Radio link monitoring using low power wake-up radio in wireless device

Abstract

The invention relates to wireless communication. Comprising methods and apparatus for adaptively monitoring radio link conditions of a cellular wireless network using a low power wake-up signal (LP-WUS) burst received by a low power wake-up radio (LP-WUR) of a wireless device if possible and switching to using legacy reference signals received by a primary radio only when needed. The LP-WUS burst is processed by the LP-WUR to determine a block error rate (BLER) value and / or a signal to interference plus noise ratio (SINR) value to determine whether the wireless device is in an out-of-sync (OOS) condition. When the OOS condition is determined, the primary radio may be awakened to perform radio link monitoring, including steering into sleep by the cellular wireless network.

Description

Technical Field

[0001] The described embodiments relate to wireless communications, including methods and apparatus for monitoring radio link conditions using a low power wake-up signal (LP-WUS) received by a low power wake-up radio (LP-WUR) of a wireless device. Background Art

[0002] Newer generations (e.g., fifth generation (5G) New Radio (NR)) cellular wireless networks implementing one or more third generation partnership project (3GPP) 5G standards are rapidly developing and being deployed by network operators around the world. Newer cellular wireless networks provide a range of packet-based services, with 5G technology providing increased data throughput and lower latency connections that ensure enhanced mobile broadband services for wireless devices. The higher data throughput and lower latency of 5G are expected to introduce a range of new applications and services and improve existing applications and services. 5G technology is being installed in various types of wireless devices with different power requirements, and low-power sleep modes are expected to extend the battery life of wireless devices. 3GPP 5G wireless communication standard Release 15 introduces a low-power wake-up signal (LP-WUS) to allow the main radio of a wireless device to be in sleep until awakened based on the LP-WUS. The wireless device also needs to monitor the radio link status of the cellular wireless network and report the measurement results at fixed intervals. Using the main radio of the wireless device requires higher power consumption than using a separate low-power wake-up radio (LP-WUR) that may be included in the wireless device. A mechanism is needed for the wireless device to adaptively monitor the radio link status using the LP-WUS received by the LP-WUR when possible to save power and switch to monitoring the radio link status using the traditional reference signal received via the primary radio only when necessary. Summary of the invention

[0003] The present application relates to wireless communications, including methods and apparatus for adaptively monitoring radio link conditions of a cellular wireless network using low power wake-up signal (LP-WUS) bursts received by a low power wake-up radio (LP-WUR) of a wireless device to save power when possible and switching to monitoring radio link conditions using traditional reference signals received by a primary radio of the wireless device only when necessary. The primary radio may be placed in a sleep state and awakened to the awake state based on information included in one or more received LP-WUS bursts. The wireless device may perform radio link monitoring (RLM) in a radio resource control (RRC) connected state by processing a synchronization portion of the LP-WUS burst to determine an evaluation result, such as an LP-WUS block error rate (BLER) value and / or an LP-WUS signal to interference plus noise ratio (SINR) value, while the primary radio is in a sleep state. The evaluation result calculated from the LP-WUS may be compared with a corresponding threshold to determine whether to wake up the primary radio of the wireless device, thereby performing RLM using an additional signal (e.g., a traditional reference signal) received via the primary radio. The LP-WUS burst includes N LP-WUS repetitions, and the wireless device can determine the evaluation result by processing M≤N LP-WUS repetitions on the evaluation window and repeating the LP-WUS processing by gradually sliding the evaluation window on the LP-WUS burst. The wireless device performs RLM using the received signal of a single LP-WUS burst without combining the received signals of separate LP-WUS bursts. Based on the legacy signal received via the main radio, the thresholds of LP-WUS LER and LP-WUS SINR may be different from the corresponding BLER and SINR thresholds used for RLM. In some embodiments, the LP-WUS BLER threshold for determining an out-of-sync (OOS) condition is lower than the BLER threshold based on the legacy signal, and the LP-WUS SINR threshold for determining the OOS condition is higher than the SINR threshold based on the legacy signal. Compared with using a legacy reference signal, a lower LP-WUS LER threshold (at or above which an OOS condition can be determined) and a higher LP-WUS SINR threshold (at or below which an OOS condition can be determined) provide a faster OOS determination using an LP-WUS burst. When the wireless device determines an OOS condition based on an LP-WUSBLER or LP-WUS SINR value satisfying a corresponding threshold, the wireless device wakes up the primary radio, including when the LP-WUS burst indicates that the primary radio should remain in a sleep state. The wireless device sends a notification to the cellular wireless network to indicate that the state of the primary radio of the wireless device has changed from a sleep state to an awake state. Subsequently, when the primary radio is in the awake state, the wireless device may perform RLM using a legacy reference signal received via the primary radio.When the primary radio is in a sleep state, the wireless device performs RLM using LP-WUS bursts, and when the primary radio is in an awake state, the wireless device performs RLM using legacy reference signals (e.g., synchronization symbol blocks (SSBs) and / or channel state information reference signals (CSI-RS)). In some embodiments, the wireless device performs RLM monitoring after waking the primary radio to the awake state using a relaxed RLM schedule that extends the evaluation period and / or measurement reporting interval by a positive factor K>1 compared to a normal non-relaxed RLM schedule. In some embodiments, when RLM measurements using legacy reference signals indicate an OOS condition, the wireless device switches from using the relaxed RLM schedule to the normal non-relaxed RLM schedule. In some embodiments, the BLER threshold for switching from relaxed RLM scheduling to normal non-relaxed RLM scheduling requires that the BLER measurement exceeds the BLER threshold for determining an OOS condition, which is adjusted lower by a negative BLER offset threshold (or equivalently, a positive BLER offset threshold is added to the BLER measurement and the adjusted BLER measurement is compared to the normal OOS BLER threshold).

[0004] Other aspects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate by way of example the principles of the described embodiments.

[0005] The present invention content is provided only for the purpose of summarizing some example embodiments, so as to provide a basic understanding of some aspects of the subject matter described herein. Therefore, it should be understood that the above-mentioned features are only examples and should not be construed as narrowing the scope or essence of the subject matter described herein in any way. Other features, aspects and advantages of the subject matter described herein will become apparent through the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure will be more readily understood through the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals designate like structural elements.

[0007] Figure 1 A block diagram of different components of an exemplary system configured to perform radio link monitoring (RLM) by a wireless device is shown in accordance with some embodiments.

[0008] Figure 2A A diagram illustrating an exemplary power reduction mechanism for a wireless device according to some embodiments.

[0009] Figure 2B Additional diagrams illustrating exemplary power reduction mechanisms for wireless devices according to some embodiments.

[0010] Figure 3 A diagram illustrating an example of RLM using a low power wake-up signal (LP-WUS) by a wireless device according to some embodiments.

[0011] Figure 4 A diagram illustrating an exemplary configuration of a LP-WUS according to some embodiments.

[0012] Figure 5 A diagram showing an example of adapting to synchronization conditions based on a signal used by a wireless device for RLM according to some embodiments.

[0013] Fig. 6A A diagram illustrating an example of adaptive RLM for a wireless device according to some embodiments.

[0014] Figure 6B A diagram illustrating an exemplary mapping of evaluation results using different radios of a wireless device according to some embodiments.

[0015] Figure 7 A flowchart is shown of an exemplary method for a wireless device to perform RLM according to some embodiments.

[0016] Figure 8 A block diagram of exemplary elements of a wireless device according to some embodiments is shown. DETAILED DESCRIPTION

[0017] Representative applications of the methods and apparatus according to the present application are described in this section. These examples are provided only to add context and aid in understanding the described embodiments. Therefore, it will be apparent to those skilled in the art that the embodiments may be practiced without some or all of these specific details. In other cases, in order to avoid unnecessarily obscuring the embodiments, well-known processing steps are not described in detail. Other applications are possible, so that the following examples should not be considered restrictive.

[0018] The present application relates to wireless communications, including methods and apparatus for adaptively monitoring radio link conditions of a cellular wireless network using low power wake-up signal (LP-WUS) bursts received by a low power wake-up radio (LP-WUR) of a wireless device to save power when possible and switching to using a traditional reference signal received by a main radio of the wireless device only when needed. The main radio includes a wireless circuit for performing data transmission and reception, control signaling, and radio link monitoring (RLM) using traditional reference signals. The LP-WUR includes additional wireless circuits to support limited functionality of the wireless device when the main radio is in a reduced power sleep state. The main radio can be placed in a sleep state and wake up to a wake state based on information included in one or more LP-WUS bursts received and processed by the LP-WUR. The main radio can transition from a sleep state to a wake state or from a wake state to a sleep state based on an indication included in an information portion of an LP-WUS burst received via the LP-WUR. As further discussed herein, the primary radio may also transition from the sleep state to the awake state based on determining radio link conditions from an evaluation of a synchronization portion of an LP-WUS repetition of an LP-WUS burst, including when the information portion of the LP-WUS indicates that the primary radio should be in the sleep state.

[0019] The wireless device may perform radio link monitoring (RLM) in a radio resource control (RRC) connected state by processing a synchronization portion of an LP-WUS repetition of an LP-WUS burst to determine an evaluation result, such as an LP-WUS block error rate (BLER) value and / or an LP-WUS signal to interference plus noise ratio (SINR) value, while the primary radio is in a sleep state. The evaluation result calculated from the LP-WUS may be compared with a corresponding threshold to determine whether to wake up the primary radio of the wireless device, thereby performing RLM using an additional legacy reference signal received via the primary radio. The LP-WUS burst includes N LP-WUS repetitions, and the wireless device may determine the evaluation result by processing M≤N LP-WUS repetitions over an evaluation window and repeating the LP-WUS processing by gradually sliding the evaluation window over the LP-WUS burst. The wireless device may use a sliding step value corresponding to the spacing of each LP-WUS repetition included in the LP-WUS burst. The wireless device performs RLM using a received signal of a single LP-WUS burst without combining received signals of separate LP-WUS bursts.

[0020] Based on the legacy signals received via the primary radio, the thresholds for LP-WUSBLER and LP-WUS SINR may be different from the BLER and SINR thresholds configured by the cellular wireless network and used for RLM. In some embodiments, the LP-WUSBLER threshold for determining an out-of-sync (OOS) condition using LP-WUS when the primary radio is in a sleep state is lower than the BLER threshold based on the legacy signal for determining the OOS condition using the legacy reference signal when the primary radio is in an awake state. In some embodiments, the LP-WUS SINR threshold for determining the OOS condition using LP-WUS when the primary radio is in a sleep state is higher than the SINR threshold based on the legacy signal for determining the OOS condition using the legacy reference signal when the primary radio is in an awake state. The LP-WUSBLER threshold may be equal to the primary radio BLER threshold plus a negative BLER offset value. Similarly, the LP-WUSSINR threshold may be equal to the primary radio SINR threshold plus a positive SINR offset value. The lower LP-WUS SINR threshold (above which an OOS condition may be determined) and the higher LP-WUS SINR threshold (below which an OOS condition may be determined) provide for faster OOS determination using LP-WUS bursts than using conventional reference signals.

[0021] When the wireless device determines an OOS condition based on an LP-WUSBLER value or an LP-WUS SINR value that meets a corresponding threshold, the wireless device wakes up the primary radio, including when the information portion of the LP-WUS burst indicates that the primary radio will remain in a sleep state. The LP-WUS OOS condition overrides the network sleep indication of the primary radio. After waking up the primary radio, the wireless device sends a notification to the cellular wireless network via the primary radio to indicate that the state of the primary radio of the wireless device has changed from a sleep state to an awake state. Subsequently, when the primary radio is in an awake state, the wireless device can perform RLM using a traditional reference signal received via the primary radio, for example, to confirm the OOS condition.

[0022] When the primary radio is in the sleep state, the wireless device performs RLM using LP-WUS bursts, and when the primary radio is in the awake state, the wireless device performs RLM using legacy reference signals (e.g., synchronization symbol blocks (SSBs) and / or channel state information reference signals (CSI-RS)). The wireless device restarts RLM after the primary radio transitions between the sleep state and the awake state, and discards some of the RLM results accumulated before the state transition. When the primary radio is in the sleep state, the wireless device may use a different evaluation time period than when the primary radio is in the awake state. In some embodiments, the wireless device performs RLM monitoring after waking the primary radio to the awake state using a relaxed RLM schedule that extends the evaluation period and / or measurement reporting interval by a positive factor K>1 compared to a normal non-relaxed RLM schedule. In some embodiments, when RLM measurements obtained from legacy reference signals received via the primary radio when in the awake state indicate an OOS condition, the wireless device switches from using a relaxed (lower frequency) RLM schedule to a normal non-relaxed (higher frequency) RLM schedule. In some embodiments, the wireless device switches from using relaxed RLM scheduling to normal non-relaxed RLM scheduling when a BLER measurement obtained using the legacy reference signal plus a positive BLER offset threshold exceeds a primary radio OOS BLER threshold.

[0023] These and other embodiments are referred to below. Figures 1 to 8 Discussion is made; however, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for illustrative purposes only and should not be construed as limiting.

[0024] Figure 1A block diagram 100 of different components of an exemplary system configured to perform radio link monitoring (RLM) is shown. A wireless device 102 includes wireless circuitry including a primary radio 120 and a low power wake-up radio (LP-WUR) 122 and receiving downlink signals from a gNodeB 112 of a cellular wireless network. The primary radio 120 is used for transmission and reception of data and control signals, and for performing radio link monitoring (RLM) using a legacy reference signal 110 received in the downlink direction from the cellular wireless network. The LP-WUR 122 is a low power component for supporting limited functionality including receiving a low power wake-up signal (LP-WUS) 108 that provides an indication from a gNodeB 112 of a cellular wireless network whether to wake the primary radio 120 from a reduced power sleep state. The gNodeB 112 of the cellular wireless network may transmit both the LP-WUS 108 and the legacy reference signal 110 to allow the wireless device 102 to receive and use each type of signal accordingly. The legacy reference signals 110 may include a synchronization symbol block (SSB) including i) a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) used by the wireless device 102 to locate, identify, and synchronize to the cellular wireless network, and ii) physical broadcast channel (PBCH) system information. Additional legacy reference signals 110 may include a demodulation reference signal (DM-RS) for channel estimation, system information (SI) signals such as a channel state information reference signal (CSI-RS) for channel estimation, time tracking, and frequency tracking. When the main radio 120 of the wireless device 102 is in a reduced power sleep state, the LP-WUR 122 cannot be configured to process the legacy reference signals. Since radio link monitoring of the communication channel and wireless environment of the wireless device 102 is required at fixed intervals for normal operation, the wireless device 102 can wake up the main radio 120 to monitor the legacy reference signals; however, using the main radio 120 for RLM consumes additional power, thereby partially offsetting the benefits of the reduced power sleep mode. As described herein, the wireless device 102 may alternatively perform RLM using the LP-WUS 108 and using the LP-WUR 122 to conserve power and cause the primary radio 120 to perform RLM only under certain observed conditions.

[0025] Figure 2A and Figure 2BDiagrams 200, 210, 220, 250, and 260 illustrate various power reduction mechanisms for a wireless device 102. The wireless device 102 may be in one of several defined states, including a radio resource control (RRC) idle state and an RRC connected state. In the RRC idle state, data transmission and reception are not allowed, there is no RRC context established with a cellular wireless network, and there is no connection established with a core network portion of a cellular wireless network; however, the wireless device 102 may receive paging messages. In the RRC connected state, data transmission and reception are allowed, there is an RRC context established with a cellular wireless network, and there is a connection established with a core network portion of a cellular wireless network. Power consumption in the RRC connected state is higher than power consumption in the RRC idle state. The wireless device 102 may be configured for discontinuous reception (DRX) to reduce power consumption in the RRC idle state and the RRC connected state.

[0026] As shown in diagram 200, the wireless device 102 may maintain the primary radio 120 of the wireless device 102 in a sleep state while in an RRC idle DRX (i-DRX) mode, and wake up the primary radio 120 at fixed intervals of the i-DRX cycle to monitor a physical downlink control channel (PDCCH) during a paging occasion (PO) to determine whether downlink data is scheduled to be sent to the wireless device 102. When there is downlink data, the primary radio 120 of the wireless device 102 may remain awake (or wake up at a specific designated time) to receive the downlink data. When there is no downlink data, the primary radio 120 of the wireless device 102 may return to a sleep state.

[0027] As shown in diagram 210, the wireless device 102, when in RRC connected DRX (c-DRX) mode, can wake up the primary radio 120 from a sleep state at fixed intervals of a short DRX cycle to monitor the PDCCH for paging occasions, and maintain the primary radio 120 in a sleep state when there is no downlink data. After a period of time using the short DRX cycle without available data, the wireless device 102 switches to using a long DRX cycle, thereby monitoring the PDCCH for paging occasions with a longer time interval.

[0028] As shown in diagram 220, the wireless device 102 may use an extended DRX cycle (eDRX) after a period of time in c-DRX mode before using i-DRX mode. As the sleep cycle length increases, the responsiveness of the wireless device 102 decreases because the wireless device 102 cannot monitor the paging occasion until it is scheduled according to the DRX cycle being used. As shown in diagram 250, the wireless device 102 may use an extended sleep cycle in power saving mode and cannot be reached by the cellular wireless network in the extended sleep state. To overcome this drawback, the cellular wireless network may use a low power wake-up signal (LP-WUS) 108 before the paging occasion.

[0029] As shown in diagram 260, the wireless device 102 may be configured to allow the primary radio 120 to enter a sleep state after completing data reception, and in some cases, after using a c-DRX state prior to an i-DRX state. When the primary radio 120 is in the sleep state, the wireless device 102 may monitor the LP-WUS 108 using a low power wake-up radio (LP-WUR) 122. When the LP-WUS 108 indicates that the primary radio 120 should wake up from the sleep state, the wireless device 102 may transition the primary radio 120 to the wake state and monitor the PDCCH during subsequent paging occasions. When the LP-WUS 108 indicates that the primary radio 120 should remain in the sleep state, the wireless device 102 may return the LP-WUR to the sleep state and wait for the next LP-WUS 108.

[0030] When in the RRC connected state, the wireless device 102 may need to monitor the radio link channel conditions at the physical layer (layer 1 or L1) and report information (such as synchronization and out-of-sync indications) to higher layer functions. Continuous reporting from the physical layer to higher layers may occur periodically based on a configured reporting interval. The wireless device 102 may use the primary radio 120 to monitor legacy reference signals from the cellular wireless network, such as SSB including PSS / SSS and PBCH, and DM-RS and CSI-RS signals. The primary radio 120 of the wireless device 102 may monitor the legacy reference signals received in multiple instances over an evaluation window (time period), and then report information obtained from processing the legacy reference signals at a reporting (layer 1 indication) interval, which may be based on the wireless device 102 being configured as a power saving mode with a shorter reporting time in active mode and a longer reporting time in DRX mode. To save power, instead of using the primary radio 120 to monitor the legacy reference signal 110 , the wireless device 102 may use the LP-WUR 122 to monitor the LP-WUS 108 , putting the primary radio 120 in a sleep state until certain criteria are met.

[0031] Figure 3A diagram 300 of an exemplary mechanism for the wireless device 102 to perform RLM using the LP-WUS 108 is shown. The cellular wireless network may transmit a LP-WUS burst 252 including N repetitions of the LP-WUS 108. The LP-WUR 122 of the wireless device 102 may monitor the LP-WUS 108 for an indication as to whether the primary radio 120 should remain in a sleep state or enter an awake state. The LP-WUR 122 of the wireless device 102 may process the M repetitions of the LP-WUS 108 over an evaluation window 302 and determine one or more channel metrics by processing the LP-WUS 108 repetitions. In some embodiments, the LP-WUS 108 includes a synchronization portion that may be used to perform channel measurements based on processing the synchronization portion of the LP-WUS 108 to determine a LP-WUS block error rate (BLER) and / or a LP-WUS signal to interference plus noise ratio (SINR). In some embodiments, the LP-WUR 122 of the wireless device 102 determines whether the wireless device 102 is in a synchronized condition or an out-of-sync condition based on a channel metric obtained by monitoring the LP-WUS 108 repetitions. In some embodiments, the LP-WUR 122 of the wireless device 102 performs a repetition evaluation by sliding the evaluation window 302 by a sliding step time interval, which can be associated with a layer 1 (L1) measurement interval and / or a reporting interval. The LP-WUR 122 of the wireless device 102 can receive and process the LP-WUS bursts 252 individually, wherein the individual LP-WUS bursts 252 are separated by an extended LP-WUS inter-burst interval. In some embodiments, the channel metric is obtained by processing only the LP-WUS 108 repetitions within a single LP-WUS burst 252, and the LP-WUS 108 repetitions in LP-WUS bursts 252 that are far apart are not combined. When the number of LP-WUS 108 repetitions in a LP-WUS burst 252 is equal to or less than the number of samples required for RLM evaluation, the wireless device 102 uses all samples of the LP-WUS burst 252 (and does not use samples from other or adjacent LP-WUS bursts 252). In some embodiments, the wireless device 102 uses sample values ​​from LP-WUS 108 repetitions across an evaluation window 302 to average and / or filter, and limits the averaging and / or filtering to sample values ​​of a single LP-WUS burst 252, i.e., does not perform averaging and / or filtering across LP-WUS bursts 252. When the number of LP-WUS 108 repetitions in a LP-WUS burst 252 exceeds the number of samples required for RLM evaluation, the LP-WUR 122 of the wireless device 102 may average / filter across an evaluation window 302 that spans the number of samples required for RLM evaluation, and then repeat the evaluation by sliding the evaluation window 302 by a step interval (e.g., one LP-WUS 108 repetition) and repeating the RLM evaluation.

[0032] Figure 4 Diagrams 400, 410, and 420 illustrate example configurations of different portions of the LP-WUS 108. The LP-WUS 108 includes a synchronization portion 402, which may be a synchronization sequence and may be used for synchronization, timing, and frequency tracking of the LP-WUR 122 of the wireless device 102. The LP-WUS 108 also includes an information portion 404, which may provide a dormancy (sleep / wake state) indication to the primary radio 120 of the wireless device 102. When the information portion 404 of the LP-WUS 108 indicates that the primary radio 120 of the wireless device 102 is to remain in (or enter) a dormant state, the LP-WUR 122 of the wireless device 102 may process the synchronization portion of the LP-WUS 108 to determine one or more wireless channel measurements. When the information portion 404 of the LP-WUS 108 indicates that the primary radio 120 of the wireless device 102 is to enter an awake state, the primary radio 120 of the wireless device 102 may be used to determine one or more wireless channel measurements using one or more legacy reference signals 110. In some embodiments, the LP-WUR 122 of the wireless device 102 handles the synchronization portion of the LP-WUS 108 to perform synchronization, timing, and frequency tracking functions while the main radio 120 of the wireless device 102 remains in a sleep state. The LP-WUS 108 can use different configurations in the time and frequency dimensions, such as using a common set of radio frequencies at different time intervals, as shown in diagram 400; using a common time interval across different radio frequency bands, as shown in diagram 410; or using separate time intervals and different radio frequency bands, as shown in diagram 420.

[0033] Figure 5Diagrams 500, 510 are shown for determining an in-sync or out-of-sync (OOS) condition of a wireless device 102 using selected wireless channel measurements. A different threshold may be used when processing a legacy reference signal 110 than when processing an LP-WUS repetition 108 of an LP-WUS burst 252. When a master radio 120 of a wireless device 102 determines a block error rate (BLER) value using the legacy reference signal 110, the master radio 120 may determine an in-sync 502 condition of the wireless device 102 when the BLER meets (e.g., is equal to or falls below) a low BLER threshold percentage value, and the master radio 120 may determine an out-of-sync (OOS) 504 condition of the wireless device 102 when the BLER meets (e.g., is equal to or exceeds) a high BLER threshold percentage value. A representative high BLER threshold percentage value (at or above which an OOS condition may be determined) may be 10%, and a representative low BLER threshold percentage value (at or below which an out-of-sync condition may be determined) may be 2%. Between the low BLER threshold value and the high BLER threshold value, the main radio 120 of the wireless device 102 may maintain the previously determined synchronization / OOS condition. In some embodiments, the cellular wireless network associated with the wireless device 102 may set a low BLER and / or high BLER threshold percentage value. When the LP-WUR 122 of the wireless device 102 uses the LP-WUS 108 repetition of the LP-WUS burst 252 to determine the LP-WUSBLER value, when the LP-WUSBLER meets (e.g., is equal to or falls below) the low LP-WUSBLER threshold percentage value, the LP-WUR 122 may determine the synchronization 502 condition of the wireless device 102, and the low LP-WUSBLER threshold percentage value may be higher than the low BLER threshold percentage value used for traditional reference signal radio link monitoring. The offset allows the LP-WUR 122 to transition from the OOS condition to the synchronization condition more quickly. Similarly, when the LP-WUR 122 of the wireless device 102 determines the LP-WUSBLER value using the LP-WUS 108 repetitions of the LP-WUS burst 252, the LP-WUR 122 may determine an out-of-sync (OOS) 504 condition of the wireless device 102 when the LP-WUSBLER meets (e.g., equals or exceeds) a high LP-WUSBLER threshold percentage value that may be a negative offset, e.g., X% lower, than a corresponding high BLER threshold percentage value used for traditional reference signal monitoring. The offset may allow the LP-WUR 122 to transition from an in-sync condition to an OOS condition more quickly.A representative high LP-WUSBLER threshold percentage value (at or above which an OOS condition may be determined) may be 10-X%, while a representative low LP-WUS BLER threshold percentage value (at or below which an out-of-sync condition may be determined) may be 2+Y%. Between the low LP-WUSBLER threshold value and the high LP-WUSBLER threshold value, the primary radio 120 of the wireless device 102 may maintain a previously determined in-sync / OOS condition.

[0034] In some embodiments, the wireless device 102 estimates SINR values ​​using the LP-WUS 108 repetitions of the LP-WUS burst 252, and uses the estimated SINR values ​​alone or in combination with the LP-WUS BLER to determine whether to declare an in-sync condition or an OOS condition for the wireless device 102. In some embodiments, a cellular wireless network associated with the wireless device 102 may set a low SINR value threshold and / or a high SINR threshold value for the wireless device 102 to use when measuring the legacy reference signal 110. The wireless device 102 may determine adjusted low and high LP-WUS SINR threshold values ​​to use based on the network configured low SINR threshold and high SINR threshold values, for example, by adding an offset to the low SINR threshold value (above which an OOS condition may be determined) and / or by subtracting an offset from the high SINR threshold value (above which an in-sync condition may be determined).

[0035] The wireless device 102 may use both the primary radio 120 and the LP-WUR 122 to monitor the radio link condition at different times, and switch between the use of the LP-WUR 122 and the use of the primary radio 120 based on the selection criteria that are satisfied. In some embodiments, when the information portion of the LP-WUS 108 indicates that the primary radio 120 should remain asleep, the LP-WUR 122 uses the LP-WUS 108 repetitions of the LP-WUS burst 252 to monitor the radio link condition. In some embodiments, when one or more repetitions of the information portion of the LP-WUS burst 252 indicate that the primary radio 120 should wake up from the sleep state and transition to the awake state, the LP-WUR 122 wakes the primary radio 120 from the sleep state to the awake state and monitors the radio link condition using the legacy reference signal 110. In some embodiments, when the LP-WUSBLER satisfies the low LP-WUSBLER threshold (indicating an OOS condition), the wireless device 102 wakes up the primary radio 120 from the sleep state to the awake state and monitors the radio link condition using the legacy reference signal 110, regardless of whether the information portion of the LP-WUS 108 indicates that the primary radio 120 should remain asleep. The wireless device 102 may similarly use an SINR threshold to determine whether to wake up the primary radio 120 from the sleep state, instead of or in addition to the BLER threshold.

[0036] It is expected that the accuracy of the measurement of the radio link condition using the primary radio 120 and the legacy reference signal 110 will be higher than the accuracy of the measurement of the radio link condition using the LP-WUR 122 and the LP-WUS burst 252. In some embodiments, when the LP-WUSBLER and / or LP-WUS SINR values ​​meet the LP-WUSBLER threshold value or the LP-WUS SINR threshold value for declaring an OOS condition, the LP-WUR 122 wakes the primary radio 120 from the sleep state regardless of the indication to remain in the sleep state included in the information portion of the LP-WUS 108 repetition of the LP-WUS burst 252. In some embodiments, the wireless device 102 adds an offset margin (e.g., an additional Z%) to the LP-WUSBLER threshold value for determining whether to wake the primary radio 120 from the sleep state. In some embodiments, the wireless device 102 requires a lower LP-WUS SINR threshold value (e.g., Z% lower than normal) in order to determine to wake the primary radio 120 from the sleep state. In the event that the measured LP-WUSBLER increases and the radio link condition deteriorates, when the primary radio 120 is in a sleep state, the wireless device 102 may first determine an OOS condition (e.g., when the LP-WUS BLER crosses a LP-WUSBLER threshold value), and then may determine to wake up the primary radio 120 from the sleep state (e.g., when the LP-WUSBLER crosses a higher (Z%) LP-WUS BLER threshold value). Once the primary radio 120 is awakened, the wireless device 102 may use the received legacy reference signal 110 to determine whether the OOS condition is valid. Similarly, in some embodiments, the wireless device 102 may use the adjusted SINR value to determine whether to wake up the primary radio 120 from the sleep state. In some embodiments, the offset value (e.g., Z%) for the adjusted LP-WUSBLER threshold or the adjusted LP-WUS SINR threshold (for waking up the primary radio 120) may be pre-configured in the wireless device 102 or configured by the cellular wireless network.

[0037] In some embodiments, when the wireless device 102 switches between monitoring the radio link status using the legacy reference signal 110 and the LP-WUS 108 repetition using the LP-WUS burst 252, the accumulated data, partial measurements, and / or historical measurements may be discarded or ignored. In some embodiments, the determination of synchronization or OOS may be based only on measurements made using the legacy reference signal 110 or using the LP-WUS burst 252, but the measurement results of both are not mixed. In some embodiments, the evaluation time period (e.g., the length of the evaluation window over which the measurement results can be obtained, averaged, and / or filtered) is based on the signal used for measurement. Therefore, the evaluation time period of the legacy reference signal 110 and the evaluation period of the LP-WUS burst 252 may be different. When switching to RLM using the LP-WUS burst 252, the evaluation samples obtained using one type of signal (e.g., based on the legacy reference signal 110) may be discarded. Similarly, when switching to RLM using the legacy reference signal 110, the evaluation samples obtained based on the LP-WUS burst 252 may be discarded.

[0038] The LP-WUS burst 252 may communicate at a different power level than the power level of the legacy reference signal 110, and thus RLM measurements using the LP-WUS burst 252 may differ from RLM measurements based on the legacy reference signal 110. LP-WUS based parameters and threshold values ​​may be scaled based on the power difference between the time / frequency resource elements of the LP-WUS burst 252 and the corresponding time / frequency resource elements used by the legacy reference signal. In some embodiments, the average LP-WUS resource element (RE) energy level may be 4+K dB lower than the physical downlink control channel (PDCCH) RE. In some embodiments, the average LP-WUS RE energy level may be 4+K dB lower than the PDCCH downlink modulation reference signal (DM-RS) energy level.

[0039] In some embodiments, the cellular wireless network configures multiple receive antennas (e.g., one antenna, two antennas, etc.) for use with the LP-WUS burst 252 for radio link monitoring or other measurements. In some embodiments, the number of receive antennas used for RLM using the LP-WUS burst 252 is preconfigured based on the 3GPP wireless communication standard.

[0040] In addition to layer 1 (L1) radio link monitoring, the wireless device 102 may also perform layer 3 (L3) measurements. In some cases, L1 RLM and L3 measurements may be separately scheduled at different periods. In some cases, the time period of L1 RLM measurements may overlap (collide) with the time period of L3 measurements. In some embodiments, L3 measurements based on LP-WUS bursts 252 may take precedence over L1 RLM measurements based on LP-WUS bursts 252. In some embodiments, L1 RLM measurements based on LP-WUS bursts 252 may take precedence over L3 measurements based on legacy reference signals 110.

[0041] Fig. 6A A diagram 600 of adaptive RLM is shown when the primary radio 120 of the wireless device 102 processes the legacy reference signal 110. As discussed herein, the wireless device 102 may wake up the primary radio 120 from a sleep state in response to determining a high BLER, low SINR, or OOS condition (based on RLM using LP-WUS bursts 252). The cellular wireless network may continue to send LP-WUS bursts 252 that indicate that the primary radio 120 should be in a sleep state; however, the wireless device 102 may keep the primary radio 120 in an awake state to perform RLM using the legacy reference signal 110 (which cannot be processed by the LP-WUS 122 of the wireless device 102). The wireless device 102 may use an extended (relaxed) evaluation time period and / or layer 1 (L1) reporting interval in relaxed mode 602, for example, scaling the evaluation time period using a positive factor K>1 and / or scaling the L1 interval using a positive factor K>1. When the BLER measurement result meets the BLER threshold for OOS conditions (or exceeds the BLER threshold for OOS conditions by more than an offset value Z1%), the primary radio 120 of the wireless device 102 may switch from the relaxed mode 602 to the normal (non-relaxed, non-extended) mode 604. Alternatively and / or additionally, when the SINR measurement result meets the SINR threshold for OOS conditions (or falls below the SINR threshold for OOS conditions by an offset value Y1%), the primary radio 120 of the wireless device 102 may switch from the relaxed mode 602 to the normal (non-relaxed, non-extended) mode 604. In some embodiments, the primary radio 120 of the wireless device 102 may switch from the normal mode 604 to the relaxed mode 602 when the BLER measurement result meets the BLER threshold for in-sync conditions (or falls below the BLER threshold for in-sync conditions by an offset value Z2%). Alternatively and / or additionally, in some embodiments, the primary radio 120 of the wireless device 102 may switch from the normal mode 604 to the relaxed mode 602 when the SINR measurement result meets the SINR threshold for the synchronization condition (or exceeds the SINR threshold for the OOS condition by more than an offset value Y2%).

[0042] In some embodiments, when the primary radio 120 of the wireless device 102 is in a sleep state and the OOS condition is not satisfied based on RLM using the LP-WUS burst 252, the wireless device 102 performs radio link monitoring (RLM) using the LP-WUR 122 by processing the LP-WUS 108 repetitions of the LP-WUS burst 252. In some embodiments, when the OOS condition is satisfied based on RLM using the LP-WUS burst 252 (including when the LP-WUS burst indicates that the primary radio 120 should be in a sleep state), the wireless device 102 wakes the primary radio 120 from the sleep state and performs RLM using the legacy reference signal 110. In some embodiments, RLM using the legacy reference signal 110 may be performed using a relaxed (time-extended) schedule after waking up the primary radio 120 when the OOS condition is satisfied based on the LP-WUS RLM measurement results. In some embodiments, RLM using the legacy reference signal 110 may be performed using normal (non-time-stretched) scheduling when an OOS condition is met based on legacy reference RLM measurements and / or when the primary radio 120 is woken up based on a wakeup indication received in the LP-WUS burst 252 .

[0043] Figure 6BA diagram 650 is shown of an exemplary mapping of evaluation results (e.g., BLER values) to different synchronization conditions and operating modes. When the primary radio 120 is in a sleep state, the wireless device 102 can perform RLM using the LP-WUR 122 and determine whether the wireless device 102 is in synchronization or out of synchronization (OOS) based on the measurement results repeatedly performed by the LP-WUS 108 using the LP-WUS burst 252. The LP-WUR synchronization region 654 can be wider (contain more BLER values) than the corresponding primary radio synchronization region 652, for example, a wide additional BLER value Y%. Similarly, the LP-WUR OOS region 664 can be wider than the corresponding primary radio OOS region 662, for example, a wide additional BLER value X%. Using the LP-WUR 122, the wireless device 102 can determine the synchronization condition or OOS condition more quickly when the BLER value changes. When an OOS condition is determined using the LP-WUR 122, the wireless device 102 may wake up the primary radio 120 and perform RLM using the primary radio 120 based on measurements of the legacy reference signal 110. Initially, upon crossing into the OOS region 664, the wireless device 102 may configure the primary radio 120 to perform RLM using the relaxed mode 602 schedule. When the BLER determined using the legacy reference signal processed by the primary radio 120 crosses a boundary below the OOS region 662 of the primary radio 120 (e.g., is wider by an additional Z%), the primary radio 120 may transition from performing RLM using the relaxed mode 602 schedule to performing RLM using the normal non-relaxed mode 604 schedule. Between the synchronization region and the OOS region, the wireless device 102 operates in the hysteresis region 660, maintaining the previously determined (and current) synchronization / OOS condition until the BLER threshold for the change determination is met. Figure 6B A BLER example is shown, and a similar partitioning based on SINR values ​​may be used instead of or in addition to the wireless device 102 using BLER values ​​for synchronization / OOS determination.

[0044] Figure 7A flowchart 700 of an exemplary method for radio link monitoring (RLM) performed by a wireless device 102 is shown. At 702, the wireless device 102 transitions a low power wake-up radio (LP-WUR) 122 from a sleep state to an awake state. At 704, the wireless device 102 receives, via the LP-WUR 122, N repetitions of a low power wake-up signal (LP-WUS) burst 252 including the LP-WUS 108. At 706, the wireless device 102 determines that the LP-WUS burst 252 indicates to keep the primary radio 120 of the wireless device 102 in sleep. At 708, the wireless device 102 processes the LP-WUS burst 252 to generate one or more RLM evaluation results (measurements for performance evaluation). At 710, the wireless device 102 compares the one or more RLM evaluation results with corresponding thresholds. At 712, when at least one of the one or more RLM evaluation results satisfies a corresponding threshold, the wireless device 102 i) wakes up a primary radio 120 of the wireless device 102 from a sleep state, ii) indicates to the cellular wireless network that the state of the primary radio 120 has changed from the sleep state to the awake state, and iii) performs RLM using an additional signal received via the primary radio 120.

[0045] In some embodiments, when the LP-WUS burst 252 indicates to wake up the primary radio 120, the wireless device 102 wakes up the primary radio 120 of the wireless device 102 to perform RLM using the primary radio 120. In some embodiments, each repetition of the LP-WUS 108 includes an information portion 404 and a synchronization portion 402; the wireless device 102 determines whether to wake up the primary radio 120 based on the information portion 404; and the wireless device 102 processes the synchronization portion 402 of the LP-WUS burst 252 to generate the one or more RLM evaluation results. In some embodiments, the information portion 404 includes an indication of a wake-up value or a sleep value of the primary radio, and the synchronization portion 402 includes a sequence for timing and frequency tracking. In some embodiments, processing the LP-WUS burst 252 to generate the one or more RLM evaluation results includes calculating an LP-WUS block error rate (BLER) value using M≤N consecutive repetitions of the LP-WUS 108 in the evaluation window 302. In some embodiments, comparing the one or more RLM evaluation results includes comparing the LP-WUSBLER value to an LP-WUSBLER threshold to determine an in-sync or out-of-sync (OOS) condition of the wireless device 102. In some embodiments, the LP-WUSBLER value satisfies the LP-WUSBLER threshold and indicates an OOS condition when the LP-WUSBLER value exceeds the master radio BLER threshold plus a negative BLER offset value. In some embodiments, processing the LP-WUS burst 252 to generate the one or more RLM evaluation results also includes calculating N-M+1 LP-WUSBLER values ​​using M≤N consecutive repetitions of the LP-WUS 108 in a sliding evaluation window 302, the sliding evaluation window calculating a shift sliding step value for each LP-WUSBLER. In some embodiments, comparing the one or more RLM evaluation results also includes comparing each of the N-M+1 LP-WUS BLER values ​​to the LP-WUSBLER threshold to determine an in-sync or OOS condition. In some embodiments, comparing the one or more RLM evaluation results further comprises comparing an average of the N-M+1 LP-WUSBLER values ​​to a LP-WUSBLER threshold to determine an in-sync or out-of-sync condition. In some embodiments, processing the LP-WUS burst 252 to generate the one or more RLM evaluation results comprises calculating an LP-WUS signal to interference plus noise ratio (SINR) value using M≤N consecutive repetitions of the LP-WUS 108 in the evaluation window 302. In some embodiments, comparing the one or more RLM evaluation results comprises comparing the LP-WUS SINR value to a LP-WUS SINR threshold to determine an in-sync or out-of-sync (OOS) condition of the wireless device 102.In some embodiments, the LP-WUS SINR value satisfies the LP-WUS threshold and indicates a synchronization condition when the LP-WUS SINR value rises above the primary radio BLER threshold plus the positive SINR offset value. In some embodiments, performing RLM using an additional signal received via the primary radio 120 includes using the primary radio 120 to determine whether the wireless device 102 meets the synchronization or OOS condition based on the measurement and processing of a set of received traditional reference signals 110. In some embodiments, the traditional reference signal 110 includes one or more of the following: a synchronization symbol block (SSB) signal or a channel state information reference signal (CSI-RS). In some embodiments, the primary radio 120 performs RLM using an additional signal received via the primary radio 120 based on a relaxed schedule, wherein the relaxed schedule has an evaluation time period scaled by a positive factor K>1 relative to the normal RLM schedule of the primary radio 120. In some embodiments, wireless device 102 switches RLM using primary radio 120 from relaxed scheduling to normal RLM scheduling when the results of performing RLM using additional signals received via primary radio 120 include a BLER exceeding the primary radio BLER threshold plus a positive BLER offset value.

[0046] Representative exemplary devices

[0047] Figure 8 An exemplary computing device 800 that can be used to implement various components and techniques described herein according to some embodiments is shown in a block diagram format. In particular, a detailed view of the exemplary computing device 800 illustrates various components that can be included in the wireless device 102. Figure 8As shown, the computing device 800 may include one or more processors 802 representing a microprocessor or controller for controlling the overall operation of the computing device 800. In some embodiments, the computing device 800 may also include a user input device 808 that allows a user of the computing device 800 to interact with the computing device 800. For example, in some embodiments, the user input device 808 may take a variety of forms, such as buttons, keypads, dials, touch screens, audio input interfaces, visual / image capture input interfaces, input in the form of sensor data, etc. In some embodiments, the computing device 800 may include a display 810 (screen display) that can be controlled by the processor 802 to display information (e.g., information related to incoming, outgoing, or active communication sessions) to the user. The data bus 816 can facilitate data transmission between at least the storage device 840, the processor 802, and the controller 813. The controller 813 can be used to interact with and control different equipment through the equipment control bus 814. The computing device 800 may also include a network / bus interface 811 coupled to the data link 812. In the case of a wireless connection, the network / bus interface 811 may include wireless circuitry, such as a wireless transceiver and / or a baseband processor. The computing device 800 may also include a secure element 824. The secure element 824 may include an eUICC.

[0048] The computing device 800 also includes a storage device 840, which may include a single storage device or multiple storage devices (e.g., a hard drive), and includes a storage management module that manages one or more partitions within the storage device 840. In some embodiments, the storage device 840 may include flash memory, semiconductor (solid-state) memory, etc. The computing device 800 may also include a random access memory (RAM) 820 and a read-only memory (ROM) 822. The ROM 822 may store programs, utilities, or processes to be executed in a non-volatile manner. The RAM 820 may provide volatile data storage and store instructions related to the operation of the computing device 800.

[0049] Wireless Terminology

[0050] According to various embodiments described herein, the terms "wireless communication device", "wireless device", "mobile device", "mobile station", and "user equipment (UE)" may be used interchangeably herein to describe one or more common consumer electronic devices that may be capable of performing the processes associated with various embodiments of the present disclosure. According to various specific implementations, any of these consumer electronic devices may relate to: a cellular phone or smart phone, a tablet computer, a laptop computer, a notebook computer, a personal computer, a netbook computer, a media player device, an e-book device, Devices, wearable computing devices, and any other type of electronic computing device with wireless communication capabilities, which wireless communication capabilities may include communication via one or more wireless communication protocols, such as protocols used to communicate on the following networks: wireless wide area networks (WWAN), wireless metropolitan area networks (WMAN), wireless local area networks (WLAN), wireless personal area networks (WPAN), near field communication (NFC), cellular wireless networks, fourth generation (4G) LTE, advanced LTE (LTE-A) 5G, and / or 5G advanced or other currently or future developed advanced cellular wireless networks.

[0051] In some embodiments, the wireless communication device may also operate as part of a wireless communication system, which may include a group of client devices, which may also be referred to as stations, client wireless devices, or client wireless communication devices, interconnected to an access point (AP) (e.g., as part of a WLAN), and / or interconnected to each other (e.g., as part of a WPAN and / or "ad hoc" wireless network). In some embodiments, the client device may be any wireless communication device capable of communicating via WLAN technology (e.g., according to a wireless local area network communication protocol). In some embodiments, the WLAN technology may include a Wi-Fi (or more generally, a WLAN) wireless communication subsystem or radio component, which may implement the Institute of Electrical and Electronics Engineers (IEEE) 802.11 technology, such as one or more of the following: IEEE 802.11a; IEEE 802.11b; IEEE 802.11g; IEEE 802.11-2007; IEEE 802.11n; IEEE 802.11-2012; IEEE 802.11ac; or other currently or future developed IEEE 802.11 technology.

[0052] In addition, it should be understood that the UE described herein may be configured as a multi-mode wireless communication device that is also capable of communicating via different third generation (3G) and / or second generation (2G) RATs. In these cases, the multi-mode user equipment (UE) may be configured to prefer attaching to an LTE network that provides a faster data rate throughput over other 3G legacy networks that provide a lower data rate throughput. For example, in some specific implementations, the multi-mode UE may be configured to fall back to a 3G legacy network, such as an evolved high speed packet access (HSPA+) network, or a code division multiple access (CDMA) 2000 evolution-data only (EV-DO) network when 5G, LTE, and LTE-A networks are otherwise unavailable.

[0053] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0054] The various aspects, embodiments, specific implementations or features of the embodiments may be used individually or in any combination. The various aspects of the embodiments may be implemented by software, hardware, or a combination of hardware and software. The embodiments may also be implemented as computer-readable code on a non-transient computer-readable medium. A non-transient computer-readable medium is any data storage device that can store data, which can then be read by a computer system. Examples of non-transient computer-readable media include read-only memory, random access memory, CD-ROM, HDD, DVD, magnetic tape, and optical data storage devices. Non-transient computer-readable media may also be distributed on a network-coupled computer system so that the computer-readable code is stored and executed in a distributed manner.

[0055] For the purpose of illustration, the foregoing description uses specific nomenclature to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that specific details are not required in order to practice the embodiments. Therefore, the foregoing description of specific embodiments is presented for the purpose of illustration and description. The foregoing description is not intended to be exhaustive or to limit the embodiments described to the precise form disclosed. It will be apparent to those of ordinary skill in the art that, in view of the above teachings, many modifications and variations are feasible.

Claims

1. A method for radio link monitoring (RLM) of a cellular wireless network, the method comprising: By wireless device: Transitioning a low power wake-up radio (LP-WUR) from a sleep state to a wake state; receiving, via the LP-WUR, a low power wake-up signal (LP-WUS) burst comprising N repetitions of a LP-WUS; determining that the LP-WUS burst indicates keeping a primary radio of the wireless device asleep; processing the LP-WUS burst to generate one or more RLM evaluation results; comparing the one or more RLM evaluation results to corresponding thresholds; as well as When at least one of the one or more RLM evaluation results meets a corresponding threshold: waking up the primary radio of the wireless device; indicating the awake state of the primary radio to the cellular wireless network; receiving an additional signal via the primary radio; as well as RLM is performed using the additional signal received via the primary radio.

2. The method according to claim 1, wherein: Each of the N repetitions of the LP-WUS burst comprises an information portion and a synchronization portion; determining to keep the primary radio in sleep is based on the information portion; and The synchronization portion of the LP-WUS burst is processed to produce the one or more RLM evaluation results.

3. The method according to claim 2, wherein: The information portion includes an indication of a wake-up value or a sleep value for the primary radio; and The synchronization part includes sequences for timing and frequency tracking.

4. The method according to claim 1, wherein: Processing the LP-WUS burst to generate the one or more RLM evaluation results includes calculating a LP-WUS block error rate (BLER) value using M≤N consecutive repetitions of the LP-WUS in an evaluation window; and comparing the one or more RLM evaluation results includes comparing the LP-WUSBLER value to an LP-WUSBLER threshold to determine an in-sync condition or an out-of-sync (OOS) condition of the wireless device, Wherein the LP-WUSBLER value satisfies the LP-WUSBLER threshold and the OOS condition is indicated when the LP-WUSBLER value exceeds a primary radio BLER threshold plus a negative BLER offset value.

5. The method of claim 4, wherein processing the LP-WUS burst to generate the one or more RLM evaluation results further comprises calculating N-M+1 LP-WUSBLER values ​​using M≤N consecutive repetitions of the LP-WUS in a sliding evaluation window, the sliding evaluation window calculating a shift sliding step value for each LP-WUSBLER.

6. The method of claim 5, wherein comparing the one or more RLM evaluation results further comprises comparing each of the N-M+1 LP-WUSBLER values ​​with the LP-WUSBLER threshold to determine the synchronization condition or the OOS condition.

7. The method of claim 5, wherein comparing the one or more RLM evaluation results further comprises comparing an average of the N-M+1 LP-WUSBLER values ​​with the LP-WUSBLER threshold to determine the synchronization condition or the OOS condition.

8. The method according to claim 1, wherein: Processing the LP-WUS burst to generate the one or more RLM evaluation results includes calculating a LP-WUS signal to interference plus noise ratio (SINR) value using M≤N consecutive repetitions of the LP-WUS in an evaluation window; and comparing the one or more RLM evaluation results includes comparing the LP-WUS SINR value to an LP-WUS SINR threshold to determine an in-sync condition or an out-of-sync (OOS) condition of the wireless device, Wherein the LP-WUS SINR value satisfies the LP-WUS SINR threshold and the synchronization condition is indicated when the LP-WUS SINR value rises above a primary radio SINR threshold plus a positive SINR offset value.

9. The method of claim 1 , wherein performing RLM using the additional signal received via the primary radio comprises determining, using the primary radio, whether the wireless device satisfies an in-sync condition or an out-of-sync (OOS) condition based on measurement and processing of a set of received legacy reference signals.

10. The method of claim 9, wherein the set of received legacy reference signals comprises one or more of: a synchronization symbol block (SSB) signal or a channel state information reference signal (CSI-RS).

11. The method of claim 9, wherein the primary radio performs RLM using the additional signal received via the primary radio based on a relaxed schedule, wherein the relaxed schedule has an evaluation time period scaled by a positive factor K>1 relative to a normal RLM schedule of the primary radio.

12. The method according to claim 11, further comprising: By the wireless device: When a result of performing the RLM using the additional signal received via the primary radio includes a BLER exceeding a primary radio BLER threshold plus a positive BLER offset value, switching RLM using the primary radio from the relaxed scheduling to the normal RLM scheduling.

13. An apparatus configurable for operation in a wireless device, the apparatus comprising one or more processors coupled to a memory storing instructions, the instructions, when executed by the one or more processors, configuring the wireless device to: Transitioning a low power wake-up radio (LP-WUR) from a sleep state to a wake state; receiving, via the LP-WUR, a low power wake-up signal (LP-WUS) burst comprising N repetitions of a LP-WUS; determining that the LP-WUS burst indicates keeping a primary radio of the wireless device asleep; processing the LP-WUS burst to generate one or more radio link monitoring (RLM) evaluation results; comparing the one or more RLM evaluation results to corresponding thresholds; as well as When at least one of the one or more RLM evaluation results meets a corresponding threshold: waking up the primary radio of the wireless device; indicating the awake state of the primary radio to a cellular wireless network; receiving an additional signal via the primary radio; as well as RLM is performed using the additional signal received via the primary radio.

14. The device according to claim 13, wherein: Each of the N repetitions of the LP-WUS includes an information portion and a synchronization portion; determining to keep the primary radio in sleep is based on the information portion; and The synchronization portion of the LP-WUS burst is processed to produce the one or more RLM evaluation results.

15. The device according to claim 14, wherein: The information portion includes an indication of a wake-up value or a sleep value for the primary radio; and The synchronization part includes sequences for timing and frequency tracking.

16. The apparatus of claim 13, wherein: The wireless device processes the LP-WUS burst to generate the one or more RLM evaluation results by at least: calculating an LP-WUS block error rate (BLER) value using M≤N consecutive repetitions of the LP-WUS in the LP-WUS burst in an evaluation window; and The wireless device compares the one or more RLM evaluation results by at least comparing the LP-WUSBLER value to an LP-WUSBLER threshold to determine an in-sync condition or an out-of-sync (OOS) condition of the wireless device, Wherein the LP-WUSBLER value satisfies the LP-WUSBLER threshold and the OOS condition is indicated when the LP-WUSBLER value exceeds a primary radio BLER threshold plus a negative BLER offset value.

17. The device according to claim 16, wherein: Processing the LP-WUS burst by the wireless device to generate the one or more RLM evaluation results also includes calculating N-M+1 LP-WUSBLER values ​​using M≤N consecutive repetitions of the LP-WUS signal in a sliding evaluation window, wherein the sliding evaluation window calculates a shift sliding step value for each LP-WUSBLER.

18. The device according to claim 17, wherein: The wireless device compares the one or more RLM evaluation results by at least comparing each of the N-M+1 LP-WUSBLER values ​​to the LP-WUSBLER threshold to determine the synchronization condition or the OOS condition.

19. The apparatus of claim 17, wherein: The wireless device compares the one or more RLM evaluation results by at least comparing an average of the N-M+1 LP-WUSBLER values ​​to the LP-WUSBLER threshold to determine the synchronization condition or the OOS condition.

20. The apparatus of claim 13, wherein: The wireless device processes the LP-WUS burst to generate the one or more RLM evaluation results by at least: calculating a LP-WUS signal to interference plus noise ratio (SINR) value using M≤N consecutive repetitions of the LP-WUS in an evaluation window; and The wireless device compares the one or more RLM evaluation results by at least comparing the LP-WUS SINR value to an LP-WUS SINR threshold to determine an in-sync condition or an out-of-sync (OOS) condition of the wireless device, Wherein the LP-WUS SINR value satisfies the LP-WUS SINR threshold and the synchronization condition is indicated when the LP-WUS SINR value rises above a primary radio SINR threshold plus a positive SINR offset value.

21. The apparatus of claim 13, wherein: The wireless device performs RLM using the additional signal received via the primary radio at least by determining, using the primary radio, whether the wireless device meets an in-sync condition or an out-of-sync (OOS) condition based on measurement and processing of a set of received legacy reference signals.

22. The apparatus of claim 21, wherein the set of received legacy reference signals comprises one or more of: a synchronization symbol block (SSB) signal or a channel state information reference signal (CSI-RS).

23. The apparatus of claim 21, wherein the primary radio performs RLM using the additional signal received via the primary radio based on a relaxed schedule, wherein the relaxed schedule has an evaluation time period scaled by a positive factor K>1 relative to a normal RLM schedule of the primary radio.

24. The apparatus of claim 23, wherein execution of the instructions further configures the wireless device to: When a result of performing the RLM using the additional signal received via the primary radio includes a BLER exceeding a primary radio BLER threshold plus a positive BLER offset threshold, switching RLM using the primary radio from the relaxed scheduling to the normal RLM scheduling.

25. A wireless device, comprising: a wireless circuit comprising a plurality of antennas; At least one processor communicatively coupled to the wireless circuitry and to a memory storing instructions that, when executed by the at least one processor, cause the wireless device to perform a method according to any one of claims 1 to 12.

26. A non-transitory computer readable medium storing instructions which, when executed by at least one processor of a wireless device, configure the wireless device to perform the method of any one of claims 1 to 12.

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