KR20020070740A - Apparatus and method for correcting transmission power of base station in mobile telecommunication system - Google Patents

Abstract

PURPOSE: An apparatus and method for correcting the transmitting output of a base station is provided to perform the transmitting output correction function of the base station while calls are serviced in a mobile communication system. CONSTITUTION: A real output measuring unit(228) receives a signal transmitted from a base station and measures a real output of the base station. A reference output measuring unit(230) measures a current reference output of the base station. A base station diagnosing unit(224) controls measurement operation times of the real output measuring unit(228) and the reference output measuring unit(230), calculates the difference of the real output and the reference output, and determines an output correction value. A transmission output changing unit(232) corrects the output transmitted from the base station by the output correction value.

Description

Device and method for compensating transmission power of base station {APPARATUS AND METHOD FOR CORRECTING TRANSMISSION POWER OF BASE STATION IN MOBILE TELECOMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for controlling an output of a base station of a mobile communication system, and more particularly, to an apparatus and method for compensating a transmission output of a base station in a service state.

In general, the transmission power correction function of the base station in a mobile communication system was not possible while serving a call. This is because the output of the base station is variable after the call is established between the terminal and the base station by power control between the base station and the terminal of the mobile communication system. That is, the output of the base station is changed by various reasons such as the distance between the terminal and the base station, the radio wave mirror, and the interference with neighboring base stations. Therefore, although the actual transmission output of the base station for transmission output correction could be measured using the base station transmission output measurement equipment, it is difficult to set the reference transmission output value by the power control during the service of the call.

Therefore, conventionally, the transmission output is corrected by setting the baseline output value for transmission output correction as the base station output without a call. That is, the base station outputs without a call, only a pilot channel, a sync channel, and a paging channel are serviced, and a traffic channel is not used. Therefore, since the output of the base station is constant because it does not perform a power control function with the terminal, it can be set as a reference output value for transmission output correction. In this case, the transmission power of the base station is measured using measurement equipment, and compared with the inferred reference output by the calculation of the measured value, and if the difference exists within a predetermined criterion, the output of the base station is equal to the reference output. Changed.

1 is a diagram illustrating a process of correcting a transmission power of a base station in a conventional mobile communication system.

Referring to FIG. 1, in step 111, the TSM requests a transmission output correction function to the BTH. The BTH then reports to the TSM that it cannot perform the function if it is in the call service unless the operator requests the mandatory call restriction function. However, if the call restriction function is required, the BTH requests the call processing block to set the call restriction function in step 112. In this case, when the BTH requests call restriction, the call processing block releases all the calls set in step 113 and reports the result as BTH. When the call is normally released, the BTH requires the base station to measure the actual output of the base station in step 114. Accordingly, the BTU reports the value of the base station to the BTH after measuring the output of the base station according to the request of the BTH in step 115. do.

Then, in step 116, if the base station output measurement value of the BTU is normal, the BTH calculates a reference output for transmission output correction. In this case, the calculated reference output is the transmission output value of the base station when the call service is not performed. Thereafter, the BTU requests the call processing block to release the set call restriction in step 117. Accordingly, the call processing block releases the call restriction in step 118 and reports the result to the BTH. Then, the BTH compares the calculated reference output with the output value measured by the BTU to determine whether to correct the transmission output. When performing the correction of the transmission output, the BTH requests the transmission output change to TRXA in step 119. The TRXA reports the transmission output change result to the BTH in step 120, and the BTH reports the reported transmission output correction result to the TSM in step 121.

The conventional transmission output correction method of the base station is an output when the pilot channel, the synchronization channel, and the paging channels are the reference output for the transmission output correction, the output of the base station using the base station transmission output measurement equipment Only the pilot channel, synchronization channel, and paging channel should be serviced. This means that there should be no call set up at the base station during the time of measuring the actual output for the transmit power correction function.

However, it is very difficult to perform a functional test during a time when there is no call during the operation of the system. Therefore, since it is impossible to perform a function by searching for a time without call service, there is a method of performing a function test after releasing a call that is forcibly allocated for the transmission output correction and making the call disappear. However, if this method is used, there is a problem in that the allocated call must be released for testing the transmission power correction function.

Accordingly, an object of the present invention is to provide an apparatus and method capable of performing a transmission output correction function of a base station while a call is in service in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for determining a reference output in a state where a call exists in a mobile communication system, and correcting a current base station output to a reference output to minimize a change in a call service area according to a change in base station output. In providing.

An apparatus for correcting the transmission output of the base station of the mobile communication system according to an embodiment of the present invention for achieving the above object, the actual output measuring unit for measuring the actual output of the base station by inputting a signal transmitted from the base station, and the current of the base station A base station diagnosis unit for controlling a measurement output time of a reference output measurement unit for measuring and calculating a reference output, and an operation time of the actual output measurement unit and the reference output measurement unit, and determining an output correction value by calculating a difference between the received measured actual output and a reference output. And a transmission output changing section for correcting the output transmitted from the base station by the output correction value.

1 illustrates a conventional method of correcting a transmission power of a base station in a mobile communication system.

2 is a diagram illustrating a structure for correcting a transmission power of a base station according to an embodiment of the present invention in a mobile communication system.

3 is a view for explaining an operation of measuring a transmission power using a base station diagnostic unit in a mobile communication system;

4 is a view for explaining an operation of measuring the strength of the signal input to the base station diagnostic unit in the mobile communication system;

5 is a diagram illustrating a method of correcting a transmission power of a base station according to an embodiment of the present invention in a mobile communication system.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The elements of radio frequency devices (e.g. LPA (Linear Power Amplifier), TRXA, antenna cable, etc.) of the base station of the mobile communication system are passive devices. The passive element does not perform its original function over time, and performance deteriorates little by little due to deterioration. Therefore, as the transmission power of the base station determined by the passive elements is operated, the output change occurs due to the deterioration of the device. Accordingly, the optimized call service area of the initial base station is changed, thus making it difficult to perform normal base station call service. Lose.

The mobile communication system for solving this problem has a function of correcting the transmission output of the base station. The transmit power correction function of the base station automatically corrects the change in the base station transmit power caused by the deterioration of the wireless devices of the base station, and thus can continuously optimize the call service without changing the call service area of the initially optimized base station. have. In addition, since the output change of the base station can be automatically corrected according to the replacement of the base station radio, the change of the base station call service area due to the change of the radio can be minimized.

2 is a diagram illustrating a structure for correcting a transmission output of a base station according to an embodiment of the present invention.

Referring to FIG. 2, the control station / base station manager 222 is the highest configuration that performs the diagnostic functions of the control station and the base station, and reports the result of requesting transmission output correction to the operator. The control station / base station manager 222 is hereinafter referred to as TSM222. The base station diagnosis unit 224 is configured to perform a diagnostic test function of the base station. The base station diagnosis unit 224 performs a function in association with each of the components according to the function execution request of the BSM222, and reports the result of performing the function to the BSM222. The actual output measuring unit 228 measures the actual output of the base station, requests an output to the reference output measuring unit 230, and requests the output change unit 232 to output as much as the difference between the reference output and the actual output. Hereinafter, the actual output change unit 228 is referred to as BTU228. The reference output measuring unit 230 measures and calculates a current reference output of the base station. Hereinafter, the reference output measuring unit 230 is referred to as CEC. The transmission output changing section 232 changes the output of the base station at the request of the BTU. Hereinafter, the transmission output changer 232 will be referred to as TRXA. The GPS226 processes the satellite's time data and periodically reports the system counter value and system time of data (TOD) to BTU228 and CEC230 in 1.25ms and 20ms units.

Looking at the above structure, the TSM222 requires the BTH224 transmit power correction function. The BTH224 then requests a reference output from the CEC230 and receives the result to correct the reference output to the actual output of the base station, and requests the output of the current base station from the BTU228 and receives the measurement result. The GPS226 outputs time data TOD to the BTH224 and the CEC230, respectively. The BTH224 then requests the TXRA232 to change the transmit power and receives the result to correct the actual output value to a reference output value and reports the transmit power correction result to the TSM.

First, a transmission power measurement operation of a base station using a BTU will be described with reference to FIGS. 3 and 4.

If the transmission output of the base station is directly specified, the call cannot be serviced, and thus an indirect method as disclosed in FIG. 3 is used. That is, a directional coupler 313 is connected between the TXRA232 and the antenna 311, so that some of the transmission outputs output to the antenna 311 are combined and transmitted to the BTU228. The BTU228 then changes the IF (Intermediate Frequency) for measuring the combined signal and measures the intensity of the transmission output through an analog to digital converter (ADC).

4 illustrates a structure for measuring the strength of a signal input to the transmission power measurement BTU230. Referring to FIG. 4, when signals are combined through the directional coupler 313, the switch 1 (SW1) 422 for separating the measurement into a desired sector and the switch 2 (SW2) 424 for distinguishing the strength of other sector signals are passed through. do. In this case, the signal passing through the switches is amplified by about 15 dB in the low noise amplifier (LNA) 426 because the signal strength of the directional coupler and the switches is reduced. In addition, an RF SAW path filter 428 performs a filter operation to remove an unnecessary signal from the amplified signal, and is mixed with an output of a frequency synthesizer 430 in a down converter 432 to an IF signal. It changes downward. The down-converted IF signal is filtered in the filter (1.25MHz SAW) and then the intensity is detected in the detector 436, and then changed to a digital value in the ADC438. At this time, each digital value is changed to the value (Watt) defined according to the output level, and then the path loss from the directional coupler 313 to the ADC438 is added to become the transmission output of the base station.

Second, we look at the operation of obtaining the reference output using the CEC230.

The CEC230 can determine the output level of the call channel by interworking with the channel in charge of the base station call service. The output of the base station is determined according to the digital gain of the pilot channel, synchronization channel, paging channel, traffic channel, and the like. The digital gain of the base station pilot, synchronization, and paging channel is operated at a constant value, but the digital gain of the traffic channel is varied by power control between the base station and the terminal. That is, when the radio environment between the base station and the terminal is poor, the digital gain of the traffic channel between the terminal and the base station increases, and vice versa. The output of the base station therefore depends on the digital gain of the traffic channel between the base station and the terminal serving the call.

The output of the base station is determined as follows.

The output of an overhead channel (pilot, sync, paging channel) is shown in Equation 1 below.

In Equation 1

A: Base station output when Pilot DG = 127, Pilot channel only

Pilot DG: Pilot channel digitla gain

Sync DG: Sync channel digital gain

PagingN DG: N`th Paging channel digital gain

N: Number of Equipped paging channels

Paging rate: 4800bps = 1/2, 9600bps = 1

In addition, the output calculation for one call is shown in Equation 2 below.

Where A: Base station output when Pilot DG = 127, Pilot channel only

voice activity: 0-1

Therefore, the total transmission power of the base station is as shown in Equation 3 below.

As described above, the CEC230 determines the output of the base station regardless of the current call service by identifying the digital gain of the traffic channel in conjunction with each traffic channel.

5 is a diagram illustrating a process of correcting a transmission output of a base station in a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 5, when an operator's measurement request is generated, the TSM222 requests BTH224 to transmit transmission correction in step 511. Then, the BTH224 determines the test start time plus the current system time message transmission time according to the TSM222 transmission power correction request, and then, in step 513, requires the CEC230 to measure the reference output and the BTU228 in step 515 to measure the transmission power. Requires. That is, the BTH224 transmits an output measurement time and a measurement request message to the BTU228 and CEC230 to measure the respective reference output and the actual output at the test start time. The BTH224 performs a function irrespective of a request for performing a transmission output correction function of the TSM222 or a request by a periodic function.

Then, the CEC230 measures the base station reference output of the test start time determined by the BTH224 at the request of the BTH224, and reports the reference output measurement result to the BTH224 in step 517. The BTU228 measures the base station actual power of the test start time determined by the BTH224 at the request of the BTH224, and reports the reference output measurement result to the BTH224 in step 519.

Thereafter, the BTH224 compares the reference output of the CEC230 and the actual output of the BTU228, and when the difference between the two outputs corresponds to the correction range, corrects the actual output as the reference output by the difference between the two outputs. In operation 521, the BTH224 outputs a correction value, which is a difference between the reference output and the actual output, to the TXRA232. The TXRA232 then changes the correction value in the actual output according to the output change request of the BTH224, and reports the change result to the BTH224 in step 523. In operation 525, the BTH224 reports the result of performing the transmission output correction function to the TSM222 and terminates the correction operation of the transmission output.

Therefore, as described above, the transmission output correction function of the base station according to the embodiment of the present invention automatically corrects the change of the base station transmission power due to deterioration of the wireless devices of the base station, thereby changing the initial optimized call service area of the base station. It can provide continuous optimized call service. In addition, since the output change of the base station can be automatically corrected according to the replacement of the base station radio, there is an advantage of minimizing the change of the base station call service area due to the change of the radio.

Claims (8)

An apparatus for correcting a transmission output of a base station of a mobile communication system, An actual output measuring unit measuring an actual output of the base station by inputting a signal transmitted from the base station; A reference output measuring unit for measuring and calculating the current reference output of the base station; A base station diagnosis unit for controlling a measurement operation time of the actual output measurement unit and the reference output measurement unit, and determining an output correction value by calculating a difference between the measured actual output and the reference output; And a transmission output changer configured to correct an output transmitted from the base station based on the output correction value. The method according to claim 1, wherein the base station diagnosis unit determines a test start time obtained by adding a message transmission time to a system time in response to a transmission output correction request of the base station manager, and then output measurement time and measurement request to the actual output measurement unit and the reference output measurement unit. Transmission output correction apparatus for a mobile communication system, characterized in that for controlling the measurement by transmitting a message. 3. The apparatus of claim 2, further comprising a directional coupler connected to an output of a base station transmitter, wherein the actual output measurement unit measures an actual output of a transmission signal coupled from the directional coupler. The apparatus of claim 2, wherein the reference output measurement unit calculates the output of the overhead channels and the output of each of the variable traffic channels, and then calculates the reference output of the base station by adding them. In the transmission output correction method of the base station of the mobile communication system, A process of generating and sending a measurement request message to an actual output measurement unit and a reference output measurement unit when transmission output correction is necessary; Calculating a difference between the actual output and the reference output reported by the actual output measuring unit and the reference output measuring unit, respectively, and outputting the correction value as the correction value to the transmission output changing unit; And transmitting and displaying the result of the corrected transmission output to the transmission output changing unit. The method of claim 5, wherein the step of generating the measurement request message determines the test start time of the system time plus the message transmission time in response to the transmission output correction request of the base station manager, and then generates the measurement request message. A transmission output correction method of a mobile communication system, characterized in that. 7. The method of claim 6, wherein the measuring of the actual output measures an actual output of a transmission signal coupled by a directional coupler connected to an output of a base station transmitter. The method of claim 6, wherein the step of measuring the reference output, The process of obtaining the output of the overhead channel in Equation (4), The process of obtaining the output of one traffic channel by Equation 5 below, And calculating a reference output of the base station by using Equation 6 using the outputs of the overhead channels and the traffic channel. A: Base station output when Pilot DG = 127, Pilot channel only Pilot DG: Pilot channel digitla gain Sync DG: Sync channel digital gain PagingN DG: N`th Paging channel digital gain N: Number of Equipped paging channels Paging rate: 4800bps = 1/2, 9600bps = 1 A: Base station output when Pilot DG = 127, Pilot channel only voice activity: 0-1