KR100662368B1 - An outer loop power control method for a wireless communication system - Google Patents

Abstract

In the method of controlling an external loop power of a wireless communication system in which data is transmitted to a block through a communication channel and channel transmission control is performed using received block error rate information of the data block, the energy measurement result of a dedicated physical control channel (DPCCH) Determining whether to perform the operation of the outer loop power control according to the outer loop power control method of the wireless communication system.

OLPC. dpcch, tentative delta value

Description

An outer loop power control method for a wireless communication system

1 is an exemplary view showing a configuration of an external loop power control apparatus of a mobile communication system according to the prior art.

2 is a flow chart showing the progress of the outer loop power control method according to the present invention.

The present invention relates to a method for controlling the outer loop power of a wireless communication system, and more particularly, to a method for appropriately responding to sudden channel deterioration by determining whether to operate the outer loop power control according to a change in the channel environment. will be.

In the mobile communication system, a plurality of subscribing terminals divided by code share the same frequency channel at the same time, and the output power level of each other must be kept the same between adjacent terminals, and the output power of a specific terminal is high. In this case, the interference is recognized by the adjacent terminal as noise, and the output is increased to increase the signal-to-noise ratio (SNR or SIR).

Inner loop power control means that the output power of the mobile communication system is integratedly controlled as described above, and setting the range of the interloop power control range is performed by an outer loop or an outer loop. It is called power control and is applied to both the case where the base station controls the output power of the terminal and the terminal controls the output power of the base station.

The external loop power control apparatus of the base station 10 according to the general mobile communication system is configured to input and set a target quality value for smooth communication of the terminal 20 and at the same time, the terminal according to the reception state information reported by the terminal 20. A target unit 30 for outputting a signal-to-noise ratio SIR _target preliminary target value SIR _{target (k)} of 20, and a preliminary target value SIR _{target (k)} applied from the target unit 30; A limiter 40 for _inputting and outputting a target value in a limited range so as not to exceed an upper limit target value SIR maxtarget and a lower limit target value SIR mintarget set for preventing interference with a neighboring terminal 20 and system stabilization; The output power of the terminal 20 is controlled by using the target value SIR _{target (k)} limited by the limiter 40 and the measured signal-to-noise ratio (SIR) value of the terminal 20. Power control outputting signal (TRANSMIT POWER CONTROL: TPC) A transmission unit 60 for outputting the output power control signal TPC applied from the power control unit 50 to the terminal 20 wirelessly through an antenna, and a signal received from the terminal 20. The receiver 70 detects a Cyclic Redundancy Check (CRC) value and outputs the received signal to the target unit 30 as reception state information. It is composed. According to one example as described above, the terminal 20 under the external loop power control of the base station 10 includes a receiver 26 for analyzing and outputting an output power control signal (TPC) by analyzing a signal received by an antenna; The power adjusting unit 24 outputs a signal for controlling the output power of the terminal 20 by analyzing the output power control signal TPC applied from the receiving unit 26 and the terminal 20 to transmit. A transmitter 22 which processes and outputs a signal corresponding to the signal, and an amplifier 28 whose amplification factor is controlled by a control signal inputted from the power adjuster 24 to the signal input from the transmitter 22. .

The power control process occurring between the power control unit 50, the transmitter 60, the receiver 70, and the terminal 20 of the base station 10 is called an inner loop power control (INNER LOOP POWER CONTROL). It is called OUTER LOOP POWER CONTROL to set the power control target range that occurs between 30 and the limiter 40.

The target quality value applied to maintain the quality of the link is applied to the target unit 30 from the corresponding control unit of the base station 10, and the target unit 30 is a signal received from the terminal 20. By receiving a CRC signal confirming a bit error and analyzing the received state information, the block error rate (BLER) is used to determine a preliminary target value (SIR target (k)) of the signal-to-noise ratio that the terminal 20 should output. Output to the limiter 40 so as to satisfy the Block Error Rate).

The limiter 40 limits the preliminary target value (SIR target (k)) applied from the target unit 30 so as not to exceed a set upper limit target value and lower limit target value range, and the power control unit (2) as a final target value. 50).

The limiting unit 40 maintains each call quality constant as necessary regardless of a change in the amount of interference and a radio wave environment among a plurality of code division multiple access (CDMA) schemes using the same frequency. Limiting the output power range is called outer loop power control or outer loop power control.

Many wireless communication systems use an adaptive transmit power control algorithm. In such a system, the same high frequency spectrum may be shared for multiple communications. When receiving a particular communication, all other communications using the same spectrum cause interference for that particular communication. As a result, raising the transmit power level of one communication lowers the signal quality of all other communications within that spectrum. However, if the transmission power is lowered too much, the received signal quality becomes undesirable when the signal-to-interference ratio (SIR) is measured at the receiver.

Conventionally, when an error of data occurs, the target value SIR _target is increased by a delta value. However, even if the data error occurs for about 0.5 seconds due to the poor channel environment in the actual wireless environment, the SIR _target of the outer loop power control (OLPC) operates at the maximum value. However, in a harsh environment, the other party may appear to be difficult to operate the OLPC correctly. Even if the channel environment is restored, all UP Power Control information is transmitted to satisfy the maximum target value (SIR _target ), but the base station transmits downlink power control. The specification disables sudden power control, which results in poor channel response and performance degradation.

An object of the present invention is to provide an outer loop power control (OLPC) method that can cope with channel degradation in a wireless communication system.

Another object of the present invention is to improve call quality.

It is still another object of the present invention to provide a method capable of appropriately operating a target signal value of outer loop power control in order to provide quality service.

In the outer loop power control method according to the present invention, in the outer loop power control method of a wireless communication system for transmitting data to a block through a communication channel and performing channel transmission control using the received block error rate information of the data block, It is characterized by determining whether to operate the outer loop power control according to the channel environment.

A detailed feature of the outer loop power control method according to the present invention is to determine the normal or abnormal of the channel environment by measuring the energy of the dedicated physical control channel (DPCCH).

Another detailed feature of the outer loop power control method according to the present invention is that the normal or abnormal channel environment is determined depending on whether the energy of the dedicated physical control channel (DPCCH) corresponds to the currently set SIR target value. It is a point.

Another aspect of the outer loop power control method according to the invention comprises the steps of determining whether an error occurs; Determining whether an energy of a dedicated physical channel is enough to be applied to a currently set target value (SIR _target ) when an error occurs; Correcting the next target value if it is applicable and increasing the provisional delta value if it is not applicable; If an error has not occurred, correcting a next target value and determining whether a provisional delta value exists; If there is a provisional delta value, then the step includes modifying the next target value.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described by at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

The present invention is applicable to a UMTS terminal. In order to satisfy the QoS, the signal-to-noise ratio target (SIR _target ) of the external loop power control (OLPC) must be properly operated.

Therefore, how to operate the signal-to-noise ratio target value (SIR _target ) is an issue, and the present invention relates to an improved signal-to-noise ratio target value (SIR _target ) operation algorithm.

In the real wireless environment, when the other party cannot perform the outer loop power control (OLPC) function properly due to the poor channel environment, the energy of the dedicated physical control channel (dpcch) does not correspond to the current signal-to-noise ratio (SIR _target ) appropriately. I can't. In this case, the operation of the OLPC is stopped (Stop Algorithm), and the operation of the OLPC is resumed when the counterpart can correctly perform the OLPC function (GO Algorithm). Here, the other party is a terminal from the viewpoint of the base station, and a base station from the viewpoint of the terminal. Therefore, the present invention is applicable to a terminal as well as a base station.

2 is a flow chart showing the progress of the outer loop power control method according to the present invention.

It is determined whether an error occurs (S21), and if an error occurs, it is determined whether the energy of the dedicated physical channel can be applied to the currently set target value (SIR _target ) (S22).

과 같다(S24).If applicable, the next target value is corrected by adding a provisional step-up value to the current target value. If you represent this as a formula

Same as (S24).

If not applicable, the provisional delta value Δ is increased (S23).

과 같이 나타낼 수 있다(S25).If no error occurs, correct the next target value. At this time, the target value can be modified

It can be represented as (S25).

과 같이 수정한다.Subsequently, it is determined whether there is a provisional delta value (S26), and if there is a provisional delta value, the next target value is determined.

Modify it as follows.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

As described above, by determining whether to apply the OLPC in accordance with the channel state according to the present invention has the effect of improving the quality of the call quality. In addition, there is an effect that can cope with the channel degradation of the wireless communication system.

Claims (7)

Measuring energy of a dedicated physical control channel (DPCCH); Determining whether the measured value corresponds to a currently set SIR target value; The method of controlling the outer loop power of the wireless communication system, characterized in that it is determined whether to operate the outer loop power control according to the communication channel environment. delete delete The method of claim 1, wherein the wireless communication system is a universal mobile telecommunication system (UMTS). A first step of determining whether an error occurs by checking a signal-to-noise ratio of a signal received through a communication channel; A second step of determining whether the energy of the dedicated physical channel is enough to be applied to the currently set target value (SIR _target ) when an error occurs; Modifying the next target value if it is applicable and increasing the provisional delta value if it is not applicable; If an error does not occur, correcting the next target value and determining whether a provisional delta value exists; And a fifth step of modifying the next target value, if there is a provisional delta value. The method of claim 5, wherein the next target value in the third step, A method of controlling an outer loop power of a wireless communication system according to claim 1, wherein the current target value is modified by adding a provisional step up value. The method of claim 5, wherein the next target value in the fourth step, And a down step value is added to a current target value to modify the outer loop power control method of the wireless communication system.

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