WO2006106561A1

WO2006106561A1 - Handover control method, base station control apparatus, and mobile station

Info

Publication number: WO2006106561A1
Application number: PCT/JP2005/005821
Authority: WO
Inventors: Koutarou Sugisawa; Hideji Wakabayashi
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2005-03-29
Filing date: 2005-03-29
Publication date: 2006-10-12

Abstract

A system, in which there exist base stations corresponding to different versions of standards, such as R99, Rel5 and Rel6, may have only a limited number of available channels. A handover control method wherein it is determined whether any base station selected from active sets is one for which E-DCH can be established; it is then determined whether the communication quality of the wireless link with any base station, for which the E-DCH can be established, can be maintained while the wireless links with the other base stations, for which the E-DCH cannot be established, are opened; and if the communication quality can be maintained, the E-DCH is used to communicate with the E-DCH-capable base station, while the wireless links with the other base stations, for which the E-DCH cannot be established, are opened.

Description

Specification

HANDOVER CONTROL METHOD, BASE STATION CONTROL DEVICE, AND MOBILE STATION

Technical field

[0001] The present invention provides W_CDMA (Wideband-Code Division Multiple

The present invention relates to a handover control method in a communication system using Access (broadband code division multiple access).

Background art

FIG. 15 is an explanatory diagram for explaining the configuration of a mobile communication system using the W-CDMA scheme. In FIG. 15, a mobile station 1500 (UE: User Equipment) is a device used by a user, such as a mobile phone or a mobile information terminal. Mobile station 1500 communicates with base station 150 1 (Node B) using radio. Base station 1501 transmits / receives user data and control signals to / from mobile station 1500 located within a predetermined area (cell), and controls transmission power and transmission timing of mobile station 1500. An “uplink” radio link that transmits data from mobile station 1500 to base station 1501 is an “uplink”, and a “downlink” radio link that transmits data from base station 1501 to mobile station 1500. This is called “downlink”. A base station controller 1502 (RNC: Radio Network Controller) relays data between the base station 1501 and the core network, and also performs line connection control, handover control, and the like of the radio line. Note that the base station 1501 and the base station controller 1502 constitute a radio access network (RAN), and in a communication system defined by the 3GPP (3rd Generation Partnership Project) standard, the RAN is a UTRAN (Universal Terrestrial RAN).

FIG. 16 is an explanatory diagram illustrating channels for performing wireless communication between mobile station 1500 and base station 1501. DCH1600 (Dedicated CHannel) is a channel for transmitting data, and is set in both the upstream and downstream directions. DCH1600 is a channel specified in 3GPP standard R9 9 (Release 1999). HS—DSCH 1601 (High Speed Downlink Shared CHannel) is a channel that is set when HSDPA (High Speed Downlink Packet Access) communication for transmitting a large amount of data in the downlink direction is started. HS—DSCH1601 is defined in 3GPP standard Rel5 (Release 5). E-DCH1 602 (Enhanced Dedicated CHannel) is a channel set in the uplink direction for large-capacity data transmission. E—DCH1602 is defined in Rel6 (Release 6) of the 3GPP standard. The current mobile communication system is operated in accordance with the specifications specified in R99 of the 3GPP standard, and the specifications specified in Re and Rel6 are expected to be introduced in the future.

[0004] In W-CDMA, a mobile station simultaneously performs communication by connecting multiple cells and radio links to perform communication, thereby combining signals from multiple base stations and improving the reception quality around the cell. Improved, uninterrupted communication can be realized. Multiple base stations that communicate with a mobile station at the same time are called members of the mobile station's “active set”. In other words, an active set is information about a plurality of base stations with which a certain mobile station is communicating. By performing soft handover, the mobile station can synthesize signals received from multiple base stations and improve communication quality. Further, the base station control device can improve communication quality by combining signals transmitted via a plurality of base stations. Since the base station controller synthesizes received data transmitted via a plurality of base stations, it can determine whether a transmission signal from a certain mobile station is properly transmitted. Therefore, retransmission control for determining whether to retransmit data to the mobile station is performed by the base station controller. When retransmission is necessary, the base station controller notifies the mobile station of a retransmission instruction signal with the same SN (Sequence Number) via a plurality of base stations. A method and a mobile communication system for performing soft handover and hard handover using adaptively changing thresholds are disclosed in Patent Document 1.

[0005] Patent Document 1: Japanese Translation of Special Publication 2003-525533

[0006] In order to transmit a large amount of data such as a moving image from a mobile station, it is necessary to set a large capacity channel for performing high-speed packet communication in the uplink. However, when the amount of data transmitted from the mobile station increases, the transmission power increases, and the amount of interference at the base station inevitably increases. Therefore, Rel6 describes that the scheduler provided in the base station performs scheduling processing for allocating radio resources to the mobile station. The base station performs scheduling processing in consideration of the amount of interference in the cell and controls transmission of each mobile station in the cell, thereby suppressing an increase in the amount of interference and improving throughput. But E Base stations that can assign _DCH to mobile stations must be compatible with Rel6. Base stations with Rel5 and R99 specifications can receive data from mobile stations using E-DCH. Can not.

[0007] In a transition period in which the systems defined in Rel5 and Rel6 are widespread, there is a possibility that base stations having different specifications of the corresponding standards, such as R99, Rel5, and Rel6, coexist. If a mobile station moves between cells managed by base stations of different versions, the channel used may be restricted. Non-Patent Document 1 discloses handover between base stations of different versions. According to Non-Patent Document 1, if the mobile station power EUL transmitted using EUL (Enhanced Up Link) to a Rel6-compatible base station cannot be used, and moves to a cell of a Re-compatible base station, E — It is disclosed that DCH transmission is stopped and switched to DCH.

[0008] Non-Patent Document 1: R1— 040962 "Proposal on RR / SI time multiplexing with

HS-DPCCH "

Disclosure of the invention

Problems to be solved by the invention

[0009] By the way, the following problems arise because the channel that can be used by the mobile station is limited by the version of the base station. In the system disclosed in Non-Patent Document 1 above, the mobile station has to transmit a large amount of data using DCH instead of E-DCH, so the amount of interference in the cell increases and throughput decreases. This causes a problem on the system side. In addition, for mobile stations, the use of E-DCH, which allows high-speed transmission, must be stopped and the DCH must be used, which causes a problem that it takes time to send the same amount of data. As described above, when transmitting large amounts of data, it is preferable for the system and mobile station to use E-DCH instead of DCH. Therefore, base stations that can use E-DCH and base stations that cannot use E-DCH It is preferable to remove the base stations compatible with Rel5 and R99 from the active set.

[0010] Also, in the case of DCH, since the base station control device performs retransmission control on each base station with the same sequential number (SN), it is possible to synthesize signals from the base stations on the mobile station side. is there. However, in the case of E-DCH, data retransmission control is performed by the base station. Implemented. When a mobile station communicates with multiple base stations using E-DCH, retransmission control is performed with a different sequential number from each base station. Cannot be synthesized. Therefore, the mobile station cannot perform soft handover to communicate with multiple base stations using E-DCH.

[0011] In addition, the format determined by Rel6 (for example, slot format), the power determined by Re or R99, and as a result of the change, the Re or R99 compatible base station is transmitted from the mobile station compatible with Rel6. A problem that the slot format cannot be recognized may also occur. For example, in R99, the slot format of uplink DPCCH (Dedicated Physical Control Channel) has pilot bit power ¾ bit, TPC (Transmission Power Command) bit bit, and TFCI (Transport Format Combination Indicator) bit 2 A slot consists of a total of 10 bits.

[0012] On the other hand, in Rel6, the uplink DPCCH slot format is 4 bits for the no-bit bit, 3 bits for the new control bit newly established in Rel6, 1 bit for the TPC bit, and 2 bits for the TFCI bit. One slot consists of 10 bits. In this case, the R99-compatible base station misrecognizes the slot format transmitted from the Rel6-compatible mobile station as the R99 pilot bit, the first 2 bits of the 4-bit pilot bit and the new restriction control bit, The last 1 bit of the new control bit and the TPC2 bit may be mistakenly identified as the R99 TPC bit.

[0013] In this way, for example, a slot format of a new specification such as base station power Rel6 corresponding to an old specification such as R99 cannot be recognized, and a malfunction may occur. Even when base stations with different specifications are mixed, the communication system with the new specification and the system with the old specification need to be guaranteed “Backward Compatibility”. is there. The present invention has been made to solve the above-described problems. In a mobile communication system in which base stations of different versions such as Rel6 or Re are mixed, a base station that cannot use E-DCH It is an object of the present invention to provide a mobile communication terminal or base station control device that restricts soft handover.

Means for solving the problem

[0014] In the handover control method according to the present invention, a predetermined mobile station transmits a dedicated physical channel. A base station selection process that selects a predetermined base station from an active set that records information related to the base station that is communicating, and a high-speed packet data channel that can transmit a large amount of high-speed packet data in the upstream direction A channel setting determination process for determining whether the first base station can be set or a second base station that cannot set a high-speed packet data channel, and in this channel setting determination process, the communication with the second base station is stopped. Whether communication with the dedicated physical channel with the first base station can be maintained, communication quality evaluation processing for evaluating communication quality between the first base station and the mobile station, and communication with the second base station stopped When the communication quality between the first base station and the mobile station is good, the active set determination process for deleting the second base station from the active set and the active set Based on Tsu preparative determining active set determined by the processing, it is intended to include the channel setting process that instructs to release the dedicated physical switch Yaneru the mobile station and the second base station.

[0015] The base station control device according to the present invention has a base station power selected from an active set in which a base station communicating with a predetermined mobile station via a dedicated physical channel is recorded. Determine whether it is the first base station that can set up a high-speed packet data channel that can transmit data, or a second base station that cannot set up a high-speed packet data channel, and stop communication with the second base station. If communication with the first base station can be maintained and the communication quality evaluation process is performed, and communication with the first base station can be maintained, the second base station is deleted from the active set. The base station and the base station and the active set controller to release the dedicated physical channel with the second base station based on the active set updated by the active set controller. And a radio resource management unit that instructs the mobile station.

[0016] The mobile station according to the present invention communicates with a predetermined mobile station via a dedicated physical channel, and the base station selected from the active set in which the base station is recorded has a large capacity and high speed in the uplink direction. Determined whether the first base station that can set up a high-speed packet data channel that can transmit packet data or the second base station that cannot set up a high-speed packet data channel, and stopped communication with the second base station If communication with the dedicated physical channel with the first base station can be maintained in the state, communication quality evaluation processing is performed, and if communication with the first base station can be maintained, the second base station is set to the active set. An active set controller to be removed from, Based on the active set updated by the active set control unit, a transmission unit that transmits a notification signal to the base station control device to release the dedicated physical channel with the second base station, and an instruction from the base station control device On the basis of this, a protocol processor for releasing a dedicated physical channel with the second base station is provided.

The invention's effect

[0017] A handover control method according to the present invention includes a base station that selects a predetermined base station from an active set in which information on a base station with which a predetermined mobile station is communicating via a dedicated physical channel is recorded. Selection processing and channel setting determination processing to determine whether the first base station can set a high-speed packet data channel capable of transmitting a large amount of high-speed packet data in the upstream direction or the second base station that cannot set a high-speed packet data channel In this channel setting determination process, whether communication with the dedicated physical channel with the first base station can be maintained while communication with the second base station is stopped, or between the first base station and the mobile station. If the communication quality evaluation process for evaluating the communication quality and the communication quality between the first base station and the mobile station are good while communication with the second base station is stopped, Based on the active set determination process for deleting the second base station from the set and the active set determined by the active set determination process, the individual physical channel between the second base station and the mobile station is released. In a mobile communication system with mixed versions of base stations, soft handover with base stations that cannot use E-DCH is restricted, and E-DCH is used preferentially. it can.

[0018] The base station control apparatus according to the present invention has a base station power selected from an active set in which a base station communicating with a predetermined mobile station via a dedicated physical channel is recorded. Determine whether it is the first base station that can set up a high-speed packet data channel that can transmit data, or a second base station that cannot set up a high-speed packet data channel, and stop communication with the second base station. If communication with the first base station can be maintained and the communication quality evaluation process is performed, and communication with the first base station can be maintained, the second base station is deleted from the active set. The base station and the base station and the active set controller to release the dedicated physical channel with the second base station based on the active set updated by the active set controller. Radio that instructs mobile stations Since a resource management unit is provided, in a mobile communication system where base stations of different versions coexist, soft handover with base stations that cannot use E-DCH is restricted, and E-DCH can be used preferentially. .

[0019] The mobile station according to the present invention communicates with a predetermined mobile station via a dedicated physical channel, and the base station selected from the active set in which the base station is recorded has a large capacity and high speed in the uplink direction. Determined whether the first base station that can set up a high-speed packet data channel that can transmit packet data or the second base station that cannot set up a high-speed packet data channel, and stopped communication with the second base station If communication with the dedicated physical channel with the first base station can be maintained in the state, communication quality evaluation processing is performed, and if communication with the first base station can be maintained, the second base station is set to the active set. To the base station controller to release the dedicated physical channel to the second base station based on the active set controller deleted from the active set controller and the active set updated by the active set controller. A transmission unit that transmits an intelligent signal and a protocol processing unit that releases a dedicated physical channel with the second base station based on an instruction from the base station control device are provided. In a mobile communication system, E-DCH can be preferentially used by limiting soft handover with base stations that cannot use E-DCH.

Brief Description of Drawings

FIG. 1 is a block diagram of a base station control device constituting a communication system according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a base station corresponding to Rel6.

FIG. 3 is a flowchart illustrating soft handover control processing in the communication system according to Embodiment 1 of the present invention.

FIG. 4 is a conceptual diagram showing a process for setting E-DCH during soft handover between base stations of different versions.

FIG. 5 is a flowchart showing details of active set determination processing.

FIG. 6 is a flowchart illustrating details of an active set update process.

FIG. 7 is a flowchart showing details of a communication quality evaluation process.

FIG. 8 is a flowchart showing details of communication quality evaluation processing. FIG. 9 is a block diagram of a mobile station that constitutes a communication system according to Embodiment 2 of the present invention.

FIG. 10 is a flowchart illustrating soft handover control processing in the communication system according to Embodiment 2 of the present invention.

FIG. 11 is an explanatory diagram for explaining base station version information notified from a base station control device to a mobile station.

FIG. 12 is a flowchart for explaining active set determination processing executed by a mobile station.

FIG. 13 is a flowchart explaining a soft handover one control process in the mobile communication system according to the third embodiment of the present invention.

FIG. 14 is a flowchart explaining a soft handover one control process in the mobile communication system according to the fourth embodiment of the present invention.

FIG. 15 is an explanatory diagram for explaining a configuration of a mobile communication system using a W-CDMA system.

FIG. 16 is an explanatory diagram for explaining a channel for performing wireless communication between a mobile station and a base station.

100 control unit, 101 transmission control unit, 102 radio resource management unit,

103 Active Set Quality Information Management Department, 104 Base Station Version Information Management Department,

105 Active set information manager, 106 Event receiver,

107 Active set control unit, 108 Base station version information determination unit,

200 control unit, 201 protocol processing unit, 202 DPCH transmission unit,

203 CPICH transmitter, 204 modulator, 205 power amplifier, 206 antenna,

207 Low noise amplifier, 208 demodulator, 209 DPCH receiver,

210 E— DCH receiver, 211 E— DPCCH receiver,

212 uplink quality measurement unit, 213 scheduling information processing unit,

214 Scheduling information storage unit, 400 mobile station, 401 Rel6 base station,

402 R99 base station, 403 DCH, 404 DCH, 405 E—DCH,

900 control unit, 901 protocol processing unit, 902 DPCH addition / deletion unit, 903 DPCH transmission section, 904 E— DCH addition Z deletion section,

905 E—DCH transmitter, 906 modulator, 907 power amplifier, 908 antenna,

909 Low noise amplifier, 910 demodulator, 911 CPICH receiver,

912 broadcast information receiving unit, 913 path loss measuring unit,

914 Base Station Version Information Management Department, 915 Active Set Information Management Department,

916 Active Set Control Unit, 917 Event Generation Unit,

918 Base station version information determination unit, 919 DPCH reception unit, 920 detection unit

1500 mobile station, 1501 base station, 1502 base station controller, 1600 DCH,

1601 HS— DSCH, 1602 E— DCH

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] Embodiment 1.

FIG. 1 is a block diagram showing a configuration of a base station control apparatus constituting the communication system according to Embodiment 1 of the present invention. The control unit 100 controls hardware and functions of each base station. The transmission control unit 101 is a unit that takes charge of retransmission control and guarantees link reliability. The radio resource management unit 102 manages radio resources such as power, code, and frequency band related to CDMA. The active set quality information management unit 103 stores the quality information of the radio link of each active set. The base station version information management unit 104 stores version information of the base stations being served thereby. The active set information management unit 105 stores the current active set state. The event receiving unit 106 receives a notification (event event) for requesting addition or deletion of a certain base station from the active set. The active set control unit 107 controls addition or deletion of the base station to the active set. Base station version information determination section 108 determines the version of the base station based on the base station version information stored in base station version information management section 104. A base station version information management unit 104 and a base station version information determination unit 108 are newly provided, and the other parts are existing parts.

[0023] FIG. 2 is a block diagram showing a configuration of a base station corresponding to Rel6. In Fig. 2, the control unit 200 sets the channel. The protocol processing unit 201 performs protocol processing such as channel setting and release. DPCH transmission section 202 is a dedicated physical channel (DPCH: Dedicated Performs processing to transmit (Physical Channel). A common pilot channel (CPICH: Common Pilot Channel) transmission unit 203 transmits a common pilot signal. Modulation section 204 modulates the signals output from DPCH transmission section 202 and CPICH transmission section 203. The power amplification unit 205 amplifies the output signal from the modulation unit 204 to a predetermined transmission power. The signal amplified to the transmission power by the power amplification unit 205 is transmitted from the antenna 206. On the other hand, the low noise amplifying unit 207 amplifies the reception signal received by the antenna 206. Demodulation section 208 demodulates the received signal amplified by low noise amplification section 207 and separates and outputs each channel such as DPCH, E_DCH, E-DPC CH (Enhanced-Dedicated Physical Control CHannel). The DPCH receiving unit 209 processes the DPCH signal output from the demodulating unit 208 and obtains data transmitted on the DPCH. The E-DCH receiving unit 210 processes the E-DCH signal output from the demodulating unit 208, and obtains large-capacity high-speed packet data transmitted by the E-DCH. The E-DPCCH reception unit 211 processes the E-DPCCH signal output from the demodulation unit 208. Uplink quality measuring section 212 measures uplink DPCCH communication quality. The scheduling information processing unit 213 processes scheduling information. The scheduling information storage unit 214 manages scheduling information. Scheduling information is information necessary for the base station to perform scheduling processing for allocating radio resources to terminals, and includes the transmission power margin of the mobile station and the amount of data transmitted by the mobile station.

FIG. 3 is a flowchart for explaining soft handover control processing in the communication system according to Embodiment 1 of the present invention. Fig. 4 is a conceptual diagram showing the process of setting E-DCH during soft handover between base stations of different versions. Fig. 4 (a) shows a soft handover state in which mobile station 400 communicates with Rel6-compatible base station 401 via DCH 403, and with R 99-compatible base station 402 via DCH 404. It is shown that. FIG. 4 (b) shows a state in which the DCH 404 with the base station 402 is disconnected when the mobile station 400 starts large-capacity data communication with the base station 401 using the E-DCH 405. FIG. The mobile station 400 shown in FIG. 4 is assumed to support Rel6.

Hereinafter, the operation shown in FIG. 3 will be described. Base station controller, core network When receiving an instruction from (Core Network) to assign E-DCH to a given mobile station in soft handover (step ST300), the active set of the mobile station (eg mobile station 400 in FIG. 4) is read. . Then, among the base stations recorded in this active set (for example, base stations 401 and 402 in FIG. 4), base stations that do not support E-DCH (base stations 402 corresponding to specifications other than Rel6) are active. An active set determination process for determining whether to remove the set is performed (step ST301). This active set determination processing includes processing for evaluating communication quality when DCH is disconnected from a base station that does not support E-DCH. As a result of the active set determination process in step ST301, the base station removed from the active set is deleted from the active set and recorded in, for example, the active set deletion list. Base stations recorded in the active set deletion list cannot use E-DCH, and even if DCH is disconnected, the mobile station does not cause communication quality degradation.

[0026] Referring to this active set deletion list, the base station controller releases the DCH with mobile station 400 to the base stations (for example, R99 compatible base station 402) registered in the active set deletion list. This is indicated using the NBAP (Node BA lication Part) protocol. At the same time, the mobile station 400 is instructed to release the DCH with the base station 402 using the RRC (Radio Resource Control) protocol (step ST302). In response to an instruction from the base station control device, mobile station 400 and base station 402 each release DCH (steps ST303 and ST304). On the other hand, the base station controller sets the E-DCH with the mobile station 400 for the base station recorded in the active set (for example, the Rel6-compatible base station 401 that can use the E-DCH). Instructed using the NBAP protocol. At the same time, the mobile station 400 is instructed to set up E-DCH with the base station 401 using the RRC protocol (step ST305). In response to an instruction from the base station controller, processing for setting E-DCH between the mobile station 400 and the base station 402 is executed (steps ST306 and 307).

FIG. 5 is a flowchart explaining the active set determination processing executed by the base station control device. FIG. 5 is a flowchart showing details of the active set determination process in step ST301 shown in FIG. The base station controller is transferred from the core network. When receiving an instruction to assign E-DCH to the mobile station (FIG. 3, step ST301), active set information management section 105 refers to the active set of the mobile station that sets E-DCH (step ST500). In this active set, a plurality of base stations with which mobile stations communicate via DPCH are recorded. Active set control section 107 selects one of a plurality of base stations recorded in the active set (step ST501), and performs a process of determining whether the selected base station can use E-DCH (step ST502). ). Whether or not the selected base station can use E-DCH is determined by the base station version information management unit 104 and the base station version information determination unit 108 based on the base station version information. For example, if the selected base station supports Rel6, E-DCH can be used. In this case, step ST503 is executed, and it is determined whether there are any unchecked base stations. On the other hand, if the selected base station supports Re or R99, E-DCH cannot be used. In this case, the process of step ST504 is executed.

[0028] In order for a mobile station that is currently in soft handover to transmit data using E-DCH, it stops D-CH transmission with a base station that does not support E-DCH and supports E-DCH. E-DCH needs to be set for the base station. However, if the radio link with a base station that does not support E-DCH is disconnected, the quality of the uplink radio link may deteriorate and communication may become impossible. Therefore, the base station controller according to the present invention, when deleting a base station that does not support E-DCH from the active set before deleting a base station that does not support E-DCH from the active set, Step ST504 is performed to determine whether the quality of the radio link with the corresponding base station can be maintained.

[0029] If the E—DCH incompatible base station is deleted from the active set and the DCH communication quality cannot be maintained (No in step ST504), the E—DCH incompatible base station is not deleted from the active set. E—Maintain DCH with base station not supporting DCH (step ST505). On the other hand, if the communication quality of DCH can be maintained even if the E—DCH incompatible base station is removed from the active set (Yes in step ST504), the E—DCH incompatible base station is deleted from the active set (step ST506). ). After step ST505 or step ST506 is executed, have all the base stations stored in the active set been checked? If it is determined (step ST503) and an unchecked base station remains (NO in step ST503), the processing after step ST501 is repeated. If there are no unchecked base stations remaining (Yes in step ST503), the mobile station determines whether E-DCH is unavailable (step ST507). When the mobile station cannot use E-DCH, it means that all base stations recorded in the active set do not support E-DCH, or if a base station that does not support E-DCH is removed from the active set. There are reasons such as inability to maintain DCH communication quality. Since the E—DCH bearer setting is instructed by the core network capability, if the E—DCH 禾 IJ is not possible (Yes in step ST507), the core network is notified that the E—DCH cannot be set. If E-DCH can be used (No in step ST507), the processing after step ST302 in FIG. 3 is executed.

[0030] The active set obtained by the base station controller in step ST500 of Fig. 5 is always updated such as addition or deletion of base stations in accordance with changes in the communication environment of the mobile station. FIG. 6 is a flowchart for explaining the details of the active set update process. In FIG. 6, event receiving section 106 receives an event transmitted from a mobile station (step ST600). Active set control section 107 determines whether the event transmitted from the mobile station is a request (event 1A) to add a certain base station to the active set (step ST601). If it is event 1A (Yes in step ST601), active set control section 107 adds the base station specified in event 1A to the active set (step ST602).

[0031] If the event transmitted from the mobile station is not event 1A (No in step ST601), the active set control unit 107 requests that the base station be deleted from the active set. (Event 1B) is determined (step ST603). If it is event 1B (Yes in step ST603), active set control section 107 deletes the base station specified in event 1B from the active set (step ST604). When the event transmitted from the mobile station is not event 1A or event 1B (No in step ST603), the active set control unit 107 determines that the base station in the active set is a predetermined base station. It is determined whether it is a request to request replacement (event 1C) (step ST605). If it is event 1C (Yes in step ST605), In step ST606, the active set control unit 107 performs processing for confirming the communication quality of the base station specified in event 1C.

[0032] The base station controller determines whether the communication quality of the base station specified in event 1C is better than a predetermined base station with a lower communication quality among the base stations registered in the active set. To do. If the base station specified in event 1C has better communication quality than the base station recorded in the active set (Yes in step ST606), the base station specified in event 1C is added to the active set, and event 1C A replacement process is performed to delete from the active set any base station whose communication quality is lower than that of the base station specified in (ST ST07 07). Then, the base station controller updates the active set based on the processing result of the above step (step ST608). When the event transmitted from the mobile station is not any of event 1A to event 1C (No in step ST605), the base station controller ends the process without performing the active set update process. If the communication quality of the base station specified in event 1C is worse than the communication quality of any base station registered in the active set (No in step ST606), communication with the base station specified in event 1C is possible. Since there is no need to replace the base station in the active set with good quality, the base station controller ends the process without updating the active set.

[0033] In step ST504 of FIG. 5, a communication quality evaluation process is performed to determine whether or not the DCH communication quality can be maintained with the base set not supporting E-DCH removed from the active set. FIG. 7 is a flowchart showing a first method of the communication quality evaluation process executed in step ST504 of FIG. The first method of this communication quality evaluation process is performed by the mobile station and notifies the base station controller of the result. In Fig. 7, the mobile station calculates the remaining available transmission power value (transmission power margin) by subtracting the maximum transmission power value allocated by the base station from the transmission power value used for the current transmission. (Step ST700). Then, by using the usable power value obtained in step ST700, it is determined whether the condition for maintaining the quality of the radio link is satisfied (step ST701). Details of step ST701 will be described later.

[0034] If the condition is satisfied (Yes in step ST701), it is determined that the communication quality can be maintained even if the DCH with the base station that does not support E-DCH is released, and the process ends. . If the condition is not satisfied (No in step ST701), it is determined that the communication quality cannot be maintained if the DCH with the base station that does not support E-DCH is released. Then, the base station controller is notified that the base station cannot be deleted from the active set. A signal notifying the evaluation result can be transmitted in the physical layer. It is also possible to multiplex and transmit on control channels such as DPCCH and E-DPCCH.

[0035] As the processing executed in step ST700 and step ST701, the "state" defined for the uplink data channel (DCH) data transmission format (TFC: Transport Format Combination) is referred to. It is possible. For example, user data transmitted on a physical channel such as DPDCH is transmitted from an upper layer such as a MAC (Media Access Control) layer to a physical layer via a transport channel. Such physical channels are multiplexed with a number of transport channel forces S. When transmitting data using DPDCH, the power of the upper protocol layer is communicated. The power to transmit the data multiplexing method and the data size (communication speed) per unit time on DPCCH and notify the receiver TFC Is notification information including “data multiplexing method” and “data size”. TFCI (TFC Index), which is the TFC index, is sent to the receiving side. State transitions (Support, Excess Power, Block) are defined for each TFC, and the “state” is selected according to the transmission power margin of the mobile station.

Among the states, “Excess-Power” is a state in which power shortage is detected for a certain period of time, and “Unavailable (Block)” is a state in which transmission is restricted due to power shortage. “Support” indicates a state where a power shortage has occurred, particularly, a state. These three states are transitioned when the transmitted data reaches the maximum transmission power (Pmax). If the maximum transmission power is reached, for example, from “Support” to “Power over (

The maximum transmission rate can be lowered by transitioning from “Excess-Power” or “Excess-Power” to “Block”. When the processing executed in step ST700 and step ST701 detects “Support”, it evaluates that the remaining transmission power of the mobile station has a margin (Yes in step ST701) and “Excess (Excess)”. -Power) "or" Unavailable (Block) "is detected, it is evaluated that the remaining transmission power of the mobile station is insufficient (No in step ST701). [0037] In this way, the mobile station determines whether the DCH with the Rel6-compatible base station can be maintained even if the DCH with the Rel5- or R99-compatible base station is released. Referring to the status, evaluate whether the communication quality of DCH with the Rel6-compatible base station can be secured, and notify the base station controller. The base station controller updates the active set according to the evaluation result transmitted from the mobile station.

FIG. 8 is a flowchart showing a second method of the communication quality evaluation process executed in step ST504 of FIG. In the second method of the communication quality evaluation process, the base station evaluates the uplink communication quality and notifies the base station controller, and the base station controller removes the base station not compatible with Rel6 from the active set. In this state, it is judged whether the communication quality of DCH can be maintained. Of the steps shown in FIG. 8, steps ST800 to ST803 are processes executed by the base station, and steps ST804 to ST806 are processes executed by the base station controller. The base station receives the uplink control channel (DPCCH) transmitted from the mobile station (step ST800). Then, the base station determines whether the communication quality of each received uplink control channel satisfies the condition, that is, whether the communication quality exceeds a predetermined level (step ST801). For example, the base station uses SIR (Signal to Interference ratio) as a threshold as a criterion for judging communication quality. This threshold is temporarily called the target SIR. In Step ST801, the base station obtains a received SIR from the received uplink control channel, and compares the received SIR with the target SIR to determine whether the quality of the upper control channel satisfies a predetermined level.

[0039] When it is determined that the communication quality of the uplink control channel satisfies a predetermined level (Yes in step ST801), the process of step ST804 executed by the base station controller is executed. On the other hand, when it is determined that the communication quality of the uplink control channel does not satisfy the predetermined level (No in step ST801), it is determined in step ST802 whether there is room for improving the communication quality of the uplink control channel. As a method of judging whether the communication quality of the uplink control channel is improved, it is possible to evaluate whether the transmission power control bit (TPC: Transmitter Power Control) that instructs the mobile station to increase the transmission power is continuously transmitted. ,. The base station transmits a TPC command to the mobile station in order to control the transmission power of the mobile station. Specifically, the TPC command that instructs the receiving SIR to reach the target SIR, Conversely, when the received SIR is greater than or equal to the target SIR, a TPC command (hereinafter referred to as the DOWN command) that indicates “D 0 WN” is transmitted. The mobile station receives and decodes the TPC transmitted from the base station, and changes the transmission power by ldB according to the command. When the mobile station receives the UP command from the base station, the mobile station increases the transmission power as long as the transmission power does not exceed the maximum transmission power (Pmax). However, if the mobile station transmits at the maximum transmission power and the communication quality of the received signal received at the base station is not good, the mobile station cannot expect improvement in communication quality by increasing the transmission power.

[0040] In step ST802, if the base station does not continuously transmit the UP command to the mobile station or transmits the DOWN command, the base station can improve the communication quality from the mobile station. Judge (Yes in step ST802). On the other hand, if the communication quality from the mobile station is not good despite the base station sending an UP command to the mobile station, the base station estimates that the communication quality from the mobile station cannot be improved. (No in step ST802). In this case, the base station transmits an event (or notification signal) to the base station control apparatus to notify that the uplink communication quality from the mobile station cannot be improved (step ST803). The base station controller determines whether an event indicating that communication quality cannot be improved has been transmitted from all of the base stations communicating with the predetermined mobile station (step ST804).

[0041] If all base stations included in the active set of the predetermined mobile station are transmitting events (Yes in step ST804), the mobile station is disconnected by disconnecting the radio link with any of the base stations. May not be able to communicate. Therefore, in order to add E-DCH, it is determined that communication quality cannot be secured if DCH with a base station that does not support E-DCH is disconnected (step ST805), and step 505 in FIG. Execute the process. On the other hand, if an event has not been notified from all the base stations included in the active set of the mobile station (No in step ST804), the base station that has not notified the event is compatible with release 6. (Step 806). If the base station that has not notified the event is Release 6 compatible (Yes in step ST806), it is determined that communication quality can be secured even if the DCH with the base station that does not support E—DCH is released. (Step ST807), Figure 5 Step ST506 shown is executed. On the other hand, if the base station that notified the event is release 6 (No in step ST806), the communication quality with the release 6 compatible base station is not good, so it is difficult to set E-DCH in the first place. — The core network is notified that DCH is unavailable (step 507).

[0042] As described above, the communication system according to the present invention removes Rel5 and R99 base stations that do not support E-DCH from the active set when the mobile station performs E-DCH transmission. , E— DCH transmission is preferentially executed. In this way, when E-DCH transmission is performed, by removing the Re and R99 base stations that do not support E-DCH from the active set, they can be used in communication systems with mixed versions of base stations. There is an effect that the active channel is not restricted.

[0043] Further, as described above, the communication system according to the present invention reduces the amount of interference in the cell because E-DCH assigned to the mobile station by scheduling is used when transmitting a large amount of data. This has the effect of improving the overall system throughput. In addition, since the mobile station can transmit a large amount of data using E-DCH over DCH, there is an effect that data transmission can be completed in a short time.

[0044] Further, as described above, in the communication system according to the present invention, the base station control device includes the Re

And active set decision processing to determine whether to remove base stations compatible with R99 from the active set. Then, when the DCH with the Rel5-compatible base station is released, communication with the Rel6-compatible base station (for example, DCH) can be maintained (or the active set determination process is performed in consideration of the ability to ensure quality) Therefore, it is possible to prevent E-DCH from being set between the base station and the mobile station with poor E-DCH communication quality, thus preventing the problem of communication interruption during E-DC H transmission. .

[0045] In the above description, the process of determining whether the DCH communication quality with the base station corresponding to E-DCH can be maintained in a state where the DCH with the base station not supporting E-DCH is removed. Is performed based on the transmission power margin of the mobile station. However, the above determination may be made using “path loss”. Specifically, focusing on the point that the quality is matched to the radio link with the least path loss during soft handover, the path loss (L1) of the radio link removed from the active set and the path loss of the other radio link are the smallest. , With path loss (L2) If the difference is negative (LI_L2 <0), the remaining transmittable power equal to or greater than the difference is used as the threshold value. If the difference does not become negative (L1_L2≥0), it is determined that there is no problem even if the target base station is removed from the active set without setting a threshold, assuming that no additional power is required. You can use the CPICH reception level instead of path loss.

[0046] Embodiment 2.

In the first embodiment described above, the base station controller performs an active set determination process for determining whether it is possible to remove the R e and R99 base stations that do not support E-DCH from the active set. . However, the mobile station may execute the process of determining whether a base station that does not support E-DCH may be removed from the active set. FIG. 9 is a block diagram of mobile stations constituting the communication system according to Embodiment 2 of the present invention. FIG. 10 is a flowchart illustrating soft handover control processing in the communication system according to Embodiment 2 of the present invention.

In FIG. 9, the control unit 900 sets a channel. The protocol processing unit 901 performs protocol processing such as channel setting and release. DPCH (Dedicated Physical Channel) addition / deletion section 902 controls setting, addition and deletion of DPCH. DPCH is a physical channel to which DCH, which is a transport channel, is mapped. DPCH transmission section 9 03 performs processing for transmitting DPCH such as channel coding. The E-DCH addition Z deletion unit 904 controls the setting, addition, and deletion of the E-DCH in the same manner as the DPCH addition Z deletion unit 902. The E-DCH transmission unit 905 performs processing for transmitting the E-DCH, similar to the DPCH transmission unit 903. The modulation unit 906 modulates signals such as DCH and E-DCH. The power amplification unit 907 amplifies the desired power. The antenna 908 transmits and receives signals. On the receiving side, the low noise amplification unit 909 amplifies a weak signal received by the antenna 908. Demodulation section 910 demodulates DPCH, CPICH (Common Pilot Channel) and the like. CPICH receiver 911 receives the common pilot signal.

Broadcast information receiving section 912 receives a scrambling code necessary for identifying a base station and version information corresponding to each scrambling code. The path loss measurement unit 913 obtains a propagation loss (path loss) from the CPICH reception level. Base station version information tube The management unit 914 stores version information of each base station. The active set information management unit 915 stores which base station is in the active set based on the CPICH information. Active set control section 916 controls active set determination processing based on active set information and base station version information. The event generation unit 917 creates an active set control event and transmits it to the protocol processing unit. Base station version information determination section 918 determines the version of the base station based on the information stored in base station version management section 914. 0 ^^^ Receiving section 919 performs processing on the received DPCH. The detection unit 920 detects the received uplink transmission power. A base station version information management unit 914 and a base station version information determination unit 918 are newly provided in the terminal according to the present invention.

In FIG. 10, the base station control apparatus notifies the mobile station of the specifications supported by the base station included in the active set (step ST1000). A scrambling code is used as identification information for identifying the base station. When receiving an instruction from the core network to assign E-DCH to a predetermined mobile station (step ST1001), the base station control device informs the mobile station that an instruction to set E-DCH has been generated from the core network. Notify (step ST1002). The mobile station that is instructed to set E-DCH reads the active set managed by the mobile station itself. Then, among the base stations recorded in the active set, a base station that does not support E-DCH (base station compatible with Rel5 or R99) is identified, and active set determination processing is performed to determine whether to remove from the active set. Perform (step ST1003). This active set determination process includes a process for evaluating communication quality when DCH is disconnected from a base station that does not support E-DCH.

[0050] As a result of performing the active set determination process in step ST1003, the mobile station transmits a notification signal to the base station controller (step ST1004). This notification signal includes information notifying that the E_DCH is not used when it is determined that the base station from which the active set power is deleted or E-DCH cannot be used. The base station controller determines whether the mobile station does not use E-DCH based on the notification signal transmitted from the mobile station (step ST1005). If the mobile station does not use E—DCH (Yes in step ST1005), E Stop using the _DCH bearer and notify the core network that E—DCH cannot be set (step ST1012). On the other hand, when the mobile station uses E-DCH (No in step ST1005), the base station controller releases the DCH to the base station designated by the mobile station so as to be deleted from the active set. Instruct (step ST1007). Also, the mobile station is instructed to release the DCH with the base station using the RRC (Radio Resource Control) protocol (step ST1006). In response to an instruction from the base station controller, the mobile station and the base station each release the DCH (steps ST1007 and 1008). Then, the base station controller instructs the base station recorded in the active set using the NBAP protocol to set E-DCH with the mobile station. At the same time, the mobile station is instructed to set up E-DCH with the base station using the RRC protocol (step ST1009). In response to an instruction from the base station controller, processing for setting E-DCH between the mobile station and the base station is executed (steps ST1010 and 1011). FIG. 11 shows the base station that the base station controller notifies the mobile station. It is explanatory drawing explaining station version information. The base station version information shown in FIG. 11 includes a scrambling code, which is information for identifying a plurality of base stations existing around the cell where the mobile station is located, and standards corresponding to these base stations. The version is associated. Since one scrambling code is always assigned to each base station, it is suitable for identifying the base station. Hereinafter, a method in which the base station controller notifies the mobile station of version information of the base station will be described. First, in order to notify the mobile station of the version information of the base station, a common channel or a dedicated channel can be considered as a channel used by the base station controller. When using a common channel for notification, BCH (Broadcast Channel) is used for notification. On the other hand, when notifying using the dedicated channel, notify using DCH.

When notifying by DCH, only the cell information in which the target mobile station is currently in the active set is notified. In addition to the scrambling code, CELL_ID can be used as information for the mobile station to identify the base station. In addition, as a method of notifying the mobile station of the version information of the base station, the base station control apparatus may notify the mobile station of the base station version information on “neighboring cell information”. FIG. 12 is a flowchart for explaining active set determination processing executed by the mobile station. FIG. 12 is a flowchart showing details of the active set determination process in step ST1003 shown in FIG. When receiving the E-DCH setting request notification from the base station controller, the mobile station refers to the base station version information (step ST1200) and selects one base station that does not support E-DCH (step ST1201). Then, when the selected E-DCH incompatible base station is deleted from the active set, the mobile station determines whether or not DCH communication quality with the E-DCH compatible base station can be secured (step ST1202). The processing in step 1202 is the same as that performed based on the transmission power margin of the mobile station described in the first embodiment, and a description thereof will be omitted. If the E—DCH incompatible base station is deleted from the active set and the DCH communication quality with the E—DCH compatible base station cannot be maintained (No in step ST1202), the E—DCH incompatible base station is set to the active set. The DCH with the base station not supporting E—DCH is maintained (step ST1203). On the other hand, if the communication quality of DCH with the E-DCH compatible base station can be maintained even if the E-DCH non-compliant base station is removed from the active set (Yes in step ST1202), the E-DCH non-compliant base station Is deleted from the active set (step ST1204).

[0053] After step ST1203 to step ST1204 are executed, it is determined whether all base stations stored in the active set have been checked (step ST1205). If there are unchecked base stations remaining (No in step ST1205). ), The process after step ST1201 is repeated. If there are no unchecked base stations remaining (Yes in step ST1205), the mobile station ends the active set determination process and executes the notification signal transmission process in step ST1004 in FIG. In step ST1004, if the E—DCH incompatible base station is deleted from the active set and the DCH communication quality with the E—DCH compatible base station cannot be maintained (No in step ST1202), the mobile station Transmits to the base station control device as a notification signal that E-DCH is not used. On the other hand, if the D-CH communication quality with the E-DCH compatible base station can be maintained even if the E-DCH incompatible base station is removed from the active set (Yes in step ST1202), the mobile station has been deleted from the active set. The base station is sent as a notification signal to the base station controller.

[0054] As described above, in the communication system according to the present invention, the mobile station performs E-DCH transmission. In this case, Rel5 and R99 base stations that do not support E-DCH are removed from the active set, and E-DCH transmission is preferentially executed. In this way, when performing E-DCH transmission, by removing base stations of Rel5 and R99 that do not support E-DCH from the active set, in a communication system in which base stations of different versions coexist, There is an effect that usable channels are not limited.

[0055] Also, as described above, the communication system according to the present invention reduces the amount of interference in a cell because E-DCH assigned to a mobile station by scheduling is used when transmitting a large amount of data. This has the effect of improving the overall system throughput. In addition, since the mobile station can transmit a large amount of data using E-DCH over DCH, there is an effect that data transmission can be completed in a short time.

[0056] Further, as described above, in the communication system according to the present invention, when the DCH with the Re (or R99) compatible base station is released, the communication (for example, DCH) with the Rel6-compatible base station is performed. Active set decision processing is performed in consideration of whether it can be maintained (or the ability to ensure quality), preventing E- DCH from being set between E-DCH compatible base stations and mobile stations with poor communication quality it can. Therefore, it is possible to prevent the problem that communication is interrupted during E-DCH transmission.

[0057] Further, as described above, in the communication system according to the present invention, the mobile station performs the active set determination process, so that the number of signaling to the base station controller can be reduced. In addition, since the mobile station bears the function of the base station controller, it is possible to reduce the overload of the base station controller and prevent problems such as congestion.

Embodiment 3.

In Embodiment 1, when a mobile station communicates with a plurality of base stations using DCH, the base station controller determines the active set when the core network is instructed to set E-DCH. We were processing. In some cases, the base station controller performs the active set determination process when the mobile station in communication using E-DCH moves to a cell of a base station that does not support Rel6. . In the following, the active set determination process of the base station controller executed when a mobile station in communication using E-DCH moves to a cell of a base station that does not support Rel6 will be described. FIG. 13 is a flowchart illustrating soft handover control processing in the mobile communication system according to Embodiment 3 of the present invention. In step ST1300, when a mobile station that is transmitting data with a Rel6-compatible base station using E-DCH moves to a cell managed by another base station, the reception level reaches the standard. The mobile station transmits an event to the base station controller so as to add the base station of the destination cell to the active set (step ST1301). The base station controller determines whether the base station notified to be added to the active set supports E-DCH, that is, supports Rel6 (step ST1302). If the base station notified from the mobile station can use E-DCH, for example, if it supports Rel6 (Yes in step ST1302), the active set should be added to add the base station to the active set. Change and instruct the terminal and the base station to set the DCH (step ST1303). The base station and mobile station instructed to set the DCH by the base station controller each set the DCH (steps ST1304 and 1305).

[0060] On the other hand, if the base station notified from the mobile station cannot use E-DCH, for example, if it is compatible with Re or R99 (No in step ST1302), the base station control device It is determined that the notified base station cannot be added to the active set. Then, the reason why it cannot be added to the active set is transmitted to the base station and mobile station (step ST1306). In this way, the reason why the base station and the mobile station are notified of the reason why they cannot be added to the active set is to prevent the terminal from excessively reducing the criteria for determining the necessity of handover.

[0061] As described above, in the communication system according to Embodiment 3 of the present invention, for example, the mobile station power transmitting E-DCH enters a cell under the jurisdiction of a base station that cannot use E-DCH. In this case, the base station of the destination cell is not added to the active set. By performing this process, handover to a base station that is not compatible with the previous version can be avoided, and the effect of preferential use of E-DCH and prevention of misinterpretation of the slot format can be achieved.

[0062] Embodiment 4.

In Embodiment 2, the mobile station communicates with multiple base stations using DCH. When the E-DCH setting is instructed by the core network, the base station controller performs the active set determination process. In some cases, the mobile station itself performs the active set determination process when the mobile station in communication moves to a base station cell that does not support Rel6 using E-DCH. In the following, the active set determination process executed when a mobile station in communication using E-DCH moves to a cell of a base station that does not support Rel6 will be described.

FIG. 14 is a flowchart illustrating soft handover control processing in the mobile communication system according to Embodiment 4 of the present invention. In FIG. 14, the mobile station transmits data to the Rel6-compatible base station using the ED CH (step ST1400), and the base station controller transmits the base station version information shown in FIG. 8 to the mobile station. Notify (step 1401). Mobile station power transmitting E—DCH When moving to a cell under the control of another base station, the base station of the target cell can determine whether it can use E-DCH by referring to the base station version information ( Step ST1402). If the base station of the target cell supports Re or R99 (Yes in step ST1402), the mobile station sends a notification requesting to add the base station of the target cell to the active set to the base station controller. The process ends without doing so. On the other hand, if the base station of the destination cell supports Rel6 (No in step 1402), the mobile station sends a notification requesting that the base station of the destination cell be added to the active set to the base station controller. Send (step ST1403).

[0064] Receiving the notification from the mobile station, the base station controller adds the designated base station to the active set and instructs the base station and the mobile station to set DCH (step ST1404). In response to an instruction from the base station controller, the mobile station and the base station each set a DCH (steps ST1405 and 1406). In the base station version information, the scrambling code for identifying the base station is associated with the version of the standard corresponding to the base station, and is notified from the base station controller to the mobile station via BCH or DCH. The mobile station refers to the base station version information using the scrambling codes of the destination cell and the base station of the neighboring cell, and determines whether the destination cell and the neighboring cell are compatible with E-DCH. To do.

[0065] As described above, in the communication system according to Embodiment 4 of the present invention, for example, E— Mobile station power transmitting DCH E—Do not add the base station of the target cell to the active set when a base station that cannot use DCH enters the cell. By performing this process, handover to a base station that is not compatible with the previous version can be avoided, and the effect of preferential use of E-DCH and prevention of misinterpretation of the slot format can be achieved.

[0066] Further, as described above, in the communication system according to the present invention, since the mobile station performs the active set determination process, the number of signaling to the base station control device can be reduced. Further, since the mobile station bears the function of the base station controller, it is possible to reduce the overload of the base station controller and prevent problems such as congestion.

Industrial applicability

[0067] The present invention can be applied to a terminal and a base station control device that perform soft handover and selective combination of received signals in a communication system in which base stations of different versions coexist.

Claims

The scope of the claims

[1] Base station selection processing for selecting a predetermined base station from an active set in which information on the base station with which the predetermined mobile station is communicating via a dedicated physical channel is recorded, and a high-speed packet with a large capacity in the uplink direction Channel setting determination processing for determining whether the first base station can set a high-speed packet data channel capable of transmitting data or the second base station that cannot set the high-speed packet data channel;

In this channel setting determination process, the ability to maintain communication with the first physical station and the dedicated physical channel while communication with the second base station is stopped, the first base station and the mobile A communication quality evaluation process for evaluating communication quality between stations;

If the communication quality between the first base station and the mobile station is good while communication with the second base station is stopped, the second base station is deleted from the active set. Active set decision processing,

A channel setting process for instructing to release the dedicated physical channel between the second base station and the mobile station based on the active set determined in the active set determination process. Control method.

[2] The communication quality evaluation process is performed based on a maximum transmission power allocated from the base station and a transmission power margin obtained from the transmission power used by the mobile station for data transmission. The handover control method according to item 1.

[3] The communication quality evaluation process is characterized by evaluating the transmission power margin based on the state of transmission control information selected according to the combination of transport channels for transmitting user data from the upper layer to the physical layer. The handover one control method according to claim 2, wherein:

[4] The communication quality evaluation process consists of a process for evaluating the communication quality of the uplink connected via the dedicated physical channel, and a transmission power control signal transmitted by the base station to control the transmission power of the mobile station. 2. The handover control method according to claim 1, further comprising: a process for determining whether or not the uplink communication quality can be improved based on.

[5] The base station power selected from the active set in which base stations communicating with a predetermined mobile station via dedicated physical channels are recorded. It is determined whether the first base station can set a high-speed packet data channel that can be transmitted or the second base station that cannot set the high-speed packet data channel, and communication with the second base station is stopped. When communication with the first base station can be maintained with the dedicated physical channel, communication quality evaluation processing is performed, and when communication with the first base station can be maintained, the second base station is An active set controller to be deleted from the active set;

A radio resource management unit that instructs the base station and the mobile station to release a dedicated physical channel with the second base station based on the active set updated by the active set control unit is provided. A base station controller characterized by that.

[6] The active set control unit is a communication evaluated by the mobile station based on a maximum transmission power allocated from the base station to the mobile station and a transmission power margin obtained from the transmission power used by the mobile station for data transmission. 6. The base station control device according to claim 5, wherein communication quality evaluation processing is performed based on the quality evaluation result.

[7] The active set control unit determines whether the base station is based on the uplink communication quality connected via the dedicated physical channel and the transmission power control signal transmitted to the mobile station to control the transmission power of the mobile station. 6. The base station control device according to claim 5, wherein communication quality evaluation processing is performed based on a communication quality evaluation result performed in the station.

[8] The base station selected from the active set in which the base station communicating with a predetermined mobile station via a dedicated physical channel is transmitted is capable of transmitting a large amount of high-speed packet data in the upstream direction. It is determined whether the base station is a first base station that can set a packet data channel or a second base station that cannot set the high-speed packet data channel, and the first base station stops communication with the second base station. If communication quality evaluation processing can be performed to maintain communication with the dedicated physical channel with the base station, and communication with the first base station can be maintained, the second base station is removed from the active set. The active set control to delete,

A transmission unit that transmits a notification signal to the base station controller so as to release the dedicated physical channel with the second base station based on the active set updated by the active set control unit; A mobile station, comprising: a protocol processing unit that releases an individual physical channel with the second base station based on an instruction from the base station controller.

[9] The active set control unit evaluates the communication quality of the uplink radio link based on the maximum transmission power allocated from the base station and the transmission power margin obtained from the transmission power used for data transmission to the base station. 9. The base station control device according to claim 8, wherein the base station control device is characterized in that:

[10] The active set control unit receives the specification information of the standard corresponding to the base station included in the active set, and based on this specification information, the base station included in the active set is the first base station or the second base station. The base station control device according to claim 8, wherein the base station control device determines whether the base station is used.