Compressed mode techniques for inter-frequency measurements in a wide-band DS-CDMA system

We discuss inter-frequency hand-over (IFHO) in third generation cellular systems based on wide-band DS-CDMA. In order to provide maximum flexibility for future radio network design, it is important to develop a technique allowing reliable IFHO in the system. The compressed mode (CM) scheme first presented by Baier et. al (see IEEE JSAC, vol.12, no.4, p.733-43, 1994) facilitates the use of the mobile-assisted hand-over (MAHO) technique commonly used in all second generation systems, also for IFHO in a CDMA system. We present and analyze four different ways of achieving a CM mechanism in a CDMA system. It is found that methods based on a variable spreading factor and coding-rate increment may be of most interest for practical use.