WO2025020031A1

WO2025020031A1 - Devices and methods of communication

Info

Publication number: WO2025020031A1
Application number: PCT/CN2023/108827
Authority: WO
Inventors: Rao SHI; Gang Wang
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2023-07-24
Filing date: 2023-07-24
Publication date: 2025-01-30
Anticipated expiration: 2026-01-24

Abstract

Embodiments of the present disclosure relate to devices and methods of communication. In one aspect, upon reception of an LPWUS from a network device in a first mode, a terminal device performs a PDCCH monitoring in a second mode. If no data related information is received in the second mode, the terminal device performs an LPWUS monitoring in the first mode. In this way, fallback of an LPWUS mode from a PDCCH monitoring may be achieved and unnecessary power consumption for PDCCH monitoring may be reduced.

Description

DEVICES AND METHODS OF COMMUNICATION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices and computer storage media of communication for a lower-power wake-up signal (LPWUS) .

BACKGROUND

Currently, it has been proposed to use main radio to describe a regular communication device performing normal radio resource control (RRC) states and additionally design an LPWUS receiver to monitor an LPWUS for turn-on of the main radio. When a terminal device is not receiving a service, the terminal device may enter an LPWUS mode during which the main radio is turned off and the LPWUS receiver is turned on to monitor the LPWUS. When an LPWUS is received, the terminal device may turn on the main radio and turn off the LPWUS receiver. However, an LPWUS mechanism is still incomplete and needs to be further developed.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage media of communication for LPWUS.

In a first aspect, there is provided a terminal device. The terminal device comprises a processor configured to cause the terminal device to: receive, from a network device, an LPWUS in a first mode; perform a physical downlink control channel (PDCCH) monitoring in a second mode; and in accordance with a determination that no data related information is received in the second mode, perform an LPWUS monitoring in the first mode.

In a second aspect, there is provided a terminal device. The terminal device comprises a processor configured to cause the terminal device to: receive, from a network device, an LPWUS in a first mode; initiate a random access procedure in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and perform an LPWUS monitoring in the first mode based on a response to the random access procedure from the network device.

In a third aspect, there is provided a network device. The network device comprises a processor configured to cause the network device to: transmit an LPWUS to a terminal device in a first mode; perform a random access procedure initiated by the terminal device in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and determine a response to the random access procedure.

In a fourth aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a network device, an LPWUS in a first mode; perform a PDCCH monitoring in a second mode; and in accordance with a determination that no data related information is received in the second mode, performing an LPWUS monitoring in the first mode.

In a fifth aspect, there is provided a method of communication. The method comprises: receiving, at a terminal device and from a network device, an LPWUS in a first mode; initiating a random access procedure in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and performing an LPWUS monitoring in the first mode based on a response to the random access procedure from the network device.

In a sixth aspect, there is provided a method of communication. The method comprises: transmit, at a network device, an LPWUS to a terminal device in a first mode; performing a random access procedure initiated by the terminal device in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and determining a response to the random access procedure.

In a seventh aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method according to any of the fourth to sixth aspects 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 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. 1A illustrates an example communication network in which some embodiments of the present disclosure can be implemented;

FIG. 1B illustrates an example structure of a terminal device in which some embodiments of the present disclosure can be implemented;

FIG. 1C illustrates a diagram illustrating example application scenarios of an LPWUS mechanism in a connected state in which some embodiments of the present disclosure can be implemented;

FIG. 1D illustrates a diagram illustrating example application scenarios of an LPWUS mechanism in an idle or inactive state in which some embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a schematic diagram illustrating a process of communication according to embodiments of the present disclosure;

FIG. 3A illustrates a schematic diagram illustrating an example fallback of an LPWUS mode based on active time of a discontinuous reception (DRX) cycle according to embodiments of the present disclosure;

FIG. 3B illustrates a schematic diagram illustrating an example fallback of an LPWUS mode based on downlink control information with cyclic redundancy check scrambled by power saving-radio network temporary identifier (DCP) according to embodiments of the present disclosure;

FIG. 3C illustrates a schematic diagram illustrating an example fallback of an LPWUS mode based on a timer according to embodiments of the present disclosure;

FIG. 4 illustrates a schematic diagram illustrating another process of communication according to embodiments of the present disclosure;

FIG. 5 illustrates an example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates another example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates still an example method of communication implemented at a network device in accordance with some embodiments of the present disclosure; and

FIG. 8 is 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 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 limitations as to the scope of the disclosure. The disclosure 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.

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the 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 incorporate 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 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.

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 or the network device may work on several frequency ranges, e.g. FR1 (410 MHz to 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 devices 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, channel emulator.

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 or 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.

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 ‘at least in part based 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 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.

In the context of the present disclosure, the term “aconnected state” may be interchangeably used with “an RRC_CONNECTED state” , the term “an idle state” may be interchangeably used with “an RRC_IDLE state” , and the term “an inactive state” may be interchangeably used with “an RRC_INACTIVE state” .

In the context of the present disclosure, the term “turn on” may be interchangeably used with “activated” , “wake up” , “switch on” , “state transition” or “warm up” . In the context of the present disclosure, the term “turn off” may be interchangeably used with “deactivated” , “sleep” , “switch off” , “state transition” , or “warm down” . In the context of the present disclosure, the term “always-on monitoring” may be interchangeably used with “continuous monitoring” , and the term “duty-cycle monitoring” may be interchangeably used with “periodic monitoring” . In the context of the present disclosure, the term “DCP” may also be referred to as “downlink control information for power saving” .

In the context of the present disclosure, for an inactive or idle state, the term “LPWUS mode” may mean that UE monitors an LPWUS within an inactive or idle state while a main radio is in ultra-deep-sleep or is non-active or is turned off. For a connected state, the term “LPWUS mode” may mean that UE monitors an LPWUS within a connected state while a main radio is in light-sleep or micro-sleep or is non-active or is turned off. The term “LPWUS mode” may be interchangeably used with “LPWUS state” or any other suitable names.

In general, during an LPWUS mode, a main radio may stay in a sleep mode. A terminal device may still stay in any RRC state (e.g., an idle or inactive or connected state) but may not perform regular operations in those RRC states. The terminal device may only need to monitor an LPWUS or perform some actions related to an LPWUS mode, e.g., synchronization and/or measurement in an LPWUS mode.

In the context of the present disclosure, the term “LPWUS” is used to describe a signal sent by a network in an LPWUS mode and monitored by a low power receiver of a terminal device. The term “LPWUS” may be interchangeably used with “ultra-low-power wake up signal” or “wake up signal” or any other suitable names.

In the context of the present disclosure, the term “active time of a DRX cycle” may also be referred to as “DRX active time” or “active time window” . When a terminal device is in DRX active time, the terminal device starts performing a PDCCH monitoring. The term “non-active time of a DRX cycle” may also be referred to as “DRX non-active time” or “sleep time” or “sleep time window” . Compared with the DRX active time, the DRX non-active time means that a terminal device works in a sleep mode and is not required to perform a PDCCH monitoring.

When DRX is configured, active time for serving cells in a DRX group includes: the time while drx-onDurationTimer is running; or the time while drx-InactivityTimer is running; or the time while drx-RetransmissionTimerDL is running; or the time while drx-RetransmissionTimerUL is running; or the time while ra-ContentionResultionTimer is running.

The fifth generation (5G) devices consume tens of milliwatts in an idle or inactive state and hundreds of milliwatts in a connected state. Designing to prolong battery life is a necessity for improving energy efficiency as well as for better user experience. To meet battery life requirements, an enhanced discontinuous reception (eDRX) cycle with a large value is expected to be used. The eDRX cycle may result in high latency and thus is not suitable for services with requirements of both long battery life and low latency. For example, in fire detection and extinguishment use case, a long eDRX cycle cannot meet delay requirements. That is, eDRX is apparently not suitable for latency-critical use cases. Thus, it is expected to study an ultra-low power mechanism that can support low latency, e.g., lower than eDRX latency.

As mentioned above, an LPWUS mechanism has been proposed. In the LPWUS mechanism, a main radio is used to describe a regular communication device performing normal RRC states and an LPWUS receiver is additionally designed to monitor an LPWUS for turn-on of the main radio. When a terminal device is not receiving service, the terminal device may enter an LPWUS mode during which the main radio is turned off and the LPWUS receiver is turned on to monitor the LPWUS. The purpose of the LPWUS mechanism is also for power saving of the terminal device.

However, it is difficult to achieve a UE-specific LPWUS design due to low complexity. That means multiple UEs need to monitor the same LPWUS for possible data coming.

In some scenarios where an LPWUS is applied for UE in a connected state, upon reception of an LPWUS, UE may use a DRX cycle to monitor PDCCH in a normal or activated connected state. In this case, if the LPWUS is not intended for this UE (e.g., LPWUS carrying a notification for other UEs) , a false alarm issue happens. Unnecessary power consumption (i.e., unnecessary monitoring) will be caused to this UE.

In some scenarios where an LPWUS is applied for UE in an idle or inactive state, upon reception of an LPWUS, UE may directly initiate a random access to establish or resume an RRC connection. This may avoid a paging or paging early indication (PEI) procedure for better latency, power saving, etc. In this case, if the LPWUS is not intended for this UE ( (e.g., LPWUS carrying a notification for other UEs) , a false alarm issue happens. Unnecessary power consumption (i.e., unnecessary random access) will also be caused to this UE.

In view of this, embodiments of the present disclosure provide solutions of communication so as to achieve fallback of an LPWUS mode and reduce unnecessary power consumption. In one aspect, upon reception of an LPWUS from a network device in a first mode, a terminal device may perform a PDCCH monitoring in a second mode. If no data related information is received in the second mode, the terminal device may perform an LPWUS monitoring in the first mode. In this way, fallback of an LPWUS mode from a PDCCH monitoring may be achieved and unnecessary power consumption for PDCCH monitoring may be reduced.

In another aspect, upon reception of an LPWUS from a network device in a first mode, a terminal device may initiate a random access procedure in a second mode and indicate that the random access procedure is initiated due to reception of the LPWUS. Thereby, the network device may determine whether a false alarm issue happens, and then determine a response to the random access procedure. Based on the response to the random access procedure from the network device, the terminal device may perform an LPWUS monitoring in the first mode. In this way, fallback of an LPWUS mode from a random access procedure may be achieved and unnecessary power consumption for random access may be reduced.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

EXAMPLE OF COMMUNICATION NETWORK

FIG. 1A illustrates a schematic diagram of an example communication network 100A in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1A, the communication network 100A may comprise a terminal device 110 and network device 120. The network device 120 may provide a serving cell (also referred to as a cell herein) 121 to serve one or more terminal devices. In this example, the terminal device 110 is shown as being located in the cell 121 and served by the network device 120.

As shown in FIG. 1A, the terminal device 110 and the network device 120 may communicate with each other via a channel such as a wireless communication channel. The communications in the communication network 100A may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. 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.

It is to be understood that the number of devices or cells in FIG. 1A is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication network 100A may include any suitable number of network devices and/or terminal devices and/cells adapted for implementing implementations of the present disclosure.

FIG. 1B illustrates a diagram 100B illustrating an example structure of a terminal device in which some embodiments of the present disclosure can be implemented. For convenience, FIG. 1B is described in connection with the terminal device 110 of FIG. 1A.

As shown in FIG. 1B, the terminal device 110 may comprise an LPWUS receiver 141 and a main radio 142. The LPWUS receiver 141 is configured to monitor an LPWUS. The main radio 142 is configured as a regular communication device performing normal RRC states. It is to be understood that the LPWUS receive and the main radio may have any other suitable names.

In some embodiments, the LPWUS receiver 141 may detect the LPWUS indicating turn-off of the main radio 142, and trigger the main radio 142 to enter a turn-off or deep-sleep state. In the turn-off or deep-sleep state, the terminal device 110 is not required to process a RRC idle or inactive or connected state procedure. In some embodiments, the LPWUS receiver 141 may detect the LPWUS indicating turn-on of the main radio 142, and trigger the main radio 142 to enter a turn-on state. In the turn-on state, the main radio 142 may perform a PDCCH monitoring or perform a paging monitoring or directly initiate a random access (RA) procedure.

FIG. 1C illustrates a diagram 100C illustrating example application scenarios of an LPWUS mechanism in a connected state in which some embodiments of the present disclosure can be implemented. In this example, a DRX cycle may be configured for PDCCH monitoring, and the DRX cycle may comprise active time and sleep time.

As shown in FIG. 1C, in scenario 150, periodic monitoring of an LPWUS may be configured. As shown, if an LPWUS is received at an LPWUS monitoring occasion 151, a PDCCH monitoring may be performed during active time 152. If no LPWUS is received at an LPWUS monitoring occasion 153, a PDCCH monitoring may be not performed during active time 154.

In scenario 150’ , periodic monitoring of an LPWUS may be configured. As shown, if an LPWUS is received at an LPWUS monitoring occasion 151’ , a DCP monitoring may be performed. If a DCP (e.g., the DCP comprises a wake-up indication bit of 1) indicating a start of a PDCCH monitoring is received, a PDCCH monitoring may be performed during active time 152’ . If no LPWUS is received at an LPWUS monitoring occasion 153’ , a DCP monitoring may be not performed before active time 154’ and a PDCCH monitoring may be not performed during active time 154’ .

In scenario 160, always-on monitoring of an LPWUS may be configured. As shown, an LPWUS may be always monitored until the LPWUS is received. In this example, the LPWUS is received at a timing A. A PDCCH monitoring is skipped until the timing A. That is, the PDCCH monitoring is performed after the timing A during active time 161.

In these scenarios, if the LPWUS is not intended for current UE (e.g., LPWUS carrying a notification for other UEs) , a false alarm issue happens. Unnecessary power consumption for PDCCH monitoring may be caused to this UE.

FIG. 1D illustrates a diagram 100D illustrating example application scenarios of an LPWUS mechanism in an idle or inactive state in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1D, in scenario 170, if an LPWUS is received, paging monitoring at paging occasion (POs) may be performed. Optionally, a synchronization signal and physical broadcast channel block (SSB) measurement and synchronization may be performed before the paging monitoring. If a paging to current UE is received on a PO, the current UE may transmit a preamble on a physical random access channel (PRACH) to initiate an RA procedure. Optionally, an SSB measurement and synchronization may also be performed before the RA procedure.

In scenario 180, if an LPWUS is received, PEI monitoring may be performed. Optionally, an SSB measurement and synchronization may be performed before the PEI monitoring. If a PEI indicating enabling of a paging monitoring is received, a paging monitoring may be performed at POs. If a paging to current UE is received on a PO, the current UE may transmit a preamble on a PRACH to initiate an RA procedure. Optionally, an SSB measurement and synchronization may also be performed before the RA procedure.

In scenario 190, if an LPWUS is received, current UE may directly transmit a preamble on a PRACH to initiate an RA procedure. Optionally, an SSB measurement and synchronization may be performed before the RA procedure.

In these scenarios, if the LPWUS is not intended for the current UE (e.g., LPWUS carrying a notification for other UEs) , a false alarm issue happens. Unnecessary power consumption for RA may be caused to this UE.

In view of this, embodiments of the present disclosure provide solutions of communication so as to achieve fallback of an LPWUS mode and reduce unnecessary power consumption. These solutions will be described with reference to FIGs. 2 to 4 below.

EXAMPLE IMPLEMENTATION OF FALLBACK FROM PDCCH MONITORING

FIG. 2 illustrates a schematic diagram illustrating a process 200 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to FIGs. 1A and 1B. The process 200 may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1A. It is to be understood that the steps and the order of the steps in FIG. 2 are merely for illustration, and not for limitation. For example, the order of the steps may be changed. Some of the steps may be omitted or any other suitable additional steps may be added.

As shown in FIG. 2, the network device 120 may transmit 210 a LPWUS configuration to the terminal device 110. In some embodiments, the network device 120 may transmit the LPWUS configuration in system information (SI) or in any other suitable ways. In some embodiments, the LPWUS configuration may indicate one or more occasions for LPWUS monitoring. In some embodiments, periodic monitoring may be configured for the LPWUS monitoring. In some embodiments, always-on monitoring may be configured for the LPWUS monitoring. It is to be understood that the LPWUS configuration may also comprise any other suitable information, and may also be transmitted in any other suitable ways.

Based on the LPWUS configuration, the terminal device 110 may perform 220 an LPWUS monitoring in a first mode. In the first mode, the main radio 142 of the terminal device 110 is turned off and the LPWUS receiver 141 of the terminal device 110 is turned on. In the context of the present disclosure, the first mode may also be referred to as an LPWUS mode or state, a sleep mode or state, or an ultra-deep sleep mode or state.

Continuing to refer to FIG. 2, the network device 120 may transmit 230 an LPWUS to the terminal device 110 in the LPWUS mode. Upon reception of the LPWUS, the terminal device 110 may perform 235 a PDCCH monitoring in a second mode (e.g., activate the main radio 142) . In the second mode, the main radio 142 of the terminal device 110 is turned on and the LPWUS receiver 141 of the terminal device 110 is turned off. In some embodiments, the second mode may be a connected state.

If no data related information is received in the second mode, the terminal device 110 may perform 240 an LPWUS monitoring in the first mode. In some embodiments, the data related information may comprise a PDCCH transmission. In some embodiments, the data related information may comprise downlink control information (DCI) . In some embodiments, the data related information may comprise a downlink assignment. In some embodiments, the data related information may comprise a medium access control (MAC) protocol data unit (PDU) or an MAC service data unit (SDU) . In some embodiments, the data related information may comprise a transport block (TB) . In some embodiments, the data related information may comprise a physical downlink shared channel (PDSCH) transmission. It is to be understood that any other data related information may also be feasible.

That is, if no data related information is received, the terminal device 110 may fallback to an LPWUS mode (e.g., deactivate the main radio 142) to monitor an LPWUS again. If data related information is received, the terminal device 110 may keep in the second mode to perform related operations. In this way, unnecessary PDCCH monitoring may be reduced and power consumption may be saved.

For illustration, some example embodiments will be described in connection with Embodiments 1 to 4 below.

Embodiment 1

In this embodiment, the terminal device 110 may perform the PDCCH monitoring based on a DRX cycle. With reference to FIG. 2, if no data related information is received within a predetermined number of active time windows of DRX cycles, the terminal device 110 may determine 241 that no data related information is received and enter the first mode to perform an LPWUS monitoring.

In some embodiments, if no data related information is received within the predetermined number of active time windows of DRX cycles, the terminal device 110 may suspend or stop using the DRX cycle for the PDCCH monitoring.

In some embodiments, the predetermined number may be 1. That is, if no data related information is received within active time of a DRX cycle, the terminal device 110 may enter the first mode to monitor an LPWUS. It is to be understood that the predetermined number may be any suitable numbers. In some embodiments, the predetermined number may be configured by the network device 120. In some embodiments, the predetermined number may be predefined.

FIG. 3A illustrates a schematic diagram 300A illustrating an example fallback of an LPWUS mode based on active time of a DRX cycle according to embodiments of the present disclosure. As shown in FIG. 3A, upon reception of an LPWUS at a timing B, the main radio 142 may warm up to perform a PDCCH monitoring based on a DRX cycle. In some embodiments where the predetermined number is 1, if no data related information is received during an active time window 311, the terminal device 110 may enter an LPWUS mode (e.g., deactivate the main radio 142) to monitor an LPWUS.

In some embodiments where the predetermined number is 2, if no data related information is received during the active time window 311, the terminal device 110 continue to perform the PDCCH monitoring during an active time window 312. If no data related information is received during the active time window 312 either, the terminal device 110 may enter an LPWUS mode to monitor an LPWUS.

For illustration, an example procedure may be described as below.

Upon LPWUS detection, UE shall:

1> if LPWUS is received and indicate this UE to start to monitor PDCCH (or operate DRX) :

2> use DRX to monitor the PDCCH.

When DRX is configured or used, the MAC entity (of this UE) shall:

1> if a DRX group is in Active Time:

2> monitor the PDCCH on the Serving Cells in this DRX group;

2> if the PDCCH indicates a DL transmission:

2> if LPWUS is configured for this UE (or UE monitors PDCCH during this DRX Active Time due to LPWUS detection) and the Active Time (e.g., drx-onDurationTimer) is expired:

3> if no any PDCCH or downlink assignment or MAC PDU is received within this Active Time:

4> suspend or stop to use the DRX;

4> not monitor a PDCCH on the Serving Cells;

4> enter an LPWUS mode (i.e., monitors an LPWUS again) .

It is to be understood that the above example procedure is merely for illustration and is not intended for limitation.

In this way, based on DRX active time, a terminal device may determine that no any data related information arrives at a terminal device. Thus, the terminal device is unnecessary to stay in a connected state any longer, and may fall back to an LPWUS mode for power saving.

Embodiment 2

In this embodiment, a DCP monitoring is configured for the terminal device 110. The terminal device 110 may perform the DCP monitoring before a PDCCH monitoring and perform the PDCCH monitoring based on a DRX cycle if DCP indicating a start of the PDCCH monitoring is received. In some embodiments, if DCP indicates a start of a DRX on-duration timer, the start of the PDCCH monitoring is indicated by the DCP. That is, if the DCP indicating the start of the DRX on-duration timer is received, the terminal device 110 may perform the PDCCH monitoring based on the DRX cycle.

With reference to FIG. 2, if the DCP indicating the start of the PDCCH monitoring is not received, the terminal device 110 may determine 242 that no data related information is received and enter the first mode to perform an LPWUS monitoring.

In some embodiments, if DCP is received for a predetermined number of times and the DCP indicates that no timer for an active time window of the DRX cycle is started (e.g., the DCP comprises a wake-up indication bit of 0) , the terminal device 110 may determine that no data related information is received and enter the first mode to perform an LPWUS monitoring. In some embodiments, if no DCP is received, the terminal device 110 may determine that no data related information is received and enter the first mode to perform an LPWUS monitoring. In these embodiments, the terminal device 110 may suspend or stop using the DRX cycle for the PDCCH monitoring.

In some embodiments, the predetermined number of times may be 1. That is, if DCP comprising a wake-up indication bit of 0 is received, the terminal device 110 may enter the first mode to monitor an LPWUS. It is to be understood that the predetermined number of times may be any suitable numbers. In some embodiments, the predetermined number of times may be configured by the network device 120. In some embodiments, the predetermined number of times may be predefined.

FIG. 3B illustrates a schematic diagram 300B illustrating an example fallback of an LPWUS mode based on DCP according to embodiments of the present disclosure. As shown by reference sign 320 in FIG. 3B, upon reception of an LPWUS at a timing C, the main radio 142 may warm up to perform a DCP monitoring.

In some embodiments where the predetermined number of times is 1, if DCP comprising a wake-up indication bite of 0 is received at timing D, the terminal device 110 may enter an LPWUS mode (e.g., deactivate the main radio 142) to monitor an LPWUS, and a PDCCH monitoring during active time 321 is cancelled.

In some embodiments where the predetermined number of times is 2, if DCP comprising a wake-up indication bite of 0 is received at timing D, the terminal device 110 may cancel the PDCCH monitoring during active time 321 and continue to perform the DCP monitoring in the connected state. If DCP comprising a wake-up indication bite of 0 is received again at timing E, the terminal device 110 may enter an LPWUS mode to monitor an LPWUS. The PDCCH monitoring during active time 322 may also be cancelled.

As shown by reference sign 320’ in FIG. 3B, upon reception of an LPWUS, the main radio 142 may warm up to perform a DCP monitoring. If no DCP is received, the terminal device 110 may cancel the PDCCH monitoring during active time 321’ and may enter an LPWUS mode to monitor an LPWUS.

For illustration, an example procedure may be described as below.

Upon LPWUS detection, the UE shall:

2> use DRX to monitor the PDCCH.

When DRX is configured or used, the MAC entity (of this UE) shall:

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:

3> if DCP indication associated with the current DRX cycle received from lower layer indicated to start drx-onDurationTimer; or

3> if all DCP occasion (s) in time domain, associated with the current DRX cycle occurred in Active Time considering …; 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.

3> if LPWUS is configured for this UE (or UE uses DRX due to LPWUS detection) and DCP indication associated with the current DRX cycle received from lower layer indicated to not start drx-onDurationTimer (i.e., value “0” ) ; or

3> if LPWUS is configured for this UE (or UE uses DRX due to LPWUS detection) and DCP indication associated with the current DRX cycle has not been received from lower layers:

4> suspend or stop to use the DRX;

4> not monitor PDCCH on the Serving Cells;

4> enters LPWUS mode (i.e., monitoring LPWUS again) ;

2> else:

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

In this way, based on DCP, a terminal device may determine that no any data related information arrives at a terminal device. Thus, the terminal device is unnecessary to stay in a connected state any longer, and may fall back to an LPWUS mode for power saving.

Embodiment 3

In this embodiment, if the LPWUS is received or the main radio 142 of the terminal device 110 is turned on (e.g., totally warmed up) , the terminal device 110 may start a timer. Continuing to refer to FIG. 2, if the timer expires, the terminal device 110 may determine 243 that no data related information is received and enter the first mode to monitor an LPWUS.

In some embodiments, if the LPWUS is received, the terminal device 110 may enter the second mode to perform a PDCCH monitoring based on a DRX cycle. In some embodiments, if data related information is received in the second mode, the terminal device 110 may stop the timer.

In some embodiments, the network device 120 may configure the timer to the terminal device 110. For example, the timer (denoted as DataInactivityTimer) may be configured as below.

It is to be understood that this is merely an example, and the timer may be any suitable timers existing or to be developed in future. In some alternative embodiments, the timer may be predefined.

FIG. 3C illustrates a schematic diagram 300C illustrating an example fallback of an LPWUS mode based on a timer according to embodiments of the present disclosure. As shown by reference sign 330 in FIG. 3C, upon reception of an LPWUS, the main radio 142 may warm up to perform a PDCCH monitoring based on a DRX cycle. DataInactivityTimer is started upon the main radio 142 is totally warmed up. As shown, no data related information is received during an active time window 331. Upon DataInactivityTimer expires, the terminal device 110 may enter an LPWUS mode (e.g., deactivate the main radio 142) to monitor an LPWUS. Although DataInactivityTimer is started upon the main radio 142 is totally warmed up in this example, DataInactivityTimer may be started upon reception of the LPWUS in some other examples.

As shown by reference sign 330’ in FIG. 3C, upon reception of an LPWUS, the main radio 142 may warm up to perform a PDCCH monitoring based on a DRX cycle. DataInactivityTimer is started upon the main radio 142 is totally warmed up. As shown, data related information is received at a timing F during an active time window 332. Accordingly, DataInactivityTimer is stopped. The terminal device 110 may continue to perform related operations in the connected state.

For illustration, an example procedure may be described as below.

Upon LPWUS detection, the UE shall:

1> monitor PDCCH on the Serving Cells when MR is activated;

1> start dataInactivityTimer if configured for LPWUS fallback purpose;

When dataInactivityTimer (for LPWUS) is configured, the UE in RRC_CONNECTED shall:

1> if any MAC entity receives a MAC SDU for DTCH logical channel, DCCH logical channel, or CCCH logical channel, or multicast MTCH logical channel; or

1> if any MAC entity transmits a MAC SDU for DTCH logical channel, or DCCH logical channel:

2> stop dataInactivityTimer.

1> if the dataInactivityTimer expires:

2> indicate the expiry of the dataInactivityTimer to upper layers (RRC) .

For illustration, another example procedure may be described as below.

Upon receiving the expiry of DataInactivityTimer from lower layers for LPWUS fallback purpose while in RRC_CONNECTED, the UE shall:

1> perform the actions upon entering/going to LPWUS mode (deactivate MR) to monitor LPWUS.

It is to be understood that the above example procedures are merely for illustration and are not intended for limitation.

In this way, based on a timer, a terminal device may determine that no any data related information arrives at a terminal device. Thus, the terminal device is unnecessary to stay in a connected state any longer, and may fall back to an LPWUS mode for power saving.

Embodiment 4

In this embodiment, with reference to FIG. 2, if the LPWUS is received, the terminal device 110 may transmit 244, to the network device 120, a notification (denoted as LPWUS_trigger notification herein) that the terminal device 110 enters the second mode due to reception of the LPWUS.

In some embodiments, the notification may be transmitted via uplink control information (UCI) . In some embodiments, the notification may be transmitted via a medium access control (MAC) control element (CE) . In some embodiments, the notification may be transmitted via an RRC signaling. It is to be understood that any other suitable ways are also feasible.

Based on the notification, the network device 120 may determine whether a false alarm issue happens. In some embodiments, if a false alarm issue happens, the network device 120 may transmit 245 an indication (denoted as LPWUS_fallback indication herein) of entering the first mode to the terminal device 110. Based on the indication, the terminal device 110 may determine that no data related information is received and enter the first mode to monitor an LPWUS.

In some embodiments, the indication may be transmitted via downlink control information (DCI) . In some embodiments, the indication may be transmitted via a MAC CE. In some embodiments, the indication may be transmitted via an RRC signaling (e.g., an RRC release message or an RRC reject message) . It is to be understood that any other suitable ways are also feasible.

In some embodiments, upon transmission of the notification, the terminal device 110 may start a timer (denoted as an LPWUS_notification timer herein) . In some embodiments, if the timer expires, the terminal device 110 may determine that no data related information is received and enter the first mode to monitor an LPWUS. In some embodiments, if data related information is received from the network device 120 (i.e., no false alarm issue happens) , the terminal device 110 may stop the timer. In some embodiments, if the indication of entering the first mode is received from the network device 120 (i.e., a false alarm issue happens) , the terminal device 110 may also stop the timer.

In some embodiments, the timer may be configured. In some alternative embodiments, the timer may be predefined.

For illustration, an example procedure may be described as below.

Upon LPWUS detection, UE shall:

1> monitor PDCCH on the Serving Cells when MR is activated;

1> if configured to provide LPWUS_trigger notification information:

2> start the LPWUS_notification timer;

2> initiate transmission of the LPWUS_trigger notification to the network (or submit the LPWUS_trigger notification message to lower layers for transmission) ; or

2> instruct the Multiplexing and Assembly procedure to generate the LPWUS_trigger notification MAC CE; or

2> the UE transmits a PUCCH for LPWUS_trigger notification.

1> if the LPWUS_notification timer expires:

2> perform the actions upon entering/going to LPWUS mode (deactivate MR) to monitor LPWUS;

1> if LPWUS_fallback indication is received from network via DCI/MAC CE/RRC:

2> stop the LPWUS_notification timer;

2> perform the actions upon entering/going to LPWUS mode (deactivate MR) to monitor LPWUS.

In this way, based on UE notification, a network device may determine whether a false alarm issue happens and then give a corresponding response to the notification. Based on the response from the network device, the terminal device may fall back to an LPWUS mode for power saving or continue to keep in the connected state for communication.

So far, fallback of an LPWUS mode from a PDCCH monitoring is described. With the process 200, an unnecessary PDCCH monitoring may be reduced and power saving at a terminal device may be achieved.

EXAMPLE IMPLEMENTATION OF FALLBACK FROM RA PROCEDURE

FIG. 4 illustrates a schematic diagram illustrating another process 400 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 400 will be described with reference to FIGs. 1A and 1B. The process 400 may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1A. It is to be understood that the steps and the order of the steps in FIG. 4 are merely for illustration, and not for limitation. For example, the order of the steps may be changed. Some of the steps may be omitted or any other suitable additional steps may be added.

As shown in FIG. 4, the network device 120 may transmit 410 a LPWUS configuration to the terminal device 110. In some embodiments, the network device 120 may transmit the LPWUS configuration in SI or in any other suitable ways. In some embodiments, the LPWUS configuration may indicate one or more occasions for LPWUS monitoring. In some embodiments, periodic monitoring may be configured for the LPWUS monitoring. In some embodiments, always-on monitoring may be configured for the LPWUS monitoring. It is to be understood that the LPWUS configuration may also comprise any other suitable information, and may also be transmitted in any other suitable ways.

Based on the LPWUS configuration, the terminal device 110 may perform 420 an LPWUS monitoring in a first mode. In the first mode, the main radio 142 of the terminal device 110 is turned off and the LPWUS receiver 141 of the terminal device 110 is turned on. In the context of the present disclosure, the first mode may also be referred to as an LPWUS mode or state, a sleep mode or state, or an ultra-deep sleep mode or state.

Continuing to refer to FIG. 4, the network device 120 may transmit 430 an LPWUS to the terminal device 110 in the LPWUS mode. Upon reception of the LPWUS, the terminal device 110 may initiate 440 an RA procedure in a second mode (e.g., activate the main radio 142) . The RA procedure indicates that the RA procedure is initiated due to reception of the LPWUS. In the second mode, the main radio 142 of the terminal device 110 is turned on and the LPWUS receiver 141 of the terminal device 110 is turned off. In some embodiments, the second mode may be an idle state or an inactive state. In some embodiments, the second mode may be a connected state.

Based on a reason of the RA procedure, the network device 120 may know whether a false alarm issue happens. In some embodiments where a false or unnecessary paging is done for the terminal device 110, the network device 120 may transmit a response indicating that the terminal device 110 enters the first mode. Alternatively, the network device 120 may transmit no response to the RA procedure.

Continuing to refer to FIG. 4, based on the response from the network device 120, the terminal device 110 may perform 450 an LPWUS monitoring in the first mode.

For illustration, some example embodiments will be described in connection with Embodiments 5 and 6 below.

Embodiment 5

In this embodiment, the terminal device 110 may initiate the RA procedure based on contention based random access (CBRA) . Upon reception of the LPWUS, the terminal device 110 may transmit a preamble to the network device 120 using a contention based preamble resource. The network device 120 may transmit, to the terminal device 110, a random access response (RAR) with a timing advance (TA) or an uplink grant or a temporary cell-radio network temporary identifier (TC-RNTI) .

In some embodiments, upon reception of the RAR, the terminal device 110 may transmit a request for establishing or resuming an RRC connection between the terminal device 110 and the network device 120. The request comprises a first indication that the request is transmitted due to reception of the LPWUS. In some embodiments, the first indication may be comprised in the request as a cause of the request.

In some embodiments, the terminal device 110 may transmit an RRC setup request message carrying the first indication as an establishment cause. For illustration, an example establishment cause may be described as below.

In this example, if the RRC setup request is initiated due to reception of an LPWUS, an establishment cause may indicate “lpwus-triggered” .

In some embodiments, the terminal device 110 may transmit an RRC resume request message carrying the first indication as a resume cause. For illustration, an example resume cause may be described as below.

In this example, if the RRC resume request is initiated due to reception of an LPWUS, a resume cause may indicate “lpwus-triggered” .

Based on the cause of “lpwus-triggered” , the network device 120 may determine whether a false alarm issue happens. If the false alarm issue happens, the network device 120 may transmit, to the terminal device 110, a response comprising a second indication of entering the first mode. In some embodiments, the network device 120 may transmit the response in an RRC release message. In some embodiments, the network device 120 may transmit the response in an RRC reject message.

Based on the second indication, the terminal device 110 may enter the first mode (e.g., deactivate the main radio 142) to monitor an LPWUS.

In some embodiments, the terminal device 110 may initiate an RA procedure whenever data is buffered in a logic channel of a common control channel (CCCH) . In some embodiments, if the network device 120 determines that no false alarm issue happens, the network device 120 may transmit, to the terminal device 110, an RRC setup message or an RRC resume message. In this way, the terminal device 110 may stay in a connected state.

For illustration, an example procedure may be described as below.

Upon LPWUS detection, UE may initiate the procedure of RRC connection establishment/resumption;

Step 1. UE selects the contention-based preamble to perform the Random Access Preamble transmission procedure.

Step 2. UE receives a downlink assignment (Msg2 -MAC RAR) on the PDCCH for the RA-RNTI.

Step 3. process the MAC RAR -Time Advance Command, Power Ramping, UL Grant, TC-RNTI.

After performing the above procedure, UE sends Msg3 –UL transmission by containing UL-CCCH SDU (i.e., RRCSetupRequest/RRCResumeRequest) with indication (cause) –LPWUS_trigger.

Once Msg3 is transmitted the MAC entity shall:

1> if notification of a reception of a PDCCH transmission of the SpCell is received from lower layers:

2> if the MAC PDU is successfully decoded:

3> stop ra-ContentionResolutionTimer;

3> if the MAC PDU contains a UE Contention Resolution Identity MAC CE; and

3> if the UE Contention Resolution Identity in the MAC CE matches the CCCH SDU transmitted in Msg3:

4> consider this Contention Resolution successful and finish the disassembly and demultiplexing of the MAC PDU.

For illustration, another example procedure may be described as below.

Upon reception of RRCRelease/RRCReject by the UE, the UE shall:

1> if the RRCRelease/RRCReject message including indication (cause) –LPWUS_fallback was received in response to an RRCSetupRequest or an RRCResumeRequest:

2> (may enter RRC_INACTIVE/IDLE firstly) enter LPWUS mode (within RRC_IDLE/INACTIVE) ;

2> deactivate the MR and monitor LPWUS.

In this way, a network device may reject a terminal device’s random access if the network device finds that this is a false alarm access.

Embodiment 6

In this embodiment, the terminal device 110 may initiate the RA procedure based on contention free random access (CFRA) . In some embodiments, the network device 120 may configure a resource (also referred to as an RA resource herein) dedicated for LPWUS to the terminal device 110. In other words, if the terminal device 110 is to initiate an RA procedure due to reception of an LPWUS, the terminal device 110 may initiate the RA procedure based on the RA resource dedicated for LPWUS. That is, the RA resource indicates that the RA procedure is initiated due to reception of the LPWUS.

For illustration, an example configuration of the RA resource may be described as below.

In this example, an information element (IE) “RACH-ConfigDedicatedForLpwus” indicates the RA resource dedicated for LPWUS.

In some embodiments, upon reception of the LPWUS, the terminal device 110 may transmit a preamble to the network device 120 using the RA resource. Based on the RA resource, the network device 120 may know that the RA procedure is initiated due to reception of the LPWUS. The network device 120 may determine whether a false alarm issue happens and then determine a response to the RA procedure.

In some embodiments, if the false alarm issue happens (e.g., a false or unnecessary paging is done for the terminal device 110) , the network device 120 may not transmit any response to the terminal device 110. For example, the network device 120 may not transmit an RAR to the terminal device 110. In some embodiments, if no false alarm issue happens (e.g., no false or unnecessary paging is done for the terminal device 110) , the network device 120 may transmit, to the terminal device 110 within an RAR window, an RAR comprising an index of the preamble. In some embodiments, if no false alarm issue happens (e.g., no false or unnecessary paging is done for the terminal device 110) , the network device 120 may transmit, to the terminal device 110 within an RAR window, a PDCCH transmission addressed to a cell-radio network temporary identifier (C-RNTI) specific to the terminal device 110.

In some embodiments, upon transmission of the preamble, the terminal device 110 may start an RAR window and monitor a response from the network device 120. In some embodiments, the terminal device 110 may monitor PDCCH for MAC RAR based on a random access-radio network temporary identifier (RA-RNTI) to check whether there is a preamble index within MAC RAR matching with a preamble index that the terminal device 110 selected. In some embodiments, if an RAR is received within the RAR window and a preamble index comprised in the RAR mismatches with an index of the preamble, the terminal device 110 may determine that no response is successfully received from the network device 120. In some embodiments, if no RAR is received within the RAR window, the terminal device 110 may determine that no response is successfully received from the network device 120.

In some embodiments, the terminal device 110 may monitor PDCCH for MAC RAR based on a C-RNTI specific to the terminal device 110 to check whether there is a PDCCH that is addressed to the C-RNTI. In some embodiments, the network device 120 may provide the C-RNTI to the terminal device 110 and the terminal device 110 may store the C-RNTI during the LPWUS mode. In some embodiments, if no PDCCH addressed to the C-RNTI specific to the terminal device 110 is received within the RAR window, the terminal device 110 may determine that no response is successfully received from the network device 120.

In some embodiments, if no response is successfully received from the network device 120 within the RAR window, the terminal device 110 may enter the first mode (e.g., deactivate the main radio 142) to monitor an LPWUS. In some embodiments, if an RAR comprising an index of the preamble or a PDCCH transmission addressed to a C-RNTI specific to the terminal device 110 is received, the terminal device 110 may stay in a connected state.

For illustration, an example procedure for RA-RNTI may be described as below. Once the Random Access Preamble is transmitted (for LPWUS) and regardless of the possible occurrence of a measurement gap, the MAC entity shall:

1> start the ra-ResponseWindow configured in RACH-ConfignDedicatedForLpwus at the first PDCCH occasion from the end of the Random Access Preamble transmission.

1> monitor the PDCCH of the serving cell for Random Access Response (s) identified by the RA-RNTI while the ra-ResponseWindow is running.

1> if a downlink assignment has been received on the PDCCH for the RA-RNTI and the received TB is successfully decoded:

2> if the Random Access Response contains a MAC subPDU with Random Access Preamble identifier corresponding to the transmitted PREAMBLE_INDEX:

3> consider this Random Access Response reception successful.

2> if the Random Access Response reception is considered successful:

3> if the random access procedure was initiated for LPWUS triggered notification (i.e., enter normal/activated RRC_CONNECTED due to LPWUS reception) :

2> acknowledge the LPWUS reception and keep staying in RRC_CONNCTED.

1> if ra-ResponseWindow configured in RACH-ConfignDedicatedForLpwus expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received:

2> consider the Random Access Response reception not successful;

2> if the random access procedure was initiated for LPWUS triggered notification:

2> enter LPWUS mode (deactivate the MR) to monitor LPWUS.

For illustration, an example procedure for C-RNTI may be described as below.

Once the Random Access Preamble is transmitted and regardless of the possible occurrence of a measurement gap, the MAC entity shall:

1> if the contention-free Random Access Preamble for LPWUS triggered notification was transmitted by the MAC entity:

2> start the ra-ResponseWindow configured in RACH-ConfignDedicatedForLpwus at the first PDCCH occasion from the end of the Random Access Preamble transmission.

2> monitor for a PDCCH transmission identified by the C-RNTI while ra-ResponseWindow is running.

1> if notification of a reception of a PDCCH transmission is received from lower layers on the Serving Cell where the preamble was transmitted; and

1> if PDCCH transmission is addressed to the C-RNTI; and

1> if the contention-free Random Access Preamble for LPWUS was transmitted by the MAC entity:

2> consider the Random Access procedure successfully completed.

2> acknowledge the LPWUS reception and keep staying in RRC_CONNCTED.

1>if ra-ResponseWindow configured in RACH-ConfignDedicatedForLpwus expires and if a PDCCH transmission addressed to the C-RNTI has not been received on the Serving Cell where the preamble was transmitted;

2> consider the Random Access Response reception not successful;

3> enter LPWUS mode (deactivate the MR) to monitor LPWUS.

So far, fallback of an LPWUS mode from an RA procedure is described. With the process 400, unnecessary RA may be reduced and power saving at a terminal device may be achieved.

It is to be understood that operations in the processes 200 and 400 may be carried out separately or in any suitable combination.

EXAMPLE IMPLEMENTATION OF METHODS

Corresponding to the above processes, embodiments of the present disclosure provide methods of communication implemented at a terminal device and at a network device. These methods will be described below with reference to FIGs. 5 to 7.

FIG. 5 illustrates an example method 500 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 500 may be performed at the terminal device 110 as shown in FIG. 1A. For the purpose of discussion, in the following, the method 500 will be described with reference to FIG. 1A. It is to be understood that the method 500 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 510, the terminal device 110 receives, from the network device 120, an LPWUS in a first mode. In some embodiments, a main radio of the terminal device 110 is turned off and an LPWUS receiver of the terminal device 110 is turned on in the first mode.

At block 520, the terminal device 110 performs a PDCCH monitoring in a second mode. In some embodiments, the main radio of the terminal device 110 is turned on and the LPWUS receiver of the terminal device 110 is turned off in the second mode.

At block 530, the terminal device 110 determines whether data related information is received in the second mode. If no data related information is received in the second mode, the method 500 proceeds to block 540.

At block 540, the terminal device 110 performs an LPWUS monitoring in the first mode.

In some embodiments, the terminal device 110 may perform the PDCCH monitoring based on a DRX cycle. If no data related information is received within a predetermined number of active time windows of DRX cycles, the terminal device 110 may determine that no data related information is received.

In some embodiments where a DCP monitoring is configured, if DCP is received for a predetermined number of times and the DCP indicates that no timer for an active time window of the DRX cycle is started, the terminal device 110 may determine that no data related information is received. In some embodiments, if no DCP is received, the terminal device 110 may determine that no data related information is received.

In some embodiments where no data related information is received, the terminal device 110 may suspend or stop using the DRX cycle for the PDCCH monitoring. In some embodiments where no data related information is received, the terminal device 110 may enter the first mode to monitor the LPWUS.

In some embodiments, if the LPWUS is received or a main radio of the terminal device 110 is turned on, the terminal device 110 may start a timer. If the timer expires, the terminal device 110 may determine that no data related information is received. In some embodiments, if data related information is received in the second mode, the terminal device 110 may stop the timer.

In some embodiments, if the LPWUS is received, the terminal device 110 may transmit, to the network device 120, a notification that the terminal device 110 enters the second mode due to reception of the LPWUS. In some embodiments, if an indication of entering the first mode is received from the network device 120, the terminal device 110 may determine that no data related information is received. In some embodiments, if the notification is transmitted, the terminal device 110 may start a timer. In some embodiments, if the timer expires, the terminal device 110 may determine that no data related information is received. In some embodiments, if data related information or the indication is received from the network device 120, the terminal device 110 may stop the timer.

In some embodiments, the data related information may comprise at least one of the following: a PDCCH transmission; DCI; a downlink assignment; a MAC PDU; a TB; or a PDSCH transmission.

In some embodiments, if the terminal device 110 determines at block 530 that data related information is received, the terminal device 110 may keep in the second mode to perform related operations.

With the method 500, fallback of an LPWUS mode from a PDCCH monitoring may be achieved and unnecessary power consumption for PDCCH monitoring may be reduced.

FIG. 6 illustrates another example method 600 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 600 may be performed at the terminal device 110 as shown in FIG. 1A. For the purpose of discussion, in the following, the method 600 will be described with reference to FIG. 1A. It is to be understood that the method 600 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 610, the terminal device 110 receives an LPWUS from the network device 120 in a first mode. In some embodiments, a main radio of the terminal device 110 is turned off and an LPWUS receiver of the terminal device 110 is turned on in the first mode.

At block 620, the terminal device 110 initiates an RA procedure in a second mode, the RA procedure indicating that the RA procedure is initiated due to reception of the LPWUS. In some embodiments, the main radio of the terminal device 110 is turned on and the LPWUS receiver of the terminal device 110 is turned off in the second mode.

In some embodiments, the terminal device 110 may transmit, to the network device 120, a request for establishing or resuming an RRC connection between the terminal device 110 and the network device 120, the request comprising a first indication that the request is transmitted due to reception of the LPWUS. In some embodiments, the first indication may be comprised in the request as a cause of the request.

In some embodiments, the terminal device 110 may transmit a preamble to the network device 120 based on a resource, the resource indicating that the RA procedure is initiated due to reception of the LPWUS.

At block 630, the terminal device 110 performs an LPWUS monitoring in the first mode based on a response to the RA procedure from the network device 120.

In some embodiments, the terminal device 110 may receive, from the network device 120, the response comprising a second indication of entering the first mode, and perform the LPWUS monitoring in the first mode based on the second indication. In some embodiments, the response comprising the second indication may be carried in an RRC release message or an RRC reject message.

In some embodiments, if no response is successfully received from the network device within an RAR window, the terminal device 110 may perform the LPWUS monitoring in the first mode. In some embodiments, if an RAR is received within the RAR window and a preamble index comprised in the RAR mismatches with an index of the preamble, the terminal device 110 may determine that no response is successfully received from the network device 120. In some embodiments, if no RAR is received within the RAR window, the terminal device 110 may determine that no response is successfully received from the network device 120. In some embodiments, if no PDCCH transmission addressed to a C-RNTI specific to the terminal device 110 is received within the RAR window, the terminal device 110 may determine that no response is successfully received from the network device 120.

With the method 600, fallback of an LPWUS mode from RA may be achieved and unnecessary power consumption for RA may be reduced.

FIG. 7 illustrates an example method 700 of communication implemented at a network device in accordance with some embodiments of the present disclosure. For example, the method 700 may be performed at the network device 120 as shown in FIG. 1A. For the purpose of discussion, in the following, the method 700 will be described with reference to FIG. 1A. It is to be understood that the method 700 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 710, the network device 120 transmits an LPWUS to the terminal device 110 in a first mode.

At block 720, the network device 120 performs an RA procedure initiated by the terminal device 110 in a second mode. The RA procedure indicates that the RA procedure is initiated due to reception of the LPWUS.

In some embodiments, the network device 120 may receive, from the terminal device 110, a request for establishing or resuming an RRC connection between the terminal device 110 and the network device 120. The request may comprise a first indication that the request is transmitted due to reception of the LPWUS. In some embodiments, the first indication may be comprised in the request as a cause of the request.

In some embodiments, the network device 120 may receive a preamble from the terminal device on a resource, the resource indicating that the random access procedure is initiated due to reception of the LPWUS.

At block 730, the network device 120 determines a response to the RA procedure. In some embodiments, if a false or unnecessary paging is done for the terminal device 110, the network device 120 may transmit, to the terminal device 110, the response comprising a second indication of entering the first mode. In some embodiments, the response comprising the second indication may be carried in an RRC release message or an RRC reject message.

In some embodiments, if a false or unnecessary paging is done for the terminal device 110, the network device 120 may transmit no response to the RA procedure to the terminal device 110. In some embodiments, if no false or unnecessary paging is done for the terminal device 110, the network device 120 may transmit, to the terminal device 110 within an RAR window, an RAR comprising an index of the preamble or a PDCCH transmission addressed to a C-RNTI specific to the terminal device 110.

With the method 700, fallback of an LPWUS mode from an RA procedure may be achieved and unnecessary power consumption for RA may be reduced.

It is to be understood that operations of the methods 500 to 700 correspond to the processes described in connection with FIGs. 2 to 4, and thus other details are omitted here for conciseness.

EXAMPLE IMPLEMENTATION OF DEVICES

FIG. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 can be considered as a further example implementation of the terminal device 110 or the network device 120 as shown in FIG. 1A. Accordingly, the device 800 can be implemented at or as at least a part of the terminal device 110 or the network device 120.

As shown, the device 800 includes a processor 810, a memory 820 coupled to the processor 810, a suitable transceiver 840 coupled to the processor 810, and a communication interface coupled to the transceiver 840. The memory 810 stores at least a part of a program 830. The transceiver 840 may be for bidirectional communications or a unidirectional communication based on requirements. The transceiver 840 may include at least one of a transmitter 842 or a receiver 844. The transmitter 842 and the receiver 844 may be functional modules or physical entities. The transceiver 840 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 830 is assumed to include program instructions that, when executed by the associated processor 810, enable the device 800 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1A to 7. The embodiments herein may be implemented by computer software executable by the processor 810 of the device 800, or by hardware, or by a combination of software and hardware. The processor 810 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 810 and memory 820 may form processing means 850 adapted to implement various embodiments of the present disclosure.

The memory 820 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 820 is shown in the device 800, there may be several physically distinct memory modules in the device 800. The processor 810 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 800 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 some embodiments, a terminal device comprises a circuitry configured to: receive, from a network device, an LPWUS in a first mode; perform a PDCCH monitoring in a second mode; and in accordance with a determination that no data related information is received in the second mode, perform an LPWUS monitoring in the first mode.

In some embodiments, a terminal device comprises a circuitry configured to: receive, from a network device, an LPWUS in a first mode; initiate a random access procedure in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and perform an LPWUS monitoring in the first mode based on a response to the random access procedure from the network device.

In some embodiments, a network device comprises a circuitry configured to: transmit an LPWUS to a terminal device in a first mode; perform a random access procedure initiated by the terminal device in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and determine a response to the random access procedure.

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.

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

In one solution, a terminal device comprises a processor configured to cause the terminal device to: receive, from a network device, a low-power wake-up signal (LPWUS) in a first mode; perform a physical downlink control channel (PDCCH) monitoring in a second mode; and in accordance with a determination that no data related information is received in the second mode, perform an LPWUS monitoring in the first mode.

In some embodiments, the terminal device is caused to perform the PDCCH monitoring by performing the PDCCH monitoring based on a discontinuous reception (DRX) cycle, and the terminal device is further caused to: in accordance with a determination that no data related information is received within a predetermined number of active time windows of DRX cycles, determine that no data related information is received.

In some embodiments, the terminal device is caused to perform the PDCCH monitoring by performing the PDCCH monitoring based on a discontinuous reception (DRX) cycle, and the terminal device is further caused to: in accordance with a determination that downlink control information with cyclic redundancy check scrambled by power saving-radio network temporary identifier (DCP) is received for a predetermined number of times and the DCP indicates that no timer for an active time window of the DRX cycle is started, determine that no data related information is received; or in accordance with a determination that no DCP is received, determine that no data related information is received.

In some embodiments, the terminal device is further caused to at least one of the following: suspend or stop using the DRX cycle for the PDCCH monitoring; or enter the first mode.

In some embodiments, the terminal device is further caused to: in accordance with a determination that the LPWUS is received or a main radio of the terminal device is turned on, start a timer; and in accordance with a determination that the timer expires, determine that no data related information is received.

In some embodiments, the terminal device is further caused to: in accordance with a determination that data related information is received in the second mode, stop the timer.

In some embodiments, the terminal device is further caused to: in accordance with a determination that the LPWUS is received, transmit, to the network device, a notification that the terminal device enters the second mode due to reception of the LPWUS.

In some embodiments, the terminal device is further caused to at least one of the following: in accordance with a determination that an indication of entering the first mode is received from the network device, determine that no data related information is received; in accordance with a determination that the notification is transmitted, start a timer; in accordance with a determination that the timer expires, determine that no data related information is received; or in accordance with a determination that data related information or the indication is received from the network device, stop the timer.

In some embodiments, a main radio of the terminal device is turned off and an LPWUS receiver of the terminal device is turned on in the first mode, and the main radio of the terminal device is turned on and the LPWUS receiver of the terminal device is turned off in the second mode.

In some embodiments, the data related information comprises at least one of the following: a PDCCH transmission; downlink control information (DCI) ; a downlink assignment; a medium access control (MAC) protocol data unit (PDU) ; a transport block (TB) ; or a physical downlink shared channel (PDSCH) transmission.

In another solution, a terminal device comprises a processor configured to cause the terminal device to: receive, from a network device, a low-power wake-up signal (LPWUS) in a first mode; initiate a random access procedure in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and perform an LPWUS monitoring in the first mode based on a response to the random access procedure from the network device.

In some embodiments, the terminal device is caused to initiate the random access procedure by: transmitting, to the network device, a request for establishing or resuming a radio resource control (RRC) connection between the terminal device and the network device, the request comprising a first indication that the request is transmitted due to reception of the LPWUS.

In some embodiments, the first indication is comprised in the request as a cause of the request.

In some embodiments, the terminal device is caused to perform the LPWUS monitoring by: receiving, from the network device, the response comprising a second indication of entering the first mode; and performing the LPWUS monitoring in the first mode based on the second indication.

In some embodiments, the response comprising the second indication is carried in an RRC release message or an RRC reject message.

In some embodiments, the terminal device is caused to initiate the random access procedure by: transmitting a preamble to the network device based on a resource, the resource indicating that the random access procedure is initiated due to reception of the LPWUS.

In some embodiments, the terminal device is caused to perform the LPWUS monitoring by: in accordance with a determination that no response is successfully received from the network device within a random access response (RAR) window, performing the LPWUS monitoring in the first mode.

In some embodiments, the terminal device is further caused to at least one of the following: in accordance with a determination that an RAR is received within the RAR window and a preamble index comprised in the RAR mismatches with an index of the preamble, determine that no response is successfully received from the network device; in accordance with a determination that no RAR is received within the RAR window, determine that no response is successfully received from the network device; or in accordance with a determination that no physical downlink control channel transmission addressed to a cell-radio network temporary identifier (C-RNTI) specific to the terminal device is received within the RAR window, determine that no response is successfully received from the network device.

In another solution, a network device comprises a processor configured to cause the network device to: transmit, to a terminal device in a first mode, a low-power wake-up signal (LPWUS) ; perform a random access procedure initiated by the terminal device in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and determine a response to the random access procedure.

In some embodiments, the network device is caused to perform the random access procedure by: receiving, from the terminal device, a request for establishing or resuming a radio resource control (RRC) connection between the terminal device and the network device, the request comprising a first indication that the request is transmitted due to reception of the LPWUS.

In some embodiments, the network device is caused to determine the response to the random access procedure by: in accordance with a determination that a false or unnecessary paging is done for the terminal device, transmitting, to the terminal device, the response comprising a second indication of entering the first mode.

In some embodiments, the network device is caused to perform the random access procedure by: receiving a preamble from the terminal device on a resource, the resource indicating that the random access procedure is initiated due to reception of the LPWUS.

In some embodiments, the network device is caused to determine the response to the random access procedure by: in accordance with a determination that a false or unnecessary paging is done for the terminal device, transmitting no response to the random access procedure to the terminal device; or in accordance with a determination that no false or unnecessary paging is done for the terminal device, transmitting, to the terminal device within a random access response (RAR) window, an RAR comprising an index of the preamble or a physical downlink control channel transmission addressed to a cell-radio network temporary identifier (C-RNTI) specific to the terminal device.

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. 1A to 7. 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 terminal device, comprising:

a processor configured to cause the terminal device to:

receive, from a network device, a low-power wake-up signal (LPWUS) in a first mode;

perform a physical downlink control channel (PDCCH) monitoring in a second mode; and

in accordance with a determination that no data related information is received in the second mode, perform an LPWUS monitoring in the first mode.
The terminal device of claim 1, wherein the terminal device is caused to perform the PDCCH monitoring by performing the PDCCH monitoring based on a discontinuous reception (DRX) cycle, and wherein the terminal device is further caused to:

in accordance with a determination that no data related information is received within a predetermined number of active time windows of DRX cycles, determine that no data related information is received.
The terminal device of claim 1, wherein the terminal device is caused to perform the PDCCH monitoring by performing the PDCCH monitoring based on a discontinuous reception (DRX) cycle, and wherein the terminal device is further caused to:

in accordance with a determination that downlink control information with cyclic redundancy check scrambled by power saving-radio network temporary identifier (DCP) is received for a predetermined number of times and the DCP indicates that no timer for an active time window of the DRX cycle is started, determine that no data related information is received; or

in accordance with a determination that no DCP is received, determine that no data related information is received.
The terminal device of claim 2 or 3, wherein the terminal device is further caused to at least one of the following:

suspend or stop using the DRX cycle for the PDCCH monitoring; or

enter the first mode.
The terminal device of claim 1, wherein the terminal device is further caused to:

in accordance with a determination that the LPWUS is received or a main radio of the terminal device is turned on, start a timer; and

in accordance with a determination that the timer expires, determine that no data related information is received.
The terminal device of claim 5, wherein the terminal device is further caused to:

in accordance with a determination that data related information is received in the second mode, stop the timer.
The terminal device of claim 1, wherein the terminal device is further caused to:

in accordance with a determination that the LPWUS is received, transmit, to the network device, a notification that the terminal device enters the second mode due to reception of the LPWUS.
The terminal device of claim 7, wherein the terminal device is further caused to at least one of the following:

in accordance with a determination that an indication of entering the first mode is received from the network device, determine that no data related information is received;

in accordance with a determination that the notification is transmitted, start a timer;

in accordance with a determination that the timer expires, determine that no data related information is received; or

in accordance with a determination that data related information or the indication is received from the network device, stop the timer.
The terminal device of claim 1, wherein a main radio of the terminal device is turned off and an LPWUS receiver of the terminal device is turned on in the first mode, and

wherein the main radio of the terminal device is turned on and the LPWUS receiver of the terminal device is turned off in the second mode.
The terminal device of claim 1, wherein the data related information comprises at least one of the following:

a PDCCH transmission;

downlink control information (DCI) ;

a downlink assignment;

a medium access control (MAC) protocol data unit (PDU) ;

a transport block (TB) ; or

a physical downlink shared channel (PDSCH) transmission.
A terminal device, comprising:

a processor configured to cause the terminal device to:

receive, from a network device, a low-power wake-up signal (LPWUS) in a first mode;

initiate a random access procedure in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and

perform an LPWUS monitoring in the first mode based on a response to the random access procedure from the network device.
The terminal device of claim 11, wherein the terminal device is caused to initiate the random access procedure by:

transmitting, to the network device, a request for establishing or resuming a radio resource control (RRC) connection between the terminal device and the network device, the request comprising a first indication that the request is transmitted due to reception of the LPWUS.
The terminal device of claim 12, wherein the first indication is comprised in the request as a cause of the request.
The terminal device of claim 12, wherein the terminal device is caused to perform the LPWUS monitoring by:

receiving, from the network device, the response comprising a second indication of entering the first mode; and

performing the LPWUS monitoring in the first mode based on the second indication.
The terminal device of claim 14, wherein the response comprising the second indication is carried in an RRC release message or an RRC reject message.
The terminal device of claim 11, wherein the terminal device is caused to initiate the random access procedure by:

transmitting a preamble to the network device based on a resource, the resource indicating that the random access procedure is initiated due to reception of the LPWUS.
The terminal device of claim 16, wherein the terminal device is caused to perform the LPWUS monitoring by:

in accordance with a determination that no response is successfully received from the network device within a random access response (RAR) window, performing the LPWUS monitoring in the first mode.
The terminal device of claim 17, wherein the terminal device is further caused to at least one of the following:

in accordance with a determination that an RAR is received within the RAR window and a preamble index comprised in the RAR mismatches with an index of the preamble, determine that no response is successfully received from the network device;

in accordance with a determination that no RAR is received within the RAR window, determine that no response is successfully received from the network device; or

in accordance with a determination that no physical downlink control channel transmission addressed to a cell-radio network temporary identifier (C-RNTI) specific to the terminal device is received within the RAR window, determine that no response is successfully received from the network device.
The terminal device of claim 11, wherein a main radio of the terminal device is turned off and an LPWUS receiver of the terminal device is turned on in the first mode, and

wherein the main radio of the terminal device is turned on and the LPWUS receiver of the terminal device is turned off in the second mode.
A network device, comprising:

a processor configured to cause the network device to:

transmit, to a terminal device in a first mode, a low-power wake-up signal (LPWUS) ;

perform a random access procedure initiated by the terminal device in a second mode, the random access procedure indicating that the random access procedure is initiated due to reception of the LPWUS; and

determine a response to the random access procedure.