KR101794724B1 - System and Method for controlling Uplink power - Google Patents

Abstract

The present invention relates to an uplink power control system and method, and more particularly, to a system and method for an uplink power control that determines whether a handover is performed when a measurement report message is received from a user terminal, 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, a radio link setting unit for setting a radio link according to a radio link setting request from the base station controller, Response to the base station controller, and sets a PO2 value included in the PO2 value change request signal as a PO2 value of a downlink power control frame for uplink power control.
Therefore, 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 uplink power control success rate can be increased in the radio wave mixed region having a plurality of radio links , Thereby improving the uplink voice and data quality.

Description

Technical Field [0001] The present invention relates to an uplink power control system,

The present invention relates to an uplink power control system and method, and more particularly, to a system and method for controlling uplink power, and more particularly, (PowerOffset2) value based on the number of radio links set in the target base station and transmits a PO2 value change request signal to the target base station, the target base station transmits the PO2 value change request signal To a PO2 value of a downlink power control frame (TPC frame) for uplink power control.

The wireless communication system uses a power control scheme as a method for reducing inter-cell interference due to path loss and interference from adjacent cells depending on the distance between the base station and the terminal.

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

FIG. 1 illustrates a conventional uplink power control method, and FIG. 2 illustrates a general downlink power control frame structure. Referring to FIG.

1, in the uplink power control, the SINR value measured at the base station measuring the signal to interference / noise ratio (SINR) (or Eb / No) value of the uplink dedicated physical control channel (DPCCH) If the target SINR value is higher than the target SINR value, a command is issued to lower the output of the user terminal using the transmission power command (TPC) of the downlink DPCCH. At this time, the control on the output of the user terminal means control of the uplink DPCCH power, and the power of the DPCCH moves in conjunction with the DPCCH according to the designated ratio.

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

The uplink inner loop power control controls the level of the uplink DPCCH while the downlink inner loop power control controls the level of the downlink DPDCH (Dedicated Physical Data Channel).

The power ratio of the downlink DPCCH to the DPDCH of the TPC (TPCI), the pilot symbol, and the DPDCH of the downlink DPCCH are defined by the operator and defined by the parameters PO1 (Power Offset 1), PO2 and PO3, respectively.

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

The transmission power value of the power control frame is determined by an offset (Power Offset 2, hereinafter referred to as PO2) of the downlink DPDCH power, which can range from a minimum of 0 dB to a maximum of 7.75 dB.

However, conventionally, since the PO2 value determined by the operator is statically used, if the PO2 value is set low, the success rate of the uplink inner loop power control becomes low, and if the PO2 value is set high, the peripheral user interference becomes large.

Also, in a radio wave mixed area (for example, in a building) having a plurality of wireless links, a transmission failure of a power control frame occurs, an uplink power control execution error occurs, and uplink voice and data quality deteriorate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to improve uplink power control success rate in a radio mixed area (for example, in a building) And to provide an uplink power control system and method that can improve the uplink power control.

According to an aspect of the present invention, there is provided a method for determining whether a handover is performed when a measurement report message is received from a user terminal, requesting a target base station to establish a radio link when handover is required, 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, a radio link setting unit for setting a radio link according to a radio link setting request from the base station controller, And a target BS for setting a PO2 value included in the PO2 value change request signal as 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 transmission power command (TPC) message including the set PO2 value and transmits it to the user terminal. The user terminal changes the predetermined PO2 value to the PO2 value to perform uplink power control.

According to another aspect of the present invention, there is provided a mobile communication system including a communication interface for communication with a user terminal or a base station, a base station information database in which the number of radio links per base station is stored, A handover controller for requesting establishment of a radio link to the target base station through the communication interface unit when a handover is required and receiving a response thereto; checking the number of radio links established in the target base station from the base station information database, And a PO2 value determining unit for determining a value of PO2 based on the number of confirmed radio links and transmitting a PO2 value change request signal to the target base station.

The PO2 value determination unit determines PO2 values differently when the number of wireless links is two or when the number of wireless links is three or more.

According to another aspect of the present invention, there is provided a communication system including a communication interface unit for communication with a user terminal or a base station controller, and a base station controller configured to establish a radio link when a radio link setup is requested from the base station controller through the communication interface, When a PO2 value change request signal including a PO2 value is received from the base station controller through the communication interface unit, the PO2 value is transmitted to a PO2 of a downlink power control frame for uplink power control And a PO2 value setting section for setting the PO2 value to a value.

The PO2 value setting unit generates a transmission power command (TPC) message including the set PO2 value and transmits the message to the user terminal.

According to another aspect of the present invention, there is provided a method for controlling a target base station, the method comprising the steps of: determining whether a handover is performed when a base station controller receives a measurement report message from a user terminal; Setting a radio link according to the radio link setup request and transmitting the response to the base station controller; determining a PO2 value based on the number of radio links set in the target base station; Transmitting a PO2 value change request signal to the target BS by the target base station, the PO2 value included in the PO2 value change request signal being a PO2 value of a downlink power control frame for uplink power control Generates a transmission power command (TPC) message including the set PO2 value, and transmits it to the user terminal And transmitting the uplink power control signal.

According to another aspect of the present invention, there is provided a method for controlling uplink power of a base station controller, comprising: determining whether a handover is performed when a measurement report message is received from a user terminal; Determining a number of radio links set in the target base station and determining a value of PO2 on the basis of the number of radio links determined; And transmitting the PO2 value change request signal to the target base station and informing the user terminal of completion of the wireless link setup.

According to another aspect of the present invention, there is provided a method for controlling uplink power of a base station, the method comprising the steps of: (a) receiving a PO2 value change request signal including a PO2 value from a base station controller, (B) generating a transmit power command (TPC) message including the set PO2 value and transmitting the generated transmit power command (TPC) message to a user terminal / RTI >

The uplink power control method may further comprise setting a radio link and transmitting a response to the base station controller when a radio link setup 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 uplink power control success rate in a mixed radio- , Thereby improving the uplink voice and data quality.

In addition, performance can be improved by minimizing peripheral user interference in a radio wave mixed area having a plurality of radio links.

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

Hereinafter, the base station will be referred to as a base station (BS) in the second generation mobile communication and the Node-B in the third generation mobile communication, and will be collectively referred to as a base station in the following description.

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

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

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

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 is increased due to a handover of a user terminal 100, And a base station 200a or 200b for setting a PO2 value from the base station 300 as a PO2 value of a 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 performs handover from the first base station 200a to the second base station 200b according to the measurement report message.

Handover refers to a process of automatically tuning to a new communication channel of an adjacent communication service area when the user terminal 100 moves out of the current communication service area and moves to an adjacent communication service area to continuously maintain the communication state Function. That is, the user terminal 100 communicating with a particular base station is linked to a neighboring base station when signal strength at the particular base station is weak.

Handover is determined 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, an event refers to a condition or an event to occur in order to perform handover, and a measurement report message refers to a message reporting measurement information related to an event to an access point when an event occurs.

In order to transmit the measurement report message for the base station change, there are two conditions. First, the measurement information of the target base station is better than the measurement information of the source base station. Second, the first condition is a time to trigger time. TTT).

The user terminal 100 reports a 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 transmitted from the user terminal 100 to the base station as an event occurs.

Referring to Table 1, the measurement report message related to the event occurrence is a message for changing the base station reporting when the user terminal 100 moves from the source base station to the target base station.

The measurement report message related to the event occurrence is as follows. The conditions for generating the measurement report message related to the event 1D are as follows.

First, the measurement quality measured at the target base station in the vicinity of the source base station must be satisfied with the measurement quality being better than the measurement quality of the source base station. Secondly, this condition must be satisfied continuously for a constant driving time.

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

The measurement report message relating to the occurrence of the event 1F is a message for adding the information of the neighboring base station to the radio link when the signal strength at the neighboring base station adjacent to the source base station is larger than the threshold value. The condition for generating the measurement report message relating to event 1F (i.e., the condition for generating event 1F) is as follows. First, the measurement quality measured at the neighboring base stations around the source base station must be satisfied above a certain threshold, and secondly, 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 and detects the occurrence of the event described in Table 1. [ The measurement information refers to any measurable information that helps the user terminal 100 to recognize the presence of the base station, such as the signal strength or signal strength transmitted from the base station. As the measurement information, the power of the reference signal, the quality of the reference signal, the block error rate of the downlink physical channel, and the like can be used.

When an event is detected, the user terminal 100 generates a measurement report message and transmits a measurement report message to the source base station. As described above, the measurement report message includes various information necessary for the mobility management procedure of the user terminal 100 as described above, and may include measurement information of the source base station and the target base station as well as the detection result of the event. The base station controller 300, which is in charge of the source base station, can perform the handover upon receiving the measurement report message.

If the measurement report message is received from the user terminal 100, the base station controller 300 determines whether the handover is required. If the handover is required, the base station controller 300 requests the second base station 200b to establish a radio link, Determines a 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 relative to the DPDCH. PO (PowerOffset) is a constant defined according to frequency and radio configuration, and refers to up / down path attenuation compensation value according to frequency and spreading factor.

The base station controller 300 determines whether a handover is performed according to an event in the measurement report message. For example, when a measurement report message regarding the event 1E is received, the base station controller 300 determines that handover should be performed if the signal strength in the measurement report message is greater than a specified value, (210b) to request the establishment of a new radio link.

In addition, when the measurement report message related to the event 1D is received, the base station controller 300 analyzes the measurement report message, and if the measurement quality of the target base station is better than the measurement quality of the source base station, And requests the second base station 210b, which is the target base station, to establish a new radio link.

The second base station 200b establishes a radio link according to a radio link setup request from the base station controller 300 and transmits the response to the base station controller 300. The second base station 200b transmits a PO2 Value as 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 the message to the user terminal 100. [

Then, the user terminal 100 changes the predetermined PO2 value to the PO2 value to perform uplink power control.

In the system configured as described above, the PO2 value of the downlink power control frame for uplink power control may be set differently according to the number of radio links, thereby increasing the uplink power control success rate in the radio wave mixed region having a plurality of radio links, Thereby improving uplink voice and data quality.

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

4, the base station controller 300 includes a communication interface 302 for communication with a user terminal or a base station, a base station information database 304 in which the number of radio links per base station is stored, a handover controller 306, And a determination unit 308.

When the measurement report message is received from the user terminal through the communication interface 302, the handover controller 306 determines whether or not the handover is performed. If handover is required, the handover controller 306 transmits the measurement report message through the communication interface 302 Requests the base station to establish a radio link, and receives the response.

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

In addition, when the measurement quality of the target BS becomes better than the measurement quality of the source BS by analyzing the measurement report message, the handover controller 306 determines that the handover should be performed, Request configuration.

The handover control unit 306 determines whether or not the handover is performed according to an event in the measurement report message.

Then, the target BS establishes a radio link according to the radio link setup request, and transmits a radio link setup response.

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

The handover controller 306 informs the user terminal of the completion of the establishment of a new radio link through the communication interface 302 when the resource allocation for the handover is completed in the target base station.

The PO2 value determination unit 308 determines the number of radio links set in the target base station from the base station information database 304 and determines the value of PO2 based on the number of the confirmed radio links, Request signal.

At this time, the PO2 value determination unit 308 determines PO2 values differently depending on whether the number of wireless links is two or more than three. That is, the PO2 value can be transmitted using the 5-bit field and can be transmitted from 0 to 31, and the step size is 0.25 dB. Accordingly, the PO2 value can be set from 0dB to 7.75dB, and the number of wireless links has a different value depending on whether the number of wireless links is two or 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 wireless links is two and the PO2 value to 6 dB when the number of wireless links is three 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).

Therefore, the PO2 value determining unit 308 transmits 12 to the base station as PO2 value when the number of wireless links is two, and transmits 24 as PO2 value to the base station when the number of wireless links is three or more.

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

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

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

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

That is, when the wireless link setting unit 206 requests the wireless link setting unit 206, the wireless link setting unit 206 sets a wireless link and transmits a wireless 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 sets the PO2 value to the downlink power for uplink power control Set as PO2 value of control frame.

Also, 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 is a diagram illustrating an uplink power control method according to the present invention.

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

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

In step S806, the target BS establishes a radio link according to the radio link setup request and transmits a radio link setup response to the base station controller.

At this time, the base station controller and the target base station perform an SRB (Signaling Radio Bearer) setup for signaling of the Iub interval and a TRB (Traffic Radio Bearer) setup process for traffic.

When the step 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 S810).

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

If the step S812 is performed, the base station controller transmits an Active Set Update message informing that the setting of a new wireless link is completed to the user terminal (S814).

Then, the user terminal completes the resource allocation and the radio link setup for the 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, according to the uplink power control system and method of the present invention, the power offset value of the downlink power control frame for uplink power control is set differently according to the number of radio links, It is suitable for increasing the power control success rate and improving the uplink voice and data quality.

100: user terminal 200: base station
202, 302: Communication interface unit 204:
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)

delete delete A communication interface for communicating with a user terminal or a base station;
A base station information database in which the number of radio links per base station is stored;
And a handover control unit configured to determine whether a handover is to be performed when the measurement report message is received from the user terminal through the communication interface unit, to request a target base station to establish a radio link through the communication interface unit, A control unit; And
Determines a PO2 value based on the number of radio links that have been changed due to the handover of the user terminal based on the base station information database and changes the PO2 value to the target base station, A PO2 value determination unit for transmitting the PO2 value;
/ RTI > The method of claim 3,
Wherein the PO2 value determining unit determines PO2 values differently when the number of wireless links is two or when the number of wireless links is three or more. In the base station,
A communication interface unit for communication with the base station controller;
A radio link setting unit for setting a radio link according to a request and transmitting a response to the base station controller when a radio link setting is requested from the base station controller to a user terminal handed over from the other base station to the base station; And
When the PO2 value change request signal including the PO2 value determined based on the number of radio links of the base station changed due to the handover of the user terminal from the base station controller is received, the PO2 value is transmitted as a downlink A PO2 value setting unit for setting the PO2 value of the power control frame;
/ RTI > 6. The method of claim 5,
Wherein the PO2 value setting unit generates a transmission power command (TPC) message including the set PO2 value and transmits the message to the user terminal. delete A method for a base station controller to control uplink power,
Determining whether a handover is performed when a measurement report message is received from a user terminal;
Requesting establishment of a radio link to a target base station and receiving a response if the handover is required;
Confirming the number of radio links of the target base station changed due to the handover of the user terminal and determining the value of PO2 based on the number of radio links identified; And
Transmitting a PO2 value change request signal including the determined PO2 value to the target BS, and informing the user terminal of completion of the wireless link setup;
/ RTI > A method for a base station to control uplink power,
Setting a radio link according to a request and transmitting a response to the base station controller when a radio link setup is requested from a base station controller to a user terminal handed over from another base station to the base station;
When the PO2 value change request signal including the PO2 value determined based on the number of radio links of the base station changed due to the handover of the user terminal from the base station controller is received, the PO2 value is transmitted as a downlink Setting a PO2 value of a power control frame; And
Generating a transmit power command (TPC) message including the set PO2 value and transmitting the message to a user terminal;
/ RTI >
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