Method and means for determining a handover in a radio communication system
First Claim
1. A method in a radio communication system for determining a handover of a connection (C1) established between a radio unit (100) and a first base station (101) to a second base station (105), where said first base station (101) is serving a serving cell (102) and said second base station (105) is serving a neighbouring cell (103), said method comprising:
- a) measuring (301) of a first received signal strength (RSSS) from said first base station (101);
b) measuring (302) of a second received signal strength (RSSNx) from said second base station (105);
c) measuring (303) at least a first (RXQUALS(RU)) and a second (RXQUALS(BTS)) communication-quality value in said serving cell (102);
characterised in said method further comprising;
d) calculating (306) a first power budget (pdgtS) for said serving cell (102) from said first received signal strength (RSSS);
e) calculating (307) a second power budget (pbgtNx) for said neighbouring cell (103) from said second received signal strength (RSSNx);
f) determining (306, 307) a first ranking value (RANKS) for said serving cell (102) based on said first power budget (pdgtS) and a second ranking value (RANKNx) for said neighbouring cell (103) based on said second power budget (pbgtNx);
g) calculating (309) a new ranking value (RANKNx(new)) for said neighbouring cell (103) from said second ranking value (RANKNx), wherein said new ranking value (RANKNx(new)) is calculated (309) by adding a communication-quality adjustment value (RxQualX(Adj)) to said second ranking value (RANKNx);
h) determining (310) if said new ranking value (RANKNx(new)) exceeds said first ranking value (RANKS);
if so, perform a handover (312) of said connection (C1) from said first base station (101) to said second base station (105).
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Abstract
The present invention relates to methods and means for determining handovers in a cellular radio communication system. Power-budgets for a serving and a target cell are calculated (301,302). A ranking value for both cells is determined from the power-budgets (306,307). A new ranking value for the target cell is calculated (309) by adding a specific adjustment value, dependent on the BER in the serving cell and the target cell and derived from a communication-quality table, to the ranking value of the target cell. A handover is performed if the new ranking value exceeds the ranking value of the serving cell.
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Citations
15 Claims
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1. A method in a radio communication system for determining a handover of a connection (C1) established between a radio unit (100) and a first base station (101) to a second base station (105), where said first base station (101) is serving a serving cell (102) and said second base station (105) is serving a neighbouring cell (103), said method comprising:
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a) measuring (301) of a first received signal strength (RSSS) from said first base station (101);
b) measuring (302) of a second received signal strength (RSSNx) from said second base station (105);
c) measuring (303) at least a first (RXQUALS(RU)) and a second (RXQUALS(BTS)) communication-quality value in said serving cell (102);
characterised in said method further comprising;
d) calculating (306) a first power budget (pdgtS) for said serving cell (102) from said first received signal strength (RSSS);
e) calculating (307) a second power budget (pbgtNx) for said neighbouring cell (103) from said second received signal strength (RSSNx);
f) determining (306, 307) a first ranking value (RANKS) for said serving cell (102) based on said first power budget (pdgtS) and a second ranking value (RANKNx) for said neighbouring cell (103) based on said second power budget (pbgtNx);
g) calculating (309) a new ranking value (RANKNx(new)) for said neighbouring cell (103) from said second ranking value (RANKNx), wherein said new ranking value (RANKNx(new)) is calculated (309) by adding a communication-quality adjustment value (RxQualX(Adj)) to said second ranking value (RANKNx);
h) determining (310) if said new ranking value (RANKNx(new)) exceeds said first ranking value (RANKS);
if so, perform a handover (312) of said connection (C1) from said first base station (101) to said second base station (105). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An arrangement in a radio communication system for determining a handover between a serving cell and a neighbouring cell, characterised in that said arrangement comprises:
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means for calculating (701) a first power budget for said serving cell and a second power budget for said neighbouring cell based on measured received signal strengths in said cells;
means for determining (702) a first ranking value from said first power budget and a second ranking value from said second power budget;
means for calculating a new ranking value (701) for said neighbouring cell based on said second ranking value and a communication-quality adjustment value (RxQualX(Adj)), wherein said communication-quality adjustment value (RxQualX(Adj)) is dependent on a measured communication-quality (RXQUALS, RXQUALNx, U) in said serving and neighbouring cell;
means for determining (703) if said new ranking value exceeds said first ranking value and, if so, selecting said neighbouring cell as a target cell; and
means for initiating a handover (704) to said target cell. - View Dependent Claims (13, 14, 15)
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Specification