System and method for scheduling control channel information

Abstract

In order to obtain control channel information from a base station communicating with a user equipment via a shared carrier, the user equipment monitors a control channel on the shared carrier according to a pre-transmission pattern of control channel opportunities (1502). When monitoring the control channel using the pre-transmission pattern, the user equipment receives a signal from the base station via the shared carrier indicating a transmission time during which the shared carrier is available to the base station (1504). In response to receiving the signal, the user equipment monitors the control channel on the shared carrier according to the transmission pattern of the control channel opportunities during the transmission time, the transmission pattern of the control channel opportunities being different from the pre-transmission pattern but including at least one control channel opportunity that overlaps with the control channel opportunities of the pre-transmission pattern (1506).

Description

Technical Field

[0001] The present disclosure relates to wireless communications and, more particularly, to scheduling the transmission of control channel information in an unlicensed or otherwise shared spectrum. Background Art

[0002] This background description is for the purpose of generally presenting the context of the present disclosure. To the extent described in this background section, the work of the presently named inventors, and aspects that may otherwise not qualify as prior art as of filing, are not explicitly or implicitly admitted to be prior art against the present disclosure.

[0003] Some wireless communication networks allow compatible devices to share unlicensed carriers with other radio access technologies. In this case, in order to fairly allocate the shared medium, devices operating in the unlicensed carrier usually need to perform a channel access procedure before sending a message. In particular, the device may need to listen to other communications (i.e., detect energy) on the unlicensed carrier before sending information using the unlicensed carrier, thereby reducing or eliminating interference with communications of other networks / devices.

[0004] The Third Generation Partnership Project (3GPP) specifications for fifth generation (5G) New Radio (“NR”) networks, in particular 3GPP TS 38.899 v16.0.0 (addressing the use of unlicensed carriers by 5G NR devices under a study item commonly referred to as “NR-U”), seek to maintain consistency with other radio access technologies (such as 5G NR) by requiring 5G NR devices to perform a “listen before talk” (LBT) channel access procedure before transmitting over an unlicensed carrier. (IEEE 802.11)). This restriction on the use of unlicensed carriers 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 occupation time (COT) before sending physical downlink control channel (PDCCH) information to a user equipment (commonly referred to using the abbreviation "UE" for "user equipment") using an unlicensed carrier. Therefore, the user equipment does not know a priori when the base station may send control channel information, and does not know when to monitor the PDCCH. Continuously or nearly continuously monitoring the PDCCH is not a satisfactory solution because this would greatly increase power consumption at the user equipment.

[0005] According to one proposal, the user equipment will monitor the PDCCH at a relatively high rate until the user equipment receives a signal from the base station indicating that the base station has established the COT. Shortly thereafter, the user equipment begins to monitor the PDCCH at a relatively low rate. Although this method provides more opportunities for the base station to start sending control channel information via the PDCCH, and can also reduce power consumption in the user equipment, the problem still arises because the user equipment may fail to receive a signal indicating the start of the COT. Therefore, the base station may not know whether the user equipment has transitioned to a different PDCCH monitoring mode. Summary of the invention

[0006] The base station (e.g., gNB) of the present disclosure communicates with a user equipment via a shared carrier and uses a channel access procedure (e.g., LBT) to obtain access to the shared carrier. The base station configures the user equipment to monitor a control channel (e.g., PDCCH) according to one mode ("pre-transmission mode") of a control channel opportunity before a transmission time (e.g., COT) of the base station begins, and to monitor the control channel according to a different mode ("transmission mode") of a control channel opportunity when the transmission time is ongoing.

[0007] The pre-transmission mode and the transmission mode, although different, include at least one overlapping control channel opportunity. For example, the pre-transmission mode may include control channel opportunities at the beginning and midpoint of each time unit, while the transmission mode may include only a single control channel opportunity at the beginning of each time unit. By virtue of the overlapping (one or more) opportunities, the base station is aware of at least one opportunity per time unit in which the user equipment should monitor the control channel, regardless of whether the user equipment has received a signal from the base station indicating that the transmission time has begun, a signal indicating that the transmission time has ended, or a signal indicating a switch from the pre-transmission mode to the transmission mode, and regardless of whether the user equipment has switched from the pre-transmission mode to the transmission mode, or vice versa. Thus, for example, the base station can reliably know when to send a signal to the user equipment notifying the user equipment of the transmission time, and also in some implementations, when to resend the signal to the user equipment (to increase the likelihood that the user equipment will learn that the transmission time is ongoing).

[0008] In various implementations, the base station may send a wake-up signal (WUS), a signal indicating that the transmission time has begun, or a signal indicating the structure of the transmission time (e.g., COT duration) to the user equipment to notify the user equipment of the transmission time and trigger a change in the transmission mode to the control channel opportunity. In some implementations where the base station retransmits the signal one or more times to ensure reception by the user equipment, the base station updates the transmission time information in the signal in each retransmission. For example, the initial transmission of the signal may indicate the full duration of the COT, while the retransmission of the signal may instead indicate the amount of time remaining in the COT when the retransmission occurs.

[0009] In some implementations, the base station (e.g., via one or more radio resource control (RRC) messages, one or more media access control (MAC) control elements, one or more downlink control information (DCI), etc.) configures the user equipment to monitor the control channel according to two different modes of control channel timing, and the user equipment selectively performs the pre-transmission mode or the transmission mode by combining the timings of the two modes in different ways. For example, the user equipment may perform the pre-transmission mode by monitoring the control channel during all timings of the first mode and all timings of the second mode, and then change to the transmission mode by monitoring the control channel only during the timings of the first mode but not the second mode. As another example, the user equipment may perform the pre-transmission mode by monitoring the control channel during all timings of the first mode, and then change to the transmission mode by monitoring the control channel only during those timings of the first and second modes that overlap with each other. As yet another example, the user equipment may perform the pre-transmission mode by monitoring the control channel only during the timings of the first mode, and then change to the transmission mode by monitoring the control channel during all timings of the first mode and all timings of the second mode.

[0010] In some implementations, the base station configures the user equipment to use different time-frequency resources when monitoring the control channel during the timings of the different modes. In the above example, for example, the base station can configure the user equipment to use a first time-frequency resource (e.g., a first search space configuration) when monitoring during the timings of the first mode, and to use a different second time-frequency resource (e.g., a second search space configuration) when monitoring during the timings of the second mode. Additionally or alternatively, in some implementations, and in order to increase the granularity with which the base station can send control channel information, the base station sends a wake-up signal to the user equipment to cause the user equipment to monitor the control channel at a single additional timing that does not overlap with any timing of the first or second mode.

[0011] An example embodiment of these techniques is a method of obtaining control channel information from a base station communicating with a user equipment via a shared carrier. The method can be implemented in a user equipment using processing hardware and includes: monitoring a control channel on a shared carrier according to a pre-transmission pattern of control channel opportunities; while monitoring the control channel using the pre-transmission pattern, receiving a signal from the base station via the shared carrier indicating a transmission time during which the shared carrier is available to the base station; and in response to receiving the signal, during the transmission time, monitoring the control channel on the shared carrier according to a transmission pattern of control channel opportunities, the transmission pattern of the control channel opportunities being different from the pre-transmission pattern but including at least one control channel opportunity that overlaps with a control channel opportunity of the pre-transmission pattern.

[0012] Another example embodiment of the techniques is a user device comprising processing hardware and configured to perform the above method.

[0013] Another example embodiment of these techniques is a method of providing control channel information to a user equipment communicating with a base station via a shared carrier. The method can be implemented in a base station using processing hardware and includes: using a channel access process to determine that the shared carrier is available to the base station within a transmission time; at least by sending one or more messages to the user equipment via the shared carrier, causing the user equipment to monitor the control channel on the shared carrier according to a pre-transmission mode of the control channel opportunity before the transmission time, and monitor the control channel on the shared carrier according to a transmission mode of the control channel opportunity during the transmission time. The transmission mode is different from the pre-transmission mode, but includes at least one control channel opportunity that overlaps with the control channel opportunity of the pre-transmission mode.

[0014] Another example embodiment of the techniques is a base station comprising processing hardware and configured to perform the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram of an example wireless communication network that implements the scheduling and channel monitoring techniques of the present disclosure;

[0016] Figure 2 depicts an example message sequence according to which a base station configures two modes for a UE and provides an indication of when the UE switches from monitoring a control channel according to a logical union of a first mode and a second mode to monitoring a control channel according to only the first mode;

[0017] Figure 3 can correspond to Figure 2 A timing diagram of an example pattern of a message sequence;

[0018] Figure 4An example message sequence is depicted according to which a base station provides to a UE a plurality of indications of transmission times during which a shared carrier is available to the base station;

[0019] Figure 5 An example message sequence is depicted according to which a base station configures two partially overlapping modes for a UE and provides an indication of a time for the UE to switch from monitoring a control channel according to a first mode to monitoring a channel according to a logical intersection of the first mode and the second mode;

[0020] Figure 6 can correspond to Figure 5 A timing diagram of an example pattern of a message sequence;

[0021] Figure 7 An example message sequence is depicted according to which a base station configures a UE with a first mode and a second mode that is a subset of the first mode, and provides an indication of when the UE switches from monitoring a control channel according to the first mode to monitoring a channel according to the second mode;

[0022] Figure 8 can correspond to Figure 7 A timing diagram of an example pattern of a message sequence;

[0023] Fig. 9 An example message sequence is depicted according to which a base station configures two modes for a UE and provides an indication of when the UE switches from monitoring a control channel according to a first mode to monitoring a control channel according to a logical union of the first mode and a second mode;

[0024] Fig.10 can correspond to Fig. 9 A timing diagram of an example pattern of a message sequence;

[0025] Fig.11 depicts an example message sequence according to which a base station configures two partially overlapping modes for a UE and provides an indication of a time for the UE to switch from monitoring a control channel according to a first mode to monitoring a channel according to a logical union of the two modes;

[0026] Fig.12 can correspond to Fig.11 A timing diagram of an example pattern of a message sequence;

[0027] Fig.13 An example message sequence is depicted according to which a base station configures a second mode and a first mode that is a subset of the second mode for a UE and provides an indication of a time when the UE switches from monitoring a control channel according to the first mode to monitoring a channel according to a logical union of the two modes;

[0028] Fig.14can correspond to Fig.13 A timing diagram of an example pattern of a message sequence;

[0029] Fig.15 Yes, you can Figure 1 A flowchart of an example method implemented in a user equipment for monitoring a control channel; and

[0030] Fig.16 Yes, you can Figure 1 A flowchart of an example method implemented in a base station for configuring a user equipment to monitor a control channel. DETAILED DESCRIPTION

[0031] Using the techniques of the present 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 delays in starting transmissions (e.g., uplink transmissions that require configuration of the UE via the control channel). As the term is used herein, a "carrier" can be any type of spectrum or frequency band that corresponds to at least one channel in a given radio access network. In addition, as used herein, a "shared" carrier can be an unlicensed carrier shared by different radio access networks and / or technologies, or a carrier that is shared in some other manner and / or for some other reason (e.g., a carrier that is shared only between multiple devices of a single radio access network).

[0032] The following mainly refers to 5G NR technology, and more specifically, to the operation of a 5G NR network on an unlicensed carrier (i.e., NR-U operation) to discuss these technologies. However, the techniques of the present disclosure may be applied to other radio access technologies and / or to other types of shared carriers (e.g., a licensed band shared by devices of a single radio access network). In the case of a licensed band, a channel access procedure of the type described below may or may not be performed.

[0033] First refer to Figure 1 , the wireless communication network 100 includes a UE 102, which can be any suitable device capable of wireless communication, as further discussed below. The wireless communication network 100 also includes a base station 104 associated with an NR-U cell 106 and connected (directly or indirectly) to a 5G core network (5GC) 110. The base station 104 can operate as, for example, a 5G Node B (gNB), a distributed unit gNB (gNB-DU), or an integrated access backhaul (IAB) node. Although Figure 1 Base station 104 is depicted as serving only cell 106, it should be understood that base station 104 may also cover Figure 1In general, wireless communication network 100 may include any number of base stations, and each of the base stations may cover one, two, three, or any other suitable number of cells.

[0034] 5G NR UEs (including UE 102) operating in cell 106 can utilize unlicensed carriers and portions of the radio spectrum that are exclusively allocated to the service provider operating base station 104 and 5GC 110. When exchanging data using the 5G NR air interface, UE 102 and base station 104 can share the unlicensed carrier with other devices of other radio access networks. For example, other UEs ( Figure 1 The UE (not shown) may be a subscriber of a service provider operating the base station 104 and the 5GC 110 and may be able to communicate with the base station 104 via an unlicensed carrier. In addition, or alternatively, other UEs utilizing an unlicensed carrier may communicate with a base station or network node other than the base station 104 using a different radio access technology. Figure 1 An example of such a scenario is depicted in which UE 102 and base station 104 coexist with access point (AP) 112. When operating in a wireless local area network (WLAN) in accordance with one of the IEEE 802.11 standards, AP 112 can utilize a spectrum that includes or is included within at least a portion of an unlicensed carrier. AP 112 can be configured to communicate with Figure 1 The UE 102 and the base station 104 may communicate with one or more other devices not shown in the figure, such as, for example, other UEs. In other implementations and / or scenarios, the UE 102 and the base station 104 may also coexist with devices operating according to other radio access technologies or alternatively coexist with devices operating according to other radio access technologies. In yet another implementation and / or scenario, the base station 104 is not connected to the 5GC 110 and may operate as an AP (e.g., similar to the AP 112). Thus, for example, the wireless communication network 100 may omit the 5GC 110, or may use the 5GC 110 only in certain scenarios.

[0035] The UE 102 is equipped with processing hardware 120, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, the processing hardware 120 may include a dedicated processing unit, such as, for example, a wireless communication chipset. The processing hardware 120 includes a control channel monitoring module 122, and the memory of the processing hardware 120 stores a monitoring configuration 124. The control channel monitoring module 122 may be implemented using any suitable combination of hardware, software, and / or firmware. In one example implementation, the control channel monitoring module 122 includes an instruction set defining corresponding components of the operating system of the UE 102, and one or more CPUs of the processing hardware 120 execute these instructions to perform channel monitoring functions. In another implementation, the control channel monitoring module 122 is implemented using firmware as part of a wireless communication chipset.

[0036] In operation, the control channel monitoring module 122 monitors the control channel according to the monitoring configuration 124 provided by the gNB 104 to the UE 102. In some implementations and / or scenarios, the control channel monitoring module 122 monitors the PDCCH. However, in other implementations and / or scenarios, the control channel monitoring module 122 monitors the group common-PDCCH (GC-PDCCH). The monitoring configuration 124 may include a description of a pattern of control channel opportunities and a corresponding search space configuration. Each "control channel opportunity" may represent a time or time window when the gNB 104 is able (i.e., according to the specifications of the wireless communication network) but is not required to send control channel information to the UE 102. As used herein, a "pattern" of control channel opportunities refers to a time distribution of control channel opportunities that repeat once per time unit, where the time unit is fixed and can be any suitable length or duration depending on the implementation (e.g., a time slot, a set of N consecutive time slots, a subframe, etc.). As a simple example, the pattern may include only a single control channel opportunity at the beginning of each time slot. Depending on the implementation, the pre-transmission mode may include more control channel opportunities per time unit than the transmission mode (e.g., to provide a finer time granularity at which the gNB 104 can send control channel information to the user equipment), fewer control channel opportunities per time unit than the transmission mode, or the same number of control channel opportunities per time unit (albeit with a different distribution and / or time-shift).

[0037] The base station 104 is equipped with processing hardware 130, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, the processing hardware 130 may include a dedicated processing unit, such as a wireless communication chipset, for example. Figure 1 The processing hardware 130 in the example implementation of includes a channel access module 132 , a resource allocation unit 134 , and a COT signal controller 136 .

[0038] The channel access module 132 performs a channel access procedure, such as an LBT procedure, to obtain access to a shared carrier in the NR-U cell 106. When the channel access procedure is successful, the channel access module 132 determines that the gNB 104 has acquired or established a COT and can therefore send various signals during the COT. The resource allocation unit 134 allocates radio resources (i.e., time-frequency resources) and configuration parameters, such as a monitoring mode for control channel (e.g., PDCCH) timing, a control resource set (CORESET), a search space, etc. to the UE 102. As further discussed below, the UE 102 can combine these control channel monitoring modes in various ways to generate a pre-transmission monitoring mode and a transmission monitoring mode (or more specifically, in this implementation, a pre-COT monitoring mode and a COT monitoring mode). The COT signal controller 136 determines when the gNB 104 sends an indication to the UE 102 that the gNB 104 has acquired a COT. In some implementations, the COT signal controller 136 also determines which format the gNB 104 should utilize for the indication. Example functionality of components 132, 134, and 136 is discussed in greater detail below with reference to various example scenarios and monitoring modes.

[0039] To keep it simple, Figure 1 Various components of UE 102 and base station 104 are not depicted. In addition to the above components, for example, UE 102 and base station 104 include corresponding transceivers, which include various hardware, firmware and / or software components configured to send and receive wireless signals. Processing hardware 120 and processing hardware 130 can send commands and exchange information with corresponding transceivers as needed to perform various connection establishment procedures, perform various RRC or mobility management (MM), or communicate with other network elements, etc.

[0040] Figure 2-Figure 14 Several example configurations are shown according to which UE 102 may monitor PDCCH. In general, UE 102 monitors PDCCH during at least two time intervals: before gNB 104 obtains access to a shared carrier and after UE 102 receives an indication that gNB 104 has obtained access to a shared carrier. UE 102 monitors PDCCH associated with a shared carrier during these two intervals according to different patterns of PDCCH occasions, but there is some overlap in the occasions of these patterns. Typically, in at least some implementations, the lower frequency occasions cause UE 102 to consume less power by reducing the number of opportunities for gNB 104 to send control channel information to UE 102.

[0041] First refer to Figure 2 and Figure 3 , the gNB 104 in the example scenario 200 determines to configure the UE 102 to monitor the PDCCH according to a first mode 300 of PDCCH opportunities and a second mode 302 of PDCCH opportunities (202). The gNB 104 indicates the first mode 300 and the second mode 302 to the UE 102 (204), for example, by sending one or more configuration messages to the UE 102 via a shared carrier, as discussed further below. Generally, the UE 102 uses the modes 300 and 302 to generate a dynamic monitoring schedule 304, as discussed in further detail below. In the example mode 300, the PDCCH opportunity 312 occurs at the beginning of each respective time unit 310, where each time unit 310 can be a time slot, a set of N consecutive time slots, a subframe, etc. In the example mode 302, the PDCCH opportunity 314 occurs at or near the midpoint of each respective time unit 310. In general, PDCCH opportunities 312 and 314 may occur at any time or multiple times within time unit 310. Although opportunities 312 and 314 are referred to herein as PDCCH opportunities, the techniques of this disclosure may also be applied to GC-PDCCH opportunities or other types of control channel opportunities.

[0042] Continue to refer to Figure 2 and Figure 3 , schedule 304 covers pre-COT 320 as well as COT 322 itself, where pre-COT 320 is the time interval before gNB 104 establishes COT 322. Figure 3 , COT 322 begins at time 324 and ends at time 326. During pre-COT 320, UE 102 monitors PDCCH according to a pre-COT pattern 330 that includes all PDCCH opportunities of patterns 300 and 302 (206). In other words, UE 102 during this period monitors PDCCH according to a logical union of patterns 300 and 302. During each time unit 310 of pre-COT 320, UE 102 monitors PDCCH during both opportunity 312 and opportunity 314. After gNB 104 (e.g., using channel access module 132) obtains access to the shared carrier to establish COT 322 (208), gNB 104 indicates to UE 102 that COT 322 has begun (210). In response to the indication 210 , and during the COT 322 , the UE 102 monitors the PDCCH according to the pattern 300 , and no longer monitors the PDCCH according to the pattern 302 ( 212 ).

[0043] To indicate (210) to the UE 102 that the COT 322 has begun, the gNB 104 may send a WUS, a signal generally indicating that the COT 322 has begun (e.g., a “COT indicator”), a signal indicating the structure of the COT 322 (e.g., the duration of the COT 322), or another suitable signal (e.g., any suitable signal generated by the COT signal controller 136) indicating that the UE 102 is to stop monitoring according to the pattern 302. Depending on the implementation, the gNB 104 may send the WUS or other signal at time 324, during the first PDCCH opportunity of the pattern 300 or 302 that occurs after time 324 (in this example, opportunity 314a), or at another suitable time. In some implementations and / or scenarios, the gNB 104 sends the signal indicating that the COT 322 has begun only once. In other implementations and / or scenarios, the gNB 104 sends such a signal multiple times in order to increase the probability that the UE 102 receives the signal and therefore knows when to stop monitoring according to the pattern 302. In some implementations, the gNB 104 indicates (210) the COT 322 duration in a broadcast message. Several example techniques for indicating (210) that the COT 322 has begun are discussed in more detail below.

[0044] exist Figure 3 In the example scenario reflected in FIG. 3 , COT 322 occurs during time unit 310 a after opportunity 312 of mode 300 within time unit 310 a has occurred, but before opportunity 314 of mode 302 within time unit 310 a (i.e., Figure 3 314a) occurs before the occurrence of the timing 314a in the COT. The UE 102 in this implementation thus monitors the PDCCH during the specific timing 314a, but does not monitor the timing 314 starting from the next time unit 310b for the duration of the COT 322. For clarity, Figure 3 The first time 314b of the pattern 302 is shown with dashed outline, during which the UE 102 does not monitor the PDCCH. Figure 3 314b), where UE 102 fails to receive a WUS or other signal from gNB 104 indicating that COT 322 has begun, UE 102 will monitor the PDCCH during opportunity 314b and in each subsequent opportunity 314 in mode 302.

[0045] In another implementation, after UE 102 receives an indication that COT 322 has begun, UE 102 continues to monitor PDCCH according to both mode 300 and mode 302 for a certain amount of time, or a certain number of PDCCH opportunities, etc., which may be dynamically configured by gNB 104 or it may be part of the corresponding 3GPP specification. Thereafter, but still during COT 322, UE 102 transitions to monitoring PDCCH only during opportunities 312 of mode 300. In yet another implementation, UE 102 switches from the logical union of modes 300, 302 to mode 302 only (rather than mode 300 only) after receiving an indication from gNB 104.

[0046] Thus, the UE 102 monitors the PDCCH according to the pattern 300, regardless of whether the UE 102 has received an indication that the COT 322 has begun, but utilizes the pattern 302 only during the pre-COT 320 (or possibly, as described above, also for some relatively short time at the beginning of the COT 322). The timing 312 accordingly defines the overlap between the pre-COT pattern 330 used by the UE 102 during the pre-COT 320 and the COT pattern 332 used by the UE 102 during the COT 322. The pre-COT pattern 330 and the COT pattern 332 in this example overlap only in a single PDCCH opportunity per time unit 310 (at the beginning of each time unit 310). More generally, however, the pre-COT pattern 330 and the COT pattern 332 may overlap in any suitable number of PDCCH opportunities per time unit 310, and at any position or multiple positions within the time unit 310.

[0047] The overlapping opportunities between the pre-COT mode 330 and the COT mode 332 allow the gNB 104 to be aware of at least some of the times during which the UE 102 should monitor the PDCCH, regardless of whether the UE 102 has received a signal from the gNB 104, and regardless of whether the UE 102 has switched from the pre-COT mode 330 to the COT mode 332. This is particularly important because the UE 102 may miss signals indicating that the gNB 104 has established the COT 322, and because the UE 102 does not (in at least some implementations) acknowledge receipt of such signals. Thus, the gNB 104 may generally be unaware of whether the UE 102 is aware that the COT 322 has begun. In some implementations, the gNB 104 may send one or more additional indications via the PDCCH that the COT 322 has begun during one of the opportunities 312 (again, because the gNB 104 is aware that the UE 102 is monitoring the PDCCH according to the mode 300 in both the pre-COT mode 330 and the COT mode 332). Alternatively or additionally, gNB 104 may utilize the fact that UE 102 is monitoring PDCCH at least according to mode 300 to send control information to UE 102 at one or more of opportunities 312.

[0048] Furthermore, because COT mode 332 includes fewer opportunities per time unit 310 than pre-COT mode 330, transitioning from pre-COT mode 330 to COT mode 332 allows UE 102 to save power compared to if UE 102 monitored PDCCH at a higher frequency during both pre-COT 320 and COT 322. Still further, because pre-COT mode 330 includes more opportunities per time unit 310 than COT mode 332, gNB 104 has more opportunities to send information on PDCCH to UE 102 during pre-COT 320. After COT 322 terminates, UE 102 may resume monitoring according to pre-COT mode (not shown), another mode, or no mode at all, depending on the embodiment.

[0049] Additionally or alternatively, gNB 104 may transmit DCI on the PDCCH during one of the opportunities 312, which may include downlink assignment information indicating that UE 102 may receive on a physical downlink shared channel (PDSCH) or uplink grant indicating that UE 102 may transmit on a physical uplink shared channel (PUSCH). Thus, more opportunities for gNB 104 to transmit on the PDCCH may result in more opportunities for UE 102 to transmit or receive higher layer messages or data.

[0050] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 should begin monitoring according to mode 302, or a signal indicating that COT 322 has ended. In addition to monitoring PDCCH according to mode 300, UE 102 may monitor PDCCH according to mode 302 in response to the signal. UE 102 may begin monitoring PDCCH according to mode 302 immediately after receiving the signal, or may begin monitoring PDCCH according to mode 302 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and knows the end of COT 322 (e.g., according to the following for Figure 4 If the COT structure described is indicated), the UE 102 starts monitoring modes 300 and 302 after the end of COT 322.

[0051] Now refer to Figure 4 , the gNB 104 in example scenario 400 provides multiple indications of COTs (e.g., COT 322) to the UE 102 during which the shared carrier is available to the gNB 104. As discussed above, the UE 102 in some cases may miss the indication that the gNB 104 has established the COT, and the UE 102 may not acknowledge to the gNB 104 when the UE 102 has successfully received such an indication. Figure 4 In an implementation of the present invention, gNB 104 sends the indication multiple times to increase the probability that UE 102 is aware of the COT. However, this alone may not provide UE 102 with enough information to know when the COT will end (e.g., time 326), and therefore UE 102 may not know how long to monitor the PDCCH according to the COT mode (e.g., mode 332).

[0052] Thus, to ensure that the UE 102 correctly identifies the end of the COT, the gNB 104 may include an indication of the remaining duration of the COT in each of the plurality of transmissions. Specifically, immediately or shortly after the gNB 104 establishes the COT (408a), the gNB 104 indicates a first duration of the COT to the UE 102 (410a), e.g., by sending a first COT structure indication to the UE 102 via a shared carrier. The first duration may be the entire duration of the COT, which may be determined by the gNB 104 when the gNB 104 is granted access to the shared channel. At a later time, the gNB 104 determines the remaining (shorter) duration of the COT (408b) and indicates the remaining duration to the UE 102 (410b), e.g., by sending a second COT structure indication to the UE 102 via a shared carrier. The gNB 104 may determine the remaining duration by subtracting a current timer value (e.g., the value of a timer started by the gNB 104 at the start of the COT) from the original / full duration of the COT. gNB 104 may indicate the remaining duration of the COT using any suitable format and parameters, such as an end time relative to the current time unit (e.g., time 326), the number of remaining time units, the number of remaining microseconds, etc.

[0053] Although the gNB 104 in example scenario 400 indicates the COT duration twice, in general, the gNB 104 may provide any suitable number of indications of the remaining COT time to the UE 102.

[0054] Figure 5 Another example scenario 500 is shown in which the gNB 104 configures two partially overlapping patterns for the UE 102, and the UE 102 monitors the PDCCH using these partially overlapping patterns according to the pre-COT mode and the COT mode. Figure 2 102 switches from monitoring PDCCH according to one of the modes to monitoring PDCCH according to the logical intersection of the two modes. Likewise, the overlap of the timings of the pre-COT and COT modes allows the gNB 104 to rely on at least one timing per time unit where the UE 102 should monitor PDCCH, regardless of whether the UE 102 has received a signal from the gNB 104 and regardless of whether the UE 102 has switched from the pre-COT mode to the COT mode.

[0055] Reference Figure 5 and Figure 6 In both cases, gNB 104 first determines to configure UE 102 to monitor PDCCH according to a first mode 600 of PDCCH timing and a second mode 602 of PDCCH timing (502). Figure 6As can be seen in FIG. 6 , patterns 600 and 602 partially overlap, where an opportunity 612a of pattern 600 coincides with an opportunity 614a of pattern 602. Thus, an overlapping opportunity occurs once every two consecutive time units 610. In other implementations and / or scenarios, gNB 104 may select or set monitoring patterns 600 and 602 such that the overlapping opportunities are less than Figure 6 More or less frequent as shown.

[0056] gNB 104 indicates patterns 600 and 602 to UE 102 (504), for example, by sending one or more configuration messages to UE 102 via a shared carrier, as discussed further below. UE 102 uses patterns 600 and 602 to generate a dynamic monitoring schedule 604. Similar to Figure 3 Schedule 304 of gNB 104, schedule 604 covers pre-COT 620 and COT 622 itself, where pre-COT 620 is the time interval before gNB 104 establishes COT 622. Figure 6 As seen in FIG. 6 , COT 622 begins at time 624 and ends at time 626. During pre-COT 620, UE 102 monitors PDCCH according to pre-COT mode 630 (506). Also similar to Figure 3 In the scenario of , the pre-COT mode 630 is equivalent to the first mode 600. In an alternative implementation, the pre-COT mode 630 is the logical union of the modes 600 and 602, and the COT mode 632 is the logical intersection of the modes 600 and 602.

[0057] Next, gNB 104 establishes COT 622 (508) and indicates to UE 102 that COT 622 has begun (510), or that the logical intersection of patterns 600 and 602 is to be monitored. In response to the indication 510, and during COT 622, UE 102 monitors PDCCH according to COT pattern 632 (which is the logical intersection of patterns 600 and 602) (512). In other words, UE 102 monitors PDCCH only during those PDCCH opportunities of pattern 600 that overlap with PDCCH opportunities of pattern 602, and vice versa. For example, PDCCH opportunity 612b of pattern 600 coincides with PDCCH opportunity 614b of pattern 602, and therefore UE 102 monitors PDCCH during the overlapping opportunities. On the other hand, UE 102 does not monitor PDCCH during opportunity 612c of pattern 600 because opportunity 612c does not coincide with any opportunity of pattern 602, and UE 102 does not monitor PDCCH during opportunity 614c of pattern 602 because opportunity 614c does not coincide with any opportunity of pattern 600.

[0058] The overlapping timings between pre-COT mode 630 and COT mode 632 allow gNB 104 to know at least some of the time during which UE 102 should monitor PDCCH, regardless of whether UE 102 has received a WUS or other signal from gNB 104, and regardless of whether UE 102 has switched from pre-COT mode 630 to COT mode 632. gNB 104 can utilize this knowledge when resending a signal indicating COT 622 to UE 102, and / or when sending control information to UE 102, as described above in conjunction with Figure 3 and Figure 4 discussed.

[0059] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 is to begin monitoring PDCCH according to mode 600 instead of the logical intersection of modes 600 and 602, or a signal indicating that COT 622 has ended. Thereafter, UE 102 monitors PDCCH according to mode 600 in response to the signal. UE 102 may begin monitoring PDCCH according to mode 600 immediately upon receiving the signal, or may begin monitoring PDCCH according to mode 600 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and knows the end of COT 622 (e.g., according to the above for Figure 4 If the COT structure described in the specification indicates that the UE starts monitoring mode 600 after the end of COT 622.

[0060] Figure 7 Another example scenario 700 is shown in which the gNB 104 configures two modes for the UE 102, one of which is a subset of the other mode, and the UE 102 uses these modes to monitor the PDCCH according to the pre-COT mode and the COT mode. Figure 7 and Figure 8 They are Figure 5 and Figure 6 , because the COT mode is a subset of the pre-COT mode.

[0061] Reference Figure 7 and Figure 8 In both cases, gNB 104 first determines to configure UE 102 to monitor PDCCH according to a first mode 800 of PDCCH timing and a second mode 802 of PDCCH timing (702). In this example, mode 802 is a subset of mode 800. Figure 8As shown in FIG. 8 , in each time unit 810 , an opportunity 814 of pattern 802 coincides with a first opportunity 812 of pattern 800 . However, pattern 800 also includes a second opportunity in each time unit 810 that is not present in pattern 802 .

[0062] gNB 104 indicates patterns 800 and 802 to UE 102 (704), for example, by sending one or more configuration messages to UE 102 via a shared carrier, as discussed further below. UE 102 uses patterns 800 and 802 to generate a dynamic monitoring schedule 804. Similar to Figure 3 Schedule 304, schedule 804 covers pre-COT 820 and COT 822 itself, pre-COT 820 is the time interval before gNB 104 establishes COT 822. Figure 8 As seen in FIG. 8 , COT 822 starts at time 824 and ends at time 826. During pre-COT 820, UE 102 monitors PDCCH according to pre-COT pattern 830 (706). In this scenario, pre-COT pattern 830 is pattern 800 that includes exactly every opportunity of pattern 802 and is therefore equivalent to the logical union of patterns 800 and 802.

[0063] Next, gNB 104 establishes COT 822 (708) and indicates to UE 102 that COT 822 has been established or that PDCCH is to be monitored according to mode 802 (710). In response to the indication 710, and during COT 822, UE 102 monitors PDCCH according to COT mode 832 (which is mode 802) (712). Because COT mode 832 is a subset of mode 800, COT mode 832 is equivalent to the logical intersection of modes 800 and 802.

[0064] The overlapping timings between pre-COT mode 830 and COT mode 832 allow gNB 104 to know at least some of the time during which UE 102 should monitor PDCCH, regardless of whether UE 102 has received a WUS or other signal from gNB 104, and regardless of whether UE 102 has switched from pre-COT mode 830 to COT mode 832. gNB 104 can utilize this knowledge when resending a signal indicating COT 822 to UE 102, and / or when sending control information to UE 102, as described above in conjunction with Figure 3 and Figure 4 discussed.

[0065] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 is to begin monitoring PDCCH according to mode 800 instead of mode 802, or a signal indicating that COT 822 has ended. UE 102 monitors PDCCH according to mode 800 in response to the signal. UE 102 may begin monitoring PDCCH according to mode 800 immediately upon receiving the signal, or may begin monitoring PDCCH according to mode 800 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and is aware of the end of COT 822 (e.g., as described above for Figure 4 If the COT structure described is indicated), the UE starts monitoring mode 800 after the end of COT 822.

[0066] In the above example, UE 102 reduces the frequency of monitoring PDCCH by switching from pre-COT mode to COT mode. However, in other implementations, UE 102 may begin monitoring PDCCH more frequently (rather than less frequently) during COT. This alternative approach retains the advantage that if UE 102 has missed an indication that COT has begun and therefore has not switched from pre-COT mode to COT mode, gNB 104 still knows that UE 102 is monitoring PDCCH at least during overlapping occasions (i.e., occasions of COT mode that overlap with occasions of pre-COT mode). In addition, in those cases where UE 102 does not receive an indication that COT has begun and therefore continues to monitor PDCCH according to pre-COT mode, the reduced frequency of occasions in pre-COT mode allows UE 102 to save power.

[0067] For example, refer to Fig. 9 and Fig.10 , gNB 104 first determines to configure UE 102 to monitor PDCCH according to a first mode 1000 of PDCCH timing and a second mode 1002 of PDCCH timing (902). gNB 104 indicates modes 1000 and 1002 to UE 102 (904), for example, by sending one or more configuration messages to UE 102 via a shared carrier, as discussed further below. UE 102 uses these modes 1000 and 1002 to generate a dynamic monitoring schedule 1004. Similar to Figure 3 Schedule 304, which covers pre-COT 1020 and COT 1022 itself, where pre-COT 1020 is the time interval before gNB 104 establishes COT 1022. Fig.10As seen in FIG. 1 , COT 1022 starts at time 1024 and ends at time 1026. During pre-COT 1020, UE 102 monitors PDCCH (906) according to a pre-COT mode 1030, which is equivalent to first mode 1000 in this example.

[0068] Next, gNB 104 establishes COT 1022 (908) and indicates to UE 102 that COT 1022 has begun (910). In response to the indication 910, and during COT 1022, UE 102 monitors the PDCCH by continuing to monitor the PDCCH according to the first mode 1000 and also starting to monitor the PDCCH according to the second mode 1002 (912). Thus, COT mode 1032 in this example is the logical union of modes 1000 and 1002.

[0069] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 is to stop monitoring PDCCH according to mode 1002, or a signal indicating that COT 1022 has ended. UE 102 monitors PDCCH according to mode 1000 in response to the signal. UE 102 may stop monitoring PDCCH according to mode 1002 immediately upon receiving the signal, or may stop monitoring PDCCH according to mode 1002 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and is aware of the end of COT 1022 (e.g., as described above for Figure 4 If the COT structure described is indicated), the UE 102 stops monitoring mode 1002 after the end of COT 1022.

[0070] Next, refer to Fig.11 and Fig.12 , gNB 104 first determines to configure UE 102 to monitor PDCCH according to a first mode 1200 of PDCCH timing and a second mode 1202 of PDCCH timing (1102). Fig.12 As can be seen in FIG. 1 , patterns 1200 and 1202 partially overlap, where an opportunity 1212a of pattern 1200 coincides with an opportunity 1214a of pattern 1202. Thus, in this example, an overlapping opportunity occurs once every two consecutive time units 1210. In other implementations and / or scenarios, gNB 104 may select or set monitoring patterns 1200 and 1202 such that the overlapping opportunities are less than 100%. Fig.12 More or less frequent as shown.

[0071] The gNB 104 indicates the patterns 1200 and 1202 to the UE 102 (1104), for example, by sending one or more configuration messages to the UE 102 via a shared carrier, as discussed further below. The UE 102 uses these patterns 1200 and 1202 to generate a dynamic monitoring schedule 1204. Similar to Figure 3 Schedule 304, which covers pre-COT 1220 and COT 1222 itself, where pre-COT 1220 is the time interval before gNB 104 establishes COT 1222. Fig.12 As seen in FIG. 12, COT 1222 starts at time 1224 and ends at time 1226. During pre-COT 1220, UE 102 monitors PDCCH (1106) according to a pre-COT mode 1230, which is equivalent to first mode 1200 in this example.

[0072] Next, gNB 104 establishes COT 1222 (1108) and indicates to UE 102 that COT 1222 has begun (1110). In response to the indication 1110, and during COT 1222, UE 102 monitors the PDCCH (1112) by continuing to monitor the PDCCH according to the first mode 1200 and also starting to monitor the PDCCH according to the second mode 1202. Thus, COT mode 1232 in this example is the logical union of modes 1200 and 1202. In another example, COT mode 1232 is second mode 1202.

[0073] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 is to stop monitoring PDCCH according to mode 1202, or a signal indicating that COT 1222 has ended. UE 102 monitors PDCCH according to mode 1200 in response to the signal. UE 102 may stop monitoring PDCCH according to mode 1202 immediately upon receiving the signal, or may stop monitoring PDCCH according to mode 1202 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and is aware of the end of COT 1222 (e.g., as described above for Figure 4 If the COT structure described is indicated), the UE 102 stops monitoring mode 1202 after the end of COT 1222.

[0074] Next, refer to Fig.13 and Fig.14, gNB 104 first determines to configure UE 102 to monitor PDCCH according to a first mode 1400 of PDCCH timing and a second mode 1402 of PDCCH timing (1302), wherein mode 1400 is a subset of mode 1402. Fig.14 As shown in FIG. 14 , in each time unit 1410 , an opportunity 1412 of pattern 1400 coincides with a first opportunity 1414 of pattern 1402 . However, pattern 1402 includes a second opportunity in each time unit 1410 that is not present in pattern 1400 .

[0075] gNB 104 indicates patterns 1400 and 1402 to UE 102 (1304). UE 102 uses patterns 1400 and 1402 to generate dynamic monitoring schedule 1404. Similar to Figure 3 Schedule 304, which covers pre-COT 1420 and COT 1422 itself, where pre-COT 1420 is the time interval before gNB 104 establishes COT 1422. Fig.14 As seen in FIG. 14 , COT 1422 begins at time 1424 and ends at time 1426. During pre-COT 1420, UE 102 monitors PDCCH (1306) according to a pre-COT pattern 1430, which is first pattern 1400 in this example.

[0076] Next, gNB 104 establishes COT 1422 (1308) and indicates to UE 102 that COT 1422 has begun (1310). In response to the indication 1310, and during COT 1422, UE 102 monitors PDCCH (1312) by continuing to monitor according to first mode 1400 and also starting to monitor according to second mode 1402 (i.e., by monitoring according to the logical union of modes 1400 and 1402). Because mode 1400 is a subset of mode 1402, COT mode 1432 is also equivalent to mode 1402.

[0077] In some cases, gNB 104 may send a signal to UE 102 indicating that UE 102 is to stop monitoring PDCCH according to mode 1402, or a signal indicating that COT 1422 has ended. UE 102 monitors PDCCH according to mode 1400 in response to the signal. UE 102 may stop monitoring PDCCH according to mode 1402 immediately upon receiving the signal, or may stop monitoring PDCCH according to mode 1402 after a certain amount of time has passed after receiving the signal. For example, the signal may be a DCI. In other cases, if UE 102 does not receive the signal and is aware of the end of COT 1422 (e.g., as described above for Figure 4If the COT structure described in the description indicates that the UE 102 stops monitoring the PDCCH according to mode 1402 after the end of COT 1422.

[0078] Now refer to the above discussion Figure 2-Figure 14 The example scenarios are used to discuss various more specific implementation methods.

[0079] In some implementations and / or scenarios, the control channel monitored by UE 102 may be a GC-PDCCH instead of a PDCCH. When the control channel is a GC-PDCCH, gNB 104 may configure UE 102 with a specific group common-radio network temporary identifier (GC-RNTI) that UE 102 may use to monitor GC-PDCCH. For example, UE 102 may monitor GC-PDCCH during PDCCH opportunities according to pre-COT mode 330, 630, 830, 1030, 1230, or 1430. Alternatively, UE 102 may monitor GC-PDCCH according to mode 300, 600, 800, 1000, 1200, or 1400, or according to mode 302, 602, 802, 1002, 1202, or 1402. As another example, gNB 104 may configure GC-PDCCH opportunities specifically for UE 102 using a SearchSpace information element (IE) or another suitable indication of a search space configuration.

[0080] exist Figure 2-Figure 14 In an example scenario, gNB 104 indicates a first mode and a second mode (204, 504, 704, 904, 1104, 1304) to UE 102 using one or more configuration messages. In one implementation, gNB 104 sends an RRC message indicating the mode, such as, for example, RRC Reconfiguration, RRC Setup, or RRC Resume. The configuration message may also include at least one DCI and / or MAC control element (CE). For each of modes 300 / 302, 600 / 602, 800 / 802, 1000 / 1002, 1200 / 1202, and 1400 / 1402, the DCI, MAC CE, or other configuration message may indicate the separation in time between consecutive PDCCH opportunities for each mode, the duration of each PDCCH opportunity in the mode, etc. In response to the one or more configuration messages, UE 102 may send one or more messages, such as, for example, a MAC configuration CE. In another implementation and / or scenario, UE 102 sends a physical uplink control channel (PUCCH) indication to gNB 104 in response to one or more configuration messages from gNB 104.

[0081] In addition, the one or more configuration messages may include a CORESET to indicate the time-frequency resources allocated to the UE 102. For example, the (one or more) configuration messages may indicate certain frequency resources (e.g., one or more frequency ranges) for a certain time duration (e.g., one, two, or three OFDM symbols) during which the UE 102 is to search for DCI. The gNB 104 may send the configuration to the UE 102 using, for example, a ControlResourceSet IE. The gNB 104 in an example configuration provides a CORESET applicable to two patterns in each pair of 300 / 302, 600 / 602, 800 / 802, 1000 / 1002, 1200 / 1202, or 1400 / 1402. Thus, when the UE 102 monitors the control channel according to one pattern or the other, the UE 102 searches for DCI according to the CORESET information during the PDCCH opportunity. However, in another implementation, the gNB 104 provides a separate CORESET for each of the two modes in a pair 300 / 302, 600 / 602, 800 / 802, 1000 / 1002, 1200 / 1202, or 1400 / 1402. In this implementation, the UE 102 searches for DCI according to a first CORESET during a PDCCH opportunity associated with the first mode and searches for DCI according to a different second CORESET during a PDCCH opportunity associated with the second mode.

[0082] As a specific example, the gNB 104 may send an RRC message including two search space configurations (e.g., two SearchSpace IEs) and two CORESET configurations (e.g., two ControlResourceSet IEs) to the UE 102. Alternatively, the gNB 104 may send a first RRC message including a first search space configuration and a corresponding CORESET, and a second RRC message including a different second search space configuration and a corresponding CORESET to the UE 102. As in the implementation described above, the gNB 104 may use the SearchSpace IE and the ControlResourceSet IE to provide the search space configuration and the CORESET. The two CORESETs provided by the gNB 104 in this implementation may be the same or different. As another example, the gNB 104 may send three RRC messages to the UE 102 as part of the configuration: a first RRC message including the first search space configuration, a second RRC message including the second search space configuration, and a third RRC message including a CORESET for use with two modes (or, two CORESETs for use with the corresponding modes).

[0083] As discussed above, the gNB 104 sends a WUS or COT indicator in some cases. The WUS or 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 RS (CSI-RS), a demodulation reference signal (DMRS) in a PDCCH, or a DMRS in a GC-PDCCH), and / or a DCI in a PDCCH. Generally, the WUS or COT indicator may depend on the implementation of the gNB 104, or the gNB 104 may be able to select different WUS or COT indicators depending on the capabilities of the UE 102 and / or the configuration of the NR-U cell 106.

[0084] In addition to using a WUS or COT indicator to notify UE 102 that COT 322, 622, 822, 1022, 1222, or 1422 has begun, gNB 104 may also send a WUS to UE 102 to cause UE 102 to begin monitoring PDCCH opportunities according to pre-COT pattern 330, 630, 830, 1030, 1230, or 1430. For example, UE 102 may not monitor any PDCCH opportunities until the first WUS is received from gNB 104. In other implementations, UE 102 may monitor PDCCH opportunities according to pre-COT pattern 330, 630, 830, 1030, 1230, or 1430 regardless of whether UE 102 has received a WUS from gNB 104.

[0085] As also discussed above, in some implementations, the gNB 104 provides a COT structure indication to the UE 102 that indicates an end time and / or duration of the COT 322, 622, 822, 1022, 1222, or 1422. For example, the COT structure indication may indicate the COT end time or duration as X (e.g., 1, 2, 3, ... N, where N is a positive integer) time units (e.g., OFDM symbols, time slots, subframes, frames) relative to some start time that the UE 102 knows a priori or can otherwise determine. As a more specific example, the start time may be a time unit during which the UE 102 receives the COT structure indication. Thus, if the UE 102 receives a COT during the Yth time unit, and the COT structure indicates a COT duration of X, then the UE 102 may determine that the COT lasts from the Yth time unit to the (X+Y)th time unit. As another example, the start time may occur n time units after UE 102 receives the COT structure indication, and both UE 102 and gNB 104 may store the same value of n. In this case, UE 102 may determine that the COT lasts from the (Y+n)th time unit to the (X+Y+n)th time unit.

[0086] Additionally, in some cases, the gNB 104 may send multiple instances of the COT structure indication and vary the content of the indication based on the remaining duration of the COT 322, 622, 822, 1022, 1222, or 1422 (e.g., as described above in conjunction with Figure 4 discussed). For example, in a first instance, the gNB 104 may send a COT structure indication according to which the COT is Y time units long. However, in a second instance occurring L time units later, the gNB 104 may send a COT structure indication according to which the remaining duration of the COT is YL time units. Similar to the above example, the values ​​of Y and L may be 1, 2, 3, or any other suitable positive integer. Also similar to the above example, the COT structure indication may reference the duration of the COT and / or the end time of the COT relative to a start time that the UE 102 is aware of (e.g., based on a 3GPP specification or an explicit indication from the gNB 104). In some implementations, the gNB 104 sends multiple instances of the COT structure indication during a monitoring opportunity of a pre-COT mode, or more specifically, during monitoring opportunities of a pre-COT mode and a COT mode that overlap with each other.

[0087] In an implementation where the gNB 104 indicates the duration (310, 510, 710, 910, 1110, or 1310) of the COT 322, 622, 822, 1022, 1222, or 1422 in a broadcast message, the broadcast message may be, for example, a system information block (SIB) or a dedicated message such as RRC Setup, RRC Resume, RRC Reestablishment, or RRCReconfiguration. In yet another implementation, each of the UE 102 and the gNB 104 stores the predefined duration of the COT in a respective local memory.

[0088] In some implementations where the UE 102 and the gNB 104 may use the GC-PDCCH, in various scenarios, the gNB 104 may send a COT structure indication on the PDCCH or the GC-PDCCH during either a PDCCH opportunity or a GC-PDCCH opportunity. As an example, the gNB 104 sends the COT structure indication on the PDCCH during a PDCCH opportunity of a pre-COT mode 330, 630, 830, 1030, 1230, or 1430. As another example, the gNB 104 sends the COT structure indication on the GC-PDCCH during a PDCCH opportunity of a pre-COT mode 330, 630, 830, 1030, 1230, or 1430. As yet another example, the gNB 104 sends a COT structure indication on the GC-PDCCH during a GC-PDCCH opportunity of a pre-COT mode 330, 630, 830, 1030, 1230, or 1430 or a GC-PDCCH opportunity of another mode.

[0089] The gNB 104 may send a DCI during a PDCCH opportunity and include the COT indication in the DCI. In other implementations, the gNB 104 sends the COT structure indication in a MAC protocol data unit (PDU). For example, the COT structure indication may be a MAC CE in a MAC PDU. As an alternative, the COT structure indication may be an RRC IE in an RRC message, and the gNB 104 includes the RRC message in the MAC PDU.

[0090] When the gNB 104 in the above example establishes COT 322, 622, 822, 1022, 1222, or 1422, the gNB 104 successfully completes a channel access procedure on the shared carrier, such as an LBT procedure. As a result, the gNB 104 obtains authorization for the channel.

[0091] When the gNB 104 uses a WUS or COT indicator to notify the UE 102 that the UE 102 should start monitoring the PDCCH according to the corresponding COT mode, the gNB 104 may notify the UE 102 of the duration of the COT 322, 622, 822, 1022, 1222, or 1422 before sending the WUS or COT indicator. To this end, the gNB 104 may use a COT structure indication. However, if the UE 102 and the gNB 104 are already aware of the predefined duration of the COT, the gNB 104 does not need to send a COT structure indication or another indicator of the duration of the COT.

[0092] In some implementations, the gNB 104 sends a WUS to the UE 102 to cause the UE 102 to begin monitoring the PDCCH according to the pre-COT mode 330, 630, 830, 1030, 1230, or 1430 during the pre-COT time 320, 620, 820, 1020, 1220, or 1420. The gNB 104 may then send a COT structure indication during one of the PDCCH opportunities of the pre-COT mode. In another implementation, the gNB 104 sends the COT structure indication during one of the PDCCH opportunities of the pre-COT mode without sending a WUS prior to sending the COT structure indication.

[0093] In various implementations or scenarios, pre-COT 320, 620, 820, 1020, 1220, or 1420 may begin immediately after UE 102 receives an indication of the first mode and the second mode (204, 504, 704, 904, 1104, or 1304), or at some point after UE 102 receives the indication. In addition, gNB 104 may provide indications of the first mode and the second mode at different times and in different configuration messages.

[0094] As described above, at the instant that gNB 104 establishes the COT, the pre-COT ends and the COT 322, 622, 822, 1022, 1222, or 1422 begins. However, more generally, the COT start time 324, 624, 824, 1024, 1224, and 1424 need not correspond exactly to the start of the COT. For example, for the purpose of UE 102 changing its monitoring mode, the COT start time may be the time at which UE 102 receives an indication (210, 510, 710, 910, 1110, or 1310) that gNB 104 has established the COT, or another suitable time.

[0095] In some implementations, the schedule 304, 604, 804, 1004, 1204, or 1404 includes at least one control channel opportunity that is not part of the corresponding pattern pair 300 / 302, 600 / 602, 800 / 802, 1000 / 1002, 1200 / 1202, or 1400 / 1402. In some embodiments where the gNB 104 sends a WUS to the UE 102 to indicate the start of a COT, for example, the UE 102 monitors the control channel immediately (or almost immediately) after receiving the WUS, even if that time does not correspond to a control channel opportunity of any of the patterns in the pair. Thus, for example, the UE 102 may monitor the PDCCH or GC-PDCCH for a duration that begins at (or very close to) time 324, 624, 824, 1024, 1224, or 1424. This "additional" monitoring opportunity may have the same duration as the other opportunities of the pattern pair, or may have a different duration.

[0096] Consider now some example methods that may be implemented in a device operating in the wireless communication network 100 or another suitable network. These methods may be implemented in processing hardware, for example, as software instructions executable on one or more processors.

[0097] Fig.15 An example method 1500 for monitoring a control channel (eg, a PDCCH or a GC-PDCCH) is shown. The method 1500 is implemented, for example, in a user equipment such as the UE 102 (eg, by the control channel monitoring module 122).

[0098] At block 1502, a user equipment monitors a control channel on a shared carrier according to a pre-transmission pattern of control channel opportunities (eg, Figure 2 Monitoring in 206, Figure 5 Monitoring in 506, Figure 7 Monitoring in 706, Fig. 9 Monitoring in 906, monitoring Fig.11 1106 in, or Fig.13 Monitoring 1306 in). The pre-transmission may be, for example, Figure 3 Mode 330, Figure 6 Mode 630, Figure 8 Mode 830, Fig.10 Mode 1030, Fig.12 Mode 1230, or Fig.14 Mode 1430.

[0099] At block 1504, while monitoring the control channel according to the pre-transmission pattern of the control channel opportunity, the user equipment receives a signal indicating a transmission time (e.g., COT) during which the gNB 104 has accessed a shared carrier (e.g., Figure 2 Instructions in 210, Figure 5 Instructions in 510, Figure 7 Instructions 710, Fig. 9 Instructions in 910, Fig.11 Instructions 1110, or Fig.13 gNB 104 may have sought access to a shared carrier (e.g., using an LBT procedure) in order to send information (such as DCI and / or other control data) to UE 102.

[0100] At block 1506, the user equipment transmits a control channel opportunity according to a transmission mode (e.g., Figure 3 COT mode 332, Figure 6 COT mode 632, Figure 8 COT mode 832, Fig.10 COT mode 1032, Fig.12 COT mode 1232, or Fig.14 COT mode 1432 in the shared carrier) monitors the control channel (e.g., Figure 2 Monitoring in 212, Figure 5 Monitoring in 512, Figure 7 Monitoring in 712, Fig.11 Monitoring 1112, or Fig.13 Monitoring 1312 in the transmission mode). At least one control channel opportunity of the transmission mode overlaps with the control channel opportunity of the pre-transmission mode.

[0101] Fig.16 An example method 1600 for configuring a user equipment to monitor a control channel (e.g., a PDCCH or a GC-PDCCH) is shown. The method 1600 is implemented, for example, in a base station such as gNB 104 (e.g., via components 132-136).

[0102] At block 1602, the base station determines that a shared carrier is available to the base station at a certain transmission time. Block 1602 may include, for example, performing a successful LBT procedure to establish a COT (e.g., Figure 2 Establishment 208 Figure 5 Establishment 508, Figure 7 The establishment of 708, Fig. 9 The establishment of 908, Fig.11 1108, or Fig.13 Establishment 1308 in).

[0103] At block 1604, the base station sends a signal to the user equipment indicating a transmission time during which the shared carrier is available to the base station. The signal causes the user equipment to monitor the control channel on the shared carrier according to a pre-transmission pattern of the control channel opportunity before the transmission time (e.g., according to Figure 3 Mode 330, Figure 6 Mode 630, Figure 8 Mode 830, Fig.10 Mode 1030, Fig.12 Mode 1230, or Fig.14 The mode 1430 is carried out Figure 2 Monitoring in 206, Figure 5 Monitoring in 506, Figure 7 Monitoring in 706, Fig. 9 Monitoring in 906, Fig.11 Monitoring 1106, or Fig.13 1306) switches to monitoring the control channel on the shared carrier according to the transmission mode of the control channel opportunity during the transmission time (for example, according to Figure 3 COT model 332, Figure 6 COT mode 632, Figure 8 COT mode 832, Fig.10 COT mode 1032, Fig.12 COT mode 1232, or Fig.14 The COT model 1432 is carried out Figure 2 Monitoring in 212, Figure 5 Monitoring in 512, Figure 7 Monitoring in 712, Fig. 9 Monitoring in 912, Fig.11 Monitoring 1112, or Fig.13 1312 in monitoring). The transmission mode is different from the pre-transmission mode, but includes at least one control channel opportunity overlapping with the control channel opportunity of the pre-transmission mode.

[0104] The following additional considerations apply to the foregoing discussion.

[0105] The user equipment (e.g., UE 102) in which the technology of the present disclosure can be implemented can be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point of sale (POS) terminal, a health monitoring device, a drone, a camera, a streaming media protection lock or another personal media device, a wearable device (such as a smart watch), a wireless hotspot, a femtocell or a broadband router. In addition, in some cases, the user equipment can be embedded in an electronic system, such as a head unit or an advanced driver assistance system (ADAS) of a vehicle. Further, the user equipment can be operated as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user equipment may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0106] Certain implementations are described in this disclosure as including logic or several components or modules. A module can be a software module (e.g., code stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit that is capable of performing certain operations and can be configured or arranged in a certain manner. A hardware module can include dedicated circuits or logic that are permanently configured (e.g., as a dedicated processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform certain operations. A hardware module can also include programmable logic or circuits (e.g., contained within a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The decision to implement a hardware module in a dedicated and permanently configured circuit or in a temporarily configured circuit (e.g., configured by software) can be driven by cost and time considerations.

[0107] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors.

[0108] After reading this disclosure, those skilled in the art will understand additional alternative structures and functional designs for scheduling control channel information through the principles disclosed herein. Therefore, although specific implementations and applications have been shown and described, it should be understood that the disclosed implementations are not limited to the precise constructions and components disclosed herein. Various modifications, changes and variations that will be apparent to those of ordinary skill in the art may be made in the arrangement, operation and details of the methods and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.

Claims

1. A method in a user equipment of obtaining control channel information from a base station communicating with the user equipment via a carrier in an unlicensed or otherwise shared spectrum, the method comprising: monitoring a control channel on the carrier according to a pre-transmission pattern of control channel opportunities; receiving, when monitoring the control channel according to the pre-transmission pattern, downlink control information DCI from the base station via the carrier, the DCI indicating that the user equipment is to start monitoring according to a transmission pattern of control channel opportunities, the transmission pattern of the control channel opportunities being different from the pre-transmission pattern but including at least one control channel opportunity overlapping with the control channel opportunity of the pre-transmission pattern and including more or less control channel opportunities per unit time than the pre-transmission pattern; as well as In response to receiving the DCI, the control channel on the carrier is monitored according to the transmission pattern during a transmission time when the carrier is available to the base station.

2. The method according to claim 1, further comprising: receiving, from the base station via the carrier, one or more messages collectively indicating a first pattern of control channel opportunities and a second pattern of control channel opportunities, wherein the pre-transmission pattern is a first combination of control channel opportunities from one or both of (i) the first pattern and (ii) the second pattern, wherein the transmission pattern is a second combination of control channel opportunities from one or both of (i) the first pattern and (ii) the second pattern, and The second combination is different from the first combination.

3. The method according to claim 2, wherein: Monitoring the control channel according to the pre-transmission pattern includes monitoring the control channel during all control channel opportunities of the first pattern and all control channel opportunities of the second pattern.

4. The method according to claim 3, wherein: Monitoring the control channel according to the transmission mode includes monitoring the control channel during all control channel opportunities of the first mode and not during control channel opportunities of the second mode.

5. The method according to claim 3, wherein: Monitoring the control channel according to the transmission mode includes monitoring the control channel only during control channel opportunities of the first mode that overlap with control channel opportunities of the second mode.

6. The method according to claim 2, wherein: Monitoring the control channel according to the pre-transmission pattern includes monitoring the control channel during all control channel opportunities of the first pattern.

7. The method according to claim 6, wherein: Monitoring the control channel according to the transmission mode includes monitoring the control channel during all control channel opportunities of the first mode and all control channel opportunities of the second mode.

8. The method according to claim 6, wherein: Monitoring the control channel according to the transmission mode includes monitoring the control channel only during control channel opportunities of the first mode that overlap with control channel opportunities of the second mode.

9. The method according to claim 2, wherein: Receiving the one or more messages collectively indicating the first mode and the second mode comprises receiving: one or more radio resource control, RRC, messages; One or more DCIs; or One or more messages including a Medium Access Control (MAC) control element.

10. The method according to claim 2, wherein: Receiving the one or more messages collectively indicating the first mode and the second mode comprises receiving an indication of a first time-frequency resource and an indication of a second time-frequency resource; Monitoring the control channel during control channel opportunities of the first pattern comprises monitoring the control channel using the first time-frequency resources; as well as Monitoring the control channel during control channel opportunities of the second pattern includes monitoring the control channel using the second time-frequency resources.

11. The method according to claim 1, further comprising: After receiving the DCI and before monitoring the control channel according to the transmission mode, monitoring the control channel on the carrier according to the pre-transmission mode during the transmission time for (i) a predetermined number of control channel opportunities or (ii) a number of control channel opportunities indicated in a message received by the user equipment from the base station.

12. The method according to claim 1, further comprising: Prior to receiving the DCI, a signal is received from the base station via the carrier, the signal causing the user equipment to enter a mode in which the user equipment can decode the control channel information.

13. The method according to claim 1, wherein: The DCI also indicates one or more of (i) the transmission time has started, (ii) the duration of the transmission time, or (iii) the end of the transmission time.

14. The method according to claim 1, wherein: The received DCI is a retransmission of an earlier DCI, and wherein the DCI indicates a remaining duration of the transmission time.

15. A user equipment comprising processing hardware and configured to perform the method according to any one of claims 1 to 14.

16. A method in a base station for providing control channel information to a user equipment communicating with the base station via a carrier in an unlicensed or otherwise shared spectrum, the method comprising: determining, using a channel access procedure, that the carrier is available to the base station within a transmission time; as well as Downlink control information DCI is sent to the user equipment, indicating that the user equipment is to start monitoring according to a transmission mode of a control channel opportunity, the DCI causing the user equipment to switch from (i) monitoring the control channel on the carrier according to a pre-transmission mode of a control channel opportunity before the transmission time to (ii) monitoring the control channel on the carrier according to the transmission mode during the transmission time, and the transmission mode is different from the pre-transmission mode but includes at least one control channel opportunity overlapping with the control channel opportunity of the pre-transmission mode and includes more or less control channel opportunities per unit time than the pre-transmission mode.

17. The method according to claim 16, further comprising: At least a portion of the control channel information is sent to the user equipment via the carrier during at least one control channel opportunity in the transmission mode.

18. The method according to claim 16 or 17, wherein: The DCI indicates one or more of (i) the transmission time has started, (ii) the duration of the transmission time, or (iii) the end of the transmission time.

19. The method according to claim 16, wherein: The DCI is a first DCI indicating the transmission time, and the method further includes: A second DCI indicating a remaining duration of the transmission time is sent to the user equipment.

20. The method of claim 16, further comprising: sending one or more messages to the user equipment that collectively indicate a first pattern of control channel opportunities and a second pattern of control channel opportunities, The pre-transmission pattern is a first combination of control channel opportunities from one or both of (i) the first mode and (ii) the second mode, and the transmission pattern is a second combination of control channel opportunities from one or both of (i) the first mode and (ii) the second mode, and the second combination is different from the first combination.

21. The method according to claim 20, wherein: The pre-transmission pattern includes all control channel opportunities of the first pattern and all control channel opportunities of the second pattern.

22. The method according to claim 21, wherein: The transmission pattern includes all control channel opportunities of the first pattern and does not include control channel opportunities of the second pattern.

23. The method according to claim 21, wherein: The transmission pattern includes only control channel opportunities of the first pattern that overlap with control channel opportunities of the second pattern.

24. The method according to claim 20, wherein: The pre-transmission pattern includes all control channel opportunities of the first pattern.

25. The method according to claim 24, wherein: The transmission pattern includes all control channel opportunities of the first pattern and all control channel opportunities of the second pattern.

26. The method of claim 24, wherein: The transmission pattern includes only control channel opportunities of the first pattern that overlap with control channel opportunities of the second pattern.

27. The method of claim 20, wherein: Sending the one or more messages to the user equipment includes sending an indication of a first time-frequency resource and an indication of a second time-frequency resource to the user equipment; Monitoring the control channel during the control channel opportunities of the first mode causes the user equipment to monitor the control channel using the first time-frequency resources; as well as Monitoring the control channel during control channel opportunities of the second pattern causes the user equipment to monitor the control channel using the second time-frequency resources.

28. The method of claim 20, wherein: Sending the one or more messages to the user equipment includes: sending one or more radio resource control (RRC) messages to the user equipment; Sending one or more DCIs to the user equipment; or One or more messages including a medium access control (MAC) control element are sent to the user equipment.

29. A base station comprising processing hardware and configured to perform the method according to any one of claims 16 to 28.

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