JPH11308655A - Transmission power control method at execution of soft hand-over and execution device therefor - Google Patents

Transmission power control method at execution of soft hand-over and execution device therefor

Info

Publication number
JPH11308655A
JPH11308655A JP10683698A JP10683698A JPH11308655A JP H11308655 A JPH11308655 A JP H11308655A JP 10683698 A JP10683698 A JP 10683698A JP 10683698 A JP10683698 A JP 10683698A JP H11308655 A JPH11308655 A JP H11308655A
Authority
JP
Japan
Prior art keywords
transmission power
power control
control information
base station
open
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP10683698A
Other languages
Japanese (ja)
Other versions
JP3343214B2 (en
Inventor
Nobukazu Doi
Takashi Hasegawa
Takashi Yano
信数 土居
隆 矢野
敬司 長谷川
Original Assignee
Hitachi Ltd
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd, 株式会社日立製作所 filed Critical Hitachi Ltd
Priority to JP10683698A priority Critical patent/JP3343214B2/en
Publication of JPH11308655A publication Critical patent/JPH11308655A/en
Application granted granted Critical
Publication of JP3343214B2 publication Critical patent/JP3343214B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To increase a system capacity by controlling the transmission power of a traffic channel from each base station in response to a level of each reference signal reception SIR measured by a mobile station for reducing interference with an adjacent cell, while keeping the effect of soft hand-over. SOLUTION: A searching inverse spread section 30 of a mobile station 1 applies inversely spreading to a pilot channel signal that is received by an antenna and comes from each base station whose propagation path differs, and a pilot reception SIR measurement section 33 measures each reception SIR. An open loop transmission power control information generating section 40 generates open loop transmission power control information for controlling the transmission power of a traffic channel signal from each base station depending on a measured level of each pilot channel signal reception SIR. A modulation section 43 modulates the open loop transmission power control information generated by the open loop transmission power control information generating section 40. A transmission section 44 sends the generated open the loop transmission power control information to each base station.

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 controlling transmission power in communication using DS / CDMA, and more particularly to a mobile communication system for increasing system capacity in downlink transmission power control during execution of soft handover. It is related to technology that is effective when applied to

[0002]

2. Description of the Related Art Conventional DS / CDMA (Direct)
Sequence / Code Division Mul
When a mobile station moves from a specific cell to another cell in a mobile communication system using “type Access”, the mobile station switches channels after performing communication simultaneously with the source base station and the destination base station. Soft handover is taking place.

In a mobile communication system, the downlink is composed of a pilot channel and a traffic channel, and a pilot channel signal is constantly transmitted at a constant transmission power, while a traffic channel signal is transmitted only by performing transmission power control during communication. . Since the DS / CDMA mobile communication system is a communication method using the same frequency band between adjacent cells, the mobile station can perform soft handover in which communication is performed with a plurality of base stations at the same time and then handover is performed.

FIG. 10 is a diagram showing a schematic configuration of a soft handover using a conventional cell configuration. As shown in FIG. 10, the conventional CDMA mobile communication system includes a mobile station 1 and
And base stations 21 to 23.

[0005] The mobile station 1 is a terminal device that switches channels with the base stations 21 to 23 while moving. Base station 21
23 are devices for controlling communication of the mobile station 1 in the cell.

[0006] The mobile station 1 receives a pilot channel signal and receives a signal to signal (SIR).
e Ratio) or the base station 21 and the base station 22 are selected from the adjacent base stations in descending order of the received power, and the selected base station 21 and the base station 2 are selected.
2 and communicate simultaneously.

[0007] In a DS / CDMA mobile communication system, by performing soft handover, channel switching during inter-cell movement can be performed without an instantaneous interruption, and communication quality can be improved by combining communication signals having different propagation paths. Can be improved.

[0008] Regarding the transmission power control method when performing the soft handover, see, for example, "Downlink capacity of DS / CDMA system using soft handover", Kenro Hamabe, Naomasa Yoshida, IEICE, Society Conference, Communications Society Conference Lecture Papers, PP. 3
66-367, 1995.

In the above transmission power control method, the transmission power Tx1_power of each base station with respect to the mobile station 1 when the mobile station 1 is communicating with the adjacent base station 21 and base station 22.
r and Tx2_power are equal to each other.

In the transmission power control method, the mobile station 1
Controls the transmission power so that the combined signal of the traffic channel signals received from each base station has the required SIR required to obtain a certain communication quality.

Here, the mobile station 1 has three or more base stations 21.
Similarly, when communicating with mobile stations 1 through 23, the transmission power of each base station to mobile station 1 is assumed to be equal, and such a control method is called an equal transmission power method.

FIG. 11 is a diagram showing a breakdown of the received power of the mobile station when soft handover is performed in the conventional equal transmission power method. FIG. 11 shows the breakdown of the received power of the mobile station when the mobile station 1 executes soft handover with the base stations 21 and 22 of the two adjacent stations by the same transmission power method, and the width is the transmission of each base station. The power and the height represent the attenuation rate normalized by the interference power, and the product area is the reception S at the mobile station 1.
It corresponds to IR.

When the mobile station 1 is performing soft handover with the adjacent base station 21 and base station 22, the transmission power of each base station to the mobile station 1 is equal in the equal transmission power method, and the following relationship is established.

[0014]

Tx1_power = Tx2_power Further, the reception SIR at the mobile station 1 after the combination becomes the required SIR (SIR_req) due to the transmission power control, and thus has the following relationship.

[0015]

SIR_req = Rx1_SIR + Rx2_SIR From these two relational expressions, in the equal transmission power method, transmission power control is performed so that the following expression is finally satisfied.

[0016]

Tx1_power = SIR_req / (path1 + path2) = Tx2_power

[0017]

In the downlink of a mobile communication system using DS / CDMA, the system capacity can be increased by reducing the transmission power or interference power from the base station. In the transmission power control method described above, since each base station transmits to a mobile station located outside the cell with equal power, there is a problem that interference power increases and it is difficult to increase system capacity.

An object of the present invention is to solve the above-mentioned problem and to provide a technique capable of increasing the system capacity while maintaining the effect of soft handover and reducing interference with adjacent cells.

Another object of the present invention is to provide a technique capable of reducing information required for transmission power control.

[0020]

SUMMARY OF THE INVENTION The present invention relates to a transmission power control method for controlling transmission power when a soft handover is performed between a mobile station and a plurality of base stations. The transmission power of the traffic channel signal from each base station is controlled according to the magnitude of the signal reception SIR.

According to the transmission power control method of the present invention, when performing soft handover between a mobile station and a plurality of base stations, the mobile station first receives SIRs of reference signals transmitted from the plurality of base stations. Measure.

Next, open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station is generated according to the magnitude of the measured reference signal reception SIR. For example, open-loop transmission power control information of each base station is generated such that transmission power proportional to the magnitude of each reference signal reception SIR is set.

Using the generated open-loop transmission power control information, the transmission power of a traffic channel signal transmitted from each base station to the mobile station is set, and the traffic channel signal transmitted from each base station to the mobile station is set. Send.

As described above, according to the transmission power control method of the present invention, the transmission power from each base station is controlled in accordance with the reference signal reception SIR at the mobile station, so that the mobile station located outside the cell is controlled. The transmission power of the base station with respect to the station can be reduced, and the transmission power can be increased for a mobile station having poor communication quality located near the cell boundary. For this reason, while maintaining the effect of soft handover that allows inter-cell movement without interruption,
The system capacity can be increased by reducing the interference to the neighboring cells.

In the transmission power control method of the present invention, in addition to the transmission power control based on the open loop transmission power control information,
Transmission power control based on closed-loop transmission power control information may be performed.

That is, first, a traffic channel signal is transmitted from each base station to the mobile station using the open loop transmission power control information, and then the traffic channel signals transmitted from a plurality of base stations are combined. The received SIR is measured at the mobile station.

Next, closed-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station is generated in accordance with the magnitude of the measured traffic channel signal reception SIR. The transmission power of the traffic channel signal from each base station is controlled using the control information.

If the closed-loop transmission power control information is set smaller than the open-loop transmission power control information and the closed-loop transmission power control is repeated a specified number of times, and then the open-loop transmission power control is performed, good transmission power control can be achieved. And information required for transmission power control can be reduced.

As described above, according to the mobile communication system of the present invention, the transmission power from each base station is controlled according to the magnitude of the reference signal reception SIR at the mobile station, so that the effect of soft handover is maintained. In addition, it is possible to increase the system capacity by reducing interference with adjacent cells.

[0030]

(Embodiment 1) A mobile communication system according to Embodiment 1 in which downlink transmission power control during execution of soft handover is performed by open-loop transmission power control proportional to pilot channel signal reception SIR will be described below. explain.

FIG. 1 is a diagram showing the breakdown of the mobile station received power according to the present embodiment. FIG. 1 shows that a mobile station 1 is a base station 2 of two adjacent stations.
1 and the mobile station reception power when communicating with the base station 22. The width indicates the transmission power from each base station,
The height represents an attenuation rate taking into account the influence of interference power, and the product area is equivalent to the reception SIR at the mobile station 1.

In the mobile communication system of this embodiment, when the mobile station 1 is performing soft handover with the two base stations 21 and 22, the transmission power of the traffic channel signal to the mobile station 1 of each base station Tx1_power
r and Tx2_power are Rx_Pilot1_SI, which are pilot channel signal reception SIRs at the mobile station 1.
R is proportional to Rx_Pilot2_SIR and has the following relationship.

[0033]

Tx1_power: Tx2_power =
Rx_Pilot1_SIR: Rx_Pilot2_
SIR Further, the received SIR at the mobile station 1 after combining the traffic channel signals from the base station 21 and the base station 22 becomes a required SIR (SIR_req) due to transmission power control, and thus has the following relationship.

[0034]

SIR_req = Rx1_SIR + Rx2_SIR From these two relational expressions, the transmission power Tx1_power
And Tx2_power are distributed as follows.

[0035]

Tx1_power = (SIR_req ×
path1) / (path1 2 + path2 2) Tx2_power = (SIR_req × path
2) / (path1 2 + path2 2 ) Hereinafter, when a part of Expression 6 is expressed as Expression 7,
(A) and (B) show Rx_Pilo measured by the mobile station 1.
This is represented by Expression 8 by t1_SIR and Rx_Pilot2_SIR.

[0036]

[Equation 7] path1 / (path1 2 + path2 2 ) = (A) path2 / (path1 2 + path2 2) = (B)

[0037]

(A) = Rx_Pilot1_SIR / (Rx
_Pilot1_SIR 2 + Rx_Pilot2_SI
R 2 ) (B) = Rx_Pilot2_SIR / (Rx_Pil)
ot1_SIR 2 + Rx_Pilot 2_SIR 2 ) In the mobile communication system of the present embodiment, the mobile station 1 notifies the base station 21 and the base station 22 of (A) and (B) as open-loop transmission power control information using the uplink traffic channel. , The base station 21 and the base station 22 transmit power Tx1_power and Tx2_power based on the information.
control r.

FIG. 2 is a diagram showing functional blocks of the mobile station 1 of the present embodiment. As shown in FIG. 2, the mobile station 1 according to the present embodiment includes a search despreading unit 30, traffic despreading units 31 and 32, a pilot reception SIR measurement unit 33,
It has a base station selector 34, a diversity combiner 35, an open-loop transmission power control information generator 40, a modulator 43, and a transmitter 44.

The search despreading unit 30 is a circuit for despreading the pilot channel signal of each base station. The traffic despreading units 31 and 32 are circuits for despreading the traffic channel signal of each base station. Pilot reception SIR
The measurement unit 33 is a circuit that measures the reception SIR of the pilot channel signal, which is the reference signal transmitted from the plurality of base stations 21 to 23.

The base station selecting section 34 is a circuit for selecting a base station having a reception SIR equal to or more than a predetermined threshold value from adjacent base stations. The diversity combining unit 35 is a circuit that combines the traffic channel signals of the selected adjacent base stations.

The open-loop transmission power control information generation section 40 generates the open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station according to the magnitude of the measured pilot channel signal reception SIR. It is a circuit generated by

The modulator 43 is a circuit for modulating the open-loop transmission power control information generated by the open-loop transmission power control information generator 40. The transmission unit 44 is a circuit that transmits the generated open-loop transmission power control information to each base station.

FIG. 2 shows adjacent base stations 21 and 22
Represents a functional block of the mobile station 1 for generating open-loop transmission power control information for performing downlink transmission power control when performing soft handover with the base station, and transmitting the generated information to each base station.
As shown in FIG. 2, the mobile station 1 includes a CPU for controlling the operation of the entire mobile station 1, a memory for storing programs and data for controlling the entire operation of the mobile station 1, and a display device for displaying an operation state. And an input device for inputting operation contents, and a digital signal processor (DSP) for controlling communication processing with the base stations 21 to 23.

FIG. 3 shows the pilot reception SIR of this embodiment.
FIG. 3 is a diagram illustrating functional blocks of a measurement unit 33 and an open-loop transmission power control information generation unit 40. As shown in FIG.
Measures the reception SIR of the pilot channel signal transmitted from each base station, and controls the transmission power of the traffic channel signal of each base station in accordance with the measured reception SIR. Generate

In mobile station 1, search despreading section 30 despreads pilot channel signals received from an antenna from base stations having different propagation paths, and despreads the respective received SIRs.
Is measured by the pilot reception SIR measurement unit 33.

The base station selecting section 34 selects two stations having a reception SIR equal to or higher than a predetermined threshold, for example, the base station 21 and the base station 22, and selects those base stations 21 and 22.
2 and perform soft handover.

The open-loop transmission power control information generating section 40 uses the circuit shown in FIG. 3 to calculate the open-loop transmission power control information for the base station 21 shown in Equation 8 = (A) the open-loop transmission power control information for the base station 22 = (B) is calculated, spread-modulated together with transmission data using an uplink traffic channel, and then transmitted to each base station.

The traffic channel signals received from the base station 21 and the base station 22 are despread by the traffic despreading units 31 and 32, respectively, and the diversity combining unit 35 combines and combines the phases of the branches.

Here, when the mobile station 1 executes soft handover with three or more adjacent base stations 21 to 23, similarly, the open loop transmission power control is performed in each base station and the traffic channel from each base station is controlled. This can be easily realized by diversity combining the signals.

FIG. 4 is a diagram showing functional blocks of the base station 21 of the present embodiment. As shown in FIG. 4, the base station 21 of the present embodiment includes a traffic despreading unit 51, an open-loop transmission power control unit 53, a modulation unit 55, a transmission unit 56, and a demodulation unit 57. I have.

The traffic despreading section 51 is a circuit for despreading the traffic channel signal received from the mobile station 1. The open-loop transmission power control unit 53 controls the reception SI of the pilot channel signal transmitted from the base station 21 at the mobile station 1.
A circuit for controlling the transmission power of the traffic channel signal using the open loop transmission power control information generated according to R.

The modulation section 55 is a circuit for modulating downlink transmission data. The transmission unit 56 is a circuit that transmits a downlink traffic channel signal to the mobile station 1 with the transmission power set by the open-loop transmission power control unit 53. The demodulation unit 57 is a circuit for demodulating the despread traffic channel signal.

FIG. 4 corresponds to FIG. 2 and shows functional blocks of the base station 21 which performs downlink transmission power control by open-loop transmission power control when performing soft handover between the mobile station 1 and an adjacent base station. As shown in FIG. 4, the base station 21 includes a CPU that controls the operation of the entire base station 21,
A memory for storing programs and data for controlling the operation of the entire base station 21; an input device for inputting operation contents; a mobile communication exchange I / F for connecting the base station 21 to the mobile communication exchange; A digital signal processor (DSP) for controlling communication processing with the station 1;

Base station 21 despreads and demodulates the traffic channel signal received from mobile station 1 in traffic despreading section 51. Based on the open loop transmission power control information notified from the mobile station 1 included in the demodulated data,
The open-loop transmission power control unit 53 updates the transmission power for the mobile station 1 and transmits downlink transmission data using a traffic channel.

The base station 22 has the same function as the base station 21, updates the transmission power for the mobile station 1, and transmits downlink transmission data using a traffic channel. Even when the mobile station 1 performs soft handover with three or more adjacent base stations 21 to 23, each base station can be realized by similar functional blocks.

FIG. 5 is a diagram showing an outline of the position of the mobile station 1 and the transmission power of the base station 21 during execution of soft handover according to the present embodiment. FIG. 5 shows that the mobile station 1 has two adjacent base stations 21 and 2 in the mobile communication system of the present embodiment.
FIG. 5 shows the relationship between the position of the mobile station 1 and the transmission power of the base station 21 when the transmission power is controlled so that the reception SIR satisfies the required SIR under the ideal condition 2 and FIG.
, The horizontal axis is the position of the mobile station 1 with respect to the base station 21 or the base station 22, the vertical axis is the transmission power of the base station 21, the solid line is the plot result of the mobile communication system of the present embodiment, and the dotted line is the conventional equal transmission power method. 2 shows the plotting result. The vertical line in the center of FIG. 5 indicates the cell boundary between the base station 21 and the base station 22.

As shown in FIG. 5, in the conventional equal transmission power method, the transmission power of the base station 21 is larger than that of the mobile station 1 located outside the cell of the base station 21, but in the mobile communication system of this embodiment, The transmission power from the base station 21 to the mobile station 1 located outside the cell of the base station 21 is reduced, so that the mobile station 1 of poor communication quality located near the cell boundary in the cell of the base station 21 It can be seen that the transmission power from 21 is increased.

In the mobile communication system according to the present embodiment,
Although each value indicated by the open loop transmission power control information transmitted to the base station 21 and the base station 22 has been described as being proportional to each pilot channel signal reception SIR at the mobile station 1,
The value indicated by the open-loop transmission power control information transmitted to the base station transmitting the pilot channel signal having a high reception SIR is equal to the value of the open-loop transmission power control transmitted to the base station transmitting the pilot channel signal having a low reception SIR. Another value that is higher than the value indicated by the information may be used. That is, other values that fluctuate similarly to the reception SIR can be used, for example, the reception SIR of the pilot channel signal.
Instead, the same transmission power control can be performed by using the reception power. The same applies to the following embodiments.

As described above, according to the mobile communication system of the present embodiment, the transmission power from each base station is controlled in accordance with the magnitude of the reference signal reception SIR at the mobile station. It is possible to increase the system capacity while maintaining the above, and reducing the interference to the adjacent cells.

(Second Embodiment) A mobile communication system according to a second embodiment in which downlink transmission power control during soft handover is performed by open-loop transmission power control and closed-loop transmission power control will be described below.

In the open-loop transmission power control in the mobile communication system of the present embodiment, the transmission power Tx1_power is obtained by averaging the pilot channel signal reception SIR in the mobile station 1 for a sufficiently long time and generating open-loop transmission power control information.
Control is performed so that r and Tx2_power become the median of the transmission power control range.

On the other hand, in the closed-loop transmission power control of the mobile communication system of the present embodiment, when the traffic channel signal reception SIR at the mobile station 1 is equal to or less than the required SIR, the transmission power Tx1_power and Tx2_power from each base station.
er is increased by a certain width, and when the required SIR is exceeded, a control is performed to lower it by a certain width.

FIG. 6 is a diagram showing the breakdown of the mobile station received power according to the present embodiment. FIG. 6 shows the breakdown of the reception power of the mobile station 1 when the open-loop transmission power control and the closed-loop transmission power control are performed in the mobile communication system of the present embodiment. First, as shown in FIG. Using open loop transmission power control to determine the median of the transmission power control range of each base station,
The transmission power of the downlink traffic channel signal is distributed to each base station.

In FIG. 6 (2), using the closed-loop transmission power control, control is performed to raise or lower the transmission power of the traffic channel signal from each base station by a fixed width based on the closed-loop transmission power control information. As shown in 3) and (4), the closed loop transmission power control is repeated for a certain period.

Returning to FIG. 6A, the central value of the transmission power control range is updated using open-loop transmission power control, and the transmission power of the downlink traffic channel signal is redistributed for each base station. The above operation is repeated.

FIG. 7 is a diagram showing functional blocks of the mobile station 1 of the present embodiment. As shown in FIG. 7, the mobile station 1 according to the present embodiment includes a traffic reception SIR measurement unit 36 and a closed loop transmission power control information generation unit 41.

The traffic reception SIR measuring unit 36 is a circuit for measuring the reception SIR of the traffic channel signal after the diversity combining of the traffic channel signals transmitted from the plurality of base stations 21 and 22. The closed-loop transmission power control information generation unit 41 compares the measurement result of the traffic reception SIR measurement unit 36 with the required SIR, and if the measured value is larger than the required SIR, the closed-loop transmission power control information for reducing the transmission power by a certain width. Is a circuit for generating closed-loop transmission power control information for increasing the transmission power by a certain width.

FIG. 7 shows the adjacent base station 21 and base station 22.
Mobile station 1 that generates open-loop transmission power control information and closed-loop transmission power control information for performing downlink transmission power control when performing soft handover with
The other configuration of the mobile station 1 is the same as that shown in the first embodiment.

The mobile station 1 despreads the pilot channel signals received from the antennas of the respective base stations having different propagation paths by the search despreading unit 30, and the pilot channel signal reception SIRs by the pilot reception SIR measurement unit 33. Measure.

The base station selector 34 selects base stations 21 and 22 having reception SIRs equal to or higher than a predetermined threshold value.
And the like, and their base stations 21 and 22 are selected.
And perform soft handover.

The open loop transmission power control information generation section 40
Similar to the mobile station 1 of the first embodiment, open-loop transmission power control information for the base station 21 = (A) Open-loop transmission power control information for the base station 22 = (B) is calculated. The system generates open-loop transmission power control information using the received SIRs that are sufficiently averaged compared to the first embodiment.

The traffic despreading units 31 and 32 despread the traffic channel signals received from each base station, respectively, and the diversity combining unit 35 combines the paths by matching the phases of the paths.

The traffic reception SIR measuring section 36 measures the traffic channel signal reception SIR after the diversity combining, and the closed loop transmission power control information generation section 41 compares the result with the required SIR. If the power is less than the required SIR, closed-loop transmission power control information for reducing the power by a certain width is generated.

The open-loop transmission power control information and the closed-loop transmission power control information are transmitted to the base station 21 and the base station 22 using the uplink traffic channel after the spread modulation.

FIG. 8 is a diagram showing functional blocks of the base station 21 of the present embodiment. FIG. 8 corresponds to FIG. 7 and illustrates a case where the base station 21 performs downlink transmission power control by open-loop transmission power control and closed-loop transmission power control when performing soft handover between the mobile station 1 and an adjacent base station. It shows a functional block, and the other configuration of the base station 21 is the same as that shown in the first embodiment.

Base station 21 despreads and demodulates the traffic channel signal received from mobile station 1 in traffic despreading section 51. The demodulated data includes the open loop transmission power control information or the closed loop transmission power control information notified from the mobile station 1.

When the open-loop transmission power control information is notified, the open-loop transmission power control unit 53 updates the transmission power to the mobile station 1 so that it becomes the median value of the notified transmission power control range. When the closed loop transmission power control information is notified, the closed loop transmission power control unit 54 increases or decreases the transmission power to the mobile station 1 by a certain width.

The base station 22 has a function similar to that of the base station 21 and performs transmission power control on the mobile station 1 in the same manner. Further, when the mobile station 1 performs soft handover with three or more adjacent base stations 21 to 23, each base station can be realized by the same function.

As described above, the mobile communication system according to the present embodiment generates the open-loop transmission power control information using the reception SIRs which are sufficiently averaged as compared with the first embodiment. After performing the power control 100 times, the received SIR during that time is averaged to generate open-loop transmission power control information.

As shown in the first embodiment, when only the open-loop transmission power control is used and, for example, 8-bit open-loop transmission power control information is transmitted every 1 msec to perform the open-loop transmission power control, the transmission is performed. In order to perform power control, a band corresponding to a voice channel is required.

Thus, as in the mobile communication system of the present embodiment, for example, after transmitting 1-bit closed-loop transmission power control information indicating only upper and lower transmission power every 1 msec and performing closed-loop transmission power control 100 times, By transmitting 8-bit open-loop transmission power control information indicating the median value of the transmission power control range to perform open-loop transmission power control,
It is possible to perform good transmission power control and reduce information for performing transmission power control.

On the other hand, the downlink transmission power control combining the open loop and the closed loop shown in the mobile communication system of the present embodiment may be used other than during the execution of the soft handover. Hereinafter, downlink transmission power control combining open loop and closed loop when soft handover is not performed will be described.

In the open-loop transmission power control method when the soft handover is not performed, the reception SIR of the pilot channel signal of the mobile station 1 is averaged for a sufficiently long time when communicating with one base station 21 to generate open-loop transmission power control information. By doing so, control is performed so that the transmission power Tx1_power becomes the center value of the transmission power control range.

On the other hand, in the closed loop transmission power control method when soft handover is not performed, the transmission power Tx1_power of the base station 21 is increased by a certain width when the reception SIR of the traffic channel signal is equal to or less than the required SIR, and is increased when the reception SIR exceeds the required SIR. Control to decrease the width.

FIG. 9 is a diagram showing a breakdown of the received power of the mobile station when soft handover is not executed according to the present embodiment. FIG.
In the mobile communication system of the present embodiment, when soft handover is not performed, the mobile station reception power when a specific base station distributes transmission power to a plurality of mobile stations using open loop transmission power control and closed loop transmission power control is used. First, as shown in FIG. 9A, the median value of the transmission power control range of the base station is determined using open-loop transmission power control.

Next, in FIG. 9 (2), using the closed-loop transmission power control, control is performed to increase or decrease the transmission power of the traffic channel signal from each base station by a fixed width based on the closed-loop transmission power control information. As shown in (3) and (4), the closed loop transmission power control is repeated for a certain period.

Returning to FIG. 9 (1), the median value of the transmission power control range is updated using open-loop transmission power control, and the transmission power of the downlink traffic channel signal of the base station is updated for each of a plurality of mobile stations. After the distribution, the above operation is repeated.

In the open-loop transmission power control in the mobile communication system of the present embodiment, the median of the transmission power control range is generated as the open-loop transmission power control information, but other values other than the median may be used. . For example, it is conceivable to generate the upper limit, lower limit, or average transmission power value as the transmission power control information.

As described above, according to the mobile communication system of the present embodiment, the transmission power from each base station is controlled in accordance with the magnitude of the reference signal reception SIR at the mobile station. It is possible to increase the system capacity while maintaining the above, and reducing the interference to the adjacent cells.

Further, according to the mobile communication system of the present embodiment, since the transmission power from each base station is controlled by the open-loop transmission power control and the closed-loop transmission power control, it is possible to reduce information necessary for the transmission power control. It is possible.

[0091]

According to the present invention, the transmission power from each base station is controlled in accordance with the magnitude of the reference signal reception SIR at the mobile station. It is possible to increase the system capacity by reducing the interference.

[Brief description of the drawings]

FIG. 1 is a diagram showing a breakdown of mobile station received power according to a first embodiment.

FIG. 2 is a diagram illustrating functional blocks of a mobile station 1 according to the first embodiment.

FIG. 3 shows a pilot reception SIR measurement unit 33 according to the first embodiment.
3 is a diagram showing functional blocks of an open-loop transmission power control information generation unit 40. FIG.

FIG. 4 is a diagram illustrating functional blocks of a base station 21 according to the first embodiment.

FIG. 5 is a diagram illustrating an outline of a position of a mobile station 1 and transmission power of a base station 21 during execution of soft handover according to the first embodiment.

FIG. 6 is a diagram illustrating a breakdown of mobile station reception power according to a second embodiment.

FIG. 7 is a diagram illustrating functional blocks of a mobile station 1 according to a second embodiment.

FIG. 8 is a diagram illustrating functional blocks of a base station 21 according to a second embodiment.

FIG. 9 is a diagram illustrating a breakdown of mobile station reception power when a soft handover is not performed according to the second embodiment.

FIG. 10 is a diagram showing a schematic configuration of soft handover using a conventional cell configuration.

FIG. 11 is a diagram showing a breakdown of mobile station reception power when a soft handover is performed in the conventional equal transmission power method.

[Explanation of symbols]

30: Search despreading unit, 31 and 32: Traffic despreading unit, 33: Pilot reception SIR measuring unit, 34 ...
Base station selection unit, 35: diversity combining unit, 40: open-loop transmission power control information generation unit, 43: modulation unit, 44: transmission unit, 51: despreading unit for traffic, 53: open-loop transmission power control unit, 55 ... Modulation section, 56 transmission section, 57 demodulation section, 36 traffic reception SIR measurement section, 41 closed loop transmission power control information generation section, 54 closed loop transmission power control section, 1 mobile station, 21 to 23 base Bureau.

Claims (12)

[Claims]
1. A transmission power control method for controlling transmission power when performing soft handover between a mobile station and a plurality of base stations, comprising: moving a reception SIR of a reference signal transmitted from the plurality of base stations. Station, and generates open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station in accordance with the magnitude of each of the measured reference signal reception SIRs. A transmission power control method comprising controlling transmission power of a traffic channel signal from each base station using transmission power control information.
2. A transmission power control method for controlling transmission power when performing a soft handover between a mobile station and a plurality of base stations, comprising: moving a reception SIR of a reference signal transmitted from the plurality of base stations. Station, and generates open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station in accordance with the magnitude of each of the measured reference signal reception SIRs. The transmission power of the traffic channel signal from each base station is set using the transmission power control information, the received SIR after combining the traffic channel signals transmitted from a plurality of base stations is measured by the mobile station, and from each base station, Generating closed loop transmission power control information for controlling the transmission power of the traffic channel signal according to the measured traffic channel signal reception SIR, Transmission power control method characterized by controlling the transmission power of the traffic channel signal from each base station using a closed loop transmission power control information serial generated.
3. The transmission power control method according to claim 1, wherein the open-loop transmission power control information is proportional to each of the measured reference signal reception SIRs. .
4. A mobile communication system that performs soft handover between a mobile station and a plurality of base stations, wherein a reference signal reception SIR measurement unit that measures reception SIRs of reference signals transmitted from the plurality of base stations is provided. The open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station by the measured reference signal reception SI
An open-loop transmission power control information generation unit that generates the open-loop transmission power control information according to the magnitude of R; and an open-loop transmission power control that controls the transmission power of the traffic channel signal from each base station using the generated open-loop transmission power control information. A mobile communication system comprising: a transmission unit configured to transmit a traffic channel signal to the mobile station with the transmission power set by the open-loop transmission power control unit.
5. A mobile communication system for performing soft handover between a mobile station and a plurality of base stations, a reference signal reception SIR measuring unit for measuring reception SIRs of reference signals transmitted from the plurality of base stations. The open-loop transmission power control information for controlling the transmission power of the traffic channel signal from each base station by the measured reference signal reception SI
An open-loop transmission power control information generation unit that generates the transmission power control information based on the size of R, and an open-loop transmission power control that controls the transmission power of the traffic channel signal from each base station using the generated open-loop transmission power control information Unit, a traffic reception SIR measuring unit for measuring a reception SIR after combining traffic channel signals transmitted from a plurality of base stations, and a closed-loop transmission power control for controlling the transmission power of the traffic channel signal from each base station A closed-loop transmission power control information generating unit for generating information in accordance with the measured traffic channel signal reception SIR, and using the generated closed-loop transmission power control information to calculate the transmission power of the traffic channel signal from each base station. A closed-loop transmission power control unit for controlling; an open-loop transmission power control unit and a closed-loop transmission power control unit. Mobile communication system, comprising a transmitter which in the set transmission power to transmit the traffic channel signal to the mobile station.
6. The mobile communication system according to claim 4, wherein the open loop transmission power control information is proportional to each of the measured reference signal reception SIRs.
7. A mobile station executing soft handover with a plurality of base stations, a reference signal reception SIR measuring unit for measuring a reception SIR of a reference signal transmitted from the plurality of base stations, and each base station The open loop transmission power control information for controlling the transmission power of the traffic channel signal from the
A mobile station, comprising: an open-loop transmission power control information generation unit that generates according to the magnitude of R; and a transmission unit that transmits the generated open-loop transmission power control information to each base station.
8. A mobile station that performs soft handover between a mobile station and a plurality of base stations, wherein a reference signal reception SIR measurement unit that measures reception SIRs of reference signals transmitted from the plurality of base stations, Open loop transmission power control information for controlling the transmission power of a traffic channel signal from each base station is measured for each reference signal reception SI.
An open-loop transmission power control information generation unit that generates according to the size of R; a traffic reception SIR measurement unit that measures a reception SIR after combining traffic channel signals transmitted from a plurality of base stations; A closed-loop transmission power control information generator for generating closed-loop transmission power control information for controlling the transmission power of the traffic channel signal according to the measured traffic channel signal reception SIR; and the generated open-loop transmission power. A transmission unit for transmitting control information or closed-loop transmission power control information to each base station.
9. The mobile station according to claim 7, wherein the open loop transmission power control information is proportional to each of the measured reference signal reception SIRs.
10. A base station that performs soft handover with a plurality of base stations, the mobile station receiving a reference signal transmitted from the base station.
An open-loop transmission power control unit for controlling the transmission power of the traffic channel signal using the open-loop transmission power control information generated in accordance with the IR; and the mobile station with the transmission power set by the open-loop transmission power control unit. A transmission unit for transmitting a traffic channel signal to the base station.
11. A base station that performs soft handover with a plurality of base stations, wherein the base station controls transmission power of a traffic channel signal from each base station using the generated open-loop transmission power control information. A loop transmission power control unit, a closed loop transmission power control unit that controls transmission power of a traffic channel signal from each base station using the generated closed loop transmission power control information, the open loop transmission power control unit, and a closed loop transmission power. A transmission unit configured to transmit a traffic channel signal to the mobile station with the transmission power set by the control unit.
12. The base station according to claim 10, wherein the open loop transmission power control information is proportional to each of the measured reference signal reception SIRs.
JP10683698A 1998-04-17 1998-04-17 Transmission power control method at the time of executing soft handover and apparatus for implementing the method Expired - Lifetime JP3343214B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10683698A JP3343214B2 (en) 1998-04-17 1998-04-17 Transmission power control method at the time of executing soft handover and apparatus for implementing the method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10683698A JP3343214B2 (en) 1998-04-17 1998-04-17 Transmission power control method at the time of executing soft handover and apparatus for implementing the method

Publications (2)

Publication Number Publication Date
JPH11308655A true JPH11308655A (en) 1999-11-05
JP3343214B2 JP3343214B2 (en) 2002-11-11

Family

ID=14443807

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10683698A Expired - Lifetime JP3343214B2 (en) 1998-04-17 1998-04-17 Transmission power control method at the time of executing soft handover and apparatus for implementing the method

Country Status (1)

Country Link
JP (1) JP3343214B2 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045296A1 (en) * 2000-11-29 2002-06-06 Matsushita Electric Industrial Co., Ltd. Radio infrared apparatus
WO2004030304A1 (en) * 2002-09-30 2004-04-08 Utstarcom (China) Co., Ltd. A open loop power control method for downlink common channels in cdma system
JP2010051034A (en) * 2002-04-03 2010-03-04 Nec Corp Cellular system, communication control method, and base station and mobile station therefor
EP2009818A3 (en) * 2007-06-25 2010-06-02 Fujitsu Ltd. Reception quality measurement method, transmission power control method and devices thereof
JP2012019541A (en) * 2011-09-15 2012-01-26 Hitachi Ltd Transmission power control method of wireless communications system
EP2458911A2 (en) 2010-11-30 2012-05-30 Nec Corporation Reference signal collision detection
US8228866B2 (en) 2002-04-03 2012-07-24 Nec Corporation High-speed downlink packet access system, base station, mobile station, and communication control method during a soft handover

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045296A1 (en) * 2000-11-29 2002-06-06 Matsushita Electric Industrial Co., Ltd. Radio infrared apparatus
US7266096B2 (en) 2000-11-29 2007-09-04 Matsushita Electric Industrial Co., Ltd. Radio infrastructure apparatus
JP2010051034A (en) * 2002-04-03 2010-03-04 Nec Corp Cellular system, communication control method, and base station and mobile station therefor
US8228866B2 (en) 2002-04-03 2012-07-24 Nec Corporation High-speed downlink packet access system, base station, mobile station, and communication control method during a soft handover
WO2004030304A1 (en) * 2002-09-30 2004-04-08 Utstarcom (China) Co., Ltd. A open loop power control method for downlink common channels in cdma system
US7830818B2 (en) 2007-06-25 2010-11-09 Fujitsu Limited Reception quality measurement method, transmission power control method and devices thereof
EP2320583A1 (en) * 2007-06-25 2011-05-11 Fujitsu Limited Reception quality measurement method, transmission power control method and devices thereof
EP2009818A3 (en) * 2007-06-25 2010-06-02 Fujitsu Ltd. Reception quality measurement method, transmission power control method and devices thereof
EP2458911A2 (en) 2010-11-30 2012-05-30 Nec Corporation Reference signal collision detection
CN102547790A (en) * 2010-11-30 2012-07-04 日本电气株式会社 Reference signal collision detection
US8737195B2 (en) 2010-11-30 2014-05-27 Nec Corporation Reference signal collision detection
JP2012019541A (en) * 2011-09-15 2012-01-26 Hitachi Ltd Transmission power control method of wireless communications system

Also Published As

Publication number Publication date
JP3343214B2 (en) 2002-11-11

Similar Documents

Publication Publication Date Title
Ariyavisitakul et al. Signal and interference statistics of a CDMA system with feedback power control
US6233456B1 (en) Method and apparatus for adjacent coverage area handoff in communication systems
AU753917B2 (en) Downlink power control in a cellular mobile radio communications system
EP1377100B1 (en) Method and apparatus for reducing the average downlink transmitted power from base stations during soft handoff
EP1733583B1 (en) Mobile communications in a hierarchical cell structure
JP4416820B2 (en) Multiple I / O communication method based on distributed transmission source
ES2208684T3 (en) Procedure and apparatus for balancing the call transfer limit of the direct link with the call transfer limit of the invested link in a cellular telecommunications system.
US6078817A (en) System and method of dynamically increasing the capacity of a code division multiple access radio telecommunications network
US6930470B2 (en) System and method for code division multiple access communication in a wireless communication environment
EP0762668B1 (en) Method for controlling transmission power of a radio transmitter
KR100764925B1 (en) Power control in radio system
EP2165430B1 (en) Setting maximum power at a mobile communication system base station having multiple antennas
CA2211925C (en) Downlink transmission power control scheme for mobile communication system using site diversity
US6600933B1 (en) Transmission diversity method
US6985466B1 (en) Downlink signal processing in CDMA systems utilizing arrays of antennae
US5828661A (en) Method and apparatus for providing a cone of silence in a cellular communication system
Ariyavisitakul SIR-based power control in a CDMA system
US5878350A (en) Scheme for controlling transmission powers during soft handover in a CDMA mobile communication system
US5926470A (en) Method and apparatus for providing diversity in hard handoff for a CDMA system
KR100436322B1 (en) Communication control method in mobile communication system and base station used therefor
DE60100882T2 (en) Method and base station for locating upstream interference from other cells and initiating handover in a wireless network
TW391094B (en) Initial transmit power determination a radiocommunication system
JP3343908B2 (en) Broadcast communication method and system, base station apparatus and mobile station
US6845244B2 (en) Directivity control type communication apparatus and adaptive array antenna apparatus
KR100235855B1 (en) Method of controlling transmitted power of cdma system and base station using this method

Legal Events

Date Code Title Description
FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20070823

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20080823

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20080823

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090823

Year of fee payment: 7

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100823

Year of fee payment: 8

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100823

Year of fee payment: 8

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110823

Year of fee payment: 9

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120823

Year of fee payment: 10

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130823

Year of fee payment: 11

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313111

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313111

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313111

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

EXPY Cancellation because of completion of term