US 7,068,626 B2Granted

Method of using a mobile unit to autonomously determine a serving cell

AssigneeInterDigital Technology Corporation

InventorsEldad Zeira, Ariela Zeira, Stephen E. Terry

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Abstract

A time division duplex method for determining whether to initiate handover of a mobile unit from a serving base station to a target base station, the method comprises receiving the broadcast channel from the serving base station (BCHser); calculating the serving base station received signal code power (RSCPser); receiving the broadcast channel from the target base station (BCHtar); calculating the target base station received signal code power (RSCPtar); determining interference signal code power for the serving base station (ISCPser); determining interference signal code power for the target base station (ISCPtar); calculating RSCPser/ISCPser; calculating RSCPtar/ISCPtar; and determining whether RSCPser/ISCPser is less than RSCPtar/ISCPtar, and if so, commencing handover from the serving base station to the target base station.

Claims8

Dependent claims

In a multi-cell communication system, a method of using a mobile unit to autonomously determine whether or not to initiate handover of the mobile unit from a serving base station located in a first cell of the communication system to a target base station located in a second cell of the communication system, the method comprising:

(a) the mobile unit receiving a first broadcast channel from the serving base station;
(b) the mobile unit autonomously determining the serving base station received signal code power (RSCPser);
(c) the mobile unit receiving a second broadcast channel from the target base station;
(d) the mobile unit autonomously determining the target base station received signal code power (RSCPtar);
(e) the mobile unit autonomously determining the first cell interference signal code power (ISCPser);
(f) the mobile unit autonomously determining the second cell interference signal code power (ISCPtar);
(g) the mobile unit forwarding to the serving base station the signal code powers autonomously determined by the mobile unit in steps (b), (d), (e) and (f);
(h) the serving base station determining a first signal code power ratio (RSCPser/ISCPser) for the serving base station by dividing the serving base station received signal code power (RSCPser) by the first cell interference signal code power (ISCPser);
(i) the serving base station determining a second signal code power ratio (RSCPtar/ISCPtar) for the target base station by dividing the target base station received signal code power (RSCPtar) by the second cell interference signal code power (ISCPtar);
(j) the serving base station comparing the first signal power ratio with the second signal power ratio;
and
(k) if the first signal power ratio is less than the second signal power ratio, the serving base station initiating the handover of the mobile unit from the serving base station to the target base station.

9 more elements

(a) the mobile unit autonomously determining the serving base station received signal code power (RSCPser) and the first cell interference signal code power (ISCPser);
(b) the mobile unit autonomously determining the target base station received signal code power (RSCPtar) and the second cell interference signal code power (ISCPtar);
(c) the mobile unit forwarding to the serving base station the signal code powers autonomously determined by the mobile unit in steps (a) and (b);
(d) the serving base station determining a first signal code power ratio (RSCPser/ISCPser) for the serving base station by dividing the serving base station received signal code power (RSCPser) by the first cell interference signal code power (ISCPser);
(e) the serving base station determining a second signal code power ratio (RSCPtar/ISCPtar) for the target base station by dividing the target base station received signal code power (RSCPtar) by the second cell interference signal code power (ISCPtar);
(f) the serving base station comparing the first signal power ratio with the second signal power ratio;
and
(g) if the first signal power ratio is less than the second signal power ratio, the serving base station initiating the handover of the mobile unit from the serving base station to the target base station.

5 more elements

Dependencies are inferred from the claim text.