WO2023245437A1

WO2023245437A1 - Method, device and computer storage medium of communication

Info

Publication number: WO2023245437A1
Application number: PCT/CN2022/100195
Authority: WO
Inventors: Gang Wang
Original assignee: Nec Corporation
Priority date: 2022-06-21
Filing date: 2022-06-21
Publication date: 2023-12-28

Abstract

Embodiments of the present disclosure relate to methods, devices and computer readable media of communication. In the method, if a terminal device is allowed to receive a multicast service in an inactive state and DRX for the multicast service is configured, the terminal device determines whether a monitoring period is to be reduced. If the monitoring period is to be reduced, the terminal device changes the DRX to reduce the monitoring period. In this way, power saving may be achieved for multicast reception in an inactive state.

Description

METHOD, DEVICE AND COMPUTER STORAGE MEDIUM 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 multicast and broadcast service (MBS) .

BACKGROUND

To enable resource-efficient delivery of MBS, the third generation partnership project (3GPP) has developed new radio (NR) broadcast and multicast in Release 17. In Release 17, multicast is only specified for user equipment (UE) in a connected state, which may not fully fulfil requirements of some services (e.g., mission critical services) especially for cells with a large number of UEs. In addition, to always keep UEs in a connected state is not power efficient. It is therefore important to support multicast for UEs in an inactive state. However, solutions of managing multicast reception in an inactive state are still incomplete and need to be further developed.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage media of communication for managing multicast reception in an inactive state.

In a first aspect, there is provided a method of communication. The method comprises: in accordance with a determination that a terminal device is allowed to receive a multicast service in an inactive state and discontinuous reception for the multicast service is configured, determining, at the terminal device, whether a monitoring period is to be reduced; and in accordance with a determination that the monitoring period is to be reduced, changing the discontinuous reception to reduce the monitoring period.

In a second aspect, there is provided a method of communication. The method comprises: in accordance with a determination that a paging message is received while a terminal device is allowed to receive a multicast service in an inactive state, performing, at the terminal device, multicast reception in the inactive state based on a configuration stored for the multicast reception.

In a third aspect, there is provided a device of communication. The device of communication comprises a processor configured to cause the device to perform the method according to the first or second aspect of the present disclosure.

In a fourth 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 the first or second aspect 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. 1 illustrates an example communication network in which some embodiments of the present disclosure can be implemented;

FIG. 2A illustrates a schematic diagram of a unicast scenario in which some embodiments of the present disclosure can be implemented;

FIG. 2B illustrates a schematic diagram of a multicast scenario in which some embodiments of the present disclosure can be implemented;

FIG. 2C illustrates a schematic diagram of an example scenario of multicast reception in a connected state and in an inactive state;

FIG. 3 illustrates a schematic diagram illustrating a process of communication for managing multicast reception in an inactive state according to embodiments of the present disclosure;

FIG. 4A illustrates a schematic diagram illustrating an example of a WUS according to embodiments of the present disclosure;

FIG. 4B illustrates a schematic diagram illustrating an example of multicast reception based on a WUS according to embodiments of the present disclosure;

FIG. 5A illustrates a schematic diagram illustrating an example of multicast reception based on a timer and dual multicast configurations according to embodiments of the present disclosure;

FIG. 5B illustrates a schematic diagram illustrating an example of multicast reception based on a counter and dual multicast configurations according to embodiments of the present disclosure;

FIG. 5C illustrates a schematic diagram illustrating an example of multicast reception based on a timer and an extend factor according to embodiments of the present disclosure;

FIG. 5D illustrates a schematic diagram illustrating an example of multicast reception based on a counter and an extend factor according to embodiments of the present disclosure;

FIG. 6 illustrates a schematic diagram illustrating another process of communication for managing a multicast reception in an inactive state according to embodiments of the present disclosure;

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

FIG. 8 illustrates another example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure; and

FIG. 9 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 incorporated one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

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’a re 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 “MBS” may be interchangeably used with “multicast” , “multicast service” , “multicast transmission” or “multicast data” . The term “multicast reception” may be interchangeably used with “MBS reception” . The term “a connected state” may be interchangeably used with “a RRC_CONNECTED state” , the term “an idle state” may be interchangeably used with “a RRC_IDLE state” , and the term “an inactive state” may be interchangeably used with “a RRC_INACTIVE state” .

Currently, a network may configure independent multicast discontinuous reception (DRX) to a terminal device. However, when a terminal device receives a multicast service in an inactive state, the terminal device cannot acknowledge whether the multicast service is temporarily stopped or not. Thus the terminal device will always monitor a multicast session, which may cause unnecessary power consumption.

In view of this, embodiments of the present disclosure provide a solution for managing multicast reception in an inactive state. In the solution, if a terminal device is allowed to receive a multicast service in an inactive state and DRX for the multicast service is configured, the terminal device determines whether a monitoring period is to be reduced. If the monitoring period is to be reduced, the terminal device changes the DRX to reduce the monitoring period. In this way, power saving may be achieved for multicast reception in an inactive state.

On the other hand, if a terminal device receives a multicast paging in an inactive state, the terminal device generally needs to initiate a random access procedure to go back to a connected state, which is inefficient.

In view of this, embodiments of the present disclosure provide another solution for managing multicast reception in an inactive state. In the solution, if a paging message is received while a terminal device is allowed to receive a multicast service in an inactive state, the terminal device performs multicast reception in the inactive state based on a configuration stored for the multicast reception. In this way, efficient multicast reception in an inactive state may be achieved.

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

EXAMPLE OF COMMUNICATION NETWORK

FIG. 1 illustrates a schematic diagram of an example communication network 100 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1, the communication network 100 may include a terminal device 110 and a network device 120. In some embodiments, 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.

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

As shown in FIG. 1, the terminal device 110 may communicate with the network devices 120 and 130 via a channel such as a wireless communication channel. The communications in the communication network 100 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.

In some embodiments where the terminal device 110 is served by the network device 120, the terminal device 110 may receive a unicast service from the network device 120. FIG. 2A illustrates a schematic diagram of a unicast scenario 200A in which some embodiments of the present disclosure can be implemented. As shown in FIG. 2A, a base station 210 may transmit downlink control information (DCI) on a physical downlink control channel (PDCCH) 201 with a cell-radio network temporary identifier (C-RNTI) for UE1. In this way, UE1 may be scheduled to receive data (for example, video stream) on a physical downlink shared channel (PDSCH) 202 in unicast. Similarly, the base station 210 may transmit DCI on a PDCCH 203 with a C-RNTI for UE2 to schedule UE2 to receive the data on a PDSCH 204 in unicast. The base station 210 may transmit DCI on a PDCCH 205 with a C-RNTI for UE3 to schedule UE3 to receive the data on a PDSCH 206 in unicast.

In some embodiments where the terminal device 110 is served by the network device 120, the terminal device 110 may receive a multicast service from the network device 120. FIG. 2B illustrates a schematic diagram of a multicast scenario 200B in which some embodiments of the present disclosure can be implemented. As shown in FIG. 2B, the base station 210 may transmit DCI on a PDCCH 207 with a group-radio network temporary identifier (G-RNTI) for a set of UEs 220. In this way, the set of UEs 220 may be scheduled to receive the data on a PDSCH 208 in multicast, i.e., to receive the data simultaneously.

That is, for multicast communication service, the same service and the same specific content data are provided simultaneously to a dedicated set of UEs (i.e., not all UEs in the multicast service area are authorized to receive the data) . A multicast communication service is delivered to the UEs using a multicast session. A UE can receive a multicast communication service in a connected state with mechanisms such as point-to-point (PTP) and/or PTM delivery.

In some embodiments, the terminal device 110 may receive data of MBS multicast session only in a connected state. If the terminal device 110 which joined a multicast session is in a connected state and when the multicast session starts, the network device 120 may transmit a radio resource control (RRC) reconfiguration message with relevant MBS configuration (also referred to as a multicast configuration) for the multicast session to the terminal device 110. In this case, there is no need for separate session activation notification for the terminal device 110.

In some embodiments, when there is no data to be sent to the terminal device 110 for a multicast session, the network device 120 may cause the terminal device 110 to enter an inactive state. In some embodiments, when a multicast session has been activated by a core network (CN) or the network device 120 has multicast session data to delivery, the network device 120 may use a group notification mechanism (i.e., multicast paging) to notify the terminal device 110 in an inactive state.

It has been proposed that a terminal device may enter an inactive state to continue receiving multicast service. A network device may configure independent multicast DRX to a terminal device, which means that unicast DRX and multicast DRX run separately. However, there is no wake-up signal (WUS) for multicast DRX. For a terminal device in an inactive state, there is no dedicated PUCCH resource and DL-DCCH configuration. That is, a network cannot send a dedicated signal to the terminal device, and does not know situation of the terminal device except from paging information.

FIG. 2C illustrates a schematic diagram of an example scenario 200C of multicast reception in a connected state and in an inactive state. As shown in an upper portion of FIG. 2C, a terminal device may receive multicast data in a connected state. If there is no multicast data for a period of time since timing T1, the terminal device may enter an inactive state at timing T2 for power saving. In this case, the terminal device does not need to monitor multicast data any more. If a paging message is received, the terminal device may enter a connected state to receive multicast data at timing T3.

As shown in a lower portion of FIG. 2C, a terminal device may receive multicast data in an inactive state. If there is no multicast data for a period of time since timing T4, the terminal device will always monitor multicast data with no indication from a network device. This will cause unnecessary power consumption.

Embodiments of the present disclosure provide solutions for managing multicast reception in an inactive state so as to overcome the above and other potential issues. The detailed description will be made with reference to FIGs. 3 to 5D below.

EXAMPLE IMPLEMENTATION OF MANAGEMENT OF MULTICAST RECEPTION

FIG. 3 illustrates a schematic diagram illustrating a process 300 of communication for managing multicast reception in an inactive state according to embodiments of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to FIG. 1. The process 300 may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1. It is to be understood that the steps and the order of the steps in FIG. 3 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. 3, the network device 120 may transmit 310 a configuration of multicast DRX to the terminal device 110. In some embodiments, the configuration may comprise at least one of the following DRX parameters: an on-duration timer, an inactivity timer, a retransmission timer, a start offset for a long cycle, or a slot offset. It is to be understood that these merely are examples, and the configuration may comprise any suitable DRX parameters.

In some embodiments, the network device 120 may transmit the configuration via a radio resource control (RRC) message, for example, a RRCReconfiguration message or a RRCRelease message. It is to be understood that any other suitable ways are also feasible.

The terminal device 110 may determine 320 whether the terminal device 110 is to receive a multicast service in an inactive state. If the terminal device 110 is to receive a multicast service in an inactive state, the terminal device 110 may determine 330 whether a monitoring period is to be reduced.

In some embodiments, the terminal device 110 may determine whether a monitoring period is to be reduced based on an indication from the network device 120. In some embodiments, the terminal device 110 may determine whether a monitoring period is to be reduced based on a timer. In some embodiments, the terminal device 110 may determine whether a monitoring period is to be reduced based on a counter.

If the monitoring period is to be reduced, the terminal device 110 may change 340 the multicast DRX to reduce the monitoring period. In this way, further power saving may be achieved for multicast reception in an inactive state.

For illustration, some example embodiments will be described in connection with Embodiments 1 to 4 below. In the context of the present disclosure, the term “multicast DRX” may be interchangeably used with “DRX” , “DRX for a multicast service” or “DRX for multicast” , and the terminal “WUS” may be interchangeably used with “multicast WUS” or “WUS for multicast” .

Embodiment 1

In this embodiment, an indication from a network is introduced for multicast DRX monitoring. In some embodiments, the indication may be used to provide a wake-up indication for on-duration of multicast DRX. In some embodiments, the indication may be used to inform a terminal device in an inactive state that a multicast session is stopped or modified. For convenience, the following description is given by taking a WUS as an example of the indication. It is to be understood that the indication may also adopt any other suitable forms.

In some embodiments, the configuration of multicast DRX may comprise a configuration (for convenience, also referred to as a WUS configuration herein) for a WUS for multicast DRX monitoring.

In some embodiments, the WUS configuration may comprise a radio network temporary identifier (RNTI) for reception of the WUS. In some embodiments, the RNTI may be newly defined for reception of the WUS. The RNTI may be used for scrambling cyclic redundancy check (CRC) of DCI carrying the WUS. In some embodiments, if the RNTI is not configured by a network, the RNTI may be a fixed or predefined value, e.g., 0xFFF3-0xFFFC. In some embodiments, the RNTI may be a configured G-RNTI for the multicast service.

In some embodiments, the WUS configuration may comprise an exception indication indicating whether an on-duration timer for multicast DRX is started if the WUS is not received. In some embodiments, the WUS configuration may comprise both the RNTI and the exception indication.

In some embodiments, if the terminal device 110 is allowed to receive the multicast service in the inactive state and the WUS is configured for multicast DRX monitoring, the terminal device 110 may store the WUS configuration upon entering an inactive state.

In some embodiments, the WUS may comprise an indication of stopping a multicast session. In some embodiments, the WUS may comprise an indication of modifying a multicast configuration. In some embodiments, the WUS may comprise an indication of starting the on-duration timer for multicast DRX.

It is to be understood that the WUS may comprise any combination of the above information and any other suitable information. FIG. 4A illustrates a schematic diagram 400A illustrating an example of a WUS according to embodiments of the present disclosure. As shown in FIG. 4A, a bit 421 may indicate whether to stop a multicast session, a bit 422 may indicate whether to modify a multicast configuration, and a bit 423 may indicate whether to start the on-duration timer for multicast DRX. It is to be understood that FIG. 4A is merely an example, and any other suitable forms are also feasible.

The terminal device 110 may monitor the WUS before an on-duration timer for multicast DRX starts. In some embodiments, if the WUS is received and the WUS comprises the indication of stopping a multicast session, the terminal device 110 may stop a monitoring of the multicast service in multicast DRX.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTVE and Mcast WUS is configured for Mcast DRX monitoring:

2> store the Mcast WUS related configuration in RRC_INACTVE;

2> monitors Mcast WUS before the corresponding drx-onDurationTimerPTM starts;

3> if the session stop indication is received from Mcast WUS:

4> stop monitoring Mcast session corresponding to this DRX; (i.e. disabled) ;

3> if the modification indication is received from Mcast WUS:

4> initiates RRC resume procedure to receive the modified configuration when entering RRC_CONNECTED;

3> if the wake up indication is received from Mcast WUS and indicates to start corresponding drx-onDurationTimerPTM, or

3> if exception indication is configured with value true and Mcast WUS has not been received from lower layer:

4> start drx-onDurationTimerPTM after drx-SlotOffsetPTM from the beginning of the subframe. (i.e. UE will monitor Mcast session within drx-onDurationTimerPTM) .

For illustration, an example will be described in connection with FIG. 4B. FIG. 4B illustrates a schematic diagram 400B illustrating an example of multicast reception based on a WUS according to embodiments of the present disclosure. As shown by reference sign 430 of FIG. 4B, UE1 may receive a WUS 431 comprising an indication of starting the on-duration timer, and then UE1 may normally monitor a multicast session on an on-duration 432. Next, UE1 may receive a WUS 433 comprising an indication of stopping a multicast session. Then UE1 may disable subsequent multicast reception, for example, may stop monitoring a multicast session on on-

durations

434, 435 and subsequent on-durations.

In some embodiments, if the WUS is received and the WUS comprises the indication of modifying the multicast configuration, the terminal device 110 may initiate a RRC resume procedure to receive a modified multicast configuration in a connected state. An example will be described in connection with FIG. 4B.

As shown by reference sign 440 of FIG. 4B, UE2 may receive a WUS 441 comprising an indication of starting the on-duration timer, and then UE2 may normally monitor a multicast session on an on-duration 442. Next, UE2 may receive a WUS 443 comprising an indication of modifying a multicast configuration. Then UE2 may initiate a RRC resume procedure to enter a connected state and receive modified multicast configuration in the connected state.

In some embodiments, if the WUS is received and the WUS comprises the indication of starting the on-duration timer for multicast DRX, the terminal device 110 may start the on-duration timer for multicast DRX. An example will be described in connection with FIG. 4B.

As shown by reference sign 450 of FIG. 4B, UE3 may receive a WUS 451 comprising an indication of starting the on-duration timer (e.g., wake up indication = 1) , and then UE3 may monitor a multicast session on an on-duration 452. UE3 may receive a WUS 453 comprising an indication of not starting the on-duration timer (e.g., wake up indication = 0) , and then UE3 may stop monitoring a multicast session on an on-duration 454. UE3 may receive a WUS 455 comprising an indication of starting the on-duration timer (e.g., wake up indication = 1) , and then UE3 may monitor a multicast session on an on-duration 456.

In some embodiments, if the WUS is not received but an exception indication is configured with a true value (for convenience, also referred to as a first value herein) , the terminal device 110 may also start the on-duration timer for multicast DRX. An example will be described in connection with FIG. 4B.

As shown by reference sign 460 of FIG. 4B, in an example, UE4 may not receive a WUS at timing t1. As an exception indication is configured with true, UE4 may start an on-duration timer and monitor a multicast session on an on-duration 461. In another example, an exception indication may be not configured. If UE4 does not receive a WUS at timing t2, UE4 may not start an on-duration timer, i.e., stop monitoring a multicast session on an on-duration 462.

In this way, a terminal device in an inactive state may know multicast situation based on WUS monitoring and achieve efficient management for multicast reception to reduce power consumption.

Embodiment 2

In this embodiment, system information (e.g., a system information block (SIB) ) may be used for management of multicast reception.

In some embodiments, system information may comprise an indication of stopping a multicast session for a set of multicast services. The indication may comprise a temporary mobile group identity (TMGI) list associated with the set of multicast services. In these embodiments, if the terminal device 110 receives, from the network device 120, the system information comprising the indication of stopping a multicast session and the TMGI list in the indication comprises a TMGI of the current multicast service, the terminal device 110 may stop monitoring the current multicast service.

In some embodiments, system information may comprise an indication of modifying a multicast configuration for a set of multicast services. In some embodiments, the indication may comprise a TMGI list associated with the set of multicast services. In these embodiments, if the terminal device 110 receives, from the network device 120, the system information comprising the indication of modifying a multicast configuration and the TMGI list in the indication comprises a TMGI of the current multicast service, the terminal device 110 may initiate a RRC resume procedure to receive a modified multicast configuration in a connected state.

In this way, a terminal device in an inactive state may know multicast situation based on system information and achieve efficient management for multicast reception to reduce power consumption.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTVE:

2> monitor the PDCCH for this G-RNTI or G-CS-RNTI in RRC_INACTVE;

2> if short message indicating system information changed is received:

3> if in SIBx, multicast session stop which includes the TMGI which UE is interested is indicated:

4> stop monitoring Mcast session; (i.e. disabled) ;

3> if in SIBx, multicast session modification which includes the TMGI which UE is interested is indicated:

4> initiates RRC resume procedure to receive the modified configuration when entering RRC_CONNECTED.

Embodiment 3

In this embodiment, DCI may be used for management of multicast reception.

In some embodiments, the network device 120 may configure, to the terminal device 110 via a RRC message, new DCI for multicast monitoring. In some embodiments, the configuration of the new DCI may comprise new RNTI or configured G-RNTI. In some embodiments, the configuration of the new DCI may comprise a search space and a control resource set (CORESET) configuration. It is to be understood that the configuration of the new DCI may also comprise any combination of the above information and any other suitable information.

In some embodiments, if the terminal device 110 is allowed to receive the multicast service in the inactive state and DCI is configured for multicast DRX monitoring, the terminal device 110 may store the current multicast configuration upon entering the inactive state.

In some embodiments, the network device 120 may transmit DCI to the terminal device 110 for management of multicast reception in an inactive state. In some embodiments, the DCI may comprise an indication of stopping a multicast session for a set of multicast services. The indication may comprise a TMGI list associated with the set of multicast services. In some embodiments, DCI may comprise an indication of modifying a multicast configuration for a set of multicast services. The indication may comprise a TMGI list associated with the set of multicast services.

In some embodiments, if the terminal device 110 receives, from the network device 120, the DCI comprising the indication of stopping a multicast session and the TMGI list in the indication comprises a TMGI of the current multicast service, the terminal device 110 may stop monitoring the current multicast service.

In some embodiments, if the terminal device 110 receives, from the network device 120, the DCI comprising the indication of modifying a multicast configuration and the TMGI list in the indication comprises a TMGI of the current multicast service, the terminal device 110 may initiate a RRC resume procedure to receive a modified multicast configuration in a connected state.

In this way, a terminal device in an inactive state may know multicast situation based on DCI and achieve efficient management for multicast reception to reduce power consumption.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTVE and “new DCI” is configured for Mcast monitoring:

2> store the Mcast WUS related configuration in RRC_INACTVE;

2> monitor this new DCI based on the configuration;

3> if the session stop indication is received from the new DCI corresponding to the TMGI that UE is interested:

4> stop monitoring Mcast session; (i.e. disabled)

3> if the modification indication is received from the new DCI corresponding to the TMGI that UE is interested :

Embodiment 4

In this embodiment, dual DRX configurations may be introduced for management of multicast reception.

In some embodiments, the configuration of multicast DRX may comprise a first configuration and a second configuration for multicast DRX, the second configuration having a reduced monitoring period for multicast DRX than the first configuration. In some embodiments, the second configuration may have common DRX parameters to the first configuration except a parameter of an on-duration timer and a parameter of a long cycle. For example, the second configuration may be provided as below.

1. Timer based Solution

In some embodiments, the network device 120 may configure a timer (for convenience, also referred to as a multicast timer herein) that is used to determine when the terminal device 110 needs to use the second configuration to monitor a multicast session in an inactive state.

In some embodiments, the terminal device 110 may start the timer if the second configuration is configured. If the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced and apply the second configuration for multicast DRX.

In some embodiments, if the second configuration is applied for multicast DRX, the terminal device 110 may disable the timer. In some embodiments, if a downlink control transmission (e.g., PDCCH) indicates downlink multicast transmission and the first configuration is applied for multicast DRX, the terminal device 110 may restart the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for multicast DRX, the terminal device 110 may apply the first configuration for multicast DRX and start the timer.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTVE and Mcast DRX is configured:

2> if [ (SFN × 10) + subframe number] modulo (drx-LongCycle-PTM) =drx-StartOffset-PTM:

3> start drx-onDurationTimerPTM after drx-SlotOffsetPTM from the beginning of the subframe;

2> if the second Mcast DRX is configured:

3> start the Mcast timer;

2> if the MAC entity is in Active Time for this G-RNTI or G-CS-RNTI:

3> monitor the PDCCH for this G-RNTI or G-CS-RNTI;

3> if the PDCCH indicates a DL multicast transmission:

4> if the first Mcast DRX is used:

5> restart the Mcast timer;

4> if the second Mcast DRX is used:

5> use the first Mcast DRX parameters (i.e. the second Mcast DRX is disabled) ;

5> start the Mcast timer;

2> if the Mcast timer expires:

3> use the second Mcast DRX parameters for this DRX;

2> if the second Mcast DRX is used, and [ (SFN × 10) + subframe number] modulo (drx-LongCycle-PTM1) = drx-StartOffset-PTM:

4> start drx-onDurationTimerPTM1 after drx-SlotOffsetPTM from the beginning of the subframe;

4> disable the Mcast timer.

For illustration, an example will be described in connection with FIG. 5A. FIG. 5A illustrates a schematic diagram 500A illustrating an example of multicast reception based on a timer and dual multicast configurations according to embodiments of the present disclosure. In this example, it is assumed that a multicast timer is 50ms, an on-duration timer for the first configuration is 8ms, a long cycle timer for the first configuration is 20ms, an on-duration timer for the second configuration is 4ms, and a long cycle timer for the second configuration is 40ms.

As shown in FIG. 5A, the terminal device 110 may enter an inactive state at timing t3. Then the terminal device 110 may start the multicast timer of 50ms. Meanwhile, the terminal device 110 may apply the long cycle timer of 20ms and the on-duration timer of 8ms for multicast DRX. When multicast data is received during an on-duration 501, the terminal device 110 may restart the multicast timer of 50ms. As no multicast data is received then, the multicast timer expires at timing t4. Then the second configuration may be applied, i.e., the terminal device 110 may apply the long cycle timer of 40ms and the on-duration timer of 4ms for multicast DRX.

It is to be understood that FIG. 5A is merely an example, and does not limit the present disclosure.

2. Counter based Solution

In some embodiments, the network device 120 may configure a counter (e.g., maximum count) that is used to determine when the terminal device 110 needs to use the second configuration to monitor a multicast session in an inactive state.

In some embodiments, if the first configuration is applied for multicast DRX and there is no downlink control transmission indicating downlink multicast transmission in one cycle of multicast DRX, the terminal device 110 may increment a value of a counter. If the value of the counter is above a predetermined value (e.g., greater than or equal to the predetermined value) , the terminal device 110 may determine that the monitoring period is to be reduced and apply the second configuration for the multicast DRX. In some embodiments, the predetermined value may be the configured maximum count.

In some embodiments, if the second configuration is applied for multicast DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for multicast DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for multicast DRX, the terminal device 110 may apply the first configuration for multicast DRX.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTIVE and Mcast DRX is configured:

2> if the MAC entity is in Active Time for this G-RNTI or G-CS-RNTI:

3> monitor the PDCCH for this G-RNTI or G-CS-RNTI;

3> if the PDCCH indicates a DL multicast transmission:

4> if the first Mcast DRX is used:

5> reset the count;

4> if the second Mcast DRX is used:

5> use the first Mcast DRX parameters (i.e. the second Mcast DRX is disabled) ;

3> else if there is no any PDCCH indication for a DL multicast transmission in one DRX cycle and the first Mcast DRX is used:

4> increment the count by 1;

2> if the count ≥ max_count:

3> use the second Mcast DRX parameters for this DRX;

3> reset the count;

4> start drx-onDurationTimerPTM1 after drx-SlotOffsetPTM from the beginning of the subframe.

For illustration, an example will be described in connection with FIG. 5B. FIG. 5B illustrates a schematic diagram 500B illustrating an example of multicast reception based on a counter and dual multicast configurations according to embodiments of the present disclosure. In this example, it is assumed that a maximum count is 2, an on-duration timer for the first configuration is 8ms, a long cycle timer for the first configuration is 20ms, an on-duration timer for the second configuration is 4ms, and a long cycle timer for the second configuration is 40ms.

As shown in FIG. 5B, the terminal device 110 may enter an inactive state at timing t5. Then the terminal device 110 may apply the long cycle timer of 20ms and the on-duration timer of 8ms. As no multicast data is received during an on-duration 511, the terminal device 110 may increment the counter, e.g., count =1. When multicast data is received during an on-duration 512, the terminal device 110 may reset the counter, e.g., count=0. As no multicast data is received during an on-duration 513, the terminal device 110 may increment the counter, e.g., count =1. As no multicast data is received during an on-duration 514, the terminal device 110 may increment the counter, e.g., count =2 (i.e., the maximum count) . Then the second configuration may be applied at timing t6, i.e., the terminal device 110 may apply the long cycle timer of 40ms and the on-duration timer of 4ms.

It is to be understood that FIG. 5B is merely an example, and does not limit the present disclosure.

In this way, a terminal device in an inactive state may achieve efficient management for multicast reception to reduce power consumption.

Embodiment 5

In this embodiment, an extend factor for extending a cycle of multicast DRX may be introduced for management of multicast reception.

In some embodiments, the configuration of multicast DRX may comprise an extend factor. The extend factor may be used to extend multicast DRX cycle when the terminal device 110 receives a multicast session in an inactive state.

1. Timer based Solution

In some embodiments, the network device 120 may configure a timer (also referred to as a multicast timer) that is used to determine when the terminal device 110 needs to use the extend factor to extend multicast DRX cycle in the inactive state.

In some embodiments, the terminal device 110 may start the timer if the extend factor is configured. If the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced and apply the extend factor to extend the multicast DRX cycle. For example, the terminal device 110 may obtain an extended DRX cycle by multiplexing a configured DRX cycle with the extend factor.

In some embodiments, if the extend factor is applied for multicast DRX, the terminal device 110 may disable the timer. In some embodiments, if a downlink control transmission (e.g., PDCCH) indicates downlink multicast transmission and the extend factor is not applied for multicast DRX, the terminal device 110 may restart the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for multicast DRX, the terminal device 110 may disable the extend factor for multicast DRX and start the timer.

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

Upon entering RRC_INACTIVE, the UE shall:

2> if the extend factor is configured:

3> start the Mcast timer;

2> if the MAC entity is in Active Time for this G-RNTI or G-CS-RNTI:

3> monitor the PDCCH for this G-RNTI or G-CS-RNTI;

3> if the PDCCH indicates a DL multicast transmission:

4> if the Mcast DRX cycle has already been extended by extend factor:

5> use the legacy Mcast DRX cycle (i.e. extend factor is disabled) ;

5> start the Mcast timer;

4> else:

5> restart the Mcast timer;

2> if the Mcast timer expires:

3> extend Mcast DRX cycle by drx-LongCycle-PTM × extend factor;

2> if the Mcast DRX cycle is extended by extend factor:

3> disable the Mcast timer.

For illustration, an example will be described in connection with FIG. 5C. FIG. 5C illustrates a schematic diagram 500C illustrating an example of multicast reception based on a timer and an extend factor according to embodiments of the present disclosure. In this example, it is assumed that a multicast timer is 50ms, an on-duration timer is 8ms, a long cycle timer is 20ms, and an extend factor is 2.

As shown in FIG. 5C, the terminal device 110 may enter an inactive state at timing t7. Then the terminal device 110 may start the multicast timer of 50ms. Meanwhile, the terminal device 110 may apply the long cycle timer of 20ms and the on-duration timer of 8ms for multicast DRX. When multicast data is received during an on-duration 521, the terminal device 110 may restart the multicast timer of 50ms. As no multicast data is received then, the multicast timer expires. Then the terminal device 110 may extend the long cycle timer of 20ms to 40ms since an on-duration 522. That is, the terminal device 110 may apply a long cycle timer of 40ms and the on-duration timer of 8ms for multicast reception.

It is to be understood that FIG. 5C is merely an example, and does not limit the present disclosure.

2. Counter based Solution

In some embodiments, the network device 120 may configure a counter (e.g., maximum count) that is used to determine when the terminal device 110 needs to use the extend factor to extend multicast DRX cycle in the inactive state.

In some embodiments, if the extend factor is not applied for multicast DRX and there is no downlink control transmission indicating downlink multicast transmission in one cycle of multicast DRX, the terminal device 110 may increment a value of a counter. If the value of the counter is above a predetermined value (e.g., greater than or equal to the predetermined value) , the terminal device 110 may determine that the monitoring period is to be reduced. In some embodiments, the predetermined value may be the configured maximum count. Then the terminal device 110 may apply the extend factor to extend the multicast DRX cycle. For example, the terminal device 110 may obtain an extended DRX cycle by multiplexing a configured DRX cycle with the extend factor.

In some embodiments, if the extend factor is applied for multicast DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is not applied for multicast DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for multicast DRX, the terminal device 110 may disable the extend factor for multicast DRX.

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

Upon entering RRC_INACTIVE, the UE shall:

2> if the MAC entity is in Active Time for this G-RNTI or G-CS-RNTI:

3> monitor the PDCCH for this G-RNTI or G-CS-RNTI;

3> if the PDCCH indicates a DL multicast transmission:

4> if the Mcast DRX cycle has already been extended by extend factor:

5> use the legacy Mcast DRX cycle (i.e. extend factor is disabled) ;

4> else:

5> reset the count;

3> else if there is no any PDCCH indication for a DL multicast transmission in one DRX cycle and the Mcast DRX cycle is not extended by extend factor:

4> increment the count by 1;

2> if the count ≥ max_count:

3> extend Mcast DRX cycle by drx-LongCycle-PTM × extend factor;

3> reset the count.

For illustration, an example will be described in connection with FIG. 5D. FIG. 5D illustrates a schematic diagram 500D illustrating an example of multicast reception based on a counter and an extend factor according to embodiments of the present disclosure. In this example, it is assumed that a maximum count is 2, an on-duration timer is 8ms, a long cycle timer is 20ms, and an extend factor is 2.

As shown in FIG. 5D, the terminal device 110 may enter an inactive state at timing t8. Then the terminal device 110 may apply the long cycle timer of 20ms and the on-duration timer of 8ms. As no multicast data is received during an on-duration 531, the terminal device 110 may increment the counter, e.g., count =1. When multicast data is received during an on-duration 532, the terminal device 110 may reset the counter, e.g., count=0. As no multicast data is received during an on-duration 533, the terminal device 110 may increment the counter, e.g., count =1. As no multicast data is received during an on-duration 534, the terminal device 110 may increment the counter, e.g., count =2 (i.e., the maximum count) . Then the extend factor may be applied to extend the long cycle timer of 20ms to 40ms at timing t9. That is, the terminal device 110 may apply a long cycle timer of 40ms and the on-duration timer of 8ms for multicast reception..

It is to be understood that FIG. 5D is merely an example, and does not limit the present disclosure.

Embodiment 6

In this embodiment, a timer may be introduced for management of multicast reception. In some embodiments, the configuration of multicast DRX may comprise a timer that is used to determine whether to stop multicast reception in an inactive state.

In some embodiments, if the terminal device 110 is allowed to receive a multicast service in an inactive state and multicast DRX is configured, the terminal device 110 may start a timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission, the terminal device 110 may restart the timer. In some embodiments, if the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced and stop the multicast reception in the inactive state. In some embodiments, after the multicast reception in the inactive state is stopped, the terminal device 110 may restart the multicast reception by a paging mechanism.

In this way, a terminal device in an inactive state may manage multicast reception based on a timer to reduce power consumption.

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

Upon entering RRC_INACTIVE, the UE shall:

1> if UE is allowed to receive Mcast service during RRC_INACTIVE:

2> start the Mcast_stop timer;

2> monitor the PDCCH for this G-RNTI or G-CS-RNTI;

2> if the PDCCH indicates a DL multicast transmission:

3> restart the Mcast_stop timer;

1> if the Mcast_stop timer expires:

2> UE stop Mcast reception during RRC_INACITVE. (i.e. Mcast reception in RRC_INACTIVE is disabled) .

EXAMPLE IMPLEMENTATION OF STORAGE OF MULTICAST CONFIGURATION

In some scenarios, a terminal device supporting multicast reception in an inactive state joins a multicast session but the multicast session is not ongoing. In this case, the terminal device may be released to an inactive state but still store related multicast configuration. In some scenarios, if no multicast session is ongoing, a terminal device may stop multicast reception in an inactive state but still store related multicast configuration.

However, for these scenarios, if the terminal device receives a multicast paging in an inactive state, the terminal device conventionally needs to initiate a random access procedure to go back to a connected state. This will cause inefficient multicast reception.

In view of this, embodiments of the present disclosure provide a solution of managing multicast reception in an inactive state to achieve efficient multicast reception. For convenience, the following description will be given in connection with FIG. 6.

FIG. 6 illustrates a schematic diagram illustrating another process 600 of communication for managing a multicast reception in an inactive state according to embodiments of the present disclosure. For the purpose of discussion, the process 600 will be described with reference to FIG. 1. The process 600 may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1. It is to be understood that the steps and the order of the steps in FIG. 6 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. It is assumed that the terminal device 110 is allowed to receive a multicast service in an inactive state.

As shown in FIG. 6, the network device 120 may transmit 610 a configuration for multicast reception in an inactive state to the terminal device 110. Then the terminal device 110 may perform the multicast reception in the inactive state based on the configuration.

The terminal device 110 may determine 620 whether there is no multicast transmission within a predetermined period of time. It is to be understood that the predetermined period of time may be determined in any suitable ways.

If there is no multicast transmission within the predetermined period of time, the terminal device 110 may store 630 the configuration for the multicast reception. In some embodiments, if there is no multicast transmission within the predetermined period of time, the terminal device 110 may stop multicast reception in an inactive state, and store the configuration for the multicast reception in the inactive state. In some embodiments, if there is no multicast transmission within the predetermined period of time, and the terminal device 110 in a connected state receives a RRC release message from the network device 120, the terminal device 110 may enter an inactive state and store the current configuration for multicast reception.

The network device 120 may transmit 640 a paging message to the terminal device 110. Upon reception of the paging message, the terminal device 110 may determine 650 whether the terminal device 110 receives a multicast service in an inactive state.

If the terminal device 110 receives the multicast service in the inactive state, the terminal device 110 may perform 660 multicast reception in the inactive state based on the stored configuration. For example, the terminal device 110 may restore the stored configuration for the multicast reception in the inactive state.

In this way, initiation of a random access procedure may be avoided, and efficient multicast reception may be achieved.

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

Part 1 RRCRelease

Upon reception of the RRCRelease, the UE shall:

1> if the RRCRelease includes suspendConfig:

2> if UE is configured to receive Mcast session during RRC_INACTVE but there is temporarily no Mcast session on going:

3> store the Mcast related configuration as UE Inactive AS context;

2> suspend all SRB (s) and DRB (s) and multicast MRB (s) , except SRB0;

…

1> indicate the suspension of the RRC connection to upper layers;

1> enter RRC_INACTIVE and perform cell selection.

Part 2 Paging

Upon receiving the paging message, the UE shall:

1> if in RRC_INACTIVE and the UE has joined one or more MBS session (s) indicated by the TMGI included in the pagingGroupList; and

1> if none of the ue-Identity included in any of the PagingRecord, if included in the Paging message, matches the UE identity allocated by upper layers; and

1> if UE is configured to receive Mcast session during RRC_INACTVE and has stored the Mcast related configuration:

2> maintain in RRC_INACTIVE;

2> restore the Mcast related configuration and related MRB;

2> start to receive Mcast reception based on the Mcast related configuration in RRC_INACTVE.

EXAMPLE IMPLEMENTATION OF METHODS

Corresponding to the above processes, embodiments of the present disclosure provide methods of communication implemented at a terminal device. These methods will be described below with reference to FIGs. 7 and 8.

FIG. 7 illustrates an example method 700 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 700 may be performed at the terminal device 110 as shown in FIG. 1. For the purpose of discussion, in the following, the method 700 will be described with reference to FIG. 1. 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 terminal device 110 determines whether the terminal device 110 is allowed to receive a multicast service in an inactive state and DRX for the multicast service is configured. If the terminal device 110 is allowed to receive a multicast service in an inactive state and DRX for the multicast service is configured, the method 700 proceeds to block 720.

At block 720, the terminal device 110 determines whether a monitoring period is to be reduced. If the monitoring period is to be reduced, the method 700 proceeds to block 730.

At block 730, the terminal device 110 changes the DRX to reduce the monitoring period.

In some embodiments, the terminal device 110 may receive, from the network device 120, a configuration for a WUS for multicast DRX monitoring, the configuration comprising at least one of the following: a RNTI for reception of the WUS, or an exception indication indicating whether an on-duration timer for the DRX is started if the WUS is not received.

In some embodiments, the terminal device 110 may receive, from the network device 120, a configuration for a WUS for multicast DRX monitoring. If the terminal device 110 is allowed to receive the multicast service in the inactive state, the terminal device 110 may store the configuration upon entering the inactive state.

In some embodiments, the terminal device 110 may monitor WUS (or any other signals having similar functions) before an on-duration timer for the DRX starts. The WUS is configured for multicast DRX monitoring. In some embodiments, in response to receiving the WUS comprising an indication of stopping a multicast session, the terminal device 110 may determine that the monitoring period is to be reduced. In some embodiments, in response to receiving the WUS comprising an indication of modifying a multicast configuration, the terminal device 110 may initiate a RRC resume procedure to receive a modified multicast configuration in a connected state. In some embodiments, if an exception indication is configured with a first value and the WUS is not received, the terminal device 110 may start the on-duration timer for the DRX. In some embodiments, if the WUS comprising an indication of starting the on-duration timer for the DRX is received, the terminal device 110 may start the on-duration timer for the DRX.

In some embodiments, the terminal device 110 may receive system information or DCI from the network device 120. In some embodiments, if the system information or DCI comprises an indication of stopping a multicast session for a set of multicast services and the set of multicast services comprises the multicast service, the terminal device 110 may determine that the monitoring period is to be reduced and stop a monitoring of the multicast service in the DRX. In some embodiments, if the system information or DCI comprises an indication of modifying a multicast configuration for a set of multicast services and the set of multicast services comprises the multicast service, the terminal device 110 may initiate a RRC resume procedure to receive a modified multicast configuration in a connected state.

In some embodiments, the terminal device 110 may receive, from the network device 120, a first configuration and a second configuration for the DRX, the second configuration having a reduced monitoring period for the DRX than the first configuration. In some embodiments, if the second configuration is configured, the terminal device 110 may start a timer. If the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced. In some embodiments, if the second configuration is applied for the DRX, the terminal device 110 may disable the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for the discontinuous reception, the terminal device 110 may restart the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for the DRX, the terminal device 110 may apply the first configuration for the DRX and starting the timer.

In some alternative embodiments, if the first configuration is applied for the DRX and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the DRX, the terminal device 110 may increment a value of a counter. If the value of the counter is above a predetermined value, the terminal device 110 may determine that the monitoring period is to be reduced and may apply the second configuration for the DRX. In some embodiments, if the second configuration is applied for the DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for the DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for the DRX, the terminal device 110 may apply the first configuration for the DRX.

In some embodiments, the terminal device 110 may receive, from the network device 120, an extend factor for extending a cycle of the DRX. In some embodiments, if a determination that the extend factor is configured, the terminal device 110 may start a timer. If the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced and may extend the cycle of the DRX with the extend factor. In some embodiments, if the extend factor is applied for the DRX, the terminal device 110 may disable the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is not applied for the DRX, the terminal device 110 may restart the timer. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for the DRX, the terminal device 110 may disable the extend factor for the DRX and starting the timer.

In some alternative embodiments, if the extend factor is not applied for the DRX and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the DRX, the terminal device 110 may increment a value of a counter. In some embodiments, if the value of the counter is above a predetermined value, the terminal device 110 may determine that the monitoring period is to be reduced and may extend the cycle of the DRX with the extend factor. In some embodiments, if the extend factor is applied for the DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is not applied for the DRX, the terminal device 110 may reset the counter. In some embodiments, if a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for the DRX, the terminal device 110 may disable the extend factor for the DRX.

In some embodiments, if the terminal device 110 is allowed to receive the multicast service in the inactive state and DRX for the multicast service is configured, the terminal device 110 may start a timer. If the timer expires, the terminal device 110 may determine that the monitoring period is to be reduced, and may stop the reception of the multicast service in the inactive state. In some embodiments, if a downlink control transmission indicates downlink multicast transmission, the terminal device 110 may restart the timer.

With the method 700, power saving may be achieved for multicast reception in an inactive state.

FIG. 8 illustrates another example method 800 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 800 may be performed at the terminal device 110 as shown in FIG. 1. For the purpose of discussion, in the following, the method 800 will be described with reference to FIG. 1. It is to be understood that the method 800 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 810, the terminal device 110 determines whether a paging message is received while the terminal device 110 is allowed to receive a multicast service in an inactive state. If the paging message is received, the method 800 proceeds to block 820.

At block 820, the terminal device 110 performs multicast reception in the inactive state based on a configuration stored for the multicast reception. In some embodiments, the terminal device 110 may restore the configuration stored for the multicast reception.

In some embodiments, if the terminal device 110 is allowed to receive the multicast service in the inactive state and there is no multicast transmission within a predetermined period of time, the terminal device 110 may store the configuration for the multicast reception upon entering the inactive state.

In this way, efficient multicast reception in an inactive state may be achieved.

EXAMPLE IMPLEMENTATION OF DEVICE AND APPARATUS

FIG. 9 is a simplified block diagram of a device 900 that is suitable for implementing embodiments of the present disclosure. The device 900 can be considered as a further example implementation of the terminal device 110 or the network device 120 as shown in FIG. 1. Accordingly, the device 900 can be implemented at or as at least a part of the terminal device 110 or the network device 120.

As shown, the device 900 includes a processor 910, a memory 920 coupled to the processor 910, a suitable transmitter (TX) and receiver (RX) 940 coupled to the processor 910, and a communication interface coupled to the TX/RX 940. The memory 910 stores at least a part of a program 930. The TX/RX 940 is for bidirectional communications. The TX/RX 940 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 930 is assumed to include program instructions that, when executed by the associated processor 910, enable the device 900 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1 to 8. The embodiments herein may be implemented by computer software executable by the processor 910 of the device 900, or by hardware, or by a combination of software and hardware. The processor 910 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 910 and memory 920 may form processing means 950 adapted to implement various embodiments of the present disclosure.

The memory 920 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 920 is shown in the device 900, there may be several physically distinct memory modules in the device 900. The processor 910 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 900 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: in accordance with a determination that a terminal device is allowed to receive a multicast service in an inactive state and discontinuous reception for the multicast service is configured, determine whether a monitoring period is to be reduced; and in accordance with a determination that the monitoring period is to be reduced, change the discontinuous reception to reduce the monitoring period.

In some embodiments, a terminal device comprises a circuitry configured to: in accordance with a determination that a paging message is received while a terminal device is allowed to receive a multicast service in an inactive state, perform, at the terminal device, multicast reception in the inactive state based on a configuration stored for the multicast reception.

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 may provide the following solutions.

In one solution, a method of communication comprises: in accordance with a determination that a terminal device is allowed to receive a multicast service in an inactive state and discontinuous reception for the multicast service is configured, determining, at the terminal device, whether a monitoring period is to be reduced; and in accordance with a determination that the monitoring period is to be reduced, changing the discontinuous reception to reduce the monitoring period.

In some embodiments, determining whether the monitoring period is to be reduced comprises: monitoring a wake-up signal before an on-duration timer for the discontinuous reception starts, the wake-up signal being configured for multicast discontinuous reception monitoring; and in response to receiving the wake-up signal comprising an indication of stopping a multicast session, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in response to receiving the wake-up signal comprising an indication of modifying a multicast configuration, initiating a radio resource control resume procedure to receive a modified multicast configuration in a connected state; in accordance with a determination that an exception indication is configured with a first value and the wake-up signal is not received, starting the on-duration timer for the discontinuous reception; or in accordance with a determination that the wake-up signal comprising an indication of starting the on-duration timer for the discontinuous reception is received, starting the on-duration timer for the discontinuous reception.

In some embodiments, determining whether the monitoring period is to be reduced comprises: receiving system information or downlink control information from a network device; and in accordance with a determination that the system information or downlink control information comprises an indication of stopping a multicast session for a set of multicast services and the set of multicast services comprises the multicast service, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in accordance with a determination that the system information or downlink control information comprises an indication of modifying a multicast configuration for a set of multicast services and the set of multicast services comprises the multicast service, initiating a radio resource control resume procedure to receive a modified multicast configuration in a connected state.

In some embodiments, changing the discontinuous reception comprises: stopping a monitoring of the multicast service in the discontinuous reception.

In some embodiments, the method as described above further comprises: receiving, from a network device, a first configuration and a second configuration for the discontinuous reception, the second configuration having a reduced monitoring period for the discontinuous reception than the first configuration.

In some embodiments, determining whether the monitoring period is to be reduced comprises: in accordance with a determination that the second configuration is configured, starting a timer; and in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in accordance with a determination that the second configuration is applied for the discontinuous reception, disabling the timer; in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for the discontinuous reception, restarting the timer; or in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for the discontinuous reception, applying the first configuration for the discontinuous reception and starting the timer.

In some embodiments, determining whether the monitoring period is to be reduced comprises: in accordance with a determination that the first configuration is applied for the discontinuous reception and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the discontinuous reception, incrementing a value of a counter; and in accordance with a determination that the value of the counter is above a predetermined value, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in accordance with a determination that the second configuration is applied for the discontinuous reception, resetting the counter; in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for the discontinuous reception, resetting the counter; or in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for the discontinuous reception, applying the first configuration for the discontinuous reception.

In some embodiments, changing the discontinuous reception comprises: applying the second configuration for the discontinuous reception.

In some embodiments, the method as described above further comprises: receiving, from a network device, an extend factor for extending a cycle of the discontinuous reception.

In some embodiments, determining whether the monitoring period is to be reduced comprises: in accordance with a determination that the extend factor is configured, starting a timer; and in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in accordance with a determination that the extend factor is applied for the discontinuous reception, disabling the timer; in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the extend factor is not applied for the discontinuous reception, restarting the timer; or in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for the discontinuous reception, disabling the extend factor for the discontinuous reception and starting the timer.

In some embodiments, determining whether the monitoring period is to be reduced comprises: in accordance with a determination that the extend factor is not applied for the discontinuous reception and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the discontinuous reception, incrementing a value of a counter; and in accordance with a determination that the value of the counter is above a predetermined value, determining that the monitoring period is to be reduced.

In some embodiments, the method as described above further comprises: in accordance with a determination that the extend factor is applied for the discontinuous reception, resetting the counter; in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the extend factor is not applied for the discontinuous reception, resetting the counter; or in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the extend factor is applied for the discontinuous reception, disabling the extend factor for the discontinuous reception.

In some embodiments, changing the discontinuous reception comprises: extending the cycle of the discontinuous reception with the extend factor.

In some embodiments, determining whether the monitoring period is to be reduced comprises: in accordance with a determination that the terminal device is allowed to receive the multicast service in the inactive state and discontinuous reception for the multicast service is configured, starting a timer; and in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.

In some embodiments, changing the discontinuous reception comprises: stopping the reception of the multicast service in the inactive state.

In some embodiments, the method as described above further comprises: in accordance with a determination that a downlink control transmission indicates downlink multicast transmission, restarting the timer.

In some embodiments, the method as described above further comprises: receiving, from a network device, a configuration for a wake-up signal for multicast discontinuous reception monitoring; and in accordance with a determination that the terminal device is allowed to receive the multicast service in the inactive state, storing the configuration upon entering the inactive state.

In some embodiments, the method as described above further comprises: receiving, from a network device, a configuration for a wake-up signal for multicast discontinuous reception monitoring, the configuration comprising at least one of the following: a radio network temporary identifier for reception of the wake-up signal, or an exception indication indicating whether an on-duration timer for the discontinuous reception is started if the wake-up signal is not received.

In another solution, a method of communication comprises: in accordance with a determination that a paging message is received while a terminal device is allowed to receive a multicast service in an inactive state, performing, at the terminal device, multicast reception in the inactive state based on a configuration stored for the multicast reception.

In some embodiments, the method as described above further comprises: in accordance with a determination that the terminal device is allowed to receive the multicast service in the inactive state and there is no multicast transmission within a predetermined period of time, storing the configuration for the multicast reception upon entering the inactive state.

In some embodiments, performing the multicast reception comprises: restoring the configuration stored for the multicast reception.

In another solution, a device of communication comprises: a processor configured to cause the device to perform any of the above methods.

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. 1 to 8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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

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

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

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

Claims

A method of communication, comprising:

in accordance with a determination that a terminal device is allowed to receive a multicast service in an inactive state and discontinuous reception for the multicast service is configured, determining, at the terminal device, whether a monitoring period is to be reduced; and

in accordance with a determination that the monitoring period is to be reduced, changing the discontinuous reception to reduce the monitoring period.
The method of claim 1, wherein determining whether the monitoring period is to be reduced comprises:

monitoring a wake-up signal before an on-duration timer for the discontinuous reception starts, the wake-up signal being configured for multicast discontinuous reception monitoring; and

in response to receiving the wake-up signal comprising an indication of stopping a multicast session, determining that the monitoring period is to be reduced.
The method of claim 2, further comprising:

in response to receiving the wake-up signal comprising an indication of modifying a multicast configuration, initiating a radio resource control resume procedure to receive a modified multicast configuration in a connected state;

in accordance with a determination that an exception indication is configured with a first value and the wake-up signal is not received, starting the on-duration timer for the discontinuous reception; or

in accordance with a determination that the wake-up signal comprising an indication of starting the on-duration timer for the discontinuous reception is received, starting the on-duration timer for the discontinuous reception.
The method of claim 1, wherein determining whether the monitoring period is to be reduced comprises:

receiving system information or downlink control information from a network device; and

in accordance with a determination that the system information or downlink control information comprises an indication of stopping a multicast session for a set of multicast services and the set of multicast services comprises the multicast service, determining that the monitoring period is to be reduced.
The method of claim 4, further comprising:

in accordance with a determination that the system information or downlink control information comprises an indication of modifying a multicast configuration for a set of multicast services and the set of multicast services comprises the multicast service, initiating a radio resource control resume procedure to receive a modified multicast configuration in a connected state.
The method of claim 2 or 4, wherein changing the discontinuous reception comprises:

stopping a monitoring of the multicast service in the discontinuous reception.
The method of claim 1, further comprising:

receiving, from a network device, a first configuration and a second configuration for the discontinuous reception, the second configuration having a reduced monitoring period for the discontinuous reception than the first configuration.
The method of claim 7, wherein determining whether the monitoring period is to be reduced comprises:

in accordance with a determination that the second configuration is configured, starting a timer; and

in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.
The method of claim 8, further comprising:

in accordance with a determination that the second configuration is applied for the discontinuous reception, disabling the timer;

in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the first configuration is applied for the discontinuous reception, restarting the timer; or

in accordance with a determination that a downlink control transmission indicates downlink multicast transmission and the second configuration is applied for the discontinuous reception, applying the first configuration for the discontinuous reception and starting the timer.
The method of claim 7, wherein determining whether the monitoring period is to be reduced comprises:

in accordance with a determination that the first configuration is applied for the discontinuous reception and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the discontinuous reception, incrementing a value of a counter; and

in accordance with a determination that the value of the counter is above a predetermined value, determining that the monitoring period is to be reduced.
The method of claim 8 or 10, wherein changing the discontinuous reception comprises:

applying the second configuration for the discontinuous reception.
The method of claim 1, further comprising:

receiving, from a network device, an extend factor for extending a cycle of the discontinuous reception.
The method of claim 12, wherein determining whether the monitoring period is to be reduced comprises:

in accordance with a determination that the extend factor is configured, starting a timer; and

in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.
The method of claim 12, wherein determining whether the monitoring period is to be reduced comprises:

in accordance with a determination that the extend factor is not applied for the discontinuous reception and there is no downlink control transmission indicating downlink multicast transmission in one cycle of the discontinuous reception, incrementing a value of a counter; and

in accordance with a determination that the value of the counter is above a predetermined value, determining that the monitoring period is to be reduced.
The method of claim 12 or 14, wherein changing the discontinuous reception comprises:

extending the cycle of the discontinuous reception with the extend factor.
The method of claim 1, wherein determining whether the monitoring period is to be reduced comprises:

in accordance with a determination that the terminal device is allowed to receive the multicast service in the inactive state and discontinuous reception for the multicast service is configured, starting a timer; and

in accordance with a determination that the timer expires, determining that the monitoring period is to be reduced.
The method of claim 16, wherein changing the discontinuous reception comprises:

stopping the reception of the multicast service in the inactive state.
The method of claim 1, further comprising:

receiving, from a network device, a configuration for a wake-up signal for multicast discontinuous reception monitoring; and

in accordance with a determination that the terminal device is allowed to receive the multicast service in the inactive state, storing the configuration upon entering the inactive state.
A method of communication, comprising:

in accordance with a determination that a paging message is received while a terminal device is allowed to receive a multicast service in an inactive state, performing, at the terminal device, multicast reception in the inactive state based on a configuration stored for the multicast reception.
A device of communication comprising:

a processor configured to cause the device to perform the method according to any of claims 1 to 18 or claim 19.