Fuzzy logic control of cellular handoff
First Claim
1. A method of controlling handoff in a cellular radio communications system, comprising the steps of:
- monitoring parameters for use in determining handoffs;
in a handoff triggering step, applying fuzzy logic procedures to at least one monitored parameter to selectively determine a trigger for handoff of a mobile terminal from a serving base station, via which the mobile terminal is communicating, to another base station from among a plurality of adjacent base stations;
in a handoff targeting step separate from the handoff triggering step and responsive to the handoff trigger, applying fuzzy logic procedures to at least one monitored parameter to determine preferences for handoff of the mobile terminal to different ones of said plurality of adjacent base stations; and
executing handoff of the mobile terminal from the serving base station to one of said plurality of adjacent base stations in accordance with said preferences.
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Accused Products
Abstract
In a cellular radio communications system, handoff of a mobile terminal from a serving base station to an adjacent base station is performed using two separate fuzzy logic procedures for handoff triggering and handoff targeting. For triggering, inputs to the fuzzy logic procedure are the signal strength for communications with the serving base station, a time since a failure to complete execution of a handoff, and, for mobile-assisted handoff (MAHO), signal strengths of communications between the mobile terminal and each of the adjacent base stations. If handoff is triggered, then handoff targeting is performed at a central unit. For targeting, inputs to the fuzzy logic procedure are the monitored signal strengths between the mobile terminal and each of the adjacent base stations, supplied either from the mobile terminal using MAHO or from the base stations, and the current loads of the adjacent base stations. The targeting determines preferences for handoff of the mobile terminal to the different adjacent base stations, handoff then being executed in accordance with these preferences.
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Citations
20 Claims
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1. A method of controlling handoff in a cellular radio communications system, comprising the steps of:
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monitoring parameters for use in determining handoffs; in a handoff triggering step, applying fuzzy logic procedures to at least one monitored parameter to selectively determine a trigger for handoff of a mobile terminal from a serving base station, via which the mobile terminal is communicating, to another base station from among a plurality of adjacent base stations; in a handoff targeting step separate from the handoff triggering step and responsive to the handoff trigger, applying fuzzy logic procedures to at least one monitored parameter to determine preferences for handoff of the mobile terminal to different ones of said plurality of adjacent base stations; and executing handoff of the mobile terminal from the serving base station to one of said plurality of adjacent base stations in accordance with said preferences. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of controlling handoff of a mobile terminal from a serving base station, via which the mobile terminal is communicating, to another base station from among a plurality of adjacent base stations, in a cellular radio communications system, comprising the steps of:
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monitoring signal strength of communications between the mobile terminal and the serving base station; in a handoff triggering step, applying fuzzy logic procedures to at least one parameter comprising the monitored signal strength to selectively determine a handoff trigger; monitoring signal strengths of communications between the mobile terminal and each of said plurality of adjacent base stations; monitoring a current load of each of said plurality of adjacent base stations; in a handoff targeting step separate from the handoff triggering step and responsive to the handoff trigger, applying fuzzy logic procedures to parameters including the monitored signal strengths between the mobile terminal and each of said plurality of adjacent base stations and the current load of each of said plurality of adjacent base stations to determine preferences for handoff of the mobile terminal to different ones of said plurality of adjacent base stations; and executing handoff of the mobile terminal from the serving base station to one of said plurality of adjacent base stations in accordance with said preferences. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method of controlling handoff of a mobile terminal from a serving base station, via which the mobile terminal is communicating, to another base station from among a plurality of adjacent base stations, in a cellular radio communications system, comprising the steps of:
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monitoring signal strength of communications between the mobile terminal and the serving base station; in a handoff triggering step, applying fuzzy logic procedures to at least one parameter comprising the monitored signal strength to selectively determine a handoff trigger; in response to the handoff trigger, monitoring signal strengths of communications between the mobile terminal and each of said plurality of adjacent base stations; monitoring a current load of each of said plurality of adjacent base stations; in a handoff targeting step separate from the handoff triggering step and responsive to the handoff trigger, applying fuzzy logic procedures to parameters including the monitored signal strengths between the mobile terminal and each of said plurality of adjacent base stations and the current load of each of said plurality of adjacent base stations to determine preferences for handoff of the mobile terminal to different ones of said plurality of adjacent base stations; and executing handoff of the mobile terminal from the serving base station to one of said plurality of adjacent base stations in accordance with said preferences. - View Dependent Claims (20)
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Specification