Communication device and communication method

Abstract

According to the present invention, a base station is provided with: a control circuit that, through non-orthogonal multiplexing, allocates a first transmission power to a first signal corresponding to a first terminal type and allocates a second transmission power to a second signal corresponding to a second terminal type; and a transmission circuit that transmits the first signal and second signal having been non-orthogonally multiplexed.

Description

[Technical Field]

[0001] The present disclosure relates to a communication device and a communication method. [Background technology]

[0002] In the standardization of 5G, new radio access technology (NR) has been specified by 3GPP, and the NR Release 15 (Rel. 15) specification has been published. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP, TR38.811 V15.2.0, “Study on New Radio (NR) to support non terrestrial networks (Release 15),” 2019-09 Summary of the Invention

[0004] However, there is room for further study on methods for improving the transmission efficiency of wireless communication in wireless communication systems.

[0005] Non-limiting embodiments of the present disclosure contribute to providing a communication device and a communication method that can improve transmission efficiency of wireless communication.

[0006] A communication device according to one embodiment of the present disclosure includes a control circuit that, in non-orthogonal multiplexing, allocates a first transmission power to a first signal corresponding to a first terminal type and allocates a second transmission power to a second signal corresponding to a second terminal type, and a transmission circuit that transmits the non-orthogonally multiplexed first signal and second signal.

[0007] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to an embodiment of the present disclosure, it is possible to improve the transmission efficiency of wireless communication.

[0009] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0010] [Figure 1] Diagram of an example architecture of a 3GPP NR system [Figure 2] Schematic diagram showing the functional separation between NG-RAN (Next Generation - Radio Access Network) and 5GC (5th Generation Core) [Figure 3] Sequence diagram of RRC (Radio Resource Control) connection setup / reconfiguration procedure [Figure 4] Schematic diagram showing usage scenarios for enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC). [Figure 5] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario [Figure 6] FIG. 1 is a block diagram showing a partial configuration of a base station according to a first embodiment; [Figure 7] FIG. 1 is a block diagram showing a partial configuration of a terminal according to a first embodiment; [Figure 8] FIG. 1 is a block diagram showing an example of a configuration of a base station according to a first embodiment; [Figure 9] FIG. 1 is a block diagram showing an example of a configuration of a terminal according to a first embodiment; [Figure 10] FIG. 1 is a block diagram showing an example of a configuration of a terminal according to a first embodiment; [Figure 11] FIG. 1 is a sequence diagram illustrating an example of an operation of downlink communication according to the first embodiment. [Figure 12] FIG. 1 is a diagram showing an example of NOMA multiplexing in downlink communication according to the first embodiment; [Figure 13] FIG. 1 is a sequence diagram illustrating an example of an operation of uplink communication according to the first embodiment. [Figure 14] FIG. 1 is a diagram showing an example of NOMA multiplexing in uplink communication according to the first embodiment; [Figure 15] FIG. 10 is a diagram showing an example of NOMA multiplexing in downlink communication according to a second embodiment. [Figure 16] FIG. 10 is a diagram showing an example of encoding and modulation of data for Internet of Things (IoT) according to a second embodiment. [Figure 17] FIG. 10 is a diagram showing an example of NOMA multiplexing in uplink communication according to a second embodiment. [Figure 18] A diagram showing an example of communication timing for IoT data and aircraft data DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0012] <5G NR system architecture and protocol stack> 3GPP is working on the next release of fifth-generation cellular technology (also known as 5G), which includes the development of New Radio Access Technology (NR) operating in the frequency range up to 100 GHz. The first version of the 5G standard was completed at the end of 2017, allowing for the prototyping and commercial deployment of 5G NR compliant devices (e.g., smartphones).

[0013] For example, the system architecture assumes a Next Generation Radio Access Network (NG-RAN) with gNBs. The gNBs provide UE-side termination of NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols. The gNBs are connected to each other via an Xn interface. The gNBs are also connected to a Next Generation Core (NGC) via a Next Generation (NG) interface, more specifically to an Access and Mobility Management Function (AMF) (e.g., a specific core entity that performs AMF) via an NG-C interface, and to a User Plane Function (UPF) (e.g., a specific core entity that performs UPF) via an NG-U interface. The NG-RAN architecture is shown in Figure 1 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0014] The NR user plane protocol stack (see, for example, 3GPP TS 38.300, section 4.4.1) includes the Packet Data Convergence Protocol (PDCP) sublayer (see, for example, TS 38.300, section 6.4), the Radio Link Control (RLC) sublayer (see, for example, TS 38.300, section 6.3), and the Medium Access Control (MAC) sublayer (see, for example, TS 38.300, section 6.2), which are terminated on the network side at the gNB. A new Access Stratum (AS) sublayer (Service Data Adaptation Protocol (SDAP)) has also been introduced on top of PDCP (see, for example, 3GPP TS 38.300, section 6.5). A control plane protocol stack has also been defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of Layer 2 functions is given in Section 6 of TS 38.300. The functions of the PDCP sublayer, RLC sublayer, and MAC sublayer are listed in clauses 6.4, 6.3, and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in clause 7 of TS 38.300.

[0015] For example, the Medium-Access-Control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling various numerologies.

[0016] For example, the physical layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. The physical layer also handles mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for transmitting a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include the Physical Random Access Channel (PRACH), the Physical Uplink Shared Channel (PUSCH), and the Physical Uplink Control Channel (PUCCH) as uplink physical channels, and the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH), and the Physical Broadcast Channel (PBCH) as downlink physical channels.

[0017] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in the downlink and 10 Gbps in the uplink) and effective (user-experienced) data rates approximately three times higher than those offered by IMT-Advanced. Meanwhile, URLLC imposes stricter requirements for ultra-low latency (0.5 ms user-plane latency for both UL and DL) and high reliability (1-10-5 within 1 ms). Finally, mMTC may require preferably high connection density (1,000,000 devices / km2 in urban environments), wide coverage in adverse environments, and extremely long battery life (15 years) for low-cost devices.

[0018] Therefore, OFDM numerology (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case may not be valid for another use case. For example, low-latency services may preferably require a shorter symbol length (and therefore a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also referred to as TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with small delay spreads. Subcarrier spacing may be optimized accordingly to maintain similar CP overhead. NR may support one or more subcarrier spacing values. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, etc. are currently considered. The symbol length Tu and subcarrier spacing Δf are directly related by the equation Δf = 1 / Tu. Similar to LTE systems, the term "resource element" can be used to mean the smallest resource unit consisting of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0019] In the new radio system 5G-NR, a resource grid of subcarriers and OFDM symbols is defined for each numerology and each carrier in the uplink and downlink. Each element of the resource grid is called a resource element and is specified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0020] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 2 shows the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0021] For example, the gNB and ng-eNB host the following main functions: - Radio Resource Management functions such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, dynamic allocation (scheduling) of resources to UEs in both uplink and downlink; - IP header compression, encryption, and integrity protection of data; - AMF selection at UE attach time if routing to the AMF cannot be determined from the information provided by the UE; - Routing of user plane data towards UPF; - Routing of control plane information towards AMF; - Setting up and tearing down connections; - scheduling and sending of paging messages; - Scheduling and transmission of system broadcast information (originating from AMF or Operation, Admission, Maintenance (OAM) Function); - Configuring measurements and measurement reporting for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Network slicing support; - QoS flow management and mapping to data radio bearers; - Support for UEs in RRC_INACTIVE state; - NAS message delivery function; - Sharing of radio access networks; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0022] The Access and Mobility Management Function (AMF) hosts the following main functions: - Ability to terminate Non-Access Stratum (NAS) signaling; - NAS signaling security; - Access Stratum (AS) security control; - 3GPP Core Network (CN) inter-node signaling for mobility between access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization, including checking roaming privileges; - Mobility management control (subscription and policy); - Network slicing support; - Selection of Session Management Function (SMF).

[0023] Additionally, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT / inter-RAT mobility (if applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and policy rule enforcement for the user plane part; - Traffic usage reporting; - uplink classifier to support routing of traffic flows to the data network; - Branching Point for supporting multi-homed PDU session; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Verification of uplink traffic (mapping to the QoS flow of the SDF); - Downlink packet buffering and trigger function for downlink data notification.

[0024] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Enforcement of control part policies and QoS; - Notification of downlink data.

[0025] <Procedures for RRC connection setup and reconfiguration> Figure 3 shows some of the interactions between the UE, gNB, and AMF (5GC entity) when the UE moves from RRC_IDLE to RRC_CONNECTED in the NAS part (see TS 38.300 v15.6.0).

[0026] RRC is a higher layer signaling protocol used to configure the UE and the gNB. With this transition, the AMF prepares UE context data (including, for example, PDU session context, security keys, UE radio capabilities, and UE security capabilities) and sends it to the gNB with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding with a SecurityModeComplete message. The gNB then sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures the UE to set up a Signaling Radio Bearer 2 (SRB2) and a Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration steps are omitted because SRB2 and DRB are not set up. Finally, the gNB notifies the AMF that the setup procedure is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0027] Therefore, the present disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) that includes: control circuitry that, in operation, establishes a Next Generation (NG) connection with a gNodeB; and a transmitter that, in operation, transmits an initial context setup message to the gNodeB via the NG connection so that a signaling radio bearer between the gNodeB and a user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling that includes a resource allocation configuration information element (IE) to the UE via the signaling radio bearer. Then, the UE performs uplink transmission or downlink reception based on the resource allocation configuration.

[0028] <IMT usage scenarios from 2020 onwards> Figure 4 illustrates some use cases for 5G NR. The 3rd Generation Partnership Project New Radio (3GPP NR) is considering three use cases envisioned by IMT-2020 to support a wide variety of services and applications. The first phase of specifications for enhanced mobile broadband (eMBB) has been completed. Current and future work includes standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC), in addition to expanding support for eMBB. Figure 4 illustrates some example use scenarios envisioned for IMT beyond 2020 (see, for example, ITU-R M.2083 Figure 2).

[0029] URLLC use cases have stringent performance requirements, such as throughput, latency, and availability. URLLC use cases are envisioned as one of the enabling technologies for future applications, such as wireless control of industrial production or manufacturing processes, remote medical surgery, automated power transmission and distribution in smart grids, and road safety. URLLC's ultra-high reliability is supported by identifying technologies that meet the requirements set by TR 38.913. Key requirements for NR URLLC in Release 15 include a target user plane latency of 0.5 ms on the uplink (UL) and 0.5 ms on the downlink (DL). The overall URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size at a user plane latency of 1 ms.

[0030] From a physical layer perspective, reliability can be improved in many possible ways. Current reliability improvement room includes defining a separate CQI table for URLLC, more compact DCI formats, PDCCH repetition, etc. However, this room can be expanded to achieve ultra-high reliability as NR (with respect to the key requirements of NR URLLC) becomes more stable and developed. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0031] Additionally, technology enhancements targeted by NR URLLC aim to improve latency and reliability. Technology enhancements for latency improvement include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level repetition in the data channel, and preemption in the downlink. Preemption means that a transmission with previously allocated resources is stopped and the allocated resources are used for another transmission with a later requested lower latency / higher priority requirement. Thus, a previously allowed transmission is preempted by a later transmission. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) may be preempted by a transmission of service type B (eMBB, etc.). Technology enhancements for reliability improvement include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0032] The use case for massive machine-type communication (mMTC) is characterized by a very large number of connected devices that typically transmit relatively small amounts of data that are not sensitive to latency. These devices are required to be low cost and have very long battery life. From an NR perspective, using very narrow bandwidth portions is one solution that saves power and allows for long battery life from the UE perspective.

[0033] As mentioned above, the scope of reliability improvement in NR is expected to be broader. One of the key requirements for all cases, for example for URLLC and mMTC, is high or ultra-high reliability. Several mechanisms can improve reliability from a radio perspective and a network perspective. Generally, there are two to three key areas that can help improve reliability. These areas include compact control channel information, data channel / control channel repetition, and diversity in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvement regardless of the specific communication scenario.

[0034] For NR URLLC, further use cases with more stringent requirements are envisioned, such as factory automation, transportation, and power distribution: high reliability (up to 10-6 level), high availability, packet sizes up to 256 bytes, and time synchronization down to a few μs (depending on the use case, the value can be 1 μs or a few μs depending on the frequency range and low latency in the 0.5 ms to 1 ms range (e.g., 0.5 ms latency on the targeted user plane)).

[0035] Furthermore, for NR URLLC, several technical enhancements are possible from the perspective of the physical layer. These technical enhancements include the enhancement of the PDCCH (Physical Downlink Control Channel) related to compact DCI, the repetition of the PDCCH, and the increase in PDCCH monitoring. Also, the enhancement of UCI (Uplink Control Information) is related to the enhancement of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. In addition, there may be enhancements to PUSCH related to mini-slot level hopping, and enhancements to retransmission / repetition. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0036] <QoS Control> The 5G QoS (Quality of Service) model is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR: Guaranteed Bit Rate QoS flow) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flow). Therefore, at the NAS level, a QoS flow is the finest granularity QoS classification in a PDU session. A QoS flow is identified within a PDU session by a QoS Flow ID (QFI: QoS Flow ID) that is carried in an encapsulation header via the NG-U interface.

[0037] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearer (DRB) for each PDU session, e.g., as shown above with reference to Figure 3. Additional DRBs for the QoS flows of that PDU session can be configured later (when this is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in the UE and the 5GC associate UL and DL packets with QoS flows, while AS-level mapping rules in the UE and the NG-RAN associate UL and DL QoS flows with DRBs.

[0038] Figure 5 shows the 5G NR non-roaming reference architecture (see TS 23.501 v16.1.0, section 4.23). An Application Function (AF) (e.g., an external application server hosting 5G services, as illustrated in Figure 4) interacts with the 3GPP core network to provide services. For example, it accesses a Network Exposure Function (NEF) to support applications that affect traffic routing, or interacts with a policy framework (see Policy Control Function (PCF)) for policy control (e.g., QoS control). Based on the operator's deployment, Application Functions that are considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions that are not authorized by the operator to directly access Network Functions interact with the relevant Network Functions using the external exposure framework via the NEF.

[0039] Figure 5 further illustrates further functional units of the 5G architecture, namely, Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator-provided services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and run in a cloud computing environment.

[0040] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, in operation, sends a request including QoS requirements for at least one of a URLLC service, an eMMB service, and an mMTC service to at least one of 5GC functions (e.g., an NEF, an AMF, an SMF, a PCF, an UPF, etc.) to establish a PDU session including a radio bearer between a gNodeB and a UE according to the QoS requirements; and a control circuit that, in operation, performs a service using the established PDU session.

[0041] [Expansion to non-terrestrial networks (NTN)] Rel. 15 is a specification for radio access technology for terrestrial networks, for example. On the other hand, NR is being considered for extension to non-terrestrial networks (NTNs), such as communications using satellites or high-altitude platform stations (HAPSs) (see, for example, Non-Patent Document 1). An example of an NTN is communications for aircraft or ships (for example, satellite communications).

[0042] In the following, 5G NR technology extended to NTN may be referred to as "5G NTN."

[0043] In an NTN environment, a satellite's coverage area (e.g., one or more cells) for a ground terminal or a terminal installed on an aircraft (hereinafter sometimes referred to as an "aircraft terminal") is formed, for example, by a beam transmitted from the satellite.

[0044] For example, satellite communications are used for communication between aircraft and ground networks. As an example, aircraft terminals are capable of Internet access (or broadband communications).

[0045] Additionally, the use of Internet of Things (IoT) terminals (also called IoT devices), such as sensors, in various locations on the ground is being considered. Examples of the use of IoT terminals include the location management and control of containers or heavy machinery, or the sensing and monitoring of natural conditions such as rivers or forests. Note that the coverage areas of terrestrial networks tend to be formed mainly in residential or activity areas, so satellite communications can be used, for example, for communications with IoT terminals in remote areas outside the coverage areas of terrestrial networks.

[0046] 5G NR can handle various types of communication traffic, such as broadband communication (e.g., enhanced Mobile Broadband: eMBB) or IoT communication (e.g., massive Machine Type Communication: mMTC). 5G NTN can also handle communication for aircraft (e.g., broadband communication) and communication for IoT devices.

[0047] Here, the beam area formed by a satellite can extend, for example, to several hundred kilometers, so it is expected that the beam area formed by the satellite can accommodate a larger number of IoT terminals.

[0048] However, methods for improving the transmission efficiency of communications for aircraft and IoT terminals in the NTN environment have not been fully explored.

[0049] Therefore, in one embodiment of the present disclosure, a method for improving the transmission efficiency of communications to aircraft and communications to IoT terminals is described. According to the embodiment of the present disclosure, a decrease in the throughput of communications to aircraft can be suppressed, and more IoT terminals can be accommodated.

[0050] [Multiple Access Method] Multiple access methods in cellular networks include, for example, Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA). OMA, for example, transmits data to each user using different time and frequency resources. On the other hand, NOMA, for example, transmits data to each user with different power levels superimposed on the same time and frequency resources.

[0051] In NOMA, one receiver removes high-power signals (i.e., interference signals) from the superimposed signals using, for example, a serial interference canceller (SIC) to extract low-power signals (i.e., desired signals). Another receiver treats low-power signals as noise and decodes high-power signals from the superimposed signals. NOMA can improve transmission efficiency compared to OMA by using the same time and frequency resources.

[0052] Here, for example, in satellite communications, the propagation path of an aircraft (e.g., the propagation path between a satellite and an aircraft terminal) may be an environment with fewer reflectors and less fading (e.g., an additive white Gaussian noise (AWGN) environment) compared to the propagation path of a ground terminal. Therefore, the received signal is less likely to be distorted on the aircraft or satellite in the aircraft propagation path. Therefore, NOMA can improve the accuracy of interference cancellation by SIC in aircraft-directed communications.

[0053] On the other hand, for example, in satellite communications, the propagation path of an IoT terminal (e.g., the propagation path between a satellite and an IoT terminal) may be in an environment (e.g., a multipath environment) that is more susceptible to the influence of reflectors on the ground than the propagation path of an aircraft. As a result, in the propagation path of the IoT terminal, the received signal is likely to be distorted at the IoT terminal or the satellite. Furthermore, in the propagation path of the IoT terminal, the received signal may be attenuated by natural influences such as clouds or rain. Therefore, in NOMA, the accuracy of interference cancellation by SIC in communications for IoT terminals is likely to decrease.

[0054] Therefore, in one embodiment of the present disclosure, NOMA multiplexing is performed between different terminal types. As an example, as described above, NOMA multiplexing is performed between signals for aircraft terminals with good propagation path quality and signals for IoT terminals whose propagation path quality is prone to deterioration. This, for example, can suppress a decrease in throughput of communications for aircraft and accommodate more IoT terminals.

[0055] (Embodiment 1) [Wireless communication system overview] A wireless communication system according to an embodiment of the present disclosure includes, for example, at least a base station 100, a terminal 200, and a terminal 300. The wireless communication system may be, for example, a satellite communication system in an NTN environment or another wireless communication system. The base station 100, the terminal 200, and the terminal 300 are examples of communication devices.

[0056] For example, the terminal 200 may be an aircraft terminal, and the terminal 300 may be an IoT terminal.

[0057] Fig. 6 is a block diagram showing a configuration example of a portion of base station 100 according to an embodiment of the present disclosure. In base station 100 shown in Fig. 6, control unit 11 (e.g., corresponding to a control circuit) allocates first transmission power to a first signal corresponding to a first terminal type and allocates second transmission power to a second signal corresponding to a second terminal type in non-orthogonal multiplexing (e.g., NOMA multiplexing). Communication unit 12 (e.g., corresponding to a communication circuit) transmits the non-orthogonally multiplexed first and second signals.

[0058] 6, communication unit 12 (e.g., corresponding to a receiving circuit) receives a non-orthogonal multiplexed signal. Control unit 11 (equivalent to a control circuit) removes one of a first signal with a first reception power corresponding to a first terminal type and a second signal with a second reception power corresponding to a second terminal type from the non-orthogonal multiplexed signal.

[0059] 7 is a block diagram showing a partial configuration example of terminal 200 according to an embodiment of the present disclosure. In terminal 200 shown in FIG. 7, communication unit 22 (equivalent to, for example, a receiving circuit) receives a non-orthogonal multiplexed signal. Control unit 21 (equivalent to a control circuit) removes one of a first signal with a first reception power corresponding to a first terminal type and a second signal with a second reception power corresponding to a second terminal type from the non-orthogonal multiplexed signal.

[0060] [Base station configuration] Fig. 8 is a block diagram showing an example configuration of base station 100. Base station 100 shown in Fig. 8 includes, for example, a data generation unit 101, a data transmission processing unit 102, a data generation unit 103, a data transmission processing unit 104, a NOMA multiplexing unit 105, a control information generation unit 106, a control information transmission processing unit 107, a radio transmission unit 108, an antenna 109, a radio reception unit 110, and a reception processing unit (or an interference removal unit) 111.

[0061] For example, the data generation units 101 and 103, the data transmission processing units 102 and 104, the NOMA multiplexing unit 105, the control information generation unit 106, the control information transmission processing unit 107, and the reception processing unit 111 shown in FIG. 8 may correspond to the control unit 11 shown in FIG. 6, and the radio transmission unit 108, the antenna 109, and the radio reception unit 110 shown in FIG. 8 may correspond to the communication unit 12 shown in FIG. 6.

[0062] The data generation unit 101 generates, for example, user data (hereinafter also referred to as “aircraft-oriented data”) intended for an aircraft terminal (for example, terminal 200), and outputs the generated data signal to the data transmission processing unit .

[0063] The data transmission processing unit 102 performs error correction coding and modulation such as Quadrature Phase Shift Keying (QPSK) or 16 Quadrature Amplitude Modulation (16QAM) on the data signal input from the data generation unit 101 to generate a modulated signal. The data transmission processing unit 102 outputs the generated modulated signal to the NOMA multiplexing unit 105.

[0064] The data generation unit 103 generates, for example, user data (hereinafter also referred to as “IoT-oriented data”) for an IoT terminal (for example, the terminal 300), and outputs the generated data signal to the data transmission processing unit 104.

[0065] The data transmission processing unit 104 generates a modulated signal by performing error correction coding and modulation such as QPSK or 16QAM on the data signal input from the data generation unit 103. The data transmission processing unit 104 outputs the generated modulated signal to the NOMA multiplexing unit 105.

[0066] The NOMA multiplexing unit 105 performs NOMA multiplexing on the modulated signal (e.g., data for aircraft) input from the data transmission processing unit 102 and the modulated signal (e.g., data for IoT) input from the data transmission processing unit 104. For example, the NOMA multiplexing unit 105 sets power for the data for aircraft and the data for IoT, and superimposes them on the same time and frequency resources. For example, the NOMA multiplexing unit 105 may set a higher transmission power for the data for IoT than for the data for aircraft. Furthermore, the NOMA multiplexing unit 105 may perform terminal-specific or terminal type-specific scrambling on the data for aircraft and the data for IoT, respectively. The NOMA multiplexing unit 105 outputs the signal on which the data for aircraft and the data for IoT are superimposed to the wireless transmission unit 108.

[0067] The control information generating unit 106 generates a control signal including information such as system information or control information relating to each of the terminals 200 and 300 (for example, individual control information for data allocation), and outputs the generated control signal to the control information transmission processing unit 107.

[0068] The control information may include, for example, information indicating allocation of the same time and frequency resources to an IoT terminal (for example, terminal 300) and an aircraft terminal (for example, terminal 200). Furthermore, the control information for the aircraft terminal may include, for example, information indicating whether IoT-oriented data is superimposed, or information such as modulation, coding rate, reference signal pattern, or scrambling sequence of the IoT terminal-oriented data (in other words, information related to SIC processing).

[0069] Control information transmission processing section 107 performs error correction coding and modulation on the control signal input from control information generating section 106 to generate a modulated signal. Control information transmission processing section 107 outputs the generated modulated signal to radio transmitting section 108.

[0070] The radio transmission unit 108 performs radio transmission processing such as D / A conversion, up-conversion, and amplification on the signal input from the NOMA multiplexing unit 105 and the signal input from the control information transmission processing unit 107, and transmits the radio signal after radio transmission processing from the antenna 109.

[0071] The wireless receiving unit 110 performs wireless receiving processing such as down-conversion and A / D conversion on data signals received via the antenna 109 from at least one of the aircraft terminal (terminal 200) and the IoT terminal (terminal 300), and outputs the received signals after wireless receiving processing to the reception processing unit 111. For example, the signals received at the base station 100 may include signals (e.g., NOMA multiplexed signals) transmitted from the aircraft terminal and the IoT terminal using the same time and frequency resources.

[0072] The reception processing unit 111 performs reception processing such as channel estimation, descrambling, demodulation, and decoding on the received signal from the aircraft terminal, and acquires received data from the aircraft terminal.

[0073] Furthermore, when performing data reception processing on a received signal from an IoT terminal, the reception processing unit 111 performs, for example, interference removal reception (e.g., SIC processing). For example, the reception processing unit 111 performs processing such as encoding, modulation, and multiplication by a channel coefficient on the received data acquired from the aircraft terminal to generate a received signal replica. The reception processing unit 111 acquires the received signal from the IoT terminal by subtracting the received signal replica from the received signal input from the wireless reception unit 110 (in other words, removing data intended for the aircraft). The reception processing unit 111 demodulates and decodes the acquired received signal from the IoT terminal to acquire the received data from the IoT terminal.

[0074] [Configuration of Terminal 200] Fig. 9 is a block diagram showing an example of the configuration of terminal 200 (for example, an aircraft terminal). Terminal 200 shown in Fig. 9 performs interference cancellation (for example, SIC processing) when performing data reception processing.

[0075] The terminal 200 shown in FIG. 9 includes, for example, an antenna 201, a radio receiving unit 202, a control information receiving processing unit 203, a data receiving processing unit (or an interference removing unit) 204, a data generating unit 205, a data transmitting processing unit 206, and a radio transmitting unit 207.

[0076] Radio receiving section 202 performs radio reception processing such as down-conversion and A / D conversion on signals received from base station 100 via antenna 201. Of the received signals after radio reception processing, radio receiving section 202 outputs control signals to control information reception processing section 203 and outputs data signals to data reception processing section 204.

[0077] Here, the data signal received by the terminal 200 may include, for example, a signal in which aircraft-oriented data and IoT-oriented data are superimposed in the same time and frequency resource (for example, a NOMA-multiplexed signal).

[0078] The control information reception processing unit 203 performs reception processing such as channel estimation, demodulation, and decoding on the control signal input from the radio reception unit 202, and acquires resource allocation information for at least one of the downlink and the uplink. For example, the control information reception processing unit 203 outputs the downlink resource allocation information to the data reception processing unit 204, and outputs the uplink resource allocation information to the data transmission processing unit 206.

[0079] When performing data reception processing, the data reception processing unit 204 performs, for example, interference removal reception (e.g., SIC processing). For example, the data reception processing unit 204 performs reception processing such as channel estimation, descrambling, demodulation, and decoding on signals intended for an IoT terminal (terminal 300) out of the data signals input from the wireless reception unit 202, to acquire received data intended for the IoT. The data reception processing unit 204 also performs processing such as encoding, modulation, and multiplication by a channel coefficient on the received data intended for the IoT to create a received signal replica. The data reception processing unit 204 then subtracts the received signal replica from the received signal input from the wireless reception unit 202 (in other words, removes the data intended for the IoT) to acquire received data intended for the aircraft terminal (terminal 200).

[0080] The data reception processing unit 204 may perform reception processing in accordance with, for example, time and frequency resources, modulation schemes, or encoding methods included in the downlink resource allocation information input from the control information reception processing unit 203. The data reception processing unit 204 may output, for example, received data intended for aircraft to a subsequent application processing unit (not shown). The data reception processing unit 204 may also discard, for example, the acquired received data intended for IoT.

[0081] The data generation unit 205 generates a data signal including, for example, user data (for example, data for an aircraft) and outputs the generated data signal to the data transmission processing unit 206.

[0082] The data transmission processing unit 206 performs error correction coding and modulation on the data signal input from the data generation unit 205 to generate a modulated signal. For example, the data transmission processing unit 206 may perform error correction coding and modulation such as QPSK or 16QAM based on the uplink resource allocation information input from the control information reception processing unit 203. The data transmission processing unit 206 outputs the generated modulated signal to the radio transmission unit 207.

[0083] The radio transmission unit 207 generates a transmission frame by mapping the signal input from the data transmission processing unit 206 to time and frequency resources, performs radio transmission processing such as D / A conversion, up-conversion, and amplification on the transmission frame, and transmits the radio signal after the radio transmission processing from the antenna 201.

[0084] [Configuration of terminal 300] Fig. 10 is a block diagram showing an example configuration of a terminal 300 (IoT terminal). The terminal 300 shown in Fig. 10 does not perform interference cancellation (for example, SIC processing) when performing data reception processing. In other words, the terminal 300 does not need to be equipped with an interference cancellation unit.

[0085] The terminal 300 shown in FIG. 10 includes, for example, an antenna 301, a radio receiving unit 302, a control information receiving processing unit 303, a data receiving processing unit 304, a data generating unit 305, a data transmitting processing unit 306, and a radio transmitting unit 307.

[0086] Radio receiving section 302 performs radio reception processing such as down-conversion and A / D conversion on signals received from base station 100 via antenna 301. Of the received signals after radio reception processing, radio receiving section 302 outputs control signals to control information reception processing section 303 and data signals to data reception processing section 304.

[0087] Here, the data signal received by the terminal 200 may include, for example, a signal in which aircraft-oriented data and IoT-oriented data are superimposed in the same time and frequency resource (for example, a NOMA-multiplexed signal).

[0088] The control information reception processing unit 303 performs reception processing such as channel estimation, demodulation, and decoding on the control signal input from the radio reception unit 302, and acquires resource allocation information for at least one of downlink and uplink. For example, the control information reception processing unit 303 outputs downlink resource allocation information to the data reception processing unit 304, and outputs uplink resource allocation information to the data transmission processing unit 306.

[0089] The data reception processing unit 304 performs reception processing such as channel estimation, descrambling, demodulation, and decoding on the data signal input from the radio reception unit 302, and acquires received data for IoT. Note that the data reception processing unit 304 may perform reception processing in accordance with the time and frequency resources, modulation method, or encoding method included in the downlink resource allocation information input from the control information reception processing unit 303. The data reception processing unit 304 may output the received data for IoT to a subsequent application processing unit (not shown), for example.

[0090] The data generation unit 305 generates a data signal including user data (for example, data for IoT), and outputs the generated data signal to the data transmission processing unit 306.

[0091] The data transmission processing unit 306 performs error correction coding and modulation on the data signal input from the data generation unit 305 to generate a modulated signal. For example, the data transmission processing unit 306 may perform error correction coding and modulation such as QPSK or 16QAM based on the uplink resource allocation information input from the control information reception processing unit 303. The data transmission processing unit 306 outputs the generated modulated signal to the radio transmission unit 307.

[0092] The radio transmission unit 307 generates a transmission frame by mapping the signal input from the data transmission processing unit 306 to time and frequency resources, performs radio transmission processing such as D / A conversion, up-conversion, and amplification on the transmission frame, and transmits the radio signal after the radio transmission processing from the antenna 301.

[0093] [Example of operation of base station 100, terminal 200, and terminal 300] An example of the operation of the above-mentioned base station 100, terminal 200, and terminal 300 will be described.

[0094] First, downlink communication will be described.

[0095] FIG. 11 is a sequence diagram showing an example of the operations of the base station 100, the terminal 200 (for example, an aircraft terminal), and the terminal 300 (for example, an IoT terminal) in downlink communication.

[0096] 11, the base station 100 generates aircraft-oriented data and IoT-oriented data (S101 and S102). The order of generation of the aircraft-oriented data and IoT-oriented data (in other words, generation timing) is not limited to the order shown in FIG. 11, and may be the reverse order or may be generated simultaneously.

[0097] The base station 100 NOMA multiplexes the aircraft-directed data and the IoT-directed data (S103), and transmits the NOMA-multiplexed signals to the terminal 200 and the terminal 300, respectively (S104).

[0098] FIG. 12 is a diagram showing an example of a signal transmitted by the base station 100, in which the aircraft-oriented data and the IoT-oriented data are superimposed.

[0099] For example, in a propagation path between a satellite (e.g., a 5G (NR) satellite) and an IoT terminal (e.g., a container), due to natural influences such as clouds or rainfall, or influences such as reflected waves on the ground, the IoT terminal is more likely to receive a signal with greater attenuation or distortion than in a propagation path between a satellite and an aircraft terminal. On the other hand, in a propagation path between a satellite and an aircraft terminal, there is less likelihood of an obstruction or reflecting object being present in the vicinity, and the aircraft terminal is more likely to receive a signal with less attenuation or distortion than in a propagation path between a satellite and an IoT terminal.

[0100] In other words, in the downlink, the reception quality (for example, Signal to Interference and Noise Ratio (SINR)) at the aircraft terminal tends to be higher than the reception quality at the IoT terminal.

[0101] Therefore, the base station 100 sets the transmission power of the IoT-directed data higher than the transmission power of the aircraft-directed data, as shown in Fig. 12. Then, the base station 100 NOMA-multiplexes (in other words, superimposes) the aircraft-directed data and the IoT-directed data and transmits them based on the set transmission power.

[0102] In the terminal 200 (for example, an aircraft terminal), the high-power IoT data can become an interference signal with the low-power aircraft data. Therefore, the terminal 200 removes the signal component of the IoT data (in other words, the interference signal component) from the signal transmitted from the base station 100 (S105 in FIG. 11), and demodulates and decodes the signal after interference removal to extract the aircraft data (S106 in FIG. 11).

[0103] For example, an interference canceller (SIC) may be used to remove the IoT-directed data. As described above, the propagation path between the satellite and the aircraft terminal is almost an AWGN environment, and is therefore less susceptible to fading. Furthermore, the transmission power of the IoT-directed data, which is an interfering signal to the aircraft terminal, is higher than the transmission power of the aircraft-directed data. Therefore, the terminal 200 can receive the IoT-directed data with higher reception quality than, for example, the terminal 300 (e.g., an IoT terminal), and therefore the accuracy of the received signal replica can be improved, and the accuracy of interference removal can be improved. In other words, the terminal 200 can properly receive the aircraft-directed data.

[0104] Furthermore, in the terminal 300 (e.g., IoT terminal), the data intended for the aircraft may become an interference signal. However, as shown in FIG. 12, the transmission power of the data intended for the aircraft is lower than that of the data intended for the IoT. Therefore, the data intended for the aircraft received by the terminal 300 may be at a level equivalent to noise generated in the receiver or adjacent cell interference. Therefore, the terminal 300 may perform reception processing (e.g., demodulation and decoding) of the data intended for the IoT terminal without performing interference cancellation on the data intended for the aircraft (S107 in FIG. 11). This reception processing allows the terminal 300 to properly receive the data intended for the IoT.

[0105] Next, uplink communication will be described.

[0106] FIG. 13 is a sequence diagram showing an example of the operations of the base station 100, the terminal 200 (for example, an aircraft terminal), and the terminal 300 (for example, an IoT terminal) in uplink communication.

[0107] 13, the terminal 200 generates data for the aircraft (S201). The terminal 300 generates data for the IoT (S202). Note that the timing at which the data for the aircraft and the data for the IoT are generated in the terminal 200 and the terminal 300, respectively, is not limited to the same timing as shown in FIG. 13, and may be different timings.

[0108] The terminal 200 transmits data for the aircraft to the base station 100 (S203-1), and the terminal 300 transmits data for IoT to the base station 100 (S203-2). Through these transmissions, the data for the aircraft and the data for IoT are NOMA multiplexed. Note that, for example, the terminal 200 and the terminal 300 may control NOMA multiplexing based on control information (not shown) including parameters for NOMA multiplexing, such as the transmission timing or transmission power of each piece of data. The terminal 200 and the terminal 300 may, for example, be time-synchronized with respect to data transmission.

[0109] The base station 100 demodulates and decodes, for example, the aircraft-directed data from the received signals (NOMA multiplexed signals) from the terminal 200 and the terminal 300 (S204).

[0110] Furthermore, the base station 100, for example, removes from the received signal an interfering signal component (for example, a signal component of data for aircraft) interfering with the data for IoT (S205), and demodulates and decodes the signal after interference removal to extract the data for IoT (S206). For example, an interference canceller (SIC) may be used to remove the data for aircraft.

[0111] FIG. 14 is a diagram showing an example of a signal received by the base station 100, in which the aircraft-directed data and the IoT-directed data are superimposed.

[0112] As described above, in a propagation path between a satellite (e.g., a 5G (NR) satellite) and an IoT terminal (e.g., a container), the satellite is more likely to receive signals with greater attenuation or distortion than in a propagation path between the satellite and an aircraft terminal due to natural influences such as clouds or rainfall, or influences such as reflected waves on the ground. On the other hand, in a propagation path between a satellite and an aircraft terminal, there is less likelihood of obstructions or reflectors being present in the vicinity, and the satellite is more likely to receive signals with less attenuation or distortion than in a propagation path between a satellite and an IoT terminal. Furthermore, aircraft antennas generally have higher output and better directional performance than IoT terminal antennas.

[0113] In other words, in the uplink, the reception quality (e.g., SINR) of the signal from the aircraft terminal at the satellite tends to be higher than the reception quality of the signal from the IoT terminal. Therefore, for example, the transmission power of the IoT-oriented data at the terminal 300 may be set higher than the transmission power of the aircraft-oriented data at the terminal 200 (not shown).

[0114] On the other hand, for example, it may be assumed that the distance between the satellite and the aircraft terminal is closer than the distance between the satellite and the IoT terminal (for example, a ground terminal). Therefore, as shown in Fig. 14, the received power of the data for the aircraft at the base station 100 may be greater than the received power of the data for the IoT.

[0115] In this way, the propagation path between the satellite and the terminal 200 (aircraft terminal) is almost an AWGN environment, which is less susceptible to fading, and the received power of the aircraft-directed data, which is an interfering signal to the IoT terminal-directed data, is higher than the received power of the IoT terminal-directed data. Therefore, the base station 100 can receive the aircraft-directed data with higher reception quality than the IoT-directed data, for example, and can improve the accuracy of the received signal replica and the accuracy of interference removal. In other words, the base station 100 can properly receive the IoT-directed data.

[0116] Furthermore, in the base station 100, the IoT-oriented data may become an interfering signal with the aircraft-oriented data. However, as shown in FIG. 14, the received power of the IoT-oriented data is lower than that of the aircraft-oriented data. Therefore, the IoT-oriented data received by the base station 100 may be at a level equivalent to noise generated in the receiver or other-cell interference. Therefore, the base station 100 may perform reception processing of the aircraft-oriented data without performing interference removal on the IoT-oriented data. This reception processing allows the terminal 200 to properly receive the aircraft-oriented data.

[0117] As described above, in the present embodiment, in downlink, base station 100 assigns a first transmission power to a signal corresponding to IoT-oriented communication and a second transmission power to a signal corresponding to communication for aircraft in non-orthogonal multiplexing (for example, NOMA multiplexing), and transmits the non-orthogonal multiplexed signal. Furthermore, terminal 200 receives the non-orthogonal multiplexed signal in downlink and removes a first signal with a first reception power corresponding to IoT-oriented communication (in other words, a signal corresponding to a different terminal type) from the non-orthogonal multiplexed signal. Furthermore, base station 100 receives the non-orthogonal multiplexed signal in uplink and removes a second signal with a second reception power corresponding to communication for aircraft (in other words, a signal with a second reception power higher than the reception power corresponding to communication for IoT).

[0118] This process enables communication of data for terminals of different terminal types (for example, data for aircraft and data for IoT) using the same time and frequency resources through NOMA multiplexing. Therefore, for example, data for IoT can be transmitted without reducing the time and frequency resources for data for aircraft, thereby suppressing a decrease in throughput of data for aircraft and enabling communication of data for IoT. Therefore, according to this embodiment, it is possible to improve transmission efficiency in a wireless communication system.

[0119] Furthermore, for example, in the interference removal process in downlink communication, IoT-oriented data received by terminal 200 (aircraft terminal) is removed, and in the interference removal process in uplink communication, aircraft-oriented data received by base station 100 is removed. In other words, in both downlink communication and uplink communication, interference removal process is performed on data transmitted and received over the transmission path of the aircraft, which is a propagation path (almost an AWGN environment) with higher transmission power or reception power and higher reception quality than the transmission path of the IoT terminal. This interference removal process can improve the accuracy of the received signal replica of the interference signal component, for example, in both downlink communication and uplink communication, thereby improving the accuracy of interference removal.

[0120] In addition, in this embodiment, for example, in downlink communication, terminal 200 (aircraft terminal) performs interference removal processing, and in uplink communication, base station 100 performs interference removal processing. In other words, terminal 300 (IoT terminal) does not need to perform interference removal processing. This makes it possible to suppress an increase in the amount of reception processing in an IoT terminal such as terminal 200, which can be expected to be smaller in size or lower in cost than other terminals.

[0121] (Embodiment 2) The configurations of the base station and terminal according to the present embodiment may be the same as the configurations of base station 100, terminal 200, and terminal 300 according to the first embodiment.

[0122] In this embodiment, multiple pieces of IoT-oriented data are orthogonally multiplexed in the time or frequency domain within the same frame, and the signal into which multiple pieces of IoT-oriented data are multiplexed and the aircraft-oriented data are non-orthogonally multiplexed (e.g., NOMA multiplexed).

[0123] In the base station 100 according to the present embodiment, the operation of the data transmission process relating to IoT-oriented data is different from that in the first embodiment.

[0124] For example, in the base station 100 (FIG. 9), the data transmission processing unit 104 performs transmission processing such as encoding and modulation on multiple pieces of IoT-oriented data, and multiplexes the multiple pieces of IoT-oriented data in the time or frequency domain. For example, in the case of frequency division multiplexing (FDM), the data transmission processing unit 104 may map each piece of IoT-oriented data to a resource block (in other words, a unit obtained by dividing a frequency band into multiple pieces), which is an example of a different frequency resource. Alternatively, in the case of time division multiplexing (TDM), the data transmission processing unit 104 may map each piece of IoT-oriented data to a minislot (in other words, a unit obtained by dividing a time frame or a time slot into multiple pieces), which is an example of a different time resource. Note that the resource unit into which IoT-oriented data is multiplexed is not limited to the above example, and may be another resource unit.

[0125] First, downlink communication will be described.

[0126] FIG. 15 is a diagram showing an example of a signal in which aircraft-oriented data and IoT-oriented data are superimposed, the signal being transmitted from the base station 100 in the downlink.

[0127] 15, data for IoT is orthogonally multiplexed onto different resources in the frequency domain. For example, in 5G NTN, resource allocation is performed in resource block units, so each piece of data for IoT may be mapped to a different resource block.

[0128] The base station 100 may encode and modulate the multiple pieces of orthogonally multiplexed IoT-oriented data according to, for example, Method 1 or Method 2 shown in FIG.

[0129] In method 1 of Fig. 16, the base station 100 controls the coding and modulation individually for each piece of IoT-oriented data for each of multiple terminals 300 (terminals 1 to N in Fig. 16). For example, as shown in Fig. 16, in method 1, a cyclic redundancy check (CRC) bit may be added to the IoT-oriented data for each of terminals 1 to N.

[0130] In the case of method 1, the terminal 200 (for example, an aircraft terminal) performs demodulation, decoding, and replica generation processing on each piece of IoT-oriented data superimposed by NOMA multiplexing, and performs interference cancellation on the IoT-oriented data. The terminal 200 may perform interference cancellation processing based on control information such as a modulation method or coding rate for each terminal 300 (IoT terminal) notified from the base station 100, for example.

[0131] In method 1, each terminal 300 (for example, an IoT terminal) may demodulate and decode, among the IoT-oriented data that is NOMA-multiplexed, the IoT-oriented data for that terminal 300. In other words, in method 1, each terminal 300 does not need to demodulate and decode IoT-oriented data for other terminals 300.

[0132] In method 2 of FIG. 16, the base station 100 controls the encoding and modulation of a set of IoT-oriented data for multiple terminals 300 (terminals 1 to N in FIG. 16). For example, the base station 100 may concatenate multiple IoT-oriented data and collectively encode and modulate the concatenated data. For example, as shown in FIG. 16, in method 2, CRC bits may be added to concatenated data obtained by concatenating IoT-oriented data for multiple terminals 1 to N. According to method 2, for example, the amount of CRC bits can be reduced and the size of IoT-oriented data can be increased compared to method 1, thereby improving the coding gain.

[0133] In the case of method 2, the terminal 200 (for example, an aircraft terminal) may perform demodulation, decoding, and replica generation processing on each IoT-oriented data superimposed by NOMA multiplexing collectively (for example, once), and may perform interference cancellation on the IoT-oriented data. Method 2 reduces the processing in the terminal 200 compared to method 1.

[0134] In method 2, for example, base station 100 may notify one piece of control information, such as a modulation scheme or a coding rate, to terminal 200 for multiple terminals 300 (IoT terminals). By this notification, method 2 can reduce the amount of control information compared to method 1.

[0135] Next, uplink communication will be described.

[0136] FIG. 17 is a diagram showing an example of a signal in which aircraft-directed data and IoT-directed data signals are superimposed, which is received by the base station 100 in the uplink.

[0137] 17, data for IoT is orthogonally multiplexed onto different resources in the frequency domain. For example, in 5G NTN, resource allocation is performed in resource block units, so each piece of data for IoT may be mapped to a different resource block.

[0138] Furthermore, as shown in FIG. 17, since the propagation path differs for each IoT terminal, the received power at the base station 100 may also differ for each IoT terminal.

[0139] In the uplink, in the reception process of the IoT-oriented data, the base station 100 performs, for example, demodulation, decoding, and replica generation processes on the aircraft-oriented data, and performs interference cancellation on the aircraft-oriented data.

[0140] Then, the base station 100 demodulates and decodes the received data from each IoT terminal in the received signal from which the aircraft-directed data has been removed, and obtains the received data from each IoT terminal.

[0141] The base station 100 may transmit information regarding resource allocation of multiple pieces of orthogonally multiplexed IoT-oriented data to the terminal 300 (IoT terminal).

[0142] For example, base station 100 may transmit information regarding resource allocation to each terminal 300 individually.

[0143] Alternatively, base station 100 may transmit, for example, information related to resource allocation collectively to multiple orthogonally multiplexed terminals 300. Base station 100 may transmit, for example, information related to resource allocation by group common control information (for example, Group Common Downlink Control Information (DCI)). In this case, base station 100 may notify multiple terminals 300 of one piece of control information.

[0144] Alternatively, the base station 100 may, for example, notify each terminal 300 in advance of the resource blocks to be allocated to each terminal 300. For example, the base station 100 may notify the transmission timing of the uplink signal using group common control information. In this case, resource allocation information for multiple IoT terminals does not need to be included in the group common control information every time allocation is made, and therefore the number of information bits for notification (in other words, overhead) can be reduced.

[0145] As shown in Figures 15 and 17, multiple pieces of IoT-directed data are orthogonally multiplexed in the frequency domain and non-orthogonally multiplexed with data intended for aircraft. This multiplexing allows the IoT terminal to, for example, extract the IoT-directed data allocated to the orthogonal resources. In other words, it is not necessary to perform interference removal processing between IoT terminals. Furthermore, similar to the first embodiment, the IoT terminal is also not required to perform interference removal processing for data intended for aircraft in NOMA multiplexing. Therefore, according to this embodiment, it is possible to suppress an increase in the amount of reception processing of the IoT terminal and to multiplex more IoT-directed data for one piece of aircraft-directed data. Therefore, according to this embodiment, it is possible to improve transmission efficiency in wireless communication.

[0146] 15 and 17, the FDM has been described, but the resource onto which a plurality of IoT-oriented data are multiplexed (in other words, the orthogonal resource) is not limited to the frequency resource, and may be other resource. For example, the plurality of IoT-oriented data may be TDMed or multiplexed by spreading codes (Code Division Multiplexing: CDM).

[0147] Furthermore, in the present embodiment, a case where multiple pieces of IoT-oriented data are orthogonally multiplexed has been described, but the present invention is not limited to this, and signals for multiple terminals may be orthogonally multiplexed in at least one of the IoT-oriented communication and the aircraft-oriented communication. For example, a signal in which multiple pieces of aircraft-oriented data are orthogonally multiplexed (for example, FDM, TDM, or CDM) and the IoT-oriented data may be NOMA-multiplexed.

[0148] The embodiments of the present disclosure have been described above.

[0149] [Other embodiments] (1) In each of the above-described embodiments, for example, variations may occur in the timing of occurrence of communication traffic between aircraft terminals (e.g., terminal 200) and IoT terminals (e.g., terminal 300). Therefore, for example, as shown in FIG. 18, even when data for an IoT terminal is generated, base station 100, terminal 200, or terminal 300 may wait until data for the aircraft terminal is generated before multiplexing and transmitting the data. In other words, IoT-oriented data generated before the transmission timing of data for the aircraft may be NOMA-multiplexed (non-orthogonal multiplexed) at the transmission timing of the data for the aircraft.

[0150] In FIG. 18, for example, even when data for IoT terminal 1 and IoT terminal 2 is generated, these data are superimposed and transmitted when data for the aircraft terminal is generated.

[0151] For example, in the case of downlink, when data for IoT occurs, the base station 100 may wait until data for aircraft occurs, and then perform data allocation to both the IoT terminal and the aircraft terminal.

[0152] Furthermore, for example, in the case of uplink, when base station 100 receives a scheduling request from terminal 300 (IoT terminal), it may wait until it receives a scheduling request from terminal 200 (aircraft terminal), and then allocate data to both terminal 200 and terminal 300. The scheduling request is a signal for notifying base station 100 that uplink data exists in terminal 200 or terminal 300.

[0153] This process allows interference caused to other cells by at least one of the IoT data and the aircraft data to be contained within local time or frequency resources, thereby reducing the impact of interference on other cells. Note that the process shown in Fig. 18 causes delays in the transmission of the IoT data. However, since IoT data generally does not require immediacy, it is less susceptible to the impact of delays in the IoT data. Furthermore, the process shown in Fig. 18 may be applied to, for example, a terminal that can tolerate delays.

[0154] (2) In the above-described embodiments, both downlink and uplink communications have been described, but an embodiment of the present disclosure may be applied to either the downlink or the uplink. For example, of the downlink and the uplink, an embodiment of the present disclosure may be applied to the uplink, which is more likely to generate IoT traffic.

[0155] (3) In the above-described embodiments, the case where data for IoT is multiplexed over the entire bandwidth of the resources allocated to the data for aircraft (for example, FIG. 12, FIG. 14, FIG. 15, or FIG. 17) has been described, but the present invention is not limited to this. For example, data for IoT terminals may be multiplexed over a portion of the bandwidth of the resources allocated to the data for aircraft.

[0156] (3) NOMA is more effective (e.g., improves interference cancellation accuracy) when multiplexing between terminals with different propagation attenuation. Therefore, among multiple IoT terminals, IoT terminals in worse propagation environments and aircraft terminals are multiplexed using NOMA, while IoT terminals in better propagation environments do not need to be multiplexed using NOMA.

[0157] For example, a cell formed by a satellite may be set to a radius of several hundred kilometers. Therefore, within a satellite cell, depending on the location of the terrestrial terminal 300, there may be terminals that are affected by natural factors such as clouds or rainfall and terminals that are not affected. Therefore, for example, an aircraft (terminal 200) that is not affected by attenuation due to clouds or rainfall and an IoT terminal (terminal 300) that is affected by attenuation due to clouds or rainfall may be multiplexed using NOMA. In other words, the IoT terminal (terminal 300) that is not affected by attenuation due to clouds or rainfall does not need to be multiplexed using NOMA. The presence of clouds may be determined by radar from the satellite, and weather-related information may be reported to the base station 100 from the aircraft or IoT terminal.

[0158] (4) The propagation path conditions between the satellite and the aircraft may change depending on the altitude of the aircraft. For example, at an altitude of around 8 to 10 km, where stable flight is possible, the propagation path between the satellite and the aircraft is not obstructed by clouds and provides a good propagation environment. However, at low altitudes below 8 km, attenuation due to the influence of clouds may occur. Therefore, the base station 100 may determine whether to perform NOMA multiplexing based on the altitude of the aircraft (or the terminal 200). For example, the base station 100 may decide to perform NOMA multiplexing when the aircraft's altitude is 8 km or higher, and may decide not to perform NOMA multiplexing when the aircraft's altitude is below 8 km. Note that information regarding the aircraft's altitude may be notified to the base station 100 from the aircraft (or the terminal 200).

[0159] (5) In each of the above-described embodiments, each terminal (for example, terminal 200 or terminal 300) may notify the base station 100 of information related to the terminal type, such as an IoT terminal or an aircraft terminal. The information related to the terminal type may be notified, for example, at the time of initial connection. This notification enables the base station 100 to distinguish the types of terminals to be multiplexed using NOMA.

[0160] (6) In each of the above-described embodiments, the satellite communication system may be configured such that the functions of base station 100 are present on a satellite (e.g., a “regenerative satellite”), or such that the functions of base station 100 are present in a terrestrial gateway (GW) and the satellite relays signals from the GW (e.g., a “transparent satellite”).

[0161] (7) In the above-described embodiments, a satellite communication environment has been described as an example of an NTN environment, but the present disclosure is not limited to this. For example, an embodiment of the present disclosure may be applied to non-terrestrial communications such as pseudolites at altitudes of several tens of kilometers, HAPS, or drones.

[0162] Although the above-described embodiments have been described using an NTN environment (e.g., a satellite communication environment) as an example, the present disclosure is not limited thereto. The present disclosure may be applied to other communication environments (e.g., an LTE and / or NR terrestrial cellular environment).

[0163] (8) In the above-described embodiments, communication for an aircraft terminal has been described, but the type of terminal is not limited to this and may be, for example, a terminal that performs broadband communication. For example, an embodiment of the present disclosure may be applied to, instead of an aircraft terminal, a terminal located on a ship, a train, or a flying object other than an aircraft.

[0164] In addition, although the above-described embodiments have described communication for IoT terminals, the type of terminal is not limited to this, and may be, for example, a terminal that performs low-volume communication. For example, an embodiment of the present disclosure may be applied to an IoT gateway that bundles multiple terminals together for communication, instead of an IoT terminal.

[0165] Furthermore, in each of the above-described embodiments, an example of non-orthogonal multiplexing of an aircraft terminal and an IoT terminal has been described, but the terminal types that are non-orthogonally multiplexed are not limited to the combination of an aircraft terminal and an IoT terminal, and may be, for example, a combination of other terminal types such as the following: a: Terminals used in fading environments and terminals not used in fading environments b: A terminal used in a multipath (reflecting object) environment and a terminal not used in a multipath environment c: Devices used in non-line-of-sight environments and devices used in line-of-sight environments d: A terminal with poor performance (for example, hardware performance) of at least one of transmission / reception and antenna, and a terminal with good hardware performance e: Mobile and stationary terminals f: Terrestrial and non-terrestrial terminals

[0166] For example, a terminal used in a fading environment, a terminal used in a multipath environment, a terminal used in a non-line-of-sight environment, a terminal with poor performance, and a mobile terminal may correspond to terminals whose propagation path quality is likely to deteriorate, similar to the IoT terminals in each of the above-mentioned embodiments. Also, for example, a terminal not used in a fading environment, a terminal not used in a multipath environment, a terminal used in a line-of-sight environment, a terminal with good performance, a stationary terminal, and a non-terrestrial terminal may correspond to terminals whose propagation path quality is good, similar to the aircraft terminals in each of the above-mentioned embodiments.

[0167] Furthermore, the capabilities of terminals may be distinguished based on information such as UE capability, UE category, or UE class.

[0168] (9) In the above-described embodiments, a case has been described in which, in NOMA multiplexing, high transmission power is set for data for IoT and low transmission power is set for data for aircraft, and interference cancellation processing is performed on signals corresponding to the propagation path of the aircraft. However, an embodiment of the present disclosure is not limited to this, and, for example, transmission power setting and interference cancellation processing may be controlled based on the environment (or reception quality) of each terminal that is multiplexed in NOMA.

[0169] For example, for two terminals that are NOMA multiplexed, the propagation path quality of the terminal that is closer to the satellite may be lower than the propagation path quality of the terminal that is farther from the satellite. In this case, high transmission power may be set for data intended for the terminal with lower propagation path quality, and low transmission power may be set for the terminal with better propagation path quality, and interference cancellation processing may be performed on the signal corresponding to the propagation path of the terminal with better propagation path quality.

[0170] As an example, consider a situation where an aircraft enters clouds within a satellite cell, but there are no clouds above the IoT terminal. Under this circumstance, for example, the quality of the propagation path between the satellite and the IoT terminal may be better than that between the satellite and the aircraft terminal. In this case, in NOMA multiplexing, high transmission power may be set for data destined for the aircraft, and low transmission power may be set for data destined for the IoT terminal, and interference cancellation processing may be performed on signals corresponding to the propagation path of the IoT terminal. In this case, the IoT terminal may be equipped with an interference cancellation unit.

[0171] (10) In each of the above-described embodiments, the data for aircraft may be transmitted based on, for example, the NR specifications. The data for IoT may be transmitted based on, for example, the LTE NB-IoT or eMTC specifications or specifications that are extensions of these specifications for NTN.

[0172] (11) In the above-described embodiments, non-orthogonal multiplexing is performed in terminals of different services (e.g., IoT-oriented communication and aircraft-oriented communication), but an embodiment of the present disclosure is not limited to this, and non-orthogonal multiplexing may be performed between terminals of the same service. For example, in either IoT-oriented communication or aircraft-oriented communication (in other words, the same service), NOMA multiplexing may be performed between signals of terminals distinguished by any of the above-described a to f.

[0173] In this case, for example, as in the second embodiment, at least one of the signals to be NOMA multiplexed may be orthogonally multiplexed (for example, FDM, TDM or CDM).

[0174] In NOMA, a received signal replica is generated using data decoded during interference cancellation processing using SIC, but if a decoding error occurs, an accurate replica cannot be generated. When using HARQ, the target packet error rate in the physical layer may be set high to obtain gains from retransmission combining. In this case, the frequency of decoding errors increases, and the accuracy of the replica may deteriorate. On the other hand, in NTN, disabling HARQ is being considered due to long propagation delays. Therefore, NOMA multiplexing may be applied to terminals or HARQ processes with HARQ disabled, and not to terminals or HARQ processes with HARQ enabled. Alternatively, HARQ may be disabled when NOMA multiplexing is performed.

[0175] (12) In the above-described embodiments, non-orthogonal multiplexing transmission between terminals using the same antenna of the same satellite in the downlink has been described, but this is not limiting, and non-orthogonal multiplexing transmission may be performed for signals transmitted from different satellites or different antennas. Furthermore, in the uplink, non-orthogonal multiplexing signals from different terminals may be received by different satellites or different antennas.

[0176] Other embodiments have been described above.

[0177] In addition, the term "terminal" in each of the above-described embodiments may be replaced with the term "UE." Furthermore, the term "base station" may be replaced with the term "eNodeB," "eNB," "gNodeB," or "gNB."

[0178] Furthermore, the notation "··· part" in the above-described embodiments may be replaced with other notations such as "··· circuitry," "··· device," "··· unit," or "··· module."

[0179] The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may be called an IC, system LSI, super LSI, or ultra LSI.

[0180] The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0181] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology is also a possibility.

[0182] The present disclosure may be implemented in any type of apparatus, device, or system (collectively referred to as a communications apparatus) that has a communications function. The communications apparatus may include a wireless transceiver and processing / control circuitry. The wireless transceiver may include a receiver and a transmitter, or both functions. The wireless transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0183] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (such as appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0184] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0185] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0186] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0187] A communication device according to one embodiment of the present disclosure includes a control circuit that, in non-orthogonal multiplexing, allocates a first transmission power to a first signal corresponding to a first terminal type and allocates a second transmission power to a second signal corresponding to a second terminal type, and a transmission circuit that transmits the non-orthogonally multiplexed first signal and second signal.

[0188] In one embodiment of the present disclosure, the first transmission power is higher than the second transmission power.

[0189] In one embodiment of the present disclosure, the transmission circuit performs at least one of orthogonal multiplexing of a plurality of the first signals and orthogonal multiplexing of a plurality of the second signals.

[0190] In one embodiment of the present disclosure, the control circuit controls coding and modulation for each of the plurality of orthogonally multiplexed signals.

[0191] In one embodiment of the present disclosure, the control circuit controls coding and modulation of the set of orthogonally multiplexed signals.

[0192] In one embodiment of the present disclosure, the control circuit non-orthogonally multiplexes the first signal, which is generated before the transmission timing of the second signal, at the transmission timing of the second signal.

[0193] In one embodiment of the present disclosure, the first terminal type indicates an Internet of Things (IoT) terminal that performs satellite communication, and the second terminal type indicates a terminal that performs satellite communication in an airborne vehicle.

[0194] A communication device according to one embodiment of the present disclosure includes a receiving circuit that receives a non-orthogonal multiplexed signal, and a control circuit that removes, from the non-orthogonal multiplexed signal, one of a first signal with a first reception power corresponding to a first terminal type and a second signal with a second reception power corresponding to a second terminal type.

[0195] In one embodiment of the present disclosure, the control circuit removes the second signal having the second received power higher than the first received power.

[0196] In one embodiment of the present disclosure, the control circuit removes the first signal when the communication device is a terminal of the second terminal type.

[0197] In a communication method according to one embodiment of the present disclosure, a communication device, in non-orthogonal multiplexing, assigns a first transmission power to a first signal corresponding to a first terminal type and assigns a second transmission power to a second signal corresponding to a second terminal type, and transmits the non-orthogonally multiplexed first signal and second signal.

[0198] In a communication method according to one embodiment of the present disclosure, a communication device receives a non-orthogonal multiplexed signal and removes from the non-orthogonal multiplexed signal one of a first signal with a first reception power corresponding to a first terminal type and a second signal with a second transmission power corresponding to a second terminal type.

[0199] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2019-236799, filed on December 26, 2019, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0200] One aspect of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0201] 100 base stations 101, 103, 205, 305 Data generation section 102, 104, 206, 306 Data transmission processing unit 105 NOMA Multiplexing Section 106 Control information generation unit 107 Control information transmission processing unit 108,207,307 Radio transmitter 109,201,301 Antenna 110,202,302 Radio receiver 111 Receiving processing unit 200,300 devices 203, 303 Control information receiving processing unit 204,304 Data receiving processing unit

Claims

1. a control circuit that allocates a first transmission power to a plurality of first signals corresponding to a first terminal type and allocates a second transmission power lower than the first transmission power to a second signal corresponding to a second terminal type in non-orthogonal multiplexing; a transmission circuit for transmitting the non-orthogonally multiplexed first signal and second signal; Equipped with the plurality of first signals are orthogonally multiplexed; The control circuit controls collective encoding and modulation of concatenated data obtained by concatenating the plurality of orthogonally multiplexed first signals, and adds a cyclic redundancy check (CRC) bit to the concatenated data. Communication equipment.

2. the control circuit non-orthogonally multiplexes the first signal, which is generated before the transmission timing of the second signal, at the transmission timing of the second signal. The communication device according to claim 1 .

3. the first terminal type indicates an Internet of Things (IoT) terminal that performs satellite communication, The second terminal type indicates a terminal that performs satellite communication in an airborne vehicle. The communication device according to claim 1 .

4. a receiving circuit for receiving a non-orthogonal multiplexed signal; a control circuit that performs a collective removal process on a plurality of first signals of a first reception power corresponding to a first terminal type in the non-orthogonal multiple signal, and extracts a second signal of a second reception power corresponding to a second terminal type that is lower than the first reception power; Equipped with the plurality of first signals are orthogonally multiplexed; collectively encoding and modulating concatenated data obtained by concatenating the plurality of orthogonally multiplexed first signals, and adding a cyclic redundancy check (CRC) bit to the concatenated data; Communication equipment.

5. the first terminal type indicates an Internet of Things (IoT) terminal that performs satellite communication, The second terminal type indicates a terminal that performs satellite communication in an aircraft. The communication device according to claim 4.

6. The communication device In non-orthogonal multiplexing, a first transmission power is assigned to a plurality of first signals corresponding to a first terminal type, and a second transmission power lower than the first transmission power is assigned to a second signal corresponding to a second terminal type; transmitting the non-orthogonally multiplexed first signal and second signal; the plurality of first signals are orthogonally multiplexed; A collective encoding and modulation of concatenated data obtained by concatenating the plurality of orthogonally multiplexed first signals is controlled, and a cyclic redundancy check (CRC) bit is added to the concatenated data. Communication method.

7. The communication device receiving a non-orthogonal multiplexed signal; performing a collective removal process on a plurality of first signals having a first reception power corresponding to a first terminal type in the non-orthogonal multiple signal, and extracting a second signal having a second transmission power lower than the first reception power corresponding to a second terminal type; the plurality of first signals are orthogonally multiplexed; collectively encoding and modulating concatenated data obtained by concatenating the plurality of orthogonally multiplexed first signals, and adding a cyclic redundancy check (CRC) bit to the concatenated data; Communication method.

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