Handoff method and apparatus for terminal based on efficient set management in communication system
First Claim
1. A handoff method for a terminal in an idle state in a mobile communication system, the handoff method comprising:
- searching for a pilot of a single base station of an active set and a pilot of at least one base station of a neighbor set;
determining if, among the at least one base station of the neighbor set, there is a base station having pilot energy that is greater than that of the active set;
if there is the base station having the pilot energy that is greater than that of the active set in the neighbor set, determining if a pseudo noise offset of the base station of the neighbor set is equal to that of a base station included in an active set list including previous base stations that have been active sets;
if the pseudo noise offsets are equal, calculating a difference between a last time at which a previous base station functions as an active set prior to a current active set and a current time; and
if the difference is greater than a threshold time, determining if a pilot energy of the active set is less than a threshold and performing a handoff to the base station of the neighbor set.
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Accused Products
Abstract
A handoff method and apparatus for a terminal based on efficient set management. A pilot search rate for base stations of a neighbor set is increased, thereby preventing a failure to perform a necessary idle handoff or a failure to receive a paging message for a call connection. A terminal checks if it is in an idle state or in a traffic state, and measures the pilot energy of the BS of the active set and the pilot energy of a BS of the neighbor set with different pilot measurement patterns according to the checked state. The terminal measures the pilot of the BS of the active set and the pilots of at least one BS of the neighbor set while in the idle state. The terminal in the idle state operates in a sleep mode upon reception of information indicating that there is no paging channel, thereby minimizing its power consumption.
9 Citations
29 Claims
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1. A handoff method for a terminal in an idle state in a mobile communication system, the handoff method comprising:
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searching for a pilot of a single base station of an active set and a pilot of at least one base station of a neighbor set; determining if, among the at least one base station of the neighbor set, there is a base station having pilot energy that is greater than that of the active set; if there is the base station having the pilot energy that is greater than that of the active set in the neighbor set, determining if a pseudo noise offset of the base station of the neighbor set is equal to that of a base station included in an active set list including previous base stations that have been active sets; if the pseudo noise offsets are equal, calculating a difference between a last time at which a previous base station functions as an active set prior to a current active set and a current time; and if the difference is greater than a threshold time, determining if a pilot energy of the active set is less than a threshold and performing a handoff to the base station of the neighbor set. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A handoff method for a terminal, comprising:
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determining if a channel assignment message is received from a base station to check a connection state; and measuring a pilot energy of a single base station of an active set and pilot energies of a plurality of base stations of a neighbor set that are each distinct from the single base station of the active set using a first pilot measurement pattern by measuring the pilot energy of the plurality of base stations of the neighbor set at a same search rate as that of the active set when the connection state is a traffic state, and a second pilot measurement pattern by measuring the pilot energy of the single base station of the active set and pilot energies of at least three base stations of the neighbor set at a greater search rate than that of the active set when the connection state is an idle state. - View Dependent Claims (8, 9)
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10. A terminal that performs a handoff in a mobile communication system, the terminal comprising:
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a pilot energy extractor for measuring energy of a received pilot channel; a storing unit for storing the measured pilot energy separately for an active set and a neighbor set; a comparator for reading pilot energies of the active set and the neighbor set from the storing unit and comparing the read pilot energies using a first pilot measurement pattern by measuring the pilot energy of the plurality of base stations of the neighbor set at a same search rate as that of the active set when a connection state is a traffic state, and a second pilot measurement pattern by measuring the pilot energy of the single base station of the active set and pilot energies of at least three base stations of the neighbor set at a greater search rate than that of the active set when the connection state is an idle state; and a handoff unit for determining whether to perform a handoff according to a comparison result. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus that performs a handoff in a mobile communication system, the apparatus comprising:
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means for determining if a channel assignment message is received from a base station to check a connection state; and means for measuring a pilot energy of a single base station of an active set and a pilot energy of at least one base station of a neighbor set using a first pilot measurement pattern by means for measuring the pilot energy of a plurality of base stations of the neighbor set at a same search rate as that of the active set when the connection state is a traffic state, and a second pilot measurement pattern by means for measuring the pilot energy of the single base station of the active set and pilot energies of at least three base stations of the neighbor set at a greater search rate than that of the active set when the connection is an idle state. - View Dependent Claims (20, 21, 22)
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23. A non-transitory machine readable medium embodying instructions that, when executed by a processor, allow the processor to perform a handoff method
in a mobile communication system, the method comprising: -
measuring energy of a received pilot channel; storing the measured pilot energy separately for an active set and a neighbor set; reading pilot energies of the active set and the neighbor set and comparing the read pilot energies using a first pilot measurement pattern by measuring the pilot energy of a plurality of base stations of the neighbor set at a same search rate as that of the active set when the connection state is a traffic state, and a second pilot measurement pattern by measuring the pilot energy of the single base station of the active set and pilot energies of at least three base stations of the neighbor set at a greater search rate than that of the active set when the connection state is an idle state; and determining whether to perform a handoff according to the comparison result. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification