Method of optimizing neighbor set during soft handoff of a mobile unit in a CDMA cellular environment
First Claim
1. In a code division multiple access ("CDMA") cellular telephone system, a method of optimizing an updated neighbor set used by a mobile unit during soft handoff thereof, the method comprising the steps of:
- (a) determining a one-way-delay ("OWD") of each sector in an active set of said mobile unit;
(b) eliminating from consideration an individual neighbor set of any sector in said active set of said mobile unit having an OWD that is greater than a preselected OWD threshold, wherein said active set sectors having OWDs that are not greater than said preselected OWD threshold comprise acceptable active set sectors and individual neighbor sets associated with said acceptable active set sectors comprise acceptable neighbor sets; and
(c) forming an updated neighbor set for use by said mobile unit comprising neighbor sectors included in at least one of said acceptable neighbor sets.
5 Assignments
0 Petitions
Accused Products
Abstract
System and method for optimally updating a neighbor set for use by a mobile unit during soft handoff of the mobile unit in a CDMA cellular telephone environment is disclosed. A two-step process is used to ensure that the individual neighbor sets of active set members are combined in a manner such that only pilots representing the more important sectors are included in the updated neighbor set and pilots representing the less important sectors are excluded therefrom. In the first step, active set members whose RTD is more than 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 the sectors included in the individual neighbor sets of the active set members that were not excluded by the first step, wherein those sectors are included in the updated neighbor set according to the number of individual sets in which they are found and their priority within those sets. In an alternative embodiment, a combined carrier-to-interference ratio for each of the individual neighbor set members is also used in updating the neighbor set. In an alternative embodiment, the individual neighbor set of the active set member having the shortest RTD is used as the updated neighbor set.
115 Citations
31 Claims
-
1. In a code division multiple access ("CDMA") cellular telephone system, a method of optimizing an updated neighbor set used by a mobile unit during soft handoff thereof, the method comprising the steps of:
-
(a) determining a one-way-delay ("OWD") of each sector in an active set of said mobile unit; (b) eliminating from consideration an individual neighbor set of any sector in said active set of said mobile unit having an OWD that is greater than a preselected OWD threshold, wherein said active set sectors having OWDs that are not greater than said preselected OWD threshold comprise acceptable active set sectors and individual neighbor sets associated with said acceptable active set sectors comprise acceptable neighbor sets; and (c) forming an updated neighbor set for use by said mobile unit comprising neighbor sectors included in at least one of said acceptable neighbor sets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. In a code division multiple access ("CDMA") cellular telephone system, a method of optimizing an updated neighbor set used by a mobile unit during soft handoff thereof, the method comprising the steps of:
-
determining a one-way-delay ("OWD") for each sector with which said mobile unit is communicating, said sectors with which said mobile unit is communicating comprising a first active set; creating a second active set comprising all sectors of said first active set having an OWD that is within a preselected OWD threshold, each of said second active set sectors having associated therewith an individual neighbor set comprising a list of neighbor sectors, each of said neighbor sectors having a rank within said individual neighbor set; for each neighbor sector included in at least one of said individual neighbor sets; determining a number indicating in how many of said individual neighbor sets said neighbor sector is included; and calculating an updated rank for said neighbor sector from said ranks of said neighbor sector within said individual neighbor sets; and adding said neighbor sectors to said updated neighbor set in an order determined at least partially by said updated rank until said updated neighbor set is full. - View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. In a code division multiple access ("CDMA") cellular telephone system, a computer program for optimizing an updated neighbor set used by a mobile unit during soft handoff thereof, the computer program stored on at least one computer readable medium and comprising:
-
instructions for determining a one-way-delay ("OWD") for each sector with which said mobile unit is communicating, said sectors with which said mobile unit is communicating comprising a first active set; instructions for creating a second active set comprising all sectors of said first active set having an OWD that is within a preselected OWD threshold, each of said second active set sectors having associated therewith an individual neighbor set comprising a list of neighbor sectors, each of said neighbor sectors having a rank within said individual neighbor set; and instructions for forming an updated neighbor set for use by said mobile unit comprising at least one of said neighbor sectors. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
-
-
24. In a code division multiple access ("CDMA") cellular telephone system comprising a plurality of cells each divided into a plurality of sectors and served by a base station, said base stations establishing radio communications with a mobile unit for electrically connecting said mobile unit to a message switching center ("MSC") via a base station controller ("BSC"), apparatus for optimizing an updated neighbor set used by said mobile unit during soft handoff thereof, the apparatus comprising:
-
means for determining a one-way-delay ("OWD") for each sector with which said mobile unit is communicating, said sectors with which said mobile unit is communicating comprising a first active set; means for creating a second active set comprising all sectors of said first active set having an OWD that is within a preselected OWD threshold, each of said second active set sectors having associated therewith an individual neighbor set comprising a list of neighbor sectors, each of said neighbor sectors having a rank within said individual neighbor set; and means for forming an updated neighbor set for use by said mobile unit comprising at least one of said neighbor sectors. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31)
-
Specification