Method and apparatus for communication in next generation mobile communication system

A method performed by a terminal according to the disclosure may comprise: receiving configuration information related to a measurement including measurement object information, wherein the measurement object information including a frequency of a synchronization signal block (SSB) and a measurement timing configuration information of the SSB; determining a reference cell to which the measurement timing configuration information of the SSB is applied based on a type of a signaling radio bearer (SRB) for which the configuration information is provided; measuring the SSB on the frequency of the SSB based on the reference cell and the measurement timing configuration information of the SSB; and transmitting a measurement report including a measurement result of the SSB on the frequency of the SSB.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. 119 from Korean Patent Application No. 10-2019-0013777 filed on Feb. 1, 2019 in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND

The disclosure relates to the operation of a terminal and a base station in a mobile communication system. The disclosure relates to a method and an apparatus for providing synchronization signal (SS)/physical broadcast channel (PBCH) block configuration information in a next-generation mobile communication system. In addition, the disclosure relates to a method and an apparatus for performing a cell measurement operation in order to minimize power consumption by a terminal in a next-generation mobile communication system. Further, the disclosure relates to a method and an apparatus for reporting a measurement result by a terminal supporting dual connectivity in a next-generation mobile communication system.

2. Description of Related Art

SUMMARY

An aspect of the disclosure is to provide a method and an apparatus for providing SS/PBCH block configuration information in a next-generation mobile communication system. Another aspect of the disclosure is to provide a method and an apparatus for performing a cell measurement operation in order to minimize power consumption by a terminal in a next-generation mobile communication system. Another aspect of the disclosure is to provide a method and an apparatus for reporting a measurement result by a terminal supporting dual connectivity in a next-generation mobile communication system.

An embodiment may provide a method performed by a terminal, the method comprising: receiving configuration information related to a measurement including measurement object information, wherein the measurement object information includes a frequency of a synchronization signal block (SSB) and a measurement timing configuration information of the SSB; determining a reference cell to which the measurement timing configuration information of the SSB is applied based on a type of a signaling radio bearer (SRB) for which the configuration information is provided; measuring the SSB on the frequency of the SSB based on the reference cell and the measurement timing configuration information of the SSB; and transmitting a measurement report including a measurement result of the SSB on the frequency of the SSB.

Further, an embodiment may provide a terminal comprising: a transceiver; and a controller configured to: receive, via the transceiver, configuration information related to a measurement including measurement object information, wherein the measurement object information includes a frequency of a synchronization signal block (SSB) and a measurement timing configuration information of the SSB, determine a reference cell to which the measurement timing configuration information of the SSB is applied based on a type of a signaling radio bearer (SRB) for which the configuration information is provided, measure the SSB on the frequency of the SSB based on the reference cell and the measurement timing configuration information of the SSB, and transmit, via the transceiver, a measurement report including a measurement result of the SSB on the frequency of the SSB.

Still, further, an embodiment may provide a method performed by a base station, the method comprising: transmitting, to a terminal configured with a dual connectivity (DC), configuration information related to a measurement including measurement object information, wherein the measurement object information includes a frequency of a synchronization signal block (SSB) and a measurement timing configuration information of the SSB; receiving, from the terminal, a measurement report including a measurement result of the SSB on the frequency of the SSB, wherein the measurement result is obtained based on a measurement of the SSB on the frequency of the SSB according to a reference cell and the configuration information, and wherein the reference cell to which the measurement timing configuration information of the SSB is applied is determined based on a type of a signaling radio bearer (SRB) for which the configuration information is provided.

Still, further, an embodiment may provide a terminal comprising: a transceiver; and a controller configured to: transmit, to a terminal configured with a dual connectivity (DC) via the transceiver, configuration information related to a measurement including measurement object information, wherein the measurement object information includes a frequency of a synchronization signal block (SSB) and a measurement timing configuration information of the SSB, and receive, from the terminal via the transceiver, a measurement report including a measurement result of the SSB on the frequency of the SSB, wherein the measurement result is obtained based on a measurement of the SSB on the frequency of the SSB according to a reference cell and the configuration information, and wherein the reference cell to which the measurement timing configuration information of the SSB is applied is determined based on a type of a signaling radio bearer (SRB) for which the configuration information is provided.

The technical subjects pursued in the disclosure may not be limited to the above mentioned technical subjects, and other technical subjects which are not mentioned may be clearly understood, through the following descriptions, by those skilled in the art of the disclosure.

According to embodiments of the disclosure, it is possible to provide a method and an apparatus for providing SS/PBCH block configuration information in a next-generation mobile communication system. In addition, according to embodiments of the disclosure, it is possible to provide a method and an apparatus for performing a cell measurement operation in order to minimize power consumption by a terminal in a next-generation mobile communication system. Further, according to embodiments of the disclosure, it is possible to provide a method and an apparatus for reporting a measurement result by a terminal supporting dual connectivity in a next-generation mobile communication system.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the disclosure will be described in detail with reference to the accompanying drawings. Here, it is noted that identical reference numerals denote the same structural elements in the accompanying drawings. Further, a detailed description of well-known functions and configurations incorporated herein will be omitted when it makes the subject matter of the disclosure rather unclear.

In a description of embodiments of the disclosure, a description of technologies that are already known to those skilled in the art and are not directly relevant to the disclosure is omitted. Such an omission of unnecessary descriptions is intended to prevent obscuring of the main idea of the disclosure and more clearly transfer the main idea.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. In addition, the size of each component does not fully reflect the actual size, and the same or corresponding components in the drawings are given the same reference numeral.

However, the disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms. The embodiments are provided to completely disclose the disclosure and fully convey the scope of the disclosure to those skilled in the art, and the disclosure is to be defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

First Embodiment

A first embodiment relates to a method and an apparatus for providing synchronization signal (SS)/physical broadcast channel (PBCH) block configuration information in a next-generation mobile communication system.

FIG. 1AAillustrates a diagram of the structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 1AA, a radio access network of a next-generation mobile communication system {new radio (NR)} includes a new radio node B (hereinafter, referred to as a “gNB”)1aa-10, an access and mobility management entity (AMF)1aa-05(a new radio core network), as shown in the drawing. A new radio user equipment (hereinafter, referred to as an “NR UE” or a “terminal”)1aa-15accesses an external network through the gNB1aa-10and the AMF1aa-05.

InFIG. 1AA, the gNB1aa-10corresponds to an evolved node B (eNB) of an existing LTE system. The gNB1aa-10is connected to the NR UE1aa-15through a radio channel (1aa-20), and may provide services superior to those of the existing node B. In the next-generation mobile communication system, since all user traffic is served through a shared channel, a device for collecting status information, such as buffer status, available transmission power status, and channel status of UEs, and performing scheduling is required. The gNB1aa-10serves as such a device. One gNB typically controls multiple cells. In order to realize super-high data rates compared to existing LTE systems, the next-generation mobile communication system may have a bandwidth equal to or greater than the maximum bandwidth of existing systems, may use, as a radio access technique, orthogonal frequency division multiplexing (hereinafter, referred to as “OFDM”), and may further employ a beamforming technique in addition thereto. In addition, an adaptive modulation and coding (hereinafter, referred to as “AMC”) scheme is applied to determine a modulation scheme and a channel coding rate in accordance with the channel status of a terminal.

The AMF1aa-05performs functions such as mobility support, bearer configuration, and quality-of-service (QoS) configuration. The AMF1aa-05is a device that performs various control functions, as well as a mobility management function for a terminal, and is connected to a plurality of base stations. In addition, the next-generation mobile communication system may interwork with an existing LTE system, and the AMF1aa-05is connected to the MME1aa-25through a network interface. The MME1aa-25is connected to the eNB1aa-30, which is an existing base station. A terminal supporting LTE-NR dual connectivity may transmit/receive data to/from the eNB1aa-30while maintaining a connection to the eNB1aa-30, as well as the gNB1aa-10(1aa-35).

FIGS. 1AB and 1ACillustrate an example of configuring NR-DC. As shown in the drawing, a radio access network of a next-generation mobile communication system {new radio (NR)} may include new radio node Bs (hereinafter, referred to as “gNB s”)1ab-10,1ab-30,1ac-10, and1ac-30, AMFs1ab-05,1ab-25, and1ac-05, and a new radio core network. New radio user equipment (hereinafter, referred to as “NR UE” or a “terminals”)1ab-15or1ac-15accesses an external network through the gNBs1ab-10and1ac-10and the AMFs1ab-05and1ac-05.

FIGS. 1AA, 1AB, and 1AC, the situation in which a macro cell and a pico cell are mixed may be considered. The macro cell is controlled by a macro base station and provides services over a relatively large area. On the other hand, the pico cell is controlled by a secondary base station {e.g., a secondary eNB (SeNB) or a secondary gNB (SgNB)} and typically provides services in a much smaller area than the macro cell. Although there is no strict criterion for distinguishing between the macro cell and the pico cell, for example, it may be assumed that the macro cell has an area of about 500 m in radius and the pico cell has an area of about several tens m in radius. In the embodiments, the pico cell will be used interchangeably with a small cell. Here, the macro cell may be an LTE base station (MeNB) or an NR base station (MgNB), and the pico cell may be an NR base station (SgNB) or an LTE base station (SeNB). In particular, a 5G base station supporting the pico cell may use a frequency band of 6 GHz or more.

In the embodiments, the situation in which the macro cell and the pico cell are mixed may be considered. The macro cell is controlled by a macro base station and provides service over a relatively large area. In this case, the macro cell may include an LTE base station (MeNB) and an LTE base station (SeNB). In another embodiment, the macro cell may include an LTE base station (MeNB) and an NR base station (SgNB). In another embodiment, the macro cell may include an NR base station (MgNB) and an LTE base station (SeNB). In another embodiment, the macro cell may include an NR base station (MgNB) and an NR base station (SgNB).

Both a 4G system (LTE) and a 5G system are based on orthogonal frequency-division multiplexing (OFDM). LTE has a fixed subcarrier spacing (SCS) of 15 kHz, whereas the 5G system may support a plurality of subcarrier spacings (SCS) (e.g., 7.5 kHz, 15 kHz, 30 kHz, 60 kHz, 120 kHz, etc.) in order to provide various services such as enhanced mobile broad band (eMBB), ultra-reliable low-latency communications (URLLC), massive machine-type communication (mMTC), and the like, and provide wireless communication in various frequency ranges (e.g., sub-6 GHz, above-6 GHz, etc.). In addition, the 5G system may allow a plurality of SCSs to be subject to time division multiplexing (TDM) or frequency division multiplexing (FDM) even within one carrier. In addition, the maximum bandwidth of one component carrier (CC) is assumed to be 20 MHz in LTE, whereas it may be considered to be up to 1 GHz in the 5G system.

Therefore, in the case of the 5G system, radio resources having different SCSs may be frequency-division-multiplexed or time-division-multiplexed. A subframe is assumed as a basic unit of scheduling in LTE, but a slot having 14 symbols may be assumed as a basic unit of scheduling in the 5G system. That is, the absolute time of a subframe is fixed to 1 ms in LTE, but the length of a slot may differ depending on the SCS in the 5G system.

In particular, in 3GPP, an SS/PBCH (physical broadcast channel) block has been defined with respect to the synchronization signal (SS) used in the initial access procedure. The SS/PBCH block may include at least a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH. In addition, the SS/PBCH block may always be transmitted in the order of the PSS, the SSS, and the PBCH. In addition, the SCS of the SS/PBCH block may be transmitted using a frequency of 15 kHz, 30 kHz, 120 kHz, or 240 kHz depending on the frequency band thereof. More specifically, an SCS having 15 kHz or 30 kHz may be transmitted in a frequency band of 6 GHz or less, and an SCS having 120 kHz or 240 kHz may be transmitted in a frequency band of more than 6 GHz. In addition, the above-described frequency bands may be classified in more detail, and then an SS/PBCH block configured as a single SCS may be transmitted for each frequency band.

In addition, several SS/PBCH blocks may be transmitted in a single operation band. This is intended to enable the terminals with various capabilities to coexist and operate within a system bandwidth. In this case, although the system bandwidth is increased, the location of the SS/PBCH block received by the terminal may vary depending on the network configuration. In addition, the transmission time of the SS/PBCH block may also vary depending on the network configuration. In addition, the transmission interval of the SS/PBCH blocks may not be constant.

The details of the DC described with reference toFIGS. 1AB and 1ACmay be applied to a second embodiment and a third embodiment of the disclosure.

FIG. 1AD(a) illustrates a diagram describing bandwidth adaptation technology in accordance with various embodiments,FIG. 1AD(b) illustrates a diagram describing bandwidth adaptation technology in accordance with various embodiments,FIG. 1AD(c) illustrates a diagram describing bandwidth adaptation technology in accordance with various embodiments, andFIG. 1AEillustrates a diagram describing bandwidth adaptation technology in accordance with various embodiments.

Referring toFIGS. 1AD(a) to AD(c), a base station may provide information on a bandwidth part (hereinafter, also referred to as a “BWP”) associated with carrier bandwidth. The terminal may receive information on the BWP from the base station. According to various embodiments, the information on the BWP may include bandwidth part configuration information. According to an embodiment, the bandwidth part configuration information may include configuration values necessary for the terminal to use the bandwidth of a transmission signal as a bandwidth part. For example, the bandwidth part configuration information may include the frequency resource position of the BWP, the bandwidth of a frequency resource of the BWP, and numerology information associated with the operation of the BWP. According to an embodiment, the numerology information of the BWP may include at least one of subcarrier spacing (SCS) information, the type of cyclic prefix (e.g., a normal cyclic prefix or an extended cyclic prefix) of orthogonal frequency division multiplexing (OFDM), and the number of symbols included in a single slot (e.g., 7 symbols or 14 symbols). According to various embodiments, the terminal may activate at least one BWP, based on the bandwidth part configuration information received from the base station, and may transmit and receive a control signal or data, based on the activated BWP.

Referring toFIG. 1AD(a), the terminal may receive bandwidth part configuration information on one BWP610from the base station, and may activate the BWP610, based on bandwidth part configuration information on the BWP610. According to an embodiment, the BWP610may be an operation band configured based on the radio frequency (RF) performance of the terminal.

Referring toFIG. 1AD(b), the terminal may receive bandwidth part configuration information on a plurality of BWPs (e.g., BWP1622and BWP2624) from the base station. According to an embodiment, the plurality of BWPs may include a BWP (e.g., BWP1622) associated with a basic operation band configured based on the RF performance of the terminal, and may further include a BWP (e.g., BWP2624) associated with an additional operation band. According to various embodiments, there may be one or more BWPs associated with the additional operation band. According to various embodiments, the BWP associated with the additional operation band may have numerology features different from those of the basic operation band. According to various embodiments, the BWPs associated with at least two additional operation bands may have different numerology features. The terminal may select and activate one of BWP1622and BWP2624, based on the bandwidth part configuration information on BWP1622and the bandwidth part configuration information on BWP2624. According to an embodiment, the base station may instruct the terminal to select and activate one of BWP1622and BWP2624.

Referring toFIG. 1AD(c), the terminal may receive, from the base station, bandwidth part configuration information about a plurality of BWPs having different numerology features {e.g., BWP3(numerology1)632and BWP3(numerology2)634}. According to an embodiment, the plurality of BWPs may include BWP3(numerology1)632having a first numerology feature or BWP3(numerology2)634having a second numerology feature. The terminal may select and activate at least one of BWP3(numerology1)632and BWP3(numerology2)634, based on numerology information included in the bandwidth part configuration information on BWP3(numerology1)632and the bandwidth part configuration information on BWP3(numerology2)634. For example, the terminal may select and activate at least one of BWP3(numerology1)632and BWP3(numerology2)634, based on at least one of subcarrier spacing (SCS) information, the type of cyclic prefix (e.g., a normal cyclic prefix or an extended cyclic prefix) of OFDM, and the number of symbols included in a single slot (e.g., 7 symbols or 14 symbols), among numerology information included in the bandwidth part configuration information on BWP3(numerology1)632and the bandwidth part configuration information on BWP3(numerology2)634.

According to various embodiments, the terminal may select a BWP to be activated from among a plurality of BWPs, based on the reception of a radio resource control (RRC) signal from the base station, or may select a BWP to be activated based on activation/deactivation information included at least one piece of bandwidth part configuration information of the plurality of BWPs. As another example, the terminal may select a BWP to be activated based on the reception of downlink control information (DCI) from the base station. As another example, the terminal may select a BWP to be activated based on the reception of a MAC control element (MAC CE) from the base station.

In addition, according to an embodiment, in the case of using an RRC signal, the base station may include frequency resource information allocated from a network or at least one piece of BWP-related time information in the RRC signal, and may transmit the same. For example, the terminal may select and activate one of the BWPs, based on the frequency resource information allocated from a network included in the RRC signal or at least one piece of BWP-related time information included in the RRC signal. For example, the at least one piece of BWP-related time information may include a time pattern for changing the BWP. The time pattern may include operation slot information or subframe information of the BWPs or a specified operation time of the BWPs.

In addition, according to an embodiment, in the case of using bandwidth part configuration information, a bit map indicating activation/deactivation may be included in the bandwidth part configuration information of the BWPs. The terminal may select a BWP to be activated based on the bitmap. For example, the bitmap may have a value 0 or 1. The value 0 (or 1 or another specified value) may indicate activation, and the value 1 (or 0 or another specified value) may indicate deactivation. The terminal may select a BWP to be activated according to the bitmap value included in the bandwidth part configuration information of the BWPs.

In addition, according to an embodiment, in the case of using DCI, the base station may include information to activate at least one BWP in the DCI. The terminal may select a BWP to be activated from among a plurality of BWPs, based on the information included in the DCI. If the information included in the DCI is the same as the BWP (e.g., BWP1622), which is in an active state, the terminal may ignore the DCI value, and if the information included in the DCI is different from the BWP1622, which is in an active state, the terminal may switch the BWP1622in the active state to the BWP corresponding to the information included in the DCI (e.g., BWP2624) and activate the same. For example, the terminal may activate the BWP2624a predetermined time (e.g., a slot-based time or a subframe-based time) after reception of the DCI.

In addition, according to an embodiment, in the case of using DCI, an index indicating activation/deactivation may be included in the bandwidth part configuration information. The terminal may select a BWP to be activated based on the index. In an embodiment, the bandwidth part configuration information may include an index of each BWP. For example, upon receiving the DCI including an index of the BWP for activation, the terminal may activate a corresponding BWP, and may deactivate other BWPs.

In addition, according to an embodiment, in the case of using the MAC CE, the base station may include information for activating at least one BWP in the MAC CE. The terminal may select a BWP to be activated from among the plurality of BWPs, based on the information included in the MAC CE. If the information included in the MAC CE is the same as the BWP (e.g., BWP1610), which is in an active state, the terminal may ignore the information included in the MAC CE, and if the information included in the MAC CE is different from the BWP1610, which is in an active state, the terminal may switch the BWP1610in the active state to the BWP corresponding to the information included in the MAC CE (e.g., BWP2624) and activate the same. The terminal may activate the BWP2624a predetermined time (e.g., a slot-based time or a subframe-based time) after the reception of the MAC CE.

Referring toFIG. 1AE, according to various embodiments, BWPs {e.g., carrier bandwidth part0(602), carrier bandwidth part1(604), or carrier bandwidth part2(606)} may be allocated within a carrier bandwidth. According to an embodiment, the BWPs602,604, and606may be allocated based on a physical resource block (hereinafter, also referred to as a “PRB”) (e.g., PRB0601) specified in the carrier bandwidth. The PRB may be, for example, a specified bandwidth unit available to the terminal. According to an embodiment, a plurality of PRBs may be allocated to a plurality of BWPs. For example, a plurality of PRBs, such as N1 to PRB N1+a, may be allocated to carrier bandwidth part0(602); a plurality of PRBs, such as N2 to PRB N2+b, may be allocated to carrier bandwidth part1(604); and a plurality of PRBs, such as N3 to PRB N3+c, may be allocated to carrier bandwidth part2(606). For example, N1, N2, or N3 may be a start PRB, and “a”, “b”, or “c” may be the number of PRBs, that is, the number of bandwidths of the BWP.

According to various embodiments, the terminal may use a bandwidth corresponding to the entire BWP, or may use a bandwidth corresponding to one or more PRBs included in the BWP.

The details of the BWPs described with reference toFIGS. 1AD and 1AEmay also be applied to the second embodiment and the third embodiment.

FIG. 1AFillustrates a diagram of a radio protocol structure in an LTE system according to an embodiment.

Referring toFIG. 1AF, the radio protocol of an LTE system includes packet data convergence protocol (PDCP)1af-05or1af-40, radio link control (RLC)1af-10or1af-35, and medium access control (MAC)1af-15or1af-30in a terminal and an eNB, respectively. The PDCP performs operations, such as IP header compression/decompression and the like. The primary functions of the PDCP are summarized as follows.Header compression and decompression (ROHC only)Transfer of user dataIn-sequence delivery of higher-layer PDUs at PDCP re-establishment procedure for RLC AMSequence reordering {for split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception}Duplicate detection of lower-layer SDUs at PDCP re-establishment procedure for RLC AMRetransmission of PDCP SDUs at handover and, for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure, for RLC AMCiphering and decipheringTimer-based SDU discard in uplink.

The radio link control (RLC)1af-10or1af-35reconfigures a PDCP PDU (packet data unit) to an appropriate size and performs ARQ operation and the like. The primary functions of the RLC are summarized as follows.Data transfer function (transfer of higher-layer PDUs)ARQ function {error correction through ARQ (only for AM data transfer)}Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transfer)Re-segmentation of RLC data PDUs (only for AM data transfer)Reordering of RLC data PDUs (only for UM and AM data transfer)Duplicate detection (only for UM and AM data transfer)Protocol error detection (only for AM data transfer)RLC SDU discard (only for UM and AM data transfer)RLC re-establishment

The MAC1af-15or1af-30is connected to a plurality of RLC entities configured in a terminal or a base station, multiplexes RLC PDUs into MAC PDUs, and demultiplexes RLC PDUs from MAC PDUs. The primary functions of the MAC are summarized as follows.Mapping between logical channels and transport channelsMultiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channelsScheduling information reportingHARQ function (error correction through HARQ)Priority handling between logical channels of one UEPriority handling between UEs by means of dynamic schedulingMBMS service identificationTransport format selectionPadding

The physical layers1af-20and1af-25channel-code and modulate higher-layer data, and convert the same into OFDM symbols that are then transmitted through a radio channel, or demodulate OFDM symbols received through a radio channel and channel-decode the same, and then transmit the same to higher-layers.

The details of the configurations described with reference toFIG. 1AFmay also be applied to the second embodiment and the third embodiment.

FIG. 1AGillustrates a diagram of a radio protocol structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 1AG, the radio protocol of the next-generation mobile communication system includes NR service data adaption protocol (SDAP)1ag-01or1ag-45, NR PDCP1ag-05or1ag-40, NR RLC1ag-10or1ag-35, NR MAC1ag-15or1ag-30, and NR PHY1ag-20or1ag-25in a terminal and an NR base station, respectively.

The primary functions of the NR SDAP1ag-01or1ag-45may include some of the following functions.Transfer of user plane dataMapping between QoS flow and DRB for downlink and uplinkMarking QoS flow ID in both downlink and uplink packetsMapping reflective QoS flow to DRB for UL SDAP PDUs

With regard to the SDAP layer entity, the terminal may receive a configuration indicating whether or not to use a header of the SDAP layer entity or whether or not to use functions of the SDAP layer entity for each PDCP layer entity, for each bearer, or for each logical channel through a radio resource control (RRC) message. In the case where the SDAP header is configured, a 1-bit non-access stratum (NAS) reflective quality-of-service (QoS) configuration indicator and a 1-bit access stratum (AS) reflective QoS configuration indicator of the SDAP header may instruct the terminal to update or reconfigure mapping information between the QoS flow and the data bearers in uplink and downlink. The SDAP header may include QoS flow ID information indicating the QoS. The QoS information may be used as data processing priority, scheduling information, or the like in order to support effective services.

The primary functions of the NR PDCP1ag-05or1ag-40may include some of the following functions.Header compression and decompression (ROHC only)Transfer of user dataIn-sequence delivery of higher-layer PDUsOut-of-sequence delivery of higher-layer PDUsSequence reordering (PDCP PDU reordering for reception)Duplicate detection of lower-layer SDUsRetransmission of PDCP SDUsCiphering and decipheringTimer-based SDU discard in uplink

The above reordering function of the NR PDCP entity may denote a function of reordering PDCP PDUs received from a lower-layer, based on a PDCP sequence number (SN). The reordering function of the NR PDCP entity may include a function of transmitting data to a higher layer in the reordered order, may include a function of directly transmitting data to a higher-layer without consideration of the order thereof, may include a function of reordering the sequence and recording lost PDCP PDUs, may include a function of sending a status report of the lost PDCP PDUs to the transmitting end, and may include a function of making a request for retransmission of the lost PDCP PDUs.

The primary functions of the NR RLC1ag-10or1ag-35may include some of the following functions.Data transfer function (transfer of higher-layer PDUs)In-sequence delivery of higher-layer PDUsOut-of-sequence delivery of higher-layer PDUsARQ function (error correction through ARQ)Concatenation, segmentation, and reassembly of RLC SDUsRe-segmentation of RLC data PDUsReordering of RLC data PDUsDuplicate detectionProtocol error detectionRLC SDU discardRLC re-establishment

The above in-sequence delivery function of the NR RLC entity may denote a function of transferring RLC SDUs received from a lower-layer to a higher-layer in sequence. The in-sequence delivery function of the NR RLC entity may include a function of, if one original RLC SDU is divided into a plurality of RLC SDUs and received, reassembling and transmitting the same.

The in-sequence delivery function of the NR RLC entity may include a function of reordering the received RLC PDUs, based on an RLC sequence number (SN) or a PDCP sequence number (SN), may include a function of reordering the sequence and recording lost RLC PDUs, may include a function of sending a status report of the lost RLC PDUs to the transmitting end, and may include a function of making a request for retransmission of the lost RLC PDUs.

The in-sequence delivery function of the NR RLC1ag-10or1ag-35entity may include a function of, if there is a lost RLC SDU, transmitting only the RLC SDUs prior to the lost RLC SDU to a higher-layer in sequence. In addition, the in-sequence delivery function of the NR RLC entity may include a function of, if a predetermined timer expires even though there is a lost RLC SDU, transmitting all RLC SDUs received before the timer starts to a higher-layer in sequence. In addition, the in-sequence delivery function of the NR RLC entity may include a function of, if a predetermined timer expires even though there is a lost RLC SDU, transmitting all RLC SDUs received until the present to a higher-layer in sequence.

The NR RLC1ag-10or1ag-35entity may process the RLC PDUs in the order of reception, regardless of a serial number, and may transmit the same to the PDCP1ag-05or1ag-40entity in an out-of-sequence delivery manner.

In the case of receiving segments, the NR RLC1ag-10or1ag-35entity may receive the segments, which are stored in the buffer or will be received later, may reconfigure the same into one complete RLC PDU, and may transmit the complete RLC PDU to the NR PDCP entity.

The NR RLC layer may not include a concatenation function, which may be performed in the NR MAC layer or may be replaced with a multiplexing function of the NR MAC layer.

In the above description, the out-of-sequence delivery of the NR RLC entity may denote a function of directly delivering RLC SDUs received from a lower-layer to a higher-layer regardless of the sequence thereof. The out-of-sequence delivery of the NR RLC entity may include a function of, if one original RLC SDU is divided into a plurality of RLC SDUs and is received, reassembling and delivering the same. The out-of-sequence delivery of the NR RLC entity may include a function of storing and ordering RLC SNs or PDCP SNs of the received RLC PDUs, thereby recording the lost RLC PDUs.

The NR MAC1ag-15or1ag-30may be connected to a plurality of NR RLC entities configured in a single terminal, and the primary functions of the NR MAC may include some of the following functions.Mapping between logical channels and transport channelsMultiplexing/demultiplexing of MAC SDUsScheduling information reportingHARQ function (error correction through HARQ)Priority handling between logical channels of one UEPriority handling between UEs by means of dynamic schedulingMBMS service identificationTransport format selectionPadding

The NR PHY layers1ag-20and1ag-25may perform operations of channel-coding and modulating the higher-layer data into OFDM symbols and transmitting the same through a radio channel, or operations of demodulating and channel-decoding the OFDM symbols received through the radio channel and transmitting the same to the higher-layer.

The details of the configuration described with reference toFIG. 1AGmay also be applied to the second embodiment and the third embodiment.

FIGS. 1AH, 1AI, and 1AJare diagrams illustrating an example of an SS/PBCH block according to an embodiment, andFIG. 1AKis a diagram illustrating a method of transmitting an SS/PBCH block according to an embodiment.

Referring toFIG. 1AH, in a 5G system defined in 3GPP, one or more SS/PBCH blocks600may be included in an arbitrary frequency bandwidth {e.g., wide bandwidth (CC)}. In addition, the SS/PBCH block may be transmitted while including PBCHs620,640, and650, as well as a PSS610/SSS630.

The SS/PBCH block may be transmitted in the structure as shown inFIG. 1AH. The PSS610, the first PBCH620, the SSS630, and the second PBCH640are transmitted in different symbols, and a frequency of 20 RBs may be used for the transmission of the SS/PBCH block600. In addition, a portion650of the PBCH may be transmitted in the symbol for transmitting the SSS630. In addition, the PSS610, the SSS630, and the PBCHs620,640, and650may be aligned with respect to the centers thereof.

In addition, referring toFIG. 1AK, in 3GPP, it is possible to transmit the SS/PBCH block with an offset of an OFDM subcarrier grid, instead of transmitting the same to conform to an RB grid. The offset value of the subcarrier grid applied thereto may be indicated by the PBCH.

Referring back toFIG. 1AH, candidate positions, in which the SS/PBCH blocks600including four symbols are able to be transmitted, may be determined in two consecutive slots (14 symbols) of 120 kHz, as shown by reference numeral670. For reference, one slot may include 14 symbols in 3GPP. Alternatively, one slot may include 7 symbols. In addition, as illustrated by reference numeral675inFIG. 1AH, candidate positions, in which the SS/PBCH blocks600including four symbols are able to be transmitted, may be determined in four consecutive slots (14 symbols) of 240 kHz. In an embodiment, a total of 64 candidate positions for transmission of the SS/PBCH block600may be determined at a frequency above 6 GHz (240 kHz), based on the arrangement in the slot illustrated inFIG. 1AH.

In addition, the transmission pattern of the SS/PBCH block600on the time axis may be repeated for a predetermined period. The transmission pattern on the time axis may be configured such that the candidate positions, in which the SS/PBCH blocks600are able to be transmitted, are determined in a slot in 3GPP, and such that up to 64 SS/PBCH blocks (above 6 GHz, 8 for below 6 GHz) may be transmitted during the initial 5 ms. In addition, the network may determine the pattern that is actually transmitted from among these candidate positions. The above pattern may be repeated for a period of 5, 10, . . . , 160 ms, which may be determined by the base station. However, the terminal may primarily regard the repetition period of the pattern as 20 ms in the initial access procedure, thereby performing the initial access procedure.

Meanwhile, the candidate positions capable of transmitting the SS/PBCH blocks600at a frequency below 6 GHz may be the same as those illustrated inFIG. 1AI. As illustrated by reference numeral680, the positions capable of transmitting two SS/PBCH blocks600may be determined in a single slot (14 symbols) at a frequency of 15 kHz. In addition, as illustrated by reference numeral685, the positions capable of transmitting four SS/PBCH blocks600may be determined in two consecutive slots (14 symbols) at a frequency of 30 kHz.600ai,610ai,620ai,630ai, and640airefer to the corresponding configurations inFIG. 1AH.

In addition, as illustrated inFIG. 1AJ, the positions capable of transmitting up to eight SS/PBCH blocks600ajmay be determined at a frequency below 6 GHz.

In addition, the transmission pattern of the SS/PBCH block600on the time axis may be repeated for a predetermined period. The transmission pattern on the time axis may be configured such that the candidate positions capable of transmitting the SS/PBCH blocks600are determined in a slot in 3GPP, and such that up to 8 SS/PBCH blocks (above 6 GHz, 8 for below 6, and 4 for below 3) may be transmitted during the initial 5 ms. In addition, the network may determine the pattern that is actually transmitted from among these candidate positions. The above pattern may be repeated for a period of 5, 10, . . . , 160 ms, which may be determined by the base station. However, the terminal may primarily regard the repetition period of the pattern as 20 ms in the initial access procedure, thereby performing the initial access procedure.

A plurality of SS/PBCH blocks may be transmitted on the frequency axis within a frequency band operated by a single base station. In this case, the network may also determine the frequency position in which the SS/PBCH block is transmitted, and may be detected by the terminal using an interval for discovering the SS/PBCH block defined in the standard.

In the 5G system, at least one cell may exist in a frequency band operated by a single base station. One cell may be associated with one SS/PBCH block in terms of the terminal. The SS/PBCH block may be referred to as an “SS/PBCH block associated with a cell”, an “SS/PBCH block defining a cell”, a “cell-defining SS/PBCH block”, or the like, but is not limited thereto. That is, in the case where the terminal completes DL/UL synchronization and an RRC connection/NAS connection, based on the SS/PBCH block discovered in the frequency detection process, the SS/PBCH block for the corresponding cell may be referred to as a “cell-defining SS/PBCH block”.

The details of the SS/PBCH block and the transmission method described with reference toFIGS. 1AH, 1AI, and 1AJmay also be applied to the second embodiment and the third embodiment.

FIG. 1ALillustrates a diagram of a frame structure according to an embodiment.

Referring toFIG. 1AL, a plurality of sub-operation frequency bands (referred to as a “sub CC” in the disclosure) may be included in a system frequency band (wideband CC) of a base station. For example, four sub-operation frequency bands, such as sub CC1, sub CC2, sub CC3, and sub CC4, are illustrated, but the disclosure is not limited thereto, and three or fewer sub-operation frequency bands or five or more sub-operation frequency bands may be included in the operation frequency band of the base station. The sub-operation frequency band is only an example for the convenience of description, and may not be logically or physically separated in standards or actual implementations.

RF capability910, which is one of the UE capabilities, indicates the bandwidth (BW) that can be supported by the terminal using one RF. InFIG. 1AL, it is assumed that a terminal (e.g., target UE) supports three consecutive CCs (sub CC1, sub CC2, and sub CC3) through one RF. Accordingly, the operation frequency band of the terminal may be the frequency band including sub CC1, sub CC2, and sub CC3.

In addition, in the example shown inFIG. 1AL, it may be assumed that the SS/PBCH blocks are provided in sub CC1, sub CC2, and sub CC4. Further, the SS/PBCH block of sub CC2is assumed to be a cell-defining SS block of a target UE. In the example inFIG. 1AL, the base station may instruct the terminal to measure the SS/PBCH block included in sub CC1or sub CC4. In this case, the base station transmits, to the terminal, a configuration message for measurement including a frequency value {NR absolute radio-frequency channel number (NR ARFCN)} of a corresponding SS/PBCH block.

InFIG. 1AL, physical cell identity (PCID) #1, PCID #2, and PCID #3in the respective SS/PBCH blocks provided in sub CC1, sub CC2, and sub CC4may have the same value or different values. In addition, at least two PCIDs may be the same. For example, PCID #1and PCID #2of SS/PBCH block1and SS/PBCH block2in consecutive sub CC1and sub CC2may have the same value, and PCID #3of SS/PBCH block3in sub CC4may have a value different therefrom.

The frame structure according toFIG. 1ALmay also be applied to the second and third embodiments.

FIG. 1AMillustrates a diagram of an example of an initial access procedure in accordance with an embodiment. The initial access procedure may be performed in the process in which the terminal camps on the cell at the beginning when the terminal is turned on. The initial access procedure may also be performed when the PLMN is changed. Alternatively, the initial access procedure may be performed in the process in which the terminal missing the network camps on the cell again. Alternatively, the initial access procedure may be performed in the process in which the terminal in an idle state relocates and camps on the cell corresponding to the relocated area. Alternatively, the initial access procedure may be performed in the process in which the terminal in a connected state camps on a neighboring cell according to an indication of the base station or a determination of the terminal.

An initial access procedure of a terminal will be described based on the example of the system assumed inFIG. 1AL. This is a description of only one of multiple possible scenarios, and the disclosure is not limited thereto.

Referring toFIG. 1AM, in step1010, the terminal may perform energy detection, and may search for an SS/PBCH block. The terminal may search for the SS/PBCH block in the carrier frequency band using synchronization signal (SS) raster information. In this case, the SS raster information indicates the position at which the synchronization signal can be detected, and may be, for example, a global synchronization channel number (GSCN) or an NR ARFCN. Accordingly, the terminal may detect a PSS and an SSS of sub CC2in the scenario inFIG. 1AL.

According to an embodiment, the terminal may detect a plurality of SS/PBCH blocks included in a band, based on the sequence of PSSs, thereby selecting a single SS/PBCH block from among the plurality of detected SS/PBCH blocks. Information on the plurality of detected SS/PBCH blocks may be utilized in a measurement operation.

According to an embodiment, the terminal may select the SS/PBCH block having the highest correlation peak value. Alternatively, the terminal may select the SS/PBCH block having the highest SNR (signal-to-noise ratio)/RSSI (received signal strength indicator).

Meanwhile, in the case where the SS/PBCH block is transmitted through multiple beams, the terminal may select one of the SS/PBCH blocks received through an Rx beam of the terminal.

In step1020, the terminal may perform cell searching. The terminal may identify whether or not there is a cell mapped to the PSS or the SSS detected in step1010using the known PSS and SSS sequences. Accordingly, the PCID of the corresponding cell may be detected. In addition, a process of performing DL synchronization may be conducted simultaneously with this step or before or after this step.

In step1030, the terminal may perform measurement. The terminal may calculate or measure quality, based on reference signal received power (RSRP) of the selected SS/PBCH block and RSRP of the PBCH DMRS identified based on the determined PCID. This process may be performed before step1020, may be performed simultaneously with step1020, or may be performed after step1020.

In step1040, the terminal may perform decoding of the PSS/SSS and the PBCH in the SS/PBCH block detected in step1020. According to the scenario inFIG. 1AL, the terminal may perform decoding of the PSS/SSS and the PBCH in the SS/PBCH block of sub CC2.

The terminal may obtain control resource set (CORESET) information related to remaining minimum system information (RMSI) in the PBCH. The terminal may obtain RMSI data by decoding a CORESET related to the RMSI, based on the obtained information. In addition, the terminal may obtain random access channel (RACH) configuration information from the RMSI. The terminal may perform a RACH procedure, based on the RACH configuration information obtained from the RMSI. In addition, in the case where the terminal receives an RRC configuration message in MSG 4 during the RACH procedure, the RRC state of the terminal may switch to an RRC connected state.

In addition, the terminal may identify the temporal position of the SS/PBCH block transmitted from the actual network, which is included in the RRC reconfiguration message.

The terminal having switched to the RRC connected state may transmit UE capability information. The UE capability information may include bandwidth information and information about a band in which the terminal is capable of operation. In addition, the UE capability may include a time required for the terminal to process received data. More specifically, the UE capability may include time information required for the terminal to process scheduling information received for uplink data and transmit the uplink data based on the processed scheduling information. In addition, the UE capability may include a time required for the terminal to process received uplink data and transmit ACK/NACK for the downlink data, based on the same. In addition, the UE capability may include information on a combination of bands for which the terminal is capable of performing carrier aggregation. Subsequently, the operation bandwidth of the terminal may be configured as an operation bandwidth conforming to the UE RF capability through an RRC reconfiguration message. For example, referring to the scenario shownFIG. 1AL, sub CC1to sub CC3may be configured as the operation bandwidth of the terminal.

In addition, one or more bandwidth parts may be configured (at least one BWP is configured in a band including sub CC1to sub CC3of the scenario inFIG. 1AL) through an RRC reconfiguration message, and the terminal may receive an RRC reconfiguration message including information related to the neighboring cell in which the measurement is performed, for example, at least one piece of frequency and time information related to the SS/PBCH block and the CSI-RS.

The initial access procedure described in connection withFIG. 1AMmay also be applied to the second and third embodiments.

In the next-generation mobile communication system, the terminal derives reference signal received power (RSRP) from the SS/PBCH block broadcast by the next-generation base station in order to recognize the downlink channel quality. An embodiment proposes a method of determining the timing at which the SS/PBCH block is transmitted.

FIG. 1Billustrates a flowchart of a process for deriving SS/PBCH block measurement timing in NR-DC according to an embodiment.

The terminal1b-05performs a connection establishment procedure with a first NR base station1b-10and then switches to a connected mode (1b-13). The first base station consults a second NR base station1b-12, and then configures the serving cell(s) belonging to the second base station1b-12to the terminal1b-05(1b-14). At this time, the terminal1b-05is in an NR DC state in which the terminal is connected to the two NR base stations1b-10and1b-12. Here, “dual connectivity (DC)” refers to technology in which a terminal receives a wireless communication service while being connected to a plurality of base stations. The first base station1b-10is a master node (MN), and configures, to the terminal1b-05, one or more serving cells of the second base station1b-12. {i.e., a secondary node (SN)} (1b-14). If both the first base station1b-10and the second base station1b-12are NR base stations, the state may be referred to as “NR-DC”; if the first base station1b-10is an LTE base station and if the second base station1b-12is an NR base station, the state may be referred to as “EN-DC”; and if the first base station1b-10is an NR base station and if the second base station1b-12is an LTE base station, the state may be referred to as “NE-DC”.

The first base station1b-10or the second base station1b-12transmits configuration information related to cell measurement to the terminal1b-05in the connected mode through a predetermined RRC message (1b-15and1b-17). The configuration information related to cell measurement (measConfig IE) may be primarily including “measObject”, “reportConfig”, and “measId” indicating a combination of one “measObject” and one “reportConfig”. “measObject” contains information on the frequency and the cell to be measured, and “reportConfig” includes information to be applied for reporting the collected measurement information, periodic or event-based report time information, measurement information to report, and the like. “measObject”, “reportConfig”, and “measId” are configured in the form of a list, such as “measObjectToRemoveList”, “measObjectToAddModList”, “reportConfigToRemoveList”, “reportConfigToAddModList”, “measIdToRemoveList”, and “measIdToAddModList”, and are provided to the terminal1b-05. In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, “measGapSharingConfig”, and the like, is provided to the terminal1b-05.

Since an NR base station may have a plurality of SCSs of the SS/PBCH to be transmitted, “MeasObjectNR” information may indicate the SCS value of the SS/PBCH block to be measured. In addition, since several SS/PBCH blocks may be located in the operating cell, the base station is capable of informing the terminal of the frequency position of the SS/PBCH block that is to be measured by the terminal. Since an NR terminal has one or more configured BWPs, the base station is capable of configuring one or more BWPs to be measured and informing the terminal of the same. The terminal may measure the BWP, based on the information received from the base station. Alternatively, the NR terminal is capable of measuring the SS/PBCH block or the CSI-RS included in the activated BWP.

One “measObject IE” includes frequency information and SS/PBCH block measurement timing configuration information. Up to two types of SS/PBCH block measurement timing configuration information may be provided to the terminal1b-05in a connected mode. First configuration information is primary SS/PBCH measurement timing configuration, which is referred to as “SMTC1”, and second configuration information is secondary SS/PBCH measurement timing configuration, which is referred to as “SMTC2”. SMTC1 contains timing information on the SS/PBCH blocks of intra-frequency or inter-frequency cells indicated by “measObject IE”. The information is period and offset information on a measurement time interval for receiving the SS/PBCH block and duration information on the measurement time interval. SMTC2 contains timing information on the SS/PBCH blocks of cells belonging to the PCI list at the frequency indicated by “measObject IE”. The information is PCI list information and period information. The ASN.1 structures of SMTC1 and SMTC2 are shown in Table 2 below.

Upon receiving the information, the terminal1b-05stores the SMTC1 and SMTC2 information (1b-20). The terminal1b-05derives the timing of the SS/PBCH block, based on a system frame number (SFN) and a subframe of a predetermined cell, using the stored SMTC1 and SMTC2 configuration information and a predetermined equation (1b-25). The predetermined equation is expressed as follows. SMTC1 and SMTC2 are substituted into the following equation, respectively. SFN, in which the measurement time interval of each SS/PBCH block exists, satisfies the following equation.
SFN modT=(FLOOR(Offset/10))

If the period is greater than 5 subframes, the subframe in which the first SS/PBCH block of the interval is transmitted satisfies the following equation.
subframe=Offset mod 10

In the next-generation mobile communication system, the terminal may communicate with a plurality of base stations and one or more serving cells. The respective serving cells may have different SFNs and subframe timings. Therefore, it is necessary to determine the SFN and the subframe of a serving cell to be a reference based on which the timing of the SS/PBCH block is derived. In an embodiment, the cell may be determined to be a reference by the following method. The cell determined as described below is equally applicable both to SMTC1 and to SMTC2. In another embodiment, the cell determined as described below may be independently applied to SMTC1 and SMTC2.

Option 1) The SS/PBCH block timing is derived based on the SFN and the subframe of a primary cell (PCell). The PCell is not changed unless handover is established. Therefore, if the PCell is applied, it is possible to minimize the trouble of adjusting the SFN and the subframe as a reference when the serving cell is changed or released. In the case of option 1, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell, regardless of whether the terminal is connected to one base station or is in the DC state.

Option 2) The SS/PBCH block timing is derived based on the SFN and the subframe of a special cell (SpCell) of a cell group that provides SMTC configuration information. RRC managing each cell group configures cell measurement configuration in dual connectivity. In this case, if the timing is applied based on the SFN and the subframe of the SpCell acting as a central serving cell of each cell group (providing PUCCH in the cell group, providing downlink synchronization information of the cell group, etc.), it is possible to minimize the trouble of adjusting the SFN and the subframe as a reference when the serving cell is changed or released. The SpCell may be configured for each cell group, and the SpCell does not change frequently as other serving cells. The SpCell may denote a PCell in the case of a master cell group (MCG), and may denote a primary secondary cell (PSCell) in the case of a secondary cell group (SCG). In the case of option 2, if the terminal is connected to one base station, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell. If the terminal is configured in DC, the SS/PBCH timing may be derived based on the SFN and the subframe of each SpCell by recognizing the SpCell of each cell group. That is, the terminal may operate differently depending on whether the terminal is connected to one base station or establishes a DC connection with two or more base stations. Meanwhile, the cell group providing the SMTC configuration information may correspond to the cell group producing SMTC configuration information. The case in which the RRC managing each cell group configures the cell measurement configuration in dual connectivity has been described above. For example, if the SMTC configuration information produced by the SCG is transmitted to the MCG and is then transmitted from the MCG to the terminal, the timing for applying the SMTC configuration information may be determined based on the SFN and the subframe of the SCG that has produced the SMTC configuration information.

Option 3) The SS/PBCH block timing is derived based on the SFN and the subframe of the SpCell separately indicated by SMTC configuration information. The SMTC configuration information includes information indicating the SFN and the subframe of the SpCell, which is configured as a reference. If separate indication information is configured for the reference of the SMTC configuration information, previously received indication information may be valid until the next indication information is configured by the base station.

Option 4) The SS/PBCH block timing is derived based on the SFN and the subframe of the SpCell having the same frequency range (FR) according to the operation frequency of the serving cell. In an embodiment, although the reference generally follows the SFN of the PCell, in the case where the FR of the PCell and the FR of the serving cell are different from each other, the reference follows the SFN and the subframe of the SpCell operating in the same FR. In the case of option 4, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell when the terminal is connected to one base station. If the terminal establishes DC with the base stations operating in the same FR, the terminal may derive the SS/PBCH timing, based on the SFN and the subframe of the PCell. If the terminal establishes DC with the base stations operating in different FRs, the terminal may detect the base station operating as an SpCell from among the base stations operating in the FRs different from that of the PCell, and may derive the SS/PBCH timing, based on the SFN and the subframe of the corresponding base station. That is, in the case where the terminal establishes a DC connection with two or more base stations, the terminal may operate differently by recognizing the frequencies of the respective base stations.

The terminal1b-05receives the SS/PBCH during the derived measurement time interval, and derives a measurement result, such as RSRP and reference signal received quality (RSRQ), corresponding thereto (1b-30). The terminal1b-05includes the measured result in a predetermined RRC message periodically or on an event basis, and reports the same to the base stations1b-10and1b-12(1b-35).

FIG. 1Cillustrates a flowchart of the operation of a terminal for deriving SS/PBCH block measurement timing in NR-DC according to an embodiment.

In step1c-01, the terminal connects to one NR base station.

In step1c-03, the terminal receives configuration information on an NR-DC operation from the NR base station. That is, the serving cell(s) belonging to the NR base station is configured.

In step1c-05, the terminal receives and stores SMTC configuration information from two base station in the DC state.

In step1c-10, the terminal determines one serving cell providing the SFN and the subframe as a reference in order to determine the SS/PBCH block measurement timing. The serving cell is determined by applying the method described with reference to the embodiment inFIG. 1B.

In step1c-15, the terminal derives SS/PBCH block timing, based on the SFN and the subframe of the selected serving cell using SMTC1 and SMTC2 configuration information and a predetermined equation.

In step1c-20, the terminal measures the SS/PBCH block by applying each SS/PBCH block measurement timing derived through the SMTC1 and SMTC2 configuration information.

In step1c-25, the terminal reports the measured result to the base station using a predetermined RRC message.

The specific operation of the terminal is not limited thereto, and may include the operation of the terminal described with reference toFIG. 1B.

FIG. 1Dillustrates a flowchart of a process of deriving SS/PBCH block measurement timing in EN-DC (NE-DC) according to an embodiment.

The terminal1d-05performs a connection establishment procedure with a first LTE base station1d-10and then switches to a connected mode (1d-13). The first base station consults a second NR base station1d-12, and then configures the serving cell(s) belonging to the second base station1d-12to the terminal1d-05(1d-14). At this time, the terminal1d-05is in an EN-DC state in which the terminal is connected to the two base stations1d-10and1d-12. In case that an NE-DC, the first base station1d-10may be an NR base station, and the second base station1d-12may be an LTE base station. In case that an NN-DC, the first base station1d-10may be an NR base station and the second base station1d-12may be an NR base station.

The first base station1d-10or the second base station1d-12transmits configuration information related to cell measurement to the terminal1d-05in the connected mode through a predetermined RRC message (1d-15and1d-17). The configuration information related to cell measurement (measConfig IE) may be primarily including “measObject”, “reportConfig”, and “measId” indicating a combination of one “measObject” and one “reportConfig”. “measObject” contains information on the frequency and the cell to be measured, and “reportConfig” includes information to be applied for reporting the collected measurement information, periodic or event-based report time information, measurement information to report, and the like. “measObject”, “reportConfig”, and “measId” are configured in the form of a list, such as “measObjectToRemoveList”, “measObjectToAddModList”, “reportConfigToRemoveList”, “reportConfigToAddModList”, “measIdToRemoveList”, and “measIdToAddModList”, and are provided to the terminal1d-05. In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, “measGapSharingConfig”, and the like, is provided to the terminal1d-05.

Since an NR base station may have a plurality of SCSs of the SS/PBCH to be transmitted, “MeasObjectNR” information may indicate the SCS value of the SS/PBCH block to be measured. In addition, since several SS/PBCH blocks may be located in the operating cell, the base station is able to inform the terminal of the frequency position of the SS/PBCH block that is to be measured by the terminal. Since an NR terminal has one or more configured BWPs, the base station is capable of configuring one or more BWPs to be measured and informing the terminal of the same. The terminal may measure the BWP, based on the information received from the base station. Alternatively, the NR terminal is capable of measuring the SS/PBCH block or the CSI-RS included in the activated BWP.

See Table 1 for MeasObjectNR information element.

One “measObject IE” includes frequency information and SS/PBCH block measurement timing configuration information. Up to two types of SS/PBCH block measurement timing configuration information may be provided to the terminal1d-05in a connected mode. First configuration information is primary SS/PBCH measurement timing configuration, which is referred to as “SMTC1”, and second configuration information is secondary SS/PBCH measurement timing configuration, which and is referred to as “SMTC2”. SMTC1 contains timing information on the SS/PBCH blocks of intra-frequency or inter-frequency cells indicated by “measObject IE”. The information is period and offset information of a measurement time interval for receiving the SS/PBCH block and duration information of the measurement time interval. SMTC2 contains timing information of the SS/PBCH blocks of cells belonging to the PCI list at the frequency indicated by “measObject IE”. The information is PCI list information and period information. See Table 2 for the ASN.1 structures of SMTC1 and SMTC2.

Upon receiving the information, the terminal1d-05stores SMTC1 and SMTC2 information (1d-20). The terminal1d-05derives the timing of the SS/PBCH block, based on the SFN and the subframe of a predetermined cell using the stored SMTC1 and SMTC2 configuration information and a predetermined equation (1d-25). The predetermined equation is expressed as follows. SMTC1 and SMTC2 are substituted into the following equation, respectively. The SFN, in which the measurement time interval of each SS/PBCH block exists, satisfies the following equation.
SFN modT=(FLOOR(Offset/10))

If the period is greater than 5 subframes, the subframe in which the first SS/PBCH block of the interval is transmitted satisfies the following equation.
subframe=Offset mod 10

In EN-DC or NE-DC, the terminal may communicate with one or more serving cells in the NR base station. The respective serving cells may have different SFNs and subframe timings. Therefore, it is necessary to determine the SFN and the subframe of the serving cell based on which the timing of the SS/PBCH block is derived. In an embodiment, the cell as a reference may be determined by the following method. The cell determined as described below is equally applicable both to SMTC1 and to SMTC2.

Option 1) The SS/PBCH block timing is derived based on the SFN and the subframe of an NR SpCell (in the case of EN-DC). On the other hand, if MN is an NR base station and if SN is an LTE base station (in the case of NE-DC), the SS/PBCH block timing is derived based on the SFN and the subframe of an NR PCell. In the case of option 1, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell, regardless of whether the terminal is connected to one base station or is in the DC state.

Option 2) According to the type of SRB of an RRC message providing SMTC configuration information, if the SMTC configuration information is provided while being contained in an RRC message belonging to SRB1, the SS/PBCH block timing is derived based on the SFN and the subframe of the PCell. On the other hand, if the SMTC configuration information is provided while being contained in an RRC message belonging to SRB3, the SS/PBCH block timing is derived based on the SFN and the subframe of the PSCell. This option may also be applied to the EN-DC scenario, which is dual connectivity of the LTE base station and the NR base station. All RRC messages transmitted by the SN belong to SRB3 in the EN-DC. Therefore, if the SMTC configuration information contained in the RRC message belonging to the SRB3 is received, for the same reason as in option 2, the SFN and the subframe of the PSCell may be configured as a reference. In the case of option 2, in the case where the terminal is connected to one base station, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell. If the terminal is configured in DC, the SS/PBCH timing may be derived based on the SFN and the subframe of each SpCell by recognizing the SpCell of each cell group according to the configuration of the SRB providing the SMTC. That is, the terminal may operate differently depending on whether the terminal is connected to one base station or establishes a DC connection with two or more base stations. More specifically, the terminal may determine a reference cell for deriving the SS/PBCH timing, based on RRC information for configuring DC. Meanwhile, the bearer providing the SMTC configuration information may correspond to the cell group that produces the SMTC configuration information. The case in which the RRC managing each cell group configures the cell measurement configuration in the case of dual connectivity has been described above. If the SMTC configuration information is provided through an RRC message of SRB1, the application of the SMTC may follow the timing of the PCell, and if the SMTC configuration information is provided through an RRC message of SRB3, the application of the SMTC may follow the timing of the PSCell. However, in the case where the SMTC configuration information produced in the SCG is provided through SRB1 because SRB3 is not configured, the application of the SMTC may follow the timing of the PSCell.

Option 3) The SS/PBCH block timing is derived based on the SFN and the subframe of the SpCell separately indicated by SMTC configuration information. The SMTC configuration information includes information indicating the SFN and the subframe of the SpCell, which is configured as a reference. If separate indication information is configured for the reference of the SMTC configuration information, previously received indication information may be valid until the next indication information is configured by the base station.

Option 4) The SS/PBCH block timing is derived based on the SFN and the subframe of the SpCell having the same frequency range (FR) according to the operation frequency of the serving cell. In an embodiment, although the reference generally follows the SFN of the PCell, in the case where the FR of the PCell and the FR of the serving cell are different from each other, the reference follows the SFN and the subframe of the SpCell operating in the same FR. In the case of option 4, the SS/PBCH timing may be derived based on the SFN and the subframe of the PCell when the terminal is connected to one base station. If the terminal establishes DC with the base stations operating in the same FR, the terminal may derive the SS/PBCH timing, based on the SFN and the subframe of the PCell. If the terminal establishes DC with the base stations operating in different FRs, the terminal may detect the base station operating as an SpCell from among the base stations operating in the FRs different from that of the PCell, and may derive the SS/PBCH timing, based on the SFN and the subframe of the corresponding base station. That is, in the case where the terminal establishes a DC connection with two or more base stations, the terminal may operate differently by recognizing the frequencies of the respective base stations. More specifically, the terminal may determine a reference cell for deriving the SS/PBCH timing, based on the RRC information for configuration of DC.

The terminal1d-05receives the SS/PBCH during the derived measurement time interval, and derives a measurement result, such as RSRP and RSRQ, corresponding thereto (1b-30). The terminal1d-05includes the measured result in a predetermined RRC message periodically or on an event basis, and reports the same to the base stations1d-10and1d-12(1d-35).

FIG. 1Eillustrates a flowchart of the operation of a terminal for deriving SS/PBCH block measurement timing in EN-DC (NE-DC) according to an embodiment.

In step1e-01, the terminal connects to one LTE base station.

In step1e-03, the terminal receives configuration information on an EN-DC operation from the LTE base station. That is, the serving cell(s) belonging to the NR base station is configured.

In step1e-05, the terminal receives and stores SMTC configuration information from the base station.

In step1e-10, the terminal determines one serving cell providing the SFN and the subframe as a reference in order to determine the SS/PBCH block measurement timing. The serving cell is determined by applying the method described with reference to the embodiment inFIG. 1D.

In step1e-15, the terminal derives the SS/PBCH block timing, based on the SFN and the subframe of the selected serving cell using SMTC1 and SMTC2 configuration information and a predetermined equation.

In step1e-20, the terminal measures the SS/PBCH block by applying each SS/PBCH block measurement timing derived through the SMTC1 and SMTC2 configuration information.

In step1e-25, the terminal reports the measured result to the base station using a predetermined RRC message.

The specific operation of the terminal is not limited thereto, and may include the operation of the terminal described with reference toFIG. 1D.

FIG. 1Fillustrates a diagram of the configuration of a terminal according to an embodiment.

Referring toFIG. 1F, the terminal includes a radio frequency (RF) processor1f-10, a baseband processor1f-20, a storage unit1f-30, and a controller1f-40. The controller1f-40may further include a multi-connection processor1f-42.

The RF processor1f-10performs a function of transmitting and receiving a signal through a radio channel, such as band conversion and amplification of a signal. That is, the RF processor1f-10up-converts a baseband signal provided from the baseband processor1f-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor1f-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Although only one antenna is illustrated inFIG. 1F, the terminal may have a plurality of antennas. In addition, the RF processor1f-10may include a plurality of RF chains. Further, the RF processor1f-10may perform beamforming. To perform beamforming, the RF processor1f-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. In addition, the RF processor may perform MIMO, and may receive multiple layers when performing the MIMO operation.

The baseband processor1f-20performs a function of conversion between a baseband signal and a bit string according to the physical layer specification of the system. For example, in the case of data transmission, the baseband processor1f-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, upon receiving data, the baseband processor1f-20demodulates and decodes a baseband signal provided from the RF processor1f-10to thus recover reception bit strings. For example, in the case where an orthogonal frequency division multiplexing (OFDM) scheme is applied, when transmitting data, the baseband processor1f-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through an inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processor1f-20divides the baseband signal provided from the RF processor1f-10into OFDM symbol units, restores the signals mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then restores reception bit strings through demodulation and decoding.

The baseband processor1f-20and the RF processor1f-10transmit and receive signals as described above. Accordingly, the baseband processor1f-20and the RF processor1f-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, or a “communication unit”. Further, at least one of the baseband processor1f-20and the RF processor1f-10may include a plurality of communication modules in order to support a plurality of different radio access techniques. In addition, at least one of the baseband processor1f-20and the RF processor1f-10may include different communication modules to process signals in different frequency bands. For example, the different radio access techniques may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), and the like. In addition, the different frequency bands may include super-high frequency (SHF) (e.g., 2.NRHz or NRHz) bands or millimeter wave (e.g., 60 GHz) bands.

The storage unit1f-30stores data such as fundamental programs, application programs, and configuration information for the operation of the terminal. In particular, the storage unit1f-30may store information related to a second access node that performs wireless communication using a second radio access technique. In addition, the storage unit1f-30provides the stored data at the request of the control unit1f-40.

The controller1f-40controls the overall operation of the terminal. For example, the controller1f-40transmits and receives signals through the baseband processor1f-20and the RF processor1f-10. In addition, the controller1f-40records and reads data in and from the storage unit1f-30. To this end, the controller1f-40may include at least one processor. For example, the controller1f-40may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling higher-layers such as application programs.

FIG. 1Gillustrates a diagram of the configuration of a base station according to an embodiment.

As shown inFIG. 1G, the base station includes an RF processor1g-10, a baseband processor1g-20, a backhaul communication unit1g-30, a storage unit1g-40, and a controller1g-50. The controller1g-50may further include a multi-connection processor1g-52.

The RF processor1g-10performs a function of transmitting and receiving signals, such as band conversion and amplification of a signal, through a radio channel. That is, the RF processor1g-10up-converts a baseband signal provided from the baseband processor1g-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor1g-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may have a plurality of antennas. In addition, the RF processor1g-10may include a plurality of RF chains. Further, the RF processor1g-10may perform beamforming. To perform beamforming, the RF processor1g-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. The RF processor may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processor1g-20performs a function of conversion between a baseband signal and a bit string according to a physical layer specification of a first radio access technique. For example, in the case of data transmission, the baseband processor1g-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, upon receiving data, the baseband processor1g-20demodulates and decodes a baseband signal provided from the RF processor1g-10to thus recover reception bit strings. For example, in the case where an OFDM scheme is applied, when transmitting data, the baseband processor1g-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through the IFFT operation and CP insertion. In addition, when receiving data, the baseband processor1g-20divides the baseband signal provided from the RF processor1g-10into OFDM symbol units, restores the signals mapped to the subcarriers through the FFT operation, and then restores reception bit strings through demodulation and decoding. The baseband processor1g-20and the RF processor1g-10transmit and receive signals as described above. Accordingly, the baseband processor1g-20and the RF processor1g-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, a “communication unit”, or a “wireless communication unit”.

The backhaul communication unit1g-30provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit1g-30converts a bit string, transmitted from the base station to another node, such as a secondary base station, a core network, etc., into a physical signal, and converts physical signals received from other nodes into bit strings.

The storage unit1g-40stores data such as fundamental programs, application programs, and configuration information for the operation of the base station. In particular, the storage unit1g-40may store information about bearers allocated to a connected terminal, a measurement result reported from a connected terminal, and the like. In addition, the storage unit1g-40may store information that is a criterion for determining whether a multi-connection is provided to the terminal or is released. In addition, the storage unit1g-40provides the stored data in response to a request from the controller1g-50.

The controller1g-50controls the overall operation of the base station. For example, the controller1g-50transmits and receives signals through the baseband processor1g-20and the RF processor1g-10or the backhaul communication unit1g-30. In addition, the controller1g-50records and reads data in and from the storage unit1g-40. To this end, the controller1g-50may include at least one processor.

FIG. 1Hillustrates a diagram of the configuration of an electronic device according to an embodiment.FIG. 1His a block diagram $00of electronic device #01for supporting legacy network communication and 5G network communication according to various embodiments.FIG. 1Hmay be applied to the first embodiment, the second embodiment, or the third embodiment.

Referring toFIG. 1H, electronic device #01includes a first communication processor $12, a second communication processor $14, a first radio frequency integrated circuit (RFIC) $22, a second RFIC $24, a third RFIC $26, a fourth RFIC $28, a first radio frequency front end (RFFE) $32, a second RFFE $34, a third RFFE $36, a first antenna module $42, a second antenna module $44, and an antenna $48. Electronic device #01may further include a processor #20and a memory #30. A network #99may include a first network $92and a second network $94. According to another embodiment, electronic device #01may further include at least one of the components described inFIG. 1F or 1G, and the network #99may further include at least one of other networks. According to an embodiment, the first communication processor $12, the second communication processor $14, the first RFIC $22, the second RFIC $24, the fourth RFIC $28, the first RFFE $32, and the second RFFE $34may constitute at least a portion of the wireless communication module #92. According to another embodiment, the fourth RFIC $28may be omitted or included as part of the third RFIC $26.

The first communication processor $12may support establishment of a communication channel of a band to be used for wireless communication with the first network $92, and legacy network communication through the established communication channel. According to various embodiments, the first network may be a legacy network including a second generation (2G), 3G, 4G, or long-term evolution (LTE) network. The second communication processor $14may support establishment of a communication channel corresponding to a specified band (e.g., about 6 GHz to about 60 GHz), among the bands to be used for wireless communication with the second network $94, and 5G network communication through the established communication channel. According to various embodiments, the second network $94may be a 5G network defined in 3GPP. Additionally, according to an embodiment, the first communication processor $12or the second communication processor $14may support establishment of a communication channel corresponding to another specified band (e.g., about 6 GHz or below), among the bands to be used for wireless communication with the second network $94, and 5G network communication through the established communication channel. According to an embodiment, the first communication processor $12and the second communication processor $14may be implemented in a single chip or a single package. According to various embodiments, the first communication processor $12or the second communication processor $14may be provided in a single chip or a single package together with the processor #20, the coprocessor #23, or the communication module #90.

In the case of transmission, the first RFIC $22may convert the baseband signal generated by the first communication processor $12into a radio frequency (RF) signal of about 700 MHz to about 3 GHz used in the first network $92(e.g., a legacy network). In the case of reception, an RF signal may be obtained from the first network $92(e.g., a legacy network) through an antenna (e.g., a first antenna module $42), and may be preprocessed through an RFFE (e.g., the first RFFE $32). The first RFIC $22may convert the preprocessed RF signal into a baseband signal so as to be processed by the first communication processor $12.

When transmitting a signal, the second RFIC $24may convert a baseband signal generated by the first communication processor $12or the second communication processor $14into the RF signal of a Sub 6 band (e.g., about 6 GHz or less) (hereinafter, referred to as a “5G Sub-6 RF signal”) used in the second network $94(e.g., a 5G network). When receiving a signal, a 5G Sub-6 RF signal may be obtained from the second network $94(e.g., a 5G network) through an antenna (e.g., the second antenna module $44), and may be preprocessed through an RFFE (e.g., the second RFFE $34). The second RFIC $24may convert the preprocessed 5G Sub-6 RF signal into a baseband signal so as to be processed by the corresponding communication processor of the first communication processor $12or the second communication processor $14.

The third RFIC $26may convert a baseband signal generated by the second communication processor $14into an RF signal of a 5G Above-6 band (e.g., about 6 GHz to about 60 GHz) (hereinafter, referred to as a “5G Above-6 RF signal”) to be used in the second network $94(e.g., a 5G network). When receiving a signal, the 5G Above-6 RF signal may be obtained from the second network $94(e.g., a 5G network) through an antenna (e.g., the antenna $48), and may be preprocessed through the third RFFE $36. The third RFIC $26may convert the preprocessed 5G Above-6 RF signal into a baseband signal so as to be processed by the second communication processor $14. According to an embodiment, the third RFFE $36may be configured as a part of the third RFIC $26.

According to an embodiment, electronic device #01may include a fourth RFIC $28separately from the third RFIC $26or as at least a part thereof. In this case, the fourth RFIC $28may convert the baseband signal generated by the second communication processor $14into an RF signal (hereinafter, referred to as an “IF signal”) in an intermediate frequency band (e.g., about 9 GHz to about 11 GHz), and may transmit the IF signal to the third RFIC $26. The third RFIC $26may convert the IF signal into a 5G Above-6 RF signal. When receiving a signal, the 5G Above-6 RF signal may be received from the second network $94(e.g., a 5G network) through an antenna (e.g., the antenna $48), and may be converted to an IF signal by the third RFIC $26. The fourth RFIC $28may convert the IF signal into a baseband signal so as to be processed by the second communication processor $14.

According to an embodiment, the first RFIC $22and the second RFIC $24may be implemented as a single chip or at least a part of a single package. According to an embodiment, the first RFFE $32and the second RFFE $34may be implemented as a single chip or at least a part of a single package. According to an embodiment, at least one of the first antenna module $42or the second antenna module $44may be omitted, or may be combined with another antenna module, thereby processing RF signals of a plurality of corresponding bands.

According to an embodiment, the third RFIC $26and the antenna $48may be disposed on the same substrate, thereby configuring the third antenna module $46. For example, the wireless communication module #92or the processor #20may be disposed on a first substrate (e.g., a main PCB). In this case, the third RFIC $26may be disposed on a portion (e.g., a lower surface) of the second substrate (e.g., a sub-PCB) separately from the first substrate, and the antenna $48may be disposed in another portion (e.g., an upper surface) thereof, thereby configuring the third antenna module $46. According to an embodiment, the antenna $48may include an antenna array that can be used, for example, in beamforming. It is possible to reduce the length of the transmission line between the third RFIC $26and the antenna $48by arranging the same on the same substrate. This may reduce, for example, the loss (e.g., attenuation) of a signal of a high-frequency band (e.g., about 6 GHz to about 60 GHz) used in a 5G network communication, which is caused due to the transmission line. As a result, electronic device #01may improve the quality or speed of communication with the second network $94(e.g., a 5G network).

The second network $94(e.g., a 5G network) may operate independently of the first network $92(e.g., a legacy network) {for example, a stand-alone (SA) network}, or may operate while being connected thereto {for example, a non-stand-alone (NSA) network}. For example, the 5G network may have only an access network {e.g., 5G radio access network (RAN) or a next-generation RAN (NG RAN)}, and may have no core network {e.g., a next-generation core (NGC)}. In this case, electronic device #01may access the access network of the 5G network, and may then access an external network (e.g., the Internet) under the control of the core network {e.g., an evolved packed core (EPC)} of the legacy network. Protocol information for communication with a legacy network (e.g., LTE protocol information) or protocol information for communication with a 5G network {e.g., new radio (NR) protocol information} may be stored in the memory $30, so that other components (e.g., the processors #20, the first communication processor $12, or the second communication processor $14) may access the memory.

Second Embodiment

A second embodiment relates to a method and an apparatus for performing a cell measurement operation in order to minimize power consumption by a terminal in a next-generation mobile communication system.

FIG. 2AAillustrates a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 2AA, a radio access network of a next-generation mobile communication system {new radio (NR)} includes a new radio node B (hereinafter, referred to as a “gNB”)2aa-10, an AMF2aa-05, and a new radio core network, as shown in the drawing. A new radio user equipment (hereinafter, referred to as an “NR UE” or a “terminal”)2aa-15accesses an external network through the gNB2aa-10and the AMF2aa-05.

InFIG. 2AA, the gNB2aa-10corresponds to an evolved node B (eNB) of an existing LTE system. The gNB2aa-10is connected to the NR UE2aa-15through a radio channel2aa-20, and may provide services superior to those of the existing node B. In the next-generation mobile communication system, since all user traffic is served through a shared channel, a device for collecting status information, such as buffer status, available transmission power status, and channel status of UEs, and performing scheduling is required. The gNB2aa-10serves as such a device. One gNB typically controls multiple cells. In order to realize super-high data rates compared to the existing LTE system, the next-generation mobile communication system may have a bandwidth equal to or greater than the maximum bandwidth of the existing system, may use, as a radio access technique, orthogonal frequency division multiplexing (hereinafter, referred to as “OFDM”), and may further employ a beamforming technique in addition thereto. In addition, an adaptive modulation and coding (hereinafter, referred to as “AMC”) scheme is applied to determine a modulation scheme and a channel coding rate in accordance with the channel status of a terminal.

The AMF2aa-05performs functions such as mobility support, bearer configuration, and quality-of-server (QoS) configuration. The AMF2aa-05is a device that performs various control functions, as well as a mobility management function for a terminal, and is connected to a plurality of base stations. In addition, the next-generation mobile communication system may interwork with an existing LTE system, and the AMF2aa-05is connected to the MME2aa-25through a network interface. The MME2aa-25is connected to the eNB2aa-30, which is an existing base station. A terminal2aa-15supporting LTE-NR dual connectivity may transmit/receive data to/from the eNB2aa-30while maintaining the connection to the eNB2aa-30, as well as the gNB2aa-10(2aa-35).

For the definition and system configuration of the NR-DC, reference is to be made to the description made with reference toFIGS. 1AB and 1ACin the first embodiment. For the configuration of a BWP, reference is to be made to the description made with reference toFIGS. 1AE and 1ADin the first embodiment.

One of the reasons for measuring the neighbor cells and reporting the same to the base station is to support mobility of the terminal. If the signal quality of the current serving cell deteriorates, and if the signal quality of a neighboring cell becomes good, the base station instructs the terminal to perform handover to the neighboring cell. On the other hand, if the signal quality of the current serving cell is excellent, the operation of measuring the neighbor cell merely increases the power consumption by the terminal. Accordingly, the disclosure proposes a method of pausing the operation of measuring neighboring cells in consideration of dual connectivity technology, in order to reduce power consumption by the terminal, if a current serving cell provides a signal of a predetermined strength or more. In the disclosure, the above operation is called an “s-measure operation”. The s-measure operation is limited to the NR frequency and cell.

FIG. 2ABillustrates a diagram of a radio protocol structure in an LTE system according to an embodiment.

Referring toFIG. 2AB, the radio protocol of an LTE system may include a packet data convergence protocol (PDCP)2ab-05or2ab-40, a radio link control (RLC)2ab-10or2ab-35, and a medium access control (MAC)2ab-15or2ab-30in a terminal and an eNB, respectively. The PDCP performs operations, such as IP header compression/decompression and the like. For the primary functions of the PDCP, the RLC, and the MAC, reference is to be made toFIG. 1AFin the first embodiment.

FIG. 2ACillustrates a diagram of a radio protocol structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 2AC, the radio protocol of the next-generation mobile communication system includes NR service data adaption protocol (SDAP)2ac-01or2ac-45, NR PDCP2ac-05or2ac-40, NR RLC2ac-10or2ac-35, NR MAC2ac-15or2ac-30, and NR PHY2ac-20or2ac-25in a terminal and an NR base station, respectively. For the primary functions of the NR PDCP, the NR RLC, and the NR MAC, reference is to be made toFIG. 1AGin the first embodiment.

For the configuration of the SS block and the method of transmitting the SS block, reference is to be made to the configuration described with reference toFIGS. 1AH, 1AI, 1AJ, and 1AKof the first embodiment. For the frame structure, reference is to be made to the configuration described with reference toFIG. 1ALof the first embodiment. For the initial access procedure, reference is to be made to the configuration described with reference toFIG. 1AMof the first embodiment.

FIG. 2Billustrates a flowchart of a process of performing a cell measurement operation according to an embodiment.

The terminal2b-05performs a connection establishment procedure with a first base station2b-10and then switches to a connected mode (2b-13). The first base station2b-10consults a second base station2b-12, thereby triggering dual connectivity (DC). The dual connectivity (DC) refers to technology in which a terminal receives a wireless communication service while being connected to a plurality of base stations. The first base station2b-10is a master node (MN), and configures, to the terminal2b-05, one or more serving cells of the second base station2b-12{i.e., a secondary node (SN)} (2b-14). If both the first base station2b-10and the second base station2b-12are NR base stations, the state may be referred to as “NR-DC”; if the first base station2b-10is an LTE base station and if the second base station2b-12is an NR base station, the state may be referred to as “EN-DC”; and if the first base station2b-10is an NR base station and if the second base station2b-12is an LTE base station, the state may be referred to as “NE-DC”.

The first base station2b-10transmits configuration information related to cell measurement to the terminal2b-05in a connected mode through a predetermined RRC message (2b-15). The configuration information related to cell measurement (measConfig IE) may be primarily including “measObject”, “reportConfig”, and “measId” indicating a combination of one “measObject” and one “reportConfig”. “measObject” contains information on the frequency and the cell to be measured, and “reportConfig” includes information to be applied for reporting the collected measurement information, periodic or event-based report time information, measurement information to report, and the like. “measObject”, “reportConfig”, and “measId” are configured in the form of a list, such as “measObjectToRemoveList”, “measObjectToAddModList”, “reportConfigToRemoveList”, “reportConfigToAddModList”, “measIdToRemoveList”, and “measIdToAddModList”, and are provided to the terminal2b-05. In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, “measGapSharingConfig”, and the like, is provided to the terminal2b-05. In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, “measGapSharingConfig”, and the like, is also provided to the terminal2b-05. The second base station2b-12may also transmit the information related to the cell measurement to the terminal2b-05in a connected mode through a predetermined RRC message (2b-17).

Since an NR base station may have a plurality of SCSs of the SS/PBCH to be transmitted, “MeasObjectNR” information may indicate the SCS value of the SS/PBCH block to be measured. In addition, since several SS/PBCH blocks may be located in the operating cell, the base station is able to inform the terminal of the frequency position of the SS/PBCH block that is to be measured by the terminal. Since an NR terminal has one or more configured BWPs, the base station is capable of configuring one or more BWPs to be measured and informing the terminal of the same. The terminal may measure the BWP, based on the information received from the base station. Alternatively, the NR terminal is capable of measuring the SS/PBCH block or the CSI-RS included in the activated BWP.

See Table 1 for the MeasObjectNR information element.

Upon receiving the information, the terminal2b-05applies the cell measurement information (2b-20).

In the disclosure, the terminal2b-05determines one serving cell for the s-measure operation (2b-30). If DC is not configured in the terminal2b-05, the terminal always selects the PCell. On the other hand, if DC is configured in the terminal2b-05, in an embodiment, the terminal selects the SpCell belonging to NR. More specifically, since the SpCell belonging to NR is the PSCell in EN-DC, and since the SpCell belonging to NR is the PCell in NE-DC, only one SpCell can belong to NR in EN-DC and NE-DC. Accordingly, the cell belonging to NR is selected. On the other hand, there are a PCell and a PSCell as the SpCells belonging to NR in NR-DC. According to an embodiment, the PCell is always selected from among the SpCells belonging to NR in NR-DC.

In another embodiment, the terminal in the NR-DC, EN-DC, or NE-DC state, if one NR SpCell is configured according to the number of SpCells belonging to the configured NR, selects an NR PSCell and an NR PCell in EN-DC and NE-DC, respectively, and if two or more NR SpCells are configured, the terminal always selects an NR PCell.

In another embodiment, it is possible to determine the serving cell for each operation frequency if DC is configured. In an embodiment, the terminal in the NR-DC, EN-DC, or NE-DC state, if one NR SpCell is configured according to the number of SpCells belonging to the configured NR, selects an NR PSCell and an NR PCell in EN-DC and NE-DC, respectively. If two or more NR SpCells are configured, and if there are NR SpCell1operating in FR1and NR SpCell2operating in FR2, the terminal selects both NR SpCell1and NR SpCell2as serving cells. More specifically, the terminal may determine the serving cell for “s-measure”, based on the RRC information for configuring DC.

In another embodiment of NR-DC, each of the MN and the SN provides a separate “s-measure” to be applied to the cell measurement operation, which is configured by the MN and the SN, to the terminal. Upon receiving the two “s-measures”, the terminal2b-05compares the RSRP of the PCell of the MN with “s-measure” applied to the cell measurement operation, which is configured by the MN, and compares the RSRP of the PSCell of the SN with “s-measure” applied to the measurement operation, which is configured by the SN. The MN may provide both “s-measure” applied to the cell measurement operation, which is configured by the MN, and “s-measure” applied to the cell measurement operation, which is configured by the SN, to the terminal2b-05, and the SN may provide “s-measure” applied to the cell measurement operation, which is configured by the SN. If both the MN and the SN provide the terminal2b-05with “s-measures” applied to the cell measurement operation, which are configured by the SN, one of the two values is selected and applied. In this case, “s-measure” having the highest value may be applied, or “s-measure” provided by a specific node may be applied.

“s-MeasureConfig” stores a predetermined SSB-RSRP threshold and a CSI-RSRP threshold. If “s-MeasureConfig” is not provided, if the RSRP value measured from the SSB of the selected serving cell is less than the SSB-RSRP threshold, or if the RSRP value measured from the CSI-RS of the selected serving cell is less than the SSB-RSRP threshold (2b-25), the terminal2b-05measures the frequency indicated by “measObject” (2b-30). The determination as to whether or not to perform measurement is made every predetermined period. If “rsType” contained in “reportConfig” indicates “csi-rs”, the terminal2b-05derives an RSRP or RSRQ value obtained by measuring the CSI-RS, which will be described below. If “rsType” contained in “reportConfig” indicates an SSB, the terminal derives an RSRP or RSRQ value obtained by measuring the SSB, which will be described below.

If “reportQuantityRS-Indexes” and “maxNrofRS-IndexesToReport” are contained in “reportConfig”, the terminal derives a measurement value indicated by “reportQuantityRS-Indexes” contained in “reportConfig” by performing 3-filtered beam measurement. “reportQuantityRS-Indexes” may have one of RSRP, RSRQ, and SINR (signal-to-interference plus noise ratio).

In addition, the terminal derives a measurement value of the cell level indicated by “reportQuantityCell” contained in “measObject”. “reportQuantityCell” may have one of RSRP, RSRQ, and SINR.

The terminal2b-05includes the measured result in a predetermined RRC message periodically or on an event basis, and reports the same to the base stations2b-10and2b-12(2b-35).

FIG. 2Cillustrates a flowchart of the operation of a terminal for performing a cell measurement operation according to an embodiment.

In step2c-05, a terminal connects with a first base station.

In step2c-10, the terminal in a connected state with the first base station further connects with a second base station, based on configuration information received from the first base station.

In step2c-15, the terminal receives measurement configuration including configuration information on “s-measure” from the first base station or the second base station.

In step2c-20, the terminal applies the configuration information, thereby determining whether or not it is necessary to measure neighboring frequencies and cells.

In step2c-25, if it is determined that the measurement is necessary, the terminal measures the SSB or CSI-RS indicated by the configuration information, thereby deriving a measurement result.

In step2c-30, the terminal reports the measurement result to the base station using a predetermined RRC message.

The specific operation of the terminal is not limited thereto, and may include the operation of the terminal described with reference toFIG. 2B.

FIG. 2Dillustrates a diagram of the configuration of a terminal according to an embodiment.

Referring toFIG. 2D, the terminal includes a radio frequency (RF) processor2d-10, a baseband processor2d-20, a storage unit2d-30, and a controller2d-40. The controller2d-40may further include a multi-connection processor2d-42.

The RF processor2d-10performs a function of transmitting and receiving a signal through a radio channel, such as band conversion and amplification of a signal. That is, the RF processor2d-10up-converts a baseband signal provided from the baseband processor2d-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor2d-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Although only one antenna is illustrated inFIG. 2D, the terminal may have a plurality of antennas. In addition, the RF processor2d-10may include a plurality of RF chains. Further, the RF processor2d-10may perform beamforming. To perform beamforming, the RF processor2d-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. In addition, the RF processor may perform MIMO, and may receive multiple layers when performing the MIMO operation.

The baseband processor2d-20performs a function of conversion between a baseband signal and a bit string according to the physical layer specification of the system. For example, in the case of data transmission, the baseband processor2d-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, when receiving data, the baseband processor2d-20demodulates and decodes a baseband signal provided from the RF processor2d-10to thus recover reception bit strings. For example, in the case where an orthogonal frequency division multiplexing (OFDM) scheme is applied, when transmitting data, the baseband processor2d-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through an inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processor2d-20divides the baseband signal provided from the RF processor2d-10into OFDM symbol units, restores the signals mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then restores reception bit strings through demodulation and decoding.

The baseband processor2d-20and the RF processor2d-10transmit and receive signals as described above. Accordingly, the baseband processor2d-20and the RF processor2d-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, or a “communication unit”. Further, at least one of the baseband processor2d-20and the RF processor2d-10may include a plurality of communication modules in order to support a plurality of different radio access techniques. In addition, at least one of the baseband processor2d-20and the RF processor2d-10may include different communication modules to process signals in different frequency bands. For example, the different radio access techniques may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), and the like. In addition, the different frequency bands may include super-high frequency (SHF) (e.g., 2.NRHz or NRHz) bands or millimeter wave (e.g., 60 GHz) bands.

The storage unit2d-30stores data such as fundamental programs, application programs, and configuration information for the operation of the terminal. In particular, the storage unit2d-30may store information related to a second access node that performs wireless communication using a second radio access technique. In addition, the storage unit2d-30provides the stored data at the request of the control unit2d-40.

The controller2d-40controls the overall operation of the terminal. For example, the controller2d-40transmits and receives signals through the baseband processor2d-20and the RF processor2d-10. In addition, the controller2d-40records and reads data in and from the storage unit2d-30. To this end, the controller2d-40may include at least one processor. For example, the controller2d-40may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling higher-layers such as application programs.

FIG. 2Eillustrates a diagram of the configuration of a base station according to an embodiment.

As shown inFIG. 2E, the base station includes an RF processor2e-10, a baseband processor2e-20, a backhaul communication unit2e-30, a storage unit2e-40, and a controller2e-50. The controller2e-50may further include a multi-connection processor2e-52.

The RF processor2e-10performs a function of transmitting and receiving signals, such as band conversion and amplification of a signal, through a radio channel. That is, the RF processor2e-10up-converts a baseband signal provided from the baseband processor2e-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor2e-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may have a plurality of antennas. In addition, the RF processor2e-10may include a plurality of RF chains. Further, the RF processor2e-10may perform beamforming. To perform beamforming, the RF processor2e-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. The RF processor may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processor2e-20performs a function of conversion between a baseband signal and a bit string according to a physical layer specification of a first radio access technique. For example, when transmitting data, the baseband processor2e-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, when receiving data, the baseband processor2e-20demodulates and decodes a baseband signal provided from the RF processor2e-10to thus recover reception bit strings. For example, in the case where an OFDM scheme is applied, when transmitting data, the baseband processor2e-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through the IFFT operation and CP insertion. In addition, when receiving data, the baseband processor2e-20divides the baseband signal provided from the RF processor2e-10into OFDM symbol units, restores the signals mapped to the subcarriers through the FFT operation, and then restores reception bit strings through demodulation and decoding. The baseband processor2e-20and the RF processor2e-10transmit and receive signals as described above. Accordingly, the baseband processor2e-20and the RF processor2e-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, a “communication unit”, or a “wireless communication unit”.

The backhaul communication unit2e-30provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit2e-30converts a bit string, transmitted from the base station to another node, such as a secondary base station, a core network, etc., into a physical signal, and converts physical signals received from other nodes into bit strings.

The storage unit2e-40stores data such as fundamental programs, application programs, and configuration information for the operation of the base station. In particular, the storage unit2e-40may store information about bearers allocated to a connected terminal, a measurement result reported from a connected terminal, and the like. In addition, the storage unit2e-40may store information that is a criterion for determining whether a multi-connection is provided to the terminal or is released. In addition, the storage unit2e-40provides the stored data in response to a request from the controller2e-50.

The controller2e-50controls the overall operation of the base station. For example, the controller2e-50transmits and receives signals through the baseband processor2e-20and the RF processor2e-10or the backhaul communication unit2e-30. In addition, the controller2e-50records and reads data in and from the storage unit2e-40. To this end, the controller2e-50may include at least one processor.

The description of the block diagram $00of electronic device #01for supporting legacy network communication and 5G network communication described with reference toFIG. 1Hmay also be applied to the second embodiment.

Third Embodiment

A third embodiment relates to a method and an apparatus for reporting a measurement result by a terminal supporting dual connectivity in a next-generation mobile communication system.

FIG. 3Aillustrates a diagram of the structure of an LTE system according to an embodiment.

Referring toFIG. 3, a radio access network of an LTE system may include evolved Node Bs) (hereinafter, referred to as “ENBs”, “Node Bs”, or “base stations”)3a-05,3a-10,3a-15, and3a-20, a mobility management entity (MME)3a-25, and a serving-gateway (S-GW)3a-30. User equipment (hereinafter, referred to as “UE” or a “terminal”)3a-35accesses an external network through the ENBs3a-05,3a-10,3a-15, and3a-20and the S-GW3a-30.

InFIG. 3, the ENBs3a-05,3a-10,3a-15, and3a-20may correspond to existing Node Bs of a universal mobile telecommunication system (UMTS). The ENBs3a-05,3a-10,3a-15, and3a-20may be connected to the UE3a-35via a radio channel, and may play a more complex role than the existing Node B. In the LTE system, all user traffic including real-time services, such as voice-over-IP (VoIP) through the Internet protocol, is served through a shared channel. Therefore, a device for collecting status information, such as buffer status, available transmission power status, and channel status of UEs, and performing scheduling is required. The ENBs3a-05,3a-10,3a-15, and3a-20serve as such a device.

One ENB typically controls multiple cells. For example, in order to realize a data rate of 100 Mbps, the LTE system uses, as radio access technology, orthogonal frequency division multiplexing (hereinafter, referred to as “OFDM”) in, for example, a 20 MHz bandwidth. Further, an adaptive modulation and coding (hereinafter, referred to as “AMC”) scheme is applied to determine a modulation scheme and a channel coding rate in accordance with the channel status of a terminal. The S-GW3a-30is a device for providing data bearers, and generates or removes data bearers under the control of the MME3a-25. The MME3a-25is a device that performs various control functions, as well as a mobility management function for a terminal, and may be connected to a plurality of base stations.

For the configuration of the SS block and the method of transmitting the SS block, reference is to be made to the configuration described with reference toFIGS. 1AH, 1AI, 1AJ, and 1AKof the first embodiment. For the frame structure, reference is to be made to the configuration described with reference toFIG. 1ALof the first embodiment. For the initial access procedure, reference is to be made to the configuration described with reference toFIG. 1AMof the first embodiment.

FIG. 3Billustrates a diagram of a radio protocol structure in an LTE system according to an embodiment.

Referring toFIG. 3B, the radio protocol of an LTE system may include a packet data convergence protocol (PDCP)3b-05or3b-40, a radio link control (RLC)3b-10or3b-35, and a medium access control (MAC)3b-15or3b-30in a terminal and an ENB, respectively. For the primary functions of the PDCP, the RLC, and the MAC, reference is to be made toFIG. 1AFin the first embodiment.

FIG. 3Cillustrates a diagram of the structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 3C, a radio access network of a next-generation mobile communication system (hereinafter, referred to as “NR” or “5G”) may include a new radio node B (hereinafter, referred to as an “NR gNB” or an “NR base station”)3c-10and a new radio core network (hereinafter, referred to as an “NR CN”)3c-05. New radio user equipment (hereinafter, referred to as “NR UE” or a “terminal”)3c-15accesses an external network through the NR gNB3c-10and the NR CN3c-05.

InFIG. 3C, the NR gNB3c-10corresponds to an evolved Node B (eNB) in an existing LTE system. The NR gNB3c-10is connected to the NR UE3c-15through a radio channel, and may provide services superior to those of the existing node B. In the next-generation mobile communication system, all user traffic is served through a shared channel. Therefore, a device for collecting status information, such as buffer status, available transmission power status, and channel status of UEs, and performing scheduling is required. The NR NB3c-10serves as such a device. One NR gNB3c-10may control multiple cells. In order to realize super-high data rates compared to the existing LTE system, the next-generation mobile communication system may have a bandwidth equal to or greater than the maximum bandwidth of the existing system. In addition, the next-generation mobile communication system may use, as radio access technology, orthogonal frequency division multiplexing (OFDM), and may further employ a beamforming technique in addition thereto. In addition, an adaptive modulation and coding (hereinafter, referred to as “AMC”) scheme may be applied to determine a modulation scheme and a channel coding rate in accordance with the channel status of a terminal.

The NR CN3c-05performs functions such as mobility support, bearer configuration, and QoS configuration. The NR CN3c-05is a device that performs various control functions, as well as a mobility management function for a terminal, and may be connected to a plurality of base stations. In addition, the next-generation mobile communication system may interwork with an existing LTE system, and the NR CN3c-05may be connected to the MME3c-25through a network interface. The MME3c-25may be connected to the eNB3c-30, which is an existing base station.

For the definition and system configuration of the NR-DC, reference is to be made to the description made with reference toFIGS. 1AB and 1ACin the first embodiment. For the configuration of a BWP, reference is to be made to the description made with reference toFIGS. 1AE and 1ADin the first embodiment.

FIG. 3Dillustrates a diagram of a radio protocol structure of a next-generation mobile communication system according to an embodiment.

Referring toFIG. 3D, the radio protocol of the next-generation mobile communication system includes NR service data adaptation protocol (SDAP)3d-01or3d-45, NR PDCP3d-05or3d-40, NR RLC3d-10or3d-35, NR MAC3d-15or3d-30, and NR PHY3d-20or3d-25in a terminal and an NR base station, respectively. For the primary functions of the NR PDCP, the NR RLC, and the NR MAC, reference is to be made toFIG. 1AGin the first embodiment.

FIG. 3Eillustrates a diagram of a procedure in which a terminal having established dual connectivity (hereinafter, referred to as “DC”) reports a measurement result to a base station, based on measurement configuration according to an embodiment.

Referring toFIG. 3E, a terminal3e-01may establish an RRC connection with a base station3e-02to thus switch to an RRC-connected mode (3e-05). If there is no transmission or reception of data for a predetermined reason or for a predetermined time, the base station3e-02may transmit an RRC connection release message (“RRCRelease”), excluding suspend configuration information (“suspendConfig”), to the terminal3e-01(3e-10). Upon receiving the RRC connection release message, the terminal3e-01may switch from the RRC-connected mode to an RRC-idle mode (3e-11).

The terminal3e-01in the RRC-idle mode may discover an appropriate cell through a cell selection procedure and/or a cell reselection procedure to thus camp thereon, thereby receiving system information (3e-15). The terminal3e-01may perform random access to the base station3e-02in order to establish an RRC connection therewith. When the random access is triggered (3e-16), the terminal3e-01may select a physical random access channel (PRACH) occasion, thereby transmitting a random access preamble to the base station3e-02(3e-20). Upon receiving the random access preamble, the base station3e-02may transmit a random access response (hereinafter, referred to as “RAR”) message to the terminal3e-01(3e-25). The terminal3e-01in the RRC-idle mode may establish reverse-link transmission synchronization with the base station3e-02through steps3e-20and3e-25. Meanwhile, in the embodiment, the same reference numeral is used for the base station in step3e-10and the base stations in step3e-15and steps subsequent thereto for the convenience of description, but the base stations prior to step3e-15and the base stations in the step3e-15and steps subsequent thereto may be different from each other depending on the mobility of the terminal and the results of selection and reselection of the cell.

The terminal3e-01having established the reverse-link transmission synchronization may perform an RRC connection establishment procedure with the base station3e-02. First, the terminal3e-01may transmit an RRC connection setup request message (“RRCSetupRequest”) to the base station3e-02(3e-30). The message may include, for example, an identifier of the terminal3e-01(“ue-Identity”), a cause for establishing an RRC connection (“establishmentCause”), and the like. If the RRC connection setup request message is received, the base station3e-02may transmit an RRC connection setup message (“RRCSetup”) to the terminal3e-01(3e-35). The RRC connection setup message may include radio bearer configuration information (“radioBearerConfig”) and master cell group configuration information (“masterCellGroup”). If the RRC connection setup message is received, the terminal3e-01may apply the radio bearer configuration information and the master cell group configuration information, and may then switch to an RRC-connected mode (3e-36). The RRC connection establishment may involve a connection of signaling radio bearer1 (SRB1). Therefore, an RRC message, which is a control message between the terminal3e-01and the base station3e-02, an RRC message including a NAS message, or an initial NAS message may be transmitted and received between the terminal3e-01and the base station3e-02through SRB1. The terminal3e-01that has switched to the RRC-connected mode may transmit an RRC connection setup completion message (“RRCSetupComplete”) to the base station3e-02through SRB1 (3e-40). The RRC connection setup completion message may include a service request message for the terminal3e-01to make a request to the AMF or MME for bearer configuration for a predetermined service.

If the RRC connection establishment procedure is successfully performed, the base station3e-02may transmit a security mode command message (“SecurityModeCommand”) to the terminal3e-01in order to activate AS security with respect to the terminal3e-01in the RRC-connected mode (3e-45). When the security mode command message is received and the AS security is activated, the terminal3e-01may transmit a security mode completion message (“SecurityModeComplete”) to the base station (3e-50).

The base station3e-02may perform an RRC connection reconfiguration procedure with the terminal3e-01at the time of transmitting the security mode command message, after transmitting the security mode command message, or after receiving the security mode completion message. The base station3e-02may transmit an RRC connection reconfiguration message (“RRCReconfiguration”) to the terminal3e-01(3e-55). The RRC connection reconfiguration message may include at least one piece of radio bearer configuration information (“radioBearerConfig”), master cell group information (“masterCellGroup”), or measurement configuration (“measConfig”). Upon receiving the RRC connection reconfiguration message, the terminal3e-01may apply the above information, and may then transmit an RRC connection reconfiguration completion message (“RRCReconfigurationComplete”) to the base station3e-02(3e-60).

If the RRC connection reconfiguration message includes measurement configuration (“measConfig”) in step3e-55, the terminal3e-01in the RRC-connected mode may perform measurement by applying the information, and, if measurement reporting is triggered (3e-61), may transmit a measurement report message (“MeasurementReport”) to the base station3e-02(3e-65).

The base station3e-02having successfully received the measurement report message may discuss with another base station3e-03, and may then perform an RRC connection reconfiguration procedure in order to establish dual connectivity (DC) with respect to the terminal3e-01in the RRC-connected mode. DC according to an embodiment refers to a technique in which a terminal receives a wireless communication service through a master cell group (hereinafter, referred to as an “MCG”) and a secondary cell group (hereinafter, referred to as an “SCG”). According to an embodiment, the first base station3e-02may denote an MCG, and the second base station3e-03may denote an SCG. The MCG may include a primary cell (hereinafter, referred to as a “PCell”), or may include a PCell and one or more secondary cells (hereinafter, referred to as “SCells”). The SCG may include a primary SCG cell (hereinafter, referred to as a “PSCell”), or may include a PSCell and one or more SCells. If DC is configured for the terminal3e-01, a special cell may be a PCell of the MCG or a PSCell of the SCG.

The second base station3e-03may produce a message including at least one piece of NR secondary cell group information (“nr-SCG”) or radio bearer configuration information 2 (“radioBearerConfig2”), and may transmit the same to the first base station3e-02in order to configure DC for the terminal3e-01, and the first base station3e-02receiving the message may transmit an RRC connection reconfiguration message including the information to the terminal3e-01(3e-70). The secondary cell group information included in the RRC connection reconfiguration message may include at least one piece of secondary cell group configuration information (“secondaryCellGroup”) and measurement configuration (“measConfig”). Alternatively, in the case where SRB3 is configured in the terminal3e-01, the second base station3e-03may directly transmit, to the terminal, an RRC connection reconfiguration message including at least one piece of NR secondary cell group information (“nr-SCG”) and radio bearer configuration information 2 (“radioBearerConfig2”) (3e-75). The terminal3e-02having successfully received the RRC connection reconfiguration message from the first base station3e-02may apply the configuration information, and may then transmit an RRC connection reconfiguration completion message to the first base station3e-02(3e-71). The terminal3e-01may transmit/receive data to/from the first base station3e-02and the second base station3e-03. Alternatively, the terminal3e-01having successfully received the RRC connection reconfiguration message from the second base station3e-03may apply the configuration information, and may then transmit an RRC connection reconfiguration completion message to the second base station3e-03(3e-76).

If the RRC connection reconfiguration message includes measurement configuration (“measConfig”) in step3e-70or3e-75, the terminal3e-01may apply the received measurement configuration and then store the same. The measurement configuration may include at least one of “measObjectToRemoveList”, “measObjectToAddModList”, “reportConfigToRemoveList”, “reportConfigToAddModList”, “measIdToRemoveList”, and “measIdToAddModList”,measObjectToRemoveList: This may denote a list including one or more “MeasObjectIds” to be removed (an identifier used to identify a measurement object configuration).measObjectToAddModList: This may denote a list including one or more pieces of measurement object information to be added or modified. Each piece of measurement object information may include “measObjectId” and “measObject” (a measurement object). One of “measObjectNR” for NR and “measObjectEUTRA” for LTE may be selected and contained in “measObject”.reportConfigToRemoveList: This may denote a list including one or more “ReportConfigIDs” to be removed (identifiers used to identify measurement reporting configurations).reportConfigToAddModList: This may denote a list including one or more pieces of reporting configuration information to be added or modified. Each piece of reporting configuration information may include “reportConfigId” and “reportConfig”. One of “reportConfigNR” for NR and “reportConfigInterRAT” for another radio access technology may be selected and contained in “reportConfig”.“reportConfigNR” may include information on criteria for triggering an NR measurement reporting event. For example, the first base station3e-02or the second base station3e-03may include information on criteria for triggering event A3 or event A5 in “reportConfigNR”.

Event A3: the case in which the measurement result/signal of a neighboring cell becomes greater than the measurement result/signal of an SpCell by an offset

Event A5: the case in which the measurement result/signal of an SpCell becomes less than a specific value (threshold1) and in which the measurement result/signal of a neighboring cell/Scell becomes greater than a specific value (threshold 2)measIdToRemoveList: This may denote a list including one or more “MeasIds” to be removed (an identifier used to identify a measurement configuration and connecting “MeasObjectId” and “ReportConfigId”).measIdToAddModList: This may denote a list including one or more pieces of measurement identification information (measurement identities) to be added or modified. Each piece of measurement identification information may include “measId”, “measObjectId”, and “reportConfigID”.

Since an NR base station may have a plurality of SCSs of the SS/PBCH to be transmitted, “MeasObjectNR” information may indicate the SCS value of the SS/PBCH block to be measured. In addition, since several SS/PBCH blocks may be located in the operating cell, the base station is able to inform the terminal of the frequency position of the SS/PBCH block that is to be measured by the terminal. Since an NR terminal has one or more configured BWPs, the base station is capable of configuring one or more BWPs to be measured and informing the terminal of the same. The terminal may measure the BWP, based on the information received from the base station. Alternatively, the NR terminal is capable of measuring the SS/PBCH block or the CSI-RS included in the activated BWP.

See Table 1 for the MeasObjectNR information element.

In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, and “measGapSharingConfig”, may be provided as the measurement configuration to the terminal. If the first base station3e-02or the second base station3e-03according to the embodiment configures at least one of event A3 or event A5 to the terminal3e-01, “reportConfigNR” includes an indicator indicating whether the SpCell is the PCell of the MCG or the PSCell of the SCG. The indicator according to the embodiment may indicate the same by one of the following methods.

Method 1: usePSCell BOOLEAN OPTIONAL NEED MusePSCell: This may denote a field indicating whether to apply the PSCell of the SCG or the PCell of the MCG to at least one of event A3 or event A5.BOOLEAN: “usePSCell” may be configured as 1 bit, and if it is set to 0 (or “FALSE”), the terminal3e-01applies the PCell of the MCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions. If it is set to 1 (or “TRUE”), the terminal3e-01may apply the PSCell of the SCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions.OPTIONAL NEED M: “reportConfigNR” mapped to “reportConfigId” may selectively include the field “usePSCell”. If the field “usePSCell” is set to 0, the terminal3e-01may store the same, and may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Therefore, even though “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. If the field “usePSCell” is set to 1, the terminal3e-01may store the same, and may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Therefore, even though “usePSCell” is not signaled later, the terminal may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions.

Method 2: usePSCell ENUMERATED {true} OPTIONAL NEED RusePSCell: This may denote a field indicating whether to apply the PSCell of the SCG or the PCell of the MCG to at least one of event A3 or event A5.ENUMERATED {true}: “usePSCell” may be configured as 1 bit, and if it is not set to “TRUE”, the terminal3e-01applies the PCell of the MCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions. If it is set to “TRUE”, the terminal3e-01may apply the PSCell of the SCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions.OPTIONAL NEED R: “reportConfigNR” mapped to “reportConfigId” may selectively include the field “usePSCell”. If the field “usePSCell” is not set to “TRUE”, the terminal3e-01may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Thereafter, the corresponding field may be deleted. Therefore, in the case where “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. If the field “usePSCell” is set to 1, the terminal3e-01may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Thereafter, the corresponding field may be deleted. Therefore, in the case where “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG, which is configured by default, to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions.

In step3e-80, the terminal3e-01that has configured DC may perform measurement, and may determine whether measurement reporting is triggered. If the base station3e-02or3e-03configures at least one of event A3 or event A5 for the terminal3e-01through “reportConfig” in step3e-70or step3e-75, the terminal3e-01may determine whether an entering condition or a leaving condition is satisfied for at least one of event A3 or event A5 during “timeToTrigger” through the following equations.

If “usePSCell” is set to “TRUE” in “reportConfig”, the above equations may be determined by applying the values Mp, Ofp, and Ocp of the PScell. Otherwise, the equations may be determined by applying the values Mp, Ofp, and Ocp of the PCell.

Definition of the parameters used in Equations 1 and 2 may be determined with reference to the 3GPP standards document “38.331: Radio Resource Control (RRC)”, and the parameters may be included in “measConfig”.

Event A5 Entering Conditions

Event A5 Leaving Conditions

If “usePSCell” is set to “TRUE” in “reportConfig”, the equation may be determined by applying the value Mp of the PScell. Otherwise, the equation may be determined by applying the value Mp of the PCell.

Definition of the parameters used in Equations 3 and 4 may be determined with reference to the 3GPP standards document “38.331: Radio Resource Control (RRC)”, and the parameters may be included in “measConfig”.

If event A3 or event A5 is triggered by SCG measurement configuration in step3e-80(for example, if “usePSCell” is set to “TRUE”), a measurement report message (“MeasurementReport”) may be transmitted to the first base station3e-02or the second base station3e-03depending on whether or not SRB3 is configured in the terminal3e-01. The terminal3e-01configured with SRB3 may transmit a measurement report message (“MeasurementReport”) to the second base station3e-03(3e-85). The terminal3e-01, which is not configured with SRB3, may transmit a UE information transmission message for MRDC (“ULInformationTransferMRDC”) containing a measurement report message to the first base station3e-02, or may transmit a measurement report message to the first base station3e-02(3e-90).

FIG. 3Fillustrates a diagram of a procedure in which a terminal configuring dual connectivity (hereinafter, referred to as “DC”) reports a measurement result to a base station, based on a measurement configuration according to an embodiment.

Referring toFIG. 3F, a terminal3f-01may establish an RRC connection with a base station3f-02to thus switch to an RRC-connected mode (3f-05). If there is no transmission or reception of data for a predetermined reason or for a predetermined time, the base station3f-02may transmit an RRC connection release message (“RRCRelease”) including suspend configuration information (“suspendConfig”) to the terminal3f-01(3f-10). Upon receiving the RRC connection release message, the terminal3f-01may switch from the RRC-connected mode to an RRC inactive mode (3f-11). Meanwhile, in the embodiment, the same reference numeral is used for the base station in step3f-10and the base stations in step3f-15and steps subsequent thereto for the convenience of description, but the base stations prior to step3f-15and the base stations in the step3f-15and steps subsequent thereto may be different from each other depending on the mobility of the terminal and the results of selection and reselection of the cell.

The terminal3f-01in the RRC inactive mode may discover an appropriate cell through a cell selection procedure and/or a cell reselection procedure to thus camp thereon, thereby receiving system information (3f-15). The terminal3f-01may perform random access to the base station3f-02in order to establish an RRC connection therewith. When the random access is triggered (3f-16), the terminal3f-01may select a PRACH occasion, thereby transmitting a random access preamble to the base station3f-02(3f-20). Upon receiving the random access preamble, the base station3f-02may transmit a random access response (hereinafter, referred to as “RAR”) message to the terminal3f-01(3f-25). The terminal3f-01in the RRC inactive mode may establish reverse-link transmission synchronization with the base station3f-02through steps3f-20and3f-25.

The terminal3f-01having established the reverse-link transmission synchronization may perform an RRC connection resume procedure with the base station3f-02. First, the terminal3f-01may transmit an RRC connection resume request message (“RRCResumeRequest”) to the base station3f-02(3f-30). The RRC connection resume request message may include, for example, an identifier of the terminal3f-01(“resumeIdentity”), a cause for resuming an RRC connection (“resumeCause”), and the like. If the RRC connection resume request message is received, the base station3f-02may transmit an RRC connection resume message (“RRCResume”) to the terminal3f-01(3f-35). The RRC connection resume message may include at least one piece of radio bearer configuration information (“radioBearerConfig”), master cell group configuration information (“masterCellGroup”), and measurement configuration (“measConfig”). If the RRC connection resume message is received, the terminal3f-01may apply the received information, and may then switch to an RRC-connected mode (3f-36). The RRC connection resume may involve a connection of signaling radio bearer1 (SRB1). Therefore, an RRC message, which is a control message between the terminal3f-01and the base station3f-02, an RRC message including a NAS message, or an initial NAS message may be transmitted and received between the terminal3f-01and the base station3f-02through SRB1. The terminal3f-01that has switched to the RRC-connected mode may transmit an RRC connection resume completion message (“RRCResumeComplete”) to the base station3f-02through SRB1 (3f-40). If the RRC connection resume procedure is successfully performed, the base station3f-02may transmit a security mode command message (“SecurityModeCommand”) to the terminal3f-01in order to activate AS security with respect to the terminal3f-01in the RRC-connected mode (3f-45). When the security mode command message is received and the AS security is activated, the terminal3f-01may transmit a security mode completion message (“SecurityModeComplete”) to the base station (3f-50).

The base station3f-02may perform an RRC connection reconfiguration procedure with the terminal3f-01at the time of transmitting the security mode command message, after transmitting the security mode command message, or after receiving the security mode completion message. The base station3f-02may transmit an RRC connection reconfiguration message (“RRCReconfiguration”) to the terminal3f-01(3f-55). The RRC connection reconfiguration message may include at least one piece of radio bearer configuration information (“radioBearerConfig”), master cell group information (“masterCellGroup”), or measurement configuration (“measConfig”). Upon receiving the RRC connection reconfiguration message, the terminal3f-01may apply the above information, and may then transmit an RRC connection reconfiguration completion message (“RRCReconfigurationComplete”) to the base station3f-02(3f-60).

If the RRC connection reconfiguration message includes measurement configuration (“measConfig”) in step3f-55, the terminal3f-01in the RRC-connected mode may perform measurement by applying the information, and, if measurement reporting is triggered (3f-61), may transmit a measurement report message (“MeasurementReport”) to the base station3f-02(3f-65).

The base station3f-02having successfully received the measurement report message may discuss with another base station3f-03, and may then perform an RRC connection reconfiguration procedure in order to establish dual connectivity (DC) with respect to the terminal3f-01in the RRC-connected mode. DC according to an embodiment refers to a technique in which a terminal receives a wireless communication service through a master cell group (hereinafter, referred to as an “MCG”) and a secondary cell group (hereinafter, referred to as an “SCG”). According to an embodiment, the first base station3f-02may denote an MCG, and the second base station3f-03may denote an SCG. The MCG may include a primary cell (hereinafter, referred to as a “PCell”), or may include a PCell and one or more secondary cells (hereinafter, referred to as “SCells”). The SCG may include a primary SCG cell (hereinafter, referred to as a “PSCell”), or may include a PSCell and one or more SCells. If DC is configured for the terminal3f-01, a special cell may be a PCell of the MCG or a PSCell of the SCG.

The second base station3f-03may produce a message including at least one piece of NR secondary cell group information (“nr-SCG”) or radio bearer configuration information 2 (“radioBearerConfig2”) and transmit the same to the first base station3f-02in order to configure DC for the terminal3f-01, and the first base station3f-02receiving the message may transmit an RRC connection reconfiguration message including the information to the terminal3f-01(3f-70). The secondary cell group information included in the RRC connection reconfiguration message may include at least one piece of secondary cell group configuration information (“secondaryCellGroup”) and measurement configuration (“measConfig”). Alternatively, in the case where SRB3 is configured in the terminal3f-01, the second base station3f-03may directly transmit, to the terminal, an RRC connection reconfiguration message including at least one piece of NR secondary cell group information (“nr-SCG”) and radio bearer configuration information 2 (“radioBearerConfig2”) (3f-75). The terminal3f-02having successfully received the RRC connection reconfiguration message from the first base station3f-02may apply the configuration information, and may then transmit an RRC connection reconfiguration completion message to the first base station3f-02(3f-71). The terminal3f-01may transmit/receive data to/from the first base station3f-02and the second base station3f-03. Alternatively, the terminal3f-01having successfully received the RRC connection reconfiguration message from the second base station3f-03may apply the configuration information, and may then transmit an RRC connection reconfiguration completion message to the second base station3f-03(3f-76).

If the RRC connection reconfiguration message includes measurement configuration (“measConfig”) in step3f-70or3f-75, the terminal3f-01may apply the received measurement configuration and then store the same. The measurement configuration may include at least one of “measObjectToRemoveList”, “measObjectToAddModList”, “reportConfigToRemoveList”, “reportConfigToAddModList”, “measIdToRemoveList”, and “measIdToAddModList”,measObjectToRemoveList: This may denote a list including one or more “MeasObjectIds” to be removed (an identifier used to identify a measurement object configuration).measObjectToAddModList: This may denote a list including one or more pieces of measurement object information to be added or modified. Each piece of measurement object information may include “measObjectId” and “measObject” (a measurement object). One of “measObjectNR” for NR and “measObjectEUTRA” for LTE may be selected and contained in “measObject”.reportConfigToRemoveList: This may denote a list including one or more “ReportConfigIDs” to be removed (identifiers used to identify measurement reporting configurations).reportConfigToAddModList: This may denote a list including one or more pieces of reporting configuration information to be added or modified. Each piece of reporting configuration information may include “reportConfigId” and “reportConfig”. One of “reportConfigNR” for NR and “reportConfigInterRAT” for another radio access technology may be selected and contained in “reportConfig”.“reportConfigNR” may include information on criteria for triggering an NR measurement reporting event. For example, the first base station3f-02or the second base station3f-03may include information on criteria for triggering event A3 or event A5 in “reportConfigNR”.

Event A3: the case in which the measurement result/signal of a neighboring cell becomes greater than the measurement result/signal of an SpCell by an offset

Event A5: the case in which the measurement result/signal of an SpCell becomes less than a specific value (threshold1) and in which the measurement result/signal of a neighboring cell/Scell becomes greater than a specific value (threshold 2)measIdToRemoveList: This may denote a list including one or more “MeasIds” to be removed (an identifier used to identify a measurement configuration and connecting “MeasObjectId” and “ReportConfigId”).measIdToAddModList: This may denote a list including one or more pieces of measurement identification information (measurement identities) to be added or modified. Each piece of measurement identification information may include “measId”, “measObjectId”, and “reportConfigID”.

Since an NR base station may have a plurality of SCSs of the SS/PBCH to be transmitted, “MeasObjectNR” information may indicate the SCS value of the SS/PBCH block to be measured. Since an NR terminal has one or more configured BWPs, the base station is capable of configuring one or more BWPs to be measured and informing the terminal of the same. The terminal may measure the BWP, based on the information received from the base station. Alternatively, the NR terminal is capable of measuring the SS/PBCH block or the CSI-RS included in the activated BWP.

See Table 1 for the MeasObjectNR information element.

In addition, configuration information related to cell measurement, such as “s-MeasureConfig”, “quantityConfig”, “measGapConfig”, and “measGapSharingConfig”, may be provided as the measurement configured to the terminal. If the first base station3f-02or the second base station3f-03according to the embodiment configures at least one of event A3 or event A5 for the terminal3f-01, “reportConfigNR” includes an indicator indicating whether the SpCell is the PCell of the MCG or the PSCell of the SCG. The indicator according to the embodiment may indicate the same by one of the following methods.

Method 1: usePSCell BOOLEAN OPTIONAL NEED MusePSCell: This may denote a field indicating whether to apply the PSCell of the SCG or the PCell of the MCG to at least one of event A3 or event A5.BOOLEAN: “usePSCell” may be configured as 1 bit, and if it is set to 0 (or “FALSE”), the terminal3f-01applies the PCell of the MCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions. If it is set to 1 (or “TRUE”), the terminal3f-01may apply the PSCell of the SCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions.OPTIONAL NEED M: “reportConfigNR” mapped to “reportConfigId” may selectively include the field “usePSCell”. If the field “usePSCell” is set to 0, the terminal3f-01may store the same, and may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Therefore, even though “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. If the field “usePSCell” is set to 1, the terminal3f-01may store the same, and may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Therefore, even though “usePSCell” is not signaled later, the terminal may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions.

Method 2: usePSCell ENUMERATED {true} OPTIONAL NEED RusePSCell: This may denote a field indicating whether to apply the PSCell of the SCG or the PCell of the MCG to at least one of event A3 or event A5.ENUMERATED {true}: “usePSCell” may be configured as 1 bit, and if it is not set to “TRUE”, the terminal3f-01applies the PCell of the MCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions. If it is set to “TRUE”, the terminal3f-01may apply the PSCell of the SCG to at least one of event A3 or event A5 configured in “reportConfigNR” mapped to “reportConfigId”, thereby determining measurement reporting triggering conditions.OPTIONAL NEED R: “reportConfigNR” mapped to “reportConfigId” may selectively include the field “usePSCell”. If the field “usePSCell” is not set to “TRUE”, the terminal3f-01may apply the PCell of the MCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Thereafter, the corresponding field may be deleted. Therefore, in the case where “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG, which is configured by default, to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. If the field “usePSCell” is set to 1, the terminal3f-01may apply the PSCell of the SCG to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions. Thereafter, the corresponding field may be deleted. Therefore, in the case where “usePSCell” is not signaled later, the terminal may apply the PCell of the MCG, which is configured by default, to at least one of event A3 or event A5, thereby determining measurement reporting triggering conditions.

In step3f-80, the terminal3f-01that has configured DC may perform measurement, and may determine whether measurement reporting is triggered. If the base station3f-02or3f-03configures at least one of event A3 or event A5 for the terminal3f-01through “reportConfig” in step3f-70or step3f-75, the terminal may determine whether an entering condition or a leaving condition is satisfied for at least one of event A3 or event A5 during “timeToTrigger” through the following equations.

If “usePSCell” is set to “TRUE” in “reportConfig”, the above equations may be determined by applying the values Mp, Ofp, and Ocp of the PScell. Otherwise, the equations may be determined by applying the values Mp, Ofp, and Ocp of the PCell.

Definition of the parameters used in Equations 1 and 2 may be determined with reference to the 3GPP standards document “38.331: Radio Resource Control (RRC)”, and the parameters may be included in “measConfig”.

Event A5 Entering Conditions

Event A5 Leaving Conditions

If “usePSCell” is set to “TRUE” in “reportConfig”, the equations may be determined by applying the value Mp of the PScell. Otherwise, the equations may be determined by applying the value Mp of the PCell.

Definition of the parameters used in Equations 3 and 4 may be determined with reference to the 3GPP standards document “38.331: Radio Resource Control (RRC)”, and the parameters may be included in “measConfig”.

If event A3 or event A5 is triggered by SCG measurement configuration in step3f-80(for example, if “usePSCell” is set to “TRUE”), a measurement report message (“MeasurementReport”) may be transmitted to the first base station3f-02or the second base station3f-03depending on whether or not SRB3 is configured in the terminal3f-01. The terminal3f-01configured with SRB3 may transmit a measurement report message (“MeasurementReport”) to the second base station3f-03(3f-85). The terminal3f-01, which is not configured with SRB3, may transmit a UE information transmission message for MRDC (“ULInformationTransferMRDC”) containing a measurement report message to the first base station3f-02, or may transmit a measurement report message to the first base station3f-02(3f-90).

FIG. 3Gillustrates a flowchart of an operation in which a terminal configuring dual connectivity (hereinafter, referred to as “DC”) reports a measurement result to a base station when measurement reporting is triggered according to an embodiment.

In step3g-01, the terminal may establish an RRC connection with the first NR base station to thus switch to an RRC-connected mode.

In step3g-05, if an RRC connection reconfiguration message received from the first base station or the second base station includes configuration information on an NR-DC operation (“nr-SCG”), the terminal may store the same, and may perform the NR-DC operation.

In step3g-10, the terminal may perform measurement.

In step3g-15, the measurement configuration (“measConfig”) received by the terminal may indicate “usePSCell”, and event A3 or event A5 may occur by the SCG configuration, thereby triggering measurement reporting.

In step3g-20, in the case where SRB3 is configured in the terminal, a measurement result message (“MeasurementReport”) including a measurement result may be transmitted to the second base station. Alternatively, in the case where SRB3 is not configured in the terminal in step3g-20, a measurement result message including a measurement result may be transmitted to the first base station. Alternatively, in the case where SRB3 is not configured in the terminal in steps3g-20, a UE information transmission message for MRDC (“ULInformationTransferMRDC”) containing a measurement report message including a measurement result may be transmitted to the first base station.

In step3g-25, if an RRC connection reconfiguration message received from the first base station or the second base station includes configuration information on an NR-DC operation (“nr-SCG”), the terminal may store the same, and may perform the NR-DC operation.

In step3g-30, the terminal may perform measurement.

In step3g-35, if the measurement configuration (“measConfig”) received by the terminal does not indicate “usePSCell”, and if the first base station or the second base station configures “reportConfigNR” by method 1 in the embodiment described above, when event A3 or event A5 occurs by applying the PSCell, measurement reporting may be triggered.

In step3g-40, if SRB3 is configured in the terminal, a measurement result message (“MeasurementReport”) including a measurement result may be transmitted to the second base station. Alternatively, if SRB3 is not configured in the terminal in step3g-40, a measurement result message including a measurement result may be transmitted to the first base station. Alternatively, if SRB3 is not configured in the terminal in steps3g-40, a UE information transmission message for MRDC (“ULInformationTransferMRDC”) containing a measurement report message including a measurement result may be transmitted to the first base station.

In step3g-45, if the measurement configuration (“measConfig”) received by the terminal does not indicate “usePSCell”, and if the first base station or the second base station configures “reportConfigNR” by method 2 in the embodiment described above, when event A3 or event A5 occurs by applying the PCell, measurement reporting may be triggered.

In step3g-50, the terminal may transmit a measurement result message including a measurement result to the first base station.

FIG. 3Hillustrates a block diagram of the internal configuration of a terminal according to an embodiment.

Referring toFIG. 3H, the terminal includes a radio frequency (RF) processor3h-10, a baseband processor3h-20, a storage unit3h-30, and a controller3h-40. The controller3h-40may further include a multi-connection processor3h-42.

The RF processor3h-10performs a function of transmitting and receiving a signal through a radio channel, such as band conversion and amplification of a signal. That is, the RF processor3h-10up-converts a baseband signal provided from the baseband processor3h-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor3h-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Although only one antenna is illustrated inFIG. 3h, the terminal may have a plurality of antennas. In addition, the RF processor3h-10may include a plurality of RF chains. Further, the RF processor3h-10may perform beamforming. To perform beamforming, the RF processor3h-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. In addition, the RF processor may perform MIMO, and may receive multiple layers when performing the MIMO operation.

The baseband processor3h-20performs a function of conversion between a baseband signal and a bit string according to the physical layer specification of the system. For example, in the case of data transmission, the baseband processor3h-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, upon receiving data, the baseband processor3h-20demodulates and decodes a baseband signal provided from the RF processor3h-10to thus recover reception bit strings. For example, in the case where an orthogonal frequency division multiplexing (OFDM) scheme is applied, when transmitting data, the baseband processor3h-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through an inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processor3h-20divides the baseband signal provided from the RF processor3h-10into OFDM symbol units, restores the signals mapped to the subcarriers through a fast Fourier transform (FFT) operation, and then restores reception bit strings through demodulation and decoding.

The baseband processor3h-20and the RF processor3h-10transmit and receive signals as described above. Accordingly, the baseband processor3h-20and the RF processor3h-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, or a “communication unit”. Further, at least one of the baseband processor3h-20and the RF processor3h-10may include a plurality of communication modules in order to support a plurality of different radio access techniques. In addition, at least one of the baseband processor3h-20and the RF processor3h-10may include different communication modules to process signals in different frequency bands. For example, the different radio access techniques may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), and the like. In addition, the different frequency bands may include super-high frequency (SHF) (e.g., 2.NRHz or NRHz) bands or millimeter wave (e.g., 60 GHz) bands.

The storage unit3h-30stores data such as fundamental programs, application programs, and configuration information for the operation of the terminal. In particular, the storage unit3h-30may store information related to a second access node that performs wireless communication using a second radio access technique. In addition, the storage unit3h-30provides the stored data at the request of the control unit3h-40.

The controller3h-40controls the overall operation of the terminal. For example, the controller3h-40transmits and receives signals through the baseband processor3h-20and the RF processor3h-10. In addition, the controller3h-40records and reads data in and from the storage unit3h-30. To this end, the controller3h-40may include at least one processor. For example, the controller3h-40may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling higher-layers such as application programs.

FIG. 3Iillustrates a diagram of the configuration of a base station according to an embodiment.

As shown inFIG. 3I, the base station includes an RF processor3i-10, a baseband processor3i-20, a backhaul communication unit3i-30, a storage unit3i-40, and a controller3i-50. The controller3i-50may further include a multi-connection processor3i-52.

The RF processor3i-10performs a function of transmitting and receiving signals, such as band conversion and amplification of a signal, through a radio channel. That is, the RF processor3i-10up-converts a baseband signal provided from the baseband processor3i-20to an RF band signal to thus transmit the same through an antenna, and down-converts an RF band signal received through the antenna to a baseband signal. For example, the RF processor3i-10may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may have a plurality of antennas. In addition, the RF processor3i-10may include a plurality of RF chains. Further, the RF processor3i-10may perform beamforming. To perform beamforming, the RF processor3i-10may adjust the phases and magnitudes of signals transmitted and received through a plurality of antennas or antenna elements. The RF processor may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processor3i-20performs a function of conversion between a baseband signal and a bit string according to a physical layer specification of a first radio access technique. For example, in the case of data transmission, the baseband processor3i-20encodes and modulates transmission bit strings, thereby generating complex symbols. In addition, when receiving data, the baseband processor3i-20demodulates and decodes a baseband signal provided from the RF processor3i-10to thus recover reception bit strings. For example, in the case where an OFDM scheme is applied, when transmitting data, the baseband processor3i-20generates complex symbols by encoding and modulating transmission bit strings, maps the complex symbols to subcarriers, and then configures OFDM symbols through the IFFT operation and CP insertion. In addition, when receiving data, the baseband processor3i-20divides the baseband signal provided from the RF processor3i-10into OFDM symbol units, restores the signals mapped to the subcarriers through the FFT operation, and then restores reception bit strings through demodulation and decoding. The baseband processor3i-20and the RF processor3i-10transmit and receive signals as described above. Accordingly, the baseband processor3i-20and the RF processor3i-10may be referred to as a “transmitter”, a “receiver”, a “transceiver”, a “communication unit”, or a “wireless communication unit”.

The backhaul communication unit3i-30provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit3i-30converts a bit string, transmitted from the base station to another node, such as a secondary base station, a core network, etc., into a physical signal, and converts physical signals received from other nodes into bit strings.

The storage unit3i-40stores data such as fundamental programs, application programs, and configuration information for the operation of the base station. In particular, the storage unit3i-40may store information about bearers allocated to a connected terminal, a measurement result reported from a connected terminal, and the like. In addition, the storage unit3i-40may store information that is a criterion for determining whether a multi-connection is provided to the terminal or is released. In addition, the storage unit3i-40provides the stored data in response to a request from the controller3i-50.

The controller3i-50controls the overall operation of the base station. For example, the controller3i-50transmits and receives signals through the baseband processor3i-20and the RF processor3i-10or the backhaul communication unit3i-30. In addition, the controller3i-50records and reads data in and from the storage unit3i-40. To this end, the controller3i-50may include at least one processor.

The details in the block diagram $00of electronic device #01for supporting legacy network communication and 5G network communication described with reference toFIG. 1Hmay also be applied to the third embodiment.