Method, apparatus and computer program

Abstract

The invention provides equipment, a method, a device and a computer program. The apparatus comprises means for monitoring a physical downlink control channel using a first monitoring mode, determining to monitor the physical downlink control channel using a second monitoring mode based on a condition, determining an occurrence of at least one event related to a transmission from a user equipment, determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the occurrence of the at least one event, and monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

Description

[0001] This application is a divisional application of the invention patent application with the application date of October 23, 2020, the invention name of which is "Method, device and computer program" and the application number is 202080106632.X. Technical Field

[0002] The present application relates to a method, apparatus and computer program, and in particular, but not exclusively, to the impact of data activity on DCI-based power saving. Background Art

[0003] A communication system can be considered as a facility for enabling communication sessions between two or more entities, such as user terminals, base stations, and / or other nodes, by providing a carrier between the various entities involved in the communication path. For example, a communication system can be provided by means of a communication network and one or more compatible communication devices (also referred to as stations or user equipment) and / or application servers. A communication session may include, for example, communications for carrying data such as voice, video, electronic mail (email), text messages, multimedia, content data, time-sensitive network (TSN) streams, and / or data in industrial applications, such as critical system messages between actuators and controllers, transmission of critical sensor data (such as measurements, video feeds, etc.) to a control system, and the like. Non-limiting examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to data network systems such as the Internet.

[0004] In a wireless communication system, at least a portion of a communication session, for example, between at least two stations or between at least one station and at least one application server (e.g., for video), occurs over a wireless link. Examples of wireless systems include public land mobile networks (PLMNs) operating based on 3GPP radio standards, such as E-UTRA, New Air, satellite-based communication systems, and various wireless local area networks, such as wireless local area networks (WLANs). Wireless systems can typically be divided into cells and are therefore often referred to as cellular systems.

[0005] A user can access the communication system with the help of an appropriate communication device or terminal. The user's communication device may be referred to as a user equipment (UE) or user device. The communication device is provided with appropriate signal receiving and transmitting devices to enable communication, for example, to access the communication network or to communicate directly with other users. The communication device can access one or more carriers provided by a network such as a base station of a cell, and transmit and / or receive communications on one or more carriers. In carrier aggregation (CA), two or more carriers are combined into one channel. In dual connectivity (DC), two carriers from different sites are combined, that is, the user equipment can be dual (or multi) connected to two (or more) sites.

[0006] Communication systems and associated equipment typically operate according to a given standard or specification that specifies what the various entities associated with the system are allowed to do and how this should be achieved. The communication protocols and / or parameters used for the connection are also typically defined. One example of a communication system is UTRAN (3G radio). Other examples of communication systems are the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) based on E-UTRAN radio access technology, and the so-called 5G System (5GS) including 5G or Next Generation Core (NGC) and 5G access networks based on New Radio (NR) radio access technology. 5GS, including NR, is being standardized by the 3rd Generation Partnership Project (3GPP). Summary of the Invention

[0007] In a first aspect, a device is provided, comprising means for: monitoring a physical downlink control channel using a first monitoring mode, determining based on a condition whether to monitor the physical downlink control channel using a second monitoring mode, determining the occurrence of at least one event related to transmission from a user equipment, determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the occurrence of the at least one event, and monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0008] The condition may include at least one of an indication from a network node and a status of a timer.

[0009] At least one event related to the transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, initiation of a discontinuous reception retransmission timer, reception of downlink control information with a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connected mode discontinuous reception inactivity timer, triggering of transmission of reception of non-periodic channel state information or a sounding reference signal, providing a channel state information report, beam failure detection, and receiving a transmission configuration indication from a network node.

[0010] A scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0011] The first monitoring mode may include monitoring a physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0012] The second monitoring mode may be configured for the first time period, and the apparatus may include means for determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on how long the first time period remains.

[0013] The first monitoring mode may include monitoring a first set of search space sets having a first periodicity, and the second monitoring mode may include monitoring a second set of search space sets having a second periodicity, wherein the second periodicity is different from the first periodicity.

[0014] The apparatus may include means for monitoring a physical downlink control channel according to a configuration of a search space set group including a beam failure recovery search space in the event of beam failure detection, and otherwise monitoring according to a monitoring pattern prior to the event.

[0015] The apparatus may include means for determining whether to monitor a physical downlink control channel using a first monitoring mode or a second monitoring mode based on a second periodicity.

[0016] The apparatus may include means for determining whether to monitor a physical downlink control channel using a first monitoring mode or a second monitoring mode based on relative timing between an event and a condition.

[0017] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0018] The at least one cell may have triggered the scheduling request.

[0019] The at least one cell may be at least one cell allowed by the logical channel that triggers the scheduling request.

[0020] In a second aspect, a method is provided, comprising: monitoring a physical downlink control channel using a first monitoring mode; determining, based on a condition, to use a second monitoring mode to monitor the physical downlink control channel; determining the occurrence of at least one event related to transmission from a user equipment; determining, based on the occurrence of the at least one event, whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel; and monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0021] The condition may include at least one of an indication from a network node and a status of a timer.

[0022] At least one event related to the transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, initiation of a discontinuous reception retransmission timer, reception of downlink control information with a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connected mode discontinuous reception inactivity timer, triggering of transmission of reception of non-periodic channel state information or a sounding reference signal, providing a channel state information report, beam failure detection, and receiving a transmission configuration indication from a network node.

[0023] A scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0024] The first monitoring mode may include monitoring a physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0025] The second monitoring mode may be configured for the first time period, and the method may include determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on how long the first time period remains.

[0026] The first monitoring mode may include monitoring a first set of search space sets having a first periodicity, and the second monitoring mode may include monitoring a second set of search space sets having a second periodicity, wherein the second periodicity is different from the first periodicity.

[0027] The method may include, in the event of beam failure detection, monitoring a physical downlink control channel according to a configuration of a search space set group including a beam failure recovery search space, and otherwise monitoring according to a pre-event monitoring pattern.

[0028] The method may include determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the second periodicity.

[0029] The method may include determining whether to monitor a physical downlink control channel using a first monitoring mode or a second monitoring mode based on relative timing between the event and the condition.

[0030] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0031] The at least one cell may have triggered the scheduling request.

[0032] The at least one cell may be at least one cell allowed by the logical channel that triggers the scheduling request.

[0033] In a third aspect, an apparatus is provided, comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least:

[0034] Monitor a physical downlink control channel using a first monitoring mode; determine, based on conditions, to use a second monitoring mode to monitor the physical downlink control channel; determine the occurrence of at least one event related to transmission from the user equipment; determine, based on the occurrence of the at least one event, whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel; and monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0035] The condition may include at least one of an indication from a network node and a status of a timer.

[0036] At least one event related to the transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, initiation of a discontinuous reception retransmission timer, reception of downlink control information with a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connected mode discontinuous reception inactivity timer, triggering of transmission of reception of non-periodic channel state information or a sounding reference signal, providing a channel state information report, beam failure detection, and receiving a transmission configuration indication from a network node.

[0037] A scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0038] The first monitoring mode may include monitoring a physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0039] The second monitoring mode may be configured for a first time period, and the apparatus may be configured to determine whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on how long the first time period remains.

[0040] The first monitoring mode may include monitoring a first group of search space sets having a first periodicity, and the second monitoring mode may include monitoring a second group of search space sets having a second periodicity, wherein the second periodicity is different from the first periodicity.

[0041] The apparatus may be configured to monitor the physical downlink control channel according to a configuration of a search space set group including a beam failure recovery search space in the event of beam failure detection, and otherwise monitor according to a pre-event monitoring pattern.

[0042] The apparatus may be configured to determine whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the second periodicity.

[0043] The apparatus may be configured to determine whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on relative timing between the event and the condition.

[0044] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0045] The at least one cell may have triggered the scheduling request.

[0046] The at least one cell may be at least one cell allowed by the logical channel that triggers the scheduling request.

[0047] In a fourth aspect, a computer-readable medium comprising program instructions is provided, wherein the program instructions are used to cause an apparatus to perform at least the following: use a first monitoring mode to monitor a physical downlink control channel, determine based on conditions whether to use a second monitoring mode to monitor the physical downlink control channel, determine the occurrence of at least one event related to transmission from the user equipment, determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the occurrence of the at least one event, and use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the determination.

[0048] The condition may include at least one of an indication from a network node and a status of a timer.

[0049] At least one event related to the transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, initiation of a discontinuous reception retransmission timer, reception of downlink control information with a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connected mode discontinuous reception inactivity timer, triggering of transmission of reception of non-periodic channel state information or a sounding reference signal, providing a channel state information report, beam failure detection, and receiving a transmission configuration indication from a network node.

[0050] A scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0051] The first monitoring mode may include monitoring a physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0052] The second monitoring mode may be configured for the first time period, and the apparatus may be caused to perform determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on how long the first time period remains.

[0053] The first monitoring mode may include monitoring a first group of search space sets having a first periodicity, and the second monitoring mode may include monitoring a second group of search space sets having a second periodicity, wherein the second periodicity is different from the first periodicity.

[0054] In the case of beam failure detection, the apparatus may be caused to perform monitoring of the physical downlink control channel according to the configuration of the search space set group including the beam failure recovery search space, and otherwise perform monitoring according to the monitoring mode before the event.

[0055] The apparatus may be caused to perform, based on a second periodicity, determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode.

[0056] The apparatus may be caused to perform determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on relative timing between the event and the condition.

[0057] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0058] The at least one cell may have triggered the scheduling request.

[0059] The at least one cell may be at least one cell allowed by the logical channel that triggers the scheduling request.

[0060] In a fifth aspect, a non-transitory computer-readable medium is provided, comprising program instructions for causing an apparatus to at least perform the method according to the second aspect.

[0061] In the above, many different embodiments have been described. It should be understood that further embodiments can be provided by combining any two or more of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0063] Figure 1 A schematic diagram of an example 5G system is shown;

[0064] Figure 2 A schematic diagram of an example mobile communication device is shown;

[0065] Figure 3 A schematic diagram of an example control arrangement is shown;

[0066] Figure 4 A schematic diagram of the monitoring pattern for two SS collection groups is shown;

[0067] Figure 5 shows a flow chart of a method according to an example embodiment;

[0068] Figure 6 shows the signaling flow between the UE and the gNB according to an example embodiment;

[0069] Figure 7 shows the signaling flow between the UE and the gNB according to an example embodiment;

[0070] Figure 8 Schematic diagrams showing monitoring modes of an example embodiment and a conventional example;

[0071] Figure 9 A schematic diagram of a monitoring mode according to an example embodiment is shown. DETAILED DESCRIPTION

[0072] Before explaining the examples in detail, we will refer to Figures 1 to 3 Certain general principles of wireless communication systems and mobile communication devices are briefly explained to assist in understanding the technology behind the described examples.

[0073] An example of a suitable communication system is the 5G system (5GS). The network architecture in 5GS may be similar to that of Advanced LTE. The base stations of the NR system may be referred to as next generation Node Bs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and more refined QoS support, as well as some on-demand requirements for, for example, QoS levels to support user QoE. In addition, network-aware services and applications, as well as service- and application-aware networks, may bring changes to the architecture. These are all related to information-centric networking (ICN) and user-centric content delivery network (UC-CDN) approaches. NR may use multiple-input multiple-output (MIMO) antennas, many more base stations or nodes than LTE (the so-called small cell concept), which includes macro sites operating in cooperation with smaller sites, and may also use various radio technologies to achieve better coverage and enhanced data rates.

[0074] Future networks may utilize network function virtualization (NFV), a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operatively connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that use standard or general-purpose servers rather than custom hardware to run computer program code. Cloud computing or data storage may also be utilized. In radio communications, this may mean performing node operations at least in part in a server, host, or node operatively coupled to a remote radio head. Node operations may also be distributed across multiple servers, nodes, or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of LTE, or even not exist.

[0075] Figure 1 A schematic diagram of a 5G system (5GS) 100 is shown. The 5GS may include a user equipment (UE) 102 (also referred to as a communication device or terminal), a 5G radio access network (5GRAN) 104, a 5G core network (5GCN) 106, one or more application functions (AFs) 108, and one or more data networks (DNs) 110.

[0076] An example 5G core network (CN) includes functional entities. The 5GCN 106 may include one or more access and mobility management functions (AMFs) 112, one or more session management functions (SMFs) 114, an authentication server function (AUSF) 116, a unified data management (UDM) 118, one or more user plane functions (UPFs) 120, a unified data repository (UDR) 122, and / or a network exposure function (NEF) 124. The UPF is controlled by the SMF (session management function) that receives policies from the PCF (policy control function).

[0077] The CN is connected to the UE via a radio access network (RAN). The 5G RAN may include one or more gNodeB (GNB) distributed cell functions, which are connected to one or more gNodeB (GNDB) centralized cell functions. The RAN may include one or more access nodes.

[0078] The UPF (User Plane Function) whose role is called PSA (PDU Session Anchor) may be responsible for forwarding frames back and forth between the DN (Data Network) and the tunnel established over 5G to the UE that exchanges services with the DN.

[0079] Now refer to Figure 2 Describing in more detail possible mobile communication devices, Figure 2A schematic, partially cutaway view of a communication device 200 is shown. Such communication devices are generally referred to as user equipment (UE) or terminals. Suitable mobile communication devices can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mobile device, such as a mobile phone or so-called "smartphone," a computer provided with a wireless interface card or other wireless interface facility (e.g., a USB dongle), a personal data assistant (PDA), or a tablet computer provided with wireless communication capabilities, or any combination of these or similar devices. For example, a mobile communication device can provide communication services such as voice, email, text messaging, multimedia, and other data used to carry communications. Thus, a wide range of services can be provided and configured to users via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communications or multimedia services, or simply access to a data communications network system, such as the Internet. Broadcast or multicast data can also be provided to users. Non-limiting examples of content include downloads, television and radio programs, videos, advertisements, various alerts, and other information.

[0080] The mobile device is typically provided with at least one data processing entity 201, at least one memory 202 and possibly other components 203 for software and hardware assistance in performing the tasks it is designed to perform, including controlling access to and communicating with access systems and other communication devices. Data processing, storage and other related control devices may be provided on appropriate circuit boards and / or in chipsets. This feature is indicated by reference numeral 204. The user may control the operation of the mobile device with the aid of a suitable user interface such as a keyboard 205, voice commands, a touch-sensitive screen or touchpad, or a combination thereof. A display 208, a speaker and a microphone may also be provided. In addition, the mobile communication device may include appropriate connectors (wired or wireless) to other devices and / or for connecting external accessories such as hands-free devices to other devices.

[0081] The mobile device 200 may receive signals over the air or radio interface 207 via suitable means for receiving, and may transmit signals via suitable means for transmitting radio signals. Figure 2 In FIG, the transceiver arrangement is schematically represented by block 206. The transceiver arrangement 206 may be provided, for example, by a radio component and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0082] Figure 3An example embodiment of a control device for a communications system is shown, for example, coupled to and / or used to control a station accessing the system, such as a RAN node, e.g., a base station, eNB, or gNB, a relay node, or a core network function, such as an AMF / SMF, or a server or host. The method can be implemented in a single control device or across multiple control devices. The control device can be integrated with a node or module of the core network or RAN, or located within the core network or externally. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device can be another network element, such as a radio network controller or spectrum controller. In some embodiments, each base station may have such a control device in addition to the control device provided in the radio network controller. The control device 300 may be arranged to provide control of communications within the service area of ​​the system. The control device 300 includes at least one memory 301, at least one data processing unit 302, 303, and an input / output interface 304. Via this interface, the control device can be coupled to a receiver and transmitter of the base station. The receiver and / or transmitter can be implemented as a radio front end or a remote radio head.

[0083] The following is related to the REL17 work item on UE energy saving enhancements for NR (RP-200338), where DCI-based power saving is listed as one of the goals:

[0084] a) Study and specify, if agreed, extensions to Rel-16 DCI based power saving adaptation during DRX active time of active BWP, including reduction of PDCCH monitoring when C-DRX is configured [RAN1]

[0085] Note: Power saving solutions available for Rel-15 and Rel-16 shall be supported by the UE and included in the evaluation. RAN1 will request RAN2 to confirm that the power saving solutions available for Rel-15 and Rel-16 are correctly utilized.

[0086] RAN1 has already agreed to a list of options to consider in its previous meeting, RAN1#102e. The primary mechanisms are physical downlink control channel (PDCCH) skip indication based on downlink control information (DCI) and search space (SS) set group switching based on DCI and timers. UL transmissions, such as scheduling requests (SRs) and configuration grants (CGs), are also mentioned.

[0087] Recommendation 8: The following triggering scheme can be considered for DCI-based energy saving adaptation during DRX active time:

[0088] Scheduling DCI

[0089] o The indication of PDCCH monitoring behavior adaptation can be

[0090] o Explicit / implicit indication by scheduling DCI

[0091] o PDCCH monitoring adaptive joint indication, with

[0092] Inter-slot scheduling defined in Rel-16

[0093] Scell ​​sleep

[0094] [SS set group switching defined in Rel-16]

[0095] o The scheduling DCI used to indicate PDCCH monitoring behavior adaptation can be DCI format x_1 / x_2

[0096] o DCI format x_1

[0097] o DCI format x_2

[0098] o Enhancements to retransmission handling

[0099] o Adaptation is applied only after HARQ ACK conditions are met

[0100] o Apply adaptation immediately after DCI indication, but start a timer to handle retransmissions if needed

[0101] Non-scheduled DCI

[0102] o Group common DCI, such as SS set group handover defined in Rel-16

[0103] o Clearly stated by DCI

[0104] o PDCCH monitoring adaptive joint indication, with

[0105] Inter-slot scheduling defined in Rel-16

[0106] o DCI format 2_6, used to indicate adaptation of PDCCH monitoring during active time, and it should extend the DCI where the ps RNTI is received during active time

[0107] o Extend DCI format 2_6 to indicate adaptation of PDCCH monitoring during the next DRX cycle within the activation time

[0108] o Unicast non-scheduled DCI, such as DCI formats 0_1 and 1_1 for case 2 sleep indication [Timer-based adaptation to adapt PDCCH monitoring behavior, including skipping or monitoring set adaptation,

[0109] o A timer, such as a timer similar to the Time Search Space Switch Timer-r16, may trigger the UE to switch between search space set groups 0 and 1]

[0110] -UL transmission, such as SR / CG

[0111] With the configured search space groups, the gNB can adapt the UE's PDCCH monitoring behavior (e.g., SS set configuration), and this adaptation between groups can reduce or increase UE PDCCH monitoring (e.g., via different SS periodicity). This can achieve power savings.

[0112] The functionality of R16 SS switching can be summarized as follows:

[0113] Introducing NR-U SS group (search space group) switching configuration

[0114] One or more SS groups form GROUP0

[0115] One or more SS groups form GROUP1

[0116] Some sets of search spaces may remain ungrouped and always monitored

[0117] Switching behavior

[0118] GC-PDCCH 1-bit switching group, or

[0119] · Detection of PDCCH in GROUP0 triggering a change from GROUP0 to GROUP1

[0120] COT triggers the change from GROUP1 to GROUP0

[0121] Timer-based change GROUP1->GROUP 0

[0122] Multiple cells can be grouped and switched synchronously

[0123] Figure 4 An example of how to configure monitoring on two cells for a UE is shown. The gNB may configure synchronized handover for the Pcell and the Scell ​​and the UE does not monitor on the Scell ​​if Group 1 is active for the configured Pcell+Scell ​​cell group.

[0124] With DCI-based PDCCH skipping, the network (NW) can indicate to the UE that it can skip monitoring PDCCH for specific periods. With SS set group switching, the NW can switch between different SS set groups with different pre-configured PDCCH opportunity periodicities (this also includes zero monitoring if the SS set is empty), or the UE can autonomously change SS set groups based on a timer. How this decision is made depends on the NW implementation, for example, based on whether there is data available for transmission, the latency requirements for transmitting that data, or the scheduler algorithm.

[0125] Regarding the interaction with the current discontinuous reception (DRX) mechanism, the general assumption is that PDCCH skipping / SS set group switching works on top of L2 connected mode-DRX (C-DRX), so with PDCCH skipping, the UE may not monitor PDCCH even during the active time according to DRX, and the NW can switch to a different SS set without affecting the DRX timer.

[0126] When the network (NW) sends a PDCCH skip command or an SS set group switch command (or switches SS set groups based on a timer), the NW will not be able to take into account the activity on the UE side. If uplink (UL) / downlink (DL) activity occurs after the PDCCH skip command and the timer for skipping is running or after the SS set is switched to a less frequent PDCCH occasion configuration, then, for example, if the UL activity is an SR triggered by high-priority data or the DL data is high-priority data, it may be undesirable for the UE to monitor PDCCH only after the skip timer expires or after a delay in the SS set switch case (waiting 2 time slots for the first monitoring position of the low-periodicity SS group after the transmitted PDCCH+gNB).

[0127] In legacy LTE and NR DRX, the UE moves to active time after SR transmission, and the UE monitors PDCCH for random access response regardless of DRX.

[0128] The interaction between PDCCH skipping and random access channel (RACH) has been considered, and it has been proposed to determine whether to use PDCCH skipping based on different conditions, such as NW initiated or UE initiated, random access (RA) triggered, etc.

[0129] The interaction between PDCCH skipping and CG has been considered, and it has been proposed to interrupt skipping or not, depending on the priority of the data to be transmitted.

[0130] The interaction between SS group switching cross-slot scheduling and DRX is considered.

[0131] Figure 5A flow chart of a method according to an example embodiment is shown.

[0132] In a first step S1 , the method comprises monitoring a Physical Downlink Control Channel (PDCCH) using a first monitoring pattern.

[0133] In a second step S2, the method comprises determining based on a condition to monitor the PDCCH using a second monitoring pattern.

[0134] In a third step S3, the method comprises determining the occurrence of at least one event related to transmissions from the user equipment.

[0135] In a fourth step S4, the method comprises determining whether to monitor the PDCCH using the first monitoring mode or the second monitoring mode based on the occurrence of the at least one event.

[0136] In a fifth step S5, the method comprises monitoring the PDCCH using the first monitoring pattern or the second monitoring pattern based on the determination.

[0137] The condition may include at least one of an indication from a network node and a status of a timer.

[0138] The first monitoring mode may include monitoring the Physical Downlink Control Channel, and the second monitoring mode may include not performing PDCCH monitoring for a period of time, ie, PDCCH skipping. In this case, the condition may be, for example, a DCI-based PDCCH skipping indication as described above.

[0139] Alternatively, the first monitoring mode may include monitoring a first search space set group with a first periodicity, and the second monitoring mode may include monitoring a second search space set group with a second periodicity, where the second periodicity is different from the first periodicity, i.e., SS set group switching as described above. In this case, at least one search space set of one group has a different periodicity than at least one search space set of another group, and the other group may be a null set.

[0140] In this case, the condition may be, for example, an indication from the NW to switch between different SS set groups with different preconfigured PDCCH opportunity periodicities (this also includes zero monitoring if the SS group is empty), or the UE may autonomously change the SS group based on a timer.

[0141] The method proposes events (or activities) related to transmissions from the user equipment that take precedence over the PDCCH skip command, or when SS set group M (with high monitoring periodicity) is active, in which case the UE stops the skip timer and starts monitoring PDCCH, or switches to a predefined SS set group N (N is different from M, preferably with lower monitoring periodicity).

[0142] This approach can provide low latency for high priority UL / DL activities even if PDCCH skipping and / or SS set group switching is triggered.

[0143] The at least one event may include triggering a scheduling request. This event may include a scheduling request triggered by a logical channel with a priority higher than a certain threshold. Whether the second monitoring mode is used may depend on the logical channel (LCH) that triggers the scheduling request, because different LCHs may have different thresholds for triggering a scheduling request. In other words, the event is prioritized only when the scheduling request is triggered by an LCH with a priority higher than a certain threshold.

[0144] Whether to use the first monitoring mode or the second monitoring mode may depend on how much time is left in the current skip period, or how long the current periodicity of the SS set is.

[0145] The method may include determining whether to use a first monitoring mode or a second monitoring mode to monitor the physical downlink control channel based on the relative timing between the event and the condition. For example, whether to use the first monitoring mode or the second monitoring mode may depend on whether the event occurs before or after the PDCCH skip command. For example, if it occurs X time slots before the PDCCH-command, the skip is applied because it is a NW decision; if the event occurs after, the skip command is not applied (i.e., the UE stops the skip timer). Similarly, in another example embodiment, if the event occurs X time slots before the SS set group switch, the UE does not automatically switch to another SS set group. If the event occurs after, the UE switches to another predefined SS set group.

[0146] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell. The at least one cell may be a cell that triggers SR or a cell that is allowed by the LCH that triggers SR.

[0147] In an example embodiment, SS set group switching can be limited to a cell or a group of SS set switching cells that includes the allowed cells for the LCH that triggers the SR. Similarly, disabling PDCCH skipping can also be limited to a given cell, such as a cell that is allowed by the LCH that triggers the SR. SS set group switching can be performed at the first DL slot boundary that is X symbols after the UL slot boundary that includes the PUCCH resource containing the SR, or after the last symbol of the PUCCH resource containing the SR.

[0148] The SS set group can change from group 0 to group 1, or from group N to group M, where M is the SS set group ID specially configured by the NW.

[0149] The event may include transmitting a Hybrid Automatic Repeat Request (HARQ) negative acknowledgement (NACK) to the NW, or starting a DRX retransmission timer if the initiation of the DRX retransmission timer occurs after a skip command or when SS set group switch group M is active.

[0150] This event may include receiving a DCP (DCI with a cyclic redundancy check (CRC) scrambled by a power save radio network temporary identifier (PS-RNTI). For example, when a DCP (e.g., DCI format 2_6) is received that wakes up the associated OnDuration timer, if the DCP is received after a PDCCH skip command that starts the skip timer, the UE stops the skip timer and starts monitoring the PDCCH. This means that even if the PDCCH skip timer is running, the UE monitors the DCP to allow the NW to return the UE to monitoring the PDCCH when high priority DL data becomes available for transmission.

[0151] This event may include the expiration of a C-DRX inactivity timer. For example, when the C-DRX inactivity timer expires, the UE stops the skip timer and starts monitoring according to the C-DRX configuration. This means that the skip timer does not affect the inactivity timer, such as the upcoming activity time after expiration based on the duration of the short DRX cycle.

[0152] The event may include receiving a trigger for transmitting aperiodic channel state information (CSI) on a physical uplink shared channel (PUSCH) or an aperiodic sounding reference signal (SRS). The event may be determined for a specific trigger state for aperiodic CSI transmission.

[0153] The event may include providing a CSI report. The CSI report may include periodic, aperiodic, or semi-persistent reporting. The CSI report may be sent on uplink signaling resources such as PUCCH / PUSCH.

[0154] The event may include indicating beam failure detection (BFD) and starting to monitor the recovery SS (which may be indicated by the recovery search space Id). In the case of BFD, the method may include monitoring the physical downlink control channel according to the configuration of the search space set group including the beam failure recovery search space, otherwise monitoring according to the monitoring mode before the event.

[0155] The event may include a Transmit Configuration Indication (TCI) from the network node. For example, upon receiving a Medium Access Control (MAC) Control Element (CE) activation command for a TCI state or TCI state DCCH ToAddList and / or TCI state PDCCH ToReleaseList for at least one serving cell, such as a PCell or at least one Scell, the active SS set group is changed to an SS set group including a Beam Failure Recovery (BFR) SS or an SS set group configured by the NW (if any), otherwise (if the BFR SS belongs to the active group or the BFR SS does not belong to any group), the SS group is not changed.

[0156] In one embodiment, the skip timer may be stopped and monitoring of the PDCCH may begin at the first DL slot boundary (or switch to a predefined SS set group) N symbols / slots or milliseconds after the UL slot in which the proposed uplink activity has occurred. In one example, N=0, 1, 2. In one example, the UL activity may be the transmission of any uplink signal / channel described herein (such as SR / CSI on PUCCH or CSI on PUSCH).

[0157] Figure 6 A flow chart of a method for PDCCH skipping according to an example embodiment is shown.

[0158] The UE is in active time and receives an indication from the gNB to skip PDCCH monitoring for Xms. Upon receiving this indication, the UE stops monitoring PDCCH and starts a timer for Xms.

[0159] During time X, uplink data arrives in the UE's buffer and the UE sends an SR. In response to sending the SR, the UE stops the timer and starts monitoring the PDCCH.

[0160] Figure 7 A flow chart of an SS group switching method according to an example embodiment is shown.

[0161] The UE is in active time and receives an indication from the gNB to switch to SS set group N. Upon receiving the indication, the UE monitors the PDCCH infrequently according to the group N configuration.

[0162] When the UE monitors the PDCCH according to the group N configuration, uplink data arrives in the UE's buffer and the UE transmits an SR. In response to sending the SR, the UE switches to the SS set group M.

[0163] Figure 8 shows the comparison between the proposed scheme and the traditional scheme. We assume Figure 4Consider the monitoring mode in Figure 1 and the SR transmitted by the UE in slot #5. In the conventional scheme, the gNB can schedule the UL grant only in slot #10 (based on the large periodicity of SS group 0), resulting in a delay in data scheduling. With our proposal, the SR-to-data time can be reduced (by 5 slots in this example).

[0164] Figure 9 The proposed mechanism for implicit cross-CC SS group change is shown. Here, we assume that no synchronous handover is configured between Pcell and Scell.

[0165] When the gNB wants to start scheduling on the Scell ​​due to data arrival, it can trigger A-CSI reporting in the PUSCH on the Pcell for the Scell ​​and thus switch to more frequent monitoring on the Scell.

[0166] This method can be found in the reference Figure 2 The method is implemented in the user equipment described.

[0167] A device may include a device for: monitoring a physical downlink control channel using a first monitoring mode, determining based on a condition to use a second monitoring mode to monitor the physical downlink control channel, a device for determining the occurrence of at least one event related to transmission from a user equipment, determining based on the occurrence of the at least one event whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel, and monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0168] It should be understood that these devices may include or be coupled to other units or modules, such as radio components or radio heads for transmission and / or reception. Although the device is described as one entity, the different modules and memories may be implemented in one or more physical or logical entities.

[0169] Note that while embodiments have been described with respect to LTE and 5GS, similar principles may be applied to other networks and communication systems. Thus, while certain embodiments have been described above by way of example with reference to certain example architectures of wireless networks, technologies, and standards, the embodiments may be applied to any other suitable form of communication system in addition to the communication systems shown and described herein.

[0170] It is also noted herein that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0171] In general, the various example embodiments may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other illustrations, it should be clearly understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or a controller or other computing device, or some combination thereof.

[0172] Embodiments of the present invention may be implemented by computer software executable by a data processor of a mobile device, for example, in a processor entity, or by hardware, or by a combination of software and hardware. Also referred to as program products, computer software or programs, including software routines, applets, and / or macros, may be stored in any device-readable data storage medium and include program instructions for performing specific tasks. A computer program product may include one or more computer-executable components that are configured to perform the embodiments when the program is run. The one or more computer-executable components may be at least one software code or portion thereof.

[0173] Also in this regard, it should be noted that any blocks of the logic flow as shown in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs. Physical media are non-transitory media.

[0174] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. As non-limiting examples, the data processor may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an FPGA, a gate-level circuit, and a processor based on a multi-core processor architecture.

[0175] Example embodiments of the present invention may be practiced in various components such as integrated circuit modules. Generally speaking, the design of integrated circuits is a highly automated process. Complex and powerful software tools are available to convert a logic-level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0176] The foregoing description has provided by way of non-limiting examples a complete and informative description of the exemplary embodiments of the present invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. Nevertheless, all such and similar modifications of the teachings of this invention will still fall within the scope of the invention as defined in the appended claims. Indeed, further embodiments exist comprising combinations of one or more embodiments with any other embodiments previously discussed.

Claims

1. A device comprising means for performing the following at a user equipment: monitoring a physical downlink control channel using a first monitoring mode; Based on a condition, determining to use a second monitoring mode to monitor the physical downlink control channel; determining an occurrence of at least one event associated with a transmission from the user equipment; determining, based on the occurrence of the at least one event, whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode; as well as Based on the determination, the physical downlink control channel is monitored using the first monitoring mode or the second monitoring mode.

2. The device according to claim 1, wherein The condition includes at least one of an indication from a network node and a status of a timer.

3. The apparatus according to claim 1 or claim 2, wherein: The at least one event related to transmission comprises at least one of: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, activation of a discontinuous reception retransmission timer, reception of downlink control information with a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiry of a connected mode discontinuous reception inactivity timer, reception of a trigger for transmitting a non-periodic channel state information or a sounding reference signal, provision of a channel state information report, beam failure detection, and reception of a transmission configuration indication from a network node.

4. The device according to claim 3, wherein The scheduling request is triggered by a logical channel whose priority is higher than a given threshold.

5. The apparatus according to any one of claims 1 to 4, wherein The first monitoring mode includes monitoring the physical downlink control channel, and the second monitoring mode includes not performing physical downlink control channel monitoring.

6. The device according to claim 5, wherein The second monitoring mode is configured for a first time period and includes means for determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on how long the first time period remains.

7. The apparatus according to any one of claims 1 to 4, wherein: The first monitoring mode includes monitoring a first search space set group with a first periodicity, and the second monitoring mode includes monitoring a second search space set group with a second periodicity, wherein the second periodicity is different from the first periodicity.

8. The apparatus according to claim 7, when dependent on claim 3, comprises means for monitoring the physical downlink control channel according to the configuration of the search space set group including the beam failure recovery search space in the event of beam failure detection, otherwise monitoring according to the monitoring mode before the event.

9. The apparatus of claim 7, comprising means for determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the second periodicity.

10. The apparatus according to any one of claims 1 to 9, comprising means for determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the relative timing between the event and the condition.

11. The apparatus according to any one of claims 1 to 10, wherein The monitoring mode is applied to at least one cell or a cell group including the at least one cell.

12. Apparatus according to claim 11, when dependent on claim 3, wherein said at least one cell triggers said scheduling request.

13. The apparatus according to claim 12, wherein The at least one cell is at least one cell allowed by the logical channel that triggers the scheduling request.

14. A method comprising: monitoring a physical downlink control channel using a first monitoring mode; Based on a condition, determining to use a second monitoring mode to monitor the physical downlink control channel; determining an occurrence of at least one event associated with a transmission from the user equipment; determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the occurrence of the at least one event; as well as Based on the determination, the physical downlink control channel is monitored using the first monitoring mode or the second monitoring mode.

15. An apparatus comprising: at least one processor and at least one memory including computer program code configured to, with the at least one processor, cause the apparatus to at least: monitoring a physical downlink control channel using a first monitoring mode; Based on a condition, determining to use a second monitoring mode to monitor the physical downlink control channel; determining an occurrence of at least one event associated with a transmission from the user equipment; determining whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the occurrence of the at least one event; as well as Based on the determination, the physical downlink control channel is monitored using the first monitoring mode or the second monitoring mode.

16. A computer-readable medium comprising program instructions for causing an apparatus to perform at least the following operations: monitoring a physical downlink control channel using a first monitoring mode; Based on a condition, determining to use a second monitoring mode to monitor the physical downlink control channel; determining an occurrence of at least one event associated with a transmission from the user equipment; determining, based on the occurrence of the at least one event, whether to monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode; as well as Based on the determination, the physical downlink control channel is monitored using the first monitoring mode or the second monitoring mode.

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