Method, apparatus, and computer program

Abstract

A device is provided, the device including means for: monitoring a physical downlink control channel using a first monitoring mode, determining based on a condition to monitor the physical downlink control channel using a second monitoring mode, determining the occurrence of at least one event related to a 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.

Description

Technical Field

[0001] The present application relates to a method, an apparatus, and a computer program, and in particular but not exclusively, to the impact of data activities on DCI-based power saving. Background Art

[0002] A communication system can be regarded as a facility that enables a communication session between two or more entities such as user terminals, base stations, and / or other nodes by providing carriers between 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 can include, for example, communication for carrying data for communication, such as voice, video, 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, transmitting critical sensor data (such as measurements, video feeds, etc.) to a control system, etc. Non-limiting examples of the services provided include two-way or multi-way calls, data communication, or multimedia services, and access to a data network system such as the Internet.

[0003] In a wireless communication system, at least a part of a communication session, for example, between at least two stations or between at least one station and at least one (e.g., for video) application server, 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 Radio, satellite-based communication systems, and different wireless local area networks, such as wireless local area network (WLAN). Wireless systems are typically divided into cells and are therefore often referred to as cellular systems.

[0004] A user can access a communication system by means of an appropriate communication device or terminal. The user's communication device can be referred to as a user equipment (UE) or user device. The communication device is provided with appropriate signal receiving and transmitting means to enable communication, for example, to access a 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 communication 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.

[0005] Communication systems and related devices typically operate according to a given standard or specification that defines what the various entities associated with the system are allowed to do and how they should be implemented. Communication protocols and / or parameters used for connections are also typically defined. An 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 the E-UTRAN radio access technology, and the so-called 5G system (5GS) that includes 5G or Next Generation Core (NGC) and a 5G access network based on the New Radio (NR) radio access technology. The 5GS, including NR, is being standardized by the 3rd Generation Partnership Project (3GPP). Summary of the Invention

[0006] In a first aspect, there is provided an apparatus comprising means for: monitoring a physical downlink control channel using a first monitoring mode, determining, based on a condition, to monitor the physical downlink control channel using a second monitoring mode, determining the occurrence of at least one event related to a 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.

[0007] The condition may include at least one of an indication from a network node and a status of a timer.

[0008] The 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, start of a discontinuous reception retransmission timer, reception of downlink control information having a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connection mode discontinuous reception inactivity timer, triggering of a transmission for receiving an aperiodic 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.

[0009] The scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0010] The first monitoring mode may include monitoring the physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0011] The second monitoring mode may be configured for a first time period, and the apparatus may include 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 much time remains in the first time period.

[0012] The first monitoring mode may include monitoring a first set of search spaces having a first periodicity, and the second monitoring mode may include monitoring a second set of search spaces having a second periodicity, where the second periodicity is different from the first periodicity.

[0013] The device may include means for monitoring the physical downlink control channel according to the configuration of a set of search spaces including a beam failure recovery search space in case of beam failure detection, or otherwise monitoring according to the monitoring mode prior to the event.

[0014] The device may include 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 second periodicity.

[0015] The device may include 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 an event and a condition.

[0016] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0017] The at least one cell may have triggered the scheduling request.

[0018] The at least one cell may be at least one cell allowed by the logical channel that triggered the scheduling request.

[0019] In a second aspect, a method is provided, including: 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 the occurrence of at least one event related to a transmission from a user equipment; determining 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 monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0020] The condition may include at least one of an indication from a network node and the status of a timer.

[0021] The 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 acknowledgment, start of a discontinuous reception retransmission timer, reception of downlink control information having a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connection mode discontinuous reception inactivity timer, triggering of transmission of reception of an aperiodic 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.

[0022] A scheduling request may be triggered by a logical channel with a priority higher than a given threshold.

[0023] 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.

[0024] The second monitoring mode may be configured for a first time period, and the method may include determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on how much time remains in the first time period.

[0025] The first monitoring mode may include monitoring a first set of search spaces with a first periodicity, and the second monitoring mode may include monitoring a second set of search spaces with a second periodicity, where the second periodicity is different from the first periodicity.

[0026] The method may include, in the case of beam failure detection, monitoring the physical downlink control channel according to the configuration of a set of search spaces including a beam failure recovery search space, and otherwise monitoring according to the monitoring mode before the event.

[0027] The method may include determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the second periodicity.

[0028] The method may include 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 an event and a condition.

[0029] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0030] The at least one cell may have triggered the scheduling request.

[0031] The at least one cell may be at least one cell allowed by the logical channel that triggered the scheduling request.

[0032] In a third aspect, there is provided an apparatus, including: 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, by using the at least one processor, cause the apparatus to at least:

[0033] Monitor a physical downlink control channel using a first monitoring mode; determine to monitor the physical downlink control channel using a second monitoring mode based on a condition; determine the occurrence of at least one event related to a 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 monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0034] The condition may include at least one of an indication from a network node and a status of a timer.

[0035] At least one event related to a transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, start of a discontinuous reception retransmission timer, reception of downlink control information having a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connection mode discontinuous reception inactivity timer, triggering of a transmission for receiving an aperiodic 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.

[0036] A scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0037] The first monitoring mode may include monitoring the physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0038] The second monitoring mode may be configured for a first time period, and the apparatus may be configured to determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on how much time remains in the first time period.

[0039] The first monitoring mode may include monitoring a first set of search spaces having a first periodicity, and the second monitoring mode may include monitoring a second set of search spaces having a second periodicity, where the second periodicity is different from the first periodicity.

[0040] The apparatus may be configured to, in the case of beam failure detection, monitor the physical downlink control channel according to a configuration of a set of search spaces including a beam failure recovery search space, and otherwise monitor according to the monitoring mode prior to the event.

[0041] The apparatus may be configured to determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the second periodicity.

[0042] The apparatus may be configured to determine whether to use a first monitoring mode or a second monitoring mode to monitor a physical downlink control channel based on a relative timing between an event and a condition.

[0043] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0044] The at least one cell may have triggered the scheduling request.

[0045] The at least one cell may be at least one cell allowed by a logical channel that triggers a scheduling request.

[0046] In a fourth aspect, there is provided a computer-readable medium including program instructions for causing an apparatus to at least perform the following: 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 the user equipment, determining 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 monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination.

[0047] The condition may include at least one of an indication from a network node and a status of a timer.

[0048] The at least one event related to a transmission may include at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgment, start of a discontinuous reception retransmission timer, reception of downlink control information having a cyclic redundancy check scrambled by a power saving radio network temporary identifier, expiration of a connection mode discontinuous reception inactivity timer, triggering of a transmission for receiving an aperiodic 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.

[0049] The scheduling request may be triggered by a logical channel having a priority higher than a given threshold.

[0050] The first monitoring mode may include monitoring the physical downlink control channel, and the second monitoring mode may include not performing physical downlink control channel monitoring.

[0051] The second monitoring mode may be configured for a first time period, and the apparatus may be caused to perform a determination of whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on how much of the first time period remains.

[0052] The first monitoring mode may include monitoring a first set of search spaces having a first periodicity, and the second monitoring mode may include monitoring a second set of search spaces having a second periodicity, where the second periodicity is different from the first periodicity.

[0053] In the case of beam failure detection, the device may be made to perform monitoring of the physical downlink control channel according to the configuration of a set of search spaces including a beam failure recovery search space, or otherwise perform monitoring according to the monitoring mode before the event.

[0054] The device may be made to perform a determination of whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the second periodicity.

[0055] The device may be made to perform a determination of 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 an event and a condition.

[0056] The monitoring mode may be applied to at least one cell or a cell group including the at least one cell.

[0057] The at least one cell may have triggered the scheduling request.

[0058] The at least one cell may be at least one cell allowed by the logical channel that triggered the scheduling request.

[0059] In a fifth aspect, there is provided a non-transitory computer-readable medium including program instructions for causing a device to perform at least the method according to the second aspect.

[0060] Above, many different embodiments have been described. It should be understood that further embodiments may be provided by a combination of any two or more of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0062] Figure 1 A schematic diagram of an example 5G system is shown;

[0063] Figure 2 A schematic diagram of an example mobile communication device is shown;

[0064] Figure 3 A schematic diagram of an example control device is shown;

[0065] Figure 4 A schematic diagram of the monitoring modes of two SS sets is shown;

[0066] Figure 5 A flowchart of a method according to an example embodiment is shown;

[0067] Figure 6 Shows the signaling flow between the UE and the gNB according to an example embodiment;

[0068] Figure 7 Shows the signaling flow between the UE and the gNB according to an example embodiment;

[0069] Figure 8 Shows a schematic diagram of the monitoring modes of an example embodiment and a conventional example;

[0070] Figure 9 Shows a schematic diagram of the monitoring mode according to an example embodiment. Detailed implementation

[0071] Before explaining the examples in detail, reference will be made to Figures 1 to 3 Briefly explain some general principles of wireless communication systems and mobile communication devices to assist in understanding the technology behind the examples.

[0072] 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 in 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 finer QoS support, as well as some requirements for QoS levels for supporting the QoE of users. 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 (the so-called small cell concept), which include macro sites operating in cooperation with smaller sites, and may also use various radio technologies to achieve better coverage and enhanced data rates.

[0073] Future networks may utilize network function virtualization (NFV), which is 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. Virtualized network functions (VNFs) may include one or more virtual machines that run computer program code using standard or general-purpose type servers instead of custom hardware. Cloud computing or data storage may also be utilized. In radio communication, this may mean that node operations are performed at least partially in servers, hosts, or nodes that are operatively coupled to remote radio heads. It is also possible for node operations to be distributed among multiple servers, nodes, or hosts. It should also be understood that the labor distribution between core network operations and base station operations may be different from that of LTE, or may even not exist.

[0074] Figure 1 Shows a schematic diagram of a 5G system (5GS) 100. The 5GS may include a user equipment (UE) 102 (which may also be 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 (AF) 108, and one or more data networks (DN) 110.

[0075] An example 5G core network (CN) includes functional entities. The 5GCN 106 may include one or more access and mobility management functions (AMF) 112, one or more session management functions (SMF) 114, an authentication server function (AUSF) 116, a unified data management (UDM) 118, one or more user plane functions (UPF) 120, a unified data repository (UDR) 122, and / or a network exposure function (NEF) 124. The UPF is controlled by an SMF (session management function) that receives policies from a PCF (policy control function).

[0076] The CN is connected to the UE via a radio access network (RAN). The 5GRAN may include one or more gNodeB (GNB) distributed cell functions, which are connected to one or more g NodeB (GNDB) centralized cell functions. The RAN may include one or more access nodes.

[0077] A 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 through 5G to the UE that exchanges traffic with the DN.

[0078] Now will refer to Figure 2 more specifically describe possible mobile communication devices, Figure 2Shows a schematic partial cross-sectional view of a communication device 200. Such a communication device is commonly referred to as a user equipment (UE) or a terminal. A suitable mobile communication device can be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include a mobile station (MS) or a mobile device, such as a mobile phone or a so-called "smartphone", a computer provided with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, or any combination of these or similar devices. For example, a mobile communication device can provide communications for carrying data such as voice, email, text messages, multimedia, etc. Thus, many services can be provided to and equipped for the user via the user's communication device. Non-limiting examples of these services include two-way or multi-way calls, data communications or multimedia services, or simply accessing a data communication network system such as the Internet. Broadcast or multicast data can also be provided to the user. Non-limiting examples of content include downloads, television and radio programs, videos, advertisements, various alerts and other information.

[0079] A mobile device is typically provided with at least one data processing entity 201, at least one memory 202 and other possible components 203 for software and hardware assisted execution of the tasks it is designed to perform, including controlling access to and communicating with access systems and other communication devices. The data processing, storage and other related control devices can be provided on a suitable circuit board and / or in a chipset. This feature is denoted by the reference numeral 204. The user can control the operation of the mobile device by means of a suitable user interface such as a keyboard 205, voice commands, a touch-sensitive screen or a touchpad, combinations thereof, etc. A display 208, a speaker and a microphone can also be provided. In addition, a mobile communication device can include a suitable connector (wired or wireless) to other devices and / or for connecting external accessories such as a hands-free device to other devices.

[0080] The mobile device 200 can receive signals via a suitable device for reception over the air or a radio interface 207, and can transmit signals via a suitable device for transmitting radio signals. In Figure 2 it, the transceiver device is schematically represented by the block 206. The transceiver device 206 can be provided, for example, by radio components and an associated antenna arrangement. The antenna arrangement can be arranged inside or outside the mobile device.

[0081] Figure 3Shows an example embodiment of a control device for a communication system, such as a control device coupled to and / or for controlling a station accessing the system, such as a RAN node, e.g., a base station, eNB or gNB, relay node or core network function, such as an AMF / SMF, or a server or host. The method may be implanted in a single control device or span more than one control device. The control device may be integrated with a node or module of the core network or RAN or be in the core network or outside thereof. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device may be another network element, such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control device and a control device provided in the radio network controller. The control device 300 may be arranged to provide control of communications in 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 may be coupled to the receiver and transmitter of the base station. The receiver and / or transmitter may be implemented as a radio front end or a remote radio head.

[0082] The following relates 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 objectives:

[0083] a) Study and specify, if agreed, an extension to DCI-based power saving adaptation during the DRX active time of the active BWP, including reduced PDCCH monitoring when C-DRX is configured [RAN1]

[0084] · Note: The power saving solutions available in Rel-15 and Rel-16 should be supported by the UE and included in the evaluation. RAN1 will request RAN2 to confirm that the power saving solutions available in Rel-15 and Rel-16 are correctly utilized.

[0085] RAN1 has adhered to the list of solutions to be considered in the previous meeting RAN1#102e. The main mechanisms are the physical downlink control channel (PDCCH) skip indication based on downlink control information (DCI) and the search space (SS) set group switching based on DCI and timers. UL transmission, such as scheduling request (SR) / configured grant (CG), was also mentioned.

[0086] Recommendation 8: The following triggering schemes may be considered for DCI-based energy saving adaptation during the DRX active time,

[0087] · Scheduling DCI

[0088] o The indication for PDCCH monitoring behavior adaptation may be

[0089] o Explicit / implicit indicated by scheduling DCI

[0090] o Joint indication for PDCCH monitoring adaptation, with

[0091] ·Cross-slot scheduling defined in Rel-16

[0092] ·Scell dormancy

[0093] ·[SS set group handover defined in Rel-16]

[0094] o The scheduling DCI used to indicate the adaptation of PDCCH monitoring behavior can be DCI format

[0095] x_1 / x_2

[0096] o DCI format x_1

[0097] o DCI format x_2

[0098] o Enhancement of retransmission handling

[0099] o Apply adaptation only after HARQ ACK condition is met

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

[0101] ·Non-scheduling DCI

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

[0103] o Explicitly indicated by DCI

[0104] o Joint indication for PDCCH monitoring adaptation, with

[0105] ·Cross-slot scheduling defined in Rel-16

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

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

[0108] o Unicast non-scheduling DCI, such as DCI formats 0_1 and 1_1 for case 2 dormancy indication

[0109] ·[Timer-based adaptation to adapt PDCCH monitoring behavior, including skip or monitoring set adaptation,

[0110] o A timer, such as a timer similar to the time search space switching timer - r16, can trigger the UE to switch between search space set groups 0 and 1]

[0111] - UL transmission, such as SR / CG

[0112] By means of 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 (e.g., via different SS periodicities) reduce or increase UE PDCCH monitoring. This can achieve power saving.

[0113] The functionality of R16 SS switching can be summarized as follows

[0114] · Introduction of NR - U's SS group (search space group) switching configuration

[0115] · One or more SS sets form GROUP0

[0116] · One or more SS sets form GROUP1

[0117] · Some search space sets may remain ungrouped and are always monitored

[0118] · Switching behavior

[0119] · GC - PDCCH 1 - bit switching group, or

[0120] · Detection of PDCCH in GROUP0 triggers a change from GROUP0 to GROUP1

[0121] · COT - side trigger changes GROUP1 -> GROUP0

[0122] · Timer - based changes GROUP1 -> GROUP0

[0123] · Multiple cells can be grouped and synchronously switched

[0124] Figure 4 An example of how to configure monitoring on two cells for the UE is shown. The gNB can configure synchronous switching for the Pcell, and if group 1 is active for the configured Pcell + Scell cell group, the Scell and the UE do not monitor on the Scell.

[0125] Through DCI-based PDCCH skipping, the network (NW) can indicate to the UE specific time periods during which the UE can skip monitoring the PDCCH. Through SS set group switching, the NW can switch between different SS set groups with different pre-configured PDCCH occasion periodicities (if an SS group is empty, this also includes zero monitoring), or the UE can autonomously change the SS set group based on a timer. How such a decision is made depends on the NW implementation, e.g., based on whether there is data available for transmission, the latency requirement for the data to be transmitted, or the scheduler algorithm.

[0126] Regarding the interaction with the current discontinuous reception (DRX) mechanism, it is generally assumed that PDCCH skipping / SS set group switching operates on top of layer 2 connected mode - DRX (C-DRX). Thus, through PDCCH skipping, the UE may not even monitor the PDCCH during the active time according to DRX, and the NW can switch to a different SS set without affecting the DRX timer.

[0127] When the network (NW) sends a PDCCH skipping command or an SS set group switching command (or switches the SS set group based on a timer), the NW cannot take into account the activity on the UE side. If uplink (UL) / downlink (DL) activity occurs after the PDCCH skipping 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 the PDCCH only after the skipping timer expires or after the delay in the SS set switching scenario (waiting for 2 time slots at the first monitoring position of the low-periodicity SS group after the transmitted PDCCH + gNB).

[0128] In traditional LTE and NR DRX, the UE moves to the active time after SR transmission, and the UE monitors the PDCCH to obtain a random access response, independent of DRX.

[0129] The interaction between PDCCH skipping and the 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) trigger, etc.

[0130] The interaction between PDCCH skipping and CG has been considered, and it has been proposed to interrupt skipping or not based on the priority of the data to be transmitted.

[0131] The interaction between SS set group switching cross-slot scheduling and DRX has been considered.

[0132] Figure 5Shows a flowchart of a method according to an exemplary embodiment.

[0133] In a first step S1, the method includes monitoring a Physical Downlink Control Channel (PDCCH) using a first monitoring mode.

[0134] In a second step S2, the method includes determining to monitor the PDCCH using a second monitoring mode based on a condition.

[0135] In a third step S3, the method includes determining the occurrence of at least one event related to a transmission from a user equipment.

[0136] In a fourth step S4, the method includes determining whether to use the first monitoring mode or the second monitoring mode to monitor the PDCCH based on the occurrence of the at least one event.

[0137] In a fifth step S5, the method includes monitoring the PDCCH using the first monitoring mode or the second monitoring mode based on the determination.

[0138] The condition may include at least one of an indication from a network node and a status of a timer.

[0139] 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, i.e., PDCCH skipping. In this case, the condition may be, for example, a DCI-based PDCCH skipping indication as described above.

[0140] Alternatively, the first monitoring mode may include monitoring a first set of search spaces groups with a first periodicity, and the second monitoring mode may include monitoring a second set of search spaces groups with a second periodicity, where the second periodicity is different from the first periodicity, i.e., the SS set group switching as described above. In this case, at least one search space set of one group has a different periodicity from at least one search space set of the other group, and the other group may be an empty set.

[0141] 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 occasion periodicities (if the SS group is empty, this also includes zero monitoring), or the UE may autonomously change the SS group based on a timer.

[0142] The method presents events (or activities) related to a transmission from a user equipment that take precedence over a PDCCH skipping command, or when a SS set group M (with a high monitoring periodicity) is active, in which case the UE stops the skipping timer and starts monitoring the PDCCH, or switches to a predefined SS set group N (N is different from M, preferably with a lower monitoring periodicity).

[0143] Even if PDCCH skipping and / or SS set group switching is triggered, the method can provide low latency for high-priority UL / DL activities.

[0144] The at least one event may include triggering a scheduling request. The event may include a scheduling request triggered by a logical channel with a priority higher than a specific threshold. Whether to use the second monitoring mode may depend on the logical channel (LCH) that triggers the SR, because different LCHs may have different thresholds for triggering the SR. That is, the event can be prioritized only when the SR is triggered by an LCH with a priority higher than a specific threshold.

[0145] 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.

[0146] The method may include 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 an event and a 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 in the Xth time slot before the PDCCH command, skipping is applied because it is an NW decision; while if the event occurs after, the skip command is not applied (i.e., the UE stops the skip timer). Similarly, in another exemplary embodiment, if the event occurs in the Xth time slot before the SS set group switching, the UE does not automatically switch to another SS set group. While if the event occurs after, the UE switches to another predefined SS set group.

[0147] 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 the cell that triggers the SR, or the cell allowed by the LCH that triggers the SR.

[0148] In an exemplary embodiment, the SS set group switching may be limited to a cell or an SS set switching cell group including the cell allowed by the LCH for triggering the SR. Similarly, stopping PDCCH skipping may also be limited to a given cell, for example, the cell allowed by the LCH that triggers the SR. The SS set group may be switched at the first DL time slot boundary X symbols after the UL time slot boundary including the PUCCH resource containing the SR, or after the last symbol of the PUCCH resource containing the SR.

[0149] The SS set group may change from group 0 to group 1, or from group N to group M, where M is the SS set group ID specifically configured by the NW

[0150] 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 start of the DRX repetition timer occurs after a skip command or when the SS set group switching group M is active.

[0151] The event may include receiving a DCP (DCI with Cyclic Redundancy Check (CRC) scrambled by a Power Saving Radio Network Temporary Identifier (PS-RNTI)). For example, when receiving a DCP (e.g., DCI format 2_6) that wakes up the associated OnDuration timer, if the DCP is received after a PDCCH skip command that starts a skip timer, the UE stops the skip timer and starts monitoring the PDCCH. This means that the UE monitors the DCP even if the PDCCH skip timer is running, to allow the NW to bring the UE back to monitoring the PDCCH when high-priority DL data becomes available for transmission.

[0152] The event may include the expiration of the 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 active time after the expiration based on the duration of a short DRX cycle.

[0153] 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.

[0154] The event may include providing a CSI report. The CSI report may include periodic, aperiodic, or semi-persistent reports. The CSI report may be sent on an uplink signaling resource such as a PUCCH / PUSCH.

[0155] The event may include indicating a Beam Failure Detection (BFD) and starting to monitor for a recovery SS (which may be indicated by a recovery search space Id). In the case of BFD, the method may include monitoring the Physical Downlink Control Channel according to the configuration of a search space set group that includes a beam failure recovery search space, or otherwise monitoring according to the monitoring mode before the event.

[0156] The event may include a Transmission Configuration Indication (TCI) from a network node. For example, when receiving a Media 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 that includes 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.

[0157] In one embodiment, the skip timer may be stopped and the monitoring of the PDCCH may start (or switch to a predefined SS set group) at the first DL slot boundary of 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 instance, the UL activity may be the transmission of any uplink signal / channel described herein (such as SR / CSI on the PUCCH or CSI on the PUSCH).

[0158] Figure 6 A flowchart of a method for PDCCH skipping according to an example embodiment is shown.

[0159] The UE is in the active time and receives an indication to skip PDCCH monitoring for X ms from the gNB. Upon receiving the indication, the UE stops monitoring the PDCCH and starts a timer for a duration of X ms.

[0160] During the time X, uplink data arrives in the buffer of the UE and the UE sends an SR. In response to sending the SR, the UE stops the timer and starts monitoring the PDCCH.

[0161] Figure 7 A flowchart of an SS group switching method according to an example embodiment is shown.

[0162] The UE is in the active time and receives an indication to switch to SS set group N from the gNB. Upon receiving the indication, the UE monitors the PDCCH infrequently according to the configuration of group N.

[0163] When the UE monitors the PDCCH according to the configuration of group N, uplink data arrives in the buffer of the UE and the UE transmits an SR. In response to sending the SR, the UE switches to SS set group M.

[0164] Figure 8 A comparison of the proposed scheme with the traditional scheme is shown. We assume Figure 4The monitoring pattern in and the SR transmitted by the UE in slot #5. In the traditional solution, the gNB may schedule UL grants only in slot #10 (based on large-periodicity SSB group 0), resulting in a delay in data scheduling. According to our proposal, the time from SR to data may be reduced (by 5 slots in this example).

[0165] Figure 9 Fig. shows the proposed mechanism for implicit cross-CC SSB group change. Here, we assume that no synchronous handover is configured between the Pcell and the Scell.

[0166] When the gNB wants to start scheduling on the Scell due to data arrival, it can trigger an A-CSI report in the PUSCH on the Pcell for the Scell and thus switch to more frequent monitoring on the Scell.

[0167] This method can be implemented in the user equipment described in Figure 2 the reference.

[0168] A device may include means for: monitoring a physical downlink control channel using a first monitoring pattern, determining to monitor the physical downlink control channel using a second monitoring pattern based on a condition, determining the occurrence of at least one event related to a transmission from a user equipment, determining whether to use the first monitoring pattern or the second monitoring pattern to monitor the physical downlink control channel based on the occurrence of the at least one event, and monitoring the physical downlink control channel using the first monitoring pattern or the second monitoring pattern based on the determination.

[0169] It should be understood that these means may include or be coupled to other units or modules, such as radio components or radio heads for transmitting and / or receiving. Although the means are described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0170] Note that although embodiments have been described with respect to LTE and 5GS, similar principles can be applied to other networks and communication systems. Thus, although certain embodiments have been described by way of example with reference to certain exemplary architectures of wireless networks, technologies, and standards above, the embodiments can be applied to any other suitable form of communication system other than the communication systems shown and described herein.

[0171] It is also noted here that although the exemplary embodiments have been described above, several variations and modifications can be made to the disclosed solutions without departing from the scope of the present invention.

[0172] Generally, various example embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects of the present 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 present invention is not limited thereto. Although the various aspects of the present invention may be illustrated and described as block diagrams, flowcharts, or using some other illustration, it should be clearly understood that, by way of non-limiting example, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0173] 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 a program product, computer software or a program includes software routines, applets, and / or macros, and may be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer-executable components, which are configured to perform the embodiments when the program runs. The one or more computer-executable components may be at least one software code or a part thereof.

[0174] In addition, in this regard, it should be noted that any block of the logic flow shown in the figure may represent a program step, or interconnected logic circuits, blocks, and functions, or a combination of program steps and logic circuits, blocks, and functions. 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. The physical media is a non-transitory medium.

[0175] 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. By way of non-limiting example, 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 dedicated 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.

[0176] Example embodiments of the present invention may be practiced in various components such as integrated circuit modules. Generally speaking, the design of an integrated circuit is a highly automated process. Sophisticated and powerful software tools may be used to convert a logic-level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0177] The foregoing description has provided a complete and informative description of exemplary embodiments of the present invention by way of non-limiting examples. However, various modifications and adaptations may become apparent to those skilled in the relevant art in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. Nevertheless, all such and similar modifications taught by the present invention will still fall within the scope of the present invention as defined in the appended claims. In fact, there are further embodiments that include combinations of one or more embodiments with any of the other embodiments previously discussed.

Claims

1. A method for communication, 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 an uplink transmission from a user equipment; based on the occurrence of the at least one event, determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel; and based on the determination, monitoring the physical downlink control channel using the first monitoring mode or the second monitoring mode, wherein in a case where synchronous handover is not configured between a primary cell and a secondary cell of the user equipment, whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel on the secondary cell is determined based on the occurrence of the at least one event on the primary cell.

2. The method 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 method according to claim 1 or claim 2, wherein, the at least one event related to the transmission includes at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgement, providing a channel state information report, and beam failure detection.

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

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

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

8. The method according to claim 7, when dependent on claim 3, further comprising: in case of beam failure detection, monitoring the physical downlink control channel according to a configuration of a set of search spaces including a beam failure recovery search space, otherwise monitoring according to the monitoring mode before the event.

9. The method according to claim 7, further comprising: determining whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the second periodicity.

10. The method according to any one of claims 1 to 9, further comprising: Determine 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 method 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. The method according to claim 11, when dependent on claim 3, wherein the at least one cell triggers the scheduling request.

13. The method 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 device for communication, 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, together with the at least one processor, cause the device to at least: monitor the physical downlink control channel using a first monitoring mode; determine to monitor the physical downlink control channel using a second monitoring mode based on a condition; determine the occurrence of at least one event related to an uplink transmission from a user equipment; based on the occurrence of the at least one event, determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel; and based on the determination, monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode, wherein in the case where no synchronous handover is configured between the primary cell and the secondary cell of the user equipment, whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel on the secondary cell is determined based on the occurrence of the at least one event on the primary cell.

15. The device according to claim 14, wherein, the condition includes at least one of an indication from a network node and a status of a timer.

16. The device according to claim 14 or claim 15, wherein, the at least one event related to the transmission includes at least one of the following: triggering of a scheduling request, transmission of a hybrid automatic repeat request negative acknowledgment, providing a channel state information report, and beam failure detection.

17. The device according to claim 16, wherein, the scheduling request is triggered by a logical channel with a priority higher than a given threshold.

18. The device according to any one of claims 14 to 17, 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.

19. The device according to claim 18, wherein, the second monitoring mode is configured for a first time period, and the at least one memory and the computer program code are further configured to, with the at least one processor, cause the device to: determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on how much time remains in the first time period.

20. The apparatus according to any one of claims 14 to 17, wherein, the first monitoring mode includes monitoring a first set of search spaces periodically with a first period, and the second monitoring mode includes monitoring a second set of search spaces periodically with a second period, wherein the second period is different from the first period.

21. The apparatus according to claim 20, when dependent on claim 16, wherein, the at least one memory and the computer program code are further configured to cause the apparatus, by using the at least one processor: in case of beam failure detection, monitor the physical downlink control channel according to the configuration of the set of search spaces including the beam failure recovery search space, otherwise monitor according to the monitoring mode before the event.

22. The apparatus according to claim 20, wherein, the at least one memory and the computer program code are further configured to cause the apparatus, by using the at least one processor: determine whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel based on the second period.

23. The apparatus according to any one of claims 14 to 22, wherein, the at least one memory and the computer program code are further configured to cause the apparatus, by using the at least one processor: determine 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.

24. The apparatus according to any one of claims 14 to 23, wherein, the monitoring mode is applied to at least one cell or a cell group including the at least one cell.

25. The apparatus according to claim 24, when dependent on claim 16, wherein the at least one cell triggers the scheduling request.

26. The apparatus according to claim 25, wherein, the at least one cell is at least one cell allowed by the logical channel that triggers the scheduling request.

27. A computer-readable medium, including program instructions for causing an apparatus to perform at least the following operations: monitor the physical downlink control channel using a first monitoring mode; determine to use a second monitoring mode to monitor the physical downlink control channel based on a condition; determine the occurrence of at least one event related to an uplink transmission from a 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 monitor the physical downlink control channel using the first monitoring mode or the second monitoring mode based on the determination, wherein in the case where no synchronous handover is configured between the primary cell and the secondary cell of the user equipment, whether to use the first monitoring mode or the second monitoring mode to monitor the physical downlink control channel on the secondary cell is determined based on the occurrence of the at least one event on the primary cell.

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