Base station, terminal device, communication method, and communication program

Abstract

A base station according to the present disclosure comprises a control unit. The control unit transmits, to a terminal device, first information for measuring the communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform. The control unit receives a measurement result of the communication quality performed by the terminal device by using at least one of the first signal waveform and the second signal waveform on the basis of the first information. A signal of the first signal waveform is a multicarrier signal, and a signal of the second signal waveform is a single carrier signal.

Description

Base station, terminal device, communication method, and communication program

[0001] The present disclosure relates to a base station, a terminal device, a communication method, and a communication program.

[0002] Radio access methods and radio networks for cellular mobile communications (hereinafter also referred to as "Long Term Evolution (LTE)," "LTE-Advanced (LTE-A)," "LTE-Advanced Pro (LTE-A Pro)," "New Radio (NR)," "New Radio Access Technology (NRAT)," "Evolved Universal Terrestrial Radio Access (EUTRA)," or "Further EUTRA (FEUTRA)") are being considered by the 3rd Generation Partnership Project (3GPP (registered trademark)).

[0003] In the following description, LTE includes LTE-A, LTE-A Pro, and EUTRA, and NR includes NRAT and FEUTRA. In LTE, a base station (base station device) is referred to as an eNodeB (evolved NodeB), in NR, a base station (base station device) is referred to as a gNodeB, and in LTE and NR, a terminal device (mobile station, mobile station device, terminal) is referred to as a UE (User Equipment). LTE and NR are cellular communication systems in which multiple areas covered by a base station are arranged in the form of cells. A single base station may manage multiple cells.

[0004] 5G NR is a next-generation radio access technology (RAT) different from LTE, and is a next-generation radio access method for LTE. NR is an access technology that can support various use cases, including eMBB (Enhanced mobile broadband), mMTC (Massive machine type communications), and URLLC (Ultra reliable and low latency communications). NR has been standardized to support a technical framework that corresponds to the usage scenarios, requirements, and deployment scenarios of those use cases.

[0005] In recent years, support for high frequency bands such as millimeter waves and terahertz waves and cost reduction of base stations have progressed, which has led to a demand for reduction of the Peak-To-Average-Power Ratio (PAPR) in downlink communications.

[0006] International Publication No. 2023 / 095708

[0007] In order to solve the PAPR problem caused by reducing the cost of base stations as described above, it is necessary to consider means for implementing communications more efficiently.

[0008] Therefore, the present disclosure provides a mechanism that enables more efficient communication in a communication system in which a base station and a terminal device communicate with each other.

[0009] It should be noted that the above problem or object is merely one of multiple problems or objects that can be solved or achieved by multiple embodiments disclosed in this specification.

[0010] A base station according to the present disclosure includes a control unit. The control unit transmits, to a terminal device, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform. The control unit receives, based on the first information, a measurement result of the communication quality performed by the terminal device using at least one of the first signal waveform and the second signal waveform. The signal of the first signal waveform is a multi-carrier signal, and the signal of the second signal waveform is a single-carrier signal.

[0011] 1 is a diagram illustrating an example of signal processing for 5G NR uplink communication. FIG. 1 is a diagram illustrating an overview of a wireless network including a non-terrestrial network. FIG. 2 is a diagram illustrating an overview of satellite communication provided by a communication system. FIG. 3 is a diagram illustrating an example of a cell constituted by a non-geostationary satellite. FIG. 4 is a sequence diagram for explaining an example of a handover flow. FIG. 5 is a sequence diagram for explaining another example of a handover flow. FIG. 6 is a diagram illustrating an example of a communication processing related to a proposed technique of the present disclosure. FIG. 7 is a diagram for explaining an example of the overall configuration of a communication system according to an embodiment of the present disclosure. FIG. 8 is a block diagram illustrating an example of a configuration of a base station according to an embodiment of the present disclosure. FIG. 9 is a block diagram illustrating an example of a configuration of a wireless transmission unit according to an embodiment of the present disclosure. FIG. 10 is a block diagram illustrating an example of a configuration of a first signal waveform transmission unit according to an embodiment of the present disclosure. FIG. 11 is a block diagram illustrating an example of a configuration of a second signal waveform transmission unit according to an embodiment of the present disclosure. FIG. 12 is a block diagram illustrating an example of a configuration of a terminal device according to an embodiment of the present disclosure. FIG. 13 is a block diagram illustrating an example of a configuration of a wireless reception unit according to an embodiment of the present disclosure. FIG. 14 is a block diagram illustrating an example of a configuration of a first signal waveform reception unit according to an embodiment of the present disclosure. FIG. 15 is a block diagram illustrating an example of a configuration of a second signal waveform reception unit according to an embodiment of the present disclosure.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0013] Furthermore, in this specification and drawings, similar components of the embodiments may be distinguished by adding at least one different alphabet and / or number after the same reference numeral. However, if there is no need to particularly distinguish between similar components, only the same reference numeral will be used. For example, multiple components having substantially the same functional configuration may be distinguished as necessary, such as terminal device 50A and terminal device 50B. For example, if there is no need to particularly distinguish between terminal device 50A and terminal device 50B, they will simply be referred to as terminal device 50.

[0014] One or more embodiments (including examples, modifications, and application examples) described below can be implemented independently. However, at least a portion of the embodiments described below may be implemented in appropriate combination with at least a portion of another embodiment. These embodiments may include novel features that are different from each other. Therefore, these embodiments may contribute to solving different purposes or problems and may produce different effects from each other.

[0015] <<1. Introduction>> <1-1. Background> <1-1-1. DFT-S-OFDM Transmission> First, in 5G NR uplink communications, Orthogonal Frequency Division Multiplexing (OFDM) transmission and Discrete Fourier Transform Spread OFDM (DFT-S-OFDM) transmission are used.

[0016] FIG. 1 is a diagram showing an example of signal processing for 5G NR uplink communication.

[0017] As shown in Figure 1, error correction parity bits are added to the transmission signal sequence using error correction coding (channel coding). Then, rate matching is used to extract bits from the transmission signal sequence according to the transmission resource and modulation method. Interleaving and scrambling are applied to the extracted bits.

[0018] Next, the bit sequence is mapped to a complex signal point by modulation processing. When transmission is performed in multiple layers, the bit sequence is mapped to a complex signal point in each layer.

[0019] Here, in DFT-S-OFDM transmission, as shown in Fig. 1, DFT (Discrete Fourier Transformation) processing called Transform precoding is performed. Note that this processing, i.e., the DFT processing performed here, may be called by a name other than Transform precoding. Furthermore, in OFDM transmission, this Transform precoding processing is omitted.

[0020] Then, transmission weights are applied by pre-coding, resource mapping is performed, and then the frequency-domain transmission signal is converted into a time-domain transmission signal (time-axis signal) by OFDM processing and transmitted. Since the processing in Figure 1 is for uplink communication, the time-domain transmission signal is transmitted from the terminal device to the base station.

[0021] At the receiving end, first, the received signal in the time domain is converted into a signal in the frequency domain (frequency axis signal) by OFDM processing, then resource demapping is performed, and frequency equalization processing (equalizer) is performed to compensate for distortion due to radio wave propagation.

[0022] Here, in DFT-S-OFDM transmission, an IDFT (Inverse Discrete Fourier Transformation) process called transform de-precoding is performed, as shown in Fig. 1. In OFDM transmission, this transform de-precoding process is omitted.

[0023] Then, the signals mapped to multiple layers are returned, and soft decisions are made for each bit from the complex signal points. The bit values ​​obtained by this soft decision are then subjected to de-scrambling, de-interleaving, de-rate matching, and error correction decoding (channel decoding) to obtain a received signal sequence.

[0024] As described above, conventionally, a single carrier system (DFT-S-OFDM transmission in the above example) has been introduced in uplink communications in order to reduce PAPR.

[0025] As described above, in recent years, support for high frequency bands such as millimeter waves and terahertz waves and cost reductions in base stations have led to a demand for reduction in PAPR in downlink communications as well.

[0026] Considering the cost reduction and coverage expansion of base stations, it is conceivable to introduce a single carrier system with low PAPR into downlink communications as well.

[0027] <1-1-2. Satellite Communications> Satellite communications is one type of communications that requires a reduction in PAPR. One type of mobile satellite used for satellite communications is a small satellite, also known as a Cube-sat or micro-satellite. Small satellites are inferior to conventional satellites in terms of power and antenna gain. Thus, one of the challenges facing small satellites is the PAPR issue, which arises from the lack of a high-performance power amplifier.

[0028] For this reason, the introduction of a single-carrier system with low PAPR is being considered for satellite communications as well.

[0029] Here, an overview of satellite communications will be described. For example, in cellular mobile communications, a base station (e.g., eNodeB (eNB), gNodeB (gNB), RAN node (including EUTRAN and NGRAN)) or a relay device installed on the ground configures a cell (e.g., macrocell, microcell, femtocell, or small cell) and provides a wireless network. The base station or relay device installed on the ground is also called an earth station.

[0030] The radio network provided by this ground station is called a terrestrial network.

[0031] On the other hand, due to the increasing demand for reducing the cost of base stations and providing coverage to areas where radio waves from base stations are difficult to reach, provision of wireless networks to terminal devices via base stations / relay stations other than terrestrial stations, such as satellite stations and aircraft stations, is being considered. These base stations / relay stations other than terrestrial stations are called non-terrestrial stations (or non-terrestrial base stations / non-terrestrial relay stations).

[0032] In addition, a wireless network provided by a non-terrestrial station is called a non-terrestrial network (NTN).

[0033] Other communication devices besides ground stations include satellite stations and aviation stations. Satellite stations are devices that float outside the atmosphere, such as artificial satellites, and are equipped with wireless communication capabilities. Satellite stations here include low-earth orbiting (LEO) satellites, medium-earth orbiting (MEO) satellites, geostationary-earth orbiting (GEO) satellites, and highly elliptical orbiting (HEO) satellites.

[0034] An aeronautical station is an atmospheric device, such as an aircraft or balloon, that is equipped with radio communication capabilities. In this context, aeronautical stations include unmanned aerial systems (UAS), tethered unmanned aerial systems (TAS), lighter than air UAS (LTA), heavier than air UAS (HTA), and high altitude unmanned aerial system platforms (HAPs).

[0035] In addition, communication devices other than terrestrial stations may also be referred to as base stations (e.g., eNodeB (eNB), gNodeB (gNB), RAN node (including EUTRAN and NGRAN)) from the perspective of cellular mobile communications compliant with 3GPP (registered trademark).

[0036] 2 is a diagram showing an overview of a wireless network including a non-terrestrial network. FIG. 2 shows an example of a wireless network provided by a communication system 1. The communication system 1 of FIG. 2 includes a management device 10 １ and ground station 20 １ ~20 ５ and non-terrestrial station 30 １ ~30 ５ and relay station 40 １ , 40 ２ and the terminal device 50 １ , 50 ２ And, it is equipped with.

[0037] The communication system 1 provides users with a wireless network that enables mobile communication by having the wireless communication devices that make up the communication system 1 operate in cooperation with one another. The wireless network of this embodiment is composed of, for example, a wireless access network and a core network. Note that the wireless communication devices here refer to devices that have wireless communication capabilities, and in the example of Figure 2, these correspond to the terrestrial station 20, the non-terrestrial station 30, the relay station 40, and the terminal device 50.

[0038] The management device 10 is, for example, a device that constitutes a core network CN. The management device 10 is connected to a network PN. The management device 10 is connected to a terrestrial station 20 and a non-terrestrial station 30, and enables a terminal device 50 to connect to the network PN. The network PN is a public data network such as the Internet. The network PN is not limited to the Internet, and may be, for example, a local area network (LAN), a wide area network (WAN), a telephone network (such as a mobile phone network or a fixed telephone network), or a regional Internet Protocol (IP) network. Of course, the network PN may also be another mobile network. For example, the network PN may be a cellular network provided by an entity (e.g., a business entity such as an MNO (Mobile Network Operator)) different from the entity that operates the communication system 1.

[0039] The ground station 20 and the non-ground station 30 are base stations or relay stations. In the following description, the ground station 20 and the non-ground station 30 are assumed to be base stations, but the ground station 20 and the non-ground station 30 may also be relay stations. The ground station 20 is, for example, a terrestrial base station installed on a ground structure, and the non-ground station 30 is, for example, a non-terrestrial base station such as a satellite station or a High Altitude Platform Station (HAPS). The ground station 20 and the non-ground station 30 each constitute a cell. A cell is an area covered by wireless communication. A cell may be any of a macrocell, microcell, femtocell, and small cell. Note that the communication system 1 may be configured so that a single base station (satellite station) manages multiple cells, or so that multiple base stations manage one cell.

[0040] In the example of FIG. １ , 20 ２ constitute a terrestrial network TN1, and the terrestrial station 20 ３ , 20 ４ , 20 ５ constitute the terrestrial network TN2. ２is a network operated by a wireless carrier, such as a telephone company.

[0041] The terrestrial network TN1 and the terrestrial network TN2 may be operated by different wireless carriers or by the same wireless carrier, and the terrestrial network TN1 and the terrestrial network TN2 may be considered as one terrestrial network.

[0042] The terrestrial network TN1 and the terrestrial network TN2 are each connected to a core network. In the example of FIG. 2, the terrestrial station 20 constituting the terrestrial network TN2 is, for example, a management device 10 １ The router 1 is connected to a core network CN1 which is configured by the above.

[0043] Terrestrial Network TN ２ If the radio access method of the terrestrial network TN2 is LTE, the core network CN1 is EPC. Also, if the radio access method of the terrestrial network TN2 is NR, the core network CN1 is 5GC. Of course, the core network CN1 is not limited to EPC or 5GC, and may be a core network of another radio access method.

[0044] 2, the terrestrial network TN1 is not connected to a core network, but the terrestrial network TN1 may be connected to the core network CN1. Also, the terrestrial network TN1 may be connected to a core network (not shown) that is different from the core network CN1.

[0045] The core network CN1 includes, for example, a gateway device and a gateway switch, and is connected to the network PN1 via the gateway device or the gateway switch. As described above, the network PN1 is a public network such as the Internet.

[0046] The gateway device may be a server device connected to the Internet or a local IP network. The gateway switch is, for example, a switch connected to a telephone company's telephone network. １ may have a function as a gateway device or a gateway switch.

[0047] 2 is, for example, a satellite station or an aircraft station. A group of satellite stations (or satellite stations) constituting a non-terrestrial network is called a space-borne platform. Also, a group of aircraft stations (or aircraft stations) constituting a non-terrestrial network is called an airborne platform.

[0048] In the example of FIG. 2, the non-terrestrial station 30 １ , 30 ２ , 30 ３ constitute the spaceborne platform SBP1, and the non-ground station 30 ４ The spaceborne platform SBP2 is composed of the non-ground station 30. ５ constitutes the Airborne Platform ABP1.

[0049] The non-terrestrial station 30 may be able to communicate with the terrestrial network or the core network via the relay station 40. Of course, the non-terrestrial station 30 may also be able to communicate directly with the terrestrial network or the core network without going through the relay station 40.

[0050] The non-terrestrial stations 30 may be able to communicate with the terminal device 50 via the relay station 40, or may be able to communicate directly with the terminal device 50. Furthermore, the non-terrestrial stations 30 may be able to communicate directly with each other without going through the relay station 40.

[0051] The relay station 40 relays communication between the terrestrial device and the non-terrestrial station 30. The relay station is also called an earth station (Very Small Aperture Terminal, Gateway, Control Earth Station, HUB Station). The relay station 40 may be a terrestrial station or a non-terrestrial station. In the example of FIG. 2, the relay station 40 ２ relays communications between the ground station 20 and the non-ground station 30, and the relay station 40 １ relays communications between the management device 10 and the non-terrestrial station 30 .

[0052] The relay station 40 may relay communication between the terminal device 50 and the non-terrestrial station 30. The relay station 40 may also be capable of communicating with other relay stations 40.

[0053] The terminal device 50 can communicate with both terrestrial stations and non-terrestrial stations. In the example of FIG. １ can communicate with the terrestrial stations that make up the terrestrial network TN1. １ can communicate with non-ground stations that make up the spaceborne platforms SBP1 and SBP2.

[0054] The terminal device 50 can also communicate with non-ground stations that constitute the airborne platform ABP1. The terminal device 50 may also be able to communicate with the relay station 40. The terminal device 50 may also be able to directly communicate with other terminal devices 50. １ is the terminal device 50 ２ It may be possible to communicate directly with

[0055] Examples of terminal devices 50 (terrestrial terminal devices) compatible with non-terrestrial networks include mobile phones, smartphones, automobiles, buses, trains, airplanes, M2M (Machine to Machine) / IoT (Internet of Things) devices, relay stations that relay satellite communications, and base stations that receive satellite communications.

[0056] Each device constituting the spaceborne platforms SBP1 and SBP2 performs satellite communication with the terminal device 50. Satellite communication refers to wireless communication between a satellite station and a communication device.

[0057] 3 is a diagram showing an overview of satellite communication provided by the communication system 1. Satellite stations are mainly divided into geostationary satellite stations and low-earth orbit satellite stations.

[0058] A geostationary satellite station is a satellite station located in a geostationary orbit and revolving around the Earth at the same speed as the Earth's rotation. In the example of FIG. 3, the non-ground station 30 constituting the spaceborne platform SBP2 ４ A geostationary satellite station is a satellite orbit that is located at an altitude of approximately 35,786 km.

[0059] A geostationary orbit is also called a geostationary earth orbit (GEO). The relative velocity of a geostationary satellite station with respect to a terrestrial terminal device 50 is nearly zero, and the geostationary satellite station is observed by the terrestrial terminal device 50 as if it were stationary. ４ is a terminal device 50 located on the earth. １ , 50 ３ , 50 ４ etc., and conducts satellite communications.

[0060] The low-earth orbit satellite station is a satellite station that orbits in a low orbit. In the example of FIG. 3, the non-ground station 30 constituting the spaceborne platform SBP1 １ , 30 ２ These are low-earth orbit satellite stations. A low-earth orbit is a satellite orbit with an altitude of approximately 2,000 km or less. A low-earth orbit is also called a low-earth orbit (LEO).

[0061] Unlike geostationary satellite stations, low-earth orbit satellite stations have a relative velocity with respect to the terrestrial terminal device 50, and are observed by the terrestrial terminal device 50 as if they are moving. １ , 30 ２ Each cell is composed of a terminal device 50 located on the earth. １ , 50 ３ , 50 ４ etc., and conducts satellite communications.

[0062] 3, a non-terrestrial station 30 is shown as a satellite station constituting the spaceborne platform SBP1. １ , 30 ２ However, in reality, a satellite constellation is formed by many satellite stations. In this case, the number of satellite stations constituting the spaceborne platform SBP1 is three or more (for example, several tens to several thousands).

[0063] In the example of Fig. 3, only geostationary satellite stations and low-earth orbit satellite stations are shown as satellite stations, but the satellite stations constituting the communication system 1 may also include medium-earth orbit satellite stations. A medium-earth orbit satellite station is a satellite station that orbits in a medium orbit. A medium orbit is an orbit located between a low orbit and a geostationary orbit. A medium orbit is also called a medium Earth orbit (MEO).

[0064] In addition, the satellite stations constituting the communication system 1 may include highly elliptical orbit (HEO) satellite stations located in highly elliptical orbits. Note that the satellite stations forming the satellite constellation may include not only low-earth orbit satellite stations, but also medium-earth orbit satellite stations, highly elliptical orbit satellite stations, and geostationary satellite stations.

[0065] 4 is a diagram showing an example of a cell formed by a non-geostationary satellite. ２ In the example of FIG. 4, a cell C formed by the non-terrestrial station 30 ２ is a low-earth orbit satellite station. A satellite station orbiting in a low-earth orbit has a predetermined directivity to the earth and communicates with a terminal device 50 on the ground.

[0066] For example, in the example shown in Figure 4, the angle R is 40°. ２ The radius D of the cell C formed by the low-earth orbit satellite station is, for example, 1000 km. The low-earth orbit satellite station moves at a constant speed. If it becomes difficult for the low-earth orbit satellite station to provide satellite communications to the terminal device 50 on the ground, a subsequent low-earth orbit satellite station (neighbor satellite station) will provide the satellite communications.

[0067] In the example of FIG. 4, the non-terrestrial station 30 ２ If it becomes difficult for the satellite station 30 to provide satellite communications to the terrestrial terminal 50, the subsequent non-terrestrial station 30 ３ The above values ​​of angle R and radius D are merely examples and are not limited to the above.

[0068] Medium- and low-earth orbit satellites move in orbit at extremely high speeds. For example, a low-earth orbit satellite at an altitude of 600 km moves in orbit at a speed of 7.6 km / s.

[0069] Low-earth orbit satellites form cells (or beams) on the ground with a radius of several tens to several hundreds of kilometers, but since the cells formed on the ground also move in accordance with the movement of the satellite, handover may be necessary even if the terminal device on the ground is not moving. For example, assuming a case where the diameter of the cell formed on the ground is 50 km and the terminal device on the ground is not moving, handover occurs in approximately 6 to 7 seconds.

[0070] As described above, the terminal device 50 is capable of wireless communication using a non-terrestrial network. Furthermore, the non-terrestrial station 30 of the communication system 1 constitutes a non-terrestrial network. This enables the communication system 1 to extend services to the terminal device 50 located in an area that cannot be covered by the terrestrial network.

[0071] For example, the communication system 1 can provide services to terminal devices 50 in areas that cannot be covered by a terrestrial network (e.g., out of coverage of a cell provided by the terrestrial station 20). The communication system 1 can provide public safety communication and critical communication to communication devices such as IoT (Internet of Things) devices and MTC (Machine Type Communications) devices.

[0072] Furthermore, the use of a non-terrestrial network improves service reliability and recovery, thereby enabling the communication system 1 to reduce the vulnerability of the service to physical attacks or natural disasters.

[0073] The communication system 1 can also provide service connections to aircraft terminal devices such as airplane passengers and drones, and to mobile terminal devices such as ships and trains. The communication system 1 can also provide highly efficient multicast services and highly efficient broadcast services, such as A / V content, group communication, IoT broadcast services, software download services, and emergency messages. Furthermore, the communication system 1 can also provide traffic offload between terrestrial networks and non-terrestrial networks.

[0074] Although satellite communication has been cited here as an example of wireless communication that employs a single carrier scheme in downlink communication, wireless communication that employs a single carrier scheme is not limited to satellite communication. In other words, the technology according to this embodiment is not limited to application to non-terrestrial networks, but can also be applied to terrestrial networks.

[0075] In the following, for the sake of simplicity, the technology according to this embodiment will be described using downlink communication in a terrestrial network as an example, but the technology according to this embodiment can also be applied to downlink communication in a non-terrestrial network.

[0076] <1-1-3. Handover> As described above, when a single-carrier system is introduced into downlink communication, a multi-carrier system (for example, the above-mentioned OFDM transmission) and a single-carrier system (for example, the above-mentioned DFT-S-OFDM transmission) will coexist.

[0077] Here, the terminal device 50 performs measurement to measure the communication quality of downlink communication and reports the measurement results (Measurement Report) to the base station 20. Here, the measurement results of the communication quality are used for communication with the base station 20 (for example, downlink communication) and for handover determination.

[0078] Hereinafter, a conventional handover process will be described as an example of a process using communication quality.

[0079] Fig. 5 is a sequence diagram for explaining an example of a flow of handover. Fig. 5 illustrates a case where a terminal device 50 performs handover from a serving (source) cell of a serving (source) base station, which is a handover source, to a target cell of a target base station, which is a handover destination.

[0080] 5, the terminal device 50 performs measurements (measurement control) and transmits a measurement report to the serving base station (step S101). Similarly, the terminal device 50 performs measurements and transmits a measurement report to the target base station (step S102).

[0081] The serving base station determines whether or not handover of the terminal device 50 is necessary based on the measurement report (step S103). If the serving base station determines that handover is necessary, it requests handover from the target base station (step S104).

[0082] Upon receiving the handover request, the target base station performs admission control (step S105) and sends an acknowledgement to the handover request to the serving base station (step S106).

[0083] Next, the serving base station transmits an RRC Reconfiguration including a handover command to the terminal device 50 (step S107), and notifies the terminal device 50 of the execution of handover.

[0084] Upon receiving the RRC Reconfiguration, the terminal device 50 detaches from the serving cell of the serving base station (step S108) and performs an initial access procedure with the target base station. For example, the terminal device 50 transmits a PRACH (Physical Random Access Channel) to the target base station (step S109).

[0085] The target base station transmits a Random Access response to the terminal device 50 (step S110). When the terminal device 50 transmits a Random Access response to the target base station (step S111), the initial access procedure is completed, and the handover process is also completed.

[0086] Although the case where the terminal device 50 performs a two-step random access procedure (2-step RACH) as the initial access procedure has been described here, the present invention is not limited to this. The terminal device 50 may perform a four-step random access procedure (4-step RACH) as the initial access procedure.

[0087] In this way, in the handover shown in FIG. 5, the terminal device 50 starts handover at the timing when it receives a handover command from the serving base station.

[0088] Another example of handover is conditional handover, in which the serving base station notifies the terminal device 50 in advance of information about handover candidate destinations.

[0089] Fig. 6 is a sequence diagram for explaining another example of the flow of handover. Fig. 6 shows a case where the terminal device 50 selects either the first or second target base station, which is a candidate for the handover destination, and executes the handover. Note that the first target base station has a target candidate cell #1, and the second target base station has a target candidate cell #2.

[0090] As shown in FIG. 6, the terminal device 50 performs measurements and transmits a measurement report to the serving base station (step S201).

[0091] The serving base station determines whether or not a conditional handover is necessary for the terminal device 50 based on the measurement report (step S202). If the serving base station determines that a conditional handover is necessary, it requests a handover from the first target base station (step S203) and requests a handover from the second target base station (step S204).

[0092] Upon receiving the handover request, the first target base station performs admission control (step S205). Similarly, upon receiving the handover request, the second target base station performs admission control (step S206). The first target base station notifies the serving base station of an acknowledgment of the handover request (step S207). The second target base station notifies the serving base station of an acknowledgment of the handover request (step S208).

[0093] Next, the serving base station transmits RRC Reconfiguration to the terminal device 50 (step S209). The RRC Reconfiguration includes, for example, information on the first and second target base stations that are candidates for the handover destination, and information on an implementation trigger for implementing a conditional handover.

[0094] When the terminal device 50 receives the RRC Reconfiguration, it transmits an RRC Reconfiguration complete to the serving base station (step S210) and evaluates an implementation trigger for performing a conditional handover (step S211). The terminal device 50 evaluates the implementation trigger, and when the implementation trigger is detected (step S212), it detaches from the serving cell (serving base station) (step S213) and starts an initial connection procedure with the handover destination base station. Note that in FIG. 6, it is assumed that the first target base station is detected as the handover destination base station.

[0095] 6, the terminal device 50 executes an initial connection procedure with the first target base station. The initial connection procedure is the same as the procedure shown in FIG.

[0096] After completing the initial connection procedure and connecting with the terminal device 50, the first target base station notifies the serving base station of "Handover Success," indicating that the handover was successful (step S214). The serving base station that has received the "Handover Success" notification cancels the handover to the second target base station by notifying "Handover Cancel" to the second target base station that was not selected as the handover destination (step S215).

[0097] In this way, in conditional handover, the serving base station does not decide the target base station to which the handover is to be performed, but notifies the terminal device 50 of candidate target base stations. This allows the terminal device 50 to select a target base station that can be connected to at the time of performing the handover and perform the handover.

[0098] In addition, in the conditional handover, in order to realize a seamless handover, the terminal device 50 detects an execution trigger for the conditional handover in step S212 of Fig. 6, for example, and then detaches from the serving base station in the next step S213. In other words, in order to avoid a period during which communication with all of the serving base station and target base station candidates is impossible, and a period during which initial connection cannot be performed, the terminal device 50 detects an execution trigger for the conditional handover in step S212 of Fig. 6, for example, and then detaches from the serving base station in the next step S213.

[0099] In this way, the terminal device 50 and / or the serving base station use the measurement (measurement of communication quality) results to determine whether to perform a handover.

[0100] <1-2. Issues> As described above, when a single-carrier system is introduced into downlink communication of communication system 1, a multi-carrier system (for example, the above-mentioned OFDM transmission) and a single-carrier system (for example, the above-mentioned DFT-S-OFDM transmission) will coexist.

[0101] As described above, in order to determine handover or the like, the terminal device 50 measures the reference signal and reports the measurement results (measurement report).

[0102] In a communication system in which both the multi-carrier system and the single-carrier system are implemented, a mechanism is required for the terminal device 50 to perform measurements and measurement reports.

[0103] 7 is a diagram showing an example of a communication process according to the proposed technique of the present disclosure. １ , 20 ２ and the terminal device 50.

[0104] Base station 20 １ is a serving base station that provides a serving cell.２ is a target base station that serves a neighboring cell of the serving cell or a target cell. For example, when the above-mentioned conditional handover is performed, the base station 20 ２ is a target base station that provides a neighboring cell of the serving cell. When a normal handover is performed, not the above-mentioned conditional handover, the base station 20 ２ is the target base station that provides the target cell.

[0105] As shown in FIG. １ base station 20 ２ Waveform information on signal waveforms that can be used for downlink communication of the neighboring cell or the target cell is acquired from the neighboring cell or the target cell (step S11). The waveform information includes, for example, information on at least one of a first signal waveform and a second signal waveform. The first signal waveform is, for example, a waveform of a multi-carrier signal, and the second signal waveform is, for example, a waveform of a single-carrier signal.

[0106] Base station 20 １ The base station 20 transmits measurement information (an example of first information) for measuring the communication quality of the downlink communication to the terminal device 50 (step S12). １ is the base station 20 ２ That is, the measurement information includes, for example, information on at least one of the first signal waveform and the second signal waveform (an example of second information).

[0107] Base station 20 ２ The base station 20 transmits a signal (reference signal) for measuring the communication quality of the downlink communication (step S13). ２ transmits, for example, a reference signal of a first signal waveform (dotted line in FIG. 7) and a reference signal of a second signal waveform (chain line in FIG. 7).

[0108] In FIG. 7, the base station 20 ２ transmits both a reference signal of the first signal waveform and a reference signal of the second signal waveform, but ２may transmit one of a reference signal having a first signal waveform and a reference signal having a second signal waveform.

[0109] The terminal device 50 measures the communication quality of the downlink communication based on the reference signal and reports the measurement result to the base station 20. １ (step S14).

[0110] For example, the terminal device 50 receives a reference signal of a first signal waveform using a resource corresponding to the measurement information and measures a first communication quality. Also, for example, the terminal device 50 receives a reference signal of a second signal waveform using a resource corresponding to the measurement information and measures a second communication quality. The terminal device 50 transmits measurement information relating to the first communication quality and the second communication quality to the base station 20. １ Report to.

[0111] Base station 20 １ determines to perform handover of the terminal device 50 based on the measurement information, and notifies the terminal device 50 of instruction information instructing handover (for example, a handover command) (step S15).

[0112] The terminal device 50 that has received the instruction information １ to base station 20 ２ Then, the handover to the next terminal is performed (step S16).

[0113] As described above, in the communication system according to the proposed technique of the present disclosure, the base station 20 １ notifies the terminal device 50 of measurement information (corresponding to first information) for measurement (measurement of communication quality of downlink communication). This measurement information includes information on at least one of the first signal waveform and the second signal waveform.

[0114] Therefore, by receiving the measurement information, the terminal device 50 can receive at least one of the reference signal of the first signal waveform and the reference signal of the second signal waveform, and can perform measurements.

[0115] Base station 20 １ The base station 20 can receive a measurement report from the terminal device 50. １can perform actions (e.g., downlink communication, handover decision, etc.) based on the measurement report.

[0116] In the following embodiments, the base station 20 can be implemented as a terrestrial base station, a satellite station, or a non-terrestrial base station 30 that operates as a communication device, such as a drone, a balloon, or an airplane.

[0117] Furthermore, in the following embodiments, when specific examples are given, there are some places where specific values ​​are given for explanation, but the values ​​do not depend on the examples, and other values ​​may be used.

[0118] Furthermore, in this embodiment, resources represent Frequency, Time, Resource Element (including REG, CCE, and CORESET), Resource Block, Bandwidth Part, Component Carrier, Symbol, Sub-Symbol, Slot, Mini-Slot, Non-slot, Subslot, Subframe, Frame, PRACH occasion, Occasion, Code, Multi-access physical resource, Multi-access signature, Subcarrier Spacing (Numerology), etc.

[0119] In the following embodiments, CP-OFDM is used as a multi-carrier scheme (first signal waveform) and DFT-S-OFDM is used as a single-carrier scheme (second signal waveform). The above-mentioned CP-OFDM and DFT-S-OFDM are examples, and the multi-carrier scheme and single-carrier scheme are not limited to these.

[0120] As described above, in the case of a single-carrier system (second signal waveform), transform precoding is applied in transmission signal processing, and in the case of a multi-carrier system (first signal waveform), transform precoding is not applied (see FIG. 1).

[0121] Therefore, processing related to the single-carrier system (DFT-S-OFDM) can be interpreted as processing to which Transform precoding is applied, and processing related to the multi-carrier system (CP-OFDM) can be interpreted as processing to which Transform precoding is not applied.

[0122] In addition, in the following embodiments, the handover command (the above-mentioned instruction information) can be read as RRC reconfiguration or the like.

[0123] 2. Example of a configuration of a communication system 2-1. Example of an overall configuration of a communication system Fig. 8 is a diagram for explaining an example of an overall configuration of a communication system SYS1 according to an embodiment of the present disclosure. As shown in Fig. 8, the communication system SYS1 according to this embodiment includes a base station 20 and a plurality of terminal devices 50A and 50B.

[0124] The communication system SYS1 may include the management device 10, the non-terrestrial station 30, the relay station 40 (see FIG. 2), and the like.

[0125] (Base Station 20) The base station 20 is a communication device that operates a cell C1 and provides wireless communication services to one or more terminal devices 50 located within the coverage of the cell C1. The cell C1 is operated according to any wireless communication method, such as LTE or NR. The base station 20 is connected to a core network. The core network is connected to a packet data network (not shown) via a gateway device (not shown). The base station 20 also operates beams that can be identified by SSB (Synchronization Signal / PBCH Block), and can transmit and receive data to and from one or more terminal devices 50 via one or more beams.

[0126] The base station 20 may be configured as a collection of multiple physical or logical devices. For example, in this embodiment, the base station 20 may be divided into multiple devices, a baseband unit (BBU) and an RU, and may be interpreted as a collection of these multiple devices. Additionally or alternatively, in this embodiment, the base station 20 may be either or both of a BBU and an RU. The BBU and the RU may be connected via a predetermined interface (e.g., eCPRI). Additionally or alternatively, the RU may be referred to as a remote radio unit (RRU) or a radio DoT (RD). Additionally or alternatively, the RU may be compatible with a gNB-DU (gNB-CU) (described later). Additionally or alternatively, the BBU may be compatible with a gNB-CU (gNB-CU) (described later). Alternatively, the RU may be connected to a gNB-DU (gNB-DU) (described later). Furthermore, the BBU may be compatible with a combination of a gNB-CU and a gNB-DU (gNB-DU) (described later). Additionally or alternatively, the RU may be a device integrally formed with an antenna. The antennas of the base station 20 (e.g., antennas integrally formed with the RUs) may employ an Advanced Antenna System and support MIMO (e.g., FD-MIMO) and beamforming. In the Advanced Antenna System, the antennas of the base station 20 (e.g., antennas integrally formed with the RUs) may include, for example, 64 transmitting antenna ports and 64 receiving antenna ports.

[0127] Furthermore, multiple base stations 20 may be connected to each other. One or more base stations 20 may be included in a Radio Access Network (RAN). That is, the base station 20 may simply be referred to as a RAN, a RAN node, an Access Network (AN), or an AN node. The RAN in LTE is called an Enhanced Universal Terrestrial RAN (EUTRAN). The RAN in NR is called an NGRAN. The RAN in W-CDMA (UMTS) is called a UTRAN. The base station 20 in LTE is called an eNodeB (Evolved Node B) or eNB. That is, the EUTRAN includes one or more eNodeBs (eNBs). Furthermore, the base station 20 in NR is called a gNodeB or gNB. That is, the NGRAN includes one or more gNBs. Furthermore, the EUTRAN may include a gNB (en-gNB) connected to a core network (EPC) in an LTE communication system (EPS). Similarly, the NGRAN may include an ng-eNB connected to a core network (5GC) in a 5G communication system (5GS). Additionally or alternatively, if the base station 20 is an eNB, gNB, or the like, it may be referred to as a 3GPP access. Additionally or alternatively, if the base station 20 is a wireless access point (e.g., a WiFi (registered trademark) access point), it may be referred to as a non-3GPP access. Additionally or alternatively, the base station 20 may be an optical extension device called an RRH (Remote Radio Head). Additionally or alternatively, if the base station 20 is a gNB, it may be referred to as a combination of the aforementioned gNB CU (Central Unit) and gNB DU (Distributed Unit), or as either one of them. The gNB CU hosts multiple upper layers (e.g., RRC, SDAP, PDCP) in the Access Stratum for communication with the UE, while the gNB-DU hosts multiple lower layers (e.g., RLC, MAC, PHY) in the Access Stratum.That is, among the messages and information described below, RRC signaling (e.g., various SIBs including MIB and SIB1, RRC Setup message, RRC Reconfiguration message) may be generated by the gNB CU, while the DCI and various physical channels (e.g., PDCCH and PBCH) described below may be generated by the gNB-DU. Alternatively, among the RRC signaling, some configuration (setting information), such as IE:cellGroupConfig, may be generated by the gNB-DU, and the remaining configuration may be generated by the gNB-CU. These configurations (setting information) may be transmitted and received via the F1 interface described below. A base station 20 may be configured to be able to communicate with other base stations 20. For example, when multiple base stations 20 are eNBs or a combination of an eNB and an en-gNB, the base stations 20 may be connected to each other via an X2 interface. Additionally or alternatively, when multiple base stations 20 are gNBs or a combination of a gn-eNB and a gNB, the devices may be connected to each other via an Xn interface. Additionally or alternatively, when multiple base stations 20 are a combination of gNB CU and gNB DU, the devices may be connected via the F1 interface described above. Messages and information (RRC signaling or DCI information, physical channel) described below may be communicated between multiple base stations 20 (e.g., via X2, Xn, or F1 interfaces).

[0128] Furthermore, as described above, the base station 20 may be configured to manage multiple cells C1. The cell C1 provided by the base station 20 is called a serving cell. The serving cell includes a PCell (Primary Cell) and an SCell (Secondary Cell). When dual connectivity (e.g., EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5GC, NR-EUTRA Dual Connectivity (NEDC), NR-NR Dual Connectivity) is provided to a UE (e.g., a terminal device 50), the PCell and zero or one or more SCell(s) provided by a Master Node (MN) are called a Master Cell Group. Furthermore, the serving cell may include a PSCell (Primary Secondary Cell or Primary SCG Cell). That is, when dual connectivity is provided to a UE, the PSCell and zero or one or more SCell(s) provided by a Secondary Node (SN) are called a Secondary Cell Group (SCG). Unless a special configuration (for example, PUCCH on SCell) is performed, the physical uplink control channel (PUCCH) is transmitted on the PCell and PSCell, but not on the SCell. Furthermore, radio link failure is detected on the PCell and PSCell, but not on the SCell (it does not have to be detected). Since the PCell and PSCell thus play special roles among the serving cell(s), they are also called special cells (SpCells). One cell C1 may be associated with one downlink component carrier and one uplink component carrier. Furthermore, the system bandwidth corresponding to one cell C1 may be divided into multiple bandwidth parts.In this case, one or more Bandwidth Parts (BWP) may be configured in the UE, and one Bandwidth Part may be used by the UE as an Active BWP. Furthermore, radio resources (e.g., frequency band, numerology (subcarrier spacing), slot format (Slot configuration)) that the terminal device 50 can use may differ for each cell C1, each component carrier, or each BWP.

[0129] The base station 20 determines a signal waveform to be used for downlink communication with the terminal device 50 from among a plurality of signal waveforms including a single-carrier signal. For example, the base station 20 determines to use either a single-carrier signal or a multi-carrier signal for downlink communication.

[0130] The base station 20 determines, for example, a signal waveform to be used for each terminal device 50, and notifies information about the determined signal waveform to the terminal device 50. The base station 20 performs downlink communication with the terminal device 50 using the notified signal waveform.

[0131] 8, the base station 20 selects a multi-carrier signal to perform downlink communication S1 for a terminal device 50A located near the center of cell C1, and also selects a single-carrier signal to perform downlink communication S2 for a terminal device 50B located near the edge of cell C1.

[0132] In order to perform downlink communication with the terminal device 50B located closer to the cell edge, a larger transmission power is required, and a low PAPR is required. On the other hand, for the terminal device 50A located closer to the center of the cell C1, the required transmission power is smaller than that at the cell edge, so it is easier to ensure the required transmission power even if the PAPR is high.

[0133] Therefore, the base station 20 selects a multi-carrier signal for the terminal device 50A located towards the center of the cell C1, and selects a single-carrier signal for the terminal device 50B located towards the edge of the cell C1, for example.

[0134] In this way, the base station 20 allocates a single-carrier signal to downlink communications that strictly require a low PAPR, and allocates a signal waveform other than a single-carrier signal (here, a multi-carrier signal) to downlink communications that do not require a low PAPR, thereby enabling the base station 20 to achieve a low PAPR and improve the efficiency of the entire system.

[0135] Here, a case has been described in which the base station 20 determines the signal waveform depending on the position of the terminal device 50 in the cell C1, but the method of determining the signal waveform by the base station 20 is not limited to this.

[0136] 9 is a block diagram showing a configuration example of a base station 20 according to an embodiment of the present disclosure. As shown in FIG. 9, the base station 20 includes an upper layer processing unit 101, a control unit 103, a receiving unit 105, a transmitting unit 107, and a transmitting / receiving antenna 109.

[0137] The base station 20 may support one or more RATs (Radio Access Technologies). For example, the base station 20 may support both LTE and NR. In this case, some or all of the units included in the base station 20 may be configured individually according to the RAT. For example, the receiving unit 105 and the transmitting unit 107 may be configured individually for LTE and NR.

[0138] In addition, in an NR cell, some or all of the units included in base station 20 shown in Figure 9 can be individually configured according to a parameter set related to a transmission signal. For example, in a certain NR cell, radio receiving unit 1057 and radio transmitting unit 1077 can be individually configured according to a parameter set related to a transmission signal.

[0139] (Upper Layer Processing Section) The upper layer processing section 101 outputs downlink data (transport blocks) to the control section 103. The upper layer processing section 101 performs processing of the Medium Access Control (MAC) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Radio Resource Control (RRC) layer. The upper layer processing section 101 also generates control information for controlling the receiving section 105 and the transmitting section 107, and outputs the control information to the control section 103.

[0140] The upper layer processing unit 101 performs processing and management related to RAT control, radio resource control, subframe configuration, scheduling control, and / or CSI reporting control. The processing and management in the upper layer processing unit 101 is performed for each terminal device 50 or commonly for all terminal devices 50 connected to the base station 20.

[0141] The processing and management in the upper layer processing unit 101 may be performed solely by the upper layer processing unit 101, or may be acquired from an upper node or another base station 20. The processing and management in the upper layer processing unit 101 may also be performed individually depending on the RAT. For example, the upper layer processing unit 101 performs processing and management in LTE and processing and management in NR separately.

[0142] In the RAT control in the upper layer processing unit 101, management related to the RAT is performed. For example, in the RAT control, management related to LTE and / or management related to NR is performed. Management related to NR includes setting and processing of parameter sets related to transmission signals in NR cells.

[0143] The radio resource control in the upper layer processing unit 101 manages configuration information in the own device. The radio resource control in the upper layer processing unit 101 generates and / or manages downlink data (transport blocks), system information, RRC messages (RRC parameters), and / or MAC control elements (CEs).

[0144] The subframe configuration in the upper layer processing unit 101 involves management of subframe configuration, subframe pattern configuration, uplink / downlink configuration, uplink reference UL-DL configuration, and / or downlink reference UL-DL configuration.

[0145] The subframe setting in the upper layer processing unit 101 is also referred to as base station subframe setting. The subframe setting in the upper layer processing unit 101 can be determined based on the amount of uplink traffic and the amount of downlink traffic.

[0146] In addition, the subframe setting in the upper layer processing unit 101 can be determined based on the scheduling results of the scheduling control in the upper layer processing unit 101.

[0147] In the scheduling control in the upper layer processing unit 101, the frequency and subframe to which the physical channel is assigned, the coding rate, modulation scheme, and transmission power of the physical channel, etc. are determined based on the received channel state information and the propagation path estimate value and channel quality input from the channel measurement unit 1059. For example, the control unit 103 generates control information (DCI format) based on the scheduling result of the scheduling control in the upper layer processing unit 101.

[0148] The CSI reporting control in the upper layer processing unit 101 controls the CSI reporting of the terminal device 50. For example, the setting related to the CSI reference resource to be assumed for calculating the CSI in the terminal device 50 is controlled.

[0149] (Control Unit) The control unit 103 controls the receiving unit 105 and the transmitting unit 107 based on control information from the upper layer processing unit 101. The control unit 103 generates control information for the upper layer processing unit 101 and outputs it to the upper layer processing unit 101.

[0150] The control unit 103 receives the decoded signal from the decoding unit 1051 and the channel estimation result from the channel measurement unit 1059. The control unit 103 outputs the signal to be coded to the coding unit 1071. The control unit 103 is also used to control the whole or part of the base station 20.

[0151] Furthermore, the control unit 103 determines the signal waveform (hereinafter also referred to as the signal waveform to be used) to be used for downlink communication with the terminal device 50 from among the single-carrier signal and the multi-carrier signal.

[0152] The control unit 103 controls the transmission unit 107 to notify the terminal device 50 of information related to the signal waveform to be used by using a predetermined signal waveform (for example, a single carrier signal). The control unit 103 also controls the transmission unit 107 to perform downlink communication with the terminal device 50 by using the notified signal waveform to be used.

[0153] (Receiving unit) The receiving unit 105 receives signals transmitted from the terminal device 50 via the transmitting / receiving antenna 109 in accordance with control from the control unit 103, and further performs receiving processing such as separation, demodulation, and decoding, and outputs the received and processed information to the control unit 103.

[0154] The reception process in the receiving unit 105 is performed based on a predetermined setting or a setting notified to the terminal device 50 by the base station 20 .

[0155] The receiving unit 105 includes a decoding unit 1051 , a demodulating unit 1053 , a demultiplexing unit 1055 , a radio receiving unit 1057 , and a channel measuring unit 1059 .

[0156] (Radio Receiving Unit) The radio receiving unit 1057 performs the following operations on the uplink signal received via the transmitting / receiving antenna 109: converting to an intermediate frequency (down-converting), removing unnecessary frequency components, controlling the amplification level so that the signal level is maintained appropriately, performing quadrature demodulation based on the in-phase and quadrature components of the received signal, converting the analog signal to a digital signal, removing the guard interval (GI), and / or extracting a frequency domain signal using a fast Fourier transform (FFT).

[0157] (Demultiplexing Unit) The demultiplexing unit 1055 separates an uplink channel such as a PUCCH or a PUSCH and / or an uplink reference signal from the signal input from the radio receiving unit 1057. The demultiplexing unit 1055 outputs the uplink reference signal to the channel measurement unit 1059. The demultiplexing unit 1055 performs propagation path compensation for the uplink channel based on the propagation path estimate input from the channel measurement unit 1059.

[0158] (Demodulation Unit) The demodulation unit 1053 demodulates the received signal using a modulation method such as BPSK (Binary Phase Shift Keying), π / 2BPSK, QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), 64QAM, 256QAM, etc. The demodulation unit 1053 separates and demodulates the MIMO-multiplexed uplink channel.

[0159] (Decoding Unit) The decoding unit 1051 performs decoding processing on the coded bits of the demodulated uplink channel. The decoded uplink data and / or uplink control information is output to the control unit 103. The decoding unit 1051 performs decoding processing on the PUSCH for each transport block.

[0160] (Channel Measurement Unit) The channel measurement unit 1059 measures an estimated value of a propagation path and / or channel quality from the uplink reference signal input from the demultiplexing unit 1055, and outputs the results to the demultiplexing unit 1055 and / or the control unit 103. For example, the channel measurement unit 1059 measures an estimated value of a propagation path for performing propagation path compensation for a PUCCH or a PUSCH using an UL-DMRS, and measures the quality of the uplink channel using an SRS.

[0161] (Transmitting Unit) The transmitting unit 107 performs transmission processing such as coding, modulation, and multiplexing on the downlink control information and downlink data input from the upper layer processing unit 101, in accordance with control from the control unit 103. For example, the transmitting unit 107 generates and multiplexes the PHICH, the PDCCH, the EPDCCH, the PDSCH, and the downlink reference signal to generate a transmission signal.

[0162] The transmission processing in the transmitting unit 107 is performed based on predefined settings, settings notified to the terminal device 50 by the base station 20, or settings notified via the PDCCH or EPDCCH transmitted in the same subframe.

[0163] The transmitting unit 107 includes an encoding unit 1071 , a modulation unit 1073 , a multiplexing unit 1075 , a radio transmitting unit 1077 , and a downlink reference signal generating unit 1079 .

[0164] (Encoding unit) The encoding unit 1071 encodes the HARQ indicator (HARQ-ACK), downlink control information, and downlink data input from the control unit 103 using a predetermined encoding method such as block coding, convolutional coding, turbo coding, etc.

[0165] (Modulation Unit) The modulation unit 1073 modulates the coded bits input from the coding unit 1071 using a predetermined modulation method such as BPSK, π / 2BPSK, QPSK, 16QAM, 64QAM, or 256QAM.

[0166] (Downlink Reference Signal Generator) The downlink reference signal generator 1079 generates a downlink reference signal based on a physical cell identification (PCI), RRC parameters set in the terminal device 50, and the like.

[0167] (Multiplexing Unit) The multiplexing unit 1075 multiplexes the modulation symbols of each channel and the downlink reference signal, and arranges the multiplexed symbols in predetermined resource elements.

[0168] (Radio Transmission Unit) The radio transmission unit 1077 converts the signal from the multiplexing unit 1075 into a time domain signal using an inverse fast Fourier transform (IFFT), adds a guard interval, and generates a baseband digital signal. The radio transmission unit 1077 also performs processes such as conversion to an analog signal, quadrature modulation, conversion from an intermediate frequency signal to a high frequency signal (up-conversion), removal of unnecessary frequency components, and power amplification to generate a transmission signal. The transmission signal output by the radio transmission unit 1077 is transmitted from the transmission / reception antenna 109.

[0169] Here, the radio transmission unit 1077 according to this embodiment can support a plurality of downlink signal waveforms. The radio transmission unit 1077 in the base station 20 that supports both the first signal waveform (multi-carrier signal) and the second signal waveform (single-carrier signal) will be described in detail with reference to Figures 10 to 12.

[0170] 10 is a block diagram showing an example configuration of the wireless transmission unit 1077 according to an embodiment of the present disclosure. The wireless transmission unit 1077 includes a signal waveform switching unit 401, a first signal waveform transmission unit 403, and a second signal waveform transmission unit 405.

[0171] The signal waveform switching unit 401 switches between the first signal waveform and the second signal waveform for downlink communication to be transmitted according to predetermined conditions and circumstances.

[0172] When the downlink communication to be transmitted is a first signal waveform, the downlink communication is subjected to transmission processing by a first signal waveform transmission unit 403. When the downlink communication to be transmitted is a second signal waveform, the downlink communication is subjected to transmission processing by a second signal waveform transmission unit 405. The conditions and situations for switching in the signal waveform switching unit 401 will be described later.

[0173] The signal waveform switching unit 401 is also called a signal waveform control unit. In Fig. 10, the first signal waveform transmission unit 403 and the second signal waveform transmission unit 405 are depicted as separate processing units, but they may be configured as a single processing unit in which only part of the transmission process is switched.

[0174] 11 is a block diagram showing an example configuration of a first signal waveform transmission unit 403 according to an embodiment of the present disclosure. The first signal waveform transmission unit 403 performs transmission processing on a downlink channel and a signal transmitted by CP-OFDM as a signal waveform for uplink communication. The first signal waveform transmission unit 403 includes an S / P unit 4031, an IDFT (Inverse Discrete Fourier Transform) unit 4033, a P / S unit 4035, and a CP insertion unit 4037.

[0175] The S / P unit 4031 converts the input serial signal into a parallel signal of size M. Here, size M is determined depending on the size of the frequency domain resource used for downlink communication. The parallel signals of size M are input to the IDFT unit 4033 so as to correspond to a predetermined frequency domain.

[0176] The IDFT unit 4033 performs an inverse Fourier transform process on the parallel signals of size N. Here, if the size N is an exponent of 2, the Fourier transform process can be an inverse fast Fourier transform (IFFT) process. The P / S unit 4035 converts the parallel signals of size N into serial signals. The CP insertion unit 4037 inserts a predetermined CP into each OFDM symbol.

[0177] 12 is a block diagram showing an example configuration of the second signal waveform transmitter 405 according to an embodiment of the present disclosure. The second signal waveform transmitter 405 performs transmission processing on a downlink channel and a signal transmitted by, for example, DFT-S-OFDM as a signal waveform for downlink communication.

[0178] The second signal waveform transmission unit 405 includes a DFT unit 4051, an IDFT unit 4053, a P / S unit 4055, and a CP insertion unit 4057. The DFT unit 4051 performs DFT conversion to generate parallel signals of size M. Here, size M is determined depending on the size of the frequency domain resources used for downlink communication. The parallel signals of size M are input to the IDFT unit 4053 so as to correspond to a predetermined frequency domain.

[0179] The IDFT unit 4053 performs an inverse Fourier transform process on the parallel signals of size N. Here, if the size N is an exponent of 2, the Fourier transform process can be an IFFT process. The P / S unit 4055 converts the parallel signals of size N into serial signals. The CP insertion unit 4057 inserts a predetermined CP for each DFT-S-OFDM symbol.

[0180] 2-3. Example of the Configuration of the Terminal Device Next, a description will be given of the configuration of the terminal device 50. The terminal device 50 can also be called UE (User Equipment) 50.

[0181] The terminal device 50 is a communication device that wirelessly communicates with other communication devices such as the base station 20. The terminal device 50 is, for example, a mobile phone, a smart device (smartphone or tablet), a PDA (Personal Digital Assistant), or a personal computer. The terminal device 50 may also be a device such as a commercial camera equipped with a communication function, or a motorcycle or mobile broadcast vehicle equipped with a communication device such as an FPU (Field Pickup Unit). The terminal device 50 may also be an M2M (Machine to Machine) device or an IoT (Internet of Things) device.

[0182] The terminal device 50 may be capable of NOMA communication with the base station 20. Furthermore, the terminal device 50 may use an automatic repeat technique such as HARQ when communicating with the base station 20. The terminal device 50 may be capable of sidelink communication with other terminal devices 50. The terminal device 50 may also use an automatic repeat technique such as HARQ when performing sidelink communication. The terminal device 50 may also be capable of NOMA communication in communication (sidelink) with other terminal devices 50. Furthermore, the terminal device 50 may be capable of LPWA communication with other communication devices (e.g., the base station 20 and other terminal devices 50). Furthermore, the wireless communication used by the terminal device 50 may be wireless communication using millimeter waves. Furthermore, the wireless communication (including sidelink communication) used by the terminal device 50 may be wireless communication using radio waves, or wireless communication using infrared or visible light (optical wireless).

[0183] The terminal device 50 may also be mounted on a mobile device. The mobile device is a mobile wireless communication device. For example, the terminal device 50 may be a vehicle that moves on a road, such as an automobile, bus, truck, or motorcycle, a vehicle that moves on rails installed on a track, such as a train, or a wireless communication device mounted on the vehicle. The mobile device may be a mobile terminal, or a mobile device that moves on land (ground in the narrow sense), underground, on water, or underwater. The mobile device may also be a mobile device that moves within the atmosphere, such as a drone or helicopter, or a mobile device that moves outside the atmosphere, such as an artificial satellite.

[0184] The terminal device 50 may simultaneously connect to and communicate with a plurality of base stations 20 or a plurality of cells. For example, when one base station 20 supports a communication area through a plurality of cells (e.g., pCell, sCell), the plurality of cells can be bundled together to enable communication between the base station 20 and the terminal device 50 using carrier aggregation (CA) technology, dual connectivity (DC) technology, or multi-connectivity (MC) technology. Alternatively, the terminal device 50 can also communicate with a plurality of base stations 20 via cells of different base stations 20 using coordinated multi-point transmission and reception (CoMP) technology.

[0185] 13 is a block diagram showing an example configuration of a terminal device 50 according to an embodiment of the present disclosure. As shown in FIG. 13 , the terminal device 50 includes an upper layer processing unit 201, a control unit 203, a receiving unit 205, a transmitting unit 207, and a transmitting / receiving antenna 209.

[0186] The terminal device 50 may support one or more RATs. For example, the terminal device 50 may support both LTE and NR. In this case, some or all of the units included in the terminal device 50 may be configured individually according to the RAT. For example, the receiving unit 205 and the transmitting unit 207 are configured individually for LTE and NR. Also, in an NR cell, some or all of the units included in the terminal device 50 shown in FIG. 13 may be configured individually according to a parameter set related to a transmission signal. For example, in a certain NR cell, the radio receiving unit 2057 and the radio transmitting unit 2077 may be configured individually according to a parameter set related to a transmission signal.

[0187] (Upper Layer Processing Unit) Upper layer processing unit 201 outputs uplink data (transport blocks) to control unit 203. Upper layer processing unit 201 processes the medium access control layer, the integrated packet data protocol layer, the radio link control layer, and the radio resource control layer. Upper layer processing unit 201 also generates control information for controlling receiving unit 205 and transmitting unit 207, and outputs the control information to control unit 203.

[0188] The upper layer processing unit 201 performs processing and management related to RAT control, radio resource control, subframe configuration, scheduling control, and / or CSI reporting control. The processing and management in the upper layer processing unit 201 are performed based on predefined settings and / or settings based on control information configured or notified from the base station 20.

[0189] For example, the control information from the base station 20 includes an RRC parameter, a MAC control element, or DCI. Furthermore, the processing and management in the upper layer processing unit 201 may be performed separately depending on the RAT. For example, the upper layer processing unit 201 performs processing and management in LTE and processing and management in NR separately.

[0190] In the RAT control in the upper layer processing unit 201, management related to the RAT is performed. For example, in the RAT control, management related to LTE and / or management related to NR is performed. Management related to NR includes setting and processing of parameter sets related to transmission signals in NR cells.

[0191] The radio resource control in the upper layer processing unit 201 manages configuration information in the own device. The radio resource control in the upper layer processing unit 201 generates and / or manages uplink data (transport blocks), system information, RRC messages (RRC parameters), and / or MAC control elements (CEs).

[0192] The subframe configuration in the upper layer processing unit 201 manages subframe configurations in the base station 20 and / or in a base station different from the base station 20. The subframe configurations include uplink or downlink configurations for the subframes, subframe pattern configurations, uplink / downlink configurations, uplink reference UL-DL configurations, and / or downlink reference UL-DL configurations. Note that the subframe configuration in the upper layer processing unit 201 is also referred to as terminal subframe configurations.

[0193] In the scheduling control in the upper layer processing unit 201, control information for controlling the scheduling of the receiving unit 205 and the transmitting unit 207 is generated based on DCI (scheduling information) from the base station 20.

[0194] In the CSI reporting control in the upper layer processing unit 201, control is performed regarding reporting of CSI to the base station 20. For example, in the CSI reporting control, settings regarding CSI reference resources to be assumed for calculating CSI in the channel measurement unit 2059 are controlled. In the CSI reporting control, resources (timing) used for reporting CSI are controlled based on DCI and / or RRC parameters.

[0195] (Control Unit) The control unit 203 controls the receiving unit 205 and the transmitting unit 207 based on control information from the upper layer processing unit 201. The control unit 203 generates control information for the upper layer processing unit 201 and outputs it to the upper layer processing unit 201. The control unit 203 receives as input the decoded signal from the decoding unit 2051 and the channel estimation result from the channel measurement unit 2059. The control unit 203 outputs the signal to be coded to the coding unit 2071. The control unit 203 may also be used to control all or part of the terminal device 50.

[0196] Furthermore, the control unit 203 acquires information regarding a signal waveform to be used for downlink communication with the base station 20, from the base station 20 via the receiving unit 205, among single-carrier signals and multi-carrier signals. The information regarding the signal waveform to be used is information to be transmitted using a predetermined signal waveform (for example, a single-carrier signal). The control unit 203 controls the receiving unit 205 to perform downlink communication with the base station 20 using the signal waveform to be used.

[0197] (Receiving Unit) The receiving unit 205 receives signals transmitted from the base station 20 via the transmitting / receiving antenna 209 under the control of the control unit 203, and further performs reception processing such as separation, demodulation, and decoding, and outputs the processed information to the control unit 203. Note that the reception processing in the receiving unit 205 is performed based on a predetermined setting or a notification or setting from the base station 20. The receiving unit 205 includes a decoding unit 2051, a demodulating unit 2053, a demultiplexing unit 2055, a radio receiving unit 2057, and a channel measuring unit 2059.

[0198] (Radio Receiving Unit) The radio receiving unit 2057 performs the following operations on the uplink signal received via the transmitting / receiving antenna 209: converting to an intermediate frequency (down-converting), removing unnecessary frequency components, controlling the amplification level so that the signal level is maintained appropriately, quadrature demodulation based on the in-phase and quadrature components of the received signal, converting the analog signal to a digital signal, removing the guard interval, and / or extracting the signal in the frequency domain using a fast Fourier transform.

[0199] Here, the radio receiving unit 2057 according to this embodiment can support a plurality of uplink signal waveforms. Details of the radio receiving unit 2057 in the terminal device 50 that supports both the first signal waveform (multi-carrier signal) and the second signal waveform (single-carrier signal) will be described using Figures 14 to 16.

[0200] 14 is a block diagram showing an example configuration of the wireless receiving unit 2057 according to an embodiment of the present disclosure. The wireless receiving unit 2057 includes a signal waveform switching unit 301, a first signal waveform receiving unit 303, and a second signal waveform receiving unit 305.

[0201] The signal waveform switching unit 301 switches whether the received downlink communication has a first signal waveform or a second signal waveform, depending on predetermined conditions and situations. If the received downlink communication has the first signal waveform, the downlink communication is received and processed by the first signal waveform receiving unit 303. If the received downlink communication has the second signal waveform, the downlink communication is received and processed by the second signal waveform receiving unit 305.

[0202] In FIG. 14, the first signal waveform receiving unit 303 and the second signal waveform receiving unit 305 are shown as different processing units, but they may be configured as a single processing unit in which only part of the receiving processing is switched between.

[0203] 15 is a block diagram showing an example configuration of the first signal waveform receiving unit 303 according to an embodiment of the present disclosure. The first signal waveform receiving unit 303 performs reception processing on a downlink channel and a signal transmitted by CP-OFDM as a signal waveform for downlink communication. The first signal waveform receiving unit 303 includes a CP removal unit 3031, an S / P unit 3033, a DFT unit 3035, and a P / S unit 3037.

[0204] The CP removal unit 3031 removes a cyclic prefix (CP) added to the received downlink communication. The S / P unit 3033 converts the input serial signal into a parallel signal of size N. The DFT unit 3035 performs Fourier transform processing. Here, if the size N is an exponent of 2, the Fourier transform processing can be FFT processing.

[0205] The P / S unit 3037 converts the input parallel signal of size M into a serial signal. Here, the P / S unit 3037 receives as input a downlink communication signal transmitted by a terminal device 50 that performs reception processing. The size M is determined depending on the size of the frequency domain resource used for downlink communication.

[0206] 16 is a block diagram showing an example configuration of the second signal waveform receiving unit 305 according to an embodiment of the present disclosure. The second signal waveform receiving unit 305 performs reception processing on a downlink channel and a signal transmitted by, for example, DFT-S-OFDM as a signal waveform for downlink communication. The second signal waveform receiving unit 305 includes a CP removal unit 3051, an S / P unit 3053, a DFT unit 3055, and an IDFT unit 3057.

[0207] The CP removal unit 3051 removes the CP added to the received downlink communication. The S / P unit 3053 converts the input serial signal into a parallel signal of size N. The DFT unit 3055 performs Fourier transform processing. Here, if the size N is an exponent of 2, the Fourier transform processing can be FFT processing.

[0208] The IDFT unit 3057 performs inverse Fourier transform processing on an input signal of size M. Here, a downlink communication signal transmitted by the terminal device 50 that performs reception processing is input to the IDFT unit 3057. Furthermore, the size M is determined depending on the size of the frequency domain resource used for downlink communication.

[0209] 13 , the demultiplexing unit 2055 separates downlink channels such as PHICH, PDCCH, EPDCCH, or PDSCH, a downlink synchronization signal, and / or a downlink reference signal from the signal input from the radio receiving unit 2057. The demultiplexing unit 2055 outputs the downlink reference signal to the channel measurement unit 2059. The demultiplexing unit 2055 performs propagation path compensation for the downlink channel based on the propagation path estimate input from the channel measurement unit 2059.

[0210] (Demodulation Unit) The demodulation unit 2053 demodulates the received signal using a modulation method such as BPSK, π / 2BPSK, QPSK, 16QAM, 64QAM, 256QAM, etc. for the modulation symbols of the downlink channel. The demodulation unit 2053 separates and demodulates the MIMO-multiplexed downlink channels.

[0211] (Decoding Unit) The decoding unit 2051 performs decoding processing on the coded bits of the demodulated downlink channel. The decoded downlink data and / or downlink control information is output to the control unit 203. The decoding unit 2051 performs decoding processing on the PDSCH for each transport block.

[0212] (Channel Measurement Unit) The channel measurement unit 2059 measures the propagation path estimate and / or channel quality from the downlink reference signal input from the demultiplexing unit 2055 and outputs the results to the demultiplexing unit 2055 and / or the control unit 203.

[0213] The downlink reference signal used for measurement by the channel measurement unit 2059 may be determined based on at least the transmission mode set by the RRC parameters and / or other RRC parameters.

[0214] For example, DL-DMRS measures an estimated value of a propagation path for performing propagation path compensation for a PDSCH or an EPDCCH. CRS measures an estimated value of a propagation path for performing propagation path compensation for a PDCCH or a PDSCH and / or a downlink channel for reporting CSI. CSI-RS measures a downlink channel for reporting CSI.

[0215] The channel measurement unit 2059 calculates RSRP (Reference Signal Received Power) and / or RSRQ (Reference Signal Received Quality) based on the CRS, CSI-RS, or detected signal, and outputs it to the upper layer processing unit 201.

[0216] (Transmitting Unit) The transmitting unit 207 performs transmission processing such as coding, modulation, and multiplexing on the uplink control information and uplink data input from the upper layer processing unit 201, under the control of the control unit 203. For example, the transmitting unit 207 generates and multiplexes an uplink channel such as a PUSCH or a PUCCH and / or an uplink reference signal to generate a transmission signal.

[0217] The transmission processing in the transmitting unit 207 is performed based on a predetermined setting or a setting or notification from the base station 20. The transmitting unit 207 includes an encoding unit 2071, a modulation unit 2073, a multiplexing unit 2075, a radio transmitting unit 2077, and an uplink reference signal generating unit 2079.

[0218] (Encoding unit) The encoding unit 2071 encodes the HARQ indicator (HARQ-ACK), uplink control information, and uplink data input from the control unit 203 using a predetermined encoding method such as block coding, convolutional coding, turbo coding, etc.

[0219] (Modulation Unit) The modulation unit 2073 modulates the coded bits input from the coding unit 2071 using a predetermined modulation method such as BPSK, π / 2BPSK, QPSK, 16QAM, 64QAM, or 256QAM.

[0220] (Uplink Reference Signal Generator) The uplink reference signal generator 2079 generates an uplink reference signal based on the RRC parameters set in the terminal device 50 and the like.

[0221] (Multiplexing Unit) The multiplexing unit 2075 multiplexes the modulation symbols of each channel and the uplink reference signal, and arranges the multiplexed symbols in predetermined resource elements.

[0222] (Radio Transmission Unit) The radio transmission unit 2077 converts the signal from the multiplexing unit 2075 into a time domain signal by inverse fast Fourier transform, adds a guard interval, generates a baseband digital signal, converts it into an analog signal, and performs quadrature modulation. The radio transmission unit 2077 performs processes such as converting an intermediate frequency signal into a high frequency signal (up-conversion), removing unnecessary frequency components, and amplifying power to generate a transmission signal. The transmission signal output by the radio transmission unit 2077 is transmitted from the transmission / reception antenna 209.

[0223] <<3. Operation of the Communication System>> Here, an example of an operation related to measurements performed in the communication system SYS1 and an example of an operation related to handover will be described.

[0224] <3-1. Notification of Waveform Information> The base station 20 of the neighboring cell or the target cell (target base station) can notify the base station 20 of the serving cell (serving base station) of waveform information related to one or more signal waveforms in downlink communication. For example, the control unit 103 of the base station 20 of the neighboring cell or the target cell notifies the base station 20 of the serving cell of the waveform information.

[0225] Hereinafter, when distinguishing from the waveform information included in the measurement information, the waveform information notified by the target base station to the serving base station will be referred to as first waveform information, and the waveform information included in the measurement information will be referred to as second waveform information. When there is no need to distinguish between them, they will simply be referred to as waveform information.

[0226] (First Waveform Information) The waveform information of the adjacent cell or the target cell includes information on the first signal waveform and / or the second signal waveform.

[0227] The first signal waveform is a multi-carrier signal waveform, and the second signal waveform is a single-carrier signal waveform.

[0228] The first waveform information includes at least one of the following information: - Information on Enable or Disable of the signal waveform - Information on Capability of the signal waveform - Information on the resource to which the signal waveform is applied

[0229] (Information Regarding Enable or Disable) Information regarding enable or disable of signal waveforms includes at least one of information regarding enable or disable of a first signal waveform and information regarding enable or disable of a second signal waveform.

[0230] If the first waveform information includes information indicating that the first signal waveform is enabled, the first signal waveform is ２ That is, the first signal waveform is used for downlink communication between the base station 20 and the base station 21. ２When the first waveform information includes information indicating that the first signal waveform is disabled, the first signal waveform is used by the base station 20. ２ That is, the first signal waveform is not used for downlink communication of the base station 20. ２ This is not the signal waveform used.

[0231] If the first waveform information includes information indicating that the second signal waveform is enabled, the second signal waveform is ２ That is, the second signal waveform is used for downlink communication of the base station 20. ２ When the first waveform information includes information indicating that the second signal waveform is disabled, the second signal waveform is used by the base station 20. ２ That is, the second signal waveform is not used for downlink communication of the base station 20. ２ This is not the signal waveform used.

[0232] (Information Regarding Capability) The information regarding the capability of the signal waveform includes at least one of information regarding the capability of the first signal waveform and information regarding the capability of the second signal waveform.

[0233] (Information Regarding Resources) Information regarding resources to which signal waveforms are applied includes at least one of information regarding resources to which a first signal waveform is applied and information regarding resources to which a second signal waveform is applied.

[0234] (Information on Resources to Which the First Signal Waveform is Applied) Information on resources to which the first signal waveform is applied includes, for example, at least one of the following pieces of information on resources: - Information on time resources - Information on frequency resources - Information on spatial resources - Information on physical channels

[0235] (Time Resources) Examples of time resources include the following resources. However, the resources listed here are only examples. Resources other than those listed here may be included in the information on resources to which the first signal waveform is applied, as long as they are time-related resources.

[0236] -Symbol -Sub-Symbol -Slot -Mini-Slot -Non-Slot -Subslot -Subframe -Frame -PRACH occasion

[0237] (Frequency Resources) Examples of frequency resources include the following resources. However, the resources listed here are only examples. Resources other than those listed here may be included in the information on resources to which the first signal waveform is applied, as long as they are frequency-related resources.

[0238] - Resource Element (including REG, CCE, and CORESET) - Resource Block - Bandwidth Part - Component Carrier - PRACH occasion - Subcarrier Spacing

[0239] (Spatial Resources) Examples of spatial resources include the following resources. However, the resources listed here are only examples. Resources other than those listed here may be included in the information on resources to which the first signal waveform is applied, as long as they are spatial resources.

[0240] -Physical Cell ID -Beam ID -Antenna Port -Location ID -Ephemeris information

[0241] (Physical Channels) Examples of physical channels include the following channels. However, the channels listed here are merely examples. As long as they are physical channels, channels other than those listed here may be included in the information regarding the resource to which the first signal waveform is applied.

[0242] -Primary Synchronization signal -Secondary Synchronization signal -PBCH -PDSCH -PDCCH -PUSCH -PUCCH -PSSCH -PSCCH -DMRS -PTRS -PRS -SRS

[0243] (Information on Resources to Which Second Signal Waveform is Applied) Information on resources to which the second signal waveform is applied includes, for example, at least one of the following pieces of information on resources: - Information on time resources - Information on frequency resources - Information on spatial resources - Information on physical channels

[0244] (Temporal Resources) Examples of temporal resources include the following resources. However, the resources listed here are merely examples. Resources other than those listed here may be included in the information regarding resources to which the second signal waveform is applied, as long as they are time-related resources.

[0245] -Symbol -Sub-Symbol -Slot -Mini-Slot -Non-Slot -Subslot -Subframe -Frame -PRACH occasion

[0246] (Frequency Resources) Examples of frequency resources include the following resources. However, the resources listed here are only examples. Resources other than those listed here may be included in the information on resources to which the second signal waveform is applied, as long as they are frequency-related resources.

[0247] - Resource Element (including REG, CCE, and CORESET) - Resource Block - Bandwidth Part - Component Carrier - PRACH occasion - Subcarrier Spacing

[0248] (Spatial Resources) Examples of spatial resources include the following resources. However, the resources listed here are only examples. Resources other than those listed here may be included in the information on resources to which the second signal waveform is applied, as long as they are spatial resources.

[0249] -Physical Cell ID -Beam ID -Antenna Port -Location ID -Ephemeris information

[0250] (Physical Channels) Examples of physical channels include the following channels. However, the channels listed here are merely examples. As long as they are physical channels, channels other than those listed here may be included in the information regarding the resources to which the second signal waveform is applied.

[0251] -Primary Synchronization signal -Secondary Synchronization signal -PBCH -PDSCH -PDCCH -PUSCH -PUCCH -PSSCH -PSCCH -DMRS -PTRS -PRS -SRS

[0252] (Information about Transform Precoding) Waveform information of a neighboring cell or a target cell may include information about Transform Precoding.

[0253] The information related to Transform precoding includes at least one of the following information: - Information related to Enable or Disable of Transform precoding - Information related to Capability of Transform precoding - Information related to resources for which Transform precoding is enabled or disabled

[0254] (Information about Enable or Disable) It is assumed that information about Transform precoding is included in the information about Transform precoding. In this case, the base station 20 ２ transmits a signal to which Transform precoding has been applied, i.e., a signal having a second signal waveform. ２ On the other hand, in this case, the base station 20 ２ does not use the first signal waveform for downlink communication.

[0255] It is assumed that the information about transform precoding is included in the information about transform precoding. In this case, the base station 20 ２ transmits a signal to which transform precoding has not been applied, i.e., a signal having a first signal waveform. ２ On the other hand, in this case, the base station 20 ２ does not use the second signal waveform for downlink communication.

[0256] (Information Regarding Resources) The information regarding resources for which Transform precoding is enabled is the same as the information regarding resources for which the second signal waveform is applied, and therefore its description will be omitted. Also, the information regarding resources for which Transform precoding is disabled is the same as the information regarding resources for which the first signal waveform is applied, and therefore its description will be omitted.

[0257] <3-2. Notification of Measurement Information> The base station 20 of the serving cell may notify the terminal device 50 of measurement information related to measurements in downlink communication (measurements of downlink communication quality). For example, the control unit 103 of the base station 20 of the serving cell notifies the terminal device 50 of the measurement information.

[0258] The measurement information includes at least one of the following information: - second waveform information - implementation information

[0259] (Second Waveform Information) The waveform information included in the measurement information is the waveform information of the target base station (base station 20) described above. ２ ) waveform information (first waveform information) of the serving base station (base station 20 １ ) waveform information.

[0260] That is, the serving base station may include at least a part of the first waveform information acquired from the target base station in the measurement information and notify the terminal device 50. Furthermore, the serving base station may include waveform information related to the signal waveform that it uses in the measurement information and notify the terminal device 50.

[0261] The details of the waveform information of the serving base station are the same as the first waveform information (the same as the first waveform information with the target base station replaced with the serving base station), so a description thereof will be omitted here.

[0262] (Implementation Information) The measurement information includes implementation information for the terminal device 50 to implement measurements. The implementation information includes, for example, implementation timing information. The implementation timing information is, for example, information related to the timing of implementing measurements. The implementation timing information may include, for example, at least one of a measurement implementation request, implementation timing, implementation period, and implementation trigger.

[0263] In addition, if the timing at which the terminal device 50 performs measurements is determined in advance, transmission of the measurement timing information, in other words, transmission of the measurement information may be omitted.

[0264] Furthermore, each piece of information included in the measurement information (for example, the second waveform information and the implementation information) may be notified from the serving base station to the terminal device 50 at the same timing or at different timings.

[0265] For example, the waveform information of the target base station and the waveform information of the serving base station may be notified at the same time (e.g., as the same piece of information), or the waveform information of the target base station and the waveform information of the serving base station may be notified at different times (e.g., as separate pieces of information).

[0266] For example, information on whether to enable or disable the signal waveform of the waveform information of the target base station, information on the capability of the signal waveform, and information on the resource to which the signal waveform is applied may be notified at the same timing, or each of these pieces of information may be notified at a different timing.

[0267] <3-3. Measurement> For example, measurements by the terminal device 50 may be performed periodically or aperiodic. When measurements are performed periodically, the terminal device 50 performs measurements at a predetermined or notified timing (or cycle). The timing at which measurements are performed may be a combination of multiple cycles. Alternatively, measurements may be performed constantly.

[0268] If the measurement is performed aperiodic, the performance information may include a measurement performance request or performance trigger.

[0269] For example, the terminal device 50 performs measurement at the timing when it receives an implementation request from the serving base station. Note that, when the terminal device 50 performs measurement at the timing when it receives second waveform information, the second waveform information functions as a measurement implementation request.

[0270] In this case, for example, when the terminal device 50 acquires waveform information (first waveform information) of the target base station, the terminal device 50 may measure downlink communication with the target base station at the timing of acquisition. Similarly, when the terminal device 50 acquires waveform information of the serving base station, the terminal device 50 may measure downlink communication with the serving base station at the timing of acquisition.

[0271] Furthermore, for example, the terminal device 50 performs measurements according to a predetermined or notified implementation trigger. The terminal device 50 performs measurements at a timing when the implementation trigger is satisfied. The implementation trigger includes, for example, at least one of the following triggers: - When a predetermined or notified time (time) is reached - When the reception quality falls below a certain level - When the moving speed of the terminal device 50 increases - When the terminal device 50 starts moving

[0272] The terminal device 50 measures, for example, the quality of a downlink signal (e.g., a reference signal). For example, the terminal device 50 measures the communication quality of at least one of a downlink signal having a first signal waveform and a downlink signal having a second signal waveform based on the measurement information. The terminal device 50 measures the downlink communication quality using a downlink signal having a used signal waveform.

[0273] For example, the communication quality of the downlink signal may be at least one of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RSSI (Received Signal Strength Indicator), and SINR (Signal to Interference plus Noise Ratio).

[0274] It is considered that the communication quality measured for each signal waveform differs when the signal waveform of the downlink signal differs. Therefore, as described above, the terminal device 50 may measure the communication quality of the downlink signal for each signal waveform.

[0275] That is, the base station 20 transmits a first signal having a first signal waveform, the first signal being used for the measurement of downlink communication, and a second signal having a second signal waveform, the second signal being used for the measurement of downlink communication.

[0276] The first signal and the second signal are synchronization signal blocks. The base station 20 may transmit, for example, an independent SSB (SS (Synchronization Signal) / PBCH (Physical Broadcast Channel) Block) for each signal waveform. For example, the base station 20 may transmit a PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), PBCH, or SSB for multi-carrier, and a PSS, SSS, PBCH, or SSB for single-carrier.

[0277] Alternatively, the first signal and the second signal are reference signals for downlink signals. For example, the base station 20 may transmit a Channel State Information-Reference Signal (CSI-RS) for each signal waveform. For example, the base station 20 may transmit a CSI-RS for multi-carrier and a CSI-RS for single-carrier.

[0278] In this case, the base station 20 may transmit the same (common) PSS, SSS, PBCH, or SSB using a plurality of signal waveforms.

[0279] <3-4. Measurement Report> For example, the measurement result by the terminal device 50 is reported (feedback) to the serving base station as a measurement report. The terminal device 50 reports the measurement result of the downlink signal to the serving base station. The terminal device 50 reports at least one of the measurement result of the downlink signal of the first signal waveform and the measurement result of the downlink signal of the second signal waveform.

[0280] For example, if the second waveform information described above includes information related to Transform precoding, the terminal device 50 reports at least one of the measurement results when Transform precoding is enabled and the measurement results when Transform precoding is disabled.

[0281] For example, the terminal device 50 reports at least one of the following information as a measurement result to the serving base station: - SS-RSRP - CSI-RSRP - SS-RSRQ - CSI-RSRQ - SS-RSSI - CSI-RSSI - SS-SINR - CSI-SINR

[0282] In addition, the terminal device 50 may report the measurement results of the communication quality of downlink signals of multiple signal waveforms to the serving base station as a single measurement report, or may report the results to the serving base station as individual measurement reports for each signal waveform.

[0283] The terminal device 50 executes the measurement report, for example, periodically or aperiodic (at a timing according to a trigger).

[0284] When the measurement report is performed periodically, the terminal device 50 performs the measurement report at a predetermined timing (or period).

[0285] When a measurement report is performed aperiodic (event trigger), the terminal device 50 performs a measurement report at the timing when a measurement report execution request is received or when a report execution trigger is satisfied.

[0286] For example, the terminal device 50 performs a measurement report when it receives a measurement report request from the serving base station. This measurement report request may be the same as the measurement request.

[0287] That is, when the terminal device 50 receives a request to perform measurements from the serving base station, it performs measurements and notifies the serving base station of a measurement report.

[0288] Furthermore, for example, the terminal device 50 executes a measurement report in accordance with a predetermined or notified report execution trigger. The terminal device 50 executes a measurement report at a timing when the report execution trigger is satisfied.

[0289] A report execution trigger may be when the communication quality (e.g., RSRP) of a downlink signal transmitted from a target base station exceeds a threshold. Hereinafter, the communication quality of a downlink signal transmitted from a target base station is also referred to as target communication quality.

[0290] For example, if the target communication quality of the measured first signal waveform (or a signal waveform for which transform precoding is disabled) is equal to or higher than a threshold, the terminal device 50 reports the measurement result to the serving base station.

[0291] Furthermore, for example, if the target communication quality of the measured second signal waveform (or a signal waveform for which Transform precoding is enabled) is equal to or higher than a threshold, the terminal device 50 reports the measurement result to the serving base station.

[0292] A trigger for reporting is when the communication quality (e.g., RSRP) of a downlink signal transmitted from a serving base station exceeds a threshold. Hereinafter, the communication quality of a downlink signal transmitted from a serving base station is also referred to as serving communication quality.

[0293] For example, if the serving communication quality of the measured first signal waveform (or a signal waveform for which transform precoding is disabled) is equal to or higher than a threshold, the terminal device 50 reports the measurement result to the serving base station.

[0294] Furthermore, for example, if the serving communication quality of the measured second signal waveform (or the signal waveform for which Transform precoding is enabled) is equal to or higher than a threshold, the terminal device 50 reports the measurement result to the serving base station.

[0295] Examples of triggers for reporting include triggers based on the difference between the target communication quality of a first signal waveform (or a signal waveform in which Transform precoding is disabled) and the target communication quality of a second signal waveform (or a signal waveform in which Transform precoding is enabled).

[0296] For example, if the target communication quality of the measured first signal waveform is greater than or equal to the offset or less than the target communication quality of the measured second signal waveform, the terminal device 50 reports the measurement result to the serving base station.

[0297] For example, if the target communication quality of the measured second signal waveform is greater than or equal to the offset or less than the target communication quality of the measured first signal waveform, the terminal device 50 reports the measurement result to the serving base station.

[0298] For example, if the target communication quality of the measured first signal waveform is better (or worse) than the target communication quality of the measured second signal waveform, the terminal device 50 reports the measurement result to the serving base station.

[0299] Examples of triggers for reporting include triggers corresponding to fluctuations in the target communication quality of a first signal waveform (or a signal waveform in which Transform precoding is disabled) and triggers corresponding to fluctuations in the target communication quality of a second signal waveform (or a signal waveform in which Transform precoding is enabled).

[0300] For example, the terminal device 50 reports the measurement results to the serving base station when the target communication quality of the first signal waveform becomes worse than a first threshold and / or when the target communication quality of the second signal waveform becomes better than a second threshold.

[0301] For example, a trigger for executing a report may be a trigger according to the difference between the serving communication quality and the target communication quality.

[0302] For example, a trigger for reporting may be when the Serving communication quality of the first signal waveform (or the signal waveform in which Transform precoding is Disabled) becomes equal to or less than the Offset from the Target communication quality of at least one of the first signal waveform and the second signal waveform (or the signal waveform in which Transform precoding is Enable).

[0303] Alternatively, the report execution trigger may be when the Serving communication quality of the second signal waveform becomes equal to or less than the Offset from the Target communication quality of at least one of the first signal waveform and the second signal waveform.

[0304] Alternatively, the report execution trigger may be when the Serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or lower than the Offset from the Target communication quality of the first signal waveform.

[0305] Alternatively, the report execution trigger may be when the Serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or lower than the Offset from the Target communication quality of the second signal waveform.

[0306] Here, when the terminal device 50 reports communication quality for multiple signal waveforms to the serving base station, the trigger may be satisfied for multiple signal waveforms. In this case, the terminal device 50 may notify the serving base station of a measurement report for all signal waveforms for which measurements have been performed, for example.

[0307] Alternatively, the terminal device 50 may perform a measurement report according to, for example, the priority of the signal waveform. For example, if a first signal waveform has a higher priority than a second signal waveform, the terminal device 50 notifies the serving base station of a measurement report of the downlink signal of the first signal waveform.

[0308] This priority may be determined statically based on, for example, a standard, or may be determined semi-statically based on a notification from a serving base station, etc. For example, when the priority is determined semi-statically, the serving base station sets in advance in the terminal device 50 which signal waveform measurement report is to be given priority.

[0309] Furthermore, the report execution trigger is not limited to the trigger related to the signal waveform described above.

[0310] For example, a report execution trigger may be when the communication quality (e.g., RSRP) of a neighboring cell (e.g., target cell) becomes higher than the communication quality (e.g., RSRP) of the cell to which the neighboring cell belongs (e.g., serving cell) by an offset or more.

[0311] For example, a trigger for reporting may be when the communication quality of an adjacent cell becomes better than the communication quality of the cell to which the cell belongs.

[0312] For example, a trigger for reporting may be when the communication quality of the cell to which the mobile station belongs becomes worse than a first threshold value and the communication quality of the adjacent cell becomes better than a second threshold value.

[0313] For example, a trigger for reporting may be when the quality of a reference signal (e.g., CSI-RS) resource becomes better than a threshold.

[0314] For example, a report execution trigger may be when the moving speed of the terminal device 50 is equal to or greater than a threshold. For example, a report execution trigger may be when the moving speed of the terminal device 50 is equal to or less than a threshold.

[0315] The terminal device 50 may determine the signal waveform to be measured based on the measurement information. Alternatively, if a default signal waveform to be measured is defined, the terminal device 50 may determine, for example, based on the measurement information, whether to measure and report a signal waveform that is not defined as the default.

[0316] For example, it is assumed that the first signal waveform is defined as the default signal waveform for measuring the target cell. In this case, the terminal device 50 determines whether to measure the downlink signal of the second signal waveform in the target cell depending on whether the measurement information includes waveform information on the second signal waveform of the target cell. When the measurement information includes waveform information on the second signal waveform of the target cell, the terminal device 50 performs measurement of the downlink signal of the second signal waveform in the target cell.

[0317] Alternatively, the terminal device 50 may determine whether to measure the downlink signal having the second signal waveform in the target cell depending on whether the measurement information includes waveform information of the target cell. When the measurement information includes waveform information of the target cell, the terminal device 50 performs measurement of the downlink signal having the second signal waveform in the target cell.

[0318] For example, the serving base station may determine whether to cause the terminal device 50 to perform measurements of the downlink signal of the second signal waveform in the target cell, depending on whether the serving base station has acquired first waveform information (or first waveform information related to the second signal waveform) from the target base station.

[0319] For example, if the serving base station does not acquire the first waveform information from the target base station, the serving base station determines not to cause the terminal device 50 to measure the downlink signal of the second signal waveform in the target cell. In this case, for example, the serving base station notifies the terminal device 50 of measurement information that does not include the first waveform information (or the first waveform information related to the second signal waveform).

[0320] For example, it is assumed that the second signal waveform is defined as the default signal waveform for measuring the target cell. In this case, the terminal device 50 determines whether to measure the downlink signal of the first signal waveform in the target cell depending on whether the measurement information includes waveform information on the first signal waveform of the target cell. When the measurement information includes waveform information on the first signal waveform of the target cell, the terminal device 50 performs measurement of the downlink signal of the first signal waveform in the target cell.

[0321] Alternatively, the terminal device 50 may determine whether to measure the downlink signal of the first signal waveform in the target cell depending on whether waveform information of the target cell is included in the measurement information. When the waveform information of the target cell is included in the measurement information, the terminal device 50 performs measurement of the downlink signal of the first signal waveform in the target cell.

[0322] For example, the serving base station may determine whether to cause the terminal device 50 to perform measurement of the downlink signal of the first signal waveform in the target cell, depending on whether the serving base station has acquired first waveform information (or first waveform information related to the first signal waveform) from the target base station.

[0323] For example, if the serving base station does not acquire the first waveform information (or the first waveform information related to the first signal waveform) from the target base station, the serving base station decides not to cause the terminal device 50 to measure the downlink signal of the first signal waveform in the target cell. In this case, for example, the serving base station notifies the terminal device 50 of measurement information that does not include the first waveform information (or the first waveform information related to the first signal waveform).

[0324] The "target cell" described herein may be appropriately interpreted as a "serving cell." The first signal waveform may be appropriately interpreted as a signal waveform that disables transform precoding. The second signal waveform may be appropriately interpreted as a signal waveform that enables transform precoding.

[0325] <3-5. Handover Determination> The serving base station determines whether or not to perform handover of the terminal device 50 based on the measurement report from the terminal device 50 .

[0326] For example, the serving base station determines to perform a handover when the target communication quality of the first signal waveform is equal to or higher than a threshold, and the serving base station determines to perform a handover when the target communication quality of the second signal waveform is equal to or higher than a threshold.

[0327] For example, the serving base station determines to perform a handover when the serving communication quality of the first signal waveform falls below a threshold, and also determines to perform a handover when the serving communication quality of the second signal waveform falls below a threshold.

[0328] For example, the serving base station determines to perform handover when the target communication quality of the first signal waveform is equal to or higher than the offset or lower than the target communication quality of the second signal waveform.

[0329] For example, the serving base station determines to perform handover when the target communication quality of the second signal waveform is equal to or higher than the offset or lower than the target communication quality of the first signal waveform.

[0330] For example, the serving base station determines to perform handover when the target communication quality of the first signal waveform is better (or worse) than the target communication quality of the second signal waveform.

[0331] The handover determination criteria include a trigger according to a fluctuation in the target communication quality of the first signal waveform and a fluctuation in the target communication quality of the second signal waveform.

[0332] For example, the serving base station determines to perform a handover when the target communication quality of the first signal waveform becomes worse than a first threshold and / or when the target communication quality of the second signal waveform becomes better than a second threshold.

[0333] For example, the handover decision criterion may be based on the difference between the serving communication quality and the target communication quality.

[0334] For example, the serving base station determines to perform handover when the serving communication quality of the first signal waveform (or the signal waveform for which Transform precoding is Disabled) becomes equal to or lower than the offset from the target communication quality of at least one of the first signal waveform and the second signal waveform (or the signal waveform for which Transform precoding is Enable).

[0335] Alternatively, the serving base station determines to perform handover when the serving communication quality of the second signal waveform becomes equal to or lower than the offset from the target communication quality of at least one of the first signal waveform and the second signal waveform.

[0336] Alternatively, the serving base station determines to perform handover when the serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or lower than the offset from the target communication quality of the first signal waveform.

[0337] Alternatively, the serving base station determines to perform handover when the serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or lower than the offset from the target communication quality of the second signal waveform.

[0338] In this way, the serving base station determines whether to perform a handover based on at least one of the serving communication quality of the first signal waveform, the serving communication quality of the second signal waveform, the target communication quality of the first signal waveform, and the target communication quality of the second signal waveform.

[0339] <3-6. Instruction Information> The serving base station that has decided to perform handover notifies the terminal device 50 of instruction information (for example, a Handover command).

[0340] The instruction information (an example of handover information) includes at least one of the following information: Waveform information of the target cell Information about the handover procedure Measurement information Information about the measurement report

[0341] The waveform information of the target cell includes at least a part of the above-described first waveform information. The serving base station may use the first waveform information acquired from the target base station for measurement as the waveform information of the target cell. Alternatively, the serving base station may acquire the first waveform information from the target base station prior to notifying the instruction information.

[0342] Furthermore, the waveform information of the target cell may include information indicating which signal waveform will be used to perform the handover procedure (e.g., a random access procedure). For example, the serving base station may include first waveform information related to the signal waveform used for the handover procedure in the waveform information of the target cell, thereby indicating to the terminal device 50 which signal waveform will be used to perform the handover procedure.

[0343] The information related to the handover procedure includes at least one of the following information: - PRACH transmission resource of the target cell - PRACH transmission preamble sequence of the target cell - Cell ID of the target cell - Uplink / Downlink carrier frequency of the target cell - Bandwidth of the target cell - Terminal-specific ID after handover (C-RNTI) - Radio resource configuration after handover - Conditions for updating the information set related to handover - Trigger information for performing handover - Timing advance information of the target cell - SSB index of the target cell - Information related to transmission weight - Information related to 2-STEP initial access

[0344] The measurement information may be the same as the measurement information that the serving base station notifies to the terminal device 50 for the above-described measurement. Alternatively, for example, the measurement information here may be the above-described implementation information.

[0345] Furthermore, the information related to the measurement report includes information for the terminal device 50 to perform a measurement report. The information related to the measurement report may include information related to the priority of the signal waveform to be reported, information related to a report execution trigger, and the like.

[0346] The terminal device 50 that has acquired the instruction information executes a handover procedure from the serving base station to the target base station based on the acquired instruction information. For example, the terminal device 50 executes the handover procedure using a signal waveform specified by waveform information of the target cell included in the instruction information.

[0347] Here, the instruction information is a Handover command, that is, the Handover command includes waveform information of the Target cell, but the instruction information does not have to be the Handover command itself. For example, the instruction information may include the Handover command and waveform information of the Target cell.

[0348] In this way, the Handover command and the waveform information of the Target cell may be different information (information transmitted separately). The waveform information of the Target cell may be notified to the terminal device 50 at the same timing as the Handover command, or may be notified at a different timing (for example, before the Handover command).

[0349] Alternatively, if the waveform information of the target cell is the same as the waveform information included in the measurement information for measurement, notification of the waveform information of the target cell may be omitted. In this case, the terminal device 50 performs handover based on the waveform information included in the measurement information.

[0350] In this case, the measurement information included in the instruction information may be included in the Handover command or the waveform information of the Target cell.

[0351] Alternatively, the instruction information may include the measurement information separately from the Handover command and the waveform information of the Target cell. In this case, the measurement information may be notified to the terminal device 50 at the same timing as at least one of the Handover command and the waveform information of the Target cell, or may be notified at a different timing.

[0352] Note that the measurement information here (measurement information included in the instruction information) can be read as information related to the measurement report included in the instruction information.

[0353] <3-7. Conditional Handover> When a conditional handover is performed in the communication system SYS1, the serving base station notifies the terminal device 50 of information on the conditional handover (an example of conditional handover information) as instruction information.

[0354] The information related to the conditional handover includes at least one of the following information: - Waveform information of neighboring cells - Procedure information related to the conditional handover procedure - Trigger information related to the trigger of the conditional handover - Detachment information related to the execution of detachment from the serving base station - Measurement information - Information related to the measurement report

[0355] The waveform information of the neighboring cell includes information similar to the waveform information of the target cell described above. The waveform information of the neighboring cell includes first waveform information of the base station 20 that is a target cell candidate. Here, there may be one or more neighboring cells. In other words, the waveform information of the neighboring cell includes first waveform information of one or more base stations 20 that are target cell candidates.

[0356] The procedure information regarding the conditional handover procedure includes, for example, at least one of the following information: - PRACH transmission resource of the target cell candidate - PRACH transmission preamble sequence of the target cell candidate - Cell ID of the target cell candidate - Uplink / Downlink carrier frequency of the target cell candidate - Bandwidth of the target cell candidate - Terminal unique ID after handover (C-RNTI) - Radio resource configuration after handover - Conditions for updating the information set related to handover - Trigger information for performing handover - Timing advance information of the target cell candidate - SSB index of the target cell candidate - Information related to transmission weight - Information related to 2-STEP initial access

[0357] The trigger information regarding the trigger of Conditional Handover includes at least one of information regarding a waveform execution trigger regarding the trigger of Conditional Handover related to waveform information, and information regarding the execution trigger.

[0358] An example of a waveform execution trigger is when the communication quality (target communication quality, for example, RSRP) of a downlink signal transmitted from a target base station becomes equal to or greater than a threshold.

[0359] For example, the terminal device 50 executes Conditional Handover when the Target communication quality of the measured first signal waveform (or a signal waveform for which Transform precoding is Disabled) is equal to or higher than a threshold.

[0360] Furthermore, for example, the terminal device 50 executes Conditional Handover when the Target communication quality of the measured second signal waveform (or the signal waveform for which Transform precoding is enabled) is equal to or higher than a threshold.

[0361] An example of a waveform execution trigger is when the communication quality (serving communication quality, for example, RSRP) of a downlink signal transmitted from a serving base station becomes equal to or greater than a threshold.

[0362] For example, the terminal device 50 executes Conditional Handover when the Serving communication quality of the measured first signal waveform (or a signal waveform for which Transform precoding is Disabled) is equal to or higher than a threshold.

[0363] Furthermore, for example, the terminal device 50 executes Conditional Handover when the Serving communication quality of the measured second signal waveform (or the signal waveform for which Transform precoding is enabled) is equal to or higher than a threshold.

[0364] Examples of waveform implementation triggers include triggers based on the difference between the target communication quality of a first signal waveform (or a signal waveform in which Transform precoding is disabled) and the target communication quality of a second signal waveform (or a signal waveform in which Transform precoding is enabled).

[0365] For example, the terminal device 50 executes conditional handover when the target communication quality of the measured first signal waveform is equal to or greater than the offset or less than the target communication quality of the measured second signal waveform.

[0366] For example, the terminal device 50 executes conditional handover when the target communication quality of the measured second signal waveform is equal to or higher than the offset or lower than the target communication quality of the measured first signal waveform.

[0367] For example, if the target communication quality of the measured first signal waveform is better (or worse) than the target communication quality of the measured second signal waveform, the terminal device 50 executes conditional handover.

[0368] Examples of waveform implementation triggers include triggers corresponding to fluctuations in target communication quality of a first signal waveform (or a signal waveform in which Transform precoding is disabled) and triggers corresponding to fluctuations in target communication quality of a second signal waveform (or a signal waveform in which Transform precoding is enabled).

[0369] For example, the terminal device 50 executes conditional handover when the target communication quality of the first signal waveform becomes worse than a first threshold and / or when the target communication quality of the second signal waveform becomes better than a second threshold.

[0370] For example, a waveform execution trigger may be a trigger according to the difference between the serving communication quality and the target communication quality.

[0371] For example, a waveform implementation trigger may be when the Serving communication quality of the first signal waveform (or the signal waveform for which Transform precoding is Disabled) becomes equal to or less than the Offset from the Target communication quality of at least one of the first signal waveform and the second signal waveform (or the signal waveform for which Transform precoding is Enable).

[0372] Alternatively, the waveform execution trigger may be when the serving communication quality of the second signal waveform becomes equal to or less than the offset from the target communication quality of at least one of the first signal waveform and the second signal waveform.

[0373] Alternatively, the waveform execution trigger may be when the Serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or less than the Offset from the Target communication quality of the first signal waveform.

[0374] Alternatively, the waveform execution trigger may be when the Serving communication quality of at least one of the first signal waveform and the second signal waveform becomes equal to or less than the Offset from the Target communication quality of the second signal waveform.

[0375] The first signal waveform of the waveform execution trigger may be appropriately interpreted as a signal waveform in which Transform precoding is disabled, and the second signal waveform of the waveform execution trigger may be appropriately interpreted as a signal waveform in which Transform precoding is enabled.

[0376] The information related to the execution trigger may include at least one of the following information: RSRP information of the target cell candidate RSRQ information of the target cell candidate RSSI information of the target cell candidate Timer information related to the execution of handover of the target cell candidate Information related to the start time of the execution of handover of the target cell candidate Information related to the start time of the detection operation of the handover execution trigger (e.g., waveform execution trigger) of the target cell candidate Information related to the operation after the timer related to the execution of handover of the target cell candidate expires Information related to the operation when a synchronization signal of a cell other than the target cell candidate is received

[0377] The detachment information regarding the execution of detachment from the serving base station may include at least one of the following information: RSRP information of the serving cell RSRQ information of the serving cell RSSI information of the serving cell Information on the timer for executing detachment from the serving cell Information on the time for executing detachment from the serving cell Information on the execution of detachment from the serving cell

[0378] The measurement information and the information regarding the measurement report may be the same as the measurement information and the information regarding the measurement report included in the above-mentioned instruction information. In this case, the target cell in the instruction information may be appropriately replaced with a target cell candidate (or a neighboring cell). Furthermore, the target base station in the instruction information may be appropriately replaced with a target base station candidate.

[0379] Note that one or more pieces of information included in the procedure information regarding the conditional handover procedure may be transmitted to the terminal device 50 as one piece of information (or notification), or may be notified individually.

[0380] <<4. Example of Communication Processing>> Here, a handover processing and a conditional handover processing will be described as an example of communication processing executed in the communication system SYS1.

[0381] 17 is a sequence diagram showing an example of the flow of handover processing according to an embodiment of the present disclosure. Note that in the handover processing in Fig. 17, the same processes as those in Fig. 5 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0382] 17 , the serving base station acquires waveform information from the target base station (step S301). This waveform information corresponds to the first waveform information described above. The waveform information includes at least one of information about the first signal waveform and information about the second signal waveform.

[0383] Based on the acquired waveform information, the serving base station notifies the terminal device 50 of measurement information (step S302). This measurement information includes waveform information relating to the signal waveform of at least one of the target cell and the serving cell.

[0384] The terminal device 50 performs measurements (measurement control) based on the measurement information and transmits a measurement report to the serving base station (step S303). Similarly, the terminal device 50 performs measurements based on the measurement information and transmits a measurement report to the target base station (step S304).

[0385] Here, the terminal device 50 reports a measurement report to the target base station, but the terminal device 50 may transmit, for example, a measurement report regarding the communication quality of the downlink signal of the target base station to the serving base station.

[0386] Subsequently, after step S106, the serving base station that has decided to perform handover transmits an RRC Reconfiguration including a handover command (step S305) to notify the execution of handover. This handover command includes, for example, waveform information of the target cell.

[0387] The terminal device 50 performs handover in accordance with the handover command.

[0388] 18 is a sequence diagram showing an example of the flow of a conditional handover process according to an embodiment of the present disclosure. Note that in the conditional handover process in Fig. 18, the same processes as those in Fig. 6 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0389] 18 , the serving base station acquires waveform information from the first target base station and the second target base station (step S401). This waveform information corresponds to the first waveform information described above. The waveform information includes at least one of information about the first signal waveform and information about the second signal waveform.

[0390] Based on the acquired waveform information, the serving base station notifies the terminal device 50 of measurement information (step S402). This measurement information includes waveform information on at least one signal waveform of the target candidate cells #1 and #2 and the serving cell.

[0391] The terminal device 50 performs measurements (measurement control) based on the measurement information, and transmits a measurement report to the serving base station (step S403).

[0392] Next, following step S208, the serving base station that has decided to perform conditional handover transmits an RRC Reconfiguration to the terminal device 50 (step S404). This RRC Reconfiguration includes, for example, information related to conditional handover.

[0393] The terminal device 50 performs a conditional handover in accordance with the information related to the conditional handover.

[0394] In this way, the serving base station obtains waveform information from the target base station (or the first or second target base station) and notifies the terminal device 50, so that the terminal device 50 can measure the communication quality of the downlink signal even when multiple signal waveforms are used.

[0395] The serving base station can perform processing (for example, handover determination) according to the communication quality of the downlink signal acquired from the terminal device 50.

[0396] This allows the communication system SYS1 to measure the quality of downlink signals in communications using multiple signal waveforms, and enables more efficient communications using multiple signal waveforms.

[0397] <<5. Relationship Between Signal Waveforms>> For example, the downlink signal waveform and the uplink signal waveform may have the following relationship.

[0398] For example, when the second signal waveform is set in the downlink communication, the second signal waveform is also set in the uplink communication.

[0399] In this case, the terminal device 50 assumes that the second signal waveform set in the downlink communication is also set in the uplink communication. In other words, when the second signal waveform is set in the downlink communication, the terminal device 50 assumes that the first signal waveform is not set in the uplink communication.

[0400] For example, when considering coverage such as a cell edge, it is assumed that the first signal waveform will be set for both the uplink and downlink.

[0401] For example, when a first signal waveform is set in downlink communication, the first signal waveform is also set in uplink communication.

[0402] In this case, the terminal device 50 assumes that the first signal waveform set in the downlink communication is also set in the uplink communication. That is, when the first signal waveform is set in the downlink communication, the terminal device 50 assumes that the second signal waveform is not set in the uplink communication.

[0403] In this way, for example, in a coverage area where communication using the first signal waveform is possible in downlink communication, it is expected that communication using the first signal waveform will also be performed in uplink communication.

[0404] Alternatively, when the first signal waveform is set in the downlink communication, the first signal waveform and / or the second signal waveform is set in the uplink communication.

[0405] In this case, the terminal device 50 assumes that when the first signal waveform is set in the downlink communication, the first signal waveform and / or the second signal waveform is set in the uplink communication.

[0406] For example, when the second signal waveform is set in the uplink communication, the second signal waveform is also set in the downlink communication.

[0407] In this case, the terminal device 50 assumes that the second signal waveform set in the uplink communication is also set in the downlink communication. That is, when the second signal waveform is set in the uplink communication, the terminal device 50 assumes that the first signal waveform is not set in the downlink communication.

[0408] For example, when considering coverage such as a cell edge, it is assumed that the first signal waveform will be set for both the uplink and downlink.

[0409] For example, when a first signal waveform is set in uplink communication, the first signal waveform is also set in downlink communication.

[0410] In this case, the terminal device 50 assumes that the first signal waveform set in the uplink communication is also set in the downlink communication. That is, when the first signal waveform is set in the uplink communication, the terminal device 50 assumes that the second signal waveform is not set in the downlink communication.

[0411] In this way, for example, in a coverage area where communication using the first signal waveform is possible in uplink communication, it is expected that communication using the first signal waveform will also be performed in downlink communication.

[0412] Alternatively, when the first signal waveform is set in the uplink communication, the first signal waveform and / or the second signal waveform is set in the downlink communication.

[0413] In this case, the terminal device 50 assumes that when the first signal waveform is set in the uplink communication, the first signal waveform and / or the second signal waveform is set in the downlink communication.

[0414] <<6. Signal Waveform Examples>> In the above-described embodiment, the first signal waveform is CP-OFDM and the second signal waveform is DFT-S-OFDM, but the signal waveforms are not limited to these examples.

[0415] For example, the first signal waveform may be a signal waveform of a multi-carrier system. For example, the multi-carrier system may be the following systems: - CP-OFDM with WOLA (Cyclic Prefix - Orthogonal Frequency Division Multiplexing with Weighted Overlap and Add) - UFMC (Universal Filter Multi Carrier) - FBMC (Filter-Bank Multi Carrier) - GFDM (Generalized Frequency Division Multiplexing)

[0416] For example, the second signal waveform may be a signal waveform of a single carrier system. For example, the single carrier system may be the following systems: - Constant envelope - SC-QAM (Single Carrier - Quadrature Amplitude Modulation) - SC-FDE (Single-carrier modulation with frequency domain equalization) - SC-FDM (Single Carrier - Frequency Division Multiplex) - Zero-tail SC-FDM

[0417] <<7. Hardware Configuration Example>> Next, a description will be given of a hardware configuration example of the base station 20 and the terminal device 50 according to each embodiment. The information devices of the base station 20 and the terminal device 50 described above are realized by, for example, a computer 1000 having a configuration as shown in FIG.

[0418] 19 is a block diagram showing an example hardware configuration of a computer 1000 according to the present disclosure. The computer 1000 includes a CPU 1100, a RAM 1200, a ROM 1300, a hard disk drive (HDD) 1400, a communication interface 1500, and an input / output interface 1600. The components of the computer 1000 are connected to each other via a bus 1050.

[0419] The CPU 1100 operates and controls each component based on programs stored in the ROM 1300 or the HDD 1400. For example, the CPU 1100 loads the programs stored in the ROM 1300 or the HDD 1400 into the RAM 1200 and executes processing corresponding to the various programs.

[0420] The ROM 1300 stores boot programs such as a Basic Input Output System (BIOS) that is executed by the CPU 1100 when the computer 1000 is started, and programs that depend on the hardware of the computer 1000 .

[0421] HDD 1400 is a computer-readable recording medium that non-temporarily records programs executed by CPU 1100 and data used by such programs. Specifically, HDD 1400 is a recording medium that records the proposed program according to the present disclosure, which is an example of program data 1450.

[0422] The communication interface 1500 is an interface for connecting the computer 1000 to an external network 1550 (e.g., the Internet). For example, the CPU 1100 receives data from other devices and transmits data generated by the CPU 1100 to other devices via the communication interface 1500.

[0423] The input / output interface 1600 is an interface for connecting the input / output device 1650 and the computer 1000. For example, the CPU 1100 receives data from an input device such as a keyboard or a mouse via the input / output interface 1600. The CPU 1100 also transmits data to an output device such as a display, a speaker, or a printer via the input / output interface 1600. The input / output interface 1600 may also function as a media interface for reading programs recorded on a predetermined recording medium. Examples of media include optical recording media such as a DVD (registered trademark) (Digital Versatile Disc) or a PD (Phase Change Rewritable Disk), magneto-optical recording media such as an MO (Magneto-Optical disk), tape media, magnetic recording media, or semiconductor memory.

[0424] The CPU 1100 executes programs loaded onto the RAM 1200 to realize the functions of the control units 103, 203, etc. The proposed program according to the present disclosure and data in the storage units 120, 320, and 420 are stored in the HDD 1400. The CPU 1100 reads and executes program data 1450 from the HDD 1400, but as another example, the CPU 1100 may obtain these programs from other devices via an external network 1550.

[0425] <<8. Other Embodiments>> The processing according to each of the above-described embodiments may be implemented in various different forms other than the above-described embodiments.

[0426] In the above-described embodiment, the communication system SYS1 uses the measurement results in the handover process, but the process using the measurement results is not limited to handover. For example, in dual connectivity, the measurement results for each signal waveform may be used.

[0427] In a dual connectivity environment, the terminal device 50 communicates by connecting to a plurality of base stations 20. In this case, the downlink signal waveform may be set for each of the plurality of base stations 20 to which the terminal device 50 is connected.

[0428] For example, assume that the terminal device 50 is connected to the base station 20A and the base station 20B via dual connectivity. In this case, the terminal device 50 may use a second signal waveform for downlink communication with the base station 20A and a first signal waveform for downlink communication with the base station 20B.

[0429] Alternatively, the terminal device 50 may use the first signal waveform in both downlink communication with the base station 20A and downlink communication with the base station 20B. The terminal device 50 may use the second signal waveform in both downlink communication with the base station 20A and downlink communication with the base station 20B.

[0430] In a dual connectivity environment, the terminal device 50 may acquire information (e.g., equivalent to the above-mentioned second waveform information) regarding the signal waveform used for downlink communication of one base station 20 (e.g., base station 20A) from the other base station 20 (e.g., base station 20B).

[0431] For example, the terminal device 50 receives a downlink signal from the other base station 20 based on the acquired second waveform information.

[0432] Also, for example, when a terminal device 50 is communicating with one base station 20 using both a first signal waveform and a second signal waveform, the communication using one of the signal waveforms may be switched from one base station 20 to another base station 20.

[0433] For example, assume that the terminal device 50 is communicating with the base station 20A using both the first signal waveform and the second signal waveform. In this case, the terminal device 50 may switch the downlink communication using the first signal waveform from the base station 20A to the base station 20B depending on the quality of the downlink communication using the first signal waveform with the base station 20A and / or the base station 20B.

[0434] For example, when the quality of downlink communication with base station 20A using a first signal waveform falls below a threshold, base station 20A (or terminal device 50) decides to switch downlink communication using the first signal waveform from base station 20A to base station 20B.

[0435] Alternatively, for example, when the quality of downlink communication using the first signal waveform with base station 20B becomes equal to or higher than a threshold, base station 20A (or terminal device 50) determines to switch downlink communication using the first signal waveform from base station 20A to base station 20B.

[0436] For example, when the quality of downlink communication with base station 20A using a first signal waveform falls below the quality of downlink communication with base station 20B using a first signal by more than the Offset, base station 20A (or terminal device 50) determines to switch from base station 20A to base station 20B.

[0437] In this way, in the communication system SYS1, the results of measurements according to waveform information can be used for various processes.

[0438] For example, the control device that controls the base station 20 and the terminal device 50 in each of the above-described embodiments may be realized by a dedicated computer system or a general-purpose computer system.

[0439] For example, a communication program for executing the above-described operations is stored on a computer-readable recording medium such as an optical disk, a semiconductor memory, a magnetic tape, or a flexible disk and distributed. Then, for example, the program is installed on a computer and the above-described processing is executed to configure a control device. In this case, the control device may be a device external to the base station 20 and the terminal device 50 (for example, a personal computer). Alternatively, the control device may be a device internal to the base station 20 and the terminal device 50 (for example, the control units 103 and 203).

[0440] The communication program may also be stored in a disk device provided in a server device on a network such as the Internet, and may be downloaded to a computer. The above-described functions may also be realized by a combination of an operating system (OS) and application software. In this case, the components other than the OS may be stored on a medium and distributed, or may be stored in a server device and downloaded to a computer.

[0441] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using a known method. In addition, the information including the processing procedures, specific names, various data, and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified. For example, the various information shown in each drawing is not limited to the information shown in the drawings.

[0442] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0443] Furthermore, the above-described embodiments can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0444] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0445] Furthermore, for example, each embodiment can be implemented as any configuration that constitutes an apparatus or system, such as a processor as a system LSI (Large Scale Integration), a module using multiple processors, a unit using multiple modules, a set in which other functions are added to a unit, or the like (i.e., a configuration of a part of an apparatus).

[0446] In each embodiment, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all of the components are in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0447] Furthermore, for example, each embodiment may have a cloud computing configuration in which one function is shared and processed jointly by a plurality of devices via a network.

[0448] <<9. Conclusion>> Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, components of different embodiments and modifications may be combined as appropriate.

[0449] Furthermore, the effects of each embodiment described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0450] Note that the present technology may also be configured as follows. (1) A base station comprising: a control unit that transmits, to a terminal device, first information for measuring communication quality of downlink communication, the first information including second information related to at least one of a first signal waveform and a second signal waveform; and receives a measurement result of the communication quality performed by the terminal device using at least one of the first signal waveform and the second signal waveform based on the first information, wherein the signal of the first signal waveform is a multicarrier signal and the signal of the second signal waveform is a single-carrier signal. (2) The base station according to (1), wherein the measurement result includes a result of measuring the communication quality of the downlink communication with another base station different from the base station that transmitted the first information. (3) The base station according to (2), wherein the control unit acquires the second information from the other base station. (4) The base station according to any one of (1) to (3), wherein the second information includes at least one of information on validity or invalidity of at least one of the first signal waveform and the second signal waveform, information on capability of at least one of the first signal waveform and the second signal waveform, and information on resources of at least one of the first signal waveform and the second signal waveform. (5) The base station according to any one of (1) to (4), wherein the control unit transmits handover information related to handover of the terminal device to the terminal device. (6) The base station according to (5), wherein the control unit determines whether the terminal device will perform handover based on the measurement result, and transmits the handover information to the terminal device when it is determined that the handover will be performed. (7) The base station according to (5), wherein the control unit transmits the handover information indicating whether the terminal device will perform a conditional handover to the terminal device. (8) The base station according to any one of (5) to (7), wherein the control unit transmits to the terminal device third information regarding at least one of the first signal waveform and the second signal waveform used in the downlink communication with the handover destination base station.(9) The base station according to (8), wherein the third information includes at least one of information on validity or invalidity of at least one of the first signal waveform and the second signal waveform, information on capability of at least one of the first signal waveform and the second signal waveform, and information on resource of at least one of the first signal waveform and the second signal waveform. (10) The base station according to (8) or (9), wherein the control unit includes the third information in the handover information and transmits it to the terminal device. (11) The base station according to any one of (5) to (10), wherein the control unit transmits at least one of fourth information on measurement of communication quality of the downlink communication with the handover destination base station and fifth information on notification of a measurement result of the communication quality of the downlink communication with the handover destination base station to the terminal device. (12) The base station according to (11), wherein the control unit includes at least one of the fourth information and the fifth information in the handover information and transmits it to the terminal device. (13) The base station according to any one of (1) to (12), wherein the control unit transmits a first signal having the first signal waveform and used for the measurement of the downlink communication, and a second signal having the second signal waveform and used for the measurement of the downlink communication. (14) The base station according to (13), wherein the first signal and the second signal are synchronization signal blocks. (15) The base station according to (13), wherein the first signal and the second signal are reference signals for the downlink communication. (16) The base station according to (15), wherein a common synchronization signal and a broadcast channel are used for the first signal waveform and the second signal waveform. (17) The base station according to any one of (1) to (16), wherein the control unit receives from the terminal device a report including both the measurement result of the communication quality of the downlink communication in the first signal waveform and the measurement result of the communication quality of the downlink communication in the second signal waveform. (18) The base station according to any one of (1) to (17), wherein the control unit performs the downlink communication with the terminal device according to the measurement result.(19) A terminal device comprising: a control unit that receives, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measures the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notifies the base station of the measurement result of the communication quality of the downlink communication; wherein the signal of the first signal waveform is a multi-carrier signal, and the signal of the second signal waveform is a single-carrier signal. (20) A communication method comprising: transmitting, to a terminal device, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; and receiving, based on the first information, a measurement result of the communication quality performed by the terminal device using at least one of the first signal waveform and the second signal waveform, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal. (21) A communication method comprising: receiving, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measuring the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notifying the base station of a measurement result of the communication quality of the downlink communication, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.(22) A communication program causing a computer to execute the following: transmitting, to a terminal device, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; and receiving, based on the first information, a measurement result of the communication quality performed by the terminal device using at least one of the first signal waveform and the second signal waveform, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal. (23) A communication program causing a computer to execute the following steps: receive, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measure the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notify the base station of the measurement result of the communication quality of the downlink communication, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

[0451] 20 Base station 50 Terminal device 101, 201 Upper layer processing unit 103, 203 Control unit 105, 205 Receiving unit 107, 207 Transmitting unit 109, 209 Transmitting / receiving antenna 120 Storage unit

Claims

1. A base station comprising: a control unit that transmits to a terminal device first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; and receives a result of the communication quality measurement performed by the terminal device using at least one of the first signal waveform and the second signal waveform based on the first information; wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

2. The base station according to claim 1, wherein the measurement results include results of measuring the communication quality of the downlink communication with another base station different from the base station that transmitted the first information.

3. The base station according to claim 2, wherein the control unit acquires the second information from the other base station.

4. The base station according to claim 1, wherein the second information includes at least one of information regarding the validity or invalidity of at least one of the first signal waveform and the second signal waveform, information regarding the capability of at least one of the first signal waveform and the second signal waveform, and information regarding the resources of at least one of the first signal waveform and the second signal waveform.

5. The base station according to claim 1, wherein the control unit transmits handover information regarding handover of the terminal device to the terminal device.

6. The base station according to claim 5, wherein the control unit determines whether or not the terminal device will perform a handover based on the measurement results, and transmits the handover information to the terminal device if it determines that the handover will be performed.

7. The base station according to claim 5, wherein the control unit transmits the handover information indicating whether or not the terminal device will perform a conditional handover to the terminal device.

8. The base station according to claim 5, wherein the control unit transmits to the terminal device third information relating to at least one of the first signal waveform and the second signal waveform used in the downlink communication with the handover destination base station.

9. The base station according to claim 5, wherein the control unit transmits to the terminal device at least one of fourth information regarding measurement of the communication quality of the downlink communication with the handover destination base station and fifth information regarding notification of the measurement result of the communication quality of the downlink communication with the handover destination base station.

10. The base station according to claim 1, wherein the control unit transmits a first signal having the first signal waveform, the first signal being used for the measurement of the downlink communication, and a second signal having the second signal waveform, the second signal being used for the measurement of the downlink communication.

11. The base station according to claim 10, wherein the first signal and the second signal are synchronization signal blocks.

12. The base station of claim 10, wherein the first signal and the second signal are reference signals for the downlink communication.

13. The base station according to claim 12, wherein the first signal waveform and the second signal waveform use a common synchronization signal and broadcast channel.

14. The base station according to claim 1, wherein the control unit receives from the terminal device a report including both the measurement result of the communication quality of the downlink communication in the first signal waveform and the measurement result of the communication quality of the downlink communication in the second signal waveform.

15. The base station according to claim 1, wherein the control unit performs the downlink communication with the terminal device according to the measurement result.

16. A terminal device comprising: a control unit that receives, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measures the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notifies the base station of the measurement result of the communication quality of the downlink communication; wherein the signal of the first signal waveform is a multi-carrier signal, and the signal of the second signal waveform is a single-carrier signal.

17. A communication method comprising: transmitting to a terminal device first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; and receiving a result of the communication quality measurement performed by the terminal device using at least one of the first signal waveform and the second signal waveform based on the first information, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

18. A communication method comprising: receiving, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measuring the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notifying the base station of the measurement result of the communication quality of the downlink communication, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

19. A communications program that causes a computer to execute the following steps: transmit to a terminal device first information for measuring communication quality of downlink communications, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; and receive, based on the first information, a measurement result of the communication quality performed by the terminal device using at least one of the first signal waveform and the second signal waveform, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

20. A communications program that causes a computer to execute the following steps: receive, from a base station, first information for measuring communication quality of downlink communication, the first information including second information relating to at least one of a first signal waveform and a second signal waveform; measure the communication quality of the downlink communication using at least one of the first signal waveform and the second signal waveform based on the first information; and notify the base station of the measurement result of the communication quality of the downlink communication, wherein the signal of the first signal waveform is a multi-carrier signal and the signal of the second signal waveform is a single-carrier signal.

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