JP3323424B2 - Downlink transmission power control method in mobile communication system and mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system for performing site diversity, and more particularly to a mobile communication system for efficiently controlling the transmission power of a downlink radio signal transmitted from a base station to a mobile station via a radio channel. The present invention relates to a transmission power control method and a mobile communication system.

[0002]

2. Description of the Related Art In a wireless communication system, there is a transmission power control technique for minimizing transmission power. By performing transmission power control, effects such as saving power consumption and reducing interference with other wireless channels can be obtained. Particularly, in the CDMA system, since suppressing the amount of interference as low as possible directly leads to an increase in subscriber capacity, transmission power control is an essential technology.

There is site diversity as an interference reduction technique in the CDMA system. Site diversity is a technology that connects a mobile station and multiple base stations simultaneously and performs diversity combining between multiple base stations.Because it is possible to satisfy communication quality of a certain level or more with less transmission power,
Interference can be reduced and subscriber capacity can be increased.

In wireless communication, propagation loss generally does not match between an uplink from a mobile station to a base station and a downlink from a base station to a mobile station. Therefore, in order to improve the accuracy of the transmission power control, it is desirable to perform closed-loop transmission power control.

[0005] In this closed loop transmission power control,
As shown in FIG. 1, the base station transmission power is controlled based on the reception quality measured by the mobile station (see FIG. 1B), and the mobile station transmission power is controlled based on the reception quality measured by the base station. (See FIG. 1A). For example, when 1-bit information is used as the transmission power control command, the reception side measures the reception quality.
Is transmitted to the transmitting side as a transmission power control command when the predetermined quality is satisfied. On the transmitting side, if the transmission power control command is "0", the transmission power is increased by one step, and if it is "1", the transmission power is decreased by one step.
By performing this control continuously, the reception quality can be kept almost at the required quality.

[0006] As a method of closed loop transmission power control, there are a method using a control signal terminated between a mobile station and a base station, and a method using a control signal terminated between a mobile station and a base station control station. In the latter case, the control signal transmitted by the mobile station is received by a plurality of base stations during site diversity, combined, and then transmitted to the base station control station. Here, it is assumed that the control signal terminated between the mobile station and the base station is transmitted in layer 1, and is called a layer 1 control signal. Also, a control signal terminated between a mobile station and a base station control station is assumed to be transmitted in layer 3, and is called a layer 3 control signal.

[0007] The shorter the cycle of the closed loop transmission power control, the higher the accuracy of the transmission power control. Therefore, in the method of transmitting the transmission power control command as the layer 1 control signal, the layer 1 control signal does not perform the encoding process or the retransmission process, so that very high-speed transmission power control can be realized.

FIG. 2 shows an example in which a layer 1 control signal is used for downlink transmission power control. In this case, since a loop is formed between the mobile station and the base station, high-speed transmission power control with a small control delay can be performed, and a transmission power control error can be reduced. However, since the base station receives the layer 1 control signal independently, there is a problem in the control during the site diversity. In other words, if control is performed to maintain the quality after site diversity combining in the uplink at or above a certain level, a certain base station among a plurality of base stations that are simultaneously connected cannot maintain sufficient uplink reception quality,
The error rate of the layer 1 control signal transmitted from the mobile station to the base station may increase. In this base station, the transmission power control error increases, so that the interference increases and the CDM
In the A mobile communication system, it causes capacity degradation.

FIG. 10 shows an example in which a layer 3 control signal is used for downlink transmission power control. During site diversity,
The layer 3 control signal is combined at the exchange and then transmitted to the base station controller. Therefore, the reliability of the layer 3 control signal is extremely high, and the transmission power of each base station is always controlled based on the same information. However, due to the transmission delay of the layer 3 control signal, high-speed transmission power control cannot be performed, and the transmission power control error increases and the capacity deteriorates.
Another problem is that the amount of control signal transmission between the base station and the base station control station increases.

[0010] Conventional closed loop transmission power control in the downlink includes a method of always controlling with a layer 3 control signal and a method of always controlling with a layer 1 control signal.

[0011]

However, in a mobile communication system that performs site diversity, when transmission power control is always performed using a layer 1 control signal, a problem of an increase in transmission power control error during site diversity occurs.
In addition, when transmission power control is always performed using a layer 3 control signal, there is a problem in that an increase in transmission power control error when site diversity is not performed and an increase in inter-station transmission amount. Since an increase in transmission power control error causes an increase in interference, it causes a capacity degradation in a CDMA mobile communication system.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to improve the accuracy of transmission power control and reduce interference, thereby increasing the capacity of a CDMA mobile communication system. It is an object of the present invention to provide a downlink transmission power control method and a mobile communication system.

It is another object of the present invention to provide a downlink transmission power control method and a mobile communication system in a mobile communication system capable of performing transmission power control with a small control error and a small inter-station transmission amount.

Also, the present invention provides a downlink transmission power control method in a mobile communication system for reducing transmission power control when performing site diversity in downlink transmission power control by a transmission power control command terminated between a mobile station and a base station. And a mobile communication system.

[0015]

In order to solve the above-mentioned problems, the present invention provides a plurality of base stations, a mobile station connected to the base stations via a radio line, and a base station for controlling the base stations. A downlink transmission power control method in a mobile communication system having a control station and performing site diversity for simultaneously combining the mobile station and a plurality of base stations and performing diversity combining between the plurality of base stations, Performing a first downlink transmission power control using a first control signal transmitted from the mobile station and terminated at each base station and not combined during site diversity;
A downlink transmission power control method in a mobile communication system, characterized by performing additional downlink transmission power control using an additional control signal transmitted from the base station control station to a base station.

Also, in the present invention, the first downlink transmission power control is performed in a shorter cycle than the additional downlink transmission power control.

In the present invention, the first control signal is a layer 1 control signal.

In the present invention, the additional downlink transmission power control may further use a second control signal transmitted from the mobile station, terminated at the base station control station, and combined during site diversity. Features.

In the present invention, the second control signal is a layer 3 control signal.

Further, in the present invention, the first downlink transmission power control is performed during non-site diversity, and the additional downlink transmission power control is performed during site diversity.

Further, in the present invention, the first downlink transmission power control is control based on a reception SIR of a communication channel in the mobile station, and the additional downlink transmission power control is a bit of a communication channel in the mobile station. The control is based on an error rate or a frame error rate.

Further, in the present invention, the first downlink transmission power control is control based on reception SIR of a communication channel in the mobile station, and the additional downlink transmission power control is reception of a perch channel in the mobile station. SIR
The control is based on

In the present invention, both the first downlink transmission power control and the additional downlink transmission control are controls based on a bit error rate or a frame error rate of a communication channel in the mobile station. And

Further, in the present invention, the mobile station comprises:
During the site diversity, transmission of the bit corresponding to the first control signal is stopped.

Further, in the present invention, the first downlink transmission power control and the additional downlink transmission power control are both performed during site diversity.

In the present invention, the first downlink transmission power control controls the transmission power of each base station, and the additional downlink transmission power control controls the mobile station of the perch channel transmitted from each base station. The upper limit and the lower limit of the transmission power are set for each base station based on the reception SIR in.

In the present invention, the upper limit and the lower limit of the transmission power of each of the base stations are defined as a perch channel reception SIR of the perch channel transmitted from each of the base stations at the mobile station and a perch of each of the base stations. It is determined from channel transmission power and a target reception SIR of a downlink communication channel in the mobile station.

In the present invention, the second control signal notifies the perch channel reception SIR from the mobile station to the base station control station.
The upper and lower limits of the transmission power of each base station are determined based on the control signal of the above, and the additional control signal sets the upper and lower limits of the transmission power of each base station from the base station control station to each of the base stations. It is characterized by notification.

Also, in the present invention, the second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the additional control signal transmits the perch channel reception SIR to the base station control station. The base station notifies each base station, and each base station determines an upper limit and a lower limit of the transmission power of each base station based on the additional control signal.

Further, in the present invention, the upper limit and the lower limit of the transmission power of each of the base stations are defined as the reception SIR at the mobile station of the perch channel transmitted from one base station having the smallest propagation loss to the mobile station. , The perch channel transmission power at the one base station and the target reception SIR of the downlink communication channel at the mobile station.

In the present invention, the first downlink transmission power control controls the transmission power of each base station, and the additional downlink transmission power control controls the perch channel and the communication channel transmitted from each base station. Received SI at the mobile station
The transmission power of at least one base station is instructed to be corrected based on R.

Also, in the present invention, the second control signal notifies the base station control station of the correction for the at least one base station from the mobile station, and the additional control signal includes the correction of the at least one base station. The base station control station notifies the at least one base station of a correction for a station.

Further, in the present invention, the correction is performed by correcting the transmission power of the at least one base station so that the transmission power of each base station is equal to each other.

[0034] In the present invention, the correction is preferably performed so that a desired transmission power ratio is obtained between base stations based on a ratio of a received SIR of the perch channel transmitted from the base station at the mobile station. The transmission power of one base station is corrected.

Also, in the present invention, the first downlink transmission power control independently controls transmission power of each base station, and the additional downlink transmission power control performs transmission of the plurality of base stations during site diversity. It is characterized in that the power is controlled to be the same.

Also, in the present invention, each base station periodically transmits the transmission power control amount and the reception reliability by the first transmission power control in each base station during a predetermined period to the base station control station. Reporting, the base station controller notifies another base station of one transmission power control amount reported from one base station having the highest reception reliability among the base stations, and each of the other base stations performs By controlling the transmission power in each of the other base stations using the one transmission power control amount notified from the base station control station, the transmission power of the plurality of base stations is periodically controlled so as to be the same. It is characterized by that.

Also, in the present invention, each base station periodically reports the transmission power value at each base station to the base station control station, and the base station control station reports the transmission power value from one base station. Notifying the other base stations of the transmission power value, each of the other base stations controlling the transmission power at each of the other base stations to the one transmission power value notified from the base station control station. Features.

Further, in the present invention, the one transmission power value is the largest one among the transmission power values reported from the base station.

Further, in the present invention, the one transmission power value is a minimum transmission power value among the transmission power values reported from the base station.

Further, the present invention provides a first base station based on a plurality of base stations and a first control signal which is connected to the base stations via a radio line, is terminated at each base station, and is not combined during site diversity. A mobile station that transmits the first control signal so that downlink transmission power control is performed at each base station; and a base station that controls the base station and performs additional downlink transmission power control based on the additional control signal. A base station control station for transmitting the additional control signal to the base station so that the mobile station and a plurality of base stations are connected simultaneously to perform diversity combining between the plurality of base stations. A mobile communication system characterized by being performed.

Also, in the present invention, the first downlink transmission power control is performed in a shorter cycle than the additional downlink transmission power control.

In the present invention, the first control signal is a layer 1 control signal.

In the present invention, the mobile station further transmits a second control signal that is terminated at the base station control station and combined during site diversity in order to perform the additional downlink transmission power control. It is characterized by doing.

In the present invention, the second control signal is a layer 3 control signal.

In the present invention, the first downlink transmission power control is performed during non-site diversity, and the additional downlink transmission power control is performed during site diversity.

Further, in the present invention, the mobile station comprises:
The mobile station transmits the first control signal based on a reception SIR of a communication channel in the mobile station and the second control signal based on a bit error rate or a frame error rate of the communication channel in the mobile station.

Further, in the present invention, the mobile station comprises:
The mobile station transmits the first control signal based on the reception SIR of the communication channel and the mobile station transmits the second control signal based on the reception SIR of the perch channel.

Further, in the present invention, the mobile station comprises:
The mobile station transmits the first control signal and the second control signal based on a bit error rate or a frame error rate of a communication channel.

Further, in the present invention, the mobile station comprises:
During the site diversity, transmission of the bit corresponding to the first control signal is stopped.

Also, in the present invention, the first downlink transmission power control and the additional downlink transmission power control are both performed during site diversity.

In the present invention, the first downlink transmission power control controls the transmission power of each base station, and the additional downlink transmission power control controls the mobile station of the perch channel transmitted from each base station. The upper limit and the lower limit of the transmission power of each base station are set based on the reception SIR in.

In the present invention, the upper limit and the lower limit of the transmission power of each of the base stations are a perch channel reception SIR of the perch channel transmitted from each of the base stations at the mobile station and a perch of each of the base stations. It is determined from channel transmission power and a target reception SIR of a downlink communication channel in the mobile station.

Further, in the present invention, the second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the base station control station transmits the SIR.
The upper and lower limits of the transmission power of each base station are determined based on the control signal of the above, and the additional control signal sets the upper and lower limits of the transmission power of each base station from the base station control station to each of the base stations. It is characterized by notification.

In the present invention, the second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the additional control signal transmits the perch channel reception SIR to the base station control station. The base station notifies each base station, and each base station determines an upper limit and a lower limit of the transmission power of each base station based on the additional control signal.

Further, in the present invention, the upper limit and the lower limit of the transmission power of each base station are determined by the reception SIR at the mobile station of the perch channel transmitted from one base station having the smallest propagation loss to the mobile station. , The perch channel transmission power at the one base station and the target reception SIR of the downlink communication channel at the mobile station.

In the present invention, the first downlink transmission power control controls the transmission power of each base station, and the additional downlink transmission power control controls the perch channel and the communication channel transmitted from each base station. The mobile station is instructed to correct the transmission power of at least one base station based on the reception SIR.

Further, in the present invention, the second control signal notifies the correction to the at least one base station from the mobile station to the base station control station, and the additional control signal includes the at least one base station. The base station control station notifies the at least one base station of a correction for a station.

Further, in the present invention, the correction is performed by correcting the transmission power of the at least one base station so that the transmission powers of the respective base stations are equal to each other.

Also, in the present invention, the correction is performed so that a desired transmission power ratio between the base stations becomes a desired transmission power ratio based on a ratio of reception SIRs of the perch channel transmitted from the base station at the mobile station. The transmission power of one base station is corrected.

Further, in the present invention, the first downlink transmission power control independently controls the transmission power of each base station, and the additional downlink transmission power control performs transmission of the plurality of base stations during site diversity. The power is controlled to be the same.

Further, in the present invention, each base station periodically transmits the transmission power control amount and the reception reliability by the first transmission power control in each base station during a certain period to the base station control station. Reporting, the base station controller notifies another base station of one transmission power control amount reported from one base station having the highest reception reliability among the base stations, and each of the other base stations performs By controlling the transmission power in each of the other base stations using the one transmission power control amount notified from the base station control station, the transmission power of the plurality of base stations is periodically controlled so as to be the same. It is characterized by that.

Further, in the present invention, each base station periodically reports the transmission power value at each base station to the base station control station, and the base station control station reports the transmission power value from one base station. Notifying the other base stations of the transmission power value, each of the other base stations controlling the transmission power at each of the other base stations to the one transmission power value notified from the base station control station. Features.

Further, in the present invention, the one transmission power value is the largest one among the transmission power values reported from the base station.

Further, in the present invention, the one transmission power value is the smallest one among the transmission power values reported from the base station.

[0065]

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

First, a basic embodiment of a downlink transmission power control method for a mobile communication system according to the present invention will be described with reference to FIGS.

In the following description, a control signal that is terminated between a mobile station and a base station and that is not combined at the exchange during site diversity is called a layer 1 control signal. However,
Such control signals are generally not limited to layer 1 control signals, and layer 1 control signals are not generally defined to have such features. This layer 1 control signal is also called a transmission power control command or a transmission power control bit in terms of implementation. Further, a control signal terminated between the mobile station and the base station control station and combined at the exchange during site diversity is called a layer 3 control signal. However, such control signals are generally not limited to layer 3 control signals, and layer 3 control signals are not generally defined to have such characteristics. Further, in the following description, the base station control station is assumed to be functionally separated and independent from the exchange, but depending on the actual system configuration, the base station control station may be provided without providing a physically separated base station control station. It is also possible to integrate the functions of the station into the switching station by functional integration.

FIG. 4 shows a schematic configuration of a mobile communication system for realizing the downlink transmission power control system of the present invention.

In FIG. 4, a mobile station 5 is connected to base stations 1 and 2 via a radio line.
Is connected to the communication network 9 and the base station control station 11 via the. Note that the mobile communication system has a site diversity function, and a mobile station 5 and a plurality of base stations 1 and 2 can simultaneously connect a wireless channel and perform diversity combining between the plurality of base stations 1 and 2. . The exchange 7 has base stations 1, 2,
It has a function of connecting a line from the communication network 9 to a line from the communication network 9. The exchange 7 has a function of synthesizing signals received by the plurality of base stations 1 and 2 and a function of distributing a signal from the communication network 9 to the plurality of base stations 1 and 2 during site diversity. The base station control station 11 has a function of controlling the base stations 1 and 2.

In this mobile communication system, the mobile station 5 performs control via a wireless channel between the mobile station 5 and the base stations 1 and 2 in order to maintain communication. Control signals are classified into layer 1 control signals and layer 3 control signals. The layer 1 control signal is transmitted in layer 1 between the mobile station 5 and the base stations 1 and 2, and the terminal positions are the mobile station and the base station. In order to perform high-speed control, the layer 1 control signals are not combined by the exchange even during site diversity, and each base station 1, 2
Receive independently. The layer 3 control signal is transmitted to the mobile station 5 and the base station control station 1 through the base stations 1 and 2 and the exchange 7.
It is transmitted in Layer 3 between the two. The terminal positions of the layer 3 control signal are the mobile station 5 and the base station control station 11.

As shown in FIGS. 5 and 6, in the most basic embodiment of the present invention, a layer 1 control signal not combined with the exchange 7 is transmitted from the mobile station 5 to the base stations 1 and 2 in a short cycle. Thus, high-speed transmission power control that follows a change in propagation loss is realized.

However, it is difficult to achieve accurate transmission power control for a plurality of base stations 1 and 2 during site diversity only by downlink transmission power control using this layer 1 control signal, and time elapses. Accordingly, the error in the transmission power of each base station increases.

Therefore, in the present embodiment, as shown in FIGS. 5 and 6, the base station control station 11
2 to perform additional downlink transmission power control using an additional control signal transmitted in a long cycle, to further control the transmission power of each base station.

The downlink transmission power control using the layer 1 control signal from the mobile station 5 and the additional control signal from the base station control station 11 in combination makes it possible to perform highly accurate transmission power control. Therefore, in the case of a CDMA mobile communication system, it is possible to increase the capacity by reducing the amount of interference.

As an example of the most basic embodiment,
In the first basic embodiment shown in FIG.
Are transmitted from the mobile station 5 to the exchange 7 via the base stations 1 and 2, and are synthesized by the exchange 7 to be transmitted from the mobile station 5 to the base station control station 11. Is generated in the base station control station 11 from the layer 3 control signal supplied to the base station.

As an example of the first basic embodiment, in the second basic embodiment shown in FIG. 8, short period downlink transmission power control using a layer 1 control signal from the mobile station 5 is performed during non-site diversity. And the layer 3 from the mobile station 5
The long-term downlink transmission power control using an additional control signal from the base station control station 11 based on the control signal is performed during site diversity.

Further, as another example of the first basic embodiment, in the third basic embodiment shown in FIG. 9, a short cycle downlink transmission power control using a layer 1 control signal from the mobile station 5 is performed. In addition, a long period downlink transmission power control using an additional control signal from the base station control station 11 based on a layer 3 control signal from the mobile station 5 is also performed during site diversity.

On the other hand, as another example of the most basic embodiment, in the fourth basic embodiment shown in FIG. 10, additional control signals transmitted from the base station control station 11 to the base stations 1 and 2 are: It is generated in the base station control station 11 based on the current transmission power control state of each base station based on a report from each base station, and implements centralized transmission power control for all base stations.

Next, a first specific embodiment, which is a more specific embodiment based on the first and second basic embodiments, will be described with reference to FIGS.

FIG. 11 is a configuration diagram of a mobile station in the system of FIG. 4 according to the present embodiment. The transmission / reception separating unit 15 is used to share the antenna 13 for transmission and reception.
The signal received by receiving radio section 17 is despread by despreading section 19 and sent to combining section 21. The combining unit 21 combines signals despread with a plurality of codes during site diversity, but when not performing site diversity, despreads only one of the despreading units and does not perform combining. The demodulation unit 23 generates a bit string. The signal separation unit 25 extracts the user data and the layer 3 control signal, and outputs the user data to the terminal unit 27.
Then, the layer 3 control signal is sent to the layer 3 control signal receiving section 29. In the control unit 31, the reception SIR detected by the SIR detection unit 33 and the BER (Bit Er
ror Rate: bit error rate), layer 3 control signal receiving section 2
9, a layer 1 control signal and a layer 3 control signal for transmission power control are generated based on the layer 3 control signal received. From these control signals and user data from the terminal unit 27, a transmission signal is generated in the signal generation unit 37, modulated by the modulation unit 39, spread by the spreading unit 41, and then transmitted and received by the transmission radio unit 43 to the transmission / reception separation unit 15, antenna 13 to the base stations 1 and 2.

FIG. 12 is a configuration diagram of each of the base stations 1 and 2 in the system of FIG. 4 according to the present embodiment. Transmission / reception separation unit 4
Reference numeral 7 is used to share the antenna 15 for transmission and reception. The base station in FIG. 12 has channels 1 to n in order to communicate with a plurality of mobile stations. The common transmission amplifier 49 and the common reception amplifier 51 are shared by a plurality of users and are connected to channel blocks 50-1 to 50-n corresponding to channels 1 to n. Here, since the channel blocks 50-1 to 50-n have the same internal structure, only the channel block 50-1 for channel 1 will be described.

The signal received by receiving radio section 53 is despread by despreading section 55 and demodulated by demodulation section 57 to generate a bit string. The signal separation unit 59 extracts the user data, the layer 1 control signal, and the layer 3 control signal, and sends the user data and the layer 3 control signal to the exchange 7 and the layer 1 control signal to the control unit 61. The control unit 61 determines transmission power based on the layer 1 control signal extracted from the signal separation unit 59 and the layer 3 control signal from the base station control station 11, and sends the determined transmission power to the transmission radio unit 71 via the transmission power control unit 63. specify. Further, the control section 61 relays the layer 3 control signal from the base station control station 11 via the layer 3 control signal receiving section 73 and sends it to the signal generating section 65. From the control signal and the user data from the switching center 7, a transmission signal is generated in the signal generation unit 65, modulated by the modulation unit 67, spread by the spreading unit 69, and then transmitted from the transmission radio unit 71 to the common transmission amplifier 49 by the transmission / reception separation. Part 4
7. Transmit to the mobile station via antenna 45.

FIG. 13 shows an example of transmission power control using a layer 1 control signal during non-site diversity. In FIG. 13, the layer 1 control signal is periodically arranged in the radio frame. The mobile station notifies the base station of the reception quality by the layer 1 control signal, and the transmission power of the base station is controlled.

FIGS. 14 and 15 show examples of transmission power control using a layer 3 control signal during site diversity. FIG. 14 shows that the mobile station 5 transmits the layer 3 control signal to the base station control station 1.
1 shows an example of transmission. After the same layer 3 control signal transmitted by the mobile station 5 is received by the base station 1 and the base station 2, each is transmitted to the exchange 7, and the exchange 7 selects and combines, that is, selects the higher quality one. It is sent to the base station control station 11. The mobile station 5 notifies the base station control station 11 of the reception quality using the layer 3 control signal. Base station control station 1
1 controls the transmission power of each of the base stations 1 and 2 based on the notified reception quality. FIG. 15 shows a procedure in which the base station control station 11 controls the transmission power of the base station 1.

In this embodiment, the transmission power control method is switched according to the site diversity state. FIG.
6 shows an example of the switching procedure. In (1) of FIG.
Are connected to the base station 1. Since it is not during site diversity, transmission power control using a layer 1 control signal is performed. In (2), the base station control station 11 determines the start of the site diversity, and notifies the mobile station 5 and the base stations 1 and 2 of that. Each station receiving this signal is a layer 1
Switching from transmission power control using a control signal to transmission power control using a layer 3 control signal. In (3), layer 3
The mobile station 5 performs transmission power control using a control signal.
Sends a layer 3 control signal to the base station controller 11. The base station control station 11 uses each of the base stations 1, 2 using the layer 3 control signal.
Is performed. In (4), the base station control station 11 determines the end of the site diversity, and notifies the mobile station 5 accordingly.
And the base stations 1 and 2. Each station receiving this signal switches from transmission power control using the layer 3 control signal to transmission power control using the layer 1 control signal. In addition,
In this example, the connection with the base station 1 is released, and the mobile station 5 is connected only with the base station 2. In (5), transmission power control using a layer 1 control signal is performed between the mobile station 5 and the base station 2.

As described above, when the site diversity is not being performed, by performing the downlink transmission power control using the layer 1 control signal, the control delay and the control error can be reduced, and the inter-station transmission amount of the control signal can be further reduced. Also, during site diversity, by performing downlink transmission power control using a layer 3 control signal, transmission power of all base stations can be controlled with high accuracy. Furthermore, by properly using the two types of transmission power control methods depending on whether or not site diversity is performed, transmission power control with a smaller error can be realized, and thus the downlink capacity can be increased.

Next, an example in which the transmission power control based on the layer 1 control signal is performed based on the reception SIR and the transmission power control based on the layer 3 control signal is performed based on the error rate will be described with reference to FIG. In the mobile station 5, the control unit 31 can recognize the site diversity state based on the layer 3 control signal received by the layer 3 control signal receiving unit 29. When the site diversity is not being performed, the control unit 31 determines the layer 1 control signal based on the reception SIR detected by the SIR detection unit 33. For example, comparing the received SIR with the reference SIR,
When the received SIR is smaller than the reference SIR, the value is set to “0”, and when the received SIR is larger than the reference SIR, the value is set to “1”. When the base station receives the signal, the transmission power is increased by one step when it is "0", and is attenuated by one step when it is "1".
By performing this control continuously, the reception quality at the mobile station can be kept almost constant.

On the other hand, during site diversity, the control unit 3
1 is a layer 3 based on the BER detected by the BER detection unit 35
The control signal is determined and sent to the signal generator 37. The BER detection unit 35 may be a FER (Frame Error Rate) detection unit, and FER may be used instead of BER. FIG. 17 shows an example of the layer 3 control signal. The base station control station 11 that has received the layer 3 control signal determines the control amount of the base station transmission power based on the notified BER or FER,
Each base station is notified by a layer 3 control signal. Each base station controls the transmission power according to the instruction of the base station control station 11.

According to this example, when the layer 1 control signal is used, the transmission power control based on the received SIR is performed to follow the instantaneous fluctuation, and when the layer 3 control signal is used, the influence of the delay time is reduced. Since the transmission power control based on the bit error rate or the frame error rate is performed to reduce the inter-station transmission amount of the control signal, the transmission power control error can be reduced and the downlink capacity can be increased.

Next, similarly to the above-described example, when the site diversity is not being performed, the transmission power control using the layer 1 control signal based on the reception SIR of the communication channel is performed, and during the site diversity, the error used in the above-described example is performed. Layer 3 based on perception channel SIR instead of rate
It is also possible to perform transmission power control using a control signal.

In this example, the transmission power control based on the reception SIR is performed even during the site diversity, so that the measurement of BER or FER at the mobile station is not required. Also,
It is possible to realize a somewhat high-speed transmission power control during site diversity while using the layer 3 control signal.

Next, an example of performing control based on a bit error rate or a frame error rate in both cases of transmission power control using a layer 1 control signal and a layer 3 control signal will be described with reference to FIG. explain. The control unit 31 can recognize the site diversity state based on the layer 3 control signal received by the layer 3 control signal receiving unit 29. When the site diversity is not being performed, the control unit 31 determines the layer 1 control signal based on the BER detected by the BER detection unit 35. The BER detection unit 35 may be an FER detection unit, and FER may be used instead of BER. For example, BER (FE
R) is compared with the reference BER (FER), and the BER (FE
When R) is smaller than the reference BER (FER), it is set to “0”, and when it is larger, it is set to “1” and sent to the signal generator 37. When the base station receives the signal, the transmission power is increased by one step when it is "0", and is attenuated by one step when it is "1". By performing this control continuously, the reception quality at the mobile station can be kept almost constant.

On the other hand, during site diversity, the control unit 3
1 is the BER (F) detected by the BER (FER) detection unit 35.
ER) to determine a layer 3 control signal, and
Send to An example of the layer 3 control signal is the same as that shown in FIG. The base station control station 11 that has received the layer 3 control signal determines the control amount of the base station transmission power based on the notified BER (FER), and performs layer 3 control for each base station.
Notify by control signal. Each base station is a base station control station 11
The transmission power is controlled according to the instruction.

According to this example, the transmission power control using either the layer 3 control signal or the layer 1 control signal is based on the bit error rate or the frame error rate. SIR measurement becomes unnecessary, and switching of the measurement procedure becomes unnecessary. Therefore,
Control at the mobile station is simplified.

Subsequently, during site diversity, layer 1
An example of stopping transmission of bits used for transmission power control by a control signal will be described with reference to FIG. According to the layer 3 control signal received by the layer 3 control signal receiving unit 29,
The control unit 31 can recognize the site diversity state. During site diversity, transmission power control using a layer 3 control signal is performed. At this time, the control unit 31 instructs the transmission radio unit 43 to stop transmission of bits corresponding to the layer 1 control signal. . In accordance with this instruction, the transmitting radio unit 43 stops transmitting only the layer 1 control signal.

According to this example, during site diversity, transmission of bits used for transmission power control by the layer 1 control signal is stopped, so that the amount of uplink interference can be reduced and the uplink capacity can be increased.

Next, a second specific embodiment, which is a more specific embodiment based on the first and third basic embodiments, will be described with reference to FIGS.

FIG. 18 is a configuration diagram of the mobile station 5 in the system of FIG. 4 according to the present embodiment. The transmission / reception separating unit 115 is used to share the antenna 113 for transmission and reception. The signal received by receiving radio section 117 is despread by a plurality of despreading sections 119a, 119b, and 119c for a predetermined code. During site diversity, the despreading unit 11
In 9a, the downlink communication channel from the base station 1 is despread, and in the despreading unit 119b, the downlink communication channel from the base station 2 is despread. The despread signals are combined in the demodulation section 121a to generate a bit string. The demodulation unit 121
a at the SIR detection unit 123a connected to the
R is detected, and a layer 1 control signal (transmission power control command) to be transmitted to the base station is determined based on the detection result.

After demodulation, layer 1 control signal separating section 125 separates the layer 1 control signal, and determines the transmission power in transmitting radio section 141 based on the layer 1 control signal. After separating the layer 3 control signal in the layer 3 control signal separating section 127, the user data is transmitted to the terminal section 131.
Send to The despreading unit 119c receives the perch channel when each base station transmits as a control channel for selecting a base station in the mobile station, and detects the received SIR in the SIR detection unit 123b via the demodulation unit 121b. By alternately receiving in time, the reception S of a plurality of perch channels
IR detection becomes possible.

The control unit 129 performs control with the base station control station 11 using the layer 3 control signal. Also, the reception SIR detection result of the perch channel is transmitted to the base station control station 11.
The control to report to is also performed. The layer 3 control signal is inserted into the user data from the terminal unit 131 by the layer 3 control signal insertion unit 133, and the layer 1 control signal is inserted by the layer 1 control signal insertion unit 135. The modulation unit 137 modulates the user data. After being spread at 139, the signal is transmitted from the transmission radio section 141 via the transmission / reception separation section 115 and the antenna 113.

FIG. 19 is a configuration diagram of each of the base stations 1 and 2 in the system of FIG. 4 according to the present embodiment. Transmission / reception separation unit 1
47 is used to share the antenna 145 for transmission and reception. The base station in FIG. 19 has channels 1 to n in order to communicate with a plurality of mobile stations. The common transmission amplifier 149 and the common reception amplifier 151 are shared by a plurality of users, and are connected to channel blocks 150-1 to 150-n corresponding to channels 1 to n. Here, since the channel blocks 150-1 to 150-n have the same internal configuration, only the channel block 150-1 for channel 1 will be described.

The signal received by receiving radio section 153 is despread by despreading section 155 and then demodulated by demodulating section 157 to generate a bit string. The SIR detection section 165 connected to the demodulation section 157 detects the received SIR, and determines a layer 1 control signal to be transmitted to the mobile station based on the detection result. After demodulation, the layer 1 control signal separating section 159 separates the layer 1 control signal, and determines the transmission power in the transmission radio section 175 based on the layer 1 control signal. After separating the layer 3 control signal in the layer 3 control signal separating section 161, the user data is sent to the exchange 7.
The control unit 163 performs control with the base station control station 11 using the layer 3 control signal. It also relays a layer 3 control signal transmitted between the mobile station 5 and the base station control station 11. A layer 3 control signal insertion unit 167 inserts a layer 3 control signal and a layer 1 control signal insertion unit 169 into the user data from the switching center 7, and a modulation unit 171 modulates and spreads the user data. After spreading with
The signal is transmitted from the transmission radio section 175 via the common transmission amplifier 149, the transmission / reception separation section 147, and the antenna 145.

FIG. 20 is a flowchart of downlink transmission power control in this embodiment. In (1) of FIG.
2 transmits perch channels 1 and 2. FIG.
In (2) of 0, the mobile station 5 measures the reception SIR of the perch channels 1 and 2 and reports it to the base station control station 11 by a layer 3 control signal. At this time, since the layer 3 control signal is combined by the switching center 7, the signal can be satisfactorily received even if the reception quality at one base station is poor. Further, the base station control station 11 always holds the perch channel transmission power in the base stations 1 and 2 and the target reception SIR of the downlink communication channel in the mobile station 5. In (3) of FIG. 20, the base station control station 11 determines the upper and lower limits of the transmission power of each base station. An example of the determination method is described below.

[0104]

## EQU1 ## UL1 (dBm) = TP1 (dBm) -PSI
R1 (dB) + MSIR (dB) + α (dB) DL1 (dBm) = TP1 (dBm) −PSIR1 (d
B) + MSIR (dB) -β (dB) UL2 (dBm) = TP2 (dBm) -PSIR2 (d
B) + MSIR (dB) + α (dB) DL2 (dBm) = TP2 (dBm) −PSIR2 (d
B) + MSIR (dB) -β (dB) Here, UL1: upper limit of transmission power of base station 1 UL2: upper limit of transmission power of base station 2 DL1: lower limit of transmission power of base station 1 DL2: lower limit of transmission power of base station 1 Lower limit of transmission power TP1: Transmission power of perch channel 1 TP2: Transmission power of perch channel 2 PSIR1: Reception SIR of perch channel 1 PSIR2: Reception SIR of perch channel 2 MSIR: Target reception SIR of downlink communication channel in mobile station α + β: Transmission Power Control Range According to this determination method, the reception SIR at the mobile station of the downlink communication channel transmitted by each base station is close to the target reception SIR.

The base station control station 11 indicates the upper and lower limits of the base station transmission power determined as described above to each of the base stations 1 and 2 by using a layer 3 control signal. In (4) of FIG. 20, the mobile station 5 measures the received SIR after combining the downlink communication channels from the base stations 1 and 2. (5) of FIG.
Then, a layer 1 control signal (transmission power control command) is determined based on the measurement result, and is transmitted to each of the base stations 1 and 2 as a layer 1 control signal. Each base station controls the transmission power according to the layer 1 control signal, but does not exceed the upper and lower limits of the transmission power determined as described above.

By such control, the transmission power of the base station is set to α + β according to the fluctuation of the propagation loss between the mobile station and the base station.
(DB), and even if there is an error in the layer 1 control signal (transmission power control command), the error is suppressed within a certain range.

Therefore, even when downlink transmission power control is performed by a layer 1 control signal transmitted between a mobile station and a base station during site diversity, propagation loss is caused by a high-quality layer 3 control signal received and combined at each base station. The upper limit and the lower limit of the transmission power of each base station are set according to the transmission power control error due to the transmission error of the layer 1 control signal, and the high-speed termination terminated between the mobile station and the base station. Transmission power control can be realized, and capacity can be increased in a CDMA mobile communication system.

Next, with reference to FIG.
A third specific embodiment which is another more specific embodiment based on the basic embodiment will be described.

In the second specific embodiment described above, the case where the base station control station 11 determines the upper limit and the lower limit of the transmission power of each of the base stations 1 and 2 has been described. This determines the upper and lower limits of the transmission power in each base station during site diversity. The configurations of the mobile station and the base station according to the present embodiment are shown in FIGS.
Is the same as that shown in FIG.

FIG. 21 is a flowchart of downlink transmission power control in this embodiment. In FIG. 21, processes (1) and (2) until the mobile station 5 reports the perch channel reception SIR to the base station controller 11 are the same as those in the second specific embodiment, and thereafter, FIG. In (3), the base station control station 1 that has received the reception SIRs of the perch channels 1 and 2
1 reports them to each of the base stations 1 and 2 by a layer 3 control signal. Each of the base stations 1 and 2 keeps the target reception SIR of the downlink communication channel in the mobile station 5 at all times, and determines the upper and lower limits of the transmission power of its own base station as in the second specific embodiment. . (4) after that,
(5) is the same as in the second specific embodiment.

According to the transmission power control procedure, the second
Similarly to the specific embodiment, even when site diversity is performed, high-speed and low-error downlink transmission power control can be performed by the layer 1 control signal terminated between the mobile station and the base station, and CDMA mobile communication can be performed. Capacity can be increased in the system. Further, the base station control station 11 does not need to manage the transmission power of each base station,
The downlink transmission power can be controlled independently for each base station, and there is an advantage that the control load is distributed. Particularly, in a system in which the transmission power of the perch channel is frequently changed, it is not necessary to notify the base station control station 11 every time the change is made, so that the control traffic is reduced.

In FIG. 21, the base station control station 11 receives the SI signals of the perch channels 1 and 2 received from the mobile station 5.
Although R is sent to both the base stations 1 and 2 as it is, the base station control station 11 sends only the reception SIR of the perch channel 1 to the base station 1 and sends only the reception SIR of the perch channel 2 to the base station 2. It may be.

Next, a fourth specific embodiment, which is another specific embodiment based on the first and third basic embodiments, will be described.

In the present embodiment, when determining the upper and lower limits of the transmission power of each base station during site diversity, simultaneous connection is performed using the perch channel reception SIR of the base station having the smallest propagation loss with the mobile station. The upper and lower limits of the transmission power of all the base stations are determined. The configurations of the mobile station and the base station according to the present embodiment are the same as those shown in FIGS.

In this embodiment, TP1 (dBm) -PS
IR1 (dB) and TP2 (dBm) -PSIR2 (d
By comparing B), it can be determined that the base station having the smaller value is the base station having the smallest propagation loss. The following are the base station 1 and the mobile station 5
Is a method for determining the upper and lower limits of the transmission power of each base station when the propagation loss between the base stations is minimum.

[0116]

## EQU2 ## UL1 (dBm) = TP1 (dBm) -PSI
R1 (dB) + MSIR (dB) + α (dB) DL1 (dBm) = TP1 (dBm) −PSIR1 (d
B) + MSIR (dB) -β (dB) UL2 (dBm) = TP1 (dBm) -PSIR1 (d
B) + MSIR (dB) + α (dB) DL2 (dBm) = TP1 (dBm) −PSIR1 (d
B) + MSIR (dB) -β (dB) Here, UL1: upper limit of transmission power of base station 1 UL2: upper limit of transmission power of base station 2 DL1: lower limit of transmission power of base station 1 DL2: lower limit of transmission power of base station 1 Lower limit of transmission power TP1: Transmission power of perch channel 1 PSIR1: Reception SIR of perch channel 1 MSIR: Target reception SIR of downlink communication channel in mobile station α + β: Control range of transmission power According to this determination method, base stations 1 and 2 The upper and lower limits of the transmission power are the same. As in the second and third embodiments, the transmission power of each base station is controlled. However, the transmission power of the base station 1 and the transmission power of the base station 2 fluctuate in the same range. The transmission power from the base station can be kept almost the same within a certain accuracy. At this time, the reception SIR of the downlink communication channel transmitted by the base station 1 at the mobile station is close to the target reception SIR. On the other hand, the reception S at the mobile station of the downlink communication channel transmitted by the base station 2
Although the IR is smaller than the target reception SIR, the SIR after combining the two communication channels in the mobile station can satisfy the target reception SIR. Here, the transmission power from the base station 2 having a large propagation loss to the mobile station does not become too large. Therefore, the amount of interference is small,
Capacity can be increased in a CDMA mobile communication system.

In the fourth specific embodiment, when the perch channel transmission power of each base station is not known to the mobile station, the transmission power of each base station is reduced as in the third specific embodiment. The upper and lower limits are determined by each base station, and when the perch channel transmission power of each base station is known to the mobile station, the upper and lower limits of the transmission power of each base station are set as in the second specific embodiment. The determination may be made by the base station control station.

Next, a fifth specific embodiment which is another more specific embodiment based on the first and third basic embodiments will be described with reference to FIGS.

In the present embodiment, the transmission power of each base station is corrected based on the comparison result between the perch channel reception SIR and the communication channel reception SIR measured by the mobile station during site diversity. The configurations of the mobile station and the base station according to the present embodiment are the same as those shown in FIGS. 18 and 19, but the base station control station 11 is functionally incorporated in the exchange 7 and has a base station control function. It is assumed that control with the exchange is realized as control with the exchange 7.

In this embodiment, when the measured results of the perch channel reception SIR and the communication channel reception SIR at the mobile station 5 are as shown in the table shown in FIG. 23, the communication channel transmission power of the base station 1 becomes the perch channel transmission power. It can be seen that the communication channel transmission power of the base station 2 is 13 dB lower than the perch channel transmission power. Here, assuming that the perch channel transmission powers are equal, it is understood that the communication channel transmission power of the base station 2 is higher than the communication channel transmission power of the base station 1 by 2 dB.

Here, in order to make the transmission power from each base station the same, as shown in FIG. 22, if the mobile station 5 instructs the transmission power of the base station 2 to decrease by 2 dB by using a layer 3 control signal. Good. Also, the reception S of the perch channel
Any transmission power ratio can be set according to the IR ratio. These instructions may be issued as needed, for example, when the control amount is a certain value or more.

Note that the layer 3 control signal from the mobile station to each base station is sent to the target base station after being combined at the exchange, so that the reliability of the layer 3 control signal can be kept high. With the above control, the transmission power error at the base station having a high error rate of the layer 1 control signal can be reduced, and the transmission power ratio of each base station can be arbitrarily controlled, so that the capacity of the CDMD mobile communication system can be increased. Can be.

Next, a sixth specific embodiment, which is a more specific embodiment based on the fourth basic embodiment, will be described with reference to FIGS.

Although the configurations of the mobile station and the base station of this embodiment are the same as those shown in FIGS. 18 and 19, the base station control station 11 is functionally incorporated in the exchange 7 and It is assumed that the control with the central office is realized as the control with the exchange 7.

In this embodiment, the transmission power of the base station is corrected based on the result of comparing the average reception SIRs of the base stations during the site diversity. As shown in FIG. , Layer 1 received during a certain period
The control signal (transmission power control command) and the average reception SIR are periodically reported to the exchange 7 through the control unit 63. FIG.
In the example of 4, the base station 1 reports −2Δ (dB) and the base station 2 reports + 2Δ (dB) as its own transmission power control amount. Here, the transmission power control amount indicates the amount by which the transmission power should be controlled as a relative amount to the initial power, and the initial power is updated periodically. And FIG.
As shown in (1), the exchange 7 compares the average reception SIRs reported from the base stations 1 and 2, and notifies the other base stations of the transmission power control amount of the base station having the maximum average reception SIR. I do. Each base station notified of the transmission power control amount corrects the transmission power based on the notified transmission power control amount. For example, in FIG. 24, when the average reception SIR of the base station 1 is larger, the transmission power control amount in the base station 1−
The base station 2 is notified of 2Δ (dB). In the base station 2, the transmission power control amount -2Δ (d
B), the transmission power is corrected by the base station 1,
2 is controlled periodically so that the transmission powers of the two are the same.

As described above, in the base station 2 having a low reception SIR (reception reliability) and a high error rate of the layer 1 control signal, the base station 1 having a high reception SIR (reception reliability) receives the layer 1 control signal. Since the transmission power control amount is corrected, the transmission power of all the base stations is periodically controlled so as to be the same, and is maintained at substantially the same level. Power control error can be minimized, and CDM
The capacity can be increased in the A mobile communication system.

Next, a seventh specific embodiment, which is a more specific embodiment based on the fourth basic embodiment, will be described with reference to FIG.

In the present embodiment, the base station transmission power is corrected based on the result of comparing the transmission power values of the respective base stations during site diversity. The configurations of the mobile station and the base station according to the present embodiment are the same as those shown in FIGS. 18 and 19, but the base station control station 11 is functionally
It is assumed that control with the base station control station is realized as control with the exchange station 7.

In this embodiment, as shown in FIG. 26, each of base stations 1 and 2 periodically reports the transmission power value of its own base station to switching center 7. The exchange 7 compares the reported transmission power values and notifies the other base stations of the transmission power value of the base station having the maximum transmission power. In FIG. 26,
Since the transmission power value reported from the base station 2 is larger than 30 dBm, this transmission power value is notified to the base station 1. In the base station 1, the transmission power is corrected to 30 dBm.

By the above control, it is possible to reduce the transmission power error in the base station having a high error rate of the layer 1 control signal,
Since the transmission power values of the respective base stations can be kept substantially equal, the capacity can be increased in the CDMA mobile communication system. In addition, since the transmission power is adjusted to the higher one, the quality does not deteriorate.

In this case, the control for adjusting to the higher transmission power value is performed, but the control for adjusting to the lower transmission power value may be considered. In this case, the quality may be degraded, but the transmission power can be minimized, so that the capacity increases.

In the fifth to seventh specific embodiments described above, the switching center 7 is provided with the function of the base station control station 11, but the switching center 7 and the base station control station 11 are independent of each other. You may let it.

[0133]

As described above, according to the present invention,
By performing downlink transmission power control using a combination of a layer 1 control signal from a mobile station and an additional control signal from a base station control station, it becomes possible to perform high-precision transmission power control, and to perform CDMA mobile communication. It is possible to increase the capacity by reducing the amount of interference in the system.

Further, according to the present invention, when site diversity is not being performed, control delay and control error can be reduced by performing downlink transmission power control using a layer 1 control signal, and furthermore, inter-station transmission of control signals. It is possible to reduce the amount, and to perform the downlink transmission power control using the layer 3 control signal during the site diversity to determine whether or not the site diversity is performed so that the transmission power of all the base stations can be controlled with high accuracy. By properly using the two types of transmission power control methods, transmission power control with a smaller error can be realized, and thus the downlink capacity can be increased.

According to the present invention, when a layer 1 control signal is used, the reception SIR
When the layer 3 control signal is used, the transmission power control based on the bit error rate or the frame error rate is performed in order to reduce the influence of the delay time and reduce the inter-station transmission amount of the control signal. The transmission power control error can be reduced, and the downlink capacity can be increased.

Further, according to the present invention, regardless of the transmission power control using either the layer 3 control signal or the layer 1 control signal, since the control is based on the bit error rate or the frame error rate, the mobile station , The measurement of the reception SIR is unnecessary, and the switching of the measurement procedure becomes unnecessary. Therefore, control in the mobile station is simplified.

Further, according to the present invention, transmission of bits used for transmission power control by the layer 1 control signal is stopped during site diversity, so that the amount of uplink interference can be reduced and the uplink capacity can be increased.

Also, according to the present invention, when downlink transmission power control is performed by a layer 1 control signal transmitted between a mobile station and a base station during site diversity, a high-quality layer received and combined by each base station. (3) Since the upper and lower limits of the transmission power of each base station according to the propagation loss are set by the three control signals, the transmission power control error due to the transmission error of the layer 1 control signal is kept within a certain value, High-speed transmission power control terminated between base stations can be realized, and CD
The capacity can be increased in the MA mobile communication system.

Further, according to the present invention, the measurement result of the reception SIR of the perch channel is notified to each base station through the base station control station during the site diversity, and the measurement result of the reception SIR of the perch channel is obtained at each base station. Since the upper limit and the lower limit of the downlink transmission power of the own base station are determined based on the transmission power of the perch channel and the target value of the reception SIR of the communication channel, the base station control station manages the transmission power of each base station. There is no necessity, so that the downlink transmission power can be controlled independently for each base station, and the control load can be distributed. In particular, in a system in which the transmission power of the perch channel is frequently changed, it is not necessary to notify the base station control station every time the change is made, so that control traffic is reduced.

Further, according to the present invention, the reception SIR of the perch channel of the base station having the minimum propagation loss with the mobile station during site diversity, the transmission power of the base station, and the communication channel of the mobile station. Since the upper limit value and the lower limit value of the downlink transmission power of the base station are determined based on the target value of the reception SIR, the transmission power from each base station can be kept substantially the same within a certain accuracy, and thus the propagation loss is reduced. Eliminates excessive power from large base stations, reduces interference,
Capacity can be increased in a CDMA mobile communication system.

Further, according to the present invention, during site diversity, the mobile station determines the correction amount of the transmission power based on the measurement result of the reception SIR of the perch channel and the communication channel of each base station, and determines the correction amount for each. Since the base station is instructed to correct the transmission power of the base station, the transmission power error in the base station having a high error rate of the layer 1 control signal can be kept small, and the ratio of the transmission power from each base station can be reduced Can be arbitrarily controlled, and thus the capacity can be increased in the CDMA mobile communication system.

Further, according to the present invention, during site diversity, the transmission power control amount of another base station having the lowest reception reliability is determined based on the transmission power control amount of the base station having the highest reception reliability of the layer 1 control signal. Is periodically corrected so as to be the same as the transmission power control amount of the base station having the highest reliability. Therefore, it is possible to reduce the transmission power error in the base station having low reception reliability of the layer 1 control signal. Therefore, high-speed transmission power control terminated between a mobile station and a base station can be realized with a small error, and the capacity can be increased in a CDMA mobile communication system.

Further, according to the present invention, during site diversity, the exchange determines the transmission power value based on the transmission power periodically reported from each base station, and corrects the transmission power value of each base station. Therefore, the transmission power error can be kept small in the base station having a high error rate of the layer 1 control signal, and the capacity can be increased in the CDMA mobile communication system.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a conventional example of closed-loop transmission power control.

FIG. 2 is a diagram for explaining a conventional example of downlink transmission power control using a layer 1 control signal.

FIG. 3 is a diagram for explaining a conventional example of downlink transmission power control using a layer 3 control signal.

FIG. 4 is a block diagram showing a schematic configuration of a mobile communication system that realizes the downlink transmission power control method of the present invention.

FIG. 5 is a block diagram showing the most basic embodiment of the downlink transmission power control method of the present invention.

FIG. 6 is a sequence diagram showing the most basic embodiment of the downlink transmission power control method of the present invention.

FIG. 7 is a block diagram showing a first basic embodiment of a downlink transmission power control method according to the present invention.

FIG. 8 is a sequence diagram showing a second basic embodiment of the downlink transmission power control method of the present invention.

FIG. 9 is a sequence diagram showing a third basic embodiment of the downlink transmission power control method of the present invention.

FIG. 10 is a block diagram showing a fourth basic embodiment of the downlink transmission power control method of the present invention.

FIG. 11 is a block diagram showing a configuration of a mobile station in the system of FIG. 4 according to the first specific embodiment of the downlink transmission power control method of the present invention.

FIG. 12 is a block diagram showing a configuration of a base station in the system of FIG. 4 according to the first specific embodiment of the downlink transmission power control method of the present invention.

FIG. 13: Layer 1 during non-site diversity in the first specific embodiment of the downlink transmission power control method of the present invention
The figure which shows the example of the transmission power control using a control signal.

FIG. 14 is a diagram showing a part of an example of transmission power control using a layer 3 control signal during site diversity in the first specific embodiment of the downlink transmission power control method of the present invention.

FIG. 15 is a diagram showing the rest of the example of the transmission power control using the layer 3 control signal during the site diversity in the first specific embodiment of the downlink transmission power control method according to the present invention.

FIG. 16 is a sequence diagram showing a transmission power control method switching procedure according to a site diversity state in the first specific embodiment of the downlink transmission power control method of the present invention.

FIG. 17 is a diagram showing an example of a layer 3 control signal used in the first specific embodiment of the downlink transmission power control method according to the present invention.

FIG. 18 is a block diagram showing a configuration of a mobile station in the system of FIG. 4 according to a second specific embodiment of the downlink transmission power control method of the present invention.

FIG. 19 is a block diagram showing a configuration of a base station in the system of FIG. 4 according to a second specific embodiment of the downlink transmission power control method of the present invention.

FIG. 20 is a sequence diagram showing a procedure of transmission power control in a second specific embodiment of the downlink transmission power control method of the present invention.

FIG. 21 is a sequence diagram showing a procedure of transmission power control in a third specific embodiment of the downlink transmission power control method of the present invention.

FIG. 22 is a diagram illustrating transmission power control in a fifth specific embodiment of the downlink transmission power control method according to the present invention.

FIG. 23 is a diagram showing an example of a reception SIR of a perch channel and a communication channel of each base station used in the fifth specific embodiment of the downlink transmission power control method of the present invention.

FIG. 24 is a diagram showing an example of a transmission power value of each base station used in the sixth specific embodiment of the downlink transmission power control method of the present invention.

FIG. 25 is a diagram showing transmission power control in a sixth specific embodiment of the downlink transmission power control method of the present invention.

FIG. 26 is a diagram showing transmission power control in a seventh specific embodiment of the downlink transmission power control method of the present invention.

[Explanation of symbols]

 1, 2 base station 5 mobile station 7 switching station 9 communication network 11 base station control station

──────────────────────────────────────────────────続 き Continuation of the front page (72) Takaaki Sato, inventor NTT Mobile Communication Network Co., Ltd. 2-1-1 Toranomon, Minato-ku, Tokyo (56) References JP-A-8-116306 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B ^7/ 24-7/26 102 H04Q ^7/ 00-7/38

Claims (50)

(57) [Claims] 1. A mobile station, comprising: a plurality of base stations; a mobile station connected to the base station via a radio line; and a base station control station for controlling the base station. A downlink transmission power control method in a mobile station communication system in which site diversity for simultaneously connecting the plurality of base stations and performing diversity combining between the plurality of base stations is performed. Using the first control signal that is not synthesized
A downlink transmission power control method in a mobile communication system, comprising: performing downlink transmission power control on the base station, and performing additional downlink transmission power control using an additional control signal transmitted from the base station control station to the base station. 2. The downlink transmission power control method in a mobile communication system according to claim 1, wherein the first downlink transmission power control is performed in a shorter cycle than the additional downlink transmission power control. 3. The downlink transmission power control method in a mobile communication system according to claim 1, wherein the first control signal is a layer 1 control signal. 4. The additional downlink transmission power control further using a second control signal transmitted from the mobile station and terminated at the base station control station and combined during site diversity. 2. A downlink transmission power control method in the mobile communication system according to 1. 5. The method according to claim 4, wherein the second control signal is a layer 3 control signal. 6. The mobile communication system according to claim 4, wherein the first downlink transmission power control is performed during non-site diversity, and the additional downlink transmission power control is performed during site diversity. Downlink transmission power control method. 7. The first downlink transmission power control is a control based on a reception SIR of a communication channel in the mobile station, and the additional downlink transmission power control is a bit error rate or a frame error of a communication channel in the mobile station. 7. The downlink transmission power control method in a mobile communication system according to claim 6, wherein the control is based on a rate. 8. The first downlink transmission power control is control based on reception SIR of a communication channel in the mobile station, and the additional downlink transmission power control is control based on reception SIR of a perch channel in the mobile station. The downlink transmission power control method in a mobile communication system according to claim 6, wherein: 9. The control method according to claim 1, wherein the first downlink transmission power control and the additional downlink transmission power control are both based on a bit error rate or a frame error rate of a communication channel in the mobile station. 7. The downlink transmission power control method in the mobile communication system according to 6. 10. The downlink transmission power control method in a mobile communication system according to claim 6, wherein said mobile station stops transmission of a bit corresponding to said first control signal during site diversity. 11. The downlink transmission power control method in a mobile communication system according to claim 4, wherein both the first downlink transmission power control and the additional downlink transmission power control are performed during site diversity. 12. The first downlink transmission power control controls transmission power of each base station, and the additional downlink transmission power control is based on a reception SIR at the mobile station of a perch channel transmitted from each base station. 12. The downlink transmission power control method in a mobile communication system according to claim 11, wherein an upper limit and a lower limit of the transmission power of each base station are set. 13. An upper limit and a lower limit of the transmission power of each base station are a perch channel reception SIR of the perch channel transmitted from each base station at the mobile station, a perch channel transmission power of each base station, 13. The downlink transmission power control method in a mobile communication system according to claim 12, wherein the downlink transmission power control method is determined from a target reception SIR of a downlink communication channel in the mobile station. 14. The second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the base station control station transmits the perch channel reception SIR to the base station control station based on the second control signal. The upper and lower limits of the transmission power of the base station are determined, and the additional control signal notifies the upper and lower limits of the transmission power of each base station from the base station control station to the respective base stations. A downlink transmission power control method in the mobile communication system according to the above. 15. The second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the additional control signal transmits the perch channel reception SIR from the base station control station to each of the base station control stations. The base station is notified, and each base station determines an upper limit and a lower limit of transmission power of each base station based on the additional control signal.
4. The downlink transmission power control method in the mobile communication system according to 3. 16. An upper limit and a lower limit of the transmission power of each base station are: a reception SIR of the perch channel transmitted from one base station having the smallest propagation loss to the mobile station at the mobile station; and the one base station. 13. The downlink transmission power control method in a mobile communication system according to claim 12, wherein the transmission power is determined from a perch channel transmission power and a target reception SIR of a downlink communication channel in the mobile station. 17. The first downlink transmission power control controls transmission power of each base station, and the additional downlink transmission power control controls reception of a perch channel and a communication channel transmitted from each base station at the mobile station. 12. The downlink transmission power control method in a mobile communication system according to claim 11, wherein an instruction to correct transmission power of at least one base station is issued based on the SIR. 18. The second control signal notifies a correction for the at least one base station from the mobile station to the base station control station, and the additional control signal includes a correction for the at least one base station. 2. The system according to claim 1, wherein the base station controller notifies the at least one base station.
8. The downlink transmission power control method in the mobile communication system according to 7. 19. The downlink transmission power in a mobile communication system according to claim 17, wherein the correction corrects the transmission power of the at least one base station so that the transmission power of each base station becomes equal to each other. Control method. 20. The transmission of at least one base station so as to obtain a desired transmission power ratio between base stations based on a ratio of received SIRs of the perch channel transmitted from the base station at the mobile station. 18. The downlink transmission power control method in a mobile communication system according to claim 17, wherein the power is corrected. 21. The first downlink transmission power control independently controls the transmission power of each base station, and the additional downlink transmission power control makes the transmission powers of the plurality of base stations the same during site diversity. 2. The downlink transmission power control method in a mobile communication system according to claim 1, wherein the control is performed as follows. 22. Each base station periodically reports a transmission power control amount and a reception reliability by the first transmission power control in each base station during a predetermined period to the base station control station, and The station control station notifies the other base station of one transmission power control amount reported from one base station having the highest reception reliability among the base stations, and each of the other base stations has a different one of the other base stations. The transmission power of each of the plurality of base stations is controlled periodically by controlling the transmission power in each of the plurality of base stations by using the one transmission power control amount notified from the base station control station. The downlink transmission power control method in the mobile communication system according to claim 21. 23. Each base station periodically reports a transmission power value of each base station to the base station control station, and the base station control station transmits one transmission power value reported from one base station to another base station. The base station, and each of the other base stations controls the transmission power in each of the other base stations to the one transmission power value notified from the base station control station. 22. The downlink transmission power control method in the mobile communication system according to item 21. 24. The downlink transmission power control method in a mobile communication system according to claim 23, wherein the one transmission power value is the largest one among transmission power values reported from a base station. 25. The downlink transmission power control method in a mobile communication system according to claim 23, wherein the one transmission power value is a minimum transmission power value reported from a base station. 26. A first downlink transmission power control based on a plurality of base stations and a first control signal connected to the base stations via a radio line, terminated at each base station, and not combined during site diversity. And a mobile station that transmits the first control signal so that each base station performs the first control signal, and controls the base station so that additional downlink transmission power control based on the additional control signal is performed at the base station. A base station control station for transmitting an additional control signal to the base station, wherein site diversity for simultaneously connecting the mobile station and a plurality of base stations and performing diversity combining between the plurality of base stations is performed. Characteristic mobile communication system. 27. The mobile communication system according to claim 26, wherein the first downlink transmission power control is performed in a shorter cycle than the additional downlink transmission power control. 28. The mobile communication system according to claim 26, wherein the first control signal is a layer 1 control signal. 29. The mobile station further transmits a second control signal terminated at the base station control station and combined during site diversity to perform the additional downlink transmission power control. The mobile communication system according to claim 26, wherein 30. The mobile communication system according to claim 29, wherein said second control signal is a layer 3 control signal. 31. The mobile communication system according to claim 29, wherein the first downlink transmission power control is performed during non-site diversity, and the additional downlink transmission power control is performed during site diversity. 32. The mobile station, comprising: the first control signal based on a reception SIR of a communication channel in the mobile station;
The mobile communication system according to claim 31, wherein the second control signal is transmitted based on a bit error rate or a frame error rate of a communication channel in the mobile station. 33. The mobile station, comprising: the first control signal based on a reception SIR of a communication channel in the mobile station;
The mobile communication system according to claim 31, wherein the second control signal is transmitted based on a reception SIR of a perch channel in the mobile station. 34. The mobile station transmits the first control signal and the second control signal based on a bit error rate or a frame error rate of a communication channel in the mobile station. A mobile communication system according to claim 1. 35. The mobile communication system according to claim 31, wherein the mobile station stops transmitting a bit corresponding to the first control signal during site diversity. 36. The mobile communication system according to claim 29, wherein both the first downlink transmission power control and the additional downlink transmission power control are performed during site diversity. 37. The first downlink transmission power control controls transmission power of each base station, and the additional downlink transmission power control is based on a reception SIR of the perch channel transmitted from each base station at the mobile station. 37. The mobile communication system according to claim 36, wherein an upper limit and a lower limit of the transmission power of each base station are set. 38. An upper limit and a lower limit of the transmission power of each base station, a perch channel reception SIR at the mobile station of a perch channel transmitted from each base station, a perch channel transmission power at each base station, The mobile communication system according to claim 37, wherein the mobile communication system is determined from a target reception SIR of a downlink communication channel in the mobile station. 39. The second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the base station control station transmits the perch channel reception SIR based on the second control signal. 39. An upper and lower limit of transmission power of the base station is determined, and the additional control signal notifies the upper and lower limits of transmission power of each base station from the base station control station to each of the base stations. A mobile communication system according to claim 1. 40. The second control signal notifies the perch channel reception SIR from the mobile station to the base station control station, and the additional control signal transmits the perch channel reception SIR from the base station control station to each of the base station control stations. 39. The base station, wherein each base station determines upper and lower limits of transmission power of the base station based on the additional control signal.
A mobile communication system according to claim 1. 41. An upper limit and a lower limit of the transmission power of each base station, the reception SIR of the perch channel transmitted from one base station having the smallest propagation loss to the mobile station at the mobile station, and the one base station 38. The mobile communication system according to claim 37, wherein the mobile communication system is determined from a perch channel transmission power of the mobile station and a target reception SIR of a downlink communication channel in the mobile station. 42. The first downlink transmission power control controls a transmission power of each base station, and the additional downlink transmission power control controls reception SIR at a mobile station of a perch channel and a communication channel transmitted from each base station. 37. The mobile communication system according to claim 36, wherein the mobile communication system instructs correction of transmission power of at least one base station on the basis of: 43. The second control signal notifies a correction for the at least one base station from the mobile station to the base station control station, and the additional control signal includes a correction for the at least one base station. 5. The base station control station notifies the at least one base station.
3. The mobile communication system according to 2. 44. The mobile communication system according to claim 42, wherein said correction corrects transmission power of said at least one base station so that transmission power of each base station becomes equal to each other. 45. The transmission of the at least one base station such that a desired transmission power ratio is obtained between base stations based on a ratio of reception SIRs of the perch channel transmitted from the base station at the mobile station. The mobile communication system according to claim 42, wherein the power is corrected. 46. The first downlink transmission power control independently controls the transmission power of each base station, and the additional downlink transmission power control makes the transmission powers of the plurality of base stations the same during site diversity. 27. The mobile communication system according to claim 26, wherein the control is performed as follows. 47. Each base station periodically reports, to the base station control station, a transmission power control amount and a reception reliability by the first transmission power control during a fixed period in each base station, The station control station notifies the other base station of one transmission power control amount reported from one base station having the highest reception reliability among the base stations, and each of the other base stations has a different one of the other base stations. The transmission power of each of the plurality of base stations is controlled periodically by controlling the transmission power in each of the plurality of base stations by using the one transmission power control amount notified from the base station control station. 47. The mobile communication system according to claim 46. 48. Each base station periodically reports a transmission power value at each base station to the base station control station, and the base station control station transmits one transmission power value reported from one base station to another base station. The base station, and each of the other base stations controls the transmission power in each of the other base stations to the one transmission power value notified from the base station control station. 46. The mobile communication system according to 46. 49. The mobile communication system according to claim 48, wherein said one transmission power value is a maximum transmission power value among transmission power values reported from a base station. 50. The mobile communication system according to claim 48, wherein said one transmission power value is the smallest among transmission power values reported from a base station.