KR20200038100A - Transmission power control device and control method thereof - Google Patents

Abstract

Disclosed in the present invention is a technique for realizing a new method for suppressing strong air-to-ground (ATG) interference generated from an aircraft terminal in consideration of the difference in radio wave attenuation characteristics and maintaining balanced performance of ground/air mobile communication services. According to an embodiment of the present invention, a transmission power control apparatus comprises: a terminal identification unit for confirming whether the amount of radio wave attenuation corresponds to a first terminal category smaller than a specific threshold attenuation amount among a plurality of terminal categories having different radio wave attenuation characteristics for a terminal accessing a service base station; and a control unit which performs uplink transmission power control for the uplink interference strength on a neighboring base station to be reduced with respect to the terminal when the terminal corresponds to the first terminal category.

Description

Transmission output control device and operation method of transmission output control device {TRANSMISSION POWER CONTROL DEVICE AND CONTROL METHOD THEREOF}

The present invention relates to a technique for controlling uplink transmission power of a terminal, and more specifically, by suppressing strong air-to-ground (ATG) interference generated from an aircraft terminal, it is possible to maintain a balanced performance of ground / air mobile communication service. It is about technology.

In the case of a mobile communication service, due to an environment characteristic in which a base station must communicate with a plurality of terminals having different distances from each other, an uplink output control to appropriately increase / decrease the uplink transmission power of the terminal according to the distance from the base station (Uplink Power Control) function.

This uplink output control is one of functions that greatly affects service quality in a mobile communication service.

In the description of the uplink output control function, the base station continuously transmits the broadcast output control setting determined by the operator by surrounding broadcasting.

At this time, the information of the transmission output control setting includes the strength of the downlink reference signal (CRS: Cell-specific Reference Signal) periodically transmitted by the base station, the target reception signal level for each uplink channel, and the propagation attenuation compensation setting.

Accordingly, a terminal that receives a transmission output control setting transmitted by broadcasting from a base station measures an amount of radio attenuation between itself and the base station based on the transmission output control setting, and uplink resource block (RB) allocated from the base station This is a method of determining the transmission power for each sub-frame (1 ms) according to the number.

This general uplink output control function operates efficiently when one base station serves only terminals having similar propagation attenuation characteristics.

On the other hand, the general uplink output control function, there is a limitation that does not operate efficiently when one base station must simultaneously service a terminal having very different radio attenuation characteristics (eg, a ground terminal, an aircraft terminal).

Specifically, a general terminal (hereinafter referred to as a ground terminal) located on the ground where it is difficult to secure a line of sight path with a base station due to an obstacle such as a building or a vehicle, and there is no obstacle to secure the LOS path with the base station relatively Airborne terminals located in easy air (eg, drones, airplanes, etc.) will have very different mutual propagation attenuation characteristics.

Due to the difference in the propagation attenuation characteristics, in the case of an air vehicle terminal, the rate of increase of radio wave attenuation (quantity) according to the distance increases slowly compared to the ground terminal, which is why the ground terminal and the air vehicle terminal have determined according to the general uplink output control function. When using a transmission output, assuming a ground / aircraft terminal spaced at the same distance, from an interference point of view to an adjacent base station, the uplink interference due to the air vehicle terminal is inevitably greater than the uplink interference caused by the ground terminal.

Therefore, considering that the rate of increase in radio wave attenuation (quantity) according to the distance is slower than that of the ground terminal in the case of an aircraft terminal, if a common uplink output control function is commonly applied to the ground / air vehicle terminal, it is adjacent at the same distance. A problem that a performance of a ground mobile communication service is relatively deteriorated may occur due to an aircraft terminal having greater interference to a base station, that is, air to ground (ATG) interference.

Accordingly, in the present invention, it is intended to propose a new method to suppress the strong air-to-ground (ATG) interference generated from the air vehicle terminal to maintain a balanced performance of the ground / air mobile communication service.

The present invention was created in view of the above circumstances, and the object to be reached in the present invention is to maintain strong balance between ground / air mobile communication service performance by suppressing strong air-to-ground (ATG) interference generated from a vehicle terminal. have.

The transmission output control apparatus according to the first aspect of the present invention for achieving the above object, a first terminal having a smaller amount of radio wave attenuation than a specific threshold attenuation amount among a plurality of terminal categories having different radio wave attenuation characteristics for a terminal connected to a service base station A terminal identification unit to check whether it corresponds to a category; And a control unit that performs uplink transmission output control for the terminal to decrease the intensity of uplink interference to an adjacent base station when the terminal corresponds to the small first terminal category.

Specifically, when the terminal corresponds to the small first terminal category, the control unit uses an estimator to estimate a downlink propagation attenuation amount between the terminal and the service base station, and an adjacent unit using the estimated downlink propagation attenuation amount. It may include a transmission output control unit for controlling the uplink transmission power of the terminal so that the uplink interference strength to the base station is reduced.

Specifically, the terminal identification unit is based on the QCI (QoS Class Identifier) granted according to the service type of the terminal, the QCI of the terminal is a specific QCI defined to be assigned to a service used in the first terminal category. You can check by terminal category.

Specifically, the transmission output control unit provides a correction value determined by using the estimated downlink propagation attenuation amount to the terminal, and the terminal is based on a transmission output control setting transmitted by the service base station by broadcasting. It can be controlled to reflect the correction value in the determined uplink transmission output.

Specifically, the transmission output control unit uses the estimated distance between the terminal and the service base station estimated based on the estimated downlink radio wave attenuation amount and the downlink signal strength transmitted by the service base station, to define a predefined radio wave attenuation model. Estimate the amount of downlink propagation attenuation for a specific terminal having the distance from the service base station, and determine the difference between the estimated amount of downlink propagation attenuation and the amount of downlink propagation attenuation for the specific terminal as the correction value, The specific terminal may be a terminal corresponding to a second terminal category in which the amount of radio wave attenuation among the plurality of terminal categories is greater than a specific threshold attenuation amount.

Specifically, the estimating unit may calculate and estimate a downlink propagation attenuation amount between the terminal and the service base station based on downlink channel quality information (CQI) reported by the terminal to the service base station.

Specifically, the estimation unit, the downlink signal-to-noise ratio (SNR) estimated based on the downlink channel quality information (CQI) and the downlink modulation technique used for the terminal, and the service By using the downlink signal strength transmitted by the base station, a downlink propagation attenuation amount for the terminal may be calculated.

A method of operating a transmission output control apparatus according to a second aspect of the present invention for achieving the above object, among a plurality of terminal categories having different propagation attenuation characteristics for a terminal accessing a service base station, the amount of propagation attenuation is smaller than a specific threshold attenuation amount A terminal identification step of checking whether it corresponds to the first terminal category; And if the terminal corresponds to a small first terminal category, a propagation attenuation estimating step of estimating a downlink propagation attenuation between the terminal and the service base station. And a transmission power control step of controlling the uplink transmission power of the terminal so that the intensity of uplink interference to an adjacent base station is reduced using the estimated downlink propagation attenuation amount.

Specifically, the transmission output control step, based on the transmission output control settings to provide a correction value determined by using the estimated downlink radio wave attenuation amount to the terminal, the terminal is broadcast (Broadcasting) transmission from the service base station It can be controlled to reflect the correction value in the predetermined uplink transmission output.

Specifically, the transmission output control step, using the estimated downlink radio wave attenuation amount and the distance between the terminal and the service base station estimated based on the downlink signal strength transmitted by the service base station, a predefined radio wave attenuation model Estimate the amount of downlink propagation attenuation for a specific terminal having the distance from the service base station, and determine the difference between the estimated amount of downlink propagation attenuation and the amount of downlink propagation attenuation for the estimated specific terminal as the correction value The specific terminal may be a terminal corresponding to a second terminal category in which the amount of radio wave attenuation among the plurality of terminal categories is greater than a specific threshold attenuation amount.

Specifically, in the estimating the amount of radio wave attenuation, the amount of downlink radio wave attenuation between the terminal and the service base station may be calculated and estimated based on downlink channel quality information (CQI) reported by the terminal to the service base station. have.

Specifically, the step of estimating the amount of radio wave attenuation is based on the downlink channel quality information (CQI) and the downlink signal-to-noise ratio (SNR) estimated based on a downlink modulation technique used for the terminal. , Using the downlink signal strength transmitted by the service base station, it is possible to calculate the amount of downlink propagation for the terminal.

Accordingly, according to the operation method of the transmission output control device and the transmission output control device of the present invention, by realizing a new method for suppressing strong ATG (Air to Ground) interference generated from the aircraft terminal, the performance of the ground / air mobile communication service It produces an effect that can be balanced.

1 is an exemplary view showing a terrestrial / air mobile communication environment to which the present invention is applied.
FIG. 2 is an exemplary view showing radio wave attenuation characteristics during terrestrial / air mobile communication.
3 is a block diagram showing the configuration of a transmission output control apparatus according to an embodiment of the present invention.
4 is an exemplary view showing an example of determining a correction value for an aircraft terminal according to an embodiment of the present invention.
5 is an operation flowchart showing an operation method of a transmission output control apparatus according to an embodiment of the present invention.

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

1 shows a terrestrial / air mobile communication environment to which the present invention is applied.

As illustrated in FIG. 1, the present invention is an environment in which one base station 100 must simultaneously service a terminal having very different propagation attenuation characteristics (eg, a ground terminal, an aircraft terminal), that is, ground mobile communication and public mobile communication. This coexistence environment is targeted.

In the case of a mobile communication service, due to an environment characteristic in which a base station must communicate with a plurality of terminals having different distances from each other, an uplink output control to appropriately increase / decrease the uplink transmission power of the terminal according to the distance from the base station (Uplink Power Control) function.

When this uplink output control function is described with reference to FIG. 1, the base station 100 uses the system information block type 2 (SIB2), which is one of channels for broadcasting system information of the base station, to set the transmission output control determined by the operator. It is transmitted by broadcasting.

At this time, in the information of the transmission output control setting, the strength of the downlink reference signal (CRS: Cell-specific Reference Signal) periodically transmitted by the base station 100, an uplink channel (eg, Physical Uplink Shared Channel (PUSCH), PUCCH) (Physical Uplink Control Channel)) Target receive signal level and propagation attenuation compensation settings are included.

Accordingly, a terminal (eg, 10, 20) receiving a transmission output control setting transmitted by broadcasting from the base station 100, the strength of the downlink CRS in the transmission output control setting and the downlink CRS actually received It is possible to estimate the amount of radio wave attenuation (Path Loss) according to the distance between itself and the base station 100 by comparing the intensity of.

And, the terminal (for example, 10, 20), the target reception signal level for each uplink channel in the transmission output control setting, the propagation attenuation compensation setting and the previously estimated propagation attenuation amount (PL), using the allocated from the base station 100 The transmission power can be determined for each sub-frame (1 ms) according to the number of uplink resource blocks (RBs) and adjusted.

As described above, in the case of a general uplink output control function, the base station continuously broadcasts the transmission output control setting determined by the operator, and the terminal receiving the transmission amount of radio wave attenuation between itself and the base station based on the transmission output control setting. This is a method of measuring and determining transmission power for each sub-frame (1 ms) according to the number of uplink resource blocks (RBs) allocated from the base station.

As an example, according to a general uplink output control function, for a PUSCH (Physical Uplink Shared Channel) used for data transmission, a transmission output may be determined through Equation 1 below.

Here, P _CMAX means the maximum transmission power that the terminal can use, and may have a value of 23 dBm for most bands and terminals.

P _PUCCH is a transmission output used for uplink control channel transmission, and an uplink data channel output (P _PUSCH ) cannot exceed P _CMAX -P _PUCCH .

M _PUSCH is the number of uplink RBs allocated to this sub-frame, and when RB is allocated twice, the transmission power should also be increased by 2 times (3dB), and P _{O_PUSCH} and α are the transmission power control broadcasted by the base station described above. It means the target received signal level and propagation attenuation compensation setting in the setting. For example, when the propagation attenuation compensation setting (α) is 1 (α = 1), when the amount of propagation attenuation with the base station measured by the terminal increases by 5 dB, it means that the uplink transmission power of the terminal also increases by 5 dB.

This general uplink output control function operates efficiently when one base station serves only terminals having similar propagation attenuation characteristics.

However, the general uplink output control function is efficient when one base station 100 needs to simultaneously service a terminal having very different propagation attenuation characteristics, such as the ground terminal 10 and the aircraft terminal 20, as shown in FIG. 1. There is a limitation that can not work as.

Specifically, due to obstacles such as buildings, automobiles, etc., it is difficult to secure a line of sight (LOS) path with the base station 100, that is, a general terminal located on the ground, that is, a ground terminal 10), and there is no obstacle, so the base station 100 and Air vehicle terminals (eg, drones, airplanes, etc.) located in the air having relatively easy LOS path acquisition will have very different mutual propagation attenuation characteristics.

For example, a representative COST231 Hata model (hereinafter referred to as Equation 2) among radio wave attenuation models in a terrestrial mobile communication environment and a free space radio wave attenuation model (hereinafter expressed as Equation 3) that can represent a public mobile communication environment. Are as follows respectively.

When using two radio wave attenuation models to compare the radio wave attenuation characteristics according to the distance in the case of terrestrial / air mobile communication in the 850 MHz band, as shown in FIG. 2.

However, since most base station antennas are mainly installed for terrestrial mobile communication and inclined toward the ground, in the case of public mobile communication, it is prepared for terrestrial mobile communication considering that the antenna gain is not the highest main beam direction. This is the result of inserting an additional 30 dB radio attenuation.

As can be seen in FIG. 2, at most of the distance between the base station and the terminal, the ATG PL of the aerial mobile communication is smaller than the ground PL of the ground mobile communication, and the attenuation between the ground mobile communication and the public mobile communication ( It can be seen that the difference) increases as the distance between the base stations and the terminals increases.

And, as can be seen in Figure 2, due to the difference in the propagation attenuation characteristics between the terrestrial / public mobile communication, the rate of increase in the amount of ATG PL of public mobile communication increases slowly compared to the amount of ground PL of ground mobile communication Can be confirmed.

Accordingly, when the ground terminal 10 and the vehicle terminal 20 connected to one base station 100 use the transmission power determined according to the general uplink output control function, the ground / air vehicle terminals 10 and 20 separated by the same distance Assuming from the perspective of interference to neighboring base stations, since the rate of increase in ATG PL of public mobile communication increases slowly compared to that of ground mobile communication, the uplink due to terrestrial terminal 10 Uplink interference due to the air vehicle terminal 20 is inevitably greater than interference.

As described above, considering that the rate of increase in radio wave attenuation (quantity) according to the distance is slower than that of the ground terminal 10 in the case of an aircraft terminal, if the common uplink output control function is commonly applied to the ground / air vehicle terminal, it is the same. A problem in which the performance of the terrestrial mobile communication service is relatively deteriorated may occur due to an aircraft terminal having greater air-to-ground (ATG) interference to an adjacent base station at a distance.

Accordingly, in the present invention, it is intended to propose a new method to suppress the strong ATG interference generated from the air vehicle terminal to maintain a balanced performance of the ground / air mobile communication service.

More specifically, in the present invention, it is intended to propose a transmission output control device that realizes a new method capable of suppressing strong ATG interference generated from an aircraft terminal.

First, a transmission output control apparatus according to a preferred embodiment of the present invention will be described in detail below with reference to FIG. 3.

As shown in FIG. 3, the transmission output control apparatus 200 according to an embodiment of the present invention may include a terminal identification unit 210 and a control unit 240.

In addition, the transmission output control apparatus 200 according to an embodiment of the present invention, in addition to the above-described configuration, a terminal (ground terminal, aircraft terminal) and / or a communication unit 250 which is an RF module in charge of a practical communication function with a base station ).

The entire or at least part of the configuration of the transmission output control device 200 may be implemented in the form of a hardware module or a software module, or a combination of a hardware module and a software module.

Here, the software module may be understood as, for example, an instruction executed by a processor that controls an operation in the transmission output control device 200, and these instructions may include a form mounted in the memory in the transmission output control device 200. Will have.

After all, the transmission output control apparatus 200 according to an embodiment of the present invention realizes a new method proposed by the present invention through the above-described configuration, that is, a new method capable of suppressing strong ATG interference generated from an aircraft terminal. , Hereinafter, each configuration in the transmission output control device 200 for realizing this will be described in more detail.

Prior to the detailed description, the transmission output control apparatus 200 of the present invention may be implemented to be the same as or included in the base station, in which case the communication unit 250 will communicate with the terminal (ground terminal, air vehicle terminal), and the terminal It may be implemented to be the same as or included in the terminal, in which case the communication unit 250 will communicate with the base station (service base station), and may be implemented as a separate device from the base station and the terminal, in which case the communication unit 250 is the terminal ( It will communicate with the ground terminal, the aircraft terminal) and the base station (service base station) of the terminal.

Hereinafter, for convenience of description, the transmission output control apparatus 200 of the present invention will be described as an embodiment implemented to be the same as the base station (100 in FIG. 1) or included in the base station (100 in FIG. 1).

The terminal identification unit 210 plays a role of checking whether the amount of radio wave attenuation corresponds to a first terminal category smaller than a specific threshold attenuation amount among a plurality of terminal categories having different radio wave attenuation characteristics, for a terminal accessing the service base station.

Here, the plurality of terminal categories having different propagation attenuation characteristics means a category for classifying the terminals according to the size of the amount of attenuation of the terminals based on the same distance.

As a typical example, the plurality of terminal categories is a category of a general terminal (hereinafter referred to as a ground terminal category) located on the ground where it is difficult to secure a line of sight (LOS) path with a base station due to an obstacle such as a building or a vehicle, and there is no obstacle. It can be divided into a category of terminals located in the air (hereinafter referred to as a vehicle terminal category) that is relatively easy to secure an LOS path with a base station compared to a ground terminal.

In the present invention, as the first terminal category in which the amount of radio wave attenuation among the plurality of terminal categories is smaller than a specific threshold attenuation amount, it will be described on the assumption that it is a vehicle terminal category.

In addition, the specific threshold attenuation amount at this time means a predetermined amount of radio wave attenuation that allows the terrestrial terminal and the air vehicle terminal to be classified based on the amount of radio wave attenuation.

That is, the terminal identification unit 210 confirms whether the terminal connected to the service base station, such as the base station 100, is a vehicle terminal corresponding to the first terminal category, that is, the vehicle terminal category.

Here, the method of confirming whether the vehicle is a terminal may be implemented in various ways.

According to an example, the terminal identification unit 210 is a service that is used in the first terminal category, that is, the aircraft terminal category, based on the QCI (QoS Class Identifier) granted according to the service type of the terminal. If it is a specific QCI defined to be assigned to, the terminal to be accessed this time can be identified as an aircraft terminal.

To this end, the process of defining / setting QCI received from the Evolved Packet Core (EPC) according to the service type of the terminal when connecting to the network is different from the general call for services used in the category of the vehicle terminal (eg, QCI 7, etc.) This will be preceded.

As a result of checking by the terminal identification unit 210, the control unit 240 outputs an uplink transmission so that the intensity of uplink interference to a neighboring base station with respect to the neighboring base station is reduced when the terminal accessed this time is a vehicle terminal corresponding to the vehicle terminal category. Perform control.

That is, the control unit 240 is intended to suppress the ATG interference by separately performing uplink transmission power control for the uplink interference strength to the adjacent base station to be reduced for the aircraft terminal.

In more detail, the controller 240 estimates the amount of downlink propagation attenuation between the terminal and the service base station 100 for the air vehicle terminal, and uses the estimated amount of downlink propagation attenuation to uplink interference strength to an adjacent base station. As a method of controlling the uplink transmission power of the terminal so that is small, the uplink transmission power control may be performed.

To this end, the control unit 240 may include an estimation unit 220 and a transmission output control unit 230.

The estimation unit 220, if the terminal to be accessed this time as a result of the confirmation of the terminal identification unit 210 is an air vehicle terminal (hereinafter, referred to as the terminal 20), the downlink propagation between the terminal 20 and the service base station 100 Estimate the path loss.

Here, a method of estimating the amount of downlink propagation (PL) between the terminal 20 and the service base station 100 may be implemented in various ways.

When an example is described, a downlink propagation attenuation (PL) may be estimated by using downlink channel quality information (CQI) reported to a service base station by a terminal connected to a network every set period.

Specifically, the estimation unit 220, the terminal 20 and the service base station 100, based on the downlink channel quality information (CQI: Channel Quality Information) that the terminal 20 reports to the service base station 100 ) Can be estimated by calculating the downlink propagation attenuation (PL).

As mentioned in the description of the information included in the transmission output control setting for transmitting the broadcasting, the service base station 100 determines the strength of the downlink CRS (RS _Level ) that the terminal 20 uses as a reference when estimating the amount of radio wave attenuation. Know.

Further, the room temperature (T = 300K) thermal noise value (Thermal_Noise) in the 15 kHz bandwidth to which the downlink reference signal (CRS) is transmitted can be regarded as -132 dBm by the Johnson-Nyquist noise equation.

Therefore, if the downlink signal-to-noise ratio (SNR) of the UE is known, the downlink propagation attenuation (PL) of the UE can be estimated by using Equation 4 below.

[Equation 4]

Accordingly, the estimator 220 must first find out the downlink signal-to-noise ratio (SNR) of the terminal 20 in order to calculate the downlink propagation attenuation (PL) between the terminal 20 and the service base station 100. .

To this end, the estimation unit 220, based on the downlink channel quality information (CQI) that the terminal 20 reports to the service base station 100 and the downlink modulation technique used for the terminal 20, the downlink Estimate the signal-to-noise ratio (SNR).

Specifically, in CQI, two different tables are defined as standard according to whether the downlink modulation technique uses 256QAM.

In addition, CQI, by definition, is the maximum modulation (modulation) and coding rate (code rate) in which a transmission unit (Transport Block) is likely to cause an error (Error) within 10% of the terminal receiving end when transmitting from the base station. Is meant.

Therefore, CQI is closely related to downlink signal-to-noise ratio (SNR) at the time, and it is easy to obtain mapping data (table) between CQI and downlink signal-to-noise ratio (SNR) through theoretical simulation or actual field measurement. can do.

Accordingly, if the estimation unit 220 estimates the downlink signal-to-noise ratio (SNR) based on mapping data (table) between the CQI and the downlink signal-to-noise ratio (SNR), the estimated downlink signal-to-noise ratio (DL _SNR ) and The downlink propagation attenuation (PL) between the terminal 20 and the service base station 100 may be calculated through Equation 4 above using the strength of the downlink CRS (RS _Level ) and the thermal noise value (Thermal_Noise).

Table 1 below, when the downlink modulation scheme uses 256QAM, utilizes downlink signal-to-noise ratio (SNR) data required for each CQI obtained, and the terminal through Equation 4 above. This report shows an example of estimating the downlink propagation attenuation (PL) for each CQI.

CQI index modulation code rate x 1024 DL SINR
(dB) RS Level
(dBm) Pathloss (dB) 0 out of range One QPSK 78 -8.18 10.00 150.42 2 QPSK 193 -4.37 10.00 146.61 3 QPSK 449 -1.84 10.00 144.08 4 16QAM 378 0.24 10.00 142.00 5 16QAM 490 4.32 10.00 137.92 6 16QAM 616 4.35 10.00 137.89 7 64QAM 466 6.53 10.00 135.71 8 64QAM 567 9.79 10.00 132.45 9 64QAM 666 11.78 10.00 130.46 10 64QAM 772 17.09 10.00 125.15 11 64QAM 873 19.06 10.00 123.18 12 256QAM 711 19.24 10.00 123.00 13 256QAM 797 21.18 10.00 121.06 14 256QAM 885 26.51 10.00 115.73 15 256QAM 948 28.64 10.00 113.60

Of course, in addition to this method, the estimation unit 220, the terminal 20, the downlink propagation attenuation amount (PL) directly estimated based on the transmission output control settings (especially, the strength of the downlink CRS) from the service base station 100 ).

The transmission output control unit 230 controls the uplink transmission power of the terminal 20 so that the intensity of uplink interference to an adjacent base station is reduced by using the downlink propagation attenuation (PL) estimated by the estimation unit 220. .

Here, according to the downlink propagation attenuation (PL) estimated for the air vehicle terminal, how much to increase / decrease the uplink transmission power of the terminal 20 can be designed according to an optimization parameter of only a communication operator.

According to an embodiment of the present invention, when a terrestrial terminal is located at a boundary of a base station where interference problems are most prominent, the distance between adjacent base stations is closest, so in this case, the uplink interference strength of the terrestrial terminal affecting the adjacent base stations Given that it will be the largest, it is possible to control the uplink transmission power so that the uplink interference to the adjacent base station of the air vehicle terminal is lowered to the level of the uplink interference to the adjacent base station at the same distance from the service base station.

Specifically, the transmission output control unit 230 determines a correction value for controlling the uplink transmission output of the terminal 20 by using the downlink propagation attenuation PL estimated by the estimation unit 220.

4 shows an example of determining a correction value for a vehicle terminal (eg, terminal 20).

In consideration of the fact that the LOS path is always secured because there is no obstacle between the service base station 100 and the terminal 20, the vehicle terminal, that is, the terminal 20, the transmission output control unit 230 is estimated by the estimation unit 220 downward Based on the link propagation attenuation amount (PL) and the downlink signal strength transmitted by the service base station 100, that is, the strength of the downlink CRS, through the free space propagation attenuation model as in Equation 3 above, the terminal 20 and the service base station The distance between (100) can be inverted.

Then, the transmission output control unit 230, based on a predefined radio wave attenuation model, that is, a mobile communication radio wave attenuation model of a general terrestrial mobile communication environment such as Equation 2, the distance obtained by inversely calculating the service base station 100 and the tactics ( It is possible to estimate a downlink propagation attenuation amount for a specific terminal having a distance between the terminal 20 and the service base station 100).

Here, the specific terminal means a second terminal category in which the amount of radio wave attenuation among a plurality of terminal categories is greater than a specific threshold attenuation amount, and according to the above-described example, means a terminal (hereinafter, a terrestrial terminal) corresponding to the terrestrial terminal category.

That is, the transmission output control unit 230, on the basis of the service base station 100, assumes a terrestrial terminal at the same distance as the terminal 20 which is an air vehicle terminal, and the amount of downlink radio wave attenuation for the terrestrial terminal (Ground PL) Is to estimate.

The transmission output control unit 230 compensates for the difference between the downlink propagation attenuation amount PL estimated by the estimating unit 220 and the estimated downlink propagation attenuation amount (Ground PL) by assuming a terrestrial terminal having the same distance. It can be determined as a correction value for controlling the uplink transmission power of 20).

For example, as illustrated in FIG. 4, the amount of downlink propagation (PL_air) of the terminal 20 (aircraft terminal) estimated by the estimator 220 is 115 dB, and the amount of downlink propagation estimated by assuming a ground terminal having the same distance. Assuming that (PL_Ground) is 119 dB, the difference between these two downlink propagation attenuations (PL_air) and downlink propagation attenuation (PL_Ground) can be determined as a correction value for controlling the uplink transmission power of the UE 20. have.

In addition, the transmission output control unit 230 provides a correction value (for example, -4 dB) determined for the terminal 20 to the terminal 20, so that the terminal 20 is broadcast from the service base station 100 and broadcast (Broadcasting) is transmitted. It is controlled to reflect the correction value to the predetermined uplink transmission output based on the transmission output control setting.

As described above with respect to the general uplink output control function, when the service base station 100 receives the transmission output control setting continuously broadcasting (Broadcasting), the terminal 20 itself, based on the received transmission output control setting The amount of propagation attenuation between the service base station 100 and the service base station 100 is measured, and transmission power is determined for each sub-frame (1 ms) according to the number of uplink RBs allocated from the service base station 100.

At this time, the terminal 20 is a correction value received from the transmission power control apparatus 200 of the present invention, for a predetermined uplink transmission output based on the transmission output control setting transmitted from the service base station 100 (eg, -4dB) Can reflect.

In this case, the terminal 20, which is an aircraft terminal, uplinks the terminal 20 by reflecting a correction value (eg, -4dB) to the transmission output determined based on the transmission output control setting according to the general uplink output control function. The uplink transmission power of the terminal 20 may be controlled such that the uplink interference of the transmission output to the neighboring base station is lowered to the level of uplink interference of the ground terminal having the same distance to the neighboring base station with respect to the service base station 100.

At this time, according to an example, the transmission output control unit 230, using a TPC (Transmit Power Control) Command Field in the DCI (Downlink Control Information), which is a message used to control the transmission output from the base station to individual terminals when necessary, the correction value (Eg -4dB) may be provided / applied to the terminal 20.

If the transmission output of the terminal 20 is not controlled to a desired level by providing (transmitting) a correction value using a single TPC command, the transmission output control unit 230 may transmit multiple times until the desired level is controlled. .

As described above, according to the transmission output control apparatus of the present invention, in consideration of the propagation attenuation characteristics of the air vehicle terminal in which the rate of increase of the radio wave attenuation (quantity) according to the distance increases slowly compared to the ground terminal, it occurs from the air vehicle terminal. We are realizing a new way to suppress strong ATG (Air to Ground) interference.

For this reason, according to the present invention, when a common uplink output control function is commonly applied to a ground / aircraft terminal, ground mobile communication is caused by an aircraft terminal having greater air to ground (ATG) interference to an adjacent base station at the same distance. Since it is possible to solve the problem that the performance of the service is relatively deteriorated, the effect of maintaining the performance of the ground / air mobile communication service in a balanced manner is derived.

Hereinafter, a process of implementing the ATG interference suppression scheme proposed in the present invention will be described in detail with reference to FIG. 5.

For convenience of explanation, it will be described by referring to the operation method of the transmission output device of the present invention, the reference number of the transmission output device is the same as shown in FIG. 3, and the transmission output control device 200 is a base station (FIG. 1 100) and the embodiment implemented to be included in the base station (100 in FIG. 1) will be described.

First, according to the operation method of the transmission output device of the present invention, the transmission output device (200, base station 100), using the SIB2, one of the channels for broadcasting the system information of the base station, the predetermined transmission output control settings Broadcast (Broadcasting) and transmits (S100).

At this time, the information of the transmission output control setting, the strength of the downlink reference signal (CRS) periodically transmitted by the base station 100, the target reception signal level for each uplink channel (eg PUSCH, PUCCH), and the propagation attenuation compensation setting Included.

On the other hand, according to the operation method of the transmission output device of the present invention, the transmission output device (200, the base station 100), when the terminal (eg, the terminal 20) connected to the base station 100 is recognized (S110), With respect to the terminal 20, it is determined whether the vehicle terminal corresponds to the vehicle terminal category (S120).

According to an example, the transmission output device 200 (base station 100) is based on the QCI (QoS Class Identifier) granted according to the service type of the terminal, the QCI of the terminal 20 to be accessed this time is used by the aircraft terminal If it is a specific QCI defined to be provided to a service, the terminal 20 to be accessed this time can be identified as an aircraft terminal.

According to the operation method of the transmission output device of the present invention, the transmission output device (200, the base station 100), the terminal 20 to be accessed this time as a result of the check in step S120 is a flying terminal (S120 Yes), the terminal 20 ), The uplink transmission power control is performed so that the uplink interference intensity on the adjacent base station is reduced (S130 to S150).

More specifically, the transmission output device 200 (base station 100) estimates the amount of downlink propagation attenuation between the terminal 20 and the service base station 100 with respect to the terminal 20 identified as the air vehicle terminal ( S130).

For example, the transmission output device 200, the base station 100, as mentioned in the description of the information included in the transmission output control setting previously broadcast transmission, the terminal 20 is used as a reference when estimating the amount of radio wave attenuation The strength of the downlink CRS (RS _Level ) is known.

Further, the room temperature (T = 300K) thermal noise value (Thermal_Noise) in the 15 kHz bandwidth to which the downlink reference signal (CRS) is transmitted can be regarded as -132 dBm by the Johnson-Nyquist noise equation.

Therefore, if the downlink signal-to-noise ratio (SNR) of the UE 20 is known, the downlink propagation attenuation (PL) of the UE 20 can be estimated using Equation 4 above. have.

Meanwhile, in the CQI, two different tables are defined as a standard according to whether the downlink modulation technique uses 256QAM.

And, the downlink channel quality information that the terminal connected to the network reports to the service base station every set period, that is, CQI, by definition, when transmitted from the base station, the transport unit (Transport Block) error with a probability of less than 10% at the terminal receiving end It means the maximum modulation and code rate at which (Error) is likely to occur.

Therefore, CQI is closely related to downlink signal-to-noise ratio (SNR) at the time, and it is easy to obtain mapping data (table) between CQI and downlink signal-to-noise ratio (SNR) through theoretical simulation or actual field measurement. can do.

Accordingly, if the transmission output device 200, the base station 100 estimates a downlink signal-to-noise ratio (SNR) based on mapping data (table) between CQI and downlink signal-to-noise ratio (SNR), the estimated downlink signal-to- Downlink propagation attenuation (PL) between the terminal 20 and the service base station 100 through Equation 4 above using the noise ratio (DL _SNR ), the strength of the downlink CRS (RS _Level ), and the thermal noise value (Thermal_Noise) Can be calculated (S130).

According to the operation method of the transmission output device of the present invention, the transmission output device 200 (base station 100), using the downlink propagation attenuation (PL) estimated in step S130, the correction value, that is, the uplink of the terminal 20 A correction value for controlling the transmission output is determined (S140).

Specifically, considering that there is no obstacle between the vehicle terminal, that is, the terminal 20 and the service base station 100, so that the LOS path is always secured, the transmission output device 200 and the base station 100 estimate downward in step S130. Based on the intensity of the downlink CRS transmitted by the link propagation attenuation (PL) and the service base station 100, the distance between the terminal 20 and the service base station 100 through a free space propagation attenuation model as in Equation 3 above Can be inverted / estimated

Then, the transmission output device 200, the base station 100, based on the predefined radio wave attenuation model, that is, the mobile communication radio wave attenuation model of a general terrestrial mobile communication environment such as Equation 2, the service base station 100 and the tactics It is possible to estimate the downlink propagation attenuation amount (Ground PL) for a terrestrial terminal having a distance (the distance between the terminal 20 and the service base station 100) obtained by inversion.

Accordingly, the transmission output device 200, the base station 100, the difference between the downlink propagation attenuation (PL) estimated in step S130 and the estimated downlink propagation attenuation (Ground PL) on the assumption of a terrestrial terminal at the same distance, A correction value, that is, a correction value for controlling the uplink transmission output of the terminal 20 may be determined (S140).

For example, as illustrated in FIG. 4, the downlink propagation attenuation amount (PL_air) of the terminal 20 (aircraft terminal) estimated in step S130 is 115 dB, and the downlink propagation attenuation amount (PL_Ground) estimated by assuming a ground terminal having the same distance. Assuming that is 119 dB, the difference between these two downlink propagation attenuation (PL_air) and downlink propagation attenuation (PL_Ground) -4dB may be determined as a correction value for controlling the uplink transmission power of the terminal 20.

In addition, according to the operation method of the transmission output device of the present invention, the transmission output device 200 (base station 100) provides a correction value (for example, -4 dB) determined for the terminal 20 to the terminal 20 (S150) ), The terminal 20 is controlled to reflect the correction value to the predetermined uplink transmission output based on the transmission output control setting transmitted from the service base station 100 (Broadcasting) (S160).

At this time, according to an example, the transmission output device 200, the base station 100, the TPC (Transmit Power Control) Command Field in the DCI (Downlink Control Information) that is a message used to control the transmission output from the base station to an individual terminal when necessary. Using, it is possible to provide / apply a correction value (eg, -4dB) to the terminal 20 (S150).

As described above with respect to the general uplink output control function, when the service base station 100 receives the transmission output control setting continuously broadcasting, the terminal 20 bases itself and the service base station on the basis of the received transmission output control setting. The amount of propagation attenuation between (100) is measured, and transmission power is determined for each sub-frame (1 ms) according to the number of uplink RBs allocated from the service base station 100.

At this time, the terminal 20 is a correction value received from the transmission power control device 200 of the present invention, for a predetermined uplink transmission output based on the transmission output control setting transmitted from the service base station 100 (eg, -4dB) It may reflect (S160).

In this case, the terminal 20, which is an aircraft terminal, reflects a correction value (for example, -4 dB) to the transmission output determined based on the transmission output control setting according to the general uplink output control function (S160), and the terminal 20 The uplink transmission power of the terminal 20 may be controlled such that the uplink interference of the uplink transmission power of the neighboring base station is lowered to the level of the uplink interference of the ground terminal having the same distance to the neighboring base station based on the service base station 100. have.

On the other hand, according to the operation method of the transmission output device of the present invention, the transmission output device (200, the base station 100), the result of the check in step S120, if the terminal to be accessed this time is not an air vehicle terminal, that is, a ground terminal (S120 No) ), The ATG interference suppression method proposed in the present invention will not be applied.

In this case, the terrestrial terminal (eg, the terminal 10) will use the transmission power determined based on the transmission output control setting according to the conventional uplink output control function as in the conventional case (S165).

As described above, according to the operation method of the transmission power control device according to the present invention, in the case of an aircraft terminal, considering the propagation attenuation characteristic of the increase in the rate of propagation attenuation (amount) according to the distance, compared to the ground terminal, the aircraft terminal By realizing a new method of suppressing strong air-to-ground (ATG) interference generated from, the effect of maintaining the balance of the performance of the ground / air mobile communication service is derived.

The operation method of the transmission output control apparatus according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and may be recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. Includes hardware devices specifically configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler. The hardware device described above may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

The present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above-described embodiments, and the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims below. Anyone with ordinary knowledge in the technical idea of the present invention extends to the extent that various modifications or modifications are possible.

According to the operation method of the transmission output control device and the transmission output control device of the present invention, by suppressing strong ATG (Air to Ground) interference generated from the aircraft terminal, it is possible to maintain the balance of the ground / air mobile communication service performance, As it surpasses the limitations of the existing technology, it is not only the use of the related technology, but also the possibility of commercially available or sales of the applied device, as well as the degree that it can be carried out in a realistic manner, making it an industrially applicable invention.

200: transmission output control device
210: terminal identification unit 220: estimation unit
230: transmission output control unit 240: control unit

Claims (12)

A terminal identification unit for confirming whether the amount of radio wave attenuation corresponds to a first terminal category smaller than a specific threshold attenuation amount among a plurality of terminal categories having different radio wave attenuation characteristics for a terminal accessing the service base station; And
If the terminal corresponds to the small first terminal category, a transmission output control apparatus comprising a control unit for performing uplink transmission output control for the terminal to the uplink interference strength to the adjacent base station is small. According to claim 1,
The control unit,
If the terminal corresponds to the small first terminal category, an estimator for estimating the amount of downlink propagation between the terminal and the service base station,
And a transmission output control unit for controlling the uplink transmission power of the terminal so that the intensity of uplink interference to an adjacent base station is reduced by using the estimated downlink propagation attenuation amount. According to claim 1,
The terminal identification unit,
On the basis of the QCI (QoS Class Identifier) granted according to the service type of the terminal, if the QCI of the terminal is a specific QCI defined to be assigned to a service used in the first terminal category, the first terminal category is checked. Transmission output control device. According to claim 2,
The transmission output control unit,
Providing a correction value determined using the estimated downlink propagation attenuation to the terminal,
A transmission output control device characterized in that the terminal controls to reflect the correction value in a predetermined uplink transmission output based on a transmission output control setting transmitted from a service base station. The method of claim 4,
The transmission output control unit,
Using the estimated distance between the terminal and the service base station estimated based on the estimated downlink radio wave attenuation amount and the downlink signal strength transmitted by the service base station, the service base station and the distance based on a predefined radio wave attenuation model. Estimated downlink propagation attenuation for a specific terminal having,
The difference between the estimated downlink propagation attenuation amount and the estimated downlink propagation attenuation for a specific terminal is determined as the correction value,
The specific terminal,
A transmission output control device, characterized in that the radio wave attenuation amount among the plurality of terminal categories is a terminal corresponding to a second terminal category having a greater than a specific threshold attenuation amount. According to claim 1,
The estimation unit,
A transmission output control apparatus characterized by calculating and estimating the amount of downlink propagation between the terminal and the service base station based on the downlink channel quality information (CQI) reported by the terminal to the service base station. The method of claim 6,
The estimation unit,
A downlink signal-to-noise ratio (SNR) estimated based on the downlink channel quality information (CQI) and a downlink modulation technique used for the terminal, and a downlink signal transmitted by the service base station Using century,
Transmission output control device characterized in that for calculating the amount of downlink radio wave attenuation for the terminal. A terminal identification step of confirming, for a terminal accessing the service base station, whether the amount of radio wave attenuation corresponds to a first terminal category smaller than a specific threshold attenuation among a plurality of terminal categories having different propagation attenuation characteristics; And
A propagation attenuation estimating step of estimating a downlink propagation attenuation amount between the terminal and the service base station when the terminal corresponds to a small first terminal category; And
And a transmission power control step of controlling the uplink transmission power of the terminal so that the intensity of uplink interference to an adjacent base station is reduced by using the estimated downlink propagation attenuation amount. . The method of claim 8,
The transmission output control step,
Providing a correction value determined using the estimated downlink propagation attenuation to the terminal,
A method for operating a transmission output control apparatus, characterized in that the terminal controls to reflect the correction value in a predetermined uplink transmission output based on a transmission output control setting transmitted from a service base station. The method of claim 9,
The transmission output control step,
Using the estimated distance between the terminal and the service base station estimated based on the estimated downlink radio wave attenuation amount and the downlink signal strength transmitted by the service base station, the service base station and the distance based on a predefined radio wave attenuation model. Estimated downlink propagation attenuation for a specific terminal having,
The difference between the estimated downlink propagation attenuation amount and the estimated downlink propagation attenuation for a specific terminal is determined as the correction value,
The specific terminal,
A method of operating a transmission output control apparatus, characterized in that the radio wave attenuation amount among the plurality of terminal categories is a terminal corresponding to a second terminal category having a greater than a specific threshold attenuation amount. The method of claim 8,
The radio wave attenuation estimating step,
Based on downlink channel quality information (CQI) reported by the terminal to the service base station, an operation method of the transmission output control apparatus characterized by calculating and estimating a downlink propagation amount between the terminal and the service base station . The method of claim 11,
The radio wave attenuation estimating step,
A downlink signal-to-noise ratio (SNR) estimated based on the downlink channel quality information (CQI) and a downlink modulation technique used for the terminal, and a downlink signal transmitted by the service base station Using century,
Method of operation of a transmission output control device characterized in that for calculating the amount of attenuation of downlink radio waves for the terminal.

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