Forward Link Performance of Combined Soft and Hard Handoff in Multimedia CDMA Systems

Sung Won KIM  Dong Geun JEONG  Wha Sook JEON  Chong-Ho CHOI  

IEICE TRANSACTIONS on Communications   Vol.E85-B   No.7   pp.1276-1282
Publication Date: 2002/07/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technology
CDMA,  forward link capacity,  combined soft and hard handoff,  multimedia service,  

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The soft handoff is widely adopted in code division multiple access (CDMA) systems for its many advantages mainly resulting from site diversity. However, in the forward link, other cell interference can be increased by soft handoff, decreasing system capacity. In future mobile systems, provision for the sufficient forward link capacity is very important since the forward link load is much higher than the reverse link load in mobile multimedia services such as Internet access. In this paper, we consider a combined handoff strategy in which voice services are provided with soft handoff whereas data services are supported with hard handoff. We analyze the effect of handoff method on the forward link performance. The performance measures we use are the outage probability of the bit energy to noise density ratio and the capacity based on the outage probability. As a result, we show that the combined handoff is very useful in CDMA cellular networks supporting both voice and data services simultaneously.