WO2024065179A1

WO2024065179A1 - Methods, devices, and medium for communication

Info

Publication number: WO2024065179A1
Application number: PCT/CN2022/121740
Authority: WO
Inventors: Gang Wang; Lei Chen
Original assignee: Nec Corporation
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2024-04-04

Abstract

Example embodiments of the present disclosure relate to methods, devices, and computer storage medium for communication. A terminal device performs a PDCCH monitoring according to a first PDCCH monitoring pattern; and switches to a second PDCCH monitoring pattern based on at least one of a plurality of conditions related to a timer in an active time of a DRX cycle, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern. As such, since the first PDCCH monitoring pattern is sparser than the second PDCCH monitoring pattern, the PDCCH monitoring overhead can be reduced, and thus the power consumption at the terminal device can be saved.

Description

METHODS, DEVICES, AND MEDIUM FOR COMMUNICATION

FIELD

Example embodiments of the present disclosure generally relate to the field of communication techniques and in particular, to methods, devices, and a computer readable medium for communication.

BACKGROUND

It is proposed to study extended reality (XR) enhancement in release 18. XR-specific power saving techniques are proposed to be studied to reduce the overall user equipment (UE) power consumption.

The varying frame encoding delay and network transfer time may introduce jitter in packet arrival time at a network device, such as gNB. Downlink (DL) burst may arrive later than the expected time of arrival, where discontinuous reception (DRX) on duration start offset is configured, the UE should wait for DL burst arrival while performing physical downlink control channel (PDCCH) monitoring, which increases UE power consumption. Therefore, it is beneficial for UE to further reduce the power consumption.

SUMMARY

In general, example embodiments of the present disclosure provide methods, devices and a computer storage medium for communication.

In a first aspect, there is provided a method of communication. The method comprises: performing, at a terminal device, a physical downlink control channel (PDCCH) monitoring according to a first PDCCH monitoring pattern; and switching to a second PDCCH monitoring pattern based on at least one of a plurality of conditions: a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group, a ra-ContentionResolutionTimer is running, msgB-ResponseWindow is running, scheduling request is sent on a physical uplink control channel (PUCCH) and is pending, or a PDCCH indicating a new transmission addressed to a cell-radio network temporary identity (C-RNTI) of a media access control (MAC) entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern.

In a second aspect, there is provided a method of communication. The method comprises: determining, at a terminal device, a duration within a periodicity for a physical downlink control channel (PDCCH) monitoring; and performing the PDCCH monitoring according to a first PDCCH monitoring pattern within the duration; and in accordance with a determination that a PDCCH is detected in a slot of the duration, switching to a second PDCCH monitoring pattern to perform the PDCCH monitoring within the duration, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern.

In a third aspect, there is provided a method of communication. The method comprises: determining, at a network device, a first PDCCH monitoring pattern and a second PDCCH monitoring pattern for a physical downlink control channel (PDCCH) monitoring, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern; and transmitting, to a terminal device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In a fourth aspect, there is provided a terminal device. The terminal device comprises a processor and a memory. The memory is coupled to the processor and stores instructions thereon. The instructions, when executed by the processor, cause the terminal device to perform the method according to the first or the second aspect above.

In a fifth aspect, there is provided a network device. The network device comprises a processor and a memory. The memory is coupled to the processor and stores instructions thereon. The instructions, when executed by the processor, cause the network device to perform the method according to the third aspect above.

In a sixth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to the first aspect or the second aspect or the third aspect above.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates a schematic diagram of a DRX cycle;

FIG. 2 illustrates a schematic diagram of a search space;

FIGS. 3A-3B illustrate schematic diagrams of DL data due to jitter;

FIG. 4 illustrates an example communication system in which some embodiments of the present disclosure can be implemented;

FIG. 5 illustrates a signalling chart illustrating communication process in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates a schematic diagram for switching PDCCH monitoring patterns in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates a schematic diagram of an example pattern indication filed in low power wake up signal in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates a signalling chart illustrating communication process in accordance with some embodiments of the present disclosure;

FIG. 9 illustrates a schematic diagram for switching PDCCH monitoring patterns within a duration in accordance with some embodiments of the present disclosure;

FIG. 10 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure;

FIG. 11 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure;

FIG. 12 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure; and

FIG. 13 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

In some examples, values, procedures, or apparatus are referred to as “best, ” “lowest, ” “highest, ” “minimum, ” “maximum, ” or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR) , Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) , 5.5G, 5G-Advanced networks, or the sixth generation (6G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “terminal device” refers to any device having wireless or wired communication capabilities. Examples of terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also be incorporated one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

As used herein, the term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a satellite, a unmanned aerial systems (UAS) platform, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

In one embodiment, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device and the second network device. In one embodiment, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

Communications discussed herein may conform to any suitable standards including, but not limited to, New Radio Access (NR) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , cdma2000, and Global System for Mobile Communications (GSM) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.85G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) , and the sixth (6G) communication protocols. The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

The terminal device or the network device may have Artificial intelligence (AI) or machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal device or the network device may work on several frequency ranges, e.g. FR1 (410 MHz –7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network device under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, or channel emulator.

The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” The terms “first, ” “second, ” and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some cases, the UE may use discontinuous reception (DRX) in order to reduce power consumption. When DRX is configured, the UE does not have to continuously monitor PDCCH. FIG. 1 illustrates a schematic diagram of a DRX cycle. DRX is characterized by the following:

- on-duration: duration that the UE waits for, after waking up, to receive PDCCHs. If the UE successfully decodes a PDCCH, the UE stays awake and starts the inactivity timer;

- inactivity-timer: duration that the UE waits to successfully decode a PDCCH, from the last successful decoding of a PDCCH, failing which it can go back to sleep. The UE shall restart the inactivity timer following a single successful decoding of a PDCCH for a first transmission only (i.e., not for retransmissions) ;

- retransmission-timer: duration until a retransmission can be expected;

- cycle: specifies the periodic repetition of the on-duration followed by a possible period of inactivity (see FIG. 1) ;

- active-time: total duration that the UE monitors PDCCH. This includes the "on-duration" of the DRX cycle, the time UE is performing continuous reception while the inactivity timer has not expired, and the time when the UE is performing continuous reception while waiting for a retransmission opportunity.

The “active time” for Serving Cells in a DRX group includes the time while:

-drx-onDurationTimer or drx-InactivityTimer configured for the DRX group is running; or

- drx-RetransmissionTimerDL, drx-RetransmissionTimerUL or drx-RetransmissionTimerSL is running on any Serving Cell in the DRX group; or

- ra-ContentionResolutionTimer or msgB-ResponseWindow is running; or

- a Scheduling Request is sent on PUCCH and is pending. If this Serving Cell is part of a non-terrestrial network, the Active Time is started after the Scheduling Request transmission that is performed when the SR_COUNTER is 0 for all the SR configurations with pending SR (s) plus the UE-gNB RTT; or

- a PDCCH indicating a new transmission addressed to the cell-radio network temporary identity (C-RNTI) of the media access control (MAC) entity has not been received after successful reception of a Random Access Response for the Random Access Preamble not selected by the MAC entity among the contention-based Random Access Preamble.

There are multiple DRX timers related to active time, include:

- drx-onDurationTimer: the duration at the beginning of a DRX cycle;

- drx-SlotOffset: the delay before starting the drx-onDurationTimer;

- drx-InactivityTimer: the duration after the PDCCH occasion in which a PDCCH indicates a new UL or DL transmission for the MAC entity;

- drx-RetransmissionTimerDL (per DL hybrid automatic repeat request (HARQ) process except for the broadcast process) : the maximum duration until a DL retransmission is received;

- drx-RetransmissionTimerUL (per UL HARQ process) : the maximum duration until a grant for UL retransmission is received.

The timer “drx-onDurationTimer” may be started:

1> if the Short DRX cycle is used for a DRX group, and [ (SFN × 10) + subframe number] modulo (drx-ShortCycle) = (drx-StartOffset) modulo (drx-ShortCycle) :

2> start drx-onDurationTimer for this DRX group after drx-SlotOffset from the beginning of the subframe.

1> if the Long DRX cycle is used for a DRX group, and [ (SFN × 10) + subframe number] modulo (drx-LongCycle) = drx-StartOffset:

2> if DCP monitoring is configured for the active DL BWP as specified in TS 38.213, clause 10.3:

3> if DCP indication associated with the current DRX cycle received from lower layer indicated to start drx-onDurationTimer, as specified in TS 38.213; or

3> if all DCP occasion (s) in time domain, as specified in TS 38.213, associated with the current DRX cycle occurred in Active Time considering grants/assignments/DRX Command MAC CE/Long DRX Command MAC CE received and Scheduling Request sent until 4 ms prior to start of the last DCP occasion, or during a measurement gap, or when the MAC entity monitors for a PDCCH transmission on the search space indicated by recoverySearchSpaceId of the SpCell identified by the C-RNTI while the ra-ResponseWindow is running (as specified in clause 5.1.4) ; or

3> if ps-Wakeup is configured with value true and DCP indication associated with the current DRX cycle has not been received from lower layers:

4> start drx-onDurationTimer after drx-SlotOffset from the beginning of the subframe.

2> else:

3> start drx-onDurationTimer for this DRX group after drx-SlotOffset from the beginning of the subframe.

As shown in FIG. 1, a UE shall monitor PDCCH within an On Duration. PDCCH monitoring may be based on a search space. For each DL bandwidth part (BWP) configured to a UE in a serving cell, the UE is provided by higher layers with S≤10 search space sets where, for each search space set from the S search space sets, the UE is provided the following by SearchSpace:

- a search space set index s, 0<s<40, by searchSpaceId,

- an association between the search space set s and a CORESET p by controlResourceSetId or by controlResourceSetId-v1610,

- a PDCCH monitoring periodicity of k_s slots and a PDCCH monitoring offset of o_s slots, by monitoringSlotPeriodicityAndOffset or by monitoringSlotPeriodicityAndOffset-r17,

- a PDCCH monitoring pattern within a slot, indicating first symbol (s) of the CORESET for PDCCH monitoring within each slot where the UE monitors PDCCH, by monitoringSymbolsWithinSlot,

- a duration of T_s<k_s indicating a number of slots that the search space set s exists by duration, or a number of slots in consecutive groups of slots where the search space set s can exist by duration-r17,

- a bitmap, by monitoringSlotsWithinSlotGroup, that applies per group of slots and provides a PDCCH monitoring pattern indicating slots in a group of slots for PDCCH monitoring,

- a size of the group of slots is same as a size of monitoringSlotsWithinSlotGroup,

- for a Type1-PDCCH CSS set provided by ra-SearchSpace in dedicated RRC signaling, or for a Type3-PDCCH CSS set, or for a USS set, the PDCCH monitoring pattern indicates only consecutive slots in the group of slots for PDCCH monitoring and, at least for one combination (X _s, Y _s) indicated by the UE as a capability, a number of the consecutive slots is not larger than Y _s.

FIG. 2 illustrates a schematic diagram of a search space. As shown in FIG. 2, the PDCCH monitoring periodicity is k _s=8, the offset is O _s=1, the duration is T _s=3, and the monitoring symbols within a slot may be 10000001000000. An information element “Search space” may defined as Table 1:

Table 1

A UE may determine a PDCCH monitoring occasion on an active DL BWP from the PDCCH monitoring periodicity, the PDCCH monitoring offset and the PDCCH monitoring pattern within a slot. For search space set s, the UE determines that PDCCH monitoring occasions exist in a slot with number

in a frame with number n _f if

If monitoringSlotsWithinSlotGroup is provided, the slot is the first slot in a group of slots and PDCCH monitoring occasions exist in the group of slots. The UE monitors PDCCH candidates for search space set s for T _s consecutive slots, starting from

and does not monitor PDCCH candidates for search space set s for the next k _s-T _s consecutive slots.

As described above, DL burst may arrive later than an expected time of arrival due to jitter. FIGS. 3A-3B illustrate schematic diagrams of DL data due to jitter. As shown in FIG. 3A, the DL data arrives later than the start time of OnDurationTimer, but still arrives while OnDurationTimer is running. As shown in FIG. 3B, the DL data arrives later than the start time of OnDurationTimer, and misses the on duration.

While the UE is waiting for the DL data, it is performing PDCCH monitoring during the period 310 in FIG. 3A or the period 320 in FIG. 3B, which may cause a power consumption at UE.

Embodiments of the present disclosure provide a solution of communication. In the solution, a terminal device may perform PDCCH monitoring in a first PDCCH monitoring pattern and switch to a second PDCCH monitoring pattern if one or more of some conditions are met. Since the first PDCCH monitoring pattern is sparser than the second PDCCH monitoring pattern, the PDCCH monitoring overhead can be reduced, and thus the power consumption at the terminal device can be saved. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

FIG. 4 illustrates an example communication system 400 in which some embodiments of the present disclosure can be implemented. The communication network 400 includes a network device 410 and a terminal device 420. The network device 410 can provide services to the terminal device 420.

In the system 100, it is assumed that the terminal device 420 is located within coverage of the network device 410. In some examples, a link from the network device 410 to the terminal device 420 is referred to as a downlink (DL) , while a link from the terminal device 420 to the network device 410 is referred to as an uplink (UL) . In downlink, the network device 410 is a transmitting (TX) device (or a transmitter) and the terminal device 420 is a receiving (RX) device (or a receiver) . In uplink, the terminal device 420 is a transmitting TX device (or a transmitter) and the network device 410 is a RX device (or a receiver) . In some embodiments, the network device 410 and the terminal device 420 may communicate with direct links/channels. DL may comprise one or more logical channels, including but not limited to a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH) . UL may comprise one or more logical channels, including but not limited to a Physical Uplink Control Channel (PUCCH) and a Physical Uplink Shared Channel (PUSCH) . As used herein, the term “channel” may refer to a carrier or a part of a carrier consisting of a contiguous set of resource blocks (RBs) on which a channel access procedure is performed in shared spectrum.

In some embodiments, the terminal device 420 may be in a main mode. In the context of the present disclose, the terms “main radio” , “main receiver” can be used interchangeably. The terminal device 420 may receive/transmit normal DL/UL transmission (e.g., PDSCH, PDCCH, PUSCH, PUCCH, etc. ) in the main mode with the main radio. In some embodiments, the terminal device 420 may be in an idle/inactive mode. For example, the same coverage as the normal DL/UL transmission cannot be provided and the terminal device 420 may receive a wake up signal (WUS) with wake up receivers (WUR) .

Communications in the system 100, between the network device 410 and the terminal device 420 for example, may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Divided Multiple Address (CDMA) , Frequency Divided Multiple Address (FDMA) , Time Divided Multiple Address (TDMA) , Frequency Divided Duplexer (FDD) , Time Divided Duplexer (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Divided Multiple Access (OFDMA) and/or any other technologies currently known or to be developed in the future.

Embodiments of the present disclosure can be applied to any suitable scenarios. For example, embodiments of the present disclosure can be implemented at reduced capability NR devices. Alternatively, embodiments of the present disclosure can be implemented in one of the followings: NR multiple-input and multiple-output (MIMO) , NR sidelink enhancements, NR systems with frequency above 52.6GHz, an extending NR operation up to 71GHz, narrow band-Internet of Thing (NB-IOT) /enhanced Machine Type Communication (eMTC) over non-terrestrial networks (NTN) , NTN, UE power saving enhancements, NR coverage enhancement, NB-IoT and LTE-MTC, Integrated Access and Backhaul (IAB) , NR Multicast and Broadcast Services, or enhancements on Multi-Radio Dual-Connectivity.

It is to be understood that the numbers of devices (i.e., the network device 410 and the terminal device 420) and their connection relationships and types shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The system 100 may include any suitable numbers of devices adapted for implementing embodiments of the present disclosure.

Reference is further made to FIG. 5, which illustrates a signalling chart illustrating communication process 500 in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the process 500 will be described with reference to FIG. 4. The process 500 may involve the network device 410 and the terminal device 420.

The network device 410 determines 510 a first PDCCH monitoring pattern and a second PDCCH monitoring pattern, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern, in other words, the first PDCCH monitoring pattern is sparser than the second PDCCH monitoring pattern.

The network device 410 may transmits 520 configuration information 522 to the terminal device 420. The configuration information 522 may indicate a first PDCCH monitoring pattern and/or a second PDCCH monitoring pattern, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern.

In some example embodiments, the first PDCCH monitoring pattern may refer to a sparse PDCCH monitoring pattern (or a sparse pattern) , and the second PDCCH monitoring pattern may refer to a dense PDCCH monitoring pattern (or a dense pattern) .

In some example embodiments, the configuration information 522 may be transmitted through an RRC message or RRC signalling.

In some example embodiments, the first PDCCH monitoring pattern is configured for on duration, for example, configured for drx-onDurationTimer of DRX operation. In some example embodiments, the second PDCCH monitoring pattern may be configured for other active time, which will be described in detail below. In some example embodiments, the second PDCCH monitoring pattern may be a continuous PDCCH monitoring pattern.

In some example embodiments, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern have different time domain parameters, the parameters may include a periodicity, a slot offset, a duration, or monitoring symbols within a slot. An example of the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may refer to FIG. 6 shown below.

In some example embodiments, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may correspond to a same search space. For example, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may be defined for a search space. For example, the network device 410 may configure two different patterns for a search space. For example, the configuration information 522 may be carried in an information element “SearchSpace” in the RRC signalling.

In some other example embodiments, the first PDCCH monitoring pattern may correspond to a first search space, and the second PDCCH monitoring pattern may correspond to a second search space. In other words, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may belong to two different search spaces.

In some other example embodiments, the first PDCCH monitoring pattern may correspond to a first search space group (SSG) , and the second PDCCH monitoring pattern may correspond to a second search space group. In other words, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may belong to two different search space groups.

Alternatively, the configuration information 522 may indicate a list of PDCCH monitoring patterns. The list of PDCCH monitoring patterns may include multiple PDCCH monitoring patterns. For example, a first pattern in the list may indicate PDCCH monitoring every slot, a second pattern in the list may indicate PDCCH monitoring every 2 slots, a third pattern in the list may indicate PDCCH monitoring every 4 slots, etc. It is to be appreciated that the examples are only for the purpose of illustration without suggesting any limitation as to the scope of the disclosure.

In addition or alternatively, the network device 410 may transmit a first indication of the first PDCCH monitoring pattern to the terminal device 420. For example, the first indication may be an index or an identifier of the first PDCCH monitoring pattern in the list. In some examples, the network device 410 may indicate one pattern from the list as the first PDCCH monitoring pattern by the first indication.

In some examples, the first indication may be transmitted via one or more of: an RRC message, downlink control information (DCI) , a wake up signal (WUS) , or a MAC control element (CE) . For example, the first indication may be carried in a new filed of DCI, a new filed of wake up signal, or a new MAC CE.

In addition or alternatively, the network device 410 may transmit a second indication of the second PDCCH monitoring pattern to the terminal device 420. For example, the second indication may be an index or an identifier of the second PDCCH monitoring pattern in the list. In some examples, the network device 410 may indicate another one pattern from the list as the second PDCCH monitoring pattern by the second indication.

In some examples, the second indication may be transmitted via one or more of: an RRC message, downlink control information (DCI) , a wake up signal, or a MAC control element (CE) . For example, the second indication may be carried in a new filed of DCI, a new filed of wake up signal, or a new MAC CE.

It is understood that the first indication and the second indication may be transmitted separately or may be transmitted together. For example, the first indication and the second indication may be carried in a same field of DCI, or in a same filed of wake up signal, or in a same MAC CE. The present disclosure does not limit this aspect.

Alternatively, the configuration information 522 may indicate multiple patterns (dense PDCCH monitoring patterns) associated with multiple conditions, which will be described below in detail.

On the other side of communication, the terminal device 420 may receive 524 the configuration information 522. In some example embodiments, the configuration information 522 may indicate the first PDCCH monitoring pattern, and the terminal device 420 may be aware of the first PDCCH monitoring pattern based on the configuration information 522. In some example embodiments, the configuration information 522 may indicate the second PDCCH monitoring pattern, and the terminal device 420 may be aware of the second PDCCH monitoring pattern based on the configuration information 522. In some example embodiments, the configuration information 522 may not indicate the second PDCCH monitoring pattern, in this case, the terminal device 420 may determine that the second PDCCH monitoring pattern is a continuous PDCCH monitoring pattern.

In some example embodiments, the configuration information 522 may indicate a list of PDCCH monitoring patterns. In addition or alternatively, the terminal device 420 may receive a first indication of the first PDCCH monitoring pattern. In addition or alternatively, the terminal device 420 may receive a second indication of the second PDCCH monitoring pattern.

The terminal device 420 performs 530 a PDCCH monitoring according to the first PDCCH monitoring pattern. In some examples, the terminal device 420 may perform the PDCCH monitoring according to the first PDCCH monitoring pattern by default within “on Duration” of a DRX cycle.

The terminal device 420 switches 540 to the second PDCCH monitoring pattern if one or more of the multiple conditions are met:

(1) a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running,

(2) a drx-RetransmissionTimerDL is running on a serving cell in the DRX group,

(3) a drx-RetransmissionTimerUL is running on the serving cell in the DRX group,

(4) a drx-RetransmissionTimerSL is running on the serving cell in the DRX group,

(5) a ra-ContentionResolutionTimer is running,

(6) a msgB-ResponseWindow is running,

(7) a scheduling request is sent on a physical uplink control channel (PUCCH) and is pending, or

(8) a PDCCH indicating a new transmission addressed to a C-RNTI of a MAC entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble.

In some example embodiments, if one of the conditions for denser monitoring pattern in met, the terminal device 420 may switch to perform the PDCCH monitoring according to the second PDCCH monitoring pattern.

In some example embodiments, multiple patterns (such as M PDCCH monitoring patterns) associated with the multiple conditions are configured, the terminal device 420 may determine which condition is met (such as condition 1) , and further select a PDCCH monitoring pattern from the M PDCCH monitoring patterns based on the condition 1. Specifically, the terminal device 410 may select the pattern, which is associated with the condition 1, as the second PDCCH monitoring pattern. And then the terminal device 420 may switch to the second PDCCH monitoring pattern which is associated with the condition 1.

In some examples, there may be one or more conditions associated with a same PDCCH monitoring pattern in the M PDCCH monitoring patterns. In some examples, different conditions may be associated with different PDCCH monitoring patterns in the M PDCCH monitoring patterns. The present disclosure does not limit this aspect.

For example, the conditions (2) - (4) may be a drx-RetransmissionTimerDL, a drx-RetransmissionTimerUL, or a drx-RetransmissionTimerSL is running on any serving cell in the DRX group, and they may associate with a same PDCCH monitoring pattern.

For example, the conditions (5) - (6) may be ra-ContentionResolutionTimer or msgB-ResponseWindow is running, and they may associate with a same PDCCH monitoring pattern.

For example, the condition (7) may be “a Scheduling Request (SR) is sent on PUCCH and is pending. If this Serving Cell is part of a non-terrestrial network, the Active Time is started after the Scheduling Request transmission that is performed when the SR_COUNTER is 0 for all the SR configurations with pending SR (s) plus the UE-gNB round trip time (RTT) ” , and it may be associate with a PDCCH monitoring pattern different from that associated with condition (1) .

It is to be appreciated that the examples are only for the purpose of illustration without suggesting any limitation as to the scope of the disclosure.

In some example embodiments, if drx-InactivityTimer is started, the terminal device 420 may switch to the second PDCCH monitoring pattern. For example, if drx-onDurationTimer is started while drx-InactivityTimer is still running, the terminal device 420 may perform the PDCCH monitoring according to the second PDCCH monitoring pattern.

In some examples, if none of the multiple conditions is met and the drx-onDurationTimer is running, the terminal device 420 may switch back to the first PDCCH monitoring pattern. In other words, when drx-InactivityTimer expires, if drx-onDurationTimer is running and none of the multiple conditions for the second PDCCH monitoring pattern is met, the terminal device 420 may switch from the second PDCCH monitoring pattern to the first PDCCH monitoring pattern.

In some other examples, once the drx-InactivityTimer is started, the terminal device 420 may keep performing the PDCCH monitoring according to the second PDCCH monitoring pattern until a next DRX cycle. In other words, the second PDCCH monitoring pattern is used until the next DRX cycle since the drx-InactivityTimer is started, regardless whether the drx-InactivityTimer is running or expires.

As such, a first PDCCH monitoring pattern is configured for on-duration of a DRX cycle, and the terminal device 420 may monitor the PDCCH according to the first PDCCH monitoring pattern by default. Once an inactivity timer (or another active timer of a DRX cycle) is running, the terminal device 420 shall monitor the PDCCH according to a second PDCCH monitoring pattern, which is denser than the first PDCCH monitoring pattern. Since the first PDCCH monitoring pattern is sparser, the unnecessary PDCCH monitoring overhead may be reduced and the power consumption at the terminal device 420 may be saved. Additionally, in some examples, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may correspond to a search space, the switching between the first and the second PDCCH monitoring patterns may be flexible, and the latency may be avoided comprising with an SSSG switching. Therefore, a good balance between the latency and the power consumption can be reached.

FIG. 6 illustrates a schematic diagram for switching PDCCH monitoring patterns 600 in accordance with some embodiments of the present disclosure. As shown in FIG. 6, the terminal device 420 may perform the PDCCH monitoring according to the first PDCCH monitoring pattern by default, and perform the PDCCH monitoring according to the second PDCCH monitoring pattern if a drx-InactivityTimer is started. The first PDCCH monitoring pattern is a comb-like pattern for onDuration, and the first PDCCH monitoring pattern is sparser than the second PDCCH monitoring pattern which is a continuous PDCCH monitoring pattern in FIG. 6. As shown in FIG. 6, the switching of the PDCCH monitoring pattern is based on a new transmission indication at 610, that is, a PDCCH that indicates a new transmission is successfully received.

As described above, the terminal device 420 may switch to the second PDCCH monitoring pattern if one or more of the multiple conditions (1) - (8) are met. In some example embodiments, the switching may be performed automatically based on an RRC configuration from the network device 410, or may be performed dynamically based on a DCI/WUS/MAC CE from the network device 410. FIG. 7 illustrates a schematic diagram of an example pattern indication filed in low power wake up signal 700 in accordance with some embodiments of the present disclosure. As shown in FIG. 7, the network device 410 may transmit different WUSs to different UEs. Specifically, the WUS to UE #1 or UE #N may include a wake-up indication and an SCell dormancy indication. As for UE #2, the WUS may include a wake-up indication 721, an SCell dormancy indication 722, and a pattern indication 723. For example, the pattern indication 723 may be a new field of the WUS.

Based on the example embodiments described in accordance with FIGS. 5-7, a first sparse PDCCH monitoring pattern may be used for PDCCH monitoring, thus the power consumption at the terminal device may be reduced. In addition, the conditions are timer related, thus the switching may be performed automatically without additional switching indication (such as DCI) , and the switching delay may be reduced.

Reference is further made to FIG. 8, which illustrates a signalling chart illustrating communication process 800 in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the process 800 will be described with reference to FIG. 4. The process 800 may involve the network device 410 and the terminal device 420.

The network device 410 determines 810 a first PDCCH monitoring pattern (or a first PDCCH monitoring slot pattern) and a second PDCCH monitoring pattern (or a second PDCCH monitoring slot pattern) within a duration of a search space, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern, in other words, the first PDCCH monitoring pattern is sparser than the second PDCCH monitoring pattern.

The network device 410 may transmits 820 configuration information 822 to the terminal device 420. The configuration information 822 may indicate a first PDCCH monitoring pattern and/or a second PDCCH monitoring pattern within a same duration, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern. In some example embodiments, the configuration information 822 may be transmitted through an RRC message or RRC signalling.

In some example embodiments, the first PDCCH monitoring pattern may refer to a sparse PDCCH monitoring pattern (or a sparse slot pattern) , and the second PDCCH monitoring pattern may refer to a dense PDCCH monitoring pattern (or a dense slot pattern) . In some examples, the second PDCCH monitoring pattern may be a continuous PDCCH monitoring slot pattern. In some examples, the second PDCCH monitoring pattern may indicate to perform the PDCCH monitoring every slot within a duration of a search space.

In some example embodiments, the first PDCCH monitoring pattern may be used by the terminal device 420 by default. In dome example embodiments, the second PDCCH monitoring pattern may be used by the terminal device 420 when a PDCCH is detected.

In some example embodiments, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern may correspond to a same search space. For example, the irst PDCCH monitoring pattern and the second PDCCH monitoring pattern are configured for slots specified by duration (T _s) in a search space.

Alternatively, the configuration information 822 may indicate a list of PDCCH monitoring patterns. The list of PDCCH monitoring patterns may include multiple PDCCH monitoring patterns (or be called as multiple PDCCH monitoring slot patterns) . For example, a first pattern in the list may indicate PDCCH monitoring every slot, a second pattern in the list may indicate PDCCH monitoring every 2 slots, a third pattern in the list may indicate PDCCH monitoring every 4 slots, etc. It is to be appreciated that the examples are only for the purpose of illustration without suggesting any limitation as to the scope of the disclosure.

In some examples, the first indication may be transmitted via one or more of: an RRC message, a DCI, a WUS, or a MAC CE. For example, the first indication may be carried in a new filed of DCI, a new filed of wake up signal, or a new MAC CE.

In some examples, the second indication may be transmitted via one or more of: an RRC message, a DCI, a WUS, or a MAC CE. For example, the second indication may be carried in a new filed of DCI, a new filed of wake up signal, or a new MAC CE.

On the other side of communication, the terminal device 420 may receive 824 the configuration information 822. In some example embodiments, the configuration information 822 may indicate the first PDCCH monitoring pattern, and the terminal device 420 may be aware of the first PDCCH monitoring pattern based on the configuration information 822. In some example embodiments, the configuration information 822 may indicate the second PDCCH monitoring pattern, and the terminal device 420 may be aware of the second PDCCH monitoring pattern based on the configuration information 822. In some example embodiments, the configuration information 822 may not indicate the second PDCCH monitoring pattern, in this case, the terminal device 420 may determine that the second PDCCH monitoring pattern is a continuous PDCCH monitoring pattern.

In some example embodiments, the configuration information 822 may indicate a list of PDCCH monitoring patterns. In addition or alternatively, the terminal device 420 may receive a first indication of the first PDCCH monitoring pattern. In addition or alternatively, the terminal device 420 may receive a second indication of the second PDCCH monitoring pattern.

The terminal device 420 determines 830 a duration within a periodicity for a PDCCH monitoring. The terminal device 420 performs 840 a PDCCH monitoring according to the first PDCCH monitoring pattern. In some examples, the terminal device 420 may perform the PDCCH monitoring according to the first PDCCH monitoring pattern by default within a duration in a search space.

The terminal device 420 switches 850 to the second PDCCH monitoring pattern if a PDCCH is received. In some examples, if a PDCCH is detected (such as a DCI is received) in a slot of the duration, the terminal device 420 may switch to the second PDCCH monitoring pattern within the duration, that is, the terminal device 420 may perform the PDCCH monitoring according to the second PDCCH monitoring pattern after receiving the PDCCH.

In some example embodiments, the switching may be performed automatically or autonomously based on an RRC configuration from the network device 410, or may be performed dynamically based on a DCI/WUS/MAC CE from the network device 410.

In some examples, the second PDCCH monitoring pattern is a continuous PDCCH monitoring slot pattern. In some examples, once a PDCCH is received, the terminal device 420 may start monitoring the PDCCH consecutively in the slots specified by duration.

FIG. 9 illustrates a schematic diagram for switching PDCCH monitoring patterns 900 within a duration in accordance with some embodiments of the present disclosure. As shown in FIG. 9, it is assumed that the monitoring slot periodicity is 20 slots, the offset is 0, and the duration is 10 slots, as shown in Table 2.

Table 2

The terminal device 410 performs a PDCCH monitoring according to a first PDCCH monitoring slot pattern by default, and switches to a second PDCCH monitoring slot pattern after receiving a PDCCH at 910.

The first PDCCH monitoring slot pattern is a sparse slot pattern, such as a comb-like pattern in FIG. 9, the terminal device 420 may perform the PDCCH monitoring in slot #0, #2 and #4, without in slot #1 and slot #3. The second PDCCH monitoring slot pattern is a dense slot pattern or a continuous slot pattern in FIG. 9, the terminal device 420 may perform the PDCCH monitoring in every slot.

As such, a first PDCCH monitoring slot pattern is configured for the duration of a search space, and the terminal device 420 may monitor the PDCCH according to the first PDCCH monitoring slot pattern by default. Once a PDCCH is received, the terminal device 420 shall monitor the PDCCH according to a second PDCCH monitoring slot pattern, which is denser than the first PDCCH monitoring slot pattern. Since the first PDCCH monitoring slot pattern is sparser, the unnecessary PDCCH monitoring overhead may be reduced and the power consumption at the terminal device 420 may be saved. Additionally, since the first PDCCH monitoring slot pattern and the second PDCCH monitoring slot pattern correspond to the duration of a search space, the switching between the first and the second PDCCH monitoring slot patterns may be flexible, and the latency may be avoided comprising with an SSSG switching. Therefore, a good balance between the latency and the power consumption can be reached.

FIG. 10 illustrates a flowchart of an example method 1000 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the terminal device 420 with reference to FIG. 4.

At block 1010, the terminal device 420 performs a PDCCH monitoring according to a first PDCCH monitoring pattern. At block 1020, the terminal device 420 switches to a second PDCCH monitoring pattern based on at least one of a plurality of conditions: a drx-InactivityTimer configured for a DRX group is running, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group, a ra-ContentionResolutionTimer is running, a msgB-ResponseWindow is running, a scheduling request is sent on a PUCCH and is pending, or a PDCCH indicating a new transmission addressed to a C-RNTI of a MAC entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern.

In some example embodiments, the first PDCCH monitoring pattern corresponds to a first search space or a first search space group, and the second PDCCH monitoring pattern corresponds to a second search space or a second search space group.

In some example embodiments, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern are two different patterns of a same search space.

In some example embodiments, if none of the plurality of conditions is met and a drx-onDurationTimer is running, the terminal device 420 switches back to the first PDCCH monitoring pattern.

In some example embodiments, once the drx-InactivityTimer is started, the terminal device 420 keeps performing the PDCCH monitoring according to the second PDCCH monitoring pattern until a next DRX cycle.

In some example embodiments, the terminal device 420 receives, from a network device 410, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the terminal device 420 receives, from a network device 410, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, the first indication is transmitted via at least one of: a radio resource control (RRC) message, downlink control information (DCI) , a wake up signal, or a medium access control (MAC) control element (CE) .

In some example embodiments, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the terminal device 420 receives, from the network device 410, a second indication of the second PDCCH monitoring pattern.

In some example embodiments, the second indication is transmitted via at least one of: an RRC message, a DCI, a wake up signal, or a MAC CE.

In some example embodiments, the configuration information is transmitted via an RRC message.

In some example embodiments, the second PDCCH monitoring pattern is one of a plurality of patterns associated with the plurality of conditions.

In some example embodiments, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern have different time domain parameters comprising at least one of: a periodicity, a slot offset, a duration, or monitoring symbols within a slot.

In some example embodiments, the first PDCCH monitoring pattern is configured for a drx-onDurationTimer of a DRX operation.

In some example embodiments, the second PDCCH monitoring pattern comprises a continuous monitoring pattern.

FIG. 11 illustrates a flowchart of an example method 1100 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of the terminal device 420 with reference to FIG. 4.

At block 1110, the terminal device 420 determines a duration within a periodicity for a PDCCH monitoring. At block 1120, the terminal device 420 performs the PDCCH monitoring according to a first PDCCH monitoring pattern within the duration. At block 1130, if a PDCCH is detected in a slot of the duration, the terminal device 420 switches to a second PDCCH monitoring pattern to perform the PDCCH monitoring within the duration, the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the terminal device 420 receives, from the network device 410, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, the first indication is transmitted via at least one of: an RRC message, a DCI, a wake up signal, or a MAC CE.

FIG. 12 illustrates a flowchart of an example method 1200 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1200 will be described from the perspective of the network device 410 with reference to FIG. 4.

At block 1210, the network device 410 determines a first PDCCH monitoring pattern and a second PDCCH monitoring pattern for a PDCCH monitoring, the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern. At block 1220, the network device 420 transmits, to a terminal device 420, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the network device 410 transmits, to the terminal device 420, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the network device 410 transmits, to the terminal device 420, a second indication of the second PDCCH monitoring pattern.

In some example embodiments, the second PDCCH monitoring pattern is one of a plurality of patterns associated with a plurality of conditions comprising: a drx-InactivityTimer configured for a DRX group is running at the terminal device, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group at the terminal device, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group at the terminal device, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group at the terminal device, a ra-ContentionResolutionTimer is running at the terminal device, a msgB-ResponseWindow is running at the terminal device, a scheduling request is sent on a PUCCH by the terminal device and is pending, and a PDCCH indicating a new transmission addressed to a C-RNTI of a MAC entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble.

Details of some embodiments according to the present disclosure have been described with reference to FIGS. 4-12. Now an example implementation of the terminal device and the network device will be discussed below.

In some example embodiments, a terminal device comprises circuitry configured to:performs a PDCCH monitoring according to a first PDCCH monitoring pattern; and switch to a second PDCCH monitoring pattern based on at least one of a plurality of conditions: a drx-InactivityTimer configured for a DRX group is running, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group, a ra-ContentionResolutionTimer is running, a msgB-ResponseWindow is running, a scheduling request is sent on a PUCCH and is pending, or a PDCCH indicating a new transmission addressed to a C-RNTI of a MAC entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble, where the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern.

In some example embodiments, the terminal device comprises circuitry configured to:if none of the plurality of conditions is met and a drx-onDurationTimer is running, switch back to the first PDCCH monitoring pattern.

In some example embodiments, the terminal device comprises circuitry configured to:once the drx-InactivityTimer is started, keep performing the PDCCH monitoring according to the second PDCCH monitoring pattern until a next DRX cycle.

In some example embodiments, the terminal device comprises circuitry configured to:receive, from a network device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the terminal device comprises circuitry configured to: receive, from a network device, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the terminal device comprises circuitry configured to: receive, from the network device, a second indication of the second PDCCH monitoring pattern.

In some example embodiments, a terminal device comprises circuitry configured to:determine a duration within a periodicity for a PDCCH monitoring; perform the PDCCH monitoring according to a first PDCCH monitoring pattern within the duration; and if a PDCCH is detected in a slot of the duration, switch to a second PDCCH monitoring pattern to perform the PDCCH monitoring within the duration, the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the terminal device comprises circuitry configured to: receive, from the network device, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, a network device comprises circuitry configured to:determine a first PDCCH monitoring pattern and a second PDCCH monitoring pattern for a PDCCH monitoring, the second PDCCH monitoring pattern is denser than the first PDCCH monitoring pattern; and transmit, to a terminal device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In some example embodiments, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the network device comprises circuitry configured to: transmit, to the terminal device, a first indication of the first PDCCH monitoring pattern.

In some example embodiments, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the network device comprises circuitry configured to: transmit, to the terminal device, a second indication of the second PDCCH monitoring pattern.

FIG. 13 illustrates a simplified block diagram of a device 1300 that is suitable for implementing embodiments of the present disclosure. The device 1300 can be considered as a further example implementation of the terminal device 420, and the network device 410 as shown in FIG. 4. Accordingly, the device 1300 can be implemented at or as at least a part of the terminal device 420, or the network device 410.

As shown, the device 1300 includes a processor 1310, a memory 1320 coupled to the processor 1310, a suitable transmitter (TX) and receiver (RX) 1340 coupled to the processor 1310, and a communication interface coupled to the TX/RX 1340. The memory 1310 stores at least a part of a program 1330. The TX/RX 1340 is for bidirectional communications. The TX/RX 1340 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this disclosure may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2 interface for bidirectional communications between eNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the eNB, Un interface for communication between the eNB and a relay node (RN) , or Uu interface for communication between the eNB and a terminal device.

The program 1330 is assumed to include program instructions that, when executed by the associated processor 1310, enable the device 1300 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGS. 4-12. The embodiments herein may be implemented by computer software executable by the processor 1310 of the device 1300, or by hardware, or by a combination of software and hardware. The processor 1310 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1310 and memory 1320 may form processing means 1350 adapted to implement various embodiments of the present disclosure.

The memory 1320 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1320 is shown in the device 1300, there may be several physically distinct memory modules in the device 1300. The processor 1310 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1300 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

In summary, embodiments of the present disclosure may provide the following solutions.

The present disclosure provides a method of communication, comprises: performing, at a terminal device, a physical downlink control channel (PDCCH) monitoring according to a first PDCCH monitoring pattern; and switching to a second PDCCH monitoring pattern based on at least one of a plurality of conditions: a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group, a ra-ContentionResolutionTimer is running, a msgB-ResponseWindow is running, a scheduling request is sent on a physical uplink control channel (PUCCH) and is pending, or a PDCCH indicating a new transmission addressed to a cell-radio network temporary identity (C-RNTI) of a media access control (MAC) entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern.

In one embodiment, the method as above, the first PDCCH monitoring pattern corresponds to a first search space or a first search space group, and the second PDCCH monitoring pattern corresponds to a second search space or a second search space group.

In one embodiment, the method as above, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern are two different patterns of a same search space.

In one embodiment, the method as above, further comprising: in accordance with a determination that none of the plurality of conditions is met and a drx-onDurationTimer is running, switching back to the first PDCCH monitoring pattern.

In one embodiment, the method as above, further comprising: once the drx-InactivityTimer is started, keeping performing the PDCCH monitoring according to the second PDCCH monitoring pattern until a next DRX cycle.

In one embodiment, the method as above, further comprising: receiving, from a network device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In one embodiment, the method as above, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the method further comprises: receiving, from the network device, a first indication of the first PDCCH monitoring pattern.

In one embodiment, the method as above, the first indication is transmitted via at least one of: a radio resource control (RRC) message, downlink control information (DCI) , a wake up signal, or a medium access control (MAC) control element (CE) .

In one embodiment, the method as above, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the method further comprises: receiving, from the network device, a second indication of the second PDCCH monitoring pattern.

In one embodiment, the method as above, the second indication is transmitted via at least one of: an RRC message, a DCI, a wake up signal, or a MAC CE.

In one embodiment, the method as above, the configuration information is transmitted via an RRC message.

In one embodiment, the method as above, the second PDCCH monitoring pattern is one of a plurality of patterns associated with the plurality of conditions.

In one embodiment, the method as above, the first PDCCH monitoring pattern and the second PDCCH monitoring pattern have different time domain parameters comprising at least one of: a periodicity, a slot offset, a duration, or monitoring symbols within a slot.

In one embodiment, the method as above, the first PDCCH monitoring pattern is configured for a drx-onDurationTimer of a DRX operation.

In one embodiment, the method as above, the second PDCCH monitoring pattern comprises a continuous monitoring pattern.

The present disclosure provides a method of communication, comprises: determining, at a terminal device, a duration within a periodicity for a physical downlink control channel (PDCCH) monitoring; and performing the PDCCH monitoring according to a first PDCCH monitoring pattern within the duration; and in accordance with a determination that a PDCCH is detected in a slot of the duration, switching to a second PDCCH monitoring pattern to perform the PDCCH monitoring within the duration, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern.

The present disclosure provides a method of communication, comprises: determining, at a network device, a first PDCCH monitoring pattern and a second PDCCH monitoring pattern for a physical downlink control channel (PDCCH) monitoring, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern; and transmitting, to a terminal device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern.

In one embodiment, the method as above, the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the method further comprises: transmitting, to the terminal device, a first indication of the first PDCCH monitoring pattern.

In one embodiment, the method as above, the first indication is transmitted via at least one of: an RRC message, downlink control information (DCI) , a wake up signal, or a medium access control (MAC) control element (CE) .

In one embodiment, the method as above, the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the method further comprises: transmitting, to a terminal device, a second indication of the second PDCCH monitoring pattern.

In one embodiment, the method as above, the second PDCCH monitoring pattern is one of a plurality of patterns associated with a plurality of conditions comprising: a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running at the terminal device, a drx-RetransmissionTimerDL is running on a serving cell in the DRX group at the terminal device, a drx-RetransmissionTimerUL is running on the serving cell in the DRX group at the terminal device, a drx-RetransmissionTimerSL is running on the serving cell in the DRX group at the terminal device, a ra-ContentionResolutionTimer is running at the terminal device, a msgB-ResponseWindow is running at the terminal device, a scheduling request is sent on a physical uplink control channel (PUCCH) by the terminal device and is pending, and a PDCCH indicating a new transmission addressed to a cell-radio network temporary identity (C-RNTI) of a media access control (MAC) entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble.

The present disclosure provides a terminal device, comprising: a processor; and a memory storing computer program codes; the memory and the computer program codes configured to, with the processor, cause the terminal device to perform the method implemented at the terminal device discussed above.

The present disclosure provides a network device, comprising: a processor; and a memory storing computer program codes; the memory and the computer program codes configured to, with the processor, cause the network device to perform the method implemented at the network device discussed above.

The present disclosure provides a computer readable medium having instructions stored thereon, the instructions, when executed by a processor of an apparatus, causing the apparatus to perform the method implemented at a terminal device or a network device discussed above.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects 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. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGS. 4-12. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A method of communication, comprising:

performing, at a terminal device, a physical downlink control channel (PDCCH) monitoring according to a first PDCCH monitoring pattern; and

switching to a second PDCCH monitoring pattern based on at least one of a plurality of conditions:

a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running,

a drx-RetransmissionTimerDL is running on a serving cell in the DRX group,

a drx-RetransmissionTimerUL is running on the serving cell in the DRX group,

a drx-RetransmissionTimerSL is running on the serving cell in the DRX group,

a ra-ContentionResolutionTimer is running,

a msgB-ResponseWindow is running,

a scheduling request is sent on a physical uplink control channel (PUCCH) and is pending, or

a PDCCH indicating a new transmission addressed to a cell-radio network temporary identity (C-RNTI) of a media access control (MAC) entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble,

the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern, the second PDCCH monitoring pattern being one of a plurality of patterns associated with the plurality of conditions.
The method of claim 1, wherein the first PDCCH monitoring pattern corresponds to a first search space or a first search space group, and the second PDCCH monitoring pattern corresponds to a second search space or a second search space group, or wherein the first PDCCH monitoring pattern and the second PDCCH monitoring pattern are two different patterns of a same search space.
The method of claim 1, further comprising:

in accordance with a determination that none of the plurality of conditions is met and a drx-onDurationTimer is running, switching back to the first PDCCH monitoring pattern.
The method of claim 1, further comprising:

once the drx-InactivityTimer is started, keeping performing the PDCCH monitoring according to the second PDCCH monitoring pattern until a next DRX cycle.
The method of claim 1, further comprising:

receiving, from a network device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern, wherein the configuration information is transmitted via an RRC message.
The method of claim 5, wherein the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the method further comprises:

receiving, from the network device, a first indication of the first PDCCH monitoring pattern,

wherein the first indication is transmitted via at least one of:

a radio resource control (RRC) message,

downlink control information (DCI) ,

a wake up signal, or

a medium access control (MAC) control element (CE) .
The method of claim 6, wherein the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the method further comprises:

receiving, from the network device, a second indication of the second PDCCH monitoring pattern, wherein the second PDCCH monitoring pattern comprises a continuous monitoring pattern,

wherein the second indication is transmitted via at least one of:

an RRC message,

a DCI,

a wake up signal, or

a MAC CE.
The method of claim 1, wherein the first PDCCH monitoring pattern is configured for a drx-onDurationTimer of a DRX operation, and wherein the first PDCCH monitoring pattern and the second PDCCH monitoring pattern have different time domain parameters comprising at least one of:

a periodicity,

a slot offset,

a duration, or

monitoring symbols within a slot.
A method of communication, comprising:

determining, at a terminal device, a duration within a periodicity for a physical downlink control channel (PDCCH) monitoring; and

performing the PDCCH monitoring according to a first PDCCH monitoring pattern within the duration; and

in accordance with a determination that a PDCCH is detected in a slot of the duration, switching to a second PDCCH monitoring pattern to perform the PDCCH monitoring within the duration, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern.
The method of claim 9, further comprising:

receiving, from a network device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern, wherein the configuration information is transmitted via an RRC message.
The method of claim 10, wherein the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the method further comprises:

receiving, from the network device, a first indication of the first PDCCH monitoring pattern,

wherein the first indication is transmitted via at least one of:

a radio resource control (RRC) message,

downlink control information (DCI) ,

a wake up signal, or

a medium access control (MAC) control element (CE) .
The method of claim 11, wherein the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the method further comprises:

receiving, from the network device, a second indication of the second PDCCH monitoring pattern, wherein the second PDCCH monitoring pattern comprises a continuous monitoring pattern,

wherein the second indication is transmitted via at least one of:

an RRC message,

a DCI,

a wake up signal, or

a MAC CE.
A method of communication, comprising:

determining, at a network device, a first PDCCH monitoring pattern and a second PDCCH monitoring pattern for a physical downlink control channel (PDCCH) monitoring, the second PDCCH monitoring pattern being denser than the first PDCCH monitoring pattern; and

transmitting, to a terminal device, configuration information indicating at least one of the first PDCCH monitoring pattern or the second PDCCH monitoring pattern, wherein the configuration information is transmitted via an RRC message.
The method of claim 13, wherein the configuration information indicates a list of PDCCH monitoring patterns comprising the first PDCCH monitoring pattern, and the method further comprises:

transmitting, to the terminal device, a first indication of the first PDCCH monitoring pattern,

wherein the first indication is transmitted via at least one of:

an RRC message,

downlink control information (DCI) ,

a wake up signal, or

a medium access control (MAC) control element (CE) .
The method of claim 14, wherein the list of PDCCH monitoring patterns comprises the second PDCCH monitoring pattern, and the method further comprises:

transmitting, to a terminal device, a second indication of the second PDCCH monitoring pattern,

wherein the second indication is transmitted via at least one of:

an RRC message,

a DCI,

a wake up signal, or

a MAC CE.
The method of claim 13, wherein the first PDCCH monitoring pattern corresponds to a first search space or a first search space group, and the second PDCCH monitoring pattern corresponds to a second search space or a second search space group, or wherein the first PDCCH monitoring pattern and the second PDCCH monitoring pattern are two different patterns of a same search space.
The method of claim 13, wherein the second PDCCH monitoring pattern comprises a continuous monitoring pattern, and wherein the second PDCCH monitoring pattern is one of a plurality of patterns associated with a plurality of conditions comprising:

a drx-InactivityTimer configured for a discontinuous reception (DRX) group is running at the terminal device,

a drx-RetransmissionTimerDL is running on a serving cell in the DRX group at the terminal device,

a drx-RetransmissionTimerUL is running on the serving cell in the DRX group at the terminal device,

a drx-RetransmissionTimerSL is running on the serving cell in the DRX group at the terminal device,

a ra-ContentionResolutionTimer is running at the terminal device,

a msgB-ResponseWindow is running at the terminal device,

a scheduling request is sent on a physical uplink control channel (PUCCH) by the terminal device and is pending, and

a PDCCH indicating a new transmission addressed to a cell-radio network temporary identity (C-RNTI) of a media access control (MAC) entity has not been received after a successful reception of a random access response for a random access preamble not selected by the MAC entity among a contention-based random access preamble.
The method of claim 13, wherein the first PDCCH monitoring pattern is configured for a drx-onDurationTimer of a DRX operation, and wherein the first PDCCH monitoring pattern and the second PDCCH monitoring pattern have different time domain parameters comprising at least one of:

a periodicity,

a slot offset,

a duration, or

monitoring symbols within a slot.
A terminal device comprising:

a processor; and

a memory storing computer program codes;

the memory and the computer program codes configured to, with the processor, cause the terminal device to perform the method according to any of claims 1-12.
A network device comprising:

a processor; and

a memory storing computer program codes;

the memory and the computer program codes configured to, with the processor, cause the network device to perform the method according to any of claims 13-18.
A computer readable medium having instructions stored thereon, the instructions, when executed by a processor of an apparatus, causing the apparatus to perform the method according to any of claims 1-18.