METHOD OF OPTIMIZING NEIGHBOR SET DURING SOFT HANDOFF OF A MOBILE UNIT IN A CDMA CELLULAR ENVIRONMENT

摘要

System and method for optimally updating a neighbor set for use by amobile unit during soft handoff of the mobile unit in a CDMA cellulartelephone environment is disclosed. A two-step process is used to ensure thatthe individual neighbor sets of active set members are combined in a mannersuch that only pilots representing the more important sectors are included inthe updated neighbor set and pilots representing the less important sectors areexcluded therefrom. In the first step, active set members whose RTD is morethan twice as great as an OWD threshold are eliminated from consideration.In the second step, the neighbor set of the mobile unit is updated using thesectors included in the individual neighbor sets of the active set members thatwere not excluded by the first step, wherein those sectors are included in theupdated neighbor set according to the number of individual sets in which theyare found and their priority within those sets. In an alternative embodiment, acombined carrier-to-interference ratio for each of the individual neighbor setmembers is also used in updating the neighbor set. In an alternativeembodiment, the individual neighbor set of the active set member having theshortest RTD is used as the updated neighbor set.