Terminal, base station, and communication method

Abstract

To allow initial access to be efficiently executed in a wireless communication system.SOLUTION: A terminal includes a receiving unit that sequentially switches receiving beamforming and receives a first signal consisting only of a synchronization signal, from a base station, and a control unit that determines the receiving beamforming to be applied on the basis of the measurement results of the first signal. The receiving unit applies the determined receiving beamforming to receive a second signal consisting only of a PBCH (Physical Broadcast CHannel), from the base station. The control unit performs synchronization and cell search using the second signal, and periodically alternates between receiving the first signal, and receiving the second signal using the determined receiving beamforming.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a terminal, a base station, and a communication method in a wireless communication system.

Background Art

[0002] In NR (New Radio) (also referred to as "5G"), which is a successor system to LTE (Long Term Evolution), technologies that satisfy requirements such as a large-capacity system, high data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and power saving are being studied (for example, Non-Patent Document 1).

[0003] In NR Release 17, it is being considered to use a higher frequency band than in conventional releases (for example, Non-Patent Document 2). For example, applicable numerologies including subcarrier spacing, channel bandwidth, etc. in the frequency band from 52.6 GHz to 71 GHz, the design of the physical layer, and obstacles assumed in actual wireless communication are being studied.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In communication using a higher frequency band than the conventional millimeter wave band, propagation loss becomes greater. Therefore, for example, it is necessary to reduce the loss by using a high-density fine beam using a multi-element antenna. On the other hand, when increasing the beam density, the area that can be covered becomes narrow. Therefore, as the beam density increases, the number of candidate beams increases. Therefore, when determining the beam to be used according to the reception status while sequentially switching beams (beam sweeping) in the initial access, unacceptable overhead and delay are assumed to occur.

[0006] The present invention has been made in view of the above points, and in a wireless communication system, initial access can be efficiently performed.

Means for Solving the Problems

[0007] According to the disclosed technique, there is provided a terminal including: a receiving unit that sequentially switches reception beamforming and receives a first signal composed only of a synchronization signal from a base station; and a control unit that determines reception beamforming to be applied based on a measurement result of the first signal. The receiving unit applies the determined reception beamforming and receives a second signal composed only of a PBCH (Physical Broadcast Channel) from the base station. The control unit performs synchronization and cell search using the second signal, and periodically and alternately repeats reception of the first signal and reception of the second signal using the determined reception beamforming.

Effects of the Invention

[0008] According to the disclosed technique, in a wireless communication system, initial access can be efficiently performed.

Brief Description of the Drawings

[0009]

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are appropriately used. However, the existing technology is, for example, existing LTE, but is not limited to existing LTE. In addition, the term "LTE" used in this specification shall have a broad meaning including LTE-Advanced and subsequent systems (e.g., NR) unless otherwise specified.

[0012] In addition, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel) used in existing LTE are used. This is for convenience of description, and signals, functions, etc. similar to these may be called by other names. Also, the above terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even for signals used in NR, the "NR-" is not necessarily specified.

[0013] In addition, in the embodiments of the present invention, the duplex mode may be a TDD (Time Division Duplex) mode, an FDD (Frequency Division Duplex) mode, or another mode (e.g., Flexible Duplex, etc.).

[0014] In addition, in the embodiments of the present invention, the fact that wireless parameters or the like are "configured" may mean that predetermined values are pre-configured, or that wireless parameters notified from the base station 10 or the terminal 20 are configured.

[0015] FIG. 1 is a diagram showing a configuration example (1) of a wireless communication system according to an embodiment of the present invention. As shown in FIG. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. Although one base station 10 and one terminal 20 are shown in FIG. 1, this is an example, and there may be a plurality of each.

[0016] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of the wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols, and the frequency domain may be defined by the number of sub-carriers or the number of resource blocks. The base station 10 transmits the synchronization signal and the system information to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, by NR-PBCH and is also referred to as the notification information. The synchronization signal and the system information may be referred to as an SSB (SS / PBCH block). As shown in FIG. 1, the base station 10 transmits the control signal or data to the terminal 20 in the DL (Downlink) and receives the control signal or data from the terminal 20 in the UL (Uplink). Both the base station 10 and the terminal 20 are capable of performing beamforming for signal transmission and reception. Also, both the base station 10 and the terminal 20 are capable of applying communication by MIMO (Multiple Input Multiple Output) to the DL or UL. Also, both the base station 10 and the terminal 20 may communicate via a secondary cell (SCell: Secondary Cell) and a primary cell (PCell: Primary Cell) by CA (Carrier Aggregation). Further, the terminal 20 may communicate via the primary cell of the base station 10 and the primary secondary cell group cell (PSCell: Primary SCG Cell) of another base station 10 by DC (Dual Connectivity).

[0017] The terminal 20 is a communication device having a wireless communication function such as a smartphone, a mobile phone, a tablet, a wearable terminal, a communication module for M2M (Machine-to-Machine), etc. As shown in FIG. 1, the terminal 20 receives a control signal or data from the base station 10 in the DL and transmits a control signal or data to the base station 10 in the UL, thereby using various communication services provided by the wireless communication system. Further, the terminal 20 receives various reference signals transmitted from the base station 10 and performs measurement of the propagation path quality based on the reception result of the reference signal.

[0018] FIG. 2 is a diagram showing a configuration example (2) of the wireless communication system according to the embodiment of the present invention. The millimeter wave band can support a higher data rate than, for example, a frequency band of 6 GHz or less, while large propagation loss and blockage may occur. As shown in FIG. 3, by using a large antenna array, the link capacity can be increased. In the example shown in FIG. 3, a data rate of 100 Gbps per cell is realized for a wireless LAN router, a dongle, etc. by millimeter waves to which 3D beamforming is applied using a multi-element antenna. As an example, the millimeter wave is set to be from 10 GHz to 40 GHz, but other frequencies may also be used.

[0019] However, in the beamforming as described above, since the power is concentrated in a narrow beam, it becomes difficult to adjust the beam direction at the initial access, and beam switching is required when the terminal 20 moves.

[0020] FIG. 3 is a diagram showing an example of hybrid beamforming. As shown in FIG. 3, in hybrid beamforming, both digital beamforming and analog beamforming are applied. In the example shown in FIG. 3, the transmit-side digital beamforming is performed by a baseband precoder, and the transmit-side analog beamforming is performed by a phase shifter. Also, in the example shown in FIG. 3, the receive-side analog beamforming is performed by a phase shifter, and the transmit-side analog beamforming is performed by a baseband combiner. Hereinafter, beamforming may be referred to as a beam, and beamforming and a beam may not be distinguished from each other.

[0021] Since a plurality of RF chains and transceivers (TXRUs) are used, it is necessary to control a plurality of beams simultaneously. As the number of RF chains increases, the complexity of beam search increases exponentially.

[0022] FIG. 4 is a sequence diagram for explaining an example of initial access. In 5G-NR, initial access based on beam management as shown in FIG. 4 is executed. gNB10 sequentially switches a plurality of spatial directions to transmit a synchronization signal and system information necessary for UE20 to access the network (Beam-Sweeping transmission). UE20 continues to receive until it matches the beam direction of the transmitter (Beam-Sweeping reception) to detect the strongest beam direction. When UE20 grasps the beam to be used by gNB10 (UE individual beam selection), UE20 transmits a PRACH to gNB10. Subsequently, when UE20 and gNB10 establish communication with an optimal beam, gNB10 transmits the remaining system information necessary for connection setting to UE20. The system can switch to UE individual coverage using a narrower beam using a beam reconfiguration procedure (UE individual beamforming).

[0023] In step S1, gNB10 transmits a synchronization signal to UE20. Subsequently, gNB10 transmits the master system information for all UEs to UE20 (S2). In steps S1 and S2, the above Beam-Sweeping transmission, Beam-Sweeping reception, and UE-specific beam selection may be performed. In step S3, UE20 transmits a random access channel to gNB10. Subsequently, gNB10 transmits a random access response and system information to UE20 (S4). In step S5, gNB10 transmits data and control channels to UE20. In step S5, the above UE-specific beamforming may be applied.

[0024] For example, in the initial access of communication using millimeter waves exceeding 52.6 GHz, the complexity of beam management increases. To compensate for large propagation losses, it is necessary to use a larger antenna array. For example, by using an antenna array with more than 1000 elements, a very dense and narrow beam and a very large number of candidate beams are assumed.

[0025] Beam-Sweeping in the initial access in the millimeter wave band as described above results in unacceptable overhead and delay, and it is difficult to apply the beam management in conventional 5G-NR. Therefore, in the initial access in the millimeter wave band as described above, a method for realizing highly efficient and high-speed initial access is required.

[0026] Figure 5 is a diagram showing an example of an SSB. For initial access in 5G-NR, the UE20 executes a cell search procedure that performs beam management using an SSB (SS / PBCH block) for Beam-Sweeping. The SSB is a signal for performing beam management in the idle state. As shown in Figure 5, the time domain is composed of 4 OFDM symbols, and the frequency domain is composed of 20 PRBs. Also, as shown in Figure 5, the SSB is composed of a synchronization signal including PSS and SSS and a PBCH including at least an MIB (Master Information Block) message.

[0027] Figure 6 is a diagram showing an example of an SS burst set. The SS burst set is composed of a plurality of SSBs that support Beam-Sweeping. The SS burst set is a group of up to 64 consecutive L SSBs having different beam indexes from each other. As shown in Figure 6, one SS burst set is mapped to slots within a 5 ms window (i.e., half of a radio frame). The period T B of the SS burst set is 5, 10, 20, 40, 80, or 160 ms, and the default value is 20 ms.

[0028] As described above, the conventional SSB is composed of 4 consecutive OFDM symbols. Since the period of one beam pair in initial access corresponds to at least one SSB, Beam-Sweeping requires a great deal of time and is inefficient for hundreds of candidate beams, especially when the carrier is in a high frequency band. Also, when the transmit and receive beam pairs are not optimized, there is a lot of redundant information, consuming time and frequency resources.

[0029] The overhead is calculated by (4 × T S × L) / T B . T S is the period of 1 OFDM symbol. L is the number of SSBs included in 1 SS burst set. T B is the period of the SS burst set. The delay is T B × NSS burst set is calculated. N SS burst set is the number of SS burst sets required for Beam-Sweeping.

[0030] Table 1 shows the overhead and delay for completing Beam-Sweeping in 64*4 directions (L = 64, T B = 20 ms) for one GSCN (Global Synchronization Channel Number).

[0031]

Table 1

[0032] As shown in Table 1, when the SCS is 120 KHz, the slot length is 0.125 ms, the overhead is 11.4%, and the delay is 80 ms. When the SCS is 240 KHz, the slot length is 0.0625 ms, the overhead is 5.7%, and the delay is 80 ms. Further, assuming an increase in the number of beams, it is necessary to shorten the period required for each beam pair in Beam-Sweeping.

[0033] Therefore, in beam management when using a higher frequency band than conventional, such as in the millimeter wave band, it is necessary to enhance the beam management mechanism for initial access based on the conventional SSB (SS / PBCH block) in 5G-NR.

[0034] First, define a BSB (Beam Sweeping Block) which is a new signal for Beam-Sweeping. Each BSB is composed of a plurality of SSs in the frequency domain or time domain. Since the period of the SS is shorter than that of the SSB, the time required for beam pairing processing can be shortened. At the same time, define a new signal, eSSB (enhanced SSB). There are multiple types of eSSB, which is a signal for complementing the BSB and completing the initial access. Details of the types will be described later.

[0035] Furthermore, the cell search procedure is newly designed. The new procedure includes two stages of Beam-Sweeping that are executed alternately, and multiple modes can be set. In the high-speed BSB sweep stage, which is stage 1, gNB10 transmits the BSB by Beam-Sweeping, and UE20 can obtain the optimal beam direction. In the subsequent eSSB sweep stage, which is stage 2, gNB10 transmits the eSSB by Beam-Sweeping, and UE20 performs synchronization and cell search in the reception beam direction determined in stage 1. By repeating stages 1 and 2 several times, gNB10 and UE20 can obtain the optimal beam pair. Details of the modes will be described later.

[0036] By the above enhanced beam management, the signaling overhead and delay in initial access can be reduced.

[0037] As a basic configuration of the enhanced design, the BSB for high-speed Beam-Sweeping is composed of only the PSS or a new SS, and the eSSB is mainly composed of the MIB message. gNB10 transmits the BSB and eSSB alternately to let UE20 identify the optimal beam pair and complete the initial access more quickly.

[0038] In the new beam management during initial access, stages 1 and 2 are repeatedly alternated periodically. In stage 1, a high-speed BSB sweep is performed. gNB10 transmits the BSB with Beam-Sweeping. The beam pair is sequentially switched between gNB10 and UE20, and UE20 identifies the optimal reception beam in stage 1.

[0039] In stage 2, a high-speed eSSB sweep is performed. gNB10 transmits the eSSB by Beam-Sweeping. UE20 performs synchronization and cell search in the optimal reception beam direction determined in stage 1.

[0040] FIG. 7 is a diagram for explaining an example of beam management in an embodiment of the present invention. 1) shown in FIG. 7 is an example showing conventional beam management. 2) shown in FIG. 7 is a first example of beam management in an embodiment of the present invention, in which stage 1 and stage 2 are alternately repeated with a period of 20 ms. 3) shown in FIG. 7 is a second example of beam management in an embodiment of the present invention, in which both stage 1 and stage 2 are executed within 5 ms and repeated with a period of 20 ms.

[0041] Here, it is assumed that 1 BSB is composed of 4 beams and 1 period (default 20 ms) is composed of 64 BSBs. For example, when Nt (number of SSBs) * Nr (number of received beams) = 64 * 4 and the SCS is 120 KHz, the conventional beam management requires 80 ms to complete the Beam-Sweeping process. On the other hand, the new beam management shown in 2) of FIG. 7 can complete the Beam-Sweeping process in 40 ms. Also, the new beam management shown in 3) of FIG. 7 can complete the Beam-Sweeping process in 20 ms.

[0042] FIG. 8 is a diagram showing a configuration example (1) of a signal for beam management stage 1 in an embodiment of the present invention. Two types may be defined as BSB. Let the signal shown in FIG. 8 be BSB type 1. As shown in FIG. 8, M1 consecutive OFDM symbols include SSs in a common frequency region. The direction of the beam may be different for each OFDM symbol. Hereinafter, the number of beams per BSB is denoted as M, and the number M of beams of BSB type 1 is M1.

[0043] FIG. 9 is a diagram showing a configuration example (2) of the signal for the beam management stage 1 in the embodiment of the present invention. The signal shown in FIG. 9 is defined as BSB type 2. As shown in FIG. 9, each of the consecutive M1 OFDM symbols includes M2 SSs and CP (Cyclic Prefix) in the time domain. As shown in FIG. 9, the beam directions of each of the M2 SSs may be different. The number M of beams of BSB type 2 is M1*M2.

[0044] In the following description, unless otherwise specified, BSB corresponds to BSB type 1.

[0045] FIG. 10 is a diagram showing a configuration example (1) of the signal for the beam management stage 2 in the embodiment of the present invention. The eSSB type 1 shown in FIG. 10 is composed of consecutive 4 OFDM symbols. The eSSB type 1 has the structure of SSB for compatibility with NR. As shown in FIG. 10, PSS is arranged in OFDM symbol #0, PBCH is arranged in OFDM symbol #1, SSS and PBCH are arranged in OFDM symbol #2, and PBCH is arranged in OFDM symbol #3. The PSS constituting the BSB is only used for Beam-Sweeping.

[0046] FIG. 11 is a diagram showing a configuration example (2) of the signal for the beam management stage 2 in the embodiment of the present invention. The eSSB type 2 shown in FIG. 11 is composed of consecutive 3 OFDM symbols with PSS omitted in order to perform Beam-Sweeping at high speed. As shown in FIG. 11, PBCH is arranged in OFDM symbol #0, SSS and PBCH are arranged in OFDM symbol #1, and PBCH is arranged in OFDM symbol #2. The PCI (Physical cell identifier) is identified using the SSS included in the eSSB type 2 and the PSS constituting the BSB.

[0047] FIG. 12 is a diagram showing a configuration example (3) of signals for the beam management stage 2 in an embodiment of the present invention. The eSSB type 3 shown in FIG. 12 is composed of two consecutive OFDM symbols including only PBCH in order to achieve extremely small delay. As shown in FIG. 11, PBCH is arranged in OFDM symbol #0 and PBCH is arranged in OFDM symbol #1. The SSs constituting the BSB are used for identifying the PCI. In the PBCH of the eSSB type 3, the resources in the frequency domain may be increased.

[0048] By combining the above-described BSB type 1 and BSB type 2 with eSSB type 1, eSSB type 2, and eSSB type 3, respectively, six types of signal formats can be defined.

[0049] FIG. 13 is a diagram for explaining an example of the beam management stage 1 in an embodiment of the present invention. Hereinafter, the details of the above-described stage 1 will be described. Stage 1 is a procedure for performing high-speed beam-sweeping and realizes high-speed beam search. A group of L1 consecutive BSBs within less than 5 ms is defined as a BS burst set. In stage 1, the gNB 10 sequentially switches candidate transmission beams and transmits a plurality of BSBs. Also in stage 1, the UE 20 sequentially switches candidate reception beams and identifies an optimal reception beam based on, for example, the RSRP value.

[0050] Stage 1 may have periodicity. The period of the periodicity may be determined by the UE 20 or may be defined in advance. For example, a BSB index of log2(N2L2) bits may be modulated to the BSB by cyclic shift. L2 is the number of eSSBs included in one period of the burst set of eSSBs, and N2 is the number of times of stage 2 to be executed. Further, the UE 20 may sequentially switch all reception beams until an optimal reception beam is found.

[0051] Since only the optimal reception beam is determined in stage 1, the transmission beam in stage 1 may be coarser than the transmission beam in stage 2 in order to reduce the number of beam pairs.

[0052] In the example of stage 1 shown in FIG. 13, each of the L1 BSBs is transmitted from the gNB 10 with four transmission beams. For example, different beams may be used for the odd-numbered BSBs and the even-numbered BSBs, and eight transmission beams may be used in the BS burst set. On the other hand, the UE 20 may use all reception beams.

[0053] FIG. 14 is a diagram for explaining an example of beam management stage 2 in an embodiment of the present invention. Hereinafter, the details of stage 2 described above will be explained. Stage 2 is a procedure for performing a high-speed eSSB sweep, and synchronization and cell search are performed. In stage 2, the gNB 10 sequentially switches transmission beams to transmit eSSBs. On the other hand, in stage 2, the UE 20 fixes to the optimal reception beam determined in stage 1 and completes synchronization and cell search. Without loss of generality, a combination of BSB + eSSB type 1 (SSB similar to NR) can be assumed. Here, within N2 consecutive SS burst sets, N t is set to N2L2 so that synchronization and cell search are completed.

[0054] Since the UE 20 can identify the optimal reception beam in stage 1, in stage 2, the UE 20 can perform reception using only the optimal reception beam. Therefore, the required number of eSSBs to be transmitted does not exceed N t = N2L2.

[0055] In the example of stage 2 shown in FIG. 14, each of the L2 eSSBs is transmitted from the gNB 10 while sequentially switching the transmission beam. On the other hand, the UE 20 fixedly uses the optimal reception beam determined in stage 1 to perform synchronization and cell search. The UE 20 may report information indicating the eSSB with the best measurement result to the gNB 10 and specify the transmission beam to be applied by the gNB 10.

[0056] FIG. 15 is a diagram for explaining an example (1) of beam management transmission mode 1 in an embodiment of the present invention. The beam management in the embodiment of the present invention has three transmission modes based on the periodicity of stage 1 and stage 2 in order to cope with different scenarios and system requirements. Hereinafter, transmission mode 1 will be described. The feature of transmission mode 1 is to minimize the average delay. FIG. 15 is an example in which transmission mode 1 is applied to BSB+eSSB type 1. As shown in FIG. 15, each stage occupies a fixed number of 5 ms-long windows associated with the maximum number of beam pairs. In the example shown in FIG. 15, the number of 5 ms-long windows is 1. In stage 1, 4 transmission beams are used for each L1 BSBs, and in stage 2, 1 transmission beam is used for each L2 eSSBs.

[0057] FIG. 16 is a diagram for explaining an example (2) of beam management transmission mode 1 in an embodiment of the present invention. FIG. 16 is an example in which transmission mode 1 is applied to BSB+eSSB type 2. As shown in FIG. 16, each stage occupies a fixed number of 5 ms-long windows associated with the maximum number of beam pairs. In the example shown in FIG. 16, the number of 5 ms-long windows is 1. In stage 1, 4 transmission beams are used for each L1 BSBs, and in stage 2, 1 transmission beam is used for each L2 eSSBs.

[0058] FIG. 17 is a diagram for explaining an example (3) of beam management transmission mode 1 in an embodiment of the present invention. FIG. 17 is an example in which transmission mode 1 is applied to BSB+eSSB type 3. As shown in FIG. 17, each stage occupies a fixed number of 5 ms-long windows associated with the maximum number of beam pairs. In the example shown in FIG. 17, the number of 5 ms-long windows is 1. In stage 1, 4 transmission beams are used for each L1 BSBs, and in stage 2, 1 transmission beam is used for each L2 eSSBs.

[0059] FIG. 18 is a diagram for explaining an example (1) of the beam management transmission mode 2 in the embodiment of the present invention. Hereinafter, the transmission mode 2 will be described. The feature of the transmission mode 2 is to more appropriately support the change of the number of beam pairs. FIG. 18 is an example in which the transmission mode 2 is applied to the BSB+eSSB type 1. As shown in FIG. 18, each stage occupies a single 5 ms half-frame, and stages 1 and 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0060] FIG. 19 is a diagram for explaining an example (2) of the beam management transmission mode 2 in the embodiment of the present invention. FIG. 19 is an example in which the transmission mode 2 is applied to the BSB+eSSB type 2. As shown in FIG. 19, each stage occupies a single 5 ms half-frame, and stages 1 and 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0061] FIG. 20 is a diagram for explaining an example (3) of the beam management transmission mode 2 in the embodiment of the present invention. FIG. 20 is an example in which the transmission mode 2 is applied to the BSB+eSSB type 3. As shown in FIG. 20, each stage occupies a single 5 ms half-frame, and stages 1 and 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0062] FIG. 21 is a diagram for explaining an example (1) of beam management transmission mode 3 in an embodiment of the present invention. Hereinafter, transmission mode 3 will be described. The feature of transmission mode 3 is an integrated frame structure. FIG. 21 is an example in which transmission mode 3 is applied to BSB+eSSB type 1. As shown in FIG. 21, stage 1 and stage 2 are integrated and arranged within a single 5 ms half-frame, and stage 1 and stage 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0063] FIG. 22 is a diagram for explaining an example (2) of beam management transmission mode 3 in an embodiment of the present invention. FIG. 22 is an example in which transmission mode 3 is applied to BSB+eSSB type 2. As shown in FIG. 22, stage 1 and stage 2 are integrated and arranged within a single 5 ms half-frame, and stage 1 and stage 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0064] FIG. 23 is a diagram for explaining an example (3) of beam management transmission mode 3 in an embodiment of the present invention. FIG. 23 is an example in which transmission mode 3 is applied to BSB+eSSB type 3. As shown in FIG. 23, stage 1 and stage 2 are integrated and arranged within a single 5 ms half-frame, and stage 1 and stage 2 may be repeated. In stage 1, four transmission beams are used for each L1 BSBs, and in stage 2, one transmission beam is used for each L2 eSSBs.

[0065] FIG. 24 is a diagram for explaining an example (1) of mapping of signals for the beam management stage 1 in the embodiment of the present invention. Hereinafter, a method of mapping the BSB to physical resources for each case where SCS and M1 are different will be described. FIG. 24 shows an example of the BSB where SCS is 120 KHz, M1 = 4, and L1 = 64. As shown in FIG. 24, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged in each slot. The index of the symbol at which the arrangement of the BSB starts is {2, 8}+14n. For the carrier frequency included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 20, 21, 22, 23, 24, 25, 26, 27, 30, 31, 32, 33, 34, 35, 36, 37}. As shown in FIG. 24, in the first 10 slots in a 5 ms half-frame, the BSB is arranged in all slots from slot 0 to slot 7. Within a slot, the indices of the symbols in which the BSB is arranged are 2, 3, 4, 5, 8, 9, 10, 11. Although FIG. 24 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0066] FIG. 25 is a diagram for explaining an example (2) of mapping of signals for the beam management stage 1 in the embodiment of the present invention. FIG. 25 shows an example of a BSB where the SCS is 240 KHz, M1 = 4, and L1 = 64. As shown in FIG. 25, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged in each slot. The index of the symbol at which the arrangement of the BSB starts is {4, 8, 16, 20}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17}. As shown in FIG. 25, in the first 20 slots of the first 1 / 4 frame of 2.5 ms, the BSB is arranged in all slots from slot 0 to slot 15. Within a slot, the indexes of the symbols in the first slot where the BSB is arranged are 4, 5, 6, 7, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 6, 7, 8, 9. Although FIG. 25 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0067] FIG. 26 is a diagram for explaining an example (3) of the mapping of the signal for the beam management stage 1 in the embodiment of the present invention. FIG. 26 shows an example of a BSB where the SCS is 120 KHz, M1 = 8, and L1 = 32. As shown in FIG. 26, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged in each slot. The index of the symbol at which the arrangement of the BSB starts is {4, 16}+28n. For the carrier frequency included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18}. As shown in FIG. 26, in the first 10 slots of the 5 ms half-frame, the BSB is arranged in all slots from slot 0 to slot 7. Within a slot, the indexes of the symbols in the first slot where the BSB is arranged are 4, 5, 6, 7, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 6, 7, 8, 9. Note that although FIG. 26 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0068] FIG. 27 is a diagram for explaining an example (4) of mapping of signals for the beam management stage 1 in the embodiment of the present invention. FIG. 27 shows an example of a BSB where SCS is 240 KHz, M1 = 8, and L1 = 32. As shown in FIG. 27, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged every 2 slots. The index of the symbol at which the arrangement of the BSB starts is {8, 16, 32, 40}+56n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8}. As shown in FIG. 27, in the first 20 slots of the first 1 / 4 frame of 2.5 ms, the BSB is arranged in all slots from slot 0 to slot 15. Within a slot, the indexes of the symbols in the first slot where the BSB is arranged are 8, 9, 10, 11, 12, 13, the indexes of the symbols in the second slot are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, the indexes of the symbols in the third slot are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and the indexes of the symbols in the fourth slot are 0, 1, 2, 3, 4, 5. Although FIG. 27 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0069] FIG. 28 is a diagram for explaining an example (5) of mapping of signals for the beam management stage 1 in an embodiment of the present invention. FIG. 28 shows an example of a BSB where the SCS is 120 KHz, M1 = 10, and L1 = 32. As shown in FIG. 28, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged in each slot. The index of the symbol at which the arrangement of the BSB starts is {2}+14n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 20, 21, 22, 23, 24, 25, 26, 27, 30, 31, 32, 33, 34, 35, 36, 37}. As shown in FIG. 28, in the first 10 slots in a 5 ms half-frame, the BSB is arranged in all slots from slot 0 to slot 7. Within a slot, the indexes of the symbols at which the BSB is arranged are 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Although FIG. 28 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0070] FIG. 29 is a diagram for explaining an example (6) of mapping of signals for the beam management stage 1 in the embodiment of the present invention. FIG. 29 shows an example of a BSB where SCS is 240 KHz, M1 = 10, and L1 = 32. As shown in FIG. 29, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged every 2 slots. The index of the symbol at which the arrangement of the BSB starts is {4, 14}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17}. As shown in FIG. 29, in the first 20 slots of the first 1 / 4 frame of 2.5 ms, the BSB is arranged in all slots from slot 0 to slot 15. Within a slot, the indexes of the symbols in the first slot where the BSB is arranged are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and the indexes of the symbols in the second slot are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Although FIG. 27 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0071] FIG. 30 is a diagram for explaining an example (7) of the mapping of signals for the beam management stage 1 in the embodiment of the present invention. In a larger SCS used in the high frequency band, for example, at 480 KHz or 960 KHz, it is assumed that the period required for beam switching cannot be ignored. Therefore, for example, when the SCS is 480 KHz, the frame structure of the BSB as shown in FIG. 30 may be used. As shown in FIG. 30, it is guaranteed that the transmission resources for PDCCH or PUCCH are arranged every 2 slots. The index of the symbol at which the arrangement of the BSB starts is {2, 15}+28n. For the carrier frequencies included in FR2, n={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17} for every 1.25 ms interval. As shown in FIG. 30, in the first 40 slots of the 5 ms half frame, the BSB is arranged in all slots from slot 0 to slot 35. Within a slot, the indexes of the symbols in the first slot where the BSB is arranged are 2, 4, 6, 8, 10, 12, and the indexes of the symbols in the second slot are 1, 3, 5, 7, 9, 11. That is, at least one symbol's worth of time required for beam switching is ensured. Note that although FIG. 30 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0072] FIG. 31 is a diagram for explaining an example (1) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. Hereinafter, a method of mapping eSSB to physical resources for each case where the SCS is different will be described. FIG. 31 shows an example of eSSB type 1 where the SCS is 120 KHz and L2 = 64. The index of the symbol at which the arrangement of eSSB type 1 starts is {4, 8, 16, 20}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18}. As shown in FIG. 31, in the first 10 slots in a 5 ms half-frame, eSSB type 1 is arranged in all slots from slot 0 to slot 7. Within a slot, the indexes of the symbols in the first slot where eSSB type 1 is arranged are 4, 5, 6, 7, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 6, 7, 8, 9. Note that although FIG. 31 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0073] FIG. 32 is a diagram for explaining an example (2) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. FIG. 32 shows an example of eSSB type 1 where the SCS is 240 KHz and L2 = 64. The index of the symbol at which the placement of eSSB type 1 starts is {8, 12, 16, 20, 32, 36, 40, 44}+56n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8}. As shown in FIG. 32, in the first 20 slots in the first 1 / 4 frame of 2.5 ms, eSSB type 1 is placed in all slots from slot 0 to slot 15. Within a slot, the indexes of the symbols in the first slot where eSSB type 1 is placed are 8, 9, 10, 11, 12, 13, the indexes of the symbols in the second slot are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, the indexes of the symbols in the third slot are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and the indexes of the symbols in the fourth slot are 0, 1, 2, 3, 4, 5. Note that although FIG. 32 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0074] FIG. 33 is a diagram for explaining an example (3) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. In a larger SCS used in the high frequency band, for example, at 480 KHz or 960 KHz, it is assumed that the period required for beam switching cannot be ignored. Therefore, for example, when the SCS is 480 KHz, an eSSB type 1 frame structure as shown in FIG. 33 may be used. The index of the symbol at which the arrangement of eSSB type 1 starts is {3, 8, 16, 21}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17} for each 1.25 ms interval. As shown in FIG. 33, in the first 40 slots of the 5 ms half-frame, eSSB type 1 is arranged in all slots from slot 0 to slot 35. Within a slot, the indexes of the symbols in the first slot where eSSB type 1 is arranged are 3, 4, 5, 6, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 7, 8, 9, 10. That is, at least the time required for beam switching is secured for one symbol. Although FIG. 33 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0075] FIG. 34 is a diagram for explaining an example (4) of the mapping of the signal for the beam management stage 2 in the embodiment of the present invention. FIG. 34 shows an example of eSSB type 2 where the SCS is 120 KHz and L2 = 64. The index of the symbol at which the arrangement of eSSB type 2 starts is {3, 6, 9, 16, 19, 22}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18}. As shown in FIG. 34, in the first 10 slots in a 5 ms half-frame, eSSB type 2 is arranged in all slots from slot 0 to slot 7. Within a slot, the indexes of the symbols in the first slot where eSSB type 2 is arranged are 3, 4, 5, 6, 7, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 6, 7, 8, 9, 10. Note that although FIG. 34 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0076] FIG. 35 is a diagram for explaining an example (5) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. FIG. 35 shows an example of eSSB type 2 where SCS is 240 KHz and L2 = 64. The index of the symbol at which the arrangement of eSSB type 2 starts is {6, 9, 12, 15, 18, 21, 32, 35, 38, 41, 44, 47}+56n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8}. As shown in FIG. 35, in the first 20 slots of the first 1 / 4 frame of 2.5 ms, eSSB type 2 is arranged in all slots from slot 0 to slot 15. Within a slot, the indexes of the symbols in the first slot where eSSB type 2 is arranged are 6, 7, 8, 9, 10, 11, 12, 13, the indexes of the symbols in the second slot are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, the indexes of the symbols in the third slot are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and the indexes of the symbols in the fourth slot are 0, 1, 2, 3, 4, 5, 6, 7. Note that although FIG. 35 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0077] FIG. 36 is a diagram for explaining an example (6) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. In a larger SCS used in the high frequency band, for example, at 480 KHz or 960 KHz, it is assumed that the period required for beam switching cannot be ignored. Therefore, for example, when the SCS is 480 KHz, an eSSB type 2 frame structure as shown in FIG. 36 may be used. The index of the symbol at which the arrangement of eSSB type 2 starts is {2, 6, 10, 15, 19, 23}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17} for each 1.25 ms interval. As shown in FIG. 36, in the first 40 slots of the 5 ms half frame, eSSB type 2 is arranged in all slots from slot 0 to slot 35. Within a slot, the indexes of the symbols in the first slot where eSSB type 2 is arranged are 2, 3, 4, 6, 7, 8, 10, 11, 12, and the indexes of the symbols in the second slot are 1, 2, 3, 5, 6, 7, 9, 10, 11. That is, at least the time required for beam switching is ensured for one symbol. Note that although FIG. 36 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0078] FIG. 37 is a diagram for explaining an example (7) of mapping of signals for the beam management stage 2 in the embodiment of the present invention. FIG. 37 shows an example of eSSB type 3 where SCS is 120 KHz and L2 = 64. The index of the symbol at which the arrangement of eSSB type 3 starts is {4, 6, 8, 10, 16, 18, 20, 22}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18}. As shown in FIG. 34, in the first 10 slots of a 5 ms half-frame, eSSB type 3 is arranged in all slots from slot 0 to slot 7. Within a slot, the indexes of the symbols in the first slot where eSSB type 3 is arranged are 4, 5, 6, 7, 8, 9, 10, 11, and the indexes of the symbols in the second slot are 2, 3, 4, 5, 6, 7, 8, 9. Note that although FIG. 37 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0079] FIG. 38 is a diagram for explaining an example (8) of the mapping of signals for the beam management stage 2 in the embodiment of the present invention. FIG. 38 shows an example of eSSB type 3 where SCS is 240 KHz and L2 = 64. The index of the symbol at which the placement of eSSB type 3 starts is {8, 10, 12, 14, 16, 18, 20, 22, 32, 34, 36, 38, 40, 42, 44, 46}+56n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 5, 6, 7, 8}. As shown in FIG. 38, in the first 20 slots of the first 1 / 4 frame of 2.5 ms, eSSB type 3 is placed in all slots from slot 0 to slot 15. Within a slot, the indices of the symbols in the first slot where eSSB type 3 is placed are 8, 9, 10, 11, 12, 13, the indices of the symbols in the second slot are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, the indices of the symbols in the third slot are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and the indices of the symbols in the fourth slot are 0, 1, 2, 3, 4, 5. Note that although FIG. 38 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0080] FIG. 39 is a diagram for explaining an example (9) of mapping of signals for the beam management stage 2 in the embodiment of the present invention. In a larger SCS used in the high frequency band, for example, at 480 KHz or 960 KHz, it is assumed that the period required for beam switching cannot be ignored. Therefore, for example, when the SCS is 480 KHz, an eSSB type 3 frame structure as shown in FIG. 39 may be used. The index of the symbol at which the arrangement of eSSB type 3 starts is {2, 5, 8, 11, 15, 18, 21, 24}+28n. For the carrier frequencies included in FR2, n = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17} for each 1.25 ms interval. As shown in FIG. 39, in the first 40 slots of the 5 ms half frame, eSSB type 3 is arranged in all slots from slot 0 to slot 35. Within a slot, the indexes of the symbols in the first slot where eSSB type 3 is arranged are 2, 3, 5, 6, 8, 9, 11, 12, and the indexes of the symbols in the second slot are 1, 2, 4, 5, 7, 8, 10, 11. That is, at least the time required for beam switching is ensured for one symbol. Although FIG. 39 shows transmission mode 1, generality is not lost and it can also be applied to other transmission modes.

[0081] According to the above-described embodiments, the base station 10 and the terminal 20 can reduce the overhead and delay related to initial access by performing beam management that enables high-speed Beam-Sweeping.

[0082] That is, in the wireless communication system, initial access can be efficiently executed.

[0083] (Device Configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described so far will be described. The base station 10 and the terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and the terminal 20 may each be provided with only some of the functions in the embodiments.

[0084] <Base Station 10> FIG. 40 is a diagram showing an example of the functional configuration of the base station 10 in the embodiment of the present invention. As shown in FIG. 40, the base station 10 includes a transmission unit 110, a reception unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in FIG. 40 is merely an example. As long as the operations according to the embodiment of the present invention can be executed, the functional classification and the names of the functional units can be anything.

[0085] The transmission unit 110 includes a function of generating a signal to be transmitted to the terminal 20 side and wirelessly transmitting the signal. Further, the transmission unit 110 transmits an inter-network node message to another network node. The reception unit 120 includes a function of receiving various signals transmitted from the terminal 20 and obtaining information of a higher layer, for example, from the received signals. Further, the transmission unit 110 has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, etc. to the terminal 20. Further, the reception unit 120 receives an inter-network node message from another network node.

[0086] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20. The content of the setting information is, for example, information related to the setting of initial access.

[0087] As described in the embodiments, the control unit 140 performs control related to the setting of initial access. Further, the control unit 140 controls transmission beamforming. The functional unit related to signal transmission in the control unit 140 may be included in the transmission unit 110, and the functional unit related to signal reception in the control unit 140 may be included in the reception unit 120.

[0088] <Terminal 20> FIG. 41 is a diagram showing an example of the functional configuration of the terminal 20 in the embodiment of the present invention. As shown in FIG. 41, the terminal 20 includes a transmission unit 210, a reception unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in FIG. 41 is merely an example. As long as the operations according to the embodiment of the present invention can be executed, the functional classification and the names of the functional units may be any.

[0089] The transmission unit 210 creates a transmission signal from the transmission data and wirelessly transmits the transmission signal. The reception unit 220 wirelessly receives various signals and acquires signals of a higher layer from the received physical layer signals. Further, the reception unit 220 has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, etc. transmitted from the base station 10. Further, for example, the transmission unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. to other terminals 20 as D2D communication, and the reception unit 220 receives PSCCH, PSSCH, PSDCH, or PSBCH, etc. from other terminals 20.

[0090] The setting unit 230 stores various setting information received from the base station 10 by the reception unit 220. Further, the setting unit 230 also stores preset setting information. The content of the setting information is, for example, information related to the initial access setting.

[0091] The control unit 240 performs control related to the initial access setting as described in the embodiment. Further, the control unit 240 controls reception beamforming. The functional unit related to signal transmission in the control unit 240 may be included in the transmission unit 210, and the functional unit related to signal reception in the control unit 240 may be included in the reception unit 220.

[0092] (Hardware Configuration) The block diagrams (Figs. 40 and 41) used in the description of the above embodiments show blocks of functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Also, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one physically or logically combined device, or two or more physically or logically separated devices may be directly or indirectly (e.g., using wired, wireless, etc.) connected and realized using these multiple devices. The functional block may be realized by combining software with the above one device or the above multiple devices.

[0093] Functions include, but are not limited to, judgment, decision, determination, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, selection determination, establishment, comparison, assumption, expectation, regarded as, notification (broadcasting), notification (notifying), communication (communicating), forwarding, configuration (configuring), reconfiguration (reconfiguring), allocation (allocating, mapping), assignment (assigning), etc. For example, a functional block (component) that functions to transmit is referred to as a transmitting unit or a transmitter. In any case, as described above, the realization method is not particularly limited.

[0094] For example, the base station 10, the terminal 20, etc. in an embodiment of the present disclosure may function as a computer that performs the processing of the wireless communication method of the present disclosure. Fig. 42 is a diagram showing an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The above base station 10 and terminal 20 may physically be configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0095] In the following description, the term "device" can be read as a circuit, device, unit, etc. The hardware configurations of the base station 10 and the terminal 20 may be configured to include one or more of each device shown in the figure, or may be configured without including some of the devices.

[0096] Each function in the base station 10 and the terminal 20 is realized by causing a processor 1001 to perform operations and control communication by a communication device 1004, or by controlling at least one of reading and writing of data in a storage device 1002 and an auxiliary storage device 1003, by loading a predetermined software (program) onto hardware such as the processor 1001 and the storage device 1002.

[0097] The processor 1001 controls the entire computer by operating an operating system, for example. The processor 1001 may be composed of a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, etc. For example, the above-described control units 140, 240, etc. may be realized by the processor 1001.

[0098] Also, the processor 1001 reads a program (program code), software module, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes according to these. As the program, a program for causing a computer to execute at least a part of the operations described in the above embodiments is used. For example, the control unit 140 of the base station 10 shown in FIG. 40 may be stored in the storage device 1002 and realized by a control program operating on the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in FIG. 41 may be stored in the storage device 1002 and realized by a control program operating on the processor 1001. Although it has been described that the above various 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. Note that the program may be transmitted from a network via a telecommunication line.

[0099] The storage device 1002 is a computer-readable recording medium, and may be constituted by at least one of, for example, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), a RAM (Random Access Memory), etc. The storage device 1002 may be referred to as a register, a cache, a main memory (main storage device), etc. The storage device 1002 can store a program (program code), a software module, etc. executable for implementing the communication method according to an embodiment of the present disclosure.

[0100] The auxiliary storage device 1003 is a computer-readable recording medium, and may be constituted by at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (for example, a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (for example, a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-described storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the storage device 1002 and the auxiliary storage device 1003.

[0101] The communication device 1004 is hardware (a transmission / reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. in order to realize at least one of frequency-division duplexing (FDD: Frequency Division Duplex) and time-division duplexing (TDD: Time Division Duplex). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission line interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be physically or logically separated into a transmission unit and a reception unit.

[0102] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives an external input. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs an output to the outside. Note that the input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

[0103] Also, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses for each device.

[0104] Also, the base station 10 and the terminal 20 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 the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0105] (Summary of Embodiment) As described above, according to the embodiment of the present invention, a terminal is provided that includes a receiving unit that sequentially switches reception beamforming and receives a first signal composed only of a synchronization signal from a base station, and a control unit that determines reception beamforming to be applied based on a measurement result of the first signal. The receiving unit applies the determined reception beamforming and receives a second signal composed only of a physical broadcast channel (PBCH) from the base station. The control unit performs synchronization and cell search using the second signal, and periodically and alternately repeats reception of the first signal and reception of the second signal using the determined reception beamforming.

[0106] With the above configuration, the base station 10 and the terminal 20 can reduce the overhead and delay related to initial access by performing beam management that enables high-speed beam sweeping. That is, in a wireless communication system, initial access can be efficiently executed.

[0107] The first signal may be composed of only a synchronization signal. With this configuration, the terminal 20 can execute beam management that enables high-speed beam-sweeping.

[0108] Transmission beamforming different for each symbol may be applied to the first signal. With this configuration, the terminal 20 can execute beam management that enables high-speed beam-sweeping.

[0109] The second signal may be composed of only a PBCH (Physical Broadcast Channel). With this configuration, the terminal 20 can execute beam management that enables high-speed beam-sweeping.

[0110] Further, according to an embodiment of the present invention, a transmission unit that transmits a first signal composed of only a synchronization signal to a terminal by applying transmission beamforming different for each symbol, sequentially switches the transmission beamforming, and transmits a second signal composed of only a PBCH to the terminal; a reception unit that receives information indicating a measurement result of the second signal from the terminal; and a control unit that determines transmission beamforming to be applied based on the information indicating the measurement result, are provided, and the transmission of the first signal and the transmission of the second signal using the determined transmission beamforming are repeatedly alternated periodically. A base station is provided.

[0111] With the above configuration, the base station 10 and the terminal 20 can reduce the overhead and delay related to initial access by executing beam management that enables high-speed beam-sweeping. That is, in a wireless communication system, initial access can be executed efficiently.

[0112] Also, according to an embodiment of the present invention, there is provided a communication method executed by a terminal, comprising: sequentially switching reception beamforming to receive a first signal composed only of a synchronization signal from a base station; determining reception beamforming to be applied based on a measurement result of the first signal; applying the determined reception beamforming to receive a second signal composed only of a PBCH (Physical Broadcast Channel) from the base station; and performing synchronization and cell search using the second signal, and periodically and alternately repeating reception of the first signal and reception of the second signal using the determined reception beamforming.

[0113] With the above configuration, the base station 10 and the terminal 20 can reduce the overhead and delay related to initial access by executing beam management that enables high-speed Beam-Sweeping. That is, in a wireless communication system, initial access can be efficiently executed.

[0114] (Supplement of the embodiment) The embodiments of the present invention have been described above. However, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, etc. Although specific numerical examples have been used for the purpose of facilitating the understanding of the invention, unless otherwise specified, those numerical values are merely examples and any appropriate values may be used. The classification of the items in the above description is not essential to the present invention, and the matters described in two or more items may be used in combination as needed, or the matters described in one item may be applied to the matters described in another item (as long as there is no contradiction). The boundaries of the functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical components. The operations of a plurality of functional units may be physically performed by one component, or the operation of one functional unit may be physically performed by a plurality of components. Regarding the processing procedures described in the embodiments, the order of processing may be changed as long as there is no contradiction. For the sake of convenience in explaining the processing, the base station 10 and the terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software that operates by the processor included in the base station 10 according to the embodiment of the present invention and the software that operates by the processor included in the terminal 20 according to the embodiment of the present invention may be stored in a random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk drive (HDD), removable disk, CD-ROM, database, server, or any other appropriate storage medium, respectively.

[0115] Furthermore, the notification of information is not limited to the aspects / embodiments described in this disclosure, and other methods may be used. For example, the notification of information may be implemented by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, notification information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. Also, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup (RRC Connection Setup) message, an RRC connection reconfiguration (RRC Connection Reconfiguration) message, etc.

[0116] Each aspect / embodiment described in this disclosure may be applied to at least one of a system using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), other suitable systems, and next-generation systems extended based thereon. Also, a plurality of systems may be combined (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) and applied.

[0117] The processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this specification may be reordered as long as there is no contradiction. For example, regarding the methods described in this disclosure, the elements of various steps are presented using an exemplary order and are not limited to the specific order presented.

[0118] The specific operations assumed to be performed by the base station 10 in this specification may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 can be performed by at least one of the base station 10 and other network nodes other than the base station 10 (for example, but not limited to, an MME or an S-GW, etc.). Although the case where there is one other network node other than the base station 10 is exemplified above, the other network node may be a combination of a plurality of other network nodes (for example, an MME and an S-GW).

[0119] The information or signals, etc. described in this disclosure can be output from an upper layer (or a lower layer) to a lower layer (or an upper layer). They may also be input and output via a plurality of network nodes.

[0120] The input and output information, etc. may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information, etc. can be overwritten, updated, or appended. The output information, etc. may be deleted. The input information, etc. may be transmitted to other devices.

[0121] The determination in this disclosure may be made by a value represented by 1 bit (0 or 1), or by a Boolean value (true or false), or by a numerical comparison (for example, comparison with a predetermined value).

[0122] Software should be broadly construed 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, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or by any other name.

[0123] Also, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, when software is transmitted from a website, server, or other remote source using at least one of wired technologies (such as coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technologies (such as infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of the transmission medium.

[0124] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc., which 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.

[0125] Note that terms described 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 a channel and a symbol may be a signal (signaling). Also, a signal may be a message. Also, a component carrier (CC) may be referred to as a carrier frequency, cell, frequency carrier, etc.

[0126] The terms "system" and "network" used in this disclosure are used interchangeably.

[0127] Also, the information, parameters, etc. described in the present disclosure may be represented using absolute values, relative values from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0128] The names used for the above-described parameters are not limiting names in any respect. Furthermore, mathematical formulas, etc. using these parameters may be different from those explicitly disclosed in the present disclosure. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, the various names assigned to these various channels and information elements are not limiting names in any respect.

[0129] In the present disclosure, terms such as "base station (BS: Base Station)", "radio base station", "base station device", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier", etc. may be used interchangeably. The base station may also be called by terms such as macrocell, small cell, femtocell, picocell, etc.

[0130] A base station can accommodate one or more (e.g., three) cells. When the base station accommodates a plurality of cells, the entire coverage area of the base station can be divided into a plurality of smaller areas, and each of the smaller areas can also provide communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to part or all of the coverage area of at least one of the base station and the base station subsystem that provides communication services in this coverage.

[0131] In the present disclosure, terms such as "mobile station (MS)", "user terminal", "user equipment (UE)", and "terminal" can be used interchangeably.

[0132] 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 some other appropriate term.

[0133] At least one of the base station and the mobile station may also be called a transmission device, a reception device, a communication device, etc. Note that at least one of the base station and the mobile station may also be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), a moving body that moves without a driver (e.g., a drone, an autonomous vehicle, etc.), or a robot (humanoid or non-humanoid). Note that at least one of the base station and the mobile station also includes a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0134] In addition, the base station in the present disclosure may be replaced by a user terminal. For example, for a configuration in which communication between the base station and the user terminal is replaced with communication between a plurality of terminals 20 (which may be referred to as, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.), each aspect / embodiment of the present disclosure may be applied. In this case, the functions of the above-described base station 10 may be configured to be functions of the terminal 20. Also, terms such as "uplink" and "downlink" may be replaced with terms corresponding to inter-terminal communication (for example, "side"). For example, the uplink channel, downlink channel, etc. may be replaced with side channels.

[0135] Similarly, the user terminal in the present disclosure may be replaced by a base station. In this case, the functions of the above-described user terminal may be configured to be functions of the base station.

[0136] The terms "determining" and "deciding" as used in this disclosure may encompass a wide variety of operations. "Determining" and "deciding" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up (e.g., searching in a table, database, or another data structure), ascertaining, and considering something as having been "determined" or "decided". Also, "determining" and "deciding" may include considering something as having been "determined" or "decided" after receiving (e.g., receiving information), transmitting (e.g., transmitting information), inputting, outputting, accessing (e.g., accessing data in a memory), etc. Further, "determining" and "deciding" may include considering something as having been "determined" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. That is, "determining" and "deciding" may include considering something as having been "determined" or "decided" after performing some operation. Also, "determining (deciding)" may be read as "assuming", "expecting", "considering", etc.

[0137] The terms "connected" or "coupled", or any variations thereof, mean any direct or indirect connection or coupling between two or more elements, and can include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements can be physical, logical, or a combination thereof. For example, "connected" may be read as "accessed". As used in this disclosure, two elements can be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, and also, by way of some non-limiting and non-exhaustive examples, electromagnetic energy having wavelengths in the radio frequency region, microwave region, and optical (both visible and invisible) region, etc.

[0138] The reference signal can also be abbreviated as RS (Reference Signal) and may be called a Pilot depending on the applicable standard.

[0139] As used in this disclosure, the description "based on" does not mean "based only on" unless otherwise specified. In other words, the description "based on" means both "based only on" and "based at least on".

[0140] Any reference to an element using designations such as "first", "second", etc. used in this disclosure does not generally limit the quantity or order of those elements. These designations can be used in this disclosure as a convenient way to distinguish between two or more elements. Thus, a reference to a first and a second element does not mean that only two elements can be employed, or that the first element must precede the second element in any form.

[0141] In the configuration of each of the above devices, "means" may be replaced with "section", "circuit", "device", etc.

[0142] In the present disclosure, when the terms "include", "including" and their variants are used, these terms are intended to be inclusive, similar to the term "comprising". Further, the term "or" used in the present disclosure is not intended to be an exclusive disjunction.

[0143] A wireless frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. The subframe may have a fixed time length (e.g., 1 ms) that does not depend on numerology.

[0144] Numerology may be communication parameters applied to at least one of transmission and reception of a certain signal or channel. Numerology may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, wireless frame configuration, specific filtering processing performed by a transceiver in the frequency domain, specific windowing processing performed by a transceiver in the time domain, etc.

[0145] A slot may be composed of one or more symbols (such as OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.) in the time domain. A slot may be a time unit based on numerology.

[0146] A slot may include a plurality of mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. Also, a mini-slot may be called a sub-slot. A mini-slot may be composed of a smaller number of 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.

[0147] A radio frame, a sub-frame, a slot, a mini-slot, and a symbol all represent time units when transmitting a signal. Different names corresponding to each of them may also be used.

[0148] For example, one sub-frame may be called a Transmission Time Interval (TTI), or a plurality of consecutive sub-frames may be called a TTI, or one slot or one mini-slot may be called a TTI. That is, at least one of the sub-frame and the TTI may be a sub-frame (1 ms) in the existing LTE, or a period shorter than 1 ms (for example, 1 - 13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, a mini-slot, etc. instead of a sub-frame.

[0149] Here, the TTI refers to, for example, the minimum time unit of scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as the frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in units of TTI. Note that the definition of the TTI is not limited to this.

[0150] The TTI may be a transmission time unit such as a channel-coded data packet (transport block), code block, codeword, etc., or may be a processing unit such as scheduling and link adaptation. When the TTI is given, the time interval (e.g., number of symbols) in which a transport block, code block, codeword, etc. are actually mapped may be shorter than the TTI.

[0151] Note that when one slot or one mini-slot is called a TTI, one or more TTIs (i.e., one or more slots or one or more mini-slots) may be the minimum time unit for scheduling. Also, the number of slots (number of mini-slots) constituting the minimum time unit for the scheduling may be controlled.

[0152] A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel.8-12), normal TTI, long TTI, normal subframe, normal subframe, long subframe, slot, etc. A TTI shorter than the normal TTI may be called a shortened TTI, short TTI, partial TTI (partial or fractional TTI), shortened subframe, short subframe, mini-slot, sub-slot, slot, etc.

[0153] Note that the long TTI (e.g., normal TTI, subframe, etc.) may be read as a TTI having a time length exceeding 1 ms, or the short TTI (e.g., shortened TTI, etc.) may be read as a TTI having a TTI length less than that of the long TTI and equal to or more than 1 ms.

[0154] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and in the frequency domain, it may include one or a plurality of consecutive subcarriers. The number of subcarriers included in the RB may be the same regardless of the numerology, for example, it may be 12. The number of subcarriers included in the RB may be determined based on the numerology.

[0155] Also, the time domain of the RB may include one or more symbols, and may have the length of 1 slot, 1 mini-slot, 1 sub-frame, or 1 TTI. 1 TTI, 1 sub-frame, etc. may each be composed of one or more resource blocks.

[0156] Note that one or more RBs may be referred to as physical resource blocks (PRBs), sub-carrier groups (SCGs), resource element groups (REGs), PRB pairs, RB pairs, etc.

[0157] Also, the resource block may be composed of one or more resource elements (REs). For example, 1 RE may be a radio resource area of 1 sub-carrier and 1 symbol.

[0158] The bandwidth part (BWP) (which may also be called partial bandwidth, etc.) may represent a subset of consecutive common resource blocks for a certain numerology in a certain carrier. Here, the common RB may be specified by the index of the RB based on the common reference point of the carrier. The PRB is defined in a certain BWP and may be numbered within the BWP.

[0159] The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). For the UE, one or more BWPs may be set within one carrier.

[0160] At least one of the set BWPs may be active, and the UE may not be assumed to transmit and receive a predetermined signal / channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be read as "BWP".

[0161] The structures such as the above-described radio frames, sub-frames, slots, mini-slots, and symbols are merely examples. For example, the number of sub-frames included in a radio frame, the number of slots per sub-frame or radio frame, the number of mini-slots included in a slot, the number of symbols and RBs included in a slot or mini-slot, the number of sub-carriers included in an RB, and the number of symbols, symbol length, cyclic prefix (CP) length, etc. within a TTI can be changed in various ways.

[0162] In the present disclosure, for example, when an article is added by translation, such as a, an, and the in English, the present disclosure may include that the noun following these articles is in the plural form.

[0163] In the present disclosure, the term "A and B are different" may mean that "A and B are different from each other". Note that the term may also mean that "A and B are different from C respectively". Terms such as "separate", "coupled", etc. may also be interpreted in the same way as "different".

[0164] Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched and used during execution. Also, the notification of predetermined information (for example, the notification of "being X") is not limited to being explicitly performed, and may be performed implicitly (for example, by not performing the notification of the predetermined information).

[0165] Note that the BSB in the present disclosure is an example of the first signal. The eSSB is an example of the second signal.

[0166] As described in detail above, it is obvious to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and changed forms without departing from the spirit and scope of the present disclosure defined by the claims. Therefore, the description of the present disclosure is for illustrative purposes only and has no restrictive meaning for the present disclosure.

Explanation of Reference Numerals

[0167] 10 Base station or gNB 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal or UE 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. a receiving unit that sequentially switches reception beamforming and receives a first signal composed only of a synchronization signal from a base station; a control unit that determines reception beamforming to be applied based on a measurement result of the first signal; and has, the receiving unit applies the determined reception beamforming and receives a second signal composed only of a PBCH (Physical broadcast channel) from the base station, the control unit performs synchronization and cell search using the second signal, a terminal that periodically and alternately repeats reception of the first signal and reception of the second signal using the determined reception beamforming.

2. The terminal according to claim 1, wherein different transmission beamformings are applied to each symbol in the first signal.

3. A transmission unit that applies different transmission beamformings to each symbol and transmits a first signal composed only of a synchronization signal to a terminal, and sequentially switches transmission beamforming to transmit a second signal composed only of a PBCH (Physical broadcast channel) to the terminal; a receiving unit that receives information indicating a measurement result of the second signal from the terminal; a control unit that determines transmission beamforming to be applied based on the information indicating the measurement result; and has, a base station that periodically and alternately repeats transmission of the first signal and transmission of the second signal using the determined transmission beamforming.

4. A communication method executed by a terminal, comprising: sequentially switching reception beamforming and receiving a first signal composed only of a synchronization signal from a base station; determining reception beamforming to be applied based on a measurement result of the first signal; applying the determined reception beamforming and receiving a second signal composed only of a PBCH (Physical broadcast channel) from the base station; performing synchronization and cell search using the second signal; and comprising, a communication method that periodically and alternately repeats reception of the first signal and reception of the second signal using the determined reception beamforming.

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