초록 ▼

The present invention relates to a mobile communication system, and more particularly, to a method for a handoff of a medium rate data call in a mobile communication system. In the present invention, if the pilot strength of the BTS in the active set to which a SCH is not allocated is smaller than t

The present invention relates to a mobile communication system, and more particularly, to a method for a handoff of a medium rate data call in a mobile communication system. In the present invention, if the pilot strength of the BTS in the active set to which a SCH is not allocated is smaller than the pilot strength of the BTS to which the SCH is not allocated for a predetermined period of time, the mobile station transmits the corresponding information to the base station by means of a PSMM, and the base station performs a handoff of the SCH resource according to the PSMM. In addition, if the base station receives the PSMM from the mobile station, whether or not the SCH is allocated is determined using the pilot strength of the corresponding BTS, reference threshold, and T?ADD. Therefore, frequent handoffs are prevented and the load of the mobile station is reduced because there is no need to compute a SCH reference threshold at every handoff request. Moreover, it is made possible to maintain a constant data rate and provide a medium rate data service by performing a handoff of an available SCH.

대표청구항 ▼

1. A method for handoff of a medium rate data call in a mobile communication system, comprising:comparing a pilot strength of a BTS (Base Station Transceiver Subsystem) to which a SCH (Supplemental Channel) is allocated to a pilot strength of a BTS to which the SCH is not allocated, without comparin

1. A method for handoff of a medium rate data call in a mobile communication system, comprising:comparing a pilot strength of a BTS (Base Station Transceiver Subsystem) to which a SCH (Supplemental Channel) is allocated to a pilot strength of a BTS to which the SCH is not allocated, without comparing the pilot strengths to a predetermined threshold value;transmitting a PSMM (Pilot Strength Measurement Message) from a mobile station to a base station including the BTS to which the SCH is allocated when the pilot strength of the BTS to which the SCH is allocated is smaller than the pilot strength of the BTS to which the SCH is not allocated; andperforming a handoff of the SCH to the BTS to which the SCH is not allocated, according to the PSMM.2. The method according to claim 1, wherein, for a medium rate data service, a FCH (Fundamental Channel) handoff procedure and a SCH handoff procedure are separately performed.3. The method according to claim 2, wherein a SCH handoff is performed with respect to a predetermined number of BTSs having a pilot strength strong enough to combine both FCH and SCH pilot signals by the mobile station among the BTSs communicating with the mobile station.4. A method for requesting a handoff of a medium rate data call of a mobile station, comprising:measuring a pilot strength of a BTS (Base Station Transceiver Subsystem) to which a SCH (Supplemental Channel) is allocated and a pilot strength of another BTS to which the SCH is not allocated;comparing the pilot strength of the BTS to which the SCH is allocated with the pilot strength of the another BTS to which the SCH is not allocated, without comparing the pilot strengths to a threshold; andtransmitting a PSMM (Pilot Strength Measurement Message) to a base station including the another BTS requesting a handoff, when the pilot strength of the BTS to which the SCH is allocated is smaller than the pilot strength of the BTS to which the SCH is not allocated as the result of the measurement.5. A method for performing a handoff of a medium rate data call of a base station:analyzing a PSMM (Pilot Strength Measurement Message) transmitted from a mobile station;comparing a pilot strength of a first BTS (Base Station Transceiver Subsystem) to which a SCH (Supplemental Channel) is allocated with a pilot strength of a second BTS to which the SCH is not allocated, if the allocation of the SCH is required, without comparing the pilot strengths to other variables;allocating the SCH to both of the first and second BTSs, if the pilot strength of the second BTS is larger than the pilot strength of the first BTS as the result of the comparison and the pilot strength of the first BTS is higher than T?ADD; andallocating the SCH to a BTS having a largest pilot strength, if analyzing the PSMM determines the SCH is not allocated to any BTS, when a DROP of the BTS to which the SCH is allocated is required.6. The method according to claim 5, wherein if the pilot strength of the second BTS is larger than the pilot strength of the first BTS, and the pilot strength of the first BTS to which the SCH is allocated is not higher than T?ADD, the allocation of the SCH to the second BTS is performed and the release of the SCH resource from the first BTS is performed.7. The method according to claim 5, wherein, as the result of comparing, if the pilot strength of the second BTS is larger than the pilot strength of the first BTS, it is judged that a new pilot signal corresponding to the pilot strength of the second BTS is to be added, and if the pilot strength of the BTS of which a handoff is to be performed is higher than a reference threshold, a handoff is performed by simultaneously allocating both FCH and SCH to the BTS of which the handoff is to be performed.8. The method according to claim 7, wherein the reference threshold, which is a value previously set by a radio environment test, is set higher than T?ADD for the ADD handoff, and is set higher than T?DROP for a DROP handoff.9. The method according to claim 5, wherein a total number of BTSs included in an active set is set to less than six.10. A handoff method, comprising:comparing a pilot strength of a first BTS (Base Station Transceiver Subsystem) to which a SCH (Supplemental Channel) is allocated with a pilot strength of a second BTS to which a SCH is not allocated, without referring to threshold values; andperforming a handoff to the second BTS when the pilot strength of the first BTS is smaller than the pilot strength of the second BTS.11. The method of claim 10, wherein a FCH (Fundamental Channel) handoff procedure and a SCH handoff procedure are separately performed.12. The method according to claim 10, wherein the SCH handoff is performed with respect to a predetermined number of BTSs having a pilot strength strong enough to combine both FCH and SCH pilot signals by the mobile station among the BTSs communicating with the mobile station.