Measurement for low power mode

Abstract

A first apparatus (user equipment, mobile phone) receives, from a second apparatus (base station, access point), a configuration regarding a carrier selection for retaining a measurement of a carrier

Description

FIELDS

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices, apparatuses and computer readable storage medium for measurement for low power mode. BACKGROUND

[0002] Communication systems such as fifth generation (5G) systems are designed and developed targeting for both mobile telephony and vertical use cases. Besides latency, reliability, and availability, user equipment (UE) energy efficiency is also a concerning aspect for the communication systems. Currently, devices such as UE may need to be recharged per week or day, depending on individual’s usage time. In general, 5G devices consume tens of milliwatts in radio resource control (RRC) idle / inactive state and hundreds of milliwatts in RRC connected state. Designs to prolong battery life is a necessity for improving energy efficiency as well as for better user experience.

[0003] Energy efficiency is even more critical for UEs without a continuous energy source, e.g., UEs using small rechargeable and single coin cell batteries. Among vertical use cases, sensors and actuators are deployed extensively for monitoring, measuring, charging, etc. Generally, their batteries are not rechargeable and expected to last at least few years. Currently, UEs need to periodically wake up once per discontinuous reception (DRX) cycle, which dominates the power consumption in periods with no signaling or data traffic. If UEs are able to wake up only when they are addressed, e.g., by paging, power consumption could be dramatically reduced. This can be achieved by using a wakeup signal to trigger or wake-up a main radio of the UE. A separate receiver of the UE may have the ability to monitor wake-up signal with ultra-low power consumption. Main radio works for downlink reception as well as uplink transmission. Main radio is also responsible for cell (re)selection evaluation to ensure e.g., that the UE is camping on the best cell. Main radio can be set to different power state, such as a sleep mode. SUMMARY

[0004] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode; determine at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration; and perform at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: determine a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus; and transmit, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

[0006] In a third aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode; determining at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration; and performing at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0007] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: determining a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus; and transmitting, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

[0008] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for receiving, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode; means for determining at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration; and means for performing at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0009] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for determining a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus; and means for transmitting, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

[0010] In a seventh aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the third aspect.

[0011] In an eighth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the fourth aspect.

[0012] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0014] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0015] FIG. 2A and FIG. 2B illustrates example block diagrams of a first apparatus with a main radio and a wake-up receiver, respectively;

[0016] FIG. 3 illustrates an example signaling flow of measurement for low power mode according to some example embodiments of the present disclosure;

[0017] FIG. 4 illustrates another example signaling flow of measurement for low power mode according to some example embodiments of the present disclosure;

[0018] FIG. 5 illustrates another example signaling flow of measurement for low power mode according to some example embodiments of the present disclosure;

[0019] FIG. 6 illustrates a flowchart of a method implemented at a first apparatus according to some example embodiments of the present disclosure;

[0020] FIG. 7 illustrates a flowchart of a method implemented at a second apparatus according to some example embodiments of the present disclosure;

[0021] FIG. 8 illustrates a flowchart of a method implemented at a first apparatus according to some example embodiments of the present disclosure;

[0022] FIG. 9 illustrates a flowchart of a method implemented at a second apparatus according to some example embodiments of the present disclosure;

[0023] FIG. 10 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0024] FIG. 11 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0025] Throughout the drawings, the same or similar reference numerals represent the same or similar element. DETAILED DESCRIPTION

[0026] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0027] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0028] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0029] It shall be understood that although the terms “first,” “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0030] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0031] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step has to be performed immediately after “A” occurs and one or more intervening steps may be included.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0033] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0034] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0035] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as 6G, New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-loT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0036] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0037] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customerpremises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0038] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0039] As discussed above, energy efficiency is very critical for UEs without a continuous energy source, e.g., UEs using small rechargeable and single coin cell batteries. In some mechanisms, a wake-up signal (WUS) (also called low power WUS, LP-WUS) may be applied to trigger (e.g. wake-up) a main radio (MR) of a device. A separate receiver such as a low-power (LP) wake-up receiver (WUR) of the device may have the ability to monitor wake-up signals with ultra-low power consumption. Main radio works for downlink reception including e.g., synchronization signal block (SSB) / system information / paging / data / control signaling transmission and reception as well as for uplink transmission including e.g., data and control signaling transmission. Main radio is also responsible for cell (re)selection evaluation to ensure e.g. that the UE is camping on the best cell. Main radio may be set in different power state. For example, the main radio may be turned off or set to (deep) sleep unless it is turned on.

[0040] For Release-18, RAN agreed study item on low-power Wake-up Signal (WUS) and Receiver (WUR) for NR. The study evaluated the usage of an additional low-power wake-up receiver (LP-WUR) at the UE to reduce the overall UE power consumption. The defining principle behind this scheme is that the main radio / receiver (MR) of the UE can be put into a sleep mode (or even powered off) for power saving when not being needed for any processing (e.g., traffic / measurements) and then be easily woken up as and when required by the network upon the reception by the LP-WUR of a newly defined wake-up signal (WUS). Basically, the network triggers the UE to wake-up exactly when needed in an event-driven manner, by transmitting a special WUS to the UE, which is monitored by the dedicated low-power WUS receiver (LP-WUR) at the UE. When a UE receives the WUS, the WUR receiver can trigger the wake-up of the ordinary NR MR transceiver and communication can start. Thus, the ultra-low power receiver wakes up the main radio, otherwise, the main radio can be OFF or kept in a deep sleep mode. The assumption is that the low-power wake-up receiver can be operated in an always ‘on’ manner with very low power consumption. In fact, it is expected that it will consume significantly less power compared to the NR transceiver, by designing a simple (WUS) signal and the use of dedicated hardware for its monitoring, which is only able to receive the WUS.

[0041] In order to achieve the UE power saving gain by LP-WUS / WUR, the RRM measurement on serving cell and neighbouring cell via MR is relaxed or may be stopped when UE is using LP-WUS or MR is in ultra-deep sleep.

[0042] For Rei ease-19, a new work item was initiated to properly define and specify a WUS (studied in Release-18), to support the operation of UEs with LP-WUR was approved with the following objectives. > To specify an LP-WUS design commonly applicable to both IDLE / INACTIVE and CONNECTED modes. Specify OOK (OOK-1 and / or OOK-4) based LP-WUS with overlaid OFDM sequence(s) over OOK symbol. The LP-WUS design shall ensure that for IDLE / INACTIVE operation, the same information is delivered irrespective of LP-WUR type. The OFDM sequence can carry information. At least duty-cycled monitoring of LP-WUS is supported > For IDLE / INACTIVE modes, specify procedure and configuration of LP-WUS indicating paging monitoring triggered by LP-WUS, including at least configuration, sub-grouping and entry / exit condition for LP-WUS monitoring. Specify Low Power-Synchronization Signal (LP-SS) with periodicity with Yms for LP-WUR, for synchronization and / or RRM for serving cell. Specify further RRM relaxation of UE MR for both serving and neighbor cell measurements, and UE serving cell RRM measurement offloaded from MR to LP-WUR, including the necessary conditions. > For CONNECTED mode, specify procedures to allow UE MR PDCCH monitoring triggered by LP-WUS including activation and deactivation procedure of LP-WUS monitoring. > Specify the necessary RAN4 core requirement(s) to support the feature. Specify UE low-power wake-up receiver requirements, at least REFSENS, ACS and ASCS requirements with consideration of possible new methodology to assess the low-power wake-up receiver performance. Study and if necessary specify or support by declaration, the corresponding BS requirements, eg., dynamic range for LP-WUS / LP-SS. Current NR BS requirements is baseline. Specify necessary RRM requirements.

[0043] In some mechanisms, for the case where a UE supports PEI and PEI is configured by the gNB, after the UE receives LP-WUS indicating wake-up, it is up to UE implementation whether to monitor PEI or not. It is supported that the UE monitors the legacy PO after receiving LP-WUS indicating wake-up.

[0044] From RANI perspective, for the entry / exit conditions for LP-WUS monitoring in IDLE / inactive mode, The UE may start LP-WUS monitoring if o the serving cell measurement performed by the MR is above entry threshold(s), if configured by the gNB. If UE starts LP-WUS monitoring, it may stop the legacy PO monitoring before UE receives LP-WUS indicating wake-up. The UE monitors the legacy PO (and may monitor PEI) and may stop LP-WUS monitoring if the serving cell measurement performed by the LR is below exit threshold(s), if configured by the gNB. The entry / exit thresholds can be configured separately for different types of LR.

[0045] In some mechanisms, LP-WUS is intended to be used for the benefit of UE power saving. One approach for UE power saving is to offload some or all current measurements performed by the MR to the LR. There are currently various procedures, such as EMR / Fast CA / DC setup (aka idle / inactive measurements) which aim to assist both network and UE to perform measurements during and / or after connection initiation to enable fast data transmission (e.g. with fast Scell activation) upon connection setup / resume. The release-18 work on fast CA / DC setup also expanded the idle-mode procedures to cover cell reselection measurements. By using LP-WUS, the benefits of these features would be diminishing as there would be no measurements reports to provide to the network, since some or all measurements can be offloaded to LR and LR may not be able perform neighbour cell measurements. In some case even all MR measurements can be omitted when LP-WUS is used.

[0046] In some mechanisms, network may request the UE to measure NR and / or E-UTRA carriers in RRC IDLE or RRC INACTIVE via system information or via dedicated measurement configuration in RRCRelease. If the UE was configured to perform measurements of NR and / or E-UTRA carriers while in RRC IDLE or in RRCINACTIVE, it may provide an indication of the availability of corresponding measurement results to the gNB in the RRCSetupComplete message. The network may request the UE to report those measurements after security activation. The request for the measurements can be sent by the network immediately after transmitting the Security Mode Command (i.e. before the reception of the Security Mode Complete from the UE).

[0047] If the UE was configured to perform measurements of NR and / or E-UTRA carriers while in RRC INACTIVE, the gNB can request the UE to provide corresponding measurement results in the RRCResume message and then the UE can include the available measurement results in the RRCResumeComplete message. Alternatively, the UE may provide an indication of the availability of the measurement results to the gNB in the RRCResumeComplete message and the gNB can then request the UE to provide these measurement results.

[0048] However, how to enable UE to benefit from the low power WUS energy saving while allowing both network and UE to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode has become a concerning problem.

[0049] In order to solve at least part of the above problems or other potential problems, a solution on measurement for low power mode is proposed. According to embodiments of the present disclosure, a first apparatus such as a terminal device receives, from a second apparatus (such as a network device), a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode such as the LP-WUS mode and / or while LR is being used. The first apparatus determines at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration. The first apparatus performs at least one measurement of the at least one target carrier by a main radio of the first apparatus in the low power mode, and / or after the low power mode. In this way, the second apparatus may configure the first apparatus to select the target carrier for retaining in the low power mode. Thus, the first apparatus is enabled to benefit from the low power WUS energy saving while allowing both first and second apparatuses to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0050] In addition, another solution on measurement for low power mode is proposed. According to embodiments of the present disclosure, a first apparatus such as a terminal device determines at least one target carrier from a plurality of candidate carriers for retaining a measurement in a low power mode. The first apparatus performs at least one measurement of the at least one target carrier by a main radio of the first apparatus in the low power mode, and / or after the low power mode. With this solution, the first apparatus may autonomously select the target carrier for retaining the measurement. The target carrier may be autonomously selected from the configured list of carriers provided by the second apparatus (such as a network device). Thus, the first apparatus is enabled to benefit from the low power WUS energy saving while allowing both first and second apparatuses to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0051] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, a plurality of communication devices, including a first apparatus 110 and a second apparatus 120, can communicate with each other.

[0052] In the example of FIG. 1, the first apparatus 110 may include a terminal device and the second apparatus 120 may include a network device serving the terminal device. The serving area of the second apparatus 120 may be called as a cell 102.

[0053] It is to be understood that the number of devices and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of devices configured to implementing example embodiments of the present disclosure. Although not shown, it would be appreciated that one or more additional devices may be located in the cell 102, and one or more additional cells may be deployed in the communication environment 100. It is noted that although illustrated as a network device, the second apparatus 120 may be another device than a network device. Although illustrated as a terminal device, the first apparatus 110 may be a device other than a terminal device.

[0054] In the following, for the purpose of illustration, some example embodiments are described with the first apparatus 110 operating as a terminal device and the second apparatus 120 operating as a network device. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network device or other device, and operations described in connection with a network device may be implemented at a terminal device or other device.

[0055] In some example embodiments, if the first apparatus 110 is a terminal device and the second apparatus 120 is a network device, a link from the second apparatus 120 to the first apparatus 110 is referred to as a downlink (DL), while a link from the first apparatus 110 to the second apparatus 120 is referred to as an uplink (UL). In DL, the second apparatus 120 is a transmitting (TX) device (or a transmitter) and the first apparatus 110 is a receiving (RX) device (or a receiver). In UL, the first apparatus 110 is a TX device (or a transmitter) and the second apparatus 120 is a RX device (or a receiver).

[0056] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0057] In some example embodiments, the first apparatus 110 includes a main radio and a wake-up receiver such as a LP-WUR (LR). FIG. 2A and FIG. 2B respectively illustrate example block diagrams of the first apparatus 110 with a main radio 210 (for example, a NR transceiver) and an LP-WUR 220 (also referred to as a LP-WUS receiver). The LP-WUR 220 may monitor WUS(s) 230 from the network such as the second apparatus 120.

[0058] In some embodiments, the LP-WUR 220 may be operated in an always £on’ manner with very low power consumption. For example, the LP-WUR 220 may monitor the WUS 230 during an idle / inactive mode and a connected mode. The LP-WUR 220 may consume significantly less power compared to the main radio 210, by applying a simple WUS 230 and the use of dedicated hardware for its monitoring. For example, the LP- WUR 220 may be only able to or configured to receive the WUS 230. As shown in FIG. 2A, the WUS 230 is off, the main radio 210 of first apparatus 110 is in an off or deep sleep mode.

[0059] In some example embodiments, the second apparatus 120 such as a network device may trigger the first apparatus 110 to wake-up when needed in an event-driven manner, by transmitting a certain WUS 230 to the first apparatus 110. The WUS 230 may be monitored by the LP-WUR 220, for example, an ultra-low power receiver. As shown in FIG. 2B, in response to receiving the WUS(s) 230, the LP-WUR 220 may trigger the wake-up of the ordinary NR transceiver and communication / normal operation may start. For example, the LP-WUR 220 such as the ultra-low power receiver wakes up the main radio 210. The main radio 210 thus may be switched into an on state or a no sleep mode. Otherwise, the main radio 210 may be turned off or kept in a sleep mode, such as a deep sleep mode or an ultra-deep sleep mode.

[0060] As used herein, the turned off state, the turned-on state, sleep mode, a specific sleep mode among a plurality of different sleep modes, or no sleep mode of the main radio 210 may be referred to as a power state of the main radio 210. As used herein, the term “no sleep mode” may refer to a power state or mode in which the main radio 210 of the first apparatus 110 performs a channel monitoring and a channel measurement. The “no sleep mode” may also be referred to as a “normal mode” or “turned-on state”. The channel monitoring may refer to physical downlink control channel (PDCCH) monitoring, physical downlink shared channel (PDSCH) monitoring or any other suitable monitoring. Examples of the channel measurement may include but not limited to a radio resource management (RRM) measurement, a radio link monitoring (RLM) measurement, a beam failure detection (BFD) measurement, a channel state information (CSI) measurement, a beam management (BM) measurement, idle-mode measurement, and / or the like.

[0061] The main radio 210 power consumption depends on the configured length of wake-up periods, e.g., paging cycle. To meet the battery life requirements above, long eDRX cycle may be used, resulting in high latency, which is not suitable for such services with requirements of both long battery life and low latency. For example, in fire detection and extinguishment use case, fire shutters shall be closed and fire sprinklers shall be turned on by the actuators within 1 to 2 seconds from the time the fire is detected by sensors, long eDRX cycle cannot meet the delay requirements. eDRX is apparently not suitable for latency-critical use cases.

[0062] It is to be understood that although the main radio 210 and the LP-WUR 220 are shown as separate components in FIG. 2A and FIG. 2B, in some example embodiments, the LP-WUS 220 may be implemented as part of the main radio 210. That is, the corresponding part in the main radio 210 will be operated in an always ‘on’ manner with very low power consumption, while remaining part of the main radio 210 will be turned on and turned off for different scenarios.

[0063] As used herein, when describing “using low power mode or LP-WUS” or “first apparatus in low power mode or LP-WUS mode” or “during LP-WUS operation”, the following cases may be considered. A first case relates to MR offloading to LR. That is, the first apparatus 110 is offloading MR measurements to LR due to LP-WUS being used or configured. LR measurements are either Primary synchronization signal (PSS) or Secondary synchronization signal (SSS) based on LP-SS based. The offloading of MR may be full or partial. A second case relates to MR serving and / or neighbouring cell relaxation. That is, the first apparatus 110 is relaxing MR and / or LR measurements due to thresholds being met where such operation is allowed for the first apparatus 110. MR relaxation may mean that the measurements are more sparse than when in regular operation. A third case relates to LP-WUS monitoring. In this case, LR (or some implementations, some part of MR), is monitoring specific LP-WUS reference signal that wakes up the first apparatus 110. The first apparatus 110 is or has entered LP-WUS monitoring and LP-WUS monitoring is active. The assumption in this case is that the first apparatus 110 also supports LP-WUS monitoring capability.

[0064] FIG. 3 illustrates an example signaling flow 300 of measurement for low power mode according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 300 will be described with reference to FIG. 1, for example, by using the first apparatus 110 and the second apparatus 120.

[0065] In operation, the second apparatus 120 transmits (320), to the first apparatus 110, a configuration (also referred to as a “retain configuration”) regarding a carrier selection for retaining a measurement of a carrier in a low power mode. The first apparatus 110 receives (330) the configuration. That is, to assist the first apparatus 110 with the information on which carrier(s) to retain idle / inactive measurements, the second apparatus 120 may provide information and / or configuration to the first apparatus 110 on which carriers first apparatus 110 retain measurements when LP-WUR used.

[0066] As used herein, the term “retaining a carrier” or “retaining a measurement of a carrier” refers to that the first apparatus 110 may necessarily need to actively measure the carrier according to the (current) measurement requirements, if first apparatus 110 is operating in LP-WUS mode. Instead, the first apparatus 110 may implement various schemes to enable that the measurements are available when needed, i.e., if first apparatus 110 is returning to connected mode from the idle / inactive state. Retained means that the first apparatus 110 retains at least the carrier with the associated configuration information and performs at least one measurement during the idle / inactive state or while re-activating MR and entering connected mode, to verify that the carrier is still available (for example detectable). The measurements may be incrementally performed on top of old measurements. Additionally, the first apparatus 110 may perform measurements to verify if the associated (e.g., idle / inactive state) measurement (accuracy) requirements are met, or measure the number of samples indicated in the measurement accuracy requirements.

[0067] In some example embodiments, the configuration may be included in an RRC message, such as a dedicated RRC message or RRCRelease message. Alternatively, or in addition, the configuration may be included in system information such as a system information block (SIB) (also referred to as SIB-message). In some example embodiments, the dedicated RRC configuration may overwrite the SIB configuration, or vice versa. For example, the SIB configuration may overwrite the RRC Configuration if cell reselection occurs.

[0068] The first apparatus 110 determines (340) at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration. As used herein, the target carrier may be referred to as retained carrier or carrier to be retained.

[0069] The first apparatus 110 performs (350) at least one measurement of the at least one target carrier by the main radio 210 of the first apparatus 110 in the low power mode such as LP-WUS mode and / or after the low power mode. For example, the at least one measurement may be performed based on a low power synchronization signal (LP-SS) or any other suitable signal. In this way, the network may configure the retained carrier for the first apparatus 110.

[0070] In some example embodiments, the second apparatus 120 may determine (310) the configuration. For example, the second apparatus 120 may determine (310) the configuration based on at least one of: a previous measurement report received from the first apparatus 110, at least one candidate carrier used by the first apparatus 110 in a connected mode, at least one candidate carrier used in a time duration, a use of a primary secondary cell (PSCell) prior to a connection release of the first apparatus 110, a next best cell after a serving cell of the first apparatus 110, at least one candidate carrier on which the first apparatus 110 has an active data connection in a connected mode, loads and measurement qualities of a plurality of candidate carrier, measurement qualities of a plurality of candidate intra-frequency carrier, or measurement qualities of a plurality of candidate inter-frequency carrier.

[0071] That is, the second apparatus 120 may perform a retain carrier selection procedure prior to configuring the first apparatus 110 with the retain configuration. For example, the second apparatus 120 may select either an intra-frequency carrier, or interfrequency carrier to retain. If the first apparatus 110 has been using PSCell prior to the connection release, the second apparatus 120 may include both PCell and PSCell carriers in the retain configuration, this may also be included regardless of the first apparatus 110 usage of the PSCell. The selection may be based on previous measurement report. The selection may be based on carrier which has been the used most recently by the first apparatus 110. For example, a carrier that first apparatus 110 has used while in connected mode.

[0072] In an option, the second apparatus 120 may select the next best cell after the serving cell in the measurement report. In another option, the second apparatus 120 may select a carrier which the first apparatus 110 has had an active data connection in the connected mode. In a further option, the second apparatus 120 may select a carrier which has been the used most recently by the first apparatus 110. For example, a carrier that the first apparatus 110 has used while in connected mode.

[0073] In a further option, the second apparatus 120 may select a carrier which has the lowest load and exceeds a threshold (measurement quality is good enough). In a still further option, the second apparatus 120 may select g the best intra-frequency carrier based on first apparatus 110 measurements. In a further option, the second apparatus 120 may select the best inter-frequency carrier based on first apparatus 110 measurements.

[0074] It to be understood that these options are only for the purpose of illustrating, without suggesting any limitation. These options and any other suitable options may be applied separately, or in combination.

[0075] In some embodiments, the candidate carriers or the at least one target carrier may be pre-selected or predetermined.

[0076] In some cases, the “retain configuration” may also refer to the carriers that are not retained. That is, the second apparatus 120 may indicate which carriers should not be maintained. In the context of this disclosure, it is considered but not highlighted other than here.

[0077] In some example embodiments, the configuration may include at least one of: the at least one target carrier, a list of candidate carriers for an idle or inactive measurement, a primary cell (PCell), a primary secondary cell (PSCell), a type of intrafrequency carrier or a type of inter-frequency carrier, the number of the at least one target carrier, an indication of retaining a carrier, at least one candidate carrier measured by the main radio of the first apparatus 110 during an idle or inactive mode, a time length for retaining the measurement, a maximum number of the at least one target carrier, a minimum number of the at least one target carrier, or at least one condition for retaining the measurement in the low power mode. For example, the at least one condition may include a first condition that a signal strength of a signal from the second apparatus is below a threshold. The indication of retaining a carrier may be a flag. For example, the flag may indicate whether to retain the carrier.

[0078] In some example embodiments, the second apparatus 120 may provide the first apparatus 110 with at least one carrier which the first apparatus 110 retains (e.g. in a carrier list) for the idle / inactive measurements. The carrier may be associated with the same measurement identifier as idle-mode carrier. When this carrier is indicated, the first apparatus 110 retains the configuration of the other measurement configuration. In an embodiment, the second apparatus 120 may indicate exact carrier(s) to retain. In one embodiment, the second apparatus 120 may indicate it is an intra-frequency carrier that first apparatus 110 is required to retain. The second apparatus 120 may not specify which carrier but leaves this up to first apparatus 110 selection. In one embodiment, the second apparatus 120 indicates it is an inter-frequency carrier that first apparatus 110 is required to retain. The second apparatus 120 may not specify which carrier but leaves this up to first apparatus 110 selection.

[0079] In one embodiment, it is specified how many carriers the first apparatus 110 shall retain from idle / inactive measurement configuration. For example, 1st carrier or two 1st carriers or 3 1st carries and so on. In one example it is specified how many carriers the first apparatus 110 shall retain, and it is up to the first apparatus 110 implementation to select which ones to retain. In an embodiment, the second apparatus 120 indicates which carries shall be measured by MR for idle / inactive measurements.

[0080] In one example, the first apparatus 110 may be configured with a timer on how long the first apparatus 110 may retain / measure the carriers in LP-WUS operation. In one example, the first apparatus 110 is provided with a minimum number of carriers to retain / measure, and it is up to first apparatus 110 to select which carrier to retain.

[0081] In some example embodiments, if the at least one target carrier is on a same band or collocated with a serving cell carrier, the first apparatus 110 may determine to not retain the measurement of the at least one target carrier.

[0082] In some example embodiments, the first apparatus 110 may receive, from the second apparatus 120, a trigger message for performing an idle or inactive measurement. In response to receiving the trigger message, the first apparatus 110 may perform the measurement of the at least one target carrier by the main radio in the low power mode. By way of example, the trigger message is included in at least one of: a configuration of an idle mode measurement, a LP-WUS configuration, an LR measurement configuration, or a cell reselection configuration. The idle mode measurement may be an early measurement report (EMR) and / or a cell reselection measurement.

[0083] In some example embodiments, the configuration of the idle mode measurement such as early measurement report configuration is based on at least one of the following conditions: an LP-WUS entry condition, a LP-WUS exit condition, a relaxation condition, or a no-relaxation condition.

[0084] The first apparatus 110 with EMR capability such as EMR capable UE may be required to perform measurements in IDLE mode until T331 expires. The first apparatus 110 such as EMR UEs will maintain the cells detectable from the connected mode until the T331 timer expires. The time after T331 expires and the time until the first apparatus 110 receives the RRC setup / resume is unknown. After T331 expires, it is up to the first apparatus 110 implementation whether it maintains the cells detectable for early measurement reporting purposes. Based on UE information indication and network information request the first apparatus 110 reports the early measurement results after security is activated. After the first apparatus 110 has moved from RRC IDLE mode to RRC CONNECTED mode, the second apparatus 120 sends a measurement configuration to the first apparatus 110 indicating what the first apparatus 110 shall measure and how to report the measurements.

[0085] Measurement configuration may be provided using dedicated signalling i.e. RRCReconfiguration or RRCResume message. With the measurement configuration the network configures the first apparatus 110 to perform NR and / or inter-RAT measurements and tells how to report the measurement results based on SS / PBCH blocks and / or CSI-RS resources.

[0086] In some embodiments, LP-WUS and / or paging message addressing the first apparatus 110 triggers the first apparatus 110 to perform idle / inactive mode measurements. In some embodiments, a flag is included in the existing configuration for those carriers that first apparatus 110 shall retain / measure over LP-WUS period or when the first apparatus 110 is using LP-WUS. The flag may be included in the idle-mode measurement configuration. For example, either included in the EMR configuration or cell reselection configuration or both. Once the carrier is indicated in the configuration, the first apparatus 110 shall retain / measure that carrier regardless of LP-WUS operation (i.e., the carrier is not relaxed / and / or offloaded). For example, the first apparatus 110 shall measure the indicated carrier with MR if the carrier is either SCell or neighbouring cell carrier and LR does not support neighbouring cell measurements.

[0087] In some example embodiments, if the at least one target carrier comprises an early measurement report carrier, the first apparatus 110 may determine to retain the measurement of the at least one target carrier based on a behavior of the first apparatus 110. That is, if the carrier is EMR carrier, the first apparatus 110 may choose to retain or not to retain the carrier depending on the behavior. Alternatively, or in addition, if the at least one target carrier comprises a cell reselection carrier, the first apparatus 110 may determine to retain the measurement of the at least one target carrier. That is, if the carrier is cell reselection carrier, the first apparatus 110 shall retain the carrier.

[0088] In some embodiments the configuration indicates that it is only applied upon certain LP-WUS conditions, for instance a threshold is provided and if the threshold is met, the measurement retain configuration applies. For example, in some implementations of the proposed embodiment, the second apparatus 120 may configure or associate the first apparatus 110 with further thresholds which determine whether first apparatus 110 should do the idle-mode measurements. In some examples, the first apparatus 110 is not required to carry out idle-mode measurements if the first apparatus 110 is in LP-WUS operation state, i.e. if the DL signal level / quality has exceeded the thresholds associated to LP-WUS entry conditions. In reverse, if the DL signal level / quality has fallen below threshold associated to LP-WUS exit condition, the first apparatus 110 is required to carry out EMR related measurements. In some possible embodiments, the applicability of EMR measurements is related to the RRM relaxation thresholds. In additional implementations, the EMR measurement configuration may be different for different conditions (e.g. above LP-WUS entry, below LP-WUS exit, MR based RRM offloading / relaxation / no-relaxation) so that for example the number of carriers to be measured is less (or zero) if first apparatus 110 is in conditions where RRM relaxation (or offloading) is allowed.

[0089] An LP-WUS configuration may include a set of carriers. If the carriers overlap idle / inactive measurement carriers, first apparatus 110 shall retain at least one of the carriers. In one example the first apparatus 110 may select one of the configured carriers autonomously. In one example, the first apparatus 110 may select one of the configured carriers based on signal strength derived from measurements (e.g. connected mode or idlemode measurements).

[0090] The first apparatus 110 may select the at least one target carrier based on the configuration and a signal strength from at least one further measurement. In some example embodiments, the first apparatus 110 is required to retain the configured carrier (e.g., carrier is detectable, and measurable) during idle / inactive mode according to idlemode measurement requirements. The first apparatus 110 shall be able to report the carrier according to the corresponding reporting requirements.

[0091] The first apparatus 110 may perform (350) the measurement of the at least one target carrier based on at least one of: the LP-WUS configuration is received from the second apparatus 120, or a paging occasion (PO).

[0092] In one implementation scenario, the first apparatus 110 wakes up for listening LP-WUS occasions and / or paging occasions and performs a “retain measurements”, or a measurement on the specified carrier. The first apparatus 110 is not necessarily required to do this, but for first apparatus 110 it may be beneficial to track the carrier frequency during paging occasions in order to not needing to measure otherwise.

[0093] If the carrier that is configured is on the same or similar band than the serving cell carrier, and the cells are collocated, the first apparatus 110 does not measure the carrier but considers that the radio conditions are such that the carrier which is measured by the LR is similar. Hence, no need to perform measurements.

[0094] Upon receiving LP-WUS configuration, and / or considering that the paging is waking up the particular first apparatus 110, the first apparatus 110 performs the measurements on the retained carrier.

[0095] In some example embodiments, an RRC message for releasing to an idle mode comprises a first configuration regarding the carrier selection for retaining the measurement, and system information comprises a second configuration regarding the carrier selection for retaining the measurement. The first apparatus 110 may stop an LP-WUS operation and starting performing the measurement of the at least one target carrier based on one of: the first configuration or the second configuration. Alternatively, the first apparatus 110 may continue the LP-WUS operation without measuring the at least one target carrier.

[0096] In some example embodiments, if LP-WUS configuration is present simultaneously with idle-mode configuration, the first apparatus 110 may not use the LP-WUS relaxation (i.e., LP-WUS is disabled).

[0097] If one configuration is provided in when first apparatus 110 is released to idlemode, and the configuration is different from the SIB configuration, the first apparatus 110 may follow the SIB configuration.

[0098] In some cases, the first apparatus 110 may be required to stop LP-WUS operation and start performing measurements. In some cases, the first apparatus 110 may be allowed to continue the LP-WUS operation regardless of the SIB configuration.

[0099] In some example embodiments, if the first apparatus 110 receives one configuration in RRCRelease and SIB configuration updates, the first apparatus 110 may follow the SIB configuration or vice versa

[0100] In some example embodiments, the first apparatus 110 may transmit a report of the measurement of the at least one target carrier to the second apparatus 120. The second apparatus 120 may receive the measurement report.

[0101] Embodiments regarding configuring the first apparatus 110 to determine the target carrier for measurement in the low power mode have been described with respect to FIG. 3. With these embodiments, the second apparatus may configure the first apparatus to select the target carrier for retaining in the low power mode. Thus, the first apparatus is enabled to benefit from the low power WUS energy saving while allowing both first and second apparatuses to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0102] In order to solve at least part of the above problems or other potential problems, another solution on measurement for low power mode is proposed. In the solution, a first apparatus such as a terminal device determines at least one target carrier from a plurality of candidate carriers for retaining a measurement in a low power mode. The first apparatus performs the measurement of the at least one target carrier by a main radio of the first apparatus in the low power mode. With this solution, the first apparatus may autonomously select the target carrier for retaining the measurement. Thus, the first apparatus is enabled to benefit from the low power WUS energy saving while allowing both first and second apparatuses to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0103] FIG. 4 illustrates an example signaling flow 400 of measurement for low power mode according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 400 will be described with reference to FIG. 1, for example, by using the first apparatus 110 and the second apparatus 120. In the following description, it is assumed that the first apparatus 110 may include a main radio and a wake-up receiver, such as the main radio 210 and the LP-WUR 220 in FIG. 2A and FIG. 2B.

[0104] In operation, the first apparatus 110 determines (410) at least one target carrier from a plurality of candidate carriers for retaining a measurement in a low power mode. For example, in certain conditions, the first apparatus 110 may be allowed to autonomously select at least one carrier to retain for idle / inactive measurements if the first apparatus 110 is using LP-WUR and / or the first apparatus 110 has been configured with retain configuration.

[0105] In some example embodiments, the at least one target carrier may include at least one intra-frequency carrier. In one embodiment, the first apparatus 110 may be required to select Nintra carrier that is intra-frequency carrier, and where Nintra is at least one. Alternatively, or in addition, the at least one target carrier may include at least one interfrequency carrier. In one embodiment, the first apparatus 110 may be required to select Ninter carrier that is inter-frequency carrier, and where Ninteris at least one.

[0106] In one embodiment, the first apparatus 110 follows the EMR configuration, and autonomously selects N carriers to retain, where N is at least 1. In one embodiment, the first apparatus 110 follows non-EMR (i.e., cell reselection) configuration, and autonomously selects N carriers to retain, where N is at least 1.

[0107] In some example embodiments, at least one of a type of intra-frequency carrier, a type of inter-frequency carrier, the number of the at least one intra-frequency carrier or the number of the at least one inter-frequency carrier is predefined. Table 1 illustrates an example of a standard defining the type of the carrier and the number of the carrier. It is to be understood that the types of carriers, the number of carriers of different types, and the parameters in Table 1 are only for the purpose of illustration, without suggesting any limitation. Any suitable type of carrier with any suitable number of carrier may be applied. Scope of the present disclosure is not limited here. Table 1 Number of cells to measure When UE is operating in LP-WUS mode, and when configured by higher layers, the UE is required to retain at least Nintra and / or Ninter carriers configured in measIdleCarrierListEUTRA-r 16 and / or measReselectionCarrierlElXR-r 18, where Nintra = 1 ■ Ninter = 1.

[0108] In some example embodiments, in response to receiving at least one of: an early measurement report configuration or a cell reselection configuration, the first apparatus 110 may select the at least one target carrier.

[0109] The first apparatus 110 performs (420) at least one measurement of the at least one target carrier by a main radio of the first apparatus 110 in the low power mode and / or after the low power mode such as LP-WUS mode.

[0110] In some example embodiments, if the at least one target carrier is on a same band or collocated with a serving cell carrier, the first apparatus 110 may determine to not retain the measurement of the at least one target carrier.

[0111] In some example embodiments, the first apparatus 110 may receive, from the second apparatus 120, a trigger message for performing an idle or inactive measurement. In response to receiving the trigger message, the first apparatus 110 may perform (420) the measurement of the at least one target carrier by the main radio in the low power mode. By way of example, the trigger message is included in at least one of: a configuration of an idle mode measurement such as an early measurement report configuration or a cell reselection measurement configuration, an LP-WUS configuration, a LR measurement configuration, a cell reselection configuration, or the like.

[0112] In some example embodiments, if the at least one target carrier comprises an early measurement report carrier, the first apparatus 110 may determine to retain the measurement of the at least one target carrier based on a behavior of the first apparatus 110. Alternatively, or in addition, in some example embodiments, if the at least one target carrier comprises a cell reselection carrier, the first apparatus 110 may determine to retain the measurement of the at least one target carrier.

[0113] In some example embodiments, the first apparatus 110 may perform (420) the measurement of the at least one target carrier based on at least one of: the LP-WUS configuration received from the second apparatus, or a paging occasion.

[0114] In some example embodiments, the first apparatus 110 may transmit (430) a report of the measurement of the at least one target carrier to the second apparatus 120. The second apparatus 120 may receive (440) the measurement report.

[0115] With these embodiments, the first apparatus may autonomously select the target carrier for retaining the measurement. Thus, the first apparatus is enabled to benefit from the low power WUS energy saving while allowing both first and second apparatuses to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0116] FIG. 5 illustrates an example signaling flow 500 of measurement for low power mode according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 500 will be described with reference to FIG. 1, for example, by using the first apparatus 110, a serving cell 502 (such as the cell 102) and a SCell 504 (such as a neighboring cell) of the second apparatus 120. In the following description, it is assumed that the first apparatus 110 may include a main radio and a wake-up receiver, such as the main radio 210 and the LP-WUR 220 in FIG. 2A and FIG. 2B.

[0117] In operation, the first apparatus 110 may be in an RRC CONEECTED mode. In the RRCCONEECTED mode, the second apparatus 120 may transmit (510) a configuration to the first apparatus 110 via the serving cell 502. The first apparatus 110 receives (515) the configuration. For example, the configuration may include RRCConnectionRelease message together with an LP-WUS configuration, an idle-mode configuration and a retain configuration. That is, the first apparatus 110 may be provided with retain config, either together with EMR or LP-WUS configuration or independently.

[0118] Next, the first apparatus 110 may be in an RRC IDLE or RRC1NACTIVE mode. In such mode, the second apparatus 120 may transmit (520) a further configuration to the first apparatus 110 via the serving cell 502. The first apparatus 110 receives (525) the further configuration. For example, the further configuration may include SIB configuration together with the LP-WUS configuration, the idle-mode configuration and the retain configuration. That is, the first apparatus 110 may also be provided the configuration via system information broadcast message. The first apparatus 110 may read the SIB and get the configuration in idle-mode. The first apparatus 110 may be provided with retain configuration, either together with EMR or LP-WUS configuration or independently.

[0119] In some example embodiments, in response to receiving (515 / 525) the configuration including the retain configuration, the first apparatus 110 may process the configuration directly once reading the retain configuration.

[0120] The first apparatus 110 may perform (530) an MR relaxation or MR measurement. In an example, the first apparatus 110 may enter MR relaxation. In another example, the first apparatus 110 may perform the MR measurement offloading to LR and / or LP-WUS. The first apparatus 110 may maintain the configured idle-mode. That is, conditions are such that the first apparatus 110 is allowed to enter one or more of the following: MR relaxation, or MR measurement offloading to LR.

[0121] The first apparatus 110 may monitor (535) an LP-WUS. For example, the first apparatus 110 starts monitoring LP-WUS.

[0122] The first apparatus 110 retains (540) the at least one target carrier. The at least one target carrier may be determined based on the received (515) configuration and the received (525) further configuration. For example, the first apparatus 110 may retain (540) the configured idle-mode carriers according to the configuration in RRCRelease and / or SIB. Retain configuration may be activated. If the first apparatus 110 enters the LP-WUS mode, the first apparatus 110 is reading the configuration and retains the carriers associated with the configuration. The retain in this case may mean that the first apparatus 110 measures the carriers every once in a while to make sure that the carriers are available for measurements when needed (e.g., when existing LP-WUS mode).

[0123] In some example embodiments, the second apparatus 120 may transmit (545) measurements to the first apparatus 110 via the SCell 504 such as a neighboring cell. The first apparatus 110 may receive (550) the measurements, such as SSB or LP-SS. If the retain configuration contains a serving cell carrier, while in LP-WUS mode, the first apparatus 110 performs retain measurements for the indicated reference signal. The measurements may be more sparse than the measurements first apparatus 110 would do if not in LP-WUS mode. If the measurements are neighbouring cell measurements, MR performs these measurements and they are LP-SS based.

[0124] In some example embodiments, the second apparatus 120 may transmit (555) measurements to the first apparatus 110 via the serving cell 502. The first apparatus 110 may receive (560) the measurements, such as SSB or LP-SS. While in LP-WUS mode, if the serving cell measurements have been offloaded to LR, the LR performs the measurements. LP-SS or PSS / SSS may be used.

[0125] In some example embodiments, the second apparatus 120 may transmit (565) an LP-WUS indication to the first apparatus 110 via the serving cell 502. The first apparatus 110 may receive (570) the LP-WUS indication.

[0126] In some example embodiments, the first apparatus 110 may check (575) a PO occasion. The first apparatus 110 may check (575) if the PO occasions is for the first apparatus 110 and based on the configuration or further configuration, start or continue measurements for the indicated carrier(s). The first apparatus 110 may check (575) if the PO occasion is for first apparatus 110 and based on configuration, the first apparatus 110 may start or continue measurements for the indicated carrier(s). The first apparatus 110 may start or continue or restart measurements for the carriers indicated in the retain configuration.

[0127] In some example embodiments, the first apparatus 110 may perform (580) a connection setup and EMR validity check with the second apparatus 120.

[0128] The first apparatus 110 may turn into the RRC CONNECTED mode. In the RRC COWECTED mode, the first apparatus 110 may transmit (585), to the second apparatus 120 via the serving cell 502, a measurement repot. The second apparatus 120 may receive (590) the measurement repot via the serving cell 502. Since the first apparatus 110 has been retaining the configured measurements, over the LP-WUS mode, the first apparatus 110 may be able to report measurements with measurement reporting, for example, in RRC connection setup (e.g., when coming from inactive mode), or by first apparatus 110 information request / response.

[0129] In some example embodiments, the first apparatus 110 may perform (595) a possible CA setup with the second apparatus 120. For example, the second apparatus 120 such as the network may set up CA using the measurements.

[0130] The requirements of measurement report for fast CA / DC setup apply for: > the first apparatus 110 supporting [Measurement validation based on EMR measurement] and configured with measIdleCarrierListNR-rl6 measIdleCarrierListEUTRA-rl6 by higher layers; and / or > the first apparatus 110 supporting [Measurement validation based on non-EMR measurement] and idle!nactiveNR-MeasReport-rl6 or idlelnactiveEUTRA-MeasReport-rl6 shall report based on the idle mode measurement which is specified in a standard, and according to the measurement reporting requirements specified in a standard.

[0131] The first apparatus 110 supporting [Measurement validation based on non-EMR measurement] shall report based on the idle mode measurement specified in a standard, and according to the measurement reporting requirements specified in a standard. The first apparatus 110 may not be required to report for fast CA / DC setup from any measurements during IDLE mode for carriers which are not configured by higher layers.

[0132] The first apparatus 110 shall perform validity check and report valid measurement results: > if the first apparatus 110 is supporting [Measurement validation based on EMR measurement] and measldleValidityDuration-r 18 is configured for carriers in measIdleCarrierListNR-r 16 or measIdleCarrierListEUTRA-r 16, and / or > if the first apparatus 110 is supporting [Measurement validation based on non-EMR measurement] and measReselectionValidityDuration-r 18 is configured for carriers in measResel ectionCarrierListNR-r 18

[0133] The measurement results are considered valid if the following conditions are met for the validity check: > the measurements are performed before msgl transmission for RRC resume / setup request within the last: > measIdleValidityDuration-rl8 seconds for carriers configured in meas!dleCarrierListNR-rl6 or measIdleCarrierListEUTRA-rl6, and / or > measReselectionValidityDuration-rl8 seconds for carriers configured in measReselectionCarrierListNR-rl8, > the measurement results satisfy measurement accuracy requirement at the measurement instance.

[0134] Otherwise, the measurement results are considered invalid. The first apparatus 110 shall not report invalid measurement results when measIdleValidityDuration-r 18 and / or measReselectionValidityDur ation-r 18 is configured.

[0135] If the measIdleValidityDuration-r 18 is not configured, the first apparatus 110 is not required to perform validity check for carriers in measIdleCarrierListNR-r 16 and meas!dleCarrierListEUTRA-rl6, and the first apparatus 110 may report measurement results given the measurement results satisfy measurement accuracy requirement at the measurement instance.

[0136] If the measReselectionValidityDur ation-r 18 is not configured, the first apparatus 110 is not required to perform validity check for carriers configured in measReselectionCarrierListNR-rl8, and the first apparatus 110 may report measurement results given the measurement results satisfy measurement accuracy requirement at the measurement instance.

[0137] Reference signal received power (RSRP), reference signal received quality (RSRQ) measurements contained in the measurement reports shall meet the corresponding accuracy requirements at the measurement instance specified in a standard.

[0138] These embodiments enable the first apparatus 110 to benefit from the low power WUS energy saving while allowing both the second apparatus 120 and the first apparatus 110 to benefit from fast connections setup with fast Scell(s) activation upon entering connected mode.

[0139] It is to be understood that the signaling flows 300, 400, and / or 500 may be applied separately, or in any combination. Embodiments of the present disclosure are not limited in this regard.

[0140] FIG. 6 shows a flowchart of an example method 600 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0141] At block 610, the first apparatus 110 receives, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode.

[0142] At block 620, the first apparatus 110 determines at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration.

[0143] At block 630, the first apparatus 110 performs at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0144] In some example embodiments, the configuration is included in at least one of a radio resource control message, or system information.

[0145] In some example embodiments, the configuration comprises at least one of: the at least one target carrier, a list of candidate carriers for an idle or inactive measurement, a primary cell (PCell), a primary secondary cell (PSCell), a type of intra-frequency carrier or a type of inter-frequency carrier, the number of the at least one target carrier, an indication of retaining a carrier, at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode, a time length for retaining the measurement, a maximum number of the at least one target carrier, a minimum number of the at least one target carrier, or at least one condition for retaining the measurement in the low power mode.

[0146] In some example embodiments, the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

[0147] In some example embodiments, the method 600 further comprises: selecting the at least one target carrier based on the configuration and a signal strength from at least one further measurement.

[0148] In some example embodiments, the method 600 further comprises: in accordance with a determination that the at least one target carrier is on a same band or collocated with a serving cell carrier, determining to not retain the measurement of the at least one target carrier.

[0149] In some example embodiments, the method 600 further comprises: receiving, from the second apparatus, a trigger message for performing an idle or inactive measurement; and in response to receiving the trigger message, performing at least one measurement of the at least one target carrier by the main radio in the low power mode.

[0150] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0151] In some example embodiments, the configuration of the idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a norelaxation condition.

[0152] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0153] In some example embodiments, the method 600 further comprises: in accordance with a determination that the at least one target carrier comprises a carrier for an idle or inactive mode, determining to retain the measurement of the at least one target carrier.

[0154] In some example embodiments, the method 600 further comprises: in accordance with a determination that the carrier for the idle or inactive mode comprises an early measurement report carrier, determining to retain the measurement of the early measurement report carrier based on a behavior of the first apparatus; and / or in accordance with a determination that the carrier for the idle or inactive mode comprises a cell reselection carrier, determining to retain the measurement of the cell reselection carrier.

[0155] In some example embodiments, the method 600 further comprises: performing the at least one measurement of the at least one target carrier based on at least one of:a low power wake up signal (LP-WUS) configuration, or low power radio (LR) configuration, being received from the second apparatus, or a paging occasion.

[0156] In some example embodiments, a radio resource control message for releasing to an idle mode comprises a first configuration regarding the carrier selection for retaining the measurement, and system information comprises a second configuration regarding the carrier selection for retaining the measurement, the first apparatus is caused to perform one of: stopping a low power wake up signal (LP-WUS) operation and starting performing the measurement of the at least one target carrier based on one of: the first configuration or the second configuration; or continuing the LP-WUS operation without measuring the at least one target carrier.

[0157] In some example embodiments, the at least one measurement of the at least one target carrier is performed based on a low power synchronization signal.

[0158] In some example embodiments, the method 600 further comprises: transmitting a report of the measurement of the at least one target carrier to the second apparatus.

[0159] FIG. 7 shows a flowchart of an example method 700 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0160] At block 710, second apparatus 120 determines a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus.

[0161] At block 720, second apparatus 120 transmits, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

[0162] In some example embodiments, the configuration is transmitted via at least one of: a radio resource control message, or system information.

[0163] In some example embodiments, the configuration comprises at least one of: the at least one target carrier, a list of candidate carriers for an idle or inactive measurement, a primary cell (PCell), a primary secondary cell (PSCell), a type of intra-frequency carrier or a type of inter-frequency carrier, the number of the at least one target carrier, an indication of retaining a carrier, at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode, a time length for retaining the measurement, a maximum number of the at least one target carrier, a minimum number of the at least one target carrier, or at least one condition for retaining the measurement in the low power mode.

[0164] In some example embodiments, the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

[0165] In some example embodiments, the method 700 further comprises: determine the configuration based on at least one of: a previous measurement report received from the first apparatus, at least one candidate carrier used by the first apparatus in a connected mode, at least one candidate carrier used in a time duration, a use of a primary secondary cell (PSCell) prior to a connection release of the first apparatus, a next best cell after a serving cell of the first apparatus, at least one candidate carrier on which the first apparatus has an active data connection in a connected mode, loads and measurement qualities of a plurality of candidate carrier, measurement qualities of a plurality of candidate intra-frequency carrier, or measurement qualities of a plurality of candidate inter-frequency carrier.

[0166] In some example embodiments, the second apparatus is cause to: in accordance with a determination that the PSCell is used prior to the connection release, add the PSCell and a primary cell (PCell) in the configuration.

[0167] In some example embodiments, the method 700 further comprises: transmitting, to the first apparatus, a trigger message for performing an idle or inactive measurement.

[0168] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0169] In some example embodiments, the configuration of an idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a norelaxation condition.

[0170] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0171] In some example embodiments, the method 700 further comprises: receiving a report of the measurement of the at least one target carrier from the first apparatus.

[0172] In some example embodiments, a first apparatus capable of performing any of the method 600 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0173] In some example embodiments, the first apparatus comprises means for receiving, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode; means for determining at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration; and means for performing at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0174] In some example embodiments, the configuration is included in at least one of: a radio resource control message, or system information.

[0175] In some example embodiments, the configuration comprises at least one of: the at least one target carrier, a list of candidate carriers for an idle or inactive measurement, a primary cell (PCell), a primary secondary cell (PSCell), a type of intra-frequency carrier or a type of inter-frequency carrier, the number of the at least one target carrier, an indication of retaining a carrier, at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode, a time length for retaining the measurement, a maximum number of the at least one target carrier, a minimum number of the at least one target carrier, or at least one condition for retaining the measurement in the low power mode.

[0176] In some example embodiments, the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

[0177] In some example embodiments, the first apparatus further comprises: means for selecting the at least one target carrier based on the configuration and a signal strength from at least one further measurement.

[0178] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the at least one target carrier is on a same band or collocated with a serving cell carrier, determining to not retain the measurement of the at least one target carrier.

[0179] In some example embodiments, the first apparatus further comprises: means for receiving, from the second apparatus, a trigger message for performing an idle or inactive measurement; and means for in response to receiving the trigger message, performing at least one measurement of the at least one target carrier by the main radio in the low power mode.

[0180] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0181] In some example embodiments, the configuration of the idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a no-relaxation condition.

[0182] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0183] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the at least one target carrier comprises a carrier for an idle or inactive mode, determining to retain the measurement of the at least one target carrier.

[0184] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the carrier for the idle or inactive mode comprises an early measurement report carrier, determining to retain the measurement of the early measurement report carrier based on a behavior of the first apparatus; and / or means for in accordance with a determination that the carrier for the idle or inactive mode comprises a cell reselection carrier, determining to retain the measurement of the cell reselection carrier.

[0185] In some example embodiments, the first apparatus further comprises: means for performing the at least one measurement of the at least one target carrier based on at least one of: a low power wake up signal (LP-WUS) configuration, or low power radio (LR) configuration, being received from the second apparatus, or a paging occasion.

[0186] In some example embodiments, a radio resource control message for releasing to an idle mode comprises a first configuration regarding the carrier selection for retaining the measurement, and system information comprises a second configuration regarding the carrier selection for retaining the measurement, the first apparatus is caused to perform one of: stopping a low power wake up signal (LP-WUS) operation and starting performing the measurement of the at least one target carrier based on one of: the first configuration or the second configuration; or continuing the LP-WUS operation without measuring the at least one target carrier.

[0187] In some example embodiments, the at least one measurement of the at least one target carrier is performed based on a low power synchronization signal.

[0188] In some example embodiments, the first apparatus further comprises: means for transmitting a report of the measurement of the at least one target carrier to the second apparatus.

[0189] In some example embodiments, a second apparatus capable of performing any of the method 700 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0190] In some example embodiments, the second apparatus comprises means for determining a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus; and means for transmitting, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

[0191] In some example embodiments, the configuration is transmitted via at least one of: a radio resource control message, or system information.

[0192] In some example embodiments, the configuration comprises at least one of: the at least one target carrier, a list of candidate carriers for an idle or inactive measurement, a primary cell (PCell), a primary secondary cell (PSCell), a type of intra-frequency carrier or a type of inter-frequency carrier, the number of the at least one target carrier, an indication of retaining a carrier, at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode, a time length for retaining the measurement, a maximum number of the at least one target carrier, a minimum number of the at least one target carrier, or at least one condition for retaining the measurement in the low power mode.

[0193] In some example embodiments, the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

[0194] In some example embodiments, the second apparatus further comprises: determine the configuration based on at least one of: a previous measurement report received from the first apparatus, at least one candidate carrier used by the first apparatus in a connected mode, at least one candidate carrier used in a time duration, a use of a primary secondary cell (PSCell) prior to a connection release of the first apparatus, a next best cell after a serving cell of the first apparatus, at least one candidate carrier on which the first apparatus has an active data connection in a connected mode, loads and measurement qualities of a plurality of candidate carrier, measurement qualities of a plurality of candidate intra-frequency carrier, or measurement qualities of a plurality of candidate inter-frequency carrier.

[0195] In some example embodiments, the second apparatus is cause to: in accordance with a determination that the PSCell is used prior to the connection release, add the PSCell and a primary cell (PCell) in the configuration.

[0196] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, a trigger message for performing an idle or inactive measurement.

[0197] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0198] In some example embodiments, the configuration of an idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a no-relaxation condition.

[0199] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0200] In some example embodiments, the second apparatus further comprises: means for receiving a report of the measurement of the at least one target carrier from the first apparatus.

[0201] FIG. 8 shows a flowchart of an example method 800 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0202] At block 810, the first apparatus 110 determines at least one target carrier from a plurality of candidate carriers for retaining a measurement in a low power mode.

[0203] At block 820, the first apparatus 110 performs at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0204] In some example embodiments, the at least one target carrier comprises at least one of: at least one intra-frequency carrier, and / or at least one inter-frequency carrier.

[0205] In some example embodiments, at least one of: a type of intra-frequency carrier, a type of inter-frequency carrier, the number of the at least one intra-frequency carrier or the number of the at least one inter-frequency carrier is predefined.

[0206] In some example embodiments, the method 800 further comprises: in response to receiving at least one of: an early measurement report configuration or a cell reselection configuration, selecting the at least one target carrier.

[0207] In some example embodiments, the method 800 further comprises: in accordance with a determination that the at least one target carrier is on a same band or collocated with a serving cell carrier, determining to not retain the measurement of the at least one target carrier.

[0208] In some example embodiments, the method 800 further comprises: receiving, from a second apparatus, a trigger message for performing an idle or inactive measurement; and in response to receiving the trigger message, performing the measurement of the at least one target carrier by the main radio in the low power mode.

[0209] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0210] In some example embodiments, the configuration of the idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a norelaxation condition.

[0211] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0212] In some example embodiments, the method 800 further comprises: in accordance with a determination that the at least one target carrier comprises a carrier for an idle or inactive mode, determining to retain the measurement of the at least one target carrier.

[0213] In some example embodiments, the method 800 further comprises: in accordance with a determination that the carrier for the idle or inactive mode comprises an early measurement report carrier, determining to retain the measurement of the early measurement report carrier based on a behavior of the first apparatus; and / or in accordance with a determination that the carrier for the idle or inactive mode comprises a cell reselection carrier, determining to retain the measurement of the cell reselection carrier.

[0214] In some example embodiments, the method 800 further comprises: performing the measurement of the at least one target carrier based on at least one of: a low power wake up signal (LP-WUS) configuration or a low power receiver (LR) measurement configuration being received from the second apparatus, or a paging occasion.

[0215] In some example embodiments, the at least one measurement of the at least one target carrier is performed based on a low power synchronization signal.

[0216] In some example embodiments, the method 800 further comprises: transmitting a report of the measurement of the at least one target carrier to a second apparatus.

[0217] FIG. 9 shows a flowchart of an example method 900 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0218] At block 910, the second apparatus 120 receives, from a first apparatus, a report of at least one measurement of at least one target carrier, the measurement being performed by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0219] In some example embodiments, the at least one target carrier comprises at least one of: at least one intra-frequency carrier, or at least one inter-frequency carrier.

[0220] In some example embodiments, at least one of: a type of intra-frequency carrier, a type of inter-frequency carrier, the number of the at least one intra-frequency carrier or the number of the at least one inter-frequency carrier is predefined.

[0221] In some example embodiments, the method 900 further comprises: transmitting, to the first apparatus, at least one of: an early measurement report configuration or a cell reselection configuration.

[0222] In some example embodiments, the method 900 further comprises: transmitting, to the first apparatus, a trigger message for performing an idle or inactive measurement, wherein the measurement of the at least one target carrier by the main radio in the low power mode is triggered by the trigger message.

[0223] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0224] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0225] In some example embodiments, a first apparatus capable of performing any of the method 800 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0226] In some example embodiments, the first apparatus comprises means for determining at least one target carrier from a plurality of candidate carriers for retaining a measurement in a low power mode; and means for performing at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0227] In some example embodiments, the at least one target carrier comprises at least one of: at least one intra-frequency carrier, and / or at least one inter-frequency carrier.

[0228] In some example embodiments, at least one of: a type of intra-frequency carrier, a type of inter-frequency carrier, the number of the at least one intra-frequency carrier or the number of the at least one inter-frequency carrier is predefined.

[0229] In some example embodiments, the first apparatus further comprises: means for in response to receiving at least one of: an early measurement report configuration or a cell reselection configuration, selecting the at least one target carrier.

[0230] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the at least one target carrier is on a same band or collocated with a serving cell carrier, determining to not retain the measurement of the at least one target carrier.

[0231] In some example embodiments, the first apparatus further comprises: means for receiving, from a second apparatus, a trigger message for performing an idle or inactive measurement; and means for in response to receiving the trigger message, performing the measurement of the at least one target carrier by the main radio in the low power mode.

[0232] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0233] In some example embodiments, the configuration of the idle mode measurement is based on at least one of the following conditions: a low power wake up signal (LP-WUS) entry condition, a LP-WUS exit condition, a relaxation condition, or a no-relaxation condition.

[0234] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0235] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the at least one target carrier comprises a carrier for an idle or inactive mode, determining to retain the measurement of the at least one target carrier.

[0236] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the carrier for the idle or inactive mode comprises an early measurement report carrier, determining to retain the measurement of the early measurement report carrier based on a behavior of the first apparatus; and / or means for in accordance with a determination that the carrier for the idle or inactive mode comprises a cell reselection carrier, determining to retain the measurement of the cell reselection carrier.

[0237] In some example embodiments, the first apparatus further comprises: means for performing the measurement of the at least one target carrier based on at least one of: a low power wake up signal (LP-WUS) configuration or a low power receiver (LR) measurement configuration being received from the second apparatus, or a paging occasion.

[0238] In some example embodiments, the at least one measurement of the at least one target carrier is performed based on a low power synchronization signal.

[0239] In some example embodiments, the first apparatus further comprises: means for transmitting a report of the measurement of the at least one target carrier to a second apparatus.

[0240] In some example embodiments, a second apparatus capable of performing any of the method 900 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0241] In some example embodiments, the second apparatus comprises means for receiving, from a first apparatus, a report of at least one measurement of at least one target carrier, the measurement being performed by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

[0242] In some example embodiments, the at least one target carrier comprises at least one of: at least one intra-frequency carrier, or at least one inter-frequency carrier.

[0243] In some example embodiments, at least one of: a type of intra-frequency carrier, a type of inter-frequency carrier, the number of the at least one intra-frequency carrier or the number of the at least one inter-frequency carrier is predefined.

[0244] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, at least one of: an early measurement report configuration or a cell reselection configuration.

[0245] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, a trigger message for performing an idle or inactive measurement, wherein the measurement of the at least one target carrier by the main radio in the low power mode is triggered by the trigger message.

[0246] In some example embodiments, the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

[0247] In some example embodiments, the idle mode measurement comprises at least one of: an early measurement report configuration, or a cell reselection measurement.

[0248] FIG. 10 is a simplified block diagram of a device 1000 that is suitable for implementing example embodiments of the present disclosure. The device 1000 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processor 1010, and one or more communication modules 1040 coupled to the processor 1010.

[0249] The communication module 1040 is for bidirectional communications. The communication module 1040 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1040 may include at least one antenna.

[0250] The processor 1010 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1000 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0251] The memory 1020 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1024, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1022 and other volatile memories that will not last in the power-down duration.

[0252] A computer program 1030 includes computer executable instructions that are executed by the associated processor 1010. The instructions of the program 1030 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 1030 may be stored in the memory, e.g., the ROM 1024. The processor 1010 may perform any suitable actions and processing by loading the program 1030 into the RAM 1022.

[0253] The example embodiments of the present disclosure may be implemented by means of the program 1030 so that the device 1000 may perform any process of the disclosure as discussed with reference to FIG. 3 to FIG. 9. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0254] In some example embodiments, the program 1030 may be tangibly contained in a computer readable medium which may be included in the device 1000 (such as in the memory 1020) or other storage devices that are accessible by the device 1000. The device 1000 may load the program 1030 from the computer readable medium to the RAM 1022 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e g., RAM vs. ROM).

[0255] FIG. 11 shows an example of the computer readable medium 1100 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1100 has the program 1030 stored thereon.

[0256] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0257] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0258] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0259] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0260] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0261] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of 5 a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0262] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features 10 or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to:receive, from a second apparatus, a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode;determine at least one target carrier for measurement retaining from a plurality of candidate carriers based on the configuration; andperform at least one measurement of the at least one target carrier by a main radio of the first apparatus in at least one of: the low power mode, or a time duration after the low power mode.

2. The first apparatus of claim 1, wherein the configuration is included in at least one of: a radio resource control message, or system information.

3. The first apparatus of claim 1 or 2, wherein the configuration comprises at least one of:the at least one target carrier,a list of candidate carriers for an idle or inactive measurement,a primary cell (PCell),a primary secondary cell (PSCell),a type of intra-frequency carrier or a type of inter-frequency carrier,the number of the at least one target carrier,an indication of retaining a carrier,at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode,a time length for retaining the measurement,a maximum number of the at least one target carrier,a minimum number of the at least one target carrier, orat least one condition for retaining the measurement in the low power mode.

4. The first apparatus of claim 3, wherein the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

5. The first apparatus of any of claims 1-4, wherein the first apparatus is caused to: select the at least one target carrier based on the configuration and a signal strength from at least one further measurement.

6. The first apparatus of any of claims 1-5, wherein the first apparatus is caused to:in accordance with a determination that the at least one target carrier is on a same band or collocated with a serving cell carrier, determine to not retain the measurement of the at least one target carrier.

7. The first apparatus of any of claims 1-6, wherein the first apparatus is caused to: receive, from the second apparatus, a trigger message for performing an idle or inactive measurement; andin response to receiving the trigger message, perform at least one measurement of the at least one target carrier by the main radio in the low power mode.

8. The first apparatus of claim 6, wherein the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

9. The first apparatus of claim 8, wherein the configuration of the idle mode measurement is based on at least one of the following conditions:a low power wake up signal (LP-WUS) entry condition,a LP-WUS exit condition,a relaxation condition, ora no-relaxation condition.

10. The first apparatus of claim 8 or 9, wherein the idle mode measurement comprises at least one of: an early measurement report, or a cell reselection measurement.

11. The first apparatus of any of claims 7-10, wherein the first apparatus is caused to: in accordance with a determination that the at least one target carrier comprises a carrier for an idle or inactive mode, determine to retain the measurement of the at least one target carrier.

12. The first apparatus of claim 11, wherein the first apparatus is further caused to: in accordance with a determination that the carrier for the idle or inactive mode comprises an early measurement report carrier, determine to retain the measurement of the early measurement report carrier based on a behavior of the first apparatus; and / orin accordance with a determination that the carrier for the idle or inactive mode comprises a cell reselection carrier, determine to retain the measurement of the cell reselection carrier.

13. The first apparatus of any of claims 1-12, wherein the first apparatus is caused to: perform the at least one measurement of the at least one target carrier based on at least one of:a low power wake up signal (LP-WUS) configuration, or low power radio (LR) configuration, being received from the second apparatus, ora paging occasion.

14. The first apparatus of any of claims 1-13, wherein a radio resource control message for releasing to an idle mode comprises a first configuration regarding the carrier selection for retaining the measurement, and system information comprises a second configuration regarding the carrier selection for retaining the measurement, the first apparatus is caused to perform one of:stopping a low power wake up signal (LP-WUS) operation and starting performing the measurement of the at least one target carrier based on one of: the first configuration or the second configuration; orcontinuing the LP-WUS operation without measuring the at least one target carrier.

15. The first apparatus of any of claims 1-14, wherein the at least one measurement of the at least one target carrier is performed based on a low power synchronization signal.

16. The first apparatus of any of claims 1-15, wherein the first apparatus is caused to: transmit a report of the measurement of the at least one target carrier to the second apparatus.

17. A second apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to:determine a configuration regarding a carrier selection for retaining a measurement of a carrier in a low power mode of a first apparatus; andtransmit, to the first apparatus, the configuration regarding the carrier selection for retaining the measurement in the low power mode.

18. The second apparatus of claim 17, wherein the configuration comprises at least one of:the at least one target carrier,a list of candidate carriers for an idle or inactive measurement,a primary cell (PCell),a primary secondary cell (PSCell),a type of intra-frequency carrier or a type of inter-frequency carrier,the number of the at least one target carrier,an indication of retaining a carrier,at least one candidate carrier measured by the main radio of the first apparatus during an idle or inactive mode,a time length for retaining the measurement,a maximum number of the at least one target carrier,a minimum number of the at least one target carrier, orat least one condition for retaining the measurement in the low power mode.

19. The second apparatus of claim 18, wherein the at least one condition for retaining the measurement comprises a first condition that a signal strength of a signal from the second apparatus is below a threshold.

20. The second apparatus of any of claims 17-19, wherein the second apparatus iscaused to: determine the configuration based on at least one of:a previous measurement report received from the first apparatus,at least one candidate carrier used by the first apparatus in a connected mode,at least one candidate carrier used in a time duration,a use of a primary secondary cell (PSCell) prior to a connection release of the first apparatus,a next best cell after a serving cell of the first apparatus,at least one candidate carrier on which the first apparatus has an active data connection in a connected mode,loads and measurement qualities of a plurality of candidate carrier, measurement qualities of a plurality of candidate intra-frequency carrier, or measurement qualities of a plurality of candidate inter-frequency carrier.

21. The second apparatus of claim 20, wherein the second apparatus is cause to:in accordance with a determination that the PSCell is used prior to the connection release, add the PSCell and a primary cell (PCell) in the configuration.

22. The second apparatus of any of claims 17-21, wherein the second apparatus is caused to:transmit, to the first apparatus, a trigger message for performing an idle or inactive measurement; and / orreceive a report of the measurement of the at least one target carrier from the first apparatus.

23. The second apparatus of claim 22, wherein the trigger message is included in at least one of: a configuration of an idle mode measurement, a low power wake up signal (LP-WUS) configuration, a low power receiver (LR) measurement configuration, or a cell reselection configuration.

24. The second apparatus of claim 23, wherein the configuration of an idle mode measurement is based on at least one of the following conditions:a low power wake up signal (LP-WUS) entry condition,a LP-WUS exit condition,a relaxation condition, ora no-relaxation condition.

25. The second apparatus of claim 23 or 24, wherein the idle mode measurement comprises at least one of: an early measurement report, or a cell reselection measurement.5

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