User Equipment and Base Station Involved in Monitoring the Downlink Control Channel

Abstract

The present disclosure relates to a user equipment UE comprising: a processing circuit determines, for a timeslot group, one or more timeslots to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring opportunities in the one or more timeslots for receiving downlink control information. The determination of the monitoring timeslot is performed according to one or more of a first criterion that the monitoring timeslot includes a monitoring opportunity associated with a common search space of the downlink control channel, and a second criterion that the monitoring timeslot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel. The processing circuit then monitors the downlink control channel at the determined monitoring timeslot of the timeslot group.

Description

[Technical field]

[0001] The present disclosure is directed to methods, apparatus, and articles in communication systems, such as 3GPP® communication systems. [Background technology]

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working on technical specifications for the next generation of cellular technology, also known as the fifth generation (5G).

[0003] One objective is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios (e.g., see 3GPP TR 38.913 version 16.0.0, section 6), including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communication (mMTC). For example, eMBB deployment scenarios may include indoor hotspots, dense urban, rural, urban macro, and high speed, URLLC deployment scenarios may include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time control of vehicles, wide area monitoring, and control systems for smart grids, and mMTC deployment scenarios may include scenarios with a large number of devices with non-time-critical data transfer, such as smart wearables and sensor networks. eMBB and URLLC services are similar in that both require very high bandwidth, but differ in that URLLC services may preferably require ultra-low latency.

[0004] A second objective is to achieve forward compatibility: backward compatibility to Long Term Evolution (LTE, LTE-A) cellular systems is not required, thus facilitating the introduction of entirely new system designs and / or novel features. Summary of the Invention [Problem to be solved by the invention]

[0005] One non-limiting exemplary embodiment facilitates providing a procedure for a UE to perform an improved downlink control channel monitoring procedure. [Means for solving the problem]

[0006] In one embodiment, the techniques disclosed herein feature a user equipment UE comprising: a processing circuit for the UE determines, for two or more timeslot groups, one or more timeslots in the timeslot groups to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving downlink control information messages; A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; 4. Perform the procedure according to one or more of the following:

[0007] The processing circuitry then monitors the downlink control channel in the determined one or more monitor time slots of the time slot group.

[0008] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof. For example, an integrated circuit may control processing of a UE or a base station.

[0009] Further benefits and advantages of the disclosed embodiments and various implementations will become apparent from the specification and drawings. These benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and it is not necessary for all of the embodiments and features to be provided in order to obtain one or more of such benefits and / or advantages. [Brief description of the drawings]

[0010] The following embodiments are explained in more detail with reference to the accompanying drawings. [Figure 1] FIG. 1 is a diagram of an example architecture of a 3GPP NR system. [Diagram 2] FIG. 1 is a schematic diagram showing functional separation between NG-RAN and 5GC. [Diagram 3] FIG. 1 is a sequence diagram of an RRC connection setup / reconfiguration procedure. [Figure 4] 1 is a schematic diagram illustrating enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC) usage scenarios. [Diagram 5] FIG. 1 is a block diagram illustrating an example 5G system architecture for a non-roaming scenario. [Figure 6] A diagram showing the relationship between bandwidth parts, control resource sets (CORESETs), search spaces, search space sets, and PDCCH candidates. [Figure 7] FIG. 1 illustrates an example time domain structure in a communication system such as 5G NR, including radio frames, subframes, slots, and OFDM symbols with different subcarrier spacing. [Figure 8] FIG. 13 shows the resulting slot lengths and OFDM symbols for the high subcarrier spacing used in the new frequency range of 52.6-72 GHz. [Figure 9] FIG. 2 illustrates the use of timeslot groups to group timeslots in the time domain. [Figure 10] A diagram showing a downlink control channel with four beams, specifically beam sweeping of a common search space and reception by two UEs. [Figure 11] FIG. 13 shows the timing of the resulting beam-swept CSS, specifically, the CSSs are placed in different time slots within each time slot group, and it is assumed that the positions of the monitoring time slots of the two UEs are fixed. [Figure 12] FIG. 1 illustrates an exemplary simplified structure of a UE and a gNB. [Figure 13] FIG. 1 illustrates a structure of a UE with an exemplary implementation of an improved downlink control channel monitoring procedure. [Figure 14] 4 is a flow diagram of UE operation in accordance with an example implementation of an improved downlink control channel monitoring procedure. [Figure 15] FIG. 2 illustrates the structure of a base station with an exemplary implementation of an improved downlink control channel monitoring procedure. [Figure 16] 4 is a flow diagram of the operation of a base station participating in an exemplary implementation of an improved downlink control channel monitoring procedure. [Figure 17] FIG. 1 is a signaling diagram illustrating an example exchange between a UE and a gNB in ​​an example implementation of an improved downlink control channel monitoring procedure. [Figure 18] 1 is a flow chart of a UE operation according to an exemplary implementation of a first solution of an improved downlink control channel monitoring procedure. [Figure 19] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the first solution of the improved downlink control channel monitoring procedure. [Figure 20] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the first solution of the improved downlink control channel monitoring procedure. [Figure 21] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the first solution of the improved downlink control channel monitoring procedure. [Figure 22] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the first solution of the improved downlink control channel monitoring procedure. [Diagram 23] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the first solution of the improved downlink control channel monitoring procedure. [Figure 24] 13 is a flow diagram of a UE operation according to an exemplary implementation of a second solution of an improved downlink control channel monitoring procedure. [Diagram 25] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the second solution of the improved downlink control channel monitoring procedure. [Figure 26] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the second solution of the improved downlink control channel monitoring procedure. [Figure 27] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the second solution of the improved downlink control channel monitoring procedure. [Figure 28] A diagram showing the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the second solution of the improved downlink control channel monitoring procedure. [Figure 29] 13 is a flow chart of a UE operation, including checking whether a configured MO has been changed, according to an exemplary implementation of a second solution of an improved downlink control channel monitoring procedure. [Diagram 30] FIG. 30 illustrates the configuration of CSS MO and USS MO and the resulting Y monitoring time slots according to an exemplary implementation of the solution of FIG. 29. [Diagram 31] FIG. 2 illustrates the configuration of CSS MO and USS MO and the resulting Y monitoring time slots, and in particular the back-to-back problem. [Diagram 32] FIG. 31 illustrates the configuration of CSS MO and USS MO, the resulting Y monitoring time slots, and a method for solving the back-to-back problem of FIG. 30, particularly when applying the first solution. [Diagram 33] FIG. 31 illustrates the configuration of CSS MO and USS MO, the resulting Y monitoring time slots, and a method for solving the back-to-back problem of FIG. 30, especially when applying the second solution. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <5G NR system architecture and protocol stack> 3GPP continues to work on the next release of fifth-generation 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 in late 2017, allowing for the prototyping and commercial deployment of 5G NR-compliant smartphones.

[0012] In particular, the overall system architecture assumes a Next Generation-Radio Access Network (NG-RAN) with gNBs. The gNBs provide the UE-side termination of the NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols. The gNBs are interconnected with each other by an Xn interface. The gNBs are also connected to the Next Generation Core (NGC) by a Next Generation (NG) interface, more specifically to the Access and Mobility Management Function (AMF, e.g. a specific core entity running AMF) by an NG-C interface and to the User Plane Function (UPF, e.g. a specific core entity running 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 v16.46.0).

[0013] The NR user plane protocol stack (see, for example, section 4.4.1 of 3GPP TS 38.300) includes the PDCP (Packet Data Convergence Protocol, see section 6.4 of TS 38.300) sublayer, the RLC (Radio Link Control, see section 6.3 of TS 38.300) sublayer, and the 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 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 given in sub-clause 6 of TS 38.300. The functions of the RRC layer are listed in sub-clause 7 of TS 38.300.

[0014] For example, the MAC layer is responsible for multiplexing logical channels and scheduling and scheduling-related functions, including handling various numerologies.

[0015] 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.

[0016] NR use cases / deployment scenarios include eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable Low-Latency Communications), and mMTC (massive Machine Type Communication), which have diverse requirements for data rate, latency, and coverage. For example, eMBB is required to support peak data rates (20Gbps downlink, 10Gbps uplink) and effective (user-experienced) data rates that are about three times higher than those offered by IMT-Advanced. On the other hand, 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). -5Finally, mMTC preferably requires high connection density (1 million devices per square kilometer in urban environments), wide coverage in adverse environments, and ultra-long battery life (15 years) for low-cost equipment.

[0017] Therefore, OFDM numerology (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case may not be valid for other use cases. For example, low latency services may preferably require a shorter symbol length (and therefore a larger subcarrier spacing) and / or fewer symbols per scheduling interval (in other words, TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with small delay spreads. To maintain similar CP overhead, the subcarrier spacing needs to be optimized accordingly. NR may support multiple values ​​of subcarrier spacing. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, ... are currently being considered. Symbol length T u and the subcarrier spacing Δf is expressed by the formula Δf=1 / T u Similar to LTE systems, the term "resource element" can be used to denote the smallest resource unit consisting of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0018] 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 of the resource grid is called a resource element and is identified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 v16.46.0, e.g., section 4). For example, downlink and uplink transmissions are organized into frames with a duration of 10 ms, each frame consisting of 10 subframes of 1 ms duration each. In a 5g NR implementation, the number of consecutive OFDM symbols per subframe depends on the subcarrier spacing setting. For example, for a subcarrier spacing of 15 kHz, a subframe has 14 OFDM symbols (similar to an LTE-compatible implementation assuming a normal cyclic prefix). On the other hand, for a subcarrier spacing of 30 kHz, a subframe has two slots, each slot containing 14 OFDM symbols.

[0019] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 2 shows the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0020] In particular, the gNB and ng-eNB host the following main functions: - Radio Resource Management functions such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, dynamic allocation (scheduling) of resources to UEs in both uplink and downlink; - IP header compression, encryption, and integrity protection of data; - Selection of the AMF at UE attach time if routing to the AMF cannot be determined from information provided by the UE; - Routing of user plane data towards the UPF; - Routing of control plane information towards AMF; - Setting up and tearing down connections; - Scheduling and sending paging messages; - Scheduling and transmission of system broadcast information (sourced from AMF or Operation, Admission, Maintenance Function (OAM)); - Setting up measurements and reporting of measurements for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Support for network slicing; - QoS flow management and mapping to data radio bearers; - Support for UEs in RRC_INACTIVE state; - Non-Access Stratum (NAS) message delivery function; - Sharing of radio access networks; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0021] The Access and Mobility Management Function (AMF) hosts the following main functions: - Termination of Non-Access Stratum (NAS) signalling; - NAS signaling security; - Access Layer (AS) security controls; - 3GPP Core Network (CN) inter-node signalling for mobility between access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization including roaming privilege checks; - Mobility management control (subscription and policies); - Support for network slicing; - Selection of Session Management Function (SMF).

[0022] Additionally, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT / inter-RAT mobility (if applicable); - External PDU (Protocol Data Unit) Session Points for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and policy rule enforcement for the user plane part; - Traffic usage reporting; - an uplink classifier that supports routing of traffic flows to the data network; - Branching Point to support multi-homed PDU sessions; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Validation of uplink traffic (mapping of SDF to QoS flows); - Downlink packet buffering and downlink data notification triggering.

[0023] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Policy enforcement and QoS for the control plane; - Notification of downlink data.

[0024] <Procedures for RRC connection setup and reconfiguration> Figure 3 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE transitions from RRC_IDLE to RRC_CONNECTED (see TS 38.300).

[0025] RRC is a higher layer signaling (protocol) used for the configuration of the UE and the gNB. In particular, with this transition, the AMF prepares UE context data (which includes, for example, PDU session context, security keys, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding with a SecurityModeComplete message to the gNB. The gNB then performs reconfiguration to set up signaling radio bearer 2 (SRB2) and data radio bearer (DRB) by sending an RRCReconfiguration message to the UE and receiving an RRCReconfigurationComplete from the UE. For signaling-only connections, the steps related to RRCReconfiguration are omitted since SRB2 and DRB are not set up. Finally, the gNB informs the AMF that the setup procedure is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0026] Therefore, the present disclosure provides an entity (e.g., AMF, SMF, etc.) of a 5th Generation Core (5GC), comprising: a control circuit that operatively establishes a Next Generation (NG) connection with a gNodeB; and a transmitter that operatively transmits an initial context setup message to the gNodeB via the NG connection such that a signaling radio bearer between the gNodeB and a User Equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling including a resource allocation configuration information element (IE) to the UE via the signaling radio bearer. Then, the UE transmits in uplink or receives in downlink based on the resource allocation configuration.

[0027] <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, current and future research is also being conducted on the standardization of ultra-reliable low latency (URLLC) and multiple simultaneous connections. Figure 4 shows examples of usage scenarios that are expected for IMT beyond 2020 (see, for example, Figure 2 in ITU-R M.20183).

[0028] URLLC use cases have stringent performance requirements 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 38.913v16.0.0. 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.

[0029] From a physical layer perspective, reliability can be improved in many possible ways. Current room for reliability improvement includes defining a separate CQI table for URLLC, more compact DCI formats, repeated transmission of PDCCH, etc. However, this room can be expanded to achieve ultra-high reliability as NR (with respect to the key requirements of NR URLLC) becomes more stable and more developed. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0030] Also, technology extensions targeted by NR URLLC aim to improve latency and reliability. Technology extensions for improving latency include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configurable grant) uplink, repeated transmissions at slot level in data channel, and pre-emption in downlink. Pre-emption means that a transmission with already allocated resources is stopped and the already allocated resources are used for other transmissions with lower latency / higher priority requirements that are requested later. Thus, a transmission that was already allowed is preempted by a later transmission. Pre-emption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) can be preempted by a transmission of service type B (eMBB, etc.). Technology extensions for improving reliability include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0031] The mMTC (Massive Machine Type Communication) use case is characterized by a very large number of connected devices that typically transmit relatively small amounts of data that are not sensitive to latency. The devices are required to be low cost and have very long battery life. From an NR perspective, the use of very narrow bandwidth portions is one solution that saves power from the UE's perspective and allows for long battery life.

[0032] As mentioned above, it is expected that the scope of reliability improvement in NR will be broader. One of the key requirements for all cases, especially for URLLC and mMTC, is high or ultra-high reliability. Several mechanisms can be considered that can improve reliability from a radio perspective and a network perspective. In general, there are two to three key areas that can help improve reliability. These areas include compact control channel information, repeated transmission of data channel / control channel, and diversity with respect to frequency domain, time domain, and / or spatial domain. These areas are generally applicable to reliability improvement regardless of the specific communication scenario.

[0033] Further use cases with more stringent requirements are envisaged for NR URLLC, such as factory automation, transportation, and power distribution. The stringent requirements include high reliability (10 6 level of reliability), high availability, packet size up to 256 bytes, time synchronization up to a few μs (depending on the use case, the value can be 1 μs or a few μs depending on the frequency range and short latency on the order of 0.5 ms to 1 ms (in particular, a targeted latency of 0.5 ms on the user plane).

[0034] Furthermore, for NR URLLC, there can be several technical extensions from the perspective of the physical layer. These technical extensions include the extension of the PDCCH (Physical Downlink Control Channel) related to compact DCI, the repeated transmission of the PDCCH, and the increase in the monitoring of the PDCCH. Also, the extension of UCI (Uplink Control Information) is related to the extension of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. There can also be extensions of the PUSCH related to mini-slot level hopping, and extensions of retransmission / repeated transmission. The term "mini-slot" refers to a transmission time interval (TTI) that contains fewer symbols than a slot (a slot contains 14 symbols).

[0035] <QoS Control> The QoS (Quality of Service) model of 5G is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR (Granteed Bit Rate) QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest-grained QoS differentiation in a PDU session. A QoS flow is identified within a PDU session by a QoS flow ID (QFI: QoS Flow ID) that is carried in an encapsulation header via the NG-U interface.

[0036] 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 session, e.g. as shown above with reference to Fig. 3. Additional DRBs for the QoS flows of the PDU session can be configured later (when it is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. The NAS level packet filters in the UE and the 5GC associate UL and DL packets with QoS flows, whereas the AS level mapping rules in the UE and the NG-RAN associate UL and DL QoS flows with DRBs.

[0037] FIG. 5 shows a non-roaming reference architecture for 5G NR (see, for example, 3GPP TS 23.501 v16.9.0 or v16.7.1.1, section 4.2.3). An application function (AF), such as an external application server hosting a 5G service, as illustrated in FIG. 4, interacts with the 3GPP core network to provide the service. For example, it may access a network exposure function (NEF) to support applications that affect traffic routing, and interact with a 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 may 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 an external exposure framework via the NEF.

[0038] Figure 5 further illustrates further functional units of the 5G architecture, namely, Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator-provided services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and run in a cloud computing environment.

[0039] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, in operation, sends a request including QoS requirements for at least one of a URLLC service, an eMBB service, and an mMTC service to at least one of the 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.

[0040] <Bandwidth part> The NR system supports a maximum channel bandwidth (e.g., 100 MHz) that is much wider than the 20 MHz bandwidth of LTE. LTE also supports wideband communication via carrier aggregation (CA) of component carriers up to 20 MHz. Defining a wider channel bandwidth in NR allows for dynamic allocation of frequency resources via scheduling, which can be more efficient and flexible than the carrier aggregation operation of LTE, whose activation / deactivation is based on MAC control elements. Having a single wideband carrier also benefits in terms of lower control overhead, since only one control signaling is required (carrier aggregation requires separate control signaling for each aggregated carrier).

[0041] Also, like LTE, NR may support aggregation of multiple carriers via carrier aggregation or dual connectivity.

[0042] Since UEs do not always require high data rates, the use of wide bandwidths can lead to high idle power consumption in terms of both RF and baseband signal processing. In this regard, the newly developed bandwidth part concept for NR offers an energy-efficient solution despite supporting wideband operation by providing a means to operate UEs with bandwidths narrower than the configured channel bandwidth. Low-end terminals that cannot access the full NR bandwidth can benefit from it.

[0043] A bandwidth part (BWP) is a subset of the total cell bandwidth of a cell, e.g., defined by the location and number of contiguous physical resource blocks (PRBs). It may be defined separately for uplink and downlink. Furthermore, each bandwidth part may be associated with a specific OFDM numerology, e.g., subcarrier spacing and cyclic prefix. For example, bandwidth adaptation is achieved by configuring a BWP(s) in a UE and informing the UE which of the configured BWPs is currently active.

[0044] Exemplarily, in 5G NR, a specific BWP is configured only for a UE in the RRC_Connected state. For example, other than an initial BWP (e.g., one for UL and one for DL), BWPs exist only for UEs in the connected state. To support initial data exchange between the UE and the network, such as in the process of transitioning the UE from the RRC_IDLE or RRC_INACTIVE state to the RRC_CONNECTED state, the initial DL BWP and the initial UL BWP are configured with minimum system information.

[0045] Although a UE can be configured with more than one BWP (e.g., up to four BWPs per serving cell as currently defined in NR), a UE has only one active DL BWP at a time. Switching between configured BWPs can be achieved, for example, using downlink control information (DCI).

[0046] For a primary cell (PCell), the initial BWP is the BWP used for initial access, and the default BWP is the initial BWP unless another initial BWP is explicitly configured. For a secondary cell (SCell), the initial BWP is always explicitly configured and a default BWP may also be configured. If a default BWP is configured for the serving cell, the active BWP is switched to the default BWP when the inactivity timer associated with that cell expires.

[0047] Some DCI formats do not include a BWP ID (e.g., formats 0_0 and 1_0), while in other DCI formats the number of bits for the BWP ID is configurable by the RRC and can be 0, 1 or 2 bits (e.g., for formats 0_1, 0_2, 1_1, and 1_2).

[0048] Figure 6 shows a scenario in which three different BWPs are configured: BWP1 with a frequency bandwidth of 40 MHz and a subcarrier spacing of 15 kHz, BWP2 with a width of 10 MHz and a subcarrier spacing of 15 kHz, and BWP3 with a width of 20 MHz and a subcarrier spacing of 60 kHz.

[0049] <Control information - Search space set> PDCCH monitoring is performed by the UE to identify and receive information intended for the UE, such as control information and user traffic (eg, DCI on the PDCCH and user data on the PDSCH indicated by the PDCCH).

[0050] Downlink control information (which may be referred to, for example, as downlink control information DCI) has essentially the same purpose in 5G NR as DCI in LTE, i.e., it is a set of special control information that schedules a downlink data channel (such as PDSCH) or an uplink data channel (such as PUSCH). In 5G NR, there are several different predefined DCI formats (see TS38.212v16.6.0 section 7.3.1). An overview is given in the table below. [Table 1]

[0051] In 5G NR, the PDCCH is transmitted in a radio resource region called the control resource set (CORESET). In LTE, the concept of a CORESET does not explicitly exist. Instead, the LTE PDCCH uses the entire carrier bandwidth in the first 1-3 OFDM symbols (4 in the narrowest case). In contrast, the NR CORESET can be anywhere in the slot and anywhere in the frequency range of the carrier, except that a UE is not expected to handle a CORESET outside its active bandwidth part (BWP).

[0052] Thus, the UE performs a PDCCH monitoring operation, for example as defined in 3GPP TS38.213 version 16.6.0, sections 10 and 11. As exemplarily defined therein, the UE monitors a set of PDCCH candidates defined in units of PDCCH search space sets. The search space set can be a common search space set (CSS) or a UE-specific search space set (USS). As exemplarily defined in 3GPP TS38.213v16.6.0, section 10.1, the UE monitors PDCCH candidates in one or more of the following CSS sets and USS sets: - the Type0-PDCCH CSS set by pdcch-ConfigSIB1 in MIB, or searchSpaceSIB1 in PDCCH-ConfigCommon, or searchSpaceZero in PDCCH-ConfigCommon for a DCI format with CRC scrambled by SI-RNTI on the primary cell of the MCG; - Type0A-PDCCH CSS set by searchSpaceOtherSystemInformation in PDCCH-ConfigCommon for DCI format with CRC scrambled by SI-RNTI on the primary cell of the MCG - the Type1-PDCCH CSS set by ra-SearchSpace in PDCCH-ConfigCommon for DCI formats with CRC scrambled by RA-RNTI, MsgB-RNTI, or TC-RNTI on the primary cell; - Type2-PDCCH CSS set by pagingSearchSpace in PDCCH-ConfigCommon for DCI formats with CRC scrambled by P-RNTI on the primary cell of the MCG - the Type3-PDCCH CSS set by the SearchSpace in PDCCH-Config with SearchSpaceType=common for INT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI, or CI-RNTI, and for the primary cell only, for DCI formats with CRC scrambled by C-RNTI, MCS-C-RNTI, CS-RNTI(s), or PS-RNTI; - a USS set configured by a SearchSpace in a PDCCH-Config with SearchSpaceType=ue-Specific for a DCI format with CRC scrambled by a C-RNTI, MCS-C-RNTI, SP-CSI-RNTI, CS-RNTI(s), SL-RNTI, SL-CS-RNTI, or SL semi-persistent scheduling V-RNTI

[0053] The search space sets in one or more CORESETs on the active DL BWP in each activated serving cell configured for PDCCH monitoring using the corresponding search space set are monitored, where monitoring means decoding each PDCCH candidate according to the monitored DCI format.

[0054] The first CORESET, CORESET0, is provided as part of the initial bandwidth part configuration by the master information block (MIB), allowing to receive the remaining system information and additional configuration information from the network. After the connection is set up, multiple CORESETs can be configured in the UE using RRC signaling.

[0055] In an exemplary 5G NR implementation, a search space may include multiple PDCCH candidates associated with the same aggregation level (e.g., the PDCCH candidates differ in terms of the DCI format to be monitored). A search space set may then include multiple search spaces with different aggregation levels but associated with the same CORESET. As mentioned above, unlike LTE, where the control channel spans the entire carrier bandwidth, the bandwidth of the CORESET can be set, for example, within the active DL frequency bandwidth part (BWP). In other words, the CORESET configuration defines the frequency resources of the search space set and thus the PDCCH candidates included in the search spaces in that set. The CORESET configuration also defines the duration of the search space set, which can have a length of 1 to 3 OFDM symbols. Meanwhile, the start time is set by the search space set configuration itself, e.g., from an OFDM symbol of a certain slot, the UE starts monitoring the PDCCH of the search spaces of that set. The combination of the Search Space Set configuration and the CORESET configuration provides a clear definition in frequency and time domain for the UE's PDCCH monitoring requirements (see, for example, 3GPP TS38.213v16.6.0, section 10.1).

[0056] Conceptually, Figure 6 provides an exemplary diagram of the relationship between bandwidth parts, CORESETs, search spaces, search space sets, and PDCCH candidates that a UE can monitor. As is evident from Figure 6, one CORESET is shown per BWP, but more than one is possible. Each CORESET can then have several search spaces of one or more PDCCH candidates of a particular aggregation level (e.g., AL2, 4, or 8), which can be grouped into search space sets, e.g., common SS sets and UE-specific SS sets.

[0057] Both the configuration of CORESET and search space set can be done semi-statically via RRC signaling, and the corresponding RRC information elements are ControlResourceSet and SearchSpace, for example as defined in 3GPP TS38.331v16.5.0, provided below.

[0058] <Time domain in 5G NR> In the time domain, 5G NR transmissions are organized into frames of length 10 ms, each of which is divided into 10 equally sized subframes of length 1 ms. In turn, the subframes are divided into one or more slots, each of which consists of 14 OFDM symbols. The duration of the slots in milliseconds varies depending on the numerology. Thus, for example, for a subcarrier spacing of 15 kHz, an NR slot has the same structure as an LTE subframe with a normal cyclic prefix. The 5G NR subframe serves as a numerology-independent time reference, which is particularly useful when multiple numerologies are mixed on the same carrier, whereas the slot is the typical unit of dynamic scheduling. This frame structure, which is the basis of 3GPP 5G NR communication, is exemplarily shown in Figure 7.

[0059] <New frequency spectrum above 52GHz> 5G NR operates in two frequency ranges so far: FR1 and FR2. Frequency range 1 (FR1) is between 450 MHz and 6 GHz and includes LTE. Frequency range 2 (FR2) is between 24.25 GHz and 52.6 GHz. The sub-6 GHz range is designated FR1, and the mmWave spectrum is designated FR2.

[0060] The relatively underutilized millimeter-wave (mmWave) spectrum offers an excellent opportunity to provide high data rates, low latency, and high capacity due to the huge amount of contiguous bandwidth available. However, operation in bands with frequencies above 52.6 GHz is limited by device performance, such as poor power amplifier (PA) efficiency, higher phase noise impairments, increased front-end insertion loss, and noise in low noise amplifiers (LNAs) and analog-to-digital converters (ADCs). In addition, bands with frequencies above 52.6 GHz present challenges related to high propagation and penetration losses. Nevertheless, various use cases are envisioned for NR operating in the frequency range from 52.6 GHz to 114.25 GHz.

[0061] 3GPP is currently discussing the use of higher subcarrier spacing, such as 480 kHz and 960 kHz, for higher frequencies above 52.6 GHz, such as the 52.6 GHz to 71 GHz frequency range.

[0062] However, the higher the SCS, the shorter the symbol duration and, consequently, the shorter the slot duration. For example, for a 120 kHz SCS, one slot is 125 us, but for a 480 kHz SCS, one slot is 31.25 us, and for a 960 kHz SCS, it is 15.625 us.

[0063] Figure 8 shows a comparison of the slot length for the 120 kHz SCS with the corresponding slot lengths for the 480 kHz and 960 kHz SCSs. Furthermore, the radio frame has 32 slots for the 480 kHz SCS and 64 slots for the 960 kHz SCS, with 14 OFDM symbols per slot and correspondingly shorter OFDM symbol durations.

[0064] These shortened OFDM symbol and slot durations may require high processing power on the UE side. A UE following Rel.15 or Rel.16 should be able to process the PDCCH every slot (single slot monitoring capability). On the other hand, in the high frequency range of 52.6-71 GHz, all UEs may not be able to process each slot within such a short time. Furthermore, even if it were practically possible, the need for such a processing timeline would significantly increase the UE complexity and power consumption.

[0065] Therefore, for Rel.17, 3GPP is discussing the feasibility of allowing the UE to monitor the PDCCH only every multiple slots in the case of 480 / 960 kHz SCS, i.e. so-called multi-slot monitoring, in other words the UE does not need to monitor every slot.

[0066] <Multi-slot monitoring> 3GPP is currently discussing how to implement multi-slot monitoring functionality, particularly based on the following framework: Use a fixed slot group pattern to define the possibilities Each slot group consists of X slots ○ Slot groups are contiguous and non-overlapping The UE only needs to monitor Y consecutive slots in each slot group and can rest during the remaining XY slots. ○ For example, 3GGP is discussing using X=4 slots for SCS480kHz and X=8 slots for SCS960kHz. For example, 3GPP is discussing limiting Y to: 1≦Y≦X / 2. Regarding the multi-slot monitoring function, further relevant agreement has not yet been reached within 3GPP.

[0067] FIG. 9 shows how the slots are grouped into slot groups for the cases X=4 and X=8, respectively.

[0068] It is currently assumed that X is 4 or 8, however, it should be noted that X is not limited to these values ​​and other values ​​are also possible, e.g., 2, 3, 5, 6, 7, 9, etc.

[0069] <Further improvements> As presented above, one of the developments currently being discussed in 3GPP relates to multi-slot monitoring capabilities at high SCS and in the high frequency range, e.g. 52.6-71 GHz, which would allow for a reduction in UE complexity and power consumption. However, at present it is unclear how to determine the location of the Y slots within each slot group, in other words how to determine which slots within a slot group of X slots belong to Y and thus are to be monitored by the UE. Conceptually, two different schemes are possible: Method 1: The positions of the Y slots are always fixed, for example, the Y slots always start from the first slot in the slot group. · Scheme 2: The positions of the Y slots are variable, i.e., changed, e.g., the positions of the Y slots can be located anywhere within the slot group, and the positions can be changed, e.g., from slot group to slot group.

[0070] However, both approaches have drawbacks, as will be explained below.

[0071] According to scheme 1, the positions of the Y slots are fixed, so there is no flexibility as to which slot belongs to the Y slots, and thus no flexibility for the gNB to contact the UE. Also, it is not possible to change the Y slots midway, which further limits the flexibility of multi-slot monitoring and makes adaptation to traffic, etc. impossible. The drawbacks associated with the fixed scheme 1 are illustrated in the following example, which assumes that a Common Search Space (CSS) is transmitted via Time-Division Multiplexed (TDM) beams with beam sweeping. Figure 10 shows four different beams of beam sweep transmission from the gNB to two UEs, UE1 and UE2. Assume that UE1 is located in the area of ​​beam 1 and UE2 is located in the area of ​​beam 4. The time diagram on the right hand side of Figure 10 shows how the beam sweep transmissions are time division multiplexed, e.g. at different times.

[0072] FIG. 11 is based on the exemplary assumptions of FIG. 10 and illustrates reception of the CSS of each beam in different slots, for example, the CSS of beam 1 is received in slots 0, 4, 8 (etc.), the CSS of beam 2 is received in slots 1, 5, 9 (etc.), the CSS of beam 3 is received in slots 2, 6, 10 (etc.), and the CSS of beam 4 is received in slots 3, 7, 11 (etc.). Further illustratively, assume that X=4, each slot group includes 4 slots, and assume that Y=1, so that the UE monitors one slot in each slot group and the remaining three slots can be rested. In the exemplary scenario of FIG. 11, the relative positions of the Y slots are fixed to the first slot of each slot group, i.e., slots 0, 4, 8, .... It is further assumed that both UE1 and UE2 have the same fixed positions of the Y slots.

[0073] In such beam-sweeping transmission of CSS, UEs located in different beam directions may need to monitor different slots to receive CSS, UE1 needs to monitor in slot 0, UE2 needs to monitor in slot 3, etc. This may already contradict Scheme 1, which requires fixed positions of Y slots (for all UEs). Also, in this scenario, UE2 cannot receive CSS.

[0074] Moreover, even from the perspective of a single UE, Scheme 1 is disadvantageous. For example, the location of the UE may change, and thus the serving beam of the UE may also change. As a result, even if the UE is able to monitor the appropriate slots to receive the CSS of a beam at one point in time, the UE may change its location and beam and may not be able to receive the CSS via the new beam.

[0075] Overall, multi-slot monitoring using slot groups according to Scheme 1 appears to have significant drawbacks.

[0076] Conversely, according to the above Scheme 2, the positions of the Y slots can be changed, which may avoid the above drawbacks associated with Scheme 1. However, since the positions of the Y slots are not fixed, clear rules are needed to determine the positions of the Y slots at the UE and the gNB. However, such rules are currently missing. Without such rules, the gNB and the UE may have different understandings of the position of Y, which may result in the UE not being able to correctly receive the PDCCH transmitted by the gNB.

[0077] Having identified the potential drawbacks and challenges discussed above, the inventors have identified the possibility of providing an improved PDCCH (Downlink Control Channel) monitoring procedure that makes it possible to avoid or mitigate one or more of the above identified problems. The present invention relates to various solutions and variants for such an improved downlink control channel monitoring procedure, and more particularly to a method for determining the positions of the Y monitoring slots.

[0078] For example, the improved downlink control channel monitoring procedure makes it possible to avoid any misunderstanding as to which Y slots of a slot group can be used for exchanging a PDCCH.

[0079] <Embodiment> In the following, UEs, base stations, and respective procedures that meet these needs are described for new radio access technologies envisioned for 5G mobile communication systems, but which may also be used in previous LTE mobile communication systems or future mobile communication systems. Various implementations and variations are described as well. The following disclosure is facilitated by, and may be based, for example, at least in part on, the discussion and insights presented above.

[0080] In general, it should be noted that many assumptions have been made herein and will be made below in order to be able to explain the principles underlying the present disclosure in a clear, concise and understandable manner. However, these assumptions should be understood as merely examples made herein for the purpose of explanation and should not limit the scope of the present disclosure. Those skilled in the art will realize that the principles of the following disclosure and claims can be applied in different scenarios and in ways not explicitly described herein.

[0081] Furthermore, some of the terms such as procedures, entities, layers, etc. used below are closely related to those used in the LTE / LTE-A system or current 3GPP 5G standardization, but the specific terms used in the context of new radio access technologies for the upcoming 3GPP 5G communication system have not yet been fully determined or may eventually be changed. Thus, the terms may be changed in the future without affecting the functionality of the embodiments. As a result, those skilled in the art recognize that the embodiments and their scope of protection should not be limited to the specific terms used illustratively in this specification lacking newer terms or terms to be finally agreed upon, but should be more broadly understood by the functions and concepts underlying the functions and principles of the present disclosure.

[0082] For example, a mobile station or mobile node or user terminal or user equipment (UE) is a physical entity (physical node) in a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predefined set of functions to other functional entities of the same or another node or network. A node may have one or more interfaces that attach the node to a communication facility or medium that allows the node to communicate. Similarly, a network entity may have logical interfaces that attach a functional entity to a communication facility or medium that allows the node to communicate with other functional entities or corresponding nodes.

[0083] The term "base station" or "radio base station" in this specification refers to a physical entity in a communication network. Similar to a mobile station, a base station may have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predefined set of functions to other functional entities of the same or another node or network. A physical entity performs several control tasks for a communication device, including one or more of scheduling and configuration. Note that the base station functionality and the communication device functionality may be integrated in a single device. For example, a mobile terminal may also implement the base station functionality for other terminals. The term used in LTE is eNB (or eNodeB), while the term currently used for 5G NR is gNB.

[0084] Communications between a UE and a base station are typically standardized and may be defined by different layers, such as PHY, MAC, RRC, etc. (see background discussion above).

[0085] The expressions "monitoring opportunity", "downlink control channel monitoring opportunity", "PDCCH monitoring opportunity" and similar expressions should be broadly understood as, for example, a time period (e.g., a set of one or more consecutive symbols) of a time slot during which a UE is configured to monitor a corresponding downlink control channel (e.g., a PDCCH, e.g., according to a PDCCH candidate). For example, the UE determines a monitoring opportunity for each search space and search space set configured therefor. For example, the UE determines a MO (Monitoring Occasion) from both a search space set (e.g., information element SearchSpace) and a control resource set (e.g., information element ControlResourceSet).

[0086] The expression "search space set" can be broadly understood as a set of search spaces having multiple search spaces, each including one or more possible candidates for receiving a DCI message. For example, a search space is a grouping of various candidates having the same aggregation level but different formats of DCI messages. In turn, for example, a set of search spaces may include search spaces having different aggregation levels but associated with the same set of monitored time-frequency resources (e.g., the same CORESET). A specific exemplary implementation of a search space set is given by the 3GPP 5G NR standard, as described above.

[0087] The term “monitoring” may be broadly understood as a process of attempting to decode possible candidates for receiving a DCI message based on a particular format, etc. Such decoding attempts may also be referred to as blind decoding.

[0088] The term "monitoring candidates" may be broadly understood as specific candidates monitored by the UE within a monitoring opportunity. In a specific example implementation conforming to the 3GPP 5G NR standard, the "monitoring candidates" may be considered as "PDCCH candidates."

[0089] In the following solution, it is exemplarily assumed that the improved downlink control channel monitoring procedure can be conceptually based on the PDCCH monitoring already defined according to the 3GPP 4G or 5G standards, as explained above.

[0090] 12 shows a general, simplified, exemplary block diagram of a user equipment (also referred to as a communication device) and a scheduling device (here exemplarily assumed to be located in a base station such as an eLTE eNB (aka ng-eNB) or a gNB in ​​5G NR). The UE and the eNB / gNB communicate with each other via (wireless) physical channels using their respective transceivers.

[0091] The communication device may include a transceiver and a processing circuit. The transceiver may include a receiver and a transmitter and / or may function as a receiver and a transmitter. The processing circuit may be one or more hardware, such as, for example, one or more processors or any LSI. There is an input / output point (or node) between the transceiver and the processing circuit, through which the processing circuit can control the transceiver during operation, i.e., control the receiver and / or the transmitter to exchange receive / transmit data. The transceiver may include an RF (radio frequency) front, including one or more antennas, amplifiers, and RF modulators / demodulators, as a transmitter and receiver. The processing circuit may perform control tasks, such as, for example, controlling the transceiver to transmit user data and control data provided by the processing circuit and / or to receive user data and control data that are further processed by the processing circuit. In addition, the processing circuit may be responsible for performing other processes, such as, for example, judgment, decision, calculation, measurement, etc. The transmitter may be responsible for performing the process of transmission and other processes related thereto. The receiver may be responsible for performing the process of reception and other processes related thereto, such as monitoring the channel.

[0092] Various solutions for the improved downlink control channel monitoring procedure are described below. In this connection, an improved UE, an improved base station, and an improved integrated circuit that participate in the improved downlink control channel monitoring procedure are presented. A method corresponding to the UE operation and the base station operation is also provided. The integrated circuit corresponds to the UE and the base station and their respective operations.

[0093] Figure 13 illustrates a simplified exemplary UE structure according to one exemplary implementation of the improved downlink control channel monitoring procedure, which may be implemented based on the general UE structure described in connection with Figure 12. The various structural elements of the UE illustrated in this Figure 13 may be interconnected with each other, e.g., by corresponding input / output nodes (not shown), e.g., for exchanging control and user data and other signals. Although not illustrated for purposes of illustration, the UE may include further structural elements.

[0094] As can be seen from FIG. 13, the UE may include circuitry for determining a monitoring time slot based on first and second criteria, and downlink control channel monitoring circuitry.

[0095] Thus, in the present case, as will become apparent from the disclosure below, the receiver of the UE may be exemplarily configured to at least partially perform one or more of: receiving a configuration message for configuring a monitoring function in the UE, receiving a downlink control information message on a downlink control channel, etc.

[0096] Thus, in the present case, as will become apparent from the disclosure below, the processing circuitry of the UE may be exemplarily configured to at least partially perform one or more of: determining one or more monitoring time slots in a corresponding time slot group, taking into account different criteria for determining the monitoring time slots, monitoring a downlink control channel in the determined monitoring time slots, etc.

[0097] Thus, in the present case, as will become apparent from the disclosure below, the transmitter of the UE may be exemplarily configured to at least partially perform one or more of the following: transmit a capability indication to the base station including information regarding the number of monitoring time slots in a time slot group that the UE supports;

[0098] One exemplary procedure, disclosed in further greater detail below, is implemented by a UE that includes: A processing circuit in the UE determines, for two or more timeslot groups, one or more timeslots in the timeslot groups to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving downlink control information messages. The processing circuit determines the monitoring timeslots in the timeslot groups according to: A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; 4. Perform the procedure according to one or more of the following:

[0099] The processing circuitry then monitors the downlink control channel in the determined one or more monitor time slots of the time slot group.

[0100] A corresponding exemplary method is performed by a UE: determining, for two or more timeslot groups, one or more timeslots in the timeslot groups to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: monitoring a downlink control channel in the determined one or more monitoring time slots of the time slot group; Includes.

[0101] A sequence diagram corresponding to an exemplary UE operation along with the UE and UE method discussed above is shown in Figure 14. As is apparent from Figure 14, the UE determines, for a timeslot group, a monitoring time slot to be monitored by the UE according to a monitoring function. The determination is based on one or more criteria, including a first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space and a second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space. After the corresponding determination, the UE can monitor the downlink control channel at the determined monitoring time slot of the timeslot group.

[0102] The above improved UE behavior correspondingly implements the multi-slot monitoring function currently being discussed in 3GPP as Scheme 2. Correspondingly, the location of the monitoring time slot is flexible and depends on the monitoring opportunities configured for the common search space and the UE-specific search space.

[0103] Furthermore, designating a limited amount of monitoring slots within each timeslot group allows the UE to not monitor the downlink control channel in the remaining timeslots of each timeslot group, i.e., in the timeslots that are not monitoring timeslots.

[0104] By making the location of the monitoring time slots within each time slot group flexible, the improved UE operation avoids the drawbacks caused by fixed locations as described above in relation to Scheme 1, e.g., avoiding the inflexibility of the gNB to contact the UE, avoiding the inflexibility to adapt the monitoring time slots to traffic or new beams, and avoiding the inability of some UEs to even receive downlink control information messages.

[0105] Furthermore, the improved UE operation facilitates having the advantage that the location of the monitoring timeslots can be different between different UEs, so that the gNB is more flexible in transmitting control information on different downlink resources to some UEs. Furthermore, when changing beams including monitoring opportunities, the UE can perform new decisions to adapt the monitoring timeslots to new situations.

[0106] Furthermore, defining an explicit UE behavior for determining the location of the monitoring time slot within the time slot group facilitates the base station and the UE to have the same understanding of the Y monitoring time slots, thereby facilitating UE operation to correctly receive downlink transmissions from the base station.

[0107] It has been described that the UE performs the monitoring timeslot determination according to two criteria such that the determined monitoring timeslot includes a monitoring opportunity associated with a CSS or a USS. Thus, this UE operation requires that the determination selects monitoring timeslots having a CSS and / or a USS until the UE reaches the maximum number of monitoring timeslots available for the timeslot group.

[0108] Some example implementations of the improved downlink control channel monitoring procedure also involve the base station to which the UE is currently connected (e.g., referred to as the serving base station because the base station serves the UE). Correspondingly, the improved downlink control channel monitoring procedure also provides for improved base stations to participate therein.

[0109] Fig. 15 shows a simplified exemplary base station structure according to one exemplary implementation of the improved downlink control channel monitoring procedure, which may be implemented based on the general base station structure described in relation to Fig. 12. The various structural elements of the base station shown in this Fig. 15 may be interconnected with each other, e.g., by corresponding input / output nodes (not shown), e.g., for exchanging control and user data and other signals. Although not shown for illustrative purposes, the base station may include further structural elements.

[0110] As is apparent from FIG. 15, the base station comprises a circuit for determining a monitoring time slot based on first and second criteria, and a downlink control information transmitter.

[0111] One exemplary procedure, disclosed in further more detail below, is implemented by a base station including: a processing circuit in the base station determines, for two or more timeslot groups, one or more timeslots in the timeslot group to be monitored by the user equipment UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving downlink control information messages transmitted from the base station; A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; 4. Perform the procedure according to one or more of the following:

[0112] A transmitter of the base station transmits a downlink control information message to the UE on a downlink control channel in at least one of the determined one or more monitor time slots of the time slot group.

[0113] The corresponding method is performed by a base station, determining, for two or more timeslot groups, one or more timeslots in the timeslot group to be monitored by the user equipment UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message transmitted from a base station; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: transmitting a downlink control information message to the UE on a downlink control channel in at least one of the determined one or more monitoring time slots of the time slot group; Includes.

[0114] A sequence diagram corresponding to an exemplary base station operation in accordance with the base station and corresponding method discussed above is shown in FIG. 16. The sequence diagram illustrates an exemplary simplified implementation of the base station method presented above. As is evident from FIG. 16, the base station determines a monitoring time slot for a time slot group based on one or more of a first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space and a second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space. The base station then transmits a downlink control information message to the UE on a downlink control channel in at least one of the determined monitoring time slots of the time slot group.

[0115] FIG. 17 illustrates a simplified exemplary interaction between the improved UE and the improved base station (here, for example, a gNB) of the improved downlink control channel monitoring procedure discussed above. In this solution illustrated in FIG. 17, this interaction includes corresponding determination of monitoring time slots in a timeslot group by the UE and the base station to facilitate a common understanding of the monitoring time slots for subsequent reception and transmission of downlink control information between the UE and the base station. In other words, the process of determining the monitoring time slots for each timeslot group can be exactly the same on the UE side and the gNB side, but other processes of the improved downlink control channel monitoring procedure can be different between the UE and the BS.

[0116] The UE may then start monitoring the downlink control channel based on the thus determined monitoring time slot, thereby enabling the UE to receive downlink control information from the gNB. Meanwhile, the base station eventually has downlink control information available to the UE and subsequently transmits the available downlink control information in one of the determined monitoring time slots. In response, the UE can receive downlink control information from the base station based on monitoring the determined monitoring time slot.

[0117] The improved downlink control channel monitoring procedure described above is based on the use of a first and a second criterion. According to an exemplary embodiment thereof, when determining a monitoring time slot in a time slot group, the first criterion regarding a common search space is considered before the second criterion regarding a UE-specific search space. Correspondingly, the common search space has priority over the UE-specific search space for inclusion in the monitoring time slot, which facilitates the UE not missing important control information broadcasted by the base station in the common search space.

[0118] According to one example along these lines, for Y monitoring timeslots in a timeslot group, the UE first determines which timeslots of the timeslot group include monitoring opportunities for a common search space and determines those timeslots as the monitoring timeslots of the timeslot group, then the UE determines which timeslots of the timeslot group include monitoring opportunities for a UE-specific search space and determines those timeslots as the monitoring timeslots of the timeslot group. These steps are performed by the UE until the number Y of monitoring timeslots is reached.

[0119] Additionally or alternatively, further priority levels may be implemented in the improved downlink control channel monitoring procedure described above, particularly with respect to UE-specific search spaces. Assume that UE-specific search spaces are associated with different priorities and are considered to be included in the monitoring timeslot in the order of their priorities. In one option, the priority of the UE-specific search space is indicated by the index of the UE-specific search space, and the lower the index of the UE-specific search space, the higher the priority it has for being included in the monitoring timeslot. The advantage of such prioritization of USSs may be that in the case where not all configured USSs can be included in the monitoring timeslot (e.g., due to UE capabilities for value Y), both the UE and the gNB know which USSs can be included and which are discarded.

[0120] Alternatively, the priority of the UE-specific search space is expressed by its distance (in the time domain) from the common search space: the closer the MO of the UE-specific search space is to the MO of the common search space, the higher the priority.

[0121] According to another variant, the determination of the monitoring time slot does not consider all common search spaces, but only a reduced set of common search spaces of the downlink control channel, in particular, the determination can distinguish between different common search spaces that can be configured for the UE.

[0122] In one example, the reduced set of common search spaces includes common search spaces configured in a dedicated message to the UE and / or common search spaces configured for a group of UEs. Correspondingly, the reduced set of CSSs includes common search spaces configured for a UE or a specific group of UEs, but not necessarily configured for all UEs (served by a cell of the gNB). In a 3GPP 5G compliant implementation, the reduced set of CSSs may include Type-1 CSSs configured by a dedicated message (e.g., RRC) to the UE, and Type-3 CSSs (see the description of the various types of CSSs above for details). The Type3-PDCCH common search space is a group common search space (i.e., a common search space assigned to a group of UEs, e.g., not necessarily assigned to all UEs).

[0123] Using such a reduced set of CSSs facilitates flexible placement of the Y monitoring time slots, since the CSSs considered for determining the monitoring time slots are UE-specific or UE group-specific. From the perspective of a base station serving many UEs, the positions of the Y monitoring time slots will be more variable, since the reduced set of CSSs is used for the determination. In other words, since both the reduced set of CSSs and the USS are UE-specific (or UE group-specific), the positions of the Y monitoring time slots are more likely to be different for each UE (or group of UEs). This increases the scheduling flexibility at the base station, since different time resources defined by the monitoring time slots can be used to transmit downlink control information to different UEs.

[0124] Meanwhile, the UE will not be able to receive the remaining CSSs, i.e., the CSSs that are not included in the reduced set of CSSs, e.g., in the above example, the Type1-PDCCH common search space, Type0, Type0A, and Type2 common search spaces that were not configured in the dedicated RRC message. To avoid this, in another example, a further monitoring opportunity is defined for the UE in the timeslot group other than the Y monitoring timeslots for the UE to monitor one or more or all of the remaining CSSs. Correspondingly, the further monitoring opportunity may be defined by the location of the remaining CSSs (and its monitoring opportunity) that is configured for the UE to be additionally monitored by the UE, e.g., a timeslot in the timeslot group that includes one or more of the remaining CSSs. Conversely, the BS may transmit the remaining CSSs in the further monitoring opportunity in the timeslot group other than the Y monitoring timeslots that is defined by the corresponding monitoring opportunity of the remaining CSSs.

[0125] In another converse example, this reduced set of common search spaces includes only common search spaces received by all UEs (served by the gNB's cells), e.g., one or more of the Type1-PDCCH common search space, Type0, Type0A, and Type2 common search spaces that were not configured in a dedicated RRC message. In this way, it is possible to align the Y positions of all UEs. From the perspective of the scheduling node (e.g., gNB), using the same Y position for all UEs reduces scheduling flexibility, but it also reduces scheduling complexity as well, since the gNB does not need to keep track of the Y positions of various UEs for scheduling, compared to the case where different UEs have different Y positions.

[0126] There may be cases where there is no CSS or USS for a monitoring timeslot, and the UE cannot determine a monitoring timeslot that includes a CSS or USS. In such a case, the UE may determine a further suitable timeslot as a "nominal" monitoring timeslot (but there is no MO in it), and the UE may not need to monitor the MO in the "nominal" monitoring timeslot. Alternatively, there may be no further MO to be monitored by the UE, so no further monitoring timeslot may need to be defined. In this case, the number of monitoring slots in the timeslot group is less than Y.

[0127] The above improved downlink control channel monitoring procedure, and associated UE, base station, includes determining a monitoring time slot of a time slot group.

[0128] Various solutions of the improved downlink control channel monitoring procedure described above are presented below on how to implement the step of determining the monitoring time slots, as shown in Figure 14 for the UE side and in Figure 16 for the base station side. Correspondingly, specific details provided in the first and second solutions below are applicable to both the UE and the BS, regardless of whether the description is presented from the perspective of only one entity, be it the UE or the BS.

[0129] In overview, the first solution is based on the idea that the determination of the monitoring time slot is performed for each time slot group individually, e.g., for each time slot group, the monitoring time slot is determined based on the monitoring opportunity of that time slot group.

[0130] Conversely, the second solution is based on the concept that the monitoring time slot determination is performed for multiple time slot groups jointly, e.g., the monitoring time slot determination is performed once taking into account the monitoring opportunities of multiple time slot groups, and the resulting common relative position of the monitoring time slot within the time slot group is commonly applied to each of the multiple time slot groups.

[0131] Before describing the first and second solutions in detail, exemplary assumptions are presented that serve as the basis for describing the first and second solutions. The following assumptions are provided primarily to facilitate the description of the various solutions, but the various solutions may also be implemented without these assumptions or using different underlying assumptions. As mentioned above, multi-slot monitoring is currently discussed, which includes the use of time slot groups, where the time slot groups are contiguous in time and non-overlapping, and each includes X number of time slots. In the following description, it is illustratively assumed that the time slot groups include four time slots. Similarly, it is illustratively assumed that the number Y of monitoring time slots in a time slot group is 1 or 2 slots.

[0132] Furthermore, the process of determining the monitoring time slots of each time slot group can be exactly the same on the UE side and the gNB side. Other processes of the improved downlink control channel monitoring procedure can differ between the UE and the BS, such as, for example, the monitoring of downlink control messages on the UE side and the corresponding transmission of downlink control messages on the BS side (see also FIG. 17).

[0133] <First Solution> In a first solution of the improved downlink control channel monitoring procedure, the determination of the monitoring time slot is performed for each time slot group individually, e.g., for each time slot group, the monitoring time slot is determined based on the monitoring opportunity of that time slot group.

[0134] 18 shows a flow diagram of an exemplary UE operation according to this first solution of the improved downlink control channel monitoring procedure. In the illustrated UE operation, it is assumed that a first criterion regarding a common search space is considered before a second criterion regarding a UE-specific search space. It is further exemplarily assumed that in the second criterion, the USSs are considered in ascending order of USS index.

[0135] The first illustrated step of UE operation shows that monitoring opportunities for the CSS and USS downlink control channels (eg, PDCCH) are configured in the UE.

[0136] Then, to be able to perform the monitoring function, the UE determines the monitoring timeslots for each timeslot group. In this first solution, this step is performed separately for each timeslot group. Correspondingly, the UE processes the current timeslot group and for the determination of the monitoring timeslots, first uses the first CSS-based criterion and then the second USS-based criterion. If no CSS is present in the current timeslot group, the UE proceeds to determine the monitoring timeslots including the USS.

[0137] Although not shown in Figure 18, the UE performs two decision steps until two monitoring slots are determined (considering the above exemplary assumption of Y=2). The result of the two decision steps is two monitoring timeslots that include CSS MO and / or USS MO.

[0138] There may be cases where there is no CSS or USS for a monitoring timeslot and the UE cannot determine a monitoring timeslot that includes a CSS or USS In such a case, the UE may not determine any further monitoring timeslots because there are no further MOs to be monitored by the UE.

[0139] Alternatively, the UE may determine the remaining "nominal" monitoring timeslot(s) in the timeslot group (which does not include CSS or USS), but based on another criterion, which may also be made explicit such that the corresponding decision on the gNB side results in the same monitoring timeslots. In one example, the UE may select the timeslot with the lowest (or highest) possible slot index in the current timeslot group (but satisfying all other constraints, e.g., that the monitoring timeslots are consecutive, etc.).

[0140] In another example, the UE may select a timeslot with the lowest (or highest) possible slot index in the current timeslot group (but satisfying all other constraints, such as that the monitoring timeslots are consecutive), but with the additional constraint that the selected timeslot is not a timeslot at a timeslot group boundary. In this example, such a decision helps to avoid a back-to-back problem where consecutive monitoring timeslots straddle a timeslot group boundary.

[0141] In yet another example, even if a timeslot group includes both CSS and USS, the monitoring timeslots of each timeslot group are determined based only on the first CSS-based criteria. The scheduling node, for example, gNB, can ensure by configuration that the number of slots including CSS in the timeslot group is equal to or less than the number Y. If the number of slots including CSS in the timeslot group is equal to the number Y, the monitoring timeslots are determined entirely by the first CSS-based criteria. On the other hand, if the number of slots including CSS in the timeslot group is less than the number Y, the above method for avoiding ambiguity can be further applied (but independent of USS). For example, the monitoring slots are selected from consecutive lowest possible slot indexes. The advantage of this example is that since the monitoring timeslots are no longer dependent on the USS, it becomes possible to align the Y position for a group of UEs (if not all UEs). In this way, the scheduling complexity is reduced, since the scheduling possibilities in time are restricted to a small set of timeslots (at the expense of some flexibility).

[0142] Another constraint or restriction that may need to be taken into account for determining the monitoring timeslots relates to whether the monitoring timeslots of a timeslot group need to be consecutive with each other. The outcome of the determination may vary greatly depending on whether the monitoring timeslots need to be consecutive. Allowing non-consecutive monitoring timeslots within a timeslot group increases the flexibility of the determination, which facilitates the resulting monitoring timeslots to include as many CSSs and / or USSs as possible. As a result, this facilitates that the gNB can use different radio resources to contact the UE.

[0143] On the one hand, having consecutive monitoring timeslots is beneficial for UE power saving because the UE can go to sleep state after monitoring consecutive monitoring timeslots to reduce power consumption, whereas if the monitoring timeslots are discontinuous, when the UE wants to sleep during a non-monitoring timeslot, the UE needs to power up and down many times, which increases power consumption.

[0144] The UE can then monitor the downlink control channel in the thus determined monitoring timeslots of the current timeslot group. Conversely, since the gNB is aware of the monitoring timeslots monitored by the UE, it can use them to transmit downlink control information to the UE.

[0145] The UE then proceeds to process the next group of timeslots and performs the above-mentioned decision steps again based on the first CSS-related criterion and the second USS-related criterion, respectively.

[0146] The UE operation of Figure 18 described above applies to various scenarios shown in Figures 19, 20, 21 and 22. Although this description is mainly related to how the UE performs the monitoring time slot determination, this description is equally applicable to the base station side monitoring time slot determination.

[0147] FIG. 19 shows the configuration of the UE's CSS and two USSs (USS#1 and USS#2).

[0148] In line with the UE operation of the first solution illustrated in FIG. 18, the UE (and gNB) determines that in the first slot group, timeslots 0 and 1 are the two monitoring timeslots. Specifically, considering the first CSS-related criterion, the UE may first determine that slot 0 is the monitoring timeslot because slot 0 includes a CSS MO. Then, since there is no more CSS MO in the other timeslots of that first timeslot group, the UE may then consider the second USS-related criterion and determine that slot 1 is the second monitoring timeslot because the USS with the lowest index is included in slot 1. Since the number Y of monitoring timeslots is 2, the UE cannot determine the other monitoring timeslots, so the UE cannot monitor USS#2 in timeslot 2. Thus, the relative positions of the monitoring timeslots of the first timeslot group include the first and second timeslots.

[0149] For the second timeslot group, independent determination of monitoring timeslots is performed by the UE and the gNB. Since there is no CSS in the second timeslot group, the UE subsequently determines that the first monitoring timeslot is slot 5, which has the MO of USS#1, which has a lower index. The second monitoring timeslot is determined to be slot 6, which includes the MO of USS#2. Thus, the relative positions of the monitoring timeslots in the second timeslot group include the second and third timeslots.

[0150] In the third and fifth timeslot groups, the UE and gNB determine the same relative positions of the monitoring timeslots as in the first timeslot group, because the distribution of CSS and USS will be the same for each period. As a result, in the third timeslot group, the monitoring timeslots will be slots 8 and 9, and in the fifth timeslot group, the monitoring timeslots will be slots 16 and 17, i.e., the first and second timeslots, respectively.

[0151] In the fourth timeslot group, the UE and the gNB determine the same relative positions of the monitoring timeslots as in the second timeslot group, because the distribution of CSS and USS will be the same for each period. As a result, in the fourth timeslot group, the monitoring timeslots will be slots 13 and 14, i.e., the second and third timeslots.

[0152] As is evident from the exemplary scenario of FIG. 19, the Y monitoring timeslots in each timeslot group may be changed from one timeslot group to another. Specifically, in the second timeslot group, the monitoring timeslots are shifted by one timeslot compared to the first timeslot group, since there is no CSS MO in the first slot and there is a USS MO in the third timeslot. This flexibility of decision allows the UE to monitor the USS#2 monitoring opportunity (and can be used for DCI transmission by the gNB) in at least some timeslot groups (here every other timeslot group). Moreover, the monitoring timeslots are still determined to include CSS when possible.

[0153] Figure 20 shows the configuration of the UE's CSS and two USSs (USS#1 and USS#2) according to another scenario. It is exemplarily assumed that the CSS first occurs in slot 0 and occurs with a period of 7 slots, USS#1 first occurs in slot 1 and occurs with a period of 4 slots, and USS#2 first occurs in slot 2 and occurs with a period of 4 slots. At the bottom of Figure 20, the resulting Y=2 monitoring time slots per time slot group are shown. Correspondingly, the main difference in the assumptions compared to the scenario of Figure 19 is the different period of the CSS.

[0154] In line with the UE operation of the first solution illustrated in FIG. 18, the UE (and gNB) determines that in the first slot group, timeslots 0 and 1 will be the two monitoring timeslots, similar to that described in FIG. 19. Meanwhile, in the second timeslot group, the distribution of CSS and USS is different, and the resulting monitoring timeslots are also different. Specifically, considering the first CSS-related criteria, the UE may first determine that slot 7 will be the monitoring timeslot, since slot 7 includes a CSS MO. Then, considering the second USS-related criteria, the UE may then determine that slot 6 will be the second monitoring timeslot, since there is no more CSS MO in the other timeslots of that second timeslot group. Although slot 5 includes the MO of USS#1, slot 5 cannot be selected as the monitoring timeslot, since slot 5 is not adjacent (i.e., not consecutive) to the first monitoring timeslot 7. Thus, timeslot 6, which includes the MO of USS#2, is selected as the second consecutive monitoring timeslot in the second timeslot group. In general, the monitoring time slots are consecutive time slots 6 and 7 of the second time slot group.

[0155] In the third timeslot group, the determination results in consecutive monitoring timeslots 9 and 10. Since there is no CSS in that third timeslot group, the UE subsequently determines that the first monitoring timeslot is slot 9, which has the MO of USS#1, which has a lower index. The second monitoring timeslot is determined to be slot 10, which contains the MO of USS#2.

[0156] In the fourth time slot group, the determination results in consecutive monitoring time slots 13 and 14. Specifically, considering the first CSS-related criterion, the UE may first determine that slot 14 will be the monitoring time slot because slot 14 includes a CSS MO, and in this scenario, slot 14 also includes an MO of USS#2. Then, since there are no more CSS MOs in the other time slots in that fourth time slot group, the UE may then consider the second USS-related criterion and determine that slot 13 will be the second monitoring time slot because slot 13 includes an MO of USS#1.

[0157] FIG. 21 shows the configuration of the UE's CSS and two USSs (USS#1 and USS#2) according to the same scenario as in FIG. 20. Thus, it is exemplarily assumed that the CSS first occurs in slot 0 and occurs with a period of 7 slots, USS#1 first occurs in slot 1 and occurs with a period of 4 slots, and USS#2 first occurs in slot 2 and occurs with a period of 4 slots. At the bottom of FIG. 21, the resulting Y=2 monitoring time slots per time slot group are shown. However, the main difference is that the monitoring time slots do not have to be consecutive. In other words, there is no additional constraint during the determination of the monitoring time slots that requires the resulting monitoring time slots to be consecutive.

[0158] As a result of the determination, the same monitoring timeslots are obtained in the first, third, fourth, and fifth timeslot groups (see FIG. 20), but in the second timeslot group, the UE and the gNB determine discontinuous monitoring timeslots 5 and 7. Specifically, with respect to FIG. 20, considering the first CSS-related criteria, the UE may first determine that slot 7 will be the monitoring timeslot, since slot 7 includes a CSS MO. Then, since there is no more CSS MO in the other timeslots of that second timeslot group, the UE may determine by considering the second USS-related criteria. In this case, since discontinuous monitoring timeslots are allowed, the UE may determine the second monitoring timeslot to be slot 5, which includes the MO of USS#1.

[0159] Figure 22 shows the configuration of CSS and USS for two different UEs, i.e., UE1 and UE2. Specifically, it is exemplarily assumed that the CSS for both UEs occurs first in slot 0 and occurs with a period of 6 slots, the USS for UE1 occurs first in slot 1 and occurs with a period of 4 slots, and the USS for UE2 occurs first in slot 3 and occurs with a period of 4 slots. Then, Figure 22 shows the resulting Y=2 consecutive monitoring time slots for UE1 under UE1 USS MO, and shows the resulting Y=2 consecutive monitoring time slots for UE2 under UE2 USS MO.

[0160] In the first timeslot group, in line with the UE operation of the first solution illustrated in Figure 18, UE1 (and gNB) determines that slots 0 and 1 will be the two monitoring timeslots. The two monitoring timeslots include the CSS MO and UE1's USS MO.

[0161] Next, UE2 and gNB determine that slots 0 and 1 will be the two monitoring timeslots. Here, UE2 first determines slot 0 to be the monitoring timeslot because slot 0 contains a CSS MO. Then, using the second USS-related criteria, UE2 cannot select slot 3 as the second monitoring timeslot because slot 3 is not contiguous with the previously determined first monitoring timeslot 0. Instead, slot 1 is selected as the second monitoring timeslot because it is contiguous with the previously selected slot 0 that contains a CSS MO. Thus, slot 1 can be defined as UE2's "nominal" monitoring timeslot. However, since slot 1 does not contain a CSS or USS MO, UE2 may not actually need to monitor in slot 1 of the first timeslot group because there is no MO configured to monitor.

[0162] Alternatively (as shown in FIG. 22), UE2 may not select a second monitoring timeslot in its first timeslot group at all, since slot 1 does not contain a CSS or USS MO. The UE has the opportunity to save power in slot 1.

[0163] Overall, UE1 and UE2 happen to have the same monitoring time slot in the first time slot group.

[0164] However, in the second timeslot group, the resulting monitoring timeslots of UE1 and UE2 are different: specifically, UE1 and the gNB determine monitoring timeslots 5 and 6 for UE1, and UE2 and the gNB determine monitoring timeslots 6 and 7 for UE2 according to the first and second criteria, respectively.

[0165] In the third timeslot group, the resulting monitoring timeslots of UE1 and UE2 are also different. UE1 and gNB determine slot 9 to be the first monitoring timeslot since slot 9 contains a USS MO (and there is no CSS in the third timeslot group). As second monitoring timeslots, timeslots 8 and 10 are consecutive to the previously selected first monitoring timeslot 9, but both do not contain a CSS or USS MO. According to one exemplary implementation (not shown in FIG. 22), UE1 and gNB determine slot 8 as the second monitoring timeslot since slot 8 is the timeslot with the lowest (lower) slot index. Alternatively, no further monitoring timeslot is selected for UE1, so that in the third timeslot group, there is only monitoring timeslot 9 for UE1. These two actions ultimately result in the same result, since gNB does not transmit DCI using slot 8 for UE1.

[0166] Correspondingly, for UE2, in FIG. 22 it is illustratively assumed that UE2 and the gNB determine only slot 11 to be the monitoring timeslot.

[0167] In the fourth timeslot group, the resulting monitoring timeslots for UE1 and UE2 are timeslots 12 and 13, ie, in the same relative positions as the monitoring timeslots in the first timeslot group.

[0168] In the fifth timeslot group, similar to the second timeslot group already described above, the resulting monitoring timeslots for UE1 and UE2 are also different.

[0169] As is evident from Figure 22, different UEs may monitor the downlink control channel in different monitoring time slots according to the respective distribution of CSS and USS in different time slot groups, thus increasing the flexibility of the gNB to transmit information to the UEs.

[0170] In a further implementation, the first solution of the improved downlink control channel monitoring procedure may also use a different first criterion, i.e., that the monitoring time slot includes a monitoring opportunity associated with a common search space of the reduced set of CSSs. This has already been described in detail above with respect to the improved downlink control channel monitoring procedure in relation to Figures 14 to 17 and is equally applicable to the first solution. In summary, the reduced set of CSSs may include CSSs that are not necessarily configured for all UEs, such as Type-1 CSSs and Type-3 CSSs that are configured by a dedicated message to the UE. The remaining CSSs that are not included in the reduced set of CSSs (CSSs that are commonly configured for all UEs, such as Type-1 CSSs, Type-0 CSSs, Type-0A CSSs, and Type-2 CSSs that are not configured by a dedicated message) may be exemplarily monitored by the UE in further monitoring opportunities in the time slot group other than the Y monitoring time slots. Conversely, the BS may transmit the remaining CSSs in further monitoring opportunities in the time slot group other than the Y monitoring time slots that are defined by the corresponding monitoring opportunities of the remaining CSSs.

[0171] A corresponding exemplary scenario is shown in Figure 23, where we assume two different types of CSS: Type-0 CSS with MO in slot 2 and occurring with a period of 4 slots, and Type-3 CSS with MO in slot 1 and occurring with a period of 8 slots. Furthermore, we exemplarily assume that the UE has one USS with MO in slot 0 and occurring with a period of 4 slots.

[0172] With the assumed distribution of CSSs and USSs, the UE and gNB determine that within the first timeslot group, the first monitoring timeslot is timeslot 1, which includes a Type-3 CSS from the reduced set of CSSs of the first criterion. Meanwhile, the UE does not consider timeslot 2 as part of the Y monitoring timeslots because the included MO belongs to a Type-0 CSS that is not included in the reduced set of CSSs of the first criterion. Rather, the UE determines slot 0 as the second monitoring timeslot according to the second USS-related criterion.

[0173] However, in one example implementation, as shown in FIG. 23, the remaining Type-0 CSS MO in slot 2 of the first time slot group, albeit outside the Y monitoring slots, can still be monitored by the UE (if the UE is capable of doing so) (see “UE monitors CSS MO” in each third slot of each slot group).

[0174] In the second timeslot group, the UE and gNB determine the monitoring slots to be timeslots 4 and 5. Specifically, since there is no MO of the CSS of the reduced set of CSSs of the first criterion, the UE proceeds to determine the monitoring timeslots according to the second USS-related criterion and determines timeslot 4 as the first monitoring timeslot. Timeslot 5 can then be determined as the second of the two monitoring timeslots since it is the only timeslot consecutive to the previously determined monitoring timeslot 4, or no further monitoring timeslots are determined. Again, in one exemplary implementation, the UE can monitor the remaining Type-0 CSS MO of slot 6, albeit outside of the Y monitoring slots, as shown in FIG. 23.

[0175] The UE and gNB decisions regarding the third and fifth slot groups correspond to those described above for the first slot group, and the UE and gNB decisions regarding the fourth slot group correspond to those described above for the second slot group.

[0176] In another converse example, this reduced set of common search spaces includes only the common search spaces received by all UEs (served by the gNB's cells), e.g., the Type1-PDCCH common search space, the Type0, Type0A, and Type2 common search spaces that were not configured in a dedicated RRC message, as already described before going into the first solution.

[0177] The above first solution and its variants and implementations have been described mainly from the UE's perspective, however, the above monitoring slot determination can be performed in exactly the same way in the UE and the BS, so the above first solution and its variants and implementations are also applicable to the base station side.

[0178] The BS and UE differ in how the resulting monitoring timeslots are used in further processing: the UE uses the monitoring timeslots for monitoring functions (see Figure 14) and the BS uses the monitoring timeslots for transmitting downlink control information (see Figure 16).

[0179] <Second solution> A second solution for the improved downlink control channel monitoring procedure is based on the concept that the monitoring time slot determination is performed for multiple time slot groups jointly, e.g., the monitoring time slot determination is performed once taking into account monitoring opportunities for multiple time slot groups, and the resulting common relative position of the monitoring time slot within the time slot group is commonly applied to each of the multiple time slot groups.

[0180] FIG. 24 shows a flow chart of an exemplary UE operation according to this second solution of the improved downlink control channel monitoring procedure, which is based on similar assumptions as the UE operation described in connection with FIG. 18. For example, the illustrated UE operation again assumes that a first criterion regarding a common search space is considered before a second criterion regarding a UE-specific search space. Furthermore, it is exemplarily assumed that in the second criterion, the USSs are considered in ascending order of USS index. The UE is configured with monitoring opportunities for the CSS and the downlink control channel (e.g., PDCCH). Then, to be able to perform the monitoring function, the UE determines the monitoring time slots for each time slot group.

[0181] However, instead of performing the decision process for each timeslot group separately as in the first solution, the decision step according to the second solution is performed for multiple timeslot groups together. Specifically, the UE and gNB determine the optimal location of the monitoring timeslot(s) (i.e., one or more monitoring timeslots) within a timeslot group for multiple timeslot groups, rather than for a single timeslot group. Accordingly, the UE and gNB perform the decision based on several timeslot groups and the distribution of CSS and USS MOs therein, rather than based on a single timeslot group alone.

[0182] According to this second solution, the UE and gNB determine a common relative position of one or more monitoring time slots in a time slot group that strives to meet a first CSS-related criterion (e.g., the monitoring time slot shall include an MO of the CSS, if possible) across several time slot groups. For example, the UE and gNB may first consider several time slot groups, specifically, which time slots include an MO of the CSS, and then determine the relative position of the time slot including the CSS MO as the monitoring time slot (even if, in some time slot groups, the time slot at that relative position does not include a CSS MO). This determined relative position thus corresponds to the first monitoring time slot. If two or more MOs of different CSSs are available, the UE may consider determining a further different relative position in the time slot group as corresponding to the second monitoring time slot, and so on.

[0183] Then, if further monitoring timeslots need to be determined (e.g., after applying the first criterion, the number Y of monitoring timeslots has not yet been reached), the UE and gNB may subsequently determine a common relative position of one or more monitoring timeslots within a timeslot group that strives to meet the second USS-related criterion (e.g., the monitoring timeslots shall include the MO of the USS, optionally in ascending order of USS index) across several timeslot groups. For example, the UE and gNB may first consider several timeslot groups, specifically, which timeslots include the MO of the USS, and then determine the relative position of the timeslot including the USS MO as the monitoring timeslot (even if, in some timeslot groups, the timeslot at that relative position does not include the USS MO). This determined relative position thus corresponds to the other monitoring timeslot in addition to the one previously determined based on the first criterion. If two or more MOs of different USSs are available, the UE may consider determining further different relative positions within the timeslot group as corresponding to yet other monitoring timeslots, and so on.

[0184] As a result of the above determination, the UE and the gNB have Y common relative positions of the monitoring time slots within the time slot group, for example, the first and second time slots of a time slot group having a total of four time slots become the monitoring time slots.

[0185] The UE and the gNB can then determine the actual monitoring timeslots of a particular timeslot group, which can be done on a timeslot group by timeslot group basis. As is evident from Figure 24, the UE and the gNB determine for a current timeslot group the actual monitoring timeslots in that timeslot group based on the common relative positions of the pre-determined monitoring timeslots, e.g., the first and second timeslots of that current timeslot group become the monitoring timeslots monitored by the UE.

[0186] The UE can then monitor the downlink control channel in the thus determined monitoring timeslots of the current timeslot group. Conversely, since the gNB is aware of the monitoring timeslots monitored by the UE, it can use them to transmit downlink control information to the UE.

[0187] The UE and gNB then proceed to process the next timeslot group and perform the monitoring timeslot determination steps described above again for the next timeslot group, however, instead of redetermining the common relative positions of the monitoring timeslots, the UE and gNB may simply reapply the same previously determined common relative positions of the monitoring timeslots, this time to the timeslots of the new timeslot group.

[0188] The UE operation of Figure 24 described above will now be described with reference to an exemplary scenario shown in Figure 25. Although this description is primarily concerned with how the UE performs the monitoring timeslot determination, this description is equally applicable to the base station side monitoring timeslot determination.

[0189] FIG. 25 shows the configuration of the UE's CSS and two USSs (USS#1 and USS#2) with the same distribution as the scenario assumed in FIG. 19. It is exemplarily assumed that the CSS first occurs in slot 0 and occurs in an 8-slot period, the USS#1 first occurs in slot 1 and occurs in a 4-slot period, and the USS#2 first occurs in slot 2 and occurs in a 4-slot period. At the bottom of FIG. 25, the resulting Y=2 monitoring time slots per timeslot group are shown. As is evident therefrom, the Y monitoring time slots are determined by the UE and the gNB according to the first and second criteria already detailed for the first solution. Thus, for example, the UE and the gNB determine the first and second timeslots in a timeslot group as common relative positions, since the first timeslot contains the CSS MO (see, for example, the first, third and fifth timeslot groups) and the second timeslot contains the USS#1 MO (see all timeslot groups). As shown in Figure 25, a common relative position of the monitoring timeslots, i.e., in this case, the first and second timeslots, is applied to all timeslot groups, resulting in actual monitoring timeslots 0 and 1 for the first timeslot group, actual monitoring timeslots 4 and 5 for the second timeslot group, actual monitoring timeslots 8 and 9 for the third timeslot group, etc. This ensures that the relative positions of the monitoring timeslots are the same in all timeslot groups.

[0190] The determination of the monitoring time slot according to the second solution can be implemented in various ways, two exemplary variants of which are described below. Briefly, the first variant is based on predetermining a reference time slot group among the multiple time slot groups, and the determination of the monitoring time slot (or more specifically, the common relative position of the monitoring time slot) within the reference time slot group can be performed according to the same principles as detailed in the first solution. The second variant does not rely on the reference time slot group but determines the relative position of the monitoring time slot by applying the first and second criteria to the MO of the multiple time slot groups.

[0191] More specifically, according to a first variant of the second solution, the UE and the gNB first determine a reference timeslot group from among a plurality of timeslot groups based on the current settings of the MOs of the CSS and the USS. The reference timeslot group can be determined in various ways, for example: As the first time slot group of multiple time slot groups, or As the first of several time slot groups that contain a common search space, or Among the multiple time slot groups, a time slot group that includes the most common search spaces and UE-specific search spaces in the fewest time slots is selected. It can be determined.

[0192] Other ways of determining the reference time slot group are possible.

[0193] Then, after determining the reference timeslot group, the UE and the gNB can perform a monitoring timeslot decision based on the reference timeslot group representative of multiple timeslot groups. This decision on the reference timeslot group can be performed according to any one of the implementations described in connection with the first solution above, for example as described with respect to Figures 19 to 23 (but not limited to these examples only). In order to avoid repetition, the corresponding description of the first solution is included in the first variant of the second solution and should be considered as applicable.

[0194] As a result of the first variant, the UE and the gNB have determined a common relative position of Y (or less) monitoring timeslots within the reference timeslot group.

[0195] The UE and gNB can then determine the actual monitoring time slots for all time slot groups, which can be done for each time slot group based on its Y common relative positions of the monitoring time slots pre-determined based on the reference time slot group.

[0196] Further, according to a second variant of the second solution, the UE and the gNB take into account the first and second criteria for CSS and USS monitoring opportunities for multiple timeslot groups based on the current settings of the MOs of the CSS and USS.

[0197] According to one example implementation, the UE may consider the MO of multiple timeslot groups, e.g., all timeslot groups up to the maximum period at which the CSS and USS distribution in the timeslot groups begins to repeat. For example, in the example scenario of FIG. 25, the multiple timeslot groups considered are two timeslot groups (e.g., the first and second timeslot groups) because the third timeslot group repeats the CSS / USS distribution of the first timeslot group, and the fourth timeslot group repeats the CSS / USS distribution of the second timeslot group.

[0198] In other scenarios, the maximum period is longer and therefore the number of time slot groups on which the decision is based increases. For example, in the scenario of Figure 21, the CSS MO period is 7 slots, so the maximum period is 7 time slot groups.

[0199] Then, among the multiple time slot groups, the UE and the gNB determine a time slot of the time slot group that includes the CSS MO, and determine the relative position of that time slot as the common relative position of the monitoring time slot.

[0200] Next, from among the multiple timeslot groups, the UE and gNB determine a timeslot of the timeslot group that includes the USS MO (optionally in ascending order of USS index, i.e. first USS#1, then USS#2, ...) and determine the relative position of that timeslot as the common relative position of the monitoring timeslot.

[0201] As mentioned before, the above steps of the second variant of the second solution are applied as long as there are still monitoring time slots to be determined, i.e. until the number Y is reached.

[0202] As a result of the second variant, the UE and the gNB have Y common relative positions of the monitoring timeslots, essentially as in the first variant. The UE and the gNB can then determine the actual monitoring timeslots for all timeslot groups, which can be done for each timeslot group based on the Y common relative positions of the monitoring timeslots.

[0203] One specific exemplary implementation of the second variant of the second solution can be defined based on the following algorithm: The maximum period of all configured MOs is known to the UE, and the UE can check all slot groups up to the maximum period in the following steps:

[0204] 1. Does a CSS MO occur in the first slot of any slot group? If "yes", then the Y monitoring time slots must include the first slot.

[0205] 2. Does the CSS MO occur in the second slot of any slot group? If "yes", then the Y monitor time slots must include the second slot.

[0206] 3. Repeat the above procedure for all CSS MOs and USS MOs until the slot number Y (say, 2 slots) is reached.

[0207] As will become apparent below, applying the first and second variants may result in the same or different monitoring time slots depending on the MO configuration. For illustrative purposes, the first and second variants of the second solution presented above will be described in relation to the scenario of Figure 25 already described.

[0208] As will become clear, both the first and second variants of the second solution may result in the same Y monitoring time slots shown in FIG. 25. According to the first variant, the UE and the gNB first determine a reference time slot group. In the exemplary scenario of FIG. 25, the UE and the gNB may determine, for example, a first time slot group as the reference time slot group according to one of the conditions presented above. The first time slot group is the first time slot group among the multiple time slot groups, and is also the first time slot group among the multiple time slot groups that includes a common search space, and is also the time slot group among the multiple time slot groups that includes the most (here two) common search spaces and UE-specific search spaces in the fewest time slots. By sequentially applying the first and second criteria to the reference time slot group, i.e., the first time slot group of FIG. 25, the UE and the gNB determine the first and second time slots as representing the common relative positions of the monitoring time slots.

[0209] On the other hand, according to a second variant, the UE and the gNB determine a monitoring time slot among the MOs of the first and second time slot groups (as a plurality of time slot groups). According to the first CSS-related criterion, the CSS MO is located in the first time slot of the first time slot group, so the first time slot is determined to constitute a first common relative position of the monitoring time slot. Since there are no further CSSs in the first and second time slot groups, the UE continues based on the second USS-related criterion and determines that the USS#1 is located in the second time slot of the first time slot group (also in the second time slot group). Thus, the second time slot is determined to constitute a second common relative position of the monitoring time slot.

[0210] With reference to Figures 26 and 27, it will be explained that the first and second variants of the second solution may result in different monitoring time slots. Figure 26 shows the configuration of the UE's CSS and two USSs (USS#1 and USS#2). It is exemplarily assumed that the CSS first occurs in slot 0 and occurs with a 6-slot period, the USS#1 first occurs in slot 1 and occurs with a 4-slot period, and the USS#2 first occurs in slot 2 and occurs with a 4-slot period. At the bottom of Figure 26, Y=2 monitoring time slots obtained after performing the second variant of the second solution are shown.

[0211] For example, in line with the principles of the second variant of the second solution, the UE and gNB determine that the first time slot is the common relative position of the monitoring slot because it contains the MO of the CSS. For example, within the second time slot group, the third time slot also contains the MO of the CSS, but the third time slot is not selected as the monitoring time slot because it is not consecutive. Instead, the UE and gNB determine that the second time slot (e.g., of the first time slot group) contains the MO of USS#1, and determine the second time slot as the common relative position of the monitoring time slot. The resulting Y time slots, i.e., the first and second time slots of each time slot group, are shown at the bottom of FIG. 26.

[0212] FIG. 27 shows the same configuration of the UE's CSS and two USSs (USS#1 and USS#2) as in FIG. 26. However, the result is different from the result according to the second variant described above for FIG. 26, since the resulting Y monitoring timeslots are the second and third timeslots. In line with the principle of the first variant of the second solution, the UE and gNB determine the second timeslot group as the reference timeslot group, since it is the timeslot group that contains the most CSSs and USSs (here three) in the fewest timeslots (here two), while the first timeslot group also has three CSSs and USSs, but distributed over three timeslots. Applying the first and second criteria to the reference timeslot group results in the second and third timeslots of the reference timeslot group being determined by the UE and gNB as the common relative positions of the monitoring timeslots. Correspondingly, the same common relative positions are applied to all timeslot groups.

[0213] FIG. 28 shows the same configuration of the UE's CSS and two USSs (USS#1 and USS#2) as in FIG. 26 and FIG. 27. However, here it is assumed that the determination of the monitoring time slots allows for discontinuous monitoring slots, which may significantly affect the determination of the common relative positions of the monitoring time slots. In this example of FIG. 28, it is assumed that the UE and the gNB perform the second variant of the second solution. Correspondingly, the UE first determines that the first time slot (e.g., of the first time slot group) contains a CSS MO and determines that this is the common relative position of the monitoring time slots. Furthermore, since the third time slot (e.g., of the second time slot group) also contains a CSS MO, it is determined that the third time slot is the common relative position of the monitoring time slots. Since there is no constraint that the positions of the monitoring time slots obtained in this way must be consecutive, the Y monitoring time slots become the first and third time slots of each time slot group.

[0214] In the above implementation of the second solution, it was simply assumed that the decision is determined only once and then used for all the multiple time slot groups. However, in a further implementation of the second solution, the previously determined common relative position of the monitoring time slots is applied to the time slot group until the monitoring opportunity setting is changed. The common relative position of the monitoring time slots has been determined based on the current setting of the MO (see above). It is therefore advantageous to adapt the common relative position of the monitoring time slots to the new MO setting to arrive at the most appropriate monitoring position for the current MO setting.

[0215] Specifically, the UE and the gNB determine whether the currently used setting of the MO of the UE is or has been changed. If the MO setting has not been changed, the UE and the gNB continue to use the previously determined common relative position of the monitoring timeslot.

[0216] On the other hand, if the MO configuration is or has been changed, the UE and the gNB may need to re-determine the common relative position of the monitoring timeslots, for example according to any of the implementations of the second solution already described in detail above.

[0217] This operation is illustrated in Figure 29 on the UE side, which is very similar to the operation in Figure 24. Figure 29 further specifies that the two steps of determining the common relative position of the monitoring timeslot(s) are performed based on the current setting of the MO, with respect to the current setting of the MO. The UE operation also includes the above check as to whether the MO setting has changed. If "yes" (i.e., the MO setting has changed), the UE operation goes back to redetermining the common relative position of the monitoring timeslot(s) at the new MO setting at that time (which is then considered as the "current setting of the MO" after the MO setting change).

[0218] Such an implementation may have the advantage that the complexity for determining the monitoring timeslots is reduced, since the positions of the Y monitoring timeslots do not need to be determined for each timeslot group, and do not necessarily change for each timeslot group. Furthermore, this implementation maintains flexibility for adapting the monitoring timeslots to new situations, since the monitoring timeslots are re-determined when the MO configuration is changed.

[0219] Figure 30 shows two different configurations of the UE's CSS and two USSs (USS#1 and USS#2), and at the bottom shows how a change in MO configuration results in different monitoring time slots before and after the MO configuration change.

[0220] Assume that the common relative positions of the monitoring time slots are the first and second time slots of each time slot group due to the MO settings before the change. This determination may be the same as that already described in detail with respect to FIG.

[0221] Assume further that with the modified MO configuration, the common relative positions of the monitoring timeslots are different, specifically the second and third timeslots of each timeslot group. Since there is a CSS in slot 17 of the fifth slot group (i.e., the second timeslot of that fifth timeslot group), the decision is to use the second timeslot of the timeslot group for monitoring. Furthermore, the third timeslot is selected for monitoring because it contains USS#2 and meets the constraint that the monitoring timeslots must be consecutive.

[0222] The following describes various implementations of the above step of determining whether the MO configuration has changed.

[0223] According to the first implementation, the MO configuration is considered to be changed when configuration information for configuring the MO is received at the UE from the serving base station or transmitted by the serving base station. For example, the new MO configuration can be indicated by an RRC message, for example in the context of a configured search space and a control resource set. Such a reconfiguration of the MO can occur, for example, when the UE changes a monitoring beam for DL ​​reception, and the serving base station can inform the UE of a new MO configuration suitable for the DL serving beam from the gNB.

[0224] According to the second implementation, the MO configuration is considered to be changed when the UE switches from a current serving beam to a new serving beam to receive a downlink control channel from the serving base station. Furthermore, the UE determines the MO configuration based on the beam used to receive the downlink control channel and the stored configuration information. The stored configuration information includes information that associates different beams with different MO configurations. Correspondingly, no direct reconfiguration of the MO by a message from the serving base station is required, and the UE can autonomously determine a new beam-specific MO based on the pre-stored configuration information (e.g., pre-configured by the serving base station).

[0225] Whether the UE switches beams can be indicated by, for example, the serving base station. Thus, when the UE receives such a beam change indication, the UE determines a new MO configuration and then re-determines a new monitoring time slot in the new MO configuration as described above. In a 5G compliant solution, the TCI (Transmission Configuration Indicator) can be used as the serving beam change indication.

[0226] Alternatively, during initial access, the UE selects the best SSB as the serving beam and reports this to the gNB by sending Msg1 using the corresponding RACH resource. After receiving Msg1, the gNB knows which beam is the serving beam preferred by the UE and uses such beam as the UE serving beam throughout the initial access procedure. After the RRC connection is established, the UE can send a beam measurement report to the gNB to indicate other serving beam candidates. The gNB can then decide whether to switch the serving beam of the UE and, if so, send a beam switch indication, such as a TCI, to the UE.

[0227] In the above implementation, we simply assumed that a change in the MO configuration causes a redetermining of the monitoring timeslot. However, it is possible that the change in the MO configuration is such that a redetermining of the monitoring timeslot is not actually necessary. According to other implementations, only a change in the MO configuration that leads to the MO being included in a different timeslot than the previous MO configuration will cause a redetermining of the monitoring timeslot.

[0228] Specifically, changes to the monitoring opportunity settings may refer to various setting items such as: -The number of monitoring opportunities is changed - The monitoring period is changed The timing of the OFDM symbols for monitoring opportunities is changed - Timing of monitoring opportunity time slots is changed -The aggregation level of monitoring opportunities is changed -The number of monitor candidates per aggregation level is changed As is evident from this list of possible changes in MO configuration, some of these changes, e.g., regarding the number of MOs, the timing of OFDM symbols, the aggregation level, and the number of monitoring candidates per aggregation level, do not necessarily result in a change in the time slot.

[0229] Therefore, another implementation of the second solution includes the additional step of determining whether the change in the configuration of the monitoring opportunity causes the time slots of any of the monitoring opportunities to be different compared to the previous configuration of the monitoring opportunity. Correspondingly, if the time slots of any of the monitoring opportunities are different, the MO configuration is considered to have indeed changed and the UE and gNB proceed to redetermine the monitoring slots based on the changed MO configuration. Conversely, if the change in the MO configuration does not cause the time slots of any of the monitoring opportunities to be different, the change in the MO configuration is considered to have no effect, and the UE and gNB continue to use the old monitoring time slots.

[0230] In a further implementation, the second solution of the improved downlink control channel monitoring procedure may also use a different first criterion, i.e., that the monitoring time slot includes a monitoring opportunity associated with a common search space of the reduced set of CSSs. This has already been described in detail above with respect to the improved downlink control channel monitoring procedure in connection with Figures 14 to 17 and is equally applicable to the second solution. In summary, the reduced set of CSSs may include CSSs that are not configured for all UEs, e.g., Type-1 CSSs and Type-3 CSSs that are configured by a dedicated message to the UE. The remaining CSSs that are not included in the reduced set of CSSs (CSSs that are commonly configured for all UEs, e.g., Type-1 CSSs, Type-0 CSSs, Type-0A CSSs, and Type-2 CSSs that are not configured by a dedicated message) may be exemplarily monitored by the UE in further monitoring opportunities in the time slot group other than the Y monitoring time slots. Conversely, the BS may transmit the remaining CSSs in further monitoring opportunities in the time slot group other than the Y monitoring time slots, defined by the corresponding monitoring opportunities of the remaining CSSs.

[0231] The above second solution and its variants and implementations have been described mainly from the UE's perspective, however, the above monitoring slot determination can be performed in exactly the same way in the UE and the BS, so the above second solution and its variants and implementations are also applicable to the base station side.

[0232] The BS and UE differ in how the resulting monitoring timeslots are used in further processing: the UE uses the monitoring timeslots for monitoring functions (see Figure 14) and the BS uses the monitoring timeslots for transmitting downlink control information (see Figure 16).

[0233] <Variations of the above solution> Below, various variations of the basic solution described above (see, for example, Figures 13 to 17), as well as the first solution (see, for example, Figures 18 to 23) and the second solution (see, for example, Figures 24 to 30) are shown.

[0234] In various implementations of the improved downlink control channel monitoring procedures described above and below, e.g., in connection with the first and second solutions, it has been exemplarily assumed that the number of time slots X in each time slot group is 4. However, the basic invention and the first and second solutions are not limited in this respect, and the number of time slots X in each time slot group may be other numbers, e.g., 2, 3, 5, 6, 7, 8, 9, etc.

[0235] In an exemplary implementation, the number X of time slots within each time slot group can be determined based on, for example, the subcarrier spacing used for the downlink control channel and the corresponding information stored in the UE and the gNB. The stored information can be set by the base station or pre-set in the sense that it is fixed by the 3GPP standard. In one example, the stored information includes an association between different subcarrier spacings and one or more of different numbers of time slots. For example, it can be assumed that the number X of time slots within a time slot group is 4 for a subcarrier spacing of 480 kHz and 8 for a subcarrier spacing of 960 kHz.

[0236] For example, in relation to the first and second solutions, in various implementations of the improved downlink control channel monitoring procedures described above and below, it is exemplarily assumed that the number Y of monitoring time slots within a time slot group is 1 slot or 2 slots. However, the basic invention as well as the first and second solutions are not limited in this regard, and the number Y of monitoring time slots within each time slot group can take other values in order to enable the UE to save power, provided that it must be less than the number X of time slots within each time slot group, i.e., 1 ≤ Y < X. For example, the number Y of monitoring time slots within a time slot group can be 1 or 2 when X = 3, can be 1, 2, or 3 when X = 4, can be 1, 2, 3, or 4 when X = 5, and so on. In other exemplary embodiments, the minimum number of monitoring time slots within a time slot group is 1 slot, and the maximum number of monitoring time slots within a time slot group is half of the number X of time slots within each time slot group, i.e., 1 ≤ Y < X / 2.

[0237] In an exemplary implementation, the number Y of monitoring time slots in a timeslot group can be determined from capability information stored in the UE, since it depends on the UE's capability of the number of timeslots it can monitor (and process) in a particular timespan. Correspondingly, in such a variant, the UE may transmit capability information of the number Y of monitoring time slots in a timeslot group to a serving base station serving the UE, so that the serving base station has the same information as the UE and can determine the monitoring time slots accordingly in the same way.

[0238] In various implementations of the improved downlink control channel monitoring procedure described above and below, e.g. in connection with the first and second solutions, it was simply assumed that the UE has already been configured with different monitoring occasions for each search space as part of the monitoring function. In one exemplary implementation, the configuration of the monitoring function can be implemented using configuration information transmitted from the base station to the UE. The configuration information provides the UE with the necessary information to determine at least one or more monitoring occasions for which the UE will monitor the downlink control channel. According to one example in accordance with the 5G NR standard, this configuration can be based on the above-mentioned information elements ControlResourceSet and SearchSpace, e.g. as defined above in 3GPP TS38.331v16.5.0 section 6.3.2.

[0239] Various implementations of the improved downlink control channel monitoring procedure described above and below, for example in connection with the first and second solutions, have been described as generally being performed in the UE and the gNB. Meanwhile, in exemplary implementations, the improved downlink control channel monitoring procedure is primarily performed in certain scenarios, such as scenarios where the subcarrier spacing of the downlink control channel is greater than 120 kHz, e.g., 480 kHz or 960 kHz. Additionally or alternatively, the improved downlink control channel monitoring procedure is primarily performed in a new frequency range above 52.6 GHz, e.g., a frequency range of 52.6 GHz to 71 GHz.

[0240] In various implementations of the improved downlink control channel monitoring procedures described above and below, for example in relation to the first and second solutions, a situation may arise in which a back-to-back problem occurs. A back-to-back problem is a situation in which consecutive monitoring time slots straddle a time slot group boundary. In the first and second solutions, the back-to-back problem may occur.

[0241] An exemplary scenario in which the back-to-back problem occurs is shown in FIG. 31, where the configuration of the UE's CSS and two USSs (USS#1 and USS#2) is assumed for the sake of illustration. It is assumed for the sake of illustration that the CSS first occurs in slot 0 and occurs in a 6-slot period, the USS#1 first occurs in slot 3 and occurs in a 4-slot period, and the USS#2 first occurs in slot 2 and occurs in a 4-slot period. In the diagram of FIG. 31, it is assumed that the monitoring time slots are determined according to the implementation of the first solution described above. The result of determining the Y monitoring slots for each time slot group is shown at the bottom of FIG. 31, i.e., monitoring time slots 0 and 1 in the first time slot group, monitoring time slots 6 and 7 in the second time slot group, monitoring time slots 10 and 11 in the third time slot group, and monitoring time slots 12 and 13 in the fourth time slot group. Correspondingly, a back-to-back problem occurs where monitoring timeslots 10-13 straddle the boundary of the third and fourth timeslot groups. Such an extended sequence of consecutive monitoring timeslots is disadvantageous in that it requires higher downlink control channel processing capability of the UE, possibly much higher than the capabilities of the UE.

[0242] The back-to-back problem can be solved in a variety of ways:

[0243] According to a first implementation, an additional criterion for determining the monitoring time slot is defined, namely that there is a minimum time gap of one time slot between the monitoring time slots of two consecutive time slot groups, in other words, the monitoring time slot is determined such that there is a minimum time gap of one time slot between the last monitoring time slot of the nth time slot group and the first monitoring time slot of the n+1th time slot group.

[0244] According to the second implementation, the determination of the monitoring time slots may remain the same, not expanded to take into account the third criterion above. Thus, the same monitoring time slots are determined initially, including the back-to-back situation of the monitoring time slots, for example as shown in Figure 31. However, the UE is exceptionally allowed to skip monitoring the MO in one of two consecutive monitoring time slots involved in the back-to-back situation.

[0245] The third implementation is similar to the second implementation, but with the exception that instead of skipping the execution of the monitoring function for the entire monitoring timeslot, the UE is allowed to skip the execution of the monitoring function for a subset of monitoring opportunities in one of two consecutive monitoring timeslots involved in a back-to-back situation.

[0246] Figure 32 shows the same UE CSS / USS configuration as in Figure 31, but with two different outcomes of the determination of the monitoring timeslots to solve the back-to-back problem. At the bottom of Figure 32, the result of the second implementation above is shown, according to which the monitoring timeslots are determined as before (see Figure 31), with the exception that the UE is allowed to skip monitoring timeslot 12 (the second timeslot involved in the back-to-back situation).

[0247] The penultimate row of FIG. 32 shows the result of the first implementation above, where the illustrated monitoring timeslots are the result of additionally considering the third criterion that there must be a minimum time gap of one timeslot between the monitoring timeslots of two consecutive timeslot groups. Correspondingly, when determining the monitoring timeslots of the fourth timeslot group, the UE and gNB may not select timeslot 12 as the monitoring timeslot, since it violates the third criterion and creates a back-to-back problem. Instead, timeslots 14 and 15 are determined as the monitoring timeslots, since they contain the MOs of USS#1 and USS#2. As can be seen, the resulting monitoring timeslots do not create a back-to-back problem.

[0248] The back-to-back problem may also occur in the second solution, especially at the boundaries when the MO configuration is changed and when the monitoring time slot is changed as a result of the MO configuration change. Such a situation is illustrated in FIG. 33. As is evident from FIG. 33, assume for the sake of illustration that the MO configuration is changed between the third and fourth time slot groups. Specifically, the change in MO configuration involves a different position of the CSS MO, this time occurring for the first time in slot 17 (with the same 8 slot period), a different position of the USS#1 MO, this time occurring for the first time in slot 12 (with the same 4 slot period), and a different position of the USS#2 MO, this time occurring for the first time in slot 14 (with the same 4 slot period).

[0249] Due to the particular distribution of CSS / USS in the two different MO configurations, the back-to-back problem occurs in monitoring timeslots 10, 11, 12, and 13, which are consecutive and require the UE to monitor and process the downlink channel for four consecutive timeslots. This is shown in the top row showing Y monitoring slots (labeled “Back-to-Back Problem”).

[0250] The above first, second and third implementations for solving the back-to-back problem described in FIG. 32 can also be applied to the scenario in FIG.

[0251] More specifically, in line with the first implementation, the UE may determine different monitoring time slots for subsequent MO configurations by further considering that there is a minimum time gap of one time slot between the monitoring time slots of two consecutive time slot groups. The resulting monitoring time slots are shown in the second row of Y monitoring time slots in Figure 33 (labeled "with time gap criterion"). The monitoring time slots are shifted by one time slot to become the second and third time slots of each time slot group, respectively.

[0252] Furthermore, in line with the second implementation, the UE may be exceptionally permitted to skip MO monitoring in one of two consecutive monitoring timeslots involved in a back-to-back situation, such that in the scenario of Figure 33, the UE may skip PDCCH monitoring in slot 12. This is evident from the third row of Figure 33 (labeled "Skip Monitoring"), which shows Y monitoring timeslots.

[0253] In the illustrated second implementation of Fig. 33, the resulting monitoring slot (relative position of the third and fourth time slots in the time slot group) is further applied to all subsequent time slot groups. However, this may not be optimal for the subsequent time slot groups, e.g., in Fig. 33, the prioritized USS#1 MO is not monitored by the UE. Therefore, according to a further variant of this second implementation, the third criterion is applied only to the first time slot group of the new MO configuration, and the usual determination of the monitoring time slot according to the second solution is applied to the remaining time slot groups after the first time slot group of the new MO configuration.

[0254] Although not shown in Figure 33, a third implementation can also be applied by the UE to avoid the back-to-back problem, specifically, the UE is allowed to exceptionally skip performing the monitoring function for a subset of monitoring opportunities in one of two consecutive monitoring time slots involved in a back-to-back situation. For example, since the MO of USS#1 is causing the back-to-back problem, the UE may be allowed to skip monitoring the USS#1 MO in time slot 12, while the USS#1 MO of the subsequent time slot group is monitored by the UE along with the monitoring time slots occurring in the first and second time slots of each time slot group.

[0255] According to a further fourth implementation, the UE uses the old monitoring time slot for the first time slot group of the new MO configuration (e.g., for the fourth slot group in FIG. 33) and uses the new monitoring time slot only at the time of the second time slot group of the new MO configuration. In other words, the use of the new monitoring time slot determined based on the new MO configuration is deferred by one time slot group. This is shown in the last row of FIG. 33 (labeled "Deferred"), which shows Y monitoring slots using dotted arrows in the fourth slot group. Thereby, in the fourth slot group, the UE monitors the MOs in the monitoring time slots, e.g., here timeslots 14 and 15, and in particular the USS#2 MO. Meanwhile, the USS#1 MO is not monitored by the UE, since it is located outside the Y monitoring time slots.

[0256] Further aspects According to a first aspect, there is provided a user equipment including: a processing circuit in the UE determines, for two or more timeslot groups, one or more timeslots in the timeslot group to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message; the processing circuit determines the monitoring timeslot in the timeslot group according to: A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; 4. Perform the procedure according to one or more of the following:

[0257] The processing circuitry then monitors the downlink control channel in the determined one or more monitor time slots of the time slot group.

[0258] According to a second aspect provided in addition to the first aspect, a first criterion relating to a common search space is considered before a second criterion relating to a UE-specific search space for determining a monitoring time slot within the time slot group.

[0259] According to a third aspect provided in addition to the first or second aspect, for determining the monitoring time slot, the processing circuit considers the UE-specific search spaces in order of priority, with the lower the index of the UE-specific search space, the higher the priority it has to be included in the monitoring time slot.

[0260] According to a fourth aspect provided in addition to any one of the first to third aspects, the first criterion further comprises: - the monitoring time slot includes monitoring opportunities associated with common search spaces of a first set of common search spaces of the downlink control channel, the first set of common search spaces not including all common search spaces configured for the UE; It is defined as:

[0261] In an optional implementation thereof, the first set of common search spaces includes a common search space configured by a dedicated message to the UE and includes a common search space configured commonly for a group of UEs. In a further optional implementation thereof, the first set of common search spaces includes a Type-1 common search space and a Type-3 common search space configured by a dedicated message to the UE by the 5G communication system.

[0262] According to a fifth aspect provided in addition to the fourth aspect, the processing circuit, in operation, monitors a common search space that does not belong to the set of first common search spaces in an additional monitoring time slot of a time slot group different from the monitoring time slot of the time slot group.

[0263] According to a sixth aspect provided in addition to any one of the first to fifth aspects, the UE is permitted not to monitor the downlink control channel in time slots of the time slot group which are not monitoring time slots.

[0264] According to a seventh aspect provided in addition to any one of the first to sixth aspects, the determination of the monitoring time slot is performed individually for each time slot group.

[0265] According to an eighth aspect provided in addition to any one of the first to sixth aspects, the determination of the monitoring time slot is performed jointly for a plurality of time slot groups. The determination results in a common relative position of the monitoring time slot in each time slot group of the plurality of time slot groups. The processing circuitry, in operation, applies the determined common relative position of the monitoring time slot to determine a monitoring time slot for each of the plurality of time slot groups. In an optional implementation, the determination of the monitoring time slot based on the common relative position of the monitoring time slot is performed until a monitoring opportunity setting is changed.

[0266] According to a ninth aspect provided in addition to the eighth aspect, the processing circuit, in operation, determines whether a configuration of the monitoring opportunity has been changed. If it is determined that the configuration of the monitoring opportunity has been changed, the processing circuit, in operation, performs again the determination of the monitoring time slot for the other plurality of time slot groups after the change of the configuration of the monitoring opportunity according to the changed configuration of the monitoring opportunity. The determination results in another common relative position of the monitoring time slot within each time slot group of the other plurality of slot groups. Furthermore, the processing circuit, in operation, applies the determined another common relative position to determine the monitoring time slot for the other plurality of time slot groups after the change of the configuration of the monitoring opportunity.

[0267] According to a tenth aspect, provided in addition to the eighth or ninth aspect, the determination of the monitoring time slot is performed based on a reference time slot group of the plurality of time slot groups. In operation, the processing circuitry includes: Whether it is the first time slot group of multiple time slot groups, It is the first of multiple time slot groups that contain a common search space, or Among the multiple time slot groups, a group including the most common search space and the most UE-specific search space in the fewest time slots; The time slots are determined as a group.

[0268] According to an eleventh aspect provided in addition to the eighth or ninth aspect, the determination of the monitoring time slot is performed taking into account monitoring opportunities of the multiple time slot groups. In an optional implementation thereof, for the determination of the monitoring time slot of the multiple time slot groups, the processing circuit takes into account a first criterion and a second criterion for monitoring opportunities of the multiple time slot groups.

[0269] According to a twelfth aspect provided in addition to any one of the eighth to eleventh aspects, the processing circuit, in operation, determines that a configuration of a monitoring occasion has been changed when a receiver of the UE, in operation, receives configuration information for setting a monitoring occasion from a serving base station. In an optional implementation thereof, the configuration information of the monitoring occasion is received in a message of a radio resource control (RRC) protocol.

[0270] According to a thirteenth aspect provided in addition to any one of the eighth to twelfth aspects, the processing circuit, in operation, determines that a configuration of a monitoring opportunity has changed when the UE switches from a current beam to a new beam for receiving a downlink control channel from a serving base station. In an optional implementation thereof, the processing circuit, in operation, determines the monitoring opportunity based on a beam used for receiving the downlink control channel from the serving base station and stored configuration information. The stored configuration information includes different configuration information associated with different beams for setting beam-specific monitoring opportunities. In an optional implementation thereof, the processing circuit, in operation, determines that the UE switches from a current beam to a new beam based on an indication received from the serving base station.

[0271] According to a fourteenth aspect provided in addition to any one of the eighth to thirteenth aspects, the change in the setting of the monitoring opportunity is - the number of monitoring opportunities is changed; - The monitoring period is changed; The timing of the OFDM symbols of the monitoring opportunities is changed; - the timing of the time slots of monitoring opportunities is changed; - the aggregation level of monitoring opportunities is changed; The number of monitoring candidates per aggregation level may change. Includes one or more of:

[0272] In an optional implementation, the processing circuitry, in operation, further determines whether the change in the configuration of the monitoring opportunity causes a time slot of any monitoring opportunity to be different compared to a previous configuration of the monitoring opportunity. If the time slot of any monitoring opportunity becomes different, the processing circuitry determines that the configuration of the monitoring opportunity has been changed for purposes of whether the monitoring slot determination should be re-performed. If the time slot of any monitoring opportunity does not become different, the processing circuitry determines that the configuration of the monitoring opportunity has not been changed for purposes of whether the monitoring slot determination should be re-performed.

[0273] According to a fifteenth aspect provided in addition to any one of the first to fourteenth aspects, the time slots are grouped into a plurality of time slot groups, the time slot groups being contiguous in time and non-overlapping, each time slot group including X time slots. In an optional implementation thereof, the processing circuitry is operative to determine from information stored in the UE a number of time slots X in each time slot group based on a subcarrier spacing used for the downlink control channel. In a further optional implementation thereof, the stored information includes an association between different subcarrier spacings and one or more of different numbers of time slots, optionally the number of time slots X in the time slot group is 4 for a subcarrier spacing of 480 kHz and 8 for a subcarrier spacing of 960 kHz.

[0274] According to a sixteenth aspect provided in addition to any one of the first to fifteenth aspects, the determination of the monitoring time slot is performed such that the determined monitoring time slots in the time slot group are consecutive, or The determination of the guard time slots is performed regardless of whether the determined guard time slots within a time slot group are contiguous or not.

[0275] According to a 17th aspect provided in addition to any one of the 1 to 16 aspects, the processing circuit, in operation, determines a number Y of monitoring time slots in the timeslot group from information stored in the UE, optionally the stored information being related to a capability of the UE, and optionally a minimum number of monitoring time slots in the timeslot group is one slot and a maximum number of monitoring time slots in the timeslot group is half the number X of time slots in each timeslot group. In an optional implementation thereof, the UE, in operation, comprises a transmitter, which transmits information of the number Y of monitoring time slots in the timeslot group to a serving base station serving the UE.

[0276] According to an 18th aspect provided in addition to any one of the 1 to 17 aspects, the UE, in operation, comprises a receiver for receiving configuration information for configuring a monitoring function in the UE from a serving base station serving the UE, the configuration information configuring one or more monitoring occasions for the UE to monitor a downlink control channel. In an optional implementation, in operation, the processing circuit determines, based on the received configuration information, one or more monitoring occasions for the UE to monitor the downlink control channel.

[0277] According to a 19th aspect provided in addition to any one of the first to 18th aspects, the determination of the monitoring time slot in the time slot group is A subcarrier spacing used for the downlink control channel of greater than 120 kHz, optionally with a subcarrier spacing of 480 kHz or 960 kHz or greater; and a frequency range over which the downlink control channel is transmitted, above 52.6 GHz, optionally in the frequency range of 52.6 GHz to 71 GHz; is performed on one or more of

[0278] According to a twentieth aspect, provided in addition to any one of the first to nineteenth aspects, the determination of the monitoring time slot within the time slot group is performed by the processing circuit according to a third criterion that there is a minimum time gap of one time slot between the monitoring time slots of two consecutive time slot groups.

[0279] According to a 21st aspect provided in addition to any one of the 1st to 19th aspects, when two monitoring time slots respectively belonging to two consecutive time slot groups are consecutive to each other, the processing circuit, in operation, Skipping the execution of one monitoring function out of two consecutive monitoring time slots, or Skipping execution of a monitoring function for a subset of monitoring opportunities in one of two consecutive monitoring time slots. Determine.

[0280] According to a twenty-second aspect, a method for transmitting a signal to a UE, the method comprising: determining, for two or more timeslot groups, one or more timeslots in the timeslot groups to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: monitoring a downlink control channel in the determined one or more monitoring time slots of the time slot group; A method is provided, comprising:

[0281] According to a twenty-third aspect, there is provided a base station comprising: a processing circuit which, in operation, for two or more timeslot groups, determines one or more timeslots in the timeslot groups to be monitored by a user equipment UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message transmitted from the base station. The processing circuit determines the monitoring timeslots in the timeslot group by: A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; 4. Perform the procedure according to one or more of the following:

[0282] A transmitter of the base station transmits a downlink control information message to the UE on a downlink control channel in at least one of the determined one or more monitor time slots of the time slot group.

[0283] According to a 24th aspect provided in addition to the 23rd aspect, a first criterion regarding a common search space is considered before a second criterion regarding a UE-specific search space for determining a monitoring time slot within the time slot group.

[0284] According to a 25th aspect, provided in addition to the 23rd or 24th aspects, for determining the monitoring time slot, the processing circuit considers the UE-specific search spaces in order of priority, with the lower the index of the UE-specific search space having a higher priority for inclusion in the monitoring time slot.

[0285] According to a 26th aspect provided in addition to any one of the 23rd to 25th aspects, the first criterion further comprises: - the monitoring time slot includes monitoring opportunities associated with common search spaces of a first set of common search spaces of the downlink control channel, the first set of common search spaces not including all common search spaces configured for the UE; It is defined as:

[0286] In an optional implementation thereof, the first set of common search spaces includes a common search space configured by a dedicated message to the UE and includes a common search space configured commonly for a group of UEs. In a further optional implementation thereof, the first set of common search spaces includes a Type-1 common search space and a Type-3 common search space configured by a dedicated message to the UE by the 5G communication system.

[0287] According to a 27th aspect provided in addition to the 26th aspect, the processing circuit, in operation, transmits a downlink control information message for a common search space not belonging to the first set of common search spaces in an additional monitoring time slot of a time slot group different from the monitoring time slot of the time slot group.

[0288] According to a 28th aspect provided in addition to any one of the 23rd to 27th aspects, the determination of the monitoring time slot is performed individually for each time slot group.

[0289] According to a 29th aspect provided in addition to any one of the 23rd to 27th aspects, the determination of the monitoring time slot is performed for a plurality of time slot groups jointly, the determination resulting in a common relative position of the monitoring time slot within each time slot group of the plurality of time slot groups. The processing circuitry, in operation, applies the determined common relative position of the monitoring time slot to determine a monitoring time slot for each of the plurality of time slot groups. In an optional implementation thereof, the determination of the monitoring time slot based on the common relative position of the monitoring time slot is performed until a monitoring opportunity setting is changed.

[0290] According to a 30th aspect provided in addition to the 29th aspect, the processing circuit, in operation, determines whether a configuration of the monitoring opportunity has been changed. If it is determined that the configuration of the monitoring opportunity has been changed, the processing circuit, in operation, performs again a determination of the monitoring time slot for the other plurality of time slot groups after the change of the configuration of the monitoring opportunity according to the changed configuration of the monitoring opportunity, the determination resulting in another common relative position of the monitoring time slot within each time slot group of the other plurality of slot groups. In operation, the processing circuit applies the determined another common relative position to determine the monitoring time slot for the other plurality of time slot groups after the change of the configuration of the monitoring opportunity.

[0291] According to a thirty-first aspect provided in addition to the twenty-ninth or thirtieth aspect, the determination of the monitoring time slot is performed based on a reference time slot group of the plurality of time slot groups. In operation, the processing circuitry includes: Whether it is the first time slot group of multiple time slot groups, It is the first of multiple time slot groups that contain a common search space, Among multiple time slot groups, which includes the most common search spaces and UE-specific search spaces; The time slots are determined as a group.

[0292] According to a thirty-second aspect provided in addition to the twenty-ninth or thirtieth aspects, the determination of the monitoring time slot is performed taking into account monitoring opportunities of the multiple time slot groups. In an optional implementation thereof, for the determination of the monitoring time slot of the multiple time slot groups, the processing circuit takes into account a first criterion and a second criterion for monitoring opportunities of the multiple time slot groups.

[0293] According to a 33rd aspect provided in addition to any one of the 29th to 32nd aspects, the processing circuit, during operation, determines that the setting of the monitoring occasion has been changed when a transmitter of the base station, during operation, transmits setting information to the UE for setting a monitoring occasion for the UE.

[0294] According to a 34th aspect provided in addition to any one of the 29th to 33rd aspects, the processing circuit, in operation, determines that a configuration of a monitoring opportunity has changed when the UE switches from a current beam to a new beam to receive a downlink control channel from a base station. In an optional implementation thereof, the processing circuit, in operation, determines the monitoring opportunity based on a beam used by the UE to receive the downlink control channel from the base station and stored configuration information, the stored configuration information including different configuration information associated with different beams for setting beam-specific monitoring opportunities. In a further optional implementation thereof, the transmitter, in operation, transmits an instruction to the UE instructing the UE to switch from the current beam to the new beam.

[0295] According to a 35th aspect provided in addition to any one of the 29th to 34th aspects, the change in the setting of the monitoring opportunity is - the number of monitoring opportunities is changed; - The monitoring period is changed; The timing of the OFDM symbols of the monitoring opportunities is changed; - the timing of the time slots of monitoring opportunities is changed; - the aggregation level of monitoring opportunities is changed; The number of monitoring candidates per aggregation level may change. Includes one or more of:

[0296] In that optional implementation, the processing circuitry, in operation, further determines whether the change in the configuration of the monitoring opportunity causes a time slot of any monitoring opportunity to be different compared to a previous configuration of the monitoring opportunity. If the time slot of any monitoring opportunity becomes different, the processing circuitry determines that the configuration of the monitoring opportunity has been changed for purposes of whether the monitoring slot determination should be re-performed. If the time slot of any monitoring opportunity does not become different, the processing circuitry determines that the configuration of the monitoring opportunity has not been changed for purposes of whether the monitoring slot determination should be re-performed.

[0297] According to a thirty-sixth aspect, a method for transmitting a signal to a base station, the method comprising: determining, for two or more timeslot groups, one or more timeslots in the timeslot group to be monitored by the user equipment UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message transmitted from a base station; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: transmitting a downlink control information message to the UE on a downlink control channel in at least one of the determined one or more monitoring time slots of the time slot group; A method is provided, comprising:

[0298] According to a thirty-seventh aspect, there is provided an integrated circuit that, in operation, controls a process of a user equipment, the process being executed by the user equipment, determining, for two or more timeslot groups, one or more timeslots in the timeslot groups to be monitored by the UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: monitoring a downlink control channel in the determined one or more monitoring time slots of the time slot group; An integrated circuit is provided, comprising:

[0299] According to a thirty-eighth aspect, there is provided an integrated circuit that, in operation, controls a process of a base station, the process being executed by the base station, determining, for two or more timeslot groups, one or more timeslots in the timeslot group to be monitored by the user equipment UE according to a monitoring function, the monitoring function being operated by the UE to monitor a downlink control channel at one or more monitoring occasions in the one or more timeslots for the purpose of receiving a downlink control information message transmitted from a base station; The determination of the monitoring time slot within the time slot group is A first criterion that the monitoring time slot includes a monitoring opportunity associated with a common search space of a downlink control channel; A second criterion that the monitoring time slot includes a monitoring opportunity associated with a UE-specific search space of the downlink control channel; and performing one or more of the following: transmitting a downlink control information message to the UE on a downlink control channel in at least one of the determined one or more monitoring time slots of the time slot group; An integrated circuit is provided, comprising:

[0300] Further variations including hardware and software implementations of the present disclosure 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 such as an integrated circuit, 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 (integrated circuit), a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. However, the technology for realizing the integrated circuit is not limited to the LSI, and may be realized using a dedicated circuit, a general-purpose processor, or a processor for a specific application. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of an LSI or a reconfigurable processor that can reconfigure the connection and settings of the 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.

[0301] The present disclosure may be implemented by any type of apparatus, device or system having communication capabilities, referred to as a communications apparatus.

[0302] 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.

[0303] 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.

[0304] 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.

[0305] Communications may include, for example, exchanging data via cellular systems, wireless LAN systems, satellite systems, and the like, as well as various combinations thereof.

[0306] 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.

[0307] Additionally, the communications equipment may include infrastructure facilities such as, for example, 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.

[0308] (Control signal) In this disclosure, the downlink control signal (information) related to this disclosure may be a signal (information) transmitted via a PDCCH of a physical layer, or may be a signal (information) transmitted via a MAC control element (CE) or RRC of a higher layer. The downlink control signal may be a predefined signal (information).

[0309] The uplink control signal (information) related to the present disclosure may be a signal (information) transmitted via a PUCCH of a physical layer, or may be a signal (information) transmitted via a MAC CE or RRC of a higher layer. Also, the uplink control signal may be a predefined signal (information). The uplink control signal may be replaced by uplink control information (UCI), first stage sidelink control information (SCI), or second stage SCI.

[0310] (base station) In the present disclosure, the base station may be, for example, a Transmission Reception Point (TRP), a cluster head, an access point, a Remote Radio Head (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a base unit, or a gateway. Also, in sidelink communication, a terminal may be employed instead of the base station. The base station may be a relay device that relays communication between an upper node and a terminal. The base station may be a roadside unit.

[0311] (uplink / downlink / sidelink) The present disclosure may be applied to any of the uplink, downlink, and sidelink.

[0312] The present disclosure may apply, for example, to uplink channels such as PUSCH, PUCCH, and PRACH, downlink channels such as PDSCH, PDCCH, and PBCH, and sidelink channels such as the Physical Sidelink Shared Channel (PSSCH), the Physical Sidelink Control Channel (PSCCH), and the Physical Sidelink Broadcast Channel (PSBCH).

[0313] The PDCCH, PDSCH, PUSCH, and PUCCH are examples of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel, respectively. The PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel, respectively. The PBCH and PSBCH are examples of a broadcast channel, and the PRACH is an example of a random access channel.

[0314] (Data Channel / Control Channel) The present disclosure may be applied to both data channels and control channels. The channels in the present disclosure may be replaced with data channels including PDSCH, PUSCH, and PSSCH, and / or control channels including PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0315] (reference signal) In this disclosure, a reference signal is a signal known to both a base station and a mobile station, and each reference signal may be referred to as a reference signal (RS) or, in some cases, a pilot signal. A reference signal may be any of a DMRS, a Channel State Information-Reference Signal (CSI-RS), a Tracking Reference Signal (TRS), a Phase Tracking Reference Signal (PTRS), a Cell-specific Reference Signal (CRS), and a Sounding Reference Signal (SRS).

[0316] (Time Interval) In the present disclosure, the time resource unit is not limited to one or a combination of a slot and a symbol, and may be a time resource unit such as a frame, a superframe, a subframe, a slot, a time slot subslot, a minislot, or a time resource unit such as a symbol, an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) symbol, or other time resource unit. The number of symbols included in one slot is not limited to any number of symbols exemplified in the above embodiment(s), and may be other numbers of symbols.

[0317] (Frequency Band) The present disclosure may be applied to both licensed and unlicensed bands.

[0318] (communication) The present disclosure may be applied to any of communication between a base station and a terminal (Uu link communication), communication between terminals (sidelink communication), and vehicle to everything (V2X) communication. The channels in the present disclosure may be replaced with PSCCH, PSSCH, physical sidelink feedback channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0319] The present disclosure may also be applied to any of terrestrial networks and non-terrestrial networks (NTN: Non-Terrestrial Networks) using satellites or High Altitude Pseudo Satellites (HAPS). The present disclosure may also be applied to networks with large cell sizes and terrestrial networks with large delays compared to the symbol length or slot length, such as ultra-wideband transmission networks.

[0320] (Antenna port) An antenna port refers to a logical antenna (antenna group) formed by one or more physical antennas (multiple possible). That is, an antenna port does not necessarily refer to one physical antenna, but may refer to an array antenna formed by multiple antennas. For example, the number of physical antennas forming an antenna port is not defined, and instead, an antenna port is defined as the smallest unit by which a terminal can transmit a reference signal. Also, an antenna port may be defined as the smallest unit for multiplying the weighting of a precoding vector.

[0321] Furthermore, the various embodiments may be implemented by means of software modules which are executed by a processor or directly in hardware. A combination of software modules and hardware implementations may also be possible. The software modules may be stored in any kind of computer-readable storage medium, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc. Furthermore, it should be noted that individual features of the different embodiments may be the subject of another embodiment, either individually or in any combination.

[0322] Those skilled in the art will recognize that numerous changes and / or modifications may be made to the present disclosure as shown in the specific embodiments, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

1. determining a first plurality of slots including monitoring opportunities associated with a common search space of the downlink control channel; control circuitry that determines a second plurality of slots that include monitoring opportunities associated with a communications device specific search space of the downlink control channel; a receiver that monitors the downlink control channel in the first plurality of slots and the second plurality of slots; Equipped with the second plurality of slots is a portion of the first plurality of slots. Communication equipment.

2. The monitoring opportunity associated with the communications device-specific search space is determined based on information about the monitoring opportunity associated with the common search space. The communication device according to claim 1 .

3. The monitoring opportunities are included in the second plurality of slots in ascending order of index of the communication device-specific search space.

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

4. The first plurality of slots include at least one of a Type-1 common search space and a Type-3 common search space set by a dedicated message to the communication device. The communication device according to claim 1 .

5. The first plurality of slots includes at least one of a Type 1-PDCCH common search space, a Type 0, a Type 0A, and a Type 2 common search space that was not configured in a dedicated message to the communication device. The communication device according to claim 1 .

6. The first group of slots is contiguous in time and does not overlap. The communication device according to claim 1 .

7. The number X of the first plurality of slots is dependent on the subcarrier spacing used for the downlink control channel. The communication device according to claim 1 .

8. The number X is 4 for a subcarrier spacing of 480 kHz and 8 for a subcarrier spacing of 960 kHz. The communication device according to claim 7.

9. The minimum number Y of the second plurality of slots is 1, and the maximum number Y is half of the number X. The communication device according to claim 7.

10. The communication device receiving configuration information that configures a plurality of monitoring opportunities for the communication device to monitor the downlink control channel. The communication device according to claim 1 .

11. A method for a communication device, comprising: determining a first plurality of slots comprising monitoring opportunities associated with a common search space of a downlink control channel; determining a second plurality of slots comprising monitoring opportunities associated with a communications device specific search space of the downlink control channel; monitoring the downlink control channel in the first plurality of slots and the second plurality of slots; Including, the second plurality of slots is a portion of the first plurality of slots. method.

12. determining a first plurality of slots including monitoring opportunities associated with a common search space of the downlink control channel; control circuitry that determines a second plurality of slots that include monitoring opportunities associated with a communications device specific search space of the downlink control channel; a transmitter for transmitting the downlink control channel in the first plurality of slots and the second plurality of slots; Equipped with the second plurality of slots is a portion of the first plurality of slots. Base station.

13. A method for a base station, comprising: determining a first plurality of slots comprising monitoring opportunities associated with a common search space of a downlink control channel; determining a second plurality of slots comprising monitoring opportunities associated with a communications device specific search space of the downlink control channel; transmitting the downlink control channel in the first plurality of slots and the second plurality of slots; Including, the second plurality of slots is a portion of the first plurality of slots. method.

14. An integrated circuit for controlling processing of a communication device, the processing comprising: determining a first plurality of slots comprising monitoring opportunities associated with a common search space of a downlink control channel; determining a second plurality of slots comprising monitoring opportunities associated with a communications device specific search space of the downlink control channel; monitoring the downlink control channel in the first plurality of slots and the second plurality of slots; Including, the second plurality of slots is a portion of the first plurality of slots. Integrated circuit.

15. An integrated circuit for controlling processing of a base station, the processing comprising: determining a first plurality of slots comprising monitoring opportunities associated with a common search space of a downlink control channel; determining a second plurality of slots comprising monitoring opportunities associated with a communications device specific search space of the downlink control channel; transmitting the downlink control channel in the first plurality of slots and the second plurality of slots; Including, the second plurality of slots is a portion of the first plurality of slots. Integrated circuit.

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