User Equipment and Scheduling Node

Abstract

A UE, a scheduling node, and methods for the UE and the scheduling node are provided, the UE comprising: a circuit for monitoring, in operation, a first time or frequency resource for a first PDCCH (physical downlink control channel) in a first beam; and a transceiver for receiving, in operation, a signal for initiating a switch from the first beam to a second beam, wherein, at a timing of switching to the second beam, the circuit for switching, in operation, to the second time or frequency resource to be monitored based on the signal and a notification of a second time or frequency resource for a second PDCCH in the second beam, the first PDCCH and the second PDCCH being specific to the UE or a respective group of UEs including the UE.

Description

[Technical field]

[0001] TECHNICAL FIELD The present disclosure relates to transmitting and receiving signals in a communication system, and more particularly to methods and communication devices for such transmission and reception. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP®) is developing technical specifications for next-generation cellular technology, also known as the fifth generation (5G), which will operate in the frequency range up to 100 GHz and will include New Radio (NR) radio access technology (RAT). NR is the successor to technologies such as Long Term Evolution (LTE) and LTE Advanced (LTE-A).

[0003] In systems such as LTE, LTE-A, and NR, further improvements and options may facilitate the efficient operation of the communication systems and certain equipment associated with the systems. Summary of the Invention

[0004] One non-limiting exemplary embodiment facilitates efficient switching of time and frequency resources for downlink control information when changing serving beams.

[0005] In one embodiment, a user equipment (UE) is provided, comprising: a circuit for monitoring, in operation, a first time resource or frequency resource for a first PDCCH (physical downlink control channel) in a first beam; and a transceiver for receiving, in operation, a signal to initiate switching from the first beam to a second beam, wherein at the timing of switching to the second beam, the circuit, in operation, switches to the second time resource or frequency resource to be monitored based on the signal and notification of a second time resource or frequency resource for a second PDCCH in the second beam, and the first PDCCH and the second PDCCH are specific to the UE or a respective group of UEs including the UE.

[0006] These comprehensive or specific aspects may be realized as a system, 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.

[0007] 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 description of the drawings]

[0008] In the following, exemplary embodiments are explained in more detail with reference to the attached drawings. [Figure 1] FIG. 1 illustrates an example of a 3GPP NR system architecture. [Diagram 2] FIG. 1 is a schematic diagram showing the division of functions between NG-RAN and 5GC. [Diagram 3] FIG. 1 is a sequence diagram for an RRC connection setup / reconfiguration procedure. [Figure 4]FIG. 1 is a schematic diagram showing usage scenarios for enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC). [Diagram 5] FIG. 1 is a block diagram illustrating an example of a 5G system architecture for a non-roaming scenario. [Figure 6] A diagram showing the transmission of a synchronization signal block using beamforming. [Figure 7] FIG. 1 is a diagram illustrating the transmission of a group-common Physical Downlink Control Channel (PDCCH) using beamforming. [Figure 8] FIG. 2 is a block diagram illustrating a scheduling node and user equipment. [Figure 9] FIG. 2 is a block diagram showing a PDCCH resource monitoring circuit and a switching circuit of the UE. [Figure 10] 4 is a flow chart illustrating method steps of a scheduling node and user equipment communication method; [Figure 11] 4 is a flow chart illustrating method steps of a scheduling node and user equipment communication method; [Figure 12] 4 is a flow chart illustrating method steps of a user equipment communication method. [Figure 13] 4 is a flow chart illustrating method steps of a user equipment communication method. [Figure 14] 4 is a flow chart illustrating method steps of a user equipment communication method. [Figure 15] 4 is a flow chart illustrating method steps of a user equipment communication method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <5G NR system architecture and protocol stack> 3GPP is working on the next release of the fifth generation of cellular technology (also known simply as 5G), which includes the development of New Radio Access Technology (NR) that will operate 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 trial and commercial deployment of smartphones compliant with the 5G NR standard to proceed.

[0010] In particular, the overall system architecture assumes a Next Generation-Radio Access Network (NG-RAN) with gNodeBs (gNBs). The gNBs provide the UE-side termination of the user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC: Radio Resource Control) protocols of the NG radio access. The gNBs are interconnected with each other by an Xn interface. The gNBs are also connected to the Next Generation Core (NGC: Next Generation Core) by a Next Generation (NG) interface, more specifically to the Access and Mobility Management Function (AMF, e.g. a specific core entity that runs the AMF) by an NG-C interface and to the User Plane Function (UPF, e.g. a specific core entity that runs the UPF) by an NG-U interface. The NG-RAN architecture is shown in Figure 1 (see, e.g., section 4 of 3GPP TS 38.300 v15.6.0).

[0011] The NR user plane protocol stack (see, for example, section 4.4.1 of 3GPP TS 38.300) includes a PDCP (Packet Data Convergence Protocol, see section 6.4 of TS 38.300) sublayer, a RLC (Radio Link Control, see section 6.3 of TS 38.300) sublayer, and a MAC (Medium Access Control, see section 6.2 of TS 38.300) sublayer, which are terminated on the network side at the gNB. In addition, a new Access Stratum (AS) sublayer (SDAP: Service Data Adaptation Protocol) is introduced above PDCP (see, for example, sub-clause 6.5 of 3GPP TS 38.300). NR also defines a control plane protocol stack (see, for example, section 4.4.2 of TS 38.300). An overview of Layer 2 functions is described in sub-clause 6 of TS 38.300. The functions of the PDCP sublayer, the RLC sublayer, and the MAC sublayer are described in sections 6.4, 6.3, and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in sub-clause 7 of TS 38.300.

[0012] For example, the MAC layer is responsible for multiplexing logical channels and scheduling and scheduling-related functions, including various numerology processing.

[0013] The physical layer (PHY) is responsible for, for example, coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. It also maps 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 transmission of a particular transport channel, and each transport channel is mapped to a corresponding physical channel. For example, the physical channels are PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel) in the uplink, and PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel) in the downlink.

[0014] NR use cases / deployment scenarios include enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and / or massive Machine Type Communication (mMTC), which have diverse requirements for data rates, latency, and coverage. For example, eMBB is expected to support peak data rates (20Gbps downlink, 10Gbps uplink) and effective (user-experienced) data rates that are about three times higher than those offered in IMT-Advanced. Meanwhile, URLLC has more stringent requirements for ultra-low latency (user plane latency of 0.5ms for both UL and DL) and high reliability (1-10 Mbps latency within 1ms). -5) is imposed. Finally, mMTC preferably requires a high connection density (1 million devices per square kilometer in an urban environment), wide coverage in harsh environments, and an ultra-long-life battery (15 years) for low-cost devices.

[0015] Therefore, an OFDM numerology suitable for one use case (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) may not be effective for other use cases. For example, low-latency services may preferably require a shorter symbol length (and thus a larger subcarrier spacing) and / or fewer symbols per scheduling interval (in other words, TTI) than mMTC services. Furthermore, in a deployment scenario with a large channel delay spread, a longer CP length may preferably be required than in a scenario with a short delay spread. To maintain a similar CP overhead, the subcarrier spacing needs to be optimized as appropriate. In NR, multiple values of subcarrier spacing may be supported. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, ··· are currently being considered. The symbol length T u and the subcarrier spacing Δf are directly related by the formula Δf = 1 / T u Similar to the LTE system, the term "resource element" can be used to indicate the smallest resource unit composed of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0016] In the new radio system 5G-NR, for each numerology and carrier, a resource grid of subcarriers and OFDM symbols is defined for the uplink and downlink respectively. Each element in the resource grid is called a resource element and is identified based on the frequency index in the frequency domain and the symbol position in the time domain (3GPP TS38.211 v15.6.0).

[0017] <Functional Split between NG-RAN and 5GC> Figure 2 shows the functional division between NG-RAN and 5GC. The NG-RAN logical node is the gNB or ng-eNB. The 5GC includes the AMF, UPF, and SMF logical nodes.

[0018] Specifically, the gNB and ng-eNB (next generation eNB) provide the following main functions: Radio resource management functions such as radio bearer control, radio admission control, connection mobility control, dynamic resource allocation (scheduling) 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 information provided by the UE Routing of user plane data towards UPF Routing of control plane information for AMF Setting up and disconnecting a connection Scheduling and sending paging messages Scheduling and transmission of system notification information (from AMF or OAM) Measurement and measurement reporting configuration for mobility and scheduling Transport-level packet marking in the uplink Session Management Support for network slicing QoS flow management and allocation to data radio bearers Support for UEs in RRC_INACTIVE state NAS (Non-access stratum) message delivery function Radio Access Network Sharing Dual Connectivity Close cooperation between NR and E-UTRA

[0019] The Access and Mobility Management Function (AMF) provides the following main functions: Termination of Non-Access Stratum (NAS) signaling NAS signaling security · Access Stratum (AS) security control Core Network (CN) inter-node signaling for mobility between 3GPP access networks Reachability of idle mode UEs (including control and execution of paging retransmissions) ·Registration area management Support for intra-system and inter-system mobility Access authentication -Access authorization including roaming privilege checks Mobility management control (subscription and policy) Support for network slicing ·Session Management Function (SMF) selection

[0020] In addition, the User Plane Function (UPF) provides the following main functions: Anchor points for intra-RAT / inter-RAT mobility (when applicable) External PDU session points for interconnection with data networks Packet Routing and Forwarding Packet inspection and policy rule enforcement for the user plane Traffic usage reporting Uplink classifier that supports routing of traffic flows to the data network Branching point supporting multi-homed PDU sessions QoS processing for user plane, including packet filtering, gating, and UL / DL (uplink / downlink) rate enforcement · Uplink traffic verification (placement for the QoS flow of SDF) · Downlink packet buffering and downlink data notification trigger

[0021] Finally, the Session Management Function (SMF) provides the following main functions. · Session management · Allocation and management of IP addresses for UEs · Selection and control of UPF · Configuration of traffic steering in the User Plane Function (UPF) to route traffic to the appropriate destination · Enforcement of control plane policies and QoS · Notification of downlink data

[0022] <RRC connection setup and reconfiguration procedures> Figure 3 shows a part of the interaction between the UE, gNB, and AMF (5GC entity) when the UE moves from RRC_IDLE to RRC_CONNECTED in the NAS layer (see TS 38.300 v15.6.0).

[0023] RRC is a higher layer signaling (protocol) used for the configuration of the UE and the gNB. This transition specifically includes the AMF preparing UE context data (e.g., including PDU session context, security keys, UE Radio Capability, UE Security Capabilities, etc.) and sending it to the gNB with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security with the UE. This operation is performed by the gNB sending a Security Mode Command message to the UE, and the UE responding with a Security Mode Complete message to the gNB. The gNB then performs reconfiguration to set up a Signaling Radio Bearer 2 (SRB2) and a Data Radio Bearer (DRB) by sending an RRCReconfiguration message to the UE and receiving an RRCReconfigurationComplete from the UE in response thereto. In the case of a signaling-only connection, SRB2 and DRB are not configured, so the steps related to RRC reconfiguration are omitted. Finally, the gNB informs the AMF that the configuration procedure is complete in an INITIAL CONTEXT SETUP RESPONSE.

[0024] Therefore, in the present disclosure, a fifth generation core (5GC) entity (e.g., AMF, SMF, etc.) is provided, which includes a control circuit that establishes a next generation (NG) connection with a gNodeB during operation, and a transmitter that transmits an initial context setup message to the gNodeB via the NG connection during operation so that a signaling radio bearer between the gNodeB and a terminal (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling including a resource allocation configuration information element to the UE via the signaling radio bearer. Then, the UE performs uplink transmission or downlink reception based on the resource allocation configuration.

[0025] <IMT usage scenarios after 2020> Figure 4 shows some of the use cases for 5G NR. The 3rd Generation Partnership Project NR (3GPP NR) is considering three use cases that are expected to support a wide variety of services and applications with IMT-2020. The first phase of specifications for enhanced Multimedia Broadcasting (eMBB) has been completed. In addition to further expanding support for eMBB, standardization of ultra-reliable low latency (URLLC) and multiple simultaneous connections is also being considered now and in the future. Figure 4 shows examples of usage scenarios expected for IMT beyond 2020 (see, for example, Figure 2 in ITU-R M.2083).

[0026] URLLC use cases have stringent requirements for performance such as throughput, latency, and availability, and are envisioned as one of the enablers of future vertical applications such as wireless control of industrial production and manufacturing processes, remote medical surgery, power distribution automation for smart grids, and road safety. URLLC's ultra-high reliability is supported by identifying technologies that meet the requirements set by TR 38.913. For NR URLLC in Release 15, the key requirement is to target user plane latency of 0.5 ms UL (uplink) and 0.5 ms DL (downlink). The general URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a packet size of 32 bytes with a user plane latency of 1 ms.

[0027] From a physical layer perspective, there are various ways to improve reliability. Currently, possible ways to improve reliability are to define a separate CQI table for URLLC, a more compact DCI (Downlink Control Information) format, repeated transmission of PDCCH, etc. However, as NR becomes more stable (for the main requirement of NR URLLC) and more developed, the range of possible ways to achieve ultra-high reliability may expand. Specific use cases for NR URLLC in Release 15 include Augmented Reality / Virtual Reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0028] Additionally, NR URLLC targets technology enhancements for improved latency and improved reliability. Technology enhancements for improved latency include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configurable grant) uplink, slot-level repeated transmission of data channel, and pre-emption for downlink. Pre-emption means stopping a transmission that already has resources allocated and using the already allocated resources for another transmission that requires less latency or higher priority that is requested later. Thus, a transmission that was already allowed is preempted by a later transmission. Pre-emption can be applied 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 (e.g., eMBB). Technology enhancements for improved reliability include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0029] The mMTC (Massively Simultaneous Connections) use case is characterized by a very large number of connected devices, which typically transmit relatively small amounts of data that are not sensitive to latency. The devices are required to be low cost and have a very long battery life. From an NR perspective, using a very narrow bandwidth portion is one way to enable power saving and long battery life for the UE.

[0030] As mentioned above, the scope of reliability improvement in NR is expected to be broader. One of the key requirements common to all cases, and especially for URLLC and mMTC, is high or ultra-high reliability. There are several mechanisms to improve reliability, from the radio perspective and from the network perspective. In general, there are several key areas that can help improve reliability. These areas include compact control channel information, repeated transmission of data / control channels, diversity in frequency domain, time domain, and spatial domain. These areas are generally applicable to reliability improvement, regardless of the specific communication scenario.

[0031] Further use cases with more stringent requirements have been identified for NR URLLC, such as factory automation, the transportation industry, and power distribution. The more stringent requirements include high reliability (up to 10 times faster) depending on the use case. -6 level), high availability, packet size up to 256 bytes, time synchronization to the order of a few μs (can be 1 μs or a few μs depending on the frequency range and short latency of the order of 0.5-1 ms (e.g. 0.5 ms latency in the targeted user plane)).

[0032] Furthermore, in NR URLLC, several technology enhancements have been identified from the physical layer perspective. Among these are PDCCH (Physical Downlink Control Channel) enhancements for compact DCI, PDCCH repeat transmissions, and increased PDCCH monitoring. Also, Uplink Control Information (UCI) enhancements relate to enhanced Hybrid Automatic Repeat Request (HARQ) and CSI feedback enhancements. Also, PUSCH enhancements and retransmission / repeat transmission enhancements related to minislot level hopping have been identified. A "minislot" refers to a transmission time interval (TTI) that contains fewer symbols than a slot (a slot consisting of 14 symbols).

[0033] In slot - based scheduling or allocation, a slot corresponds to the timing granularity (TTI: Transmission Time Interval) of the scheduling allocation. Generally, the TTI determines the timing granularity of the scheduling allocation. One TTI is the time interval during which a given signal is mapped to the physical layer. For example, conventionally, the length of the TTI ranges from 14 symbols (slot - based scheduling) to 2 symbols (non - slot - based scheduling). Downlink (DL) and uplink (UL) transmissions are defined to be organized into frames (10 ms duration) consisting of 10 sub - frames (1 ms duration). In slot - based transmission, a sub - frame is further divided into slots, and the number of slots is defined by the numerology / sub - carrier spacing. The specified values range from 10 slots per frame (1 slot per sub - frame) when the sub - carrier spacing is 15 kHz to 80 slots per frame (8 slots per sub - frame) when the sub - carrier spacing is 120 kHz. The number of OFDM symbols per slot is 14 for the normal cyclic prefix and 12 for the extended cyclic prefix (see 3GPP TS38.211v15.3.0 Physical channels and modulation, September 2018, Sections 4.1 (general frame structure), 4.2 (Numerologies), 4.3.1 (frames and subframes), 4.3.2 (slots)). However, the time resource allocation for transmission may also be non - slot - based. Specifically, the TTI in non - slot - based allocation may correspond to a mini - slot instead of a slot. That is, one or more mini - slots may be allocated for the required transmission of data / control signaling. In non - slot - based allocation, the minimum length of the TTI may be, for example, 1 or 2 OFDM symbols.

[0034] <QoS control> The 5G Quality of Service (QoS) model is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, QoS flows are the finest granularity of QoS classification in a PDU session. QoS flows are identified within a PDU session by a QoS Flow Identifier (QFI) that is carried in the encapsulation header over the NG-U interface.

[0035] 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 the PDU sessions, and additional DRBs for the QoS flows of the PDU sessions can be configured later (when it is up to the NG-RAN), e.g. as described above with reference to Fig. 3. The NG-RAN places packets belonging to different PDU sessions in different DRBs. The NAS level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, whereas the AS level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0036] Figure 5 shows the non-roaming reference architecture for 5G NR (see TS 23.501 v16.1.0, section 4.23). Application Functions (AFs), such as external application servers hosting 5G services, as illustrated in Figure 4, interact with the 3GPP core network to provide services. For example, they may access the Network Exposure Function (NEF) to support applications that affect traffic routing, and interact with the policy framework for policy control such as QoS control (see Policy Control Function (PCF)). Based on the operator's deployment, application functions that are deemed trusted by the operator can directly interact with the relevant network functions. Application functions that are not allowed by the operator to directly access network functions interact with the relevant network functions using the external exposure framework via the NEF.

[0037] Figure 5 shows 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) (operator provided services, internet access, third party services, etc.). All or part of the core network functions and application services may be deployed and run on a cloud computing environment.

[0038] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, in operation, transmits a request including QoS requirements for at least one of URLLC, eMBB and mMTC services to at least one of 5GC functions (e.g., NEF, AMF, SMF, PCF, 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.

[0039] <CORESETとサーチスペース> A Physical Downlink Control Channel (PDCCH) is a physical layer (L1) channel for the downlink that carries downlink control information (DCI). In NR, a UE monitors (e.g., blindly decodes) PDCCH candidates in a control resource set (CORESET) using one or more search spaces (SS). Thus, the physical resources on which the PDCCH is transmitted are configured using the CORESET and the search space. Both the CORESET and search space configurations are semi-statically signaled via Radio Resource Control (RRC) signaling using the SearchSpace information element (IE) and the ControlResourceSet IE. Each search space is associated with one CORESET.

[0040] CORESET defines, among other configuration parameters, the frequency resource (e.g., a full chunk of 6 resource blocks (RBs) in the bandwidth part (BWP)) and the duration of the PDCCH candidates (e.g., 1, 2, or 3 symbols).

[0041] The search space defines, among other configuration parameters, the PDCCH monitoring occasion in time (e.g., at which slot and at which symbol the UE starts monitoring PDCCH candidates). The IE SearchSpace defines where and how to search for PDCCH candidates. A UE may be configured with multiple search spaces. Note that a search space is also called a search space set.

[0042] 3GPP has discussed the concept of configuring two groups of Search Space Sets (abbreviated as SSS or SS Sets) for monitoring the PDCCH. This concept is specifically designed for operation in unlicensed radio spectrum, where a gNB must first acquire a channel before it is allowed to transmit the PDCCH.

[0043] A search space may be associated with an SSS group identified by a group ID, and thus the search space may be switched by referencing the group ID, for example, to change monitoring opportunities or other parameters in unlicensed operation.

[0044] <NRマルチビーム> NR provides for directional transmission using beamforming, where a base station or transmitting / receiving point transmits and receives using directional beams. For example, for NR operation at higher frequencies (e.g., bands located above 52 GHz), directional transmission using beamforming can be used to concentrate energy or transmit power to overcome attenuation in these higher frequency bands.

[0045] An example of multi-beam operation is the time-division multiplexing (TDM) transmission of beams, which is sometimes called beam sweeping. In the TDM transmission of beams, the transmitter aggregates the transmission power in one direction (of beams) at the same time. TDM may be performed to reach the intended coverage and / or as a result of hardware limitations, such as the transmitter having an analog beamformer. To avoid interference between different beams, different beams are transmitted or generated with different symbols. Another example of multi-beam operation is the frequency-division multiplexing (FDM) transmission of beams, where different beams are transmitted with different frequency resources (e.g. bandwidth portions). Similar to the TDM of beams, the FDM transmission of beams can also avoid interference between different beams.

[0046] An example of TDM beam operation for transmitting SSBs (Synchronization Signal Blocks or SS Blocks) is shown in Figure 6. As shown, the SSBs are transmitted in different non-overlapping and non-adjacent 4-symbol time intervals in each of several different beams over an SSB burst duration of, for example, 20 ms. Since the SSBs carry the same information in each beam (except for the beam index), the base station does not need to consider which UEs are served by which beam.

[0047] However, TDM beam operation may also be used to transmit a group-common PDCCH (e.g., DCI format scrambled with an RRC-configured RNTI, such as SFI-RNTI (Slot Format Indication RNTI (Radio Network Temporary Identifier)), INT-RNTI (Interruption RNTI), or PS-RNTI (Power Saving RNTI)). For example, as shown in FIG. 7, each beam may serve a group of UEs located in the same beam direction, and the group-common PDCCH is specific to the group of UEs since it carries dedicated control information for each group of UEs. In such a case, when a UE moves from one beam to another, it should also change the monitoring occasion accordingly.

[0048] Although the above example describes a group-common PDCCH that carries group-common DCI specific to a group of UEs connected to a base station on the same beam, the present disclosure is also applicable to a UE-specific PDCCH.

[0049] In one example of NR mechanism, the beam for transmitting PDCCH by the gNB is signaled by the Transmission Configuration Indicator (TCI) state of the CORESET. The TCI state may be signaled via a Medium Access Control (MAC) control element (CE) or DCI. After receiving the new TCI state signal, the UE adjusts its Rx spatial filter according to the new beam at a predefined operation timing (e.g., 3 ms after the UE sends an ACK for the message carrying the MAC CE).

[0050] However, since changing the monitoring occasion (MO) requires another RRC signaling to change the search space settings as a second step, the UE still monitors the PDCCH on the previous occasion corresponding to the previous beam or TCI state.

[0051] In the above mechanism, beam switching (e.g., notifying the UE of a new transmission beam from the gNB) and PDCCH monitoring opportunity switching are performed as two separate steps and are controlled by separate signals, i.e., TCI status notification (e.g., via MAC CE or DCI) and separate RRC signaling for changing the MO.

[0052] Changes in the RRC configuration take effect rather slowly, so the above beam switching and PDCCH configuration change mechanisms may have difficulty meeting the requirements for fast beam adaptation, for example when operating at high frequencies.

[0053] Furthermore, in the above NR mechanisms, the operation timing of the RRC configuration is mostly undefined. For example, the timing is effective as soon as the RRC configuration is correctly received. This timing may vary since it depends on whether an RLC retransmission was required to deliver the RRC command. For example, the UE may change the RRC configuration after successful reception of the RRC configuration, but this may only occur after one or multiple retransmissions, resulting in ambiguous RRC operation timing. Such undefined switching timing may lead to mismatch between beam switching and monitoring opportunity switching timing.

[0054] Furthermore, this mechanism requires that RRC signaling is sent to the UE to change the monitoring opportunity every time a beam switch occurs, and therefore the required MO change due to the beam switch results in increased signaling overhead.

[0055] The present disclosure provides efficient signaling that enables a UE to change PDCCH monitoring opportunities accordingly when moving from one beam to another, e.g., techniques for PDCCH monitoring adaptation for multi-beam operation are provided.

[0056] In LTE and NR, a terminal is called a user equipment (UE). It may be a mobile device or communication device such as a wireless phone, a smartphone, a tablet computer, a Universal Serial Bus (USB) stick, etc., that has the functionality of a user equipment. However, the term mobile device is not limited thereto, and in general, a repeater may also have the functionality of such a mobile device, and a mobile device may also function as a repeater.

[0057] A base station is a network node or a scheduling node that forms part of a network that serves, for example, terminals. A base station is a network node that provides wireless access to terminals. For example, a base station is called a gNB in ​​NR.

[0058] In the present disclosure, a user equipment (UE) 860 is provided that includes a transceiver 870 and a circuit 880 as shown in FIG. 8. The circuit 880 (or "UE circuit") monitors a first time or frequency resource for a first physical downlink channel in a first beam. The transceiver 870 (or "UE transceiver") receives, in operation, a signal to initiate a switch from the first beam to a second beam. At the timing of the switch to the second beam, the UE circuit 880, in operation, switches to the second time or frequency resource based on the signal to initiate the switch and based on the notification of the second time or frequency resource to be monitored for the second PDCCH in the second beam. The first PDCCH and the second PDCCH are specific to the UE or a respective group of UEs including the UE 860.

[0059] For example, the UE circuitry 880 includes a PDCCH resource monitor and switching circuitry 885. An example of a PDCCH resource monitor and switching circuitry 885 is shown in Figure 9 and includes a PDCCH resource monitor circuit 936 that, in operation, monitors a first time or frequency resource for the first PDCCH and a second time or frequency resource for the second PDCCH, and includes a PDCCH resource switching circuit 937 that switches to the second time or frequency resource when switching to the second beam.

[0060] Further, a scheduling node 810 is provided, also shown in FIG. 8, comprising a transceiver 820 (or “SN transceiver”) and a circuit 830 (or “SN circuit”). The SN circuit 830, in operation, when serving a UE in a first beam, assigns a first PDCCH to a first time or frequency resource according to an association between a plurality of beams including the first beam and corresponding time or frequency resources. The SN transceiver 820, in operation, transmits a signal to initiate a switch of the UE to a second beam of the plurality of beams. The SN circuit 830, in operation, when serving a UE in a second beam, assigns a second PDCCH to a second time or frequency resource according to an association between the plurality of beams and corresponding time or frequency resources. The first PDCCH and the second PDCCH are specific to the UE or a respective group of UEs including the UE.

[0061] For example, the SN circuit 830 includes a PDCCH resource allocation circuit 835 that, during operation, allocates the PDCCH to a time or frequency resource, e.g., allocates the first PDCCH and the second PDCCH to a first time or frequency resource and a second time or frequency resource, respectively.

[0062] The SN circuit 830 considers the timing of the UE's beam switching when allocating the PDCCH to the time or frequency resources. The scheduling node 810 needs to allocate the PDCCH such that the UE receives the PDCCH on the second time or frequency resource no earlier than the UE achieves beam switching to the second beam, taking into account the propagation delay of the transmitted signal. In the allocation, the scheduling node also needs to ensure that the UE receives the last PDCCH on the first time or frequency resource by the time the UE starts adjusting for beam switching to the second beam.

[0063] The scheduling node 810 and the UE 860 communicate through a wireless channel realized by multiple beams. Corresponding to the above-mentioned UE 860 and the scheduling node 810, a communication method for the UE and a communication method for the base station are provided, the steps of which are shown in FIG.

[0064] The UE method includes a step S1020 of monitoring a first time or frequency resource for a first PDCCH in a first beam. In step S1040, the UE receives a signal to initiate a switch from the first beam to a second beam. As shown in FIG. 10, the signal is received from a scheduling node (or one or more TRPs controlled by the scheduling node). Then, at the timing to switch to the second beam, the UE switches in step S1060 to a second time or frequency resource monitored for a second PDCCH in the second beam. In step S1060, the switch is performed based on the signal and the notification of the second time or frequency resource. In the UE method, the first PDCCH and the second PDCCH are UE-specific PDCCHs or group-specific PDCCHs specific to a group including the UE.

[0065] The method of the scheduling node includes a step S1010 of allocating a first PDCCH to a first time or frequency resource when serving the UE in a first beam. The method further includes a step S1030 of transmitting a beam switch signal to initiate switching of the UE to a second beam. The method also includes a step S1050 of allocating a second PDCCH to a second time or frequency resource. The steps S1010 and S1050 of allocating PDCCHs to respective resources are performed based on and according to an association of multiple beams with corresponding time or frequency resources, e.g., an association or pegging of the first beam with the time or frequency resource and an association of the second beam with the second time or frequency resource. In the method of the scheduling node, the first PDCCH and the second PDCCH are UE-specific PDCCHs or group-specific PDCCHs specific to a group including the UE.

[0066] The scheduling node considers the timing of the beam switching of the UE when allocating the PDCCH to the time or frequency resource. For example, in step S1050, the UE receives the PDCCH on the second time or frequency resource not earlier than the UE achieves the beam switching to the second beam, taking into account the propagation delay of the transmitted signal. Step 1050 also ensures that the UE receives the last PDCCH on the first time or frequency resource by the time the UE starts adjusting for the beam switching to the second beam.

[0067] Since the UE and the scheduling node are interrelated devices, any details, examples, or embodiments disclosed for the UE should be understood to have a corresponding one for the scheduling node, even if not explicitly disclosed. Furthermore, any details of device operation should be understood to correspond to method steps, and vice versa. For example, an operation or step of a UE (or UE transceiver) receiving a signal or transmission corresponds to a step of a scheduling node (or SN transceiver) transmitting the same signal.

[0068] The time or frequency resource is a time or frequency resource for monitoring the PDCCH. For example, in the case of TDM, the time resource is a temporal monitoring opportunity of one or more search spaces. In the case of FDM, the frequency resource may include a resource block or a set of resource blocks of the CORESET.

[0069] For example, each beam may be signaled by a corresponding Transmission Configuration Indicator (TCI) state, which may be a TCI state that specifies the SSB or reference signal (e.g., CSI-RS: Channel State Information Reference Signal) transmitted in the beam.

[0070] The beam switching of the UE from the first beam to the second beam may be performed with the change of the UE's position from the direction of the first beam to the direction of the second beam. For example, the base station decides to switch the serving beam of the UE based on the results of channel measurements or power measurements (e.g., reference signal received power, the measurement results being transmitted from the UE to the scheduling node) performed by the UE for different beams.

[0071] As mentioned above, the switch from the first time or frequency resource to the second time or frequency resource is performed based on a signal that initiates the switch to the second beam. Such a signal may be a MAC CE, or a DCI. Furthermore, one DCI may include a beam switch notification for one UE or a group of UEs. Thus, the beam switch triggers the adaptation of the PDCCH monitoring opportunity.

[0072] Furthermore, the switching to the second time or frequency resource is also performed based on the notification of the second time or frequency resource. According to further described embodiments, the UE may receive the notification from the base station and / or store the notification in a memory, such as a memory in the UE or a memory device, such as a subscriber identity module (SIM), in which the UE has a memory interface. When the notification is sent to the UE, the notification of the time or frequency resource may be included in a signal to initiate beam switching or in a separate signal. The signal to initiate beam switching may be a MAC CE or DCI, and the separate signaling may be a MAC CE, DCI, RRC signaling, etc.

[0073] The UE performs the switching at the operation timing of switching the beam. Correspondingly, the scheduling node starts allocating the second PDCCH to the second resource from the timing when the UE switches from the first beam to the second beam. For example, since the scheduling node knows the operation timing of the UE to switch to the second beam, the scheduling node allocates the second PDCCH to the second time resource or frequency resource from the time when it knows that the UE has completed the switching, taking into account the possibility of propagation delay. From this timing, the scheduling node no longer allocates the first PDCCH for the UE to the first resource.

[0074] Each of the multiple beams is associated with an associated time or frequency resource of the multiple time or frequency resources, meaning that transmission and / or reception on that beam occurs on the time and / or frequency resource assigned to the beam.

[0075] The association of beams with time or frequency resources may be stored in the scheduling node and may be known to the UE, for example in a stored configuration (e.g., a hard-coded or static configuration) or in a semi-statically signaled configuration via higher layer signaling, such as RRC signaling.

[0076] In some embodiments described in more detail, the notification of the second time or frequency resource indicates an association of a plurality of beams, including a first beam and a second beam, with a plurality of corresponding time or frequency resources, including a first time or frequency resource associated with the first beam and a second time or frequency resource associated with the second beam. For example, the UE (or more specifically, the UE transceiver 870) receives a notification of a beam to switch (to the second beam) (sent from the scheduling node) by a signal to initiate a beam switch, and knows the time or frequency resource to be switched (to the second resource) from the association of the beam with the time or frequency resource. In another example, the SN transceiver 820, in operation, transmits RRC signaling indicating the association of a plurality of beams with the corresponding time or frequency resources.

[0077] An exemplary embodiment of a method for a UE and a scheduling node is shown in Figure 11. In addition to the method steps shown in Figure 10, the scheduling node method includes a step S1105 of configuring an association of multiple beams with corresponding time or frequency resources. The SN circuitry 830 may generate this configuration, and the SN transceiver 820 may transmit the configuration to the UE in step S1106 to be received using the UE transceiver 870.

[0078] As mentioned above, the first PDCCH and the second PDCCH may be specific to a group of UEs including the UE. For example, the first PDCCH and the second PDCCH may be group-common PDCCHs as shown in Figure 7, where the first PDCCH is used for control information (e.g., scheduling information) for UEs served by the first beam, and the second PDCCH carries control information for UEs served by the second beam. Thus, when the UE switches from the first beam to the second beam, the scheduling node stops signaling control information for scheduling the switched UE via the first PDCCH and starts signaling control information for the UE in the second beam.

[0079] However, the present disclosure is not limited to a group-common PDCCH, but may also be applied to a UE-specific PDCCH.

[0080] <time or frequency offset> In some embodiments, as an association of beams with time or frequency resources, multiple beams are associated with corresponding offsets in time or frequency.

[0081] For example, each beam (or beam usage state, e.g., each TCI state) among the beams is associated with an offset, e.g., an offset with respect to the time or frequency resources of a reference beam for the UE to monitor the PDCCH. An example of a reference beam may be a beam for transmitting a given SSB or CSI-RS. As a result, once the UE knows the time or frequency resources of the reference beam, the UE can determine the corresponding time or frequency resources for monitoring the PDCCH in the notified new beam by applying the offset associated with the beam notified by the beam switching signal. Note that the reference beam may be defined as a beam with offset=0, and its corresponding time or frequency resources may also be flexibly configured by the UE, e.g., via a search space and / or a control resource set configuration.

[0082] The offset may be configured with respect to different granularities, such as the number of symbols (symbol granularity), the number of slots, the number of multislots (e.g., by multiple slots), the number of CORESET durations (e.g., the duration of PDCCH candidates or monitoring opportunity candidates configured in the CORESET), or a combination of one or more of the above. To enable TDM of a CORESET with different beams, a scheduling node such as a gNB may ensure that the granularity of the offset is equal to or greater than the duration of the CORESET to avoid time overlap between monitoring opportunities of different beams.

[0083] Examples of options for indicating the association of beams with offsets are given below:

[0084] Option 1: The association of multiple beams with corresponding offsets is defined by a beam usage configuration via radio resource control (RRC) signaling, which may be an information element (IE) in RRC signaling that configures parameters related to transmission in a particular beam, such as a TCI-State information element (IE) signaled by RRC signaling.

[0085] Option 2: The association of multiple beams with corresponding offsets is defined by configuration of frequency resources via radio resource control (RRC) signaling, e.g., the definition is signaled in a ControlResourceSet IE by RRC signaling.

[0086] Option 3: The offset is defined in the specification of the standard. For example, the UE includes a memory or an interface for a memory, and the memory stores an association of multiple beams with corresponding offsets according to the specification of the standard.

[0087] When the CORESET is configured in the UE, multiple TCI states (or, more generally, notifications of multiple beams or beam usage states) may be included in the CORESET configuration, i.e. the UE may obtain multiple associated offsets if the association of offsets with beam usage or TCI states is already configured in the TCI-State IE (see option 1 above), if it is configured directly in the ControlResourceSet IE (see option 2 above), or if it is defined in the standard specification and stored in the UE memory (see option 3).

[0088] When the UE receives a signal (e.g., a MAC CE or DCI) to switch to the second beam including a beam switching command to activate the use of the second beam as one of the configured beam usage states, such as a TCI state for PDCCH monitoring, the UE starts applying the associated offset to the PDCCH monitoring opportunity while switching to the new beam (the second beam).

[0089] FIG. 12 illustrates example method steps for a UE in an embodiment in which time or frequency resources associated with each of a plurality of beams correspond to an offset.

[0090] In step S1201, the UE is informed of the association of beams and offsets, for example by hard-coding according to the specifications of the standard or by RRC. In step S1202 (corresponding to step S1106 in FIG. 11), a CORESET for PDCCH monitoring is configured in the UE, and multiple beam usage states (e.g., TCI states) including corresponding offsets are configured in the CORESET (e.g., according to option 1, 2 or 3 above).

[0091] For option 1, the offset can be obtained through ControlResourceSet → TCI State → Offset parameter. For option 2, the offset can be obtained through the ControlResourceSet itself. For option 3, the offset can be obtained from ControlResourceSet → TCI State → Offset. The difference with option 1 is that in option 3, the offset value for each TCI state is already pre-stored in the UE memory and no offset parameter is provided in the TCI State IE.

[0092] Further, in step S1203, the search space is configured by the RRC to the UE, from which the UE knows the PDCCH monitoring opportunities. These monitoring opportunities can be considered as reference beam opportunities (e.g., with zero offset). In step S1204 (corresponding to step S1040 in Figs. 10 and 11), the UE receives a MAC CE or DCI as a signal to initiate switching to a new beam (second beam) to activate one of the TCI states configured in the CORESET. Then, in step S1205, the UE applies an offset corresponding to the activated TCI state to the PDCCH monitoring opportunities as soon as the TCI state becomes active (e.g., starting from the timing of switching to the new beam or TCI state according to step S1060).

[0093] According to option 1 above, the association between the TCI state and the time offset is signalled to the UE via the TCI-State information element by RRC signalling, as highlighted in the code example below.

[0094]

number

[0095] In the above example, the offset is set in number of symbols, but it may be set in number of slots or number of multislots. A further example in which the offset is set with the granularity of the duration of the CORESET is shown below.

[0096]

number

[0097] As an example of option 2 shown in the code below, the association between the TCI state and the time offset is signaled to the UE via the ControlResourceSet IE, which is an information element that configures the CORESET, and the CORESET contains multiple TCI states with associated time offsets.

[0098]

number

number

[0099] According to option 3 above, the offset is defined in the standard specifications. An example is shown in Table 1 below, where the offset is defined relative to the SSB of multiple beams.

[0100] [Table 1]

[0101] In the definition of Table 1 above, a possible example of how the step size (parameter "StepSize") can be defined is the duration of the CORESET or the number of symbols and / or the number of slots. As a further example, the step size may be defined as e.g. the CORESET duration + x symbols, where "x symbols" is provided as one or more additional symbol intervals to allow for beam switching time of the gNB. The definition of the step size may be provided, for example, in the standard or in a broadcast via system information.

[0102] <Search Space Group> In some embodiments, the beams are associated with a corresponding group of search spaces that define the temporal monitoring occasions, and thus the association of the beams with the time resources is that of a beam to a search space group.

[0103] Here, different groups of search spaces (or "search space sets"), including different MOs, are configured for the UE, and each group is associated with a beam usage. For example, in the search space configuration (e.g., SearchSpace IE in RRC), multiple search space groups are defined, each having the same number of beams and distinguished from the other by different monitoring occasions that do not overlap in time. Each group is tied to a TCI state. The different groups are identified by a group ID that can serve the UE and has a sufficient number of bits to accommodate (or signal) the number of multiple configured beams (e.g., TCI states corresponding to the beams) that the UE can switch to. For example, if the number of beams (or configured TCI states) is greater than 2, the number of bits of the group signaling or group ID is greater than 1. When the UE is informed of the new beam usage via a signal to initiate a beam switch, the UE switches to the corresponding group.

[0104] Multiple groups of search spaces are configured for the UE, and the groups differ at least by monitoring occasions. As mentioned above, different MOs in different groups do not overlap in time to enable TDM beamforming operation. For example, the scheduling node ensures that monitoring occasions of groups tied to or associated with different beams do not overlap in time.

[0105] Each group is associated with one beam (e.g., TCI state), and such association or association may be maintained by the scheduling node without the knowledge of the UE.

[0106] Alternatively, the association of multiple beams with the corresponding group of search spaces is defined by configuration of the search spaces via RRC signaling. For example, the binding may be signaled to the UE when configuring the group by RRC (e.g., the associated TCI state ID may be maintained in the search space configuration such as the SearchSpace IE, or the associated group ID may be maintained in the TCI state configuration such as the TCI-State IE in the highlighted code example below).

[0107]

number

[0108] After the UE receives a beam switching command included in a signal initiating beam switching (e.g., via MAC CE or DCI), in addition to switching to the new beam, the UE also switches to the corresponding search space group for PDCCH monitoring.

[0109] If the UE is not aware of the binding between a beam and the associated search space group, it must receive an explicit group switch notification (e.g., via DCI). Such an explicit group switch notification does not need to be signaled if the UE has previously been informed of the binding.

[0110] FIG. 13 shows method steps of a UE method for switching search space groups when the UE knows from the configuration received in RRC signaling the binding or association between the search space groups and the TCI states corresponding to the beams.

[0111] In step S1301, the RRC configures the UE with a CORESET for PDCCH monitoring, which includes multiple beam usage states, such as TCI states. Furthermore, the RRC configures the UE with multiple search space groups, where the monitoring opportunities of different groups do not overlap in time, and each group is linked to a beam usage state (S1302, which corresponds to step S1106). As a result of step S1302, the UE knows the corresponding PDCCH monitoring opportunities for each beam. In step S1303, which embodies step S1040, the UE receives a signal to initiate a switch from one beam to another beam, e.g., a MAC CE or DCI that activates one of the configured TCI states associated with the new beam. Finally, in step S1304, which embodies step S1060, the UE switches to the search space group corresponding to the new beam when switching to the new beam, e.g., when a new TCI state is activated.

[0112] However, as mentioned above, the association or binding between beams and search space groups may be maintained by the scheduling node without the UE being aware of the binding. An example of steps of the UE method corresponding to the case where the binding between search space groups and beam usage / TCI states is not known to the UE is shown in FIG. 14. The example of FIG. 14 differs from FIG. 13 in steps 1402 and S1403. In particular, in step S1402, multiple search space groups including non-overlapping MOs in different groups are configured in the UE by the RRC. Each configured search space group is bound to a beam usage state, but such binding is maintained by the scheduling node without the UE being aware of it. In step S1403, the UE receives a signal such as a MAC CE or DCI that activates one of the configured TCI states and one of the SS groups. Both switching commands to switch search space groups and beams may be provided in the same signal or in different signals.

[0113] For example, multiple search space groups defining temporal monitoring opportunities are configured in the UE, and a signal initiating beam switching (e.g., MAC CE or DCI) notifies the UE of a search space group associated with a second beam among the multiple search space groups as a second time resource.

[0114] As another example, a plurality of search space groups defining temporal monitoring occasions are configured for the UE, and the UE receives a first signal initiating a switch from a first beam to a second beam and a second signal including a notification of a search space group associated with the second beam as a second time resource among the plurality of search space groups, for example, a MAC CE as the first signal initiates a beam switch and a DCI as the second signal initiates a search space group switch, or both signals are transmitted by DCIs with different bit fields.

[0115] <Activation conditions> In some embodiments, the indication of the second time or frequency resource and the indication to switch to the second time or frequency resource are received by the UE in RRC signaling.

[0116] For example, before the UE switches beams according to a (DCI or MAC CE) signal initiating the switch, the scheduling node changes the configuration of the PDCCH monitoring opportunity, with the condition that the changed configuration is activated by the UE at the same time that the UE activates the new beam. Before informing the UE to switch beams (or TCI states), the scheduling node first reconfigures the search space monitoring opportunity by RRC, with the condition that the new PDCCH monitoring opportunity starts to be activated when the UE switches to the new beam (TCI state). Such reconfiguration can be done using the SearchSpace IE, an example of which is shown below.

[0117]

number

[0118] As seen in the above IE of the search space, in addition to the position of the monitoring opportunity set by the parameters monitoringSlotPeriodicityAndOffset (slot position / period) and monitoringSymbolsWithinSlot (symbol position within slot), a condition called, for example, activatedByTCI is included as notification of switching to a new monitoring opportunity when switching to a new beam. When the condition is set to be valid, the UE switches the monitoring opportunity (or other time or frequency resource) at the time instance of the beam switch.

[0119] In another example below, the condition is signaled in relation to a system frame number (SFN), such that the UE activates the new search space to be switched upon beam switching in the signaled frame (signaled by the parameter activationReference).

[0120]

number

[0121] FIG. 15 shows method steps executed by the UE in an embodiment where MO switching is activated by a condition in RRC signaling. In step S1501, a CORESET for PDCCH monitoring is configured in the UE by RRC signaling, which includes multiple beam usage states (step S1501). One of these beam usage states is activated, for example, the TCI state with the lowest ID is activated by default before the UE receives a MAC CE or DCI for activation, or as another possibility, the SSB beam or CSI-RS beam that the UE identified during the random access procedure is activated without receiving an activation command in MAC CE or DCI. The activated beam usage state corresponds to the beam currently serving the UE. Furthermore, in step S1502, a search space is configured in the UE by RRC, from which the UE knows the PDCCH monitoring opportunity corresponding to the activated beam usage state. In step S1503, the UE moves to the coverage area of ​​another beam. Although not explicitly shown in the remaining flow charts, such a move to another coverage area may occur in each of the disclosed embodiments. After moving to the new coverage area, in step S1504, the UE receives RRC signaling for changing the MO of the search space, including a condition for TCI activation, e.g., a new search space information element including a notification for switching to a second time or frequency resource (e.g., a condition or timing related to a frame number) at the timing of switching to the second beam. Then, in step S1505, after receiving a signal such as a MAC CE or DCI by CORESET initiating a switch to another TCI state set in step S1501, the UE switches to a new MO for monitoring the PDCCH when switching to the new beam, for example by activating a new TCI state (step S1506).

[0122] The techniques provided in this disclosure enable the coordination of beam switching and switching of time or frequency resources, such as MO for group-common or UE-specific PDCCH. In particular, the embodiment entitled "Conditions for Activation" facilitates the alignment of operation timing between beam switching (e.g., via MAC CE or DCI) and MO reconfiguration (via RRC). The alignment of operation timing of beam and MO switching is also facilitated by the embodiments described in "Time or Frequency Offset" and "Group of Search Space". In addition, fast joint beam and MO switching is facilitated in a resource-efficient manner with no need for additional RRC configuration to switch to new time or frequency resources, reducing time and signaling overhead.

[0123] As mentioned above, the present disclosure is applicable to a (group) common PDCCH and also to a UE-specific PDCCH. As mentioned above, a possible use case for applying the disclosed beam switching technique to a group common PDCCH is a multi-beam scenario where UEs of different groups are served in different beams.

[0124] A use case for applying the disclosed technology to a UE-specific PDCCH may be an unlicensed operation. For example, a scheduling node (e.g., gNB) first transmits a common (e.g., group-common) PDCCH on a wide beam to acquire the channel and initiate channel occupancy. Then, multiple narrow beams are TDMed to transmit UE-specific PDCCHs to different UEs within the range of channel occupancy declared by the wide beam. In such a case, a beam usage notification may be signaled to a group of UEs at the start of channel occupancy using the group-common PDCCH via the wide beam.

[0125] Meanwhile, in some use cases, the disclosed technique may be applicable only to group-common PDCCH and not to UE-specific PDCCH. Specifically, as an example shown in FIG. 7, different time or frequency resources of the group-common PDCCH are associated with different beams. However, UE-specific PDCCHs for different UEs are transmitted on the same time and frequency resources (e.g., spatial-division multiplexing (SDM)). The advantage of such an operation is to improve resource utilization efficiency. For example, the scheduling node can set UE-specific MO for a group of UEs to be concentrated at the beginning of a slot, such as the first two symbols (regardless of the serving beam), and then fill the remaining symbols in the slot with PDSCH, since other symbols do not need to be reserved for PDCCHs of other beams.

[0126] Furthermore, some examples and embodiments are provided in which MO adaptation in the time domain is considered to be performed together with and simultaneously with beam switching. However, the present disclosure is generally applicable to time or frequency resources as MO. Thus, the present disclosure is equally applicable to the frequency domain, such as when different beams are frequency division multiplexed (FDM) in different BWPs or component carriers. In such cases, beam switching triggers MO adaptation in the frequency domain. For example, the association of a beam with a corresponding frequency resource is in the association of a beam (or TCI state) with a frequency offset (e.g., signaled by a TCI state IE or a search space IE), a CORESET, a group of CORESETs, or a BWP configuration.

[0127] Additionally, the multiple beams referred to in this disclosure may be transmitted or generated by one cell or transmission and reception point (TRP) or may be transmitted or generated by different TRPs / cells.

[0128] Furthermore, the present disclosure is applicable to both licensed and unlicensed spectrum operation (see, for example, the above-mentioned scenario of UE-specific PDCCH).

[0129] The present disclosure facilitates meeting the low latency requirements for fast and frequent beam switching when applied to high frequency operations such as millimeter wave operations, however, the present disclosure is not limited to any operating frequency band.

[0130] In some embodiments, the signal initiating the beam switching or a separate signal, such as a MAC CE or DCI, includes the notification of the second time or frequency resource. Above, an example is described in which the search space group to be switched to is notified via a MAC CE or DCI without the UE knowing the association of the search space group with the beam or beam usage state. Similarly, when the beam usage is notified to the UE via a first signal or a second signal, such as a MAC CE or DCI, the offset value (e.g., offset to a reference beam) may be directly notified.

[0131] As mentioned above, the offset described in some embodiments is an offset with respect to the time or frequency resources of the reference beam. The offset concept allows for a flexible position of each beam. However, instead of using an offset, different MOs corresponding to different beams may be directly configured in the configuration of the search space, for example via RRC. Such a configuration may facilitate defining different MOs for different beams in a more flexible way, for example with respect to the location and size / duration of the MOs in time and / or frequency.

[0132] In summary, in a first embodiment, a user equipment (UE) is provided, comprising: a circuit for monitoring, in operation, a first time resource or frequency resource for a first PDCCH (physical downlink control channel) in a first beam; and a transceiver for receiving, in operation, a signal for initiating switching from the first beam to a second beam, wherein, at the timing of switching to the second beam, the circuit, in operation, switches to the second time resource or frequency resource to be monitored based on the signal and notification of a second time resource or frequency resource for a second PDCCH in the second beam, and the first PDCCH and the second PDCCH are specific to the UE or to each group of UEs including the UE.

[0133] In addition to the first embodiment, in a second embodiment, the notification of the second time resource or frequency resource notifies association of a plurality of beams, including the first beam associated with the first time resource or frequency resource and the second beam associated with the second time resource or frequency resource, with corresponding time resources or frequency resources.

[0134] In a third embodiment, provided in addition to the second embodiment, the multiple beams are associated with corresponding offsets in time or frequency.

[0135] In a fourth embodiment provided in addition to the third embodiment, the association of the multiple beams with the corresponding offsets is defined by beam usage configuration via Radio Resource Control (RRC) signaling.

[0136] In a fifth embodiment provided in addition to the third embodiment, the association of the multiple beams with the corresponding offsets is defined by a frequency resource configuration via Radio Resource Control (RRC) signaling.

[0137] In a sixth embodiment provided in addition to the third embodiment, the UE comprises a memory that, in operation, stores associations of the plurality of beams with the corresponding offsets in accordance with a standard specification.

[0138] In a seventh embodiment, provided in addition to the second embodiment, the multiple beams are associated with corresponding groups of search spaces that define temporal monitoring occasions.

[0139] In an eighth embodiment provided in addition to the seventh embodiment, the seventh embodiment is configured in the UE, and the association of the multiple beams with corresponding groups of the search space is defined by configuration of the search space via RRC signaling.

[0140] In addition to the first or second embodiment, in a ninth embodiment, a plurality of groups of search spaces defining a time-based monitoring opportunity are configured in the UE, and the UE: a first signal initiating a switch from the first beam to the second beam; a second signal including a notification of a group of search spaces associated with the second beam as the second time resource among the plurality of groups of search spaces; Receive.

[0141] In addition to the first and second embodiments, in a tenth embodiment, multiple groups of search spaces defining temporal monitoring opportunities are configured in the UE, and the signal notifies the UE of a group of search spaces associated with the second beam among the multiple groups of search spaces as the second time resource.

[0142] In addition to the first and second embodiments, in an eleventh embodiment, the transceiver, during operation, receives radio resource control (RRC) signaling including notification of the second time resource or frequency resource and notification to switch to the second time resource or frequency resource at the timing of switching to the second beam.

[0143] Further, in a twelfth embodiment, a scheduling node is provided, comprising: a circuit for, when serving a user equipment (UE) in a first beam, allocating a first PDCCH (physical downlink control channel) to a first time resource or frequency resource in accordance with an association between a plurality of beams including the first beam and a second beam and corresponding time resources or frequency resources; and a transceiver for, when operating, transmitting a signal to initiate switching of the user equipment (UE) from the first beam to the second beam, wherein the circuit for, when serving the UE in the second beam, allocates a second PDCCH to a second time resource or frequency resource in accordance with the association between the plurality of beams and the corresponding time resources or frequency resources, and the first PDCCH and the second PDCCH are specific to the UE or a respective group of UEs including the UE.

[0144] In addition to the twelfth embodiment, in a thirteenth embodiment, the transceiver, in operation, transmits Radio Resource Control (RRC) signaling indicating the association of the multiple beams with the corresponding time or frequency resources.

[0145] In a fourteenth embodiment, a communication method for a user equipment (UE) is provided, comprising: a step of monitoring a first time resource or frequency resource for a first PDCCH (physical downlink control channel) in a first beam; a step of receiving a signal to initiate switching from the first beam to a second beam; and a step of switching to the second time resource or frequency resource to be monitored based on the signal and notification of a second time resource or frequency resource for a second PDCCH in the second beam at the timing of switching to the second beam, wherein the first PDCCH and the second PDCCH are specific to the UE or each group of UEs including the UE.

[0146] In a fifteenth embodiment, a communication method for a scheduling node is provided, comprising: when serving a user equipment (UE) in a first beam, allocating a first PDCCH (physical downlink control channel) to a first time resource or frequency resource in accordance with an association between a plurality of beams including the first beam and a second beam and corresponding time resources or frequency resources; transmitting a signal to initiate switching of the user equipment (UE) from the first beam to the second beam; and when serving the UE in the second beam, allocating a second PDCCH to a second time resource or frequency resource in accordance with the association between the plurality of beams and the corresponding time resources or frequency resources, wherein the first PDCCH and the second PDCCH are specific to the UE or a respective group of UEs including the UE.

[0147] It should be noted that the second to eleventh embodiments are similarly applicable to the scheduling node of the twelfth embodiment, and the thirteenth embodiment is similarly applicable to the user equipment of the first embodiment.

[0148] Furthermore, the steps performed by the circuit during operation, the steps performed by the transceiver during operation, and the steps performed by the memory during operation referred to in the above first to thirteenth embodiments of the UE and scheduling node correspond to the respective method steps.

[0149] Also provided is a non-transitory medium having stored thereon program instructions which, when executed on a processing circuit, such as a general purpose processor, cause the processing circuit to perform all of the steps of the method embodiments described above.

[0150] Furthermore, an integrated circuit for a communication device, such as a UE or a scheduling node, is provided, for controlling the communication device to perform all the steps of the above-mentioned method embodiments.

[0151] The present disclosure can be realized by software, hardware, or software interlocked with hardware. Each functional block used in the description of each embodiment above can be partially or entirely realized by an LSI (Large Scale Integration) such as an integrated circuit (IC), and each process described in each embodiment can be partially or entirely controlled by the same LSI or a combination of LSIs. The LSI may be formed as an individual chip, or a single chip may be formed to include some or all of the functional blocks. The LSI may include data input / output coupled thereto. Here, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. However, the technology for realizing an integrated circuit is not limited to an LSI, and may be realized using a dedicated circuit, a general-purpose processor, or a processor for a specific application. Furthermore, a field programmable gate array (FPGA) that can be programmed after the manufacture of an LSI or a reconfigurable processor that can reconfigure the connection and settings of circuit cells arranged inside the LSI may be used. The present disclosure can be realized as digital processing or analog processing. If future integrated circuit technologies replace LSI as a result of advances in semiconductor technology and other derived technologies, the functional blocks can be integrated using the future integrated circuit technologies. Biotechnology can also be applied.

[0152] The present disclosure may be implemented by any type of apparatus, device or system having communication capabilities, referred to as a communications apparatus.

[0153] A communication device may include a transceiver and processing / control circuitry. The transceiver may include and / or function as a receiver and a transmitter. The transceiver as a transmitter and receiver may include a Radio Frequency (RF) module including amplifiers, RF modulators / demodulators, etc., and one or more antennas.

[0154] Some non-limiting examples of such communications devices include telephones (e.g., mobile (cell) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (remote health and remote medical) devices, and vehicles (e.g., automobiles, airplanes, ships) that provide communications capabilities, and various combinations thereof.

[0155] The communications apparatus is not limited to being portable or mobile, but may include any type of apparatus, device or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "thing" in an "Internet of Things (IoT)" network.

[0156] Communications may include, for example, exchanging data via cellular systems, wireless LAN systems, satellite systems, and the like, as well as various combinations thereof.

[0157] A communications apparatus may include devices such as a controller or a sensor coupled to the communications device to perform the communications functions described in this disclosure. For example, a communications apparatus may include a controller or a sensor that generates control or data signals used by the communications device to perform the communications functions of the communications apparatus.

[0158] The communications equipment may also include infrastructure facilities such as base stations, access points, and any other equipment, devices or systems that communicate with or control equipment such as those in the non-limiting examples above.

[0159] Furthermore, various embodiments may also be implemented using software modules executed by a processor or directly in hardware. A combination of software modules and hardware implementation may also be possible. The software modules may be stored in any type of computer-readable storage medium. In particular, according to another implementation, a non-transitory computer-readable storage medium is provided. The storage medium stores a program that, when executed by one or more processors, causes the one or more processors to perform the steps of the method according to the present disclosure.

[0160] In summary, a UE, a scheduling node, and methods for the UE and the scheduling node are provided, the UE comprising: a circuit for monitoring, in operation, a first time or frequency resource for a first PDCCH (physical downlink control channel) in a first beam; and a transceiver for receiving, in operation, a signal for initiating a switch from the first beam to a second beam, the circuit for switching, in operation, to the second time or frequency resource to be monitored based on the signal and a notification of a second time or frequency resource for a second PDCCH in the second beam at the timing of the switch to the second beam, the first PDCCH and the second PDCCH being specific to the UE or a respective group of UEs including the UE.

Claims

1. A communication device, comprising: a circuit configured to monitor, during operation, a first time or frequency resource for a first physical downlink control channel (PDCCH) in a first beam; a transceiver that, in operation, receives a signal to initiate a switch from the first beam to a second beam; Equipped with At a timing of switching to the second beam, the circuit, in operation, switches to the second time resource or frequency resource to be monitored based on the signal and a notification of a second time resource or frequency resource for a second PDCCH in the second beam; The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Communications equipment.

2. The notification of the second time resource or frequency resource notifies association of a plurality of beams, including the first beam associated with the first time resource or frequency resource and the second beam associated with the second time resource or frequency resource, with the corresponding time resource or frequency resource. The communication device according to claim 1 .

3. the multiple beams being associated with corresponding offsets in time or frequency; The communication device according to claim 2 .

4. The association of the beams with the corresponding offsets is defined by a beam usage configuration via Radio Resource Control (RRC) signaling. The communication device according to claim 3.

5. The association of the beams with the corresponding offsets is defined by a frequency resource configuration via RRC signaling. The communication device according to claim 3.

6. the communication device comprising: a memory configured to store, in operation, an association of the plurality of beams with the corresponding offsets in accordance with a standard specification; The communication device according to claim 3.

7. the plurality of beams being associated with a corresponding group of search spaces that define a temporal monitoring opportunity; The communication device according to claim 2 .

8. The association of the plurality of beams with the corresponding group of search spaces is defined by a configuration of the search spaces via RRC signaling. The communication device according to claim 7.

9. A plurality of groups of search spaces defining temporal monitoring occasions are configured in the communication device; The communication device includes: a first signal to initiate a switch from the first beam to the second beam; a second signal including notification of a group of search spaces associated with the second beam as the second time resource among the plurality of groups of search spaces; To receive, 3. A communication device according to claim 1 or 2.

10. A plurality of groups of search spaces defining temporal monitoring occasions are configured in the communication device; The signal notifies a group of search spaces associated with the second beam among the plurality of groups of search spaces as the second time resource.

3. A communication device according to claim 1 or 2.

11. In operation, the transceiver receives RRC signaling including a notification of the second time resource or frequency resource and a notification to switch to the second time resource or frequency resource at a timing to switch to the second beam. The communication device according to claim 1 .

12. A scheduling node, In operation, when serving a communication device in a first beam, a circuit for allocating a first physical downlink control channel (PDCCH) to a first time resource or frequency resource according to an association between a plurality of beams including the first beam and a second beam and corresponding time resources or frequency resources; a transceiver that, in operation, transmits a signal to initiate a switch of the communication device from the first beam to the second beam; Equipped with When operating, the circuitry allocates a second PDCCH to a second time or frequency resource according to the association of the plurality of beams with the corresponding time or frequency resources when serving the communication device in the second beam; The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Scheduling node.

13. and wherein the transceiver, in operation, transmits Radio Resource Control (RRC) signaling informing of the association of the plurality of beams with the corresponding time or frequency resources. A scheduling node according to claim 12.

14. A communication method for a communication device, comprising: monitoring a first time or frequency resource for a first physical downlink control channel (PDCCH) in a first beam; receiving a signal to initiate a switch from the first beam to a second beam; switching to the second time resource or frequency resource to be monitored based on the signal and a notification of a second time resource or frequency resource for a second PDCCH in the second beam at a timing of switching to the second beam; Including, The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Communication methods.

15. A communication method for a scheduling node, comprising: When serving a communication device in a first beam, assigning a first physical downlink control channel (PDCCH) to a first time resource or frequency resource according to an association between a plurality of beams including the first beam and a second beam and corresponding time resources or frequency resources; transmitting a signal to initiate a switch of the communication device from the first beam to the second beam; allocating a second PDCCH to a second time or frequency resource according to the association of the beams with the corresponding time or frequency resources when serving the communication device in the second beam; Including, The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Communication methods.

16. An integrated circuit configured to control a communications device, comprising: a control circuit configured to, during operation, monitor a first time or frequency resource for a first physical downlink control channel (PDCCH) in a first beam; a transceiver circuit that, in operation, receives a signal to initiate a switch from the first beam to a second beam; Equipped with At a timing of switching to the second beam, the control circuit, in operation, switches to the second time resource or frequency resource to be monitored based on the signal and a notification of a second time resource or frequency resource for a second PDCCH in the second beam; The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Integrated circuits.

17. An integrated circuit configured to control a scheduling node, comprising: A control circuit, in operation, when serving a communication device in a first beam, assigning a first physical downlink control channel (PDCCH) to a first time resource or frequency resource according to an association between a plurality of beams including the first beam and a second beam and corresponding time resources or frequency resources; a transceiver circuit that, in operation, transmits a signal to initiate a switch of the communication device from the first beam to the second beam; Equipped with The control circuit, in operation, when serving the communication device in the second beam, assigns a second PDCCH to a second time resource or frequency resource according to the association of the plurality of beams with the corresponding time resource or frequency resource; The first PDCCH and the second PDCCH are specific to the communication device or to a respective group of communication devices including the communication device. Integrated circuits.

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