Selective soft handover calls drop for OVSF based CDMA networks

The base stations (BSs) are placed closed to each other in urban areas due to heavy data requirement of mobile networks which leads to frequent soft handover of calls due to movement of mobile stations (MSs) which leads to blocking of calls in different base stations (BSs) at same time due to orthogonal nature of orthogonal variable spreading factor (OVSF) codes in WCDMA networks. In this paper, a scheme is proposed which gives preference to a new call over soft handover calls. Soft handover call(s) are dropped to handle a new call(s). The motion of mobile stations (MSs) maybe random in a cell which leads to increase and decrease of received power at MS from BS. The received power of MSs is compared to select the soft handover call to be dropped. Simulations and results shows improvement in terms of code blocking probability.

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

[2]  Davinder S. Saini,et al.  Vacant codes grouping and fast OVSF code assignment scheme for WCDMA networks , 2013, Telecommun. Syst..

[3]  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).

[4]  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).

[5]  B. Gudmundson.  UMTS/IMT2000 based on wideband CDMA , 1998, ICCT'98. 1998 International Conference on Communication Technology. Proceedings (IEEE Cat. No.98EX243).

[6]  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.

[7]  Erik Dahlman,et al.  UMTS/IMT-2000 based on wideband CDMA , 1998, IEEE Commun. Mag..

[8]  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).

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

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

[11]  Yoshikuni Onozato,et al.  Region division assignment of orthogonal variable-spreading-factor codes in W-CDMA , 2001, IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211).