies for OVSF-CDMA Systems , 2003, International Conference on Wireless Networks.

[14]  Fumiyuki Adachi,et al.  Wideband DS-CDMA for next-generation mobile communications systems , 1998, IEEE Commun. Mag..

[15]  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).