Terminal, base station, and communication method

Abstract

This terminal comprises: a reception unit that receives information indicating a frequency band in which is set a second carrier for which waiting is performed before accessing a first carrier; and a control unit that searches for the second carrier in the frequency band indicated by the information indicating the frequency band.

Description

Terminal, Base Station, and Communication Method

[0001] The present disclosure relates to a terminal that performs initial access, a base station, and a communication method.

[0002] The 3rd Generation Partnership Project (3GPP (registered trademark)) is standardizing the 5th generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and is also promoting the standardization of next-generation mobile communication systems called Beyond 5G, 5G Evolution or 6G.

[0003] In 5G / NR initial access, the terminal scans the frequency bands supported by the terminal after power-on and searches for cells using synchronization signals. Then, based on the information regarding the PLMN (Public Land Mobile Network) / SNPN (Standalone Non Public Network) included in SIB1 notified by the searched cell, the terminal selects a PLMN and / or SNPN (hereinafter, PLMN / SNPN), and selects or reselects a cell to camp on (also called wait) from the cells of the selected PLMN / SNPN. The terminal receives the provision of communication services in the selected or reselected cell (Non-Patent Document 1).

[0004] 3GPP TS 38.304 V18.3.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; User Equipment (UE) procedures in Idle mode and RRC Inactive state (Release 18), 3GPP, September 2024

[0005] As mentioned above, in existing wireless communication systems, terminals receive communication services from the cell where they are on standby. However, in future wireless communication systems such as 6G, there is consideration to separating the cell where the terminal is on standby from the cell from which the terminal receives communication services. The carrier of the cell where the terminal is on standby may be called the perch carrier, and the carrier of the cell that the terminal accesses to receive communication services may be called the anchor carrier.

[0006] When a perch carrier is introduced, it is conceivable that a terminal would first access the perch carrier after power-on, before accessing the anchor carrier. However, perch carriers can be configured in a limited number of frequency bands, and conventional search methods are inefficient because they search all frequency bands.

[0007] Therefore, this disclosure is made in view of these circumstances and aims to provide a terminal, base station, communication method, and communication system that enable terminals to efficiently search for a perch carrier when a perch carrier is introduced.

[0008] One aspect of the present disclosure is a terminal (200) comprising a receiving unit (220) that receives information indicating a frequency band on which a second carrier that waits before accessing a first carrier is set, and a control unit (230) that searches for the second carrier in the frequency band indicated by the information indicating the frequency band.

[0009] One aspect of the present disclosure is a base station (100) comprising a transmitting unit (110) that transmits information indicating a frequency band on which a second carrier is set to be on standby before a terminal accesses a first carrier, and a control unit (120) that causes the information indicating the frequency band to be transmitted as broadcast information to multiple terminals or as information to a specific terminal.

[0010] One aspect of the present disclosure is a communication method for a terminal (200) that includes the steps of: receiving information indicating a frequency band on which a second carrier that will be on standby before accessing a first carrier is set; and searching for the second carrier in the frequency band indicated by the frequency band information.

[0011] Figure 1 is an overall schematic diagram of a wireless communication system. Figure 2 is a diagram showing the frequency range used in the wireless communication system. Figure 3 is a diagram showing an example of the configuration of wireless frames, subframes, slots, and symbols used in the wireless communication system. Figure 4 is a diagram showing an example of a carrier type. Figure 5 is a functional block diagram of a base station. Figure 6 is a functional block diagram of a terminal. Figure 7 is a diagram showing an example of frequency band information (part 1). Figure 8 is a diagram showing an example of frequency band information (part 2). Figure 9 is a diagram showing the flow for obtaining frequency band information from the network. Figure 10 is a diagram showing an example of the hardware configuration of a base station and a terminal. Figure 11 is a diagram showing an example of the configuration of a vehicle.

[0012] The embodiments will be described below with reference to the drawings. Note that identical or similar reference numerals are used to denote the same functions and components, and their descriptions will be omitted as appropriate.

[0013] (1) Overall schematic diagram 1 of the wireless communication system is an overall schematic diagram of the wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system that conforms to a method called Beyond 5G, 5G Evolution, or 6G, and includes a Next Generation-Radio Access Network 20 (hereinafter referred to as NG-RAN20) and a terminal 200 (also referred to as User Equipment 200, hereinafter referred to as UE200).

[0014] Furthermore, the wireless communication system 10 may partially include a wireless communication system that conforms to a method called 5G New Radio (NR), or a wireless communication system that conforms to a method called Long Term Evolution (LTE) or 4G. The wireless communication system 10 may support functions related to the Industrial Internet of Things (IIoT) and URLLC (Ultra-Reliable and Low Latency Communications).

[0015] NG-RAN20 includes multiple base stations 100 (hereinafter also referred to as BS (Base Station) 100). The base stations 100 may include gNB (gNodeB), eNB (eNodeB), etc., and the specific configuration of the wireless communication system 10, including the number of UEs, is not limited to the example shown in Figure 1.

[0016] Furthermore, base station 100 may employ a fronthaul (FH) interface as defined by O-RAN (Open Radio Access Network Alliance). Base station 100 may include O-DU (O-RAN Distributed Unit) and O-RU (O-RAN Radio Unit). Base station 100 can function as a type of NG-RAN node.

[0017] NG-RAN20 is connected to a 6G-compliant core network (6GC, not shown). NG-RAN20 and 6GC may also be simply referred to as "the network (NW)". In 6GC, the concept of CUPS (Control and User Plane Separation), where the functions of the user plane and control plane are clearly separated, may be introduced. Furthermore, NG-RAN20 may also be connected to a 4G-compliant core network (4GC) or a 5G-compliant core network (5GC), in addition to 6GC.

[0018] Base station 100 is a 6G-compliant wireless base station and performs 6G-compliant wireless communication with UE200. Base station 100 may include a CU (Central Unit) and a DU (Distributed Unit), and the DU may be installed separately from the CU in a geographically different location. One or more DUs may be connected to the CU. Furthermore, base stations 100 (CUs) may be connected by an Xn interface, and CUs and DUs may be connected by an F1 interface (F1-AP, etc.). In this embodiment, the CU may be called a communication device or a central device, etc. Also, the DU may be called a distributed device, etc.

[0019] The base station 100 and UE200 can support carrier aggregation (CA), which combines multiple component carriers (CCs), and dual connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN Nodes, using Massive MIMO, which generates a more directional beam by controlling radio signals transmitted from multiple antenna elements.

[0020] The type of data center (DC) may be Multi-RAT Dual Connectivity (MR-DC), which utilizes multiple radio access technologies, or Dual Connectivity, which utilizes only 6G. For example, one of the base stations 100 may constitute a master node (MN), and one or more other base stations 100 may constitute secondary nodes (SN).

[0021] The UE200 is a 6G-compatible terminal capable of communication in accordance with 6G standards. A 6G-compatible terminal may also support communication functions in accordance with existing technologies (4G and / or 5G).

[0022] Furthermore, the wireless communication system 10 may support multiple frequency ranges (FRs). That is, as shown in Figure 2, it may support the following FRs: • FR1: 410 MHz to 7.125 GHz • FR2-1: 24.25 GHz to 52.6 GHz • FR2-2: Over 52.6 GHz to 71 GHz

[0023] In FR1, a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz may be used. In FR2-1, an SCS of 60 or 120 kHz (or 240 kHz) and a BW of 50 to 400 MHz may be used.

[0024] In FR2-2, to avoid an increase in phase noise, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be applied.

[0025] Furthermore, the wireless access network 20 of the wireless communication system 10 may also support the following frequency ranges (FRs) in addition to those described in Figure 2: • FRx-1: 7.125GHz to 20GHz • FRx-2: 92GHz to 300GHz

[0026] Furthermore, as shown in Figure 3, one slot in the wireless communication system 10 consists of 14 symbols. If this configuration is maintained, the larger (wider) the SCS becomes, the shorter the symbol period (and slot period). Note that the SCS is not limited to the frequencies shown in Figure 3, and may be other frequencies such as 480 kHz or 960 kHz.

[0027] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14; for example, it could be 28 or 56 symbols. In addition, the number of slots per subframe may vary depending on the SCS.

[0028] (2) Carrier configuration diagram 4 is a diagram showing an example of a carrier type. The wireless access network 20 in Figure 1 may support the carrier types shown in Figure 4.

[0029] Referring to Figure 4, we will first explain the perch carrier. One of the purposes of the perch carrier is to enable data communication on the anchor carrier as needed (on demand). In other words, a terminal can access the anchor carrier when data is generated, the data carrier as needed, and the perch carrier otherwise. This enables Network Energy Saving (NES) of the network. Note that the term "access" may be interpreted interchangeably with the terms "cell selection" or "cell re-selection".

[0030] A perch carrier may be understood as a carrier having at least one of the following features, for example:

[0031] - It is a carrier accessible to all devices.

[0032] - The carrier is accessible regardless of the terminal type or usage environment (however, some terminals that meet different conditions than the type or usage environment may be configured to be inaccessible). Terminal types include, for example, enhanced Mobile BroadBand (eMBB) terminals, Reduced Capability (RedCap) terminals, Unmanned Aerial Vehicle (UAV) terminals, XR terminals, NTN terminals, IoT terminals, Industrial IoT terminals, NarrowBand IoT (NB-IoT) terminals, Low-Power Wake-Up Signal (LPWUS) terminals, and Small Data Transmission (SDT) terminals. Terminal usage environments include, for example, access type (e.g., 3GPP, non-3GPP), use case (e.g., Immersive Communication, Ubiquitous Connectivity), and service type (e.g., Ultra-Reliable and Low Latency Communications (URLLC), Vehicle to X (V2X), Multicast and Broadcast Service (MBS), Broadcast Service).

[0033] This refers to a carrier that is accessible regardless of whether data communication is enabled or disabled (a carrier not intended for data communication). Data communication primarily refers to the transmission and reception of user data and traffic data processed by the U-Plane (User-Plane). User data may include voice calls, but does not exclude control data. Hereafter, this will also be simply referred to as "communication."

[0034] - This is a carrier on which synchronization signals (SS: Synchronization Signal) and / or system information are transmitted. Synchronization signals may include, for example, PSS (Primary Synchronization Signal) and / or SSS (Secondary Synchronization Signal). System information may include, for example, MIB (Master Information Block) transmitted on a broadcast channel (e.g., PBCH (Physical Broadcast Channel)) and / or SIB (e.g., SIB1) transmitted on a downlink shared channel (e.g., PDSCH (Physical Downlink Shared Channel)). Since system information is broadcast on the broadcast channel and / or downlink shared channel, it may also be called broadcast information. Furthermore, the block containing the synchronization signals and broadcast channels may be called SSB (synchronization signal block) or SS / PBCH (synchronization signal / physical broadcast channel block), etc. Thus, the perch carrier can also be described as a carrier on which control information (e.g., signals and / or information for initial access) is transmitted. System information transmitted and received on the perch carrier may include information about other carriers (data carrier (Band C), anchor carrier (Bands A and B) in the diagram). Information about other carriers is, for example, information that allows a terminal accessing the perch carrier to select another carrier (to perform initial access to another carrier). Also, if another carrier transitions to Network Energy Saving mode (NES mode), information about the other carrier may include information about NES mode. Information about NES mode is, for example, Cell DTX config (periodicity), Cell DRX config (periodicity), and SSB periodicity.

[0035] - The perch carrier may be in a lower frequency band (e.g., 700MHz, 800MHz, or 2GHz) than the data carrier (Band C) that transmits and receives data, or the anchor carrier (Bands A and B) that transmits and receives control information (and data). Due to frequency characteristics, coverage is greater in the lower frequency band, so coverage can be ensured by using a carrier in a lower frequency band than the anchor carrier as the perch carrier. On the other hand, by using a carrier in a higher frequency band than the perch carrier as the anchor carrier, a wider bandwidth can be ensured, thereby improving throughput. In this way, by combining the perch carrier and the anchor carrier, coverage can be ensured and throughput can be improved.

[0036] One use case for perch carriers and anchor carriers is to use a wideband frequency band with higher frequencies as an anchor carrier to support high-speed, high-capacity communication services such as XR (Cross Reality) terminals. However, because such high frequencies are directional, they are susceptible to reflection, requiring beam sweeping or the application of multiple beams, which increases network power consumption. Therefore, when providing high-speed, high-capacity communication services to terminals, a high-frequency band can be provided (turned on) as the anchor carrier. However, when not providing high-speed, high-capacity communication services to terminals, the high-frequency band can not be provided as the anchor carrier (turned off), and the terminals can be kept on standby with a perch carrier on a lower frequency band. By setting the perch carrier to a lower frequency band, coverage can be easily ensured compared to high frequencies because lower frequencies have the property of bending around, and network power consumption can also be reduced. In this way, perch carriers and anchor carriers are also suitable for the introduction of NES (Network Energy Saving).

[0037] A perch carrier may also be called a perch cell or perch band. In embodiments, "camping on" via a perch carrier may be used interchangeably with "camping on" in a perch cell or perch band. "Waiting" may also be used to mean waiting for communication. Furthermore, "waiting" may also mean "camping on." The state of a listening UE may be understood as a state where the RRC connection is not established or is suspended, such as an idle state (e.g., RRC_Idle) or an inactive state (e.g., RRC_Inactive).

[0038] A perch carrier may be recognizable by the terminal by default, or it may be configured by the network (base station). For example, a perch carrier may be assigned to a frequency band where coverage is relatively easy to ensure. A perch carrier may also be understood as a perch carrier group consisting of multiple perch carriers.

[0039] The anchor carrier is a carrier that transmits and receives control information (and data), and may be assigned to a higher frequency band than the perch carrier (e.g., Band A or Band B, such as the 3.7GHz band). In contrast, the data carrier is a carrier that transmits and receives data, and may be assigned to an even higher frequency band than the anchor carrier, such as Band C. These carriers may be used differently depending on the type of terminal and use case. For example, when an XR terminal or UE uses an XR service, it may transition from the perch carrier to an anchor carrier in Band A or B with a higher frequency, or to a data carrier in Band C, perform a RACH, and enter a connected state (e.g., RRC_Connected state).

[0040] Also, in the embodiment, the anchor carrier is a carrier having the role of a PCC (Primary Component Carrier) or a PCell (Primary Cell), and the data carrier may be considered as a carrier having the role of an SCC (Secondary Component Carrier).

[0041] Note that the terms "cell", "frequency", "frequency band", "band", and "carrier" may be read interchangeably with each other.

[0042] (3) Functional Block Configuration of the Wireless Communication System (3.1) Functional Block Configuration of the Base Station As shown in FIG. 5, the base station 100 includes a wireless communication unit 110, a frequency band information providing unit 120, and a control unit 130.

[0043] The wireless communication unit 110 transmits and receives wireless signals conforming to 6G to and from the UE 200. The wireless signals include channels and reference signals.

[0044] The wireless communication unit 110 transmits and receives wireless signals via a control channel or a data channel. The control channel includes a Physical Uplink Control Channel (PUCCH), a Physical Downlink Control Channel (PDCCH), a Physical Random Access Channel (PRACH), a Physical Broadcast Channel (PBCH), etc. Also, the data channel includes a Physical Uplink Shared Channel (PUSCH), a Physical Downlink Shared Channel (PDSCH), etc. Data may mean data transmitted via the data channel. Also, the reference signals include a Demodulation Reference Signal (DMRS), a Phase Tracking Reference Signal (PTRS), a Channel State Information-Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS).

[0045] The wireless communication unit 110 can transmit one or more pieces of notification information. The notification information may be a master information block (MIB) or a system information block (SIB). The wireless communication unit 110 transmits a paging message to the UE 200. The wireless communication unit 110 receives a request in the initial access from the UE and transmits a response to the necessary initial access procedure between the UE and itself. The initial access may be a random access procedure.

[0046] The wireless communication unit 110 of the embodiment may include a transmission unit that transmits information indicating a frequency band in which a second carrier for standby is set before the terminal accesses the first carrier. The first carrier may be an anchor carrier, and the second carrier may be a patching carrier. The information indicating the frequency band may be all or part of the frequency band information described later.

[0047] The wireless communication unit 110 can receive the information transmitted by the wireless communication unit 210 described later. Also, the wireless communication unit 110 can transmit the information received by the wireless communication unit 210 described later.

[0048] The frequency band information providing unit 120 provides frequency band information regarding the patching carrier to the terminal. All or part of the frequency band information of the embodiment may be understood as information indicating the frequency band. The frequency band information includes all or part of the frequency band in which the patching carrier is set (for example, 700 MHz band, 800 MHz band, 2 GHz band), the priority of each patching carrier when multiple patching carriers are set in the same area (for example, patching carrier #1 = priority 1, patching carrier #2 = priority 2, patching carrier #3 = priority 3), and the frequency band set for each area when the frequency bands of the patching carriers set in each area are different (for example, area X = 700 MHz band, area Y = 800 MHz band). Note that "area" may be read as a tracking area, a cell, or a sector, etc.

[0049] All or part of the frequency band information may be broadcast to all UEs as broadcast information, for example by SIB, or transmitted to a specific UE as an RRC message. The frequency band information providing unit 120 of the embodiment may be configured as a control unit that causes the information indicating the frequency band to be transmitted as broadcast information to multiple terminals, or as information to a specific terminal.

[0050] The control unit 130 controls each functional block that constitutes the base station 100. For example, the control unit 130 controls the transmission and reception of radio signals by the wireless communication unit 110 and the provision of frequency band information by the frequency band information provision unit 120. The control unit 130 also performs scheduling for the UE 200. Furthermore, the control unit 130 executes control signals, such as processing related to radio resource control (RRC) signaling.

[0051] The control unit 130 may control the notification information broadcast on the perch carrier to include information for accessing the anchor carrier (e.g., synchronization information). The control unit 130 may also control the notification information broadcast on the perch carrier to further include PLMN / SNPN related information. Specifically, the control unit 130 includes information for accessing the anchor carrier (e.g., synchronization information) and PLMN / SNPN related information in the SIB1 broadcast on the perch carrier.

[0052] (3.2) As shown in the terminal's functional block configuration diagram 6, the UE200 comprises a wireless communication unit 210, a frequency band information acquisition unit 220, a carrier search execution unit 230, and a control unit 240.

[0053] The wireless communication unit 210 transmits and receives wireless signals in accordance with 6G to and from the base station 100.

[0054] The wireless communication unit 210 can receive one or more broadcast information from the base station 100. The broadcast information may be MIB and / or SIB (hereinafter, MIB / SIB). The broadcast information may include an information element indicating the resource for the initial access that the UE 200 makes with the base station 100. The resource for the initial access may mean a RACH resource.

[0055] The wireless communication unit 210 can receive paging messages from the base station 100. The wireless communication unit 210 also receives downlink control information for scheduling.

[0056] The wireless communication unit 210 may receive information elements indicating the operating environment of the UE200. The information elements may indicate the data type of the downlink. Examples of downlink data types include enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), Vehicle to X (V2X), Small Data Transmission (SDT), Multicast and Broadcast Service (MBS), Multimedia Priority Service / Mission Critical Service call (MPS / MCS call), and emergency call. The information elements may be included in the paging message or in the downlink control information. Note that "information elements" may simply be called "information".

[0057] Furthermore, the wireless communication unit 210 can receive information transmitted by the wireless communication unit 110. Also, the wireless communication unit 210 can transmit information it receives.

[0058] The frequency band information acquisition unit 220 acquires frequency band information for the perch carrier. The frequency band information includes the frequency band on which the perch carrier is set (e.g., 700 MHz band, 800 MHz band, 2 GHz band), and, if multiple perch carriers are set in the same area, the priority of each perch carrier (e.g., perch carrier #1 = priority 1, perch carrier #2 = priority 2, perch carrier #3 = priority 3). In addition, the frequency band information may be set for each communication operator. For example, communication operator A (PLMN ID=a) may be set to the 800 MHz band, and communication operator B (PLMN ID=b) may be set to the 2 GHz band. If the frequency bands of the perch carriers set in each area are different, the frequency bands set for each area (e.g., area X = band 700 MHz, area Y = band 800 MHz) may also be included.

[0059] The frequency band information acquisition unit 220 in this embodiment may be configured as a receiving unit that receives information indicating the frequency band on which a second carrier, which will be on standby before accessing the first carrier, is set. Here, "receive" may be understood to include not only receiving the frequency band information via the network, but also obtaining it from a pre-stored storage unit (e.g., a SIM). In this embodiment, the frequency band information acquisition unit 220 may obtain the above-mentioned frequency band information from a SIM (Subscriber Identity Module) (not shown) installed in the UE200. The frequency band information acquisition unit 220 may also receive and acquire the frequency band information as broadcast information from the network or as an RRC message. When the frequency band information acquisition unit 220 obtains the frequency band information from the network, it may store and manage it and use it for subsequent perch carrier scans.

[0060] The carrier search execution unit 230 performs a perch carrier search in the frequency band indicated by the frequency band information acquisition unit 220, based on the frequency band information acquired by the frequency band information acquisition unit 220. In other words, the perch carrier search is omitted or not performed in frequency bands other than those indicated by the frequency band information.

[0061] The carrier search execution unit 230 of the embodiment may be configured as a control unit that performs a search for the second carrier in the frequency band indicated by the information indicating the frequency band.

[0062] The control unit 240 controls each functional block that makes up the UE200. The control unit 270 controls, for example, the transmission and reception of wireless signals by the wireless communication unit 210, the acquisition of frequency band information by the frequency band information acquisition unit 220, and the carrier search execution unit 230.

[0063] (4) Operation of wireless communication systems (4.1) Challenges In existing wireless communication systems, terminals receive communication services in the cell where they are on standby. However, in future wireless communication systems such as 6G, it is being considered to separate the cell where terminals are on standby from the cell where terminals receive communication services.

[0064] The carrier of the cell where a terminal is waiting (on standby) is often called the perch carrier, and the carrier of the cell that the terminal accesses to receive communication services is often called the anchor carrier.

[0065] With the introduction of perch carriers, it is conceivable that terminals would first select a perch carrier after power-on, before accessing the anchor carrier. However, perch carriers can be configured in only a limited number of frequency bands, and conventional search methods, which cover all frequency bands, are inefficient.

[0066] The technical challenges addressed in this disclosure are not limited to those mentioned above, and other technical challenges not mentioned here will be clearly understood by a person with ordinary skill in the art to which this disclosure pertains, based on the description herein.

[0067] (4.2) Example of Operation In this embodiment, the UE200 acquires the frequency bands on which the perch carrier is set, and performs a search for the perch carrier in the acquired frequency bands. That is, the search is omitted or not performed in frequency bands other than the acquired frequency bands. This makes it possible to exclude frequency bands on which no perch carrier is set from the search target.

[0068] (4.2.1) Operation Example 1 Figure 7 shows an example of frequency band information (part 1). This frequency band information may be pre-stored in the SIM installed in the UE200, for example.

[0069] As shown in Figure 7, the SIM stores the frequency band information of the perch carriers provided by the communication operator's network, along with the PLMN ID. Specifically, the SIM corresponds to two communication operators, A and B. Communication operator A, which has a network with PLMN ID = a, has three perch carriers #1, #2, and #3 set in the 800MHz frequency band, along with their priority. Communication operator B, which has a network with PLMN ID = b, has three perch carriers #1, #2, and #3 set in the 2GHz frequency band, along with their priority.

[0070] The following describes the operation of the UE200 for perch carrier search. For example, after power-on, the UE200 first performs perch carrier selection. Specifically, it determines the network (PLMN ID) of the communication operator to be connected to, which is pre-configured in the SIM, and obtains the frequency band on which the perch carrier of that network is set. In Figure 7, if the network of communication operator A (PLMN ID=a) is determined as the connection destination, the frequency band to be searched is determined to be the 800MHz band. Then, the perch carrier search is performed in the 800MHz frequency band.

[0071] If the search detects multiple perch carriers, the strongest perch carrier may be selected. The strongest perch carrier may be the one with the strongest received power (RSRP), or it may be the one with the best quality (RSRP, RSRQ (Reference Signal Received Quality), SINR (Signal-to-Interference-plus-noise ratio), or a combination thereof).

[0072] Furthermore, if the UE200 has memorized the information of the previously selected parch carrier, it may prioritize selecting a parch carrier from the memorized information.

[0073] Furthermore, as shown in Figure 7, if the SIM contains the perch carrier priority, the perch carrier may be selected based on the stored priority. In Figure 7, in the network of communication operator A (PLMN ID = a), there are three perch carriers #1, #2, and #3, with the priorities being Priority=1 (high priority) for perch carrier #1, Priority=2 (medium priority) for perch carrier #2, and Priority=3 (low priority) for perch carrier #3. If the scan finds two perch carriers, #1 and #3, the higher priority perch carrier #1 is selected based on the priority.

[0074] Thus, in Operation Example 1, a perch carrier search can be performed in the frequency band where the perch carrier is set, as stored in the SIM installed in the UE.

[0075] (4.2.2) Operation Example 2 Figure 8 shows an example of frequency band information (part 2). This frequency band information may be pre-stored in the SIM installed in the UE200, for example.

[0076] As shown in Figure 8, the SIM stores the perch carrier frequency bands for each area. Specifically, in Area X, three perch carriers #1, #2, and #3 are set in the 800MHz frequency band along with their priority, and in Area Y, three perch carriers #1, #2, and #3 are set in the 700MHz frequency band along with their priority.

[0077] The following describes the operation of UE200 for perch carrier searching. Assume that UE200 moves from area X to area Y. When UE200 enters area Y from area X, it is outside the coverage of the perch carrier it was accessing in area X, so it performs a perch carrier reselection.

[0078] If the UE200 determines that the current location is in area Y, it retrieves the frequency band information for area Y that is set on the SIM. This determines that the frequency band to be searched is the 700MHz band. Then, it performs a perch carrier search in the 700MHz frequency band.

[0079] If the search detects multiple perch carriers, the strongest perch carrier may be selected. The strongest perch carrier may be the one with the strongest received power (RSRP), or it may be the one with the best quality (RSRP, RSRQ, SINR, or a combination thereof).

[0080] Furthermore, if the UE200 has memorized the information of the previously selected perch carrier in an area, it may prioritize selecting a perch carrier from the memorized information.

[0081] Furthermore, as shown in Figure 8, if the SIM includes a perch carrier priority, the perch carrier may be selected based on the stored priority. In Figure 8, of the three perch carriers #1, #2, and #3, perch carrier #2 has the highest priority, so perch carrier #2 is selected.

[0082] Thus, in Operation Example 2, even when moving, a perch carrier search can be performed in the frequency band where the area-specific perch carrier is set, as stored in the SIM installed in the UE.

[0083] (4.2.3) Operation Example 3 Figure 9 shows the flow for acquiring frequency band information from the network. The base station 100 broadcasts the frequency band information as broadcast information directed to multiple UE200s, or transmits it as information directed to a specific UE200. The frequency band information may be all or part of the information shown in Figures 7 and 8.

[0084] In Figure 9, the base station 100 transmits frequency band information to the UE200 in an SIB or RRC message.

[0085] For example, after power-on, the UE200 first performs a perch carrier selection. If there is no frequency band information stored in the SIM, the UE200 searches all corresponding frequency bands and selects a perch carrier. It can then receive frequency band information in the SIB broadcast by the perch carrier. The UE200 can also receive frequency band information in the SIB or RRC message broadcast by the anchor carrier accessed to receive communication services.

[0086] Thus, when the UE200 obtains frequency band information from the network, in subsequent perch carrier re-selection searches, it performs a perch carrier search in the frequency band identified based on the obtained frequency band information.

[0087] Thus, in operation example 3, even if frequency band information is not stored in the SIM installed in the UE200, the frequency band for subsequent perch carrier reselection can be identified by obtaining frequency band information from the network.

[0088] (5) Effects and Functions As described above, according to the embodiment, the UE200 can identify the frequency band in which the perch carrier is set, so it is only necessary to perform a search for the perch carrier in the identified frequency band, which enables efficient searching for the perch carrier.

[0089] Furthermore, according to the embodiment, the UE200 can efficiently perform the initial search for a perch carrier by acquiring frequency band information stored in the SIM. In addition, by acquiring frequency band information from the network, it can efficiently perform subsequent searches for perch carriers.

[0090] Furthermore, according to the embodiment, the UE200 can flexibly adapt even if the frequency band on which the perch carrier is set differs depending on the communication operator or area.

[0091] (6) Other Embodiments Although the contents of the present invention have been described above in accordance with the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0092] In the explanation of Figure 8 above, the frequency band information shows an example where one frequency band is set for one area (Area X: 800M, Area Y: 700M). However, for example, multiple frequency bands (800MHz band, 2GHz band) may be set for one Area X, in which case a search priority between frequency bands may be set to determine which frequency band to prioritize for searching (for example, the priority of the 800MHz band may be higher than the priority of the 2GHz band). Also, when multiple frequency bands (800MHz band, 2GHz band) are set for one Area X, and multiple perch carriers are set for each frequency band, the priority of the perch carrier may be set individually within each frequency band, or the priority of the perch carrier may be set for both frequency bands together.

[0093] In this disclosure, multiple options and variations may be combined as a single option / variation.

[0094] The examples of operation described above may be combined and applied in combination, as long as no inconsistencies arise.

[0095] The block diagrams used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining software with the one or more of the above devices.

[0096] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited.

[0097] For example, the base station 100 and terminal 200 in one embodiment of the present disclosure may function as computers that process the wireless communication method of the present disclosure. Figure 10 is a diagram showing an example of the hardware configuration of the base station 100 and terminal 200 according to one embodiment of the present disclosure. The above-mentioned base station 100 and terminal 200 may be physically configured as computer devices including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0098] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the base station 100 and terminal 200 may include one or more of the devices shown in the figure, or it may be configured to omit some of the devices.

[0099] Each function in the base station 100 and terminal 200 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and storage 1003.

[0100] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, and so on.

[0101] Furthermore, the processor 1001 reads programs (program code), software modules, data, etc., from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. Furthermore, although it has been explained that the above processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from a network via a telecommunications line.

[0102] Memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. Memory 1002 may also be called a register, cache, main memory, etc. Memory 1002 can store executable programs (program code), software modules, etc., for carrying out a wireless communication method according to one embodiment of the present disclosure.

[0103] The storage 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., Compact Disc, Digital Multipurpose Disc, Blu-ray® Disc), a smart card, flash memory (e.g., a card, stick, key drive), a floppy® disk, a magnetic strip, etc. The storage 1003 may also be called an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0104] The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0105] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0106] Furthermore, each device, such as the processor 1001 and memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0107] Furthermore, the base station 100 and terminal 200 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0108] Information notification is not limited to the embodiments described herein and may be carried out by other means. For example, information notification may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or combinations thereof. RRC signaling may also be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0109] Each aspect / embodiment described herein may apply to systems utilizing Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (where x is, for example, an integer or decimal), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), W-CDMA®, GSM®, CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, and other appropriate systems, as well as at least one of the next-generation systems that are extended, modified, created, or defined based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0110] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be reordered, provided they do not contradict each other. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented.

[0111] The specific operations described in this disclosure as being performed by a base station may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal can be performed by the base station and at least one other network node (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station, it may also be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0112] Information and signals (such as data) can be output from a higher layer (or lower layer) to a lower layer (or higher layer). Input and output may occur via multiple network nodes.

[0113] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0114] The determination may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, by comparing with a predetermined value).

[0115] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0116] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0117] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0118] The information, signals, etc. described in this disclosure may be represented using any of the various different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0119] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0120] The terms “system” and “network” as used in this disclosure are interchangeable.

[0121] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0122] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0123] In this disclosure, terms such as "Base Station (BS)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0124] A base station can house one or more (e.g., three) cells (also called sectors). If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may be provided with communication services by a base station subsystem (e.g., a Remote Radio Head, RRH). The terms "cell" or "sector" refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems providing communication services in that coverage.

[0125] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0126] In this disclosure, terms such as “terminal,” “user terminal,” “Mobile Station (MS),” and “User Equipment (UE)” may be used interchangeably.

[0127] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms.

[0128] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0129] Furthermore, the term "base station" in this disclosure may be interpreted as "terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the terminal 200 may have the functions that the base station 100A or 100B has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0130] Similarly, the term "terminal" in this disclosure may be interpreted as "base station." In this case, the functions of the terminal 200 described above may be provided by the base station 100A or 100B.

[0131] Figure 11 shows an example of the configuration of vehicle 2001. As shown in Figure 11, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0132] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0133] The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user.

[0134] The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2027 installed in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an Electronic Control Unit (ECU).

[0135] Signals from various sensors 2021 to 2029 include current signals from the current sensor 2021 that senses motor current, front and rear wheel rotation speed signals obtained by the rotation speed sensor 2022, front and rear wheel air pressure signals obtained by the air pressure sensor 2023, vehicle speed signals obtained by the vehicle speed sensor 2024, acceleration signals obtained by the acceleration sensor 2025, accelerator pedal depression signals obtained by the accelerator pedal sensor 2029, brake pedal depression signals obtained by the brake pedal sensor 2026, shift lever operation signals obtained by the shift lever sensor 2027, and detection signals obtained by the object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0136] The Information Services Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including car navigation systems, audio systems, speakers, televisions, and radios, and one or more ECUs that control these devices. The Information Services Unit 2012 uses information acquired from external devices via communication modules 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001.

[0137] The Information Services Unit 2012 may include input devices that accept input from external sources (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) and output devices that output to external sources (e.g., displays, speakers, LED lamps, touch panels, etc.).

[0138] The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Unit (IMU), Inertial Navigation System (INS)), Artificial Intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also sends and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0139] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2029 provided in the vehicle 2001.

[0140] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information to and from external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station.

[0141] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input.

[0142] The communication module 2013 receives various information (traffic information, signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on the information service unit 2012 installed in the vehicle. The information service unit 2012 may also be called an output unit, which outputs information (for example, it outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013).

[0143] Furthermore, the communication module 2013 stores various information received from external devices in memory 2032, which is available to the microprocessor 2031. Based on the information stored in memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2029, etc., which are provided in the vehicle 2001.

[0144] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, “determining” may include resolving, selecting, choosing, establishing, or comparing. In other words, "judgment" and "decision" can include considering that some action has been "judged" or "decided." Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0145] The terms “connected,” “coupled,” and any variations thereof mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0146] The reference signal may also be abbreviated as RS, and may be called Pilot depending on the applicable standard.

[0147] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0148] Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0149] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0150] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0151] A wireless frame may consist of one or more frames in the time domain. Each of these frames in the time domain may be called a subframe. A subframe may further consist of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0152] Numerology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerology may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0153] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on neurology.

[0154] A slot may include multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Mini-slots may also be called sub-slots. Mini-slots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called a PDSCH (or PUSCH) mapping type B.

[0155] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0156] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1 to 13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0157] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal to allocate radio resources (such as the frequency bandwidth and transmission power available to each terminal) in TTI units. However, the definition of TTI is not limited to this.

[0158] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0159] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled.

[0160] A TTI with a time length of 1 ms may also be called a normal TTI (TTI in LTE Rel. 8-12), a long TTI, a normal subframe, a long subframe, or a slot. A TTI shorter than a normal TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini slot, a subslot, or a slot.

[0161] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0162] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0163] Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0164] One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0165] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0166] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the carrier's common reference point. The PRBs may be defined and numbered within a given BWP.

[0167] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be configured within a single carrier for a UE.

[0168] At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0169] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways.

[0170] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0171] In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different."

[0172] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way.

[0173] 10 Wireless communication system 20 Wireless access network 100 Base station 110 Wireless communication unit 120 Frequency band information provision unit 130 Control unit 200 Terminal 210 Wireless communication unit 220 Frequency band information acquisition unit 230 Carrier search execution unit 240 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Rotation speed sensor 2023, air pressure sensor 2024, vehicle speed sensor 2025, acceleration sensor 2026, brake pedal sensor 2027, shift lever sensor 2028, object detection sensor 2029, accelerator pedal sensor 2030, driver assistance system unit 2031, microprocessor 2032, memory (ROM, RAM) 2033, communication port (IO port)

Claims

1. A terminal comprising: a receiving unit that receives information indicating a frequency band in which a second carrier, which will be on standby before accessing a first carrier, is set; and a control unit that searches for the second carrier in the frequency band indicated by the information indicating the frequency band.

2. The terminal according to claim 1, wherein the receiving unit receives information indicating the frequency band via a network or obtains it from a storage unit that has been stored in advance.

3. The terminal according to claim 1, wherein the information indicating the frequency band is set according to the communication operator providing the communication service or the area.

4. A base station comprising: a transmitting unit that transmits information indicating a frequency band on which a second carrier is set to be on standby before a terminal accesses a first carrier; and a control unit that causes the frequency band information to be transmitted as broadcast information to multiple terminals or as information to a specific terminal.

5. A terminal communication method comprising the steps of: receiving information indicating a frequency band on which a second carrier that will be on standby before accessing a first carrier is set; and searching for the second carrier in the frequency band indicated by the information indicating the frequency band.

Images