HK1069489B

HK1069489B - Controller and control method for mobile communication system

Info

Publication number: HK1069489B
Application number: HK05101791.4A
Authority: HK
Inventors: 田上胜巳
Original assignee: 日本电气株式会社
Priority date: 2003-03-19
Filing date: 2005-03-01
Publication date: 2007-11-09

Description

Controller and control method for mobile communication system

Technical Field

The present invention relates to a mobile communication system and a controller and a control method used therein.

Background

In a cellular mobile communication system, a mobile station for performing communication, including voice communication, is handed over when moving between radio areas (cells) corresponding to radio base stations. During the handover procedure, the mobile station transmits radio signals to a plurality of radio base stations involved in the handover. The radio base station involved in the handover transmits a user signal included in a radio signal received from the mobile station to the radio base station controller, and the radio base station controller combines and transmits the received user signal to the core network via the mobile communication switching center.

The radio base station controller receives signals from the core network via the mobile communication switching center and transmits the received signals to the plurality of radio base stations involved in the handover. The radio base station involved in the handover transmits signals received from the radio base station controller to the mobile station, which combines the signals received from the radio base station involved in the handover.

Meanwhile, a high-speed data communication method dedicated to data communication has been developed to be adopted in a cellular mobile communication system. For example, the HSDPA (high speed downlink packet access) technology in a W-CDMA (wideband code division multiple access) mobile communication system and the EV-DO (evolved high-speed-dedicated data only) technology in a CDMA2000 system are both in accordance with the above-described high-speed data communication method. For example, 3GPP TS 25.308 v5.3.0 and the like specify HSDPA, while 3GPP2 S.R00232.0 and the like specify EV-DO.

In published and unexamined japanese patent application No.2001-217770, an outer loop transmission power control method for a mobile station during handover in a mobile communication system is disclosed. In this method, a mobile station communicates with only one radio base station which controls the transmission power of the mobile station based on the quality of a signal received from the mobile station. When a mobile station performs handover, a control station combines reception qualities of a plurality of radio base stations involved in the handover. The wireless base station controller controls the transmit power of the mobile station based on the combined reception quality.

Even if communication including voice communication and high-speed data communication are simultaneously performed, the quality of cellular mobile communication can be improved by performing outer loop control. However, satisfactory results have not been obtained so far.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved wireless communication system.

According to a first aspect of the present invention, there is provided a wireless communication system comprising: a plurality of base stations that simultaneously communicate with a mobile station by receiving radio signals relating to a first communication type transmitted by the mobile station; a specific base station that communicates with the mobile station by receiving a radio signal relating to a second communication type different from the first communication type; a controller that receives signals from the plurality of base stations based on the radio signals relating to the first communication type and receives signals from the specific base station based on the radio signals relating to the second communication type, wherein the controller transmits a first control signal to the plurality of base stations and the specific base station on the basis of the signals based on the radio signals relating to the second communication type received from the specific base station.

According to a second aspect of the present invention, there is provided a controller for a mobile station to simultaneously communicate with a plurality of base stations in a wireless communication system, comprising: a receiver that receives a plurality of signals relating to a first communication type from a plurality of base stations, and receives a signal relating to a second communication type different from the first communication type from a specific base station; and a transmitter coupled to the receiver, which transmits a control signal generated based on the signal related to the second communication type received by the receiver from the specific base station to the plurality of base stations and the specific base station.

Drawings

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

fig. 1 shows the structure of a mobile communication system;

FIG. 2 shows the structure of a processor within a wireless base station controller;

FIG. 3 shows the structure of an outer loop processor;

fig. 4 illustrates the operation of the mobile communication system;

figure 5 illustrates the operation of a wireless base station controller;

fig. 6 illustrates the operation of the mobile communication system;

figure 7 illustrates the operation of a wireless base station controller;

fig. 8 shows a signal format between a wireless base station and a wireless base station controller.

Detailed Description

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited by the following description. Furthermore, although specific details are set forth in the following description and figures to provide an understanding of the invention, the invention is not limited to these specific details. Details which are not necessary for an understanding of the present invention have been omitted in order not to obscure the explanation of the present invention.

Fig. 1 shows a structure of a mobile communication system according to an embodiment of the present invention. The mobile communication system according to the embodiment of the present invention may be, for example, a CDMA (code division multiple access) mobile communication system. The mobile communication system of the embodiment of the present invention includes a mobile station 21, radio base stations 22-1 to 22-n, a radio base station controller 23, a mobile communication switching device 24, and a communication network 200.

The mobile communication system according to the embodiment of the present invention can simultaneously perform high-speed data communication dedicated to data communication and communication including voice communication. In high-speed data communication dedicated to data communication, several functions including soft handover are not supported. Therefore, a mobile station performing high-speed data communication can communicate with only one radio base station at the same time. While a mobile station communicates with multiple base stations simultaneously during a handoff procedure in communications that include voice communications, such communications that include voice communications are referred to as conventional communications in the following discussion to distinguish them from high speed data communications.

The mobile station 21 communicates with the communication network 200 via the radio base stations 22-1 to 22-n, the radio base station controller 23, and the mobile communication switching center 24. Mobile station 21 may be simultaneously engaged in high-speed data communications and conventional communications. The high speed data communication may be, for example, W-CDMA HSDPA or CDMA2000 EV-DO. During the handover procedure, the mobile station 21 transmits radio signals including user signals related to conventional communications to the plurality of wireless base stations 22-1 to 22-n and receives such radio signals from the wireless base stations 22-1 to 22-n. However, the mobile station 21 transmits only a radio signal including a user signal relating to high-speed data communication to one of the plurality of radio base stations 22-1 to 22-n and receives only such a radio signal from the one of the radio base stations 22-1 to 22-n. Further, the mobile station 21 according to the embodiment of the present invention controls the transmission power of the radio signal to the radio base stations 22-1 to 22-n based on the transmission power control signal contained in the radio signal received from the radio base stations 22-1 to 22-n. The procedure of controlling the transmission power described in 3GPP TS 25.214v5.3.0 can be applied to the embodiments of the present invention.

The radio base stations 22-1 to 22-n receive user signals as radio signals from the mobile station 21, demodulate the radio signals received from the mobile station 21, and obtain quality information from the radio signals. The quality information according to an embodiment of the invention is error information. The error information may indicate error rate, CRC (cyclic redundancy code), etc. The error information here may be obtained from a Viterbi decoder (Viterbi decoder) or a high speed decoder (Turbo decoder). The radio base stations 22-1 to 22-n transmit the obtained error information to the radio base station controller 23 together with the user signal.

Also, the radio base stations 22-1 to 22-n receive the signal-to-interference ratio (SIR) targets of the user signals and the radio signals received by the radio base stations 22-1 to 22-n from the mobile station 21 from the radio base station controller 23. The SIR target is a quality target generated by the wireless base station controller based on the error information, as will be explained in detail later. The radio base stations 22-1 to 22-n generate transmission power control signals for controlling the transmission power of radio signals transmitted by the mobile station 21 based on the SIR targets and the calculated SIRs of the radio signals received from the mobile station 21. The process of generating a transmit power control signal described in 3GPP TS 25.214v5.3.0 may be applied to embodiments of the present invention.

The transmission power control signal according to an embodiment of the present invention commands an increase or decrease in the transmission power of the mobile station 21. However, the transmit power control signal may command control of the transmit power to a particular value.

The wireless base stations 22-1 to 22-n transmit the user signals and the transmission power control signals as radio signals to the mobile station 21.

The wireless base station controller 23 receives the user signals and their quality information from the wireless base stations 22-1 to 22-n and transmits the received user signals to the communication network 200 via the mobile communication switching center 24. The quality information according to an embodiment of the present invention is the above-described error information.

Also, during the handover procedure, the radio base station controller 23 receives the user signal transmitted from the mobile station 21 via the radio base station involved in the handover among the radio base stations 22-1 to 22-n. In this case, the wireless base station controller 23 selectively combines the user signals received from the plurality of wireless base stations and transmits them to the communication network 200 via the mobile communication switching center 24.

The wireless base station controller 23 receives a user signal from the communication network 200 via the mobile communication switching center and transmits the received user signal to one of the wireless base stations 22-1 to 22-n that communicates with the mobile station 21. Also, during the handover procedure, the radio base station controller 23 transmits the received user signal to the plurality of radio base stations involved in the handover procedure among the radio base stations 22-1 to 22-n.

The structure of the wireless base station controller will now be explained in detail. Fig. 2 is a block diagram showing the structure of the processor 1 included in the wireless base station controller 23. The processor 1 is constituted by circuit processors 11-1 to 11-n, a combination processor 12, a distribution processor 13, an outer loop processor 14, and a central processor 15.

The circuit processors 11-1 to 11-n receive signals from the wireless base stations 22-1 to 22-n, respectively, via the circuit 101, and supply the signals received from each of the wireless base stations 22-1 to 22-n to the combination processor 12.

As shown in fig. 8, signals communicated between the wireless base stations 22-1 to 22-n and the wireless base station controller 23 include a user signal a1 and a control signal a 2. The control signal a2 is a control signal used between the wireless base stations 22-1 to 22-n and the wireless base station controller 23. The control signal a2 includes error information as quality information of the user signal a1 received and demodulated by the radio base stations 22-1 to 22-n.

The circuit processors 11-1 to 11-n process the control signal a2 contained in each of the signals received from the wireless base stations 22-1 to 22-n and supply the processed control signal a2 as signals 111 to 11n to the outer loop processor 14. Also, the circuit processors 11-1 to 11-n receive, from the allocation processor 13, the SIR targets of the user signals to be transmitted to the mobile station 21 and the radio signals received by the radio base stations 22-1 to 22-n. The circuit processors 11-1 to 11-n transmit a user signal to be transmitted to the mobile station 21 and an SIR target as control signals to each of the radio base stations 22-1 to 22-n.

The combination processor 12 transmits the user signals received from the circuit processors 11-1 to 11-n to the mobile communication switching center 24 via the circuit 102. During the switching process, the combination processor 12 selects and combines user signals that meet the quality requirements based on error information contained in the control signals a2 of the signals received from the circuit processors 11-1 to 11-n. Meeting the quality requirement may indicate an error rate less than a certain value, no errors in terms of CRC, and so on. For example, the combination processor 12 selects one user signal satisfying the quality requirement based on the error information for each frame from among the user signals received from the plurality of radio base stations, and transmits the selected user signal to the communication network 200 via the mobile communication switching center 24.

In this case, the combination processor 12 transmits the combined user signal to the mobile communication switching center 24 via the circuit 102, and, if the error information on all the user signals received from the circuit processors 11-1 to 11-n does not satisfy the quality requirement, transmits the combined error information as a signal 120 to the outer loop processor 14.

The central processor 15 generally controls the mobile communication system. The central processor 15 controls whether or not high-speed data communication is performed, and through which base station high-speed data communication is performed. Also, the central processor provides a set signal 130 to the extrinsic cycle controller 14, as will be explained in more detail later.

Fig. 3 is a block diagram showing the structure of the outer loop processor 14. The outer loop processor 14 is constituted by a selector 141 and a control signal generator 142. In the outer loop processor 14, signals 111 to 11n from the circuit processors 11-1 to 11-n and a control signal 120 from the combination processor 12 are input to a selector 141.

The selector 141 selects one from the signals 111 to 11n and the signal 120 based on the setting signal 130 from the central processing unit 15, and supplies the selected one to the control signal generator 142. The setting signal 130 from the central processor 15 will be explained in more detail later.

The control signal generator 142 generates an SIR target as a quality target of the radio signals received from the radio base stations 22-1 to 22-n based on the signals 111 to 11n and the signal 120 input from the selector 141, and then outputs the generated SIR target to the assignment processor 13.

Referring again to fig. 2, the distribution processor 13 receives user signals to be transmitted to the mobile station 21 from the mobile communication switching center 24 via the circuit 102 and distributes the received user signals to the circuit processors 11-1 to 11-n. Also, allocation processor 13 allocates SIR targets received from outer loop processor 14 to circuit processors 11-1 through 11-n.

Fig. 4 illustrates an operation procedure of a mobile communication system according to an embodiment of the present invention. The operation of the CDMA mobile communication system according to the embodiment of the present invention will be explained with reference to fig. 1 to 5 and fig. 8. The mobile station 21 communicates with the network 200 via the radio base stations 22-1 to 22-n, the radio base station controller 23, and the mobile communication switching center 24. Also, the mobile station 21 performs handover via the radio base stations 22-1, 22-2, and 22-3.

The mobile station 21 transmits a radio signal to the radio base stations 22-1 to 22-3 (S11). Each of the wireless base stations 22-1 to 22-3 receives the user signal as a radio signal from the mobile station 21 (S12), and demodulates the radio signal received from the mobile station 21 to obtain the user signal and error information of the user signal from the received radio signal (S13). Also, the radio base stations 22-1 to 22-3 calculate the SIR of the radio signal received from the mobile station 21 to generate a transmission power control signal for uplink transmission power control (S14). The wireless base stations 22-1 to 22-3 then transmit the received user signal a1 and the control signal a2 including error information to the wireless base station controller 23 (S15).

Fig. 5 shows the operation of the wireless base station controller in detail (S16). The circuit processors 11-1 to 11-3 in the wireless base station controller 23 receive signals from each of the wireless base stations 22-1 to 22-3 (S161). Also, the circuit processors 11-1 to 11-3 supply the received signals to the combination processor 12, and supply the control signal a2 included in the received signals, for example, the signals 111 to 113, to the outer loop processor 14 (S162).

The combination processor 12 selects and combines the user signals satisfying the quality requirement based on the error information contained in the control signal a2 of the signals received from the circuit processors 11-1 to 11-3 (S163). In this case, the combining processor 12 transmits the combined user signal to the mobile communication switching center 24 via the circuit 102 (S164). Also, if all the error information received from the circuit processors 11-1 to 11-3 do not satisfy the quality requirement, the combination processor 12 combines the error information and supplies the combined error information as the signal 120 to the outer loop processor 14 (S165).

Selector 141 of outer loop processor 14 receives signals 111 through 113 from circuit processors 11-1 through 11-3 and also receives signal 120 from combining processor 12. The selector 141 selects one of the control signals 111 to 113 and the control signal 120 based on the setting signal 130 from the central processor 15 within the wireless base station controller 23, and supplies it to the control signal generator 142.

If the mobile station 21 does not perform high-speed data communication, the central processor 15 supplies the setting signal 130 to the selector 141 in the outer loop processor 14, the setting signal 130 instructing the selector 141 to select the control signal 120 and supplying it to the control signal generator 142 (S166). This control will be referred to as control process 1 hereinafter. In this case, when the control signal 120 has been supplied from the selector 141, the control signal generator 142 generates an SIR target, and supplies the generated SIR target to the allocation processor 13 (S168). The distribution processor 13 distributes the SIR target received from the control signal generator 142 to the circuit processors 11-1 to 11-3 together with the user signal received from the mobile communication switching center 24 via the circuit 102 (S1610). The circuit processors 11-1 to 11-3 transmit the received user signals and SIR targets to the radio base stations 22-1 to 22-3, respectively (S1611).

Referring again to fig. 4, the radio base stations 22-1 to 22-3 receive the user signals and the SIR targets from the radio base station controller 23, and then the SIR targets of the radio base stations 22-1 to 22-3 are updated (S17). The radio base stations 22-1 to 22-3 generate transmission power control signals for controlling the transmission power of the radio signals transmitted by the mobile station 21 based on the updated SIR targets and the SIR calculated in step S14 (S18). Also, the radio base stations 22-1 to 22-3 transmit the user signals and the generated transmission power control signals to the mobile station 21 (S19).

The mobile station 21 receives the user signal and the transmission power control signal from the radio base stations 22-1 to 22-3 (S20). Also, the mobile station 21 controls the transmission power of the radio signal to the radio base stations 22-1 to 22-3 based on the received transmission power control signal (S21).

In this manner, if the mobile station 21 does not perform high-speed data communication, the SIR target is updated only when the error rate information associated with all the user signals received by the radio base stations 22-1 to 22-3 does not satisfy the quality requirement. However, as described below, if the mobile station 21 performs normal communication and high-speed data communication at the same time, the SIR target must be updated in a different procedure.

As described above, the mobile station 21 transmits a radio signal relating to high-speed data communication to only one of the radio base stations 22-1 to 22-n, and receives such a radio signal from only the one radio base station. Here, the mobile station 21 performs transmission and reception of signals relating to high-speed data communication with the radio base station 22-2, that is, the mobile station 21 transmits and receives only user signals relating to high-speed data communication with respect to the radio base station 22-2. Therefore, if the control procedure 1 is executed, when high-speed data communication is performed together with normal communication, the quality information of the user signal related to the high-speed data communication received by the radio base station 22-2 will continuously fail to satisfy the quality requirement, and then the high-speed data communication will be deteriorated. For example, in the case where the error information on the user signal relating to the normal communication received by the radio base station 22-1 satisfies the quality requirement, the SIR target in the radio base stations 22-1 to 22-3 is not updated even if the error information on the signal relating to the high-speed data communication received by the radio base station 22-2 does not satisfy the quality requirement. Therefore, the error information of the user signal related to the high speed data communication received by the radio base station 22-2 will continuously fail to satisfy the quality requirement, and then the high speed data communication will be deteriorated.

Therefore, when the mobile station 21 performs high-speed data communication, the control procedure 2 described below is executed. In the control process 2, the steps from S11 to S165 are the same as those in the control process 1. Referring again to fig. 5, during the control process 2, the central processor 15 detects that high speed data communication is being conducted with the base station 22-2. The central processor supplies the setting signal 130 to the selector 141, instructing to select the signal 112 related to the user signal relating to the high-speed data communication from the signals 111 to 113 (S167). Here, since the central processor 15 controls whether or not high-speed data communication is performed between the mobile station 21 and any one of the radio base stations, the central processor 15 can detect which of the signals 111 to 113 is related to the user signal relating to high-speed data communication. The selector 114 provides the signal 112 to the control signal generator 142 based on the setting signal 130 from the central processor. The control signal generator 142 generates an SIR target of a radio signal, which is transmitted by the mobile station 21 and received by the radio base stations 22-1 to 22-3, based on the input signal 112. Then, the control signal generator 142 supplies the generated SIR target to the allocation processor 13 (S169). The distribution processor 13 distributes the SIR target received from the control signal generator 142 to the circuit processors 11-1 to 11-3 together with the user signal received from the mobile communication switching center 24 via the circuit 102 (S1610). The circuit processors 11-1 to 11-3 transmit the received user signals and SIR targets to the radio base stations 22-1 to 22-3, respectively (S1611).

Referring again to fig. 4, the radio base stations 22-1 to 22-3 receive the user signals and the SIR targets from the radio base station controller 23, and then the SIR targets of the radio base stations 22-1 to 22-3 are updated (S17). The radio base stations 22-1 to 22-3 generate transmission power control signals for controlling the transmission power of the radio signals transmitted by the mobile station 21 based on the updated SIR targets and the SIR calculated in S14 (S18). Also, the radio base stations 22-1 to 22-3 transmit the user signals and the generated transmission power control signals to the mobile station 21 (S19).

In the case where the mobile station 21 performs high-speed data communication, by executing the above-described control procedure 2, the error information of the user signal relating to the high-speed data communication does not continuously satisfy the quality requirement any more. Thus, the quality of high-speed data communication is improved. As described above, the case where the mobile station 21 performs transmission and reception of signals relating to high-speed data communication with the radio base station 22-2 is considered. In this case, for example, even if the error information on the user signal relating to the normal communication received by the radio base station 22-1 satisfies the quality requirement, if the error rate information on the signal relating to the high-speed data communication received by the radio base station 22-2 does not satisfy the quality requirement, the SIR target in the radio base stations 22-1 to 22-3 is updated. The radio base stations 22-1 to 22-3 control the transmission power of the mobile station 21 based on the updated SIR target. Therefore, there is no continuous state where the error information of the user signal relating to the high-speed data communication received by the radio base station 22-2 does not satisfy the quality requirement.

The process of controlling the transmission power of the radio signal transmitted by the mobile station 21 is explained in detail below. The radio base stations 22-1 to 22-3 transmit a signal requesting an increase in transmission power or a signal indicating a specific transmission power to the mobile station 21 if the SIR calculated based on the signal received from the mobile station 21 falls below the SIR target. Also, if the SIR calculated based on the signal received from the mobile station 21 rises above the SIR target, the radio base stations 22-1 to 22-3 transmit a signal requesting a reduction in transmission power or a signal indicating a specific transmission power to the mobile station 21.

The mobile station 21 controls the transmission power based on the transmission power control signal received from the radio base stations 22-1 to 22-3. At this time, the mobile station 21 controls the transmission power according to a certain rule based on a plurality of transmission power control signals received from the radio base stations 22-1 to 22-3. The specific rule may be, for example, the following rule. If all the received transmit power control signals indicate an increase in transmit power, the mobile station 21 increases the transmit power by a certain percentage. If any of the received transmit power control signals indicates a decrease in transmit power, mobile station 21 decreases the transmit power by a certain percentage. In addition, the mobile station 21 may consider the plurality of transmission power control signals received during the handover procedure to be identical. In this case, the mobile station 21 combines the received plurality of transmission power control signals into one signal. When the combined transmission power control signal indicates an increase in transmission power, the mobile station 21 increases the transmission power by a certain percentage, and when the combined transmission power control signal indicates a decrease in transmission power, the mobile station 21 decreases the transmission power by a certain percentage. Further, the mobile station 21 may give priority to the transmission power control signal from the radio base station that performs high-speed data communication. In this case, for example, the mobile station 21 controls the transmission power based on a transmission power control signal from a radio base station that performs high-speed data communication.

The procedure for controlling the transmit power described in 3GPP TS 25.214v5.3.0 may also be applied to embodiments of the present invention.

In this embodiment, when high-speed data communication is performed, since only one wireless base station performs high-speed data communication, the SIR target is generated based on only one of the signals 111 to 11n from the circuit processors 111 to 11 n. The number of signals based on which the SIR target is generated among the signals 111 to 11n is not limited to only one. When a plurality of radio base stations perform high-speed data communication, the SIR target can be generated based on a plurality of signals involved in the high-speed data communication among the signals 111 to 11n, the number of which is smaller than that involved in the handover of the normal communication.

Other embodiments of the present invention will be explained with reference to fig. 6 and 7. The same operations as those in the above-described embodiment will be denoted by the same numerals.

In the mobile communication system according to the above-described embodiment of the present invention, the outer loop processor 14 in the radio base station controller 23 generates SIR targets of radio signals received by the radio base stations 22-1 to 22-3 and supplies the SIR targets to the allocation processor 13 to control the transmission power of the mobile station 21. However, in the present embodiment, referring to fig. 7, the outer loop processor 14 in the wireless base station controller 23 may generate and provide the allocation processor 13 with the other control signals 40 than the SIR target (S301, S302). The control signal 40 may be a command to change the modulation type (e.g., BPSK, QPSK, 16QAM, etc.) of the radio or user signals transmitted by the mobile station 21, the transmit power, the type of communication (e.g., from high speed data communication to conventional communication), and other quality targets (e.g., error rate targets, Eb/NO targets (where Eb is the energy or power density per user bit and NO is the interference and noise power density), etc.) of the bit rate (spreading factor).

The distribution processor 13 distributes the control signal 40 received from the outer loop processor 14 to the circuit processors 11-1 to 11-3 together with the user signal received from the mobile communication switching center 24 via the circuit 102 (S303). The circuit processors 11-1 to 11-3 transmit the received user signals and control signals 40 to the radio base stations 22-1 to 22-3, respectively (S304).

Referring to fig. 6, the wireless base stations 22-1 to 22-3 receive the user signals and the control signals 40 from the wireless base station controller 23 (S31). In the mobile communication system according to the foregoing embodiment of the present invention, the radio base stations 22-1 to 22-3 generate transmission power control signals for controlling the transmission power of radio signals transmitted by the mobile station 21. In the present embodiment, however, the radio base stations 22-1 to 22-3 may generate other control signals 50 than the transmission power control signal based on the control signal 40 received from the radio base station controller 23 (S32). The control signals 50 may command changes in the modulation type (e.g., BPSK, QPSK, 16QAM, etc.), transmission power, bit rate (spreading factor), and communication type (e.g., from high speed data communication to conventional communication) of the radio signals or user signals transmitted by the mobile station 21, etc. Also, the radio base stations 22-1 to 22-3 transmit the user signals and the generated control signal 50 to the mobile station 21 (S33).

The mobile station 21 receives the user signal and the control signal 50 from the radio base stations 22-1 to 22-3 (S34). In the mobile communication system according to the foregoing embodiment of the present invention, the mobile station 21 controls the transmission power of the radio signal to the radio base stations 22-1 to 22-3 based on the received transmission power control signal. However, in the present embodiment, the mobile station 21 may control the radio signal in other ways than controlling the transmission power of the radio signal (S35). The mobile station 21 may change the modulation type (e.g., BPSK, QPSK, 16QAM, etc.), transmission power, bit rate (spreading factor), and communication type (e.g., from high-speed data communication to conventional communication) of the transmitted radio signal or user signal, and the like.

In the present embodiment, when high-speed data communication is performed, since only one wireless base station performs high-speed data communication, the control signal 40 is generated based on only one of the signals 111 to 11n from the circuit processors 11-1 to 11-3. The number of signals based on which the control signal 40 is generated among the signals 111 to 11n is not limited to only one. When a plurality of radio base stations perform high-speed data communication, the control signal 40 may be generated based on a plurality of signals related to high-speed data communication among the signals 111 to 11n, the number of which is smaller than that of radio base stations related to handover of normal communication.

In the above-described embodiment of the present invention, the setting signal 130 is input from the central processor 15 within the wireless base station controller 23 to the outer loop processor 14. However, the setting signal 130 may be input from outside the wireless base station controller 23.

In the above embodiments, the user signal involved in the regular communication may be a Dedicated Physical Control Channel (DPCCH) in WCDMA. Also, the uplink user signal related to high speed data communication may be a high speed dedicated physical control channel (HS-DPCCH), and the downlink user signal may be DPCCH and a high speed shared control channel (HS-SCCH) in WCDMA.

A characteristic aspect of the present invention is that, when a mobile station transmits radio signals to a plurality of base stations, those base stations are controlled based on radio signals received by specific base stations among those base stations, regardless of whether high-speed data communication is performed. According to one embodiment of the invention, a control signal for controlling a base station is determined based on quality information on a radio signal received by the particular base station.

The present invention is also characterized in that when a mobile station transmits radio signals to a plurality of base stations, those base stations are controlled in different manners depending on whether or not high-speed data communication is performed. According to one embodiment of the invention, the base station is controlled based on radio signals relating to high speed data communication.

According to the invention, a cellular mobile communication system can be improved. Also, it is possible to maintain sufficient power required for signals transmitted by the mobile station relating to high-speed data communication, and it is possible to improve the transmission efficiency of high-speed data communication. Further, it is not necessary to set the power relating to high-speed data communication transmitted by the mobile station higher than that of conventional communication. Therefore, the amount of signal interference can be suppressed, and the communication capacity can be improved.

It will be clear to those skilled in the art that numerous variations of the details of the preferred embodiments of the invention described above are possible. The scope of the invention should be determined from the following claims.

Claims

1. A control system for controlling radio signal transmission of a mobile station for use in a wireless communication system, comprising:

a plurality of base stations that simultaneously communicate with a mobile station by receiving radio signals relating to a first communication type transmitted by the mobile station;

a specific base station that communicates with the mobile station by receiving a radio signal relating to a second communication type different from the first communication type;

a controller that receives signals from the plurality of base stations based on the radio signals relating to the first communication type and receives signals from the specific base station based on the radio signals relating to the second communication type, wherein

The controller transmits a first control signal to the plurality of base stations and the specific base station on the basis of the signal relating to the radio signal of the second communication type received from the specific base station, and the plurality of base stations and the specific base station control radio signal transmission of the mobile station based on the first control signal.

2. The control system of claim 1, wherein

The first communication type is adapted for voice communications and the second communication type is dedicated for packet access communications.

3. The control system of claim 1, wherein

The signal received by the controller from the specific base station includes quality information on a radio signal related to the second communication type received by the specific base station from the mobile station, the controller generating the first control signal based on the quality information.

4. The control system of claim 1, wherein

The controller generates, as the first control signal, a quality target of the radio signal received by the plurality of base stations communicating with the mobile station and the specific base station.

5. The control system of claim 1, wherein

The plurality of base stations and the specific base station receive the first control signal transmitted by the controller and transmit a second control signal to the mobile station based on the first control signal.

6. The control system of claim 5, wherein

The signal received by the controller from the specific base station includes quality information on a radio signal related to the second communication type received by the specific base station from the mobile station,

the first control signal is a quality target of radio signals received by the plurality of base stations from the mobile station and radio signals received by the specific base station from the mobile station,

the second control signal is a transmission power control signal for controlling transmission power of the radio signal transmitted by the mobile station.

7. The control system of claim 6, wherein

The transmit power control signal commands an increase or decrease in the transmit power of the radio signal transmitted by the mobile station.

8. A wireless communication system, comprising:

a mobile station that transmits radio signals relating to a first communication type and radio signals relating to a second communication type different from the first communication type;

a plurality of base stations that communicate with the mobile station by receiving the radio signals relating to the first communication type;

a specific base station that communicates with the mobile station by receiving the radio signal relating to the second communication type; and

9. A controller for a mobile station to communicate with a plurality of base stations simultaneously in a wireless communication system, comprising:

a receiver that receives a plurality of signals relating to a first communication type from a plurality of base stations, and receives a signal relating to a second communication type different from the first communication type from a specific base station; and

a transmitter coupled to the receiver, which transmits a control signal generated based on the signal related to the second communication type received by the receiver from the specific base station to the plurality of base stations and the specific base station, wherein the plurality of base stations and the specific base station control radio signal transmission of the mobile station based on the control signal.

10. A controller for a mobile station to communicate simultaneously with multiple base stations in a wireless communication system as set forth in claim 9, wherein

11. A controller for a mobile station to communicate simultaneously with multiple base stations in a wireless communication system as set forth in claim 9, wherein

The signal received by the receiver from the particular base station comprises quality information on radio signals received by the particular base station from the mobile station relating to the second communication type.

12. A controller for a mobile station to communicate simultaneously with multiple base stations in a wireless communication system as set forth in claim 11, wherein

The control signal is a quality target of radio signals received by the plurality of base stations from the mobile station and radio signals received by the specific base station from the mobile station.

13. A control method for a wireless communication system, comprising:

simultaneously communicating between a plurality of base stations and a mobile station by using radio signals relating to a first communication type;

communicating between a specific base station and the mobile station by using a radio signal relating to a second communication type different from the first communication type;

receiving signals from the plurality of base stations based on radio signals relating to the first communication type;

receiving a signal from the particular base station based on a radio signal relating to the second communication type;

transmitting a first control signal to the plurality of base stations and the specific base station on the basis of the reception signal based on the radio signal relating to the second communication type, and the plurality of base stations and the specific base station controlling radio signal transmission of the mobile station based on the first control signal.

14. The control method for the wireless communication system according to claim 13, further comprising:

receiving the first control signal; and

transmitting a second control signal to the mobile station based on the first control signal.

15. The control method for a wireless communication system according to claim 14, wherein

Based on the received signal relating to the radio signal of the second communication type, including quality information on the radio signal relating to the second communication type,

the first control signal is a quality target of a radio signal relating to the first communication type and a radio signal relating to the second communication type, and the second control signal is a transmission power control signal for controlling transmission power of the mobile station.

16. The control method for the wireless communication system as claimed in claim 15, wherein

The transmit power control signal commands an increase or decrease in the transmit power of the mobile station.