Patent Application
20240422750
The present disclosure relates to a communication control method and a control terminal used in a mobile communication system.
In recent years, a mobile communication system of the fifth generation (5G) has been attracting attention. New Radio (NR), which is a radio access technology of the 5G system, is capable of wide-band transmission via a high frequency band as opposed to Long Term Evolution (LTE), which is a fourth-generation radio access technology.
Since radio signals (radio waves) in the high frequency band such as a millimeter wave band or a terahertz wave band have high rectilinearity, reduction of coverage of a base station is a problem. In order to solve such a problem, a repeater apparatus is attracting attention that is a kind of relay apparatuses relaying radio signals between a base station and a user equipment, and can be controlled from a network (see, for example, Non-Patent Document 1). Such a repeater apparatus can extend the coverage of the base station while suppressing occurrence of interference by, for example, amplifying a radio signal received from the base station and transmitting the radio wave through directional transmission.
In a first aspect, a communication control method is a method for controlling a relay apparatus configured to relay a radio signal between a base station and a user equipment in a time division duplex system. The communication control method includes a step of performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment, a step of performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation, and a step of performing, in a time period between a downlink time period during which the downlink relay operation is performed and an uplink time period during which the uplink relay operation is performed, operation switching between the downlink relay operation and the uplink relay operation at a predetermined timing within the time period.
In a second aspect, a control terminal includes a controller. The controller causes a relay apparatus configured to relay a radio signal between a base station and a user equipment in a time division duplex system to execute processing of performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment, processing of performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation, and processing of performing, in the time period between a downlink time period during which the downlink relay operation is performed and an uplink time period during which the uplink relay operation is performed, operation switching between the downlink relay operation and the uplink relay operation at a predetermined timing within the time period.
When a relay apparatus such as a repeater apparatus is controlled from a network, a control technique for specifically controlling the relay apparatus has not yet been established, and efficient coverage extension is currently difficult to perform using the relay apparatus.
Accordingly, the present disclosure provides appropriate control to control a relay apparatus that relays radio signals between a base station and a user equipment.
A mobile communication system according to an embodiment is described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference signs.
The mobile communication system 1 includes a User Equipment (UE) 100, a 5G radio access network (Next Generation Radio Access Network (NG-RAN)) 10, and a 5G Core Network (5GC) 20. The NG-RAN 10 may be hereinafter simply referred to as a RAN 10. The 5GC 20 may be simply referred to as a core network (CN) 20.
The UE 100 is a mobile wireless communication apparatus. The UE 100 may be any apparatus as long as the UE 100 is used by a user. Examples of the UE 100 include a mobile phone terminal (including a smartphone), a tablet terminal, a notebook PC, a communication module (including a communication card or a chipset), a sensor or an apparatus provided on a sensor, a vehicle or an apparatus provided on a vehicle (Vehicle UE), and a flying object or an apparatus provided on a flying object (Aerial UE).
The NG-RAN 10 includes base stations (referred to as “gNBs” in the 5G system) 200. The gNBs 200 are interconnected via an Xn interface which is an inter-base station interface. Each gNB 200 manages one or more cells. The gNB 200 performs wireless communication with the UE 100 that has established a connection to the cell of the gNB 200. The gNB 200 has a radio resource management (RRM) function, a function of routing user data (hereinafter simply referred to as “data”), a measurement control function for mobility control and scheduling, and the like. The “cell” is used as a term representing a minimum unit of a wireless communication area. The “cell” is also used as a term representing a function or a resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency (hereinafter simply referred to as one “frequency”).
Note that the gNB can be connected to an Evolved Packet Core (EPC) corresponding to a core network of LTE. An LTE base station can also be connected to the 5GC. The LTE base station and the gNB can be connected via an inter-base station interface.
The 5GC 20 includes an Access and Mobility Management Function (AMF) and a User Plane Function (UPF) 300. The AMF performs various types of mobility controls and the like for the UE 100. The AMF manages mobility of the UE 100 by communicating with the UE 100 by using Non-Access Stratum (NAS) signaling. The UPF controls data transfer. The AMF and UPF are connected to the gNB 200 via an NG interface which is an interface between a base station and the core network.
A radio interface protocol of the user plane includes a physical (PHY) layer, a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, and a Service Data Adaptation Protocol (SDAP) layer.
The PHY layer performs coding and decoding, modulation and demodulation, antenna mapping and demapping, and resource mapping and demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the gNB 200 via a physical channel. Note that the PHY layer of the UE 100 receives downlink control information (DCI) transmitted from the gNB 200 over a physical downlink control channel (PDCCH). Specifically, the UE 100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires successfully decoded DCI as DCI addressed to the UE 100. The DCI transmitted from the gNB 200 is appended with CRC parity bits scrambled by the RNTI.
The MAC layer performs priority control of data, retransmission processing through hybrid ARQ (HARQ: Hybrid Automatic Repeat reQuest), a random access procedure, and the like. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the gNB 200 via a transport channel. The MAC layer of the gNB 200 includes a scheduler. The scheduler decides transport formats (transport block sizes, Modulation and Coding Schemes (MCSs)) in the uplink and the downlink and resource blocks to be allocated to the UE 100.
The RLC layer transmits data to the RLC layer on the reception side by using functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via a logical channel.
The PDCP layer performs header compression/decompression, encryption/decryption, and the like.
The SDAP layer performs mapping between an IP flow as the unit of Quality of Service (QOS) control performed by a core network and a radio bearer as the unit of QoS control performed by an Access Stratum (AS). Note that, when the RAN is connected to the EPC, the SDAP need not be provided.
The protocol stack of the radio interface of the control plane includes a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer instead of the SDAP layer illustrated in
RRC signaling for various configurations is transmitted between the RRC layer of the UE 100 and the RRC layer of the gNB 200. The RRC layer controls a logical channel, a transport channel, and a physical channel according to establishment, re-establishment, and release of a radio bearer. When a connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200 is present, the UE 100 is in an RRC connected state. When no connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200 is present, the UE 100 is in an RRC idle state. When the connection between the RRC of the UE 100 and the RRC of the gNB 200 is suspended, the UE 100 is in an RRC inactive state.
The NAS layer which is positioned higher than the RRC layer performs session management, mobility management, and the like. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of an AMF 300A. Note that the UE 100 includes an application layer other than the protocol of the radio interface. A layer lower than the NAS layer is referred to as an AS layer.
Application scenarios for an NCR apparatus are described that is the relay apparatus according to the embodiment.
The 5G/NR is capable of wide-band transmission via a high frequency band compared to the 4G/LTE. Since radio signals in the high frequency band such as a millimeter wave band or a terahertz wave band have high rectilinearity, a problem is reduction of coverage of the gNB 200. In
In the embodiment, a repeater apparatus (500A) is a type of a relay apparatus relaying radio signals between the gNB 200 and the UE 100A, and can be controlled from the network. The repeater apparatus (500A) is introduced into the mobile communication system 1. Hereinafter, such a repeater apparatus is referred to as a Network-Controlled Repeater (NCR) apparatus. Such a repeater apparatus may be referred to as a smart repeater apparatus.
For example, the NCR apparatus 500A amplifies a radio signal received from the gNB 200 and transmits the radio signal through directional transmission. To be specific, the NCR apparatus 500A receives a radio signal transmitted by the gNB 200 through beamforming. The NCR apparatus 500A amplifies the received radio signal and transmits the amplified radio signal through the directional transmission. Here, the NCR apparatus 500A may transmit a radio signal with a fixed directivity. The NCR apparatus 500A may transmit a radio signal with a variable (adaptive) directional beam. This can efficiently extend the coverage of the gNB 200. Although in the embodiment, it is assumed that the NCR apparatus 500A is applied to downlink communication from the gNB 200 to the UE 100A, the NCR apparatus 500A can also be applied to uplink communication from the UE 100A to the gNB 200.
As illustrated in
The NCR-UE 100B may be configured separately from the NCR apparatus 500A. For example, the NCR-UE 100B may be located near the NCR apparatus 500A and may be electrically connected to the NCR apparatus 500A. The NCR-UE 100B may be connected to the NCR apparatus 500A by wire or wireless. The NCR-UE 100B may be configured to be integrated with the NCR apparatus 500A. The NCR-UE 100B and the NCR apparatus 500A may be fixedly installed at a coverage edge (cell edge) of the base station 200, or on a wall surface or window of any building, for example. The NCR-UE 100B and the NCR apparatus 500A may be installed in, for example, a vehicle to be movable. One NCR-UE 100B may control a plurality of NCR apparatuses 500A.
In the example illustrated in
As illustrated in
The NCR-UE 100B includes at least one layer (entity) selected from the group consisting of PHY, MAC, RRC, and F1-Application Protocol (AP). The F1-AP is a type of a fronthaul interface. The NCR-UE 100B communicates downlink signaling and/or uplink signaling, which will be described below, with the gNB 200 through at least one selected from the group consisting of the PHY, the MAC, RRC, and the F1-AP. When the NCR-UE 100B is a type or a part of the base station, the NCR-UE 100B may communicate with the gNB 200 through an AP of Xn (Xn-AP) which is an inter-base station interface.
In the embodiment, configurations of the NCR-UE 100B (control terminal) and the NCR apparatus 500A are described.
As illustrated in
The receiver 110 performs various types of reception under control of the controller 130. The receiver 110 includes an antenna and a reception device. The reception device converts a radio signal (radio signal) received through the antenna into a baseband signal (a reception signal) and outputs the resulting signal to the controller 130. The transmitter 120 performs various types of transmission under control of the controller 130. The transmitter 120 includes an antenna and a transmission device. The transmission device converts a baseband signal (a transmission signal) output by the controller 130 into a radio signal and transmits the resulting signal through the antenna.
The controller 130 performs various types of control in the NCR-UE 100B. The controller 130 includes at least one processor and at least one memory. The memory stores a program to be executed by the processor and information to be used for processing by the processor. The processor may include a baseband processor and a Central Processing Unit (CPU). The baseband processor performs modulation and demodulation, coding and decoding, and the like of a baseband signal. The CPU executes the program stored in the memory to thereby perform various types of processing. The controller 130 performs a function of at least one layer selected from the group consisting of the PHY, the MAC, the RRC, and the F1-AP.
The interface 140 is electrically connected to the NCR apparatus 500A. The controller 130 controls the NCR apparatus 500A via the interface 140. Note that when the NCR-UE 100B is configured to be integrated with the NCR apparatus 500A, the NCR-UE 100B may not need to include the interface 140. The receiver 110 and the transmitter 120 of the NCR-UE 100B may be configured to be integrated with a wireless unit 510A of the NCR apparatus 500A.
The NCR apparatus 500A includes the wireless unit 510A and an NCR controller 520A. The wireless unit 510A includes an antenna unit 510a including a plurality of antennas, an RF circuit 510b including an amplifier, and a directivity controller 510c controlling directivity of the antenna unit 510a. The RF circuit 510b amplifies and relays (transmits) radio signals transmitted and received by the antenna unit 510a. The RF circuit 510b may convert a radio signal, which is an analog signal, into a digital signal, and may reconvert the digital signal into an analog signal after digital signal processing. The directivity controller 510c may perform analog beamforming by analog signal processing. The directivity controller 510c may perform digital beamforming by the digital signal processing. The directivity controller 510c may perform analog and digital hybrid beamforming.
The NCR controller 520A controls the wireless unit 510A in response to a control signal from the controller 130 of the NCR-UE 100B. The NCR controller 520A may include at least one processor. The NCR controller 520A may output information relating to a capability of the NCR apparatus 500A to the NCR-UE 100B. Note that when the NCR-UE 100B is configured to be integrated with the NCR apparatus 500A, the controller 130 of the NCR-UE 100B may also be configured to be integrated with the NCR controller 520A of the NCR apparatus 500A.
In the embodiment, the receiver 110 of the NCR-UE 100B receives signaling (downlink signaling) used to control the NCR apparatus 500A from the gNB 200 through wireless communication. The controller 130 of the NCR-UE 100B controls the NCR apparatus 500A based on the signaling. This enables the gNB 200 to control the NCR apparatus 500A via the NCR-UE 100B.
In the embodiment, the controller 130 of the NCR-UE 100B controls the NCR apparatus 500A. The controller 130 of the NCR-UE 100B acquires NCR capability information indicating the capability of the NCR apparatus 500A from the NCR apparatus 500A (NCR controller 520A). The transmitter 120 of the NCR-UE 100B transmits the acquired NCR capability information to the gNB 200 through wireless communication. The NCR capability information is an example of the uplink signaling from the NCR-UE 100B to the gNB 200. This enables the gNB 200 to grasp the capability of the NCR apparatus 500A.
In the embodiment, a configuration of the gNB 200 (base station) is described.
As illustrated in
The transmitter 210 performs various types of transmission under control of the controller 230. The transmitter 210 includes an antenna and a transmission device. The transmission device converts a baseband signal (a transmission signal) output by the controller 230 into a radio signal and transmits the resulting signal through the antenna. The receiver 220 performs various types of reception under control of the controller 230. The receiver 220 includes an antenna and a reception device. The reception device converts a radio signal received through the antenna into a baseband signal (a reception signal) and outputs the resulting signal to the controller 230. The transmitter 210 and the receiver 220 may be capable of beamforming using a plurality of antennas.
The controller 230 performs various types of controls for the gNB 200. The controller 230 includes at least one processor and at least one memory. The memory stores a program to be executed by the processor and information to be used for processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation and demodulation, coding and decoding, and the like of a baseband signal. The CPU executes the program stored in the memory to thereby perform various types of processing.
The backhaul communicator 240 is connected to a neighboring base station via the inter-base station interface. The backhaul communicator 240 is connected to the AMF/UPF 300 via the interface between a base station and the core network. Note that the gNB may include a Central Unit (CU) and a Distributed Unit (DU) (i.e., functions are divided), and both units may be connected via an F1 interface.
In the embodiment, the transmitter 210 of the gNB 200 transmits signaling (downlink signaling) used to control the NCR apparatus 500A to the NCR-UE 100B controlling the NCR apparatus 500A through wireless communication. This enables the gNB 200 to control the NCR apparatus 500A via the NCR-UE 100B.
In the embodiment, the receiver 220 of the gNB 200 receives the NCR capability information indicating the capability of the NCR apparatus 500A from the NCR-UE 100B controlling the NCR apparatus 500A through wireless communication. The NCR capability information is an example of the uplink signaling from the NCR-UE 100B to the gNB 200. This enables the gNB 200 to grasp the capability of the NCR apparatus 500A.
In the embodiment, operations of the mobile communication system 1 are described.
The gNB 200 (transmitter 210) transmits downlink signaling to the NCR-UE 100B. The downlink signaling may be an RRC message that is RRC layer (i.e., layer-3) signaling. The downlink signaling may be a MAC Control Element (CE) that is MAC layer (i.e., layer-2) signaling. The downlink signaling may be downlink control information (DCI) that is PHY layer (i.e., layer-1) signaling. The downlink signaling may be UE-specific signaling. The downlink signaling may be broadcast signaling. The downlink signaling may be a fronthaul message (for example, F1-AP message). When the NCR-UE 100B is a type or a part of the base station, the NCR-UE 100B may communicate with the gNB 200 through an AP of Xn (Xn-AP) which is an inter-base station interface.
For example, as illustrated in
As illustrated in
The NCR control signal may include mode control information to designate an operation mode of the NCR apparatus 500A. The mode control information may be associated with the frequency control information (center frequency). The operation mode may be any one of a mode in which the NCR apparatus 500A performs non-directional transmission and/or reception, a mode in which the NCR apparatus 500A performs fixed-directional transmission and/or reception, a mode in which the NCR apparatus 500A performs transmission and/or reception with a variable directional beam, and a mode in which the NCR apparatus 500A performs Multiple Input Multiple Output (MIMO) relay transmission. The operation mode may be either a beamforming mode (that is, a mode in which improvement of a desired wave is emphasized) and a null steering mode (that is, a mode in which suppression of an interference wave is emphasized). When the NCR control signal received from the gNB 200 includes the mode control information, the NCR-UE 100B (controller 130) controls the NCR apparatus 500A such that the NCR apparatus 500A operates in the operation mode indicated by the mode control information (step S2). Since the NCR control signal includes the mode control information, the gNB 200 can designate the operation mode of the NCR apparatus 500A via the NCR-UE 100B.
Here, the mode in which the NCR apparatus 500A performs non-directional transmission and/or reception is a mode in which the NCR apparatus 500A performs relay in all directions and may be referred to as an omnidirectional mode.
The mode in which the NCR apparatus 500A performs fixed-directional transmission and/or reception may be a directivity mode realized by one directional antenna. The mode for performing the transmission and/or reception may be a beamforming mode realized by applying fixed phase and amplitude control (antenna weight control) to a plurality of antennas. Any of these modes may be designated (configured) from the gNB 200 to the NCR-UE 100B.
The mode in which the NCR apparatus 500A performs transmission and/or reception with a variable directional beam may be a mode for performing analog beamforming. The mode for performing the transmission and/or reception may be a mode for performing digital beamforming. The mode for performing the transmission and/or reception may be a mode for performing hybrid beamforming. The mode may be a mode for forming an adaptive beam specific to a UE 100A. Any of these modes may be designated (configured) from the gNB 200 to the NCR-UE 100B.
Note that in the operation mode in which beamforming is performed, beam control information described below may be provided from the gNB 200 to the NCR-UE 100B.
The mode in which the NCR apparatus 500A performs MIMO relay transmission may be a mode for performing Single-User (SU) spatial multiplexing. The mode for performing the MIMO relay transmission may be a mode for performing Multi-User (MU) spatial multiplexing. The mode for performing the MIMO relay transmission may be a mode for performing transmission diversity. Any of these modes may be designated (configured) from the gNB 200 to the NCR-UE 100B.
The operation mode may include a mode in which relay transmission by the NCR apparatus 500A is turned on (activated) and a mode in which relay transmission by the NCR apparatus 500A is turned off (deactivated). Any of these modes may be designated (configured) from the gNB 200 to the NCR-UE 100B in the NCR control signal.
The NCR control signal may include the beam control information to designate a transmission direction, a transmission weight, or a beam pattern for the NCR apparatus 500A to perform directional transmission. The beam control information may be associated with the frequency control information (center frequency). The beam control information may include a Precoding Matrix Indicator (PMI). When the NCR control signal received from the gNB 200 includes the beam control information, the NCR-UE 100B (controller 130) controls the NCR apparatus 500A such that the NCR apparatus 500A forms a transmission directivity (beam) indicated by the beam control information (step S2). Since the NCR control signal includes the beam control information, the gNB 200 can control the transmission directivity of the NCR apparatus 500A via the NCR-UE 100B.
The NCR control signal may include output control information to designate a degree for the NCR apparatus 500A to amplify a radio signal (amplification gain) or transmission power. The output control information may be information indicating a difference value (that is, a relative value) between the current amplification gain or transmission power and the target amplification gain or transmission power. When the NCR control signal received from the gNB 200 includes the output control information, NCR-UE 100B (controller 130) controls the NCR apparatus 500A such that the NCR apparatus 500A changes the amplification gain or transmission power to that indicated by the output control information (step S2). The output control information may be associated with the frequency control information (center frequency). The output control information may be information to designate any one of an amplification gain, a beamforming gain, and an antenna gain of the NCR apparatus 500A. The output control information may be information to designate the transmission power of the NCR apparatus 500A.
When one NCR-UE 100B controls a plurality of NCR apparatuses 500, the gNB 200 (transmitter 210) may transmit the NCR control signal for respective one of the NCR apparatuses 500A to the NCR-UE 100B. In this case, the NCR control signal may include an identifier of the corresponding NCR apparatus 500A (NCR identifier). The NCR-UE 100B (controller 130) controlling the plurality of NCR apparatuses 500 determines the NCR apparatus 500A to which the NCR control signal is applied, based on the NCR identifier included in the NCR control signal received from the gNB 200. Note that the NCR identifier may be transmitted together with the NCR control signal from the NCR-UE 100B to the gNB 200 even when the NCR-UE 100B controls only one NCR apparatus 500A.
As described above, the NCR-UE 100B (controller 130) controls the NCR apparatus 500A based on the NCR control signal from the gNB 200. This enables the gNB 200 to control the NCR apparatus 500A via the NCR-UE 100B.
The NCR-UE 100B (transmitter 210) transmits uplink signaling to the gNB 200. The uplink signaling may be an RRC message that is RRC layer signaling. The uplink signaling may be a MAC CE that is MAC layer signaling. The uplink signaling may be uplink control information (UCI) that is PHY layer signaling. The uplink signaling may be a fronthaul message (for example, F1-AP message). The uplink signaling may be an inter-base station message (for example, Xn-AP message). The uplink signaling may be a message of a layer (for example, an NCR application) higher than the RRC layer. The uplink signaling may be transmitting a message of a layer higher than the RRC layer encapsulated with a message of a layer equal to or lower than the RRC layer. Note that the gNB 200 (transmitter 210) may transmit a response message with respect to the uplink signaling from the NCR-UE 100B in the downlink, and the NCR-UE 100B (receiver 110) may receive the response message.
For example, the NCR-UE 100B (transmitter 120) having established a wireless connection to the gNB 200 transmits the NCR capability information indicating the capability of the NCR apparatus 500A to the gNB 200 through wireless communication (step S5). The NCR-UE 100B (transmitter 120) may include the NCR capability information in a UE Capability message or a UE Assistant Information message that is a type of the RRC message to transmit to the gNB 200. The NCR-UE 100B (transmitter 120) may transmit the NCR capability information (NCR capability information and/or operation state information) to the gNB 200 in response to a request or inquiry from the gNB 200.
As illustrated in
The NCR capability information may include mode capability information relating to the operation modes or switching between the operation modes that can be supported by the NCR apparatus 500A. The operation mode may be, as described above, at least any one selected from the group consisting of a mode in which the NCR apparatus 500A performs non-directional transmission and/or reception, a mode in which the NCR apparatus 500A performs fixed-directional transmission and/or reception, a mode in which the NCR apparatus 500A performs transmission and/or reception with a variable directional beam, and a mode in which the NCR apparatus 500A performs Multiple Input Multiple Output (MIMO) relay transmission. The operation mode may be either a beamforming mode (that is, a mode in which improvement of a desired wave is emphasized) and a null steering mode (that is, a mode in which suppression of an interference wave is emphasized). The mode capability information may be information indicating which operation mode among these operation modes the NCR apparatus 500A can support. The mode capability information may be information indicating between which operation modes among these operation modes the mode switching is possible. When the NCR capability information received from the NCR-UE 100B includes the mode capability information, the gNB 200 (controller 230) can grasp the operation modes and mode switching supported by the NCR apparatus 500A, based on the mode capability information. The gNB 200 (controller 230) may configure the operation mode of the NCR apparatus 500A within a range of the grasped operation modes and mode switching.
The NCR capability information may include the beam capability information indicating a beam variable range, a beam variable resolution, or the number of variable patterns when the NCR apparatus 500A performs transmission and/or reception with a variable directional beam. The beam capability information may be, for example, information indicating a variable range of a beam angle with respect to the horizontal direction or the vertical direction (for example, control of 30° to 90° is possible). The beam capability information may be information indicating an absolute angle. The beam capability information may be represented by a direction and/or an elevation angle at which a beam is directed. The beam capability information may be information indicating an angular change for each variable step (for example, horizontal 5°/step, vertical 10°/step). The beam capability information may be information indicating the number of variable steps (for example, horizontal 10 steps and vertical 20 steps). The beam capability information may be information indicating the number of variable patterns of a beam in the NCR apparatus 500A (for example, a total of 10 patterns of beam patterns 1 to 10). When the NCR capability information received from the NCR-UE 100B includes the beam capability information, the gNB 200 (controller 230) can grasp the beam angle change or beam patterns that can be supported by the NCR apparatus 500A, based on the beam capability information. The gNB 200 (controller 230) may configure a beam of the NCR apparatus 500A within a range of the grasped beam angular change or beam patterns. These pieces of beam capability information may be null capability information. For the null capability information, a null control capability when null steering is performed is indicated.
The NCR capability information may include control delay information indicating a control delay time in the NCR apparatus 500A. For example, the control delay information is information indicating a delay time (for example, 1 ms, 10 ms . . . ) from a timing at which the UE 100 receives an NCR control signal or a timing at which the UE 100 transmits configuration completion for the NCR control signal to the gNB 200 until the UE 100 completes control (change of the operation mode or change of the beam) according to the NCR control signal. When the NCR capability information received from the NCR-UE 100B includes the control delay information, the gNB 200 (controller 230) can grasp the control delay time in the NCR apparatus 500A, based on the control delay information.
The NCR capability information may include amplification characteristic information relating to radio signal amplification characteristics or output power characteristics in the NCR apparatus 500A. The amplification characteristic information may be information indicating an amplifier gain (dB), a beamforming gain (dB), and an antenna gain (dBi) of the NCR apparatus 500A. The amplification characteristic information may be information indicating an amplification variable range (for example, 0 dB to 60 dB) in the NCR apparatus 500A. The amplification characteristic information may be information indicating the number of steps (for example, 10 steps) of the amplification degrees that can be changed by the NCR apparatus 500A or the amplification degree for each variable step (for example, 10 dB/step). The amplification characteristic information may be information indicating an output power variable range (for example, 0 dBm to 30 dBm) of the NCR apparatus 500A. The amplification characteristic information may be information indicating the number of steps (for example, 10 steps) of the output power that can be changed by the NCR apparatus 500A or the output power for each variable step (for example, 10 dBm/step).
The NCR capability information may include position information indicating an installation location of the NCR apparatus 500A. The position information may include any one or more of latitude, longitude, and altitude. The position information may include information indicating a distance and/or an installation angle of the NCR apparatus 500A with respect to the gNB 200. The installation angle may be a relative angle with respect to the gNB 200, or a relative angle with respect to, for example, north, vertical, or horizontal. The installation location may be position information of a place where the antenna unit 510a of the NCR apparatus 500A is installed.
The NCR capability information may include antenna information indicating the number of antennas included in the NCR apparatus 500A. The antenna information may be information indicating the number of antenna ports included in the NCR apparatus 500A. The antenna information may be information indicating a degree of freedom of the directivity control (beam or null formation). The degree of freedom indicates how many beams can be formed (controlled) and is usually “(the number of antennas)−1”. For example, in the case of two antennas, the degree of freedom is one. In the case of two antennas, an 8-shaped beam pattern is formed, but the directivity control can be performed only in one direction, so that the degree of freedom is one.
When the NCR-UE 100B controls a plurality of NCR apparatuses 500, the NCR-UE 100B (transmitter 120) may transmit the NCR capability information for each NCR apparatus 500A to the gNB 200. In this case, the NCR capability information may include an identifier of the corresponding NCR apparatus 500A (NCR identifier). When the NCR-UE 100B controls a plurality of NCR apparatuses 500, the NCR-UE 100B (transmitter 120) may transmit information indicating the respective identifiers of the plurality of NCR apparatuses 500A and/or the number of the plurality of NCR apparatuses 500A. Note that the NCR identifier may be transmitted together with the NCR capability information from the NCR-UE 100B to the gNB 200 even when the NCR-UE 100B controls only one NCR apparatus 500A.
In step S11, the NCR-UE 100B is in the RRC idle state or the RRC inactive state.
In step S12, the gNB 200 (transmitter 210) broadcasts NCR support information indicating that the gNB 200 supports the NCR-UE 100B. For example, the gNB 200 (transmitter 210) broadcasts a system information block (SIB) including the NCR support information. The NCR support information may be information indicating that the NCR-UE 100B is accessible. The gNB 200 (transmitter 210) may broadcast NCR non-support information indicating that the gNB 200 does not support the NCR-UE 100B. The NCR non-support information may be information indicating that the NCR-UE 100B is inaccessible.
The NCR-UE 100B (controller 130) having not established a wireless connection to the gNB 200 may determine that access to the gNB 200 is permitted in response to receiving the NCR support information from the gNB 200, and may perform an access operation to establish a wireless connection to the gNB 200. The NCR-UE 100B (controller 130) may regard the gNB 200 (cell) to which access is permitted as the highest priority and perform cell reselection.
On the other hand, when the gNB 200 does not broadcast the NCR support information (or when the gNB 200 broadcasts the NCR non-support information), the NCR-UE 100B (controller 130) having not established a wireless connection to the gNB 200 may determine that access (connection establishment) to the gNB 200 is not possible. This enables the NCR-UE 100B to establish a wireless connection only to the gNB 200 capable of handling the NCR-UE 100B.
Note that when the gNB 200 is congested, the gNB 200 may broadcast access restriction information to restrict an access from the UE 100. However, unlike a normal UE 100, the NCR-UE 100B can be regarded as a network-side entity. Therefore, the NCR-UE 100B may ignore the access restriction information from the gNB 200. For example, the NCR-UE 100B (controller 130), when receiving the NCR support information from the gNB 200, may perform an operation to establish a wireless connection to the gNB 200 even if the gNB 200 broadcasts the access restriction information. For example, the NCR-UE 100B (controller 130) may not need to perform (or may ignore) Unified Access Control (UAC). Alternatively, any one or both of Access Category/Access Identity (AC/AI) used in the UAC may be a special value indicating that the access is made by the NCR-UE.
In step S13, the NCR-UE 100B (controller 130) starts a random access procedure for the gNB 200. In the random access procedure, the NCR-UE 100B (transmitter 120) transmits a random access preamble (Msg1) and an RRC message (Msg3) to the gNB 200. In the random access procedure, the NCR-UE 100B (receiver 110) receives a random access response (Msg2) and an RRC message (Msg4) from the gNB 200.
In step S14, the NCR-UE 100B (transmitter 120), when establishing a wireless connection to the gNB 200, may transmit NCR-UE information indicating that the NCR-UE 100B itself is an NCR-UE to the gNB 200. For example, the NCR-UE 100B (transmitter 120), during the random access procedure with the gNB 200, includes the NCR-UE information in the message (for example, Msg1, Msg3, Msg5) for the random access procedure to transmit to the gNB 200. The gNB 200 (controller 230) can recognize that the accessing UE 100 is the NCR-UE 100B, based on the NCR-UE information received from the NCR-UE 100B, and exclude from the access restriction target (in other words, accept the access from), for example, the NCR-UE 100B.
In step S15, the NCR-UE 100B transitions from the RRC idle state or the RRC inactive state to the RRC connected state.
In step S16, the gNB 200 (transmitter 120) transmits a capability inquiry message to inquire the capability of the NCR-UE 100B to the NCR-UE 100B. The NCR-UE 100B (receiver 110) receives the capability inquiry message.
In step S17 the NCR-UE 100B (transmitter 120) transmits a capability information message including the NCR capability information described above to the gNB 200. The gNB 200 (receiver 220) receives the capability information message. The gNB 200 (controller 230) grasps the capability of the NCR apparatus 500A based on the received capability information message.
In step S18, the gNB 200 (transmitter 120) transmits the NCR control signal designating the operation state of the NCR apparatus 500A to the NCR-UE 100B. The gNB 200 (transmitter 120) may transmit, as the NCR control signal, a MAC CE that is MAC-layer (layer-2) signaling or DCI that is PHY-layer (layer-1) signaling to the NCR-UE 100B. The NCR-UE 100B (receiver 110) receives the NCR control signal.
In step S19, the NCR-UE 100B (controller 130) controls the NCR apparatus 500A, based on the NCR control signal received from the gNB 200. The NCR-UE 100B (controller 130) may control the NCR apparatus 500A by notifying the NCR apparatus 500A (NCR controller 520A) of the NCR control signal received from the gNB 200.
In step S20, the NCR-UE 100B (transmitter 120), when completing the control of (configuration change) of the NCR apparatus 500A, may transmit a completion message to the gNB 200. Here, the NCR-UE 100B (controller 130) may determine the control completion, based on a notification (feedback) from the NCR apparatus 500A (NCR controller 520A). The gNB 200 (receiver 220) receives the completion message.
Operations of the NCR-UE 100B (control terminal) and the NCR apparatus 500A (relay apparatus) when time division duplex (TDD) is applied to the mobile communication system 1 are described. Hereinafter, the downlink is denoted by DL and the uplink is denoted by UL.
Note that in NR, one subframe includes a plurality of symbols in the time domain. A unit for resource allocation is a resource block, and the resource block includes a plurality of symbols and a plurality of subcarriers in a frequency direction. The frame may have 10 ms and may include 10 subframes each of which has 1 ms. The subframe may include slots the number of which corresponds to a subcarrier spacing.
As illustrated in
After a propagation delay time from time t0 to time t1 elapses, during the DL time period from time t1 to time t4, the NCR apparatus 500A receives the DL signal from the gNB 200, amplifies the received DL signal, and transmits the amplified DL signal to the UE 100A. In this manner, during the DL time period from time t1 to time t4, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the DL relay operation. Note that the time period from time t0 to time t1 may include not only the propagation delay time but also an internal processing time (processing delay time) of the NCR apparatus 500A.
After a propagation delay time from time t1 to time t2 elapses, during the DL time period from time t2 to time t5, the UE 100A receives the DL signal from the NCR apparatus 500A.
During a UL transmission time period from time t6 to time t9, the UE 100A transmits a UL signal to the NCR apparatus 500A. Here, a transmission timing of the UL signal in the UE 100A is adjusted according to the timing advance (TA) managed by the UE 100A. The TA is a value managed by the UE 100A in order to compensate for the propagation delay time. The UE 100A transmits the UL signal at a timing advanced by a time indicated by the TA with respect to a DL timing. Note that the UE 100A may update the TA based on a TA command signaled from the gNB 200 to the UE 100A.
After a propagation delay time from time t6 to time t7 elapses, during the UL time period from time t7 to time t10, the NCR apparatus 500A receives the UL signal from the UE 100A, amplifies the received UL signal, and transmits the amplified UL signal to the gNB 200. In this manner, during the UL time period from time t7 to time t10, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the UL relay operation. Here, the NCR-UE 100B may adjust the transmission timing of the UL signal in accordance with a TA managed by the NCR-UE 100B. This TA is a value managed by the NCR-UE 100B in order to compensate for the propagation delay time. The NCR-UE 100B transmits the UL signal at a timing advanced by a time indicated by the TA with respect to a DL timing. Note that the NCR-UE 100B may update the TA based on a TA command signaled from the gNB 200 to the NCR-UE 100B.
After a propagation delay time from time t7 to time t8 elapses, during the UL time period from time t8 to time t11, the gNB 200 receives the UL signal from the NCR apparatus 500A. Note that the time period from time t7 to time t8 may include not only the propagation delay time but also an internal processing time (processing delay time) of the NCR apparatus 500A.
During the DL time period from time t11 to time t14, the gNB 200 transmits a DL signal to the NCR apparatus 500A.
After a propagation delay time from time t11 to time t12 elapses, during the DL time period from time t12 to time t15, the NCR apparatus 500A receives the DL signal from the gNB 200, amplifies the received DL signal, and transmits the amplified DL signal to the UE 100A. In this manner, during the DL time period from time t12 to time t15, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the DL relay operation.
After a propagation delay time from time t12 to time t13 elapses, during the DL time period from time t13 to time t16, the UE 100A receives the DL signal from the NCR apparatus 500A. Note that the time period from time t12 to time t13 may include not only the propagation delay time but also an internal processing time (hardware processing delay time) of the NCR apparatus 500A.
As described above, the NCR apparatus 500A relaying the radio signals between the gNB 200 and the UE 100A in the TDD system performs alternately the DL relay operation and the UL relay operation. In the embodiment, the NCR-UE 100B controls the NCR-UE 100B such that, in a time period between the DL time period during which the DL relay operation is performed and the UL time period during which the UL relay operation is performed, the NCR-UE 100B performs the operation switching between the DL relay operation and the UL relay operation at a predetermined timing within the time period. This enables the appropriate switching between the DL relay operation and the UL relay operation.
Here, in consideration of a control delay (for example, a hardware processing delay of the NCR apparatus 500A) when the NCR-UE 100B controls the NCR apparatus 500A, the NCR-UE 100B preferably performs the control of the operation switching between the DL relay operation and the UL relay operation before a last timing (last symbol) within the time period between the DL time period and the UL time period.
In consideration of the presence of delayed waves caused by multi-path and the like, the NCR-UE 100B preferably performs the control of the operation switching between the DL relay operation and the UL relay operation after an initial timing (initial symbol) within the time period between the DL time period and the UL time period. This enables the NCR apparatus 500A to also relay the delayed wave.
Thus, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching between DL relay operation and UL relay operation near an intermediate point within the time period between the DL time period and the UL time period. This makes it possible to appropriately control the NCR-apparatus 500A that relays the radio signal between the gNB 200 and the UE 100A.
First, an example of the operation switching from the UL relay operation to the DL relay operation is described.
The NCR-UE 100B manages the TA for adjusting the transmission timing of the UL signal from the NCR apparatus 500A to the gNB 200. In this example of the operation switching, the predetermined timing at which the control of the operation switching is performed from the UL relay operation to the DL relay operation is a timing at which a time indicated by a value obtained by dividing the TA by n (n≥2) elapses from the end timing of the UL time period. Here, it is assumed that n=2, but n=3 may be set, for example. The value obtained by division refers to the division result. However, when the division result includes a fraction after the decimal point, for example, the fraction after the decimal point may be truncated or rounded off.
The example of the operation switching from the UL relay operation to the DL relay operation is described using the time period from time t10 to time t12 illustrated in
The NCR-UE 100B checks the TA managed by the NCR-UE 100B itself and calculates “TA/2”. The NCR-UE 100B then controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching from the UL relay operation to the DL relay operation at a timing (i.e., time t11) at which a time corresponding to “TA/2” elapses from time t10.
By such a control of the operation switching, the NCR apparatus 500A performs the operation switching from the UL relay operation to the DL relay operation before time t12 at which the DL time period starts. As a result, during the DL time period from time t12 to time t15, the NCR apparatus 500A receives a DL signal from the gNB 200, amplifies the received DL signal, and transmits the amplified DL signal to the UE 100A (i.e., the DL relay operation).
Operation switching patterns 1 to 3 are described as the examples of the operation switching from the DL relay operation to the UL relay operation.
The operation switching pattern 1 is a switching pattern using the TA as in the example of the operation switching from the UL relay operation to the DL relay operation described above. On the other hand, the operation switching patterns 2 and 3 are switching patterns on the assumption that a flexible time period (Sp) available for switching from the DL time period to the UL time period is provided.
The example of the operation switching from the DL relay operation to the UL relay operation is described using the time period from time t4 to time t7 illustrated in
The NCR-UE 100B checks the TA managed by the NCR-UE 100B itself and calculates “TA/2”. The NCR-UE 100B then controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching from the DL relay operation to the UL relay operation at a timing (i.e., time t5) at which a time corresponding to “TA/2” elapses from time t4.
By such a control of the operation switching, the NCR apparatus 500A performs the operation switching from the DL relay operation to the UL relay operation before time t12 at which the UL time period starts. As a result, during the UL time period from time t7 to time t10, the NCR apparatus 500A receives a UL signal from the UE 100, amplifies the received UL signal, and transmits the amplified UL signal to the gNB 200 (i.e., the UL relay operation).
In
In this operation switching pattern 2, the predetermined timing at which the control of the operation switching from the DL relay operation to the UL relay operation is performed is a timing at an intermediate point (from another viewpoint, a symbol at the intermediate point) within the time period (specifically, the flexible time period) between the DL time period and the UL time period. In the example of
By such a control of the operation switching, the NCR apparatus 500A performs the operation switching from the DL relay operation to the UL relay operation before the symbol number “18” at which the UL time period starts. As a result, during the UL time period of the symbol numbers “18” to “27”, the NCR apparatus 500A receives a UL signal from the UE 100, amplifies the received UL signal, and transmits the amplified UL signal to the gNB 200 (i.e., the UL relay operation).
Note that when the number of symbols within the flexible time period is an odd number, the timing at the intermediate point (symbol at the intermediate point) is easy to derive. On the other hand, when the number of symbols within the flexible time period is an even number, the timing at the intermediate point (symbol at the intermediate point) may be derived as follows. For example, when the number of symbols within the flexible time period is four, the NCR-UE 100B may decide the second symbol within the flexible time period as the timing at the intermediate point (symbol at the intermediate point) or may decide the third symbol within the flexible time period as the timing at the intermediate point (symbol at the intermediate point).
The operation switching pattern 2 described above assumes that the NCR-UE 100B decides the predetermined timing in accordance with a predetermined rule. On the other hand, in the operation switching pattern 3, the predetermined timing is a designated timing designated by the gNB 200 within the time period between the DL time period and the UL time period. Specifically, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching from the UL relay operation to the DL relay operation at the designated timing designated by the gNB 200.
For example, as illustrated in
In step S102, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching from the DL relay operation to the UL relay operation in the symbol corresponding to the symbol number indicated by the received designated timing information.
As illustrated in
In step S102, the NCR-UE 100B controls the NCR apparatus 500A such that the NCR apparatus 500A performs the operation switching from the DL relay operation to the UL relay operation at a timing (symbol) at which the NCR-UE 100B receives the switching indication DCI from the gNB 200.
The embodiment described above describes the example in which the relay apparatus relaying the radio signals between the gNB 200 and the UE 100 (UE 100A) is the repeater apparatus (NCR apparatus 500A) that amplifies and transfers the received radio signals. However, the relay apparatus relaying the radio signals between the gNB 200 and the UE 100 (UE 100A) may be a Reconfigurable Intelligent Surface (RIS) apparatus that changes a propagation direction of an incident radio wave (radio signal) by reflection or refraction. The “NCR” in the above-described embodiments may be read as the “RIS”.
An RIS apparatus 500B illustrated in
The RIS apparatus 500B illustrated in
As illustrated in
The RIS-UE 100C may be configured separately from the RIS apparatus 500B. For example, the RIS-UE 100C may be located near the RIS apparatus 500B and may be electrically connected to the RIS apparatus 500B. The RIS-UE 100C may be connected to the RIS apparatus 500B by wire or wireless. The RIS-UE 100C may be configured integrally with the RIS apparatus 500B. The RIS-UE 100C and the RIS apparatus 500B may be fixedly installed on a wall surface or a window, for example. The RIS-UE 100C and the RIS apparatus 500B may be installed in, for example, a vehicle to be movable. One RIS-UE 100C may control a plurality of RIS apparatuses 500B.
As illustrated in
The RIS apparatus 500B includes a RIS 510B and a RIS controller 520. The RIS 510B is a metasurface configured using metamaterials. For example, the RIS 510B is configured by arranging very small structures in an array form with respect to a wavelength of a radio wave, in which a direction and beam shape of a reflected wave can be arbitrarily designed by forming the structures in different shapes depending on an arrangement location. The RIS 510B may be a transparent dynamic metasurface. The RIS 510B may be configured by stacking a transparent glass substrate on a metasurface substrate on which a large number of small structures are regularly arranged and which is made transparent, and may be capable of dynamically controlling three patterns of a mode of transmitting an incident radio wave, a mode of transmitting a part of a radio wave and reflecting a part thereof, and a mode of reflecting all radio waves by minutely moving the stacked glass substrate.
The RIS controller 520B controls the RIS 510B in response to a RIS control signal from the controller 130 in the RIS-UE 100C. The RIS controller 520B may include at least one processor and at least one actuator. The processor interprets a RIS control signal from the controller 130 in the RIS-UE 100C to drive the actuator in response to the RIS control signal. Note that when the RIS-UE 100C and the RIS apparatus 500B are integrally configured, the controller 130 in the RIS-UE 100C and the RIS controller 520B in the RIS apparatus 500B may also be integrally configured.
In the above description, the frequency control information may include a cell ID identifying a cell and/or a BWP ID identifying a bandwidth part (BWP). The BWP is a part of a frequency band of a cell.
The operation flows described above can be separately and independently implemented, and also be implemented in combination of two or more of the operation flows. For example, some steps of one operation flow may be added to another operation flow or some steps of one operation flow may be replaced with some steps of another operation flow. In each flow, all steps may not be necessarily performed, and only some of the steps may be performed.
In the embodiment described above, an example in which the base station is an NR base station (i.e., a gNB) is described; however, the base station may be an LTE base station (i.e., an eNB). The base station may be a relay node such as an Integrated Access and Backhaul (IAB) node. The base station may be a Distributed Unit (DU) of the IAB node.
A program causing a computer to execute each of the processes performed by the UE 100 (NCR-UE 100B, RIS-UE 100C) or the gNB 200 may be provided. The program may be recorded in a computer readable medium. Use of the computer readable medium enables the program to be installed on a computer. Here, the computer readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Circuits for executing processing performed by the UE 100 or the gNB 200 may be integrated, and at least a part of the UE 100 or the gNB 200 may be implemented as a semiconductor integrated circuit (chipset, system on a chip (SoC)).
The phrases “based on” and “depending on” used in the present disclosure do not mean “based only on” and “only depending on,” unless specifically stated otherwise. The phrase “based on” means both “based only on” and “based at least in part on”. The phrase “depending on” means both “only depending on” and “at least partially depending on”. The terms “include”, “comprise” and variations thereof do not mean “include only items stated” but instead mean “may include only items stated” or “may include not only the items stated but also other items”. The term “or” used in the present disclosure is not intended to be “exclusive or”. Any references to elements using designations such as “first” and “second” as used in the present disclosure do not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element needs to precede the second element in some manner. For example, when the English articles such as “a,” “an,” and “the” are added in the present disclosure through translation, these articles include the plural unless clearly indicated otherwise in context.
Embodiments have been described above in detail with reference to the drawings, but specific configurations are not limited to those described above, and various design variation can be made without departing from the gist of the present disclosure.
Features relating to the embodiments described above are described below as supplements.
A communication control method for controlling a relay apparatus configured to relay a radio signal between a base station and a user equipment in a time division duplex system, the communication control method including:
The communication control method according to (1) above, wherein
The communication control method according to (1) or (2) above, further including:
The communication control method according to any one of (1) to (3) above, further including:
The communication control method according to any one of (1) to (4) above, wherein a value of n is 2.
The communication control method according to any one of (1) to (5) above, wherein
The communication control method according to any one of (1) to (6) above, wherein
The communication control method according to any one of (1) to (7) above, further including:
The communication control method according to any one of (1) to (8) above, further including:
The communication control method according to any one of (1) to (9) above, wherein
The communication control method according to any one of (1) to (10) above, wherein
A control terminal including:
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-030104 | Feb 2022 | JP | national |
The present application is a continuation based on PCT Application No. PCT/JP2023/006832, filed on Feb. 24, 2023, which claims the benefit of Japanese Patent Application No. 2022-030104 filed on Feb. 28, 2022. The content of which is incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/006832 | Feb 2023 | WO |
| Child | 18816332 | US |
