KR102501308B1 - Method and apparatus for predicting error and reconfiguring network based on data analysis - Google Patents

Abstract

A data analysis-based error prediction and network reconstruction method and apparatus are disclosed. A method of operating a serving base station supporting handover includes collecting radio link information between the terminal and the serving base station from a terminal, determining whether an error occurs in a radio link with the terminal based on the radio link information. If no error occurs in the radio link, calculating an expected value of occurrence of an error in the radio link, and if the expected value is greater than a first reference value, handover compatibility of neighboring base stations based on the radio link information Calculating , selecting a target base station based on the calculated handover suitability, and supporting handover of the terminal to the target base station.

Description

Data analysis-based error prediction and network reconstruction method and apparatus

The present invention relates to a method and apparatus for predicting errors and reconfiguring a network in a communication system, and more particularly, when a radio link error is predicted, a network is reconfigured to prevent the occurrence of a radio link error and provide quality of service in a stable manner. It's about how to improve.

A cellular mobile communication system may provide a handover technology in which a terminal arrives in a new cell and connects to a base station managing the new cell in order to provide uninterrupted service to a mobile terminal in motion. However, it may be difficult to quickly cope with various wireless environment changes occurring while the terminal is moving. Therefore, service interruption may occur.

Meanwhile, 3GPP applied a self-organizing network (SON) to the standard. The self-organizing network may aim to increase the economic efficiency of network coverage and transmission capacity expansion. Self-optimization of the self-organizing network is a function for improving transmission performance of the network and efficiently managing network resources by optimizing various parameters according to changes in the surrounding environment. Self-healing is a function of self-discovery and healing of obstacles such as transmission failure and transmission delay in the network.

An object of the present invention to solve the above problems is to provide a service quality improvement method that reconfigures a network when a radio link error is predicted to prevent the occurrence of a radio link error and stably provides a communication service.

To achieve the above object, a method of operating a serving base station supporting handover according to an embodiment of the present invention includes collecting radio link information between the terminal and the serving base station from a terminal, based on the radio link information Determining whether an error has occurred in the wireless link with the terminal, if no error has occurred in the wireless link, calculating an expected value where an error will occur in the wireless link, and when the expected value is greater than a first reference value , calculating handover suitability of neighboring base stations based on the radio link information, selecting a target base station based on the calculated handover suitability, and supporting handover of the terminal to the target base station. can do.

According to the present invention, an error prediction model in a communication system can be inferred using data collected in the past in the communication system. Measurement information collected from the terminal and situation information collected in real time from a radio access network (RAN) may be analyzed, and an error prediction model may be designed through the analyzed information. When an error in the communication system is predicted, the small cell base station may reconfigure the network by selecting another small cell base station capable of accommodating the ongoing service characteristics. If the occurrence of an error is predicted, preventive measures can be taken to prevent the occurrence of an error, so that communication services can be stably supported without interruption. Accordingly, the performance of the communication system can be improved.

1 is a conceptual diagram illustrating an embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a flowchart illustrating a process of generating a radio link error in a base station according to an embodiment of the present invention.
4 is a flowchart illustrating a method of predicting occurrence of a radio link error in a communication system according to an embodiment of the present invention.
5 is a flowchart illustrating a handover procedure according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. A communication system to which embodiments according to the present invention are applied is not limited to the contents described below, and embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same sense as a communication network.

1 is a conceptual diagram illustrating a first embodiment of a communication system.

Referring to FIG. 1, a communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 includes a core network (eg, a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), and a mobility management entity (MME)). can include more.

A plurality of communication nodes may support 4G communication (eg, long term evolution (LTE), advanced (LTE-A)), 5G communication, and the like specified in the 3rd generation partnership project (3GPP) standard. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. For example, for 4G communication and 5G communication, a plurality of communication nodes may use a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, FDMA (frequency division multiple access)-based communication protocol, OFDM (orthogonal frequency division multiplexing)-based communication protocol, Filtered OFDM-based communication protocol, CP (cyclic prefix)-OFDM-based communication protocol, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (non-orthogonal multiple access), GFDM (generalized frequency) Division multiplexing)-based communication protocol, FBMC (filter bank multi-carrier)-based communication protocol, UFMC (universal filtered multi-carrier)-based communication protocol, SDMA (space division multiple access)-based communication protocol, etc. can be supported. . Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , a communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, and the like. Each component included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each component included in the communication node 200 may be connected through an individual interface or an individual bus centered on the processor 210 instead of the common bus 270 . For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2), a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Base stations 110-1, 110-2, 110-3, 120-1, and 120-2 and terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 The inclusive communication system 100 may be referred to as an “access network”. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. there is. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, a gNB, an ng-eNB, and a BTS. (base transceiver station), radio base station, radio transceiver, access point, access node, road side unit (RSU), radio remote head (RRH), TP( transmission point), transmission and reception point (TRP), flexible (f)-TRP, and the like. Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a UE (user equipment), terminal, access terminal, mobile Mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, internet of things (IoT) It may be referred to as a device supporting a function, a mounted module/device/terminal, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, and , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to a corresponding terminal 130-1, 130-2, 130-3, and 130 -4, 130-5, 130-6), and signals received from corresponding terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 are transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) transmission, CA (carrier aggregation) transmission, transmission in an unlicensed band, device to device communication (D2D) (or ProSe ( proximity services)) may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 can transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 uses the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by CoMP. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes a terminal 130-1, 130-2, 130-3, and 130-4 belonging to its own cell coverage. , 130-5, 130-6) and a CA method. Hereinafter, a radio link failure (RLF) occurrence prediction method and avoidance method will be described.

The radio link error (RLF) between the base station and the terminal is the level of the reference signal received power (RSRP) received from the base station by the terminal, the number of radio link control (RLC) retransmissions, and the message periodically transmitted from the terminal (eg, It may be caused by a time when a channel quality indicator (CQI) or a scheduling request (SR) is not received, a time when a physical downlink control channel (PDCCH) block error rate (BLER) of the UE exceeds 10%, and the like. The base station can predict RLF occurrence using the signal strength level received from the base station by the terminal, the number of RLC retransmissions, the time when a message periodically transmitted from the terminal is not received, and the time when the PDCCH BLER of the terminal exceeds 10%. Equation 1 represents an RLF generation expected value prediction model.

Referring to Equation 1, the base station may calculate an expected RLF generation value based on the main causes of RLF generation. Independent variable x ₁ may mean the signal strength level of the base station received from the terminal, independent variable x ₂ may mean the number of RLC retransmissions, and independent variable x ₃ may indicate a message periodically transmitted from the terminal to the base station. may mean the time not received in , and the independent variable x ₄ may mean the time when the PDCCH BLER of the terminal exceeds 10%. The weights a, b, c, and d may be constant values for each independent variable (x ₁ , x _2, x _3, x ₄ ). The weights (ie, a, b, c, and d) may be determined prior to performing the error prediction process. The weight may be determined through a machine learning process based on accumulated independent variables (x ₁ , x _2, x _3, x ₄ ) and RLF generation data. Alternatively, the weight may be determined according to a system operation policy of a network operator. The error term ε is assumed to follow a normal distribution with mean 0 and variance σ ² .

The base station may calculate an expected RLF generation value according to Equation 1 based on information collected from the terminal in real time and independent variable (x ₁ , x _2, x _3, x ₄ ) information collected from the base station. The base station may reconfigure the network when RLF occurrence is predicted according to the RLF occurrence expectation value. The base station can prevent RLF through network reconfiguration. Next, a procedure for determining whether an RLF has occurred in a base station will be described.

3 is a flowchart illustrating an RLF generating process in a base station according to an embodiment of the present invention.

Referring to FIG. 3 , the communication system of FIG. 3 may be the same as or similar to the communication system of FIG. 1 . The terminal of FIG. 3 may be the communication nodes 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 of FIG. 1, and the base station of FIG. 3 is the communication node of FIG. 110-1, 110-2, 110-3, 120-1, 120-2).

The base station may initialize RLF information for the terminal (S301). The base station may collect RLF generation cause information of the terminal for which RLF information has been initialized (S302). RLF occurrence cause information may include the base station signal strength level measured by the terminal, the number of RLC retransmissions, the time when a message periodically transmitted from the terminal is not received by the base station, and the time when the PDCCH BLER of the terminal exceeds 10%.

The base station may compare the signal strength level of the base station received by the terminal with a preset reference value (S303). The base station may determine that an RLF has occurred when the signal strength level of the base station received by the terminal is equal to or less than a preset reference value, and may notify the terminal of the occurrence of RLF (S308).

The base station may compare the number of RLC retransmissions of the terminal with the preset reference number when the signal strength level of the base station received by the terminal is greater than a preset reference value (S304). If the number of RLC retransmissions of the terminal is equal to or greater than the preset reference number, the base station may determine that RLF has occurred and may notify the terminal of the occurrence of RLF (S308).

When the number of RLC retransmissions of the terminal is less than the reference number, the base station may compare the time at which a message periodically transmitted from the terminal is not received with a preset first reference time (S305). When the base station does not receive a message periodically transmitted from the terminal is longer than a preset first reference time (ie, when a message periodically transmitted from the terminal is not received within the first reference time), RLF is generated. It can be determined that it is, and the generation of RLF can be notified to the terminal (S308).

When the time at which the base station does not receive a message periodically transmitted from the terminal is less than a preset first reference time (ie, when a message periodically transmitted from the terminal is received within the first reference time), the PDCCH BLER of the terminal is 10 The time exceeding % may be compared with a preset second reference time (eg, T310) (S306). The base station may determine that the RLF has occurred, and notify the terminal of the occurrence of the RLF when the time for which the PDCCH BLER of the terminal exceeds 10% is longer than the second reference time (S308). The base station may perform an RLF occurrence prediction procedure when the time when the PDCCH BLER of the terminal exceeds 10% is equal to or less than the second reference time (S307).

S303 to S306 in which the base station determines whether RLF has occurred are not limited to the above-described order, and S303 to S306 may be performed in a different order. In addition, some steps of S303 to S306 may be omitted, and whether or not RLF has occurred may be determined by a method other than S303 to S306. Next, the RLF occurrence prediction procedure is described.

4 is a flowchart illustrating a method for predicting RLF occurrence by a base station according to an embodiment of the present invention.

Referring to FIG. 4 , the communication system of FIG. 4 may be the same as or similar to the communication system of FIG. 3 . It is assumed that the weights (a, b, c, d) according to Equation 1 have already been determined.

A series of procedures of FIG. 4 may be an RLF generation prediction procedure (S307) of FIG. 3 . The base station may calculate an expected RLF generation value of the terminal in real time, and may increase the RLF counter of the terminal (S401). The base station uses the main cause of RLF occurrence, the level of signal strength received from the base station by the terminal, the number of RLC retransmissions, the time when messages periodically transmitted from the terminal are not received, and the time and weight when the PDCCH BLER of the terminal exceeds 10% Thus, an expected RLF generation value of the UE can be calculated based on Equation 1. The weight may be predetermined.

The base station may compare the expected RLF generation value of the terminal with the RLF risk reference value (eg, 70) (S402). The base station may perform an RLF avoidance procedure when the RLF generation expected value of the terminal is greater than the RLF risk reference value (S407).

When the RLF occurrence expectation value of the terminal is smaller than the RLF risk reference value, the base station may compare the RLF occurrence expectation value of the terminal with the RLF monitoring reference value (eg, 40) (S403). The base station may initialize RLF information for the terminal when the expected RLF generation value of the terminal is smaller than the RLF monitoring reference value (S301). The base station may perform the procedure subsequent to S301 of FIG. 3 .

When the expected RLF generation value of the terminal is greater than the RLF monitoring reference value, the base station may check whether the RLF counter of the terminal is greater than the reference value (eg, 4) (S404). Since the RLF counter of the terminal increases by 1 each time the RLF occurrence prediction procedure is performed, the RLF counter of the terminal may indicate the number of times the RLF occurrence prediction procedure of the terminal is performed. If the RLF counter of the terminal is smaller than the reference value, the base station may initialize RLF information for the terminal (S301). The base station may perform the procedure subsequent to S301 of FIG. 3 .

When the RLF counter of the terminal is greater than the reference value, the base station can check the trend line of the expected RLF occurrence value of the terminal. RLF occurrence expected values may be calculated as many times as the number of times corresponding to the RLF counter of the terminal, and the calculated RLF occurrence expected values may be stored. The base station can compare the stored expected RLF occurrence values and check the trend line of the stored expected RLF occurrence values. The base station can determine whether the expected RLF occurrence value of the terminal is increasing over time through the trend line (S405). The base station may initialize RLF information for the terminal when the expected RLF generation value of the terminal does not increase with time (S301). The base station may perform the procedure subsequent to S301 of FIG. 3 .

When the expected RLF generation value of the terminal increases with time, the base station may initialize the RLF counter of the terminal (S406) and perform an RLF avoidance procedure (S407). Next, a pre-handover procedure performed for RLF avoidance is described.

5 is a flowchart illustrating a handover procedure according to an embodiment of the present invention.

Referring to FIG. 5 , the communication system of FIG. 5 may be the same as or similar to the communication system of FIG. 1 . The terminal 500 of FIG. 5 may be the communication nodes 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 of FIG. 1, and the serving base station 510 of FIG. may be the communication nodes 110-1, 110-2, 110-3, 120-1, and 120-2 of FIG. 1, and the target base station 520 of FIG. 5 may be the communication node 110-1, 110-2, 110-3, 120-1, 120-2).

The serving base station 510 may be a base station connected to the terminal 500 . The serving base station 510 may allow the terminal 500 to be handed over to a neighboring base station when an RLF occurrence is expected while in a connected state with the terminal 500 .

The terminal 500 may transmit a measurement report message to the serving base station 510 when the signal strengths of the serving base station 510 and the target base station 520 measured by the terminal 500 satisfy a specific criterion. The serving base station 510 may adjust handover parameters (eg, handover hysteresis (HO), time to trigger (TTT)) values. The serving base station 510 may adjust the time point at which handover occurs by adjusting handover parameters. That is, the serving base station 510 may allow handover to occur in advance by adjusting handover parameters.

For example, the serving base station 510 may adjust the handover hysteresis value and the TTT value small. The serving base station 510 may transmit the adjusted handover hysteresis value and TTT value to the terminal 500 through a measurement control message (S501). The terminal 500 may receive the adjusted hysteresis value and TTT value. The terminal 500 may apply the received handover hysteresis value and TTT value. The terminal 500 may periodically measure RSRP and reference signal received quality (RSRQ) based on reference signals (RS) received from the serving base station 510 and neighboring base stations. The terminal 500 may transmit a measurement report message to the serving base station 510 when the RSRP/RSRQ value of the neighboring base station is higher than the value of the serving base station 510 by a handover hysteresis value or higher and lasts for as long as the TTT time (S502). .

The serving base station 510 may receive a measurement report message from the terminal 500 . When the measurement report message is received from the terminal 500, the serving base station 510 may select a target base station 520 based on the received measurement report message and information collected by the serving base station 510. For example, the serving base station 510 determines signal strength (RSRP), central processing unit (CPU) occupancy, available bandwidth, user preference, and network connection time of each neighboring base station. And it is possible to select the target base station 520 based on the security level (security level) information. Equation 2 represents a handover suitability expected value prediction model.

Referring to Equation 2, the serving base station 510 may calculate expected values of handover suitability for each neighboring base station based on the main factors considered in selecting the target base station 520 . The main factors considered in selecting the target base station 520 may be information included in the measurement report message. That is, the serving base station 510 determines the signal strength, CPU occupancy rate, available bandwidth, preference, network access time, and security level of each base station as independent variables (x- ₁ , x- ₂ , x- ₃ , x- ₄ , x - ₅ , x- ₆ ) can calculate the expected value of handover suitability. Independent variable x ₁ may mean the signal strength of each neighboring base station. The signal strength of each neighboring base station may be transmitted from the terminal 500 to the serving base station 510 . Independent variables x ₂ , x ₃ , x ₅ , and x ₆ may mean CPU occupancy, available bandwidth, network access time, and security level of neighboring base stations, respectively. Information on CPU occupancy, available bandwidth, network access time, and security level of neighboring base stations may be transmitted to the serving base station 510 from neighboring base stations. Independent variable x ₄ may mean user preference. The user preference information may be preference information of the terminal 500 received by the serving base station 510 from the subscriber server. The weights a, b, c, d, e, and f may be constant values for each independent variable (x ₁ , x _2, x _3, x ₄ , x ₅ , x ₆ ). The weights (i.e., a, b, c, d, e, and f) must be determined prior to performing the handoff suitability prediction process. Weights may be determined through machine learning based on accumulated independent variables (x ₁ , x _{2 ,} x _{3 ,} x ₄ , x ₅ , x ₆ ) and handover data. Alternatively, the weight may be determined according to a system operation policy of a network operator. The network operator can adjust the weight information by considering the characteristics of the service according to the policy. That is, the network operator can adjust the weight information according to a service requiring a general handover standard, a service requiring large-scale data transmission, a service requiring an important security level, a base station preferred by a user, and the like. The error term ε is assumed to follow a normal distribution with mean 0 and variance σ ² .

The handover suitability expected value may be calculated in the serving base station 510 or in the handover prediction server. The serving base station 510 may transmit information on independent variables (x ₁ , x _2, x _3, x ₄ , x ₅ , x ₆ ) necessary for calculating the handover suitability expected value to the handover prediction server, and the handover prediction server may receive information necessary for calculating a handover suitability expected value from the serving base station 510. The handover prediction server may calculate a handover suitability expectation value based on the received information. When the handover suitability expected value is calculated in the handover prediction server, the weight of Equation 2 is based on the accumulated independent variables (x ₁ , x _2, x _3, x ₄ , x ₅ , x ₆ ) and handover data. can be determined in the handover prediction server through a machine learning process. The handover prediction server may select a target base station 520 based on the expected value of handover suitability, and may transmit information on the selected target base station 520 to the serving base station 510 . The handover prediction server may be installed inside each base station or installed in a separate device.

The serving base station 510 may select the target base station 520 based on the handover suitability expectation value calculated directly, or may receive information on the selected target base station 520 from the handover prediction server (S503). The serving base station 510 may transmit a handover request message to the target base station 520 (S504). The target base station 520 may receive a handover request message from the serving base station 510, and a handover procedure may be performed to the target base station 520.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable 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 media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the claims below. You will be able to.

Claims (10)

As a method of operating a serving base station supporting handover,
Collecting radio link information between the terminal and the serving base station from a terminal;
determining whether an error has occurred in a radio link with the terminal based on the radio link information;
calculating an expected value when an error occurs in the wireless link when the error does not occur in the wireless link;
supporting handover of the terminal when the expected value is greater than a first reference value;
comparing the expected value with a second reference value smaller than the first reference value when the expected value is greater than the first reference value; and
And if the expected value is greater than the second reference value, initializing the radio link information. The method of claim 1,
The radio link information includes the signal strength level of the serving base station, the number of radio link control (RLC) retransmissions, the time at which a message periodically transmitted from the terminal is not received, and the terminal's physical downlink control channel (PDCCH) block error (BLER) rate) characterized in that it includes at least one of the times exceeding 10%, the operating method of the serving base station. The method of claim 1,
The step of calculating the expected value of the occurrence of the radio link error,
determining weights; and
The wireless A method of operating a serving base station comprising calculating an expected value in which a link error will occur. The method of claim 1,
determining whether the expected value increases if the expected value is greater than the second reference value; and
As a result of determining whether the expected value is increased, if the expected value is increasing, further comprising supporting handover of the terminal, the operating method of the serving base station. The method of claim 4,
As a result of determining whether the expected value increases, if the expected value does not increase, further comprising initializing the radio link information, the operating method of the serving base station. The method of claim 4,
Further comprising increasing a counter indicating the number of times an occurrence prediction procedure is performed after calculating an expected value of the occurrence of the radio link error,
The step of determining whether the expected value increases,
comparing the counter with a third reference value;
initializing the radio link information when the counter is greater than the third reference value;
checking a trend line of the expected value when the counter is greater than the third reference value; and
And determining whether the expected value is increasing over time using the trend line. The method of claim 1,
The step of supporting the handover,
calculating handover compatibility of neighboring base stations based on the radio link information;
selecting a target base station from among the neighboring base stations based on the calculated handover suitability; and
A method of operating a serving base station comprising the step of supporting handover of the terminal to the target base station. The method of claim 7,
The handover suitability is determined by the reference signal received power of each of the neighboring base stations, each central processing unit (CPU) occupancy rate, each available bandwidth, and each user preference of the neighboring base stations. ), each network connection time (network connection time) and each security level (security level) characterized in that the calculation based on at least one of the information, the operating method of the serving base station. As a serving base station,
processor;
a memory that communicates electronically with the processor; and
Includes instructions stored in the memory;
When the instructions are executed by the processor, the instructions cause the serving base station to:
Collecting radio link information between the terminal and the serving base station from the terminal;
determining whether a radio link error with the terminal has occurred based on the radio link information;
when the radio link error does not occur, calculating an expected value of the radio link error occurrence;
When the expected value is greater than a first reference value, supporting handover of the terminal;
if the expected value is greater than the first reference value, comparing the expected value with a second reference value less than the first reference value; and
If the expected value is greater than the second reference value, the serving base station operates to cause initialization of the radio link information. The method of claim 9,
When calculating the expected value of the radio link error, the commands are the serving base station,
determine weights; and
The wireless A serving base station that is operative to cause calculating an expectation that a link error will occur.

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