Patent Description:
The present disclosure relates generally to communication systems, and more particularly, to wireless communication including PDCCH monitoring.

<NUM>/NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. <NUM>/NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra reliable low latency communications (URLLC). Some aspects of <NUM>/NR may be based on the <NUM> Long Term Evolution (LTE) standard. There exists a need for further improvements in <NUM>/NR technology.

<CIT> relates to updated media access control (MAC) operations for semi-persistent scheduling (SPS) and discontinuous reception (DRX) operations with enhanced component carrier (eCC) secondary cells (SCells). For DRX operations, the DRX operations for the eCC SCell are defined with separate and independent timers from the DRX operations of the PCell.

The underlying problem of the present invention is solved by the subject matter of the independent claims.

When a user equipment (UE) is configured with carrier aggregation (CA), a secondary cell (SCell) may be configured with its own physical downlink control channel (PDCCH). In certain such examples, downlink control information (DCI) for downlink assignments and/or uplink grants on that SCell may be sent in its own PDCCH. These types of SCells may be referred to as "self-scheduling SCells.

In some examples, a UE may monitor PDCCH on a self-serving SCell until the self-serving SCell is deactivated. Since reactivating a deactivated SCell may incur delays, the network may keep an SCell active until the network determines that there is no more data to communicate in the near future. However, since it may be power expensive for a UE to monitor PDCCH continuously, it may be inefficient for the UE to monitor PDCCH while there is no or little traffic, for example, between data traffic bursts.

Techniques disclosed herein facilitate monitoring PDCCH when needed (e.g., when a traffic load is high). For example, disclosed techniques enable keeping a self-serving SCell active, but also enable a UE to stop monitoring PDCCH when there is a period of inactivity in traffic. By keeping the self-serving SCell active, techniques disclosed herein may enable reducing UE power consumption and may also enable avoiding latency incurred by re-activating the SCell.

As used herein, the term computer-readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, "computer-readable medium," "machine-readable medium," "computer-readable memory," and "machine-readable memory" may be used interchangeably.

The base stations <NUM> configured for <NUM> LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC <NUM> through backhaul links <NUM> (e.g., S1 interface). The base stations <NUM> configured for <NUM>/NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network <NUM> through backhaul links <NUM>. The base stations <NUM> may communicate directly or indirectly (e.g., through the EPC <NUM> or core network <NUM>) with each other over backhaul links <NUM> (e.g., X2 interface).

The base station <NUM> and the UE <NUM> may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate beamforming.

Referring again to <FIG>, in certain aspects, the UE <NUM> may be configured to manage one or more aspects of wireless communication via PDCCH monitoring in carrier aggregation. For example, UE <NUM> may include a PDCCH monitoring component <NUM> configured to stop the PDCCH monitoring on a set of activated secondary cells (SCells) in response to a monitoring stoppage event, and resume the PDCCH monitoring on at least one SCell of the set of activated SCells in response to a monitoring resumption event. In an aspect, the set of activated SCells may remain activated during a period between the stopping of the PDCCH monitoring and the resuming of the PDCCH monitoring. As used herein, an activated SCell may be an SCell that is kept active by the network. For example, since reactivating a deactivated SCell may incur delays (sometimes significant delays), the network may keep an SCell active until the network determines that there is no more data to communicate in the near future.

Although the following description provides examples related to <NUM>/NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and/or other wireless technologies, in which a UE monitoring PDCCH on a self-serving SCell may incur power consumption costs and/or in which deactivating and activating of PDCCH monitoring on a self-scheduling SCell may incur long latency costs.

Furthermore, although the following description may be focused on monitoring PDCCH on self-scheduling SCells, the concepts described herein may additionally or alternatively be applicable to other component carriers, other cells, and/or other channels in a carrier aggregation context.

<FIG> provide an example of slot configuration <NUM> with <NUM> symbols per slot and numerology µ=<NUM> with <NUM> slots per subframe. The slot duration is <NUM>, the subcarrier spacing is <NUM> and the symbol duration is approximately <NUM> µs.

At least one of the TX processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM> may be configured to perform aspects in connection with the PDCCH monitoring component <NUM> of <FIG>.

When a user equipment (UE) is configured with carrier aggregation (CA), some secondary cells (SCells) may be configured with their own physical downlink control channel (PDCCH). In some such examples, downlink control information (DCI) for downlink assignments and/or uplink grants on those SCells may be sent in their own PDCCH. These types of SCells may be referred to as "self-scheduling SCells.

In some examples, a UE may monitor PDCCH on a self-scheduling SCell until the self-scheduling SCell is deactivated. In some examples, an SCell may be de-activated by, for example, signaling (e.g., an SCell de-activation MAC CE) or a timer (e.g., expiration of an SCell de-activation timer). Since reactivating a deactivated SCell may incur delays (sometimes significant delays), the network may keep an SCell active until the network determines that there is no more data to communicate in the near future. However, since it may be power intensive for a UE to monitor PDCCH continuously, it may be inefficient for the UE to monitor PDCCH while there is no or little traffic, for example, between data traffic bursts. Furthermore, in some examples, deactivating and reactivating of the SCell may prompt radio resource control (RRC) reconfiguration of the PDCCH configuration (e.g., by re-designing a search space, configuring a control resource set (CORESET), etc.), which may introduce additional latency and/or that may reduce any power savings that may be experienced by deactivating the SCell.

In an aspect, with respect to possible discontinuation reception (DRX) procedures, when an DRX inactivity timer (DIT) expires, a UE <NUM> may enter a DRX OFF time. Additionally, or in the alternative, the UE <NUM> may enter the DRX OFF time before the DIT expires when the UE <NUM> receives a DRX MAC CE. In such an aspect, in the context of a CA configuration, all the cells may have the same DRX configuration and follow the same DRX ON/OFF configuration. But such procedures may introduce inefficiencies. For example, where a UE is configured with two carriers, the second carrier may have higher throughput as well as higher power consumption than the first carrier. Hence the second carrier may be used for offloading large data bursts. In such as aspect, once bursts are served, it may not be power efficient to still keep both the second carrier and the first carrier active. In another example, even within a data burst, traffic loads may vary. After a traffic load reduces, an efficient procedure would allow for the network to stop PDCCH monitoring on some serving cells (e.g. SCells) to reduce power consumption.

Techniques disclosed herein facilitate efficient monitoring PDCCH (e.g., when a traffic load is high). For example, disclosed techniques enable keeping a self-scheduling SCell active, but also enable a UE to stop monitoring PDCCH on the self-scheduling SCell when there is a period of inactivity in traffic. By keeping the self-scheduling SCell active, techniques disclosed herein may enable reducing UE power consumption and may also enable avoiding latency incurred by re-activating the SCell. Thus, it may be appreciated that techniques disclosed herein provide a low-latency technique for a UE to stop and restart monitoring PDCCH on a self-scheduling SCell.

<FIG> illustrates an example of wireless communication <NUM> between a base station <NUM>, a UE <NUM>, and an SCell <NUM>, as presented herein. In the illustrated example, the SCell <NUM> is a self-scheduling SCell. One or more aspects of the base station <NUM> maybe implemented by the base station <NUM> of <FIG> and/or the base station <NUM> of <FIG>. One or more aspects of the UE <NUM> may be implemented by the UE <NUM> of <FIG> and/or the UE <NUM> of <FIG>. In the illustrated example of <FIG> (and as disclosed herein), the UE <NUM> may stop PDCCH monitoring on the SCell <NUM> when overall traffic load is low, and may resume PDCCH monitoring on the SCell <NUM> when traffic resumes.

While the wireless communication <NUM> includes one base station <NUM> and one SCell <NUM> in communication with the UE <NUM>, in additional or alternative examples, the UE <NUM> may be in communication with any suitable quantity of base stations and/or SCells. For example, the UE <NUM> may be in communication with zero, one, two, or more base stations and/or the UE <NUM> may be in communication with zero, one, two, or more SCells (sometimes referred to as a set of SCells). Furthermore, while the wireless communication <NUM> indicates that the UE <NUM> stops and resumes PDCCH monitoring on the SCell <NUM>, in additional or alternative examples, the UE <NUM> may stop PDCCH monitoring on a first SCell (e.g., the SCell <NUM>) based on the occurrence of a - stoppage event. In some examples, the event may include reception of signaling from a base station. The UE may start (or resume) PDCCH monitoring on a second SCell (e.g., the SCell <NUM> and/or one or more additional SCells) based on the occurrence of a monitoring resumption event. In some examples, the event may include reception of signaling from a base station.

The UE <NUM> may receive a communication <NUM> from the base station <NUM> configuring the UE <NUM> with the SCell <NUM> and activating the SCell <NUM>. In some examples, the base station <NUM> may add the SCell <NUM> to a primary cell (PCell) and/or to a set of SCells via an RRC connection reconfiguration procedure. The UE <NUM> may then begin monitoring PDCCH <NUM> on the SCell <NUM>. The UE <NUM> may detect, at <NUM>, low overall traffic on the SCell <NUM>, and stop monitoring PDCCH on the SCell <NUM>, at <NUM>. In some examples, and as described below, the UE <NUM> may detect the low overall traffic based on, for example, a timer, network signaling, and/or occurrence of a predefined event. The UE <NUM> may then detect, at <NUM>, that traffic resumed, and resume monitoring PDCCH on the SCell <NUM>, at <NUM>. In some examples, and as described below, the UE <NUM> may detect that traffic resumed based on, for example, network signaling and/or occurrence of a predefined event.

In some examples, the UE <NUM> may stop PDCCH monitoring on the SCell <NUM> based on a timer. For example, the UE <NUM> may include an SCell inactivity timer (SIT) that is started or restarted by transmission or reception of data on the SCell <NUM>. In some such examples, the UE <NUM> may stop monitoring PDCCH on the SCell <NUM> in response to the SCell inactivity timer expiring. In some examples, the UE <NUM> may retain the current (or active) bandwidth part (BWP) associated with the SCell, but may stop monitoring PDCCH on that SCell. In some examples, the UE <NUM> may switch from an active BWP to a different BWP that does not contain PDCCH. In certain such examples, the UE <NUM> may autonomously switch from the active BWP to the different BWP. For example, the UE <NUM> may switch form the active BWP to the different BWP without receiving signaling (e.g., from the base station <NUM> and/or the SCell <NUM>).

In some examples, the UE <NUM> may stop PDCCH monitoring on the SCell <NUM> based on a signal received from the network. For example, the UE <NUM> may receive downlink control information (DCI) from the base station <NUM>. In some examples, the DCI received from the base station <NUM> may be similar to DCI used for de-activating a type-<NUM> uplink configured grant and/or may be similar to DCI used for de-activating type-<NUM> downlink semi-persistent scheduling (SPS). In some examples, the DCI received from the base station <NUM> may be scheduling DCI that may cause the UE <NUM> to switch from an active BWP to a different BWP (e.g., perform a BWP switch) that does not contain PDCCH.

In some examples, the signal (or signaling) received from the network may be a medium access control control element (MAC-CE). In some such examples, the MAC-CE may indicate a particular SCell and/or a set of SCells that the UE <NUM> is to stop PDCCH monitoring. In such an aspect, UE <NUM> may suspend PDCCH monitoring on a SCell until further notice to resume monitoring.

In some examples, the occurrence of a predefined event may trigger the UE <NUM> to stop PDCCH monitoring on the SCell <NUM>. For example, the UE <NUM> may be configured with connected mode discontinuous reception (C-DRX). In some such examples, the base station <NUM> may configure the UE <NUM> with C-DRX parameters. For example, the C-DRX parameters may include a set of SCells for which the UE is to perform PDCCH monitoring. In some such examples, the C-DRX parameters may additionally or alternatively identify a subset of SCells of the set of SCells for which the UE <NUM> is to stop PDCCH monitoring at the start of a C-DRX ON duration. In an aspect, a DRX MAC CE may prompt the UE <NUM> to resume monitoring at a subsequent (e.g., next) ON duration. In another aspect, a DRX MAC CE may provide the UE <NUM> with a duration for which to suspend PDCCH monitoring. In such an aspect, the duration may be provided as a number of DRX cycles. Further, in such an aspect, if short DRX cycles are configured, the UE <NUM> may alternate between short and long DRX cycles depend on traffic patterns. As such, defining the duration in number of DRX cycles, instead of specifically short DRX cycles or specifically long DRX cycles, may simplify signaling. The subset of SCells may include any suitable quantity of SCells of the set of SCells including, for example, zero SCells of the set of SCells to all of the SCells of the set of SCells. It some examples, the subset of SCells may include a quantity of SCells and/or may include identifiers for particular SCells (e.g., of the set of SCells).

Thus, as described above, in some examples, the UE <NUM> may stop PDCCH monitoring on the SCell <NUM> while keeping the SCell active (e.g., without de-activating the SCell <NUM>).

In some examples, and as described above at <NUM>, the UE <NUM> may resume PDCCH monitoring on the SCell. For example, the UE <NUM> may resume PDCCH monitoring on a first SCell (e.g., the SCell <NUM>). In other examples, the UE <NUM> may additionally or alternatively resume (or start) PDCCH monitoring on a second SCell different than the first SCell, may resume (or start) PDCCH monitoring on a set of SCells including the first SCell, and/or may resume (or start) PDCCH monitoring on a set of SCells that does not include the first SCell. The UE <NUM> may resume (or start) PDCCH monitoring on the SCell based on network signaling and/or an occurrence of a predefined event.

In some examples, the UE <NUM> may resume PDCCH monitoring on the SCell <NUM> (at <NUM>) based on network signaling received from the network. For example, the UE <NUM> may receive DCI from the base station <NUM>. In some examples, the UE <NUM> may be capable of cross-carrier signaling that enables the UE <NUM> to connect to different cells to receive PDCCH on different carriers. In some such examples, the DCI received from the base station <NUM> may be received via a fallback cell for which the UE <NUM> is still performing PDCCH monitoring. For example, after the UE <NUM> stops PDCCH monitoring on a first SCell (e.g., at <NUM>), the UE <NUM> may receive DCI for the first SCell from the fallback cell. In some examples, the fallback cell may be a designated (or pre-configured) SCell that the UE <NUM> is monitoring. In some examples, the fallback cell may be a primary cell (PCell).

In some examples, the DCI received from base station <NUM> may be similar to DCI used for activating a type-<NUM> uplink configured grant and/or may be similar to DCI used for activating type-<NUM> downlink semi-persistent scheduling (SPS). In some examples, the DCI received from the base station <NUM> may be scheduling DCI that may cause the UE <NUM> to switch from an active BWP to a different BWP (e.g., perform a BWP switch) that contains PDCCH.

In some examples, the signal received from the network may be a MAC CE. In some such examples, the MAC CE may indicate a particular SCell and/or a set of SCells for which the UE <NUM> is to resume (or start) PDCCH monitoring.

In some examples, the signal received from the network may be a wakeup signal (WUS). For example, the UE <NUM> may be configured with connected mode discontinuous reception (C-DRX) and the base station <NUM> may configure the UE <NUM> with C-DRX parameters including a set of SCells. In some such examples, the base station <NUM> may transmit a WUS to the UE <NUM> (e.g., at the start of a C-DRX ON duration) indicating a subset of SCells of the set of SCells for which the UE <NUM> is to resume (or start) PDCCH monitoring.

In some examples, the occurrence of a predefined event may trigger the UE <NUM> to resume PDCCH monitoring on an SCell. In some such examples, the predefined event may be associated with C-DRX states. For example, when a C-DRX inactivity timer is started or restarted (e.g., upon receipt of PDCCH for transmission of data or receipt of data), the UE <NUM> may resume (or start) PDCCH monitoring on a subset of SCells of the set of SCells. In some such examples, the base station <NUM> may configure the UE <NUM> with C-DRX parameters including the subset of SCells of the set of SCells to monitor during respective C-DRX states.

In some examples, the subset of SCells (e.g., of the WUS and/or the C-DRX parameters) may include any suitable quantity of SCells of the set of SCells including, for example, zero SCells of the set of SCells to all of the SCells of the set of SCells. In some examples, the subset of SCells may include a quantity of SCells and/or may include identifiers for particular SCells (e.g., of the set of SCells).

In some examples, the UE <NUM> may resume (or start) PDCCH monitoring on an SCell based on DCI and a linkage (e.g., an implied linkage) between a search space of a PCell and a set of SCells. For example, the network may designate a search space associated with a PCell and also link a set of SCells to the designated search space. In some such examples, scheduling DCI received in the designated search space may cause the UE <NUM> to resume PDCCH monitoring on the linked set of SCells.

As an illustrative example, consider an example in which the UE receives DCI in a first search space on a PCell on PDCCH and that the first search space is linked to a first SCell. It may be appreciated that the UE has at least one search space in a PDCCH. In some such examples, if the UE receives scheduling DCI in the first search space on the PCell, then the UE may resume monitoring PDCCH on the first SCell. In some examples, if the UE has previously stopped monitoring PDCCH on the first SCell (e.g., in response to a monitoring stoppage event), then the UE may continue not monitoring PDCCH on the first SCell as long as the UE does not receive DCI in the first search space on the PCell. In some examples, the event maybe based on an indication or signal received from the base station. In some examples, the linkage between the search space and the SCell may be a many-to-one linkage. For example, a set of SCells may be linked to a same search space on a PCell. The set of SCells may include any appropriate quantity of SCells, including, for example, one SCell, two SCells, etc..

Thus, as described above, in some examples, the UE <NUM> may resume PDCCH monitoring on an SCell after stopping the PDCCH monitoring on the SCell. In some such examples, because the SCell is still active when the UE <NUM> stops the PDCCH monitoring on the SCell, the UE <NUM> may resume the PDCCH monitoring relatively quickly (e.g., as compared to performing an RRC connection reconfiguration procedure to activate the SCell). Thus, the techniques disclosed herein facilitate low-latency (e.g., relatively fast) stopping and resuming of PDCCH monitoring of one or more SCells.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a UE or a component of a UE (e.g., the UE <NUM> of <FIG>, the UE <NUM> of <FIG>, the UE <NUM> of <FIG>, the apparatus <NUM>/<NUM>' of <FIG> and <FIG>, respectively, the processing system <NUM>, which may include the memory <NUM> of <FIG>, and which may be the entire UE <NUM>, or a component of the UE <NUM>, such as the TX processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>). The method may enable a UE or other wireless device to reduce power consumption during PDCCH monitoring and/or perform stopping and resuming of PDDCH monitoring. Optional aspects are illustrated with a dashed line.

At <NUM>, the UE may monitor a PDCCH on an activated SCell, as described in connection with, for example, monitoring PDCCH <NUM> on the SCell <NUM> of <FIG>. For example, a traffic monitoring component <NUM> may facilitate the monitoring of PDCCH on an SCell. The activated SCell may be an SCell associated with a base station which is configured to be able to be in communication with the UE. <FIG> illustrates the example UE <NUM> monitoring PDCCH <NUM> on the SCell <NUM>.

At <NUM>, the UE may receive a MAC-CE that indicates at least one SCell of a set of activated SCells for which to stop monitoring PDCCH. In an aspect, the MAC CE may be received from a PCell, an SCell, or both. In an aspect, the MAC CE may indicate to stop monitoring until an explicit instruction is received to resume monitoring. <FIG> illustrates the example UE <NUM> configured to monitor for reception of a MAC CE from PCell <NUM> and/or SCell <NUM>.

At <NUM>, the UE may trigger a monitoring stoppage event. As described above in connection with the wireless communication <NUM> of <FIG>, the monitoring stoppage event may be triggered, for example, via a timer (e.g., an SCell inactivity timer) expiring, via network signaling (e.g., via received DCI and/or via a received MAC CE), and/or via the occurrence of a predefined event (e.g., the start of a C-DRX ON duration). In an aspect where a MAC CE is received, the MAC CE may indicate a stop monitoring time duration. In such an aspect, where the UE is configured with C-DRX, and the stop monitoring duration may be based on a number of DRX cycles. Further, in such an aspect, the DRX cycles may be any combination and/or order of long DRX cycles and short DRX cycles. In another aspect, the stoppage event may occur where a data traffic load fails to satisfy a minimum traffic threshold. In such aspect, the data traffic load may refer to a data traffic load associated with the cell and/or a total data traffic load across the cells associated with the UE.

At <NUM>, the UE stops the PDCCH monitoring on at least one SCell of the set of activated SCells in response to the monitoring stoppage event. In some examples, the UE stops the PDCCH monitoring on the SCell while the SCell remains active (e.g., an activated SCell). As illustrated at <NUM> in <FIG>, the UE may stop the PDCCH monitoring on the SCell. By stopping PDCCH monitoring on an SCell after the monitoring stoppage event is triggered, the UE may conserve power by not continuously monitoring PDCCH on the SCell.

At <NUM>, the UE may receive a MAC CE that indicates at least one SCell of a set of activated SCells for which to resume monitoring PDCCH. In an aspect, the MAC CE may be received from a PCell, a monitored SCell, or both. <FIG> illustrates the example UE <NUM> configured to monitor for reception of a MAC CE from PCell <NUM> and/or SCell <NUM>.

At <NUM>, the UE may trigger a monitoring resumption event. As described above in connection with the wireless communication <NUM> of <FIG>, the monitoring resumption event may be triggered, for example, via network signaling (e.g., via received DCI, via a received wakeup signal, via a received MAC CE, and/or via a received scheduling DCI) and/or via the an event occurrence (e.g., via the starting or restarting of a C-DRX inactivity timer).

At <NUM>, the UE resumes the PDCCH monitoring on at least one SCell of the set of activated SCells in response to the monitoring resumption event. In some examples, the UE resumes the PDCCH monitoring on the SCell while the SCell remains active (e.g., activated SCell). Thus, the UE may incur minimal latency costs compared to waiting to re-activate the SCell before resuming PDCCH monitoring on the SCell. As illustrated at <NUM> in <FIG>, the UE may resume the PDCCH monitoring on the SCell.

In some examples, the SCell remains active during a period between the stopping of the PDCCH monitoring and the resuming of the PDCCH monitoring. For example, the UE may stop the PDCCH monitoring on the SCell at a first time, and the UE may resume the PDCCH monitoring on the SCell at a second time. In certain such examples, the SCell may remain active during the time between the first time and the second time.

By keeping the SCell active between the first time and the second time, the UE is able to reduce latency associated with transitioning from not performing PDCCH monitoring on the SCell to performing PDCCH monitoring on the SCell. Furthermore, by stopping the PDCCH monitoring on the SCell during, for example, periods of relatively low data traffic loads, the UE is able to conserve power.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM>. The apparatus may be a UE or a component of a UE. The apparatus includes a reception component <NUM> that receives downlink communication from a base station and/or an SCell. For example, the reception component <NUM> may be configured to receive PDCCH, PDSCH, a wakeup signal, a MAC-CE, and/or DCI from a base station <NUM> and/or an SCell <NUM>. The apparatus includes a transmission component <NUM> configured to transmit uplink communication to, for example, the base station <NUM> and/or the SCell <NUM>.

The apparatus may include a traffic monitoring component <NUM> configured to determine whether a data traffic load on the SCell satisfies a minimum traffic threshold (e.g., as described in connection with <NUM> of <FIG>). In some examples, the traffic monitoring component <NUM> may trigger the monitoring stoppage event based on the determination (e.g., as described in connection with <NUM> of <FIG>).

The apparatus may include the traffic monitoring component <NUM> configured to determine whether a data traffic load on the SCell is greater than a traffic threshold (e.g., as described in connection with <NUM> and/or <NUM> of <FIG>). In some examples, the traffic monitoring component <NUM> may trigger the monitoring resumption event based on the determination (e.g., as described in connection with <NUM> of <FIG>).

The apparatus may include a timer component <NUM> configured to start or restart a timer (e.g., an SCell inactivity timer) in response to transmission of subsequent (or new) PUSCH and/or in response to reception of subsequent (or new) PDSCH on the SCell. In some examples, the timer component <NUM> may trigger the monitoring stoppage event when the timer expires.

The apparatus may include a DCI handling component <NUM> configured to receive DCI from a base station. In some examples, the base station may be associated with the SCell. In some examples, the DCI handling component <NUM> may trigger the monitoring stoppage event in response to the received DCI.

The apparatus may include the DCI handling component <NUM> configured to receive DCI from a fallback cell that the apparatus is monitoring. In some examples the DCI handling component <NUM> may trigger the monitoring resumption event in response to the received DCI.

The apparatus may include the DCI handling component <NUM> configured to receive scheduling DCI on a search space of a PCell. In some examples, the search space is linked to one or more SCells. In some examples the DCI handling component <NUM> may trigger the monitoring resumption event in response to the received scheduling DCI. In some examples, the apparatus resumes PDCCH monitoring on the one or more SCells linked to the search space. In some examples, the apparatus resumes the PDCCH monitoring based on instructions in the received scheduling DCI.

The apparatus may include a MAC CE handling component <NUM> configured to receive a MAC CE via a base station. In some examples, the base station may be associated with the SCell. In some examples the MAC CE may indicate one or more SCells for the apparatus to stop PDCCH monitoring. In some examples the MAC CE handling component <NUM> may trigger the monitoring stoppage event in response to the received MAC CE.

The apparatus may include the MAC CE handling component <NUM> configured to receive a MAC CE via a base station. In some examples, the base station may be associated with the SCell. In some examples, the MAC CE handling component <NUM> may trigger the monitoring resumption event in response to the received MAC CE.

The apparatus may include a C-DRX handling component <NUM> configured to detect the occurrence of a predefined event, such as the start of a C-DRX cycle. In some examples, the C-DRX handling component <NUM> may trigger the monitoring stoppage event in response to the occurrence of the predefined event.

The apparatus may include the C-DRX handling component <NUM> configured to receive a wakeup signal identifying one or more SCells. In some examples, the C-DRX handling component <NUM> may trigger the monitoring resumption event in response to the received wakeup signal.

The apparatus may include the C-DRX handling component <NUM> configured to detect the occurrence of a predefined event, such as the start of a C-DRX inactivity timer or a restart of the C-DRX inactivity timer. In some examples, the C-DRX handling component <NUM> may trigger the monitoring resumption event in response to the occurrence of the predefined event.

The apparatus may include a stop monitoring component <NUM> configured to stop PDCCH monitoring on one or more SCells in response to a monitoring stoppage event (e.g., as described in connection with <NUM> of <FIG>). In some examples, the stop monitoring component <NUM> may stop the PDCCH monitoring on the one or more SCells while maintaining the active BWP. In some examples, the stop monitoring component <NUM> may stop the PDCCH monitoring on the one or more SCells by switching from an active BWP to a different BWP that does not include a PDCCH. In some examples the stop monitoring component <NUM> may stop the PDCCH monitoring on the one or more SCells by switching from an active BWP to a different BWP that does not include a PDCCH based on instructions in received DCI.

The apparatus may include a resume monitoring component <NUM> configured to resume PDCCH monitoring on one or more SCells in response to a monitoring resumption event (e.g., as described in connection with <NUM> of <FIG>). In some examples the resume monitoring component <NUM> may resume the PDCCH monitoring on the one or more SCells by switching from an active BWP to a different BWP that includes a PDCCH based on instructions in received DCI.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. Alternatively, the processing system <NUM> may be the entire UE (e.g., see <NUM> of <FIG>).

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication includes means for stopping a physical downlink control channel (PDCCH) monitoring on a set of secondary cells (SCells) in response to a monitoring stoppage event; means for resuming the PDCCH monitoring on at least one SCell of the set of activated SCells in response to a monitoring resumption event, wherein the set of activated SCells remain active during a period between the stopping of the PDCCH monitoring and the resuming of the PDCCH monitoring; means for receiving a first medium access control (MAC) control element (CE) via a base station, wherein the first MAC CE indicates at least one SCell of the set of activated SCells to stop monitoring; means for triggering the monitoring stoppage event for the at least one SCell of the set of activated SCells in response to the received first MAC CE; means for receiving a second MAC CE via the base station, wherein the second MAC CE indicates at least one SCell of the set of activated SCells that the UE is to resume PDCCH monitoring; means for triggering the monitoring resumption event in response to the received second MAC-CE; means for triggering the monitoring resumption event upon detection of a subsequent ON duration in the C-DRX; means for triggering the monitoring resumption event upon expiration of the stop monitoring time duration; triggering the monitoring stoppage event upon determining that a data traffic load fails to satisfy a minimum traffic threshold; and triggering the monitoring resumption event when a data traffic load on the SCell satisfies a traffic threshold.

Techniques disclosed herein facilitate monitoring PDCCH when needed (e.g., when a traffic load is high). For example, disclosed techniques enable keeping a self-serving SCell active, but also enable a UE to stop monitoring PDCCH on the self-serving SCell when there is a period of inactivity in traffic. By keeping the self-serving SCell active, techniques disclosed herein may enable reducing UE power consumption and may also enable avoiding latency incurred by reactivating the SCell. Thus, techniques disclosed herein provide a technique for a UE to stop and restart monitoring PDCCH on a self-serving SCell.

Claim 1:
A method (<NUM>) of wireless communication at a user equipment, UE (<NUM>), comprising:
stopping (<NUM>) a physical downlink control channel, PDCCH, monitoring on a set of activated secondary cells, SCells, in response to a monitoring stoppage event triggered via a received first medium access control, MAC, control element, CE, from a base station (<NUM>); and
resuming (<NUM>) the PDCCH monitoring on at least one SCell of the set of activated SCells in response to a monitoring resumption event, wherein the set of activated SCells remain activated during a period between the stopping of the PDCCH monitoring and the resuming of the PDCCH monitoring.