Patent Description:
This background description is for the purpose of generally presenting the context of the disclosure.

Some wireless communication networks allow compatible devices to share an unlicensed carrier with other radio access technologies. In such cases, to fairly allocate the shared medium, devices operating in the unlicensed carrier typically need to perform channel access procedures before transmitting messages. In particular, a device may need to listen for other communications (i.e., detect energy) on the unlicensed carrier before using the carrier to transmit information, thereby reducing or eliminating interference with the communications of other networks/devices.

The 3rd Generation Partnership Project (3GPP) specification for fifth-generation (<NUM>) new radio ("NR") networks, and specifically 3GPP TS <NUM> v16. <NUM> (addressing the use of unlicensed carriers for <NUM> NR devices under what is commonly referred to as the "NR-U" study item), attempts to maintain fair co-existence with other radio access technologies such as WiFi® (IEEE <NUM>) by requiring that <NUM> NR devices perform a "listen-before-talk" (LBT) channel access procedure before transmitting via the unlicensed carrier. This restriction on usage of the unlicensed carrier can be problematic for communications that would otherwise be synchronized or tightly scheduled. In NR-U, for example, a base station (e.g., a gNB) must perform a successful LBT procedure to establish a channel occupancy time (COT) before using the unlicensed carrier to send physical downlink control channel (PDCCH) information to a user device (commonly referred to using the acronym "UE" for "user equipment"). Thus, the user device does not know a priori when the base station might send control channel information, and does not know when to monitor the PDCCH. Continuous or nearly continuous monitoring of the PDCCH is not a satisfactory solution, as this would greatly increase power consumption at the user device.

According to one proposal, the user device would monitor the PDCCH at a relatively high rate until the user device receives a signal from the base station indicating that the base station has established a COT. Shortly thereafter, the user device begins monitoring the PDCCH at a relatively low rate. While this approach provides the base station more opportunities to begin transmitting control channel information via the PDCCH, and can also reduce power consumption in the user device, problems still arise because the user device may fail to receive the signal indicating the start of the COT. Thus, the base station may not know whether the user device has shifted to a different PDCCH monitoring pattern.

3GPP R1-<NUM> summarizes a number of proposals for dynamic PDCCH monitoring.

3GPP R1-<NUM> discusses various aspects of PDSCH and PDCCH design. This document proposes to support dynamic indication of a change in the UE configured PDCCH monitoring occasions within a gNB acquired COT.

3GPP R1-<NUM> discusses potential DL reference signals and physical layer channels design for NR-U, including dynamic PDCCH monitoring, COT structure indication, PDSCH transmission and a mechanism to detect DL starting point.

3GPP R1-<NUM> generally relates to the design of signal/channel for COT structure indication and design of CSI-RS and PDSCH time domain mapping.

The aspects of the present invention are defined in the appended independent claims. Particular realizations of the invention are defined in the appended dependent claims.

A base station of this disclosure (e.g., a gNB) communicates with a user device via a shared carrier, and uses a channel access procedure (e.g., LBT) to gain access to the shared carrier. The base station configures the user device to monitor a control channel (e.g., a PDCCH) according to one pattern of control channel occasions (the "pre-transmission pattern") before a transmission time (e.g., a COT) begins for the base station, and according to a different pattern of control channel occasions (the "transmission pattern") when the transmission time is underway.

The pre-transmission and transmission patterns, while different, include at least one overlapping control channel occasion. For example, the pre-transmission pattern may include control channel occasions at the start and mid-point of each time unit, while the transmission pattern may only include a single control channel occasion at the start of each time unit. By virtue of the overlapping occasion(s), the base station is aware of at least one occasion per time unit in which the user device should be monitoring the control channel, regardless of whether the user device has yet received from the base station a signal indicating the transmission time has started, a signal indicating the transmission time has ended, or a signal indicating a switch from the pre-transmission pattern to the transmission pattern, and regardless of whether the user device has yet switched from the pre-transmission pattern to the transmission pattern or vice versa. Thus, for example, the base station may reliably know when to transmit the signal that informs the user device of the transmission time, and also, in some implementations, when to re-transmit the signal to the user device (to increase the likelihood that the user device will learn that the transmission time is underway).

In various implementations, the base station may send the user device a wake-up signal (WUS), a signal indicating that the transmission time has started, or a signal indicating the structure of the transmission time (e.g., a COT duration), to inform the user device of the transmission time and trigger the change to the transmission pattern of control channel occasions. In some implementations where the base station re-transmits the signal one or more times to ensure reception by the user device, the base station updates the transmission time information in the signal with each re-transmission. For example, the initial transmission of a signal may indicate the full duration of a COT, while a re-transmission of the signal may instead indicate the amount of time that remains in the COT when the retransmission occurs.

In some implementations, the base station configures the user device (e.g., via one or more radio resource control (RRC) messages, one or more medium access control (MAC) control elements, one or more downlink control information (DCI), etc.) to monitor the control channel according to two different patterns of control channel occasions, and the user device selectively executes the pre-transmission pattern or the transmission pattern by combining the occasions of the two patterns in different ways. For example, the user device may execute the pre-transmission pattern by monitoring the control channel during all occasions of a first pattern and all occasions of a second pattern, and then change to the transmission pattern by monitoring the control channel only during the occasions of the first pattern and not the second pattern. As another example, the user device may execute the pre-transmission pattern by monitoring the control channel during all occasions of the first pattern, and then change to the transmission pattern by monitoring the control channel only during those occasions of the first and second pattern that overlap each other. As a further example, the user device may execute the pre-transmission pattern by monitoring the control channel only during occasions of the first pattern, and then change to the transmission pattern by monitoring the control channel during all occasions of the first pattern and all occasions of the second pattern.

In some implementations, the base station configures the user device to use different time-frequency resources when monitoring the control channel during the occasions of different patterns. In the above examples, for instance, the base station may configure the user device to use a first time-frequency resource (e.g., a first search space configuration) when monitoring during occasions of the first pattern, and a second, different time-frequency resource (e.g., a second search space configuration) when monitoring during occasions of the second pattern. Additionally or alternatively, in some implementations, and to increase the granularity with which the base station can send control channel information, the base station sends the user device a wake-up signal to cause the user device to monitor the control channel on a single, additional occasion that does not overlap any occasions of the first or second pattern.

According to claim <NUM>, one aspect of these techniques is a method of obtaining control channel information from a base station that communicates with a user device via a shared carrier. The method can be implemented in the user device using processing hardware and comprises monitoring a control channel on the shared carrier according to a pre-transmission pattern of control channel occasions; while monitoring the control channel using the pre-transmission pattern, receiving, from the base station via the shared carrier, a signal indicating a transmission time during which the shared carrier is available to the base station; and in response to receiving the signal, monitoring, during the transmission time, the control channel on the shared carrier according to a transmission pattern of control channel occasions that is different than the pre-transmission pattern but includes at least one control channel occasion that overlaps a control channel occasion of the pre-transmission pattern.

According to independent claim <NUM>, another aspect of these techniques is a user device comprising processing hardware and configured to execute the method above.

According to independent claim <NUM>, another aspect of these techniques is a method of providing control channel information to a user device that communicates with a base station via a shared carrier. The method can be implemented in the base station using processing hardware and comprises determining, using a channel access procedure, that the shared carrier is available to the base station for a transmission time; causing, at least by transmitting one or more messages to the user device via the shared carrier, the user device to monitor a control channel on the shared carrier according to a pre-transmission pattern of control channel occasions before the transmission time, and monitor the control channel on the shared carrier according to a transmission pattern of control channel occasions during the transmission time. The transmission pattern is different than the pre-transmission pattern but includes at least one control channel occasion that overlaps a control channel occasion of the pre-transmission pattern.

According to independent claim <NUM>, another aspect of these techniques is a base station comprising processing hardware and configured to execute the method above.

Using the techniques of this disclosure, a communication device such as a UE monitors a control channel on a shared carrier in a manner that reduces power consumption at the UE, and/or reduces the delay in starting a transmission (e.g., an uplink transmission that requires configuration of the UE via the control channel). As the term is used herein, a "carrier" may be any type of frequency spectrum or band, which corresponds to at least one channel in a given radio access network. Moreover, as used herein, a "shared" carrier may be an unlicensed carrier that is shared by different radio access networks and/or technologies, or a carrier that is shared in some other way and/or for some other reason (e.g., a carrier shared only among the multiple devices of a single radio access network).

These techniques are discussed below primarily with reference to <NUM> NR technologies, and more specifically with reference to operation of the <NUM> NR network over an unlicensed carrier (i.e., NR-U operation). However, the techniques of this disclosure can apply to other radio access technologies, and/or to other types of shared carriers (e.g., licensed bands that are shared by devices of a single radio access network). In the case of licensed bands, a channel access procedure of the type described below may or may not be performed.

Referring first to <FIG>, a wireless communication network <NUM> includes a UE <NUM>, which can be any suitable device capable of wireless communications, as further discussed below. The wireless communication network <NUM> also includes a base station <NUM> associated with an NR-U cell <NUM> and connected (directly or indirectly) to a <NUM> core network (5GC) <NUM>. The base station <NUM> may operate as a <NUM> Node B (gNB), a distributed unit gNB (gNB-DU), or an integrated access backhaul (IAB) node, for example. While <FIG> depicts the base station <NUM> as serving only the cell <NUM>, it is understood that the base station <NUM> may also cover one or more additional cells not shown in <FIG>. In general, the wireless communication network <NUM> can include any number of base stations, and each of the base stations may cover one, two, three, or any other suitable number of cells.

<NUM> NR UEs operating in the cell <NUM>, including the UE <NUM>, can utilize an unlicensed carrier as well as portions of the radio spectrum allocated specifically to the service provider that operates the base station <NUM> and the 5GC <NUM>. When exchanging data using the <NUM> NR air interface, the UE <NUM> and base station <NUM> may share the unlicensed carrier with other devices of other radio access networks. For example, other UEs (not shown in <FIG>) may be subscribers of the service provider that operates the base station <NUM> and the 5GC <NUM>, and be capable of communicating with the base station <NUM> via the unlicensed carrier. In addition, or alternatively, other UEs utilizing the unlicensed carrier may communicate with a base station or network node other than the base station <NUM>, using a different radio access technology. <FIG> depicts an example of one such scenario, in which the UE <NUM> and base station <NUM> coexist with an access point (AP) <NUM>. The AP <NUM> can utilize spectrum that includes, or is included within, at least a portion of the unlicensed carrier when operating in a wireless local area network (WLAN) according to one of the IEEE <NUM> standards. The AP <NUM> may be configured to communicate with one or more other devices not shown in <FIG>, such as other UEs, for example. In other implementations and/or scenarios, the UE <NUM> and base station <NUM> also, or instead, coexist with devices operating according to other radio access technologies. In still another implementation and/or scenario, the base station <NUM> does not connect to the 5GC110, and can operate as an AP (e.g., similar to AP <NUM>). Thus, for example, the wireless communication network <NUM> may omit the 5GC <NUM>, or only use the 5GC <NUM> in certain scenarios.

The UE <NUM> is equipped with processing hardware <NUM>, which may include one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, the processing hardware <NUM> may include special-purpose processing units, such as a wireless communication chipset, for example. The processing hardware <NUM> includes a control channel monitoring module <NUM>, and the memory of the processing hardware <NUM> stores a monitoring configuration <NUM>. The control channel monitoring module <NUM> may be implemented using any suitable combination of hardware, software, and/or firmware. In one example implementation, the control channel monitoring module <NUM> includes a set of instructions that defines respective components of the operating system of the UE <NUM>, and one or more CPUs of the processing hardware <NUM> execute these instructions to perform the channel monitoring functionality. In another implementation, the control channel monitoring module <NUM> is implemented using firmware as a part of a wireless communication chipset.

In operation, the control channel monitoring module <NUM> monitors a control channel in accordance with the monitoring configuration <NUM>, which the gNB <NUM> provides to the UE <NUM>. In some implementations and/or scenarios, the control channel monitoring module <NUM> monitors a PDCCH. In other implementations and/or scenarios, however, the control channel monitoring module <NUM> monitors a group-common PDCCH (GC-PDCCH). The monitoring configuration <NUM> can include descriptions of patterns of control channel occasions as well as the corresponding search space configuration. Each "control channel occasion" may represent a time or time window in which the gNB <NUM> can (i.e., according to a specification of the wireless communication network), but does not necessarily, transmit control channel information to the UE <NUM>. As used herein, a "pattern" of control channel occasions refers to a temporal distribution of control channel occasions that repeats once per time unit, where the time unit is fixed and may be of any suitable length or duration depending on the implementation (e.g., a time slot, a set of N contiguous time slots, a subframe, etc.). As a simple example, a pattern might include only a single control channel occasion at the beginning of each time slot. Depending on the implementation, the pre-transmission pattern may contain more control channel occasions per time unit than the transmission pattern (e.g., to provide a finer time granularity in which the gNB <NUM> can send control channel information to a user device), less control channel occasions per time unit than the transmission pattern, or the same number of control channel occasions per time unit (albeit with a different distribution and/or time-shift).

The base station <NUM> is equipped with processing hardware <NUM>, which may include one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, the processing hardware <NUM> may include special-purpose processing units, such as a wireless communication chipset, for example. The processing hardware <NUM> in the example implementation of <FIG> includes a channel access module <NUM>, a resource allocation unit <NUM>, and a COT signal controller <NUM>.

The channel access module <NUM> performs a channel access procedure, such as an LBT procedure, to gain access to the shared carrier in the NR-U cell <NUM>. When the channel access procedure is successful, the channel access module <NUM> determines that the gNB <NUM> has obtained or established a COT and accordingly can transmit various signals during the COT. The resource allocation unit <NUM> allocates to the UE <NUM> radio resources (i.e., time-frequency resources) and configuration parameters such as monitoring patterns of control channel (e.g., PDCCH) occasions, control resource sets (CORESETs), search spaces, etc. As discussed further below, the UE <NUM> can combine these control channel monitoring patterns in various ways to generate a pre-transmission monitoring pattern and a transmission monitoring pattern (or more specifically, in this implementation, a pre-COT monitoring pattern and a COT monitoring pattern). The COT signal controller <NUM> determines when the gNB <NUM> transmits, to the UE <NUM>, an indication that the gNB <NUM> has gained a COT. The COT signal controller <NUM>, in some implementations, also determines which format the gNB <NUM> should utilize for the indication. Example functionality of the components <NUM>, <NUM>, and <NUM> is discussed in more detail below, with reference to various example scenarios and monitoring patterns.

For simplicity, <FIG> does not depict various components of the UE <NUM> and the base station <NUM>. In addition to the components mentioned above, for example, the UE <NUM> and the base station <NUM> include respective transceivers, which comprise various hardware, firmware, and/or software components configured to transmit and receive wireless signals. The processing hardware <NUM> and the processing hardware <NUM> can send commands and exchange information with the respective transceivers as needed to perform various connection establishment procedures, perform various RRC or mobility management (MM), or communicate with other network elements, etc..

<FIG> illustrate several example configurations according to which the UE <NUM> can monitor a PDCCH. Generally speaking, the UE <NUM> monitors the PDCCH during at least two time intervals: before the gNB <NUM> gains access to the shared carrier and after the UE <NUM> receives an indication that the gNB <NUM> has gained access to the shared carrier. The UE <NUM> monitors the PDCCH associated with the shared carrier according to different patterns of PDCCH occasions during these two intervals, but with a certain overlap in the occasions of those patterns. Generally, a lower frequency of occasions causes the UE <NUM> to consume less power by, in at least some implementations, reduces the number of opportunities for the gNB <NUM> to send control channel information to the UE <NUM>.

Referring first to <FIG> and <FIG>, the gNB <NUM> in an example scenario <NUM> determines <NUM> to configure the UE <NUM> to monitor the PDCCH according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions. The gNB <NUM> indicates <NUM> the first and second patterns <NUM>, <NUM> to the UE <NUM>, e.g., by transmitting one or more configuration messages to the UE <NUM> via the shared carrier, as discussed further below. Generally, the UE <NUM> generates a dynamic monitoring schedule <NUM> using the patterns <NUM> and <NUM>, as is also discussed in further detail below. In the example pattern <NUM>, PDCCH occasions <NUM> occur at the beginning of each respective time unit <NUM>, where each time unit <NUM> can be a time slot, a set of N contiguous time slots, a subframe, etc. In the example pattern <NUM>, PDCCH occasions <NUM> occur at or near the mid-point of each respective time unit <NUM>. In general, the PDCCH occasions <NUM> and <NUM> can occur at any time or times within the time unit <NUM>. While the occasions <NUM> and <NUM> are referred to herein as PDCCH occasions, the techniques of this disclosure may also apply to GC-PDCCH occasions or other types of control channel occasions.

With continued reference to <FIG> and <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> begins at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM> that includes all PDCCH occasions of the patterns <NUM> and <NUM>. In other words, the UE <NUM> during this time monitors the PDCCH in accordance with the logical union of the patterns <NUM> and <NUM>. During each time unit <NUM> of the pre-COT <NUM>, the UE <NUM> monitors the PDCCH during both occasions <NUM> and occasions <NUM>. After the gNB <NUM> gains access to the shared carrier to establish <NUM> the COT <NUM> (e.g., using channel access module <NUM>), the gNB <NUM> indicates <NUM> to the UE <NUM> that the COT <NUM> has started. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH in accordance with the pattern <NUM>, and no longer monitors the PDCCH in accordance with the pattern <NUM>.

To indicate <NUM> to the UE <NUM> that the COT <NUM> has started, the gNB <NUM> may transmit a WUS, a signal generally indicating that the COT <NUM> has started (e.g., a "COT indicator"), a signal indicating the structure of the COT <NUM> (e.g., the duration of COT <NUM>), or another suitable signal (e.g., any suitable signal generated by COT signal controller <NUM>) indicating that the UE <NUM> is to stop monitoring according to the pattern <NUM>. Depending on the implementation, the gNB <NUM> may transmit the WUS or other signal at time <NUM>, during the first PDCCH occasion of pattern <NUM> or <NUM> that occurs after time <NUM> (in this example, occasion 314a), or at another suitable time. In some implementations and/or scenarios, the gNB <NUM> transmits a signal indicating that the COT <NUM> has started only one time. In other implementations and/or scenarios, the gNB <NUM> transmits such a signal multiple times, so as to increase the probability that the UE <NUM> receives the signal and thus knows when to stop monitoring according to the pattern <NUM>. In some implementations, the gNB <NUM> indicates <NUM> the COT <NUM> duration in a broadcast message. Several example techniques for indicating <NUM> that the COT <NUM> has started are discussed in more detail below.

In the example scenario reflected in <FIG>, the COT <NUM> starts during a time unit 310a, after the occasion <NUM> of the pattern <NUM> within time unit 310a has occurred, but before the occasion <NUM> of the pattern <NUM> within time unit 310a (i.e., occasion 314a in <FIG>) occurs. The UE <NUM> in this implementation thus monitors the PDCCH during the specific occasion 314a, but does not monitor the occasions <NUM> starting with the next time unit 310b for the duration of the COT <NUM>. For clarity, <FIG> illustrates, with dashed outline, the first occasion 314b of pattern <NUM> during which the UE <NUM> does not monitor the PDCCH. In a different scenario (not depicted in <FIG>), where the UE <NUM> fails to receive the WUS or other signal from the gNB <NUM> indicating that the COT <NUM> has started, the UE <NUM> would monitor the PDCCH during the occasion 314b, and in each subsequent occasion <NUM> of the pattern <NUM>.

In another implementation, after the UE <NUM> receives the indication that the COT <NUM> has started, the UE <NUM> continues to monitor the PDCCH according to both pattern <NUM> and pattern <NUM> for a certain amount of time, or for a certain number of PDCCH occasions, etc., which the gNB <NUM> can configure dynamically or which can be a part of the corresponding 3GPP specification. Thereafter, but still during the COT <NUM>, the UE <NUM> transitions to monitoring the PDCCH only during the occasions <NUM> of the pattern <NUM>. In yet another implementation, the UE <NUM> switches from the logical union of the patterns <NUM>, <NUM> to the pattern <NUM> only (rather than the pattern <NUM> only) after receiving the indication from the gNB <NUM>.

Thus, the UE <NUM> monitors the PDCCH according to the pattern <NUM> regardless of whether the UE <NUM> has received an indication that the COT <NUM> has started, but utilizes the pattern <NUM> only during the pre-COT <NUM> (or possibly also, as noted above, for some relatively short time at the beginning of the COT <NUM>). The occasions <NUM> accordingly define the overlap between the pre-COT pattern <NUM> that the UE <NUM> uses during the pre-COT <NUM> and the COT pattern <NUM> that the UE <NUM> uses the during the COT <NUM>. The pre-COT pattern <NUM> and the COT pattern <NUM> in this example overlap in only a single PDCCH occasion per time unit <NUM>, at the beginning of each time unit <NUM>. More generally, however, the pre-COT pattern <NUM> and the COT pattern <NUM> may overlap in any suitable number of PDCCH occasions per time unit <NUM>, and at any position or positions within the time unit <NUM>.

The overlapping occasions between the pre-COT pattern <NUM> and the COT pattern <NUM> allow the gNB <NUM> to know at least some times during which the UE <NUM> should be monitoring the PDCCH, regardless of whether the UE <NUM> has yet received the signal from the gNB <NUM>, and regardless of whether the UE <NUM> has yet switched from the pre-COT pattern <NUM> to the COT pattern <NUM>. This is particularly important because the UE <NUM> might miss the signal indicating that the gNB <NUM> has established the COT <NUM>, and because the UE <NUM> does not (in at least some implementations) acknowledge receipt of such a signal. Thus, the gNB <NUM> may generally be unaware of whether the UE <NUM> knows that the COT <NUM> has started. In some implementations, the gNB <NUM> can transmit, via the PDCCH, one or more additional indications that the COT <NUM> has started, during one of the occasions <NUM> (again, because the gNB <NUM> is aware that the UE <NUM> monitors the PDCCH according to the pattern <NUM>, in both the pre-COT pattern <NUM> and the COT pattern <NUM>). Alternatively or additionally, the gNB <NUM> may leverage the fact that the UE <NUM> is monitoring the PDCCH at least according to the pattern <NUM> to send control information to the UE <NUM> in one or more of the occasions <NUM>.

Further, because the COT pattern <NUM> includes fewer occasions per time unit <NUM> than the pre-COT pattern <NUM>, transitioning from the pre-COT pattern <NUM> to the COT pattern <NUM> allows the UE <NUM> to save power, as compared to the UE <NUM> monitoring the PDCCH at the higher frequency during both the pre-COT <NUM> and the COT <NUM>. Still further, because the pre-COT pattern <NUM> includes more occasions per time unit <NUM> than the COT pattern <NUM>, the gNB <NUM> during the pre-COT <NUM> has more opportunities to transmit information to the UE <NUM> on the PDCCH. After the COT <NUM> terminates, the UE <NUM> may revert to monitoring according to the pre-COT pattern (not shown), another pattern, or no pattern at all, depending on the embodiment.

Additionally or alternatively, the gNB <NUM> can transmit, on the PDCCH during one of the occasions <NUM>, a DCI which can include downlink assignment information indicating that the UE <NUM> can receive on a certain physical downlink shared channel (PDSCH), or an uplink grant indicating that the UE <NUM> can transmit on a certain physical uplink shared channel (PUSCH). Thus, more opportunities for the gNB <NUM> to transmit on the PDCCH may result in more opportunities for the UE <NUM> to transmit or receive higher-layer messages or data.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> should start monitoring according to the pattern <NUM>, or indicating that the COT <NUM> has ended. In addition to monitoring the PDCCH according to the pattern <NUM>, the UE <NUM> may monitor the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may start monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may start to monitor the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described below for <FIG>), the UE <NUM> starts monitoring the patterns <NUM> and <NUM> after the end of the COT <NUM>.

Now referring to <FIG>, the gNB <NUM> in an example scenario <NUM> provides to the UE <NUM> multiple indications of a COT (e.g., COT <NUM>), during which the shared carrier is available to the gNB <NUM>. As discussed above, the UE <NUM> in some cases may miss the indication that the gNB <NUM> has established a COT, and the UE <NUM> may not confirm to the gNB <NUM> when the UE <NUM> has successfully received such an indication. The gNB <NUM> in the implementation of <FIG> transmits the indication multiple times to increase the probability that the UE <NUM> is aware of the COT. However, this alone may not provide the UE <NUM> with sufficient information to know when the COT will end (e.g., time <NUM>), and thus the UE <NUM> may not know how long to monitor the PDCCH according to the COT pattern (e.g., pattern <NUM>).

Accordingly, to ensure that the UE <NUM> correctly identifies the end of the COT, the gNB <NUM> may include in each of the multiple transmissions an indication of the remaining duration of the COT. In particular, immediately or shortly after the gNB <NUM> establishes 408a a COT, the gNB <NUM> indicates 410a a first duration of the COT to the UE <NUM>, e.g., by transmitting a first COT structure indication to the UE <NUM> via the shared carrier. The first duration may be an entire duration of the COT, which the gNB <NUM> may determine when the gNB <NUM> is granted access to the shared channel. At a later time, gNB <NUM> determines 408b the remaining (shorter) duration of the COT and indicates 410b the remaining duration to the UE <NUM>, e.g., by transmitting a second COT structure indication to the UE <NUM> via the shared carrier. The gNB <NUM> may determine the remaining duration by subtracting a current timer value (e.g., a value of a timer that the gNB <NUM> started when the COT began) from the original/full duration of the COT. The gNB <NUM> may indicate the remaining duration of the COT using any suitable format and parameters, e.g., the end time (e.g., time <NUM>) relative to the current time unit, the number of remaining time units, the number of remaining microseconds, etc..

Although the gNB <NUM> in the example scenario <NUM> indicates the COT duration two times, in general the gNB <NUM> can provide any suitable number of indications of the remaining COT time to the UE <NUM>.

<FIG> illustrates another example scenario <NUM> in which the gNB <NUM> configures the UE <NUM> with two partially overlapping patterns, and the UE <NUM> uses these partially overlapping patterns to monitor a PDCCH according to a pre-COT pattern and a COT pattern. However, unlike the scenario of <FIG>, the UE <NUM> in this case transitions from monitoring the PDCCH according to one of the patterns to monitoring the PDCCH according to the logical intersection of the two patterns. Again, the overlap in the occasions of the pre-COT and COT patterns allows the gNB <NUM> to rely on at least one occasion per time unit in which the UE <NUM> should be monitoring the PDCCH, regardless of whether UE <NUM> has yet received the signal from the gNB <NUM>, and regardless of whether the UE <NUM> has yet switched from the pre-COT pattern to the COT pattern.

Referring to both <FIG> and <FIG>, the gNB <NUM> first determines <NUM> to configure the UE <NUM> to monitor the PDCCH according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions. As seen in <FIG>, the patterns <NUM> and <NUM> partially overlap, with an occasion 612a of the pattern <NUM> coinciding with an occasion 614a of the pattern <NUM>. Thus, an overlapping occasion occurs once every two consecutive time units <NUM>. In other implementations and/or scenarios, the gNB <NUM> may select or set monitoring patterns <NUM> and <NUM> such that the overlapping occasions are more or less frequent than shown in <FIG>.

The gNB <NUM> indicates <NUM> the patterns <NUM> and <NUM> to the UE <NUM>, e.g., by transmitting one or more configuration messages to the UE <NUM> via the shared carrier, as discussed further below. The UE <NUM> uses the patterns <NUM> and <NUM> to generate a dynamic monitoring schedule <NUM>. Similar to the schedule <NUM> of <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> starts at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM>. Also similar to the scenario of <FIG>, the pre-COT pattern <NUM> is equivalent to the first pattern <NUM>. In an alternative implementation, the pre-COT pattern <NUM> is a logical union of the patterns <NUM> and <NUM>, while the COT pattern <NUM> is the logical intersection of the patterns <NUM> and <NUM>.

Next, the gNB <NUM> establishes <NUM> the COT <NUM>, and indicates <NUM> to the UE <NUM> that the COT <NUM> has started, or to monitor the logical intersection of the patterns <NUM> and <NUM>. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH in accordance with a COT pattern <NUM>, which is the logical intersection of the patterns <NUM> and <NUM>. In other words, the UE <NUM> monitors the PDCCH only during those PDCCH occasions of the pattern <NUM> that overlap a PDCCH occasion of the pattern <NUM>, and vice versa. For example, the PDCCH occasion 612b of the pattern <NUM> coincides with the PDCCH occasion 614b of the pattern <NUM>, and thus the UE <NUM> monitors the PDCCH during this overlapping occasion. On the other hand, the UE <NUM> does not monitor the PDCCH during the occasion 612c of pattern <NUM>, because occasion 612c does not coincide with any occasion of pattern <NUM>, and does not monitor the PDCCH during the occasion 614c of pattern <NUM>, because occasion 614c does not coincide with any occasion of pattern <NUM>.

The overlapping occasions between the pre-COT pattern <NUM> and the COT pattern <NUM> allow the gNB <NUM> to know at least some times during which the UE <NUM> should be monitoring the PDCCH, regardless of whether the UE <NUM> has yet received a WUS or other signal from the gNB <NUM>, and regardless of whether the UE <NUM> has yet switched from the pre-COT pattern <NUM> to the COT pattern <NUM>. This gNB <NUM> can make use of this knowledge when re-transmitting signals indicating the COT <NUM> to the UE <NUM>, and/or when sending control information to the UE <NUM>, as discussed above in connection with <FIG> and <FIG>.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> is to start monitoring the PDCCH according to the pattern <NUM> instead of the logical intersection of the patterns <NUM> and <NUM>, or indicating that the COT <NUM> has ended. Thereafter, the UE <NUM> monitors the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may start monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may start to monitor the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described for <FIG> above), the UE starts monitoring the pattern <NUM> after the end of the COT <NUM>.

<FIG> illustrates another example scenario <NUM> in which the gNB <NUM> configures the UE <NUM> with two patterns, with one pattern being a subset of the other pattern, and the UE <NUM> uses these patterns to monitor a PDCCH according to a pre-COT pattern and a COT pattern. Thus, <FIG> and <FIG> are a special case of <FIG> and <FIG>, respectively, because the COT pattern is a subset of the pre-COT pattern.

Referring to both <FIG> and <FIG>, the gNB <NUM> first determines <NUM> to configure the UE <NUM> to monitor the PDCCH according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions. In this example, the pattern <NUM> is a subset of the pattern <NUM>. As illustrated in <FIG>, occasion <NUM> of pattern <NUM> coincides with the first occasion <NUM> of pattern <NUM> in each time unit <NUM>. However, the pattern <NUM> also includes a second occasion in each time unit <NUM> that is not present in the pattern <NUM>.

The gNB <NUM> indicates <NUM> the patterns <NUM> and <NUM> to the UE <NUM>, e.g., by transmitting one or more configuration messages to the UE <NUM> via the shared carrier, as discussed further below. The UE <NUM> uses the patterns <NUM> and <NUM> to generate a dynamic monitoring schedule <NUM>. Similar to the schedule <NUM> of <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> starts at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM>. In this scenario, the pre-COT pattern <NUM> is the pattern <NUM>, which happens to include every occasion of the pattern <NUM> and thus is equivalent to the logical union of the patterns <NUM> and <NUM>.

Next, the gNB <NUM> establishes <NUM> the COT <NUM> and indicates <NUM> to the UE <NUM> that the COT <NUM> has been established or to monitor the PDCCH according to the pattern <NUM>. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a COT pattern <NUM>, which is simply the pattern <NUM>. Because the COT pattern <NUM> is a subset of the pattern <NUM>, the COT pattern <NUM> is equivalent to the logical intersection of the patterns <NUM> and <NUM>.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> is to start monitoring the PDCCH according to the pattern <NUM> instead of the pattern <NUM>, or indicating that the COT <NUM> has ended. The UE <NUM> monitors the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may start monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may start to monitor the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described for <FIG> above), the UE <NUM> starts monitoring the pattern <NUM> after the end of the COT <NUM>.

In the examples above, the UE <NUM> reduces the frequency of monitoring the PDCCH by switching from a pre-COT pattern to a COT pattern. In other implementations, however, the UE <NUM> can begin to monitor the PDCCH more frequently, rather than less frequently, during the COT. This alternative approach retains the advantage that, if the UE <NUM> has missed the indication that the COT has started and thus did not switch from the pre-COT pattern to the COT pattern, the gNB <NUM> nevertheless knows that the UE <NUM> is monitoring the PDCCH at least during the overlapping occasions (i.e., the occasions of the COT pattern that overlap an occasion of the pre-COT pattern). Moreover, in those cases where the UE <NUM> does not receive the indication that a COT has started and therefore continues to monitor the PDCCH according to the pre-COT pattern, the reduced frequency of occasions in the pre-COT pattern allows the UE <NUM> to save power.

Referring for example to <FIG> and <FIG>, the gNB <NUM> first determines <NUM> to configure the UE <NUM> to monitor a PDCCH according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions. The gNB <NUM> indicates <NUM> the patterns <NUM> and <NUM> to the UE <NUM>, e.g., by transmitting one or more configuration messages to the UE <NUM> via the shared carrier, as discussed further below. The UE <NUM> uses these patterns <NUM> and <NUM> to generate a dynamic monitoring schedule <NUM>. Similar to the schedule <NUM> of <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> starts at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM>, which in this example is equivalent to the first pattern <NUM>.

Next, the gNB <NUM> establishes <NUM> the COT <NUM>, and indicates <NUM> to the UE <NUM> that the COT <NUM> has started. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH by continuing to monitor the PDCCH according to the first pattern <NUM> and also beginning to monitor the PDCCH according to the second pattern <NUM>. Thus, the COT pattern <NUM> in this example is a logical union of the patterns <NUM> and <NUM>.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> is to stop monitoring the PDCCH according to the pattern <NUM>, or indicating that the COT <NUM> has ended. The UE <NUM> monitors the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may stop monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may stop monitoring the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described for <FIG> above), the UE <NUM> stop monitoring the pattern <NUM> after the end of the COT <NUM>.

Referring next to <FIG> and <FIG>, the gNB <NUM> first determines <NUM> to configure the UE <NUM> to monitor a PDCCH according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions. As seen in <FIG>, the patterns <NUM> and <NUM> partially overlap, with an occasion 1212a of the pattern <NUM> coinciding with an occasion 1214a of the pattern <NUM>. Thus, in this example, an overlapping occasion occurs once every two consecutive time units <NUM>. In other implementations and/or scenarios, the gNB <NUM> may select or set monitoring patterns <NUM> and <NUM> such that the overlapping occasions are more or less frequent than shown in <FIG>.

The gNB <NUM> indicates <NUM> the patterns <NUM> and <NUM> to the UE <NUM>, e.g., by transmitting one or more configuration messages to the UE <NUM> via the shared carrier, as discussed further below. The UE <NUM> uses these patterns <NUM> and <NUM> to generate a dynamic monitoring schedule <NUM>. Similar to the schedule <NUM> of <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> starts at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM>, which in this example is equivalent to the first pattern <NUM>.

Next, the gNB <NUM> establishes <NUM> the COT <NUM>, and indicates <NUM> to the UE <NUM> that the COT <NUM> has started. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH by continuing to monitor the PDCCH according to the first pattern <NUM> and also beginning to monitor the PDCCH according to the second pattern <NUM>. Thus, the COT pattern <NUM> in this example is a logical union of the patterns <NUM> and <NUM>. In another example, the COT pattern <NUM> is simply the second pattern <NUM>.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> is to stop monitoring the PDCCH according to the pattern <NUM>, or indicating that the COT <NUM> has ended. The UE <NUM> monitors the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may stop monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may stop monitoring the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described for <FIG> above), the UE <NUM> stops monitoring the pattern <NUM> after the end of the COT <NUM>.

Referring next to <FIG> and <FIG>, the gNB <NUM> first determines <NUM> to configure the UE <NUM> according to a first pattern <NUM> of PDCCH occasions and a second pattern <NUM> of PDCCH occasions, with the pattern <NUM> being a subset of the pattern <NUM>. As illustrated in <FIG>, occasion <NUM> of pattern <NUM> coincides with the first occasion <NUM> of pattern <NUM> in each time unit <NUM>. However, the pattern <NUM> includes a second occasion in each time unit <NUM> that is not present in the pattern <NUM>.

The gNB <NUM> indicates <NUM> the patterns <NUM> and <NUM> to the UE <NUM>. The UE <NUM> uses the patterns <NUM> and <NUM> to generate a dynamic monitoring schedule <NUM>. Similar to the schedule <NUM> of <FIG>, the schedule <NUM> covers a pre-COT <NUM>, which is an interval of time before the gNB <NUM> establishes a COT <NUM>, and the COT <NUM> itself. As seen in <FIG>, the COT <NUM> starts at a time <NUM> and ends at a time <NUM>. During the pre-COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH according to a pre-COT pattern <NUM>, which in this example is the first pattern <NUM>.

Next, the gNB <NUM> establishes <NUM> the COT <NUM>, and indicates <NUM> to the UE <NUM> that the COT <NUM> has started. In response to this indication <NUM>, and during the COT <NUM>, the UE <NUM> monitors <NUM> the PDCCH by continuing to monitor according to the first pattern <NUM>, and beginning to also monitor according to the second pattern <NUM> (i.e., by monitoring according to the logical union of the patterns <NUM> and <NUM>). Because the pattern <NUM> is a subset of the pattern <NUM>, the COT pattern <NUM> is also equivalent to the pattern <NUM>.

In some situations, the gNB <NUM> may transmit to the UE <NUM> a signal indicating that the UE <NUM> is to stop monitoring the PDCCH according to the pattern <NUM>, or indicating that the COT <NUM> has ended. The UE <NUM> monitors the PDCCH according to the pattern <NUM> in response to the signal. The UE <NUM> may stop monitoring the PDCCH according to the pattern <NUM> immediately upon receiving the signal, or may stop monitoring the PDCCH according to the pattern <NUM> after a certain amount of time passes after receiving the signal. The signal may be a DCI, for example. In other situations, if the UE <NUM> does not receive the signal and knows the end of the COT <NUM> (e.g., according to a COT structure indication as described for <FIG> above), the UE <NUM> stops monitoring the PDCCH according to the pattern <NUM> after the end of the COT <NUM>.

Various, more specific implementations are now discussed with reference to the example scenarios of <FIG> discussed above.

In some implementations and/or scenarios, the control channel the UE <NUM> monitors may be a GC-PDCCH rather than a PDCCH. When the control channel is a GC-PDCCH, the gNB <NUM> can configure the UE <NUM> with a certain group-common radio network temporary identifier (GC-RNTI), which the UE <NUM> can use to monitor the GC-PDCCH. For example, the UE <NUM> can monitor the GC-PDCCH during PDCCH occasions according to the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. Alternatively, the UE <NUM> can monitor the GC-PDCCH according to the pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, or according to the pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. As another example, the gNB <NUM> can configure the UE <NUM> specifically with GC-PDCCH occasions using a SearchSpace information element (IE), or another suitable indication of a search space configuration.

In the example scenarios of <FIG>, the gNB <NUM> indicates <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> first and second patterns to the UE <NUM> using one or more configuration messages. In one implementation, the gNB <NUM> transmits an RRC message that indicates the patterns, such as RRC Reconfiguration, RRC Setup, or RRC Resume, for example. A configuration message also can include at least one DCI, and/or a MAC control element (CE). For each of the patterns <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, and <NUM>/<NUM>, the DCI, MAC CE, or other confirmation message may indicate the separation in time between consecutive PDCCH occasions for each pattern, the duration of each PDCCH occasion in the patterns, and so on. In response to the one or more configuration messages, the UE <NUM> may transmit one or more messages, such as a MAC confirmation CE, for example. In another implementation and/or scenario, the UE <NUM> transmits to the gNB <NUM> a physical uplink control channel (PUCCH) indication in response to the one or more configuration messages from the gNB <NUM>.

Further, the one or more configuration messages may include a CORESET to indicate a time-frequency resource allocated to the UE <NUM>. For example, the configuration message(s) may indicate a certain frequency resource (e.g., one or more frequency ranges) for a certain time duration (e.g., one, two, or three OFDM symbols) during which the UE <NUM> is to search for a DCI. The gNB <NUM> may use a ControlResourceSet IE, for example, to transmit this configuration to the UE <NUM>. The gNB <NUM> in one example configuration provides a CORESET that applies to both patterns in each pair <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, or <NUM>/<NUM>. Thus, when the UE <NUM> monitors a control channel according to one pattern or the other pattern, the UE <NUM> during a PDCCH occasion searches for a DCI in accordance with the CORESET information. In another implementation, however, the gNB <NUM> provides a separate CORESET for each of the two patterns in the pair <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, or <NUM>/<NUM>. In this implementation, the UE <NUM> searches for a DCI in accordance with a first CORESET during PDCCH occasions associated with the first pattern and a different, second CORESET during PDCCH occasions associated with the second pattern.

As one particular example, the gNB <NUM> may transmit to the UE <NUM> an RRC message that includes two search space configurations (e.g., two SearchSpace IEs) and two CORESET configurations (e.g., two ControlResourceSet IEs). Alternatively, the gNB <NUM> may transmit to the UE <NUM> a first RRC message that includes a first search space configuration and a corresponding CORESET, and a second RRC message that includes a different, second search space configuration and a corresponding CORESET. As in the implementations described above, the gNB <NUM> may use SearchSpace and ControlResourceSet IEs to provide the search space configurations and CORESETs. The two CORESETs the gNB <NUM> provides in this implementation may be the same or different. As yet another example, the gNB <NUM> may transmit to the UE <NUM> three RRC messages as part of the configuration: a first RRC message that includes a first search space configuration, a second RRC message that includes a second search space configuration, and a third RRC message that includes a CORESET for use with the two patterns (or, two CORESETs for use with the respective patterns).

As discussed above, the gNB <NUM> in some cases transmits a WUS or COT indicator. The WUS or the COT indicator may include a preamble, a Zadoff-Chu (ZC) sequence, a synchronization signal (SS), a primary SS, a secondary SS, a reference signal (RS) such as a channel state information SS (CSI-RS), a demodulation reference signal (DMRS) in a PDCCH or a DMRS in a GC-PDCCH, and/or a DCI in a PDCCH. In general, the WUS or COT indicator may depend on the implementation of the gNB <NUM>, or the gNB <NUM> may be able to select a different WUS or COT indicator depending on the capability of the UE <NUM> and/or the configuration of the NR-U cell <NUM>.

In addition to using a WUS or COT indicator to notify the UE <NUM> that the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> has started, the gNB <NUM> may transmit a WUS to the UE <NUM> to cause the UE <NUM> to start monitoring the PDCCH occasions according to the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. For example, the UE <NUM> may not monitor any PDCCH occasions until first receiving a WUS from the gNB <NUM>. In other implementations, the UE <NUM> may monitor PDCCH occasions according to the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> regardless of whether the UE <NUM> has received a WUS from the gNB <NUM>.

As was also discussed above, the gNB <NUM> in some implementations provides to the UE <NUM> a COT structure indication that indicates the ending time and/or the duration of the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. For example, the COT structure indication may indicate the COT ending time or duration as X (e.g., <NUM>, <NUM>, <NUM>,. N, where N is a positive integer) time units (e.g., OFDM symbols, slots, subrames, frames) relative to a certain starting time that the UE <NUM> knows a priori or can otherwise determine. As a more specific example, the starting time may be the time unit during which the UE <NUM> receives the COT structure indication. Thus, if the UE <NUM> receives the COT during the Y-th time unit, and the COT structure indicates a COT duration of X, the UE <NUM> can determine that the COT lasts from the Y-th time unit until the (X + Y)-th time unit. As another example, the starting time can occur n time units after the UE <NUM> receives the COT structure indication, and both the UE <NUM> and the gNB <NUM> can store the same value of n. The UE <NUM> in this case can determine that the COT lasts from the (Y+n)-th time unit until the (X + Y + n)-th time unit.

Moreover, the gNB <NUM> in some cases can transmit multiple instances of the COT structure indication, and vary the content of the indication according to the remaining duration of the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> (e.g., as discussed above in connection with <FIG>). For example, the gNB <NUM> in the first instance may transmit a COT structure indication according to which the COT is Y time units long. In the second instance that occurs L time units later, however, the gNB <NUM> may transmit a COT structure indication according to which the remaining duration of the COT is Y-L time units. Similar to the examples above, the values of Y and L can be <NUM>, <NUM>, <NUM>, or any other suitable positive integer. Also similar to the examples above, the COT structure indication may reference the duration of a COT and/or the ending time of the COT relative to a starting time of which the UE <NUM> is aware (e.g., based on the 3GPP specification or an explicit indication from the gNB <NUM>). The gNB <NUM> in some implementations transmits the multiple instances of the COT structure indication during the monitoring occasions of the pre-COT pattern, or more specifically during the monitoring occasions of the pre-COT and COT patterns that overlap each other.

In implementations where the gNB <NUM> indicates <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> the duration of the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> in a broadcast message, the broadcast message may be a system information block (SIB), or a dedicated message such as RRC Setup, RRC Resume, RRC Reestablishment, or RRC Reconfiguration, for example. In yet another implementation, each of the UE <NUM> and the gNB <NUM> stores a predefined duration of the COT in a respective local memory.

In some implementations where the UE <NUM> and the gNB <NUM> can use a GC-PDCCH, the gNB <NUM> in various scenarios may transmit a COT structure indication on a PDCCH or a GC-PDCCH, during either a PDCCH occasion or a GC-PDCCH occasion. As one example, the gNB <NUM> transmits a COT structure indication on a PDCCH during a PDCCH occasion of the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. As another example, the gNB <NUM> transmits a COT structure indication on a GC-PDCCH during a PDCCH occasion of the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. As yet another example, the gNB <NUM> transmits a COT structure indication on a GC-PDCCH during a GC-PDCCH occasion of the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> or another pattern of GC-PDCCH occasions.

The gNB <NUM> may transmit a DCI during a PDCCH occasion, and include the COT indication in the DCI. In other implementations, the gNB <NUM> transmits a COT structure indication in a MAC protocol data unit (PDU). The COT structure indication may be a MAC CE in a MAC PDU, for example. As one alternative, the COT structure indication may be an RRC IE in an RRC message, and the gNB <NUM> includes the RRC message in a MAC PDU.

When the gNB <NUM> in the examples above establishes the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, the gNB <NUM> successfully completes a channel access procedure, such as an LBT procedure, on the shared carrier. The gNB <NUM> as a result acquires a grant to the channel.

When the gNB <NUM> uses a WUS or a COT indicator to notify the UE <NUM> that the UE <NUM> should start monitoring the PDCCH according to the corresponding COT pattern, the gNB <NUM> may notify the UE <NUM> of the duration of the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> prior to transmitting the WUS or the COT indicator. To this end, the gNB <NUM> can use a COT structure indication. However, if the UE <NUM> and the gNB <NUM> are already are aware of a predefined duration of the COT, the gNB <NUM> need not transmit a COT structure indication or another indicator of the duration of the COT.

In some implementations, the gNB <NUM> transmits a WUS to the UE <NUM> to cause the UE <NUM> to begin monitoring the PDCCH according to the pre-COT pattern <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, during the pre-COT time <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. The gNB <NUM> may then transmits a COT structure indication during one of the PDCCH occasions of the pre-COT pattern. In another implementation, the gNB <NUM> transmits a COT structure indication during one of the PDCCH occasions of the pre-COT pattern without transmitting a WUS prior to transmitting the COT structure indication.

The pre-COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, in various implementations or scenarios, may begin immediately after the UE <NUM> receives the indication <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> of the first and second patterns, or at some point after the UE <NUM> receives this indication. Moreover, the gNB <NUM> may provide the indication of the first pattern and the second pattern in different configuration messages at different times.

As described above, the pre-COT ends, and the COT <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> begins, at the instant when the gNB <NUM> establishes the COT. More generally, however, the COT start times <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> need not correspond precisely to the beginning of the COT. For example, the COT start time, for purposes of the UE <NUM> changing its monitoring pattern, may be the time when the UE <NUM> receives the indication <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> that the gNB <NUM> has established the COT, or another suitable time.

In some implementations, the schedule <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> includes at least one control channel occasion that is not a part of the corresponding pattern pair <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, <NUM>/<NUM>, or <NUM>/<NUM>. In some embodiments where the gNB <NUM> transmits a WUS to the UE <NUM> to indicate the start of a COT, for example, the UE <NUM> monitors the control channel immediately (or almost immediately) upon receiving the WUS, even if that time does not correspond to a control channel occasion of either pattern in the pair. Thus, for example, the UE <NUM> may monitor the PDCCH or GC-PDCCH for a time duration starting at (or very near to) time <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. This "extra" monitoring occasion may have the same duration as the other occasions of the pattern pair, or may have a different duration.

Some example methods that can be implemented in devices operating in the wireless communication network <NUM>, or another suitable network, are now considered. These methods can be implemented in processing hardware, e.g., as software instructions executable on one or more processors.

<FIG> illustrates an example method <NUM> for monitoring a control channel (e.g., PDCCH or GC-PDCCH). The method <NUM> is implemented in a user device such as the UE <NUM>, for example (e.g., by the control channel monitoring module <NUM>).

At block <NUM>, the user device monitors the control channel on a shared carrier (e.g., monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, or monitoring <NUM> in <FIG>), according to a pre-transmission pattern of control channel occasions. The pre-transmission may be the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, or the pattern <NUM> of <FIG>, for example.

At block <NUM>, while monitoring the control channel according to the pre-transmission pattern of control channel occasions, the user device receives a signal indicating a transmission time (e.g., COT) during which the gNB <NUM> has access to the shared carrier (e.g., indication <NUM> in <FIG>, indication <NUM> in <FIG>, indication <NUM> in <FIG>, indication <NUM> in <FIG>, indication <NUM> in <FIG>, or indication <NUM> in <FIG>). The gNB <NUM> may have sought access to the shared carrier (e.g., using an LBT procedure) in order to transmit information such as DCI and/or other control data to the UE <NUM>.

At block <NUM>, the user device monitors the control channel on the shared carrier (e.g., monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, monitoring <NUM> in <FIG>, or monitoring <NUM> in <FIG>), according to a transmission pattern of control channel occasions (e.g., COT pattern <NUM> in <FIG>, COT pattern <NUM> in <FIG>, COT pattern <NUM> in <FIG>, COT pattern <NUM> in <FIG>, COT pattern <NUM> in <FIG>, or COT pattern <NUM> in <FIG>). At least one control channel occasion of the transmission pattern overlaps a control channel occasion of the pre-transmission pattern.

<FIG> illustrates an example method <NUM> for configuring a user device to monitor a control channel (e.g., PDCCH or GC-PDCCH). The method <NUM> is implemented in a base station such as the gNB <NUM>, for example (e.g., by the components <NUM>-<NUM>).

At block <NUM>, the base station determines that a shared carrier is available to the base station for a certain transmission time. Block <NUM> may include performing a successful LBT procedure to establish a COT, for example (e.g., establishing <NUM> in <FIG>, establishing <NUM> in <FIG>, establishing <NUM> in <FIG>, establishing <NUM> in <FIG>, establishing <NUM> in <FIG>, or establishing <NUM> in <FIG>).

At block <NUM>, the base station transmits a signal to the user device indicating a transmission time during which the shared carrier is available to the base station. The signal causes the user device to switch from monitoring a control channel on the shared carrier according to a pre-transmission pattern of control channel occasions before the transmission time (e.g., the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, or the monitoring <NUM> in <FIG>, according to the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, the pattern <NUM> of <FIG>, or the pattern <NUM> of <FIG>,respectively) to monitoring the control channel on the shared carrier according to a transmission pattern of control channel occasions during the transmission time (e.g., the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, the monitoring <NUM> in <FIG>, or the monitoring <NUM> in <FIG>, according to the COT pattern <NUM> of <FIG>, the COT pattern <NUM> of <FIG>, the COT pattern <NUM> of <FIG>, the COT pattern <NUM> of <FIG>, the COT pattern <NUM> of <FIG>, or the COT pattern <NUM> of <FIG>, respectively). The transmission pattern is different than the pre-transmission pattern, but includes at least one control channel occasion that overlaps a control channel occasion of the pre-transmission pattern.

The following additional considerations apply to the foregoing discussion.

A user device in which the techniques of this disclosure can be implemented (e.g., the UE <NUM>) can be any suitable device capable of wireless communications such as a smartphone, a tablet computer, a laptop computer, a mobile gaming console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a media-streaming dongle or another personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router. Further, the user device in some cases may be embedded in an electronic system such as the head unit of a vehicle or an advanced driver assistance system (ADAS). Still further, the user device can operate as an internet-of-things (IoT) device or a mobile-internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc..

Certain implementations are described in this disclosure as including logic or a number of components or modules. Modules may can be software modules (e.g., code stored on non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner. A hardware module can comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

When implemented in software, the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more special-purpose processors.

Claim 1:
A method, performed by a user device (<NUM>), of obtaining control channel information from a base station (<NUM>) that communicates with the user device (<NUM>) via a carrier in an unlicensed or otherwise shared spectrum, the method comprising:
receiving, from the base station (<NUM>) via the carrier, a first search space configuration indication indicating a pre-transmission pattern (<NUM>) of control channel occasions;
receiving, from the base station (<NUM>) via the carrier, a second search space configuration indication indicating a transmission pattern (<NUM>) of control channel occasions that is different than the pre-transmission pattern (<NUM>), but includes at least one control channel occasion that overlaps a control channel occasion of the pre-transmission pattern (<NUM>) and includes more or fewer control channel occasions per unit time than the pre-transmission pattern (<NUM>);
monitoring (<NUM>) a control channel on the carrier according to the pre-transmission pattern (<NUM>);
while monitoring the control channel according to the pre-transmission pattern (<NUM>), receiving (<NUM>), from the base station (<NUM>) via the carrier, a downlink control information, DCI, indicating that the user device (<NUM>) is to start monitoring according to the transmission pattern (<NUM>); and
in response to receiving the DCI, monitoring (<NUM>) the control channel on the carrier according to the transmission pattern (<NUM>) during a transmission time in which the carrier is available to the base station (<NUM>).