Patent Description:
Skipping monitoring of downlink control channel is a method for reducing battery consumption by indicating a terminal device to skip monitoring of a DL control channel for a certain time period. If skipping of a DL control channel is supported, the terminal device may receive, during or prior to an RA procedure, a command indicating the terminal device to skip monitoring a DL control channel. Thus, it is needed to clarify how the terminal device should operate in respect to skipping monitoring of a DL control channel during an ongoing RA procedure.

3GPP R2-<NUM> describes a proposal for aligning DRX active time with RA procedure. 3GPP R2-<NUM> describes a proposal for early stop of random access response monitoring. 3GPP TS <NUM> V8. <NUM> describes discontinuous reception (DRX) functionality for a user equipment (UE). 3GPP R1-<NUM> includes a discussion on PDCCH monitoring skipping.

In general, example embodiments of the present disclosure provide a solution for skipping monitoring of a DL control channel during an RA procedure.

In a first aspect, there is provided a first device according to claim <NUM>.

There is also provided a method according to claim <NUM>.

Further, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

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

As used herein, the term "network device" refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR Next Generation NodeB (gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. An RAN split architecture comprises a gNB-CU (Centralized unit, hosting RRC, SDAP and PDCP) controlling a plurality of gNB-DUs (Distributed unit, hosting RLC, MAC and PHY).

Although functionalities described herein can be performed, in various example embodiments, in a fixed and/or a wireless network node may, in other example embodiments, functionalities may be implemented in a user equipment apparatus (such as a cell phone or tablet computer or laptop computer or desktop computer or mobile IOT device or fixed IOT device). This user equipment apparatus can, for example, be furnished with corresponding capabilities as described in connection with the fixed and/or the wireless network node(s), as appropriate. The user equipment apparatus may be the user equipment and/or or a control device, such as a chipset or processor, configured to control the user equipment when installed therein. Examples of such functionalities include the bootstrapping server function and/or the home subscriber server, which may be implemented in the user equipment apparatus by providing the user equipment apparatus with software configured to cause the user equipment apparatus to perform from the point of view of these functions/nodes.

<FIG> shows an example communication network <NUM> in which embodiments of the present disclosure can be implemented. The network <NUM> includes a first device <NUM> and a second device <NUM> that can communicate with each other. In this example, the first device <NUM> is illustrated as a terminal device, and the second device <NUM> is illustrated as a network device serving the terminal device. Thus, the serving area of the second device <NUM> is called as a cell <NUM>. It is to be understood that the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The system <NUM> may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices may be located in the cell <NUM> and served by the second device <NUM>.

Communications in the communication system <NUM> may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (<NUM>), the second generation (<NUM>), the third generation (<NUM>), the fourth generation (<NUM>) and the fifth generation (<NUM>) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) <NUM> and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

In the communication network <NUM>, the first device <NUM> and the second device <NUM> can communicate data and control information to each other. In the case where the first device <NUM> is the terminal device and the second device <NUM> is the network device, a link from the second device <NUM> to the first device <NUM> is referred to as a downlink (DL), while a link from the first device <NUM> to the second device <NUM> is referred to as an uplink (UL).

There is an ongoing initiative of 3GPP related to power savings of terminal devices in NR (such as power saving study item 3GPP RP-<NUM> and 3GPP TR <NUM>). The aim of the 3GPP study is to achieve power savings of terminal devices primarily for enhanced mobile broadband (eMBB) scenarios. As part of the study, PDCCH monitoring skipping has been introduced.

To support power saving, the second device <NUM> may transmit a command indicating the first device <NUM> to skip monitoring a DL control channel for a time period. Skipping monitoring of a DL control channel is especially beneficial in the cases of scheduling gaps due to beam sweeping or other scheduling decision at the side of a transmitter. For example, the second device <NUM> may have a number of devices to schedule e.g. in distinct beams but the scheduling cannot be completed simultaneously. Similarly, skipping monitoring of a DL control channel is beneficial also in the cases when no data is available for the UE. The second device <NUM> may indicate to one or more of the devices that they are allowed to skip monitoring the DL control channel for a while, i.e. these devices will not be scheduled until a number of time slots, and thus, they may enter a sleep mode for battery saving.

<FIG> illustrates a skipping monitoring of a DL control channel according to some example embodiments of the present disclosure. As shown, in a scheduling period <NUM>, the second device <NUM> schedules the first device <NUM> continuously. If the second device <NUM> will not schedule the first device <NUM> for a while, at the end of the scheduling period <NUM>, the second device <NUM> may transmit to the first device <NUM> a skipping command indicating the first device <NUM> to skip monitoring a DL control channel for a time period <NUM>. For the purpose of discussion, the time period in which the first device <NUM> skips monitoring a DL control channel is also referred to as a skipping period. The skipping period <NUM> may be indicated explicitly in the skipping command from the second device or could be configured upfront by the second device, e.g. via RRC signaling. For example, the skipping period <NUM> may include the number of monitoring occasions or time duration.

Upon expiration of the skipping period <NUM>, the first device <NUM> resumes to monitor the DL control channel in a scheduling period <NUM>.

If skipping monitoring of a DL control channel is supported, the second device <NUM> may transmit the skipping command to the first device <NUM> during and/or prior to an RA procedure. Thus, it is needed to clarify how the terminal device should operate in respect to skipping monitoring of a DL control channel during an ongoing RA procedure.

If skipping monitoring of a DL control channel is supported, the first device <NUM> may indicate to the second device <NUM> its support of skipping of a DL control channel e.g. by means of a UE capability message.

The second device <NUM> considers the capability of the first device <NUM> when configuring the PDCCH skipping command to the first device <NUM> and when scheduling / assigning radio resources to the first device <NUM> (accounting e.g. for the skipping period).

According to some example embodiments, there is provided a solution for skipping monitoring of a DL control channel during an RA procedure. According to the solution, the first device determines whether a skipping period indicated in a skipping command overlaps with a time window associated with an RA procedure. In turn, the first device ignores or performs the skipping command based on the determination. With this solution, if the skipping period does not entirely overlap with the time window associated with the RA procedure, the first device will perform the skipping command. Thus, the scheduling flexibility may be enabled. In addition, if the skipping period entirely overlaps with the time window, the first device will ignore the skipping command. Thus, reception of an RA response from a second device is ensured. On the other hand, if the skipping period partially overlaps with the time window, the first device will perform the skipping command until a start of the time window. In this way, the scheduling flexibility may be enabled and reception of the RA response is ensured.

Reference is now made to <FIG>, which shows a signaling chart illustrating a process <NUM> for skipping monitoring of a DL control channel during an RA procedure according to some example embodiments of the present disclosure. For the purpose of discussion, the process <NUM> will be described with reference to <FIG>. The process <NUM> may involve the first device <NUM> and the second device <NUM> as illustrated in <FIG>. Although the process <NUM> has been described in the communication system <NUM> of <FIG>, this process may be likewise applied to other communication scenarios. Although skipping monitoring of a DL control channel configured for the first device is discussed, a similar process can be applied for skipping monitoring of a control channel of the second device.

The first device <NUM> receives in <NUM> a skipping command from a second device <NUM>. The skipping command indicates the first device <NUM> to skip monitoring a DL control channel between the second device <NUM> and the first device <NUM> for a time period (which is also referred to as a skipping period).

In some example embodiments when the first device <NUM> is a terminal device and the second device <NUM> is a network device, the DL control channel to be monitored may be a physical downlink control channel (PDCCH). The PDCCH is called a scheduling channel in a sense that it carries scheduling information. Control information transmitted through the PDCCH is referred to as downlink control information (DCI). By monitoring the DL control channel, the first device <NUM> may determine when and/or how it is scheduled to receive data from the second device <NUM>. The skipping command may be transmitted to the first device <NUM> in control information, such as in PDCCH.

The skipping command may be received when the first device <NUM> is in an ongoing RA procedure or is going to enter an RA procedure. As part of the RA procedure, the first device <NUM> needs to monitor the DL control channel in a time window associated with the RA procedure, so as to obtain from the second device <NUM> information necessary for the RA procedure. For the purpose of discussion, the time window associated with the RA procedure is also referred to as an RA time window.

If the RA procedure is by a first trigger condition, to ensure reception of the information necessary for the RA procedure, the first device <NUM> determines <NUM> whether the skipping period overlaps with the RA time window.

In some example embodiments, the first trigger condition comprises the first device <NUM> initiating the RA procedure as a contention-based RA. In some other example embodiments, the first trigger condition comprises the first device <NUM> initiating the RA procedure as a contention-free RA.

In some example embodiments, the RA time window may be an RA response window. In such embodiments, the first device <NUM> needs to monitor the DL control channel in the RA time window <NUM>, so as to obtain an RA response from the second device <NUM>.

In some other example embodiments, the RA time window may be a time window defined by a RA contention resolution timer. In such embodiments, the first device <NUM> needs to monitor the DL control channel in the RA time window, so as to obtain a contention resolution result from the second device <NUM>. Alternatively, the first device <NUM> needs to monitor the DL control channel in the RA time window, so as to obtain from the second device <NUM> a retransmission grant for the scheduled transmission.

In some still other example embodiments, the RA time window may be a time window corresponding to the whole RA procedure time if there is an ongoing RA procedure.

The first device <NUM> ignores or performs <NUM> the skipping command based on the determination. To better understand actions performed by the first device <NUM> based on the determination, relationships between a skipping period and an RA time window will be described with reference to <FIG>, <FIG>.

As shown in <FIG>, a skipping period <NUM> entirely overlaps with an RA time window <NUM>. In this case, if the first device <NUM> performs the skipping command to skip monitoring the DL control channel, the first device <NUM> cannot obtain information necessary for the RA procedure from the second device <NUM>. Thus, in order to ensure the reception of information necessary for the RA procedure, the first device <NUM> ignores the skipping command.

As shown in <FIG>, a skipping period <NUM> partially overlaps with the RA time window <NUM> and a start of the skipping period <NUM> is earlier than a start of the RA time window <NUM>. In this case, in order to ensure the reception of information necessary for the RA procedure, the first device <NUM> performs the skipping command until the start of the RA time window <NUM>.

As shown in <FIG>, a skipping period <NUM> does not overlap with the RA time window <NUM>. In this case, the first device <NUM> performs the skipping command. In this way, the scheduling flexibility may be enabled.

As shown in <FIG>, a skipping period <NUM> partially overlaps with the RA time window <NUM> and the start of the time window <NUM> is earlier than a start of the skipping period <NUM>. In this case, in order to ensure the reception of information necessary for the RA procedure, the first device <NUM> performs the skipping command until an end of the RA time window <NUM>.

As shown in <FIG>, a skipping period <NUM> partially overlaps with the RA time window <NUM> and the RA time window <NUM> is within the skipping period <NUM>. In this case, in order to ensure the reception of information necessary for the RA procedure, the first device <NUM> performs the skipping command until the start of the RA time window <NUM> and performs the skipping command after the end of the RA time window <NUM>.

In some example embodiments, the RA procedure is triggered by a trigger condition. Examples of the trigger conditions may include, but are not limited to; RRC Connection Re-establishment procedure; UL data arrival during RRC_CONNECTED when UL synchronisation status is "non-synchronised"; UL data arrival during RRC_CONNECTED when there are no Physical Uplink Control Channel (PUCCH) resources for Scheduling Request (SR) available; SR failure; Request by RRC upon synchronous reconfiguration (e.g. handover); transition from RRC_INACTIVE; to establish time alignment at SCell addition; request for Other System Information (SI); and beam failure recovery (BFR).

To better understand how skipping monitoring of a DL control channel works together with the RA procedure, a signaling chart illustrating a process <NUM> for skipping monitoring of a DL control channel during an RA procedure according to some other example embodiments of the present disclosure will be described with reference to <FIG>. For the purpose of discussion, the process <NUM> will be described with reference to <FIG>. The process <NUM> may involve the first device <NUM> and the second device <NUM> as illustrated in <FIG>. The process <NUM> may be considered as an example implementation of the process <NUM>.

In the process <NUM>, the RA procedure is initiated by the first device <NUM>, and may be a contention-based RA procedure or a contention-free RA procedure.

The first device <NUM> transmits <NUM> an RA preamble to the second device <NUM> so as to initiate an RA procedure. Upon reception of the RA preamble, the second device <NUM> may estimate transmission timing of the first device <NUM> to enable uplink synchronization of the first device <NUM>.

If the second device <NUM> will not schedule the first device <NUM> for a while, the second device <NUM> may transmit <NUM> a skipping command to the first device <NUM>. The skipping command indicates the first device <NUM> to skip monitoring the DL control channel for a skipping period.

Upon reception of the skipping command, the first device <NUM> determines <NUM> whether the skipping period overlaps with an RA time window. For example, in this example implementation, the first device <NUM> may determine whether the skipping period overlaps with an RA response window.

If the first device <NUM> determines that the skipping period entirely overlaps with the RA response window, the first device <NUM> may ignore <NUM> the skipping command. Thus, the reception of the RA response is ensured.

On the other hand, if the first device <NUM> determines that the skipping period partially overlaps with the RA response window, the first device <NUM> may perform <NUM> the skipping command until a start of the RA response window. In this way, the scheduling flexibility may be enabled and the reception of the RA response is ensured.

Alternatively, if the first device <NUM> determines that the skipping period does not overlap with the RA response window, the first device <NUM> may perform <NUM> the skipping command. As such, the scheduling flexibility may be enabled.

Based on the estimated transmission timing of the first device <NUM>, the second device <NUM> transmits <NUM> an RA response to the first device <NUM>. The RA response may include information about timing advance for the first device <NUM>, and UL resources to be used by the first device <NUM> in an action of <NUM>.

Upon reception of the RA response, the first device <NUM> transmits <NUM> to the second device <NUM> a scheduled transmission by using the UL resources indicated in the RA response. The scheduled transmission includes a Cell Radio Network Temporary Identifier (C-RNTI) of the first device <NUM>.

If the first device <NUM> is successful in the contention, the second device <NUM> may transmit <NUM> a contention resolution message to the first device <NUM>. The contention resolution message includes the C-RNTI of the first device <NUM>. For example, a payload of the contention resolution message may be scrambled with the C-RNTI of the first device <NUM>.

It is to be understood that although the process <NUM> has been described in connection with the RA response window, a similar process can be applied to a time window defined by RA contention resolution timer.

It is also to be understood that although the process <NUM> has been described by taking a <NUM>-step RA procedure for example, a similar process may be applied to a <NUM>-step RA procedure.

It is further to be understood that although the process <NUM> has been described by taking the action <NUM> occurring prior to the action <NUM>, in other example implementations, the action <NUM> may occur subsequent to the action <NUM>.

In some example embodiments, the RA procedure may be initiated for beam failure recovery. For beam failure detection, a network device configures a terminal device with beam failure detection reference signals (SSB or CSI-RS) and the terminal device declares beam failure when the number of beam failure instance indications from the physical layer reaches a configured threshold before a configured timer expires.

SSB-based Beam Failure Detection is based on the SSB associated to the initial DL bandwidth part (BWP) and can only be configured for the initial DL BWPs and for DL BWPs containing the SSB associated to the initial DL BWP. For other DL BWPs, Beam Failure Detection can only be performed based on CSI-RS.

After beam failure is detected, the terminal device may trigger beam failure recovery by initiating an RA procedure on the PCell. In addition, the terminal device may select a suitable beam to perform beam failure recovery. If the network device has provided dedicated RA resources for certain beams, those will be prioritized by the terminal device. Upon completion of the RA procedure, beam failure recovery is considered complete.

Reference is now made to <FIG>, which shows a signaling chart illustrating a process <NUM> for skipping monitoring of a DL control channel during an RA procedure according to some example embodiments of the present disclosure. For the purpose of discussion, the process <NUM> will be described with reference to <FIG>. The process <NUM> may involve the first device <NUM> and the second device <NUM> as illustrated in <FIG>. The process <NUM> may be considered as an example implementation of the process <NUM>.

In the process <NUM>, the RA procedure is initiated by the first device <NUM> for beam failure recovery, and may be a contention-free RA procedure.

The second device <NUM> transmits <NUM> to the first device <NUM> a dedicated RA preamble and information about a dedicated physical random access channel (PRACH) resource.

The first device <NUM> transmits <NUM> to the second device <NUM> the dedicated RA preamble on the dedicated PRACH resource.

In some example embodiments, the second device <NUM> may transmit the skipping command via a dedicated message on the DL control channel. For example, the dedicated message may include a PDCCH order. In some other example embodiments, the second device <NUM> may transmit the skipping command via a handover command.

If the first device <NUM> determines that the skipping period entirely overlaps with the RA response window, the first device <NUM> may ignore <NUM> the skipping command. On the other hand, if the first device <NUM> determines that the skipping period partially overlaps with the RA response window, the first device <NUM> may perform <NUM> the skipping command until a start of the RA response window. Alternatively, if the first device <NUM> determines that the skipping period does not overlap with the RA response window, the first device <NUM> may perform <NUM> the skipping command.

In the invention, the second device <NUM> transmits <NUM> an RA response to the first device <NUM> in a search space associated with the beam failure recovery. For example, the search space may be indicated by a recoverySearchSpaceId. The second device <NUM> may configure the first device <NUM> with the recoverySearchSpaceId prior to the RA procedure. The RA response includes the C-RNTI of the first device <NUM>. In addition, if the second device <NUM> has DL data to be transmitted to the first device <NUM>, the RA response may include DL scheduling information. Alternatively, if the second device <NUM> has UL data to be received from the first device <NUM>, the RA response may include UL scheduling information.

Alternatively, upon reception of the dedicated RA preamble, if the second device <NUM> has no DL data to be transmitted to the first device <NUM> or no UL data to be received from the first device <NUM>, the second device <NUM> may not transmit the RA response. Instead, the second device <NUM> may only transmit the skipping command. The skipping command comprises the C-RNTI of the first device <NUM> and indicates a successful completion of the RA. For example, when the skipping command is sent through a DCI, the DCI may be scrambled with the C-RNTI of the first device <NUM>.

In the process <NUM>, the RA procedure is initiated by the second device <NUM>, and may be a contention-based RA procedure or a contention-free RA procedure.

The second device <NUM> transmits <NUM> to the first device <NUM> an indication indicating the first device <NUM> transmits a RA request to the second device <NUM>. In some example embodiments, the second device <NUM> may transmit the indication via a dedicated message on the DL control channel. For example, the dedicated message may include a PDCCH order. In some other example embodiments, the second device <NUM> may transmit the indication via a handover command.

If a dedicated RA preamble is available, the second device <NUM> may transmit the dedicated RA preamble in the indication to the first device <NUM>.

If the second device <NUM> will not schedule the first device <NUM> for a while, the second device <NUM> transmits <NUM> a skipping command to the first device <NUM>. The skipping command indicates the first device <NUM> to skip monitoring the DL control channel for a skipping period.

In some example embodiments, the second device <NUM> may transmit the skipping command and the indication indicating the first device <NUM> transmits the RA request simultaneously. In some other example embodiments, the second device <NUM> may transmit the skipping command subsequent to the indication.

Upon reception of the skipping command, the first device <NUM> determines <NUM> whether there is an ongoing RA procedure. If the first device <NUM> determines that there is an ongoing RA procedure, the first device <NUM> stops the ongoing RA procedure, performs <NUM> the skipping command, and initiates <NUM> a new RA procedure upon expiration of the skipping period. On the other hand, if the first device <NUM> determines that there is no ongoing RA procedure, the first device <NUM> performs <NUM> the skipping command and initiates <NUM> an RA procedure upon expiration of the skipping period.

In the process <NUM>, the RA procedure is initiated by the second device <NUM> for handover, and may be a contention-based RA procedure.

The second device <NUM> transmits <NUM> to the first device <NUM> an indication indicating the first device <NUM> transmits a RA request to the second device <NUM>. In some example embodiments, the second device <NUM> may transmit the indication via a dedicated message on the DL control channel. For example, the second device <NUM> may transmit the indication via a handover command.

The first device <NUM> transmits <NUM> an RA request to the second device <NUM>. The second device <NUM> transmits <NUM> an RA response to the first device <NUM>. The first device <NUM> transmits <NUM> a scheduled transmission to the second device <NUM>.

Upon reception of the skipping command, the first device <NUM> determines <NUM> whether the skipping period overlaps with an RA time window. For example, in this example implementation, the first device <NUM> may determine whether the skipping period overlaps with a time window defined by RA contention resolution timer.

If the first device <NUM> determines that the skipping period entirely overlaps with the time window defined by RA contention resolution timer, the first device <NUM> may ignore <NUM> the skipping command. On the other hand, if the first device <NUM> determines that the skipping period partially overlaps with the time window defined by RA contention resolution timer, the first device <NUM> may perform <NUM> the skipping command until a start of the time window defined by RA contention resolution timer. Alternatively, if the first device <NUM> determines that the skipping period does not overlap with the time window defined by RA contention resolution timer, the first device <NUM> may perform <NUM> the skipping command.

Upon expiration of the skipping period, the first device <NUM> continues to monitor the DL control channel.

If the first device <NUM> is successful in the contention, the second device <NUM> may transmit <NUM> a contention resolution message to the first device <NUM>. The contention resolution message includes the C-RNTI of the first device <NUM>. In addition, if the second device <NUM> has DL data to be transmitted to the first device <NUM>, the contention resolution message may include DL scheduling information.

Alternatively, upon reception of the scheduled transmission, if the second device <NUM> has no DL data to be transmitted to the first device <NUM>, the second device <NUM> may not transmit the contention resolution message. Instead, the second device <NUM> may only transmit the skipping command. The skipping command comprises the C-RNTI of the first device <NUM> and indicates a successful contention resolution for the first device. For example, a payload of the skipping command may be scrambled with the C-RNTI of the first device <NUM>.

<FIG> shows a flowchart of an example method <NUM> implemented at a first device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method <NUM> will be described from the perspective of the first device <NUM> with reference to <FIG>. It would be appreciated that the method <NUM> may also be implemented at the second device <NUM> in <FIG>.

At block <NUM>, the first device <NUM> receives from a second device a command indicating the first device <NUM> to skip monitoring a downlink control channel between the second device and the first device <NUM> for a time period.

At block <NUM>, in response to the random access procedure being triggered by a first trigger condition, the first device <NUM> determines whether the time period overlaps with a time window associated with a random access procedure.

At block <NUM>, the first device <NUM> ignores or performs the command based on the determination.

In some example embodiments, ignoring or performing the command based on the determination comprises at least one of: in response to a determination that the time period entirely overlaps with the time window, ignoring the command; in response to a determination that the time period partially overlaps with the time window and a start of the time period is earlier than a start of the time window, performing the command until the start of the time window; in response to a determination that the time period partially overlaps with the time window and the start of the time window is identical to or earlier than the start of the time period, performing the command until an end of the time window; in response to a determination that the time period partially overlaps with the time window and the time window is within the time period, performing the command until the start of the time window and performing the command after the end of the time window; and in response to a determination that the time period fails to overlap with the time window, performing the command.

In some example embodiments, the time window is associated with one of a random access response and a contention resolution for the random access procedure.

In some example embodiments, the random access procedure is an ongoing random access procedure, and the time window corresponds to a whole random access procedure time of the ongoing RA procedure.

In some example embodiments, the first trigger condition comprises the first device <NUM> initiating the random access procedure as a contention-based random access.

In some example embodiments, the first trigger condition comprises the first device <NUM> initiating the random access procedure as a contention-free random access.

In the invention, the method <NUM> further comprises: in response to the random access procedure being triggered by a second trigger condition, perform the command.

In the invention, the second trigger condition comprises the first device <NUM> initiating the contention-free random access procedure for beam failure recovery.

In the invention, receiving the command comprises: receiving the command in a search space associated with the beam failure recovery, the command comprising a Cell Radio Network Temporary Identifier (C-RNTI) of the first device <NUM> and indicating a successful contention resolution for the first device <NUM>.

In some example embodiments, the second trigger condition comprises the second device initiating the random access procedure; and the method <NUM> further comprises receiving from the second device an indication indicating the first device <NUM> transmits a random access request to the second device.

In some example embodiments, receiving the command comprises: receiving a dedicated message on the downlink control channel, the dedicated message comprising the indication.

In some example embodiments, receiving the command comprises: receiving the command and the dedicated message simultaneously.

In some example embodiments, the method <NUM> further comprises upon expiration of the time period, transmit the random access request to the second device.

In some example embodiments, receiving the command comprises: receiving the command subsequent to the dedicated message.

In some example embodiments, the method <NUM> further comprises stopping the random access procedure; and upon expiration of the time period, initiating a further random access procedure.

In some example embodiments, the random access procedure comprises a contention-based random access; and receiving the indication comprises receiving a handover command comprising the indication.

In some example embodiments, receiving the command comprises: receiving the command subsequent to a scheduled transmission to the second device, the command comprising a Cell Radio Network Temporary Identifier of the first device <NUM>.

In some example embodiments, receiving the command comprises: receiving the command indicating a successful contention resolution for the first device <NUM>.

In some example embodiments, the method <NUM> further comprises upon expiration of the time period, monitor the downlink control channel.

<FIG> shows a flowchart of an example method <NUM> implemented at a second device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method <NUM> will be described from the perspective of the second device <NUM> with reference to <FIG>. It would be appreciated that the method <NUM> may also be implemented at the first device <NUM> in <FIG>.

At block <NUM>, the second device <NUM> transmits to a first device a command indicating the first device to skip monitoring a downlink control channel between the second device <NUM> and the first device for a time period. In response to the random access procedure being triggered by a first trigger condition, the command is ignored or performed by the first device based on a determination whether the time period overlaps with a time window associated with a random access procedure.

Optionally, at block <NUM>, the second device <NUM> schedules the first device upon expiration of the time period.

In some example embodiments, the command is ignored or performed by the first device based on a determination by at least one of: in response to a determination that the time period entirely overlaps with the time window, ignoring the command; in response to a determination that the time period partially overlaps with the time window and a start of the time period is earlier than a start of the time window, performing the command until the start of the time window; in response to a determination that the time period partially overlaps with the time window and the start of the time window is identical to or earlier than the start of the time period, performing the command until an end of the time window; in response to a determination that the time period partially overlaps with the time window and the time window is within the time period, performing the command until the start of the time window and performing the command after the end of the time window; and in response to a determination that the time period fails to overlap with the time window, performing the command.

In some example embodiments, the first trigger condition comprises the first device initiating the random access procedure as a contention-based random access.

In some example embodiments, the first trigger condition comprises the first device initiating the random access procedure as a contention-free random access.

In the invention, in response to the random access procedure being triggered by a second trigger condition, the command is performed.

In the invention, the second trigger condition comprises the first device initiating the contention-free random access procedure for beam failure recovery.

In the invention, transmitting the command comprises: transmitting the command in a search space associated with the beam failure recovery, the command comprising a Cell Radio Network Temporary Identifier (C-RNTI) of the first device and indicating a successful contention resolution for the first device.

In some example embodiments, the second trigger condition comprises the second device <NUM> initiating the random access procedure; and the method <NUM> further comprises: transmitting to the first device an indication indicating the first device transmits a random access request to the second device <NUM>.

In some example embodiments, transmitting the indication comprises: transmitting a dedicated message on the downlink control channel, the dedicated message comprising the indication.

In some example embodiments, transmitting the command comprises: transmitting the command and the dedicated message simultaneously.

In some example embodiments, the method <NUM> further comprises: upon expiration of the time period, receive the random access request from the first device.

In some example embodiments, transmitting the command comprises: transmitting the command subsequent to the dedicated message.

In some example embodiments, the random access procedure comprises a contention-based random access; and transmitting the indication comprises transmitting a handover command comprising the indication.

In some example embodiments, transmitting the command comprises: in response to reception of a scheduled transmission from the first device, transmitting the command comprising a Cell Radio Network Temporary Identifier of the first device.

In some example embodiments, transmitting the command comprises: transmitting the command indicating a successful contention resolution for the first device.

In some example embodiments, an apparatus capable of performing any of the method <NUM> (for example, the first device <NUM> or the second device <NUM>) may comprise means for performing the respective steps of the method <NUM>. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises means for receiving from a second device a command indicating the apparatus to skip monitoring a downlink control channel between the second device and the apparatus for a time period; and means for determining whether the time period overlaps with a time window associated with a random access procedure; and means for ignoring or performing the command based on the determination.

In some example embodiments, means for ignoring or performing the command based on the determination comprises means for at least one of: in response to a determination that the time period entirely overlaps with the time window, ignoring the command; in response to a determination that the time period partially overlaps with the time window and a start of the time period is earlier than a start of the time window, performing the command until the start of the time window; in response to a determination that the time period partially overlaps with the time window and the start of the time window is identical to or earlier than the start of the time period, performing the command until an end of the time window; in response to a determination that the time period partially overlaps with the time window and the time window is within the time period, performing the command until the start of the time window and performing the command after the end of the time window; and in response to a determination that the time period fails to overlap with the time window, performing the command.

In some example embodiments, the first trigger condition comprises the apparatus initiating the random access procedure as a contention-based random access.

In some example embodiments, the first trigger condition comprises the apparatus initiating the random access procedure as a contention-free random access.

In the invention, the apparatus further comprises in response to the random access procedure being triggered by a second trigger condition, means for performing the command.

In the invention, the second trigger condition comprises the apparatus initiating the random access procedure as a contention-free random access.

In some example embodiments, the second trigger condition comprises the apparatus initiating the contention-free random access procedure for beam failure recovery.

In the invention, means for receiving the command comprises:
means for receiving the command in a search space associated with the beam failure recovery, the command comprising a Cell Radio Network Temporary Identifier (C-RNTI) of the apparatus and indicating a successful contention resolution for the apparatus.

In some example embodiments, the second trigger condition comprises the second device initiating the random access procedure; and the apparatus further comprises means for receiving from the second device an indication indicating the apparatus transmits a random access request to the second device.

In some example embodiments, means for receiving the command comprises: means for receiving a dedicated message on the downlink control channel, the dedicated message comprising the indication.

In some example embodiments, means for receiving the command comprises: means for receiving the command and the dedicated message simultaneously.

In some example embodiments, the apparatus further comprises upon expiration of the time period, means for transmitting the random access request to the second device.

In some example embodiments, means for receiving the command comprises: means for receiving the command subsequent to the dedicated message.

In some example embodiments, the apparatus further comprises means for stopping the random access procedure; and upon expiration of the time period, means for initiating a further random access procedure.

In some example embodiments, the random access procedure comprises a contention-based random access; and means for receiving the indication comprises means for receiving a handover command comprising the indication.

In some example embodiments, means for receiving the command comprises: means for receiving the command subsequent to a scheduled transmission to the second device, the command comprising a Cell Radio Network Temporary Identifier of the apparatus.

In some example embodiments, means for receiving the command comprises: means for receiving the command indicating a successful contention resolution for the apparatus.

In some example embodiments, the apparatus further comprises upon expiration of the time period, means for monitoring the downlink control channel.

In some example embodiments, the apparatus comprises means for transmitting to a first device a command indicating the first device to skip monitoring a downlink control channel between the apparatus and the first device for a time period; wherein the command is ignored or performed by the first device based on a determination whether the time period overlaps with a time window associated with a random access procedure.

In the invention, the second trigger condition comprises the first device initiating the random access procedure as a contention-free random access procedure for beam failure recovery.

In the invention, means for transmitting the command comprises:
means for transmitting the command in a search space associated with the beam failure recovery, the command comprising a Cell Radio Network Temporary Identifier (C-RNTI) of the first device and indicating a successful contention resolution for the first device.

In some example embodiments, the second trigger condition comprises the apparatus initiating the random access procedure; and the apparatus further comprises:
means for transmitting to the first device an indication indicating the first device transmits a random access request to the apparatus.

In some example embodiments, means for transmitting the indication comprises: means for transmitting a dedicated message on the downlink control channel, the dedicated message comprising the indication.

In some example embodiments, means for transmitting the command comprises: means for transmitting the command and the dedicated message simultaneously.

In some example embodiments, the apparatus further comprises: upon expiration of the time period, means for receiving the random access request from the first device.

In some example embodiments, means for transmitting the command comprises: means for transmitting the command subsequent to the dedicated message.

In some example embodiments, the random access procedure comprises a contention-based random access; and means for transmitting the indication comprises means for transmitting a handover command comprising the indication.

In some example embodiments, means for transmitting the command comprises: in response to reception of a scheduled transmission from the first device, means for transmitting the command comprising a Cell Radio Network Temporary Identifier of the first device.

In some example embodiments, means for transmitting the command comprises: means for transmitting the command indicating a successful contention resolution for the first device.

<FIG> is a simplified block diagram of a device <NUM> that is suitable for implementing embodiments of the present disclosure. The device <NUM> may be provided to implement the communication device, for example the first device <NUM>, the first device <NUM> or the second device <NUM> as shown in <FIG>. As shown, the device <NUM> includes one or more processors <NUM>, one or more memories <NUM> coupled to the processor <NUM>, and one or more communication modules <NUM> coupled to the processor <NUM>.

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 methods <NUM> and <NUM> as described above with reference to <FIG> and <FIG>. 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.

Claim 1:
A first device, comprising:
means for receiving from a second device (<NUM>) a command indicating the first device (<NUM>) to skip monitoring a downlink control channel between the second device and the first device for a time period (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
means for, in response to a random access procedure being triggered by a first trigger condition,
determining whether the time period (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) overlaps with a time window (<NUM>) associated with the random access procedure, and
ignoring or performing the command based on the determination;
means for, in response to the random access procedure being triggered by a second trigger condition, performing the command, wherein the second trigger condition comprises the first device initiating the random access procedure as a contention-free random access procedure for beam failure recovery; and
means for receiving the command in a search space associated with the beam failure recovery, the command comprising a Cell Radio Network Temporary Identifier C-RNTI of the first device and indicating a successful contention resolution for the first device.