Mobile station, mobile communication system, handover control method, handover control program and recording medium

Abstract

A mobile station applied to a mobile communication system in which data transmission from base stations to mobile stations is performed by using a first channel shared by a plurality of mobile stations and second channels exclusively used by respective mobile stations, including a data signal reception section that receives a data signal transmitted from one of the base stations through the first channel, a control signal reception section that selects and receives a control signal from the base station that is the transmission source of the data signal received by the data signal reception section, of the plurality of control signals transmitted through the second channel, and a reception quality information transmission section for transmitting to the base station information regarding reception quality of the control signal received by the control signal reception section.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a Divisional of and is based upon and claims the benefit of priority under 35 U.S.C. §120 from U.S. Ser. No. 10 / 282,138, filed Oct. 29, 2002, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a mobile station, mobile communication system, handover control method, handover control program and recording medium. [0004] 2. Related Background Art [0005] In mobile communication systems such as those of mobile telephones which are currently commonplace, service is provided with the entire service area divided into comparatively small zones called cells. Such a system is constituted by a plurality of base stations that cover the plurality of divided wireless zones and mobile stations that perform communication by setting up wireless channels with these base stations. [0006] Electromagnetic waves that are trans...

AI Technical Summary

Benefits of technology

[0009] Considering handover in a system in which PDSCH and A-DPCH are employed in combination as described above, although diversity handover can be applied in the case of A-DPCH, in the case of PDSCH, since this is shared by a plurality of users, it is difficult to achieve scheduling of transmission data at respective base stations, so it is difficult to apply diversity handover. Consequently, in a system in which PDSCU shared by a plurality of mobile stations and A-DPCH which is exclusively used by the respective mobile stations are employed in combination, hard handover is employed for the PDSCH while soft handover is employed for the A-DPCH. However, since PDSCH transmission control is performed in accordance with the reception quality of the control signal transmitted on the A-DPCH and, since soft handover applied to A-DPCH provided better reception quality than hard handover applied to PDS CU. The data reception quality on PDSCH may deteriorate due to a quality imbalance between PDSCH and A-DPCH. Furthermore, since lowered reception quality is associated with retransmission of non-arriving data, the overall amount of transmitted data increases and data addressed to other mobile stations suffer more delay. The number of subscribers, therefore, that can finally be accommodated is reduced.

Problems solved by technology

Considering handover in a system in which PDSCH and A-DPCH are employed in combination as described above, although diversity handover can be applied in the case of A-DPCH, in the case of PDSCH, since this is shared by a plurality of users, it is difficult to achieve scheduling of transmission data at respective base stations, so it is difficult to apply diversity handover.

The data reception quality on PDSCH may deteriorate due to a quality imbalance between PDSCH and A-DPCH.

Furthermore, since lowered reception quality is associated with retransmission of non-arriving data, the overall amount of transmitted data increases and data addressed to other mobile stations suffer more delay.

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