JPH11340910A - Transmission power control method, base station equipment, control station and mobile station for cellular system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable continuous communication by preventing communication interruption from being continued between a base station and a mobile station by updating transmission power at the base station so as to be close to prescribed reference power after the transmission power is increased or decreased. SOLUTION: When communication is started, the base station sets down transmission power P for the signal of a down line to an initial value P0. When the reception of a slot is made successful and a down control instruction in that slot instructs power increase, a transmission power control part decreases the transmission power of the down line just by ΔP. When the reception of the slot is failed, on the other hand, the transmission power control part 205 updates transmission power Pa into r(Pb-C)+C so that a value r(Pb-C), where a coefficient (r) is multiplied to a difference (Pb-C) between transmission power Pb before updating and predetermined reference power C, can be equal with a difference (Pa-C) between transmission power Pa after updating and predetermined reference power C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellular system in which a mobile station communicates via one or more base stations installed in a service area, and more particularly, to a transmission power control command transmitted by the mobile station. The present invention relates to a transmission power control method and a base station apparatus for a cellular system in which a base station controls transmission power according to the following.

[0002]

2. Description of the Related Art In a cellular system of a code division multiplex system, since a large number of lines use the same frequency, the received power (desired wave power) of a signal on one line interferes with another line. It becomes interference wave power. Therefore, in the uplink transmitted by the mobile station and received by the base station, when the desired signal power exceeds a predetermined value, the interference signal power increases and the channel capacity decreases. To prevent this, it is necessary to strictly control the transmission power of the mobile station. In uplink transmission power control, the base station measures a desired wave power, compares it with a control target value, and, if the desired wave power is large, transmits to the mobile station the uplink transmission power (hereinafter, “ An uplink control command for decreasing the uplink transmission power is transmitted. If the desired signal power is small, an uplink control command for increasing the uplink transmission power is transmitted to the mobile station. Then, the mobile station increases or decreases the uplink transmission power according to the uplink control command. Regarding this uplink transmission power control method, US Pat.
No. 056,109 (Gilhousen et al., "Method
and the apparatus for control transmission power in a CDMA cellular mobile telephone system. "). The transmission of the uplink control command in this transmission power control uses the downlink transmitted from the base station to the mobile station.

On the other hand, even in the downlink, a high line capacity is realized by performing transmission power control such that the ratio between the desired wave power and the interference wave power becomes a predetermined amount. More specifically, in downlink transmission power control, a mobile station measures downlink reception quality, compares it with a control target value,
When the reception quality is higher than the control target value, the base station transmits a downlink control command to decrease the downlink transmission power (hereinafter also referred to as “downlink transmission power”), and the reception quality is higher than the control target value. If it is also lower, a downlink control command to increase the downlink transmission power is transmitted to the base station. Then, the base station increases or decreases the downlink transmission power according to the downlink control command.

[0004] However, in this method, when the propagation loss from the mobile station to the base station increases rapidly with the movement of the location of the mobile station, the base station cannot receive the downlink control command from the mobile station. At the same time, the mobile station may not be able to receive the uplink control command from the base station. At this time, in the conventional method in which the base station controls the downlink transmission power only by the downlink control command from the mobile station, if the propagation loss continues to increase, the base station issues the downlink control command from the mobile station. During reception, the base station does not increase the downlink transmission power, so that the mobile station cannot receive the uplink control command from the base station, and the uplink transmission power of the uplink signal can be increased. In other words, a problem that communication between the base station and the mobile station is interrupted continues.

[0005] In general, a part of user information such as voice and data in a signal received by a base station is corrected so that error correction can be performed even if a reception error occurs instantaneously. In addition, a relatively long amount of information is collectively encoded, and a relatively long amount of time is used to collectively decode a long amount of information during decoding.

However, when the mobile station moves at high speed and performs high-speed transmission power control to keep the reception quality constant by following fast fading fluctuations of the propagation path, even if the user information is accurate. Even if it can be decoded, the determination of the control instruction needs to be performed instantaneously, so that the determination of the control instruction cannot obtain an effect such as error correction.
Relatively often wrong.

[0007] Such a determination error of the control instruction occurs in relation to an increase or decrease in the propagation loss, and therefore, it is relatively likely to occur continuously. If the determination error of the control command continues, the base station cannot control the downlink transmission power of the downlink signal according to the downlink control command from the mobile station, and the mobile station cannot accurately receive the downlink signal. It is possible that On the other hand, in this state, the mobile station cannot receive the uplink control command from the base station included in the downlink signal, and thus may not be able to control the uplink transmission power of the uplink signal. At this time, the base station may not only frequently make a determination error of the downlink control command among the uplink signals, but also may not be able to receive user information accurately. In such a case,
There is a problem that communication between the base station and the mobile station is interrupted.

In a cellular system, there is a technique called soft handover in which, when a mobile station moves between cells, a line is switched between cells while simultaneously setting a plurality of base stations near the boundary. This technology is an important technology particularly in a cellular system employing a code division multiplexing system. The soft handover is described in US Pat. No. 5,102,501 (Gi
lhousen et al., "Method and system for providing a
soft handoff in communications in a CDMAcellular
telephone system. ").

When performing uplink transmission power control during the execution of such soft handover, a plurality of base stations measure the desired wave power of the mobile station, and each base station independently controls the uplink transmission power. An uplink control command is transmitted to the mobile station.
Then, the mobile station receives each uplink control command and, when receiving a different uplink control command, preferentially follows the command to reduce the uplink transmission power. This method is described in the literature (TIA /
EIA Interim Standard, Mobile Station-Base Station
Compatibility Standard for Dual-Mode Wideband Spre
ad Spectrum Cellular System, TIA / EIA / IS-95-A, Tele
communicationIndustry Association, May 1995, 6.6.
6.2.7.2 Reverse Traffic Channel Power Control Duri
ng Soft Handoff). In this way, when the uplink control command differs between base stations, by preferentially following the command to reduce the uplink transmission power, it is possible to prevent the desired wave power from exceeding the control target value in any base station, High line capacity is realized in the uplink.
Therefore, in this method, it is important for the mobile station to be able to receive the uplink control commands from all the base stations that have the possibility of minimizing the uplink propagation loss.

[0010] It is important that the transmission power control of the downlink during execution of the soft handover is performed so that the downlink control commands of all the mobile stations, which can minimize the propagation loss of the uplink, can be received by the base station. is there.

For this reason, a method of controlling the transmission power of the downlink so that the desired wave power from each base station becomes equal in the mobile station can be considered. However, in this method, since the base station having a large propagation loss to the mobile station sets the downlink transmission power to that extent, the interference wave power increases and the downlink capacity decreases. As a method of suppressing a decrease in downlink capacity, there is a method of controlling the downlink transmission power of each base station to be equal to each other. This method is described in the literature (Andersson, "Tuning two macro diversityperforma
nce in a DS-CDMA system. "Proc. IEEE 44th Vehicula
r Technology Conference, pp. 41-45, June 1994).

In this method, the received power of the uplink control command from the base station having a small propagation loss to the mobile station is larger than the received power of the uplink control command from the base station having a large propagation loss, and the difference is large. At times, the probability of failing to receive an uplink control command from a base station having a large propagation loss increases. In such a case, the transmission power of the uplink is not much of a problem because it is mainly controlled by an uplink control command from a base station having a small propagation loss. On the other hand, when the difference in propagation loss is small, it is important to control the uplink transmission power according to both base stations. In such a case, since each uplink control command can be received with substantially equal power, the probability that both uplink control commands can be accurately received increases. Therefore, it is possible to receive all the uplink control commands from the base station that may minimize the uplink transmission loss for uplink transmission power control.

Further, during execution of the soft handover, when the magnitude of the propagation loss from the mobile station to each base station is switched at a high speed due to fading fluctuation or the like, the base station for transmitting to the mobile station is Even if the switching is not performed at a high speed, the base station with the minimum propagation loss is transmitting at any moment.
At this time, if the downlink transmission powers of the base stations are not equal to each other, when the base station that minimizes the propagation loss switches,
Since the reception quality increases or decreases, the reception quality tends to deteriorate. However, if the downlink transmission powers of the respective base stations are equal to each other, the reception quality is further improved by the diversity effect that the reception quality is kept almost constant even if the base station with the minimum propagation loss is switched. You can also.

In such downlink transmission power control,
The mobile station measures the downlink reception quality, compares it with the control target value, and if the reception quality is higher than the control target value, transmits a downlink control command to the base station to reduce the downlink transmission power. If the reception quality is lower than the control target value, the base station transmits a downlink control command to increase the downlink transmission power to the base station. During execution of the soft handover, a plurality of base stations receive a downlink control command transmitted by the mobile station. Then, each base station performs control while increasing or decreasing the downlink transmission power in the same manner according to the downlink control command. Therefore, if the initial values of the downlink transmission powers of the respective base stations are equal to each other, the increase or decrease is repeated in the same manner.
The downlink transmission power is controlled while maintaining the same state.

However, in this method, the base station having the smallest propagation loss to the mobile station can receive the downlink control command from the mobile station almost exactly, but the base station having the large propagation loss from the mobile station has the downlink. Since the received power of the control command is small, the reception of the downlink control command from the mobile station often fails. Therefore, the downlink transmission power of each base station cannot be maintained equal to each other.

At this time, the downlink transmission power of the base station having a large propagation loss from the mobile station becomes smaller than the downlink transmission power of the base station having the smallest propagation loss from the mobile station due to the failure to receive the downlink control command. In such a case, a reception error is likely to occur in an uplink control command for uplink transmission power control transmitted by a base station having a large propagation loss from the mobile station. As described above, in uplink transmission power control,
Since it is important for the mobile station to be able to receive the uplink control commands from all the base stations that may minimize the uplink propagation loss, such uplink control command reception errors may cause the uplink channel capacity to be reduced. There is a problem that it decreases. In addition, there is also a problem that the diversity effect due to the above-described transmission of a plurality of base stations with the same power is reduced, and the reception quality is likely to deteriorate.

On the other hand, the downlink transmission power of the base station having a large propagation loss from the mobile station is larger than the downlink transmission power of the base station having the smallest propagation loss from the mobile station due to the failure to receive the uplink control command. In such a case, the downlink transmission power of the downlink is controlled so that the desired wave power from each base station becomes equal in the mobile station.As in the case of the method described above, the propagation loss to the mobile station is reduced. Since a large base station sets a large downlink transmission power, there arises a problem that interference wave power increases and downlink capacity decreases.

In order to prevent a base station having a large propagation loss from a mobile station from failing to receive a downlink control command from a mobile station due to a large propagation loss, Japanese Patent Laid-Open No. 9-31260 has been proposed.
As described in Japanese Patent Application Publication No. 9-209, there is a method of independently controlling downlink transmission power in each base station, ignoring downlink control commands having low reception quality and low reliability. However, in that method, each base station does not transmit with the same power, and the above-mentioned problem cannot be solved. Japanese Patent Application Laid-Open No. 9-312609 discloses that a control signal transmitted from a mobile station is collected at a combining station (control station) via a base station, and the downlink signal power of each base station is controlled based on the collected information. A method is also described. However, when high-speed transmission power control is to be realized by this method, there is a problem that the amount of control signal transmission between the base station and a control station connected to each base station increases. Further, if the control signal transmission amount is to be suppressed, there is a problem that the delay becomes large and high-speed transmission power control cannot be realized.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to solve the problem when the propagation loss between the base station and the mobile station increases rapidly, or when the base station transmits the signal from the mobile station. Transmission power control of a cellular system that enables continuous communication without interruption of communication between a base station and a mobile station even when errors in the determination of a downlink control command continue. It is to provide a method.

Another object of the present invention is to solve the above-mentioned problems and to provide a method for performing a soft handover without significantly increasing the amount of control signal transmission between a base station and a control station. In each base station, even if an error occurs in receiving a downlink control command for downlink transmission power control from the mobile station, each base station can transmit with substantially equal power to each other, and An object of the present invention is to provide a transmission power control method for a cellular system capable of obtaining a high capacity in a downlink.

[0021]

According to the present invention, a mobile station comprises one mobile station.
While setting up a line with one or more base stations,
Each time the base station receives a control command from the mobile station, it increases or decreases transmission power according to the control command, and the transmission power of the base station after the increase or decrease approaches a predetermined reference power. The transmission power control operation for updating the transmission power is repeated.

To this end, while the mobile station is setting up a line with one or more base stations, the base station receives a control command from the mobile station each time it receives a control command. The transmission power P is increased or decreased, and the difference (Pa−C) between the transmission power Pa of the base station after the increase or decrease and the predetermined reference power C is determined by the transmission power Pb before the update and the predetermined reference power C {Pa = r (Pb-C) + C}, and the transmission power P is updated so that the difference (Pb−C) becomes r times (0 ≦ r <).

The value of r is a value obtained by multiplying the difference between the maximum value and the minimum value of the control range of the transmission power P by (1-r) to increase or decrease the transmission power according to the control command. It is set to be smaller than the power change.

More specifically, the mobile station includes a plurality of cells, a plurality of base stations respectively installed in the plurality of cells, and a mobile station moving in each cell. In a transmission power control method of a cellular system for performing communication by setting a line between the mobile station and the plurality of base stations, the mobile station sets the line between the plurality of base stations. A first transmission power control operation of transmitting a control command of the transmission power of the base station to the base station and changing the transmission power according to the control command received by the base station receiving the control command is repeated. A second transmission power control operation in which the base station updates the transmission power so that the absolute value of the difference between the decibel value of the predetermined reference power and the decibel value of the transmission power decreases at a predetermined rate. Characterized by repetition .

In the transmission power control method for a cellular system according to the present invention, the reference power is a maximum transmission power of the transmission power.

In the present invention, while the mobile station is setting up a line with a plurality of base stations, the base station receives a control command from the mobile station every time it receives a control command. Increase or decrease the transmission power, reduce the difference in transmission power between a plurality of base stations after the increase or decrease, and set the transmission power so that the transmission power approaches a common reference power set among a plurality of base stations. Is repeated.

To this end, while the mobile station is setting up a line with a plurality of base stations, each of the plurality of base stations is:
Each time a control command is received from the mobile station, the transmission power P is increased or decreased in accordance with the control command, and the transmission power Pa of the base station after the increase or decrease is determined in common among a plurality of base stations. The difference (Pa−C) between the reference power C and the difference (Pb−C) between the transmission power Pb before the update and the reference power C is r
｛Pa = r (Pb−C) + so as to be twice (0 ≦ r <1)
C｝, the transmission power P is updated.

Further, according to the transmission power control method for a cellular system of the present invention, the product of the difference between the maximum value and the minimum value of the control range of the transmission power P and (1-r) is the transmission power according to the control command. R is set so as to be smaller than a change in transmission power when increasing or decreasing.

More specifically, the mobile station includes a plurality of cells, a plurality of base stations respectively arranged in the plurality of cells, and a mobile station moving in each cell, and the mobile station includes one or a plurality of base stations. In the transmission power control method of a cellular system for performing communication by setting a line between the mobile station and the plurality of base stations, the mobile station sets a line between the base station and the plurality of base stations. Transmitting a control command for transmission power of a base station to each of the first transmission power, wherein each of the plurality of base stations receives the control command and changes the transmission power according to the received control command. While repeating the control operation, the absolute value of the difference between the decibel value of the reference power and the decibel value of the transmission power determined in common among the plurality of base stations is reduced at a common rate among the plurality of base stations. So that each of the plurality of base stations There and repeating the second transmission power control operation for updating the transmission power.

In the transmission power control method for a cellular system according to the present invention, the reference power is a maximum transmission power of the transmission power.

In the transmission power control method for a cellular system according to the present invention, the reference power is an intermediate power between the decibel value of the maximum transmission power and the decibel value of the minimum transmission power.

Further, the transmission power control method for a cellular system according to the present invention is characterized in that the reference power is a minimum transmission power of the transmission power.

In the transmission power control method for a cellular system according to the present invention, each of the plurality of base stations calculates a statistical value of transmission power and notifies the control station of the statistical value. Using the statistic of, the reference value representing the reference power is calculated and notified to the plurality of base stations, and the plurality of base stations calculate the reference power represented by the notified reference value. It is characterized by using.

The transmission power control method for a cellular system according to the present invention is characterized in that a maximum statistic value among the statistic values is used as the reference value.

Further, in the transmission power control method for a cellular system according to the present invention, the control station determines the common ratio according to a mutual difference between the statistical values of the plurality of base stations. .

[0036] In the transmission power control method for a cellular system according to the present invention, the control station updates the transmission power at the common rate in accordance with a difference between the statistical values of the plurality of base stations. Is determined.

Further, according to the transmission power control method for a cellular system of the present invention, the mobile station has information on the accumulated control value of the transmission power in the base station, and transmits the accumulated control value to the base station transmission power control command. Update every transmission, at a time interval longer than the repetition time interval of the transmission power update operation, transmit to the plurality of base stations, the plurality of base stations, using the received cumulative control value , Wherein the reference power is determined and used.

[0038] The transmission power control method for a cellular system according to the present invention is characterized in that the transmission power is updated by the plurality of base stations simultaneously.

The base station apparatus of the cellular system according to the present invention comprises:
While the mobile station is setting up a line with one or more base stations, each time a control command is received from the mobile station,
The transmission power is increased or decreased according to the control command, and the transmission power is updated such that the transmission power of the base station after the increase or decrease approaches a predetermined reference power.

To this end, while the mobile station is setting up a line with one or more base stations, the base station receives a control command from the mobile station every time the mobile station receives the control command. The transmission power P is increased or decreased, and the difference (Pa−C) between the transmission power Pa of the base station after the increase or decrease and a predetermined reference power C is determined by comparing the transmission power Pb before the update with the predetermined reference power C R times the difference (Pb−C) from C (0 ≦ r <
{Pa = r (Pb−C) + C} and the transmission power P is updated so as to satisfy 1).

The value of r is a value obtained by multiplying the difference between the maximum value and the minimum value of the control range of the transmission power P by (1-r) to increase or decrease the transmission power according to the control command. It is set to be smaller than the power change.

More specifically, the mobile station includes a plurality of cells, a plurality of base stations respectively arranged in the plurality of cells, and a mobile station moving in each cell, and the mobile station includes one or a plurality of base stations. In a base station apparatus of a cellular system that performs communication by setting a line between the mobile station and the base station, the mobile station is connected to the base station while the mobile station sets a line with one or more base stations. A first transmission for transmitting a control command of the transmission power of the base station to the first base station and repeating the first transmission power control operation in which the base station receives the control command and changes the transmission power according to the received control command. Power control means, and a second transmission power at which the base station updates the transmission power so that the absolute value of the difference between the decibel value of the predetermined reference power and the decibel value of the transmission power is reduced at a predetermined rate. The second transmission power that repeats the control operation Characterized by a control unit.

Further, the base station apparatus of the cellular system according to the present invention is characterized in that the reference power is the maximum transmission power of the transmission power.

[0044]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The transmission power control method for a cellular system according to the first embodiment is carried out in a cellular system having the configuration shown in FIG. In the cellular system of FIG. 1, the service area is divided into first and second cells 11 and 12, and the first and second cells have first and second base stations 21 and 22, respectively. Placed and the first
And second mobile stations 61 and 62. The first and second base stations 21 and 22 are each connected to a control station 71, and the control station 71 is further connected to a communication network (not shown) including other control stations. Although not shown, the cellular system includes a number of other base stations, and a number of mobile stations exist in each cell.

The first and second base stations 21 and 22 transmit the first and second pilot signals 31 and 32 at a constant transmission power, respectively. Each of the mobile stations 61 and 62 includes a measuring device for measuring the power of the pilot signal, as will be described later.
1 and 32 are measured respectively. The mobile station switches the pilot signal measuring device in units of short time slots as shown in FIG. 2, and measures each of the pilot signals of the plurality of base stations once for each frame. In the example of FIG. 2, since one frame has six slots, pilot signals from a maximum of six base stations can be measured.

When the mobile station moves, the instantaneous value of the received power fluctuates in a short cycle with time as shown in FIG. Therefore, the mobile station measures the received power for a number of frames corresponding to a sufficiently long time with respect to the period of the instantaneous value fluctuation of the received power when the mobile station moves to obtain the median value, and Find the median of the measured values in the slot.

When performing communication, a line is set between the base station and the base station having the largest central value of the received power of the pilot signal to start communication. During communication, the received power of the pilot signal may fluctuate with the movement of the mobile station, but if the base station having the largest median value of the received power of the pilot signal changes, the base station for setting the line is changed. Update the station.

In the first mobile station 61, assuming that the received power of the first pilot signal 31 is maximum, for example,
The mobile station 61 sets a line with the first base station 21. The first downlink signal 41 is a signal transmitted from the first base station 21 to the first mobile station 61, and the first uplink signal 51 is transmitted from the first mobile station 61 to the first mobile station 61. This signal is transmitted to the base station 21. On the other hand, in the second mobile station 62, the received power of the first pilot signal 31 becomes maximum, and a line is set up with the first base station 21. At this time, the second mobile station 62 communicates with the first base station 21 using the second downlink signal 42 and the second uplink signal 52.

First and second downlink signals 41, 4
2 and the first and second uplink signals 51 and 52 are each composed of a repetition of a frame of a fixed length as shown in FIG. 2, and each frame is composed of a plurality of slots of a shorter time. Have been. The downlink signal slot includes a transmission signal control instruction for the uplink signal, and the uplink signal slot includes a transmission signal control instruction for the downlink signal. It is included.

FIG. 4 shows the first and second base stations 21 and 22.
1 shows the configuration of the base station apparatus. The base station device has an antenna 2
01, transmission / reception duplexer 202, reception circuit 203, SIR measurement section 204, transmission power control section 205, transmission circuit 206,
Receiver circuit output terminal 207 and transmitter circuit input terminal 208
It is composed of

SIR measuring section 204 is a measuring instrument for measuring the ratio (SIR) of the desired signal power to the interference signal power on the uplink, and thereby, every time a slot transmitted by the mobile station is received, its uplink is measured. Measure SIR.

FIG. 5 shows the first and second mobile stations 62, 62.
1 shows a configuration of a mobile station device. The mobile station device has an antenna 6
01, transmission / reception duplexer 602, reception circuit 603, SIR measurement 604, transmission power control section 605, transmission circuit 606, reception circuit output terminal 607, transmission circuit input terminal 608, pilot signal power measurement device 612, and pilot signal terminal 613. It is configured.

The SIR measurement 604 is a measuring device for measuring the SIR of the downlink, and measures the downlink SIR each time a slot transmitted by the base station is received.

First, downlink transmission power control will be described.

In the mobile station, the downlink signal transmitted from the base station is received by the receiving circuit 603 via the antenna 601 and the duplexer 602. Each time the receiving circuit 603 receives a slot of a downlink signal,
The SIR measurement section 604 measures the downlink SIR of the downlink signal and obtains a measured downlink SIR value representing the downlink SIR. S
The IR measurement unit 604 calculates the measured downlink SIR value and the target downlink SI
Compare with R value. The measured downlink SIR value is the target downlink SIR
When the value is smaller than the value, SIR measurement section 604 outputs a downlink control command instructing an increase in downlink transmission power. When the measured downlink SIR value is larger than the target downlink SIR value, SIR measurement section 604 outputs a downlink control command instructing a decrease in downlink transmission power. The downlink control command is supplied to the transmission circuit 606. The transmission circuit 606 transmits a downlink signal including a downlink control command for each slot to the base station via the duplexer 602 and the antenna 601.

In the base station, the uplink signal transmitted from the mobile station is received by receiving circuit 203 via antenna 201 and duplexer 202. Each time the receiving circuit 203 receives an uplink signal slot,
Receiving circuit 203 sends a downlink control command included in the slot to transmission power control section 205. Transmission power control section 205
Calculates the downlink transmission power for the downlink signal for each slot using the downlink control command sent from the reception circuit 203, and sends a downlink transmission power control signal indicating the downlink transmission power to the transmission circuit 206. . In response to the downlink transmission power control signal, the transmission circuit 206 sets the downlink transmission power for the downlink signal to the value indicated by the downlink transmission power control signal. Then, the base station transmits the downlink signal generated by the transmitting circuit 206 to one or more mobile stations via the duplexer 202 and the antenna 201.

Next, uplink transmission power control will be described.

In the base station, the uplink signal transmitted from the mobile station is received by receiving circuit 203 via antenna 201 and duplexer 202. Each time the receiving circuit 203 receives an uplink signal slot,
The SIR measurement unit 24 measures the uplink SIR of the uplink signal and obtains a measured uplink SIR value representing the uplink SIR. SI
The R measurement unit 204 calculates the measured uplink SIR value and the target uplink SIR
Compare with value. When the measured uplink SIR value is smaller than the target uplink SIR value, SIR measurement section 204 outputs an uplink control command instructing an increase in uplink transmission power. Measurement up S
When the IR value is larger than the target uplink SIR value, SIR measurement section 204 outputs an uplink control command instructing a decrease in uplink transmission power. The uplink control command is supplied to the transmission circuit 206. The transmission circuit 206 transmits to one or more mobile stations via the duplexer 202 and the antenna 201,
An uplink signal including an uplink control command is transmitted for each slot.

In the mobile station, a downlink signal transmitted from the base station is received by the receiving circuit 603 via the antenna 601 and the duplexer 602. Each time the receiving circuit 603 receives a slot of a downlink signal,
Receiving circuit 603 sends an uplink control command included in the slot to transmission power control section 605. Transmission power control section 605
Calculates the uplink transmission power for the uplink signal for each slot using the uplink control command sent from the reception circuit 603, and sends an uplink transmission power control signal indicating the uplink transmission power to the transmission circuit 606. . In response to the uplink transmission power control signal, transmission circuit 606 sets the uplink transmission power for the uplink signal to the value indicated by the uplink transmission power control signal. Then, the mobile station transmits the uplink signal generated by transmission circuit 606 to the base station via duplexer 602 and antenna 601.

Referring to FIG. 6 in addition to FIG. 1 and FIG. 4, transmission power control for downlink signals by transmission power control section 205 of the base station will be described. Here, it is assumed that the downlink transmission power P is represented by a decibel value.

When starting communication, the base station sets downlink transmission power P for downlink signals to an initial value P0 (step S101). The initial value P0 is an arbitrary value within the control range of the transmission power. In step S102, the transmission power control unit 205 determines that the reception of the slot has been successful if the uplink SIR value of the slot is equal to or greater than a predetermined value each time the uplink signal transmitted by the mobile station is received. If the uplink SIR value of the slot is less than the predetermined value, it is determined that the reception of the slot has failed. In step S102, if the transmission power control unit 205 succeeds in receiving the slot, if the downlink control command in the slot indicates an increase in power (step S10).
3), the transmission power of the downlink is increased by a predetermined value ΔP (S104), and when the power reduction is instructed (NO in step S103), the transmission power of the downlink is increased by a predetermined value ΔP. It is decreased (S105). On the other hand, if the slot reception has failed in step S102, the process proceeds to step S106.

Next, in step S106, transmission power control section 205 multiplies a value r obtained by multiplying a difference (Pb-C) between transmission power Pb before update and predetermined reference power C by coefficient r.
The transmission power Pa is updated to r (Pb-C) + C so that (Pb-C) becomes equal to the difference (Pa-C) between the updated transmission power Pa and the predetermined reference power C. If the transmission power P is larger than the maximum power Pmax (step S
107), the transmission power P is set to the maximum power Pmax (S108), and if the transmission power P is smaller than the minimum power Pmin (YES in step S109), the transmission power P
Is set to the minimum power Pmin (S110). And it repeats from step S102 again.

The predetermined reference power C is set so that when the base station makes the downlink transmission power P of the downlink signal equal to the reference power C, most mobile stations in the cell can receive the downlink signal. , Within the control range of the transmission power P is set to a relatively high value. In this embodiment, the downlink transmission power P is set as the maximum transmission power Pmax. The coefficient r is set in a range of 0 or more and less than 1. However, in order to be able to increase or decrease the downlink transmission power P by a downlink control command from the mobile station, increase the downlink transmission power P in step S106. Is set to be smaller than the increase / decrease ΔP of the transmission power in steps S104 and S105. Therefore, {r (P−C) + C} −P, which is the increment of the downlink transmission power P in step S106, that is,
(1-r) (CP) corresponds to steps S104 and S105.
The value of the coefficient r is set so as to be smaller than the increase / decrease amount ΔP of the downlink transmission power P in the above. Further, the setting range of the coefficient r is 1−ΔP / (Pmax−P) <r <1. Here, for example, the difference between Pmax and Pmin is 10 dB, and ΔP is 1 d
If B, 0.9 <r <1. However, if the coefficient r is set to a value very close to 1, step S1
It is considered that the coefficient r should be set to about 0.95 because the effect obtained by the parameter 06 becomes smaller.

According to this method, when the propagation loss from the mobile station to the base station suddenly increases with the movement of the location of the mobile station, the state in which the communication between the base station and the mobile station is interrupted. Communication can be continued without continuing. Considering a state where the propagation loss from the mobile station to the base station has increased rapidly, the base station fails to receive the uplink signal and cannot receive the control command included in the slot, but the base station has When the reception of the slot of the line signal fails, the downlink transmission power P is brought closer to the predetermined reference power C. Therefore, if the reception failure of the slot continues, the value becomes close to the reference power C. Since the reference power C is set to a relatively high transmission power value in the control range of the downlink transmission power P, when the downlink transmission power P approaches the reference power C, the mobile station transmits the signal to the base station. It becomes possible to receive downlink signals. When the base station fails to receive the uplink signal, the base station returns the SI of the uplink signal.
Since R is small, the mobile station notifies the mobile station of an uplink control command to increase the transmission power of the mobile station. However, when the mobile station can receive a downlink signal transmitted by the base station, the mobile station transmits the uplink signal. Since the transmission power of the uplink signal is increased according to the control command, the base station can receive the uplink signal. In this way, communication between the base station and the mobile station can be performed again in both directions, and communication can be continued without interrupting the communication between the base station and the mobile station. it can.

In step S106, since the downlink transmission power Pa is updated to r (Pb-C) + C, (PC) becomes r times for each time unit of the slot. Assuming that P 1, after the update of step S 106 is repeated n times in a state where the downlink transmission power P is not changed in steps S 104 and S 105, (P−
C) is a value obtained by multiplying (P1-C) by the nth power of r. Since the coefficient r is less than 1, the n-th power of the coefficient r gradually approaches zero. Accordingly, the downlink transmission power P approaches the reference power C by step S106.

In the base station, the determination error of the downlink control command was continuously made, so that the downlink transmission power of the downlink signal could not be correctly controlled, and the mobile station could not receive the downlink signal accurately. Consider the case. In such a situation, the error determination of the downlink control command is random,
In general, the probability of a downlink control command instructing an increase in downlink transmission power is substantially equal to the probability of a downlink control command instructing a decrease. Therefore, in steps S104 and S105, the downlink transmission power P does not increase or decrease on average. However, according to this method, even in such a situation, the downlink transmission power P approaches the reference power C, and the mobile station can receive the downlink signal transmitted by the base station. As a result, as in the case where the propagation loss from the mobile station to the base station sharply increases, two-way communication can be performed again between the base station and the mobile station, and between the base station and the mobile station. The communication can be continued without continuing the state where the communication is interrupted.

In this embodiment, the mobile station sets up a line with only one base station, but the mobile station implements a soft handover in which a line is set up with two or more base stations. Even in this case, since each of the base stations controls the downlink transmission power in exactly the same way as in this embodiment, even if the propagation loss from the mobile station to the base station increases rapidly, communication can be continued in exactly the same manner. .

Next, another embodiment of the present invention will be described with reference to the drawings.

The transmission power control method for a cellular system according to the second embodiment is implemented in a cellular system having the configuration shown in FIG. In the cellular system of FIG. 7, the service area is divided into first and second cells 11 and 12, and the first and second cells include first and second base stations 21A and 22A, respectively. While being placed,
There are first and second mobile stations 61A, 62A. The first and second base stations 21A and 22A are each connected to a control station 71A, and the control station 71A is further connected to a communication network (not shown) including other control stations. Although not shown, the cellular system includes a number of other base stations, and a number of mobile stations exist in each cell.

First and second base stations 21A, 22A
Transmits the first and second pilot signals 31, 32 at a constant transmission power, respectively. Each mobile station 61A, 62
A includes a measuring device for measuring the power of the pilot signal, as described later, and measures the received power of the first and second pilot signals 31 and 32, respectively. The mobile station switches the pilot signal measuring device in units of short time slots as shown in FIG. 2, and measures each of the pilot signals of the plurality of base stations once for each frame. In the example of FIG. 2, since one frame has six slots,
Pilot signals from up to six base stations can be measured.

When the mobile station moves, the instantaneous value of the received power fluctuates in a short cycle with time as shown in FIG. Therefore, the mobile station measures the received power for a number of frames corresponding to a sufficiently long time with respect to the period of the instantaneous value fluctuation of the received power when the mobile station moves to obtain the median value, and Find the median of the measured values in the slot.

At the time of communication, a line is set up with a base station having the largest central value of the received power of the pilot signal (hereinafter, referred to as "main base station") to start communication. If there is a base station in which the median pilot signal received power is greater than the median pilot signal received power of the primary base station by a predetermined handover threshold, the base station (Hereinafter referred to as “auxiliary base station”). During communication, the received power of the pilot signal may fluctuate with the movement of the mobile station, but when the base station having the largest median value of the received power of the pilot signal changes,
When the auxiliary base station no longer satisfies the condition, and when another base station satisfies the condition of the auxiliary base station, the main base station and the auxiliary base station are updated.

Here, in the first mobile station 61A, for example, the received power of the first pilot signal 31 is the maximum, and the difference between the received power of the second pilot signal 32 and the received power of the first pilot signal 31 is handed over. It is assumed that it is within the threshold value. In such a case, the first base station 21A becomes the main base station, and the second base station 22A becomes the auxiliary base station. First
Of the main downlink signal and the first auxiliary downlink signal 41b are signals transmitted from the first base station 21A and the second base station 22A to the first mobile station 61A, respectively. The uplink signal 51 is a signal transmitted from the first mobile station 61A to the first and second base stations 21A and 22A.

On the other hand, in the second mobile station 62A, the reception power of the first pilot signal 31 becomes maximum, and the first base station 21 becomes the main base station. First pilot signal 31
It is assumed that the difference between the received power of the second pilot signal 32 and the received power of the second pilot signal 32 is larger than the handover threshold, and that there is no auxiliary base station. At this time, the second mobile station 62A uses the second downlink signal 42 and the second uplink signal 52 to perform the first mobile station 62A.
Communication with the base station 21A.

FIG. 8 shows the first and second base stations 21A, 21A and 2A.
2 shows a configuration of a 2A base station apparatus. The base station apparatus includes an antenna 201, a duplexer 202, a receiving circuit 203, an SI
R measurement unit 204, transmission power control unit 205, transmission circuit 20
6, receiving circuit output terminal 207 and transmitting circuit input terminal 2
08, a timer 210 and a timer terminal 211 are provided. The timer 210 measures the passage of time.

FIG. 9 shows first and second mobile stations 62A and 62A.
2A shows a configuration of a mobile station apparatus. The mobile station device includes an antenna 601, a duplexer 602, a receiving circuit 603, an SI
R measurement 604, transmission power control section 605, transmission circuit 60
6, receiving circuit output terminal 607, transmitting circuit input terminal 60
8, a pilot signal power measuring device 612, and a pilot signal terminal 613, as well as a timer 610, a timer terminal 611, and a cumulative control value updating unit 614. Timer 610 measures the passage of time. The cumulative control value updating unit 614 updates the cumulative control value as described later.

Referring to FIG. 10, reception circuit 603 includes reception signal input terminal 603a and reception signal output terminal 603.
b, and the first to third base station signal receiving circuits 603-
1, 603-2, 603-3 and receiving base station control section 603
-4 and a combining unit 603-5. With such a configuration, the receiving circuit 603 can combine and receive the same signal transmitted from a plurality of base stations.

Referring to FIG. 11, control station 71A includes first and second base station connection input terminals 701, 70 connected to first and second base stations 21A, 22A, respectively.
2 and the first and second base stations 21A and 22A, respectively.
And second base station connection output terminals 70 connected to
3,704. The control station 71 </ b> A
5, a reference value calculator 706, and a notification transmitter 707.

Returning to FIG. 7, the operation of the cellular system shown in FIG. 7 will be described. As mentioned above, the first
The second base station 21A and the second base station 22A operate as a main base station and an auxiliary base station, respectively, with respect to the first mobile station 61A executing the soft handover. The first base station 21A and the second base station 22A
Of the first main downlink signal, which is the same information except for the uplink control command of the uplink transmission power, to the mobile station 61A.
a and the first auxiliary downlink signal 41b are transmitted. The first mobile station 61 </ b> A receives the first
Of the main downlink signal 41a and the signal 41b of the first auxiliary downlink are combined and received.
At 04, the downstream SIR is measured. Then, the SIR measurement section 604 compares the downlink measurement SIR value with the downlink target SIR value, and if the downlink measurement SIR value is smaller than the downlink target SIR value, sets the downlink control command to increase power, and sets the downlink measurement SIR If the value is greater than the downlink target SIR value,
The downlink control command is set to power reduction. First mobile station 61A
Transmits the downlink control command to the first and second base stations 21
A, 22A is notified. Similarly, the second mobile station 6
1A notifies a downlink control command to the first base station 21A. Then, the first and second base stations 21A, 22A
Performs downlink transmission power control by following the downlink control command.

The base station during the soft handover controls the downlink transmission power using the reference power C which is commonly defined between the base stations. The reference power C can be determined by a common method such as a maximum value, a minimum value, or an intermediate value between the maximum value and the minimum value of the downlink transmission power per line of the base station. Therefore, when the maximum value and the minimum value of the downlink transmission power set for each base station are different, the reference power C may have a different value accordingly. However, in this embodiment, it is assumed that the control ranges of the downlink transmission power per line of all base stations are equal to each other, and the reference power C is also equal to each other.

On the other hand, in order to perform uplink transmission power control, first and second base stations 21A and 22A measure the uplink SIR for each slot, and if the uplink measured SIR value is smaller than the uplink target SIR value, The uplink control command is set to increase power, and if the uplink measurement SIR value is larger than the uplink target SIR value, the uplink control command is set to decrease power and the mobile station is notified of the uplink control command. The second mobile station 62A controls the uplink transmission power according to the uplink control command transmitted by the first base station 21A that has set up the channel. On the other hand, the first mobile station 61A receives the uplink control commands transmitted by the two base stations, since the first mobile station 61A has set up the channel simultaneously with the first and second base stations 21A and 22A. At this time,
When the contents of the two uplink control commands are different, the first mobile station 61A controls the uplink transmission power according to the uplink control command for reducing the uplink transmission power.

Referring to FIG. 12 in addition to FIGS. 7 and 8, transmission power control for the downlink in the cellular system shown in FIG. 7 will be described. FIG. 12 is a flow chart in which the base station receives a downlink control command from the mobile station and determines downlink downlink transmission power during execution of soft handover. Here, it is assumed that the downlink transmission power P is represented by a decibel value.

When starting a soft handover with a mobile station, the base station is a main base station that has been transmitting to the mobile station for a long time (step S2).
(01: NO), the downlink transmission power P is kept at the value immediately before the transmission power for the mobile station, and the base station is an auxiliary base station that has newly started transmission to the mobile station (step S201). YES), the downlink transmission power P is set to the initial value P0 (step S202). Further, the measurement time Tb of the timer 210 is initialized to 0 (Step S)
203). Here, the main base station and the auxiliary base station are notified of the frame number via soft handover from the control station 71A, and initialize the measurement time Tb when transmitting the frame, so that the main base station and the auxiliary base station can The timer 210 can be initialized. The initial value P0 is an arbitrary value within the control range of the downlink transmission power. The downlink control command is notified from the mobile station at regular intervals, and is transmitted at step S20.
In 4, there is a newly notified downlink control command,
If the downlink control command indicates an increase in power,
The transmission power control unit 205 increases the downlink transmission power P by a predetermined value ΔP (steps S205 and S206),
When the downlink control command indicates power reduction, the transmission power control unit 205 sets the downlink transmission power P to a predetermined value Δ
It is decreased by P (steps S205, S207).

Next, in step S208, when the measured time Tb of the timer 210 has exceeded the time Tint, the transmission power control unit 205 determines whether the downlink transmission power P
The value r (Pb-C) obtained by multiplying the difference (Pb-C) between the b and the predetermined reference power C by the coefficient r is the difference (Pa) between the updated downlink transmission power Pa and the predetermined reference power C. The downlink transmission power P is updated to r (Pb−C) + C so as to be equal to −C) (step S209). In this embodiment, the time Tin
t and the coefficient r are predetermined constant values, and the coefficient r is a value of 0 or more and less than 1. Well, the reference power C is an intermediate power (Pma) between the maximum power Pmax and the minimum power Pmin of the downlink transmission power P.
x + Pmin) / 2.

If the updated transmission power P is equal to the maximum power Pma
x, the downlink transmission power P is set to the maximum power Pm
ax (step S211), and when the updated transmission power P is smaller than the minimum power Pmin, the downlink transmission power P is set to the minimum power Pmin (step S212). And
Repeat from step S203 again.

In this embodiment, one mobile station performs soft handover with two base stations. However, if one mobile station performs soft handover with three or more base stations, one mobile station performs one soft handover. Each time the number of base stations that perform soft handover increases, the process repeats from step S201 to align the measurement time Tb of the timer 210 between the base stations.

According to this method, when the soft handover is started, the initial values of the downlink transmission power of the main base station and the auxiliary base station are different, so that the downlink transmission power P1 of the main base station and the downlink transmission power of the auxiliary base station are different. Difference between power P2 and | P1
−P2 |. Also, if one or more base stations fail to receive the downlink control command, these downlink transmission powers P
The difference | P1−P2 | between 1 and P2 may increase. However, control of steps S204 to S207, that is,
In the part where the downlink transmission power is increased or decreased by the downlink control command from the mobile station, since each base station receives the same downlink control command notification, each base station fails to receive the downlink control command. Otherwise, the downlink transmission powers P1 and P2 are similarly increased or decreased, so that the difference | P1−P2 | between these downlink transmission powers P1 and P2 does not change.

On the other hand, each time the measurement time Tb of the timer 210, which is simultaneously initialized, elapses by the time Tint, the main base station and the auxiliary base station respectively transmit the downlink transmission powers P1 and P2 to r.
(P1−C) + C and r (P2−C) + C are updated at the same time, so the difference | P1−P2 |
Becomes r | P1−P2 |. As described above, the difference | P1−P2 | of the downlink transmission power becomes r times every time Tint. Since the coefficient r is smaller than 1, unless the downlink transmission power difference | P1−P2 | increases due to a reception error of a new downlink control command, the difference in the control amount decreases geometrically to 0. Converge. Further, even if the difference | P1−P2 | of the downlink transmission power increases due to the occurrence of a reception error of a new downlink control command, the difference | P1−P2 | can be reduced.
Therefore, even if the reception of the downlink control command fails, the transmission power Pi (i = 1, 2) of the downlink is maintained between the base stations without exchanging information regarding the downlink transmission power between the base stations. The values can be adjusted to be substantially equal to each other.

That is, after the downlink transmission power is increased or decreased by the control in steps S204 to S207, the difference in the downlink transmission power of a plurality of base stations is reduced by the control in steps S208 to S213. Thus, the downlink transmission power is updated so as to approach the reference power C which is commonly determined among a plurality of base stations.

As described above, while the mobile station is executing the soft handover, each base station transmits an uplink control command for uplink transmission power control to the mobile station with substantially equal power between the base stations. Therefore, when the propagation loss from each base station to the mobile station is almost the same and there is a possibility that the propagation loss of the uplink is minimized in any of the base stations, the mobile station can receive all the uplink control commands. . Therefore, the mobile station can control the uplink transmission power so that the desired wave power does not become excessive for any of the base stations.

Further, the downlink transmission power of the base station is equal to the time Tin.
At this time, control is performed independently of the downlink control command, so at this time, even if the downlink control command increases the downlink transmission power, the downlink transmission power is reduced or, conversely, the downlink control command is transmitted. Even if it reduces transmission power,
The downlink transmission power may be increased. Downlink transmission power P
The change of the downlink transmission power by updating i (i = 1, 2) to r (Pi-C) + C is | (1-r)
(C-Pi) |, and its maximum value is | (1-r)
(C−Pmin) | or | (1-r) (C−Pmax) |. In this embodiment, the reference power C is defined as the central power (Pmax) between the maximum power Pmax and the minimum power Pmin of the downlink transmission power.
+ Pmin) / 2, the maximum value of the change can be reduced. Therefore, it is possible to reduce the influence of insufficient control of the downlink transmission power due to the control at each time Tint, thereby deteriorating the reception quality and increasing the downlink interference power due to the excessive downlink transmission power.

Next, another embodiment of the present invention will be described.

The transmission power control method for the cellular system according to the third embodiment is similar to the transmission power control method according to the third embodiment except that the reference power C is determined.
This is the same as the second embodiment described above. In the third embodiment, the reference power C is set to the maximum power Pmax of the downlink transmission power.

In this embodiment, similarly to the second embodiment, even if the reception of the downlink control command fails, the information on the downlink transmission power is not exchanged between the base stations and the downlink is transmitted. Can be adjusted to a value substantially equal to each other between the base stations. In this embodiment, for each time Tint, the downlink transmission power Pi (i = 1,
By updating 2) to r (Pi-C) + C, the downlink transmission power is increased by (1-r) (Pmax-Pi). Therefore, according to this method, the reception quality does not deteriorate due to insufficient downlink transmission power.

The transmission power control method for the cellular system according to the fourth embodiment is similar to the transmission power control method according to the fourth embodiment except that the reference power C is determined.
This is the same as the second embodiment described above. In the third embodiment, the reference power C is set to the minimum power Pmin of the downlink transmission power.

In this embodiment, similarly to the second embodiment, even if reception of a downlink control command fails, information on downlink transmission power is not exchanged between base stations. Can be adjusted to a value substantially equal to each other between the base stations. In this embodiment, for each time Tint, the downlink transmission power Pi (i = 1,
By updating 2) to r (Pi-C) + C, the downlink transmission power is reduced by (1-r) (Pi-Pmin). Therefore, in this method, the downlink transmission power does not become excessive and the interference wave power of the downlink is not increased.

Next, still another embodiment according to the present invention will be described.

The transmission power control method for the cellular system according to the fifth embodiment is the same as that of the second embodiment except for the method of determining the reference power C.

In the fifth embodiment, the main base station 21A for the mobile station 61A executing the soft handover
And the auxiliary base station 22A simultaneously calculate the median value of the transmission power for the mobile station 61A at the same time period, and use the median value as a statistical value of the transmission power as the control station 71A
Notify. The control station 71A communicates with each base station 21
A, the reference power C based on the statistical value notified from 22A
Are determined, and the respective base stations 21A, 22
Notify A. And each base station 21
At A and 22A, when updating the transmission power to the mobile station 61A, the reference power C represented by the notified reference value is used.

According to this method, similarly to the second embodiment, even if the reception of the downlink control command fails, the downlink transmission power Pi can be adjusted to be substantially equal between the base stations. it can. Further, by setting the reference power C, which is a value in the range where the downlink transmission power fluctuates in the implementation, for each mobile station, the difference between the implementation transmission power and the reference power C becomes smaller, so that the time Tint The variation of the downlink transmission power due to the update of the downlink transmission power every time becomes smaller, and the influence of the shortage or excess of the downlink transmission power can be reduced. Furthermore, in the control station 71A, the control value (statistical value) notified from the main base station 21A is used as a reference value. However, since the main base station 21A has the smallest average propagation loss to the mobile station 61A, the control value The highest reliability. Therefore, the fluctuation of the downlink transmission power due to the update of the downlink transmission power every time Tint can be further reduced.

The base station 21A, 22A and the control station 71A exchange a statistical value of downlink transmission power and a reference value representing the reference power C. These exchanges are performed in comparison with the control cycle of the transmission power control. Therefore, the transmission amount of control information between the base stations 21A and 22A and the control station 71A does not matter much. Also, even if a delay time occurs, if the delay time is the same between the base stations 21A and 22A, the downlink transmission power can be made equal between the base stations 231A and 22A without any problem. Therefore, the transmission amount of the control signal between the base stations 21A and 22A and the control station 71A is not increased so much, and the downlink transmission power is largely fluctuated, so that the downlink transmission power becomes insufficient or excessive. While suppressing the influence, the downlink transmission power
A and 22A can be made equal to each other.

The transmission power control method of the cellular system according to the sixth embodiment is the same as that of the fifth embodiment except that the control station 71A determines the reference power C.

In the sixth embodiment, the control station 71A determines the maximum statistical value among the statistical values of the downlink transmission power notified from the base stations 21A and 22A as the reference value representing the reference power C. Then, it notifies each of the base stations 21A and 22A.

In this embodiment, there is a difference in the downlink transmission power between the base stations 21A and 22A due to the reception error of the downlink control signal, and the downlink transmission power notified to the control station 71A from the respective base stations 21A and 22A. Are different from each other, the reference value representing the reference power C is determined using the statistic of the base station having the increased downlink transmission power. The value is not determined to be smaller than the value in the range where the power actually fluctuates. Therefore, it is possible to reduce the possibility that the downlink transmission power becomes insufficient at the time of updating the downlink transmission power for each time Tint, and reduce the probability of deterioration of the reception quality.

The transmission power control method for a cellular system according to the seventh embodiment is different from the fifth embodiment in that the base station uses a constant coefficient r instead of using a constant coefficient r, and the mobile station individually sets the coefficient. Same as the form.

In the seventh embodiment, there are a first coefficient r1 and a second coefficient r2 as candidates for the coefficient r. However, the first
Both the coefficient r1 and the second coefficient r2 are values greater than or equal to 0 and smaller than 1, but the second coefficient r2 is a value smaller than the first coefficient r1. The control station 71A communicates with each base station 21
When the difference between the maximum value and the minimum value of the statistical value of the downlink transmission power notified from A and 22A is smaller than a predetermined reference value, a first coefficient r1 is set as a coefficient r, and this is set to each base station. Notify the stations 21A and 22A. On the other hand, if the difference between the maximum value and the minimum value of the statistical value of the downlink transmission power notified from the respective base stations 21A and 22A is larger than a certain reference value, the second coefficient r2 is set as the coefficient r. This is notified to the respective base stations 21A and 22A. Then, each of the base stations 21A and 22A uses the notified coefficient r.

According to this method, the difference of the downlink transmission power becomes r times every time Tint, but the reception error probability of the downlink control command notified from the mobile station to the base station is high, and the downlink transmission power of the base station is high. When the difference between the powers is large, the coefficient r is set to a small value, so that the difference between the downlink transmission powers can be reduced in a short time. On the other hand, when the probability of the reception error of the downlink control command is low and the difference between the downlink transmission powers of the base stations is small, the coefficient r is set to a large value. Variations can be kept small, and the degree of downlink transmission power shortage or excess can be reduced.

The transmission power control method for a cellular system according to the eighth embodiment is different from the fifth embodiment in that the base station uses a fixed time Tint instead of using a fixed time Tint, and the mobile station individually sets the time Tint. This is the same as the embodiment.

In the eighth embodiment, a candidate for the time Tint has a first time Tint1 and a second time Tint2. Here, the second time Tint2 is set to a value smaller than the first time Tint1. The control station 71A communicates with each base station 21
When the difference between the maximum value and the minimum value of the statistical value of the downlink transmission power notified from A and 22A is smaller than a predetermined reference value, a first time Tint1 is set as the time Tint, and this is set to each base station. Notify the stations 21A and 22A. On the other hand, when the difference between the maximum value and the minimum value of the statistical value of the downlink transmission power notified from the respective base stations 21A and 22A is larger than a certain reference value, the control station 71A sets the time Tint as the second time.
Is set for each base station 21.
A, 22A is notified. And each base station 21
A and 22A use the notified time Tint.

According to this method, the difference in the downlink transmission power becomes r times every time Tint, but the reception error probability of the downlink control command notified from the mobile station to the base station is high, and the downlink transmission power of the base station is high. When the difference between the powers is large, the time Tint is set to a small value, so that the difference in the downlink transmission power can be reduced quickly. On the other hand, when the probability of the reception error of the downlink control command is low and the difference between the downlink transmission powers of the base stations is small, the time Tint is set to a large value. The frequency of the update is reduced, and the frequency with which the downlink transmission power becomes insufficient or excessive due to the fluctuation due to the update can be reduced.

The transmission power control method for a cellular system according to the ninth embodiment is implemented in a cellular system having the configuration shown in FIG. 7, as in the second embodiment. Procedure in which each of the mobile stations 61A and 62A measures the reception power of the first and second pilot signals 31 and 32, respectively, and establishes a line between the main base station and the auxiliary base station when performing communication. Is the same as in the second embodiment. Each time each of the base stations 21A and 22A receives the slot transmitted by the mobile station, the base station 21A, 22A measures its SIR,
Each time 1A, 62A receives a slot transmitted by the base station, the method of measuring its SIR is the same as in the second embodiment. Further, the first base station 2 which is the main base station of the first mobile station 61A executing the soft handover
1A and a second base station 22A, which is an auxiliary base station, provide the first mobile station 61A with the same information except for a downlink transmission power downlink control command.
a and the first auxiliary downlink signal 41b are transmitted in the same manner as in the second embodiment. First mobile station 6
1A combines and receives the downlink signals 41a and 41b, measures the downlink SIR, compares the measured downlink SIR value with the target downlink SIR value,
When the R value is smaller than the target downlink SIR value, the downlink control command is set to increase the power. When the measured downlink SIR value is larger than the target downlink SIR value, the downlink control command is set to decrease the power. A downlink control command is notified to the first and second base stations 21A and 22A, and the second mobile station 6
2A also notifies the first base station 21A of a downlink control command in the same manner as the second embodiment. Also, the method of uplink transmission power control is the same as in the second embodiment.

Note that the first mobile station 61A has a timer 610.
(FIG. 9), and the passage of time can be measured.

The following description will be made with reference to the flow chart. In the flow chart and the description thereof, power is treated as a decibel value.

FIG. 13 is a flow chart in which the mobile station 61A calculates the accumulated control value A and notifies the base station during the execution of the soft handover. When the soft handover is started, the mobile station 61A also initializes the accumulated control value A to 0 (step S301), and the measurement time Tm of the timer 610.
Is initialized to 0 (step S303). Then, every time a downlink control command is transmitted to the base station (Y in step S303)
ES), if the downlink control command indicates an increase in power (YES in step S304), the cumulative control value A
Is increased by a predetermined value ΔA (step S305), and when the downlink control command indicates a power phenomenon (NO in step S304), the cumulative control value A is reduced by a predetermined value ΔA (step S306). . Next, the timer 61
If the measured time Tm of 0 has passed the time Tint (YES in step S307), the cumulative control value A is notified to each base station (step S308), and step S30 is performed.
Repeat from 2.

FIG. 14 is a flow chart in which the base station receives the downlink control command from the mobile station and determines the downlink transmission power of the downlink during the execution of the soft handover. When the base station starts soft handover with the mobile station, if the base station is a main base station that has been transmitting to the mobile station for a long time (NO in step S401), the downlink transmission power P becomes If the base station is the auxiliary base station that has newly started transmission to the mobile station (step S401: YES), the downlink transmission power P is set to the initial value. It is set to P0 (step S402). As the initial value P0, any value within the control range of the downlink transmission power can be selected, but here, the maximum power Pmax of the downlink transmission power is set. Downlink control commands are sent from the mobile station at regular intervals. In step S403, when a newly notified downlink control command is present and the downlink control command indicates power increase (YES in step S404), the transmission power control unit 205 determines whether the downlink transmission power P Is increased by a predetermined value ΔP (step S405), and when the downlink control instruction indicates power reduction (NO in step S404), the transmission power control unit 2
05 decreases the transmission power P of the downlink by a predetermined value ΔP (step S406). Here, the predetermined value ΔP used in the base station is set equal to the predetermined value ΔA used in the mobile station.

Next, in step S407, when the cumulative control value A is received from the mobile station, the sum of the initial value P0 and the cumulative control value A is set as the reference power C (step S40).
8). Then, the transmission power control unit 205 determines that the value r (Pb−C) obtained by multiplying the difference (Pb−C) between the downlink transmission power Pb before the update and the reference power C by the coefficient r is the updated downlink transmission power Pa The downlink transmission power P is updated to r (Pb-C) + C so as to be equal to the difference (Pa-C) between the transmission power P and the reference power C (step S409). In this embodiment, the coefficient r is a predetermined constant value, and the coefficient r is a value of 0 or more and less than 1.

If the updated transmission power P is equal to the maximum power Pma
If it is larger than x (YE in step S410)
S), the downlink transmission power P is set to the maximum power Pmax (step S411). If the updated transmission power P is smaller than the minimum power Pmin (YES in step S412), the downlink transmission power P is set to the minimum power Pmin (step S412). Step S41
2). Then, the process is repeated from step S403 again.

According to this method, when soft handover is started, the difference | P1−P2 | between the downlink transmission power P1 of the main base station and the downlink transmission power P2 of the auxiliary base station is obtained.
However, if there is no reception error of the downlink control command, each time the cumulative control value A is notified, these downlink transmission powers P1 and P2
The difference | P1−P2 | is r times, so that the difference converges to zero. Therefore, the transmission powers of the base stations can be made equal to each other.

Further, in this method, the update for bringing the downlink transmission power P close to the reference power C is repeated. However, the reference power C calculated by the sum of the initial value P0 and the cumulative control value A is calculated in units of slots. P increases or decreases in the same manner, so that at the moment when the cumulative control value A is notified, the reference power C
And the downlink transmission power P substantially coincide with each other. Therefore,
In a line in which a reception error does not occur, the downlink transmission power P hardly changes due to the update of the downlink transmission power P, and the downlink transmission power P in which the reception error of the downlink control command has occurred is different from the reference power C. Only in this case, the downlink transmission power P can be brought close to the reference power C. Therefore, when the downlink transmission power of the auxiliary base station whose line quality is relatively poor has little effect on the transmission power control of the main base station whose line quality is relatively good, Therefore, only the downlink transmission power of the auxiliary base station is corrected. In this way, when making the downlink transmission powers equal among the base stations, the influence of the shortage or excess of the downlink transmission power is reduced.

The flow charts of FIGS. 13 and 14 are as follows.
The present invention can be implemented in exactly the same manner when the mobile station is setting up a line with only one base station while the soft handover is not being executed. When the mobile station performs the control of FIG. 13 even when the mobile station has set up a line with only one base station, when the soft handover is started or when a new auxiliary base station is added. Even if the control is continued in the same manner as in the flowchart of FIG. 13 without initializing the accumulated control value A, the control can be performed without any trouble.

The transmission power control method for a cellular system according to the tenth embodiment is implemented in a cellular system having the configuration shown in FIG. 7, as in the second embodiment. Procedure in which each of the mobile stations 61A and 62A measures the reception power of the first and second pilot signals 31 and 32, respectively, and establishes a line between the main base station and the auxiliary base station when performing communication. Is the same as in the second embodiment. Each time each of the base stations 21A and 22A receives the slot transmitted by the mobile station, the base station 21A, 22A measures its SIR,
Each time 1A, 62A receives a slot transmitted by the base station, the method of measuring its SIR is the same as in the second embodiment. Further, the first base station 2 which is the main base station of the first mobile station 61A executing the soft handover
1A and a second base station 22A, which is an auxiliary base station, provide the first mobile station 61A with the same information except for a downlink transmission power downlink control command.
a and the first auxiliary downlink signal 41b are transmitted in the same manner as in the second embodiment. First mobile station 6
1A combines and receives the downlink signals 41a and 41b, measures the downlink SIR, compares the measured downlink SIR value with the target downlink SIR value,
When the R value is smaller than the target downlink SIR value, the downlink control command is set to increase the power. When the measured downlink SIR value is larger than the target downlink SIR value, the downlink control command is set to decrease the power. A downlink control command is notified to the first and second base stations 21A and 22A, and the second mobile station 6
2A also notifies the first base station 21A of a downlink control command in the same manner as the second embodiment. Also, the method of uplink transmission power control is the same as in the second embodiment.

The following description will be made with reference to the flow chart. In the flow chart and the description thereof, power is treated as a decibel value.

FIG. 15 is a flow chart in which a base station receives a downlink control command from a mobile station and determines downlink transmission power during downlink during execution of soft handover. When the base station starts soft handover with the mobile station, if the base station is a main base station that has been transmitting to the mobile station for a long time (NO in step S501), the downlink transmission power P becomes If the transmission power for the mobile station is kept at the value immediately before, and the base station is an auxiliary base station that has newly started transmission to the mobile station (YES in step S501), the downlink transmission power P is set to the initial value. It is set to P0 (step S502). The initial value P0 is an arbitrary value within the control range of the downlink transmission power. Downlink control commands are included in slots transmitted by the mobile station to the base station. Upon receiving the slot from the mobile station, the base station (step S50)
3 (YES in step S504), if the downlink control command in the slot indicates an increase in power (YE in step S504).
S), the transmission power control unit 205 increases the downlink transmission power P by a predetermined value ΔP (step S505), and if the downlink control command indicates power reduction (NO in step S504), the transmission is performed. The power control unit 205 decreases the downlink transmission power P by a predetermined value ΔP (Step S
506).

Next, transmission power control section 205 calculates a value r (Pb-C) obtained by multiplying a difference (Pb-C) between downlink transmission power Pb before update and reference power C by coefficient r after update. The downlink transmission power P is updated to r (Pb-C) + C so as to be equal to the difference (Pa-C) between the downlink transmission power Pa and the reference power C (step S507). If the updated transmission power P is larger than the maximum power Pmax (step S508)
YES), the downlink transmission power P is set to the maximum power Pmax (step S509), and the updated transmission power P is set to the minimum power Pmi.
If it is smaller than n (YE in step S510)
S), the downlink transmission power P is set to the minimum power Pmin (step S511). And it repeats from step S503 again.

In this embodiment, the reference power C is the maximum power Pmax of the downlink transmission power. The coefficient r is a value of 0 or more and less than 1. However, in order to be able to increase or decrease the downlink transmission power P by a downlink control command from the mobile station, the increase amount of the downlink transmission power P in step S507 is used. Is set to be smaller than the increase / decrease ΔP of the transmission power in steps S505 and S506.
Therefore, {r (PC) + C} -P, which is the increment of the downlink transmission power P in step S507, that is, (1-
r) The value of the coefficient r is set so that (CP) becomes smaller than the increase / decrease ΔP of the downlink transmission power P in steps S505 and S506. Further, the setting range of the coefficient r is 1−ΔP / (C−P) <r <1. In this embodiment, since the reference power C is the maximum power Pmax of the downlink transmission power, the setting range of the coefficient r is 1−ΔP / (Pmax−P) <r
<1. Here, for example, the difference between Pmax and Pmin is 10
Assuming that dB and ΔP are 1 dB, 0.9 <r <1. However, if the coefficient r is set to a value very close to 1, the effect obtained in step S507 is reduced, and it is considered that the coefficient r should be set to about 0.95.

According to this method, as in the second embodiment, when the soft handover is started, the initial values of the downlink transmission powers of the main base station and the auxiliary base station are different.
There is a difference | P1−P2 | between the downlink transmission power P1 of the main base station and the downlink transmission power P2 of the auxiliary base station. If one or more base stations fail to receive the downlink control command, the difference | P1−P2 | between these downlink transmission powers P1 and P2 may increase. However, steps S504 to S50
In the control of the part 6, that is, in the part of increasing or decreasing the downlink transmission power by the downlink control command from the mobile station, each base station receives the same downlink control command notification, so that each base station If the reception of the downlink control command does not fail, the downlink transmission powers P1 and P2 are similarly increased or decreased, so that the difference | P1−P2 | between these downlink transmission powers P1 and P2 does not change.

On the other hand, in step S507, the main base station and the auxiliary base station update the downlink transmission powers P1 and P2 to r (P1-C) + C and r (P2-C) + C, respectively. Difference between downlink transmission power P1 and P2 | P1-P2 |
Becomes r | P1−P2 |. Thus, the difference | P1−P2 | of the downlink transmission power becomes r times every time a slot is received. Since the coefficient r is smaller than 1, unless the difference | P1−P2 | between the downlink transmission powers P1 and P2 increases due to a reception error of the new downlink control command, the difference between the control amounts decreases in a geometric series. To converge to 0. Also, even if a reception error of a new downlink control command occurs, the downlink transmission powers P1 and P2
Even if the difference | P1−P2 | of the difference increases, the difference | P1−P2 | can be reduced. Therefore, even if the reception of the downlink control command fails, the information on the downlink transmission power is not exchanged between the base stations, and the downlink transmission power P
1, P2 can be adjusted to be substantially equal between the base stations. In this way, the same effect as in the second embodiment can be obtained.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention. For example, in all the embodiments described above, instead of measuring the SIR at the base station, the desired wave power is measured and the uplink control of the uplink transmission power for the mobile station is performed for the uplink transmission power control. A method of determining the command such that the desired wave power is constant may be adopted.

A downlink control command for downlink transmission power control, which is notified from the mobile station to the base station, is information relating to a change in a relative value such as an increase in downlink transmission power or a decrease in downlink transmission power. Although an example in a certain case has been described, the downlink control command may be an absolute amount instead of a relative change amount of the control amount of the downlink transmission power.

In the above embodiment, an example of soft handover in which one mobile station sets up a line between two base stations has been described. However, in the case where soft handover is performed with three or more base stations, The present invention can be carried out in exactly the same manner.

Also, in the above embodiment, when the mobile station has set up a line with a plurality of base stations, all the base stations have their downlink transmission power reduced according to the downlink control command from the mobile station. Although controlled to be equal to each other, the value of the transmission power controlled to be equal to each other between the base stations as the internal transmission power value, the power actually transmitted in some base stations is: A method of temporarily increasing or decreasing the internal reference power value as a reference is also conceivable.

For example, during execution of soft handover,
When a plurality of base stations transmit to one mobile station, the base station having a relatively large propagation loss from the mobile station can perform downlink transmission even when transmitting simultaneously with the same transmission power as the other base stations. While the mobile station does not contribute much to the improvement of the reception quality, the effect of increasing the interference wave power on other mobile stations is the same as that of other base stations. Therefore, in order to suppress the interference wave power, the base station, whose propagation loss has temporarily increased from the mobile station, temporarily sets the transmission power to be smaller than the internal transmission power value, and the state disappears. In such a case, a method of returning the transmission power to be equal to the internal transmission power value can be considered.

As another example, in a system in which a base station transmits an uplink control command for increasing or decreasing the uplink transmission power of a mobile station to a mobile station, the base station performs uplink control for decreasing the uplink transmission power of the mobile station. When transmitting the command, if the reception quality of the signal from the mobile station in the base station is excessive, the downlink transmission power of the base station is temporarily set to be larger than the internal transmission power value. Then, in other states, a method of returning the downlink transmission power to be equal to the internal transmission power value may be considered.

In the case where the internal transmission power values that increase or decrease according to the downlink control command from the mobile station are made equal to each other between the base stations as in these methods, the present invention is implemented in exactly the same manner. be able to. Therefore, in the present invention, the transmission power control is not limited to the control of the power itself radiated from the antenna of the base station, but includes the control of the value of the transmission power handled internally by the base station.

In some systems, one slot transmitted by the base station includes a plurality of types of information such as a control command portion and a data portion, and the base station transmits at different powers depending on the type. It is also conceivable.
The present invention can be used for controlling the transmission power of a part of such a slot, or for controlling the transmission power when the same transmission power is set in the entire slot.

In the second to tenth embodiments described above, the case has been described where the maximum transmission power of the base station is equal to each other and, therefore, the sizes of all cells are equal to each other. The powers are different from each other, and even in the case where the cell size is different, the coefficient determined for each base station according to the maximum transmission power, the power transmitted from the antenna multiplied by the transmission power determined by the above embodiment, By doing so, the present invention can be implemented in exactly the same way. When the coefficients determined for each base station are different from each other, according to the present invention, the transmission powers before being multiplied by the coefficient become closer to each other, and the powers radiated from the antennas of the base station have different values. However, using the value multiplied by the coefficient determined by the base station as the transmission power is the same as when an amplifier or an attenuator is attached to the antenna or when the propagation loss fluctuates. Because of the variation, the diversity effect and the like of the present invention obtained at the cell boundary can be obtained in exactly the same manner.

[0138]

As described in the above embodiment, according to the present invention, the case where the propagation loss between the base station and the mobile station increases sharply, or the case where the base station transmits the downlink transmission power from the mobile station. Even when the error in the determination of the downlink control command is continuous, the communication between the base station and the mobile station can be continued without interrupting.

According to the present invention as described in the above embodiment, during execution of soft handover,
Even if the base station cannot correctly receive all downlink control commands for transmission power control transmitted from the mobile station,
The transmission power of a plurality of base stations transmitting to one mobile station can be made equal to each other.

Therefore, there is a high probability that the mobile station can correctly receive the uplink control command for uplink transmission power control from all the base stations that can minimize the propagation loss to the mobile station. Therefore, uplink transmission power control can be performed to increase the uplink channel capacity. In addition, even if the base station with the minimum propagation loss is replaced at a high speed, the multiple base stations transmit at the same downlink transmission power, so that the downlink diversity effect that the reception quality of the downlink is hardly degraded. Can be obtained.
Further, by preventing the transmission power of the downlink from becoming excessive, the increase of the interference wave can be suppressed, so that the channel capacity of the downlink can be increased. Also, in this control, the transmission amount with the control station does not become very large, and there is not much problem even if there is a delay time in the exchange of the control signal with the control station. There is no need for a high-speed line between them.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a cellular system to which a transmission power control method according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a frame configuration.

FIG. 3 is a diagram illustrating a change in received power due to fading.

FIG. 4 is a block diagram showing a configuration of a base station used in the cellular system shown in FIG.

FIG. 5 is a block diagram showing a configuration of a mobile station used in the cellular system shown in FIG.

FIG. 6 is a flowchart illustrating transmission power control according to the first embodiment.

FIG. 7 is a block diagram illustrating a cellular system to which a transmission power control method according to another embodiment of the present invention is applied.

FIG. 8 is a block diagram showing a configuration of a base station used in the cellular system shown in FIG.

FIG. 9 is a block diagram showing a configuration of a mobile station used in the cellular system shown in FIG.

FIG. 10 is a block diagram showing a configuration of a receiving circuit used in the mobile station device shown in FIG.

FIG. 11 is a block diagram showing a configuration of a control station used in the cellular system shown in FIG.

FIG. 12 is a flowchart of a base station in the second to eighth embodiments.

FIG. 13 is a flowchart of a mobile station according to the ninth embodiment.

FIG. 14 is a flowchart of a base station in the ninth embodiment.

FIG. 15 is a flowchart of a base station according to the tenth embodiment.

[Explanation of symbols]

 11, 12 cell 21, 22, 21A, 22A Base station 31, 32 Pilot signal 41, 41a, 41b, 42 Downlink signal 51, 52 Uplink signal 61, 62, 61A, 62A Mobile station 71, 71A Control station 201 antenna 202 transmission / reception duplexer 203 reception circuit 204 SIR measurement unit 205 transmission power control unit 206 transmission circuit 207 reception circuit output terminal 208 transmission circuit input terminal 210 timer 211 timer terminal 601 antenna 602 transmission / reception duplexer 603 reception circuit 604 SIR measurement unit 605 Transmission power control unit 606 Transmission circuit 607 Receiving circuit output terminal 608 Transmission circuit input terminal 610 Timer 611 Timer terminal 612 Pilot signal power measuring device 613 Pilot signal terminal 614 Cumulative control value updating unit 705 Notification receiving unit 06 reference value calculating section 707 notifies the transmission unit

Claims (41)

[Claims] An apparatus comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method for a cellular system that performs communication by setting a line between the plurality of base stations, while the mobile station sets a line with one or more base stations, Increasing or decreasing transmission power according to the control command each time a control command is received from the mobile station; and performing the transmission so that the transmission power of the base station after the increase or decrease approaches a predetermined reference power. Updating the power. The transmission power control method for a cellular system, comprising: 2. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method for a cellular system that performs communication by setting a line between the plurality of base stations, while the mobile station sets a line with one or more base stations, Increasing or decreasing the transmission power P according to the control command each time a control command is received from the mobile station; and calculating the difference between the increased or decreased transmission power Pa of the base station and a predetermined reference power C. (Pa−C) is the transmission power Pb before the update
R times the difference (Pb-C) between the reference power C and the predetermined reference power C (0
{Pa = r (Pb−C) + C} such that ≦ r <1),
Updating the transmission power P. A transmission power control method for a cellular system, comprising: 3. The product of the difference between the maximum value and the minimum value of the control range of the transmission power P and (1-r) is a change in the transmission power when the transmission power is increased or decreased according to the control command. 3. The transmission power control method for a cellular system according to claim 2, wherein said r is set to be smaller than. 4. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method of a cellular system for performing communication by setting a line between the mobile stations, while the mobile station sets a line with one or more base stations, the mobile station is connected to the base station. Transmitting a control command for the transmission power of the base station, and repeating the first transmission power control operation of changing the transmission power according to the control command received by the base station upon receiving the control command; A transmission power control method for a cellular system, comprising repeating a second transmission power control operation of updating the transmission power so that the transmission power of the station approaches a predetermined reference power. 5. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method of a cellular system for performing communication by setting a line between the mobile stations, while the mobile station sets a line with one or more base stations, the mobile station is connected to the base station. A first transmission power control operation of transmitting the control command of the transmission power of the base station and changing the transmission power according to the control command received by the base station upon receiving the control command is repeated, The base station repeats the second transmission power control operation of updating the transmission power so that the absolute value of the difference between the decibel value of the reference power and the decibel value of the transmission power decreases at a predetermined rate. Cellular system Transmission power control method. 6. The transmission power control method for a cellular system according to claim 1, wherein the reference power is a maximum transmission power. 7. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In the transmission power control method of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station sets a line between the plurality of base stations, Increasing or decreasing the transmission power in accordance with the control command each time a control command is received from a station; reducing the difference in transmission power between the plurality of base stations after the increase or decrease, and reducing the transmission power Updating the transmission power so as to approach a reference power commonly defined among the base stations. 8. A system comprising: a plurality of cells; a plurality of base stations arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or a plurality of base stations. In the transmission power control method of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station sets a line between the plurality of base stations, Each time a control command is received from the station, the transmission power P
And a difference (Pa−−) between the transmission power Pa of the base station after the increase or decrease and a reference power C commonly defined among the plurality of base stations.
ΔPa = so that C) becomes r times (0 ≦ r <1) the difference (Pb−C) between the transmission power Pb before the update and the reference power C.
r (Pb−C) + C｝; and updating the transmission power P. A transmission power control method for a cellular system. 9. The product of the difference between the maximum value and the minimum value of the control range of the transmission power P and (1-r) is the variation of the transmission power when the transmission power is increased or decreased according to the control command. 9. The transmission power control method for a cellular system according to claim 8, wherein said r is set to be smaller than. 10. A system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station sets a line between the plurality of base stations, A first transmission power control for transmitting a control command of a transmission power of a base station to each of the plurality of base stations and changing the transmission power according to the control command received by each of the plurality of base stations; While repeating the operation, reducing the difference in transmission power between the plurality of base stations, and updating the transmission power so that the transmission power approaches a reference power commonly determined among a plurality of base stations. Repeat the transmission power control operation Transmission power control method of a cellular system characterized by and. 11. A system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a transmission power control method of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station sets a line between the plurality of base stations, A first transmission power control for transmitting a control command of a transmission power of a base station to each of the plurality of base stations and changing the transmission power according to the control command received by each of the plurality of base stations; While repeating the operation, the absolute value of the difference between the decibel value of the reference power and the decibel value of the transmission power determined in common among the plurality of base stations decreases at a common rate among the plurality of base stations. As described above, each of the plurality of base stations Transmission power control method of a cellular system characterized by repeating the second transmission power control operation for updating the serial transmission power. 12. The system according to claim 7, wherein the reference power is a maximum power of transmission power.
3. The transmission power control method for a cellular system according to item 1. 13. The cellular system according to claim 7, wherein the reference power is an intermediate power between the decibel value of the maximum power and the decibel value of the minimum power of the transmission power. Transmission power control method. 14. The system according to claim 7, wherein the reference power is a minimum power of transmission power.
3. The transmission power control method for a cellular system according to item 1. 15. Each of the plurality of base stations calculates a statistic value of transmission power and notifies a control station, and the control station uses the statistic value of the plurality of base stations to calculate the reference power. And calculating a reference value indicating the reference power and notifying the plurality of base stations, and the plurality of base stations use the reference power represented by the notified reference value. Or a transmission power control method for a cellular system according to item 10. 16. The transmission power control method for a cellular system according to claim 15, wherein the maximum statistic value among the statistic values is used as the reference value. 17. Each of the plurality of base stations calculates a statistic of transmission power and notifies the control station of the statistic, and the control station uses the statistic of the plurality of base stations to calculate the reference power. And calculating a reference value representing the reference power and notifying the plurality of base stations, and the plurality of base stations use the reference power represented by the notified reference value. Transmission power control method for cellular system. 18. The transmission power control method for a cellular system according to claim 17, wherein a maximum statistic value among the statistic values is used as the reference value. 19. The transmission power of a cellular system according to claim 17, wherein the control station determines the common ratio according to a difference between the statistical values of the plurality of base stations. Control method. 20. The control station according to claim 17, wherein the frequency of updating the transmission power with the common ratio is determined according to a difference between the statistical values of the plurality of base stations. 3. The transmission power control method for a cellular system according to item 1. 21. The mobile station has information on a cumulative control value of transmission power in a base station, and updates the cumulative control value each time a transmission power control command of the base station is transmitted. Transmitting to the plurality of base stations at a time interval longer than the repetition time interval of the update operation, the plurality of base stations determine and use the reference power using the received cumulative control value. The transmission power control method for a cellular system according to claim 7, 8, 10, or 11, wherein: 22. The transmission power control method for a cellular system according to claim 7, wherein the plurality of base stations update the transmission power at the same time. 23. A system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or a plurality of base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile stations, a control command from the mobile station is received while the mobile station sets a line with one or more base stations. Means for increasing or decreasing the transmission power according to the control command, and means for updating the transmission power so that the transmission power of the base station after the increase or decrease approaches a predetermined reference power. A base station device of a cellular system, which is characterized by: 24. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile stations, a control command from the mobile station is received while the mobile station sets a line with one or more base stations. Means for increasing or decreasing the transmission power P in accordance with the control command, and the difference (Pa−C) between the transmission power Pa of the base station after the increase or decrease and the predetermined reference power C is calculated before the update. Transmission power Pb
R times the difference (Pb-C) between the reference power C and the predetermined reference power C (0
{Pa = r (Pb−C) + C} such that ≦ r <1),
Means for updating the transmission power P. A base station apparatus for a cellular system, comprising: 25. A change in transmission power when the product of the difference between the maximum value and the minimum value of the control range of the transmission power P and (1-r) increases or decreases the transmission power according to the control command. 25. The base station apparatus of a cellular system according to claim 24, wherein said r is set to be smaller than a minute. 26. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile station and the mobile station, the mobile station sets a line with one or a plurality of base stations. Transmitting a control command of the transmission power of the base station, and repeating the first transmission power control operation in which the base station receives the control command and changes the transmission power according to the received control command. Control means for repeating a second transmission power control operation for updating the transmission power so that the transmission power of the base station approaches a predetermined reference power, a cellular apparatus comprising: Base station equipment of the system. 27. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile station and the mobile station, the mobile station sets a line with one or a plurality of base stations. Transmitting a control command of the transmission power of the base station, and repeating the first transmission power control operation in which the base station receives the control command and changes the transmission power according to the received control command. Control means, the second transmission power control in which the base station updates the transmission power so that the absolute value of the difference between the decibel value of the predetermined reference power and the decibel value of the transmission power decreases at a predetermined rate. The second transmission power control that repeats the operation The base station apparatus of a cellular system characterized by a means. 28. The base station apparatus of a cellular system according to claim 23, wherein the reference power is a maximum power of a transmission power. 29. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile stations, while the mobile station sets a line with a plurality of base stations, each time a control command is received from the mobile station, Means for increasing or decreasing the transmission power in accordance with the control instruction; and reducing the difference in transmission power between the plurality of base stations after the increase or decrease, and the transmission power is determined in common among the plurality of base stations. Means for updating the transmission power so as to approach a reference power, the base station apparatus for a cellular system. 30. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the mobile stations, while the mobile station sets a line with a plurality of base stations, each time a control command is received from the mobile station, Means for increasing or decreasing the transmission power P in accordance with the control instruction; and a difference (Pa−) between the transmission power Pa of the base station after the increase or decrease and the reference power C commonly defined among the plurality of base stations.
ΔPa = so that C) becomes r times (0 ≦ r <1) the difference (Pb−C) between the transmission power Pb before the update and the reference power C.
r (Pb−C) + C}, and a means for updating the transmission power P. A base station apparatus for a cellular system. 31. A product of a difference between a maximum value and a minimum value of the control range of the transmission power P and (1-r) is a variation of the transmission power when the transmission power is increased or decreased according to the control instruction. 31. The base station apparatus of a cellular system according to claim 30, wherein said r is set to be smaller than. 32. A system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or a plurality of base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station is setting a line between the plurality of base stations, A first transmission power control operation of transmitting a control command for transmission power of a base station to the plurality of base stations, and changing the transmission power according to the control command received by each of the plurality of base stations. A first transmission power control unit that repeats the above, while reducing the difference between the transmission power of the plurality of base stations, and the transmission power so that the transmission power approaches a reference power commonly defined among a plurality of base stations. Update the second transmission power control action The base station apparatus of a cellular system and having a second transmission power control means to repeat. 33. A mobile communication system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. In a base station apparatus of a cellular system for performing communication by setting a line between the plurality of base stations, while the mobile station is setting a line between the plurality of base stations, A first transmission power control operation of transmitting a control command for transmission power of a base station to the plurality of base stations, and changing the transmission power according to the control command received by each of the plurality of base stations. The first transmission power control means that repeats, the absolute value of the difference between the decibel value of the reference power and the decibel value of the transmission power determined in common among the plurality of base stations is between the plurality of base stations. The plurality of groups are so reduced as to have a common ratio. The base station apparatus of a cellular system in which each station is characterized by having a second transmission power control means for repeating the second transmission power control operation for updating the transmission power. 34. The base station apparatus of a cellular system according to claim 29, wherein the reference power is a maximum power of transmission power. 35. The reference power according to claim 29, 30, 32, or 33, wherein the reference power is an intermediate power between the maximum decibel value of the transmission power and the minimum decibel value of the transmission power.
3. The base station device of the cellular system according to 1. 36. The base station apparatus for a cellular system according to claim 29, wherein the reference power is a minimum power of transmission power. 37. A system comprising: a plurality of cells; a plurality of base stations respectively arranged in the plurality of cells; and a mobile station moving in each cell, wherein the mobile station is connected to one or more base stations. A control station used in a cellular system for performing communication by setting a line between the plurality of base stations, wherein the control station is connected to the plurality of base stations, and the control station transmits transmission power from the plurality of base stations. Receiving means for receiving the statistical value of, calculating means for calculating a reference value representing the reference power using the received statistical value, transmitting means for transmitting the calculated reference value to the plurality of base stations, A control station for a cellular system, comprising: 38. The control station of a cellular system according to claim 37, wherein a maximum statistic value of the statistic values is used as the reference value. 39. The method according to claim 37, wherein the calculating unit determines a common ratio used by the plurality of base stations according to a mutual difference between the statistical values of the plurality of base stations. A control station for a cellular system according to claim 1. 40. The calculation unit, according to a difference between the statistical values of the plurality of base stations, determines a frequency of updating the transmission power of the plurality of base stations by a common ratio. The control station of a cellular system according to claim 37. 41. A mobile station used in a cellular system comprising a plurality of cells and a plurality of base stations respectively arranged in the plurality of cells, wherein the mobile station moves within each cell. And perform communication by setting a line with one or a plurality of base stations, wherein the mobile station has information on a cumulative control value of transmission power in the base station, and Means for updating the value each time a transmission command of the transmission power of the base station is transmitted, and updating the updated cumulative control value to the plurality of base stations at a time interval longer than a repetition time interval of the transmission power update operation. A mobile station in a cellular system, comprising: means for transmitting.