Method and apparatus for requesting system information using a preamble in a next generation mobile communication system

Abstract

The present disclosure relates to a communication scheme and system thereof that integrates a 5G communication system and Internet of Things technology that supports a higher data transmission rate than a 4G system. The present disclosure can be applied to smart services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail business, security and safety-related services, etc.) based on 5G communication technology and Internet of Things-related technologies. The present invention provides a method and apparatus for effectively sending or receiving system information by using a preamble in a next-generation mobile communication system.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for operating a UE and an eNB to request system information in a next generation mobile communication system. Background Art

[0002] In order to meet the increased demand for wireless data services since the commercialization of 4G communication systems, efforts have been made to develop improved 5G communication systems or pre-5G communication systems. For this reason, 5G communication systems or pre-5G communication systems are referred to as super 4G network communication systems or post-LTE systems. In order to achieve high data transmission rates, 5G communication systems are being considered for implementation in millimeter wave bands (e.g., 60 GHz bands).

[0003] In 5G communication systems, technologies such as beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas are being discussed to mitigate propagation path loss in the millimeter wave band and increase propagation transmission distance. In addition, 5G communication systems have developed technologies such as evolved small cells, advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communications, coordinated multipoint (CoMP), and reception interference cancellation to improve system networks.

[0004] In addition, 5G systems have developed advanced coding modulation (ACM) schemes (such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC)) and advanced access technologies (such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA)).

[0005] The Internet has evolved from a human-centric connection network where humans generate and consume information to an Internet of Things (IoT) network where information is exchanged between distributed components such as objects. Internet of Everything (IoE) technology has emerged, in which big data processing technology is combined with IoT technology through connection with cloud servers, etc. In order to realize the IoT, technical factors such as sensing technology, wired / wireless communication, network infrastructure, service interface technology, and security technology are required, and research on technologies for connection between objects, such as sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc., has recently been conducted.

[0006] In the IoT environment, by collecting and analyzing data generated in connected objects, intelligent Internet technology (IT) services that create new value in people's lives can be provided. IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars, connected cars, smart grids, healthcare, smart home devices or high-tech medical services by integrating traditional information technology (IT) and various industries.

[0007] Therefore, various attempts are being made to apply 5G communications to IoT networks. For example, beamforming, MIMO, and array antenna schemes are used to implement technologies such as sensor networks, machine-to-machine (M2M), and machine-type communications (MTC). The application of cloud RAN as a big data processing technology can be an example of the fusion of 5G technology and IoT technology.

[0008] With the development of next generation mobile communication systems, new methods and research on preamble transmission have attracted attention. Specifically, new communication systems need to improve methods and devices for smoothly performing the process of sending a preamble to issue a request for system information. Summary of the invention

[0009] Technical issues

[0010] Aspects of the present disclosure propose a preamble for requesting system information in a wireless communication system, and propose a series of processes for transmitting and receiving the system information through the proposed preamble.

[0011] Another aspect of the present disclosure proposes a message for requesting system information in a wireless communication system, and proposes a series of processes for transmitting and receiving the system information through the proposed message.

[0012] Yet another aspect of the present disclosure proposes a method by which, when measuring cells and reporting results thereof, a UE that simultaneously transmits and receives data using multiple Radio Access Technologies (RATs) in a wireless communication system enables an eNB to accurately add / release cells and accurately determine handover.

[0013] Workaround

[0014] According to an aspect of the present disclosure, a method of an eNB in ​​a wireless communication system is provided. The method includes: sending a configuration message to a UE, the configuration message including information about a plurality of frequencies as measurement objects and threshold information of signal strength (reference signal received power (RSRP)) related to the measurement of the plurality of frequencies; and receiving a measurement report message based on the configuration message from the UE, wherein the configuration message also includes indication information, and the indication information indicates measurement of at least one of the plurality of frequencies regardless of the threshold information.

[0015] According to another aspect of the present disclosure, a method of a UE in a wireless communication system is provided. The method includes: receiving a configuration message from an eNB, the configuration message including information about a plurality of frequencies as measurement objects and threshold information of reference signal received power (RSRP) related to the measurement of the plurality of frequencies; performing measurement based on the configuration message; and sending a measurement report message including a result of the measurement performed based on the configuration message to the eNB, wherein the configuration message also includes indication information, and the indication information indicates measurement of at least one of the plurality of frequencies regardless of the threshold information.

[0016] According to another aspect of the present disclosure, an eNB in ​​a wireless communication system is provided. The eNB includes: a transceiver; and a controller configured to send a configuration message to a UE, the configuration message including information about a plurality of frequencies as measurement objects and threshold information of signal strength (reference signal received power (RSRP)) related to the measurement of the plurality of frequencies; and control the transceiver to receive a measurement report message based on the configuration message from the UE, wherein the configuration message also includes indication information, and the indication information indicates measurement of at least one of the plurality of frequencies regardless of the threshold information.

[0017] According to another aspect of the present disclosure, a UE in a wireless communication system is provided. The UE includes: a transceiver; and a controller configured to control the transceiver to receive a configuration message from an eNB, the configuration message including information about multiple frequencies as measurement objects and threshold information of reference signal transmission power (RSRP) related to the measurement of the multiple frequencies; perform measurement based on the configuration message, and control the transceiver to send a measurement report message including a result of the measurement performed based on the configuration message to the eNB, wherein the configuration message also includes indication information, regardless of the threshold information, the indication information indicates measurement of at least one of the multiple frequencies.

[0018] According to another aspect of the present disclosure, a method of a UE in a wireless communication system is provided. The method includes: receiving first system information from an eNB; requesting second system information other than the first system information through a selected message based on the first system information; and when the second system information is not received in response to the request, requesting the second system information again after a backoff time determined by a preset backoff indicator, wherein the backoff indicator is applied in different ways according to the selected message.

[0019] According to another aspect of the present disclosure, a method of an eNB in ​​a wireless communication system is provided. The method includes: sending first system information to a UE; receiving a request for second system information other than the first system information from the UE through a selected message based on the first system information; and receiving a request for the second system information from the UE again after a backoff time determined by a preset backoff indicator, wherein the backoff indicator is applied in different ways according to the selected message.

[0020] According to another aspect of the present disclosure, a UE in a wireless communication system is provided. The UE includes: a transceiver; and a controller configured to receive first system information from an eNB, request second system information other than the first system information through a selected message based on the first system information, and when the second system information is not received in response to the request, request the second system information again after a backoff time determined by a preset backoff indicator, wherein the backoff indicator is applied in different ways according to the selected message.

[0021] According to another aspect of the present disclosure, an eNB in ​​a wireless communication system is provided. The eNB includes: a transceiver; and a controller, the controller being configured to send first system information to a UE, receive a request for second system information other than the first system information from the UE through a selected message based on the first system information, and receive a request for the second system information again from the UE after a backoff time determined by a preset backoff indicator, wherein the backoff indicator is applied in different ways according to the selected message.

[0022] Beneficial Effects

[0023] According to the embodiments of the present disclosure, the message transmission / reception process between the UE and the eNB can be improved, and thus the system information transmission / reception process can be performed smoothly and efficiently.

[0024] According to another embodiment of the present disclosure, the UE reduces the power consumption required to measure neighboring eNBs, and measures and reports different types of eNBs in a timely manner, and thus the eNB can add the corresponding measured eNB to the UE or move the UE to the corresponding measured eNB, so that the UE can use the corresponding eNB in ​​a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1a shows the architecture of the next generation mobile communication system;

[0026] Figure 1b A method for providing system information in a next generation mobile communication system is shown;

[0027] Figure 1c shows the random access process in a conventional LTE system;

[0028] Figure 1d The process of selecting the SI request method based on msg-1 or the SI request method based on msg-3 according to the present disclosure is shown;

[0029] Figure 1e shows the SI request process based on msg-1 according to the present disclosure;

[0030] Figure 1f A method of indicating an SI request for a dedicated preamble according to the present disclosure is shown;

[0031] Figure 1g The format of a random access response message according to the present disclosure is shown;

[0032] Figure 1h A method of configuring a sub-header including a backoff indicator according to the present disclosure is shown;

[0033] Figure 1i is a flow chart illustrating the operation of a UE according to the present disclosure;

[0034] Figure 1j A method of indicating system information of a target cell during a handover procedure according to the present disclosure is shown;

[0035] Figure 1k is a flow chart illustrating an operation of a UE indicating system information of a target cell during a handover procedure according to the present disclosure;

[0036] Figure 1l is a block diagram showing the internal structure of a UE to which the present disclosure is applied;

[0037] Figure 1m is a block diagram showing the configuration of an eNB according to the present disclosure;

[0038] Figure 2a shows the architecture of the next generation mobile communication system;

[0039] Figure 2b A method for providing system information in a next generation mobile communication system is shown;

[0040] Figure 2c shows the random access process in a conventional LTE system;

[0041] Figure 2d The process of selecting the SI request method based on msg-1 or the SI request method based on msg-3 according to the present disclosure is shown;

[0042] Figure 2e The SI request process based on msg-3 according to the present disclosure is shown;

[0043] Figure 2f A method for configuring an SI request MAC CE according to the present disclosure is shown;

[0044] Figure 2g A method for configuring UE ID MAC CE according to the present disclosure is shown;

[0045] Figure 2h A method for configuring a UE contention resolution identifier included in msg4 according to the present disclosure is shown.

[0046] Figure 2i is a flow chart illustrating the operation of a UE according to the present disclosure;

[0047] Figure 2j The process of handling the case where general random access and SI request random access overlap with each other in the present disclosure is shown;

[0048] Figure 2k is a flowchart illustrating an operation of a UE when a general random access and an SI request random access overlap with each other in the present disclosure;

[0049] Figure 2l is a block diagram showing the internal structure of a UE to which the present disclosure is applied;

[0050] Figure 2m is a block diagram showing the configuration of an eNB according to the present disclosure;

[0051] Figure 3a The structure of the LTE system referred to for the description of the present disclosure is shown;

[0052] Figure 3b The wireless protocol structure of the LTE system referred to for the description of the present disclosure is shown;

[0053] Figure 3c The concept of multiple connections in LTE and NR is shown.

[0054] Figure 3d An example of a message flow between a UE and an eNB when the present disclosure is applied is shown;

[0055] Figure 3e is a flowchart showing the operation of a UE when the present disclosure is applied; and

[0056] Figure 3f is a block diagram illustrating a UE according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0057] Hereinafter, embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings. In the following description of the present disclosure, detailed descriptions of known functions and configurations included herein will be omitted when it may cause the subject matter of the present disclosure to be unclear. The terms to be described below are defined in consideration of the functions in the present disclosure and may vary depending on the user, the user's intention, or convention. Therefore, the definition of the term should be formulated based on the content of the entire specification.

[0058] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the methods for achieving the same will become apparent. However, the present disclosure is not limited to the embodiments described below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and convey the scope of the present disclosure to those skilled in the art, and the present disclosure is limited only by the scope of the attached claims. Throughout the specification, the same or similar reference numerals refer to the same or similar elements.

[0059] <First Embodiment>

[0060] Figure 1a The structure of the next generation mobile communication system is shown.

[0061] refer to Figure 1a ,like Figure 1a As shown in , the radio access network of the next generation mobile communication system includes a next generation base station (hereinafter referred to as NR NB (New Radio Node B)) 1a-10 and a new radio core network (NR CN) 1a-05. The user terminal (hereinafter referred to as NR UE (New Radio User Equipment) or UE) 1a-15 accesses the external network through the NR NB 1a-10 and the NRCN 1a-05.

[0062] exist Figure 1a In the NR NB 1a-10, the NR NB 1a-10 corresponds to the evolved Node B (eNB) in the conventional LTE system. The NR NB 1a-10 can be connected to the NR UE 1a-15 through a radio channel and can provide better services than the conventional Node B. Since all user services are provided through a shared channel in the next generation mobile communication system, a device for collecting and scheduling status information of a buffer status, an available transmission power status, and a channel status of the UE is required, and it corresponds to the NR NB 1a-10.

[0063] One NR NB usually controls multiple cells. Compared with conventional LTE, NR NB can have a wider bandwidth than the conventional maximum bandwidth to achieve ultra-high-speed data transmission, and can also apply beamforming technology by using orthogonal frequency division multiplexing (OFDM) as a radio access technology. In addition, an adaptive modulation and coding (hereinafter, referred to as AMC) scheme that determines a channel coding rate and a modulation scheme corresponding to a channel state of a UE is applied to the LTE system.

[0064] NR CN 1a-05 performs functions of supporting mobility, configuring bearers, and configuring quality of service (QoS). NR CN 1a-05 is a device for performing management of UE mobility and various control functions, and is connected to multiple eNBs. In addition, the next generation mobile communication system can be linked with the legacy LTE system, and NR CN 1a-05 is connected to MME 1a-25 through a network interface. MME1a-25 is connected to eNB 1a-30 which is a legacy eNB.

[0065] Figure 1b A method for providing system information in a next generation mobile communication system is shown.

[0066] In the next generation mobile communication system, the system information broadcast by gNB 1b-10 is mainly divided into minimum system information (SI) and other system information.

[0067] As shown in reference numeral 1b-15, the minimum SI is broadcast periodically and includes configuration information required for initial access and SI scheduling information required to receive other SI broadcast periodically or in response to a request. Basically, other SI includes all configuration information not included in the minimum SI.

[0068] Other SI is periodically broadcast as shown in reference numeral 1b-20 or periodically broadcast in response to a request from the UE, or is provided to the UE through dedicated signaling as shown in reference numeral 1b-25. When other SI is received by UE request, the UE is required to identify whether other SI in the cell is valid or whether other SI is currently being broadcast (through a request from another UE) before the request. The identification can be performed through specific information provided by the minimum SI.

[0069] Idle mode (RRC_IDLE) UE or inactive mode (RRC_INACTIVE) UE can request other SI without changing the current RRC state. Connected mode (RRC_CONNECTED) UE can request and receive other SI through dedicated RRC signaling. Other SI is broadcast at a predetermined period for a predetermined time period. Public Warning System (PWS) information is classified as other SI and provided. Whether to broadcast other SI or provide the SI to the UE through dedicated RRC signaling is implemented by the network.

[0070] Figure 1c The random access process in the conventional LTE system is shown.

[0071] Random access is performed when uplink synchronization is performed or data is sent to the network. More specifically, random access can be performed when switching from idle mode to connected mode, when RRC reconstruction is performed, when handover is performed, and when uplink / downlink data transmission starts. Upon receiving a dedicated preamble from gNB 1c-10, UE 1c-05 applies and sends the preamble. Otherwise, the UE selects one of the two preamble groups and selects the preamble belonging to the selected group. The groups are referred to as group A and group B. If the channel quality state is higher than a specific threshold and the size of msg 3 is greater than a specific threshold, the UE selects the preamble belonging to group B, otherwise, the UE selects the preamble belonging to group A.

[0072] As indicated by reference numeral 1c-15, the preamble is transmitted in the nth subframe. When the preamble is transmitted in the nth subframe, the random access response (RAR) window starts from the n+3th subframe, and monitors whether the RAR is transmitted within the window time interval as indicated by reference numeral 1c-20. The scheduling information of the RAR is represented by the RA-RATI of the PDCCH. The RA-RNTI is triggered using the position of the radio resource on the time and frequency axis for transmitting the preamble.

[0073] RAR includes a timing advance command, UL grant, and temporary C-RNTI. As shown in the figure 1c-25, if RAR is successfully received in the RAR window, msg 3 is sent using the information of the UL grant included in the RAR. Depending on the purpose of random access, msg 3 includes different information. The following [Table 1] is an example of the information carried on msg 3.

[0074] [Table 1]

[0075]

[0076] If RAR is received in the nth subframe, msg3 is transmitted in the n+6th subframe. Hybrid automatic repeat request (HARQ) is applied to msg 3 and thereafter. As shown in the figure 1c-30, after transmitting msg 3, the UE drives a specific timer and monitors a contention resolution (CR) message before the timer expires. The CR message includes an RRC connection establishment message or an RRC connection reestablishment message depending on the purpose of random access, and a CR medium access control (MAC) control element (CE).

[0077] Figure 1d The process of selecting the msg 1-based or msg 3-based SI request method according to the present disclosure is shown.

[0078] To request system information other than the minimum SI, the UE uses random access.

[0079] The UE requests the network for the system information that the UE wishes to receive through msg 1 (preamble) or msg 3. In step 1d-05, the UE determines whether the PRACH resource information that can be used for SI request is included in the periodically broadcast minimum SI. The PRACH resource information may include preamble ID (or index) information (prach-ConfigIndex) for SI request and radio resource information for sending preamble.

[0080] When this information is included, in step 1d-10, the UE may request system information other than the minimum SI through msg 1 dedicated to SI request. Otherwise, in step 1d-15, the UE requests system information other than the minimum SI through msg 3. At this time, the UE transmits a preamble for general random access.

[0081] Figure 1e The msg-1 based SI request process according to the present disclosure is shown.

[0082] In step 1e-15, UE 1e-05 receives minimum SI from network 1e-10. Minimum SI may include an ID (index) of a dedicated preamble for SI request and radio resource information for transmitting the preamble.

[0083] In step 1e-20, the UE triggers a request for system information other than the minimum SI. In step 1e-25, the UE determines whether dedicated preamble information for SI request is included in the minimum SI.

[0084] If a dedicated preamble can be sent, the UE selects a preamble corresponding to the requested system information in step 1e-30 and sends the preamble to the network in step 1e-35. In step 1e-40, the network sends a RAR to the UE for the purpose of acknowledgment (ACK). The RAR may include one or more subheaders with a backoff indicator (BI).

[0085] The backoff indicator is used to derive a backoff time during which the UE should wait to perform a retry when the UE fails random access. For example, a value may be selected from a value between 0 and the backoff indicator by uniform distribution, and the selected value may be configured as the backoff time. The subheader including the BI may be defined separately according to general random access, msg-1-based SI request, or msg-3-based SI request.

[0086] A subheader with an ID of the transmitted preamble may be included, and the MAC RAR corresponding to the subheader may include radio resource information through which the requested system information is broadcast. The radio resource information may be included in the minimum SI. The radio resources may be generally used for unicast transmission, and if the UE requests specific system information, the radio resources may be used to broadcast the system information.

[0087] If the RAR is not received within the SI window, or if the received RAR does not include a subheader with the ID of the transmitted preamble, the preamble transmission is considered to have failed. Then, after waiting for the backoff time derived from the corresponding BI, the UE may send the preamble for SI request again. In step 1e-60, the UE successfully receives the relevant RAR, and then in step 1e-65, the UE receives the requested system information in the configured radio resources.

[0088] Figure 1f A method of indicating an SI request for a dedicated preamble according to the present disclosure is shown.

[0089] If the 0th to xth preamble codes can be used in the next generation mobile communication system, the 0th to xth preamble codes can be classified as preamble codes 1f-05 or general random access, the k+1th to x-n+1th preamble codes can be classified as dedicated preamble codes 1f-10, and the x-n+2th to xth preamble codes can be classified as preamble codes 1f-15 for SI requests.

[0090] Each preamble used for SI request may be designated to request specific system information. For example, among the preambles used for SI request, the preamble corresponding to the lowest index value may be used to request all system information except the minimum SI. The preamble corresponding to the next index value may be used to request the system information included in the first SI message. The preamble corresponding to the next next index value may be used to request the system information included in the second SI message. Alternatively, the SI message may be replaced by a system information block (SIB).

[0091] Figure 1g The format of a random access response message according to the present disclosure is shown.

[0092] In a mobile communication system, a RAR includes one or more subheaders and one or more MAC RARs. Figure 1g In the MAC header 1g-15 including one or more subheaders, the MAC header 1g-15 is located at the front of the RAR, but the subheader may be located at another part of the RAR. As indicated by the reference numeral 1g-05, some of the subheaders may include a BI, and there may be no MAC RAR corresponding to the subheader. In addition, in the subheader 1g-10 including the preamble ID, there is one MAC RAR 1g-20 corresponding thereto.

[0093] Figure 1h A method of configuring a sub-header including a backoff indicator according to the present disclosure is shown.

[0094] Figure 1h (a) shows the E / T / R / R / BI MAC subheader in the conventional LTE technology. Field E1h-05 indicates whether there is another MAC subheader. Field T1h-10 is used to indicate whether the corresponding subheader is a subheader including BI 1h-15 or a subheader including a random access preamble ID (RAPID). Field R is a reserved bit. Field BI is used to derive the backoff time and has a total size of 4 bits.

[0095] The present disclosure provides BIs for general random access, random access for SI request based on msg-1, and random access for SI request based on msg-3, respectively. To this end, a field T11h-20 indicating which type of random access the BI corresponds to is added to the MAC subheader.

[0096] Figure 1h (b) is an example of a MAC subheader proposed by the present disclosure. In this embodiment, a conventional 2-bit field R is used as a field indicating which type of random access corresponds to the BI.

[0097] Figure 1h(c) shows some MAC headers in which MAC subheaders including 3 types of BI are arranged in a row. For example, if the field T1 is configured as 00 1h-25, BI 1h-30 included in the corresponding MAC subheader is applied to general random access, if the field T1 is configured as 01 1h-35, BI 1h-40 included in the corresponding MAC subheader is applied to random access based on SI request of msg-1, and if the field T1 is configured as 10 1h-45, BI 1h-50 included in the corresponding MAC subheader is applied to random access based on SI request of msg-3. If the field is 11, the BI included in the corresponding MAC subheader is applied to all types of random access.

[0098] In another embodiment, BI may be applied only to random access requested based on SI of msg-3, but not to random access requested based on SI of msg-1.

[0099] Figure 1i is a flow chart illustrating the operation of a UE according to the present disclosure.

[0100] In step li-05, the UE receives the minimum SI including the PRACH radio resources allocated for the SI request from the network. In step 1i-10, the UE triggers the SI request procedure. In step 1i-15, the UE selects the preamble for the SI request according to the SI message or SIB that the UE itself should request. In step 1i-20, the UE sends the preamble selected for the SI request.

[0101] In step 1i-25, the UE successfully receives the RAR. The RAR may include one or more MAC subheaders with BI. However, if a MAC subheader including a BI applied to the random access requested based on the SI of msg-1 is not received, the backoff time is considered to be 0. In step 1i-30, if the random access is considered to have failed, the UE drives the derived backoff timer according to the BI corresponding to the type of random access. If there is no corresponding BI, the backoff time is considered to be 0.

[0102] In step 1i-35, if the timer expires, the UE may resend the preamble of the SI request. In step 1i-40, the UE receives the requested SI from the network.

[0103] Figure 1j A method of indicating system information of a target cell during handover according to the present disclosure is shown.

[0104] In step 1j-20, UE 1j-05 receives the minimum SI from source gNB 1j-10. In step 1j-25, the UE may request the required SI from the source gNB through the configuration information required for the SI request included in the minimum SI. In step 1j-30, the source gNB sends the requested SI to the UE.

[0105] In step 1j-35, the source gNB determines to perform handover based on the measurement information received from the UE and sends a HO request message to the target gNB 1j-15. The HO request message includes the SI owned by the UE. In step 1j-40, the target gNB sends the SI information required when the UE stays in the target gNB to the source gNB based on the SI.

[0106] In step 1j-45, the source gNB sends a HO command message indicating handover to the UE, and the message includes SI information required when the UE stays in the target gNB, SI information that the target gNB can reuse in the SI of the currently applied source gNB, and an indicator indicating whether an SI request to the target gNB is required.

[0107] In step 1j-50, the UE successfully performs handover to the target gNB and sends a HO complete message. In step 1j-55, the UE determines whether to perform random access of SI request to the target gNB based on the SI-related information included in the HO command. Specifically, if the indicator indicates that SI request to the target gNB is not required, SI request is not made. In step 1j-60, when SI request to the target gNB is required, the UE performs random access of SI request to the target gNB.

[0108] Figure 1k is a flow chart illustrating an operation of a UE indicating system information of a target cell during a handover procedure according to the present disclosure.

[0109] In step 1k-05, the UE receives a HO command message indicating a handover from the network, and the message includes SI information required when the UE stays in the target gNB, SI information that the target gNB can reuse among the currently applied SI of the source gNB, and an indicator indicating whether an SI request to the target gNB is required.

[0110] In step 1k-10, the UE completes the operation of switching to the target cell. In step 1k-15, the UE determines whether an SI request to the target cell is required based on the SI related information. In step 1k-20, if the indicator indicates that an SI request is not required, the UE reuses the current SI information and does not make an SI request.

[0111] Figure 1l The structure of the UE is shown.

[0112] refer to Figure 1l , the UE includes a radio frequency (RF) processing unit 1l-10, a baseband processing unit 1l-20, a storage unit 1l-30 and a controller 1l-40.

[0113] The RF processing unit 11-10 performs functions of sending and receiving signals through a radio channel, such as frequency band conversion and amplification of signals. That is, the RF processing unit 11-10 up-converts the baseband signal provided by the baseband processing unit 11-20 into an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 11-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Although Figure 1l Only one antenna is shown, but a UE may include multiple antennas.

[0114] In addition, the RF processing unit 11-10 may include multiple RF chains. In addition, the RF processing unit 11-10 may perform beamforming. For beamforming, the RF processing unit 11-10 may control the phase and size of each signal sent / received through multiple antennas or antenna elements. In addition, the RF processing unit 11-10 may perform multiple-input multiple-output (MIMO) operations and receive multiple layers during MIMO operations.

[0115] The baseband processing unit 11-20 performs the function of converting between the baseband signal and the bit stream according to the physical layer standard of the system. For example, in data transmission, the baseband processing unit 11-20 generates complex symbols by encoding and modulating the transmission bit stream.

[0116] In addition, when receiving data, the baseband processing unit 11-20 reconstructs a received bit stream by demodulating and decoding a baseband signal provided from the RF processing unit 11-10. For example, in an orthogonal frequency division multiplexing (OFDM) scheme, when transmitting data, the baseband processing unit 11-20 generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion.

[0117] In addition, in data reception, the baseband processing unit 1l-20 divides the baseband signal provided by the RF processing unit 1l-10 in units of OFDM symbols, reconstructs the signal mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then reconstructs the received bit stream through demodulation and decoding.

[0118] The baseband processing unit 11-20 and the RF processing unit 11-10 transmit and receive signals as described above. Therefore, the baseband processing unit 11-20 and the RF processing unit 11-10 can be referred to as a transmitter, a receiver, a transceiver or a communication unit.

[0119] In addition, at least one of the baseband processing unit 11-20 and the RF processing unit 11-10 may include multiple communication modules to support multiple different radio access technologies. In addition, at least one of the baseband processing unit 11-20 and the RF processing unit 11-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., IEEE802.11) and cellular networks (e.g., LTE). In addition, different frequency bands may include super high frequency (SHF) (e.g., 2.5 GHz and 2 GHz) bands and millimeter (mm) wave (e.g., 60 GHz) bands.

[0120] The storage unit 11-30 stores data such as basic programs, applications, and setting information for UE operation. Specifically, the storage unit 11-30 can store information related to a second access node that performs wireless communication through a second radio access technology. The storage unit 11-30 provides the stored data according to a request from the controller 11-40.

[0121] The controller 11-40 controls the overall operation of the UE. For example, the controller 11-40 sends and receives signals through the baseband processing unit 11-20 and the RF processing unit 11-10. In addition, the controller 11-40 records data in the storage unit 11-30 and reads the data. To this end, the controller 11-40 may include at least one processor. For example, the controller 11-40 may include a communication processor (CP) that performs communication control and an application processor (AP) that controls a higher layer such as an application.

[0122] Figure 1m is a block diagram of a MeNB in ​​a wireless communication system according to an embodiment of the present disclosure.

[0123] like Figure 1m As shown in , the eNB includes an RF processing unit 1m-10, a baseband processing unit 1m-20, a backhaul communication unit 1m-30, a storage unit 1m-40 and a controller 1m-50.

[0124] The RF processing unit 1m-10 performs functions of sending and receiving signals through a wireless channel, such as frequency band conversion and amplification of the signal. That is, the RF processing unit 1m-10 up-converts the baseband signal provided from the baseband processing unit 1m-20 into an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 1m-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although Figure 1m Only one antenna is shown, but the first access node may include multiple antennas.

[0125] In addition, the RF processing unit 1m-10 may include multiple RF chains. In addition, the RF processing unit 1m-10 may perform beamforming. For beamforming, the RF processing unit 1m-10 may control the phase and size of each of the signals sent and received through multiple antennas or antenna elements. The RF processing unit 1m-10 may perform downlink MIMO operations by sending one or more layers.

[0126] The baseband processing unit 1m-20 performs a function of performing conversion between a baseband signal and a bit stream according to the physical layer standard of the first radio access technology. For example, in data transmission, the baseband processing unit 1m-20 generates complex symbols by encoding and modulating the transmission bit stream. In addition, in data reception, the baseband processing unit 1m-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processing unit 1m-10. For example, in the OFDM scheme, when sending data, the baseband processing unit 1m-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion.

[0127] In addition, in data reception, the baseband processing unit 1m-20 divides the baseband signal provided from the RF processing unit 1m-10 in units of OFDM symbols, reconstructs the signal mapped to the subcarriers through FFT operation, and then reconstructs the received bit stream through demodulation and decoding. The baseband processing unit 1m-20 and the RF processing unit 1m-10 transmit and receive signals as described above. Therefore, the baseband processing unit 1m-20 and the RF processing unit 1m-10 can be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0128] The backhaul communication unit 1m-30 provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit 1m-30 converts a bit stream sent from the BS to another node (e.g., another BS or a core network) into a physical signal, and converts a physical signal received from other nodes into a bit stream.

[0129] The storage unit 1m-40 stores basic programs, application programs, and data such as configuration information for the operation of the MeNB. Specifically, the storage unit 1m-40 may store information related to the bearer allocated to the accessed UE and the measurement results reported from the accessed UE. In addition, the storage unit 1m-40 may store information that is a reference for determining whether to allow or interrupt multiple accesses to the UE. The storage unit 1m-40 provides the stored data according to a request from the controller 1m-50.

[0130] The controller 1m-50 controls the overall operation of the MeNB. For example, the controller 1m-50 sends and receives signals through the baseband processing unit 1m-20 and the RF processing unit 1m-10 or the backhaul communication unit 1m-30. In addition, the controller 1m-50 records data in the storage unit 1m-40 and reads data. To this end, the controller 1m-50 may include at least one processor.

[0131] <Second Embodiment>

[0132] Figure 2a The structure of the next generation mobile communication system is shown.

[0133] refer to Figure 2a ,like Figure 2a As shown in the figure, the radio access network of the next generation mobile communication system includes a next generation base station (hereinafter referred to as a new radio node B (NR NB) 2a-10 and a new radio core network (NR CN) 2a-05. The user terminal (hereinafter referred to as a new radio user equipment (NR UE) or UE) 2a-15 accesses the external network through the NR NB 2a-10 and the NRCN 2a-05.

[0134] exist Figure 2a In the present invention, NR NB 2a-10 corresponds to an evolved Node B (eNB) in a conventional LTE system. NR NB 2a-10 can be connected to NR UE 2a-15 through a radio channel and can provide better services than a conventional Node B. Since all user services are provided through a shared channel in the next generation mobile communication system, a device for collecting and scheduling status information of a buffer status of a UE, an available transmission power status, and a channel status is required, and the device corresponds to NR NB 2a-10.

[0135] One NR NB usually controls multiple cells. Compared with conventional LTE, NR NB can have a wider bandwidth than the conventional maximum bandwidth to achieve ultra-high-speed data transmission, and can apply orthogonal frequency division multiplexing (OFDM) through radio access technology, and can also apply beamforming technology. In addition, according to the channel state of the UE, a modulation scheme that determines the channel coding rate and an adaptive modulation and coding (hereinafter, referred to as AMC) scheme are applied to the LTE system.

[0136] NR CN 2a-05 performs functions of supporting mobility, configuring bearers, and configuring QoS. NR CN is a device for performing management of UE mobility and various control functions, and is connected to multiple eNBs. In addition, the next generation mobile communication system can be linked with the conventional LTE system, and NR CN is connected to MME 2a-25 through a network interface. MME is connected to eNB2a-30 which is a conventional eNB.

[0137] Figure 2b A method for providing system information in a next generation mobile communication system is shown.

[0138] In the next generation mobile communication system, the system information broadcast by gNB 2b-10 is mainly divided into minimum system information (SI) and other system information.

[0139] As indicated by reference numeral 2b-15, the minimum SI is broadcast periodically and includes configuration information required for initial access and SI scheduling information required for receiving other SI, which is broadcast periodically or in response to a request.

[0140] Basically, other SI includes all configuration information not included in the minimum SI. Other SI is periodically broadcast as shown in reference numeral 2b-20 or periodically broadcast in response to a request from the UE, or is provided to the UE through dedicated signaling as shown in reference numeral 2b-25. When other SI is received by UE request, the UE is required to identify whether other SI in the cell is valid or whether other SI is currently being broadcast (through a request from another UE) before the request. The identification can be performed through specific information provided by the minimum SI.

[0141] Idle mode (RRC_IDLE) UE or inactive mode (RRC_INACTIVE) UE can request other SI without changing the current RRC state. Connected mode (RRC_CONNECTED) UE can request and receive other SI through dedicated RRC signaling. Other SI is broadcast for a predetermined period of time. Public Warning System (PWS) information is classified and provided as other SI. It is up to the network to broadcast other SI or provide the SI to the UE through dedicated RRC signaling.

[0142] Figure 2c The random access process in the conventional LTE system is shown.

[0143] Random access is performed when uplink synchronization is performed or when data is sent to the network. More specifically, random access may be performed when switching from idle mode to connected mode, when performing RRC reestablishment, when performing handover, and when uplink / downlink data transmission starts.

[0144] Upon receiving a dedicated preamble from gNB 2c-10, UE 2c-05 applies and transmits the preamble. Otherwise, the UE selects one of the two preamble groups and selects a preamble belonging to the selected group. The groups are called group A and group B. If the channel quality status is above a certain threshold and the size of msg 3 is greater than a certain threshold, the UE selects a preamble belonging to group B, otherwise, the UE selects a preamble belonging to group A.

[0145] As indicated by reference numeral 2c-15, the preamble is transmitted in the nth subframe. When the preamble is transmitted in the nth subframe, the RAR window starts from the n+3th subframe, and monitors whether the RAR is transmitted within the window time interval as indicated by reference numeral 2c-20. The scheduling information of the RAR is represented by the RA-RATI of the PDCCH. The RA-RNTI is triggered using the position of the radio resource on the time and frequency axis for transmitting the preamble. The RAR includes a timing advance command, a UL grant, and a temporary C-RNTI.

[0146] As shown in reference numeral 2c-25, if RAR is successfully received in the RAR window, msg 3 is transmitted using the information of UL grant included in RAR. msg 3 includes different information depending on the purpose of random access. The following [Table 2] is an example of information carried on msg 3.

[0147] [Table 2]

[0148]

[0149] If RAR is received in the nth subframe, msg3 is transmitted in the n+6th subframe. HARQ is applied to msg 3 and thereafter. As shown in the reference numeral 2c-30, after msg 3 transmission, the UE drives a specific timer and monitors a contention resolution (CR) message before the timer process. The CR message includes an RRC connection establishment message or an RRC connection reestablishment message depending on the purpose of random access and a CR MAC CE.

[0150] Figure 2d The process of selecting the SI request method based on msg 1 or the SI request method based on msg-3 according to the present disclosure is shown.

[0151] To request system information other than the minimum SI, the UE uses random access. The UE requests the network for system information that the UE wishes to receive through msg 1 (preamble) or msg 3. In step 2d-05, the UE determines whether PRACH resource information that can be used for SI request is included in the periodically broadcast minimum SI.

[0152] The PRACH resource information may include preamble ID (or index) information (prach-ConfigIndex) for SI request and radio resource information for sending the preamble. If the minimum SI includes this information, the UE may request system information other than the minimum SI through msg 1 for SI request in step 2d-10. Otherwise, the UE requests system information other than the minimum SI through msg3 in step 2d-15. At this time, the UE sends a preamble for general random access.

[0153] Figure 2e The SI request process based on msg-3 according to the present disclosure is shown.

[0154] In step 2e-15, UE 2e-05 receives minimum SI from network 2e-10. In step 2e-20, UE triggers a request for system information other than minimum SI. In step 2e-25, UE determines whether dedicated preamble information for SI request is included in the minimum SI. In step 2e-30, if dedicated preamble information is not included, UE requests SI through msg 3.

[0155] In step 2e-35, the UE sends a preamble to the network. The preamble is not necessarily a preamble of an SI request. In step 2e-40, the UE receives a random access response message of the preamble from the network. In step 2e-45, the UE sends msg3 to the network. msg 3 includes information indicating which type of SI message or SIB the UE requests.

[0156] In addition, the configured MAC CE varies according to the RRC state of the UE. When the UE is in connected mode, msg 3 includes C-RNTI MAC CE and MAC CE with SI request information (hereinafter referred to as SI request MAC CE). C-RNTI MAC CE includes C-RNTI information for indicating that the UE in the cell is in connected mode. Although the size of C-RNTI MAC CE in LTE technology is 2 bytes, in the next generation mobile communication system, the size may be larger.

[0157] When the UE is in idle mode or inactive mode, msg 3 includes UE ID MAC CE and SI request MAC CE. UE ID MAC CE includes UE ID information for indicating that the UE in the cell is in idle mode or inactive mode. UE ID information is used to determine whether the message corresponds to msg 3 sent by the UE when the UE receives the msg-4 message.

[0158] When the UE is in connected mode, the network receiving msg 3 sends msg 4 scheduled with C-RNTI to the UE. When the UE is in idle mode or inactive mode, the network receiving msg 3 sends msg 4 including UE ID MAC CE and SI request MAC CE to the UE, wherein the UE ID MAC CE and SI request MAC CE are included in msg 3.

[0159] Figure 2f The method of configuring the SI request MAC CE in the present disclosure is shown.

[0160] The SI request MAC CE has a variable size depending on the number of SI messages or SIBs requested. Each bit is mapped to the SI message or SIB to be requested. The UE configures the corresponding bit to "1" and notifies the network which SI message or SIB is requested. In addition, as shown in the figure mark 2f-05, a bit in a specific position can be used to indicate whether all SI messages or SIBs except the minimum SI are requested.

[0161] Figure 2g A method for configuring UE ID MAC CE in the present disclosure is shown.

[0162] UE ID MAC CE2g-05 has the same size as C-RNTI MAC CE and includes a random value generated by the UE or a value from the UE ID. UE ID MAC CE includes UE ID information for indicating that the UE in the cell is in idle mode or inactive mode. UE ID information is used to determine whether the UE corresponds to msg 3 sent by the UE when it receives msg-4 message.

[0163] Figure 2h A method for configuring a UE contention resolution identifier included in msg 4 according to the present disclosure is shown.

[0164] When the UE requests SI in idle mode or inactive mode, the UE contention resolution identification MAC CE 2h-05 is included in msg 4 which is a response message to msg 3. The information contained in the MAC CE having a fixed size is the UE ID CE and the SI request MAC CE included in msg 3 or only the UE ID MAC. When both the UE ID MAC CE and the SI request MAC CE are included, the UE contention resolution identification MAC CE may be exceeded due to the variable size of the SI request MAC CE, in which case the exceeded information is not included in the MAC CE. When only the UE ID MAC CE is included, the size of the UE contention resolution identification MAC CE is limited to be the same as the UE ID MAC CE.

[0165] Figure 2i is a flow chart illustrating the operation of a UE according to the present disclosure.

[0166] In step 2i-05, the UE receives the minimum SI. The minimum SI does not include the msg 1 configuration information for SI request. In step 2i-10, the UE triggers the SI request process through msg 3. In step 2i-15, the UE selects a preamble. In step 2i-20, the UE sends the selected preamble.

[0167] In step 2i-25, the UE receives a random access response message corresponding to the preamble from the eNB. In step 2i-30, the UE sends msg 3 to the eNB using the scheduling information included in the response message. When the UE is in connected mode, C-RNTI MAC CE and S1 request MAC CE are included in msg 3. When the UE is in idle mode or inactive mode, UE ID MAC CE and S1 request MAC CE are included in msg 3.

[0168] In step 2i-35, the UE receives msg 4. The UE receives msg 4 scheduled with C-RNTI when the UE is in connected mode, and receives msg 4 including both UE ID MAC CE and SI request MAC CE or only UE ID MAC CE when the UE is in idle mode or inactive mode. In step 2i-40, the UE receives the requested system information.

[0169] Figure 2j A process of handling a case where general random access and SI request random access overlap with each other in the present disclosure is shown.

[0170] In the present disclosure, when general random access and SI request random access overlap each other, general random access is performed first. Necessary system information related to network connection may be included in the minimum SI, and the remaining system information may be obtained by UE request. Therefore, when random access for connecting to the network is triggered, SI request is performed first instead of random access.

[0171] In step 2j-15, UE 2j-05 receives minimum SI from source gNB 2j-10. The minimum SI may include PRACH radio resource information for SI request. In step 2j-20, the UE triggers a request for system information other than the minimum SI. In step 2j-25, the UE determines whether the preamble information dedicated to the SI request is included in the minimum SI. If the preamble information is included, SI is requested using the SI request dedicated preamble. In step 2j-30, if the preamble information is not included, the UE requests SI through msg 3. In step 2j-35, if the SI request procedure is triggered, or during the execution of the procedure, the UE determines whether general random access is triggered by the following reasons.

[0172] * Idle mode to connected mode transition: RRC connection request

[0173] *RRC connection reestablishment: RRC connection reestablishment request

[0174] *HO Complete: RRC connection reconfiguration completed

[0175] *DL data recovery: PDCCH command

[0176] *UL data recovery: trigger BSR

[0177] In step 2j-40, when general random access is triggered, the UE stops the triggered or executing SI request procedure and starts general random access. The UE sends a preamble for general random access to the network.

[0178] Figure 2k is a flowchart illustrating an operation of a UE when a general random access and an SI request random access overlap with each other in the present disclosure.

[0179] In step 2k-05, the UE receives minimum SI from the eNB. The minimum SI may include PRACH radio resource information for SI request. In step 2k-10, the UE triggers a request for system information other than the minimum SI. In step 2k-15, if the SI request procedure is triggered, or during the SI request procedure, the UE determines whether general random access is triggered by the following reasons.

[0180] * Idle mode to connected mode transition: RRC connection request

[0181] *RRC connection reestablishment: RRC connection reestablishment request

[0182] *HO Complete: RRC connection reconfiguration completed

[0183] *DL data recovery: PDCCH command

[0184] *UL data recovery: trigger BSR

[0185] In step 2k-20, if general random access is triggered, the UE stops the triggered SI request procedure or the triggered SI request procedure being executed, and starts general random access.

[0186] Figure 2l The structure of the UE is shown.

[0187] refer to Figure 2l , the UE includes a radio frequency (RF) processing unit 2l-10, a baseband processing unit 2l-20, a storage unit 2l-30 and a controller 2l-40.

[0188] The RF processing unit 21-10 performs functions of sending and receiving signals through a wireless channel, such as frequency band conversion and amplification of the signal. That is, the RF processing unit 21-10 up-converts the baseband signal provided by the baseband processing unit 21-20 into an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 21-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Although Figure 2l Only one antenna is shown, but a UE may include multiple antennas.

[0189] In addition, the RF processing unit 21-10 may include multiple RF chains. In addition, the RF processing unit 21-10 may perform beamforming. For beamforming, the RF processing unit 21-10 may control the phase and size of each signal sent / received through multiple antennas or antenna elements. The RF processing unit 21-10 may perform MIMO and receive multiple layers during MIMO operation.

[0190] The baseband processing unit 21-20 performs the function of performing conversion between baseband signals and bit streams according to the physical layer standard of the system. For example, when transmitting data, the baseband processing unit 21-20 generates complex symbols by encoding and modulating the transmission bit stream. In addition, in data reception, the baseband processing unit 21-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 21-10. For example, in an orthogonal frequency division multiplexing (OFDM) scheme, when sending data, the baseband processing unit 21-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion.

[0191] In addition, in data reception, the baseband processing unit 2l-20 divides the baseband signal provided from the RF processing unit 2l-10 in units of OFDM symbols, reconstructs the signal mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then reconstructs the received bit stream through demodulation and decoding.

[0192] The baseband processing unit 21-20 and the RF processing unit 21-10 send and receive signals as described above. Therefore, the baseband processing unit 21-20 and the RF processing unit 21-10 can be referred to as a transmitter, a receiver, a transceiver or a communication unit. In addition, at least one of the baseband processing unit 21-20 and the RF processing unit 21-10 may include multiple communication modules to support multiple different radio access technologies.

[0193] In addition, at least one of the baseband processing unit 21-20 and the RF processing unit 21-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., IEEE802.11) and cellular networks (e.g., LTE). In addition, different frequency bands may include super high frequency (SHF) (e.g., 2.5 GHz and 2 GHz) bands and millimeter (mm) wave (e.g., 60 GHz) bands.

[0194] The storage unit 21-30 stores data such as basic programs, application programs, and setting information for UE operation. Specifically, the storage unit 21-30 may store information related to a second access node that performs wireless communication via a second radio access technology. The storage unit 21-30 provides the stored data in response to a request from the controller 21-40.

[0195] The controller 21-40 controls the overall operation of the UE. For example, the controller 21-40 sends and receives signals through the baseband processing unit 21-20 and the RF processing unit 21-10. In addition, the controller 21-40 records data in the storage unit 21-40 and reads data. To this end, the controller 21-40 may include at least one processor. For example, the controller 21-40 may include a communication processor (CP) that performs communication control and an application processor (AP) that controls a higher layer such as an application.

[0196] Figure 2m is a block diagram of a MeNB in ​​a wireless communication system according to an embodiment of the present disclosure.

[0197] like Figure 2m As shown in , the eNB includes an RF processing unit 2m-10, a baseband processing unit 2m-20, a backhaul communication unit 2m-30, a storage unit 2m-40 and a controller 2m-50.

[0198] The RF processing unit 2m-10 performs functions of sending and receiving signals through a wireless channel, such as frequency band conversion and amplification of the signal. That is, the RF processing unit 2m-10 up-converts the baseband signal provided by the baseband processing unit 2m-20 into an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 2m-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although Figure 2m Only one antenna is shown, but the first access node may include multiple antennas.

[0199] In addition, the RF processing unit 2m-10 may include multiple RF chains. The RF processing unit 2m-10 may perform beamforming. For beamforming, the RF processing unit 2m-10 may control the phase and size of each of the signals sent and received through multiple antennas or antenna elements. The RF processing unit 2m-10 may perform downlink MIMO operations by sending one or more layers.

[0200] The baseband processing unit 2m-20 performs the function of performing conversion between baseband signals and bit streams according to the physical layer standard of the radio access technology. For example, in data transmission, the baseband processing unit 2m-20 generates complex symbols by encoding and modulating the transmission bit stream. In addition, in data reception, the baseband processing unit 2m-20 reconstructs the received bit string by demodulating and decoding the baseband signal provided from the RF processing unit 2m-10. For example, in the OFDM scheme, when sending data, the baseband processing unit 2m-20 can generate complex symbols by encoding and modulating the transmission bit stream, mapping the complex symbols to subcarriers, and then configuring OFDM symbols through IFFT operation and CP insertion.

[0201] In addition, in data reception, the baseband processing unit 2m-20 divides the baseband signal provided from the RF processing unit 2m-10 in units of OFDM symbols, reconstructs the signal mapped to the subcarrier by FFT operation, and then reconstructs the received bit stream by demodulation and decoding. The baseband processing unit 2m-20 and the RF processing unit 2m-10 transmit and receive signals as described above. Therefore, the baseband processing unit 2m-20 and the RF processing unit 2m-10 can be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0202] The backhaul communication unit 2m-30 provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit 2m-30 converts a bit stream sent from the MeNB to another node (e.g., SeNB or core network) into a physical signal, and converts a physical signal received from other nodes into a bit stream.

[0203] The storage unit 2m-40 stores basic programs, application programs, and data such as configuration information for the operation of the MeNB. Specifically, the storage unit 2m-40 may store information related to the bearer assigned to the accessed UE and measurement results reported from the accessed UE. In addition, the storage unit 2m-40 may store information that is a reference for determining whether to allow or interrupt multiple accesses to the UE. The storage unit 2m-40 provides the stored data according to a request from the controller 2m-50.

[0204] The controller 2m-50 controls the overall operation of the MeNB. For example, the controller 2m-50 sends and receives signals through the baseband processing unit 2m-20 and the RF processing unit 2m-10 or through the backhaul communication unit 2m-30. In addition, the controller 2m-50 records data in the storage unit 2m-40 and reads data. To this end, the controller 2m-50 may include at least one processor.

[0205] <Third Embodiment>

[0206] In the following description, for the convenience of description, terms used to identify access nodes, terms related to network entities, terms related to messages, terms related to interfaces between network entities, and terms related to various identification information are used. Therefore, the present disclosure is not limited by the terms provided below, and other terms representing the subject matter with equivalent technical meanings may be used.

[0207] For convenience of description, the present disclosure uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard and the LTE Advanced (LTE-A) standard, which are the latest standards in existing communication standards. However, the present disclosure is not limited to the terms and names, and may be equally applied to a system according to another standard. Specifically, the present disclosure may be applied to 3GPP New Radio (NR, the fifth generation mobile communication standard).

[0208] Figure 3a The structure of the LTE system described with reference to the present disclosure is shown.

[0209] refer to Figure 3a , the wireless communication system includes multiple ENBs 3a-05, 3a-10, 3a-15 and 3a-20, a mobile management entity (MME) 3a-20 and a serving gateway (S-GW) 3a-30. A user equipment (hereinafter, referred to as a UE or terminal) 3a-35 accesses an external network through the ENBs 3a-05, 3a-10, 3a-15 and 3a-20 and the S-GW 3a-30.

[0210] ENBs 3a-05, 3a-10, 3a-15, and 3a-20 provide radio access to UEs accessing the network as access nodes of the cellular network. That is, in order to serve user traffic, ENBs 3a-05, 3a-10, 3a-15, and 3a-20 perform scheduling based on collected status information (such as the buffer status of the UE, the available transmission power status, and the channel status), and support connections between the UE and the core network (CN).

[0211] The MME 3a-25 is a device that performs mobility management and various control functions of the UE and is connected to a plurality of ENBs, and the S-GW 3a-30 is a device that provides data bearers. The MME 3a-25 and the S-GW 3a-30 also perform authentication and bearer management of UEs accessing the network, and process packets received from the ENBs 3a-05, 3a-10, 3a-15, and 3a-20 or packets to be transmitted to the ENBs 3a-05, 3a-10, 3a-15, and 3a-20.

[0212] Figure 3b The wireless protocol structure of the LTE system described with reference to the present disclosure is shown. The structure of the NR defined below can be used with Figure 3b The wireless protocol structure in is different, but in the present disclosure, for convenience, the wireless protocol structure will be described.

[0213] refer to Figure 3b, the UE and ENB include packet data convergence protocol (PDCP) 3b-05 and 3b-40, radio link control (RLC) 3b-10 and 3b-35, and medium access control (MAC) 3b-15 and 3b-30 respectively in the wireless protocol of the LTE system.

[0214] Packet Data Convergence Protocol (PDCP) 3b-05 and 3b-40 perform operations of compressing / rebuilding IP headers, and Radio Link Control (RLC) 3b-10 and 3b-35 reconfigure PDCP packet data units (PDUs) to have an appropriate size. MAC 3b-15 and 3b-30 are connected to various RLC layer devices included in one UE, and perform operations for multiplexing RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs.

[0215] The PHY layers 3b-20 and 3b-25 perform operations for channel coding and modulating high-layer data to generate OFDM symbols, and perform operations for transmitting OFDM symbols through a radio channel or demodulating and channel decoding OFDM symbols received through a radio channel and transmitting the demodulated and channel-decoded OFDM symbols to a higher layer. In addition, the PHY layer uses hybrid ARQ (HARQ) to correct additional errors, and the receiving side transmits 1-bit information indicating whether a packet sent by the transmitting side is received. The 1-bit information is called HARQ ACK / NACK information.

[0216] Downlink HARQ ACK / NACK information for uplink transmission may be transmitted through a Physical Hybrid ARQ Indicator Channel (PHICH), and uplink HARQ ACK / NACK information for downlink transmission may be transmitted through a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

[0217] Meanwhile, the PHY layer may include one or more frequencies / subcarriers, and a technique in which one eNB configures and uses multiple frequencies simultaneously is called carrier aggregation (CA). CA significantly increases the amount of transmission by the number of self-carriers by additionally using a primary carrier and one or more secondary carriers, which exceeds conventional techniques in which only one subcarrier is used for communication between a UE and an E-UTRAN NodeB (eNB).

[0218] Meanwhile, in LTE, a cell within an eNB that uses a primary carrier is called a primary cell (PCell), and a cell that uses a secondary carrier is called a secondary cell (SCell). A technique obtained by extending the CA function to two eNBs is called dual connectivity (DC). In DC, a UE is simultaneously connected to and uses a primary E-UTRAN NodeB (MeNB) and a secondary E-UTRAN NodeB (SENB), and a cell belonging to the MeNB is called a primary cell group (MCG) and a cell belonging to the SeNB is called a secondary cell group (SCG).

[0219] Each cell group has a representative cell, and the representative cell of the primary cell group is called a primary cell (PCell) and the representative cell of the secondary cell group is called a primary secondary cell (PSCell). When using NR, MCG uses LTE technology and SCG uses NR, and UE can use LTE and NT at the same time.

[0220] Although not shown, a radio resource control (RRC) layer exists above the PDCP layer of each of the UE and the eNB, and the RRC layer can send and receive configuration control messages related to access and measurement to control radio resources. For example, the measurement can be indicated to the UE through an RRC layer message, and the UE can report the measurement result to the eNB through an RRC layer message.

[0221] Figure 3c The concept of dual connectivity is shown.

[0222] When using DC, the UE can be connected to and use two eNBs simultaneously. Figure 3c In the example, UE 3c-05 is connected to macro eNB 3c-00 using LTE technology and simultaneously connected to small cell eNB 3c-10 using NR technology, and sends and receives data. This is called E-UTRAN NR Dual Connectivity (EN-DC).

[0223] The macro eNB is called the master E-UTRAN NodeB (MeNB), and the small cell eNB is called the secondary 5G NodeB (SeNB). There may be multiple small cells in the service area of ​​the MeNB, and the MeNB is connected to the SgNB through a wired backhaul network 3c-15. The set of service cells provided from the MeNB is called the master cell group (MCG) 3c-20, and one service cell in the MCG must be a primary cell (PCell) 3c-25 with all functions performed by existing cells (such as connection establishment, connection reconstruction, and switching).

[0224] In the PCell, the uplink control channel has a PUCCH. A serving cell other than the PCell is referred to as a secondary cell (SCell) 3c-30. Figure 3c A scenario is shown where the MeNB provides one SCell and the SgNB provides three SCells. The set of serving cells provided by the SgNB is called a secondary cell group (SCG) 3c-40.

[0225] When the UE receives data from two eNBs and sends data to the two eNBs, the MeNB provides the SgNB with commands for adding, changing, and removing serving cells provided by the SgNB. To send commands, the MeNB may configure the UE to measure serving cells and neighboring cells. The UE shall report the measurement results to the MeNB according to the configuration information.

[0226] In order to effectively transmit and receive data to and from the UE by the SgNB, a service cell that plays a similar role to the PCell of the MCG is required, and the service cell is referred to as the primary SCell (PSCell) in the present disclosure. One service cell in the SCG is determined to be the PSCell, and the PSCell has the PUCCH as an uplink control channel. The PUCCH is used when the UE sends HARQ ACK / NACK information, channel state information (CSI), and scheduling request (SR) to the eNB.

[0227] Figure 3d An example of a message flow between a UE and an eNB when the UE starts measuring different types of RATs in a state where eNBs using multiple RATs proposed by the present disclosure coexist.

[0228] exist Figure 3d In step 3d-11, UE 3d-01 in idle mode (RRC_IDLE) accesses the LTE cell due to generating data to be sent. In idle mode, the UE is not connected to the network to save the power of the UE, so the UE cannot send data. In order to send data, the UE needs to switch to connected mode (RRC_CONNECTED). When the UE successfully accesses the LTE cell 3d-03, the UE switches to connected mode (RRC_CONNECTED), and the UE in connected mode can send data to the LTE cell and receive data from the LTE cell through security activation and data bearer configuration.

[0229] Thereafter, in step 3d-13, the eNB configures the measurement of the cells adjacent to the UE in the UE. The measurement configuration may include a measurement object (measObject), a report configuration, a measurement start condition, and measurement interval information for other frequency measurements.

[0230] The measurement object may include information indicating which frequency is to be measured, and the frequency information may include LTE frequency. If the UE supports NR or supports DC with NR, NR frequency may be included. The eNB may configure multiple measurement objects in the UE.

[0231] The reporting configuration may include a configuration for periodically reporting the measurement result to the eNB or reporting the measurement result to the eNB when the following conditions are met.

[0232] Event A1 (when the serving cell measurement result is better than the threshold)

[0233] Event A2 (when the serving cell measurement result is worse than the threshold)

[0234] Event A3 (the neighbor cell measurement result is better than the primary cell (PCell) (the representative cell when the UE uses multiple serving cells) measurement result by an offset or more)

[0235] Event A4 (the measurement result of the neighboring cell is better than the threshold)

[0236] Event A5 (the PCell measurement result is worse than threshold 1 and the neighboring cell measurement result is better than threshold 2)

[0237] Event A6 (the case where the neighbor cell measurement result is better than the secondary cell (SCell) (the remaining cells except the PCell when the UE uses multiple serving cells) measurement result by an offset or more)

[0238] The eNB may configure multiple reporting configurations in the UE.

[0239] The eNB groups the measurement objects and the report configurations and manages them by the measurement identifier. For example, when the eNB configures three measurement objects (e.g., frequencies X, Y, and Z) and two report configurations (e.g., report configuration 1: periodic report and report configuration 2: conditional report A3) in the UE, the eNB may map the report identifier 1 to the frequency X and report configuration 1 and map the report identifier 2 to the frequency Y and report configuration 2, and configure them in the UE.

[0240] The measurement start condition (s-Measure) is a threshold. When the signal strength of the PCell in the serving cell is higher than the measurement start condition, the UE determines that the signal strength of the currently accessed cell is good enough and does not measure the neighboring cells. By configuring the measurement start condition, the UE does not measure the neighboring cells unnecessarily, thereby reducing the power consumption of the UE.

[0241] At the same time, in the state of EN-DC, even if the channel state of LTE PCell is good, it may be better not to stop measuring NR neighboring cells. For example, if the UE uses LTE PCell and then adds an NR cell to the SCG (i.e., NR SCell addition), even if the channel state of PCell is good, it may be preferable to continuously measure the NR cell and add the NR cell to the NR SCG in time. In another example, if there is an NR cell (providing a good transmission rate) near the UE while the UE uses LTE PCell, it may be preferable to perform switching to the corresponding NR cell in a timely manner when switching is possible. Therefore, for the exemplary scenario, the present disclosure includes additional information in addition to s-Measure. For example, three schemes can be considered for the additional information.

[0242] Solution 1: Each measurement object (measObject) includes an indicator

[0243] Even when the signal strength of PCell is higher than the configured s-Measure, the measurement object (frequency) included in the indicator is measured.

[0244] Solution 2: Second s-Measure (applicable only to NR)

[0245] When the second s-Measure is configured, the second s-Measure is used to determine whether the measurement belongs to the SCG (e.g., NR) or the frequency configured by the SCG.

[0246] In this case, when EN-DC is configured in the UE, the second s-Measure is included in the measurement configuration information configured by the NR SCG.

[0247] Solution 3: Indicator included in common measurement configuration information

[0248] In this case, the corresponding indicator is generally applied to frequencies using a predetermined RAT technology (eg, NR).

[0249] The eNB may send various measurement configurations to the UE via an RRC connection reconfiguration message of the RRC layer. Thereafter, in step 3d-15, the UE sends a confirmation message of the configuration indication, in which case the UE may use an RRC connection reconfiguration completion message of the RRC layer.

[0250] In step 3d-17, the UE that receives the measurement configuration information measures the same frequency as the frequency of the current serving cell (intra-frequency), different frequencies (inter-frequency), and frequencies used by different types of RATs (inter-RAT) according to the configuration information, and determines whether to perform reporting.

[0251] At this time, the UE performs the following operations according to each scheme.

[0252] If the UE receives the configuration of the indicator for each frequency according to Scheme 1, and the signal strength (reference signal received power (RSRP)) of the PCell is less than the configured s-Measure value, the UE measures the neighboring cells according to the configuration information. However, if the RSRP of the PCell is higher than the configured s-Measure value, the UE does not measure the frequency that does not include the indicator, but measures the frequency that includes the indicator.

[0253] If the UE receives the configuration of the second s-Measure value according to Scheme 2 and the signal strength of the PCell is less than the existing s-Measure (referred to as the first s-Measure), the UE starts measuring the frequencies used by RATs other than NR (e.g., LTE, UMTS, and GSM). When the signal strength of the PCell is higher than the first s-Measure, the UE does not measure the frequencies used by RATs other than NR (e.g., LTE, UMTS, and GSM). At the same time, when the signal strength of the PCell is less than the second s-Measure, the UE starts measuring NR, and when the signal strength of the PCell is higher than the second s-Measure, the UE does not measure NR.

[0254] In another embodiment, although not in Figure 3d , but the second s-Measure value can be configured by SCG (SgNB) 3d-05. That is, in a state where the SCG is added to the UE, the measurement information can be directly configured by the SCG, and at this time, a second s-Measure value can be included. In this case, the UE determines whether to use the first s-Measure to measure the frequency configured to be measured by the MCG, and determines whether to use the second s-Measure value to measure the frequency configured to be measured by the SCG (or the frequency using the same RAT as the RAT used by the SCG).

[0255] When the UE receives the configuration of the predetermined indicator commonly included in the measurement configuration information according to scheme 3, if the signal strength (reference signal received power (RSRP)) of the PCell is less than the configured s-Measure value, the UE measures the neighboring cell according to the configuration information. However, if the RSRP of the PCell is higher than the configured s-Measure value, the UE measures the frequency using a separately indicated or pre-specified RAT (e.g., NR), but does not measure other RATs and LTE frequencies.

[0256] According to the rule, the UE measures the neighboring cells. When the configured reporting configuration is met, the UE generates a measurement report message in step 3d-19 and sends the measurement report message to the eNB in ​​step 3d-21. The eNB receiving the measurement report message can determine whether to add the reported cell to the SCell or perform a handover to the reporting cell based on the content contained in the measurement report message. For example, by comparing the signal strength of the current (LTE) PCell with the signal strength of the neighboring NR cell (with a predetermined offset for normalizing the bandwidth difference), the eNB can determine whether to add the NR cell to the SCG or perform a handover.

[0257] When the UE supports DC and the eNB decides to add the NR cell to the SCG for the UE based on the determination, the eNB sends SCG information in step 3d-25 to configure the DC function to the UE. The SCG configuration information may include addition and release information of the SCell added to the SCG. The SCG configuration information may be sent using the RRC connection reconfiguration message of the RRC layer.

[0258] Thereafter, the UE may send a confirmation message indicating reception of the configuration information, and may send a message using an RRC connection reconfiguration complete message in step 3d-27. Therefore, the UE may use both the LTE cell 3d-03 as the MCG and the NR cell 3d-05 as the SCG to simultaneously send and receive data in steps 3d-29 and 3d-31.

[0259] Figure 3e is a flowchart showing the operation of a UE when the present disclosure is applied.

[0260] exist Figure 3e In step 3e-01, it is assumed that the UE is connected to the LTE eNB and is therefore in connected mode (RRC_CONNECTED).

[0261] Thereafter, in step 3e-03, the UE receives the measurement configuration of the neighboring cells from the eNB. The measurement configuration may include a measurement object (measObject), a report configuration, a measurement start condition, and measurement interval information for other frequency measurements.

[0262] The measurement object may include information indicating which frequency is to be measured, and the frequency information may include LTE frequency. If the UE supports NR or supports DC with NR, NR frequency may be included. The configuration information may include multiple measurement objects.

[0263] The reporting configuration may include a configuration for periodically reporting the measurement result to the eNB or reporting the measurement result when the following conditions are met.

[0264] Event A1 (when the serving cell measurement result is better than the threshold)

[0265] Event A2 (when the serving cell measurement result is worse than the threshold)

[0266] Event A3 (the neighbor cell measurement result is better than the primary cell (PCell) (the representative cell when the UE uses multiple serving cells) measurement result by an offset or more)

[0267] Event A4 (the measurement result of the neighboring cell is better than the threshold)

[0268] Event A5 (the PCell measurement result is worse than threshold 1 and the neighboring cell measurement result is better than threshold 2)

[0269] Event A6 (the neighbor cell measurement result is better than the secondary cell (SCell) (the remaining cells except the PCell when the UE uses multiple serving cells) measurement result by an offset or more)

[0270] Additionally, the configuration information may include multiple report configurations.

[0271] The configuration information may include configuration information for grouping measurement objects and report configuration according to measurement identifiers.

[0272] The measurement start condition (s-Measure) is a threshold. When the signal strength of the PCell in the serving cell is higher than the measurement start condition, the UE determines that the signal strength of the currently accessed cell is good enough and does not measure the neighboring cells. By configuring the measurement start condition, the UE does not measure the neighboring cells unnecessarily, thereby reducing the power consumption of the UE.

[0273] At the same time, in the state of EN-DC, even if the channel state of LTE PCell is good, it may be better not to stop measuring NR neighboring cells. For example, if the UE uses LTE PCell and then adds an NR cell to the SCG (i.e., NR SCell addition), even if the channel state of PCell is good, it may be preferable to continuously measure the NR cell and add the NR cell to the NR SCG in time. In another example, if there is an NR cell (providing a good transmission rate) near the UE while the UE uses LTE PCell, it may be preferable to perform switching to the corresponding NR cell in time when switching is possible. Therefore, for the exemplary scenario, the present disclosure includes additional information in addition to s-Measure. For example, three schemes can be considered for the additional information.

[0274] Solution 1: Include indicators for each measurement object (measObject)

[0275] In the case where the measurement object includes the indicator or even when the signal strength of PCell is higher than the configured s-Measure, measurement is performed.

[0276] Solution 2: Second s-Measure (applicable only to NR)

[0277] When the second s-Measure is configured, the second s-Measure is used to determine whether the measurement belongs to the SCG (e.g., NR) or the frequency configured by the SCG.

[0278] In this case, when EN-DC is configured in the UE, the second s-Measure is included in the measurement configuration information configured by the NR SCG.

[0279] Solution 3: Indicator commonly included in measurement configuration information

[0280] In this case, the corresponding indicator is generally applied to frequencies using a predetermined RAT technology (eg, NR).

[0281] The UE may receive various measurement configurations via an RRC connection reconfiguration message of the RRC layer. Thereafter, the UE sends a confirmation message of the configuration indication, in which case the UE may use an RRC connection reconfiguration complete message of the RRC layer.

[0282] In step 3e-05, the UE receiving the measurement configuration information measures the same frequency as the frequency of the current serving cell (intra-frequency), different frequencies (inter-frequency), and frequencies used by different types of RATs (inter-RAT) according to the configuration information, and determines whether to provide a report.

[0283] At this time, the UE performs the following operations according to each scheme.

[0284] If the UE receives the configuration of the indicator for each frequency according to Scheme 1, and the signal strength (reference signal received power (RSRP)) of the PCell is less than the configured s-Measure value, the UE measures the neighboring cells according to the configuration information. However, if the RSRP of the PCell is higher than the configured s-Measure value, the UE does not measure the frequency that does not include the indicator, but measures the frequency that includes the indicator.

[0285] If the UE receives the configuration of the second s-Measure value according to Scheme 2 and the signal strength of the PCell is less than the existing s-Measure (referred to as the first s-Measure), the UE starts measuring the frequencies used by other RATs (e.g., LTE, UMTS, and GSM) except NR. When the signal strength of the PCell is higher than the first s-Measure, the UE does not measure the frequencies used by other RATs (e.g., LTE, UMTS, and GSM) except NR. At the same time, when the signal strength of the PCell is less than the second s-Measure, the UE starts measuring NR, and when the signal strength of the PCell is higher than the second s-Measure, the UE does not measure NR.

[0286] Although Figure 3e Another embodiment is not shown, but the second s-Measure value may be configured by the SCG (SgNB). That is, in a state where the SCG is added to the UE, the measurement information may be directly configured by the SCG, in which case the second s-Measure value may be included. In this case, the UE determines whether to measure the frequency configured to be measured by the MCG using the first s-Measure, and determines whether to measure the frequency configured to be measured by the SCG (or the frequency using the same RAT as the RAT used by the SCG) using the second s-Measure value.

[0287] When the UE receives the configuration of the predetermined indicator commonly included in the measurement configuration information according to scheme 3, when the signal strength (reference signal received power (RSRP)) of the PCell is less than the configured s-Measure value, the UE measures the neighboring cell according to the configuration information. However, if the RSRP of the PCell is higher than the configured s-Measure value, the UE measures the frequency using a separately indicated or pre-specified RAT (e.g., NR), but does not measure other RATs and LTE frequencies.

[0288] According to the rule, the UE measures neighboring cells. When the configured report configuration is met in step 3e-07, the UE generates a measurement report message and sends the measurement report message to the eNB in ​​step 3e-09.

[0289] Thereafter, according to the report from the eNB, the UE may receive SCG information and configure the DC function or receive an instruction to switch to the corresponding cell in step 3e-11. The SCG configuration information may include addition and release information of the SCell added to the SCG. The SCG configuration information may be sent using an RRC connection reconfiguration message of the RRC layer.

[0290] Thereafter, the UE may send a confirmation message indicating reception of the configuration information, and may send the message using an RRC connection reconfiguration complete message. In addition, in the case of a handover, a confirmation message may be sent to the mobile cell. Therefore, when DC is configured in the UE, the UE may send and receive data using both MCG and SCG at the same time.

[0291] Figure 3f is a block diagram illustrating a UE according to an embodiment of the present disclosure.

[0292] refer to Figure 3f , the UE includes a radio frequency (RF) processing unit 3f-10, a baseband processing unit 3f-20, a storage unit 3f-30 and a controller 3f-40.

[0293] The RF processing unit 3f-10 performs functions of sending and receiving signals through a wireless channel, such as frequency band conversion and amplification of the signal. That is, the RF processing unit 3f-10 up-converts the baseband signal provided by the baseband processing unit 3f-20 into an RF band signal, transmits the RF band signal through an antenna, and then down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 3f-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Although Figure 3f Only one antenna is shown in the figure, but the UE may include multiple antennas.

[0294] The RF processing unit 3f-10 may include multiple RF chains. In addition, the RF processing unit 3f-10 may perform beamforming. For beamforming, the RF processing unit 3f-10 may control the phase and size of each signal sent / received through multiple antennas or antenna elements.

[0295] The baseband processing unit 3f-20 performs the function of converting between baseband signals and bit streams according to the physical layer standard of the system. For example, in data transmission, the baseband processing unit 3f-20 generates complex symbols by encoding and modulating the transmission bit string. In data reception, the baseband processing unit 3f-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 3f-10. For example, in an orthogonal frequency division multiplexing (OFDM) scheme, when sending data, the baseband processing unit 3f-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion.

[0296] In addition, in data reception, the baseband processing unit 3f-20 divides the baseband signal provided from the RF processing unit 3f-10 into units of OFDM symbols, reconstructs the signal mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then reconstructs the received bit stream through demodulation and decoding.

[0297] The baseband processing unit 3f-20 and the RF processing unit 3f-10 send and receive signals as described above. Therefore, the baseband processing unit 3f-20 and the RF processing unit 3f-10 may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. In addition, at least one of the baseband processing unit 3f-20 and the RF processing unit 3f-10 may include different communication modules to process signals in different frequency bands. The different frequency bands may include super high frequency (SHF) (e.g., 2.5 GHz and 5 GHz) bands and millimeter (mm) wave (e.g., 60 GHz) bands.

[0298] The storage unit 3f-30 stores data such as basic programs, application programs, and setting information for UE operation.

[0299] The controller 3f-40 controls the overall operation of the UE. For example, the controller 3f-40 sends and receives signals through the baseband processing unit 3f-20 and the RF processing unit 3f-10. In addition, the controller 3f-40 records data in the storage unit 3f-30 and reads the data. To this end, the controller 3f-40 may include at least one processor. For example, the controller 3f-40 may include a communication processor (CP) that performs communication control and an application processor (AP) that controls a higher layer such as an application. According to an embodiment of the present disclosure, the controller 3f-40 includes a multi-connection processing unit 3f-42 for performing processing in a multi-connection mode. For example, the controller 3f-40 may control the UE to perform Figure 3e The operation process of the UE is shown in FIG.

[0300] According to an embodiment of the present disclosure, the UE receives a message from the eNB for indicating measurement. The controller receiving the message determines whether to start measurement, perform measurement, and generates a corresponding measurement result report message when the measurement starts and the report configuration is met, and sends the measurement result report message to the eNB according to the configuration of the measurement event and condition received from the eNB.

[0301] The methods recited in the claims and / or the specification according to various embodiments may be implemented by hardware, software, or a combination of hardware and software.

[0302] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors in an electronic device. At least one program may include instructions that cause an electronic device to execute the method according to various embodiments of the present disclosure as defined by the attached claims and / or the disclosure herein.

[0303] The program (software module or software) may be stored in a non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disk-ROM (CD-ROM), digital versatile disk (DVD) or other types of optical storage devices or tape cassettes. Alternatively, any combination of some or all of them may form a memory storing the program. In addition, a plurality of such memories may be included in an electronic device.

[0304] In addition, the program can be stored in an attachable storage device that can access the electronic device through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), and a storage area network (SAN) or a combination thereof. Such a storage device can access the electronic device via an external port. In addition, a separate storage device on a communication network can access the portable electronic device.

[0305] In the above detailed embodiments of the present disclosure, the components included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiments presented. However, for ease of description, singular or plural expression is selected to be suitable for the proposed situation, and the present disclosure is not limited to single or multiple elements. Elements expressed in plural form can be configured as single, or elements expressed in singular form can be configured as multiple.

[0306] Meanwhile, although the present disclosure has been shown and described with reference to the specific embodiments of the present disclosure in the detailed description of the present disclosure, it is self-evident that various changes in form and details may be made in the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: receiving first configuration information about measurement from a first base station of a first radio access technology RAT, the first configuration information comprising first information about a first threshold for identifying whether to perform measurement and second information about a measurement object; identifying a RAT of a frequency to be measured based on the second information; In a case where the identified RAT of the frequency is a first RAT, identifying based on the first information whether a reference signal received power RSRP of a primary cell PCell for the first base station is less than the first threshold, and performing measurement for the frequency of the first RAT based on the RSRP being less than the first threshold; and In a case where the identified RAT of the frequency is a second RAT, based on the second RAT being indicated in the second information, measurement is performed on the frequency of the second RAT.

2. The method according to claim 1, further comprising: receiving, from a second base station using a second RAT, second configuration information related to measurement of at least one cell of the second base station, The first base station operates as the main cell group MCG of the terminal, and the second base station operates as the secondary cell group SCG of the terminal based on dual connection DC.

3. The method according to claim 2, further comprising: performing measurement of the at least one cell based on third information related to the second threshold in the second configuration information, The measurement of the at least one cell is performed based on that the RSRP of the primary secondary cell PSCell of the second base station is less than the second threshold.

4. The method according to claim 1, in, The first threshold is not applied to measurements of frequencies for the second RAT.

5. The method according to claim 1, wherein: The first RAT is Long Term Evolution (LTE) and the second RAT is New Radio (NR).

6. A terminal in a wireless communication system, the terminal comprising: Transceiver; as well as The controller is configured as: controlling the transceiver to receive first configuration information about measurement from a first base station of a first radio access technology RAT, the first configuration information comprising first information about a first threshold for identifying whether to perform measurement and second information about a measurement object; identifying a RAT of a frequency to be measured based on the second information; In a case where the identified RAT of the frequency is a first RAT, identifying based on the first information whether a reference signal received power RSRP of a primary cell PCell for the first base station is less than the first threshold, and performing measurement for the frequency of the first RAT based on the RSRP being less than the first threshold; and In a case where the identified RAT of the frequency is a second RAT, based on the second RAT being indicated in the second information, measurement is performed on the frequency of the second RAT.

7. The terminal according to claim 6, wherein: The controller is further configured to control the transceiver to receive second configuration information related to measurement of at least one cell of the second base station from a second base station using a second RAT, The first base station operates as the main cell group MCG of the terminal, and the second base station operates as the secondary cell group SCG of the terminal based on dual connection DC.

8. The terminal according to claim 7, wherein: The controller is further configured to perform measurement of the at least one cell based on third information related to the second threshold in the second configuration information, The measurement of the at least one cell is performed based on that the RSRP of the primary secondary cell PSCell of the second base station is less than the second threshold.

9. The terminal according to claim 6, wherein: The first threshold is not applied to measurements of frequencies for the second RAT.

10. The terminal according to claim 6, wherein: The first RAT is Long Term Evolution (LTE) and the second RAT is New Radio (NR).

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