Method and apparatus for supporting conditional ltm intra- base station / inter-base station in wireless communications system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates.

Description

Technology Field

[0001] The present disclosure relates to a wireless communication system, and more specifically, describes base station, terminal, and core network operations for supporting conditional LTM within or between base stations in a wireless mobile communication system. Background Technology

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, implementation in the terahertz band (e.g., the 3 terahertz (3 THz) band at 95 GHz) is being considered to achieve transmission speeds 50 times faster and ultra-low latency reduced to one-tenth compared to 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X (Vehicle-to-Everything), which helps autonomous vehicles make driving decisions and enhance user convenience based on their own location and status information transmitted by the vehicle; NR-U (New Radio Unlicensed), which aims for system operation in unlicensed bands to comply with various regulatory requirements; NR terminal low power consumption technology (UE Power Saving); Non-Terrestrial Network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

[0005] In addition, standardization is underway in the field of wireless interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes to expand network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) Handover, and 2-step Random Access (2-step RACH for NR) which simplifies random access procedures. Standardization is also underway in the field of system architecture / services for 5G baseline architectures (e.g., Service based Architecture, Service based Interface) to incorporate Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC), which provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas to guarantee coverage in the terahertz band of 6G mobile communication technology; metamaterial-based lenses and antennas; high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM); and Reconfigurable Intelligent Surface (RIS) technology to improve terahertz band signal coverage; as well as full-duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and Artificial Intelligence (AI) from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies. The problem to be solved

[0008] The objective of the present invention is to provide a method for conditional L1 / L2 Triggered Mobility (CLTM) of a terminal based on Layer 1 / Layer 2 signaling in a mobile communication system through embodiments.

[0009] Specifically, it can provide information that must be exchanged between base stations to distinguish the difference from existing Layer 1 / Layer 2 signaling-based handover and the difference between them.

[0010] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0011] The present invention, for solving the above-mentioned problems, is characterized in that a method for processing a control signal in a wireless communication system comprises: a step of receiving a first control signal transmitted from a base station; a step of processing the received first control signal; and a step of transmitting a second control signal generated based on the processing to the base station. Effects of the invention

[0012] According to one embodiment of the present invention, conditional LTM within or between base stations can be provided more effectively. Brief explanation of the drawing

[0013] Figure 1 is a diagram illustrating an example of a next-generation mobile communication system structure. FIG. 2 is a signal flow diagram in the process (Intra-DU CLTM) in which a terminal according to one embodiment performs cell movement within one DU in a separated base station based on Layer 1 / Layer 2 signaling. FIG. 3 is a signal flow diagram in the process (Inter-DU CLTM) in which a terminal according to one embodiment performs conditional cell movement from the DU to which the current serving cell belongs to another DU in a separated base station based on Layer 1 / Layer 2 signaling. FIG. 4 is a block diagram showing an example of the configuration of a RAN Node according to an embodiment of the present invention. FIG. 5 is a block diagram illustrating an example of the structure of a terminal (UE) according to one embodiment of the present invention. Specific details for implementing the invention

[0014] In the following description of the present invention, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions could unnecessarily obscure the essence of the invention. Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these definitions may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification.

[0015] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] FIG. 1 is a drawing illustrating an example of a next-generation mobile communication system structure. That is, FIG. 1 is a drawing illustrating an example of a next-generation mobile communication system structure to which embodiments of the present disclosure can be applied.

[0018] Referring to FIG. 1, the RAN (Radio Access Network) Node (1-100, 1-200) specified in this structure may refer to a mobile communication base station, such as an LTE (Long Term Evolution) eNB or NR gNB, connected to a mobile communication core network (Core Network, CN) (1-400), such as an EPC (Evolved Packet Core) or 5GC (5G Core Network). Additionally, the RAN Node (1-100, 1-200) may be separated into a CU (Centralized Unit) and a Distributed Unit (DU), and the CU may be further separated into a CU-CP (Control Plane) and a CU-UP (User Plane). Referring to FIG. 1, the RAN Node (1-100) may refer to a Source RAN Node, and the RAN Node (1-200) may refer to a Target RAN Node.

[0019] According to one embodiment, a single RAN Node may be composed of one or more CU-CPs, one or more CU-UPs, and one or more DUs (1-110, 1-120). Additionally, the CU-CPs, CU-UPs, and DUs constituting a single RAN Node may be configured together. For example, a single RAN Node may be composed of a CU in which a CU-CP and a CU-UP are implemented together, and a DU. In another RAN Node, a CU-CP and a DU are implemented together, and a CU-UP is configured separately. Another RAN Node may be configured in the form of an integrated base station in which a CU-CP, a CU-UP, and a DU are implemented together. A single RAN Node may be configured in any other combination other than the examples described above.

[0020] According to one embodiment, the CU and the DU can support their respective base station functions separately. For example, the CU may support the RRC (Radio Resource Control) / PDCP (Packet Data Convergence Protocol) layer, and the DU may support the RLC (Radio Link Control) / MAC (Medium Access Control) / PHY / RF (Radio Frequency) layer. Additionally, the CU and the DU can be connected through an interface between internal base station functions, such as a W1 or F1 interface.

[0021] According to one embodiment, the CU can be divided into CU-CP and CU-UP. For example, the CU-CP may support an RRC / PDCP (for RRC) layer, and the CU-UP may support a PDCP (for user data transmission) layer, and the CU-CP and CU-UP may be connected through an interface between internal base station functions such as an E1 interface.

[0022] According to one embodiment, base stations may be constructed in an integrated or separated structure, enabling connections between integrated base stations, between separated base stations, and between an integrated base station and a separated base station. RAN Nodes may be connected via an inter-base station interface such as an X2 or Xn interface. Additionally, a RAN Node and a core network may be connected via a base station-core network interface such as an S1 or NG interface. The technology proposed in this disclosure may be applied when a terminal (1-300) moves between cells within a single DU (Intra-DU) or moves from DU 1 (1-110) to DU 2 (1-120) (Inter-DU) in a separated base station. Furthermore, it may be applied when a handover occurs between base stations when the terminal (1-300) moves to a Target RAN Node while connected to a Source RAN Node, regardless of whether it is an integrated base station or a separated base station.

[0024] FIG. 2 is a signal flow diagram in the process (Intra-DU CLTM) in which a terminal according to one embodiment performs cell movement within one DU in a separated base station based on Layer 1 / Layer 2 signaling.

[0025] Referring to FIG. 2, in step 100, the terminal (10) is connected to the separated base station gNB-DU (20) and gNB-CU (30) and can transmit and receive user packets through 5GC (40). In step 200, the terminal (10) can perform Layer 3 measurements based on signals transmitted by the base stations according to information set by the base stations (20, 30) and transmit the measurement information to the gNB-DU (20). In step 200, the gNB-DU (20), having received Layer 3 measurement information from the terminal (10), can transmit it to the gNB-CU (30). Subsequently, in step 210, the gNB-CU (30) can determine whether to set up a conditional handover (Conditional L1 / L2 Triggered Mobility, CLTM) based on Layer 1 / Layer 2 signaling for the terminal (10). When it is decided to perform a conditional handover based on Layer 1 / Layer 2 signaling, the terminal determines candidate target cells and gNBs containing the target cells to which the terminal can perform the handover. This embodiment relates to a conditional handover situation based on Layer 1 / Layer 2 signaling in an intra-DU situation, where all of the candidate target cells are under the management of the gNB-DU (20) to which the terminal is connected.

[0026] The gNB-CU (30) can send a UE CONTEXT MODIFICATION REQUEST message to the gNB-DU (20) to set up a handover based on Layer 1 / Layer 2 signaling in step 220 to the target cell determined in step 210. At this time, if there are multiple candidate target cells, the UE CONTEXT MODIFICATION REQUEST message may be sent multiple times, and each message may be distinguished by cell ID information. The UE CONTEXT MODIFICATION REQUEST message may include an indicator that it is for setting up a handover based on Layer 1 / Layer 2 signaling and information for setting up CLTM. At this time, the indicator may be an existing LTM (L1 / L2 Triggered Mobility) Indicator with a codepoint inserted to distinguish it as a Conditional LTM, or a new indicator may be defined specifically for CLTM. In addition, just as the LTM ID and cell ID mapping information given to the terminal (10) in the existing LTM is transmitted through the corresponding message, the CLTM can also contain the CLTM ID and cell ID mapping information given to the terminal (10). The above details will be explained in detail below along with the message.

[0027] Upon receiving the UE CONTEXT MODIFICATION REQUEST message, the gNB-DU (20) can determine in step 230 whether to accept the conditional handover setting based on Layer 1 / Layer 2 signaling, and if it decides to accept it, it can send the UE CONTEXT MODIFICATION RESPONSE message to the gNB-CU (30). The UE CONTEXT MODIFICATION RESPONSE message may include RRC setting values ​​related to the cell that decided to accept and Layer 1 measurement value information that the terminal (10) must measure, and may contain conditions for executing CLTM. These conditions are generated by the gNB-DU containing the candidate cell and transmitted to the gNB-CU, and may ultimately be included in the RRC message transmitted to the terminal (10). When the Layer 1 measurement result matches the execution conditions, the terminal (10) can perform a handover without instructions from the base station.

[0028] At this time, as described above, if there are multiple target cells, the UE CONTEXT MODIFICATION RESPONSE message corresponding to step 230 may also be transmitted multiple times.

[0029] The gNB-CU (30), having exchanged information with all candidate target cells, can send a message (UE CONTEXT MODIFICATION REQUEST, 240) containing Layer 1 measurement information related to the target cell included as the final candidate to the gNB-DU (20). The Layer 1 measurement value included in the UE CONTEXT MODIFICATION REQUEST message (240) can be at least one of SSB or CSI-RS.

[0030] Upon receiving the corresponding UE CONTEXT MODIFICATION REQUEST message (240), the gNB-DU (20) can generate a lower layer RRC, put it into the UE CONTEXT MODIFICATION RESPONSE (250), and transmit it to the gNB-CU (30). This operation is intended to generate Layer 1 measurement information related to the candidate cell when performing a conditional handover based on Layer 1 / Layer 2 signaling based on the serving cell to which the current terminal (10) is connected. This information is included in the RRC of step 250. Additionally, it is intended to collect the settings related to the CLTM execution conditions received from each candidate cell and transmit them to the gNB-DU.

[0031] Based on the lower layer RRC value received from gNB-DU (20), gNB-CU (30) can generate an RRCReconfiguration message to be delivered to the terminal (10) and send it to gNB-DU (20) by placing it in a DL RRC TRANSFER MESSAGE (step 260). gNB-DU (20) can send the received RRCReconfiguration message to the terminal (10) in step 270. In response to this, the terminal (10) can send an RRCReconfigurationComplete message to gNB-DU (20) in step 280. The RRCReconfigurationComplete message can finally reach gNB-CU (30) by placing it in a UL RRC TRANSFER MESSAGE in step 290.

[0032] After going through the process described above, the preparation process for Layer 1 / Layer 2 signaling-based conditional handover is completed.

[0033] After completing the preparation process, the terminal (10) can report Layer 1 measurement information to the gNB-DU (20) according to the setting values ​​in the process described above (step 300). At the same time as reporting the measurement information, the terminal (10) can determine whether the Layer 1 measurement information meets the CLTM execution conditions received from the gNB-DU (20) (step 310). If it meets the CLTM execution conditions, it can hand over to the corresponding cell (step 320).

[0035] FIG. 3 is a signal flow diagram in the process (Inter-DU CLTM) in which a terminal according to one embodiment performs conditional cell movement from the DU to which the current serving cell belongs to another DU in a separated base station based on Layer 1 / Layer 2 signaling.

[0036] Referring to FIG. 3, in step 100, the terminal (10) is connected to a separated base station Source gNB-DU (20, hereinafter S-DU) and a gNB-CU (40, hereinafter CU), and can transmit and receive user packets through 5GC (50). In step 200, the terminal (10) can perform Layer 3 measurements based on signals transmitted by base stations according to information set by the base stations (20, 40), and transmit the measurement information to the S-DU (20). In step 200, the S-DU (20), having received Layer 3 measurement information from the terminal (10), can transmit it to the CU (40). Subsequently, in step 210, the CU (40) can determine whether to set up the terminal (10) for performing a handover (LTM: L1 / L2 Triggered Mobility) based on Layer 1 / Layer 2 signaling. When it is decided to perform a conditional handover based on Layer 1 / Layer 2 signaling, the terminal determines a candidate target cell and gNBs containing the target cell for the conditional handover. This embodiment relates to a conditional handover situation based on Layer 1 / Layer 2 signaling in an inter-DU situation, where the candidate target cell is under the management of a Candidate gNB-DU (30, hereinafter C-DU) rather than the S-DU (20) to which the terminal is connected.

[0037] The gNB-CU (40) can send a UE CONTEXT SETUP REQUEST message to the C-DU (30) to set up a handover based on Layer 1 / Layer 2 signaling in step 220 for the target cell determined in step 210. If there are multiple candidate target cells, the UE CONTEXT SETUP REQUEST message may be sent multiple times, and each message may be distinguished by cell ID information. The UE CONTEXT SETUP REQUEST message may include an indicator indicating that it is for setting up a conditional handover based on Layer 1 / Layer 2 signaling, and information for setting up CLTM. The indicator may be an existing LTM (L1 / L2 Triggered Mobility) Indicator with a codepoint inserted to distinguish it as a Conditional LTM, or a new indicator may be defined specifically for CLTM. In addition, just as the LTM ID and cell ID mapping information given to the terminal (10) in the existing LTM is transmitted through the corresponding message, the CLTM can also contain the CLTM ID and cell ID mapping information given to the terminal (10). The C-DU (30) that receives the UE CONTEXT SETUP REQUEST message can decide whether to accept the conditional handover setting based on Layer 1 / Layer 2 signaling in step 230. If it is decided to accept, it can send the UE CONTEXT SETUP RESPONSE message to the gNB-CU (40). The UE CONTEXT SETUP RESPONSE message may include RRC setting values ​​related to the cell decided to accept and Layer 1 measurement value information that the terminal (10) must measure, and contains conditions for executing the CLTM. These conditions are generated by the gNB-DU containing the candidate cell and transmitted to the gNB-CU, and can ultimately be included in the RRC message transmitted to the terminal (10).The terminal (10) can perform a handover without instructions from the base station when the Layer 1 measurement result matches the corresponding execution condition. The above description will be explained in detail below with a message, just like the intra-DU situation of FIG. 2.

[0038] .

[0039] At this time, as described above, if there are multiple target cells, the UE CONTEXT SETUP RESPONSE message corresponding to step 230 may also be transmitted multiple times.

[0040] The gNB-CU (40), having exchanged information with all candidate target cells, can send a message (UE CONTEXT MODIFICATION REQUEST, 240) containing Layer 1 measurement information related to the target cell included as the final candidate to the S-DU (20). The Layer 1 measurement value included in the UE CONTEXT MODIFICATION REQUEST message (240) can be an SSB or a CSI-RS, or both.

[0041] The S-DU (20) that receives the corresponding UE CONTEXT MODIFICATION REQUEST message (240) can generate a lower layer RRC, put it in the UE CONTEXT MODIFICATION RESPONSE (250), and transmit it to the gNB-CU (40). This operation is intended to generate Layer 1 measurement information related to the candidate cell when performing a handover based on Layer 1 / Layer 2 signaling based on the serving cell to which the current terminal (10) is connected. This information is included in the RRC of step 250. Additionally, it is intended to collect the settings related to the CLTM execution conditions received from each candidate cell and transmit them to the gNB-DU.

[0042] Based on the lower layer RRC value received from the S-DU (20), the gNB-CU (40) can generate an RRCReconfiguration message to be delivered to the terminal (10) and send it to the S-DU (20) by placing it in a DL RRC TRANSFER MESSAGE (step 260). The S-DU (20) can send the received RRCReconfiguration message to the terminal (10) in step 270. In response to this, the terminal (10) can send an RRCReconfigurationComplete message to the S-DU (20) in step 280. The RRCReconfigurationComplete message can finally reach the gNB-CU (30) by placing it in a UL RRC TRANSFER MESSAGE in step 290.

[0043] After going through the process described above, the preparation process for Layer 1 / Layer 2 signaling-based conditional handover is completed.

[0044] After completing the preparation process, the terminal (10) can report Layer 1 measurement information to the S-DU (20) according to the setting values ​​in the process described above (step 300). At the same time as reporting the measurement information, the terminal (10) can determine whether the Layer 1 measurement information meets the CLTM execution conditions received from the S-DU (20) (step 310). If it meets the CLTM execution conditions, it can hand over to the corresponding cell (step 320).

[0046] As described above in FIG. 2 (Intra-DU LTM) and FIG. 3 (Inter-DU LTM), an indicator for distinguishing between CLTM and LTM, a mapping relationship between CLTM ID and Cell ID, and a message including CLTM execution conditions are described. For example, the UE CONTEXT SETUP REQUEST message may be as follows.

[0047]

[0048] The UE CONTEXT SETUP REQUEST message is a message that the gNB-CU sends to the candidate gNB-DU during the Inter-DU CLTM preparation process. It includes an indicator to indicate that the message is intended to prepare the CLTM. This can be indicated by adding a new identifier, conditional, to the existing LTM Indicator (10a). Additionally, another identifier, both, may be included to account for cases where the LTM and CLTM are set simultaneously.

[0049] Another way to use indicators is to define a new CLTM Indicator and use it together with the existing LTM Indicator. In this case, to set both LTM and CLTM simultaneously, you can send a message that includes both indicators.

[0050] In addition, the UE CONTEXT SETUP RESPONSE message in response to this may be as follows.

[0051]

[0052] The UE CONTEXT SETUP RESPONSE message may include CLTM execution conditions generated by the gNB-DU. The execution conditions may be included in the existing LTM Configuration or in a separate CLTM Configuration. The CLTM execution conditions are transmitted to the gNB-CU and finally sent to the terminal, and the terminal can observe Layer 1 measurements and, when they match the execution conditions, perform a handover on its own without instructions from the base station.

[0053] In addition, the UE CONTEXT MODIFICATION REQUEST message may be as follows.

[0054]

[0056] The UE CONTEXT MODIFICATION REQUEST message is transmitted by the gNB-CU to the candidate gNB-DU during the Intra-DU CLTM preparation process. It is also used to change configuration values ​​during the Inter-DU and Intra-DU CLTM preparation processes. It includes an indicator to signal that the message is intended for preparing a CLTM; this can be indicated by adding a new identifier, 'conditional', to the existing LTM Indicator. Additionally, another identifier, 'both', may be included to account for cases where LTM and CLTM are configured simultaneously.

[0057] Another way to use indicators is to define a new CLTM Indicator and use it together with the existing LTM Indicator. In this case, to set both LTM and CLTM simultaneously, you can send a message that includes both indicators.

[0058] The UE CONTEXT MODIFICATION RESPONSE message in response to this may be as follows.

[0059]

[0060] The UE CONTEXT MODIFICATION RESPONSE message may include CLTM execution conditions generated by the gNB-DU. The execution conditions may be included in the existing LTM Configuration or in a separate CLTM Configuration. The CLTM execution conditions are transmitted to the gNB-CU and finally sent to the terminal, and the terminal can observe Layer 1 measurements and, when they match the execution conditions, perform a handover on its own without instructions from the base station.

[0061] Finally, the ID assigned to the corresponding CLTM configuration is one per candidate cell and may newly include an IE indicating the mapping relationship between the CLTM ID and the cell ID. This IE is included in the UE CONTEXT SETUP REQUEST message and the UE CONTEXT MODIFICATION REQUEST message, provided to the gNB-DU, and can be used to distinguish CLTM configuration values. For example, the CLTM Configuration ID Mapping List may be as follows.

[0062]

[0063] FIG. 4 is a block diagram showing an example of the configuration of a RAN Node according to an embodiment of the present invention. As shown in the figure, the RAN Node is configured to include an RF processing unit (10), a baseband processing unit (20), a backhaul communication unit (30), a storage unit (40), and a control unit (50). When the RAN Node is separated into a CU (Central Unit) and a DU (Distributed Unit), a block diagram different from that included in FIG. 4 may be configured. For example, the RF processing unit (10) and the baseband processing unit (20) may be configured to include a control unit, a storage unit, and a backhaul communication unit for communication with the CU in the DU, and for example, the backhaul communication unit (30) may be configured to include a control unit, a storage unit, and a backhaul communication unit for communication with the DU in the CU.

[0064] The RF processing unit (10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (10) upconverts the baseband signal provided by the baseband processing unit (20) into an RF band signal, transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although only one antenna is shown in the drawing, the first connection node may be equipped with multiple antennas. Additionally, the RF processing unit (10) may include multiple RF chains. Furthermore, the RF processing unit (10) may perform beamforming. For beamforming, the RF processing unit (10) may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The above RF processing unit can perform down-to-down MIMO operation by transmitting one or more layers.

[0065] The baseband processing unit (20) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence. In addition, when receiving data, the baseband processing unit (20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (10). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT operation and CP insertion. Additionally, upon receiving data, the baseband processing unit (20) divides the baseband signal provided by the RF processing unit (10) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operations, and then restores the received bit sequence through demodulation and decoding. The baseband processing unit (20) and the RF processing unit (10) transmit and receive signals as described above. Accordingly, the baseband processing unit (20) and the RF processing unit (10) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a communication unit, or a wireless communication unit.

[0066] The backhaul communication unit (30) provides an interface for communicating with other nodes within the network. The backhaul communication unit (30) converts a bit sequence transmitted from the RAN Node to another node, e.g., an auxiliary base station, a core network, etc., into a physical signal, and converts a physical signal received from the other node into a bit sequence.

[0067] The storage unit (40) stores data such as basic programs, application programs, and configuration information for the operation of the RAN Node. In particular, the storage unit (40) can store information regarding bearers assigned to connected terminals, measurement results reported from connected terminals, etc. Additionally, the storage unit (40) can store information serving as a criterion for determining whether to provide or disconnect multiple connections to the terminals. Furthermore, the storage unit (40) provides the stored data upon a request from the control unit (50).

[0068] The control unit (50) controls the overall operations of the RAN Node. For example, the control unit (50) transmits and receives signals through the baseband processing unit (20) and the RF processing unit (10) or through the backhaul communication unit (30). In addition, the control unit (50) writes and reads data to and from the storage unit (40). To this end, the control unit (50) may include at least one processor. In addition, the control unit (50) may be used to control the overall operations of the RAN.

[0070] FIG. 5 is a block diagram illustrating an example of the structure of a terminal (UE) according to an embodiment of the present invention. Referring to the figure, the terminal includes an RF (Radio Frequency) processing unit (10), a baseband processing unit (20), a storage unit (30), and a control unit (40). The RF processing unit (10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (10) up-converts a baseband signal provided by the baseband processing unit (20) into an RF band signal and transmits it through an antenna, and down-converts an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), etc. Although only one antenna is shown in the figure, the terminal may be equipped with multiple antennas. Additionally, the RF processing unit (10) may include a plurality of RF chains. Furthermore, the RF processing unit (10) may perform beamforming. For beamforming, the RF processing unit (10) may adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. Additionally, the RF processing unit may perform MIMO and may receive multiple layers when performing MIMO operation.

[0071] The baseband processing unit (20) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence. In addition, when receiving data, the baseband processing unit (20) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (10). For example, in the case of following the orthogonal frequency division multiplexing (OFDM) method, when transmitting data, the baseband processing unit (20) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through inverse fast Fourier transform (IFFT) operations and cyclic prefix (CP) insertion. Additionally, upon receiving data, the baseband processing unit (20) divides the baseband signal provided by the RF processing unit (10) into OFDM symbol units, restores the signals mapped to subcarriers through a fast Fourier transform (FFT), and then restores the received bit sequence through demodulation and decoding.

[0072] The baseband processing unit (20) and the RF processing unit (10) transmit and receive signals as described above. Accordingly, the baseband processing unit (20) and the RF processing unit (10) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, or a communication unit. Furthermore, at least one of the baseband processing unit (20) and the RF processing unit (10) may include a plurality of communication modules to support a plurality of different wireless access technologies. Additionally, at least one of the baseband processing unit (20) and the RF processing unit (10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. In addition, the above different frequency bands may include super high frequency (SHF) bands (e.g., 2 NRHz, NRHz) and millimeter wave (e.g., 60 GHz) bands.

[0073] The storage unit (30) stores data such as a basic program, an application program, and setting information for the operation of the terminal. The storage unit (30) also provides the stored data in response to a request from the control unit (40).

[0074] The control unit (40) controls the overall operations of the terminal. For example, the control unit (40) transmits and receives signals through the baseband processing unit (20) and the RF processing unit (10). Additionally, the control unit (40) writes and reads data to and from the storage unit (40). To this end, the control unit (40) may include at least one processor. For example, the control unit (40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as applications.

Claims

Claim 1 A control signal processing method in a wireless communication system, characterized by comprising: a step of receiving a first control signal transmitted from a base station; a step of processing the received first control signal; and a step of transmitting a second control signal generated based on the processing to the base station.

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