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Enhancement of Channel Efficiency for CDMA Systems using New Soft Handoff Scheme

S. Tamilselvan, K. Manivannan


Code Division Multiple Access (CDMA) cellular system that provides seamless connectivity is featured by soft handoff, which is accompanied by power control, selection diversity and rake receiver. In IS-95/CDMA-2000 based handoff schemes or systems some handoff calls unnecessarily occupy multiple channels with little contribution to the performance of handoffs. It is noted that new calls are blocked due to the channel resource shortage. In order to efficiently utilize the channel resource those extra channels occupied by handoff calls are grouped into a set called channel convertible set (CCS) by considering the relative mobility of the call. A new scheme called Channel-Conversion with Dynamic Guard channel reservation (CCDG) that reallocates those extra channels in the CCS to new handoff calls when there is no available channel in the system is proposed. According to the variation of the CCS the scheme dynamically adjusts the number of guard channels reserved exclusively for handoff, which still enhances the system performance. It is noted that the proposed scheme can significantly decrease both the number of dropped handoff calls and the number of blocked calls without degrading the quality of communication service.


CDMA, power control, handoff, Guard channel

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Wong and T. J. Lim, 1997. “Soft handoff in CDMA mobile system,” IEEE Personal Communication, vol. 4, no. 6, pp. 6–17.

William C. Y. Lee, 1995. Mobile Cellular Telecommunications – Analog and Digital Systems, McGraw-Hill, Second Edition.

J. Lee and D. H. Cho, 2000. “Performance analysis of channel-borrowing handoff scheme based on user mobility in CDMA cellular systems” IEEE Transaction Vehicular Technology vol. 49, no.6, pp 2276-2285.

X. Ma, Y. Cao, Y. Liu and K.S. Trivedi, 2005. “Modeling and Performance analysis for mobility based soft handoff scheme in CDMA cellular system”, IEEE Transaction Vehicular Technology.

S. L. Su, J. Y. Chen, and J. H. Huang, 1996. “Performance analysis of soft handoff in CDMA cellular networks,” IEEE J. Sel. Areas Communication, vol. 14, no. 9, pp. 1762–1769.

Rosy Pillay Narrainen and Fambirai Takawira, 2001.“Performance analysis of soft handoff in CDMA cellular networks”, IEEE Transaction on Vehicular Technology, vol. 50, no. 6, pp. 1507-1517.

J. Viterbi, A. M. Viterbi, K. S. Gilhousen, and E. Zehavi, 1994. “Soft handoff extends CDMA cell Coverage and increases reverse link capacity,” IEEE J. Selected. Areas Communication, vol. 12, no. 8, pp. 1281–1288.

S. Das, W. M. MacDonald, and H. Viswanathan, “Sensitivity analysis of handoff algorithms in CDMA forward link,” IEEE Transaction on Vehicular Technology, vol. 54, no. 1, pp. 272-285, Jan 2005.

Sung, “Analysis of fade margins for soft and hard handoffs in cellular CDMA systems,” IEEE Transactions on Wireless Communications, vol. 2, no. 3, pp. 431-435, May 2003.

Lee and R. Steele, “Effect of soft and softer handoffs on CDMA system capacity,” IEEE Transaction on Vehicular Technology, vol. 47, no. 3, pp. 830–841, Aug. 1998.

M. Chopra, K. Rohani, and J. D. Reed, “Analysis of CDMA range extensions due to soft handoff,” in Proc. 1995 IEEE Vehicular Technology Conference, Chicago, IL, pp. 917–921, July 1995..

K. S. Gilhousen, I. M. Jacobs, R. Padovani, A. J. Viterbi, L. A. Weaver, and C. Wheatly, “On the capacity of a cellular CDMA system,” IEEE Trans. Veh. Technol., vol. 40, pp. 303–312, May 1991.

Kim and D. G. Jeong, “Capacity unbalance between uplink and downlink in spectrally overlaid narrow-band and wide-band CDMA mobile systems,” IEEE Transaction on Vehicular Technology, vol. 49, no. 4, pp. 1086–1093, Jul. 2000.


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