EP0631451A2 — Handover scheme in cellular system using variable…

Claim 1

Independent Claim 129 words

A cellular system comprising a plurality of mobile stations and a plurality of base stations controlled under a switching center, wherein at least one of the mobile stations and the base stations includes: mobile station state detection means for detecting a mobile station state of each mobile station located within a cell of each base station; channel switching control parameter calculation means for calculating channel switching control parameters in accordance with the mobile station state detected by the mobile station state detection means; and control means for executing a channel switching operation for said each mobile station according to the channel switching control parameters calculated by the channel switching control parameter calculation means whenever said each mobile station is moving out of the cell of said each base station.

Claim 2

Dependent Claim 37 words

The cellular system of claim 1, wherein the mobile station state detection means, the channel switching control parameter calculation means, and the control means are provided in each one of the mobile stations and the base stations.

Claim 3

Dependent Claim 45 words

The cellular system of claim 2, wherein each one of the mobile stations and the base stations further includes data exchange means for exchanging data concerning the channel switching control parameters calculated by the channel switching control parameter calculation means provided therein with each other.

Claim 4

Dependent Claim 50 words

The cellular system of claim 3, wherein said data exchange means exchanges the data whenever any one of the channel switching control parameters calculated by the channel switching control parameter calculation means provided therein has changed for more than a predetermined reference value for judging a necessity of data exchange.

Claim 5

Dependent Claim 31 words

The cellular system of claim 4, wherein the predetermined reference value for judging a necessity of data exchange is identical to a reference value for judging a necessity of channel switching.

Claim 6

Dependent Claim 31 words

The cellular system of claim 4, wherein the predetermined reference value for judging a necessity of data exchange is higher than a reference value for judging a necessity of channel switching.

Claim 7

Dependent Claim 72 words

The cellular system of claim 1, wherein the mobile station state detection means detects the mobile station state indicating at least one of a received signal level for communication signals for said each mobile station, a position of said each mobile station, a moving speed of said each mobile station, a moving direction of said each mobile station, and an elapsed time since a previous channel allocation for said each mobile station.

Claim 8

Dependent Claim 96 words

The cellular system of claim 7, wherein the mobile station state detection means is provided in each mobile station, and said each mobile station includes at least one of: receiver means for detecting the received signal level for communication signals for said each mobile station; positioning means for detecting the position of said each mobile station and the moving direction of said each mobile station; speed meter means for detecting the moving speed of said each mobile station; and counter means for detecting the elapsed time since a previous channel allocation for said each mobile station.

Claim 9

Dependent Claim 144 words

The cellular system of claim 7, wherein the mobile station state detection means is provided in each base station, and said each base station includes at least one of: receiver means for detecting the received signal level for communication signals for said each mobile station; means for detecting the position of said each mobile station by measuring a time required for the communication signals for said each mobile station to reach said each base station from said each mobile station; radio arrival direction detection means for detecting the moving direction of said each mobile station; means for detecting the moving speed of said each mobile station by measuring the fading pitch of the communication signals for said each mobile station received at said each base station; and counter means for detecting the elapsed time since a previous channel allocation for said each mobile station.

Claim 10

Dependent Claim 81 words

The cellular system of claim 7, wherein the channel switching control parameter calculation means calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when the moving speed of said each mobile station is high, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the moving speed of said each mobile station is low.

Claim 11

Dependent Claim 73 words

The cellular system of claim 7, wherein the channel switching control parameter calculation means calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when the received signal level is low, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the received signal level is high.

Claim 12

Dependent Claim 130 words

The cellular system of claim 7, wherein the channel switching control parameter calculation means calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when a moving out of said each mobile station from the cell of said each base station is judged to be approaching according to the position and the moving direction of said each mobile station, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the moving out of said each mobile station from the cell of said each base station is judged to be not approaching according to the position and the moving direction of said each mobile station.

Claim 13

Dependent Claim 46 words

The cellular system of claim 7, wherein the channel switching control parameter calculation means calculates the channel switching control parameters such that an averaging time is extended and a reference value for judging a necessity of channel switching is raised when the elapsed time is short.

Claim 14

Independent Claim 133 words

A method of handover in a cellular system comprising a plurality of mobile stations and a plurality of base stations controlled under a switching center, the method comprising the steps of: detecting a mobile station state of each mobile station located within a cell of each base station, by at least one of said each mobile station and said each base station; calculating channel switching control parameters at said at least one of said each mobile station and said each base station, in accordance with the mobile station state detected at the detecting step; and executing a channel switching operation for said each mobile station according to the channel switching control parameters calculated at the calculating step whenever said each mobile station is moving out of the cell of said each base station.

Claim 15

Dependent Claim 30 words

The method of claim 14, wherein the detecting step, the calculating step, and the executing step are carried out by each one of the mobile stations and the base stations.

Claim 16

Dependent Claim 37 words

The method of claim 15, further comprising the step of: exchanging data concerning the channel switching control parameters calculated at the calculating step by each one of the mobile stations and the base stations with each other.

Claim 17

Dependent Claim 42 words

The method of claim 16, wherein the exchanging step is carried out whenever any one of the channel switching control parameters calculated at the calculating step has changed for more than a predetermined reference value for judging a necessity of data exchange.

Claim 18

Dependent Claim 30 words

The method of claim 17, wherein the predetermined reference value for judging a necessity of data exchange is identical to a reference value for judging a necessity of channel switching.

Claim 19

Dependent Claim 30 words

The method of claim 17, wherein the predetermined reference value for judging a necessity of data exchange is higher than a reference value for judging a necessity of channel switching.

Claim 20

Dependent Claim 68 words

The method of claim 14, wherein the detecting step detects the mobile station state indicating at least one of a received signal level for communication signals for said each mobile station, a position of said each mobile station, a moving speed of said each mobile station, a moving direction of said each mobile station, and an elapsed time since a previous channel allocation for said each mobile station.

Claim 21

Dependent Claim 76 words

The method of claim 20, wherein the calculating step calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when the moving speed of said each mobile station is high, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the moving speed of said each mobile station is low.

Claim 22

Dependent Claim 68 words

The method of claim 20, wherein the calculating step calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when the received signal level is low, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the received signal level is high.

Claim 23

Dependent Claim 125 words

The method of claim 20, wherein the calculating step calculates the channel switching control parameters such that an averaging time is shortened and a reference value for judging a necessity of channel switching is lowered when a moving out of said each mobile station from the cell of said each base station is judged to be approaching according to the position and the moving direction of said each mobile station, and the averaging time is extended and the reference value for judging a necessity of channel switching is raised when the moving out of said each mobile station from the cell of said each base station is judged to be not approaching according to the position and the moving direction of said each mobile station.

Claim 24

Dependent Claim 41 words

The method of claim 20, wherein the calculating step calculates the channel switching control parameters such that an averaging time is extended and a reference value for judging a necessity of channel switching is raised when the elapsed time is short.

Handover scheme in cellular system using variable channel switching control parameter setting based on mobile station state

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