Low-power wake-up receiver for low-latency devices
By defining time schedules for main and low-power wake-up signal intervals, the method addresses power and latency challenges in mobile devices, enabling efficient energy use and reduced latency in communication.
Patent Information
- Application Number
- JP2024544806
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-01-28
- Filing Date
- 2023-01-20
- Publication Date
- 2025-01-30
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Mobile devices with limited energy resources face challenges in maintaining operation for extended periods while balancing power consumption and latency, particularly when using low-power wake-up receivers that can increase latency during discontinuous reception cycles.
Implementing a method that includes defining time schedules for both main signal and low-power wake-up signal intervals, allowing the device to operate in different power-saving modes based on the detection of wake-up signals, thereby reducing power consumption and latency through strategic communication timing.
This approach effectively balances power consumption and latency by allowing the device to communicate at predefined intervals, ensuring efficient energy use without compromising responsiveness.
Smart Images
Figure 2025503233000001_ABST
Abstract
Description
[Technical field]
[0001] Various examples relate to methods of operating a mobile device in a power saving mode. [Background technology]
[0002] Energy efficiency is a key design requirement for mobile devices (UEs) with limited energy resources, e.g., UEs using small rechargeable and single coin cell batteries. In some use cases, UEs may be equipped with sensors and / or actuators and may be deployed in large numbers for monitoring, measuring, charging, etc. In many of these cases, the UE batteries may not be rechargeable and are expected to last at least several years, as described in 3GPP TR 38.875 version 17.0. UEs may also include wearables, such as smart watches, rings, e-health related devices, and medical monitoring devices. Given typical battery capacities, it is difficult to sustain UE operation for up to 1-2 weeks, which is often required.
[0003] It is proposed to wake up the UE's receiver only periodically, for example once per predefined discontinuous reception (DRX) cycle. Periodic activation of the receiver may occupy the UE's power consumption during periods when there is no signaling or data traffic.
[0004] Using a low power wake-up receiver in the UE, e.g. a special ultra-low power wake-up receiver (LP-WuRX), and activating said receiver (hereinafter the main receiver) according to a DRX cycle only in response to detecting a wake-up signal by the low power wake-up receiver, can significantly reduce the energy consumption associated with channel listening / monitoring, especially if the low power wake-up receiver also operates based on a discontinuous reception cycle.
[0005] However, while the proposed power modes can reduce power consumption, they may result in increased latency, which may be unacceptable in some use cases, for example when the UE has to respond to an alarm triggered by detecting a fault that occurred during manufacturing (e.g. in the manufacturing process at a factory). Summary of the Invention [Problem to be solved by the invention]
[0006] Therefore, a method may be needed to support UEs that have both limited energy resources and an upper bound on required communication delay. [Means for solving the problem]
[0007] Said needs are addressed by the subject matter of the independent claims. Advantageous embodiments are set forth in the dependent claims.
[0008] An example is a method of operating a mobile device (UE) in a power saving mode, comprising the steps of: obtaining a first power saving mode configuration indicating a time schedule of a predefined main signal time interval and a time schedule of a predefined low power wakeup signal time interval, and a second power saving mode configuration associated with an always-on operation; and, upon the UE obtaining a trigger for operating in the first power saving mode, operating the UE in the first power saving mode, the step of operating in the first power saving mode including the steps of monitoring a low power wakeup signal according to the time schedule of the predefined low power wakeup signal time intervals; and, when the UE obtains a trigger to operate in the second power saving mode, operating the UE in the second power saving mode, the operating in the second power saving mode including: continuously monitoring for a low power wake-up signal; and, in response to detecting the low power wake-up signal, communicating a primary signal at a primary signal time interval of a predefined primary signal time interval that is dependent on a time of detecting the low power wake-up signal.
[0009] An example is a method of operating an access node (AN), comprising the steps of obtaining a first power saving mode configuration for a UE indicating a time schedule of predefined main signal time intervals and a time schedule of predefined low power wakeup signal time intervals, and a second power saving mode configuration associated with always-on operation, wherein operating the UE in the first power saving mode includes the steps of monitoring for a low power wakeup signal according to the time schedule of the predefined low power wakeup signal time intervals, and in response to detecting a low power wakeup signal in one of the predefined low power wakeup signal time intervals, monitoring for a low power wakeup signal according to the time schedule of the predefined low power wakeup signal time intervals. and communicating a primary signal at a primary signal time interval of a signal time interval, wherein operating the UE in a second power saving mode includes continuously monitoring for a low power wakeup signal and, in response to detecting the low power wakeup signal, communicating a primary signal at a primary signal time interval dependent on a time at which the low power wakeup signal is detected, and, upon evaluating the UE operating in the first power saving mode, transmitting a low power wakeup signal to the UE in accordance with the first power saving mode and, upon evaluating the UE operating in the second power saving mode, transmitting a low power wakeup signal to the UE in accordance with the second power saving mode.
[0010] A further example provides a UE comprising a control circuit, the control circuit configured to perform the above-mentioned method.
[0011] As a further example, an AN is provided that includes a control circuit, the control circuit configured to perform the method described above. [Brief description of the drawings]
[0012] [Figure 1] FIG. 1 shows a schematic diagram of communication in a communication network. [Diagram 2] FIG. 2 illustrates a schematic diagram of a UE and an AN. [Diagram 3] FIG. 3 illustrates the power modes. [Figure 4] FIG. 4 illustrates generally a method of operating a UE. [Diagram 5] FIG. 5 illustrates generally how an AN may be operated. [Figure 6] FIG. 6 shows a schematic diagram of the selection of the power saving mode. [Figure 7] FIG. 7 illustrates diagrammatically signaling in a communication network. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] FIG. 1 illustrates an exemplary communication network 1000 according to some embodiments. The communication network 1000 may include a cellular network. In particular, the communication network 1000 according to the example of FIG. 1 may implement a 3GPP LTE architecture, sometimes referred to as an evolved packet system (EPS). The communication network 1000 may also implement a 5G core network (5GC). In the following, a scenario is described in the context of a radio link 1100 between a UE 1100 and an access node 1100 of the communication network 1000 operating according to a 3GPP NR radio access technology (RAT) or a 3GPP LTE RAT, in particular an LTE MTC. Similar techniques can be readily applied to various types of 3GPP-specified RATs, such as Global System for Mobile Communications (GSM), Wideband Code Division Multiplexing (WCDMA), General Packet Radio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE), Enhanced GPRS (EGPRS), Universal Mobile Telecommunications System (UMTS), and High Speed Packet Access (HSPA), as well as corresponding architectures of related cellular networks. Similar techniques can also be applied to 5G New Radio (NR) and NR-IoT.
[0014] A further specific example is the 3GPP NB-IoT RAT, which may be based on the 3GPP LTE RAT, i.e., Evolved UMTS Terrestrial Radio Access (E-UTRA). Furthermore, the NB-IoT RAT may be combined with EPS, as shown in Figure 1. The examples disclosed herein may alternatively or additionally be used for the 3GPP NB-IoT RAT.
[0015] Other examples include other types of networks, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11X wireless local area network, Bluetooth®, or Zigbee®.
[0016] The UE 1100 is connected to an access node (AN) 1100 of the communication network 1000 via a wireless link 1500. In one example, the UE 1100 and the AN 1200 may implement an evolved UMTS terrestrial radio access technology (E-UTRAN) or a 5G technology standard. Thus, the AN 1200 may implement, among other things, an evolved Node B (eNB) or a next generation Node B (gNB).
[0017] In the example, the UE 1100 is selected from a group including a smartphone, a mobile phone, a table, a notebook, a computer, a smart TV, an MTC device, an IoT device, an eMTC, a RedCap device, and the like.
[0018] MTC, eMTC, RedCap, or IoT devices are typically devices with low to medium requirements for data traffic volume. Furthermore, communications using these devices must achieve low complexity and low cost. Furthermore, to allow battery-powered devices to continue functioning for a relatively long time, the energy consumption of the MTC, eMTC, RedCap, or IoT devices must be relatively low, i.e., the battery life must be sufficiently long. For example, the IoT device may be connected to the EPS (or 5GC) via the NB-IoT RAT.
[0019] Communication over wireless link 1500 may be in the uplink (UL) and / or downlink (DL) direction.
[0020] 2 shows further details of the AN 2200 and the UE 2100 communicating over a wireless link 2500. The AN 2200 comprises a control circuit 2210 for operating the AN 2200, in particular according to the methods described below. The control circuit 2210 may comprise a processor 2211 and a memory 2212. The AN 2200 further comprises a transceiver 2220 configured to receive and / or transmit signals over the wireless link 2500. Similarly, the UE 2100 comprises a control circuit 2110 for operating the UE 2100, in particular according to the methods described below. The control circuit 2110 may comprise a processor 2111 and a memory 2112. The UE 2100 comprises a primary transceiver 2121 and a low power wake-up receiver 2122. The primary transceiver 2121 may be configured to receive and / or transmit many types of signals that may be communicated over the wireless link 2500 in accordance with the standards implemented by the communication network. The low power wake-up receiver 2122 may consume less power at startup compared to the primary transceiver 2121. The low power wake-up receiver 2122 may only be capable of detecting and / or receiving signals on the wireless link 2500. The low power wake-up receiver 2122 may not be able to transmit signals on the wireless link 2500. In particular, the low power wake-up receiver 2122 may only be capable of detecting and / or receiving low power wake-up signals. The low power wake-up receiver 2122 may not be able to receive the primary signal. The primary transceiver 2121 and the low power wake-up receiver may share the same antenna and / or RF front-end.
[0021] FIG. 3 shows examples of power modes 3100, 3200, 3300, 3400, 3500 in which a UE may operate.
[0022] Operation in power modes 3400, 3500 may include using a low power receiver in addition to a primary receiver, particularly in addition to a primary transceiver. Power modes 3100, 3200, 3300 may also be used by UEs equipped with only a primary transceiver, particularly only a primary receiver.
[0023] The primary receiver may always be activated in power mode 3100. Thus, the UE may always communicate a primary signal with the primary receiver, as indicated by the diagonal line from the lower left to the upper right. If data is available for communication at time 3001, the UE may immediately begin communicating the primary signal using the primary receiver.
[0024] The power mode 3200 may be defined to activate the primary receiver according to a time schedule of predefined primary signal time intervals 3211, 3212, 3213. Predefinition may include that the time and / or length of the primary signal time intervals 3211, 3212, 3213 are known to the UE before the UE actually operates in the power mode 3200. In some examples, the schedule of the predefined primary signal time intervals 3211, 3212, 3213 defines a periodic distribution of the primary signal time intervals 3211, 3212, 3213. Thus, the UE may communicate (i.e., receive and / or transmit) the primary signal only in the primary signal time intervals 3211, 3212, 3213. The length of the primary signal time interval may correspond to a duration of DRX. Compared to the power mode 3100, the power consumption of the power mode 3200 may be less. Thus, the power mode 3200 may be considered a power safe mode. However, if data is available for communication at time 3001, the UE must wait until the primary signal time interval 3212 before the primary signal can be communicated. Thus, power safe mode 3200 may mean high latency.
[0025] In the power mode 3300, the primary receiver can operate in a sleep mode and an active mode. The power mode 3300 can be defined to operate the primary receiver in a sleep mode according to a time schedule of predefined wake-up signal time intervals 3321, 3322, 3323. In response to detecting a wake-up signal 3303 in the wake-up signal time interval 3322, the UE can activate the primary receiver according to a primary signal time interval 3312 in which the UE communicates a primary signal.
[0026] The power mode 3300 may define a predefined time schedule for the primary signal time intervals 3311, 3312, 3313. The predefined time schedule for the wake-up signal time intervals 3321, 3322, 3323 may be defined relative to the predefined time schedule for the primary signal time intervals 3311, 3312, 3313. For example, it may be defined that the wake-up signal time interval 3322 ends at a time 3302 that is x time units (e.g., time slots, time frames, milliseconds) before the time 3304 at which the primary signal time interval 3312 begins. As shown by the different heights of the predefined wake-up signal time intervals 3321, 3322, 3323 and the predefined primary signal time intervals 3311, 3312, 3313, the power consumption of the primary receiver operating in a sleep mode may be lower than the power consumption of the primary receiver operating in an active mode.
[0027] The UE may communicate a primary signal in a primary signal time interval 3312 of the predefined primary signal time intervals 3311, 3312, 3313 in response to detecting the wake-up signal 3303 in the predefined wake-up signal time interval 3312. In particular, the UE may communicate a primary signal in a primary signal time interval 3312 of the predefined primary signal time intervals 3311, 3312, 3313 in response to a predefined wake-up signal time interval 3322 of one of the predefined wake-up signal time intervals 3321, 3322, 3323 in which the wake-up signal 3303 is detected. For example, the UE may communicate a primary signal in a primary signal time interval 3312 that is the primary signal time interval 3312 of the predefined primary signal time intervals 3311, 3312, 3313 that immediately follows the wake-up signal time interval 3322 in which the wake-up signal 3303 is detected. Therefore, the start 3304 of the predefined primary signal time interval 3312 is independent of the time 3303 of detecting the wake-up signal 3303. It is the wake-up signal time interval 3322 at which the wake-up signal 3303 is detected that determines which primary signal time interval 3312 to use. The positions of the primary signal time intervals 3311, 3312, 3313 are predefined.
[0028] Some aspects of power mode 3400 may be similar to power mode 3300. As previously mentioned, operation in power mode 3400 may include using a low power receiver in addition to a primary receiver / transceiver. A diagonal line from the upper left to the lower right may indicate an active low power receiver.
[0029] The power mode 3400 may define a predefined time schedule for the main signal time intervals 3411, 3412, 3413. A predefined time schedule for the low power wake-up signal time intervals 3421, 3422, 3423 may be defined in relation to the predefined time schedule for the main signal time intervals 3411, 3412, 3413. In the predefined time schedule for the low power wake-up signal time intervals, the UE is expected to listen for a potential low power wake-up signal. In particular, the low power wake-up signal time intervals may correspond to intervals during which the network may wake up the UE. The predefinition may include that the time points and / or lengths of the low power wake-up signal time intervals 3421, 3422, 3423 are known to the UE before the UE actually operates in the power mode 3400. For example, it may be specified that the low power wakeup signal time interval 3421 ends at time 3402 x time units (e.g., time slots, time frames, milliseconds) before the time 3404 when the main signal time interval 3412 begins. The time difference Δ3431 in power mode 3400 may be longer than the corresponding time difference Δ3331 in power mode 3300 to account for the longer time required to power up a stopped main receiver compared to a main receiver operating in sleep mode.
[0030] The power consumption of the low power receiver may be significantly lower than the power consumption of the primary receiver, as shown by the different heights of the predefined low power wakeup signal time intervals 3421, 3422, 3423 and the predefined primary signal time intervals 3411, 3412, 3413. In particular, the power consumption of the low power receiver may be even lower than the power consumption of the primary receiver operating in a sleep mode.
[0031] The UE may monitor the low power wakeup signal by the low power receiver according to a time schedule of predefined low power wakeup signal time intervals 3421, 3422, 3423. The UE may communicate a primary signal in a primary signal time interval 3412 of the predefined primary signal time intervals 3411, 3412, 3413 in response to detection of the low power wakeup signal 3403 in the predefined low power wakeup signal time interval 3422. In particular, the UE may communicate a primary signal in a primary signal time interval 3412 of the predefined primary signal time intervals 3411, 3412, 3413 in response to one of the predefined low power wakeup signal time intervals 3422 in which the low power wakeup signal 3403 is detected. For example, the UE may communicate a primary signal in a primary signal time interval 3412 that is the primary signal time interval 3412 of the predefined primary signal time intervals 3411, 3412, 3413 that immediately follows the low power wakeup signal time interval 3422 in which the low power wakeup signal 3403 is detected. Thus, the start 3404 of the predefined primary signal time interval 3412 is independent of the time 3403 of detecting the low power wakeup signal 3403. It is the low power wakeup signal time interval 3422 in which the wakeup signal 3403 is detected that determines which primary signal time interval 3412 to use. The temporal locations of the primary signal time intervals 3411, 3412, 3413 are predefined.
[0032] The low-power receiver may have reduced capabilities compared to the main receiver / transceiver. Therefore, the type of the low-power wake-up signal may not be complicated compared to the type of the main signal. For example, the low-power wake-up signal may require a simpler modulation and coding scheme. For example, the low-power wake-up signal is designed using On-Off Keying (OOK), Binary Phase Shift Keying (BFSK), Binary Phase Shift Keying BPSK modulation. For example, the low-power wake-up signal is a PN sequence or m sequence signal. The main signal may not be detectable and / or receivable and / or decodable by the low-power wake-up receiver. The low-power wake-up receiver can only receive signals, especially low-power wake-up signals. In particular, the low-power wake-up receiver may not be able to transmit signals.
[0033] According to the power modes 3200, 3300, 3400, the main signal may be communicated only in the predefined main signal time intervals 3211, 3212, 3213, 3311, 3312, 3313, 3411, 3412, 3413. Thus, if data is available for communication at time point 3001, it may take some time before the data can actually be transmitted in the respective next predefined main signal time interval 3212, 3312, 3412. In some use cases, such a delay is not acceptable. Thus, a method may be required that allows balancing power consumption and latency.
[0034] According to the power mode 3500, the UE continuously monitors for a low power wake-up signal 3503. In particular, the low power wake-up receiver may be activated at all times 3521. In an example, the maximum duration for which the UE continuously monitors for the low power wake-up signal may be set, for example, by the AN. In response to detecting the low power wake-up signal 3403, the UE may communicate a primary signal in a primary signal time interval 3512 that depends on the time of detection of the low power wake-up signal 3503. In particular, the start 3504 of the primary signal time interval 3512 may depend on the time of detecting the low power wake-up signal 3503. More broadly, the position in time of the primary signal time interval 3512 may depend on the time of detecting the low power wake-up signal 3503. The primary signal time interval 3512 is not predefined.
[0035] FIG. 4, in combination with FIG. 3, illustrates a method of operating a UE in a power saving mode. In 4010, the UE obtains a first power saving mode configuration indicating a time schedule of predefined main signal time intervals 3411, 3412, 3413 and a time schedule of predefined low power wake-up signal time intervals 3421, 3422, 3423, and a second power saving mode configuration associated with an always-on operation. In some examples, the UE can obtain the first power saving mode configuration by receiving a message from the AN regarding the first power saving mode configuration. In other examples, the UE can obtain the first power saving mode configuration by evaluating one or more criteria. The always-on operation can mean that the low power wake-up receiver is always active, thereby continuously or persistently monitoring for potential wake-up signals. The always-on operation can mean that the UE can always monitor for potential low power wake-up signals. In particular, the detection of the low power wake-up signal is not limited to the predefined low power wake-up signal time intervals.
[0036] Upon obtaining 4020 the trigger, the UE operates in the first power saving mode 3400, 4030. In some examples, the trigger may be related to a message or signal received or detected by the UE (i.e., a trigger message or trigger signal received from the AN). In some examples, the trigger may be the result of an evaluation performed by the UE (e.g., an evaluation that the UE is low on energy and therefore operates in the first power saving mode 3400). The trigger may be the result of at least one predefined rule or requirement. Operating the UE in the first power saving mode 3400 at 4030 includes monitoring for a low power wakeup signal 3403 at 4031 according to a time schedule of predefined low power wakeup signal time intervals 3421, 3422, 3423, and in response to detecting the low power wakeup signal 3403 in one of the predefined low power wakeup signal time intervals 3422, communicating a primary signal in a primary signal time interval 3412 of predefined primary signal time intervals 3412, 3412, 3413 at 4032.
[0037] Upon obtaining 4040 the trigger, 4050 the UE operates in the second power saving mode 3500. In some examples, the trigger may be related to a message or signal received or detected by the UE (i.e., a trigger message or trigger signal received from the AN). In some examples, the trigger may be the result of an evaluation performed by the UE (e.g., an evaluation that a user wearing the UE is exercising and important health related values may need to be transmitted with low latency and therefore it is preferable to operate the UE in the second power saving mode 3500). The trigger may be the result of a predefined rule or requirement. Operating the UE in the second power saving mode 3500 in 4050 includes continuously monitoring 4051 for a low power wake-up signal 3503 and, in response to detecting the low power wake-up signal 3503, communicating 4052 a primary signal in a primary signal time interval 3512 that depends on the time of detecting the low power wake-up signal 3503.
[0038] Thus, the method according to Fig. 4 allows to balance power consumption and latency. In particular, the first power saving mode 3400 may be advantageous in terms of power consumption, since the low power wake-up receiver only needs to be activated during the low power wake-up signal time interval. The second power saving mode 3500 may result in reduced latency, since the low power wake-up signal may be transmitted at any time. Furthermore, the main signal time interval is not predefined in the power saving mode 3500, so that the main signal time interval can start closer to the time of detecting the low power wake-up signal.
[0039] Figure 5, in combination with Figure 3, illustrates a method of operating an AN. At 5010, the AN obtains a first power save mode configuration for a UE, the first power save mode configuration indicating a time schedule of predefined main signal time intervals 3411, 3412, 3413 and a time schedule of predefined low power wake-up signal time intervals 3421, 3422, 3423, and a second power save mode configuration associated with always-on operation.
[0040] Operating the UE in the first power saving mode 3400 includes monitoring 4031 for a low power wakeup signal 3403 according to a time schedule of predefined low power wakeup signal time intervals 3421, 3422, 3423, and in response to detecting the low power wakeup signal 3403 in one of the predefined low power wakeup signal time intervals 3422, communicating 4032 a primary signal in a primary signal time interval 3412 of predefined primary signal time intervals 3412, 3412, 3413. Operating the UE in the second power saving mode 3500 at 4050 includes continuously monitoring 4051 for a low power wakeup signal 3503, and in response to detecting the low power wakeup signal 3503, communicating 4052 a primary signal in a primary signal time interval 3512 that depends on the time of detecting the low power wakeup signal 3503.
[0041] Upon evaluating 5020 that the UE is operating in the first power saving mode 3400, the AN transmits 5031 a low power wake-up signal to the UE according to the first power saving mode 3400. For example, if the UE needs to be woken up, the AN transmits 5031 a low power wake-up signal. Optionally, the AN can communicate a primary signal to the UE in one of the predefined primary signal time intervals 3412 in 5032. The evaluation in 5020 may refer to the AN knowing that the UE is operating in the first power saving mode 3400. Typically, both the AN and the UE need to know which power mode safety mode is being used. The UE needs said information to activate a low power wake-up receiver at the right time so that it can detect the expected low power wake-up signal, and the AN needs said information to transmit a wake-up signal at the right time, i.e., at the time when the UE monitors for the expected low power wake-up signal. Evaluating may refer to finding that the UE operates in the first power saving mode 3400. Evaluating may refer to receiving an explicit message, particularly from the UE, indicating that the UE operates in the first power saving mode. However, it may also refer to indirect information. For example, the AN may know that the UE has a certain capability, e.g., the capability to operate according to the first power saving mode, and that the UE is known to have relaxed latency requirements at the time. The AN may then evaluate that the UE is operating in the first power saving mode, since this is the most favorable power mode at the moment.
[0042] Upon evaluating 5040 that the UE is operating in the second power saving mode 3500, the AN transmits 5051 a low power wake-up signal to the UE in accordance with the second power saving mode 3500. Optionally, the AN may communicate a primary signal to the UE in 5052 in a primary signal time interval 3512 that is dependent on the time at which the AN transmits the low power wake-up signal 3503.
[0043] The advantages of the method of operating an AN according to FIG. 5 correspond to the advantages of the method of operating a UE according to FIG.
[0044] The power saving mode to be used by the UE may be determined according to different methods. Some specification cases may specify an upper limit on the communication delay, i.e., the time between when data to be transmitted to the UE is available at an Access Node (AN) and the possibility of transmitting a corresponding primary signal from the AN to the UE so that the UE can receive it. For example, with reference to FIG. 3, there may be an upper limit on the communication delay between the time 3001 when data to be transmitted to the UE is available and the primary signal time interval 3412, 3512 during which the UE can receive the primary signal. The upper limit on the communication delay may be defined as t req-d Moreover, a certain time may be required to wake up the primary receiver in response to detecting the low-power wake-up signal. The time may be the transition time t t Additionally, the predefined major time intervals may be provided according to a periodic schedule having a cycle time T. The cycle time T may correspond to the time difference Δ3230 shown in FIG.
[0045] 6 shows a procedure that may be used by a UE or an AN to evaluate a power mode to be used by the UE. At 6010, the following formula is evaluated: t t >t req-d
[0046] t req-d and t If the formula is correct given the current value of , i.e., there is not enough time to wake up the primary receiver, then at 6020 a power mode is selected that provides for the primary receiver to operate continuously.
[0047] If the expression evaluated in 6010 is incorrect, then the following expression is evaluated in 6030: t t <t req-d <T+t t
[0048] t t , t req-d , if this formula is true given the current value of T, then the second power saving mode may be selected at 6040. Alternatively, a first power saving mode setting that results in a different value of T may be selected, and the formula may be re-evaluated with the new value of T.
[0049] t t <t req-d <T+t t In the case of the formula, t req-d Given the current value of T is incorrect, the 6050 may select the second power saving mode.
[0050] The procedure for evaluating power modes described with respect to FIG. 6 may be performed by the UE and / or the AN.
[0051] As described above with respect to FIG. 5, the UE communicates at least one primary signal upon detecting the low power wake-up signal. The type and / or direction of the primary signal communicated may depend on the type of the detected low power wake-up signal, in particular the information carried in the low power wake-up signal. For example, communicating the primary signal may include receiving a downlink (DL) control and / or downlink data transmission, such as receiving a paging or normal DL message. In a further example, communicating the primary signal may include performing an uplink (UL) transmission, such as performing an early data transmission (EDT) as specified in 36.321 version 16.6.0, and / or a small data transmission (SDT), and / or a minimized drive test (MDT) as specified in 3GPP TS 37.320 version 16.7.0. In yet another example, communicating the primary signal may include initiating a random access procedure. For example, communicating the primary signal may include initiating a RACH procedure starting with a preamble transmission on the PRACH as specified in 3GPP TS 38.211 version 17.0.0. In other words, the information in the low power wake-up signal may indicate a subsequent operation.
[0052] The low power wake-up signal may be used for DL purposes, and the subsequent action after detection of the low power wake-up signal may be DL data reception, which may require a PDCCH transmission before DL data reception (PDSCH) or may require direct reception of DL data reception (PDSCH) on pre-configured resources.
[0053] The AN may transmit the corresponding DL data after a certain time offset t_offset relative to the time of transmitting the low power wake-up signal. Therefore, the communication of the main signal by the AN with the UE may depend on the time of transmitting the low power wake-up signal. offset is the transition time t t or more, which is necessary for the UE to activate its primary receiver and perform synchronization.
[0054] Time offset t offset may be a preset value. In an example, the first power saving mode setting and / or the second power saving mode setting may be a time offset t offset The time offset t offset may be selected depending on UE capabilities and / or channel conditions. For example, the power-on time and preparation time for DL reception may vary depending on whether all parts of the primary receiver are powered off or not. offset may correspond to the time difference Δ3532 shown in FIG.
[0055] Time offset t offset After that, the UE may configure its primary receiver for a period of time t to receive DL data (e.g., in the form of a DL control channel) and / or a configuration for receiving DL data. on The on-duration time t on may be a preset value. In the example, the first power saving mode setting and / or the second power saving mode setting may be set to an on duration t onThe on-duration in the second power saving mode t on may have the same value as the duration of the predefined low power wake-up time interval in the first power saving mode. For example, with respect to FIG. 3, the on-duration of the primary signal time interval 3512 may have the same value as the on-duration of the primary signal time interval 3412. In particular, the on-duration t on may have the same duration / value as the on duration of normal DRX or C-DRX configuration.
[0056] In this example, the on duration t on may be configured such that the UE can activate its primary receiver to receive settings for receiving DL data, turn off its primary receiver, and reactivate its receiver to receive DL data, which may allow further reduction in power consumption and / or further increase the likelihood that the AN and / or communication network can schedule its DL transmission.
[0057] As described above, when the UE detects the low power wake-up signal, the UE can transmit a main signal to the AN. The AN transmits the low power wake-up signal to the UE corresponding to the time when the AN detects the low power wake-up signal, and then transmits the main signal to the UE for a certain period of time t UL offset Depending on the expected UL activity, i.e., whether the AN expects to receive an SDT, an EDT, or a PRACH, the resources allocated or reserved for UL transmissions may be different (e.g., if PUR is used or if a preamble is transmitted over the PRACH).
[0058] The expected UL or DL activity after detection of the low power wake-up signal may depend on the content of the low power wake-up signal, i.e., it may be indicated in the low power wake-up signal, or the expected UL or DL activity may be indicated by a higher layer.
[0059] Obtaining the second power saving mode configuration and / or triggering the operation of the UE in the second power saving mode may be performed in different ways depending on the application and use case. For applications or use cases with strict communication delay limits, such as an alarm caused by a fault occurring during the manufacture of a product, the second power saving mode configuration may be provided to the UE when registering the UE with the communication network. When registering the UE with the communication network, the UE may also receive a message that triggers the UE to operate in the second power saving mode. A core network of the communication network may inform one or more of the ANs of the communication network, in particular the Radio Access Nodes (RANs), about the UE capabilities.
[0060] For applications such as a wearable device that may be used both to measure vital signs (e.g., heart rate) and for other activities, such as receiving text messages, obtaining the second power saving mode configuration and / or triggering operation of the UE in the second power saving mode may include radio resource control (RRC).
[0061] Triggering and / or canceling operation of the UE in the second power saving mode may be initiated by an AN of the communication network and / or the UE itself. Ceasing operation of the UE in the second power saving mode may include triggering the UE to operate in the first power saving mode. As previously mentioned, operating the UE in the first power saving mode may include operating the UE according to a legacy discontinuous reception (DRX) mode.
[0062] In some examples, the AN may cease operation of the UE in the second power mode by transmitting a specific type of low power wake-up signal that includes specific information specifically dedicated to this purpose. The low power wake-up signal may be detected by a low power wake-up receiver of the UE. In a further example, ceasing operation of the UE in the second power mode may include transmitting a primary signal from the AN to the UE that may be received at a primary transceiver of the UE. For example, information regarding the ceasing of operation of the UE in the second power mode may be included in a downlink control indicator (DCI) provided to the UE via at least one primary signal. In some examples, the AN may cease operation of the UE in the second power mode after a certain period of time during which the UE does not receive a signal, including a low power wake-up signal, from the AN. The UE may switch to the first power mode.
[0063] A control circuit connected to both the main transceiver and the low power wake-up receiver can trigger the UE to cease operation in the second power mode. The on or off switching action in the second power saving mode can be used for use cases where a short communication delay is required, for example when a manufacturing machine is operating or a person is exercising and wants to know exactly if the heart rate exceeds a threshold, and on the other hand, a longer communication delay can be allowed, for example when a manufacturing machine is at rest or a person is stationary. The on or off action of the trigger switch of the second power saving mode can be set by the application.
[0064] In some scenarios, the UE may cease operation in the second power saving mode when its stored energy falls below a certain level or when significant / short delays can be mitigated for a certain period of time. The UE may transmit a primary signal, e.g., SDT or EDT, to the AN to make the AN and / or core network aware that the UE has ceased operation in the second power saving mode.
[0065] 7 illustrates a schematic of signaling in a communication network according to an example of operating a UE in a power saving mode. The signaling does not necessarily occur in the example order shown in FIG.
[0066] When the UE is connected to a communication network, the UE may provide a message 7101 indicating the non-radio capabilities of the UE to the communication network (NW), in particular to the AMF (Access and Mobility Management Function) or Mobility Management Entity (MME) of 5GC. The message 7101 may be provided to the AMF or MME using a non-access stratum (NAS) protocol. Alternatively or in addition, the UE may provide a message 7102 indicating the non-radio capabilities of the UE to the serving AN. In an example, RRC signaling may be used to provide the message 7101 to the serving AN.
[0067] For example, if the UE has an essentially static configuration (e.g., sensors, fire alarm sensors) and relatively stringent delay requirements, message 7101 may typically be provided to the MME. In scenarios where the UE has a dynamic or semi-static configuration (e.g., wearables), message 7102 may typically be provided to the serving AN.
[0068] If the NW is aware of the UE's non-radio capabilities, the NW may provide a message 7103 to the serving AN indicating the UE's capabilities.
[0069] At 7201, the NW may store a UE context including information regarding the UE's capabilities non-radio capabilities.
[0070] Additionally, the UE may provide a message 7104 to the serving AN indicating the radio capabilities of the UE. For example, the message 7104 may indicate that the UE is equipped with a low power wake-up receiver. Optionally, the message 7104 may also indicate the transition time t 1 that the UE requires to activate its primary transceiver in response to detecting the low power wake-up signal. t It can be shown that
[0071] The AN may provide a message 7105 to the UE indicating a second power saving mode configuration. The message 7105 may indicate an AN supporting operation in the second power saving mode. The message 7105 may indicate further parameters related to operation in the second power saving mode. For example, the message 7105 may indicate one or more types of low power wake-up signals that the UE may be expected to detect. For example, the message 7105 may indicate time-frequency resources of encoding of information included in the low power wake-up signal, where the low power wake-up signal is detected.
[0072] Message 7105 may be provided using a broadcast signal. Message 7105 may be provided in system information. In some examples, message 7105 may be provided before message 7101 and / or message 7102 are exchanged.
[0073] Additionally, while operating in idle mode and / or connected mode, the UE may optionally provide a message 7106 indicating assistance information to the AN. The message 7106 may indicate a preferred first power saving mode configuration (e.g., a preferred cycle time of the periodic predefined low power wakeup signal time interval and / or the periodic predefined main signal time interval, and / or a delay tolerance).
[0074] At 7202, the AN may obtain a first power saving mode setting and / or a second power saving mode setting based on predetermined criteria, in particular based on a required communication delay upper limit, and optionally based on capability information and / or support information.
[0075] The UE may obtain a message 7107 from the serving AN indicating the obtained first power saving mode setting and / or second power saving mode operation. In an example, the message 7107 may be provided to the UE using RRC signaling. However, it may also be possible for the UE to independently determine the first power saving mode setting and / or the second power saving mode setting based on capability information and / or assistance information provided by the UE to the AN. The UE and the AN may independently determine the first power saving mode setting and / or the second power saving mode setting from each other, but may use the same decision criteria, so that the first power saving mode setting and / or the second power saving mode setting determined by the UE and the AN are the same.
[0076] The AN may provide a message 7108 to the NW, in particular the MME, indicating the UE capability information and / or support information provided by the UE, and / or the first power saving mode setting and / or the second power saving mode setting of the UE. In 7204, the NW updates the UE context based on the message 7108.
[0077] In some examples, the AN may also explicitly indicate to the UE whether the UE can operate in a power saving mode during an active period.
[0078] In 7203, the AN may transmit a message 7109 to the UE to release the UE to an idle state when it evaluates that there is no further primary signal to be communicated between the UE and the AN. In general, releasing the UE to an idle state may refer to releasing the UE to an RRC idle state or an RRC inactive state. Furthermore, in 7206, the AN may delete its UE context. The UE may enter the idle mode and enter a first power saving mode or a second power saving mode based on the procedure shown in FIG. 5. In particular, the UE may stop the primary receiver of the UE according to the first power saving mode or according to the second power saving mode by the low power wake-up receiver of the UE, and monitor for a low power wake-up signal in 7207.
[0079] The NW, particularly the AMF or MME, may receive incoming / downlink data (from an application, cloud, etc.) for the UE in FIG. 7 at 7114. The NW may then provide message 7110 to the AN to trigger the AN to provide said data to the UE. The AN may be the same as the one that exchanged one of messages 7101-7109 with the UE. However, it may be a different AN, as indicated by the time-stamp twist.
[0080] The NW may also provide a message 7111 indicating the UE context to the AN. At 7208, the AN may store the UE context. The UE context may include the first power saving mode setting and the second power saving mode setting, and information regarding the current power mode setting in which the UE operates.
[0081] Upon obtaining the first power saving mode configuration and / or the second power saving mode configuration and information regarding the power saving mode configuration used by the UE, the AN may transmit a respective low power wake-up signal. The type of the transmitted low power wake-up signal may indicate the next action to be performed by the UE (e.g., monitor for paging signals or initiate a RACH procedure).
[0082] The UE may detect and optionally decode the low power wake-up signal 7112 at 7209 and wake up the UE's primary transceiver at 7210 according to the current power saving mode.
[0083] Thereafter, in a primary signal time interval, the UE may receive a primary signal 7113, such as a paging signal. In particular, the UE may receive a primary signal corresponding to a DL control channel (eg, a paging PDCCH).
Claims
1. 1. A method for operating a mobile device UE in a power saving mode, comprising: Obtaining (4010) a first power saving mode setting indicating a time schedule of predefined main signal time intervals (3411, 3412, 3413) and a time schedule of predefined low power wake-up signal time intervals (3421, 3422, 3423) and a second power saving mode setting associated with an always-on operation; When the UE obtains (4020) a trigger for operating in a first power saving mode (3400), a step of operating (4030) the UE in the first power saving mode (3400), comprising: monitoring (4031) for a low power wake-up signal (3403) according to said time schedule of said predefined low power wake-up signal time intervals (3421, 3422, 3423); and in response to detecting a low power wakeup signal (3403) in one (3422) of the predefined low power wakeup signal time intervals (3421, 3422, 3423), communicating a primary signal in a primary signal time interval (3412) of the predefined primary signal time intervals (3411, 3412). When the UE obtains (4040) a trigger for operating in a second power saving mode (3500), a step of operating (4050) the UE in the second power saving mode (3500), comprising: A step (4051) of continuously monitoring a low power wake-up signal (3503); and in response to detecting a low power wake-up signal (3403), communicating (4052) a primary signal at a primary signal time interval (3512) dependent on a time at which the low power wake-up signal (3503) is detected.
2. providing a message to an access node AN indicating the UE supporting the first power saving mode (3400) and / or the second power saving mode (3500), The method of operating a UE in a power saving mode according to claim 1.
3. providing a message to the AN indicating a request to change the power saving mode; A method for operating a UE in a power saving mode according to claim 1 or 2.
4. The step of communicating a primary signal comprises: transmitting a main signal according to the detected type of low power wake-up signal; receiving a primary signal in response to the detected type of low power wake-up signal; and initiating a random access procedure depending on the type of the detected low power wake-up signal. A method for operating a UE in a power saving mode according to any one of claims 1 to 3.
5. obtaining a trigger for the UE to operate in the second power saving mode (3500), - evaluating, by the UE, a pre-determined criterion, in particular an upper limit on communication delay; and obtaining a message from an AN triggering the UE to operate in the second power saving mode (3500). A method for operating a UE in a power saving mode according to any one of claims 1 to 4.
6. obtaining a message from the AN triggering the UE to operate in the second power saving mode (3500); transmitting a primary signal to the UE; transmitting a low power wake-up signal to the UE. A method for operating a UE in a power saving mode according to claim 5.
7. The step of obtaining the first power saving mode setting and the second power saving mode setting includes: obtaining at least one message from an AN indicating the first power save mode setting and / or the second power save mode setting; A method for operating a UE in a power saving mode according to any one of claims 1 to 6.
8. In response to detecting a low power wakeup signal (3403) in one (3422) of the predefined low power wakeup signal time intervals (3421, 3422, 3423), a step (4032) of communicating a primary signal in a primary signal time interval (3412) of the predefined primary signal time intervals (3411, 3412, 3413) comprises: in response to detecting a low power wakeup signal (3403) in one of said predefined low power wakeup signal time intervals (3421, 3422, 3423), communicating (4032) a primary signal in a primary signal time interval (3412) of said predefined primary signal time intervals (3411, 3412, 3413) in response to said one (3422) of said predefined low power wakeup signal time intervals (3421, 3422, 3423) in which said low power wakeup signal (3403) is detected. A method for operating a UE in a power saving mode according to any one of claims 1 to 7.
9. A method of operating an access node (AN), comprising the steps of: Obtaining (5010) for a mobile device UE a first power saving mode setting indicating a time schedule of predefined main signal time intervals (3411, 3412, 3413) and a time schedule of predefined low power wake-up signal time intervals (3421, 3422, 3423) and a second power saving mode setting associated to an always-on operation, The step of operating the UE in a first power saving mode (3400) (4030) comprises: monitoring (4031) for a low power wake-up signal (3403) according to said time schedule of said predefined low power wake-up signal time intervals (3421, 3422, 3423); and in response to detecting a low power wakeup signal (3403) in one (3422) of the predefined low power wakeup signal time intervals (3421, 3422, 3423), communicating (4032) a primary signal in a primary signal time interval (3412) of the predefined primary signal time intervals (3411, 3412, 3413); The step of operating (4050) the UE in a second power saving mode (3500) comprises: Continuously monitoring (4051) for a low power wake-up signal (3403); a obtaining step (5010) including, in response to detecting the low power wake-up signal (3403), communicating (4052) a primary signal in a primary signal time interval (3512) dependent on the time of detecting the low power wake-up signal (3503); upon evaluating that the UE is operating in the first power saving mode (3400), sending (5031) a low power wake-up signal (3403) to the UE in accordance with the first power saving mode (3400); and upon evaluating that the UE is operating in the second power saving mode (3500), transmitting (5051) a low power wake-up signal (3503) to the UE in accordance with the second power saving mode (3500).
10. upon assessing that the UE is operating in the first power saving mode (3400), communicating (5032) a primary signal with the UE in one of the predefined primary signal time intervals (3412); and upon assessing that the UE is operating in the second power saving mode (3500), communicating (5032) a primary signal with the UE in a primary signal time interval (3512) dependent on a time of transmitting the low power wake-up signal (3503). A method of operating the AN of claim 9.
11. obtaining a message from the UE indicating that the UE supports the first power saving mode and / or the second power saving mode. A method of operating an AN according to claim 9 or 10.
12. obtaining a message from the UE indicating a request to change a power saving mode; and providing a message to the UE, the message triggering the UE to operate in a power saving mode according to the request to change the power saving mode. A method of operating an AN according to any one of claims 9 to 11.
13. providing a message to the UE triggering the UE to operate in a power saving mode according to the request to change the power saving mode; transmitting a primary signal to the UE; transmitting a low power wake-up signal to the UE. A method of operating the AN of claim 12.
14. - evaluating a criterion by said AN, in particular an upper bound on the required communication delay; and providing a message to the UE triggering the UE to operate in the second power saving mode (3500). A method of operating an AN according to any one of claims 9 to 13.
15. providing a message to the UE triggering the UE to operate in the second power saving mode (3500), transmitting a primary signal to the UE; transmitting a low power wake-up signal to the UE. A method of operating an AN according to claim 14.
16. The step of obtaining a first power saving mode setting includes: Adapting at least one of a time schedule in a predefined main signal time interval (3411, 3412) or a time schedule in a predefined low power wake-up signal time interval (3421, 3422) to an upper limit of communication delay, A method of operating an AN according to any one of claims 9 to 15.
17. A mobile device UE (2100) comprising a control circuit (2110), said control circuit (2110) being configured to execute the method according to any one of claims 1 to 8.
18. a main receiver (2121), in particular a main transceiver, adapted to communicate a main signal; and a low power wake-up receiver (2122) configured to detect a low power wake-up signal; The control circuit, and further configured to wake up the primary receiver (2121) during the primary signal time interval (3512) dependent on the time of detecting the low power wake-up signal (3503). The UE (2100) of claim 17.
19. the control circuitry is configured to activate the low power wake-up receiver (2122) continuously or only according to a predefined low power wake-up signal time interval; 19. The UE (2100) according to claim 17 or 18.
20. An access node AN comprising a control circuit, said control circuit being configured to perform a method according to any one of claims 9 to 16.