KR102030779B1 - Military distributed base station for ICI-recognition based adaptive transmit power control scheme - Google Patents

Abstract

Provided are military distributed base stations for interference recognition based adaptive transmit power control. The communication interface allows the serving cell to be formed using the maximum power for downlink communication, and communicates with user terminals located in the serving cell, and the memory changes the transmit power based on the recognition of inter-cell interference, A cell zooming program for performing Cell Zooming, a list of user terminals located at the edge of the serving cell managed by RRM (Radio Resource Management) (hereinafter referred to as a 'cell edge terminal list'), and a serving cell The interfering cell group of neighboring cells using the same frequency as the serving cell among neighboring cells is stored, and the processor executes a cell zooming program, which is measured by user terminals belonging to the interfering cell group and located at the edge of the serving cell. Average of Signal Received Power (RSRP) of neighboring cell (hereinafter referred to as' Neighbor Cell Average RSRP ') and average of RSRP of serving cell (hereinafter referred to as' Serving Cell Rating) Average RSRP '), and the calculated neighbor cell average RSRP and the serving cell average RSRP may be compared to determine a cell zoom-in of the serving cell based on a comparison result.

Description

Military distributed base station for ICI-recognition based adaptive transmit power control scheme

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a military distributed base station for interference-based adaptive transmission power control. More particularly, the present invention relates to interference-based adaptive transmission in which a base station can adjust cell coverage by controlling transmission power by itself in a wireless communication system. A military distributed base station for power control.

The commercial mobile communication system consists of a backbone network, a base station, and a terminal for providing a communication service in a wireless environment.

The base station is a communication facility that connects the main network and the terminal and is fixedly installed on land. The base station controls and manages the cell area in addition to the interface function between the main network and the terminal within a predetermined cell. Functions for controlling and managing a responsible cell zone include incoming / outgoing signal transmission, call channel designation, call channel monitoring, self-diagnosis functions, and the like.

In recent years, researches have been conducted to carry out effective combat by applying such mobile communication equipment and technology to military environments. In particular, developed countries including the United States are striving to apply commercial mobile communication systems with the aim of Network Centric Warfare (NCW).

Currently, the ROK military is building a future communication structure by developing a Tactical Information Communication Network (TICN) system, and developing a Tactical Mobile Communication System (TMCS) applying the WiBro communication standard.

The tactical mobile communication system includes a mobile subscriber access point (MSAP) corresponding to a commercial base station and a tactical multi-functional terminal (TMFT) corresponding to a user terminal device.

However, in the existing commercial military environment, base stations are fixedly installed to provide mobile communication services and communication between base stations is performed through a wired / wireless backbone backbone network.

In the existing military and commercial communication networks, base stations are arranged according to the optimal method that is pre-planned, and frequency resources are divided into inner and outer cells for each base station to avoid interference as much as possible. It is to be assigned.

However, the existing inter-cell interference management method efficiently manages interference by stably transmitting control signals through wired backhaul, and proposes a transmission power control technique for managing inter-cell interference by stably transmitting control signals in wireless backhaul. I'm not doing it.

Domestic Patent No. 10-1689182 (registered on March 4, 2010)

The technical problem to be solved by the present invention in order to solve the above-described problems, each base station determines itself in the environment not only the communication between the base stations, but also wireless backhaul communication zoom in (zoom in) or zoom out ( The present invention provides a military distributed base station for interference perception-based adaptive transmit power control.

In addition, the technical problem to be achieved by the present invention, the neighbor cell average signal received power (RSRP) value of the UE (User Equipment) present in the cell boundary when neighboring cell interference (ICI :) occurs than the average RSRP of the serving cell The present invention proposes a military distributed base station for adaptive perception-based adaptive transmission power control capable of inter-cell interference management by zooming in a cell step by step.

The problem of the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

As a means for solving the above-described technical problem, according to an embodiment of the present invention, the method for adaptive transmission power control based on interference perception of a military distributed base station, (A) the military distributed base station, for downlink communication Forming a serving cell using the maximum power; (B) determining, by the military distributed base station, neighboring cells using the same frequency as the serving cell among neighboring cells of the serving cell formed by the maximum power as an interference cell; (C) The military distributed base station, the average of the Signal Received Power (RSRP) of the neighbor cell measured by the user terminals located at the edge (edge) of the serving cell (hereinafter referred to as 'neighbor cell average RSRP') Calculating c); (D) calculating, by the military distributed base station, an average of the RSRP of the serving cell measured by user terminals located at the edge of the serving cell (hereinafter, referred to as a 'serving cell average RSRP'); And (E) comparing the neighbor cell average RSRP and the serving cell average RSRP by the military distributed base station to determine a cell zoom-in of the serving cell according to a comparison result.

In step (E), if the neighboring cell average RSRP is larger than the serving cell average RSRP, the military distributed base station processes the coverage of the serving cell to be zoomed in by reducing the maximum power.

The military distributed base station, wherein the neighboring cell average RSRP is greater than the serving cell average RSRP, the lowest data rate among the user terminals located at the edge of the serving cell than the minimum data rate that the user terminals can withstand If greater than or equal to, the coverage of the serving cell is processed to zoom in.

The military distributed base station verifies the zoom-in weight stored in the mapping between the neighbor cell average RSRP and the serving cell average RSRP from a zoom-in weight table, and reduces the maximum power according to the checked zoom-in weight.

At least one of the steps (C) to (E) is performed when it is determined that the military distributed base station does not perform wireless backhaul communication with the base stations of the neighboring cells.

In step (C), the military distributed base station includes user terminals located at the edge of the serving cell and also located at the interference cell, and users located at the edge of the serving cell but not at the interference cell. The neighbor cell average RSRP and the serving cell average RSRP are calculated using the neighbor cell RSRPs and the serving cell RSRPs measured by the terminals, respectively.

On the other hand, according to another embodiment of the present invention, the military distributed base station for interference-based adaptive transmission power control, so that the serving cell is formed by using the maximum power for the downlink communication, located in the serving cell A communication interface in communication with the user terminals; A cell zooming program that performs cell zooming by changing transmission power based on intercell interference recognition, and a list of user terminals located at an edge of a serving cell managed by RRM (Radio Resource Management) A memory for storing an interference cell group including a neighboring cell using the same frequency as the serving cell among neighboring cells of the serving cell; And executing the cell zooming program to determine an average of Signal Received Power (RSRP) of neighbor cells measured by user terminals belonging to the interference cell group and located at the edge of the serving cell (hereinafter, 'neighbor cell average RSRP'). And the average of the serving cell RSRP (hereinafter referred to as 'serving cell average RSRP'), and comparing the calculated neighboring cell average RSRP and serving cell average RSRP and zooming in the serving cell according to a comparison result. It includes; a processor for determining (Cell Zoom-In).

If the neighbor cell average RSRP is greater than the serving cell average RSRP, the processor reduces the maximum power and processes the coverage of the serving cell to zoom in.

When it is determined that the military distributed base station does not perform wireless backhaul communication with the base stations of the neighboring cells, the processor performs zoom-in of the serving cell by comparing the neighboring cell average RSRP and the serving cell average RSRP.

According to the present invention, the mobile base station can recognize the surrounding situation by itself, and can control the cell size of the base station according to a predetermined criterion by itself even in a situation where the backhaul communication with the neighboring base station is not performed. It can be controlled efficiently.

In addition, according to the present invention, while the base station is aware of the interference situation of the cell to prevent performance degradation due to the surrounding interference, in addition, there is an effect that can minimize the outage of the UE in the base station.

In addition, according to the present invention, when neighbor cell interference occurs, when the neighbor cell average RSRP value of the UE existing at the cell boundary is higher than the average RSRP of the serving cell, the adaptive power control can be performed by zooming in the cells step by step. There is.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is an exemplary diagram illustrating a cell environment in which inter-cell interference (ICI) occurs in a cell environment to which a military distributed base station for adaptive perception-based adaptive transmission power control according to an embodiment of the present invention is applied. ,
FIG. 2 is a diagram illustrating an example of a new environment in which cell B is zoomed in due to a change in transmit power of a second base station shown in FIG. 1;
3 is a flowchart illustrating a method for controlling interference based adaptive transmission power of a military distributed base station according to an embodiment of the present invention;
4 is a flowchart illustrating a method for controlling interference based adaptive transmission power of a military distributed base station according to another embodiment of the present invention;
5 is a block diagram schematically illustrating a military distributed base station for interference recognition based adaptive transmission power control according to an embodiment of the present invention;
6 is a functional block diagram of a military distributed base station according to an embodiment of the present invention shown in FIG. 5, and
7 is a functional block diagram illustrating the operation of a cell edge terminal.

Objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

Where the terms first, second, etc. are used herein to describe the components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

In addition, when it is mentioned that a first element (or component) is operated or executed on a second element (or component), the first element (or component) is a second element (or component). It is to be understood that the operation or execution in the environment in which the operation or the execution is performed or the operation or execution is performed through direct or indirect interaction with the second element (or component).

Where an element, component, device, or system is referred to as including a component made up of a program or software, even if no explicit mention is made, the element, component, device, or system may be executed or operated by the program or software. It should be understood to include the hardware necessary to run (eg, memory, CPU, etc.) or other programs or software (eg, an operating system or drivers needed to run the hardware, etc.).

In addition, it is to be understood that an element (or component) may be implemented in software, hardware, or any form of software and hardware, unless otherwise specified in the implementation of any element (or component).

Also, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the words 'comprises' and / or 'comprising' do not exclude the presence or addition of one or more other components.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In describing the following specific embodiments, various specific details are set forth in order to explain and understand the invention in more detail. However, those skilled in the art can understand that the present invention can be used without these various specific details.

In some cases, it is mentioned in advance that parts of the invention which are commonly known in the description of the invention and which are not highly related to the invention are not described in order to prevent confusion in explaining the invention without cause.

Hereinafter, specific technical contents to be implemented in the present invention will be described in detail with reference to the accompanying drawings.

Each configuration of the military distributed base station 500 for interference perception-based adaptive transmission power control illustrated in FIGS. 5 to 7 is functional and logically separated, and each configuration is necessarily a separate physical. It will be easy for the average person skilled in the art to infer that it is not meant to be divided into devices or written in separate codes.

In addition, in the present specification, a terminal is a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a user device. A user equipment (UE), an access terminal (AT), and the like may also be referred to, and may include all or some functions of a mobile terminal, a subscriber station, a portable subscriber station, a user device, and the like.

In addition, in the present specification, a base station (BS) includes an access point (AP), a radio access station (RAS), a node B (Node B), a base transceiver station (BTS), It may also refer to MMR (Mobile Multihop Relay) -BS, terminal integrated mobile base station, and the like, and includes all or part of functions such as access point, radio access station, NodeB, transceiver base station, MMR-BS, terminal integrated mobile base station, and the like. You may.

A program for implementing an operation of the military distributed base station 500 for the interference-based adaptive transmission power control may be installed in a predetermined data processing apparatus to implement the technical idea of the present invention.

1 is an exemplary diagram illustrating a cell environment in which inter-cell interference (ICI) occurs in a cell environment to which a military distributed base station for adaptive perception-based adaptive transmission power control according to an exemplary embodiment of the present invention is applied. to be.

Referring to FIG. 1, the first to third base stations BS (A), BS (B), and BS (C), which are military distributed base stations, each of the cells Cell A and Cell B according to the amount of power transmitted. , Cell C). In the serving cell Cell A of the first base station BS (A), first to fourth user terminals UE 1 (A), UE 2 (A), UE 3 (A), and UE 4 (A) The first user terminal UE 1 (B) is located in the serving cell Cell B of the second base station BS (B), and the serving cell Cell C of the third base station BS (C). ) Are the first and second user terminals UE 1 (C) and UE 2 (C).

In the cell environment as shown in FIG. 1, a mobile base station (eg, a first to third base stations BS (A), BS (B), and BS (C)) is arranged without frequency selection or uses the same frequency. For example, at least one of UE 1 (A) to UE 4 (A), UE 1 (B), UE 1 (C), and UE 2 (C)) is shown.

In the case of FIG. 1, 'f1' is used as the same frequency to generate inter-cell interference (ICI), and in this case, the first to third base stations BS (A), BS (B), and BS ( C)) may occur an environment where wireless backhaul communication is not possible.

Therefore, in the embodiment of the present invention, the first to third base stations BS (A), BS (B), and BS (C) are not only in communication with each other but also in environments without wireless backhaul communication. The three base stations BS (A), BS (B), and BS (C) may determine and perform cell zoom in or cell zoom out, respectively, at their own discretion.

Cell zooming technology including cell zoom-in or cell zoom-out is a technology capable of increasing energy efficiency of a self organization network (SON) in a small cell interference control environment (UDN: Ultra Dense Network). Cell Zooming technology has been studied mainly to improve the energy efficiency until now, and the present invention is proposed as a technology considering the ICI.

In the distributed evolved packet system (DEPS) environment, cell zooming is required to efficiently control not only energy efficiency but also inter-cell interference coordination (ICIC) in consideration of the characteristic communication environment of the military.

That is, an embodiment of the present invention considers cell zooming in an environment with ICI. Since the environment with ICI, that is, the environment in which inter-cell interference exists, is an environment in which neighboring base stations using the same frequency exist, it should be considered that there is a possibility that mutual communication is not possible between the base stations where the ICI occurs.

Accordingly, in the environment proposed by the embodiment of the present invention, each of the first to third base stations BS (A), BS (B), and BS (C) may provide a function of zooming in or out of a cell by determining itself. Can be. To this end, when ICI occurs in the serving cell (eg, Cell A), the first base station BS (A) determines that the neighboring cell average RSRP of the user terminals existing at the cell edge is the average of the serving cell. If it is higher than RSRP, the serving cell (Cell A) may be zoomed in stepwise to perform inter-cell interference coordination even in an environment where wireless backhaul communication is not possible.

In FIG. 1, considering a neighboring base station situation of a first user terminal UE 1 (A) and a second user terminal UE 2 (A) located at an edge of cell A, cell A is a cell B. Being interfered with by The third user terminal UE 3 (A) and the fourth user terminal UE 4 (A) are located at the edge but there is no interference.

Considering the surrounding base station situation of the first user terminal UE 1 (B) located at the edge of cell B, cell B is interfered by cell A.

In addition, considering the situation of neighboring base stations of the first user terminal UE 1 (C) and the second user terminal UE 2 (C) located at the edge of the cell C, the cell C is determined by the cell A and the cell B; At the same time, interference is occurring.

In order to solve the inter-cell interference problem, each of the first to third base stations BS (A), BS (B), and BS (C) according to an embodiment of the present invention does not consider only the state of individual user terminals. Do not. That is, cell zoom-in or cell zoom-out is performed in consideration of an interference situation of a user terminal (hereinafter, referred to as a 'cell edge terminal') located at an entire cell edge. Consider RSRP. The average RSRP of a neighboring cell is an average of RSRP measurements measured by each cell edge user terminal for all neighboring cells.

For example, in the case of cell A, the third user terminal UE 3 (A) and the fourth user terminal UE 4 (A) are located at the edge of the cell A without interference. The third user terminal UE 3 (A) and the fourth user terminal UE 4 (A) are present in the deep fading by shadowing or small scale fading, and thus close to the receiver sensitivity level. If receiving a signal from (A)), the first base station BS (A) will not attempt to zoom in the cell.

This means that if the third user terminal UE 3 (A) and the fourth user terminal UE 4 (A) are located at the edge and communicate with each other, the first base station BS (A) has a call blocking rate. (Blocking Probability, SINR> SINR _th ) may not be reduced in size. Signal to Interference plus Noise Ratio (SINR) is a signal-to-noise interference ratio, which is considered as interference noise, and SINR _th is a threshold of signal-to-noise interference ratio for determining call blocking.

Particularly, in case of cell A, when the operation proposed by the embodiment of the present invention is applied, the third user terminal UE 3 (A) and the third user terminal (UE 3 (A)) may be considered, considering the neighboring RSRP average value, that is, the RSRP average value of the neighboring cell. The neighboring RSRP average value is lowered by the 4 user terminal UE 4 (A), and in this case, the first base station BS (A) does not attempt to zoom in the cell. Since the RSRP of the neighbor cell B measured by the third user terminal UE 3 (A) and the fourth user terminal UE 4 (A) will be small, the first to fourth user terminals located in the cell A ( This is because the average of RSRP measured for cell B of UE 1 (A) to UE 4 (A) is lowered.

In the case of cell B, since it interferes with cell edge terminals (for example, UE 1 (A), UE 2 (A), UE 1 (C)), and UE 2 (C) located in other neighboring cells, The neighboring RSRP average value is likely to be higher than the average RSRP of the serving cell Cell B, and therefore the second base station BS (B) is likely to attempt cell zoom-in.

That is, according to an embodiment of the present invention, the base station (for example, the second base station (BS (B))) is adjacent to the base stations (for example, the first and third base stations (BS (A)) ), BS (B))) may be measured to determine cell zoom in or cell zoom out.

In particular, since a user terminal may generate an outage when the cell is zoomed in, the second base station BS (B) determines the minimum data rate that the user terminal with the lowest data rate can withstand and thus outages as much as possible. Can be prevented from occurring.

FIG. 2 is a diagram illustrating an example of a new environment in which cell B is zoomed in due to a change in transmit power of the second base station BS (B) shown in FIG. 1.

Referring to FIG. 2, when cell B zooms in, cell deployment may occur. According to an embodiment of the present invention, the second base station BS (B) compares the average RSRP of the neighboring cell with the average RSRP of the serving cell, and according to the comparison result, the first user terminal UE 1 at the edge of the cell B (UE 1). Zoom-in is performed so that outage does not occur in (B)), thereby reducing interference between cells A and C from cell B.

3 is a flowchart illustrating a method for controlling interference based adaptive transmission power of a military distributed base station according to an exemplary embodiment of the present invention.

The military distributed base station shown in FIG. 3 may be each of the first to third base stations BS (A), BS (B), and BS (C) shown in FIGS. 1 and 2. That is, the first to third base stations BS (A), BS (B), and BS (C) shown in FIG. 1 independently control interference recognition based adaptive transmission power according to an embodiment of the present invention. Cell zoom-in or cell zoom-out.

In addition, in FIG. 3, for example, if the military distributed base station is the first base station BS (A), the serving cell is cell A, and the neighboring cells are the second base station BS (B) and the third base station BS. It may be a cell B and a cell C formed by (C)).

Referring to FIG. 3, the military distributed base station forms a serving cell using the maximum power for downlink communication (S310).

Once the serving cell is formed, the military distributed base station may determine neighboring cells using the same frequency as the serving cell among the neighboring cells of the serving cell formed by the maximum power as an interference cell (S320).

Referring to step S320 in more detail, the military distributed base station can obtain information on the cell edge terminal by transmitting an RRM Request message to RRM (Radio Resource Management) (S321). In the case of FIG. 3, the cell edge terminal located in the serving cell of the military distributed base station includes a first user terminal and a second user terminal. Alternatively, at least one of the first user terminal and the second user terminal may be located at the cell edge but not at the interfering cell.

The military distributed base station may transmit a scan request message to the first user terminal and the second user terminal located at the edge of the cell they serve according to the information obtained in step S321 (S322 and S323). The Scan Request message is a message for requesting content including RSRP information, Received Signal Strength Indication (RSSI) information, a neighbor cell list, and the like, and may be referred to as a PHY Request message because it is transmitted to cell edge terminals.

When the first user terminal receives the Scan Request message, the first user terminal may generate a neighbor cell list, measure RSRP of the neighbor cell for each neighbor cell, and measure RSRP and RSSI of the serving cell (S324).

The first user terminal may transmit a scan result message including the generated neighbor cell list, RSSI, RSRP of the serving cell, and RSRP of the neighbor cell to the military distributed base station (S325).

The second user terminal may also generate the neighbor cell list, measure the RSSI, the RSRP of the serving cell, and the RSRP of the neighbor cell, and transmit the same to the military distributed base station (S326 and S327).

The military distributed base station analyzes the received Scan Result message to update the Intra-Frequency Automatic Neighbor Relation (ANR) table, and creates an interference cell group (Gi) composed of cells using the same frequency as its own. The RRM may request to update the new interference cell list c * (S328). The interference cell list c * includes the number of previous interference cells and the number of added interference cell lists, and may be equal to the number of interference cells in the interference cell group Gi.

On the other hand, after step S320, the military distributed base station calculates the neighbor cell average RSRP (RSRP _{AVG_N} ) using the neighbor cell RSRPs received in steps S325 and S327, and the serving cell average RSRP using the serving cell RSRPs (RSRP _{AVG_S).} ) Is calculated (S330).

In step S330, the military distributed base station may calculate the neighboring cell average RSRP using Equation 1.

In Equation 1, i is the index of the user terminal located at the edge of the serving cell, I is the number of user terminals located at the cell edge (maximum index), n is the index of the neighbor cell of the i-th cell edge terminal, N means the number of neighbor cells, RSRP _{i, N} means the RSRP of the neighbor cell.

In addition, the military distributed base station may calculate the serving cell average RSRP using Equation (2).

In Equation 1, i is the index of the user terminal located at the edge of the serving cell, I is the number of user terminals located at the cell edge (maximum index), n is the index of the neighbor cell of the i-th cell edge terminal, N is the number of neighbor cells, RSRP _{i, S} means the RSRP of the serving cell.

Military distributed base station may determine the zooming of the serving cell according to the comparison result by comparing the average RSRP _{(AVG_S} RSRP) of the average RSRP (RSRP _{AVG_N)} and a serving cell in the neighboring cells calculated (S340).

In more detail the S340 step, military distributed base station to reduce the maximum power in the average RSRP (RSRP _{AVG_N)} of the neighboring cell is greater than the average RSRP (RSRP _{AVG_S)} of the serving cell (S341-Yes), step S310 In operation S343, the coverage of the serving cell may be zoomed in.

In particular, in order to minimize occurrence of outages of user terminals located in the serving cell, the military distributed base station is larger than the average RSRP (RSRP _{AVG_S} ) of the serving cell (S341- _A ). Yes) At the same time, if the lowest data rate DR _WOR among the cell edge terminals (ie, the first and second user terminals) is greater than or equal to the minimum data rate DR _MIN that the user terminal can tolerate (S342). -Yes) it is possible to determine the zoom-in of the serving cell (S343). Step S342 may be omitted.

On the other hand, the military distributed base station, the average of neighboring cell RSRP (RSRP _{AVG_N)} that is below the average RSRP (RSRP _{AVG_S)} of the serving cell (S341-No), or the lowest data rate of the first and second user terminals If the DR _WOR is smaller than the minimum data rate DR _MIN that the user terminal can withstand (S342-No), the size of the serving cell may be maintained (S344).

In step S343, the military distributed base station may check the zoom-in weight stored in the zoom-in weight table mapped to the difference between the average RSRP of the neighboring cell and the average RSRP of the serving cell, and reduce the maximum power according to the checked zoom-in weight table. The zoom-in weight table may be prepared in advance, and the greater the difference between the average RSRP of the neighboring cell and the average RSRP of the serving cell, the greater the zoom-in weight. As a result, the military distributed base station may adjust the serving cell size by adaptively changing the transmission power according to the difference between the average RSRP of the neighboring cell and the average RSRP of the serving cell, and minimize the outage of the user terminal.

In addition, the military distributed base station can solve the problems caused by the ICI by performing the independent cell zooming by performing steps S310 to S340 not only in the communication with neighboring cells but also in an environment where wireless backhaul communication is not permitted.

4 is a flowchart illustrating a method of controlling interference based adaptive transmission power of a military distributed base station according to another embodiment of the present invention.

The adaptive transmission power control method based on interference perception of the military distributed base station to be described with reference to FIG. 4 is similar to the adaptive transmission power control method described with reference to FIG. 3, and thus a detailed description thereof will be omitted.

Referring to FIG. 4, the military distributed base station forms a serving cell using the maximum power for downlink communication (S410).

When the serving cell is formed, the military distributed base station may prepare an ANR table through a general data communication process and calculate a call blocking rate B of user terminals located in the serving cell (S420).

The military distributed base station may determine neighboring cells using the same frequency as the serving cell among neighboring cells of the serving cell as an interference cell (S430).

Referring to step S430 in more detail, the military distributed base station can obtain information about the cell edge terminals, that is, the first user terminal and the second user terminal located at the edge of the serving cell from the RRM (S431).

The military distributed base station may transmit a scan request message to the first user terminal and the second user terminal (S432 and S433).

When the first user terminal and the second user terminal receive the Scan Request message, the first user terminal and the second user terminal generate the neighbor cell list, measure the RSRP of the neighbor cell for each neighbor cell, measure the RSRP and RSSI of the serving cell, and generate the neighbor cell list. The scan result message including the RSSI, the RSRP of the serving cell, and the RSRP of the neighboring cell may be transmitted to the military distributed base station (S434 to S437).

The military distributed base station analyzes the received Scan Result message to update the Intra-Frequency ANR table, creates an interfering cell group (Gi) of cells that use the same frequency as its neighbors, and creates a new interfering cell in the RRM. In operation S438, the list c * may be requested to be further updated.

The military distributed base station calculates a neighbor cell average RSRP (RSRP _{AVG_N} ) using the received neighbor cell RSRPs, and calculates a serving cell average RSRP (RSRP _{AVG_S} ) using the serving cell RSRPs (S440).

Military distributed base station may determine the zooming of the serving cell according to the comparison result by comparing the average RSRP _{(AVG_S} RSRP) of the average RSRP (RSRP _{AVG_N)} and a serving cell in the neighboring cells calculated (S450).

In more detail the S450 step, military distributed base station is greater than (S451-Yes), the cell edge terminal average RSRP (RSRP _{AVG_S)} of the serving cell, the average RSRP (RSRP _{AVG_N)} of the neighboring cell (i.e., the first and the 2) the lowest data rate DR _WOR is greater than or equal to the minimum data rate DR _MIN that the user terminal can tolerate, and the call blocking rate B calculated in step S420 is If it is less than or equal to the maximum blocking rate P that can be tolerated (S452-Yes), the zoom-in of the serving cell may be determined (S453).

Accordingly, even if the military distributed base station reduces the size of the cell, the cell size can be reduced when the DR _WOR is larger than the DR _MIN without violating the blocking condition by considering the blocking condition.

On the other hand, the military distributed base station, the average of neighboring cell RSRP (RSRP _{AVG_N)} that is below the average RSRP (RSRP _{AVG_S)} of the serving cell (S451-No), or the lowest data rate of the first and second user terminals (DR _WOR ) is less than the minimum data rate (DR _MIN ) that the user terminal can withstand (S452-No), or the call blocking rate (B) calculated in step S420 the cell edge terminal can endure the maximum If greater than the blocking rate (P) (S452-No), it is possible to maintain the size of the serving cell (S454).

5 is a block diagram schematically illustrating a military distributed base station 500 for interference recognition based adaptive transmission power control according to an embodiment of the present invention.

The military distributed base station 500 illustrated in FIG. 5 may correspond to each of the first to third base stations BS (A), BS (B), and BS (C) described with reference to FIGS. 1 and 2. And may be a military distributed base station described with reference to FIGS. 3 to 4.

Referring to FIG. 5, the military distributed base station 500 for interference recognition based adaptive transmission power control according to the present embodiment may include a communication interface 510, a memory 520, and a processor 530.

The communication interface 510 allows the serving cell to be formed using the maximum power for the downlink communication, and communicates with user terminals located in the serving cell. To this end, the communication interface 510 includes communication circuits.

The memory 520 may include volatile memory and / or nonvolatile memory. The memory 520 may include, for example, instructions or data related to the components 510-530, one or more programs, and the like to implement and / or provide the operations, functions, and the like provided by the military distributed base station 500. And / or software, operating system, and so forth.

The program stored in the memory 520 may include a cell zooming program that performs cell zooming by changing transmission power based on intercell interference recognition. In addition, the memory 520 includes an ANR table managing a neighboring cell list of the serving cell, a list of user terminals located at the edge of the serving cell managed by the RRM (hereinafter referred to as a cell edge terminal list), and a serving. An interference cell group including neighboring cells using the same frequency as the serving cell among neighboring cells of the cell may be stored.

The processor 530 executes one or more programs stored in the military distributed base station 500 to control the overall operation of the military distributed base station 500.

For example, the processor 530 executes a cell zooming program stored in the memory 520 in an environment in which wired / wireless communication with a base station of a neighboring cell or wireless backhaul communication is not possible, and belongs to an interfering cell group to the edge of the serving cell. An average of RSRPs of neighboring cells measured by located user terminals may be calculated, and an average of RSRPs of measured serving cells may be calculated. The processor 530 may compare the calculated average RSRP of the neighboring cell with the average RSRP of the serving cell to determine a cell zoom-in of the serving cell according to the comparison result.

In detail, if the average RSRP of the neighboring cell is larger than the average RSRP of the serving cell, the processor 530 may reduce the maximum power to process the coverage of the serving cell to be zoomed in.

Alternatively, the processor 530 may determine that the lowest data rate DR _WOR among user terminals (ie, cell edge terminals) located at the edge of the serving cell while the neighbor cell average RSRP is larger than the serving cell average RSRP. If they are greater than or equal to the minimum data rate (DR _MIN ) they can tolerate, the serving cell's coverage may be processed to zoom in.

Alternatively, the processor 530 may determine that the average RSRP of the neighbor cell is greater than the average RSRP of the serving cell, and the lowest data rate DR _WOR among cell edge terminals is greater than the minimum data rate DR _MIN that the user terminal can withstand. If the call blocking rate of the user terminals in the serving cell is greater than or equal to and equal to or less than the call blocking rate that the cell edge terminal can withstand as much as possible, the serving cell may be processed to zoom in.

FIG. 6 is a functional block diagram of the military distributed base station 500 according to the embodiment of the present invention shown in FIG. 5, and FIG. 7 is a functional block diagram for describing an operation of a cell edge terminal.

The controller, ANR, and RRM illustrated in FIG. 6 illustrate the functions of the processor 530 illustrated in FIG. 5, and the PHYs 600 and 600a of the Cell Edge UE are each distributed military base stations 500. It may mean the physical layer of the first user terminal and the physical layer of the second user located at the edge of the serving cell of the.

Referring to FIG. 6, the ANR of the military distributed base station 500 according to the present invention automatically finds neighboring neighbor base stations so that the UE can perform a handover. The cell received from the user terminals located in the serving cell Creates a list of neighboring cells using the list.

The RRM manages whether terminals located in the serving cell are terminals located at the cell edge or terminals located inside.

The controller may transmit an RRM Request message to the RRM to obtain information on cell edge terminals that it serves, and receive an RRM Respone message including information that can communicate with the cell edge terminals from the RRM.

The controller determines that the first user terminal 600 and the second user terminal 600a are the cell edge terminal from the cell edge terminal information included in the RRM response message, and the first user terminal 600 and the second user. The PHY request message may be transmitted to the terminal 600a. The PHY request message may be mixed with the Scan Request message as a message for requesting neighbor cell list information, RSSI, RSRP, and the like.

When the cell edge terminals 600 and 600a receive the PHY request message (or Scan Request message), the cell edge terminals 600 and 600a may perform a scanning function according to the block illustrated in FIG. 7. In FIG. 7, the first user terminal 600 will be described as an example.

Referring to FIG. 7, after receiving a PHY request message (or Scan Request message), the first user terminal 600 performs Received Signal Strength Indication (RSSI) measurement after setting up an RF carrier. The first user terminal 600 may acquire the neighbor cell ID after the PSS + SSS detection from the serving base station with respect to the signal equal to or greater than the RSSI threshold. The first user terminal 600 performs RSRP measurement using the acquired neighbor cell ID, performs MIB decoding and SIB decoding using the obtained cell ID, and obtains MIB (Master Information Block) information and SIB (System). Information Block) to obtain information. In addition, the first user terminal 600 may prepare the acquired information (neighbor cell list, neighbor cell ID, neighbor cell RSRP, serving cell RSRP, RSSI) as a Scan Result (or PHY Response) message and deliver the information to the controller.

The controller generates a Scan Response message that transfers the cell list from the received Scan Result message to the ANR and delivers it to the ANR. As such, the ANR updates the ANR table. In addition, the controller may store or manage the group Gi and the interference cell list c * of the cells in which the interference with the serving cell (that is, the interference cells) are received.

In addition, the controller calculates the neighbor cell average RSRP from the RSRPs of neighbor cells among the scan results (or PHY responses) received from the first user terminal 600 and the second user terminal 600a, and serves from the serving cell RSRPs. The cell average RSRP can be calculated.

If the average RSRP of the neighboring cell is greater than the average RSRP of the serving cell, the controller may reduce the power previously used for forming the serving cell to allow the serving cell to zoom in.

Or, if the average RSRP of the neighboring cell is larger than the average RSRP of the serving cell, and at the same time, the lowest data rate of the cell edge terminals (ie, the first and second user terminals) is greater than or equal to the minimum data rate. You can decide to zoom in.

Alternatively, the controller may determine that the call blocking rate of the user terminals can be tolerated by the cell edge terminals as much as possible, while the average RSRP of the neighboring cell is larger than the average RSRP of the serving cell, while the lowest data rate of the cell edge terminals is more than the minimum data rate. If the call blocking rate is less than or equal to, the serving cell may be determined to be zoomed in.

Meanwhile, according to the above-described embodiment of the present invention, the military distributed base station includes user terminals located at the edge of the serving cell and also located at the interference cell, and user terminals located at the edge of the serving cell but not at the interference cell. Using the neighbor cell RSRPs and the serving cell RSRPs measured by the above, it is possible to calculate the average RSRP of the neighboring cell and the average RSRP of the serving cell, respectively.

Alternatively, the military distributed base station uses neighbor cell RSRPs and serving cell RSRPs measured by user terminals located at the edge of the serving cell and also located in the interfering cell, respectively, and the average RSRP of the neighboring cell and the average RSRP of the serving cell, respectively. May be calculated.

Meanwhile, the method for adaptive transmission power control based on interference perception of a military distributed base station capable of cell zooming according to the present invention is included in a recording medium that can be read through a computer by programmatically implementing instructions for implementing the same. It may be easily understood by those skilled in the art that the present invention may be provided.

That is, the interference perception-based adaptive transmission power control method of a military distributed base station capable of cell zooming according to the present invention is implemented in a program form that can be executed by various computer means, and can be recorded on a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. The computer-readable recording medium may include magnetic media such as a hard disk, optical media such as a CD-ROM, and DVD, and ROM, RAM, flash memory, USB memory, and the like. Hardware devices specifically configured to store and execute program instructions are included.

Accordingly, the present invention provides a program stored in a computer-readable recording medium that is executed on a computer controlling the military distributed base station in order to implement an interference perception-based adaptive transmission power control method of a military distributed base station capable of cell zooming. do.

On the other hand, while described and illustrated in connection with a preferred embodiment for illustrating the technical idea of the present invention, the present invention is not limited to the configuration and operation as shown and described as described above, and depart from the scope of the technical idea It will be apparent to those skilled in the art that many modifications and variations can be made to the present invention without departing from the scope of the invention. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

BS (A), BS (B), BS (C): first to third base stations
UE: user terminal
500: military distributed base station 510: communication interface
520: memory 530: processor

Claims (6)

In the military distributed base station for interference recognition based adaptive transmission power control,
A communication interface for allowing a serving cell to be formed using a maximum power for downlink communication and for communicating with user terminals located in the serving cell;
A cell zooming program that performs cell zooming by changing transmission power based on intercell interference recognition, and a list of user terminals located at an edge of a serving cell managed by RRM (Radio Resource Management) A memory for storing an interference cell group including a neighboring cell using the same frequency as the serving cell among neighboring cells of the serving cell; And
By executing the cell zooming program, the average of Signal Received Power (RSRP) of neighbor cells measured by user terminals belonging to the interference cell group and located at the edge of the serving cell (hereinafter, referred to as 'neighbor cell average RSRP'). The average of the serving cell's RSRP (hereinafter, referred to as 'serving cell average RSRP'), and comparing the calculated neighboring cell average RSRP with the serving cell average RSRP and zooming in the serving cell according to a comparison result. A processor for determining Cell Zoom-In);
The processor,
As a result of the comparison, if the neighbor cell average RSRP is greater than the serving cell average RSRP, the lowest data rate among user terminals located at the edge of the serving cell is greater than or equal to the minimum data rate that the user terminals can withstand. Reducing the maximum power so that coverage of the serving cell is zoomed in,
If it is determined that the military distributed base station does not perform wireless backhaul communication with the base stations of the neighboring cells, the neighboring cell average RSRP and the serving cell average RSRP are compared to perform zoom-in of the serving cell. Military distributed base station for cognitive-based adaptive transmit power control.
delete delete The method of claim 1,
The processor may determine a zoom-in weight stored in a mapping between a difference between the neighboring cell average RSRP and the serving cell average RSRP from a zoom-in weight table, and reduce the maximum power according to the identified zoom-in weight. Military distributed base station for adaptive transmit power control.
delete The method of claim 1,
The processor,
Neighbor cell RSRPs and serving cell RSRPs measured by user terminals located at the edge of the serving cell and also located in the interfering cell, and user terminals located at the edge of the serving cell but not at the interfering cell. A military distributed base station for interference recognition based adaptive transmission power control, characterized in that for calculating the neighboring cell average RSRP and the serving cell average RSRP, respectively.

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