KR20020035719A - Device and method for controlling reverse power in mobile communication system - Google Patents

Abstract

PURPOSE: A system and a method for controlling closed loop power in a mobile system are provided to previously prevent call cutoff and the deterioration of tone quality by preventing the congestion of reverse power from being generated. CONSTITUTION: A system for controlling closed loop power in a mobile system consists of a base station controller(100) and a plurality of base stations(200). The base station controller(100) includes an operation/management block(110). Each base station(200) includes a plurality of channel elements(211). The operation/management block(110) contains a reference Eb/No table storing reference Eb/No values. The operation/management block(110), measuring the capacity of each base station(200) periodically, reads a reference voice Eb/No value corresponding to each capacity and an offset value for each data speed from the reference Eb/No table and transmits them to the channel elements(211) of each base station(200). The reference Eb/No table is composed of a standardized capacity field, a reference voice Eb/No field, and a data offset field. The standardized capacity field stores the standardized capacity values of base station #1 through #N. The reference voice Eb/No field stores reference voice Eb/No values respectively corresponding to the standardized capacity values stored in the standardized capacity field. The data offset field stores data speed offset values respectively corresponding to the standardized capacity values stored in the standardized capacity field.

Description

Reverse closed loop power control device and method thereof in mobile communication system {DEVICE AND METHOD FOR CONTROLLING REVERSE POWER IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a reverse closed loop power control apparatus and method thereof in a mobile communication system. More particularly, the present invention relates to a signal-to-noise ratio (hereinafter, " Eb / No ") as a reference for power control to correspond to a change in capacity of a base station. The present invention relates to a reverse closed loop power control device and a method in a mobile communication system which prevents a saturation phenomenon of a reverse power, which is a terminal output power, by appropriately changing a value.

As is well known, in the mobile communication system, a unique algorithm called power control has been used to solve the root problem of the terminal station, thereby increasing the capacity.

This power control can be largely divided into forward power control and reverse power control, respectively, and controls output power for each channel of the base station and the terminal station. In this case, the backward closed loop power control is performed by controlling the Eb / No value of the terminal station transmit power measured by the channel element of the base station.

In the conventional mobile communication system, the reverse closed loop power control apparatus is mounted in a plurality of channel cards 11 of the base station 10 and is one-to-one with the terminal station 1, respectively, as shown in FIG. And a plurality of channel elements 11a which are connected and perform a call processing function and a power control function with the terminal station 1.

Next, a backward closed loop power control method in a conventional mobile communication system will be described with reference to FIG. 2.

First, the channel element 11a measures the transmission power from the terminal 1, and then compares the Eb / No value of the transmission power with the reference Eb / No value (S1).

At this time, if the Eb / No value of the transmission power of the terminal 1 currently measured in the first step S1 is greater than the reference Eb / No value (YES), the channel element 11a is powered by the terminal 1. A decrease command signal is output (S2).

On the other hand, when the Eb / No value of the transmission power of the terminal 1 currently measured in the first step S1 is smaller than the reference Eb / No value (NO), the channel element 11a is connected to the terminal 1. Outputs a power increase command signal (S3).

In this case, the meaning and calculation method of the above-mentioned reference Eb / No used as the power control variable will be described. The reference Eb / No represents the total noise power versus the energy per bit of the magnetic channel. It is used instead of the signal-to-noise ratio (C / N) that was used in. The relationship between the signal-to-noise ratio (C / N) and Eb / No is shown in Equation 1 below.

C / N + (Processing Gain) = Eb / No

Herein, the processing gain represents a gain generated by despreading in a code division multiple access (CDMA) data coding process, which can be expressed by Equation 2 below.

Processing Gain = (Bandwidth) / (Data Rate)

Herein, the voice data rate in the CDMA mobile communication is 9.6 (Kbps), and the bandwidth is 1.2288 (MHz), so the processing gain is about 21 (dB). Therefore, it can be considered that the Eb / No value in the digital domain of any one channel is proportional to the C / N value in the analog domain, so if the noise figure generated inside the system can be ignored, The power control with No as a reference value can be considered the same as the power control with the C / N value at the input of the system. At this time, in the C / N value of the system input terminal, "C" may be expressed as the base station input power of the channel to be controlled, and "N" is "equivalent thermal noise at the base station input terminal + other channel interference in its base station + Interference of other base station channels plus other interferences ".

Looking at the noise power density "N" in more detail, first, the interference of other base station channels and other interferences will be treated as a constant offset value for simplicity of calculation. Assuming that power control is completely performed, the input power to the base station for each channel can be assumed to be constant. Therefore, when the capacity is "n", the size can be calculated as "(n-1) x C". Finally, the equivalent thermal noise at the base station input is assumed to be "-100 (dBm / 1.25M)" in consideration of the noise figure of the system. In this case, the power control variable Eb / No is calculated using Equation 3 below when the user n per cell is small, and is calculated using Equation 4 below when the user n per cell is large. do.

Eb / No = C / KTB + (n-1) + 21

Here, "KTB" means thermal noise.

Eb / No = 1 / (n-1) + 21

On the other hand, the increase rate of the terminal station output power according to the increase of the capacity of the conventional algorithm described above represents a large increase rate of about 0.7 when the reference Eb / No value is fixed to 6 (dB), as shown in FIG.

However, the above-described closed closed loop power control method in the conventional mobile communication system performs power control using a fixed reference Eb / No value regardless of the capacity of the base station, so that the base station Eb / No value increases when the capacity of the base station increases. The input power value of the base station for maintaining the power is exponentially increased, which causes the interference power between the terminal stations on the same path loss increases exponentially, causing the saturation of the terminal station output power. . At this time, in general, the saturation phenomenon of the terminal station output power is a phenomenon likely to occur when the increase rate of the terminal station output power according to the increase in capacity is large, as shown in FIG.

Therefore, due to the above-mentioned problem, frequent disconnection of the call and deterioration of the call quality occur, and thus, the mobile communication service provider cannot provide higher quality services to users, and thus, the competitiveness with other operators is inferior. there was.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent the occurrence of frequent disconnection of the call and the sound quality of the call by preventing the saturation of the reverse power, which is the terminal output power. The present invention provides a reverse closed loop power control device and a method thereof in a mobile communication system.

In order to achieve the above object, a reverse closed loop power control apparatus in a mobile communication system of the present invention has a built-in reference Eb / No table in which a reference Eb / No value is stored according to a capacity change, and periodically A control station having an operation / management block for reading and transmitting a reference voice Eb / No value and an offset for each data rate from the reference Eb / No table; And

It is installed in a plurality of channel cards, respectively, and periodically receives reference voice Eb / No information and offset information for each data rate according to capacity change from the operation / management block in the control station, and then uses the received information to receive voice and each data. After setting the reference Eb / No value for each individual, and then calculate the Eb / No value of the current terminal station transmission power, and performs the reverse power control operation by comparing the Eb / No value of the current terminal station and the reference Eb / No value It is characterized by consisting of a plurality of base stations each having a plurality of channel elements.

In addition, the method for controlling the reverse closed loop power in the mobile communication system includes: a step 100 of initializing various reference Eb / No values by a channel element in a base station initializing a reference Eb / No reception period timer;

A step 200 in which the channel element receives reference voice Eb / No information and offset information for each data rate according to a base station capacity change from an operation / management block in a control station;

The channel element calculates and sets a reference voice Eb / No value and a reference Eb / No value for each data rate by using reference voice Eb / No information according to a change in base station capacity and offset information for each data rate step;

Step 400, wherein the channel element calculates an Eb / No value of a current terminal station output power;

Step 500, the channel element determining whether an Eb / No value of a current terminal station output power is larger than a corresponding reference Eb / No value;

Step 600, when the Eb / No value of the current terminal station output power is greater than a corresponding reference Eb / No value in step 500, the channel element transmitting an output power reduction command to the terminal station; And

The channel element determines whether the current time point is the reference Eb / No reception period, and if the current time point is not the reference Eb / No reception period, the process proceeds to step 400; Characterized in that it comprises a 700 step proceeds to the 200 step.

1 is a functional block diagram showing the configuration of a reverse closed loop power control device in a conventional mobile communication system;

FIG. 2 is an operation flowchart illustrating a reverse closed loop power control method in the conventional mobile communication system according to FIG. 1;

3 is a view showing a change in terminal station output power with increasing capacity in the reverse closed loop power control method in the conventional mobile communication system according to FIG.

4 is a functional block diagram showing a configuration of a reverse closed loop power control apparatus in a mobile communication system according to an embodiment of the present invention;

FIG. 5 is a view showing a state of a reference Eb / No table embedded in an operation / management block in a control station in a reverse closed loop power control device in the mobile communication system according to FIG. 4;

6 is an operation flowchart illustrating a reverse closed loop power control method in a mobile communication system according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating a change in terminal station output power according to capacity increase in the reverse closed loop power control method in the mobile communication system according to FIG. 6.

<Explanation of symbols for the main parts of the drawings>

100: control station 110: operation / management block

111: reference Eb / No table 111a: standardized capacity area

111b: reference voice Eb / No area 111c: data offset area

200: base station 210: channel card

211: channel element

Hereinafter, a reverse closed loop power control apparatus and a method thereof in a mobile communication system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a functional block diagram of a reverse closed loop power control apparatus in a mobile communication system according to an embodiment of the present invention, the reverse closed loop power control apparatus in a mobile communication system according to an embodiment of the present invention is operated / A control station 100 having a management block 110 and a plurality of base stations 200 each having a plurality of channel elements 211.

The operation / management block 110 mounted in the control station 100 has a built-in reference Eb / No table 111 in which a reference Eb / No value is stored according to the capacity change of the base station 200, and periodically itself. The capacity of the base station 100 to be managed is measured, and the reference voice Eb / No value corresponding to the capacity and the offset for each data rate are read from the reference Eb / No table 111, and then a plurality of them managed by the user. Each of the plurality of channel elements 211 in the base station 200 serves to transmit.

In this case, the reference Eb / No table 111 stored in the operation / management block 110 stores the standardized capacity value 111a of the base station 100 from 1 to N as shown in FIG. 5. ), A reference voice Eb / No area 111b for storing reference voice Eb / No values corresponding to 1 to N standardized capacity values stored in the standardized capacity area 111a, and the standardized capacity area 111a. It consists of a plurality of data offset areas 111c for storing a plurality of data rate offset values respectively corresponding to the standardized capacity values of 1 to N stored in the.

Here, the standardized capacity values of 1 to N stored in the standardized capacity region 111a are values defined by Equation 5 below based on one call of 9.6 Kbps voice, respectively.

Normalized capacity value = one voice call (9.6 Kbps) × N

In addition, a plurality of channel elements 211 respectively mounted in the plurality of base stations 200 are mounted in the plurality of channel cards 210, respectively, to change the capacity from the operation / management block 110 in the control station 100. Periodically receive reference voice Eb / No information and offset information for each data rate, and then set the reference Eb / No values for each voice and each data using the received information, and then transmit power of the current terminal station (1). The Eb / No value is calculated, and the Eb / No value of the current terminal station 1 is compared with the reference Eb / No value to perform a reverse power control operation.

Then, referring to FIGS. 6 and 7 for a method for controlling the reverse closed loop power in the mobile communication system according to an embodiment of the present invention using the reverse closed loop power control device in the mobile communication system having the above configuration. Let's explain.

First, the channel element 211 in the base station 200 initializes the reference Eb / No reception period timer and initializes various reference Eb / No values (S100). Here, the reference Eb / No reception period timer is a timer that checks the period for receiving the reference Eb / Nb value and the offset from the control station 100.

Then, the channel element 211 receives reference voice Eb / No information and offset information for each data rate according to the capacity change of the base station 100 from the operation / management block 110 in the control station 100 ( S200).

Subsequently, the channel element 211 uses the reference voice Eb / No information and the offset information for each data rate according to the capacity change of the base station 100, and the reference voice Eb / No value and the reference Eb / No value for each data rate. After calculating the set (S300). At this time, the reference Eb / No value for each data rate described above is calculated using Equation 6 below.

Eb / No value for each reference data rate = reference voice Eb / No value + offset

In Equation 6, the Eb / No value for each reference data rate refers to an Eb / No value according to the type of data (64 Kbps and 128 Kbps) that the base station 200 can process, and the offset refers to each reference data. It means the compensation value to get the Eb / No value for each speed.

Thereafter, the channel element 211 calculates an Eb / No value of the current terminal station 1 output power (S400).

Subsequently, the channel element 211 determines whether the Eb / No value of the current terminal station 1 output power is larger than the corresponding reference Eb / No value (S500).

In this case, when the Eb / No value of the current terminal station 1 output power is greater than the corresponding reference Eb / No value (YES) in step 500, the channel element 211 returns to the terminal station 1. The output power reduction command is transmitted (S600).

Thereafter, the channel element 211 determines whether the current time point is the reference Eb / No reception period, and if the current time point is not the reference Eb / No reception period (NO), the process proceeds to step 400 (S400). On the other hand, if the current time point is the reference Eb / No reception period (YES), the process proceeds to the 200 step (S200) (S700).

On the other hand, if the Eb / No value of the output power of the current terminal station 1 is less than the corresponding reference Eb / No value (NO) in step 500 (S500), the channel element 211 is connected to the terminal station 1. In step S800, the control unit transmits an output power increase command.

Therefore, according to the present invention described above, the increase rate of the output power of the terminal station 1 according to the increase in capacity is about 0.3 when the reference Eb / No value is fixed to the reference Eb / No value of FIG. 6 as shown in FIG. 7. As a result, the saturation phenomenon of the output power of the terminal station 1 can be prevented.

As described above, the apparatus for controlling the reverse closed loop power in the mobile communication system according to the present invention and the method thereof prevent frequent saturation of the reverse power, which is the terminal output power, so that frequent disconnection and poor voice quality of the call are reduced. There is an excellent effect that can prevent the phenomenon in advance.

Claims (6)

Built-in standard Eb / No table that stores standard Eb / No value according to capacity change, and periodically reads reference voice Eb / No value according to capacity change and offset for each data rate from the standard Eb / No table A control station having an operation / management block for transmitting; And It is installed in a plurality of channel cards, respectively, and periodically receives reference voice Eb / No information and offset information for each data rate according to capacity change from the operation / management block in the control station, and then uses the received information to receive voice and each data. After setting the reference Eb / No value for each individual, and then calculate the Eb / No value of the current terminal station transmission power, and performs the reverse power control operation by comparing the Eb / No value of the current terminal station and the reference Eb / No value Reverse closed loop power control apparatus for a mobile communication system, characterized in that composed of a plurality of base stations each having a plurality of channel elements. The method of claim 1, The reference Eb / No table mounted in the operation / management block includes: a standardized capacity area for storing standardized capacity values of base stations from 1 to N; A reference voice Eb / No area for storing reference voice Eb / No values corresponding to 1 to N standardized capacity values respectively stored in the standardized capacity area; And Reverse closed loop power control in a mobile communication system comprising a plurality of data offset regions respectively storing a plurality of data rate offset values corresponding to 1 to N standardized capacitance values stored in the standardized capacitance region Device. The method of claim 2, The standardized capacity values of 1 to N stored in the standardized capacity area are each defined by Equation 5 below based on one call of 9.6 Kbps voice. [Equation 5] Normalized capacity value = one voice call (9.6 Kbps) × N A step 100 of initializing various reference Eb / No values while initializing a reference Eb / No reception period timer by a channel element in a base station; A step 200 in which the channel element receives reference voice Eb / No information and offset information for each data rate according to a base station capacity change from an operation / management block in a control station; The channel element calculates and sets a reference voice Eb / No value and a reference Eb / No value for each data rate by using reference voice Eb / No information according to a change in base station capacity and offset information for each data rate step; Step 400, wherein the channel element calculates an Eb / No value of a current terminal station output power; Step 500, the channel element determining whether an Eb / No value of a current terminal station output power is larger than a corresponding reference Eb / No value; Step 600, when the Eb / No value of the current terminal station output power is greater than a corresponding reference Eb / No value in step 500, the channel element transmitting an output power reduction command to the terminal station; And The channel element determines whether the current time point is the reference Eb / No reception period, and if the current time point is not the reference Eb / No reception period, the process proceeds to step 400; The closed closed loop power control method of the mobile communication system, characterized in that it comprises a step 700 to proceed to the step 200. The method of claim 4, wherein If the Eb / No value of the current terminal station output power is less than the reference Eb / No value in step 500, the channel element transmits an output power increase command to the terminal station, and then proceeds to step 700. The method of claim 1, further comprising 800 steps. The method of claim 4, wherein The method for calculating the reference Eb / No value for each data rate by the channel element in step 300 is calculated using Equation 6 below. [Equation 6] Eb / No value for each reference data rate = reference voice Eb / No value + offset