KR100933150B1 - Power control method using mobile information of portable terminal - Google Patents

Abstract

The present invention provides a power control method using mobile information of a portable terminal capable of performing efficient power control in consideration of the mobile situation of the portable terminal. First, the reception quality of the received data is measured, and a target SIR is set based on the measured reception quality. Then, the power is controlled using the corrected target SIR after correcting the set target SIR based on the movement information of the portable terminal. Accordingly, power control may be performed by predicting fading according to a moving speed and a location of the portable terminal, and thus, by performing optimal power control, it may always satisfy a certain quality of service.

Handheld Terminals, Power Control, GPS, BLER, SIR

Description

Method for Controlling of Transmition Power Using Mobility Information Of Portable Terminal}

The present invention relates to power control of a mobile communication system, and more particularly, to a power control method using mobile information of a portable terminal capable of performing efficient power control in consideration of the mobile situation of the portable terminal.

Wideband Code Division Mutilple Access (WCDMA) is the third generation of wireless access technology introduced for multimedia services that require high channel capacity, enabling the delivery of high-quality images and video for communication between individuals and the rapid transfer of data. Speed enables information access and services on public and private networks.

In the mobile communication system using the radio access technology as described above, since the distance between the base station and the mobile station (ie, the portable terminal) may vary, the uplink signals transmitted from different portable terminals to the base station may have different power levels. Can be.

For example, a signal transmitted from a portable terminal located close to the base station may have a high power level, and a signal transmitted from a portable terminal located far from the base station may have a relatively low power level. Will cause interference with low power signals, which will result in a near-far problem where weak power signals cannot communicate normally.

In the mobile communication system, power control is performed to maintain the interference between the portable terminals generated in the air interface at the lowest level and to satisfy the required quality of service (QoS).

Power control includes inner closed loop power control and outer loop power control.

Internal closed-loop power control evaluates the signal-to-interference ratio (SIR) for a certain period at a base station at regular intervals and compares the evaluated SIR with a reference SIR. Accordingly, a method of controlling a portable terminal to increase or decrease transmission power, and the outer loop power control controls a target SIR of a base station according to individual radio access needs and maintains a quality of service.

The control period of the inner closed loop power control is 1.5 kHz, and the control period of the outer loop power control is 10 to 100 Hz.

1 is a flowchart illustrating a power control method of a general mobile communication system.

Referring to FIG. 1, a base station first receives data transmitted through a dedicated channel (DCH: Dedicated Channel) from a mobile terminal (step 11), decodes the received data, and then receives a block error rate of data received through a CRC ( BLER: Block Error Ratio, hereinafter abbreviated as 'BLER') is calculated (step 13).

Then, the base station compares the calculated BLER with a preset reference BLER (step 15), and if the calculated BLER is larger than the reference BLER, increases the target SIR by a predetermined step to change the target SIR (step 17), and calculates the calculated BLER. If the BLER is smaller than the reference BLER, the target SIR is decreased by a predetermined step to change the target SIR (step 19).

Then, power control is performed based on the target SIR increased or decreased in step 17 or step 19 (step 21).

The conventional power control method as shown in FIG. 1 does not take into account the moving speed of the portable terminal, the moving direction, the topographic information of the current location, and the topographic information of the moving direction of the portable terminal, and depends only on the BLER of the received data. Since power control is performed, power control based on the mobility of the portable terminal is not performed, and thus, there is a disadvantage in that the required quality of service cannot be kept constant.

For example, in the conventional power control method, since the portable terminal performs power control depending on the BLER of the received data even when the portable terminal moves at a high speed (over 100 km / h) from a flat area to a heavily fading area, power control is performed. Even at this moment, the portable terminal is moved, and as a result, efficient power control is not achieved, thereby failing to satisfy a required quality of service.

Accordingly, an object of the present invention is to provide a power control method using mobile information of a portable terminal capable of performing efficient power control in consideration of the mobile situation of the portable terminal.

Another object of the present invention is to provide a power control method using mobile information of a portable terminal capable of providing excellent service quality.

According to an aspect of the present invention, there is provided a power control method using mobile information of a portable terminal, the method comprising: measuring a reception quality of received data and based on the measured reception quality; And setting a target signal to interference ratio (SIR) and correcting the set target SIR based on movement information of the portable terminal. The correcting of the set target SIR based on the location information of the portable terminal may include receiving location information of the portable terminal and obtaining movement information of the portable terminal from the received location information of the portable terminal. And acquiring a power control factor based on the obtained mobile terminal movement information and correcting the set target SIR based on the obtained power control factor. The movement information of the portable terminal may include at least one of a moving speed of the portable terminal, a moving direction, and a terrain complexity of a place where the portable terminal is located. Acquiring a power control factor based on the obtained mobile terminal movement information may include acquiring a first power control factor corresponding to a moving speed of the portable terminal and a terrain complexity of a place where the portable terminal is located. Obtaining a corresponding second power control factor. The acquiring of the first power control factor corresponding to the moving speed of the portable terminal may include an increasing step size corresponding to the current moving speed of the portable terminal among the increasing step sizes of the target SIR set for each moving speed of the portable terminal. Can be obtained. The acquiring of the second power control factor corresponding to the terrain complexity of the place where the portable terminal is located may be performed by dividing the terrain complexity of the region where the portable terminal is located into a predetermined number of levels based on a predetermined criterion. An increase step size corresponding to a local complexity level of a place where the portable terminal is located among the increase step sizes of the target SIR set for each complexity level may be obtained. Measuring the reception quality of the received data may measure the BLER of the received data. The step of setting a target SIR based on the measured reception quality compares the measured BLER with a preset reference BLER and increases the target SIR if the measured BLER is larger than a preset reference BLER, and the measured BLER If it is smaller than this predetermined reference BLER, the target SIR can be reduced.

According to the power control method using the mobile information of the portable terminal as described above, the BLER of the received data is measured and the target SIR is set according to the measurement result. In addition, the first control factor is obtained based on the moving speed of the portable terminal, and the first control factor and the second control factor obtained after the second control factor are acquired according to the moving direction and the terrain complexity of the portable terminal. Correct the set target SIR.

Therefore, power control is performed considering not only the BLER of the received data but also the moving speed of the portable terminal, the direction of travel, and the topographic information of the location where the portable terminal is located, thereby predicting fading according to the moving speed and position of the portable terminal. It is possible to satisfy the constant quality of service by performing optimal power control.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

2 is a flowchart illustrating a power control process using mobile information of a portable terminal according to an embodiment of the present invention, and FIG. 3 illustrates a first control factor according to an embodiment of the present invention. 4 illustrates a second control factor according to an embodiment of the present invention.

2 to 4, first, a base station (eg, Node-B, or base station) receives data transmitted from a portable terminal (ie, user equipment) through an uplink channel (step 101), and receives the data. After the decoded data is decoded, a block error ratio (BLER: abbreviated as 'BLER') of the received data is measured through error checking (step 103).

In this case, the data may be transmitted through a dedicated data channel (DCH: hereinafter, abbreviated as 'DCH'). The DCH is a type of transport channel that transmits not only the actual service but also all information for the user including the higher layer information signal. In addition, the error check may be performed through a cyclic redundancy check (CRC).

Then, the base station provides the measured BLER information to a radio network controller (RNC), and the radio network controller compares the measured BLER provided from the base station with a preset reference BLER (step 105), and the calculated BLER is If larger than the reference BLER, that is, if it is determined that the transmission quality is low, the target SIR is increased to the base station (step 107).

Or, the wireless network controller reduces the target SIR if the measured BLER is smaller than the reference BLER, that is, if the transmission quality is better than the reference (step 109).

In steps 107 and 109, the target SIR may be increased or decreased in units of 0.5 dB.

Then, the base station receives the location information (for example, GPS pseudo range) transmitted from the portable terminal, and transmits the received location information to the radio network controller (step 111).

Here, the terminal may receive a location measurement control message through a system information or a measurement control message broadcast from a base station or a wireless network controller, and the location measured through a measurement report message Information can be sent to the base station.

In addition, the portable terminal may include a GPS receiver to transmit its location information to the base station, and the location information may include a moving speed of the portable terminal and / or coordinates of the current location.

The wireless network controller acquires the movement information of the portable terminal such as the moving speed of the portable terminal, the direction of movement, and the topographical complexity of the location where the portable terminal is currently located, based on the position information of the portable terminal transmitted from the base station. A first control factor and a second control factor are obtained based on the information (step 113).

As shown in FIG. 3, the first control factor is an increase step size of the reference SIR corresponding to the moving speed of the portable terminal, and the increase step size for each moving speed may be set by repeated experiments. In FIG. 3, for example, the step size for each moving speed is increased. For example, the step size for each moving speed may be set to decrease as well as increase.

As shown in FIG. 4, the second control factor represents an increase step size of the reference SIR corresponding to the topography complexity of the current location of the portable terminal and the moving direction of the portable terminal.

For example, based on a predetermined criterion such as visibility, building height, building density, etc., the terrain complexity is divided into a predetermined number of levels, and the higher the terrain complexity, the larger the step step size of the reference SIR is set, and the lower the terrain complexity is. The increase step size of the reference SIR is set small. In addition, the step size is increased or decreased according to the current movement direction of the portable terminal.

For example, as shown in FIG. 4, the terrain complexity is divided into six levels from 1 level (lowest) to 6 levels (highest), and the step size is increased by a predetermined size as the terrain complexity increases. . In addition, when the portable terminal moves in a direction with high terrain complexity, the step size is set to increase by a predetermined size. When the portable terminal moves in a direction where the terrain complexity level is low, the step size is decreased by a predetermined size. .

When the first control factor and the second control factor are acquired in step 113, the radio network controller corrects the changed target SIR in step 107 or 109 in consideration of the obtained first control factor and the second control factor (step 115).

Thereafter, the radio network controller transmits the corrected target SIR to the base station.

The base station performs power control (eg, fast closed loop power control) based on the corrected target SIR transmitted from the radio network controller.

Since fast closed-loop power control corresponds to a known technique, it is not shown in detail, but the base station measures the SIR received from the portable terminal, compares it with the corrected target SIR, and if the measured SIR is higher than the corrected target SIR, Sends a control message to the portable terminal instructing to decrease the transmission power by a predetermined step size, and if the measured SIR is lower than the corrected target SIR, sends a control message instructing to increase the transmission power by a predetermined predetermined step size. Transfer to a portable terminal.

In this case, the control on the increase or decrease of the transmission power may be performed by including a transmission power control (TPC) bit in the downlink transmission channel, that is, the DCH.

In the power control process illustrated in FIG. 2, steps 101 to 109 and steps 111 to 113 may be reversed. That is, the first control factor and the second control factor are first measured based on the location information of the portable terminal (steps 111 to 113), and then the target SIR is changed based on the BLER of the received data (steps 101 to 109). ) You may.

In addition, as shown in Figures 2 to 4 in the power control method using the movement information of the portable terminal according to an embodiment of the present invention, the power control is performed in consideration of the moving speed, the moving direction and the complexity of the terrain of the portable terminal. In order to do so, the base station and / or the radio network controller may use a geographic information system (GIS).

For example, the wireless network controller may obtain terrain information corresponding to the current location of the portable terminal from the geographic information system to determine the terrain complexity, and determine the terrain complexity based on the acquired terrain information.

In addition, the wireless network controller may track the moving path and the moving direction of the portable terminal by interworking the location information transmitted from the portable terminal and the geographic information system, and acquire a second control factor accordingly.

As an example of power control with reference to FIGS. 2-4, if the current target SIR is 10 dB and the measured BLER is greater than the reference BLER, the wireless network controller increases the target SIR by a predetermined step size (eg, 0.5 dB). In addition, assuming that the current mobile terminal has a movement speed of 75 km / h, a terrain complexity of two levels, and a moving direction of the portable terminal in a direction of increasing terrain complexity level, the first control factor is +0.1 dB, and the second control factor. Becomes +0.3 dB. Thus, the corrected target SIR is 10.9 dB, and the increase step size of the target SIR is 0.9 dB.

As shown in FIG. 2, in the power control method of a portable terminal according to an embodiment of the present invention, the power control is performed in consideration of the moving speed, the moving direction, and the topographic information of the location where the portable terminal is located, as well as the BLER. Therefore, power control may be performed by predicting fading according to a moving speed and a location of the portable terminal, and thus, by performing optimal power control, it may always satisfy a certain quality of service.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

1 is a flowchart illustrating a power control method of a general mobile communication system.

2 is a flowchart illustrating a power control process using movement information of a portable terminal according to an embodiment of the present invention.

3 shows a first control factor according to an embodiment of the invention.

4 shows a second control factor according to an embodiment of the invention.

Claims (8)

In the power control method of a portable terminal, Measuring a reception quality of the received data; Setting a target signal to interference ratio (SIR) based on the measured reception quality; Receiving location information of the portable terminal; Obtaining movement information of the portable terminal from the received position information of the portable terminal; Obtaining a power control factor of at least one of a first power control factor corresponding to a moving speed of the portable terminal and a second power control factor corresponding to a terrain complexity of a location where the portable terminal is located from the mobile information of the portable terminal; ; And And correcting the set target SIR based on the obtained at least one power control factor. delete The method of claim 1, wherein the movement information of the portable terminal, And at least one of a moving speed of the portable terminal, a moving direction, and a topographical complexity of a location where the portable terminal is located. delete The method of claim 1, wherein the power of at least one of the first power control factor corresponding to the moving speed of the portable terminal from the movement information of the portable terminal and the second power control factor corresponding to the topography complexity of the location where the portable terminal is located; Acquiring the control factor, Obtaining the increase step size corresponding to the current movement speed of the portable terminal among the increase step sizes of the target SIR set for each movement speed of the portable terminal as the first power control factor. Power control method used. The method of claim 1, wherein the power of at least one of the first power control factor corresponding to the moving speed of the portable terminal from the movement information of the portable terminal and the second power control factor corresponding to the topography complexity of the location where the portable terminal is located; Acquiring the control factor, The geographic complexity of the area where the portable terminal is located is divided into a predetermined number of levels based on a predetermined criterion, and the area complexity level of the place where the portable terminal is located among the increase step sizes of the target SIR set for each of the divided geographic complexity levels. And obtaining the increase step size corresponding to the second power control factor according to the movement information of the portable terminal. The method of claim 1, wherein measuring the reception quality of the received data comprises: A power control method using movement information of a portable terminal, characterized in that for measuring the BLER of the received data. The method of claim 7, wherein setting a target SIR based on the measured reception quality, Compare the measured BLER and a predetermined reference BLER and increase the target SIR if the measured BLER is larger than the predetermined reference BLER, and decrease the target SIR if the measured BLER is smaller than the predetermined reference BLER. Power control method using the movement information of the portable terminal, characterized in that.

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