Base station, terminal device, and communication method

Abstract

A base station system of the present disclosure applies a first resource mapping to a plurality of signals to map the plurality of signals to a first physical resource or a logical resource and generate a first mapped signal. The base station system performs a Fourier transform on the first mapped signal to generate a first transformed signal. The base station system applies a second resource mapping to the first transformed signal to map the first transformed signal to a second physical resource and generate a second mapped signal. The base station system performs an inverse Fourier transform on the second mapped signal to generate a second transformed signal. The base station system generates a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal.

Description

BASE STATION, TERMINAL DEVICE, AND COMMUNICATION METHOD

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

[0002] A wireless access scheme and a wireless network for cellular mobile communication (hereinafter 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 under consideration by the 3rd Generation Partnership Project (3GPP (registered trademark)).

[0003] Moreover, in the following description, LTE is construed to encompass LTE-A, LTE-A Pro, and EUTRA, and NR is construed to encompass NRAT and FEUTRA. In LTE, a base station (base station equipment) is referred to as evolved NodeB (eNodeB), whereas in NR, a base station (base station equipment) is referred to as gNodeB, and in LTE and NR, a terminal device (mobile station, mobile station equipment, or terminal) is referred to as user equipment (UE). LTE and NR are cellular communication systems in which a plurality of cells is arranged in a cellular structure, each covered by a base station. A single base station can manage a plurality of cells.

[0004] 5G NR is a radio access technology (RAT), serving as a next-generation radio access scheme for LTE. NR is an access technology capable of supporting various use cases including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra reliable and low latency communications (URLLC). Standardization of NR has progressed to support a technical framework corresponding to usage scenarios, requirements, deployment scenarios, and the like in those use cases.

[0005] In recent years, support for high-frequency bands such as millimeter wave and terahertz wave has progressed, along with efforts to reduce the cost of a base station. Accordingly, there is an increasing demand for reducing the peak-to-average-power ratio (PAPR) in downlink communication.

[0006] Japanese Translation of PCT International Application Laid-open No. 2022-551796

[0007] R1-1706156, "NR PSS and SSS Design", Intel Corporation, RAN1 #88bis, 7th April 2017

[0008] In order to address the problem of PAPR caused by factors such as cost reduction of a base station as described above, there is a need to consider techniques for implementing communication more effectively.

[0009] Thus, 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.

[0010] Note that the above-described problem or objective is merely one of plurality of problems or objectives that can be solved or achieved by a plurality of embodiments disclosed herein.

[0011] A base station system of the present disclosure applies a first resource mapping to a plurality of signals to map the plurality of signals to a first physical resource or a logical resource and generate a first mapped signal. The base station system performs a Fourier transform on the first mapped signal to generate a first transformed signal. The base station system applies a second resource mapping to the first transformed signal to map the first transformed signal to a second physical resource and generate a second mapped signal. The base station system performs an inverse Fourier transform on the second mapped signal to generate a second transformed signal. The base station system generates a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal.

[0012] Fig. 1 is a diagram illustrating an example of signal processing for uplink communication in 5G NR.Fig. 2 is a diagram illustrating an example of a wireless network provided by a communication system.Fig. 3 is a diagram illustrating an overview of satellite communication provided by a communication system.Fig. 4 is a diagram illustrating an example of a cell covered by a non-geostationary satellite.Fig. 5 is a diagram illustrating an example of resource allocation for a PDCCH.Fig. 6 is a diagram illustrating an example of resource allocation for a PBCH.Fig. 7 is a diagram illustrating an example of resource allocation for a DMRS included in a PDCCH.Fig. 8 is a diagram illustrating an example of resource allocation for a DMRS included in a PBCH.Fig. 9 is a diagram illustrating an example of communication processing according to the technology of the present disclosure.Fig. 10 is a diagram illustrated to describe an overall configuration example of a communication system according to an embodiment of the present disclosure.Fig. 11 is a block diagram illustrating an exemplary configuration of a base station according to an embodiment of the present disclosure.Fig. 12 is a block diagram illustrating an exemplary configuration of a wireless transmission unit according to an embodiment of the present disclosure.Fig. 13 is a block diagram illustrating an exemplary configuration of a first signal waveform transmission unit according to an embodiment of the present disclosure.Fig. 14 is a block diagram illustrating an exemplary configuration of a second signal waveform transmission unit according to an embodiment of the present disclosure.Fig. 15 is a block diagram illustrating an exemplary configuration of a terminal device according to an embodiment of the present disclosure.Fig. 16 is a block diagram illustrating an exemplary configuration of a wireless reception unit according to an embodiment of the present disclosure.Fig. 17 is a block diagram illustrating an exemplary configuration of a first signal waveform reception unit according to an embodiment of the present disclosure.Fig. 18 is a block diagram illustrating an exemplary configuration of a second signal waveform reception unit according to an embodiment of the present disclosure.Fig. 19 is a sequence diagram illustrating a communication processing procedure for downlink communication according to an embodiment of the present disclosure.Fig. 20 is a diagram illustrating an example of signal processing for downlink communication according to an embodiment of the present disclosure.Fig. 21 is a diagram illustrating an example of multiplexing synchronization signals according to an embodiment of the present disclosure.Fig. 22 is a diagram illustrating an example of multiplexing synchronization signals and system information according to an embodiment of the present disclosure.Fig. 23 is a diagram illustrating an example of multiplexing system information and a reference signal according to an embodiment of the present disclosure.Fig. 24 is a diagram illustrating an example of multiplexing synchronization signals, system information, and a reference signal according to an embodiment of the present disclosure.Fig. 25 is a diagram illustrating another example of multiplexing synchronization signals and system information according to an embodiment of the present disclosure.Fig. 26 is a diagram illustrating another example of multiplexing synchronization signals and system information according to an embodiment of the present disclosure.Fig. 27 is a diagram illustrating an example of multiplexing a control signal and a reference signal according to an embodiment of the present disclosure.Fig. 28 is a diagram illustrating an example of CCE-to-REG mapping with interleaving applied.Fig. 29 is a diagram illustrating an example of CCE-to-REG mapping without interleaving applied.Fig. 30 is a diagram illustrating an example of multiplexing a data signal and a reference signal according to an embodiment of the present disclosure.Fig. 31 is a diagram illustrating another example of multiplexing a data signal and a reference signal according to an embodiment of the present disclosure.Fig. 32 is a diagram illustrating an example of multiplexing reference signals according to an embodiment of the present disclosure.Fig. 33 is a diagram illustrating an example of a resource set according to an embodiment of the present disclosure.Fig. 34 is a diagram illustrating an example of downlink signal reception processing according to an embodiment of the present disclosure.Fig. 35 is a diagram illustrating an example of downlink signal reception processing according to an embodiment of the present disclosure.Fig. 36 is a diagram illustrating another example of downlink signal reception processing according to an embodiment of the present disclosure.Fig. 37 is a diagram illustrating another example of downlink signal reception processing according to an embodiment of the present disclosure.Fig. 38 is a diagram illustrating another example of downlink signal reception processing according to an embodiment of the present disclosure.

[0013] Detailed descriptions of embodiments of the present disclosure are provided below with reference to the accompanying drawings. Note that, in the following description and drawings herein, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0014] In addition, in the description and drawings herein, similar components among the embodiments can be distinguished by appending at least one of different letters and numbers to the same reference numeral. However, in a case where there is no need to particularly distinguish each of the similar components, only the same reference numeral can be used.

[0015] One or more embodiments (including examples, modifications, and application examples) described below can be implemented independently. On the other hand, at least a portion of the plurality of embodiments described below can be implemented in appropriate combination with at least a portion of other embodiments. The plurality of embodiments can include mutually different novel features. Thus, the plurality of embodiments can contribute to solving different purposes or problems and can provide different advantages or effects.

[0016] <<1. Introduction>> <1-1. Background> <1-1-1. DFT-S-OFDM Transmission> In uplink communications in 5G NR, orthogonal frequency division multiplexing (OFDM) transmission and discrete Fourier transform spread OFDM (DFT-S-OFDM) transmission are used.

[0017] Fig. 1 is a diagram illustrating an example of signal processing for uplink communication in 5G NR.

[0018] As illustrated in Fig. 1, error correction parity bits are added to the transmission signal sequence through error correction code (channel coding). Subsequently, rate matching extracts a number of bits corresponding to a transmission resource and a modulation scheme from the transmission signal sequence. Interleaving and scrambling are applied to the extracted bits.

[0019] Then, the bit sequence is mapped to a complex constellation point through modulation processing. In the case of performing transmission using a plurality of layers, the bit sequence is mapped to complex constellation points in each layer.

[0020] At this point, in DFT-S-OFDM transmission, as illustrated in Fig. 1, discrete Fourier transformation (DFT) processing called transform precoding is performed. Moreover, the processing at this stage, i.e., the DFT processing performed at this stage, can be referred to by a name other than transform precoding. Additionally, in OFDM transmission, the transform precoding processing is omitted.

[0021] Then, precoding is applied to assign a transmission weight, and after a resource mapping is performed, through OFDM processing, the transmission signal in the frequency domain is transformed into a transmission signal in the time domain (i.e., a time-axis signal) and transmitted. The processing in Fig. 1 pertains to uplink communication, so the time-domain transmission signal is transmitted from a terminal device to a base station.

[0022] On the receiving side, the received signal in the time domain is first transformed into a signal in the frequency-domain signal (frequency-axis signal) through OFDM processing. Then, after a resource de-mapping is performed, frequency equalization processing (using an equalizer) is performed to compensate for distortion due to radio wave propagation.

[0023] At this stage, in DFT-S-OFDM transmission, as illustrated in Fig. 1, inverse discrete Fourier transformation (IDFT) processing called transform de-precoding is performed. In OFDM transmission, this transform de-precoding processing is omitted.

[0024] Thereafter, signals mapped to a plurality of layers are demapped, and a soft decision is made on each bit from the complex constellation point. The bit values obtained through the soft-decision processing are subjected to de-scrambling, de-interleaving, de-rate matching, and channel decoding to obtain a reception signal sequence.

[0025] As described above, in conventional uplink communication, a single-carrier transmission scheme (e.g., DFT-S-OFDM transmission in the example described above) has been introduced for the purpose of reducing PAPR.

[0026] In this regard, as described above, in recent years, support for high-frequency bands such as millimeter waves and terahertz waves, along with efforts to reduce the cost in a base station have led to a demand for reduced PAPR in downlink communications as well.

[0027] In view of such considerations as such cost reduction and coverage expansion of a base station, it is conceivable to introduce a single-carrier scheme with low PAPR into downlink communications as well.

[0028] <1-1-2. Satellite Communication> One example of a type of communication in which PAPR reduction is desired is satellite communication. One type of mobile satellite used in satellite communication is a small satellite, also referred to as, for example, a Cube-sat or micro-satellite. Small satellites are inferior to conventional satellites in terms of power and antenna gain. Thus, one of the issues with small satellites is the problem of PAPR, which arises from the inability to mount a high-performance power amplifier.

[0029] For this reason, the introduction of a single-carrier scheme with low PAPR is being considered for satellite communication as well.

[0030] An overview of satellite communication is now described. For example, in cellular mobile communication, a base station (e.g. eNodeB (eNB), gNodeB (gNB), RAN node (including EUTRAN and NG-RAN)) or a relay device installed on the ground configures a cell (e.g. a macrocell, microcell, femtocell, or small cell) and provides a wireless network. A base station or relay device installed on the ground is also referred to as a terrestrial station.

[0031] The wireless network provided by such a terrestrial station is referred to as a terrestrial network.

[0032] On the other hand, due to increasing demands for reducing the cost of a base station and providing coverage in regions where radio waves from a base station are difficult to reach, wireless networks are also being considered that are provided to a terminal device via a base station or relay station other than a terrestrial station, such as a satellite station or airborne station. Such a base station or relay station other than a terrestrial station is referred to as a non-terrestrial station (or non-terrestrial base station or non-terrestrial relay station).

[0033] Further, the wireless network provided by such a non-terrestrial station is referred to as a non-terrestrial network (NTN).

[0034] Examples of a communication device other than a terrestrial station include a satellite station and an airborne station. A satellite station refers to a device equipped with wireless communication functionality that operates outside of the Earth's atmosphere, such as an artificial satellite. The satellite station is herein construed to include low earth orbiting (LEO) satellite, medium earth orbiting (MEO) satellite, geostationary earth orbiting (GEO) satellite, and highly elliptical orbiting (HEO) satellite.

[0035] An airborne station refers to a device equipped with wireless communication functionality that operates within the Earth's atmosphere, such as an aircraft or a balloon. The airborne stations referred to herein is construed to include an unmanned aircraft system (UAS), tethered UAS, lighter-than-air UAS (LTA), heavier-than-air UAS (HTA), and high-altitude UAS Platforms (HAPs).

[0036] Moreover, a communication device other than a terrestrial station can also be referred to as base stations (e.g. eNodeB (eNB), gNodeB (gNB), RAN node (including EUTRAN and NG-RAN)) from the perspective of cellular mobile communication compliant with 3GPP (registered trademark).

[0037] Fig. 2 is a diagram illustrating an overview of a wireless network including a non-terrestrial network. Fig. 2 illustrates an example of a wireless network provided by a communication system SYS1. The communication system SYS1 in Fig. 2 includes a management device 101, terrestrial stations 201to 205, non-terrestrial stations 301to 305, relay stations 401and 402, and terminal devices 501and 502.

[0038] The communication system SYS1 provides users with a wireless network capable of mobile communication to users by each wireless communication device that constitutes the communication system SYS1 operating in cooperation. The wireless network of the present embodiment can be configured, for example, from a radio access network and a core network. Moreover, the wireless communication device refers herein to a device that has wireless communication functionality, and in the example of Fig. 2, this corresponds to a terrestrial station 20, a non-terrestrial station 30, a relay station 40, and a terminal device 50.

[0039] The management device 10 is, for example, a device that constitutes a core network CN1. The management device 10 is connected to a network PN1. The management device 10 is connected to the terrestrial stations 20 and the non-terrestrial stations 30, enabling the terminal devices 50 to connect to the network PN1. The network PN1 is a public data network such as the Internet. The network PN1 is not limited to the Internet and can be, for example, a local area network (LAN), a wide area network (WAN), a telephone network (such as a mobile or fixed telephone network), or a regional Internet protocol (IP) network. Naturally, the network PN1 can be another type of mobile network. For example, the network PN1 can be a cellular network provided by an entity (e.g., a business entity such as a mobile network operator (MNO)) that is different from the entity that operates the communication system SYS1.

[0040] The terrestrial stations 20 and the non-terrestrial stations 30 function as a base station or a relay station. In the following description, the terrestrial stations 20 and the non-terrestrial stations 30 are described as base stations, although the terrestrial stations 20 and the non-terrestrial stations 30 can alternatively function as relay stations. The terrestrial stations 20 are, for example, terrestrial base stations installed on a ground-based structure, while the non-terrestrial stations 30 are, for example, non-terrestrial base stations such as satellite stations or high-altitude platform stations (HAPS). Each of the terrestrial stations 20 and the non-terrestrial stations 30 constitutes a cell. A cell refers to an area covered by wireless communication. The cell can be any of a macrocell, a microcell, a femtocell, and a small cell. Moreover, the communication system SYS1 can be configured such that a single base station (e.g., a satellite station) manages a plurality of cells, or a plurality of base stations manages a single cell.

[0041] In the example of Fig. 2, the terrestrial stations 201and 202constitute a terrestrial network TN1, and terrestrial stations 203, 204, and 205constitute a terrestrial network TN2. The terrestrial networks TN1 and TN2 are networks operated by, for example, a wireless communication carrier such as a telephone company.

[0042] The terrestrial networks TN1 and TN2 can be operated by different wireless communication carriers or by the same wireless communication carrier. It is also possible to regard the terrestrial networks TN1 and TN2 as a single terrestrial network.

[0043] The terrestrial networks TN1 and TN2 are respectively connected to a core network. In the example of Fig. 2, the terrestrial stations 20 constituting the terrestrial network TN2 are connected to, for example, a core network CN1 constituted by the management device 101or the like.

[0044] If the radio access scheme of the terrestrial network TN2 is LTE, the core network CN1 is EPC. In addition, if the radio access scheme of the terrestrial network TN2 is NR, the core network CN1 is 5GC. It is understood that the core network CN1 is not limited to EPC or 5GC and can be a core network of another type of radio access scheme.

[0045] Moreover, although in the example of Fig. 2, the terrestrial network TN1 is not illustrated as being connected to a core network, but the terrestrial network TN1 can be connected to the core network CN1. Alternatively, the terrestrial network TN1 can be connected to a core network (not illustrated) different from the core network CN1.

[0046] 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.

[0047] The gateway device can be a server device connected to the Internet or a regional IP network. The gateway switch is, for example, a switching device connected to a telephone network of a telecommunications carrier. The management device 101can function as a gateway device or a gateway switch.

[0048] The non-terrestrial stations 30 illustrated in Fig. 2 are, for example, satellite stations or aircraft stations. A group of satellite stations (or a single satellite station) constituting a non-terrestrial network is referred to as a space-borne platform. In addition, a group of aircraft stations (or a single aircraft station) constituting a non-terrestrial network is referred to as an airborne platform.

[0049] In the example of Fig. 2, the non-terrestrial stations 301, 302, and 303constitute a space-borne platform SBP1, and the non-terrestrial station 304constitutes a space-borne platform SBP2. Additionally, the non-terrestrial station 305constitutes an airborne platform ABP1.

[0050] The non-terrestrial stations 30 can be capable of communicating with the terrestrial network or the core network via the relay stations 40. It is understood that the non-terrestrial stations 30 can be capable of communicating directly with the terrestrial network or the core network without passing through the relay stations 40.

[0051] Moreover, the non-terrestrial stations 30 can be capable of communicating with the terminal devices 50 via the relay stations 40 or can be capable of communicating directly with the terminal devices 50. The non-terrestrial stations 30 can also be capable of communicating directly with each other without passing through the relay stations 40.

[0052] The relay stations 40 relay communication between a terrestrial device and the non-terrestrial stations 30. The relay station is also referred to as an earth station (a very small aperture terminal, a gateway, a control earth station, a hub station). The relay stations 40 can be a terrestrial station or a non-terrestrial station. In the example of Fig. 2, the relay station 402relays communication between the terrestrial stations 20 and the non-terrestrial stations 30, and the relay station 401relays communication between the management device 10 and the non-terrestrial stations 30.

[0053] Moreover, the relay stations 40 can also relay communication between the terminal devices 50 and the non-terrestrial stations 30. Furthermore, the relay stations 40 can be capable of communicating with other relay stations 40.

[0054] The terminal devices 50 are capable of communicating with both terrestrial stations and non-terrestrial stations. In the example of Fig. 2, the terminal device 501is capable of communicating with a terrestrial station constituting the terrestrial network TN1. Furthermore, the terminal device 501is capable of communicating with a non-terrestrial station constituting the space-borne platforms SBP1 and SBP2.

[0055] Further, the terminal devices 50 are also capable of communicating with a non-terrestrial station constituting the airborne platform ABP1. Moreover, the terminal devices 50 can be capable of communicating with the relay station 40. In addition, the terminal devices 50 can be capable of direct communication with other terminal devices 50. The terminal device 501can be capable of direct communication with the terminal device 502.

[0056] Examples of the terminal devices 50 (i.e., earth terminal device) compatible with a non-terrestrial network include, for example, mobile phones and smartphones, automobiles and buses, trains, airplanes, machine-to-machine (M2M) or Internet of things (IoT) devices, relay stations that relay satellite communications, and base stations that receive satellite communication.

[0057] Each device constituting the space-borne platforms SBP1 and SBP2 performs satellite communication with the terminal devices 50. The term satellite communication refers to wireless communication between a satellite station and a communication device.

[0058] Fig. 3 is a diagram illustrating an overview of satellite communication provided by the communication system SYS1. Satellite stations are typically classified into geostationary satellite stations and low-earth orbit satellite stations.

[0059] A geostationary satellite station is a satellite station located in a geostationary orbit and revolves around the Earth at the same speed as the Earth's rotation speed. In the example of Fig. 3, the non-terrestrial station 304, which constitutes the space-borne platform SBP2, is a geostationary satellite station. A geostationary orbit is an orbital path among satellite orbits, which is located at an altitude of approximately 35,786 km.

[0060] The geostationary orbit is also referred to as a geostationary earth orbit (GEO). A geostationary satellite station has a relative speed of substantially zero (0) with respect to the terminal devices 50 on the ground, and thus appears stationary to the terminal devices 50 on the ground. The non-terrestrial station 304performs satellite communication with the terminal devices 501, 503, 504, and the like, located on the Earth.

[0061] A low-earth orbit satellite station is a satellite station that orbits in a low orbit. In the example of Fig. 3, the non-terrestrial stations 301and 302constituting the space-borne platform SBP1 are low-earth orbit satellite stations. A low-earth orbit is defined as an orbital path among satellite orbits, which is located at an altitude of approximately 2000 km or less. The low-earth orbit is also referred to as a low-earth orbit (LEO).

[0062] Unlike a geostationary satellite station, a low-earth orbit satellite station has a relative velocity with respect to the terminal devices 50 on the ground and appears to be moving when observed from the terminal devices 50 on the ground. Each of the non-terrestrial stations 301and 302form a cell, and perform satellite communication with terminal devices 501, 503, 504, or the like, located on the Earth.

[0063] Moreover, Fig. 3 illustrates only two satellite stations, i.e., the non-terrestrial stations 301and 302are illustrated as constituting the space-borne platform SBP1. However, in practice, a satellite constellation is formed by a large number of satellite stations. In such a case, the number of satellite stations constituting the space-borne platform SBP1 is three or more (e.g., from several tens to several thousands).

[0064] In the example of Fig. 3, only geostationary satellite stations and low-earth orbit satellite stations are illustrated as satellite stations, but the satellite stations constituting the communication system SYS1 can also include medium-earth orbit satellite stations. The medium-earth orbit satellite station is a satellite station that orbits in a medium orbit. The medium orbit is an orbit that is intermediate between a low orbit and a geostationary orbit. The medium orbit is also referred to as a medium earth orbit (MEO).

[0065] Further, the satellite stations constituting the communication system SYS1 can also include a highly elliptical orbit satellite station that is located in a highly elliptical orbit (HEO). Moreover, the satellite stations forming the satellite constellation can include not only low-earth orbit satellite stations, but also medium orbit satellite stations, highly elliptical orbit satellite stations, and geostationary satellite stations.

[0066] Fig. 4 is a diagram illustrating an example of a cell constituted by a non-geostationary satellite. Fig. 4 illustrates a cell C1 formed by the non-terrestrial station 302. In the example of Fig. 4, the non-terrestrial station 302is a low-earth orbit satellite station. A satellite station orbiting in a low-earth orbit communicates with the terminal devices 50 on the ground with a predetermined directivity on the ground.

[0067] For example, in the example illustrated in Fig. 4, the angle R is 40 degrees. In the example of Fig. 4, the radius D of the cell C1 formed by the non-terrestrial station 302is, for example, 1000 km. The low-earth orbit satellite station moves at a constant velocity. If it becomes difficult for the low-earth orbit satellite station to continue providing satellite communications to the terminal devices 50 on the ground, a subsequent low-earth orbit satellite station (neighbor satellite station) provides the satellite communications.

[0068] In the example of Fig. 4, if it becomes difficult for the non-terrestrial station 302to provide satellite communication to the terminal devices 50 on the ground, the subsequent non-terrestrial station 303provides the satellite communication. Moreover, the values of the angle R and the radius D described above are merely examples and are not limited to the above example.

[0069] The medium-earth orbit satellite and the low-earth orbit satellite travel on their orbits at a very high speed in the sky. For example, the low-earth orbit satellite at an altitude of 600 km travels on its orbit at a speed of 7.6 km / s.

[0070] The low-earth orbit satellite forms a cell (or beam) on the ground with a radius of several tens to several hundreds of km, but since the cells formed on the ground also move in accordance with the movement of the satellite, handover can be necessary even if the terminal device on the ground is stationary. For example, in 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 approximately every 6 to 7 seconds.

[0071] As described above, the terminal devices 50 are capable of wireless communication using a non-terrestrial network. In addition, the non-terrestrial stations 30 of the communication system SYS1 constitute a non-terrestrial network. This makes it possible for the communication system SYS1 to extend service coverage to the terminal devices 50 located in an area that is not covered by the terrestrial network.

[0072] For example, the communication system SYS1 is capable of providing services to the terminal devices 50 in areas that are out of coverage of the terrestrial network (e.g., out of coverage of a cell provided by a terrestrial station 20). The communication system SYS1 is capable of providing public safety communication and critical communication to communication devices such as Internet of things (IoT) devices and machine type communication (MTC) devices.

[0073] Further, the use of a non-terrestrial network improves service reliability and recoverability. This enables the communication system SYS1 to reduce the vulnerability of services to physical attacks or natural disasters.

[0074] Further, the communication system SYS1 is capable of implementing service connectivity to airborne terminal devices such as airplane passengers and drones, as well as service connections to mobile terminal devices such as ships and trains. In addition, the communication system SYS1 is capable of providing high-efficiency multicast services such as A / V content, group communication, IoT broadcast services, software download services, and emergency messaging, as well as highly efficient broadcast services. Furthermore, the communication system SYS1 is also capable of implementing traffic offloading between terrestrial network and non-terrestrial network.

[0075] Moreover, although satellite communication has been cited as an example of wireless communication that introduces a single-carrier scheme into downlink communication, wireless communication that introduces a single-carrier scheme is not limited to satellite communication. In other words, the technology according to the present embodiment is not limited to application to non-terrestrial networks and is also applicable to terrestrial networks.

[0076] In the following, for the sake of simplicity of description, the technology according to the present embodiment will be described using downlink communication in a terrestrial network as an example, but the technology according to the present embodiment can also be applied to downlink communication in a non-terrestrial network.

[0077] <1-2. Problems to be Solved> As mentioned above, in recent years, the reduction of PAPR (or cubic metric (CM)) in downlink communication has become increasingly important due to the support for high-frequency bands such as millimeter waves and terahertz waves, as well as the need to reduce the cost of base stations.

[0078] Further, a small satellite (which can be referred to as, for example, Cube-sat or micro-satellite) being considered as one type of mobile satellite is inferior to conventional satellites in terms of power and antenna gain. Thus, in small satellites, PAPR becomes a problem due to not having a high-performance power amplifier.

[0079] For the purpose of reducing PAPR, the introduction of a single-carrier scheme (e.g., DFT-S-OFDM) to downlink communications is being considered.

[0080] In introducing a single-carrier scheme to downlink communication, it is desirable to allocate the desired signal continuously in the frequency domain in order to suppress an increase in PAPR.

[0081] However, in 5G NR and the like, a control signal (e.g., physical downlink control channel (PDCCH) and physical broadcast channel (PBCH) and some of reference signals included in the control signals (e.g., demodulation reference signal (DMRS) included in PDCCH and PBCH)) can be transmitted using resources that are discontinuously allocated in the frequency domain. Thus, in the case of transmitting such signals, there is a risk that PAPR will increase.

[0082] Fig. 5 is a diagram illustrating an example of PDCCH resource allocation. As illustrated in Fig. 5, in 5G NR and the like, PDCCH is allocated for each UE in the frequency-time resource. Moreover, while Fig. 5 illustrates PDCCHs addressed to the first to third UEs, the number of UEs to which PDCCH is addressed can be two or fewer, or four or more.

[0083] Fig. 6 is a diagram illustrating an example of resource allocation of PBCH. As illustrated in Fig. 6, in 5G NR and the like, PBCH is allocated discontinuously in a frequency-time resource. In addition, primary synchronization signal (PSS) and secondary synchronization signal (SSS) are also allocated discontinuously in time.

[0084] As described above, a discontinuously allocated signal is not limited to a control signal and a reference signal. For example, a synchronization signal can also be allocated discontinuously.

[0085] Fig. 7 is a diagram illustrating an example of resource allocation of DMRS included in PDCCH. Fig. 7(a) illustrates an example of DMRS allocation in the case of 1-symbol CORESET. Fig. 7(b) illustrates an example of DMRS allocation in the case of 2-symbol CORESET. Fig. 7(c) illustrates an example of DMRS allocation in the case of 3-symbol CORESET. As illustrated in Fig. 7, DMRS is allocated discontinuously in frequency within PDCCH.

[0086] Fig. 8 illustrates an example of resource allocation of DMRS included in PBCH. Fig. 8(a) illustrates an example of DMRS allocation in the case of PCI = 0. Fig. 8(b) illustrates an example of DMRS allocation in the case of PCI = 1. Fig. 8(c) illustrates an example of DMRS allocation in the case of PCI = 2. Fig. 8(d) illustrates an example of DMRS allocation in the case of PCI = 3. As illustrated in Fig. 8, DMRS is allocated discontinuously in frequency with PBCH.

[0087] As such, in 5G NR and the like, some signals are allocated discontinuously in the frequency domain. In the case of transmitting such signals, there is a risk that PAPR will increase.

[0088] <1-3. Overview of Present Technology> Fig. 9 is a diagram illustrating an example of communication processing according to the present technology of the present disclosure. The communication processing according to the present technology is executed by the base station 20 that communicates with the terminal device.

[0089] The base station 20 generates a signal for the first to X-th physical channels (step S101). Moreover, the base station 20 can generate a plurality of signals. For example, the base station 20 can generate a signal for each of the plurality (X number) of physical channels or can generate a plurality of signals included in a single physical channel. Alternatively, the base station 20 can generate one or a plurality of signals included in each of the plurality of physical channels.

[0090] The base station 20 applies a first resource mapping to the plurality of signals (in this example, the signals of the first to X-th physical channels) to map the plurality of signals to a time resource or a logical resource (step S102). Through this process, the plurality of signals is multiplexed.

[0091] The base station 20 performs a Fourier transform (in this example, a discrete Fourier transform or a fast Fourier transform) on the plurality of signals to which the first resource mapping is applied, thereby generating a first transformed signal (step S103).

[0092] The base station 20 applies the second resource mapping to the first transformed signal to map the first transformed signal to a frequency resource and a time resource (step S104).

[0093] The base station 20 performs an inverse Fourier transform (in this example, an inverse fast Fourier transform (or an inverse discrete Fourier transform)) on the first transformed signal to which the second resource mapping is applied, thereby generating a second transformed signal (step S105).

[0094] The base station 20 performs downlink transmission by generating a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal and transmitting the signal to the terminal device (step S106).

[0095] The base station 20 according to the present technology multiplexes a plurality of signals using the first resource mapping to generate a downlink signal to which a single-carrier modulation scheme is applied. This makes it less likely that the plurality of signals will be arranged discontinuously in the frequency domain, enabling the base station 20 to further reduce PAPR.

[0096] In Patent Literature 1 mentioned above (Japanese Patent Laid-open Publication No. 2022-551796), a control channel transmission scheme is disclosed in the case where a single carrier is applied to a downlink signal. Patent Literature 1 (Japanese Patent Laid-open Publication No. 2022-551796) discloses a scheme for transmission using a first frequency resource for reference signal transmission and a second frequency resource for control channel transmission. In Patent Literature 1 (Japanese Patent Laid-open Publication No. 2022-551796), a resource mapping is performed only in the frequency domain, and techniques for performing a resource mapping in the time domain or logical domain are neither taught nor disclosed.

[0097] In Non-Patent Literature 1 (R1-1706156, "NR PSS and SSS Design", Intel Corporation, RAN1 #88bis, 7th April 2017) mentioned above, a technique is disclosed in which discrete Fourier transform (DFT) processing is applied to a downlink synchronization signal, and the resulting signal is mapped to a frequency resource. In Non-Patent Literature 1 (R1-1706156, "NR PSS and SSS Design", Intel Corporation, RAN1 #88bis, 7th April 2017), a technique is provided for single-carrier transmission of a single synchronization signal, but does not teach or disclose any technique related to multiplexing a plurality of signals.

[0098] As described above, in the present technique of the present disclosure, the base station 20 performs a first resource mapping to multiplex a plurality of signals before discrete Fourier transform (DFT) processing. This allows the base station 20 to further reduce PAPR.

[0099] Moreover, in the following embodiments, the base station 20 can be implemented not only as a terrestrial base station but also as a non-terrestrial base station 30 operating as a communication device such as a satellite station, a drone, a balloon, or an aircraft, or the like.

[0100] Further, in the following embodiments, some examples include specific values for the purpose of description, but such values are merely illustrative, and other values can be used instead.

[0101] In the embodiments herein, the term "resource" is construed to encompass 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), and the like.

[0102] Further, if the single-carrier scheme is not applied, the base station 20 transmits a downlink signal using, for example, a multi-carrier scheme. An example of the multi-carrier scheme is CP-OFDM. In addition, an example of the single-carrier scheme is DFT-S-OFDM. Moreover, CP-OFDM and DFT-S-OFDM are illustrative, and the multi-carrier scheme and the single-carrier scheme are not limited to CP-OFDM and DFT-S-OFDM, respectively.

[0103] As described above, in the case of the single-carrier scheme, transform precoding is applied during the transmission signal processing, whereas in the case of the multi-carrier scheme, transform precoding is not applied.

[0104] Thus, the processing related to the single-carrier scheme (DFT-S-OFDM) can be considered equivalent to processing to which transform precoding is applied. Furthermore, the processing related to the multi-carrier scheme (CP-OFDM) can be considered equivalent to processing to which transform precoding is not applied.

[0105] <<2. Configuration Example of Communication System>> <2-1. Overall Configuration Example of Communication System> Fig. 10 is a diagram illustrated to describe an example of the overall configuration of the communication system SYS1 according to an embodiment of the present disclosure. As illustrated in Fig. 10, the communication system SYS1 according to the present embodiment has the base station 20 and a plurality of terminal devices 50A and 50B.

[0106] Moreover, the communication system SYS1 can also include the management device 10, the non-terrestrial stations 30, and the relay stations 40 (see Fig. 2).

[0107] (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 operates in accordance with any wireless communication scheme, 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 illustrated) via a gateway device (not illustrated). In addition, the base station 20 can operate one or more beams identifiable by synchronization signal / PBCH block (SSB) and transmit and receive data to and from one or more terminal devices 50 via the beams.

[0108] Moreover, the base station 20 can be configured as a set of multiple physical or logical devices. For example, in the present embodiment, the base station 20 can be regarded as including a plurality of devices such as baseband unit (BBU) and RU, and can be considered as a collection of these multiple devices. Furthermore or alternatively, in the present embodiment, the base station 20 can include only the BBU, only the RU, or both. The BBU and the RU can be interconnected via a predetermined interface (e.g., eCPRI). Furthermore or alternatively, the RU can be referred to as a remote radio unit (RRU) or radio DoT (RD). Furthermore or alternatively, the RU can be compatible with the gNB-DU described later. Furthermore or alternatively, the BBU can be compatible with the gNB-CU described later. Alternatively, the RU can be connected to a gNB-DU described later. Furthermore, the BBU can be compatible with a combination of the gNB-CU and gNB-DU described later. Furthermore or alternatively, the RU can be a device formed integrally with an antenna. The antenna included in the base station 20 (e.g., an antenna formed integrally with the RU) can employ an advanced antenna system and can support MIMO (e.g., FD-MIMO) and beamforming. In the advanced antenna system, the antenna included in the base station 20 (e.g., an antenna formed integrally with the RU) can include, for example, 64 transmission antenna ports and 64 reception antenna ports.

[0109] Further, a plurality of base stations 20 can be interconnected. One or more base stations 20 can be included in a radio access network (RAN). In other words, the base station 20 can simply be referred to as a RAN, a RAN node, an access network (AN), or an AN node. In LTE, the RAN is referred to as enhanced universal terrestrial RAN (EUTRAN). In NR, the RAN is referred to as NG-RAN. In W-CDMA (UMTS), the RAN is referred to as UTRAN. The LTE base station 20 is referred to as evolved node B (eNodeB) or eNB. In other words, the EUTRAN includes one or more eNodeBs (eNBs). In addition, the NR base station 20 is referred to as gNodeB or gNB. In other words, the NG-RAN includes one or more gNBs. Furthermore, the EUTRAN can include a gNB (en-gNB) connected to a core network (EPC) in the LTE communication system (EPS). Similarly, the NG-RAN can include an ng-eNB connected to a core network 5GC in the 5G communication system (5GS). Furthermore or alternatively, in the case where the base station 20 is an eNB, gNB, and the like, the base station 20 can be referred to as a 3GPP access node. Furthermore or alternatively, if the base station 20 is a radio access point (e.g., a Wi-Fi (registered trademark) access point), the base station 20 can be referred to as a non-3GPP access node. Furthermore or alternatively, the base station 20 can be implemented as a remote radio head (RRH), which is a fiber extension device. Furthermore or alternatively, if the base station 20 is a gNB, the base station 20 can be referred to as a combination of a gNB-CU (central unit) and a gNB-DU (distributed unit) described above, or either of them. The gNB-CU hosts a plurality of upper layers of the access stratum (e.g., RRC, SDAP, and PDCP) for communication with the UE. On the other hand, the gNB-DU hosts a plurality of lower layers of the access stratum (e.g., RLC, MAC, and PHY). In other words, among the messages and information described later, RRC signalling (e.g., MIB, various SIBs including SIB1, RRCSetup message, RRCReconfiguration message) can be generated by the gNB-CU, while DCI and various physical channels (e.g., PDCCH and PBCH) described later can be generated by the gNB-DU. Alternatively, among the RRC signalling, some configurations (configuration information), such as IE:cellGroupConfig, can be generated by the gNB-DU, while the remaining configuration can be generated by the gNB-CU. These configurations (configuration information) can be transmitted and received via an F1 interface described later. The base station 20 can be configured to be capable of communicating with other base stations 20. For example, if multiple base stations 20 are eNBs or a combination of an eNB and an en-gNB, the base stations 20 can be interconnected via an X2 interface. Furthermore or alternatively, if multiple base stations 20 are gNBs or a combination of gn-eNBs and gNBs, the stations can be connected via an Xn interface. Furthermore or alternatively, if multiple base stations 20 are a combination of gNB-CU and gNB-DU, the stations can be connected via the F1 interface described above. Messages and information (such as RRC signalling, DCI information, and physical channel) described later can be communicated between multiple base stations 20 (e.g., via X2, Xn, and F1 interfaces).

[0110] Furthermore, as described above, the base station 20 can be configured to manage a plurality of cells C1. The cell C1 provided by the base station 20 is referred to as a serving cell. The serving cell can be a primary cell (PCell) or a secondary cell (SCell). In the case where dual connectivity (e.g., EUTRA-EUTRA dual connectivity, EUTRA-NR dual connectivity (ENDC), EUTRA-NR dual connectivity with 5GC, NR-EUTRA dual connectivity (NEDC), and NR-NR dual connectivity) is provided to a UE (e.g., the terminal device 50), the PCell and zero or a SCell or plurality of SCells provided by a master node (MN) are referred to as a master cell group. Furthermore, the serving cell can be a primary secondary cell or primary SCG cell (PSCell). In other words, in the case where dual connectivity is provided to a UE, the PSCell and zero or a SCell or plurality of SCells provided by a secondary node (SN) are referred to as a secondary cell group (SCG). Unless a special configuration (e.g., PUCCH on SCell) is applied, a physical uplink control channel (PUCCH) is transmitted on the PCell and PSCell, but not on the SCell. In addition, radio link failure is also detected for the PCell and PSCell, but not for the SCell (i.e., it is not necessarily detected). As described above, since the PCell and PSCell serve a special role among a serving cell or serving cells, they are also referred to as special cells (SpCells). One cell C1 can be associated with one downlink component carrier and one uplink component carrier. In addition, the system bandwidth corresponding to one cell C1 can be divided into a plurality of bandwidth parts. In such a case, one bandwidth part (BWP) or plurality of bandwidth parts can be configured in the UE, and one bandwidth part can be used by the UE as an Active BWP. In addition, the wireless resource (e.g., frequency band, numerology (subcarrier spacing), slot format (slot configuration)) available to the terminal devices 50 can differ for each cell C1, each component carrier, or each BWP.

[0111] The base station 20 uses, for example, a single-carrier scheme for downlink communication with the terminal devices 50.

[0112] The base station 20 can determine, for example, a signal waveform to be used for each of the terminal devices 50. In the example of Fig. 10, the base station 20 can select a multi-carrier signal to perform downlink communication S1 for the terminal device 50A located closer to the center of the cell C1. In addition, the base station 20 can select a single-carrier signal to perform downlink communication S2 for the terminal device 50B located closer to the edge of the cell C1.

[0113] In order to perform downlink communication with the terminal device 50B located closer to the edge of the cell, a larger transmission power is required, and lower PAPR is required. On the other hand, the required transmission power for the terminal device 50A located closer to the center of the cell C1 is lower compared to the edge of the cell, so it is easier to ensure the necessary transmission power even if PAPR is high.

[0114] Thus, the base station 20 selects, for example, a multi-carrier signal for the terminal device 50A located closer to the center of cell C1 and selects a single-carrier signal for the terminal device 50B located closer to the edge of the cell C1.

[0115] In this manner, the base station 20 allocates a single-carrier signal to downlink communication for which low PAPR is strictly required and allocates a signal waveform other than the single-carrier signal (in this example, a multi-carrier signal) to downlink communication for which the requirement for low PAPR is lenient. This enables the base station 20 to achieve low PAPR and improved efficiency of the entire system.

[0116] Moreover, although the example where the base station 20 determines the signal waveform depending on the position of the terminal devices 50 in the cell C1 has been described, the method of determining the signal waveform by the base station 20 is not limited to this example. In addition, the base station 20 can allocate the same signal waveform, such as allocating a single-carrier signal, to all the terminal devices 50 within the cell C1.

[0117] <2-2. Exemplary Configuration of Base Station> Fig. 11 is a block diagram illustrating an exemplary configuration of the base station 20 according to an embodiment of the present disclosure. As illustrated in Fig. 11, the base station 20 includes a higher-layer processing unit 101, a control unit 103, a reception unit 105, a transmission unit 107, and a transmission and reception antenna 109.

[0118] The base station 20 can support one or more radio access technologies (RATs). For example, the base station 20 can support both LTE and NR. In such a case, some or all of the components included in the base station 20 can be configured individually for each RAT. For example, the reception unit 105 and the transmission unit 107 can be configured separately for LTE and NR.

[0119] Further, in an NR cell, some or all of the components included in the base station 20 illustrated in Fig. 11 can be configured individually depending on a parameter set related to a transmission signal. For example, in a specific NR cell, a wireless reception unit 1057 and a wireless transmission unit 1077 can be configured individually depending on a parameter set related to a transmission signal.

[0120] (Higher-Layer Processing Unit) The higher-layer processing unit 101 outputs downlink data (transport block) to the control unit 103. The higher-layer processing unit 101 performs processing of a medium access control (MAC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a radio resource control (RRC) layer. In addition, the higher-layer processing unit 101 generates control information used to control the reception unit 105 and the transmission unit 107, and outputs the control information to the control unit 103.

[0121] The higher-layer processing unit 101 performs and manages processing related to RAT control, radio resource control, subframe configuration, scheduling control, and / or CSI reporting control. The processing and management in the higher-layer processing unit 101 is performed for each of the terminal devices 50, or commonly for all the terminal devices 50 connected to the base station 20.

[0122] The processing and management performed by the higher-layer processing unit 101 can be carried out solely by the higher-layer processing unit 101, or can be acquired from a higher-level node or another base station 20. In addition, the processing and management performed in the higher-layer processing unit 101 can be executed individually depending on the RAT. For example, the higher-layer processing unit 101 performs processing and management specific to LTE and processing and management specific to NR separately.

[0123] In the RAT control performed by the higher-layer processing unit 101, management related to the RAT is carried out. For example, the RAT control involves management regarding LTE and / or management regarding NR. The management regarding NR includes the configuration and processing of the parameter set related to transmission signals in an NR cell.

[0124] In the radio resource control performed by the higher-layer processing unit 101, the configuration information for the base station is managed. The radio resource control performed by the higher-layer processing unit 101 includes generation and / or management of downlink data (transport block), system information, RRC message (RRC parameter), and / or MAC control element (CE).

[0125] In the subframe configuration performed by the higher-layer processing unit 101, management of subframe configuration, subframe pattern configuration, uplink-downlink configuration, uplink reference UL-DL configuration, and / or downlink reference UL-DL configuration is performed.

[0126] Moreover, the subframe configuration by the higher-layer processing unit 101 is also referred to as base station subframe configuration. In addition, the subframe configuration by the higher-layer processing unit 101 is capable of being determined based on the uplink and downlink traffic volumes.

[0127] Further, the subframe configuration by the higher-layer processing unit 101 is capable of being determined based on the scheduling result of the scheduling control performed by the higher-layer processing unit 101.

[0128] In the scheduling control performed by the higher-layer processing unit 101, parameters, such as the frequency and subframe to which a physical channel is to be allocated, the coding rate and modulation scheme of the physical channel, and the transmission power, are determined, based on the received channel state information and the estimated value of the propagation path or channel quality information input from a channel measurement unit 1059. For example, the control unit 103 generates control information (DCI format) based on the scheduling result of the scheduling control performed by the higher-layer processing unit 101.

[0129] In CSI reporting control performed by the higher-layer processing unit 101, the CSI reporting by the terminal devices 50 is controlled. For example, the configuration of a CSI reference resource to be assumed for CSI calculation by the terminal devices 50 is controlled.

[0130] (Control Unit) The control unit 103 controls the reception unit 105 and the transmission unit 107 based on the control information from the higher-layer processing unit 101. The control unit 103 generates control information for the higher-layer processing unit 101 and outputs the control information to the higher-layer processing unit 101.

[0131] The control unit 103 receives a decoded signal from a decoding unit 1051 and a channel estimation result from the channel measurement unit 1059 as input. The control unit 103 outputs a signal to be encoded to an encoding unit 1071. In addition, the control unit 103 is used to control the entirety or a portion of the base station 20.

[0132] Further, the control unit 103 determines a signal waveform to be used for downlink communication with the terminal devices 50 (hereinafter also referred to as a "signal waveform to be used") from among the single-carrier signal and the multi-carrier signal.

[0133] The control unit 103 controls the transmission unit 107 to notify the terminal devices 50 of information regarding the signal waveform to be used using a predetermined signal waveform (e.g., a single-carrier signal). In addition, the control unit 103 controls the transmission unit 107 to perform downlink communication with the terminal devices 50 using the notified signal waveform to be used.

[0134] (Reception Unit) 　The reception unit 105, under the control of the control unit 103, receives a signal transmitted from the terminal devices 50 via the transmission and reception antenna 109 and further performs reception processing such as separation, demodulation, and decoding, and then outputs the processed information to the control unit 103.

[0135] Moreover, the reception processing in the reception unit 105 is performed based on a predefined configuration or a configuration notified by the base station 20 to the terminal device 50.

[0136] The reception unit 105 includes the decoding unit 1051, a demodulation unit 1053, a demultiplexing unit 1055, the wireless reception unit 1057, and the channel measurement unit 1059.

[0137] (Wireless Reception Unit) The wireless reception unit 1057 performs processing on the uplink signal received via the transmission and reception antenna 109, including conversion to an intermediate frequency (down-conversion), removal of unnecessary frequency component, control of amplification level to maintain a proper signal level, quadrature demodulation based on in-phase and quadrature components of the received signal, conversion from an analog signal to a digital signal, removal of guard interval (GI), and / or extraction of a frequency-domain signal using fast Fourier transform (FFT).

[0138] (Demultiplexing Unit) The demultiplexing unit 1055 separates an uplink channel such as PUCCH or PUSCH and / or an uplink reference signal from the signal input from the wireless reception unit 1057. The demultiplexing unit 1055 outputs the uplink reference signal to the channel measurement unit 1059. The demultiplexing unit 1055 performs channel compensation for the uplink channel based on a propagation path estimation value input from the channel measurement unit 1059.

[0139] (Demodulation Unit) The demodulation unit 1053 demodulates a modulation symbol of an uplink channel using a modulation scheme such as binary phase shift keying (BPSK), π / 2-BPSK, quadrature phase shift keying (QPSK), quadrature amplitude modulation (16QAM), 64QAM, or 256QAM. The demodulation unit 1053 performs separation and demodulation of an uplink channel multiplexed by MIMO.

[0140] (Decoding Unit) The decoding unit 1051 performs decoding processing on the encoded 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 the decoding processing on the PUSCH for each transport block.

[0141] (Channel Measurement Unit) The channel measurement unit 1059 measures an estimation value of the propagation path and / or channel quality, or the like, from the uplink reference signal input from the demultiplexing unit 1055, and outputs the result to the demultiplexing unit 1055 and / or the control unit 103. For example, the channel measurement unit 1059 measures an estimation value of the propagation path for performing propagation path compensation for PUCCH or PUSCH using UL-DMRS, and measures the channel quality in the uplink using SRS.

[0142] (Transmission Unit) The transmission unit 107 performs transmission processing such as encoding, modulation, and multiplexing on the downlink control information and downlink data received from the higher-layer processing unit 101 under the control of the control unit 103. For example, the transmission unit 107 generates and multiplexes PHICH, PDCCH, EPDCCH, PDSCH, and a downlink reference signal to generate a transmission signal.

[0143] Moreover, the transmission processing in the transmission unit 107 is performed based on a predefined configuration, a configuration notified by the base station 20 to the terminal devices 50, or a configuration notified through the PDCCH or EPDCCH transmitted in the same subframe.

[0144] The transmission unit 107 includes the encoding unit 1071, a modulation unit 1073, a multiplexing unit 1075, the wireless transmission unit 1077, and a downlink reference signal generation unit 1079.

[0145] (Encoding Unit) The encoding unit 1071 encodes an HARQ indicator (HARQ-ACK), downlink control information, and downlink data received from the control unit 103 using a predetermined encoding scheme such as block coding, convolutional coding, or turbo coding.

[0146] (Modulation Unit) The modulation unit 1073 modulates the encoded bits received from the encoding unit 1071 using a predetermined modulation scheme such as BPSK, π / 2-BPSK, QPSK, 16QAM, 64QAM, or 256QAM.

[0147] (Downlink Reference Signal Generation Unit) The downlink reference signal generation unit 1079 generates a downlink reference signal based on a physical cell identification (PCI), an RRC parameter configured for the terminal devices 50, and the like.

[0148] (Multiplexing Unit) The multiplexing unit 1075 multiplexes the modulation symbols of each channel and the downlink reference signal and maps them to a predetermined resource element. In the case where downlink communication using the second signal waveform (single-carrier signal) is performed, the multiplexing unit 1075 performs, for example, a first resource mapping, and maps a plurality of signals to a time resource or a logical resource. In addition, the multiplexing unit 1075 performs a fast Fourier transform or a discrete Fourier transform on the plurality of mapped signals. The multiplexing unit 1075 performs the second resource mapping on the signal that has been subjected to the fast Fourier transform or the discrete Fourier transform.

[0149] (Wireless Transmission Unit) The wireless transmission unit 1077 performs processing on a signal from the multiplexing unit 1075, including conversion to a time domain signal by an inverse fast Fourier transform (IFFT), addition of a guard interval, and generation of a baseband digital signal. In addition, the wireless transmission unit 1077 performs processing including 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 from the wireless transmission unit 1077 is transmitted from the transmission and reception antenna 109.

[0150] In this regard, the wireless transmission unit 1077 according to the present embodiment is capable of supporting a plurality of downlink signal waveforms. With reference to Figs. 12 to 14, a detailed description will be given of the wireless transmission unit 1077 of the base station 20 that supports both a first signal waveform (multi-carrier signal) and a second signal waveform (single-carrier signal).

[0151] Fig. 12 is a block diagram illustrating an exemplary 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.

[0152] The signal waveform switching unit 401 switches the downlink communication to be transmitted between the first signal waveform and the second signal waveform in accordance with a predetermined condition or situation.

[0153] In the case where the downlink communication to be transmitted uses the first signal waveform, the downlink communication is subjected to transmission processing by the first signal waveform transmission unit 403. In the case where the downlink communication to be transmitted uses the second signal waveform, the downlink communication is subjected to transmission processing by the second signal waveform transmission unit 405. The condition and situation for switching in the signal waveform switching unit 401 will be described later.

[0154] Moreover, the signal waveform switching unit 401 is also referred to as a signal waveform control unit. In addition, although Fig. 12 illustrates the first signal waveform transmission unit 403 and the second signal waveform transmission unit 405 as separate processing units, they can be implemented as a single processing unit in which only part of the transmission processing is switched.

[0155] Fig. 13 is a block diagram illustrating an exemplary configuration of the 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 the downlink channel and signal to be transmitted using CP-OFDM as a signal waveform for uplink communication. The first signal waveform transmission unit 403 includes an S / P unit 4031, an inverse discrete Fourier transform (IDFT) unit 4033, a P / S unit 4035, and a CP insertion unit 4037.

[0156] The S / P unit 4031 converts an input serial signal into a parallel signal of size M. The size M is herein determined depending on the size of the frequency domain resource used for the downlink communication. The parallel signal of size M is input to the IDFT unit 4033 such that it corresponds to a predetermined frequency domain.

[0157] The IDFT unit 4033 performs inverse Fourier transform processing on the parallel signal of size N. In this description, in the case where the size N is a power of two, the Fourier transform processing can be used as inverse fast Fourier transform (IFFT) processing. The P / S unit 4035 converts the parallel signal of size N into a serial signal. The CP insertion unit 4037 inserts a predetermined CP for each OFDM symbol.

[0158] Fig. 14 is a block diagram illustrating an exemplary configuration of the second signal waveform transmission unit 405 according to an embodiment of the present disclosure. The second signal waveform transmission unit 405 performs transmission processing on the downlink channel and the signal to be transmitted using, for example, DFT-S-OFDM as a signal waveform for downlink communication.

[0159] 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 on a parallel signal of size M. The size M is herein determined depending on the size of the frequency domain resource used for the downlink communication. The parallel signal of size M is input to the IDFT unit 4053 such that it corresponds to a predetermined frequency domain.

[0160] The IDFT unit 4053 performs inverse Fourier transform processing on a parallel signal of size N. In this description, if the size N is a power of two, the Fourier transform processing can be used as the IFFT processing. The P / S unit 4055 converts the parallel signal of size N into a serial signal. The CP insertion unit 4057 inserts a predetermined CP for each DFT-S-OFDM symbol.

[0161] <2-3. Exemplary Configuration of Terminal Device> Next, the configuration of the terminal devices 50 will be described. The terminal devices 50 can also be referred to as user equipment (UE) 50.

[0162] The terminal devices 50 is are communication device that performs wireless communication with other communication devices such as the base station 20. The terminal devices 50 can be, for example, a mobile phone, a smart device (smartphone or tablet), a personal digital assistant (PDA), or a personal computer. Additionally, the terminal devices 50 can be a device such as a professional-use camera equipped with communication functionality, or a motorcycle or a mobile relay vehicle equipped with a communication device such as a field pickup unit (FPU). The terminal devices 50 can be a machine-to-machine (M2M) device or an Internet of things (IoT) device.

[0163] Moreover, the terminal devices 50 can be capable of NOMA communication with the base station 20. In addition, the terminal devices 50 can be capable of supporting an automatic retransmission technique such as HARQ when communicating with the base station 20. The terminal devices 50 can be capable of sidelink communication with other terminal devices 50. The terminal devices 50 can also be capable of supporting an automatic retransmission technique such as HARQ when performing sidelink communication. Moreover, the terminal devices 50 can be capable of supporting NOMA communication even in communication (sidelink) with other terminal devices 50. In addition, the terminal devices 50 can be capable of supporting LPWA communication with other communication devices (e.g., the base station 20 or other terminal devices 50). Furthermore, the wireless communication used by the terminal devices 50 can be wireless communication using millimeter waves. Moreover, the wireless communication used by the terminal devices 50 (including sidelink communication) can be wireless communication using radio waves, or wireless communication using infrared rays or visible light (optical wireless).

[0164] Further, the terminal devices 50 can be mounted on a mobile device. The mobile device refers to a movable wireless communication device. For example, the terminal devices 50 can 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 such a vehicle. Moreover, the mobile device can be a mobile terminal, or a mobile device that moves on land (strictly speaking, the ground), underground, on water, or underwater. In addition, the mobile device can be a mobile device that moves within the atmosphere, such as a drone or a helicopter, or can be a mobile device that moves outside the atmosphere, such as an artificial satellite.

[0165] The terminal devices 50 can simultaneously connect to and communicate with a plurality of base stations 20 or a plurality of cells. For example, in the case where a single base station 20 supports a communication area through a plurality of cells (e.g., pCell and sCell), it is possible for the base station 20 and the terminal devices 50 to communicate by bundling these multiple cells using carrier aggregation (CA) technology, dual connectivity (DC) technology, or multi-connectivity (MC) technology. Alternatively, it is also possible for the terminal devices 50 and the plurality of base stations 20 to communicate through cells of different base stations 20 using coordinated multi-point transmission and reception (CoMP) technology.

[0166] Fig. 15 is a block diagram illustrating an exemplary configuration of one of the terminal devices 50 according to an embodiment of the present disclosure. As illustrated in Fig. 15, the terminal device 50 includes a higher-layer processing unit 201, a control unit 203, a reception unit 205, a transmission unit 207, and a transmission and reception antenna 209.

[0167] The terminal device 50 can support one or more RATs. For example, the terminal device 50 can support both LTE and NR. In such a case, some or all of the components included in the terminal device 50 can be individually configured depending on the RAT. For example, the reception unit 205 and the transmission unit 207 are individually configured for LTE and NR. In addition, in an NR cell, some or all of the components included in the terminal device 50 illustrated in Fig. 15 can be individually configured depending on a parameter set related to a transmission signal. For example, in a specific NR cell, a wireless reception unit 2057 and a wireless transmission unit 2077 can be individually configured depending on a parameter set related to a transmission signal.

[0168] (Higher-Layer Processing Unit) The higher-layer processing unit 201 outputs uplink data (transport block) to the control unit 203. The higher-layer processing unit 201 performs processing of a media access control layer, a packet data convergence protocol layer, a radio link control layer, and a radio resource control layer. In addition, the higher-layer processing unit 201 generates control information used to control the reception unit 205 and the transmission unit 207, and outputs the control information to the control unit 203.

[0169] The higher-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 higher-layer processing unit 201 are performed based on a predefined configuration and / or a configuration based on control information configured or notified by the base station 20.

[0170] For example, the control information from the base station 20 includes an RRC parameter, an MAC control element, or DCI. In addition, the processing and management by the higher-layer processing unit 201 can be performed independently depending on the RAT. For example, the higher-layer processing unit 201 performs processing and management specific to LTE and specific to NR independently.

[0171] In the RAT control by the higher-layer processing unit 201, management related to the RAT is performed. For example, the RAT control involves management regarding LTE and / or management regarding NR. The management regarding NR includes the configuration and processing of the parameter set related to transmission signals in an NR cell.

[0172] In the radio resource control by the higher-layer processing unit 201, management of configuration information in the terminal device is performed. The radio resource control by the higher-layer processing unit 201 includes generation and / or management of uplink data (transport block), system information, RRC message (RRC parameter), and / or MAC control element (CE).

[0173] In the subframe configuration by the higher-layer processing unit 201, the subframe configuration of the base station 20 and / or another base station different from the base station 20 is managed. The subframe configuration includes uplink or downlink configuration for the subframe, subframe pattern configuration, uplink-downlink configuration, uplink reference UL-DL configuration, and / or downlink reference UL-DL configuration. Moreover, the subframe configuration by the higher-layer processing unit 201 is also referred to as terminal subframe configuration.

[0174] In the scheduling control by the higher-layer processing unit 201, control information used for controlling the scheduling of the reception unit 205 and the transmission unit 207 is generated based on DCI (scheduling information) from the base station 20.

[0175] In the CSI reporting control by the higher-layer processing unit 201, control related to the reporting of CSI to the base station 20 is performed. For example, in the CSI reporting control, the configuration of the CSI reference resource to be assumed for calculating the CSI in a channel measurement unit 2059 is controlled. In the CSI reporting control, a resource (timing) used for reporting CSI is controlled based on a DCI and / or RRC parameter.

[0176] (Control Unit) The control unit 203 controls the reception unit 205 and the transmission unit 207 based on the control information from the higher-layer processing unit 201. The control unit 203 generates control information for the higher-layer processing unit 201 and outputs the control information to the higher-layer processing unit 201. The control unit 203 receives as input a decoded signal from a decoding unit 2051 and a channel estimation result from the channel measurement unit 2059. The control unit 203 outputs the signal to be encoded to an encoding unit 2071. Additionally, the control unit 203 can also be used to control the entirety or a portion of the terminal device 50.

[0177] Further, the control unit 203 acquires information regarding the signal waveform used for downlink communication with the base station 20 from the base station 20 via the reception unit 205, among the single-carrier signal and the multi-carrier signal. Moreover, the information regarding the signal waveform to be used is information to be transmitted in a predetermined signal waveform (e.g., a single-carrier signal). The control unit 203 controls the reception unit 205 to perform downlink communication with the base station 20 in the signal waveform to be used.

[0178] (Reception Unit) The reception unit 205, under the control of the control unit 203, receives a signal transmitted from the base station 20 via the transmission and reception antenna 209, performs reception processing such as separation, demodulation, and decoding, and outputs the processed information to the control unit 203. Moreover, the reception processing in the reception unit 205 is performed based on a predetermined configuration, or a notification or configuration from the base station 20. The reception unit 205 includes a decoding unit 2051, a demodulation unit 2053, a demultiplexing unit 2055, a wireless reception unit 2057, and a channel measurement unit 2059.

[0179] (Wireless Reception Unit) The wireless reception unit 2057 performs conversion to an intermediate frequency (down-conversion), removal of unnecessary frequency components, and control of the amplification level so that the signal level is appropriately maintained for the uplink signal received via the transmission and reception antenna 209. Additionally, the wireless reception unit 2057 performs quadrature demodulation based on the in-phase and quadrature components of the received signal, conversion from an analog signal to a digital signal, removal of the guard interval, and / or extraction of the frequency-domain signal by fast Fourier transform.

[0180] In this description, the wireless reception unit 2057 according to the present embodiment is capable of supporting a plurality of uplink signal waveforms. With reference to Figs. 16 to 18, a detailed description will be given of the wireless reception 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).

[0181] Fig. 16 is a block diagram illustrating an exemplary configuration of the wireless reception unit 2057 according to an embodiment of the present disclosure. The wireless reception unit 2057 includes a signal waveform switching unit 301, a first signal waveform reception unit 303, and a second signal waveform reception unit 305.

[0182] The signal waveform switching unit 301 switches between the first signal waveform and the second signal waveform for the received downlink communication depending on predetermined condition and situation. If the received downlink communication is the first signal waveform, the downlink communication is received and processed by the first signal waveform reception unit 303. If the received downlink communication is the second signal waveform, the downlink communication is received and processed by the second signal waveform reception unit 305.

[0183] Moreover, although Fig. 16 illustrates the first signal waveform reception unit 303 and the second signal waveform reception unit 305 as different processing units, but they can alternatively be implemented as a single processing unit in which only a portion of the reception processing is switched.

[0184] Fig. 17 is a block diagram illustrating an exemplary configuration of the first signal waveform reception unit 303 according to an embodiment of the present disclosure. The first signal waveform reception unit 303 performs reception processing on the downlink channel and signals transmitted using CP-OFDM as a signal waveform for downlink communication. The first signal waveform reception unit 303 includes a CP removal unit 3031, an S / P unit 3033, a DFT unit 3035, and a P / S unit 3037.

[0185] The CP removal unit 3031 removes the cyclic prefix (CP) appended 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 a power of two, the Fourier transform processing can be implemented as FFT processing.

[0186] The P / S unit 3037 converts an input parallel signal of size M into a serial signal. In this description, the P / S unit 3037 receives a downlink communication signal transmitted by the terminal device 50 that performs the reception processing. The size M is determined depending on the size of the frequency domain resource used for the downlink communication.

[0187] Fig. 18 is a block diagram illustrating an exemplary configuration of the second signal waveform reception unit 305 according to an embodiment of the present disclosure. The second signal waveform reception unit 305 performs reception processing on the downlink channel and signals transmitted using, for example, DFT-S-OFDM as the signal waveform of the downlink communication. The second signal waveform reception unit 305 includes a CP removal unit 3051, an S / P unit 3053, a DFT unit 3055, and an IDFT unit 3057.

[0188] The CP removal unit 3051 removes a CP added to the received downlink communication. The S / P unit 3053 converts an input serial signal into a parallel signal of size N. The DFT unit 3055 performs Fourier transform processing. Here, if the size N is a power of two, the Fourier transform processing can be implemented as FFT processing.

[0189] The IDFT unit 3057 performs inverse Fourier transform processing on the input signal of size M. In particular, the IDFT unit 3057 receives a downlink communication signal transmitted by the terminal device 50 that performs reception processing. The size M is determined depending on the size of the frequency domain resource used for the downlink communication.

[0190] (Demultiplexing Unit) Referring back to Fig. 15, the demultiplexing unit 2055 separates downlink channels such as PHICH, PDCCH, EPDCCH, or PDSCH, downlink synchronization signals, and / or downlink reference signals from the signals input from the wireless reception unit 2057.

[0191] In the case where downlink communication using the second signal waveform (single-carrier signal) is performed, the demultiplexing unit 2055 performs, for example, the first resource de-mapping to separate a plurality of signals from the downlink communication signal.

[0192] The demultiplexing unit 2055 outputs the downlink reference signal to the channel measurement unit 2059. The demultiplexing unit 2055 performs the propagation path compensation for the downlink channel based on the propagation path estimation value that is input from the channel measurement unit 2059.

[0193] (Demodulation Unit) The demodulation unit 2053 demodulates the received signal using a modulation scheme such as BPSK, π / 2-BPSK, QPSK, 16QAM, 64QAM, or 256QAM for the modulation symbols of the downlink channel. The demodulation unit 2053 performs separation and demodulation of the MIMO-multiplexed downlink channel.

[0194] (Decoding Unit) The decoding unit 2051 performs decoding processing on the encoded 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 for the PDSCH on a transport block basis.

[0195] (Channel Measurement Unit) The channel measurement unit 2059 measures the propagation path estimation value and / or channel quality based on the downlink reference signal that is input from the demultiplexing unit 2055 and outputs the result to the demultiplexing unit 2055 and / or the control unit 203.

[0196] The downlink reference signal used for measurement by the channel measurement unit 2059 can be determined based on at least the transmission mode that is set by the RRC parameter and / or other RRC parameters.

[0197] For example, DL-DMRS is used to measure the propagation path estimation value for performing propagation path compensation for the PDSCH or EPDCCH. The CRS is used to measure the propagation path estimation value for performing propagation path compensation for the PDCCH or PDSCH, and / or to measure the downlink channel for reporting CSI. The CSI-RS is used to measure the downlink channel for reporting CSI.

[0198] The channel measurement unit 2059 calculates reference signal received power (RSRP) and / or reference signal received quality (RSRQ) based on the CRS, CSI-RS, or detection signal, and outputs the result to the higher-layer processing unit 201.

[0199] (Transmission Unit) The transmission unit 207 performs transmission processing such as encoding, modulation, and multiplexing on the uplink control information and uplink data input from the higher-layer processing unit 201 under the control of the control unit 203. For example, the transmission unit 207 generates and multiplexes an uplink channel such as PUSCH or PUCCH and / or an uplink reference signal to generate a transmission signal.

[0200] Moreover, the transmission processing by the transmission unit 207 is performed based on a predefined configuration or a configuration or notification from the base station 20. The transmission unit 207 includes an encoding unit 2071, a modulation unit 2073, a multiplexing unit 2075, a wireless transmission unit 2077, and an uplink reference signal generation unit 2079.

[0201] (Encoding Unit) The encoding unit 2071 encodes an HARQ indicator (HARQ-ACK), uplink control information, and uplink data input from the control unit 203 using a predetermined encoding scheme such as block encoding, convolutional encoding, or turbo encoding.

[0202] (Modulation Unit) The modulation unit 2073 modulates the encoded bits input from the encoding unit 2071 using a predetermined modulation scheme such as BPSK, π / 2-BPSK, QPSK, 16QAM, 64QAM, or 256QAM.

[0203] (Uplink Reference Signal Generation Unit) The uplink reference signal generation unit 2079 generates an uplink reference signal based on the RRC parameter configured for the terminal device 50.

[0204] (Multiplexing Unit) The multiplexing unit 2075 multiplexes the modulation symbols of each channel and the uplink reference signal, and maps them to a specified resource element.

[0205] (Wireless Transmission Unit) The wireless transmission unit 2077 performs conversion of the signal from the multiplexing unit 2075 into a time domain signal via inverse fast Fourier transform, addition of a guard interval, generation of a baseband digital signal, conversion to an analog signal, and orthogonal modulation. The wireless transmission unit 2077 further performs conversion 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 wireless transmission unit 2077 is transmitted via the transmission and reception antenna 209.

[0206] <<3. Example of Processing in Communication System>> <3-1. Example of Communication Processing> Fig. 19 is a sequence diagram illustrating the communication processing procedure for downlink communication according to an embodiment of the present disclosure. The communication processing illustrated in Fig. 19 is executed by the communication system SYS1, for example, in a case where a downlink signal to which a single-carrier modulation scheme is applied is transmitted by the communication system SYS1.

[0207] As illustrated in Fig. 19, the base station 20 applies a first resource mapping to a plurality of signals, and maps and multiplexes the plurality of signals to the time resource or logical resource (step S201).

[0208] The base station 20 performs DFT processing (or FFT processing) on the plurality of signals mapped to the time resource or logical resource to generate a DFT signal (an example of a first transformed signal) (step S202).

[0209] The base station 20 applies the second resource mapping to the DFT signal and maps the DFT signal to a frequency resource and a time resource (step S203).

[0210] The base station 20 performs IFFT processing on the DFT signal mapped to the frequency resource and the time resource to generate an IFFT signal (an example of a second transformed signal) (step S204).

[0211] The base station 20 transmits control information including mapping information related to the first resource mapping and the second resource mapping to the terminal device 50 (step S205). The base station 20 transmits the mapping information using, for example, DCI or the like.

[0212] The base station 20 generates a downlink signal from the IFFT signal and transmits the downlink signal to the terminal device 50 (step S206).

[0213] The terminal device 50 decodes the received downlink signal (step S207).

[0214] <3-2. Example of Signal Processing> Fig. 20 is a diagram illustrating an example of signal processing for downlink communication according to an embodiment of the present disclosure. In Fig. 20, an example of signal processing is illustrated where a single-carrier signal is transmitted from the base station 20 to the terminal device 50 as a downlink signal.

[0215] Here, signal processing in which the base station 20 performs the first resource mapping on a plurality of signals is illustrated. Signal processing for a case where the first resource mapping is not performed, such as when there is only one signal to be transmitted, is the same as in Fig. 1, so the description here is omitted.

[0216] As illustrated in Fig. 20, an error correction parity bit is added to the transmission signal sequence by error correction coding (channel coding). Subsequently, rate matching extracts a number of bits corresponding to a transmission resource and a modulation scheme from the transmission signal sequence. Interleaving and scrambling are applied to the extracted bits.

[0217] Then, the bit sequence is mapped to a complex constellation point through modulation processing. In the case of performing transmission using a plurality of layers, the bit sequence is mapped to complex constellation points in each layer. In such processing, for example, a plurality of signals is generated.

[0218] In this regard, in the present embodiment, the first resource mapping is performed as illustrated in Fig. 20.

[0219] Next, discrete Fourier transformation (DFT) processing, also referred to as transform precoding, is performed on the signal subjected to the first resource mapping. Moreover, the processing at this stage, i.e., the DFT processing performed at this stage, can be referred to by a name other than transform precoding. Additionally, in OFDM transmission, the transform precoding processing is omitted.

[0220] Thereafter, a transmission weight is applied by precoding, and after the second resource mapping is performed, the frequency domain transmission signal is transformed into a time-domain transmission signal (time-axis signal) by OFDM processing, which is transmitted. Since the processing in Fig. 20 is for downlink communication, the time-domain transmission signal is transmitted from the base station 20 to the terminal device 50.

[0221] Moreover, in this example, precoding is performed before the second resource mapping, but precoding can alternatively be performed after the second resource mapping, or precoding can be omitted.

[0222] On the receiving side, the received signal in the time domain is first transformed into a signal in the frequency-domain signal (frequency-axis signal) through OFDM processing. Then, the second resource de-mapping is performed, followed by frequency equalization processing (equalizer) is performed to compensate for distortion due to radio wave propagation.

[0223] The inverse discrete Fourier transformation (IDFT) processing, referred to as transform de-precoding, is performed. Subsequently, the first resource de-mapping processing is performed.

[0224] Thereafter, signals mapped to a plurality of layers are demapped, and a soft decision is made on each bit from the complex constellation point. The bit values obtained through the soft-decision processing are subjected to de-scrambling, de-interleaving, de-rate matching, and channel decoding to obtain a reception signal sequence.

[0225] <<4. Example of Signal Multiplexing>> The following describes an example of multiplexing a specific signal. The signals exemplified herein are merely illustrative and signals other than those described below can be multiplexed according to the present technology.

[0226] As described above, in the present embodiment, the base station 20 performs a first resource mapping to map a plurality of signals to the time resource or logical resource.

[0227] The time resource herein is, for example, a resource that is indicated by the relative time of the signal, such as being transmitted earlier or later, rather than the absolute time.

[0228] The logical resource can be defined, for example, as a value ranging from zero to (maximum value of predetermined size - 1) in a predetermined size. For example, the predetermined size can be specified as any of the following. Alternatively, the predetermined size is not limited to the following examples and can be a size defined by another size (value). -Bandwidth of bandwidth part -Bandwidth of component carrier -FFT size -Size notified in advance by base station 20 -Size statically determined in specifications, or the like

[0229] The logical resource can be referred to by other names. For example, the logical resource can also be referred to as logical resources, virtual resources, virtual resources, logical resource blocks, virtual resource blocks, virtual resource blocks, virtual resource blocks, or the like. Alternatively, the logical resource can have other designations not listed herein.

[0230] <4-1. Example of Multiplexing Signal of Multiple Physical Channels> An example is now described in which the base station 20 multiplexes signals transmitted on each of a plurality of different physical channels.

[0231] <4-1-1. Synchronization Signal and / or System Information> An example is now described in which the base station 20 multiplexes signals corresponding to at least one of a synchronization signal, system information, and a reference signal.

[0232] (Multiple Synchronization Signals) Fig. 21 is a diagram illustrating an example of multiplexing synchronization signals according to an embodiment of the present disclosure. In Fig. 21, the processing from when the base station 20 performs the first resource mapping and maps the signal to a time or logical resource up to when it executes the IFFT processing.

[0233] In Fig. 21, an example is illustrated in which a PSS and an SSS are multiplexed as the synchronization signal, but the synchronization signal to be multiplexed is not limited to the PSS and SSS. For example, the synchronization signal can be consecutively arranged synchronization signal to which a modulation scheme capable of reducing PAPR (e.g., low-order modulation) is applied.

[0234] The base station 20 performs resource mapping of the PSS and SSS to a time or logical resource (time resource or logical resource) (corresponding to the first resource mapping). Then, the base station 20 applies DFT processing (e.g., transform precoding) collectively to the mapped PSS and SSS to generate a DFT signal including the PSS and SSS.

[0235] The base station 20 maps the DFT signal (PSS / SSS) to frequency and time resources (corresponding to the second resource mapping). The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (OFDM baseband signal) including the PSS and SSS.

[0236] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0237] Note that, although the example herein is illustrated in which the base station 20 multiplexes two synchronization signals (e.g., PSS and SSS), the number of multiplexed synchronization signals is not limited to two. The base station 20 can multiplex three or more synchronization signals.

[0238] In this way, by collecting (multiplexing) and applying DFT processing to a plurality of synchronization signals, it is possible for the base station 20 to reduce the number of times the DFT processing is applied while reducing PAPR.

[0239] (Synchronization Signal and System Information) Fig. 22 is a diagram illustrating an example of multiplexing a synchronization signal and system information according to an embodiment of the present disclosure. Fig. 22 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to a time or logical resource up to when it executes the IFFT processing.

[0240] Fig. 22 illustrates an example in which PSS and SSS are multiplexed as synchronization signals, and information transmitted on PBCH is multiplexed as system information. Note that the multiplexed synchronization signals are not limited to PSS and SSS. For example, the synchronization signal can be consecutively arranged synchronization signal to which a modulation scheme capable of reducing PAPR (e.g., low-order modulation) is applied.

[0241] The base station 20 performs resource mapping of the PSS, SSS, and system information (PBCH) to the time or logical resource (time resource or logical resource) (corresponding to the first resource mapping). Then, the base station 20 applies DFT processing (e.g., transform precoding) to the mapped PSS, SSS, and system information collectively to generate a DFT signal including the PSS, SSS, and system information.

[0242] The base station 20 maps the DFT signal (PSS / SSS / PBCH) to the frequency and time resource (corresponding to the second resource mapping). The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (OFDM baseband signal) including the PSS, SSS, and system information (PBCH).

[0243] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0244] Note that, although the example herein is illustrated in which the base station 20 multiplexes two synchronization signals (e.g., PSS and SSS), the number of multiplexed synchronization signals is not limited to two. The base station 20 can multiplex three or more synchronization signals. Furthermore, the base station 20 can multiplex multiple pieces of system information in addition to or instead of the synchronization signal.

[0245] As described above, it is possible for the base station 20 to reduce the number of times that the DFT processing is applied while reducing PAPR by collecting (multiplexing) a plurality of synchronization signals and system information and applying the DFT processing.

[0246] (System Information and Reference Signal) Fig. 23 is a diagram illustrating an example of multiplexing system information and a reference signal according to an embodiment of the present disclosure. Fig. 23 illustrates the processing from when the base station 20 performs the first resource mapping and maps a signal to the time or logical resource up to when it performs IFFT processing.

[0247] Fig. 23 illustrates an example in which information transmitted on the PBCH as system information and a signal used for decoding the system information (e.g., DMRS) as a reference signal are multiplexed. Moreover, the system information to be multiplexed is not limited to information transmitted on the PBCH. Furthermore, the reference signal is not limited to a signal used for decoding the system information.

[0248] The base station 20 performs resource mapping of the system information (PBCH) and the reference signal (DMRS) to the time or logical resource (time resource or logical resource) (corresponding to the first resource mapping). Then, the base station 20 applies DFT processing (e.g., transform precoding) to the mapped system information and reference signal collectively to generate a DFT signal including the system information and the reference signal.

[0249] The base station 20 maps this DFT signal (PBCH / DMRS) to the frequency and time resources (corresponding to the second resource mapping). The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (OFDM baseband signal) including the system information (PBCH) and the reference signal (DMRS).

[0250] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0251] Moreover, in the example mentioned above, the base station 20 multiplexes two pieces of system information (e.g., two PBCHs), the number of multiplexed pieces of system information is not limited to two. The base station 20 can multiplex one piece of system information and a reference signal, or it can multiplex three or more pieces of system information with a reference signal.

[0252] Further, in the example mentioned above, the number of reference signals multiplexed by the base station 20 is set to three (e.g., three DMRSs), but the number of reference signals to be multiplexed is not limited to three. The base station 20 can multiplex two or less reference signals and system information, or it can multiplex four or more reference signals and system information.

[0253] As described above, the base station 20 is capable of reducing PAPR by collectively (multiplexing) applying DFT processing to the system information and the reference signal.

[0254] (Synchronization Signal, System Information, and Reference Signal) Fig. 24 is a diagram illustrating an example of multiplexing a synchronization signal, system information, and reference signal according to an embodiment of the present disclosure. Fig. 24 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to a time or logical resource up to when it executes IFFT processing.

[0255] In this description, an example is illustrated in which PSS and SSS are multiplexed as a synchronization signal, but the synchronization signal to be multiplexed is not limited to PSS and SSS. For example, the synchronization signal can be consecutively arranged synchronization signal to which a modulation scheme capable of reducing PAPR (e.g., low-order modulation) is applied.

[0256] In addition, in this description, an example is illustrated in which information transmitted on PBCH is multiplexed as system information. Moreover, the system information to be multiplexed is not limited to information transmitted on the PBCH.

[0257] Further, in this description, an example is illustrated in which a signal used for decoding system information (e.g., DMRS) is multiplexed as a reference signal. Moreover, the reference signal is not limited to a signal used for decoding the system information.

[0258] The base station 20 performs resource mapping (corresponding to the first resource mapping) to map a plurality of synchronization signals (PSS and SSS), system information (PBCH), and a reference signal (DMRS) to a time or logical resource (time resource or logical resource).

[0259] Subsequently, the base station 20 applies DFT processing (e.g., transform precoding) collectively to the mapped multiple synchronization signals, system information, and reference signal to generate a DFT signal including the system information and the reference signal.

[0260] The base station 20 maps the DFT signal (PSS / SSS / PBCH / DMRS) to the frequency and time resources (corresponding to the second resource mapping). The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (i.e., OFDM baseband signal) including the PSS, SSS, system information (PBCH), and reference signal (DMRS).

[0261] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0262] Moreover, in this description, the number of synchronization signals multiplexed by the base station 20 is two (e.g., PSS and SSS), but the number of synchronization signals to be multiplexed is not limited to two. The base station 20 can multiplex one synchronization signal with system information and / or a reference signal, or can multiplex three or more synchronization signals with the system information and / or reference signal.

[0263] Further, in this description, the number of pieces of system information multiplexed by the base station 20 is two (e.g., two PBCHs), but the number of pieces of system information to be multiplexed is not limited to two. The base station 20 can multiplex one piece of system information with a synchronization signal and / or a reference signal, or can multiplex three or more system information items with the synchronization signal and / or reference signal.

[0264] Further, in the example mentioned above, the number of reference signals multiplexed by the base station 20 is set to three (e.g., three DMRSs), but the number of reference signals to be multiplexed is not limited to three. The base station 20 can multiplex two or less reference signals with a synchronization signal and / or system information, or it can multiplex four or more reference signals with the synchronization signal and / or system information.

[0265] As described above, the base station 20 is capable of reducing the number of times that DFT processing is applied while reducing PAPR by collectively (multiplexing) the synchronization signal, system information, and reference signal and applying DFT processing.

[0266] (Signal Division) Figs. 25 and 26 are diagrams illustrating other examples of multiplexing a synchronization signal and system information according to an embodiment of the present disclosure. Fig. 25 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to a time or logical resource up to when it performs DFT processing. Fig. 26 illustrates the processing from when the base station 20 performs the second resource mapping after completing the DFT processing and maps the signal to a time or logical resource up to when it performs IFFT processing.

[0267] As illustrated in Fig. 25, the base station 20 divides the signal that has undergone the first resource mapping. In this example, the base station 20 divides the PSS, SSS, and PBCH signals into two (first and second divided signals) at the SSS.

[0268] Thus, the first divided signal includes the PSS and a portion of the SSS. Additionally, the second divided signal includes another portion of the SSS and the PBCH.

[0269] The base station 20 performs DFT processing on the first divided signal to generate a first DFT signal. Additionally, the base station 20 performs DFT processing on the second divided signal to generate a second DFT signal.

[0270] Next, the base station 20 maps the first DFT signal (PSS / SSS) and the second DFT signal (PSS / PBCH) to the frequency and time resources (corresponding to the second resource mapping). In this case, the base station 20 maps the first and second DFT signals in the order of the first DFT signal and the second DFT signal on the time axis.

[0271] The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped first and second DFT signals to generate an IFFT signal (i.e., an OFDM baseband signal) including the PSS, SSS, and system information (PBCH).

[0272] Moreover, in this example, the case where the base station 20 divides a signal in which a synchronization signal and system information are multiplexed into two is described, but the signals to be divided by the base station 20 are not limited to such a signal. For example, the base station 20 can divide various types of signals such as a signal in which synchronization signals are multiplexed, or a signal in which system information and reference signals are multiplexed as described above. Alternatively, the base station 20 can divide a plurality of signals to which the first resource mapping described below is applied in a similar manner.

[0273] Further, the number of divisions into which the base station 20 divides the signal is not limited to two and can be three or more. In addition, the division positions of the signal are not limited to the example in Fig. 25. For example, the base station 20 can divide the signal at any position, such as dividing the signal so that the first divided signal includes the PSS and SSS, and the second divided signal includes the PBCH.

[0274] As described above, the division of multiple signals to which the first resource mapping is applied makes it possible for the base station 20 to prevent the frequency bandwidth from becoming excessively in the case of performing the second resource mapping. In other words, the base station 20 can limit the frequency bandwidth of the downlink signal.

[0275] <4-1-2. Control Signal and Reference Signal> The following describes an example in which the base station 20 multiplexes the control signal and the reference signal.

[0276] Fig. 27 is a diagram illustrating an example of multiplexing the control signal and the reference signal according to an embodiment of the present disclosure. Fig. 27 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to the time or logical resource up to when it performs the IFFT processing.

[0277] In Fig. 27, an example in which a signal transmitted via PDCCH is multiplexed as a control signal and a DMRS is multiplexed as a reference signal is illustrated. Additionally, in this description, an example is illustrated in which control signals addressed to the first to third UEs 50 are multiplexed.

[0278] Moreover, the control signal (PDCCH) and reference signal (DMRS) illustrated in this example are merely illustrative and are not limited to thereto. For example, the control signal can be addressed to two or less UEs 50 or can be addressed to four or more UEs 50.

[0279] As illustrated in Fig. 27, the base station 20 performs resource mapping of the control signal (PDCCH) and reference signal (DMRS) to the time or logical resource (corresponding to the first resource mapping).

[0280] At this event, the base station 20 can arrange the resource-mapped signals continuously on the time or logical resource. In this way, arranging the signals continuously on the time or logical resource makes it possible for the base station 20 ton prevent an increase in PAPR.

[0281] Next, the base station 20 collectively applies DFT processing (e.g., transform precoding) to the mapped control signal (PDCCH) and reference signal (DMRS) to generate a DFT signal including the control signal and the reference signal.

[0282] The base station 20 maps the DFT signal ("Transform precoded PDCCH + DMRS for 1stto 3rdUE" in Fig. 27) to frequency and time resources (corresponding to the second resource mapping).

[0283] At this event, the base station 20 can arrange the control signal and / or reference signal mapped to the time and frequency resources continuously on the frequency axis. Arranging the control signal and / or reference signal continuously on the frequency axis makes it possible for the base station 20 to prevent an increase in PAPR.

[0284] The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (OFDM baseband signal) including the control signal and the reference signal.

[0285] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0286] In this description, for example, in the first resource mapping, a control signal transmission resource set can be defined. For example, a resource area of the control signal used for each of the terminal devices 50 can be defined as the control signal resource set used in the first resource mapping.

[0287] For example, one or more resource sets can be defined for each of the terminal devices 50 as the control signal resource set used in the first resource mapping (such as, Control Resource Set for 1st resource mapping: 1st CORESET).

[0288] In this example, if DFT processing is not performed (in the case of a multi-carrier modulation scheme), the control signal resource set used in the first resource mapping is not necessarily defined for each terminal device 50. In this case, for example, a control signal resource set used in the second resource mapping (such as, Control Resource Set for 2nd resource mapping: 2nd CORESET) can be defined.

[0289] For example, one or more common resource sets common to the terminal devices 50 (Common 1st CORESET) can be defined as the control signal resource set used in the first resource mapping (such as, Control Resource Set for 1st resource mapping: CORESET for 1st).

[0290] In this example, if DFT processing is not performed (in the case of a multi-carrier modulation scheme), a control signal resource set used in the first resource mapping that is common to the terminal devices 50 is not necessarily defined. In such a case, for example, a control signal resource set common to the terminal devices 50 used in the second resource mapping (e.g., Common Control Resource Set for 2nd resource mapping: Common 2nd CORESET) can be defined.

[0291] For example, the 1st CORESET used in the first resource mapping can include one or more control signal search spaces.

[0292] The terminal devices 50 attempt to decode the control signal included in this search space. The search space can be defined as a search space specific to the terminal devices 50 (UE-Specific Search Space). Alternatively, the search space can be defined as a search space common to the terminal devices 50 (Common Search Space).

[0293] (Omission of Interleaving Processing) In this description, in the case where a single-carrier modulation scheme is applied to downlink communication, the base station 20 can perform the second resource mapping on the control signal and / or reference signal without applying interleaving.

[0294] Fig. 28 is a diagram illustrating an example of CCE-to-REG mapping with interleaving applied. For example, the base station 20 applies interleaving to a resource element group (REGs) and assigns it to a control channel element (CCEs) that constitutes the CORESET.

[0295] In this example, since the base station 20 applies interleaving, consecutive REGs are placed in different elements within the CORESET.

[0296] Fig. 29 is a diagram illustrating an example of CCE-to-REG mapping without applying interleaving. For example, the base station 20 assigns the resource element group (REG) to the control channel element (CCE) that constitutes the CORESET without applying interleaving to the resource element group (REG).

[0297] In this example, since the base station 20 does not apply interleaving, the consecutive REGs are continuously arranged within the CORESET without being rearranged.

[0298] In the present embodiment, it is assumed that the base station 20 performs downlink communication in accordance with a single-carrier modulation scheme (e.g., DFT-S-OFDM) in which the base station 20 applies DFT processing (e.g., transform precoding).

[0299] In this case, the DFT processing yields an effect equivalent to mapping the signal across the entire frequency domain. Thus, even if the base station 20 applies interleaving to the control signal and / or reference signal, it is not necessarily possible to achieve a satisfactory effect.

[0300] Thus, in the present embodiment, the base station 20 can perform the second resource mapping on the control signal and / or reference signal without applying interleaving. This allows the base station 20 to reduce the signal processing to be performed, which is expected to lead to a reduction in processing delay.

[0301] Moreover, although the example describes that the base station 20 does not apply interleaving to the control signal and / or reference signal, the signal to which interleaving is not applied are not limited to the control signal and / or reference signal. The base station 20 can also perform the second resource mapping on signals other than the control signal and / or reference signal without applying interleaving.

[0302] <4-1-3. Data Signal and Reference Signal> An example in which the base station 20 multiplexes the data signal and the reference signal is now illustrated.

[0303] Fig. 30 is a diagram illustrating an example of multiplexing the data signal and the reference signal according to an embodiment of the present disclosure. Fig. 30 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to the time or logical resource up to when it performs the IFFT processing.

[0304] In Fig. 30, an example is illustrated in which a signal transmitted via PDSCH is multiplexed as the data signal and DMRS is multiplexed as the reference signal. Additionally, in this description, an example is illustrated in which control signals addressed to the first to third UEs 50 are multiplexed.

[0305] Moreover, the data signal (PDSCH) and the reference signal (DMRS) illustrated in this example are merely examples and are not limited to thereto. For example, the data signal can be addressed to two or fewer UEs 50 or can be addressed to four or more UEs 50.

[0306] As illustrated in Fig. 30, the base station 20 performs resource mapping of the data signal (PDSCH) and reference signal (DMRS) to the time or logical resource (corresponding to the first resource mapping).

[0307] At this event, the base station 20 can arrange the resource-mapped signals continuously on the time or logical resource. In this way, arranging the signals continuously on the time or logical resource makes it possible for the base station 20 ton prevent an increase in PAPR.

[0308] Subsequently, the base station 20 applies DFT processing (e.g., transform precoding) to the mapped data signal (PDSCH) and the reference signal (DMRS) collectively to generate a DFT signal including the data signal and the reference signal.

[0309] The base station 20 maps the DFT signal ("Transform precoded PDSCH + DMRS for 1stto 3rdUE" in Fig. 30) to the frequency and time resources (corresponding to the second resource mapping).

[0310] At this event, the base station 20 can arrange the data signal and / or reference signal mapped to the time and frequency resources continuously on the frequency axis. By arranging the data signal and / or reference signal continuously on the frequency axis, it is possible for the base station 20 to prevent an increase in PAPR.

[0311] The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (an OFDM baseband signal) including the data signal and the reference signal.

[0312] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0313] Fig. 31 is a diagram illustrating another example of multiplexing a data signal and a reference signal according to an embodiment of the present disclosure. In this description, this example is the same as that illustrated in Fig. 30, except that the base station 20 multiplexes a channel state information reference signal (CSI-RS) in addition to the DMRS as the reference signal.

[0314] As described above, the reference signal to be multiplexed is not limited to DMRS and can be CSI-RS or any other reference signals.

[0315] <4-1-4. Reference Signal> An example is now illustrated in which the base station 20 multiplexes multiple different reference signals.

[0316] Fig. 32 is a diagram illustrating an example of multiplexing a reference signal according to an embodiment of the present disclosure. Fig. 32 illustrates the processing from when the base station 20 performs the first resource mapping and maps the signal to the time or logical resource up to when it executes IFFT processing.

[0317] In Fig. 32, an example is illustrated in which a reference signal#1, a reference signal#2, and a reference signal#3 are multiplexed as reference signals.

[0318] Moreover, the reference signals #1 to #3 are merely illustrative and are not limiting. For example, the number of reference signals can be two or less, or can be four or more. For example, reference signals #1 to #4 can be multiplexed.

[0319] As illustrated in Fig. 32, the base station 20 performs resource mapping of the reference signals (reference signals #1 to #3) to the time or logical resource (corresponding to the first resource mapping). At this event, the base station 20 can arrange the resource-mapped signals continuously on the time or logical resource. In this way, arranging the reference signals continuously on the time or logical resource makes it possible for the base station 20 to prevent an increase in PAPR.

[0320] Subsequently, the base station 20 applies DFT processing (e.g., transform precoding) to the mapped reference signals (reference signals #1 to #3) collectively to generate a DFT signal including the reference signals.

[0321] The base station 20 maps the DFT signal ("Transform precoded multiple Reference Signals" in Fig. 32) to the frequency and time resources (corresponding to the second resource mapping).

[0322] At this event, the base station 20 can arrange the reference signals to be mapped to the time and frequency resources continuously on the frequency axis. By arranging the reference signals continuously on the frequency axis, it is possible for the base station 20 to prevent an increase in PAPR.

[0323] The base station 20 applies IFFT processing (e.g., OFDM baseband signal generation) to the mapped DFT signal to generate an IFFT signal (an OFDM baseband signal) including the reference signal.

[0324] The base station 20 performs transmission signal processing on the IFFT signal to generate a downlink signal (wireless signal), which is then transmitted to the terminal device 50.

[0325] Examples of the reference signal include the following signals. Moreover, the following signals are merely examples, and reference signals other than those listed here can be multiplexed. -CSI-RS -DMRS -Phase Tracking Reference Signal (PT-RS) -Tracking Reference Signal (TRS) -Positioning Reference Signal (PRS) 　-CSI Interference Measurement (CSI-IM)

[0326] In this description, for example, a reference signal group resource can be defined in the first resource mapping. For example, the terminal devices 50 can use the reference signal group resource (reference signal transmission group resource) to perform processing using the reference signal, such as estimating the channel state.

[0327] The reference signal group resource can be used for transmission addressed to a single terminal device 50, or can be used for transmission addressed to a plurality of terminal devices 50.

[0328] For example, of the reference signal group resource, a resource area of the reference signal to be used for each of the terminal devices 50 can be defined.

[0329] For example, one or more resource sets can be defined for each of the terminal devices 50 as a reference signal resource set (RSRESET).

[0330] Fig. 33 is a diagram illustrating an example of a resource set according to an embodiment of the present disclosure. In Fig. 33, as RSRESET #0, resource areas from the fourth reference signal #1 from the head to the seventh reference signal #1 from the head are defined. In addition, as RSRESET #1, a resource area from the first reference signal #1 to the sixth reference signal #3 from the beginning is defined.

[0331] The reference signal group resource can be configured specifically for each of the terminal devices 50, or can be configured commonly for the terminal devices 50.

[0332] <4-2. Example of Configuration of First Resource Mapping> An example of the configuration in the case where the first resource mapping is performed is described below.

[0333] (Continuity of Multiplexed Signals) The multiple different signals multiplexed by the base station 20 can be resource-mapped continuously on time or logical resource. Alternatively, the multiple different signals multiplexed by the base station 20 can be resource-mapped discontinuously on time or logical resource.

[0334] (Maximum Number of Resources) The maximum number of resources for the first resource mapping can be calculated from the following values, among others: -Bandwidth of configured component carrier -Bandwidth of configured bandwidth part (BWP) -Size of configured discrete Fourier transform -Size of configured fast Fourier transform.

[0335] (Resource-Related Information) For each of the terminal devices 50, one or more pieces of information regarding the limitation of resources to which the first resource mapping is applied (resource-related information) can be configured.

[0336] The details of the information to be configured include at least one of the following: -Starting point of first resource mapping -Resource width of first resource mapping -Signal point bundle information obtained by bundling multiple pieces of signal point information used in first resource mapping -Interleaving information applied in first resource mapping -Information regarding transmission resource range of control information transmitted in first resource mapping.

[0337] Moreover, the information listed here is an example, and other types of information can be configured as resource-related information for each of the terminal devices 50.

[0338] The resource-related information can be configured, for example, via DCI. Alternatively, the resource-related information can be configured via MAC CE. The resource-related information can be configured via RRC signaling. The resource-related information can be defined as static information in a standard or the like.

[0339] The configuration of the resource-related information makes it possible for the terminal devices 50 to search for a received signal by limiting the resources configured based on the information. This enables the terminal devices 50 to reduce the amount of processing required to search for a received signal.

[0340] (Signaling) The base station 20 notifies the terminal devices 50 of, for example, information related to the first resource mapping (mapping information). This notification can be dynamically notified via DCI or the like.

[0341] The mapping information to be notified can include at least one of the following information or the like: -Transmission resource start position -Number of transmission resources -Transmission resource end position -Whether interleaving is applied.

[0342] The base station 20 may, for example, notify the terminal devices 50 of information related to the method of transmitting the reference signal (reference information). For example, the reference information can include information indicating whether the transmitted reference signal is a reference signal specific to one of the terminal devices 50 or a reference signal common to the terminal devices 50.

[0343] (Processing Order) In the above-mentioned signal processing, the base station 20 performs the first resource mapping and then performs the DFT processing. The order of the processing performed by the base station 20 is not limited to the exemplary processing order described above.

[0344] For example, the base station 20 can perform the first resource mapping immediately before the DFT processing or can perform the first resource mapping earlier than immediately before the DFT processing.

[0345] For example, the base station 20 can perform the first resource mapping before (e.g., immediately before) antenna port mapping. Alternatively, for example, the base station 20 can perform the first resource mapping before (e.g., immediately before) layer mapping.

[0346] For example, the base station 20 can perform the first resource mapping before (e.g., immediately before) modulation. Alternatively, for example, the base station 20 can perform the first resource mapping before (e.g., immediately before) scrambling.

[0347] (Others) For example, the base station 20 can perform downlink communication by applying signal multiplexing using the first resource mapping in a cell to which BWP is not applied and can perform downlink communication without applying the first resource mapping in a cell to which BWP is applied.

[0348] For example, in the case where the configured frequency bandwidth is the same as the component carrier (CC), the base station 20 can perform downlink communication by applying signal multiplexing using the first resource mapping. In the case where the configured frequency bandwidth is not the same as that of the component carrier (CC), i.e., different, the base station 20 can perform downlink communication without applying the first resource mapping.

[0349] For example, the base station 20 can perform downlink communication by applying signal multiplexing using the first resource mapping in a secondary cell (SCell). The base station 20 can perform downlink communication without applying the first resource mapping in a cell other than the SCell, for example, a primary cell (PCell).

[0350] For example, the base station 20 can perform downlink communication by applying signal multiplexing using the first resource mapping in an SCG PSCell of a secondary cell group (SCG). The base station 20 can perform downlink communication without applying the first resource mapping in a cell other than the SCG PSCell.

[0351] For example, the base station 20 can perform downlink communication by applying signal multiplexing using the first resource mapping in an SCG SCell of a Secondary Cell Group (SCG). The base station 20 can perform downlink communication without applying the first resource mapping in a cell other than the SCG SCell.

[0352] In the case of performing downlink communication to which the first resource mapping is applied, the base station 20 can set the DFT size used in the DFT processing (e.g., transform precoding) performed after the first resource mapping to be the same as the IFFT size. The IFFT size refers to the size used in the IFFT processing performed after the DFT processing.

[0353] <<5. Example of Signal Reception Processing>> An example of downlink signal reception processing by one of the terminal devices 50 according to the present embodiment is now described.

[0354] <5-1. Synchronization Signal and / or System Information> Figs. 34 and 35 are diagrams illustrating an example of the downlink signal reception processing according to an embodiment of the present disclosure. Fig. 34 illustrates the processing up to when the base station 20 performs IDFT processing on the received signal. Fig. 35 illustrates the processing up to when the base station 20 performs the first resource de-mapping and obtains respective signals.

[0355] In this example, the terminal device 50 receives a downlink signal multiplexed with a plurality of synchronization signals (e.g., PSS and SSS), system information (e.g., information transmitted on PBCH), and reference information (e.g., DMRS).

[0356] The terminal device 50 performs FFT processing (e.g., OFDM baseband signal generation) on the received signal to generate an FFT signal (an OFDM baseband signal), which is a signal on the frequency and time axes.

[0357] The terminal device 50 performs demapping to extract a signal of a resource (IDFT resource) to be subjected to IDFT processing (hereinafter also referred to as an IDFT target signal) from the FFT signal, based on information regarding the second resource mapping that is either pre-notified or implicitly determined (this demapping corresponds to the second resource de-mapping).

[0358] The terminal device 50 performs IDFT processing (transform precoding) on the IDFT target signal to obtain an IDFT signal. The terminal device 50 can perform IFFT processing instead of IDFT processing.

[0359] The terminal device 50 performs demapping to extract a synchronization signal (PSS / SSS) and system information (PBCH including DMRS) from the IDFT signal (first resource de-mapping). At this event, the terminal device 50 can extract a resource from which a signal is to be extracted based on information regarding the first resource mapping that is pre-notified or statically determined.

[0360] The terminal device 50 performs processing corresponding to the extracted signal. For example, the terminal device 50 correlates the received PSS with a candidate PSS signal sequence (potential PSS sequence) to determine the PSS. Similarly, for example, the terminal device 50 correlates the received SSS with a candidate SSS signal sequence (potential SSS sequence) to determine the SSS.

[0361] The terminal device 50 performs channel estimation using a reference signal (in this example, DMRS) included in the PBCH. The terminal device 50 performs, based on the channel estimation result, subsequent decoding processing (e.g., de-mapper) and the like, and decodes the system information or the like transmitted in the PBCH.

[0362] Moreover, in this description, although the terminal device 50 is described as receiving the PSS and / or SSS as the synchronization signal, the synchronization signal received by the terminal device 50 is not limited to the PSS and / or SSS. For example, the synchronization signal can be consecutively arranged synchronization signal to which a modulation scheme capable of reducing PAPR (e.g., low-order modulation) is applied.

[0363] Further, in this description, the system information is described as information transmitted on the PBCH, but the system information is not limited to the information transmitted on the PBCH. Additionally, in this description, the reference signal is described as a signal used to decode the system information (e.g., DMRS), but the reference signal is not limited to the signal used to decode the system information.

[0364] Further, the received signal can include at least one of a synchronization signal, system information, and a reference signal. For example, the terminal device 50 performs processing similar to that illustrated in Figs. 34 and 35 even in the case where the received signal includes the system information and the reference information.

[0365] <5-2. Control Signal and Reference Signal> Fig. 36 is a diagram illustrating another example of the reception processing of the downlink signal according to the embodiment of the present disclosure. Moreover, the processing up to the base station 20 executing IDFT processing on the received signal is the same as the processing illustrated in Fig. 34, and thus the description here is omitted. Fig. 36 illustrates the processing up to the base station 20 performing the first resource de-mapping and obtaining each signal.

[0366] In this description, the terminal device 50 receives a downlink signal in which a control signal (e.g., a signal transmitted on the PDCCH) and reference information (e.g., DMRS) are multiplexed.

[0367] The terminal device 50 performs demapping to extract a control signal or the like addressed to itself (PDCCH / DMRS) from the IDFT signal (first resource de-mapping). At this event, the terminal device 50 can extract a resource from which a signal is to be extracted based on information regarding the first resource mapping that is pre-notified or statically determined.

[0368] The terminal device 50 performs signal processing on the control signal or the like intended to the terminal device. For example, the first terminal device 501performs signal processing on the PDCCH addressed to the first terminal device 501(PDCCH for 1stUE) extracted by the first resource mapping.

[0369] At this event, the first terminal device 501can perform channel estimation using the DMRS transmitted using the resource of the first terminal device 501.

[0370] Alternatively, the first terminal device 501can perform channel estimation using the DMRS included in the received signal (e.g., IDFT signal). In other words, the first terminal device 501can perform channel estimation using the DMRS transmitted using the resource of the first to third terminal devices 501to 503.

[0371] The channel estimation implemented using the DMRS included in the received signal (e.g., IDFT signal) makes it possible for the first terminal device 501to further improve the channel estimation accuracy.

[0372] The first terminal device 501performs subsequent decoding processing (e.g., de-mapper) based on the channel estimation result, and decodes the control signal transmitted via the PDCCH.

[0373] The second and third terminal devices 502and 503similarly decode the control information or the like transmitted via the PDCCH that is intended for each individual terminal device 502and 503.

[0374] <5-3. Data Signal and Reference Signal> Fig. 37 is a diagram illustrating another example of the reception processing of the downlink signal according to the embodiment of the present disclosure. Moreover, the processing up to the base station 20 executing IDFT processing on the received signal is the same as the processing illustrated in Fig. 34, and thus the description here is omitted. Fig. 37 illustrates the processing up to the point where the base station 20 performs the first resource de-mapping and obtains each signal.

[0375] In this example, the terminal device 50 receives a downlink signal multiplexed with a data signal (e.g., a signal transmitted via the PDSCH) and reference information (e.g., DMRS).

[0376] The terminal device 50 performs demapping to extract the control signal or the like (PDSCH / DMRS) addressed to itself from the IDFT signal (first resource de-mapping). At this event, the terminal device 50 can extract a resource from which a signal is to be extracted based on information regarding the first resource mapping that is pre-notified or statically determined.

[0377] The terminal device 50 performs signal processing on the control signal or the like intended to the terminal device. For example, the first terminal device 501performs signal processing on the PDCCH (PDSCH for 1stUE) addressed to the first terminal device 501that is extracted by the first resource mapping.

[0378] At this event, the first terminal device 501can perform channel estimation using the DMRS transmitted using the resource of the first terminal device 501.

[0379] Alternatively, the first terminal device 501can perform channel estimation using the DMRS included in the received signal (e.g., IDFT signal). In other words, the first terminal device 501can perform channel estimation using the DMRS transmitted using the resource of the first to third terminal devices 501to 503.

[0380] The channel estimation implemented using the DMRS included in the received signal (e.g., IDFT signal) makes it possible for the first terminal device 501to further improve the channel estimation accuracy.

[0381] The first terminal device 501performs subsequent decoding processing (e.g., a de-mapper) based on the channel estimation result, and decodes the data signal transmitted via the PDSCH.

[0382] The second and third terminal devices 502and 503similarly decode the control information or the like transmitted via the PDCCH that is intended for each individual terminal device 502and 503.

[0383] Moreover, in this example, although the DMRS is included as the reference signal, in addition to or instead of the DMRS, a CSI-RS can also be included as the reference signal.

[0384] <5-4. Reference Signal> Fig. 38 is a diagram illustrating another example of the downlink signal reception processing according to the embodiment of the present disclosure. Moreover, the processing up to the base station 20 executing IDFT processing on the received signal is the same as the processing illustrated in Fig. 34, and thus the description here is omitted. Fig. 38 illustrates the processing performed by the base station 20 up to the point of performing the first resource de-mapping and obtaining each signal.

[0385] In this example, the terminal device 50 receives a downlink signal in which multiple different reference signals are multiplexed.

[0386] The terminal device 50 performs demapping to extract a reference signal addressed to itself from the IDFT signal (first resource de-mapping). At this event, the terminal device 50 can extract a resource from which a signal is to be extracted based on information regarding the first resource mapping that is pre-notified or statically determined.

[0387] The terminal device 50 performs subsequent signal processing on the reference signal addressed to itself. For example, the first terminal device 501performs subsequent signal processing on the reference signal (e.g., reference signal #1) extracted by the first resource mapping and addressed to the first terminal device 501.

[0388] The second and third terminal devices 502and 503similarly extract reference signals #2 and #3 addressed to themselves and perform subsequent signal processing.

[0389] <<6. Relationship between Signal Waveforms>> 　For example, the downlink signal waveform and the uplink signal waveform can have the following relationship.

[0390] For example, in the case where a second signal waveform (a single-carrier modulation scheme) is configured for downlink communication, the second signal waveform is also configured for uplink communication.

[0391] In this case, the terminal device 50 assumes that the second signal waveform configured for downlink communication is also configured for uplink communication. In other words, in the case where the second signal waveform is configured for downlink communication, the terminal device 50 assumes that the first signal waveform (multicarrier modulation scheme) is not configured for uplink communication.

[0392] For example, in the case of considering coverage at a cell edge or the like, it is assumed that the first signal waveform is configured for both the uplink and downlink communication.

[0393] For example, in the case where the first signal waveform is configured for downlink communication, the first signal waveform is also configured for uplink communication.

[0394] In this case, the terminal device 50 assumes that the first signal waveform configured for downlink communication is also configured for uplink communication. In other words, in the case where the first signal waveform is configured for downlink communication, the terminal device 50 assumes that the second signal waveform is not configured for uplink communication.

[0395] In this way, for example, in a coverage where communication using the first signal waveform is possible in downlink communication, it is assumed that communication using the first signal waveform is also performed in uplink communication.

[0396] Alternatively, in the case where the first signal waveform is configured for downlink communication, either or both of the first and second signal waveforms can be configured for uplink communication.

[0397] In this case, the terminal device 50 assumes that, in the case where the first signal waveform is configured for the downlink communication, the first signal waveform and / or the second signal waveform is configured for the uplink communication.

[0398] For example, in the case where the second signal waveform is configured for uplink communication, the second signal waveform is also configured for downlink communication.

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

[0400] For example, in the case of considering coverage at a cell edge or the like, it is assumed that the first signal waveform is configured for both the uplink and downlink communication.

[0401] For example, in the case where the first signal waveform is configured for uplink communication, the first signal waveform is also configured for downlink communication.

[0402] In this case, the terminal device 50 assumes that the first signal waveform configured for uplink communication is also configured for downlink communication. In other words, in the case where the first signal waveform is configured for uplink communication, the terminal device 50 assumes that the second signal waveform is not configured for downlink communication.

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

[0404] Alternatively, in the case where the first signal waveform is configured for uplink communication, the first signal waveform and / or the second signal waveform is configured for downlink communication.

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

[0406] <<7. Example of Signal Waveform>> 　In the embodiment described above, 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.

[0407] For example, the first signal waveform can be any signal waveform based on a multicarrier modulation scheme. Examples of multicarrier modulation schemes include the followings: -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).

[0408] For example, the second signal waveform can be any signal waveform based on a single-carrier modulation scheme. Examples of single-carrier modulation schemes include the followings: -Constant envelope -SC-QAM (Single Carrier - Quadrature Amplitude Modulation) -SC-FDE (single-carrier modulation with frequency domain equalization) -SC-FDM (Single Carrier - Frequency Division Multiple) -Zero-tail SC-FDM.

[0409] <<8. Other Embodiments>> The processing according to the embodiment described above can be implemented in various different forms other than those specifically described.

[0410] In a dual connectivity environment, the terminal devices 50 connect to and communicate with a plurality of base stations 20. At this event, the downlink signal waveform can be configured for each of the plurality of base stations 20 to which it is connected.

[0411] For example, it is assumed that the terminal devices 50 are connected to base stations 20A and 20B using dual connectivity. In this case, the terminal devices 50 can use the second signal waveform for downlink communication with the base station 20A, and the first signal waveform for downlink communication with the base station 20B.

[0412] Alternatively, the terminal devices 50 can use the first signal waveform for downlink communication with both the base station 20A and the base station 20B. The terminal devices 50 can use the second signal waveform for downlink communication with both the base station 20A and the base station 20B.

[0413] In the dual connectivity environment, the terminal devices 50 can acquire information (e.g., corresponding to the above-mentioned second waveform information) regarding the signal waveform used for downlink communication by the other base station 20 (e.g., base station 20B) from one base station 20 (e.g., base station 20A).

[0414] For example, the terminal devices 50 receive a downlink signal from the other base station 20 based on the acquired second waveform information.

[0415] In addition, for example, in the case where the terminal devices 50 communicate with one base station 20 using both the first signal waveform and the second signal waveform, the communication using one of the signal waveforms can be switched from one base station 20 to another base station 20.

[0416] For example, it is assumed that the terminal devices 50 communicate with the base station 20A using both the first signal waveform and the second signal waveform. In this case, the terminal devices 50 can 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.

[0417] For example, in the case where the quality of the downlink communication using the first signal waveform with the base station 20A falls below a threshold, the base station 20A (or the terminal device 50) determines to switch the downlink communication using the first signal waveform from the base station 20A to the base station 20B.

[0418] Alternatively, for example, in the case where the quality of the downlink communication using the first signal waveform with the base station 20B becomes equal to or higher than a threshold, the base station 20A (or the terminal device 50) determines to switch the downlink communication using the first signal waveform from the base station 20A to the base station 20B.

[0419] For example, in the case where the quality of the downlink communication using the first signal waveform with the base station 20A becomes lower than the quality of the downlink communication using the first signal with the base station 20B by an offset or more, the base station 20A (or the terminal device 50) determines to switch from the base station 20A to the base station 20B.

[0420] For example, the control device that controls the base station 20 and the terminal devices 50 in each of the above-mentioned embodiments can be implemented using a dedicated computer system or a general-purpose computer system.

[0421] For example, a communication program for executing the above-mentioned operations is stored in a computer-readable recording medium such as an optical disk, semiconductor memory, magnetic tape, or flexible disk, and distributed. Then, for example, by installing the program in a computer and executing the above-described processing, the control device is implemented. In this case, the control device can be an external device (e.g., a personal computer) of the base station 20 or the terminal device 50. Additionally, the control device can also be an internal device (e.g., the control unit 103 or 203) of the base station 20 or the terminal device 50.

[0422] Further, the communication program described above can be stored on a disk device provided in a server device on a network such as the Internet so that it can be downloaded to a computer. In addition, the above-mentioned functions can also be implemented through cooperation between an operating system (OS) and application software. In this case, the portion other than the OS can be distributed by being stored in a medium, or the portion other than the OS can be stored in a server device and made available for download to a computer.

[0423] Further, among the processing described in the above-described embodiment, all or part of the processing described as being performed automatically can be performed manually, or all or part of the processing described as being performed manually can be performed automatically using a known method. Furthermore, unless otherwise specified, the information including the processing procedures, specific names, various types of data or parameters presented in the above documents and drawings can be changed as desired. For example, the various types of information illustrated in each figure are not limited to the illustrated information.

[0424] Further, the individual components of the illustrated devices are conceptual representations of their functions and are not necessarily physically configured as illustrated. In other words, the specific form of distribution or integration of each device is not limited to the illustrated examples, and all or part of the devices can be configured to be functionally or physically distributed or integrated in any unit depending on various factors such as load or usage conditions.

[0425] In addition, the above-mentioned embodiments can be appropriately combined within the scope of not causing contradictions in the processing contents.

[0426] Furthermore, the effects described herein are merely illustrative and are not limiting, and other effects can be achieved.

[0427] Additionally, for example, the embodiments can be implemented as any configuration constituting a device or system, such as a processor as a system large scale integration (LSI), a module using a plurality of processors, a unit using a plurality of modules, a set or the like in which an additional function is added to a unit (i.e., a partial configuration of a device).

[0428] Moreover, in the embodiments, the term "system" refers to a collection of a plurality of components (such as, devices or modules (parts)), and it does not matter whether all the components are housed within the same enclosure. Thus, a plurality of devices housed in separate housings and connected via a network, and a single device in which a plurality of modules is housed in a single housing, are both systems.

[0429] Further, for example, each embodiment can have a cloud computing configuration in which one function is shared and processed jointly by a plurality of devices via a network.

[0430] <<9. Modifications and Variations>> As described above, the various embodiments of the present disclosure are described, but the technical scope of the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present disclosure. Furthermore, the components spanning different embodiments and modifications can be appropriately combined.

[0431] Furthermore, the effects of each embodiment described herein are merely illustrative and not limiting, and other effects also can be achieved.

[0432] Moreover, the present technology can also have the following configuration. (1) A base station that: applies a first resource mapping to a plurality of signals to map the plurality of signals to a time resource or a logical resource; performs a Fourier transform on the plurality of signals to which the first resource mapping is applied to generate a first transformed signal; applies a second resource mapping to the first transformed signal to map the first transformed signal to a frequency resource and the time resource; performs an inverse Fourier transform on the first transformed signal to which the second resource mapping is applied to generate a second transformed signal; and generates a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal. (2) The base station according to (1), wherein the plurality of signals includes a plurality of synchronization signals. (3) 　The base station according to (1) or (2), in which the plurality of signals includes a synchronization signal arranged contiguously. 　(4) 　The base station according to any one of (1) to (3), in which the plurality of signals includes a PSS and an SSS. 　(5) 　The base station according to any one of (1) to (4), wherein the plurality of signals includes system information and a reference signal used for decoding the system information. 　(6) 　The base station according to any one of (1) to (5), in which the plurality of signals includes a DMRS and a PBCH signal. 　(7) 　The base station according to (1), wherein the plurality of signals includes a plurality of reference signals. 　(8) 　The base station according to (7), in which the plurality of reference signals includes the reference signal addressed to a plurality of different terminal devices. 　(9) 　The base station according to (7) or (8), wherein the plurality of signals includes one or more data signals. 　(10) 　The base station according to (1), wherein the plurality of signals corresponds to signals of a plurality of different physical channels. 　(11) 　The base station according to (1), wherein the plurality of signals corresponds to a signal of a single physical channel. 　(12) 　The base station according to any one of (1) to (11), wherein the first resource mapping is applied to the plurality of signals using one or more resource sets defined for each terminal device. 　(13) 　The base station according to (12), in which one or more of the resource sets include one or more search spaces. 　(14) 　The base station according to any one of (1) to (11), wherein the first resource mapping is applied to the plurality of signals using one or more resource sets defined in common for a plurality of terminal devices. 　(15) The base station according to (14), in which the one or more resource sets include one or more search spaces. 　(16) 　The base station according to any one of (1) to (15), wherein the second resource mapping is applied to the first transformed signal without applying interleaving to the first transformed signal. 　(17) 　The base station according to any one of (1) to (16), which 　divides the multiple signals to which the first resource mapping is applied into a plurality of divided signals, 　performs the Fourier transform on each of the plurality of divided signals to generate a plurality of first transformed signals, 　applies the second resource mapping to the plurality of first transformed signals to map the plurality of first transformed signals to a frequency resource and a time resource, and 　performs the inverse Fourier transform on the plurality of first transformed signals to which the second resource mapping is applied to generate the second transformed signal. 　(18) 　The base station according to any one of (1) to (17), wherein the plurality of signals is mapped continuously on the time resource or the logical resource. 　(19) 　The base station according to any one of (1) to (18), wherein the first resource mapping is applied to the plurality of signals in accordance with a maximum number of resources calculated based on at least one of a bandwidth of a configured component carrier, a bandwidth of a configured BWP, and a size configured for the Fourier transform. 　(20) 　The base station according to any one of (1) to (19), wherein the first resource mapping is started from a configured position of the time resource or the logical resource. 　(21) 　The base station according to any one of (1) to (20), wherein the first resource mapping is applied within a configured resource width of the time resource or the logical resource. 　(22) 　The base station according to any one of (1) to (21), wherein mapping information regarding the first resource mapping is notified to a terminal device. 　(23) The base station according to (22), in which the mapping information includes information regarding any one of the start position of a transmission resource, the number of transmission resources, the end position of a transmission resource, and whether interleaving is applied to the first transformed signal. 　(24) 　The base station according to any one of (1) to (23), wherein the downlink signal is generated in a cell to which BWP is not applied. 　(25) 　The base station according to any one of (1) to (24), wherein the downlink signal is generated in a case where a configured frequency bandwidth is identical to a component carrier. 　(26) 　A terminal device that: 　receives a downlink signal to which a single-carrier modulation scheme is applied; 　applies a Fourier transform to the downlink signal to generate a second transformed signal; 　applies a second resource de-mapping to the second transformed signal to demap the second transformed signal to a frequency resource and a time resource; 　performs an inverse Fourier transform on the second transformed signal to which the second resource de-mapping is applied to generate a first transformed signal; 　applies a first resource de-mapping to the first transformed signal to demap the first transformed signal to the time resource or a logical resource; and 　generates a plurality of signals from the first transformed signal to which the first resource de-mapping is applied. 　(27) 　A terminal device that 　receives a downlink signal from a base station, 　in which the base station is configured to: 　apply a first resource mapping to a plurality of signals to map the plurality of signals to a time resource or a logical resource, 　perform a Fourier transform on the plurality of signals to which the first resource mapping is applied to generate a first transformed signal, 　apply a second resource mapping to the first transformed signal to map the first transformed signal to a frequency resource and the time resource, 　perform an inverse Fourier transform on the first transformed signal to which the second resource mapping is applied to generate a second transformed signal, and 　generate the downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal. 　(28) 　A communication method comprising: 　applying a first resource mapping to a plurality of signals to map the plurality of signals to a time resource or a logical resource; 　performing a Fourier transform on the plurality of signals to which the first resource mapping is applied to generate a first transformed signal; 　applying a second resource mapping to the first transformed signal to map the first transformed signal to a frequency resource and the time resource; 　performing an inverse Fourier transform on the first transformed signal to which the second resource mapping is applied to generate a second transformed signal; and 　generating a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal. 　(29) 　A communication method comprising: 　applying a Fourier transform to a downlink signal to which a single-carrier modulation scheme is applied to generate a second transformed signal; 　applying a second resource de-mapping to the second transformed signal to demap the second transformed signal to a frequency resource and a time resource; 　performing an inverse Fourier transform on the second transformed signal to which the second resource de-mapping is applied to generate a first transformed signal; 　applying a first resource de-mapping to the first transformed signal to demap the first transformed signal to the time resource or a logical resource; and 　generating a plurality of signals from the first transformed signal to which the first resource de-mapping is applied. 　(30) 　A communication method including 　receiving a downlink signal from a base station, 　in which the base station 　applies a first resource de-mapping to a plurality of signals to demap the plurality of signals to a time resource or logical resource, 　applying a Fourier transform to the plurality of signals to which the first resource de-mapping is applied to generate a first transformed signal, 　performing a second resource de-mapping on the first transformed signal to demap the first transformed signal to frequency resource and the time resource, 　applying an inverse Fourier transform to the first transformed signal to which the second resource de-mapping is applied to generate a second transformed signal, and 　generating the downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal.

[0433] 20 Base station 50 Terminal device 101, 201 Higher-layer processing unit 103, 203 Control unit 105, 205 Reception unit 107, 207 Transmission unit 109, 209 Transmission and reception antenna

Claims

1. A base station system, comprising: 　one or more processing circuitry configured to: 　　apply a first resource mapping to a plurality of signals to map the plurality of signals to a first physical resource or a logical resource and generate a first mapped signal; 　　perform a Fourier transform on the first mapped signal to generate a first transformed signal; 　　apply a second resource mapping to the first transformed signal to map the first transformed signal to a second physical resource and generate a second mapped signal; 　　perform an inverse Fourier transform on the second mapped signal to generate a second transformed signal; and 　　generate a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal.

2. The base station system according to claim 1, wherein the plurality of signals includes a plurality of synchronization signals.

3. The base station system according to claim 1, wherein the plurality of signals includes system information and a reference signal usable for decoding the system information.

4. The base station system according to claim 1, wherein the plurality of signals includes a plurality of reference signals.

5. The base station system according to claim 4, wherein the plurality of signals includes one or more data signals.

6. The base station system according to claim 1, wherein signals of the plurality of signals correspond to signals of a plurality of different physical channels.

7. The base station system according to claim 1, wherein signals of the plurality of signals correspond to a signal of a single physical channel.

8. The base station system according to claim 1, wherein the first resource mapping is applied to the plurality of signals using one or more resource sets defined for each of one or more terminal device.

9. The base station system according to claim 1, wherein the first resource mapping is applied to the plurality of signals using one or more resource sets defined in common for a plurality of terminal devices.

10. The base station system according to claim 1, wherein the second resource mapping is applied to the first transformed signal without applying interleaving to the first transformed signal.

11. The base station system according to claim 1, wherein the plurality of signals is mapped continuously on the first physical resource or the logical resource.

12. The base station system according to claim 1, wherein the first resource mapping is applied to the plurality of signals in accordance with a maximum number of resources calculated based on at least one of a bandwidth of a configured component carrier, a bandwidth of a configured BWP, or a size configured for the Fourier transform.

13. The base station system according to claim 1, wherein the first resource mapping is started from a configured position of the first physical resource or the logical resource.

14. The base station system according to claim 1, wherein the first resource mapping is applied within a configured resource width of the first physical resource or the logical resource.

15. The base station system according to claim 1, wherein mapping information regarding the first resource mapping is notified to a terminal device.

16. The base station system according to claim 1, wherein the downlink signal is generated in a cell to which a bandwidth part is not applied.

17. The base station system according to claim 1, wherein the downlink signal is generated in a case where a configured frequency bandwidth is identical to a component carrier.

18. A terminal device , comprising: one or more processing circuitry configured to: 　　receive a downlink signal to which a single-carrier modulation scheme is applied; 　　apply a Fourier transform to the downlink signal to generate a second transformed signal; 　　apply a second resource de-mapping to the second transformed signal to demap the second transformed signal to a second physical resource and generate a second de-mapped signal; 　　perform an inverse Fourier transform on the second de-mapped signal to generate a first transformed signal; 　　apply a first resource de-mapping to the first transformed signal to demap the first transformed signal to a first physical resource or a logical resource and generate a first de-mapped signal; and 　　generate a plurality of signals from the first de-mapped signal.

19. A communication method comprising: 　applying a first resource mapping to a plurality of signals to map the plurality of signals to a first physical resource or a logical resource and generate a first mapped signal; 　performing a Fourier transform on the first mapped signal to generate a first transformed signal; 　applying a second resource mapping to the first transformed signal to map the first transformed signal to a second physical resource and generate a second mapped signal; 　performing an inverse Fourier transform on the second mapped signal to generate a second transformed signal; and 　generating a downlink signal to which a single-carrier modulation scheme is applied from the second transformed signal.

20. A communication method comprising: 　applying a Fourier transform to a downlink signal to which a single-carrier modulation scheme is applied to generate a second transformed signal; 　applying a second resource de-mapping to the second transformed signal to demap the second transformed signal to a second physical resource and generate a second de-mapped signal; 　performing an inverse Fourier transform on the second de-mapped signal to generate a first transformed signal; 　applying a first resource de-mapping to the first transformed signal to demap the first transformed signal to a first physical resource or a logical resource and generate a first de-mapped signal; and 　generating a plurality of signals from the first de-mapped signal.

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