KR102165802B1 - Transmission power control device and control method thereof - Google Patents

Abstract

The present invention discloses a technology for realizing a new method for maintaining a balanced ground/air mobile communication service performance by suppressing strong ATG (Air to Ground) interference generated from an aircraft terminal in consideration of the difference in radio wave attenuation characteristics. .

Description

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

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

In the case of a mobile communication service, the uplink output control that increases/decreases the uplink transmission power of the terminal appropriately according to the distance from the base station due to the environmental characteristics in which the base station must communicate with a plurality of terminals with different distances from it. Power Control) function.

This uplink output control is one of functions that have a great influence on service quality in mobile communication services.

To explain the uplink power control function, the base station continuously broadcasts and transmits the transmission power control setting determined by the operator.

At this time, the information on the transmission power control setting includes the strength of a downlink reference signal (CRS) periodically transmitted by the base station, a target reception signal level for each uplink channel, and a radio wave attenuation compensation setting.

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

Such a general uplink output control function operates efficiently when one base station serves only terminals having similar radio wave attenuation characteristics.

Meanwhile, a general uplink output control function has a limitation in that it cannot operate efficiently when one base station must simultaneously service terminals (eg, ground terminals, aircraft terminals) having very different radio wave attenuation characteristics.

Specifically, it is difficult to secure a LOS (Line of Sight) path to the base station due to obstacles such as buildings and cars, and it is relatively difficult to secure a LOS path to the base station because there is no obstacle. Vehicle terminals (e.g. drones, airplanes, etc.) located in the air will have very different radio wave attenuation characteristics.

Due to this difference in radio wave attenuation characteristics, in the case of the aircraft terminal, the increase rate of the radio wave attenuation (amount) according to the distance increases more slowly than that of the ground terminal, and for this reason, the ground terminal and the aircraft terminal determine according to the general uplink output control function. In the case of using the transmission power, from the viewpoint of interference to neighboring base stations assuming a ground/aircraft terminal at the same distance, the uplink interference caused by the aircraft terminal is inevitably greater than the uplink interference caused by the ground terminal.

Therefore, considering that the increase rate of radio wave attenuation (amount) according to the distance increases slowly compared to the ground terminal in the case of an aircraft terminal, if the general uplink output control function is commonly applied to the ground/aircraft terminal, it is adjacent at the same distance. There may be a problem in that the performance of the ground mobile communication service is relatively degraded due to the aircraft terminal having a greater interference to the base station, that is, air to ground (ATG) interference.

Accordingly, in the present invention, it is intended to propose a new method capable of maintaining a balanced ground/air mobile communication service performance by suppressing strong air to ground (ATG) interference generated from an aircraft terminal.

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

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

Specifically, when the terminal corresponds to a small first terminal category, the controller uses an estimating unit for estimating a downlink propagation attenuation between the terminal and the serving base station, and the estimated downlink propagation attenuation. It may include a transmission power control unit for controlling the uplink transmission power of the terminal to reduce the intensity of uplink interference to the base station.

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

Specifically, the transmission power control unit provides a correction value determined using the estimated downlink propagation attenuation to the terminal, so that the terminal is configured based on a transmission power control setting transmitted by broadcasting from a service base station. It can be controlled to reflect the correction value to the determined uplink transmission power.

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

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

Specifically, the estimator includes 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 the service The downlink propagation attenuation amount for the terminal can be calculated by using the downlink signal strength transmitted by the base station.

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

Specifically, in the transmission power control step, a correction value determined using the estimated downlink propagation attenuation amount is provided to the terminal, and the terminal is based on a transmission power control setting transmitted by broadcasting from a serving base station. It can be controlled to reflect the correction value to a predetermined uplink transmission power.

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

Specifically, the propagation attenuation amount estimating step may be estimated by calculating a downlink propagation attenuation amount between the terminal and the serving base station based on downlink channel quality information (CQI) reported by the terminal to the serving base station. have.

Specifically, the step of estimating the amount of propagation attenuation includes 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 , Using the downlink signal strength transmitted by the serving base station, a downlink propagation attenuation amount for the terminal may be calculated.

Accordingly, according to the operating method of the transmission power control device and the transmission power control device of the present invention, by realizing a new method to suppress strong ATG (Air to Ground) interference generated from the aircraft terminal, the ground/air mobile communication service performance is improved. It derives an effect that can be kept in balance.

1 is an exemplary diagram showing a ground/air mobile communication environment to which the present invention is applied.
2 is an exemplary diagram showing radio wave attenuation characteristics during land/air mobile communication.
3 is a block diagram showing the configuration of a transmission power 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 a method of operating a transmission power 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 ground/air mobile communication environment to which the present invention is applied.

In the present invention, as shown in FIG. 1, an environment in which one base station 100 must simultaneously service terminals (eg, ground terminals, aircraft terminals) having very different radio wave attenuation characteristics, that is, ground mobile communication and aerial mobile communication. It targets this coexisting environment.

In the case of a mobile communication service, the uplink output control that increases/decreases the uplink transmission power of the terminal appropriately according to the distance from the base station due to the environmental characteristics in which the base station must communicate with a plurality of terminals with different distances from it. Power Control) function.

When this uplink output control function is described with reference to FIG. 1, the base station 100 uses SIB2 (System Information Blocktype 2), which is one of the channels for broadcasting system information of the base station, and sets the transmission power control set by the operator. Broadcast and transmit.

At this time, the information of the transmission power control setting includes the strength of a downlink reference signal (CRS) periodically transmitted by the base station 100, an uplink channel (e.g., Physical Uplink Shared Channel (PUSCH), PUCCH). (Physical Uplink Control Channel)) Each target received signal level and radio wave attenuation compensation setting are included.

Accordingly, the terminal (e.g., 10, 20) receiving the transmission power control setting transmitted by broadcasting from the base station 100, the strength of the downlink CRS in the transmission power control setting and the downlink CRS actually received by itself It is possible to estimate the path loss according to the distance between itself and the base station 100 by comparing the strength of.

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

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

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

Here, P _CMAX denotes 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 power used for uplink control channel transmission, and the 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, indicating that if RBs are allocated twice, the transmission power should also increase by 2 times (3dB), and P _{O_PUSCH} and α control the transmission power broadcast from the base station described above. It means the target reception signal level and radio wave attenuation compensation setting in the setting. For example, when the radio wave attenuation compensation setting (α) is 1 (α = 1), when the radio wave attenuation amount measured by the terminal with the base station increases by 5 dB, it means that the uplink transmission power of the terminal is also increased by 5 dB.

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

However, the general uplink output control function is effective when one base station 100 needs to simultaneously service terminals with very different radio attenuation characteristics, such as a ground terminal 10 and an aircraft terminal 20, as shown in FIG. There is a limitation in that it cannot be operated with.

Specifically, a general terminal located on the ground that is difficult to secure a line of sight (LOS) path with the base station 100 due to obstacles such as buildings and automobiles, that is, a ground terminal 10), and the base station 100 because there is no obstacle. Vehicle terminals (20, for example, drones, airplanes, etc.) located in the air where it is relatively easy to secure the LOS path of the vehicle will have very different radio wave attenuation characteristics.

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

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

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

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

And, as can be seen from Figure 2, due to the difference in radio wave attenuation characteristics between land/air mobile communication, the increase rate of the radio wave attenuation amount (ATG PL) of the aerial mobile communication slowly increases compared to the radio wave attenuation amount (Ground PL) of the land mobile communication I can confirm.

Therefore, when the ground terminal 10 and the aircraft 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 From the viewpoint of interference to neighboring base stations, assuming that the increase rate of the radio wave attenuation (ATG PL) of the public mobile communication increases slowly compared to the ground PL of the terrestrial mobile communication, the uplink due to the ground terminal 10 The uplink interference due to the vehicle terminal 20 is inevitably greater than the interference.

As described above, in the case of the aircraft terminal, considering that the increase rate of the radio wave attenuation (amount) according to the distance increases slowly compared to the ground terminal 10, if the general uplink output control function is commonly applied to the ground/aircraft terminal, the same A problem in that the performance of a ground mobile communication service is relatively degraded may occur due to an aircraft terminal having a 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 capable of maintaining a balanced ground/air mobile communication service performance by suppressing strong ATG interference generated from an aircraft terminal.

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

First, hereinafter, a transmission power control apparatus according to a preferred embodiment of the present invention will be described in detail 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.

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

All or at least a part of the configuration of the transmission power control apparatus 200 may be implemented in the form of a hardware module or a software module, or may be implemented in a form in which a hardware module and a software module are combined.

Here, the software module may be understood as, for example, a command executed by a processor that controls an operation in the transmission output control device 200, and such a command is a form mounted in a memory in the transmission output control device 200. You will be able to have it.

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

Prior to the detailed description, the transmission power control apparatus 200 of the present invention may be implemented to be the same as the base station or included in the base station, and in this case, the communication unit 250 will communicate with a terminal (ground terminal, aircraft terminal), and the terminal The same as or may be implemented to be included in the terminal. In this 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 this case, the communication unit 250 is the terminal ( It will communicate with ground terminals, aircraft terminals) and their base stations (service base stations).

Hereinafter, for convenience of description, the transmission power control apparatus 200 of the present invention will be described with reference to 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 is responsible for checking whether the radio wave attenuation amount 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 with respect to a terminal accessing the service base station.

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

As a representative example, multiple terminal categories are categories of general terminals located on the ground (hereinafter referred to as ground terminal categories) where it is difficult to secure a line of sight (LOS) route with the base station due to obstacles such as buildings and vehicles, and there are no obstacles. It can be classified into a category of a terminal located in the air (hereinafter, a vehicle terminal category), which is relatively easy to secure an LOS path with a base station compared to a ground terminal.

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

In addition, the specific critical attenuation amount at this time means a predetermined amount of radio wave attenuation that allows the ground terminal and the aircraft terminal to be classified based on the radio wave attenuation amount.

That is, the terminal identification unit 210 is to check whether the terminal is a first terminal category, that is, a vehicle terminal corresponding to the vehicle terminal category with respect to the terminal connected to the service base station, for example, the base station 100.

Here, a method of checking whether the vehicle is a terminal may be variously implemented.

According to an example, the terminal identification unit 210, based on the QCI (QoS Class Identifier) assigned according to the service type of the terminal, the QCI of the terminal to be accessed is a service used in the first terminal category, that is, the aircraft terminal category. 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 the QCI that is given from Evolved Packet Core (EPC) according to the service type of the terminal when connecting to the network differently from the general call for the service used in the aircraft terminal category (e.g., QCI 7) Will be preceded.

The control unit 240, when the terminal to be accessed is an aircraft terminal corresponding to the aircraft terminal category as a result of the confirmation by the terminal identification unit 210, the uplink transmission power to reduce the intensity of uplink interference to the adjacent base station with respect to the terminal Perform control.

That is, the control unit 240 is to suppress the ATG interference by separately performing uplink transmission power control for reducing the intensity of uplink interference to neighboring base stations for the vehicle terminal.

More specifically, the control unit 240 estimates the amount of downlink propagation attenuation between the terminal and the service base station 100 for the vehicle terminal, and uses the estimated downlink propagation attenuation to the uplink interference strength to the adjacent base station. In a method of controlling the uplink transmission power of the terminal so that is small, uplink transmission power control can be performed.

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

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

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

To describe an example, a downlink propagation attenuation amount (PL) can be estimated by using downlink channel quality information (CQI) reported to a serving base station every set period by a terminal connected to the network.

Specifically, the estimating unit 220 is based on the downlink channel quality information (CQI) reported by the terminal 20 to the service base station 100, the terminal 20 and the service base station 100 ) Can be estimated by calculating the downlink propagation attenuation (PL).

The service base station 100, the terminal 20 century (RS _Level) of the downlink CRS that is used as the reference when estimating propagation attenuation, as referred to in which information described include a transmit power control settings that are transmitted prior Broadcasting Know.

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

Therefore, if the downlink signal-to-noise ratio (SNR) of the terminal can be known, the downlink propagation attenuation (PL) of the terminal at the time point can be estimated using Equation 4 below.

[Equation 4]

Accordingly, the estimating unit 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 serving base station 100. .

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

Specifically, for CQI, two different tables are standardly defined according to whether or not the downlink modulation scheme uses 256QAM.

And, CQI is, by definition, the maximum modulation and code rate at which an error is expected to occur with a probability within 10% of the terminal receiving end of the transport block when transmitted from the base station. Means.

Therefore, CQI is closely related to the downlink signal-to-noise ratio (SNR) at the time point, and mapping data (table) between CQI and downlink signal-to-noise ratio (SNR) is easily secured 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 the 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 serving 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 shows that when the downlink modulation method uses 256QAM, the UE through Equation 4 above, using downlink signal-to-noise ratio (SNR) data required for each secured CQI. An example of estimating the amount of downlink propagation attenuation (PL) at the time point for each reported CQI is shown.

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 estimating unit 220 directly estimates the downlink propagation attenuation (PL) based on the transmission power control setting (in particular, the strength of the downlink CRS) from the serving base station 100 by the terminal 20. It would also be possible to check in a way to obtain)

The transmission power control unit 230 controls the uplink transmission power of the terminal 20 so that the intensity of uplink interference to the neighboring base station decreases by using the downlink propagation attenuation (PL) estimated by the estimating unit 220. .

Here, according to the estimated downlink propagation attenuation (PL) for the aircraft terminal, how much to increase/decrease the uplink transmission power of the terminal 20 can be designed according to the optimization parameters unique to the communication provider.

According to an embodiment of the present invention, when a terrestrial terminal is located at the boundary of a base station where the interference problem is most pronounced, the distance between adjacent base stations is the closest. Therefore, in this case, the uplink interference strength of the terrestrial terminal to the adjacent base station is Considering that it will be the largest, it is possible to control the uplink transmission power so that the uplink interference of the aircraft terminal to the adjacent base station is lowered to the level of uplink interference that the ground terminal at the same distance from the service base station affects the adjacent base station.

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

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

Considering 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 aircraft terminal, that is, the terminal 20, the transmission power control unit 230 is the downlink estimated by the estimation unit 220 Based on the link propagation attenuation amount (PL) and the downlink signal strength transmitted by the serving base station 100, that is, the strength of the downlink CRS, the terminal 20 and the service base station through a free space propagation attenuation model as shown in Equation 3 above. The distance between (100) can be inverted.

And, the transmission power control unit 230, based on a pre-defined radio wave attenuation model, that is, a mobile communication radio wave attenuation model in a general terrestrial mobile communication environment such as Equation 2, the distance obtained by inverting the service base station 100 and the above ( It is possible to estimate the amount of downlink propagation attenuation for a specific terminal having a distance between the terminal 20 and the service base station 100).

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

That is, the transmission power control unit 230 assumes a ground terminal at the same distance as the terminal 20 that is an aircraft terminal, based on the service base station 100, and the downlink propagation attenuation for the ground terminal (Ground PL) Is to estimate.

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

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

In addition, the transmission power control unit 230 provides the determined correction value (e.g., -4dB) for the terminal 20 to the terminal 20, so that the terminal 20 is broadcasted from the service base station 100. It controls to reflect the correction value to the uplink transmission power previously determined based on the transmission power control setting.

As described above for a general uplink output control function, when the service base station 100 receives the transmission power control setting that is continuously broadcasting, the terminal 20, based on the received transmission power control setting, The radio wave attenuation between the and the serving 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 serving base station 100.

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

In this case, the terminal 20, which is an aircraft terminal, reflects a correction value (eg -4dB) to the transmission power determined based on the transmission power control setting according to the general uplink output control function, so that the uplink of the terminal 20 The uplink transmission power of the terminal 20 may be controlled so that the uplink interference caused by the transmission power to the adjacent base station is lowered to the uplink interference level that the terrestrial terminal having the same distance as the service base station 100 affects the adjacent base station.

At this time, according to an example, the transmission power control unit 230 uses the TPC (Transmit Power Control) command field in DCI (Downlink Control Information), which is a message used by the base station to control transmission power to individual terminals when necessary, (Example: -4dB) can be provided/applied to the terminal 20.

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

As described above, according to the transmission power control apparatus of the present invention, in the case of an aircraft terminal, in consideration of the propagation attenuation characteristic in which the increase rate of radio wave attenuation (amount) increases slowly compared to the ground terminal, It is realizing a new method to suppress strong ATG (Air to Ground) interference.

For this reason, according to the present invention, when a general uplink output control function is commonly applied to a ground/aircraft terminal, a ground mobile communication due to a larger air to ground (ATG) interference to an adjacent base station at the same distance Since the problem of relatively deteriorating service performance can be solved, the effect of maintaining a balanced ground/air mobile communication service performance is derived.

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

For convenience of explanation, the description is made by referring to the method of operating the transmission output device of the invention, and the reference number of the transmission output device is referred to as shown in FIG. 3, and the transmission power control device 200 is a base station (FIG. 1). It will be described with reference to an embodiment that is the same as 100) or is implemented to be included in the base station (100 of FIG.

First, according to the operating method of the transmission output device of the present invention, the transmission output device 200 (base station 100) uses SIB2, which is one of the channels for broadcasting system information of the base station, to set a predetermined transmission power control setting. Broadcasting and transmission (S100).

At this time, the information of the transmission power control setting includes 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 radio wave attenuation compensation setting. Included.

On the other hand, according to the operating method of the transmission output device of the present invention, the transmission output device 200 (base station 100), when the terminal (eg, terminal 20) accessing the base station 100 is recognized (S110), With respect to the terminal 20, it is checked whether it is an aircraft terminal corresponding to the aircraft terminal category (S120).

According to one example, the transmission output device 200, the base station 100, based on the QCI (QoS Class Identifier) given 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 assigned to a service, the terminal 20 to be accessed this time can be identified as an aircraft terminal.

According to the operating method of the transmission output device of the present invention, the transmission output device 200, the base station 100, if the terminal 20 to be connected this time is the aircraft terminal as a result of the confirmation in step S120 (S120 Yes), the terminal 20 ), the uplink transmission power control is performed to reduce the intensity of uplink interference to the adjacent base station (S130 to S150).

More specifically, the transmission output device 200 (base station 100) estimates a downlink propagation attenuation between the terminal 20 and the serving base station 100 for the terminal 20 identified as an aircraft terminal ( S130).

For example, the transmission output device 200, the base station 100, is used as a reference when the terminal 20 estimates the amount of radio wave attenuation, as mentioned in the description of information included in the transmission power control setting for broadcasting transmission. Knows the strength of the downlink CRS (RS _Level ).

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

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

Meanwhile, for CQI, two different tables are standardly defined according to whether or not the downlink modulation scheme uses 256QAM.

In addition, the downlink channel quality information, that is, CQI, that the terminal connected to the network reports to the serving base station at every set period, by definition, is an error with a probability within 10% of the transmission block at the terminal receiving end when transmitted from the base station. It means the maximum modulation and code rate that (Error) is likely to occur.

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

Accordingly, if the transmission output device 200 (base station 100) estimates the downlink signal-to-noise ratio (SNR) based on the mapping data (table) between the CQI and the downlink signal-to-noise ratio (SNR), the estimated downlink signal band Downlink propagation attenuation (PL) between the terminal 20 and the serving 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 figure (Thermal_Noise). Can be calculated (S130).

According to the operating method of the transmission output device of the present invention, the transmission output device 200, the base station 100, uses the downlink radio wave attenuation amount (PL) estimated in step S130, and the correction value, that is, the uplink of the terminal 20 A correction value for controlling the transmission power is determined (S140).

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

And, the transmission output device 200, the base station 100, based on a pre-defined radio wave attenuation model, that is, a mobile communication radio wave attenuation model in a general terrestrial mobile communication environment such as Equation 2, the service base station 100 and the above-described It is possible to estimate a downlink propagation attenuation (Ground PL) for a terrestrial terminal having a distance obtained by inverse calculation (the distance between the terminal 20 and the service base station 100).

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

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

And according to the operating method of the transmission output device of the present invention, the transmission output device 200, the base station 100, by providing the determined correction value (eg -4dB) for the terminal 20 to the terminal 20 (S150 ), the terminal 20 controls to reflect the correction value to the predetermined uplink transmission power based on the transmission power control setting transmitted from the service base station 100 (S160).

At this time, according to an example, the transmission output device 200 (base station 100) is a TPC (Transmit Power Control) command field in DCI (Downlink Control Information), which is a message used by the base station to control transmission power to individual terminals when necessary. Using, a correction value (eg -4dB) can be provided/applied to the terminal 20 (S150).

As described above for a general uplink output control function, when the service base station 100 receives the transmission power control setting that is continuously broadcast, the terminal 20 is configured with itself and the service base station based on the received transmission power control setting. The radio wave 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 serving base station 100.

At this time, the terminal 20 is a correction value (e.g., -4dB) received from the transmission power control apparatus 200 of the present invention to the uplink transmission power previously determined based on the transmission power control setting transmitted from the service base station 100 Can be reflected (S160).

In this case, the terminal 20, which is an aircraft terminal, reflects a correction value (eg -4dB) to the transmission power determined based on the transmission power control setting according to the general uplink output control function (S160), the terminal 20 The uplink transmission power of the terminal 20 can be controlled so that the uplink interference of the uplink transmission power of the adjacent base station is lowered to the uplink interference level that the terrestrial terminal of the same distance as the service base station 100 affects the adjacent base station. have.

On the other hand, according to the operating method of the transmission output device of the present invention, the transmission output device 200 (base station 100) is a case where the terminal to be accessed is not an aircraft 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 power control setting according to a general uplink output control function as in the past (S165).

As described above, according to the operating method of the transmission power control device according to the present invention, in the case of an aircraft terminal, in consideration of the propagation attenuation characteristic in which the increase rate of radio wave attenuation (amount) according to the distance increases slowly compared to the ground terminal, the vehicle terminal By realizing a new method to suppress strong ATG (Air to Ground) interference generated from the network, the effect of maintaining a balanced ground/air mobile communication service performance is derived.

The method of operating the transmission power control apparatus according to an embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and 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 usable 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 and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

Although the present invention has been described in detail with reference to preferred embodiments so far, the present invention is not limited to the above-described embodiments, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the following claims. Anyone with ordinary knowledge will say that the technical idea of the present invention extends to the range in which various modifications or modifications are possible.

According to the operating method of the transmission power control device and the transmission power control device of the present invention, in that it is possible to balance the ground/air mobile communication service performance by suppressing strong ATG (Air to Ground) interference generated from the aircraft terminal, As it goes beyond the limitations of the existing technology, it is an invention that has industrial applicability because not only the use of the related technology, but also the possibility of marketing or sales of the applied device is sufficient, and it can be practically and clearly implemented.

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

Claims (12)

With respect to the terminal accessing the service base station, a terminal identification unit for checking whether the radio wave attenuation amount 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; And
When the terminal corresponds to the first terminal category, the terminal comprises a control unit for performing uplink transmission power control to reduce the intensity of the uplink interference to the neighboring base station,
The control unit,
A downlink propagation attenuation amount estimated for the terminal corresponding to the first terminal category and a downlink propagation attenuation amount estimated for a specific terminal corresponding to a second terminal category in which the radio wave attenuation amount among the plurality of terminal categories is greater than a specific threshold attenuation amount Transmission power control apparatus, characterized in that to control the uplink transmission power of the terminal by using. The method of claim 1,
The control unit,
When the terminal corresponds to the first terminal category, an estimation unit estimating a downlink propagation attenuation between the terminal and the serving base station,
And a transmission power controller configured to control an uplink transmission power of the terminal to reduce an intensity of uplink interference to an adjacent base station by using the estimated downlink propagation attenuation. The method of claim 1,
The terminal verification unit,
Based on the QCI (QoS Class Identifier) assigned 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, it is identified as a first terminal category. Transmission power control device. The method of claim 2,
The transmission power control unit,
Provides a correction value determined using the estimated downlink propagation attenuation to the terminal,
And controlling the terminal to reflect the correction value to a predetermined uplink transmission power based on a transmission power control setting transmitted from a service base station. The method of claim 4,
The transmission power control unit,
Using the estimated distance between the terminal and the serving base station based on the estimated downlink propagation attenuation amount and the downlink signal strength transmitted by the serving base station, the distance from the serving base station is determined based on a predefined propagation attenuation model. Estimating the amount of downlink propagation attenuation for a specific terminal having,
A difference between the estimated downlink propagation attenuation amount and the estimated downlink propagation attenuation amount for a specific terminal is determined as the correction value,
The specific terminal,
And a terminal corresponding to a second terminal category in which a radio wave attenuation amount among the plurality of terminal categories is greater than a specific threshold attenuation amount. The method of claim 2,
The estimation unit,
And calculating and estimating a downlink propagation attenuation between the terminal and the serving base station based on downlink channel quality information (CQI) reported by the terminal to the serving 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 serving base station Using the century,
And calculating a downlink propagation attenuation amount for the terminal. ◈ Claim 8 was abandoned upon payment of the set registration fee. A terminal identification step of confirming whether a radio wave attenuation amount corresponds to a first terminal category less 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
A propagation attenuation amount estimating step of estimating a downlink propagation attenuation between the terminal and the serving base station when the terminal corresponds to the first terminal category; And
Using the estimated downlink propagation attenuation amount, a transmission power control step of controlling an uplink transmission power of the terminal so that an intensity of uplink interference to an adjacent base station is reduced,
The control step,
A downlink propagation attenuation amount estimated for the terminal corresponding to the first terminal category and a downlink propagation attenuation amount estimated for a specific terminal corresponding to a second terminal category in which the radio wave attenuation amount among the plurality of terminal categories is greater than a specific threshold attenuation amount The method of operating a transmission power control apparatus, characterized in that controlling the uplink transmission power of the terminal by using. ◈ Claim 9 was abandoned upon payment of the set registration fee. The method of claim 8,
The transmission power control step,
Provides a correction value determined using the estimated downlink propagation attenuation to the terminal,
And controlling the UE to reflect the correction value to a predetermined uplink transmission power based on a transmission power control setting transmitted from a service base station. ◈ Claim 10 was abandoned upon payment of the set registration fee. The method of claim 9,
The transmission power control step,
Using the estimated distance between the terminal and the serving base station based on the estimated downlink propagation attenuation amount and the downlink signal strength transmitted by the serving base station, the distance from the serving base station is determined based on a predefined propagation attenuation model. Estimating the amount of downlink propagation attenuation for a specific terminal having,
A difference between the estimated downlink propagation attenuation amount and the estimated downlink propagation attenuation amount for a specific terminal is determined as the correction value,
The specific terminal,
The operating method of the transmission power control apparatus, characterized in that the terminal corresponding to the second terminal category, the radio wave attenuation amount of the plurality of terminal categories is greater than a specific threshold attenuation amount. ◈ Claim 11 was abandoned upon payment of the set registration fee. The method of claim 8,
The radio wave attenuation amount estimating step,
Based on the downlink channel quality information (CQI) reported by the terminal to the serving base station, a downlink propagation attenuation amount between the terminal and the serving base station is calculated and estimated. . ◈ Claim 12 was abandoned upon payment of the set registration fee. The method of claim 11,
The radio wave attenuation amount 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 serving base station Using the century,
A method of operating a transmission power control apparatus, characterized in that calculating a downlink propagation attenuation amount for the terminal.

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