Optimization of Wake-up Signal Monitoring

Abstract

Methods and devices for adapting wake-up signal monitoring to optimize power saving performance are described. In one embodiment, a UE can be configured to selectively skip WUS monitoring based on the current UE context. In another embodiment, WUS / PDCCH monitoring and / or other UE procedures can be adapted based on statistics related to the wake-up signal transmitted from the base station to the UE.

Description

Technical Field

[0001] The present disclosure generally relates to discontinuous reception (DRX) of wireless devices in a wireless communication network, and more particularly, to wake-up signal monitoring in combination with DRX to further reduce the power consumption of wireless devices. Background Art

[0002] One of the power consumption activities of a user equipment (UE) in radio resource control (RRC)_CONNECTED mode is to monitor the physical downlink control channel (PDCCH). In this mode, the UE needs to perform blind detection in its configured control resource set (CORESET) to identify whether downlink control information (DCI) is sent to the UE on the PDCCH. On the other hand, in most PDCCH monitoring occasions, the UE is not scheduled, and thus, the UE monitoring is a waste of energy in almost all cases.

[0003] In Release 15, discontinuous reception (DRX) is used to reduce power consumption. In DRX mode, after the UE successfully decodes the scheduled PDCCH, the UE will start an inactivity timer. Once the inactivity timer expires, the UE will enter sleep following a certain sleep and OnDuration (so-called DRX cycle) pattern. Using this DRX technology, the network will only transmit the DCI scheduling the UE for downlink transmission during the OnDuration of the DRX cycle. Therefore, the UE only needs to monitor the PDCCH during those OnDurations and can sleep between the OnDurations in consecutive DRX cycles to save energy. Although DRX reduces power consumption, DRX still requires the UE to wake up quite frequently, especially when the DRX cycle length is relatively short. In addition, when the OnDuration is relatively long relative to the duration of the DRX cycle, the UE will waste a large amount of energy.

[0004] Given the drawbacks of DRX, techniques that can reduce unnecessary PDCCH monitoring opportunities during the OnDuration of a DRX cycle will help further reduce power consumption. The introduction of the Wake-up Signal (WUS) can be considered one of the efficient solutions to improve the power consumption of the UE. When WUS is adopted, if the network wishes to send DCI scheduling a downlink transmission to the UE, the network will send the WUS to the UE before the start of the next OnDuration of the DRX cycle. When WUS is implemented, the default behavior of the UE is to wake up and monitor the PDCCH only within the next OnDuration of the DRX cycle when the WUS is detected. If the WUS is not detected, the UE remains in the sleep mode during the next OnDuration. When there is data in the buffer to be transmitted to the UE, the network will send the WUS itself. By allowing the UE to perform PDCCH monitoring only when there will be a transmission on the Physical Downlink Shared Channel (PDSCH), the UE energy consumption can be significantly reduced. In addition, compared with normal PDCCH monitoring, WUS monitoring can be set to be more power-efficient and thus further improve the UE energy efficiency.

[0005] One of the drawbacks of using WUS is due to the fact that even when the network sends the WUS to wake up the UE within the next OnDuration, the UE may not always successfully detect / decode the WUS during the WUS monitoring opportunity. In this case, the UE remains in the sleep state and will miss the scheduled PDCCH from the network during the OnDuration. In this case, the UE will not receive the scheduled data transmission on the PDSCH. The "missed" WUS will increase the latency and reduce the throughput. Even worse, when the UE misses the PDSCH transmission from the network within several opportunities and fails to provide the expected acknowledgement (ACK) or negative acknowledgement (NACK) feedback, a Radio Link Failure (RLF) may be declared, resulting in service loss and interruption. In this case, the UE needs to re-establish the connection, which requires a large amount of power. Therefore, due to the "missed" WUS detection, the potential power savings may be significantly diluted.

[0006] Another potential drawback of the WUS solution is that when data is transmitted from the network to the UE, the UE needs to wake up twice, i.e., once to monitor the WUS monitoring occasion and the second time during the next OnDuration of the DRX cycle. When WUS is not implemented, the UE only needs to wake up once, i.e., during the OnDuration of the DRX cycle. When there is frequent data transmission from the network to the UE, the power saving gain from using WUS may be significantly reduced and, in some cases, the power consumption may increase. Additionally, during the gap between the WUS monitoring occasion and the OnDuration, the UE may not be able to return to deep sleep. The UE may need to stay awake or return to a lighter sleep state, which consumes more power than deep sleep. Summary of the Invention

[0007] The present disclosure provides methods and apparatuses for WUS monitoring and PDDCH monitoring and for adapting UE procedures based on WUS transmitted by a base station. In one embodiment, the UE can be configured to selectively skip WUS monitoring based on the current UE context. In another embodiment, the WUS / PDCCH monitoring and / or other UE procedures can be adapted based on statistics related to the WUS transmitted from the base station to the UE.

[0008] The methods and apparatuses described herein can achieve more efficient UE power consumption and avoid PDCCH reception quality degradation, especially when the WUS reliability is rather limited. Additionally, the present disclosure presents techniques for using WUS statistics to assist the UE such that the UE can actively perform efficient procedures related to WUS monitoring and efficient responses to WUS commands and thereby optimize UE power consumption and reduce network costs caused by unsuccessful WUS detections.

[0009] A first aspect of the present disclosure includes a method of WUS monitoring implemented by a UE. In one embodiment, the method includes selectively monitoring a WUS monitoring occasion before the OnDuration of a DRX cycle for the WUS depending on a predetermined criterion. The method further includes: when monitoring of the WUS monitoring occasion is skipped, waking up and monitoring a downlink control channel during the corresponding OnDuration of the DRX cycle.

[0010] The second aspect of the present disclosure includes a UE configured to execute the method according to the first aspect. In one embodiment, the UE includes an interface circuit for communicating with a base station and a processing circuitry. The processing circuitry is configured to selectively monitor a WUS monitoring occasion before the OnDuration of a DRX cycle for WUS depending on a predetermined criterion. The processing circuitry is configured to wake up and monitor a downlink control channel during the corresponding OnDuration of the DRX cycle when skipping the monitoring of the WUS monitoring occasion.

[0011] The third aspect of the present disclosure includes a method for adapting UE procedures based on a WUS transmitted by a base station. In one embodiment, the method includes determining statistical characteristics of the WUS transmitted by the base station. The method further includes preemptively adapting UE procedures based on the statistical characteristics of the WUS transmitted by the base station.

[0012] The fourth aspect of the present disclosure includes a UE configured to execute the method according to the third aspect. In one embodiment, the UE includes an interface circuit for communicating with a base station and a processing circuitry. The processing circuitry is configured to determine statistical characteristics of the WUS transmitted by the base station. The processing circuitry is configured to preemptively adapt UE procedures based on the statistical characteristics of the WUS transmitted by the base station.

[0013] The fifth aspect of the present disclosure includes a computer program product that includes executable instructions that, when executed by a processing circuitry in a UE, cause the UE to execute the method according to the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A wireless communication network configured to implement the WUS monitoring described herein is shown.

[0015] Figure 2 Time-frequency resources for communication in a wireless communication network are shown.

[0016] Figure 3 An exemplary DRX cycle with a WUS monitoring occasion is shown.

[0017] Figure 4 An exemplary method of selective WUS monitoring is shown.

[0018] Figure 5 An exemplary method of adapting UE procedures based on a WUS transmitted by a base station is shown.

[0019] Figure 6 An exemplary UE configured to perform selective WUS monitoring is shown.

[0020] Figure 7An exemplary UE configured to adapt UE procedures based on a WUS transmitted by a base station is shown.

[0021] Figure 8 An exemplary UE configured to perform selective WUS monitoring and adapt UE procedures based on a WUS transmitted by a base station is shown. DETAILED DESCRIPTION

[0022] Referring now to the drawings, exemplary embodiments of the present disclosure will be described in the context of fifth generation (5G) and next generation radio (NR) communication networks. Those skilled in the art can readily adapt the power saving techniques described herein for communication networks based on other radio access technologies (RATs), such as Long Term Evolution (LTE) networks, Wideband Code Division Multiple Access (WCDMA) networks, Code Division Multiple Access (CDMA) 2000 networks, Wireless Fidelity (WiFi) networks, Worldwide Interoperability for Microwave Access (WiMAX) networks, Wireless Local Area Network (LAN) (WLAN), Narrowband Internet of Things (NB-IoT) networks, or other wireless communication networks.

[0023] Figure 1 A wireless communication network 10 including a base station 200 is shown, the base station 200 providing service to user equipment (UE) 100 in a cell 20 served by the base station 200. In applicable standards, the base station 200 is sometimes referred to as an evolved Node B (eNB) or a 5G Node B (gNB). The UE 100 (also referred to as a wireless device or wireless terminal) may include a cellular phone, a smart phone, a laptop computer, a notebook computer, a tablet computer, a machine-to-machine (M2M) communication device (also referred to as a machine type communication (MTC) device), or other devices having wireless communication capabilities. Although only a single cell 20 is shown, those skilled in the art will appreciate that a typical wireless communication network 10 may include many cells 20.

[0024] Radio resources in NR can be considered as a time-frequency grid 50 as shown Figure 2 In the time domain, physical resources are divided into subframes. Each subframe includes a number of symbols. For a normal cyclic prefix (CP) length, suitable for cases where multipath dispersion is not expected to be extremely severe, a subframe includes fourteen symbols. If an extended CP is used, a subframe includes twelve symbols. In the frequency domain, physical resources are divided into subcarriers. The number of subcarriers varies according to the allocated system bandwidth. A subframe typically includes two time slots, which can be further subdivided into mini-slots. A mini-slot includes one or more symbol periods within a time slot. The smallest element of the time-frequency grid 50 is a resource element (RE) 52, which includes the intersection of one subcarrier and one symbol.

[0025] The 3rd Generation Partnership Project (3GPP) is defining the technical specifications of the New Radio (NR) (e.g., 5G). In Release 15 (Rel-15) NR, the UE 100 can be configured with up to four carrier Bandwidth Parts (BWPs) in the downlink (DL), where a single DL carrier BWP is active at a given time. The UE 100 can be configured with up to four carrier BWPs in the uplink (UL), where a single UL carrier BWP is active at a given time. If the UE 100 is configured with supplementary UL, the UE 100 can additionally be configured with up to four carrier BWPs in the supplementary UL, where a single supplementary UL carrier BWP is active at a given time.

[0026] For a carrier BWP with a given parameter set a contiguous set of physical resource blocks (PRBs) is defined and numbered from 0 to where i is the index of the carrier BWP. A resource block (RB) is defined as 12 consecutive subcarriers in the frequency domain.

[0027] As given in Table 1 below, multiple Orthogonal Frequency Division Multiplexing (OFDM) parameter sets are supported in NR where the subcarrier spacing and cyclic prefix of a carrier bandwidth part are configured by different higher layer parameters for DL and UL respectively.

[0028] Table 1: Supported transmission parameter sets.

[0029] #timg# #timg# Cyclic Prefix 0 15 Normal 1 30 Normal 2 60 Normal, Extended 3 120 Normal 4 240 Normal

[0030] The base station 200 transmits information to the UE 100 on the physical DL channel. The physical DL channel corresponds to a set of resource elements (REs) carrying information originating from higher layers. The currently defined physical DL channels include the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH), and the Physical Broadcast Channel (PBCH). The PDSCH is the main physical channel for unicast DL data transmission, but is also used for the transmission of Random Access Response (RAR), certain System Information Blocks (SIBs), and paging information. The PDCCH is used to transmit the downlink control information (DCI) required to receive the PDSCH (mainly scheduling decisions), and for UL scheduling grants (SGs) that enable transmission on the Physical Uplink Shared Channel (PUSCH). The PBCH carries the essential system information (SI) required for the UE 100 to access the network 10.

[0031] The base station 200 is responsible for scheduling DL transmissions to the UE 100 on the PDSCH and for allocating resources for the DL transmissions. The base station 200 sends downlink control information (DCI) to the UE 100 on the PDCCH to schedule the DL transmissions of the UE 100. The DCI includes scheduling information such as the allocated resources for the DL transmission and the modulation and coding scheme (MCS).

[0032] The UE 100 transmits information to the base station 200 on the physical UL channel. The physical UL channel corresponds to a set of REs carrying information from a higher layer. The currently defined physical UL channels include the physical uplink shared channel (PUSCH), the physical uplink control channel (PUCCH), and the physical random access channel (PRACH). The PUSCH is the UL counterpart of the PDSCH. The UE 100 uses the PUCCH to transmit UL control information (UCI), which includes hybrid automatic repeat request (HARQ) acknowledgments, channel state information (CSI) reports, etc. The PRACH is used for random access preamble transmission.

[0033] The base station 200 is responsible for scheduling UL transmissions from the UE 100 and for allocating resources for the UL transmissions. After scheduling the UL transmissions and allocating resources, the base station 200 sends a scheduling grant (SG) to the UE 100, which indicates the resources on which the UE 100 has been scheduled and the transmission format for the scheduled transmission. The UL grant is sent to the UE 100 on the PDCCH. After receiving the UL grant, the UE 100 determines the UL transmission power for the transmission and transmits data to the base station 200 on the PUSCH resources indicated in the SG.

[0034] Discontinuous reception (DRX) is a technique for saving power in the UE 100. When DL transmissions from the base station 200 are not required, DRX allows the UE 100 to transition to a lower power state or "sleep mode" and wake up periodically to monitor paging messages and scheduling information.

[0035] Figure 3The DRX operation is shown in a simplified form. A DRX cycle is defined by a DRX period and an OnDuration, during which the UE 100 wakes up and monitors the PDCCH to obtain the DCI addressed to the UE 100. If the UE 100 detects the DCI addressed to the UE 100, the UE 100 starts an Inactivity Timer (IAT) and continues to monitor the PDCCH until the Inactivity Timer expires. The Inactivity Timer determines the number of consecutive PDCCH subframes or time slots during which the UE 100 will stay awake after the subframe or time slot in which the PDCCH indicates the initial UL, DL, or sidelink (SL) data transmission for the UE 100. If the UE 100 receives the DCI addressed to the UE 100, it extends or resets the Inactivity Timer and continues to monitor the PDCCH. When the Inactivity Timer expires, the UE 100 has the opportunity to sleep until the next OnDuration starts. In one embodiment, when the Inactivity Timer expires, the UE 100 stops receiving transmissions from the base station 200 (e.g., no control monitoring) and enters sleep until the next DRX cycle starts. The OnDuration and the duration during which the Inactivity Timer is running are generally referred to as the active time.

[0036] DRX functionality is typically configured by Radio Resource Control (RRC), which operates on a slower timescale than the Media Access Control (MAC) layer or the Physical layer. Thus, DRX parameter settings cannot be changed quickly by RRC.

[0037] Although DRX reduces the power consumption of the UE 100, the UE 100 still needs to wake up quite frequently, especially when the DRX cycle length is relatively short. In addition, when the OnDuration is relatively long compared to the duration of the DRX cycle, the UE 100 may waste a large amount of power.

[0038] When the downlink transmission to the UE 100 is not frequent, in order to further reduce the power consumption, the network may send a WUS to the UE 1000 before the start of the OnDuration, as Figure 3 shown. The UE 100 may be configured to wake up during the WUS monitoring occasion to monitor the WUS. If the WUS is detected, the UE 100 wakes up in the next OnDuration of the DRX cycle to monitor the PDCCH. The UE 100 may enter a micro-sleep state during the gap between the WUS monitoring occasion and the start of the next OnDuration, or may stay awake. If the WUS is not detected during the WUS monitoring occasion, the UE 100 returns to the sleep mode and sleeps through the next OnDuration of the DRX cycle.

[0039] Generally, from a power consumption perspective, it is beneficial to use WUS. However, in scenarios where it is desired that the UE 100 receive frequent downlink transmissions, using WUS may increase power consumption. In such cases, the UE 100 needs to wake up twice; once to monitor WUS and once to monitor the PDCCH. Waking up to monitor WUS consumes some power. In addition, the UE 100 may not be able to return to the deep sleep state between the WUS monitoring occasion and the next OnDuration of the DRX cycle. Instead, the UE 100 may stay awake or return to a lighter sleep state (e.g., micro-sleep mode), which consumes more power than the deep sleep state. The additional power consumption depends on the WUS configuration (e.g., aggregation level (AL), bandwidth (BW), transmission power), DRX configuration (e.g., DRX offset, DRX cycle, DRX OnDuration), WUS offset, the number of WUS monitoring occasions in each DRX cycle, and the position of other UE measurement occasions (e.g., synchronization signaling block (SSB)) relative to WUS and DRX OnDuration.

[0040] In addition, even when the network adapts the WUS transmission to a robust configuration (e.g., by a higher aggregation level (AL), higher power, using multiple WUS occasions / transmissions, etc.), problems may occur when the UE 100 is not able to reliably receive the WUS. For example, a "missed" WUS may occur when the UE 100 is mobile and the WUS adaptation is based on "old" channel information. A "missed" WUS may also occur when using the grand format of WUS (e.g., high payload in WUS, etc.). In a group WUS scenario, the network may decide to send the WUS using resources that are considered robust only for the majority of the UEs 100 in the group to save network resources. Some users in the same group may have poor channel conditions (relative to other UEs in the group). For the UE 100 with poor channel conditions, the WUS configuration may be insufficient. When the UE 100 misses the WUS, the UE 100 may also miss multiple PDCCH / PDSCH transmissions, which may trigger the declaration of RLF. Then, the UE 100 needs to reconnect to the network, which has associated latency and additional energy consumption for the UE 100. The cost of missing the WUS can be quite high.

[0041] One aspect of the present disclosure is an adaptive mechanism that enables the UE 100 to identify scenarios or conditions where the likelihood and cost of WUS reception where the benefits from using WUS may be limited and / or unsuccessful may be high. If the cost / benefit trade-off is unfavorable to the UE 100, the UE 100 may omit WUS monitoring (i.e., intentionally ignore available WUS signals) and directly wake up within the OnDuration at least temporarily.

[0042] Some scenarios may be based on the performance impact of WUS handling attributable to the data traffic pattern. For example, when the UE 100 is expecting data traffic within the OnDuration of an upcoming DRX cycle, WUS monitoring may be useless. Data traffic may be expected based on the traffic pattern associated with the application, past traffic patterns, or scheduled downloads.

[0043] Some scenarios may be based on the performance impact of WUS handling attributable to the reception condition. Some such example scenarios detectable by the UE include high vehicle speed, frequent RLF when WUS is configured, frequent reception of WUS-like signals that are not successfully decoded, etc.

[0044] In addition, some scenarios may be based on the UE power consumption associated with WUS handling attributable to the UE configuration. Such example scenarios include improper configuration of the DRX cycle compared to the traffic, WUS offset or MCS, DRX offset and measurement location, improper configuration of non-power-constrained configurations, etc.

[0045] Some scenarios may be based on the performance impact of WUS handling attributable to the reception condition. Some such example scenarios detectable by the UE include high vehicle speed, frequent RLF when WUS is configured, frequent reception of WUS-like signals that are not successfully decoded, etc.

[0046] Typically, when in the RRC_Connected state, the UE 100 is configured for DRX. In addition, WUS monitoring is configured for the UE 100. More specifically, the UE 100 is configured with one or more WUS monitoring occasions in X time slots before the OnDuration. If the UE 100 does not detect / decoder the WUS during the WUS monitoring occasion, the default option for the UE 100 is to skip monitoring the PDCCH search space (SS) within the next DRX OnDuration. In embodiments of the present disclosure, criteria for adapting WUS monitoring are defined. These criteria may be related to, for example, expected data traffic, UE configuration, reception conditions, or any combination thereof. The UE 100 determines whether any of the criteria are met, and if so, adapts WUS reception and PDCCH monitoring based on the satisfaction of the criteria. As an example, the UE 100 may skip WUS monitoring at the next WUS monitoring occasion and wake up to monitor the PDCCH within the next OnDuration of the DRX cycle. As another example, the UE 100 may ignore negative detection results and wake up to monitor the PDCCH within the next OnDuration of the DRX cycle, thus avoiding problems that may occur in the case of a "missed" WUS.

[0047] Some scenarios in which the UE 100 may modify WUS monitoring and PDCCH monitoring are described below.

[0048] Adaptation Based on Expected Traffic

[0049] In mobile communications, the UE 100 is aware of the currently running applications, and thus, the UE 100 has knowledge of the history of past traffic and can statistically anticipate upcoming traffic. If, based on this knowledge, the UE 100 determines that it expects to receive data in the next OnDuration, the UE 100 may deliberately skip WUS monitoring in that particular WUS monitoring occasion.

[0050] For example, in one such embodiment, the UE 100 may observe that video stream buffer fill bursts arrive at certain regular intervals, which may be in a low-load network with a regular streaming bit rate. The UE 100 may skip WUS monitoring and directly wake up to monitor the PDCCH within the OnDuration in which the next buffer fill burst is expected.

[0051] In another example, the UE 100 may expect the arrival of uplink (UL) data, skip WUS monitoring, and send a scheduling request (SR) to the base station. If SR transmission is not allowed, the UE 100 may initiate a random access procedure.

[0052] In another embodiment, the UE 100 utilizes its knowledge of the desired content to estimate the desired traffic. For example, if the UE 100 expects to download a movie, it may skip the WUS and wake up within the OnDuration because it expects a more regular data stream. As another example, if the UE 100 knows that no expected content will be downloaded within the existing OnDuration, it may decide to skip the next WUS monitoring occasion and monitor the PDCCH within the next OnDuration.

[0053] However, in another embodiment, the UE 100 estimates the WUS traffic by itself. For example, the UE 100 employs a learning mechanism to evaluate the historical behavior of the base station 200. For example, the UE 100 may notice that the base station 200 transmits WUS with specific statistics, and thus, if the probability of the WUS arriving at the next occasion is higher than a specific threshold, it skips monitoring the WUS. Additionally, the UE 100 can also learn the base station behavior for specific traffic types, such as the WUS statistics for Internet browsing, downloading movies, interactive games, etc. Depending on the desired traffic type, the UE 100 can adapt its selective WUS monitoring strategy.

[0054] Adaptation Based on Reception Conditions

[0055] One of the reasons that the UE 100 may fail to detect / decode the WUS is that the channel quality between the network and the UE 100 is not sufficient for the UE 100 to decode the WUS. This situation may occur, for example, because the channel quality of the UE 100 is poor. Additionally, considering the current channel quality, it is possible that the network does not have enough resources to send a robust WUS configuration. Using a less robust WUS configuration is expected to result in an increase in the number of missed WUSs. In a group WUS scenario, most of the UEs 100 in a group may have much better channel conditions, and thus, the network may decide not to use the most robust configuration.

[0056] When the channel quality is poor, monitoring the WUS during the WUS monitoring occasion may not be beneficial and wastes energy. Therefore, if there is an indication that given the current WUS configuration, the recent channel quality (e.g., average channel condition, worst-case channel condition, etc.) is not sufficient to decode the WUS, then there is a high probability that the UE 100 will need to wake up within the next OnDuration to avoid a missed detection scenario. In this case, the UE 100 can deliberately skip the WUS and wake up during the OnDuration of the DRX cycle without monitoring the WUS. This indication can be obtained, for example, by the number (or ratio) of radio link failures (RLFs) given the current channel quality or the historical data of successfully detected / decoded WUS configurations.

[0057] In another embodiment, if the UE 100 notices a deterioration in channel quality in a specific TCI state and it may not be possible to reliably detect the WUS, the UE 100 may ignore monitoring the WUS in that TCI state. For example, the UE 100 may be configured with a WUS CORESET for the most recently known TCI state or several TCI states. In one method, if the primary TCI state deteriorates, the UE 100 decides to skip WUS monitoring and wake up during the OnDuration of the DRX cycle. In another example, if the channel quality is good enough for reliable WUS detection, the UE 100 may decide to still monitor the WUS in other TCI states, and the power savings achieved from skipping WUS monitoring are higher than the power consumption of WUS monitoring in multiple TCI states.

[0058] The reception condition may also be affected by UE mobility. Compared with the channel fluctuations of a stationary UE 100, the UE 100 moving at high speed experiences greater channel fluctuations. Thus, there is a possibility that the WUS configuration may be based on "old" channel information. Therefore, mobility can be used by the UE 100 as a parameter in determining whether to monitor the WUS or skip WUS monitoring and directly wake up during the OnDuration. For example, as soon as the UE 100 starts to move, or it moves at a speed greater than a predetermined threshold, the UE 100 may decide to skip WUS monitoring and wake up during the OnDuration of the DRX cycle. In an extension of this concept, several ranges of the UE 100 speed (or Doppler spread) can also be used. However, in another method, if the mobility is in the angular domain, that is, the UE 100 position is stable, but it rotates at a certain angular speed (or a combination of both), then the UE 100 skips WUS monitoring. In this case, the UE 100 may decide to skip monitoring the WUS and directly wake up because the beam quality for WUS reception cannot be ensured.

[0059] Adaptation Based on UE Configuration

[0060] UE configuration also plays an important role in determining the potential power savings gain that the UE 100 can obtain. UE configuration may include DRX configuration, WUS configuration, measurement configuration, reference signal configuration, power configuration, or other configurations that affect the power savings performance of WUS monitoring.

[0061] When the DRX and WUS features are active, it is possible that the duration of OnDuration is not significantly greater (e.g., 2 time slots) compared to the duration monitored by WUS (usually 1 time slot). For example, this can occur when WUS is also activated in short DRX or when long DRX has a relatively short cycle. In some scenarios, it is even possible that the WUS configuration includes more than one monitoring occasion, and the power consumption ratio between WUS monitoring and OnDuration increases. In this case, the power saving gain that can be obtained through WUS monitoring may decrease significantly. To optimize the power saving gain, UE 100 can deliberately skip WUS monitoring and wake up during the upcoming OnDuration. For example, UE 100 can decide to skip monitoring WUS for short DRX but monitor WUS for long DRX. In addition to using power saving as a criterion, UE 100 can also apply other criteria, such as expected traffic, mobility, etc. For example, if the expected payload is high, UE 100 can decide to completely skip WUS monitoring for short DRX.

[0062] In some scenarios, it is possible that UE 100 identifies that the DRX cycle assigned by the network is equal to or greater than the traffic periodicity expected by UE 100. In these scenarios, there is a very high probability that WUS will be sent by the network in the WUS monitoring occasion to wake up UE 100 during OnDuration. Therefore, when the DRX cycle length is greater than the periodicity of the data traffic, UE 100 can skip WUS monitoring and directly wake up during the upcoming OnDuration.

[0063] When implementing WUS, the UE 100 will monitor WUS in one or several time slots before the OnDuration. If WUS is detected, there is a high probability that the UE 100 should stay in micro-sleep (instead of light sleep or deep sleep) between the WUS monitoring occasion and the OnDuration of the DRX cycle. This situation reduces the power savings that can be obtained by implementing WUS. Setting the WUS offset large may not be beneficial because even if the UE 100 may enter a deeper sleep (e.g., light sleep), the UE 100 will experience two wake-up energy overheads (i.e., in the WUS monitoring occasion and at the start of the OnDuration). In addition, a larger WUS offset will also cause throughput loss. Since the type of sleep (i.e., micro-sleep, light sleep or deep sleep) adopted by the UE 100 depends on the length of the sleep duration, skipping the WUS monitoring may also cause the UE 100 to enter a deeper sleep state and save more energy compared to the energy saved by the WUS monitoring. Therefore, when calculating the potential power savings gain in implementing WUS monitoring, the WUS and DRX offsets can be regarded as parameters. Then, the UE 100 can decide whether it is better to monitor or skip WUS by considering these parameters. For example, if the distance between the WUS monitoring and the DRX OnDuration is higher (or lower) than a certain threshold, the UE 100 can decide to skip the WUS monitoring and directly wake up within the OnDuration.

[0064] In addition to WUS monitoring, the UE 100 may wake up to perform periodic measurements (e.g., Synchronization Signal Block (SSB) measurements). When the position of the WUS monitoring occasion is close in time to the measurement occasion, performing WUS monitoring will not result in a significant increase in energy consumption because the UE 100 will only need to wake up once. However, it is also possible that the WUS monitoring occasion and the measurement occasion are far apart, and the UE 100 will need to stay in micro-sleep state (instead of a deeper sleep state), or the UE 100 needs to wake up twice. Therefore, the WUS monitoring occasion and the measurement occasion can also be used by the UE 100 as parameters to determine whether WUS monitoring is needed. For example, if the distance between the WUS monitoring occasion and the UE 100's periodic measurement position is higher or lower than a certain threshold, the UE 100 can decide to skip the WUS monitoring and directly wake up within the OnDuration.

[0065] The power consumption of WUS monitoring depends on the WUS configuration, i.e., a more robust configuration (e.g., larger AL, BWP, CORESET, SS configuration, interleaved or non-interleaved CORESET, number of WUS monitoring occasions, etc.) consumes more power. For example, when the UE 100 has poor channel quality, the network may select a more robust configuration. In a group WUS scenario, this may also occur when the UE 100 belongs to a group of one or more UEs with poor channel quality. Since the power consumption of WUS monitoring can vary quite significantly, this power consumption can also be used by the UE 100 as a parameter to decide whether to monitor WUS in a WUS monitoring occasion.

[0066] Use of power metric

[0067] When the UE 100 fails to detect, i.e., misses, the WUS, the UE 100 may also miss multiple PDCCH / PDSCH transmissions, which may trigger the declaration of RLF. Then, the UE 100 needs to reconnect to the network, which has associated latency and additional energy consumption for the UE 100. Therefore, if RLF is declared, the UE 100 can estimate the possible additional power consumption and use this power metric as a parameter to determine whether the UE 100 should skip WUS monitoring or ignore the detection result and directly wake up within the OnDuration.

[0068] The decision on whether the UE 100 can skip WUS and directly wake up within the OnDuration can be made in different ways. For example, if one of the above parameter values / conditions is greater than / less than a certain threshold, the UE 100 can decide to skip WUS monitoring. Among other options, if a certain number of parameter values / conditions are greater than / less than certain thresholds, the UE 100 can decide to skip WUS monitoring. In yet another option, the UE 100 can check the parameter values in a sequential manner. For example, if the UE 100 mobility is higher than a certain threshold (regardless of the values of other parameters), the UE 100 can decide to skip WUS monitoring. If the UE 100 mobility is lower than this threshold, the UE 100 then checks other parameters (e.g., WUS monitoring power consumption, DRX configuration, etc.) and makes a decision accordingly. In a more advanced option, the UE 100 can use a certain weighted function to multiply each gap between the observed value and the threshold.

[0069] The decision on whether to skip WUS monitoring can be applied to the UE 100 as an entity, or it can also be implemented in a more specific way. For example, the UE 100 can decide to skip WUS monitoring in one or more specific BWPs, component carriers (CCs), etc., and not skip WUS in other BWPs or CCs.

[0070] In addition, the observed value and the threshold can be set to fixed values, or it is also possible that the threshold depends on the configuration and / or conditions of the WUS transmission (e.g., the number of receiving antennas, bandwidth, AL, WUS payload bits, mobility, etc.), or even historical data that has been updated. In addition, the observed value and the threshold can be real-valued or boolean-type values.

[0071] WUS transmissions that may not be detected

[0072] In some scenarios / embodiments, the UE 100 may experience frequent reception of WUS-like signals that are not successfully decoded. For example, the UE 100 may observe that the REs corresponding to the valid RE set according to the WUS search space are assigned a consistent power different from the power in the surrounding REs in a manner consistent with the WUS transmission, although this content is not successfully decoded as WUS DCI or other power-saving signals. The UE 100 can use the soft information of the decoder for WUS decoding. Soft information with an amplitude exceeding the threshold may indicate RE content compatible with WUS DCI, although the signal quality may not be sufficient for successful decoding. Then, the UE 100 can assume that the detected RE pattern corresponds to a WUS transmission, and upon detecting such a pattern, act as if a WUS has been detected within the associated OnDuration, and monitor the scheduled PDCCH during the time slots specified in the search space.

[0073] Unconstrained power

[0074] In some embodiments, a UE 100 unknown to the network can operate in a mode where power / energy savings are not a primary concern, e.g., connected to a charger or permanently installed with an unlimited power source. In such a scenario, when the UE 100 is aware of this operating mode, it can avoid any steps in PDCCH reception that are aimed at saving power, but may infer a performance degradation. For example, the UE 100 can omit any WUS detection and act as if a WUS has been received within the current OnDuration at each OnDuration / SS occasion. This avoids any PDCCH reception degradation caused by possible missed detections of WUS and makes the PDCCH / PDSCH reception performance statistics more robust for the UE 100 at the cost of additional energy consumption, which is immaterial in the described scenario.

[0075] Other aspects

[0076] In the case where the WUS contains information related to the configuration in which the UE 100 needs to wake up (for example, the transmission rank of multiple-input multiple-output (MIMO), the BWP, etc.), the UE 100 may wake up in the most likely configuration. In addition, it is also possible that the UE 100 wakes up with a configuration proportional to the configuration probability. For example, if in historical data, the UE 100 uses BWP1 80% and BWP2 20% in transmission, then the UE 100 can autonomously wake up within the OnDuration for 80% of the time using BWP1 and 20% of the time using BWP2, respectively.

[0077] In the case where the network sends the WUS before the OnDuration and the non-periodic CSI-RS follows, the UE 100 may also wake up during the non-periodic CSI-RS next to the OnDuration. Here, even if the UE 100 deliberately skips the WUS monitoring, the CSI report can serve as an indicator that the UE 100 will wake up within the upcoming OnDuration.

[0078] In some extensions, the UE 100 can also send an indication to the network that the UE 100 intends to deliberately skip the WUS monitoring in the above-given parameters / configurations. The UE 100 can also request the network not to implement the WUS. In these scenarios, when a similar configuration is detected, the network can configure the UE 100 not to implement the WUS.

[0079] The focus of the UE 100 skipping the WUS monitoring is that the UE 100 skips the WUS monitoring and wakes up within the next OnDuration. Alternatively, the UE 100 can (based on expected traffic, base station historical behavior, etc.) decide to skip monitoring the WUS and not wake up as long as the requirements set for the WUS detection (for example, the missed detection rate of the WUS) are met.

[0080] Figure 4Illustrates an exemplary method 300 implemented by a UE 100 that implements DRX in the RRC_Connected state. Method 300 assumes that PDCCH monitoring and WUS monitoring have been configured. Once PDCCH monitoring and WUS monitoring are configured, UE 100 selectively monitors WUS monitoring opportunities before the OnDuration of the DRX cycle depending on predetermined criteria (block 310). For example, depending on the predetermined criteria, UE 100 may wake up during some WUS monitoring opportunities to monitor WUS, but skip other WUS monitoring opportunities. The predetermined criteria may be related to the current UE context. The UE 100 context may include currently running applications or services, UE 100 configuration, the reception condition of UE 100, or some combination thereof. When skipping the monitoring of a WUS monitoring opportunity, UE 100 further wakes up and monitors the PDCCH during the corresponding OnDuration of the DRX cycle (block 320). In some embodiments, when WUS is detected during a WUS opportunity, UE 100 further monitors the PDCCH during the next OnDuration of the DRX cycle (block 330).

[0081] Some embodiments of method 300 further include remaining in the sleep mode during the next OnDuration of the DRX cycle when WUS is not detected during a WUS opportunity.

[0082] In some embodiments of method 300, the predetermined criteria are related to expected data traffic, UE 100 configuration, reception condition, or a combination thereof.

[0083] In some embodiments of method 300, selectively monitoring the WUS monitoring opportunity includes skipping the monitoring of the WUS monitoring opportunity in response to determining that expected data traffic is expected during the OnDuration of the DRX cycle. The expected data traffic may include downlink traffic or uplink traffic. As an example, UE 100 may determine the expected data traffic based on the traffic pattern of the application. As another example, UE 100 may determine the expected data traffic based on the scheduled download.

[0084] In some embodiments of method 300, selectively monitoring the WUS monitoring opportunity includes skipping the monitoring of the WUS monitoring opportunity in response to the reception condition. The reception condition may include, for example, channel quality, UE 100 mobility (e.g., speed), or transmission configuration indicator (TCI) status. In one example, when the channel quality is below a threshold, the monitoring of the WUS monitoring opportunity is skipped. In another example, when the speed of UE 100 is greater than a threshold, the monitoring of the WUS monitoring opportunity is skipped. In yet another example, depending on the TCI status, the WUS monitoring opportunity is skipped.

[0085] In some embodiments of method 300, selectively monitoring the WUS monitoring occasion includes skipping the monitoring of the WUS monitoring occasion based on UE configuration. The UE configuration may include DRX configuration, WUS configuration, measurement configuration, reference signal configuration, power configuration, or other configurations that affect the power saving performance of WUS monitoring.

[0086] In some embodiments of method 300, the WUS monitoring is skipped depending on the DRX configuration. For example, when the length of the current DRX cycle period is less than a predetermined length, UE 100 may skip the WUS monitoring and monitor the PDCCH. In another example, when the current DRX cycle period is greater than the periodicity of the desired data traffic, UE 100 may skip the WUS monitoring and monitor the PDCCH. In yet another example, when the OnDuration length of the current DRX cycle is less than a predetermined length, UE 100 may skip the WUS monitoring and monitor the PDCCH.

[0087] In some embodiments, the single wake-up monitoring is skipped depending on the WUS configuration. For example, when the offset between the WUS monitoring occasion and the start of the OnDuration of the DRX cycle is greater than a threshold, UE 100 may skip the WUS monitoring and monitor the PDCCH. As another example, UE 100 may skip the WUS monitoring and monitor the PDCCH depending on the number of WUS monitoring occasions before the OnDuration of the DRX cycle.

[0088] In some embodiments of method 300, the WUS monitoring is skipped depending on the measurement configuration. For example, when the measurement occasion occurs during the next OnDuration of the DRX cycle, or when the time period between the WUS monitoring occasion and the measurement occasion meets a threshold, UE 100 can skip the WUS monitoring and monitor the PDCCH.

[0089] In some embodiments of method 300, the WUS monitoring is skipped depending on the power configuration. For example, when UE 100 is connected to an external power source, UE 100 can skip the WUS monitoring and monitor the PDCCH.

[0090] In some embodiments of method 300, the WUS monitoring is skipped depending on the reference signal configuration. For example, in response to determining that a reference signal is expected during the next OnDuration of the DRX cycle, or when the time period between the next OnDuration of the DRX cycle and the measurement occasion meets a threshold, UE 100 can skip the WUS monitoring and monitor the PDCCH.

[0091] In some embodiments of method 300, selectively monitoring the WUS monitoring occasion includes skipping the monitoring of the WUS monitoring occasion depending on a power saving metric. The power saving metric can be calculated based on one or more of the following: the expected power consumption during the WUS monitoring occasion, the expected power saving in the case of skipping the monitoring of the PDCCH within the OnDuration, or the expected power consumption due to missing the WUS.

[0092] In some embodiments of method 300, in response to receiving an indication from the base station, the WUS monitoring is skipped and the PDCCH is monitored.

[0093] In some embodiments of method 300, UE 100 selects a reception configuration for the OnDuration depending on the historical usage of the received configuration.

[0094] According to another aspect of the present disclosure, UE 100 collects base station behavior statistics regarding WUS transmissions and adapts the WUS and PDCCH monitoring procedures accordingly to optimize power saving. Different types of statistics from previous WUS monitoring occasions are outlined below, which can be used to assist UE 100 in order to optimize power saving gains and reduce the possible additional cost of performing WUS monitoring. The statistics can take the form of a WUS reception rate (e.g., the number of WUSs actually transmitted by base station 200 in a given number of WUS monitoring by the UE), a WUS transmission pattern, and statistics related to the commands included in the WUS.

[0095] WUS reception rate

[0096] Most UE applications follow a certain traffic pattern, which can be represented by the data arrival interval time (IAT) and the packet size. Once the data arrives in the buffer of base station 200, base station 200 can send a WUS in one of the upcoming WUS monitoring occasions configured for UE 100. However, from the perspective of UE 100, the WUS monitoring occasion is closely related to the DRX cycle. In some scenarios, it is possible that the DRX cycle does not match the data IAT.

[0097] In one embodiment of the present disclosure, the WUS reception rate can be defined as the average number of WUS monitoring occasions monitored by UE 100 until UE 100 detects / decodes the WUS. In other options, the WUS reception rate can also be defined as the total number of WUSs successfully detected / decoded by UE 100 in an RRC connection divided by the total number of WUS monitoring occasions.

[0098] As a supplement to the above, the UE 100 may store the WUS reception rate based on the service type, based on the DRX type (e.g., long DRX or short DRX), etc. For example, for a video streaming service, the WUS reception rate is X, while for a video call, the WUS reception rate is Y.

[0099] In yet another option, the UE 100 can correlate the statistical behavior of the base station 200 WUS transmissions with the UE 100 uplink transmissions. For example, the UE 100 can define the WUS reception rate as the number of DRX cycles between the WUS reception and the time when the UE 100 requests data.

[0100] In one embodiment, the UE 100 can use the reception rate information to deliberately skip certain WUS monitoring opportunities and directly wake up during the OnDuration, or follow the most likely command included in the WUS. For example, assume the UE 100 is configured with a DRX cycle of 160 ms. Through WUS statistics, the UE 100 has the information that the WUS is most likely to occur after 320 ms. In this case, the UE 100 can monitor the WUS in the first WUS monitoring opportunity (i.e., the WUS monitoring opportunity of the first DRX cycle), and if there is no data, return to sleep. In the second WUS monitoring opportunity (i.e., the WUS monitoring opportunity of the second DRX cycle), the UE 100 actually expects the WUS to be transmitted based on the WUS statistics. Therefore, the UE 100 can skip the WUS monitoring opportunity and wake up within the OnDuration of the DRX cycle, or follow other most likely WUS commands.

[0101] The opposite of the above scenario is also possible, i.e., if the UE 100 does not expect the WUS in the upcoming WUS monitoring opportunity due to the previous base station 200 WUS transmission pattern, the UE 100 uses this WUS statistic to skip the WUS monitoring opportunity and stay asleep. If the base station 200 transmission pattern (at least regarding the omitted monitoring opportunities) is highly consistent, this option can be preferably used. Using this method, the UE 100 can also consider the acceptable WUS detection rate set by the standard (i.e., the ratio of the number of WUSs successfully detected by the UE 100 to the number of WUSs transmitted by the base station 20). The ratio of incorrectly omitted WUS monitoring opportunities to the transmitted WUSs should not exceed the allowable WUS missed detection rate.

[0102] In another embodiment, UE 100 sends a request to the base station 200 to disable the WUS feature using WUS statistics. For example, this can be done when UE 100 has statistics indicating that it always receives WUS in most of the WUS monitoring occasions. In this case, according to the present invention, UE 100 will skip WUS monitoring in any case and perform PDCCH monitoring during each OnDuration of the DX cycle.

[0103] WUS transmission pattern

[0104] The WUS transmission is defined according to several configuration parameters. For example, DCI-based WUS includes BWP, several CORESETs, several search space configurations, and aggregation level (AL), etc. In this regard, UE 100 can also try to learn the WUS behavior of the base station 200 in order to optimize its power efficiency. For example, if UE 100 is configured with two CORESETs for monitoring WUS, but UE 100 identifies that the base station 200 always transmits WUS in a specific CORESET or 90% of the time in a specific CORESET, then the base station 200 can use this knowledge to narrow its search or modify its hardware parameters to save additional power by first monitoring the specific CORESET where WUS reception is most likely to occur. This aspect can be extended to the cases of search space monitoring or possible AL values. For example, UE 100 can notice that the base station 200 usually transmits WUS with a specific AL or the minimum AL or the maximum AL.

[0105] In one embodiment, UE 100 learns the WUS transmission pattern of the base station 200 by learning the behavior of the base station 200 in a multi-beam scenario. For example, if UE 100 identifies that the base station 200 always transmits WUS in the most recent TCI state (beam) or with a probability higher than a specific threshold, then UE 100 can configure its receiver to monitor WUS only in that TCI state. UE 100 can further design robust techniques to avoid potential misalignment with the base station 20. For example, UE 100 can monitor the SSB and identify that the channel quality in the most recent known TCI state may have deteriorated, and thus, even if no WUS is received, UE 100 ignores the detection result and decides to wake up.

[0106] In a related method, for each TCI state or any other similar TCI state WUS configuration, UE 100 configured with multiple CORESETs can learn the behavior of the base station 200 regarding WUS transmission for each specific TCI state configuration and optimize its own WUS monitoring to achieve power savings.

[0107] WUS command statistics

[0108] In addition to waking up the UE 100, it is also possible that the WUS includes certain commands that the UE 100 should follow. For example, these commands can specify the configuration in which the UE 100 should wake up (e.g., BWP, AL, etc.), or the actions that the UE 100 should take when waking up (e.g., sending an acknowledgment (ACK), CSI report, etc.). In one embodiment, the UE 100 uses WUS statistics to determine the configuration that the UE 100 should use when waking up. For example, if according to historical data, the WUS command specifies that the UE 100 should wake up in BWP1 80% of the time and in BWP2 20% of the time, then when the UE 100 wakes up autonomously, the UE 100 can always wake up in BWP1, or the UE 100 can wake up with this probability (80% in BWP1, 20% in BWP2). This can be extended to other possible configurations, such as the number of layers, etc.

[0109] In addition, the UE 100 may also use statistics on the WUS command to minimize unnecessary measurements. For example, if the UE 100 is RRC-configured to have a maximum transmission layer number equal to 4, and it is known from WUS statistics that it is always (or with a probability exceeding a certain threshold) woken up in two-layer transmission, then the UE 100 may omit the measurement of four-layer transmission (e.g., CSI-RS, SSB), and instead, only perform measurements on two-layer transmission.

[0110] In some embodiments, the UE 100 can also use statistics on the WUS command to prepare for data reception / transmission on an additional component carrier (CC) in carrier aggregation (CA) mode. If the WUS command frequently or according to a consistent pattern indicates data on some or all secondary cells (SCells), then those SCells can be prepared for activation in advance. On the other hand, if an SCell has not been called in the WUS all the time, the SCell-related radio frequency (RF) hardware can be maintained in an inactive hardware state.

[0111] In other embodiments, the UE 100 can use historical data related to the WUS for the UE 100 to prepare for certain actions. For example, if the base station 200 may use the WUS command to request the UE 100 to send a CSI report, then the UE 100 can prepare the necessary actions (e.g., hardware preparation) in advance for uplink transmission, instead of waiting until the WUS is successfully detected / decoded.

[0112] In some embodiments, the UE 100 can select or set UE parameters for UE procedures based on WUS statistics.

[0113] In yet another aspect, the present disclosure defines actions that the UE 100 can take based on those statistics, e.g., skip monitoring of the configured WUS or ignore its content, prepare or skip preparation for additional commands carried by the WUS, etc.

[0114] Extension

[0115] Since the present invention is based on past statistics and probabilistic considerations, it is possible that, in some cases, the actions selected by the UE 100 may prove to be sub-optimal. In one embodiment, the UE 100 tracks power consumption based on the selected special action, e.g., omitting WUS reception, and always monitors the OnDuration, and if the default action will be performed, e.g., monitoring the configured WUS, estimates the power consumption in parallel. If the selected action is sub-optimal power from the perspective of power consumption, e.g., the power consumption difference exceeds a threshold, the UE 100 may revert to the default action. Note that omitting WUS monitoring has no adverse performance impact, only an impact on the power consumption of the UE 100.

[0116] In a related embodiment, the UE 100 may also evaluate the impact of the selected action regarding preparing for an expected WUS command, where some performance impacts may occur due to incorrect prediction, e.g., when the UE 100 is not prepared for higher layer operations or measurements. The UE 100 estimates the difference rate between the predicted and actual WUS commands, and if the incorrect prediction rate or their estimated performance impacts exceed a threshold, may revert to the default behavior of preparing for all possible WUS commands.

[0117] In some embodiments, if a change in the traffic pattern is detected (at L1) or anticipated (e.g., based on application layer information from a smart phone application), the UE 100 may exit the special action mode. The UE 100 may then repeat the base station 200 behavior learning process for the new traffic pattern to determine new suitable special actions.

[0118] Figure 5 An exemplary method 400 implemented by a DRX-implemented UE 100 is shown for preemptively adapting UE processes, such as WUS monitoring processes and / or PDCCH monitoring processes, using statistical characteristics of the WUS transmitted by the base station 200. Method 300 assumes that the UE 100 is in the RRC_Connected state and has PDCCH monitoring and WUS monitoring configured. The default behavior of the UE 100 is to wake up during the WUS monitoring occasion to monitor the WUS. If the WUS is detected, the UE 100 wakes up during the next OnDuration of the DRX cycle to monitor the PDCCH. In Figure 5In method 400 as shown, UE behavior is modified based on statistical characteristics of the WUS transmitted by the base station. UE 100 determines the statistical characteristics of the WUS transmitted by base station 200 (block 410), and preemptively adapts UE procedures based on the statistical characteristics of the WUS transmitted by base station 200 (block 420).

[0119] In some embodiments of method 400, UE 100 adapts default WUS and PDCCH monitoring procedures based on the statistical characteristics of the WUS transmitted by base station 20. In one example, UE 100 selectively monitors WUS monitoring opportunities before the OnDuration of the DRX cycle for WUS based on the statistical characteristics of the WUS transmitted by the base station. When skipping the monitoring of the WUS monitoring opportunity, UE 100 further wakes up and monitors the downlink control channel during the corresponding OnDuration of the DRX cycle.

[0120] In some embodiments of method 400, selectively monitoring the WUS monitoring opportunity includes skipping the monitoring of the WUS monitoring opportunity and waking up to monitor the PDCCH during the corresponding OnDuration of the DRX cycle.

[0121] In some embodiments of method 400, the statistical characteristic is the reception rate of the WUS, and UE 100 selectively monitors the WUS monitoring opportunity depending on the WUS reception rate. In one embodiment, the reception rate is the average of the WUS monitoring opportunities between detections of consecutive WUSs. In another embodiment, the reception rate is the number of WUSs detected over a period of time divided by the total number of WUS monitoring opportunities. This period of time may include, for example, the duration of an RRC connection. In yet another embodiment, the reception rate includes the number of DRX cycles between the transmission of a scheduling request by the user equipment and the detection of the WUS.

[0122] In some embodiments of method 400, the WUS reception rate is traffic type specific, and wherein the UE selectively monitors the WUS monitoring opportunity depending on the current traffic type and the reception rate of the current traffic type. In other embodiments of method 400, the WUS reception rate is specific to the DRX configuration, and wherein the UE selectively monitors the WUS monitoring opportunity depending on the current DRX configuration and the reception rate of the current DRX configuration.

[0123] In some embodiments of method 400, selectively monitoring the WUS monitoring opportunity further depends on the WUS detection rate. If the adaptation of WUS monitoring negatively affects the WUS detection rate, the adaptation may be modified.

[0124] In some embodiments of method 400, selectively monitoring the WUS monitoring occasion includes monitoring resources for WUS monitoring in an order determined based on statistical characteristics of WUS transmissions. Resources for WUS transmissions may include, for example, a bandwidth part, a CORESET, a TCI state, or a beam. As an example, the statistical characteristics of WUS transmissions are specific to the TCI state, and the UE monitors resources for WUS monitoring in an order depending on the current TCI state.

[0125] Some embodiments of method 400 further include determining the power consumption or power savings resulting from a particular WUS monitoring action, and further adapting WUS monitoring based on the power consumption or power savings associated with the WUS monitoring action.

[0126] In some embodiments of method 400, pre-emptively adapting UE procedures based on statistical characteristics of the WUS transmitted by the base station includes adapting PDCCH monitoring depending on the statistical characteristics of the WUS transmitted by the base station. Adapting PDCCH monitoring may include, for example, setting the aggregation level for PDCCH monitoring, or selecting a PDCCH search space from a configured search space.

[0127] In some embodiments of method 400, pre-emptively adapting UE procedures based on statistical characteristics of the WUS transmitted by the base station includes pre-emptively setting parameters to perform UE procedures depending on the statistical characteristics of WUS transmissions.

[0128] In some embodiments of method 400, pre-emptively adapting UE procedures based on statistical characteristics of the WUS transmitted by the base station includes setting parameters for measurement reporting depending on the statistical characteristics of WUS transmissions. For example, UE 100 may pre-emptively set the number of transport layers for measurement reporting.

[0129] In some embodiments of method 400, pre-emptively adapting UE procedures based on statistical characteristics of the WUS transmitted by the base station includes selecting one or more secondary cells for carrier aggregation depending on the statistical characteristics of WUS transmissions.

[0130] Some embodiments of method 400 further include determining the power consumption or power savings attributable to the pre-emptive adaptation, and modifying the pre-emptive adaptation based on the power consumption or power savings associated with the pre-emptive action.

[0131] The device may perform any of the methods described herein by implementing any functional component, module, unit, or circuitry. For example, in one embodiment, the device includes corresponding circuitry or circuitry configured to perform the steps shown in the method diagrams. Such circuitry or circuitry may include, in this regard, circuitry dedicated to performing certain functional processing and / or one or more microprocessors along with memory. For example, the circuitry may include one or more microprocessors or microcontrollers, as well as other digital hardware, which may include a digital signal processor (DSP), dedicated digital logic, etc. The processing circuitry may be configured to execute program code stored in the memory, which may include one or more types of memory, such as read-only memory (ROM), random access memory, cache memory, flash memory devices, optical storage devices, etc. In several embodiments, the program code stored in the memory may include program instructions for performing one or more telecommunication and / or data communication protocols, as well as instructions for implementing one or more of the techniques described herein. In embodiments employing memory, the memory stores program code that, when executed by one or more processors, performs the techniques described herein.

[0132] Figure 6 illustrates a UE 100 configured to perform Figure 4 method 300 according to an embodiment. The UE 100 includes an antenna array 110 having one or more antennas 115, a WUS monitoring unit 120, and a PDCCH monitoring unit 130. The various units 120 - 130 may be implemented by hardware and / or software code executed by one or more processors or processing circuitry. The WUS monitoring unit 120 is configured to selectively monitor a WUS monitoring occasion before the OnDuration of a DRX cycle for WUS depending on a predetermined criterion (e.g., the current UE context). The PDCCH monitoring unit 130 is configured to monitor the PDCCH when the monitoring of the WUS monitoring occasion is skipped by the WUS monitoring unit 120.

[0133] Figure 7 illustrates a UE configured to perform Figure 5UE 100 of method 300. The UE 100 includes an antenna array 110 having one or more antennas 115, a determination unit 140, and an adaptation unit 150. The various units 140-150 may be implemented by hardware and / or software code, and the software code is executed by one or more processors or processing circuitry. The WUS monitoring unit 140 is configured to selectively monitor a WUS monitoring occasion before the OnDuration of a DRX cycle for a WUS depending on a predetermined criterion (e.g., a current UE context). The PDCCH monitoring unit 150 is configured to monitor the PDCCH during the next OnDuration of the DRX cycle when a WUS is detected during the WUS occasion.

[0134] Figure 6 and 7 The embodiments of the UE 100 shown in may be combined in a single UE 100. That is, the UE 100 according to another embodiment may include the antenna array 110 having one or more antennas 115, the WUS monitoring unit 120, the PDCCH monitoring unit 130, the determination unit 140, and the adaptation unit 150 as described above.

[0135] Figure 8 A UE 500 according to one embodiment is shown, which may be configured to implement WUS monitoring as described herein. The UE 500 includes an antenna array 510 having one or more antenna elements 515, an interface circuit 520, a processing circuitry 530, and a memory 540.

[0136] The interface circuit 520 is coupled to the antenna 515 and includes radio frequency (RF) circuitry required to transmit and receive signals over a wireless communication channel. The RF circuitry may also be capable of enabling direct communication with other UEs via a sidelink. In one exemplary embodiment, the interface circuit includes an RF transceiver that includes a transmitter and a receiver configured to operate according to a 5G or NR standard. In some embodiments, the interface circuitry may further be capable of enabling a connection to a wireless local area network (WLAN).

[0137] The processing circuitry 530 controls the overall operation of the UE 500 and processes signals transmitted to or received by the UE 500. Such processing includes tasks such as encoding and modulating data signals to be transmitted and demodulating and decoding received data signals. The processing circuitry 530 is configured to execute one or more of the methods 300, 400 shown respectively in Figure 4 and Figure 5 The processing circuitry 530 may include one or more microprocessors, hardware, firmware, or a combination thereof.

[0138] The memory 540 includes both volatile and non-volatile memories for storing computer program code and data required for operation by the processing circuitry 530. The memory 540 can include any tangible, non-transitory computer-readable storage medium for storing data, including electronic, magnetic, optical, electromagnetic, or semiconductor data storage devices. The memory 540 stores a computer program 550 including executable instructions that configure the processing circuitry 530 to implement one or more of the methods 300, 400 shown respectively in Figure 4 and 5 . The computer program may, in this regard, include one or more code modules corresponding to the above-described components or units. Generally, the computer program instructions and configuration information are stored in non-volatile memory such as ROM, erasable programmable read-only memory (EPROM), or flash memory. Temporary data generated during operation may be stored in volatile memory such as random access memory (RAM). In some embodiments, the computer program 550 for configuring the processing circuitry 530 as described herein may be stored in a removable memory such as a portable compact disc, portable digital video disc, or other removable medium. The computer program 550 may also be embodied in a carrier such as an electronic signal, optical signal, radio signal, or computer-readable storage medium.

[0139] Those skilled in the art will also appreciate that the embodiments herein further include corresponding computer programs. The computer program includes instructions that, when executed on at least one processor of the device, cause the device to perform any of the above-described corresponding processes. The computer program may, in this regard, include one or more code modules corresponding to the above-described components or units.

[0140] The embodiments further include a carrier containing such a computer program. The carrier may include one of an electronic signal, optical signal, radio signal, or computer-readable storage medium.

[0141] In this regard, the embodiments herein also include a computer program product stored on a non-transitory computer-readable (storage or recording) medium and including instructions that, when executed by a processor of the device, cause the device to perform as described above.

[0142] The embodiments further include a computer program product that includes a program code portion for performing the steps of any of the embodiments herein when the computer program product is executed by a computing device. This computer program product may be stored on a computer-readable recording medium.

[0143] The techniques described herein enable more efficient UE power consumption and avoid PDCCH reception quality degradation, especially when the WUS reliability is rather limited. Additionally, the techniques described herein utilize WUS statistics to assist the UE such that the UE can actively perform efficient procedures related to WUS monitoring and efficient responses to WUS commands, and thereby optimize UE power consumption and reduce the network cost caused by unsuccessful WUS detections.

Claims

1. A method for wake signal monitoring implemented by a user equipment (UE) during a discontinuous reception (DRX) mode, the method comprising: Determining statistical characteristics of a wake signal transmitted by a base station; And Pre-emptively adapting UE procedures based on the statistical characteristics of the wake signal transmitted by the base station, wherein pre-emptively adapting UE procedures based on the statistical characteristics of the wake signal transmitted by the base station comprises: Based on the statistical characteristics of the wake signal transmitted by the base station, selectively monitoring wake signal monitoring opportunities before an on-duration of a DRX cycle for the wake signal; and When skipping the monitoring of the wake signal monitoring opportunity, waking up and monitoring a downlink control channel during the corresponding on-duration of the DRX cycle.

2. The method according to claim 1, further comprising: When a wake signal is detected during the wake signal monitoring opportunity, monitoring a downlink control channel during the next on-duration of the DRX cycle.

3. The method according to claim 1 or 2, further comprising: Determining a reception rate of the wake signal and selectively monitoring the wake signal monitoring opportunity depending on the wake signal reception rate.

4. The method according to claim 3, wherein, The wake signal reception rate includes an average number of wake signal monitoring opportunities between detections of consecutive wake signals.

5. The method according to claim 3, wherein, The wake signal reception rate includes a number of wake signals detected over a period of time divided by a total number of wake signal monitoring opportunities.

6. The method according to claim 5, wherein The period of time is a duration of a radio resource control connection.

7. The method according to claim 3, wherein, The wake signal reception rate includes a number of DRX cycles between transmission of a scheduling request of the user equipment and detection of a wake signal.

8. The method according to any one of claims 3-7, wherein, The wake signal reception rate is traffic type specific, and wherein the UE selectively monitors the wake signal monitoring opportunity depending on a current traffic type and a reception rate of the current traffic type.

9. The method according to any one of claims 3-7, wherein, The wake signal reception rate is specific to a DRX configuration, and wherein the UE selectively monitors the wake signal monitoring opportunity depending on a current DRX configuration and a reception rate of the current DRX configuration.

10. The method according to any one of claims 1-9, wherein, Selectively monitoring the wake signal monitoring opportunity further depends on a wake signal detection rate.

11. The method according to claim 1, wherein Selectively monitoring the wake signal monitoring opportunity includes monitoring resources for wake signal monitoring in an order determined based on statistical characteristics of wake signal transmission.

12. The method according to claim 11, wherein, The resources include a bandwidth part or a CORESET.

13. The method according to claim 11, wherein, The resources include a TCI state or a beam.

14. The method according to any one of claims 11 - 13, wherein, The statistical characteristics of wake signal transmission are specific to a TCI state, and wherein the UE monitors resources for the wake signal monitoring in an order depending on a current TCI state.

15. The method according to any one of claims 1-14, further comprising: Determining power consumption or power savings resulting from a specific wake signal monitoring behavior; Further adapting wake signal monitoring based on the power consumption or power savings associated with the wake signal monitoring behavior.

16. The method according to claim 1, wherein Pre-emptively adapting UE procedures based on the statistical characteristics of the wake signal transmitted by the base station includes adapting downlink control channel monitoring depending on the statistical characteristics of the wake signal transmitted by the base station.

17. The method according to claim 16, wherein, Adapting downlink control channel monitoring includes setting an aggregation level for downlink control channel monitoring.

18. The method according to claim 16, wherein, Pre-emptively adapting the user equipment to perform a process includes pre-emptively selecting a downlink control channel search space.

19. The method according to claim 1, wherein, Pre-emptively adapting UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station includes pre-emptively setting parameters to perform the UE processes depending on the statistical characteristics of the wake-up signal transmission.

20. The method according to claim 1, wherein, Pre-emptively adapting UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station includes configuring or adapting measurement reports depending on the statistical characteristics of the wake-up signal transmission.

21. The method according to claim 20, wherein, Pre-emptively configuring or adapting measurement reports includes setting the number of transport layers for measurement reports.

22. The method according to claim 1, wherein, Pre-emptively adapting UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station includes selecting one or more secondary cells for carrier aggregation depending on the statistical characteristics of the wake-up signal transmission.

23. The method according to any one of claims 1-22, further comprising: Determining the power consumption or power savings attributable to the pre-emptive adaptation; Modifying the pre-emptive adaptation based on the power consumption or power savings associated with the pre-emptive action.

24. A user equipment (UE) in a wireless communication network, comprising: Communication circuitry for communicating with a wireless communication network; Processing circuitry operable to: Determine the statistical characteristics of a wake-up signal transmitted by a base station; and Pre-emptively adapt UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station, wherein pre-emptively adapting UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station includes: Selectively monitoring a wake-up signal monitoring opportunity before the on-duration of a DRX cycle for the wake-up signal based on the statistical characteristics of the wake-up signal transmitted by the base station; and When skipping the monitoring of the wake-up signal monitoring opportunity, waking up and monitoring the downlink control channel during the corresponding on-duration of the DRX cycle.

25. The UE according to claim 24, wherein, The processing circuitry is further configured to perform the method according to any one of claims 2-23.

26. A user equipment (UE) in a wireless communication network, the user equipment operable to: Determine the statistical characteristics of a wake-up signal transmitted by a base station; and Pre-emptively adapt UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station, Among them, wherein pre-emptively adapting UE processes based on the statistical characteristics of the wake-up signal transmitted by the base station includes: Selectively monitoring a wake-up signal monitoring opportunity before the on-duration of a DRX cycle for the wake-up signal based on the statistical characteristics of the wake-up signal transmitted by the base station; and When skipping the monitoring of the wake-up signal monitoring opportunity, waking up and monitoring the downlink control channel during the corresponding on-duration of the DRX cycle.

27. The UE according to claim 26, wherein The UE is further configured to perform the method according to any one of claims 2-23.

28. A computer program product, the computer program product comprising a computer program, the computer program comprising executable instructions which, when executed by processing circuitry in a user equipment UE in a wireless communication network, cause the UE to perform the method according to any one of claims 1 - 23.

29. A non - transitory computer - readable storage medium comprising a computer program, the computer program comprising executable instructions which, when executed by processing circuitry in a user equipment UE in a wireless communication network, cause the UE to perform the method according to any one of claims 1 - 23.

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