KR20230037392A - Method and heterogeneous wireless interworking network system for dynamic intelligent frequency operation - Google Patents

Abstract

The present invention is an operating method of a first base station using a first service frequency for 5G services in an environment where a plurality of cells using different wireless frequencies are overlapped. The method comprises the steps of: confirming traffic load information from a second base station providing the 5G service and the LTE service through a second service frequency different from the first service frequency; based on 5G traffic information having 5G traffic information of the first base station and 5G traffic information of the second base station added thereto, determining whether the frequency of the second base station is shared by a dynamic spectrum sharing (DSS) method or a static spectrum sharing (SSS); and transmitting the determined information to the second base station.

Description

Dynamic intelligent frequency operation method and heterogeneous wireless network interworking system

The present invention relates to a dynamic intelligent frequency management method and a heterogeneous network wireless network interworking system.

Most 5G networks are built using high-bandwidth frequencies (eg, 3.5GHz, 28GHz, etc.) with a wider bandwidth than LTE (Long Term Evolution). In particular, when initially establishing a 5G network, 5G is complemented by a narrow 5G coverage by adopting a NSA (Non-Stand Alone) structure in which 5G is linked with existing LTE and dual connectivity. In addition, when a Stand Alone (SA) network is built to provide various vertical services, voice services are provided through VoNR ((Voice over New Radio) or Vo5G (Voice over 5G) based IMS (IP Multimedia Subsystem). For this, a nationwide network level of dense coverage is required.

However, with existing 5G frequencies (eg, 3.5 GHz frequencies), it is difficult to secure LTE-level coverage using low-band frequencies, especially indoor and outdoor coverage in a short period of time. Therefore, there is a limit to the increase in 5G offloading, and the investment cost of 5G base stations also increases rapidly.

On the other hand, merge transmission between several 5G frequencies with different frequencies is a means to expand the effective coverage of the 5G SA network and increase transmission speed. However, in an actual complex wireless network situation, although the applied wireless technology, radio wave characteristics, bandwidth, construction coverage, wireless equipment structure, wireless terminal specifications, etc. are different for each frequency, the access control of the wireless base station considering these is not designed efficiently. .

In addition, access control of a radio base station for merging multiple NR frequencies in consideration of sharing between NR frequencies and LTE frequencies, which are heterogeneous radio technologies, has not been conventionally provided.

The tasks to be solved are how to share and use LTE frequencies for LTE subscribers and 5G subscribers to operate 5G services, how to combine and use LTE frequencies and NR frequencies, which are heterogeneous wireless technologies, and considering the characteristics of 5G terminals with various specifications. It is to provide a method and system for controlling access of a base station by doing so.

According to one feature, a method of operating a first base station using a first service frequency for a 5G service in an environment in which a plurality of cells using different radio frequencies overlap, and a second service different from the first service frequency Checking traffic load information from a second base station providing the 5G service and LTE service through frequency, based on 5G traffic information obtained by adding 5G traffic information of the first base station and 5G traffic information of the second base station Determining whether to share the frequency of the second base station using a dynamic spectrum sharing (DSS) method or a static spectrum sharing (SSS) method, and transmitting the determined information to the second base station.

In the determining step, based on the traffic load information, if the load ratio of the 5G service subscribing terminal to the load of the LTE service subscribing terminal connected to the second base station is less than a reference ratio, frequency sharing is determined as DSS, If the ratio is greater than the reference ratio, the frequency sharing may be determined as SSS.

The determining step, based on the traffic load information, if the ratio of the LTE traffic load to the 5G traffic load of the second base station is less than a reference ratio, select frequency sharing as DSS, and if greater than the reference ratio, the frequency You can select Share as SSS.

The transmitting may include a DSS operation indicator or an SSS operation indicator.

In the transmitting step, if the SSS is determined, information on the bandwidth allocated to the 5G service and the bandwidth allocated to the LTE service may be transmitted.

According to another feature, a method of operating a first base station using a first service frequency in an environment in which a plurality of cells using different radio frequencies overlap, wherein the second service frequency is different from the first service frequency. Receiving radio channel quality information obtained from a second base station providing 5G service and LTE service, determining the primary cell of the terminal as the first service frequency or the second service frequency based on the radio channel quality information and instructing a terminal connected to the second base station or a terminal connected to the first base station to change the primary cell according to the determined information.

In the determining step, if the radio channel quality of the second service frequency is less than or equal to the reference value or the difference between the radio channel quality of the first service frequency and the radio channel quality of the second service frequency is greater than or equal to the reference value, the terminal's price A head cell may be determined as the first service frequency.

In the determining step, when the terminal does not support carrier aggregation for the first service frequency, a primary cell of the terminal may be determined as the first service frequency.

In the determining step, if the radio channel quality of the first service frequency is less than or equal to the reference value or the difference between the radio channel quality of the second service frequency and the radio channel quality of the first service frequency is greater than or equal to the reference value, the terminal's price A head cell may be determined as the second service frequency.

In the determining step, if the total traffic load of the second service frequency is greater than or equal to a reference value, it may be determined to stop carrier aggregation of the first service frequency for the terminal.

In the determining step, if the received signal strength of positioning satellites or the number of available satellites measured by the terminal is less than or equal to a reference value, the primary cell of the terminal may be determined as the second service frequency.

According to another feature, a method of operating a first base station using a first service frequency in an environment in which a plurality of cells using different radio frequencies overlap, comprising: checking network slice information of a terminal; Selecting a primary cell of the terminal from among the first service frequency or a second service frequency different from the first service frequency based on network slice information, and transmitting the selected primary cell indicator to the terminal. do.

In the selecting, when the network slice information indicates a service for which coverage is important, the second service frequency having a relatively wide coverage may be determined as the primary cell.

In the determining step, when the network slice information indicates a service for which speed is important or a service that requires a minimized delay, the first service frequency having a wide bandwidth may be determined as a primary cell.

In the determining step, when the network slice information indicates services other than a service in which bandwidth is important, frequency carrier aggregation may be turned off.

According to another feature, a heterogeneous wireless network interworking system includes a first base station using a first service frequency, and a second base station using a second service frequency different from the first service frequency, wherein the first base station , Based on the information received from the second base station through inter-base station communication, at least one of a frequency sharing scheme, a primary cell, and a carrier aggregation of a terminal is determined, and the second base station operates in the determined manner. ask for

The first base station may selectively determine the frequency sharing method of the second base station as DSS or SSS based on real-time traffic load information acquired from the second base station.

The first base station may determine a primary cell based on radio channel quality or traffic load according to whether a terminal connected to the second base station supports carrier aggregation.

The first base station may determine at least one of a primary cell or carrier aggregation on/off based on a network slicing ID being used by the terminal.

The first base station may request the second base station through a cell resource coordination procedure between base stations and a base station configuration update procedure.

According to the embodiment, in order to efficiently use frequency sharing and NR frequency aggregation between heterogeneous wireless technologies, it is possible to intelligently operate a wireless base station and a wireless terminal in consideration of related information affecting a corresponding function.

In addition, it is possible to efficiently utilize low-band frequency resources and expand indoor and outdoor coverage through access control procedures and devices for frequency sharing between 5G and LTE, which are heterogeneous wireless networks, and intelligent operation of NR CA.

In addition, telecommunication companies can utilize existing LTE base station equipment well-established throughout the country as a 5G nationwide network in a short period of time, enabling significant savings in wireless network construction and operation costs.

1 illustrates a cell environment of a mobile communication system providing 5G service according to an embodiment.
2 is another exemplary diagram of a cell environment according to an embodiment.
3A is a diagram for explaining SSS applied to an embodiment.
3B is a diagram for explaining a DSS applied to an embodiment.
4 is a flowchart illustrating operations of a base station for controlling frequency operation and controlling access of a terminal to a base station according to an embodiment.
5 is a series of flowcharts illustrating a method of selectively determining a frequency sharing scheme according to an embodiment.
6 is a state change diagram of a terminal according to an embodiment.
7 is a state change diagram of a terminal according to another embodiment.
8 shows an NR primary cell selection procedure according to an embodiment.
9 illustrates an NR primary cell selection procedure according to another embodiment.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

In addition, terms such as “…unit”, “…unit”, and “…module” described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. can

Devices described in the present invention are composed of hardware including at least one processor, memory device, communication device, and the like, and a program to be executed in combination with the hardware is stored in a designated place. The hardware has the configuration and capability to implement the method of the present invention. The program includes instructions implementing the operating method of the present invention described with reference to the drawings, and implements the present invention in combination with hardware such as a processor and a memory device.

In this specification, "transmission or provision" may include not only direct transmission or provision, but also indirect transmission or provision through another device or by using a detour path.

Expressions written in the singular in this specification may be interpreted in the singular or plural unless an explicit expression such as “one” or “single” is used.

In this specification, like reference numerals refer to like elements, regardless of drawing, and "and/or" includes each and every combination of one or more of the recited elements.

In this specification, terms including ordinal numbers such as first and second may be used to describe various components, but the components are not 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 disclosure.

In the flowcharts described herein with reference to the drawings, the order of operations may be changed, several operations may be merged, certain operations may be divided, and certain operations may not be performed.

In the specification, a terminal/user equipment accesses a base station of an access network/radio access network (RAN) and uses network functions (NFs) of a core network. Here, the base station may include eNB, gNB, AP, etc. according to the access network. The terminal may be a terminal of various types and purposes, such as a portable terminal, an IoT terminal, a vehicle terminal, a display terminal, a broadcasting terminal, and a game terminal. Devices constituting the network may be implemented as hardware, software, or a combination of hardware and software.

Embodiments of the present invention are 3GPP such as 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), LTE-A, 3GPP2, Institute of Electrical and Electronics Engineers (IEEE) system, Study on Architecture for Next Generation System (FS_NextGen) It may be supported by standard documents related to at least one of the 5G systems. That is, among the embodiments of the present invention, steps or parts not described to clearly reveal the technical spirit of the present invention may be supported by the above document. In addition, all terms disclosed in this document can be explained by the standard document.

The LTE core network includes MME (Mobility Management Entity), SGW (Serving Gateway), PGW (Packet data network Gateway), HSS (Home Subscriber Server), PCRF (Policy and Charging Control Function), etc., and is used in the LTE communication system Concepts of communication technology and network device configurations to be used may be referred to in the embodiments of the present invention.

The 5G core network is AMF (Access and Mobility Function), SMF (Session Management Function), UPF (User Plane Function), UDM (User Data Management), UDR (Unified Data Repository), PCF (Policy Control Function), SPR (Subscriber) Profile Repository) and the like, and concepts of communication technology and network device configurations used in the 5G communication system may be referred to in an embodiment of the present invention.

5G (NR) radio access network, LTE radio access network, SA (Standalone) network, dynamic spectrum sharing (DSS), static spectrum sharing (SSS), frequency refarming, Base station interworking interface, Xn interface/protocol, MR-DC (Multi-RAT Dual Connectivity), carrier aggregation (CA) transmission and control, radio resource scheduling, cell management and load management, radio access control, user and control plane Configurations and concepts related to interface, 5G protocol, network slicing, open radio access network (Open RAN), network multi-vendor interoperability (MVI), and voice over NR (VoNR) of the present invention Reference may be made to the examples.

1 illustrates a cell environment of a mobile communication system providing 5G service according to an embodiment, FIG. 2 is another exemplary diagram of a cell environment according to an embodiment, and FIG. 3A is a diagram illustrating SSS applied to the embodiment. 3B is a diagram illustrating a DSS applied to an embodiment, and FIG. 4 is a flowchart illustrating operations of a base station for frequency operation control and access control of a terminal to a base station according to an embodiment.

Referring to FIG. 1, a mobile communication system providing 5G service, that is, a 5G system is a standalone (SA) system, and includes a terminal 100, at least one 5G base station (gNB) 200 providing 5G service, and 5G It includes at least one Long Term Evolution (LTE) base station (eNB) 300 and a 5G core network 400 providing services.

The terminal 100 is a terminal subscribing to a 5G service and can access the 5G base station 200 and the LTE base station 300 providing the 5G service.

The 5G base station 200 and the LTE base station 300 may communicate using a predetermined interworking interface for exchange and interworking of necessary messages and information.

According to one embodiment, the 5G base station 200 and the LTE base station 300 may communicate using an Xn interface supporting a Multi-RAT Dual Connectivity (MR-DC) protocol.

According to another embodiment, when the manufacturer of the 5G base station 200 and the LTE base station 300 are the same, communication may be performed using an interface developed by the manufacturer itself.

The 5G base station 200 and the LTE base station 300 may communicate with the 5G core network 400 using a Next Generation (NG) interface.

According to the embodiment, the 5G base station 200 and the LTE base station 300 may be physically separated into a digital unit (DU) and a radio unit (RU). DUs are usually located in central offices and are connected to the 5G core network 400 to process wireless digital signals. The RU is physically separated from the DU and is located at the cell site, converts and amplifies the radio signal received from the terminal 100 into a digital signal, transfers it to the DU, and converts and amplifies the digital signal received from the DU into a radio signal so that the terminal ( 100). When the 5G base station 200 and the LTE base station 300 are separated into RUs and DUs, interworking between base stations is performed between the DUs.

Referring to FIG. 1 , an environment in which a plurality of cells using different radio frequencies, that is, a first service frequency and a second service frequency are overlapped is shown. The first service frequency and the second service frequency have different frequencies, but are used for 5G service. The first service frequency and the second service frequency may include a New Radio (NR) frequency (f _N ) and a low-band (hereinafter collectively referred to as 'LB') frequency (f _L ).

The 5G base station 200 serves a New Radio (NR) frequency f _N for 5G service. Hereinafter, in this specification, the 5G base station 200 will be referred to as the NR base station 200. Since the coverage of the NR frequency (f _N ) is relatively small, it is necessary to share and use frequencies of other radio technologies for 5G subscribers to compensate for this. Low-band LTE frequencies (e.g., 1.8 GHz, 900 MHz, etc.), which have nationwide coverage and relatively wide coverage due to excellent indoor and outdoor propagation characteristics, can be used as shared frequencies that can be operated at low cost.

According to an embodiment, some or all of the LTE frequencies are used for 5G subscribers. Therefore, the LTE base station 300 shares and uses the LTE frequency as a service frequency for the 5G subscriber and the LTE subscriber through one of the DSS and SSS schemes. That is, the LTE base station 300 provides LTE frequencies for LTE subscriber terminals (not shown) and low-band (hereinafter referred to as 'LB') frequencies f _L for 5G services by servicing , can simultaneously perform the role of the NR base station as well as the role of the original LTE base station.

Hereinafter, the LTE base station 300 will be referred to as the LB base station 300 in this specification.

Since the LTE frequency using the low-band frequency can use 1.8GHz, 900MHz, etc., the 5G frequency served by the LB base station 300, that is, the LB frequency (f _L ) also uses 1.8GHz, 900MHz, etc. The NR frequency (f _N ), which is a high-bandwidth frequency capable of wide bandwidth compared to LTE, may use 3.5 GHz, 28 GHz, or the like.

According to the embodiment, as an example of a typical frequency allocation, f _L may be set to 1.8 GHz and f _N may be set to a band frequency of 3.5 GHz. Of course, the actual service available 5G and LTE frequencies may increase depending on the construction area and radio wave environment, and various embodiments can be applied. The LB base station 300 serves a 5G frequency for 5G subscriber terminals, that is, an LB frequency (f _N ) and an LTE frequency for LTE subscriber terminals, and their frequency coverages have almost similar sizes. On the other hand, the NR base station 200 serves an NR frequency f _N having a smaller coverage than those of the LB base station 300 .

The terminal 100 located in an arbitrary area can use the 5G service by being connected to the 5G core network 400 through the NR base station 200 and the LB base station 300.

At this time, the coverage provided by the NR base station 200 and the coverage provided by the LB base station 300 are distinguished through a cell ID.

By sharing existing low-band LTE frequencies (e.g., 1.8GHz, 900MHz, etc.) with excellent propagation characteristics and wireless base stations serving these LTE frequencies, they are dynamically or statically allocated to 5G service and LTE service. If used, it may be possible to secure nationwide 5G coverage in a short period of time.

Referring to FIG. 2 , a terminal 100 located in a rural area/outside where an NR base station 200 is not yet installed is connected to the LB base station 300 serving an LB frequency and uses a 5G service. In addition, the terminal 100 located in a region where the NR base station 200 is spread, such as a large city or an in-building, accesses the NR base station 200 and uses the 5G service. At this time, since the large city or in-building area is also covered by the LB base station 300, the 5G service can be provided to the terminal 100 through carrier aggregation (hereinafter referred to as 'CA') between the NR frequency and the LB frequency.

As such, it is possible to provide service even in indoor or outlying areas where existing 5G radio waves, which are relatively high-bandwidth frequencies, cannot reach by using LTE infrastructure pre-established through LTE frequency sharing. In particular, in order to provide seamless voice service based on VoNR (Voice over New Radio) instead of VoLTE (Voice over LTE) serviced through the existing LTE network in the 5G SA network, the coverage hole must be minimized, and low-band frequencies can solve this problem. .

In this cell environment, the NR base station 200 and the LB base station 300 can adjust radio resource allocation through an E-UTRA-NR cell resource coordination procedure. The subject of radio resource allocation adjustment may be the NR base station 200 or the LB base station 300, but in an embodiment of the present invention, the NR base station 200 will be described. In addition, the NR base station 200 and the LB base station 300 are required to interoperate through an Xn interface-based NG-RAN (Radio access network) node configuration update request / response procedure. Level configuration data can be exchanged.

According to an embodiment, a frequency sharing technology and a frequency aggregation (CA) technology are used in a cell environment as shown in FIGS. . In order to efficiently use frequency sharing technology and frequency aggregation technology between heterogeneous wireless technologies, intelligent operation considering related information affecting these technologies is required.

In this specification, it is assumed that the basic primary cell frequency of the terminal 100 is set to the NR frequency (f _N ) cell, and the bandwidth of f _N is significantly greater than the f _L bandwidth.

First, the frequency sharing technology will be described as follows.

The LB base station 300 uses a specific frequency, ie, LTE frequency, for both LTE service and 5G service, ie, shares the LTE frequency for different heterogeneous services. Frequency sharing technology allows LTE frequency to be divided and used for LTE subscribers and 5G subscribers through time, frequency, or a method combining time and frequency.

As such, when sharing the same frequency, the LTE frequency may be refarmed. As a method for frequency refarming, Dynamic Spectrum Sharing (hereinafter collectively referred to as 'DSS') and Static Spectrum Sharing (hereinafter collectively referred to as 'SSS') may be used.

Here, the SSS method is a method of fixedly allocating a frequency f L for an LTE service and a frequency f _L for a 5G service by a preset area size regardless of time over the entire frequency domain, as shown in FIG. 3A. That is, each frequency domain is fixedly set in advance, and the size of the frequency domain is manually changed by an operator. Therefore, in the case of the SSS method, in order to change some or all of the existing LTE frequencies to 5G uses, frequency refarming, which allocates LTE frequencies to 5G uses, must be preceded.

On the other hand, as shown in FIG. 3B, the DSS method allocates a frequency for LTE service and a frequency f _L for 5G service by changing over time. DSS automatically changes the frequency bandwidth to be allocated for LTE and 5G services by occupied traffic and access terminals. In addition, in DSS, it is possible to dynamically allocate and use LTE frequencies and 5G frequencies in real time at a specific period (eg, 1 ms) for the entire frequency bandwidth.

While SSS is capable of simple operation and is easy to protect a certain level of 5G or LTE subscribers, it has a limitation in that it is difficult to flexibly respond to changes in 5G/LTE traffic within a cell and changes in supported terminals (subscribers). Therefore, selective operation of SSS and DSS is required for the frequency sharing method of the LB base station 300 according to changes in 5G/LTE traffic and support terminals (subscribers) within the cell. Next, for frequency aggregation (CA) technology The explanation is as follows.

The terminal 100 first accesses and connects to a primary cell (PCell), and based on this, performs a CA procedure by additionally connecting a secondary cell (SCell).

The 5G network is built with a medium-band frequency (e.g., 3.5 GHz) that has relatively narrow coverage compared to LTE, but when a low-band frequency (e.g., 1.8 GHz) is operated as DSS or SSS, primary Cell operation becomes important.

In particular, in an area where 3.5 GHz has a weak electric field, such as indoors, it is advantageous to first connect to a low-band frequency. Accordingly, the primary cell may be selectively applied from among the NR base station 200 and the LTE base station 300 according to radio channel quality.

In addition, since the CA procedure may be provided for the terminal 100 supporting CA, whether or not CA may be determined according to radio channel quality and terminal type.

In addition, unlike the LTE network, the 5G SA network can support various types of network slicing, which is distinguished by a unique network slice identifier for each service provided. For example, eMBB (Enhanced Mobile Broadband) slice, URLLC (ultra-reliable low-latency communications) slice, mMTC (massive machine type communications) or mIoT (Mobile Internet of Things) slice, V2X (Vehicle-to-Everything) slice. this is possible

In this way, services mapped to different network slices should be provided with an optimal wireless connection suitable for the characteristics of the corresponding network slice so that the service can be provided more smoothly. Therefore, it is necessary to determine whether the primary cell and CA of the terminal 100 are taken into consideration together with the network slice information to which the terminal 100 is connected.

Basically, the terminal 100 operates in SSS mode. In order to selectively operate DSS and SSS, the terminal 100 must support DSS. However, since the terminal 100 needs to be changed to support DSS, the terminal 100 supporting DSS and the terminal 100 not supporting DSS may be mixed.

Also, the CA function may or may not be supported by the terminal 100 . At this time, since CA is a combination of NR frequency and LB frequency, it is commonly referred to as NR CA. Considering this, there may be three types according to the communication modem specifications used by the terminal 100 in the 5G SA network. Same as 1.

terminal classification explanation UE _A Supports both DSS and NR CA _UEB DSS supported but NR CA not supported UE _C Both DAA and NR CA are not supported

According to Table 1, various types of terminals can be serviced according to the communication modem specifications used by the terminal, that is, the UE, in the 5G SA network.

UE _A is a 5G SA terminal and does not support both DSS and NR CA. UE _B is a 5G SA terminal and supports DSS but does not support NR CA. UE _C is a 5G SA terminal and supports both DSS and NR CA.

In the cell environment as described above, the NR base station 200 intelligently controls frequency operation such as frequency sharing/merging and base station access control of the terminal 100 in consideration of specifications, radio quality, and traffic conditions of the terminal 100 The configuration and operation to be described will be described for each embodiment. Since the NR base station 200 is the main base station for 5G service subscribers, the NR base station 200 is the subject of the control procedure, but the LB base station 300 may control it according to the embodiment.

The operation of the base station for frequency operation control and terminal access control to the base station will be described as shown in FIG. 4 .

Referring to FIG. 4, the NR base station 200 receives traffic load information, radio channel quality information, and terminal information from the LB base station 300, and among the network slice information that the terminal 100 is accessing from the core network 400 At least one is received (S101).

At this time, each of the NR base station 200 and the LB base station 300 may periodically collect necessary information with the terminal 100, or may collect it at the request of the terminal 100 or the base stations 200 and 300. . The NR base station 200 and the LB base station 300 exchange collected information through messages on the Xn interface, and exchange network slice information through messages on the NG (or N2) interface. At this time, in S101, an E-UTRA-NR Cell Resource Coordination procedure may be performed.

At this time, network slice information for the terminal 100 accessing both the NR base station 200 and the LB base station 300 as well as the terminal 100 accessing only the LB base station 300 or accessing only the NR base station 200 is The NR base station 200 may obtain it from the core network 400 or may acquire it from the LB base station 300 through a -UTRA-NR cell resource adjustment procedure. Of course, the LB base station 300 can acquire from the core network 300 and provide it to the NR base station 200.

The NR base station 200 determines at least one of a frequency sharing method, NR primary cell determination, and NR CA on/off based on the information received in S101 (S102). According to one embodiment, in S102, the NR base station 200 may select one of DSS and SSS based on real-time cell environment information received in S101, that is, traffic load information. According to another embodiment, in S102, the NR base station 200 selects a price between the NR cell and the LB cell based on the radio channel quality or traffic load measured by the terminal 100 and whether the terminal 100 supports NR CA. After determining the head cell, whether to operate the NR CA may be determined based on the total traffic load of the LB cell for the terminal 100 supporting the NR CA.

According to another embodiment, the NR base station 200 determines a primary cell from among the NR cell and the LB cell based on the strength of the GPS reception signal of the terminal 100 or the number of available satellites received from the LB base station 300 in step S102. can

According to another embodiment, a primary cell is determined from among the NR cell and the LB cell based on the network slice ID received from the LB base station 300 or the network slice ID confirmed by the core network 400 in step S102, and the NR CA on You can decide on/off.

The NR base station 200 transmits the information determined in S102 to the LB base station 300 and instructs the LB base station 300 and the terminal 100 to apply (S103). At this time, in S103, a radio access network (NG-RAN) node configuration update (NG-RAN node configuration update) request/response procedure based on the Xn interface may be performed.

At this time, the operation that requires setting in the terminal 100 is performed by the terminal 100 and the NR base station 200 or the LB base station 300 through a Radio Resource Control (RRC) message. For example, the NR base station 200 may request the terminal 100 within a specific cell to set/change the NR primary cell to the NR base station 200 or the LB base station 300.

Now, various embodiments of S102 will be described as follows.

First, according to one embodiment, the frequency sharing method of the LB base station 300 may be selectively operated as DSS or SSS based on a real-time cell environment, that is, traffic load. In the past, telecommunication operators have fixed the frequency sharing method of base stations to DSS or SSS, but it is difficult to predict the traffic load of 5G subscribers in a specific cell, with current 5G subscribers accounting for about 30%. There is a problem that is difficult to predict whether it will be good in terms of efficiency. Therefore, the frequency sharing method of the LB base station 300 can be selectively operated from SSS and DSS based on the real-time cell environment, that is, the traffic load of the 5G terminal 100.

SSS, in which part of the frequency bandwidth of the LB base station 300 is allocated to LB frequencies and the rest to LTE frequencies, has no control signal overhead compared to DSS, and thus has a frequency efficiency of up to 30% higher. On the other hand, DSS has the advantage of being able to flexibly and dynamically allocate resources to LTE frequencies and LB frequencies according to traffic conditions. Therefore, the NR base station 200 changes the LB base station 300 to SSS or DSS according to the ratio of the LTE terminal and the 5G terminal 100 and the traffic load in a specific cell (or cell group) and operates the efficiency of network operation. can be higher. Here, the change period can be set by the operator. The 5G traffic is the sum of the traffic received from the LB base station 300 and the traffic calculated from the NR traffic 100.

5 is a series of flowcharts illustrating a method of selectively determining a frequency sharing scheme according to an embodiment.

Referring to FIG. 5, the NR base station 200 connected to the LB base station 300 through the Xn interface (S201) sends an E-UTRA-NR Cell Resource Coordination Request message to the LB base station 300. Transmit (SS02).

The LB base station 300 checks the cell traffic load information (S203), includes it in an E-UTRA-NR Cell Resource Coordination Response (E-UTRA) message, and transmits it to the NR base station 200 (S204).

At this time, the cell traffic load information is included in the form of additional information (IE) in addition to the information originally included in the inter-cell resource negotiation response message, and may be shown in Table 1 below.

division explanation data traffic load Divided into DL, UL, DU+UL Data traffic load per RAT Divided into NR and LTE Load by terminal type Classified into LTE and 5G terminals (UE _A , UE _B , and UE _C terminals) Indicator of whether the terminal supports the NR CA function Divided into support and non-support

Referring to Table 1, the LB base station 300 may include cell traffic load information classified into data traffic load, data traffic load for each RAT, and load for each terminal type. In addition, the load for each terminal type includes load information for each LTE terminal and 5G terminal, but the 5G terminal may be displayed separately for each terminal type as shown in Table 1. At this time, the terminal type may additionally include an indicator indicating whether the NR CA function is supported.

The NR base station 200 determines whether to operate the frequency serviced by the LB base station 300 as DSS or SSS based on the additional information (IE) received in step S204, that is, cell traffic load information.

The NR base station 200 determines whether a ratio of 5G traffic to LTE traffic is greater than a threshold based on cell traffic information (S205).

)이 기준치(예, 150%)보다 작은지 판단하거나 또는 표 2의 RAT 별 데이터 트래픽 부하에 기초하여 LTE 트래픽 부하 대비 5G 트래픽 부하 비율(

)이 기준치(예, 200%)보다 작은지 판단할 수 있다. 트래픽 부하는 트래픽 버퍼로도 계산 가능하다. 여기서, 5G 단말 부하는 LB 기지국(300)에서 획득한 단말 부하와 NR 기지국(200)에서 획득한 단말 부하를 합산한 값이고, 5G 트래픽 부하는 LB 기지국(300)에서 획득한 트래픽 부하와 NR 기지국(200)에서 획득한 트래픽 부하를 합산한 값이다.At this time, the NR base station 200 calculates the ratio of the 5G terminal to the LTE terminal among the terminals in the cell serviced by the LB base station 300 based on the load for each terminal type in Table 2 (

) is smaller than the reference value (eg, 150%), or based on the data traffic load for each RAT in Table 2, the ratio of 5G traffic load to LTE traffic load (

) is smaller than the reference value (eg, 200%). Traffic load can also be calculated as a traffic buffer. Here, the 5G terminal load is the sum of the terminal load obtained from the LB base station 300 and the terminal load obtained from the NR base station 200, and the 5G traffic load is the traffic load obtained from the LB base station 300 and the NR base station It is the sum of the traffic loads obtained in (200).

The NR base station 200 determines the DSS if the ratio of the 5G traffic load to the LTE traffic load is not greater than the threshold value in S205, that is, if it is small (S206). In this case, since the LTE traffic is greater than the 5G traffic, a DSS for adjusting the LTE frequency according to the traffic load ratio is determined to be advantageous to the LTE service subscriber rather than the 5G service subscriber. That is, the f _L frequency is determined by the DSS method.

On the other hand, the NR base station 200 determines the SSS when the ratio of the 5G traffic load to the LTE traffic load is greater than the threshold value in S205 (S207). Here, the traffic load can also be calculated as a traffic buffer. In this case, since 5G traffic dominates LTE traffic, SSS is determined so that 5G service subscribers can be served first. Of course, DSS also allocates frequencies according to traffic, so if there is a lot of 5G traffic, more 5G frequencies (f _L ) can be allocated than LTE frequencies, but 5G frequencies ( f _L ) can determine the SSS to allocate. If 5G traffic is dominant over LTE traffic, the ratio of the LB frequency (f _L ) bandwidth can be forcibly set to be large by operating SSS rather than DSS so that the LB base station 300 can accommodate the terminal 100.

The NR base station 200 may allocate all or part of the bandwidth of the LTE frequency to NR-only, ie, LB (f _L ) frequency (S208). When the entire bandwidth of the LTE frequency is used for NR purposes, it is the same as NR (5G) refarming. That is, SS of NR 100% is the same as NR refarming.

The NR base station 200 generates base station configuration update information including the DSS indicator according to the decision in S206 or the SSS indicator according to the determination in S207 and the frequency allocation information allocated in S208 (S209).

The NR base station 200 transmits an NR-RAN node configuration update message including the base station configuration update information generated in S209 to the LB base station 300 (S210).

The LB base station 300 updates the configuration of the base station according to the DSS operation indicator or SSS operation indicator and frequency allocation information received in step S210 (S211). When the SSS indicator is included, frequency allocation information is included, which includes a bandwidth allocation ratio between the LB frequency (f _L ) and the LTE frequency.

After updating the base station configuration (S211), the LB base station 300 transmits an NR-RAN node configuration acknowledge message to the NR base station 200 (S212).

Next, according to the embodiment, the primary cell is selectively connected from the NR base station 200 or the LB base station 300 based on whether the terminal 100 supports NR CA and the radio channel quality measured by the terminal 100 method can be operated. According to the embodiment, a base station serving a frequency whose radio quality measured by the terminals 100 is higher than the threshold is changed to a primary cell, and when the traffic load of the LB base station 300 is equal to or greater than the reference value, access to the LB base station 300 One NR CA function supporting terminal 100 causes the NR CA function to be stopped.

According to the embodiment, it is assumed that 8 GHz DSS is supported, and for convenience, 3.5 GHz may be mapped to f _N and 1.8 GHz may be mapped to f _L , respectively.

6 is a state change diagram of a terminal according to an embodiment.

Referring to FIG. 6 , state changes when the primary cell of the terminal 100 is the NR base station 200 are shown. In this case, the terminal 100 may be located in the coverage of the NR base station 200. Of course, the coverage of the NR base station 200 and the coverage of the LB base station 300. In this case, since the frequency of the NR base station 200 is the basic frequency, it can be set as the primary cell.

When the terminal 100 supports the NR CA function, when the LB frequency is available, that is, when the radio quality is good, the LB base station 300 may be added as a secondary cell and transition to the NR CA mode. If the radio quality of the LB frequency is poor, the connection with the LB base station 300 may be released and transition to the NR frequency mode may be performed.

When the terminal 100 does not support the NR CA function, the terminal 100 may access either the NR base station 200 or the LB base station 300 as a primary cell. If the LB frequency measured by the terminal 100 is available to the terminal 100, that is, if the radio quality of the LB frequency is superior to the radio quality of the NR frequency, the terminal 100 disconnects from the NR base station 200 Then, through a cell reselection procedure, the LB base station 300 can be connected to the primary cell and transition to the LB frequency mode. In this state, if the radio quality of the NR frequency is much better than the radio quality of the LB frequency, again, the terminal 100 releases the access to the LB base station 300 and uses the NR base station 200 through a cell reselection procedure. It can transition to the NR frequency mode by accessing the primary cell.

When VoLTE is started in the NR frequency mode or the LB frequency mode, the terminal 100 accesses the LTE frequency of the LB base station 300 and transitions to the LTE mode, and when VoLTE ends, again, the NR base station 200 is primed. It can be set to the head cell to transition to the NR frequency mode.

7 is a state change diagram of a terminal according to another embodiment.

Referring to FIG. 7 , state changes when the primary cell of the terminal 100 is the LB base station 300 are shown. In this case, when the terminal 100 performs initial network access, such as powering on outside the coverage of the NR base station 200, it connects to the LB base station 300 as a primary cell and is in the LB frequency mode.

When the terminal 100 supporting the NR CA function moves and the NR frequency is available, that is, when the radio quality of the NR frequency becomes good, the NR base station 200 can be added as a secondary cell to transition to the NR CA mode. In this state, when the terminal 100 moves and the radio quality of the NR frequency deteriorates, the connection to the NR base station 200 may be released to transition to the LB frequency mode.

In the case of the terminal 100 that does not support the NR CA function, if the terminal 100 moves and the NR frequency is available, that is, when the radio quality of the NR frequency is relatively superior to the radio quality of the LB frequency, cell reselection Through a procedure, the NR base station 200 can be changed to a primary cell, accessed, and transitioned to the NR frequency mode. In addition, when the terminal 100 moves in the NR frequency mode and the radio quality of the NR frequency is lower than that of the LB frequency, the LB base station 300 is changed to a primary cell through a cell reselection procedure and connected to the LB frequency mode can be transitioned to

When VoLTE is started in the NR frequency mode or the LB frequency mode, the terminal 100 accesses the LTE frequency of the LB base station 300 and transitions to the LTE mode, and when VoLTE ends, again, the NR base station 200 is primed. It can be set to the head cell to transition to the NR frequency mode.

6 and 7, the state change of the terminal 100 may be made according to trigger determination through comparison of channel quality (eg, RSRP, etc.) of a serving cell and a neighboring cell or comparison with an absolute reference value.

8 shows an NR primary cell selection procedure according to an embodiment.

Referring to FIG. 8, the NR base station 200 connected to the LB base station 300 through the Xn interface (S301) sends an E-UTRA-NR Cell Resource Coordination Request message to the LB base station 300. Transmit (S302).

The LB base station 300 may receive terminal measurement information measured by the terminal 100 from the terminal 100 through a terminal measurement information request and response procedure. The terminal measurement information may include radio channel quality measurement information of the NR frequency cell and the LB frequency cell measured by the terminal 100 . In this case, the NR base station 200 may or may not be the primary cell of the terminal 100.

The LB base station 300 checks the terminal type information, the terminal measurement information, and the entire cell traffic load information (S304), and transmits an E-UTRA-NR Cell Resource Coordination Response message including the same to the NR base station (S304). 200) (S30).

At this time, the message transmitted in S30 includes the radio channel quality parameters (P, Q) of the terminal 100 and the entire cell traffic load (μ) of f _L of the LB base station 300, and the terminal 100 measures The received signal strength (σ) of positioning satellites and the number of available satellites (η) may be further included.

The NR base station 200 determines the primary cell frequency based on the terminal type information, terminal measurement information, and overall cell traffic load information received in step S305, and if the terminal 100 supports the NR CA function, whether to stop the NR CA function can be determined (S30).

The operation of S30 according to whether the terminal 100 supports the NR CA function is described in detail as follows. At this time, the terminal 100 may be classified into the terminal types described in Table 1.

If the terminal 100 is UE _A and UE _B in Table 1, that is, if the terminal does not support the NR CA function, since the terminal 100 does not support NR CA, one 5G frequency, that is, NR frequency or LB frequency can only be connected to When the UE 100 is UE _C in Table 1, that is, when the UE 100 is a UE supporting NR CA, UE _C supports NR CA and thus can be connected to one or more frequency cells.

For all three terminal types, the NR base station 200 may determine a primary cell from f _N cells or f _L cells based on the radio channel quality measured by the terminal 100 . The radio channel quality may be measured by a reference signal received power (RSRP), a reference signal received quality (RSRQ), a signal to interference plus noise ratio (SINR) parameter, or a combination thereof.

At this time, the NR base station 200, when the channel quality of the NR frequency (f _N ) cell is less than the reference value (P(f _N )≤Th ₁ ) or the channel quality difference between the f _N cell and the f _L cell is greater than the reference value (Q (|f _L -f _n |)≥Th ₂ ), the f _L cell is determined as the primary cell.

In addition, the NR base station 200 determines that the channel quality of the NR frequency (f _N ) cell exceeds the reference value (P(f _N ) > Th ₁ ) or the channel quality difference between the f _N cell and the f _L cell is less than the reference value (Q If (| f _L - f _n |) < Th ₂ ) is satisfied, the f _N cell is determined as the primary cell.

Here, P and Q represent respective radio channel quality values, Th ₁ is a reference value to be compared with the P value, and Th ₂ is a reference value to be compared with the Q value.

In addition, if the terminal type is UE _C , During DSS operation, the bandwidth of the low-band frequency f _L is limited compared to f _N , so it is sensitive to the traffic load. Therefore, in order to prevent traffic overload, the NR CA function is not operated when the entire cell traffic load (μ) of f _L is greater than the reference value along with the primary cell change procedure.

That is, the NR base station 200 determines to turn off the NR CA function when μ > Th ₃ is satisfied. The NR base station 200 determines to turn on the NR CA function when μ < Th ₃ is satisfied. Here, Th ₃ is a reference value to be compared with the μ value.

On the other hand, if the GPS (Global Positioning System) sensor of the terminal 100 is used to supplement the primary cell change determination based on the radio channel quality, f _N (eg, 3.5 GHz) cells are relatively weak indoors and high-rise buildings Primary cell change determination can be more accurate in this dense outdoor weak electric field area. That is, the NR base station 200 determines whether the received signal strength (σ) or the number of available satellites (η) of positioning satellites (eg, GPS/GNSS (Global Navigation Satellite System)) measured by the terminal 100 is less than or equal to the reference value, The f _L cell may be determined as the NR primary cell.

The NR base station 200 may set the NR primary cell as f _L cell when σ < Th ₄ is satisfied, and set the NR primary cell as f _N cell when σ > Th ₄ is satisfied. Alternatively, the NR base station 200 may set the NR primary cell to the f _L cell when η < Th ₅ is satisfied, and set the NR primary cell to the f _N cell when η > Th ₅ is satisfied. Here, Th ₄ is a reference value to be compared with the σ value, and Th ₅ is a reference value to be compared with the η value.

At this time, although the primary cell is determined by AND condition of the received signal strength (σ) and the number of available satellites (η), only one of the received signal strength (σ) and the number of available satellites (η) can be obtained according to the embodiment. If possible, the primary cell may be determined using an OR condition.

As described above, the NR base station 200 may determine the primary cell based on the radio channel quality and the received signal strength (σ) or the number of available satellites (η). In this case, examples of combining the radio channel quality and the received signal strength (σ) or the number of available satellites (η) may vary.

Since the received signal strength (σ) or the number of available satellites (η) is a criterion for determining the f _N weak electric field area, according to one example, if f _N cell is determined as the primary cell based on the radio channel quality In addition, the condition of the received signal strength (σ) or the number of available satellites (η) is determined, and even in this case, if the _fN cell is determined as the primary cell, the _fN cell may be finally determined as the primary cell. On the other hand, _if the NR base station 200 does not satisfy the condition of the received signal strength (σ) or the number of available satellites (η), even if the f _N cell is determined as the primary cell based on the radio channel quality, the final As a result, the primary cell may be determined as the f _L cell.

In this way, when the primary cell is determined, the NR base station 200 may generate base station configuration update information including a primary cell indicator and an indicator indicating whether the NR CA function is stopped (S307). Here, the NR CA function stop indicator is provided to the terminal supporting the NR CA function in S306.

After S305, the NR base station 200 determines whether the terminal 100 is connected to the NR base station (S306), and transmits a terminal control request to the LB base station 300 for the terminal 100 that has not accessed the NR base station ( S307). Here, the UE control request may be a newly defined procedure or may use one of the procedures specified in the Xn interface standard. The UE control request may include the primary cell indicator determined in S305 and the NR CA on/off indicator.

The LB base station 300 may transmit an RRC message including a primary cell indicator and an NR CA on/off instruction to the corresponding terminal 100 according to the information received in step S307 (S308). Through this, the terminal 100 may access the primary cell determined in S305 and perform NR CA on/off.

S307 to S308 may be performed when the terminal 100 is located in the LB frequency coverage, eg, in the outskirts of a rural area in FIG. 2 .

In addition, an RRC message including a primary cell indicator and an NR CA on/off instruction may be transmitted to the corresponding terminal 100 for the terminal 100 connected to the NR base station 200 in S306 (S309). Through this, the terminal 100 may access the primary cell determined in S305 and perform NR CA on/off.

According to another embodiment, primary cell and NR CA on/off may be determined based on the network slicing ID.

In general, the 5G eMBB service can provide a wide bandwidth and fast transmission rate by utilizing NR CA between a 3.5GHz NR frequency (f _N ) and a low-band frequency LB frequency (f _L ).

It is advantageous for 5G URLLC service to utilize a single frequency such as an NR frequency (eg, 3.5 GHz) capable of ultra-low latency transmission due to its short Transmission Time Interval (TTI) characteristics.

5G mMTC service provides stable and wide coverage rather than fast transmission speed, and minimizes handover and multi-connection to reduce power consumption of the terminal as much as possible. Therefore, it is advantageous to use low-band frequencies such as LB frequency (f _L ) do.

In addition, since the 5G V2X service supports fast mobility of the terminal and requires wide coverage, it is advantageous to utilize a low-band frequency such as LB frequency (f _L ).

Based on these contents, the NR base station 200 may determine a primary cell based on the network slicing ID and determine on/off of the NR CA.

Network Slicing ID service type primary cell NR CA NS ₁ eMBB NR frequency on NS ₂ URLL NR frequency off NS ₃ mMTC LB frequency off NS ₄ V2X LB frequency off

Referring to Table 3, when the network slicing ID indicates eMBB or URLL, which is a speed-critical service, the primary cell is selected as the NR base station 200. In addition, when the network slicing ID indicates a coverage-important service, that is, mMTC and V2X, which are services in which a service provision range is important, the primary cell is selected as the LB base station 300. In addition, since the LB frequency (f _L ) has a large impact on the LTE service, the NR CA operation is turned off for all services except for eMBB where bandwidth is important.

In this way, the NR base station 200 may determine whether to use the primary cell and CA in units of service.

9 illustrates an NR primary cell selection procedure according to another embodiment.

Referring to FIG. 9, the NR base station 200 requests and receives network slice information of a terminal from the 5G core network 400 (S401). In this case, the network slice information may be slice identifier information (Slice Identifier, SID).

The NR base station 200 may change the NR primary cell and NR CA settings based on the slice identifier information (SID) (S402). Here, the SID may be mapped to Single Network Slice Selection Assistance Information (S-NSSAI) or Slice Service Type (SST).

In this case, the NR base station 200 may determine to change the NR primary cell to f _N cell and change the NR CA to on when the SID is NS ₁ of Table 1. When the SID is NS ₂ of Table 1, the NR base station 200 may determine to change the NR primary cell to f _N cell and change the NR CA to off. When the SID is NS ₃ of Table 1, the NR base station 200 may decide to change the NR primary cell to f _L cell and change the NR CA to off. When the SID is NS ₄ of Table 1, the NR base station 200 may decide to change the NR primary cell to f _L cell and change the NR CA to off.

Here, NS ₁ means a network slice corresponding to eMBB. NS ₂ means a network slice corresponding to URLLC. NS ₃ denotes a network slice corresponding to mMTC. NS ₄ means a network slice corresponding to V2X.

The NR base station 200 determines whether the terminal 100 is connected to the NR base station (S403) and transmits a terminal control request to the LB base station 300 for the terminal 100 that has not accessed the NR base station 200 ( S404). Here, the UE control request may be a newly defined procedure or may use one of the procedures specified in the Xn interface standard. The UE control request may include the primary cell indicator determined in S305 and the NR CA on/off indicator.

The LB base station 300 may transmit an RRC message including a primary cell indicator and an NR CA on/off indication to the corresponding terminal 100 according to the information received in step S404 (S405). Through this, the terminal 100 may access the primary cell determined in S305 and perform NR CA on/off.

S404 to S405 may be performed when the terminal 100 is located in the LB frequency coverage, eg, in the outskirts of a rural area in FIG. 2 .

In addition, an RRC message including a primary cell indicator and an NR CA on/off instruction may be transmitted to the corresponding terminal 100 for the terminal 100 connected to the NR base station 200 in S403 (S406). Through this, the terminal 100 may access the primary cell determined in S406 and perform NR CA on/off.

In addition, the network slice ID (SID) can be received by the NR base station 200 and the LB base station 300 from the core network 400 or the terminal 100 . In the case of the LB base station 300, the SID obtained from the terminal 100 or the core network 400 can be transmitted to the NR base station 200, and the transmission process is the inter-cell resource negotiation request / response (E-UTRA- NR Cell Resource Coordination Request/Response) procedure may be used.

The embodiments of the present invention described above are not implemented only through devices and methods, and may be implemented through programs that realize functions corresponding to the configuration of the embodiments of the present invention or a recording medium on which the programs are recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. that fall within the scope of the right.

Claims (20)

A method of operating a first base station using a first service frequency for 5G service in an environment in which a plurality of cells using different radio frequencies overlap,
Checking traffic load information from a second base station providing the 5G service and LTE service through a second service frequency different from the first service frequency;
Based on the 5G traffic information obtained by summing the 5G traffic information of the first base station and the 5G traffic information of the second base station, frequency sharing of the second base station is performed using a Dynamic Spectrum Sharing (DSS) method or a Static Spectrum Sharing (SSS) method. the step of deciding whether to, and
Transmitting the determined information to the second base station
Including, method. In paragraph 1,
The determining step is
Based on the traffic load information, if the load ratio of the 5G service subscribing terminal to the load of the LTE service subscribing terminal connected to the second base station is less than the reference ratio, frequency sharing is determined as DSS, and if it is greater than the reference ratio, the A method for determining frequency sharing with SSS. In paragraph 1,
The determining step is
Based on the traffic load information, if the ratio of the 5G traffic load to the LTE traffic load of the second base station is less than the reference ratio, select frequency sharing as DSS and if greater than the reference ratio, select the frequency sharing as SSS , method. In paragraph 1,
The sending step is
A method comprising a DSS operation indicator or an SSS operation indicator. In paragraph 1,
The sending step is
When SSS is determined, a method of transmitting information on the bandwidth allocated to the 5G service and the bandwidth allocated to the LTE service. A method of operating a first base station using a first sub-frequency in an environment in which a plurality of cells using different radio frequencies overlap, the method comprising:
Receiving radio channel quality information obtained from a second base station providing the 5G service and LTE service through a second service frequency different from the first service frequency;
Determining a primary cell of a terminal as the first service frequency or the second service frequency based on the radio channel quality information; and
instructing a terminal connected to the second base station or a terminal connected to the first base station to change a primary cell according to the determined information;
How to include. In paragraph 6,
The determining step is
If the radio channel quality of the second service frequency is less than or equal to the reference value or if the difference between the radio channel quality of the first service frequency and the radio channel quality of the second service frequency is greater than or equal to the reference value, the primary cell of the terminal is set to the first How to determine the service frequency. In paragraph 7,
The determining step is
If the terminal is a terminal that does not support carrier aggregation for the first service frequency, determining a primary cell of the terminal as the first service frequency. In paragraph 7,
The determining step is
If the radio channel quality of the first service frequency is less than or equal to the reference value or the difference between the radio channel quality of the second service frequency and the radio channel quality of the first service frequency is greater than or equal to the reference value, the primary cell of the terminal is selected as the second service frequency. How to determine the service frequency. In paragraph 6,
The determining step is
If the total traffic load of the second service frequency is equal to or greater than a reference value, determining to stop carrier aggregation for the first service frequency for the terminal. In paragraph 6,
The determining step is
determining a primary cell of the terminal as the second service frequency when the received signal strength of positioning satellites or the number of available satellites measured by the terminal is equal to or less than a reference value. A method of operating a first base station using a first sub-frequency in an environment in which a plurality of cells using different radio frequencies overlap, the method comprising:
Checking network slice information of the terminal;
Selecting a primary cell of the terminal from among the first service frequency or a second service frequency different from the first service frequency, based on network slice information of the terminal; and
Transmitting the selected primary cell indicator to the terminal
How to include. In paragraph 12,
The selection step is
When the network slice information indicates a service for which coverage is important, determining the second service frequency having a relatively wide coverage as a primary cell. In paragraph 12,
The determining step is
When the network slice information indicates a service for which speed is important or a service requiring minimized delay, determining the first service frequency having a wide bandwidth as a primary cell. In paragraph 12,
The determining step is
A method of turning off frequency carrier aggregation when the network slice information indicates services other than a bandwidth-important service. a first base station using a first service frequency; and
A second base station using a second service frequency different from the first service frequency;
The first base station,
Based on the information received from the second base station through inter-base station communication, at least one of a frequency sharing method, a primary cell, and a carrier aggregation of a terminal is determined, and the second base station is configured to operate according to the determined method. Requesting heterogeneous wireless network interworking system. In clause 16,
The first base station,
A system for interworking with heterogeneous wireless networks for selectively determining a frequency sharing method of the second base station as DSS or SSS based on real-time traffic load information obtained from the second base station. In clause 16,
The first base station,
A system for interworking with heterogeneous wireless networks for determining a primary cell based on radio channel quality or traffic load according to whether a terminal connected to the second base station supports carrier aggregation. In clause 16,
The first base station,
The heterogeneous wireless network interworking system for determining at least one of a primary cell or carrier aggregation on/off based on a network slicing ID being used by the terminal. In clause 16,
The first base station,
A heterogeneous wireless network interworking system that requests the second base station through a cell resource coordination procedure between base stations and a base station configuration update procedure.

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