KR20120116146A - System and method for controlling uplink power - Google Patents

Abstract

PURPOSE: An uplink power control system and a method thereof are provided to increase uplink voice and data quality by increasing uplink power control success rate in an electric wave mixed region. CONSTITUTION: A base station controller(300) determines a PO2(power offset 2) value based on the number of wireless links set in a target base target base station(200b). The base station controller transmits a PO2 change request signal to the target base station. The target base station sets up a wireless link according to a wireless link setup request from the base station controller. The target base station transmits a response to a wireless link setup request to the base station controller. The target base station sets up PO2 value included in the PO2 change request signal as PO2 value of a downlink power control frame. [Reference numerals] (200a) First base station; (200b) Second base station; (300) Base station controller

Description

System and Method for controlling Uplink power

The present invention relates to an uplink power control system and method, and more particularly, when a base station controller receives a measurement report message from a user terminal, determines whether to perform a handover, and sets a radio link to a target base station when a handover is required. Request to receive the response, determine a PO2 (PowerOffset2) value based on the number of radio links set in the target base station, and transmit a PO2 value change request signal to the target base station; The present invention relates to an uplink power control system and method for setting a PO2 value included in the PO2 value of a downlink power control frame (TPC frame) for uplink power control.

The wireless communication system uses a power control technique as a method for reducing the inter-cell interference caused by the interference from the adjacent cell and the path loss according to the distance between the base station and the terminal.

The power control technique is a technique for adjusting the transmission power to transmit data at the lowest power level while maintaining a certain quality of service (QoS) of the wireless communication system.

1 is a view for explaining a conventional uplink power control method, Figure 2 is a view showing a general downlink power control frame structure.

Referring to FIG. 1, in uplink power control, an SINR value measured at a base station measuring a signal to interference / noise ratio (SINR) value of an uplink dedicated physical control channel (DPCCH) pilot symbol is If higher than the target SINR value, the command to lower the user terminal output using the TPC (transmission power command) of the downlink DPCCH, and if the lower than the target SINR value is commanded to increase the user terminal output. At this time, the control of the user terminal output means the control of the uplink DPCCH power, the power of the DPCCH is moved in conjunction with the DPCCH according to a specified ratio.

One DPCH 10msec frame consists of 15 slots as shown in FIG.

Uplink inner loop power control controls the level of the uplink DPCCH, while downlink inner loop power control controls the level of the downlink dedicated physical data channel (DPDCH).

The power ratios for the transport format combination information (TFCI) of the downlink DPCCH, the TPC, and the pilot symbol to the DPDCH are respectively defined by parameters of PO1 (Power Offset 1), PO2, and PO3, and are designated by the operator.

In the case of uplink inner loop power control, after comparing the SINR of the uplink DPCCH transmitted by the user terminal, it is determined whether the power up / down, and put the determined result in the power control frame of the downlink DPCCH to the user terminal send.

The transmission power value of the power control frame is determined by an offset with respect to downlink DPDCH power (hereinafter referred to as Power Offset 2, PO2), and the value may be from 0 dB to 7.75 dB.

However, in the related art, since the PO2 value determined by the operator is statically used, when the PO2 value is set low, the success rate of uplink inner loop power control is low, and when set to a high value, the surrounding user interference increases.

In addition, a transmission failure of a power control frame occurs in a mixed wave region (eg, a building) in which a plurality of radio links exist, resulting in an error in performing uplink power control, and deteriorating uplink voice and data quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to improve uplink voice and data quality by increasing the success rate of uplink power control in a mixed radio region (eg, a building) having a plurality of wireless links. It is to provide an uplink power control system and method that can be improved.

According to an aspect of the present invention, in order to achieve the above object, when a measurement report message is received from the user terminal, it is determined whether the handover, and if the handover is required to request a radio link setting to the target base station to receive the response And a base station controller for determining a PO2 value based on the number of radio links set in the target base station and transmitting a PO2 value change request signal to the target base station, and setting a radio link according to a radio link setting request from the base station controller. An uplink power including a target base station for transmitting a response to the base station controller and setting a PO2 value included in the PO2 value change request signal to a PO2 value of a downlink power control frame (TPC frame) for uplink power control A control system is provided.

The base station generates a transmit power command (TPC) message including the set PO2 value and transmits it to the user terminal, and the user terminal changes the preset PO2 value to the PO2 value to perform uplink power control.

According to another aspect of the present invention, a communication interface unit for communication with a user terminal or a base station, a base station information database in which the number of radio links for each base station is stored, and when a measurement report message is received from the user terminal through the communication interface unit, handover is performed. A handover control unit which determines whether or not a handover is required and requests a radio link setting to a target base station through the communication interface unit and receives a response; confirms the number of radio links set in the target base station from the base station information database A base station controller including a PO2 value determination unit for determining a PO2 value based on the identified number of radio links and transmitting a PO2 value change request signal to the target base station.

The PO2 value determination unit determines the PO2 value differently by dividing into two radio links and three or more radio links.

According to another aspect of the present invention, a communication interface unit for communication with a user terminal or a base station controller, when a radio link setting is requested from the base station controller through the communication interface unit, and establishes a radio link to respond to the base station When the PO2 value change request signal including the PO2 value is received from the base station controller through the radio interface setting unit for transmitting to the controller, the PO2 value of the downlink power control frame for uplink power control is received. A base station including a PO2 value setting unit for setting a value is provided.

The PO2 value setting unit generates a TPC message including the set PO2 value and transmits the generated TPC message to the user terminal.

According to another aspect of the present invention, when the base station controller receives the measurement report message from the user terminal, determining whether the handover, and if the handover is required, requesting the radio link setting to the target base station, the target base station Setting a radio link according to the radio link setting request and transmitting a response to the base station controller, wherein the base station controller determines a PO2 value based on the number of radio links set in the target base station, and includes the determined PO2 value Transmitting a PO2 value change request signal to the target base station, wherein the target base station converts the PO2 value included in the PO2 value change request signal into a PO2 value of a downlink power control frame (TPC frame) for uplink power control; And generate a transmission power command (TPC) message including the set PO2 value to the user terminal. There is provided an uplink power control method comprising the step of transmitting.

According to another aspect of the present invention, in the method for the base station controller to control the uplink power, if a measurement report message is received from the user terminal, determining whether the handover, the determination result handover is required Requesting to establish a radio link to a target base station, receiving a response, checking the number of radio links set in the target base station, determining a PO2 value based on the identified number of radio links, and including the determined PO2 value An uplink power control method comprising transmitting a PO2 value change request signal to the target base station and informing the user terminal of completion of radio link setting is provided.

According to another aspect of the present invention, in the method for the base station to control the uplink power, (a) when the PO2 value change request signal including the PO2 value is received from the base station controller, the PO2 value is uplink power Uplink power control method comprising the step of setting the PO2 value of the downlink power control frame for control, (b) generating a transmit power command (TPC) message including the set PO2 value to the user terminal; This is provided.

The uplink power control method may further include setting a radio link and transmitting a response to the base station controller when a radio link setting is requested from the base station controller.

As described above, according to the present invention, by setting the power offset value of the downlink power control frame for uplink power control differently according to the number of radio links, the success rate of uplink power control in the radio wave mixed region having a plurality of radio links. It can be increased, thereby improving uplink voice and data quality.

In addition, performance may be improved by minimizing interference of surrounding users in a mixed radio region having a plurality of wireless links.

1 is a view for explaining a conventional uplink power control method.
2 is a diagram illustrating a general downlink power control frame structure.
3 is a diagram illustrating a system for uplink power control according to the present invention;
4 is a block diagram schematically showing the configuration of a base station controller according to the present invention;
5 is a block diagram schematically showing the configuration of a base station according to the present invention;
6 illustrates an uplink power control method according to the present invention.

The foregoing and other objects, features, and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

The base station described below is referred to by various terms according to generation, such as BS (Base Station) in the second generation mobile communication, Node-B in the third generation mobile communication, and will be collectively described as a base station.

In addition, the base station controller is referred to as various terms according to generation, such as a base station controller (BSC) in the second generation mobile communication, a radio network controller (RNC) in the third generation mobile communication, and will be described below collectively as a base station controller. .

Downlink (DL) means communication from the base station to the terminal, and uplink (UL) means communication from the terminal to the base station.

3 is a diagram illustrating a system for uplink power control according to the present invention.

Referring to FIG. 3, a system for uplink power control includes a base station controller 300 for setting a PO2 value based on the number of radio links when the number of radio links increases due to a handover of the user terminal 100. Base station 200a, 200b for setting the PO2 value from 300 to the PO2 value of the downlink power control frame for uplink power control.

The user terminal 100 transmits a measurement report message to the base station controller 300 while moving from the first base station 200a to the second base station 200b. The first base station 200a may be a source base station, and the second base station 200b may be a target base station.

The user terminal 100 is handed over from the first base station 200a to the second base station 200b by the measurement report message.

Handover means that when the user terminal 100 moves out of the current communication service area and moves to an adjacent communication service area, the handover is automatically tuned to a new call channel of the adjacent communication service area to maintain a continuous call state. Say the function. That is, the user terminal 100 communicating with a specific base station is linked to a neighboring base station when the signal strength of the specific base station is weakened.

Determining the handover is performed by the base station controller 300 or the user terminal 100 by measuring parameters related to the handover trigger and transmitting a measurement report message to the base station controller 300 when a specific event occurs. The terminal 100 performs handover. Here, the event refers to a condition or event to occur to perform the handover, and the measurement report message means a message for reporting the measurement information related to the event to the base station when the event occurs.

In order to transmit a measurement report message for changing a base station, two conditions must be present. First, measurement information of a target base station is better than measurement information of a source base station, and second, the first condition is a predetermined driving time (Time to Trigger; Lasts for less than TTT).

The user terminal 100 reports the measurement result to the base station controller 300 when a periodic or specific event occurs by transmitting a measurement report message.

Various types of events are used for handover of the user terminal 100. Table 1 is an example of an event trigger message that the user terminal 100 transmits to the base station as an event occurs.

Referring to Table 1, the measurement report message regarding the occurrence of an event is a message for changing a base station which is reported when the user terminal 100 moves from a source base station to a target base station.

The following are the conditions for generating the measurement report message regarding event 1D.

First, a condition in which the measurement quality measured at the target base station around the source base station is better than that of the source base station should be satisfied, and second, this condition must be satisfied continuously for a certain driving time.

The measurement report message regarding the occurrence of the event 1E is a message for removing information from the neighboring base station from the radio link when the signal strength of the neighboring base station adjacent to the source base station becomes smaller than the threshold value. The conditions under which event 1E occurs are as follows. First, a condition where the measurement quality measured at a neighbor base station near the source base station is lower than a certain threshold must be satisfied, and second, this condition must be satisfied continuously for a certain driving time.

The measurement report message regarding the occurrence of the event 1F is a message for adding information of the neighboring base station to the radio link when the signal strength of the neighboring base station adjacent to the source base station becomes larger than the threshold value. The conditions for generating the measurement report message for the event 1F (that is, the conditions for generating the event 1F) are as follows. First, a condition where measurement quality measured at a neighbor base station around the source base station is higher than a certain threshold must be satisfied, and second, this condition must be satisfied continuously for a certain driving time.

The user terminal 100 measures the measurement information of the source base station and the measurement information of the neighbor base stations to detect the occurrence of the event described in Table 1. The measurement information means any measurable information that helps the user terminal 100 to recognize the existence of the base station, such as a signal or signal strength transmitted from the base station. As the measurement information, the power of the reference signal, the quality of the reference signal, or the block error rate of the downlink physical channel may be used.

When an event is detected, the user terminal 100 generates a measurement report message and transmits the measurement report message to the source base station. As described above, the measurement report message is a message containing various information necessary for the mobility management procedure of the user equipment 100 by the source base station, and may include not only the detection result of the event but also measurement information of the source base station and the target base station. The base station controller 300 in charge of the source base station may perform a handover upon receiving the measurement report message.

When the base station controller 300 receives the measurement report message from the user terminal 100, the base station controller 300 determines whether the handover is performed, and when the handover is required, requests the radio link setup from the second base station 200b to respond to the response. The terminal determines the PO2 value based on the number of radio links set in the second base station 200b, and transmits a PO2 value change request signal to the second base station 200b. Here, the PO2 value refers to the level of the TPC bit compared to the DPDCH. PO (PowerOffset) is a constant defined according to the frequency and the radio configuration, and refers to the up and down path attenuation compensation value according to the frequency and spreading rate.

The base station controller 300 determines whether to handover according to the event in the measurement report message. For example, when a measurement report message regarding event 1E is received, the base station controller 300 determines that a handover should be performed when the signal strength in the measurement report message is greater than a specified value, and thus a second base station that is a target base station. Request a new radio link to 210b.

In addition, when the measurement report message for event 1D is received, the base station controller 300 analyzes the measurement report message to perform handover when the measurement quality of the target base station is better than that of the source base station. In response to the determination, the second base station 210b serving as a target base station is requested to establish a new radio link.

The second base station 200b sets up a radio link according to a radio link setting request from the base station controller 300 and transmits a response to the base station controller 300, and PO2 included in the PO2 value change request signal. The value is set to the PO2 value of the downlink power control frame for uplink power control.

Then, the second base station 200b generates a transmit power command (TPC) message including the set PO2 value and transmits it to the user terminal 100.

Then, the user terminal 100 performs uplink power control by changing a preset PO2 value to the PO2 value.

The system configured as described above may increase the success rate of uplink power control in a mixed radio region having a plurality of radio links by setting different PO2 values of the downlink power control frame for uplink power control according to the number of radio links. This can improve uplink voice and data quality.

4 is a block diagram schematically showing the configuration of a base station controller according to the present invention.

Referring to FIG. 4, the base station controller 300 includes a communication interface unit 302 for communication with a user terminal or a base station, a base station information database 304 storing a number of radio links for each base station, a handover control unit 306, and a PO2 value. The decision unit 308 is included.

When the measurement report message is received from the user terminal through the communication interface unit 302, the handover control unit 306 determines whether a handover is required, and when the handover is necessary, through the communication interface unit 302. The base station requests a radio link setting and receives a response.

That is, the handover control unit 306 determines that the handover should be performed when the signal strength in the measurement report message is greater than a specified value, and requests the target base station to establish a new radio link.

In addition, the handover controller 306 analyzes the measurement report message and determines that handover should be performed when the measurement quality of the target base station is better than that of the source base station. Request setup.

The handover control unit 306 determines whether to handover according to an event in the measurement report message.

Then, the target base station establishes a radio link according to the radio link establishment request, and transmits a radio link establishment response.

When the radio link is established as described above, the handover control unit 306 sets up a signaling radio bearer (SRB) for signaling in an Iub section indicating an interface between the base station controller 300 and the base station and traffic radio for the traffic. Bearer) setup process is performed.

In addition, the handover control unit 306 notifies that the setting of a new radio link is completed to the user terminal through the communication interface unit 302 when resource allocation for handover is completed in the target base station.

The PO2 value determination unit 308 checks the number of radio links set in the target base station from the base station information database 304, determines the PO2 value based on the identified number of radio links, and changes the PO2 value to the target base station. Send the request signal.

At this time, the PO2 value determination unit 308 determines the PO2 value differently according to the case where the number of radio links is two and the number of three or more radio links. That is, the PO2 value can be transmitted using a 5-bit field and can be transmitted from 0 to 31, and the step size is 0.25 dB. Therefore, the PO2 value can be set from 0dB to 7.75dB, and has a different value depending on the number of two radio links and the case of three or more, which can be changed by an operator.

For example, the PO2 value determination unit 308 sets the PO2 value to 3 dB when the number of radio links is 2, and sets the PO2 value to 6 dB when the number of radio links is 3 or more. At this time, 3 dB is obtained by (12 X 0.25 dB = 3 dB), and 6 dB is obtained by (24 X 0.25 dB = 6 dB).

Accordingly, the PO2 value determiner 308 transmits 12 to the base station when the number of radio links is two, and transmits 24 to the base station when the number of radio links is three or more.

Then, the base station sets the PO2 value to 3dB when 12 is received as the PO2 value, and sets the PO2 value to 6dB when 24 is received as the PO2 value.

5 is a block diagram schematically showing the configuration of a base station according to the present invention.

Referring to FIG. 5, the base station 200 includes a communication interface unit 202, a storage unit 204, a radio link setting unit 206, and a PO2 value setting unit 208 for communication with a user terminal or a base station controller. Include.

When the radio link setting is requested from the base station controller through the communication interface unit 202, the radio link setting unit 206 establishes a radio link and transmits the response to the base station controller.

That is, when the radio link setting request is made from the base station controller, the radio link setting unit 206 establishes a radio link and transmits a radio link setting response to the base station controller.

When the PO2 value change request signal including the PO2 value is received from the base station controller through the communication interface unit 202, the PO2 value setting unit 208 converts the PO2 value into downlink power for uplink power control. Set to the PO2 value of the control frame.

In addition, the PO2 value setting unit 208 generates a transmission power command (TPC) message including the set PO2 value and transmits it to the user terminal.

6 illustrates an uplink power control method according to the present invention.

Referring to FIG. 6, when a measurement report message is received from the user terminal (S800), the base station controller determines whether to perform a handover using the measurement report message (S802). That is, the base station controller determines that handover should be performed when the signal strength in the measurement report message is greater than a specified value.

If it is determined in step S802 that a handover is necessary, the base station controller requests a target radio to establish a new radio link (S804).

Then, the target base station establishes a radio link according to the radio link establishment request, and transmits a radio link establishment response to the base station controller (S806).

At this time, the base station controller and the target base station performs a signaling radio bearer (SRB) configuration for signaling in the Iub interval and a traffic radio bearer (TRB) configuration for traffic.

When S806 is performed, the base station controller determines a PO2 value based on the number of radio links set in the target base station (S808), and transmits a PO2 value change request signal including the determined PO2 value to the target base station (S808). S810).

Then, the target base station sets the PO2 value included in the PO2 value change request signal to the PO2 value of the downlink power control frame for uplink power control (S812). At this time, the target base station generates a transmit power command (TPC) message including the set PO2 value and transmits it to the user terminal. Then, the user terminal performs uplink power control by changing a preset PO2 value to the PO2 value.

When the S812 is performed, the base station controller transmits an Active Set Update message indicating that the establishment of a new radio link is completed to the user terminal (S814).

Then, the user terminal completes resource allocation and radio link setting for a new signal and transmits an Active Set Update Complete message to the base station controller (S816).

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

As described above, the uplink power control system and method of the present invention sets up a power offset value of a downlink power control frame for uplink power control according to the number of radio links, thereby uplinking in a mixed radio region having a plurality of radio links. It is suitable for increasing power control success rate and improving uplink voice and data quality.

100: user terminal 200: base station
202, 302: communication interface unit 204: storage unit
206: wireless link setting unit 208: PO2 value setting unit
300: base station controller 304: base station information database
306: handover control unit 308: PO2 value determination unit

Claims (10)

When the measurement report message is received from the user terminal, it is determined whether a handover is required, and when a handover is required, a request is made to set up a radio link to a target base station to receive a response, and based on the number of radio links set in the target base station, PO2 is determined. A base station controller for determining a value of (PowerOffset2) and transmitting a PO2 value change request signal to the target base station; And
In response to a radio link setting request from the base station controller, a radio link is established and a response is transmitted to the base station controller, and the PO2 value included in the PO2 value change request signal is transmitted in a downlink power control frame for uplink power control. A target base station set to a PO2 value;
Uplink power control system comprising a. The method of claim 1,
The base station generates a transmission power command (TPC) message including the set PO2 value and transmits it to the user terminal,
The user terminal performs uplink power control by changing a preset PO2 value to the PO2 value. A communication interface unit for communication with a user terminal or a base station;
A base station information database storing the number of radio links for each base station;
When a measurement report message is received from the user terminal through the communication interface unit, it is determined whether a handover is required, and when handover is required, a handover requesting a radio link setting to a target base station through the communication interface unit and receiving the response Control unit; And
A PO2 value determination unit which checks the number of radio links set in the target base station from the base station information database, determines a PO2 value based on the identified number of radio links, and transmits a PO2 value change request signal to the target base station;
Base station controller comprising a. The method of claim 3,
The PO2 value determining unit determines the PO2 value differently by dividing into two or three or more radio links. A communication interface unit for communicating with a user terminal or a base station controller;
A radio link setting unit for setting a radio link and transmitting a response to the base station controller when a radio link setting is requested from the base station controller through the communication interface unit; And
A PO2 value setting unit configured to set the PO2 value to a PO2 value of a downlink power control frame for uplink power control when a PO2 value change request signal including a PO2 value is received from the base station controller through the communication interface unit;
/ RTI > The method of claim 5,
The PO2 value setting unit generates a transmission power command (TPC) message including the set PO2 value and transmits to the user terminal. When the base station controller receives the measurement report message from the user terminal, determining whether to perform a handover, and requesting a radio link setup from the target base station when the handover is necessary;
Setting, by the target base station, a radio link according to the radio link establishment request and transmitting a response to the base station controller;
Determining, by the base station controller, a PO2 value based on the number of radio links set in the target base station, and transmitting a PO2 value change request signal including the determined PO2 value to the target base station;
The target base station sets the PO2 value included in the PO2 value change request signal to a PO2 value of a downlink power control frame for uplink power control, and generates a transmit power command (TPC) message including the set PO2 value. Transmitting to the user terminal; And
Changing, by the user terminal, a preset PO2 value to a PO2 value in the transmission power command (TPC) message and completing a radio link setting;
Uplink power control method comprising a. In the method for the base station controller to control the uplink power,
When the measurement report message is received from the user terminal, determining whether to handover;
Requesting a radio link establishment from a target base station and receiving a response if a handover is necessary as a result of the determination;
Checking the number of radio links set in the target base station and determining a PO2 value based on the identified number of radio links; And
Transmitting a PO2 value change request signal including the determined PO2 value to the target base station and notifying the user terminal of completion of radio link setting;
Uplink power control method comprising a. In the method for the base station to control the uplink power,
(a) when the PO2 value change request signal including the PO2 value is received from the base station controller, setting the PO2 value to a PO2 value of a downlink power control frame for uplink power control; And
(b) generating and transmitting a transmit power command (TPC) message including the set PO2 value to a user terminal;
Uplink power control method comprising a. 10. The method of claim 9,
And setting up a radio link and transmitting a response to the base station controller when the radio link setting is requested from the base station controller.

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