Method and wireless communication device for saving power using additional reference symbols in idle mode

Abstract

A wireless communication device (130) includes a receiving module (910), a transmitting module (920), and a processor (960). The processor (960) includes a determining module (930) and a processing module (940). The wireless communication device is arranged to perform a method for saving power in a wireless communication system. In the wireless communication system, transmissions of a first set of reference symbols (RS) and a second set of RS are provided. The method includes obtaining (210) information about the transmission of the second set of RS, and determining (220) which RS to use for an idle mode task based on the obtained information about the transmission of the second set of RS. The first set of RS is provided periodically, while the second set of RS is provided in any one of periodic, semi-persistent, or aperiodic transmissions.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a user equipment and a method for saving power therein. The embodiments particularly relate to how to use additional reference symbols to perform idle mode tasks in a wireless communication system. Background Art

[0002] The Universal Mobile Telecommunications System (UMTS) is a third-generation (3G) communication network evolved from the second-generation (2G) Global System for Mobile Communications (GSM). The specifications of the Evolved Packet System (EPS), which is also referred to as the fourth-generation (4G) network or Long-Term Evolution (LTE), have been completed in the Third Generation Partnership Project (3GPP) and continue to be used in upcoming 3GPP releases for, e.g., specifying the fifth-generation (5G) New Radio (NR) network.

[0003] 3GPP is defining the technical specifications of 5G NR. In Release 15 (Rel-15) NR, a user equipment (UE) can be configured with up to four carrier bandwidth parts (BWPs) in the downlink, where a single downlink carrier bandwidth part is active at a given time. The UE can be configured with up to four carrier bandwidth parts in the uplink, where a single uplink carrier bandwidth part is active at a given time. If the UE is configured with a supplementary uplink, the UE can be additionally configured with up to four carrier bandwidth parts in the supplementary uplink, where a single supplementary uplink carrier bandwidth part is active at a given time.

[0004] For a carrier bandwidth part with a given numerology μ i a set of consecutive physical resource blocks (PRBs) is defined and numbered from 0 to where i is the index of the carrier bandwidth part. A resource block (RB) is defined as 12 consecutive subcarriers in the frequency domain.

[0005] NR supports multiple orthogonal frequency division multiplexing (OFDM) numerologies μ as shown in Table 1, where the subcarrier spacing Δf and the cyclic prefix of the carrier bandwidth part are configured by different higher layer parameters for the downlink (DL) and uplink (UL) respectively.

[0006] Table 1: Supported Transmission Numerologies

[0007]

[0008]

[0009] Physical Channels

[0010] The downlink physical channels correspond to a set of resource elements that carry information originating from higher layers. The following downlink physical channels are defined:

[0011] · Physical Downlink Shared Channel, PDSCH

[0012] · Physical Broadcast Channel, PBCH

[0013] · Physical Downlink Control Channel, PDCCH

[0014] The PDSCH is the main physical channel for unicast downlink data transmission, but it is also used to transmit random access responses (RARs), certain system information blocks, and paging information. The PBCH carries the basic system information required for the UE to access the network. The PDCCH is used to transmit downlink control information (DCI) required for PDSCH reception, mainly scheduling decisions, and uplink scheduling grants for enabling transmission on the PUSCH.

[0015] The uplink physical channels correspond to a set of resource elements that carry information originating from higher layers. The following uplink physical channels are defined:

[0016] · Physical Uplink Shared Channel (PUSCH)

[0017] · Physical Uplink Control Channel (PUCCH)

[0018] · Physical Random Access Channel (PRACH)

[0019] The PUSCH is the uplink counterpart of the PDSCH. The UE uses the PUCCH to transmit uplink control information, including hybrid automatic repeat request (HARQ) acknowledgments, channel state information reports, etc. The PRACH is used for random access preamble transmission.

[0020] NR Reference Signals

[0021] The ultra-lean design principles in NR aim to minimize always-on transmissions that existed in earlier systems, such as LTE cell-specific reference signal (CRS) reference signals. In contrast, NR periodically provides reference signals such as synchronization signal blocks (SSBs), for example, once every 20 milliseconds by default. In addition, for UEs in connected mode, a set of reference signals is typically provided to achieve optimal link performance. Some of these reference signals will be described below.

[0022] Channel State Information Reference Signal for Tracking (CSI-RS)

[0023] A UE expected to be in the Radio Resource Control (RRC) connected mode receives from the network (NW) an RRC layer UE-specific configuration with an NZP-CSI-RS-ResourceSet message, where the NZP-CSI-RS-ResourceSet message is configured to include the parameter trs-Info. For an NZP-CSI-RS-ResourceSet configured with a higher layer parameter trs-Info set to "true", the UE shall assume that the antenna ports with the same port index of the configured non-zero power (NZP) CSI-RS resources in the NZP-CSI-RS-ResourceSet are also the same.

[0024] - For frequency range 1 (FR1), the UE may be configured with one or more NZP CSI-RS sets, where an NZP-CSI-RS-ResourceSet consists of four periodic NZP CSI-RS resources in two consecutive time slots, and where there are two periodic NZP CSI-RS resources in each time slot. If no two consecutive time slots are indicated as downlink time slots by the tdd-UL-DL-ConfigurationCommon message or the tdd-UL-DL-ConfigDedicated message, the UE may be configured with one or more NZP CSI-RS sets, where an NZP-CSI-RS-ResourceSet consists of two periodic NZP CSI-RS resources in one time slot.

[0025] - For frequency range 2 (FR2), the UE may be configured with one or more NZP CSI-RS sets, where an NZP-CSI-RS-ResourceSet consists of two periodic CSI-RS resources in one time slot, or an NZP-CSI-RS-ResourceSet consists of four periodic NZP CSI-RS resources in two consecutive time slots, where there are two periodic NZP CSI-RS resources in each time slot.

[0026] A UE with an NZP-CSI-RS-ResourceSet configured with a higher layer parameter trs-Info may configure the CSI-RS resources as:

[0027] - Periodic, where the CSI-RS resources in the NZP-CSI-RS-ResourceSet are configured with the same periodicity, bandwidth, and subcarrier position.

[0028] - A set of periodic CSI-RS resources and a second set of aperiodic CSI-RS resources, where the aperiodic CSI-RS resources and the periodic CSI-RS resources have the same bandwidth with the same RB positions, and the aperiodic CSI-RS is "QCL-Type-A" and "QCL-Type-D" of the periodic CSI-RS resources when applicable. For frequency range 2, the UE does not expect the scheduling offset between the last symbol of the PDCCH carrying the triggering DCI and the first symbol of the aperiodic CSI-RS resources to be less than the ThresholdSched-Offset reported by the UE. The UE shall expect that both the periodic CSI-RS resource set and the aperiodic CSI-RS resource set are configured with the same number of CSI-RS resources and the same number of CSI-RS resources in one time slot. For the aperiodic CSI-RS resource set, if triggered, and if the associated periodic CSI-RS resource set is configured with four periodic CSI-RS resources in two consecutive time slots, with two periodic CSI-RS resources in each time slot, the higher layer parameter aperiodicTriggeringOffset indicates the triggering offset with respect to the first time slot of the first two CSI-RS resources in the set.

[0029] The UE does not expect to be configured with a CSI-ReportConfig associated with a CSI-ResourceConfig that contains an NZP-CSI-RS-ResourceSet (which is configured with trs-Info) and a CSI-ReportConfig with a higher layer parameter timeRestrictionForChannelMeasurements set to "configured".

[0030] The UE does not expect to be configured with a CSI-ReportConfig with a higher layer parameter reportQuantity, which is not set to "none" for an aperiodic NZP CSI-RS resource set configured with trs-Info.

[0031] The UE does not expect to be configured with a CSI-ReportConfig for a periodic NZP CSI-RS resource set (which is configured with trs-Info).

[0032] The UE does not expect to be configured with an NZP-CSI-RS-ResourceSet that is configured with both trs-Info and repetition.

[0033] Each CSI-RS resource defined in clause 7.4.1.5.3 of [4, TS 38.211] is configured by the higher layer parameter NZP-CSI-RS-Resource, with the following restrictions:

[0034] - The time domain positions of two CSI-RS resources in one slot, or the time domain positions of four CSI-RS resources in two consecutive slots, which are the same in two consecutive slots, as defined by the higher layer parameter CSI-RS-resourceMapping, which is given by one of the following:

[0035] - For frequency range 1 and frequency range 2, l ∈ {4, 8}, l ∈ {5, 9}, or l ∈ {6, 10},

[0036] - For frequency range 2, l ∈ {0, 4}, l ∈ {1, 5}, l ∈ {2, 6}, l ∈ {3, 7}, l ∈ {7, 11}, l ∈ {8, 12}, or l ∈ {9, 13}.

[0037] - The single-port CSI-RS resource with density ρ = 3 is given by Table 7.4.1.5.3-1 in [4, TS 38.211], and the higher layer parameter density is configured by CSI-RS-ResourceMapping.

[0038] - The bandwidth of the CSI-RS resource, given by the higher layer parameter freqBand configured by CSI-RS-ResourceMapping, is the minimum of 52 and number of resource blocks, or equal to number of resource blocks. For operation in shared spectrum channel access, freqBand configured by CSI-RS-ResourceMapping is the minimum of 48 and number of resource blocks, or equal to number of resource blocks.

[0039] - If the bandwidth of the CSI-RS resource is greater than 52 resource blocks, the UE is not expected to be configured with a 2 μ ×10 slot period.

[0040] - The periodicity and slot offset of the periodic NZP CSI-RS resource, given by the higher layer parameter periodityAndOffset configured by NZP-CSI-RS-Resource, is one of 2 μ X p slots, where x p = 10, 20, 40, or 80, and where μ is defined in clause 4.3 of [4, TS 38.211].

[0041] - The same powerControlOffset and powerControlOffsetSS given by the NZP-CSI-RS-Resource value across all resources.

[0042] NZP CSI-RS

[0043] The UE may be configured with one or more NZP CSI-RS resource set configurations and NZP-CSI-RS-ResourceSet as indicated by the higher layer parameter CSI-ResourceConfig. Each NZP CSI-RS resource set consists of K ≥ 1 NZP CSI-RS resources.

[0044] The UE shall configure parameters assumed to be non-zero transmission power for CSI-RS resources via the higher layer parameter NZP-CSI-RS-Resource. The CSI-ResourceConfig and NZP-CSI-RS-ResourceSet for each CSI-RS resource configuration may refer to [4, TS 38.211].

[0045] All CSI-RS resources within a set, except for those NZP CSI-RS resources used for interference measurement, are configured with the same density and the same number of CSI-RS ports.

[0046] The UE expects that all CSI-RS resources within a resource set are configured with the same starting RB and number of RBs, as well as the same code division multiplexing (CDM) value and pattern.

[0047] The bandwidth and the initial common resource block (CRB) index of the CSI-RS resources within the BWP, as defined in clause 7.4.1.5 of [4, TS 38.211], are determined respectively based on the higher layer parameters nrofRBs and startingRB within the CSI-FrequencyOccupation IE configured by the higher layer parameter freqBand within the CSI-RS-ResourceMapping IE. Both nrofRBs and startingRB are configured as integer multiples of 4 RBs, and the reference point of startingRB is CRB0 on the common resource block grid. If then the UE shall assume the initial CRB index of the CSI-RS resource to be otherwise N initial RB = startingRB. If then the UE shall assume the bandwidth of the CSI-RS resource to be otherwise In all cases, the UE shall expect

[0048] The following is a brief description of some IE parameters. For detailed information, see TS 38.214.

[0049] The IE NZP-CSI-RS-Resource is used to configure the non-zero power (NZP) CSI-RS transmitted in the cell including the IE, and the UE can be configured to measure it.

[0050] The IE NZP-CSI-RS-ResourceId is used to identify an NZP-CSI-RS-Resource.

[0051] The IE NZP-CSI-RS-ResourceSet is a set of non-zero power (NZP) CSI-RS resources (their IDs) and parameters for the set.

[0052] The IE NZP-CSI-RS-ResourceSetId is used to identify an NZP-CSI-RS-ResourceSet.

[0053] The IE CSI-ResourceConfig defines a set of one or more NZP-CSI-RS-ResourceSet, CSI-IM-ResourceSet, and / or CSI-SSB-ResourceSet.

[0054] The IE CSI-ResourceConfigId is used to identify a CSI-ResourceConfig.

[0055] The IE CSI-ResourcePeriodicityAndOffset is used to configure the period, and the corresponding offset of the periodic and semi-persistent CSI resources, and is used for periodic reporting and semi-persistent reporting on the PUCCH. Both the period and the offset are given in terms of the number of slots. The period value slot4 corresponds to 4 slots, slots5 corresponds to 5 slots, and so on.

[0056] The IE CSI-RS-ResourceConfigMobility is used to configure CSI-RS-based RRM measurements.

[0057] The IE CSI-RS-ResourceMapping is used to configure the resource element mapping of the CSI-RS resource in the time domain and the frequency domain.

[0058] In NR in the connected mode, the UE is provided with periodic or semi-periodic or aperiodic CSI-RS / TRS, i.e., tracking reference signals or CSI RS for tracking, so that the UE can measure the channel quality and / or track the reference signals to fine-tune its time and frequency synchronization. This mechanism is only for the RRC_Connected mode. The UE needs to rely on SSB measurements during the RRC_Idle or Inactive mode for functions such as automatic gain control (AGC) and synchronization and other functions. The default operation is for the UE to wake up at least two SSBs before the paging occasion (PO), perform AGC at the first SSB, perform automatic frequency control (AFC) and time synchronization at the second SSB, and then monitor the PO.

[0059] The problem with relying on SSBs is that the time intervals of SSBs are relatively long, e.g., 20 milliseconds. Sometimes the UE may need to exit deep sleep for a long total time to read its paging message, for example, after previously receiving an available SSB, which will also cause waste of UE power. Summary of the Invention

[0060] Therefore, a method is needed that can enable the UE to save power in the idle mode.

[0061] As described above, in addition to SSBs, there are other additional RSs or non-SSB RSs, such as CSI-RS / TRS, and the UE is not aware of the potential existence of such RSs during the RRC_Idle or Inactive mode. If the UE can continue to utilize potential CSI-RS / TRS or other non-SSB RSs to perform the required idle mode tasks during the idle or inactive mode, reducing the number of SSB instances to be received in the middle, then it can remain in deep sleep for a longer time and thereby achieve higher power savings.

[0062] According to one aspect of the embodiments herein, the above object is achieved by a method for power saving in a wireless communication system executed in a UE. In the wireless communication system, transmissions of a first set of reference signals (RSs) (e.g., SSBs) and a second set of RSs (i.e., non-SSB RSs such as CSI-RS / TRS) are provided. The UE obtains information about the transmission of the second set of RSs and determines which RS to use for idle mode tasks based on the obtained information about the transmission of the second set of RSs.

[0063] During the RRC_Idle or Inactive mode, the UE can obtain information about the second set of RSs (i.e., non-SSB RSs) by learning or being directly notified by the NW node. When the UE obtains this information, the embodiments herein propose how to utilize the additional RSs, especially for the purpose of power saving.

[0064] Embodiments of the present disclosure provide some methods and mechanisms. Through these methods and mechanisms, the UE first learns that even when the UE is in the RRC_Idle or Inactive mode, the network node continues to transmit non-SSB RSs (such as CSI-RS / TRS). Secondly, the UE also learns the mode of potential additional RSs other than SSB during the RRC_Idle or Inactive mode. Finally, based on which RS is closer to the PO, the UE decides to wake up and perform relevant measurements.

[0065] Embodiments of the present disclosure also provide several methods and mechanisms. Through these methods and mechanisms, the UE can utilize the presence of non-SSB RSs to save power. The methods are as follows:

[0066] For example, by considering the chronological order of occurrence of relevant SSBs, TRSs, and / or PO positions, or by comparing the total energy consumption of the baseline and alternative (i.e., non-SSB RS-assisted) action sequences, it is determined whether the available non-SSB RSs can be advantageously used. The baseline is that the UE only uses SSBs for AGC and AFC without the assistance of non-SSB RSs. The alternative is that the UE relies on the assistance of non-SSB RSs other than SSBs to perform AGC and AFC, where the SSB and non-SSB can have different time sequences.

[0067] Determine which RS combination (such as SSB, non-SSB, or a combination of both) can be used for the required idle mode tasks.

[0068] In particular, depending on how the information about the presence of non-SSB RSs is obtained and whether the presence is ensured or has a relevant specific probability, the methods performed in the UE can be divided into the following aspects:

[0069] Aspect 1: Methods for the UE to utilize non-SSB RSs during RRC_Idle / Inactive when the presence of non-SSB RSs is ensured.

[0070] Aspect 2: Methods for the UE to utilize non-SSB RSs during RRC_Idle / Inactive when the presence of non-SSB RSs is associated with a probability.

[0071] The proposed solution provides a mechanism for the UE to learn the configuration of additional RSs in the RRC connected state, enabling it to learn the presence and mode of potential additional RSs other than SSBs during the RRC_Idle or Inactive mode, and then using this information to enable longer deep sleep phases to achieve more power savings.

[0072] The proposed solution also provides a mechanism for the UE to utilize the information of non-SSB RS during the RRC_Idle or Inactive mode to perform the required idle mode tasks, in order to achieve lower power consumption.

[0073] Therefore, the embodiments of this document provide a method for the UE to save power by utilizing additional RS provided in a wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Exemplary embodiments of this document will be described in more detail with reference to the accompanying drawings, in which:

[0075] Figure 1 A wireless communication system in which the embodiments of this document can be implemented is shown;

[0076] Figure 2 Is a flowchart showing the method performed in the UE according to the embodiments of this document;

[0077] Figure 3 An example scenario showing the reference symbol positions is shown;

[0078] Figure 4 Another example scenario showing the reference symbol positions is shown;

[0079] Figure 5 Another example scenario showing the reference symbol positions is shown;

[0080] Figure 6 Another example scenario showing the reference symbol positions is shown;

[0081] Figure 7 Another example scenario showing the reference symbol positions is shown;

[0082] Figure 8 Another example scenario showing the reference symbol positions is shown; and

[0083] Figure 9 Is a schematic block diagram illustrating an embodiment of the UE. DETAILED DESCRIPTION

[0084] Figure 1 Is a schematic overview diagram depicting a wireless communication system 100 in which the embodiments of this document can be implemented. The wireless communication system 100 can include any wireless system or cellular network, such as a Long-Term Evolution (LTE) network, any 3rd Generation Partnership Project (3GPP) cellular network, a Fourth Generation (4G) network, a Fifth Generation (5G) or NR network, etc.

[0085] In a wireless communication system 100, a wireless communication device, such as a user equipment 130 (such as a mobile station or terminal, wireless terminal), communicates with one or more core networks (CNs) via one or more radio access technologies (such as RAT 1, RAT2). Those skilled in the art should understand that the term "wireless communication device" is a non-limiting term, which means any terminal, wireless communication terminal, user equipment, machine type communication (MTC) device, Internet of Things device, device-to-device (D2D) terminal or node, such as a smart phone, laptop, mobile phone, sensor, relay device, mobile tablet or even a small base station communicating within a cell. The terms "user equipment", "UE" and "wireless communication device" may be used interchangeably herein.

[0086] Network nodes, such as a first network node 110 and a second network node 120, operate in a wireless communication network. The first network node 110 provides radio coverage over a geographical area, cell area or service area 111, which may also be referred to as a beam or a set of beams covering the service area of a first radio access technology RAT 1 (such as 5G, LTE, LTE-M, Wi-Fi or the like). The second network node 120 provides radio coverage over a geographical area, service area 121, which may also be referred to as a beam or a set of beams covering the service area of a second radio access technology RAT 2 (such as 5G, LTE, LTE-M, Wi-Fi or the like). The service areas 611 and 621 for, for example, LTE and NR may overlap in some areas. The first network node 110 and the second network node 120 may be referred to as eNB, gNB, etc.

[0087] In the RRC_Connected state, in addition to SSB, the UE 130 is typically also configured with a set of additional non-SSB reference signals (RSs) for optimizing link operation, such as TRS or CSI-RS. The term "non-SSB RS" here may refer to CSI-RS or TRS, but may also be other RS types. This usage refers to providing RS configuration by the gNB, measurements performed by the UE on these RSs and / or receiver tuning, and conditionally reporting measurements to be performed by the UE to the gNB based on the configuration provided by a separate gNB to have a mutual understanding of the link quality. However, if the UE transitions to RRC_Idle / Inactive, the NW node may choose not to turn off the non-SSB RS. In the context of this application, from the perspective of the UE, information about the presence of non-SSB RSs is either explicitly provided by the NW node and thus ensured in specific time / frequency (T / F) resources, or must be detected or learned by the UE itself, and thus the latter is probability-related.

[0088] The UE has two alternative ways to detect or learn the presence information about the RSs other than SSBs.

[0089] Alternative 1: The UE learns the gNB behavior regarding the RSs other than SSBs during RRC_Connected.

[0090] During RRC_Connected, the NW node can provide the RSs other than SSBs to the UE periodically, semi-persistently, or aperiodically. In all cases, the NW node then provides information about the RS characteristics, such as scrambling code, comb / interleaving and symbol pattern, quasi-co-location (QCL) information (e.g., relationship with other beams), antenna port configuration, power offset, etc. To let the UE know when and where the RSs appear in the time / frequency (T / F) resources, the UE also obtains the provisioning schedule for the periodic and semi-persistent RSs during its connected mode operation.

[0091] For aperiodic RSs, the RSs can be provided in any T / F resources according to the instantaneous NW node preference, whereby the UE is notified in the upcoming downlink control information (DCI). Therefore, in general, the UE does not know the provisioning schedule in advance. This method enables the NW node to flexibly adapt the provisioning according to specific requirements further illustrated below.

[0092] In one embodiment, the UE learns that even if the NW node has chosen to adopt an aperiodic configuration method for some RSs, the NW node still follows a specific pattern when providing the RSs. That is, the RSs associated with the CSI report requests sorted by the NW appear in a periodic manner.

[0093] In a related embodiment, the UE learns that the aperiodic RS triggering, such as CSI-RS triggering, occurs periodically according to a specific period or according to other T / F parameters. For example, the NW node triggers the UE to report L1_RSRP every 80 milliseconds, or triggers the CSI-RS report every 40 milliseconds. The UE can also learn that the frequency position remains unchanged or changes according to a consistent pattern. For example, the CSI-RS is aperiodic, but it appears periodically within a T / F window.

[0094] In yet another embodiment, the UE learns that the provisioning schedule and RS characteristics of a certain RS are associated with the UE behavior. For example, the UE can detect that the RSs are provided, and the NW node frequently (e.g., every 40 milliseconds) requests reports according to a dense RS configuration, such as the number of symbols, interleaving pattern, etc., while when the UE is moving at high speed (e.g., above a certain threshold), requests reports less frequently (e.g., every 80 milliseconds) according to a sparse configuration.

[0095] In another embodiment, the UE learns the specific NW node behavior regarding RS in a specific cell, specific beam, BWP, FR range, etc. For example, the NW node may behave the same or differently in different cells, beams, beam groups (e.g., regarding wide beams), BWPs, or FR ranges. For example, in FRI, RS may not be as frequent as in FR2, or vice versa. Or, in one cell, RS may occur with the same T / F as in another cell, or in a slightly modified form, or according to a completely different pattern. The UE can then learn the patterns for different frequency ranges separately. Then, the UE stores information about the configuration scheduling (T / F) and RS parameter configuration for different cells / BWPs, etc. The UE can also observe that even though they may seem different, the RS configuration parameters may follow a specific pattern. For example, the scrambling seed configuration used for RS in different cells is based on the cell identifier.

[0096] Alternative 2: The UE learns whether non-SSB RS is available during RRC_Idle / Inactive

[0097] The objective in this regard is that even though the configuration of Alternative 1 above is specifically provided for UEs in the RRC_Connected mode, it is still beneficial for UEs in the RRC_Idle / Inactive mode to use or enjoy the presence of these RSs because they may be sent by the NW node anyway.

[0098] In one embodiment, the UE can learn whether there is periodic or semi-persistent non-SSB RS while the UE is in RRC_Idle / Inactive. For simplicity, the term RRC_Idle / Inactive will be abbreviated as "idle" from hereon. For example, the UE can wake up from idle assuming the presence of RS to check whether they exist. For this purpose, the UE can apply different detection techniques. For example, the UE can correlate the received signal with the expected RS pattern in the time domain or frequency domain to verify whether it contains RS or no signal. For example, if the correlation result is higher than a specific threshold, the UE can note that this is an RS; otherwise, the UE will assume that there is no RS signal during idle time.

[0099] In one embodiment of the present invention, the UE can be associated with several hypothetical sequences, such as: comb-like / interleaved patterns, symbol density, etc. The UE can further utilize the knowledge outlined in Alternative 1 to obtain the most likely RS reference sequence correlation. The UE can, for example, assume that it may be on a high-speed train together with other connected UEs equipped with RSs in high-speed mode and associate with the sequences typically configured for such a scenario, based on its UE speed or based on specific information, such as the access points (e.g., WiFi) of any detected technology. Additionally, the UE can utilize this information and assume the periodicity of the RS based on this information. Such information is not only based on speed but also on time and / or location. For example, the UE may have learned earlier that in areas with heavy traffic, the RS is provided at a higher periodic rate.

[0100] For the detector itself, instead of waking up the entire receiver, the UE can also use a lower-power receiver to wake up at the time when the expected non-SSB RS is expected to appear, so as to detect the presence or absence of the relevant RS. Additionally, the UE can use previous SSB or non-SSB RS measurements to calibrate the detector.

[0101] The UE can further decide to perform this process one or more times during idle time, or perform the same process in different cells, BWPs, beams, or FR ranges. For example, the UE may notice that non-SSB RSs (e.g., TRS) exist in one cell but not in another during idle time, or they exist in FR2 but not in FR1, and vice versa, etc.

[0102] According to some embodiments herein, the UE can perform this process more frequently in a specific cell and / or at certain times of the day. For example, the NW node may only provide such RSs when there are UEs in the RRC_Connected state, otherwise not. Therefore, a UE in the idle state can learn that the probability of the RS being provided is higher in certain situations (e.g., busy times) or cells (e.g., busy locations) compared to other situations.

[0103] In another embodiment, the UE may apply the procedures described for the detection of non-SSB RS during the idle time of periodic or semi-persistent RS to aperiodic RS, as learned in Aspect 1. For example, in a T / F component where the UE expects the aperiodic RS to appear following a pattern known in Aspect 1, the UE may wake up the main receiver or a low-power receiver with a low-power detector during the idle time. Additionally, as in the case of periodic or semi-persistent RS, even if a given UE has exited the connected mode, the UE may learn whether non-SSB RS still exists during the idle time of aperiodic RS in a particular cell, BWP, beam, FR band, etc. For example, the aperiodic RS may exist during the idle time of FR2 but not during the idle time of FR1, or vice versa, or it may exist in both, or they may exist in one cell but not in another, or they may exist in all cells, etc.

[0104] In the above example, the UE may further learn which specific RS exist during the idle time. For example, the UE may learn that TRS exists but CSI-RS generally does not, or that they all exist, or that a subset of them exists.

[0105] In an extension of Alternative 2, the UE may test for the presence of non-SSB RS in the idle mode, even if it has not obtained or learned the configuration information of the RS in the connected mode in a given cell. This method may be used if the UE is mobile and changes its resident cell such that the current resident cell is no longer the UE's previous connected-mode cell. In this case, the UE utilizes the information obtained in Alternative 1, such as information about the scrambling sequence that is assumed to be used for the new cell in the case where the scrambling sequence is based on the cell identity. In one embodiment, the UE may attempt to detect the presence of RS and the transmission mode in the T / F location, and / or detect according to the scrambling and other resource set parameters or parameter combinations that were valid in its previous serving cell. If the previous serving cell had multiple different RS configurations, the UE may attempt to detect according to multiple or all of the previously encountered patterns. In another embodiment, the UE may use the code information from the previous serving cell but attempt to detect within a wider range of T / F resource sets (e.g., in multiple or all time slots with a given number of symbols). The UE may perform energy detection to identify the symbols that may be transmitting RS and attempt to perform correlation detection in the symbols whose energy level or detected energy pattern matches the expected RS energy or pattern.

[0106] According to an embodiment of the present disclosure, the above two aspects are distinguished, i.e., the information about the presence of non-SSB RSs is either explicitly provided by the NW node and thus guaranteed in specific time / frequency (T / F) resources, or it must be detected or learned by the UE itself. A mechanism is provided that enables the UE to save power in various aspects by utilizing non-SSB RSs during the RRC_Idle / Inactive mode.

[0107] Hereinafter, the terms "NW", "network node", "base station", and "gNB" are used interchangeably. In addition, when it is mentioned that the UE is in the idle mode, it means that the UE is in the RRC_Idle or Inactive state. Additionally, for simplicity, the exemplary embodiments focus on using the tracking reference signal (TRS) as a specific non-SSB RS. However, the same concepts and mechanisms can of course be extended to other non-SSB RSs, such as CSI-RS.

[0108] Next, exemplary embodiments of the UE using the presence of non-SSB RSs to save power are described.

[0109] In one embodiment, after confirming the presence of non-SSB RSs or a subset thereof (e.g., TRS) during idle time, the UE can utilize this information to optimize its different processes, such as AGC, T / F synchronization, etc. In particular, the UE can use this information to achieve power savings.

[0110] In one example, the UE may notice that non-SSB RSs, such as TRS, are closer to the PO than SSBs, so it can decide to skip SSB measurements and directly wake up and measure the TRS before the PO, e.g., for rough T / F synchronization. In this way, the UE can sleep deeply for a longer time, thus achieving higher power savings.

[0111] In another example, the UE may notice that a TRS is closer to one SSB and farther from another SSB. Assuming the TRS is between SSB1 and SSB2, and SSB2 is the SSB closest to the PO, the UE can skip SSB1 and wake up at the TRS before SSB2 for AGC to perform measurements instead of waking up at SSB1 for AGC. Similarly, the UE can sleep for a longer time, thus achieving higher power savings or consuming less energy. In a related example, the TRS occasion can be after SSB2, and in this case, the UE can decide to skip SSB1 for AGC based on the probability that the TRS appears after SSB1. For example, if the probability is high or higher than a threshold, the UE skips SSB1 for AGC, performs AGC at SSB2, and performs AFC at the TRS. In the worst case, if there is no TRS, in the next PO, it only relies on the SSB. However, if the probability is not high enough (e.g., lower than a threshold), the UE can only rely on the SSB.

[0112] In another embodiment, especially when the RS other than SSB consists of multiple time slots, such as a TRS with two consecutive time slots, if there is enough time between the time slots for reliable AGC / AFC, the UE can decide to perform both AGC and AFC on the same TRS and then skip all SSBs. Again, for robustness, the UE can decide to select a TRS before or after the latest SSB before the PO based on the probability of the existence of the TRS.

[0113] In another embodiment, the UE can decide to directly use the detection result in Option 2. That is, if the detection result indicates the existence of an RS other than SSB in a specific T / F component, the UE can decide to directly measure this RS and skip the current SSB measurement. In a related implementation, the UE can first use a low-power detector to detect the RS other than SSB, and then use a full receiver when additional operations (such as synchronization, etc.) are required.

[0114] The following will refer to Figure 2 to describe a method for power saving performed in UE 130 according to an embodiment herein in a wireless communication system 100. In the wireless communication system 100, transmissions of a first set of reference symbols (RSs) (such as SSBs) and a second set of RSs (such as RSs other than SSBs like TRSs, CSI-RSs, etc.) are provided. The method includes the following actions:

[0115] Action 210

[0116] UE 130 obtains information about the transmission of the second set of RSs;

[0117] Action 220

[0118] The UE 130 determines which RS to use for idle mode tasks based on the obtained information about the transmission of the second set of RSs.

[0119] The idle mode tasks may be AGC, AFC, timing drift correction, etc.

[0120] According to how the UE obtains the information about the transmission of the second set of RSs, the method for power saving performed in the UE 130 according to the embodiments herein is described in the following two aspects.

[0121] Aspect 1: The UE uses the ensured non-SSB RSs during the idle mode to save power.

[0122] According to some embodiments, the UE receives the information about the transmission of the second set of RSs from a network node. Here, it is assumed that the NW node has provided the UE with the information about the resources where the second set of RSs (e.g., TRS) exists during the idle mode, and the explicit or implicit information that the second set of RSs (e.g., TRS) will be available within a certain time interval in the future. The configuration information may include T / F position, resource element (RE) pattern in the symbol, period, code sequence, related transmission configuration indication (TCI) state, etc., in short, all the parameters required for the UE to detect, measure, or utilize the second set of RSs (e.g., TRS) signals. Therefore, the UE has accurate information about the existence of the second set of RSs (e.g., TRS) in the idle mode.

[0123] In one class of embodiments, the UE may determine whether and how to utilize the second set of RSs (e.g., TRS) based on the time sequence of the appearance of the first set of RSs and the second set of RSs and / or the paging occasion (PO) position - such as the time sequence of the appearance of SSB and TRS and the paging PDCCH signal near the PO.

[0124] According to some embodiments, the UE may determine the sleep mode based on the time sequence of the appearance of the first set of RSs and the second set of RSs.

[0125] In one embodiment, the TRS is located between two SSBs, namely SSB occasion x (hereinafter referred to as SSB_x), and SSB occasion x + 1 (hereinafter referred to as SSB_x+1), as Figure 3As shown, where SSB_x+1 is closest to the paging occasion (PO) of the UE. In this case, the UE can decide to use the TRS for AGC and SSB_x+1 for AFC, thereby skipping SSB_x and staying in the radio deep sleep state for a longer time before waking up for TRS measurement. Additionally, depending on the amount of available time between the TRS and SSB_x+1 or between SSB_x+1 and the PO, the UE can decide to select an appropriate sleep mode, such as light sleep or micro sleep. It should be noted that paging is just an example. The PO can be any type of UE activity that requires the UE to have an appropriate reception level (i.e., AGC is needed) and to be synchronized with the network node in terms of frequency and occasion (i.e., AFC is needed). Other examples can be broadcast or multicast channel reception, PRACH transmission, etc.

[0126] As Figure 4 shown, in another embodiment, among the available reference symbols, the TRS may be closest to the PO. At this time, the UE can skip SSB_x again, but wake up at SSB_x+1 to perform AGC, and then use the TRS for AFC. Similarly, in this case, the UE can stay in deep sleep for a longer time by skipping SSB_x, and then select a suitable power-saving mode according to the available time between SSB_x+1 and the TRS and between the TRS and the PO.

[0127] As Figure 5 shown, in another embodiment, the UE may have the following occurrence order: SSB_x, TRS_x, SSB_x+1, TRS_x+1, PO. In this case, if the distance between SSB_x+1 and TRS_x+1 is far enough for continuous AGC and AFC, in addition to SSB_x, the UE can also skip TRS_x, thereby staying in deep sleep for a longer time before waking up for the measurement or processing of SSB_x+1 and TRS_x+1.

[0128] As Figure 6 shown, in another embodiment, the occurrence order may be: SSB_x, SSB_x+1, TRS_x, TRS_x+1. Therefore, if TRS_x and TRS_x+1 are far enough apart in time to perform AGC / AFC operations, the UE can skip both SSB_x and SSB_x+1.

[0129] In another embodiment, if the TRS consists of two time slots and the duration of the time slots is long enough for reliable AGC and AFC operations, the UE can skip all other SSBs and TRSs and use the same TRS for both AGC and AFC associated with one time slot respectively. In this case, the TRS closest to the PO can be used to make the UE stay in deep sleep for a longer time. This is inFigure 7 is described in

[0130] In another embodiment, since one TRS time slot contains 2 TRS symbols and has a fixed inter-symbol distance of 4, the UE can use the first symbol for AGC and the second symbol for AFC. Therefore, in Figure 3 and Figure 4 the SSB reception can be skipped.

[0131] In Figure 3 and Figure 4 shown in another embodiment, the UE can perform AGC and coarse time / frequency synchronization by receiving the SSB, and use the TRS to perform finer time / frequency correction.

[0132] Generally, the signal or signal component used for AGC tuning can also be used for link quality assessment, such as serving cell reference signal received power (RSRP) or signal-to-interference-plus-noise ratio (SINR). The measurement result can be determined as the scaled output of a correlator, which is determined as the magnitude of the inner product of the received RE content and a reference sequence based on the TRS or SSS content. In embodiments where the TRS is used for measurement purposes, the measurement result based on the TRS must be consistent with the conventional measurement result based on the SSB (e.g., based on the secondary synchronization signal (SSS)) used for comparison with the SSB quality values of other cells; the raw measurements are usually inconsistent because the TRS and SSS have different numbers of REs and may have different power boosts applied by the gNB. The UE can adopt one of the following methods to achieve proper scaling:

[0133] · Perform measurements on the serving cell of the UE based on the SSB (e.g., SSS) and the TRS, and determine a scaling factor as the ratio of the two. The ratio can be determined using the measurement result of the two signals at one time or the average of the measurement results of the two signals within the same time interval. After that, scale the power estimate based on the TRS by multiplying by the scaling factor.

[0134] · Estimate the relative power values of the REs of the TRS and the REs of the SSS during one or more measurements, and determine the number of REs used to estimate the power of the two signals. Then, scale the power estimate based on the TRS by multiplying by the ratio of "the number of REs of the SSB multiplied by the power of the REs of the SSB" and "the number of REs of the TRS multiplied by the power of the REs of the TRS".

[0135] Then the UE uses the scaled power estimate to compare with the link quality estimates of other cells.

[0136] According to some embodiments herein, the UE may determine the RS utilization sequence for the idle mode task by comparing the total energy consumption of the utilization sequences of the first set of RSs and the second set of RSs.

[0137] The examples of TRS utilization introduced above mainly consider the time order of available signals. In more general embodiments, the UE also uses detailed inter-signal distance information to predict sleep opportunities, including selecting the best available sleep mode and considering the transition intervals between the sleep state and the non-sleep state. The UE may determine whether the available non-SSB RSs can be used advantageously by comparing the total energy consumption of the baseline and alternative (e.g., non-SSB RS-assisted) action sequences. The total energy estimate may include all estimated sleep, transition, and active phases for a given candidate RS utilization sequence. Multiple candidate sequences may be analyzed and the sequence with the least total energy metric may be selected. For example, as Figure 8 shown, SSB_x and TRS may be very close to each other and also close enough to the PO, such that it can be assumed that the AGC / AFC valuations of both are valid at the PO, making it more beneficial to perform AGC / AFC on SSB_x / TRS compared to the RS closest to the PO (i.e., TRS, SSB_x+1). The reason is that the UE can enjoy a longer total sleep time before the PO.

[0138] In an extension of the above embodiments, the UE further considers the current operating parameters when considering candidate sequences for RS utilization, including for example:

[0139] · The validity of the available AGC valuation from the previous wake-up, which depends on, for example, the time since the last AGC update, the change in the previously estimated RSSI metric in the network over time, etc. If the elapsed time or the change exceeds a predetermined threshold, the candidate sequence must accommodate the new AGC valuation.

[0140] · The validity of the current AFC and / or timing valuation, which depends on, for example, the time since the last AFC update. If the elapsed time exceeds a predetermined threshold, the candidate sequence must accommodate the new AFC valuation and / or timing reference valuation.

[0141] · The signal quality of the available RSs. At a higher SINR, reliable AFC and / or measurement operations require a smaller number of REs.

[0142] Aspect 2: The UE utilizes possible non-SSB RSs during the idle mode to save power

[0143] According to some embodiments, the UE detects the transmission mode of the second set of RSs through a learning mechanism. In this case, the UE senses that the TRS exists with a certain probability during the idle mode, but it is not guaranteed that the TRS exists. For example, the UE learns the mode of transmitting the TRS using a certain learning mechanism and then detects that the same mode is repeated in the idle / inactive mode. Like any detection and / or learning mechanism, this sensing is associated with a non-zero probability of error estimation. Alternatively, the UE may have detected the presence of the TRS during the current or previous TRS period in the idle / inactive state, but there is no information or guarantee that the TRS will continue to be available within a certain time interval in the future.

[0144] According to some embodiments, the UE determines which RS to use for idle mode tasks based on the available probability of the second set of RSs and the paging occasion pattern.

[0145] In one embodiment, according to the learned pattern, if the probability of the TRS existing is high, the UE may consider this to be ensured and adopt a mechanism similar to that described in aspect 1. The possible rare occurrence of error estimation is handled as a paging reception failure, and conventional recovery means are used in the NW. In addition, regarding robustness, the UE may perform TRS detection every time or every other time, etc., to ensure that the measured signal is actually the TRS. In this case, in one scheme, the UE may adopt a joint detection and estimation mechanism to jointly detect the TRS and then implement AGC / AFC. In another scheme, especially when each TRS spans more than one time slot, the UE may use the first time slot to detect the TRS, possibly using a lower-power radio, and then implement AGC / AFC if the TRS is detected. In the case where the TRS is not detected and no other RS is available for AGC / AFC operation, the UE may skip a PO. Thus, when determining the probability of the TRS existing, in one method, the UE can ensure that a probability is selected such that the specified maximum probability of missing a PO is not exceeded. For example, the UE may learn the paging strategy / pattern of the NW and observe that the NW pages the UE at least 3 times before giving up. Therefore, in this example, the UE may initially take a greater risk and tune its AGC / AFC based on the potential TRS before one or several POs. However, once the UE detects that it has missed the TRS, the UE can adjust its risk assessment and not perform AGC / AFC tuning on the potential TRS. But after a successful paging process, or alternatively after the current connection is released to the idle / inactive state, since the UE knows that it has not missed any paging since the last connection, the UE can start taking greater risks again and perform AGC / AFC based on the potentially existing TRS.

[0146] In another embodiment, if the probability of the existence of the TRS is low or below a specific threshold (e.g., the probability set in the previous embodiment), the UE may choose to use the TRS occasion only before the SSB to save power, so as to have the opportunity to use the SSB in the absence of the TRS. For example, if the order of the RS is as shown in Figure 3 : SSB_x, SSB_x+1, TRS, PO, the UE may rely only on the SSB for AGC / AFC operations and ignore the TRS, because if it relies on the TRS for, e.g., AFC, but the TRS does not exist, it may not be able to reliably decode the PO.

[0147] Alternatively, the UE may still use this TRS to save power, but if it is not detected, use a receiver with stronger power for PO monitoring to ensure that paging messages are not missed.

[0148] As shown in Figure 4 : In another example, if the occurrence order is SSB_x, TRS_x, SSB_x+1, TRS_x+1, PO, the UE may use SSB_x for AGC, then use TRS_x for AFC, and skip SSB_x+1 / TRS_x+1, and in the case where TRS_x is not detected, the UE may use SSB_x+1 as a fallback for AFC. In other words, if the TRS does not exist, the UE may take the risk of using those SSBs that are available as a backup before the PO. In another example, the occurrence order may be TRS, SSB_x, SSB_x+1, and PO. In this case, if the TRS occasion spans at least two time slots and the AGC / AFC validity remains until the PO, the UE may use the TRS of the two time slots for AGC / AFC and skip the two SSBs, and if the TRS is not detected, the UE may use the default operation on the two SSBs.

[0149] To execute the method in the UE 130, the UE 130 includes modules as shown in Figure 9 : The UE 130 includes a receiving module 910, a transmitting module 920, a determining module 930, a processing module 940, a memory 950, etc. The determining module 930 and the processing module 940 may be combined into one module, shown as a processor 960.

[0150] The method according to the embodiments herein may be implemented by one or more processors, such as the processor 960 in the UE130 together with computer program code for performing the functions and actions of the embodiments herein. The above program code may also be provided as a computer program product, for example, in the form of a data carrier 980 carrying the computer program code 970, as shown in Figure 9As shown, it is used to execute the embodiments herein when loaded into the UE 130. One such carrier can be in the form of a CD ROM disk. However, other data carriers (such as memory cards) are also feasible. In addition, the computer program code can be provided as pure program code on a server or in the cloud and downloaded to the UE 130.

[0151] The memory 950 in the UE 130 can include one or more memory units and can be arranged to store received information, measurement results, data, configurations, and applications to execute the methods herein when executed in the UE 130.

[0152] Some example embodiments numbered 1-17 will be described below.

[0153] Embodiment 1: A method for power saving in a wireless communication system, which is executed in a UE, wherein a first set of reference symbols (RS) and a second set of RS are transmitted in the wireless communication system, the method comprising:

[0154] Obtaining information about the transmission of the second set of RS;

[0155] Determining which RS to use for an idle mode task based on the obtained information about the transmission of the second set of RS.

[0156] Embodiment 2: The method according to Embodiment 1, wherein obtaining information about the transmission of the second set of RS includes receiving information from a network node.

[0157] Embodiment 3: The method according to Embodiment 2, wherein the information about the transmission of the second set of RS includes the resource elements in which the second set of RS exists during the idle mode.

[0158] Embodiment 4: The method according to Embodiment 2, wherein the information about the transmission of the second set of RS includes the availability of the second set of RS within a certain future time interval.

[0159] Embodiment 5: The method according to any one of Embodiments 2-4, wherein the information about the transmission of the second set of RS includes the time and frequency positions of the second set of RS, the resource element (RE) pattern in one or more symbols, the period, the code sequence, and the associated transmission configuration indication (TCI) state.

[0160] Embodiment 6: The method according to any one of Embodiments 2-5, wherein determining which RS to use for an idle mode task is based on the time order of the appearance of the first set of RS and the second set of RS and / or the paging occasion (PO) position.

[0161] Example 7: The method according to any one of Examples 2-5, wherein determining which RS to use for an idle mode task includes: determining an RS utilization sequence for the idle mode task by comparing the total energy consumption of the utilization sequences of a first set of RSs and a second set of RSs.

[0162] Example 8: The method according to Example 7, further comprising considering an operating parameter when determining the RS utilization sequence.

[0163] Example 9: The method according to Example 8, wherein the operating parameter includes any one of the following: the validity of an available idle mode measurement result AGC estimation from a previous wake-up, a current idle mode measurement result AFC, the validity of a timing estimation, and the signal quality of available RSs.

[0164] Example 10: The method according to Example 1, wherein obtaining information about the transmission of a second set of RSs includes: detecting a transmission mode of the second set of RSs through a learning mechanism.

[0165] Example 11: The method according to Example 1, wherein obtaining information about the transmission of a second set of RSs includes: estimating the availability of the second set of RSs within a future time interval based on the second set of RSs detected during current or previous transmission opportunities in the idle mode.

[0166] Example 12: The method according to Examples 10-11, wherein obtaining information about the transmission of a second set of RSs includes combining the detection of the transmission mode of the second set of RSs by the learning mechanism and the estimation of the availability of the second set of RSs based on the second set of RSs detected during current or previous transmission opportunities in the idle mode.

[0167] Example 13: The method according to Examples 10-12, wherein determining which RS to use for an idle mode task is based on the available probability of the second set of RSs and a paging occasion pattern.

[0168] Example 14: The method according to any one of Examples 1-13, wherein the first set of RSs includes a Synchronization Signal Block (SSB) and is transmitted periodically, and a second set of RSs is transmitted in addition to the SSB to support UE operation in the connected mode.

[0169] Example 15: The method according to any one of Examples 1-14, wherein the second set of RSs includes Tracking Reference Symbols (TRS).

[0170] Example 16: The method according to any one of Examples 1-14, wherein the second set of RSs includes Channel State Information Reference Signals (CSI-RS).

[0171] Example 17: The method according to any one of Examples 1-16 further includes determining a mode of a sleep pattern based on a chronological order in which a first set of RRs and a second set of RRs occur.

Claims

1. A method performed in a wireless communication device for power saving in a wireless communication system, wherein a first set of reference signals (RS) and a second set of RS are provided for transmission in the wireless communication system, the method comprising: Obtaining (210) information about the transmission of the second set of RS; Determining (220) which RS to use for idle mode tasks based on the obtained information about the transmission of the second set of RS, wherein determining (220) which RS to use for idle mode tasks includes: determining the RS utilization sequence for the idle mode tasks by comparing the total energy consumption of the utilization sequences of the first set of RS and the second set of RS; Wherein, the first set of RS is provided periodically, and the second set of RS is provided in any one of a periodic transmission mode, a semi-persistent transmission mode, or an aperiodic transmission mode; The method further includes: considering operating parameters when determining the RS utilization sequence; wherein the operating parameters include any one of the following items: the validity of the available idle mode measurement result automatic gain control (AGC) valuation from the previous wake-up, the current idle mode measurement result automatic frequency control (AFC), the validity of the timing valuation, and the signal quality of the available RS.

2. The method according to claim 1, wherein obtaining (210) information about the transmission of the second set of RS includes receiving information from a network node.

3. The method according to claim 2, wherein the information about the transmission of the second set of RS includes the resource elements in which the second set of RS exists during the idle mode.

4. The method according to claim 2, wherein the information about the transmission of the second set of RS includes the availability of the second set of RS within a certain future time interval.

5. The method according to claim 2, wherein the information about the transmission of the second set of RS includes one or more of the following items: the time and frequency of the second set of RS, the resource element (RE) pattern in one or more symbols, the period, the code sequence, the related transmission configuration indication (TCI) state.

6. The method according to claim 2, wherein determining (220) which RS to use for idle mode tasks is based on the occurrence of any one of the first set of RS and the second set of RS.

7. The method according to claim 2, wherein determining (220) which RS to use for idle mode tasks is based on the time order of the occurrence of the first set of RS and the second set of RS and the occurrence of the paging occasion (PO).

8. The method according to claim 1, wherein obtaining (210) information about the transmission of the second set of RSs comprises: Detecting the transmission mode of the second set of RS through a learning mechanism.

9. The method according to claim 1, wherein obtaining (210) information about the transmission of the second set of RSs comprises: Estimating the availability of the second set of RS within a certain future time interval based on the second set of RS detected during the current or previous transmission occasion in the idle mode.

10. The method according to claim 8, wherein obtaining (210) information about the transmission of the second set of RSs comprises: Combining the detection of the transmission mode of the second set of RS by the learning mechanism with the estimation of the availability of the second set of RS based on the second set of RS detected during the current or previous transmission occasion in the idle mode.

11. The method according to claim 8, wherein determining (220) which RS to use for an idle mode task is based on the available probability of the second set of RSs and the paging occasion pattern.

12. The method according to claim 1, wherein the first set of RSs includes synchronization signal blocks (SSBs), and the second set of RSs is transmitted in addition to the SSBs to support operation in the connected mode.

13. The method according to claim 1, wherein the second set of RSs includes tracking reference symbols (TRSs).

14. The method according to claim 1, wherein the second set of RSs includes channel state information reference signals (CSI-RSs).

15. The method according to any one of claims 1-14, further comprising determining a sleep mode pattern based on the chronological order of occurrence of the first set of RSs and the second set of RSs.

16. A wireless communication device (130) comprising a receiving module (910), a transmitting module (920), and a processor (960), the processor (960) including a determining module (930) and a processing module (940), wherein the wireless communication device is arranged to perform the method according to any one of claims 1-15.

Images