On-demand reference signal configuration

Abstract

The present disclosure is related to a terminal device, a network node, and methods for on- demand reference signal configuration. A method at a terminal device comprises: receiving, from a network node, a first message indicating a configuration for on-demand reference signals associated with one or more SCells; and performing one or more operations associated with the on-demand reference signals based on at least the configuration.

Description

[0001] ON-DEMAND REFERENCE SIGNAL CONFIGURATION

[0002] Technical Field

[0003] The present disclosure is related to the field of telecommunications, and in particular, to a terminal device, a network node, and methods for on-demand reference signal configuration. Background

[0004] With the development of the electronic and telecommunication technologies, mobile devices, such as mobile phones, smart phones, laptops, tablets, vehicle mounted devices, drones, become an important part of our daily lives. To support a numerous number of mobile devices, a highly energy efficient Radio Access Network (RAN), such as a fifth generation (5G) New Radio (NR) RAN, will be required.

[0005] Network energy saving (NES), being of great importance for environmental sustainability, to reduce environmental impact (greenhouse gas emissions) and for operational cost savings, has been studied from the 3rdGeneration Partnership Project (3GPP) Release 18.

[0006] Summary

[0007] Regarding those promising techniques which were raised but not specified, it is agreed that Work Item (WI), RP -234065, in Release 19 aims to study and specify them including on-demand Synchronous Signal (SS) and Physical Broadcast Channel (PBCH) block (SSB) and on-demand System Information Block 1 (SIB 1) transmissions, as well as adaptation of common signal / channel transmissions.

[0008] Among the techniques described above, on-demand SSB is considered to be an enhancement to secondary cell (SCell) activation operation, and the 3GPP Release 19 WI, RP- 234065, entitled ‘Enhancements of network energy savings for NR” includes the following objective related to on-demand SSB transmission:

[0009] However, it is unclear how the on-demand SSB (OD-SSB) can be configured for multiple SCells. For example, the SCells relevant for a first User Equipment (UE) may not always have the same SSB transmission status, e.g., a subset of SCells can already be providing SSBs for other UEs, while the other subset of SCells, to be activated for the first UE, are not currently transmitting OD-SSBs. Given that, it’s desirable to define mechanisms that are applicable to multiple OD-SSB configuration. To address or at least partially alleviate one or more of the above issues, some embodiments of the present disclosure are provided.

[0010] According to a first aspect of the present disclosure, a method at a terminal device is provided. The method comprises: receiving, from a network node, a first message indicating a configuration for on-demand reference signals associated with one or more SCells; and performing one or more operations associated with the on-demand reference signals based on at least the configuration. Further, some other embodiments of the first aspect will be provided in the Detailed Description below.

[0011] According to a second aspect of the present disclosure, a terminal device is provided. The terminal device comprises: a processor; a memory storing instructions which, when executed by the processor, cause the terminal device to: receive, from a network node, a first message indicating a configuration for on-demand reference signals associated with one or more SCells; and perform one or more operations associated with the on-demand reference signals based on at least the configuration. In some embodiments, the instructions, when executed by the processor, cause the terminal device to further perform any of the methods of the first aspect.

[0012] According to a third aspect of the present disclosure, a method at a network node is provided. The method comprises: transmitting, to a terminal device, a first message indicating a configuration for on-demand reference signals associated with one or more SCells to trigger the terminal device to perform one or more operations associated with the on-demand reference signals based on at least the configuration. Further, some other embodiments of the third aspect will be provided in the Detailed Description below.

[0013] According to a fourth aspect of the present disclosure, a network node is provided. The network node comprises: a processor; a memory storing instructions which, when executed by the processor, cause the network node to: transmit, to a terminal device, a first message indicating a configuration for on-demand reference signals associated with one or more SCells to trigger the terminal device to perform one or more operations associated with the on-demand reference signals based on at least the configuration. In some embodiments, the instructions, when executed by the processor, cause the network node to further perform any of the methods of the third aspect.

[0014] According to a fifth aspect of the present disclosure, a computer program comprising instructions is provided. The instructions, when executed by at least one processor, cause the at least one processor to carry out any of the methods of any of the first aspect and / or the third aspect.

[0015] According to a sixth aspect of the present disclosure, a carrier containing the computer program of the fifth aspect is provided. In some embodiments, the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium. According to a seventh aspect of the present disclosure, a telecommunication system is provided. The telecommunication system comprises: one or more terminal devices of the second aspect; and a network node of the fourth aspect.

[0016] With some embodiments of the present disclosure, when multiple OD-SSB SCells are to be activated without any active serving cell in the intra-band or inter-band co-located, based on network’s (NW) indication, UE is only needed to perform OD-SSB measurement and reporting in one of the OD-SSB SCells in the intra-band. The other OD-SSB SCells can still be kept in deep sleep till SCell activation. At the same time, the SCell activation delay for these OD-SSB SCells can also be shorter since OD-SSB measurement is already performed in one of the OD-SSB SCells in the intra-band.

[0017] Further, with some embodiments of the present disclosure, when multiple OD-SSB SCells are to be activated with one active serving cell in the intra-band or inter-band co-located, the OD- SSB SCells can be kept in deep sleep till SCell activation without deactivated SCell’s OD-SSB measurement. Based on NW’s indication, UE is only needed to perform faster OD-SSB SCells activation based on the active serving cell’s information.

[0018] Furthermore, with some embodiments of the present disclosure, when multiple OD-SSB measurements are configured for deactivated SCells, the OD-SSB indication with different offsets may guarantee that only one SCell’s OD-SSB transmission is performed during a configured period. Each OD-SSB SCell’s wake up time can be shorten based on a sequential measurement procedure to maximize the network power saving gain.

[0019] Furthermore, the proposed mechanism for on-demand reference signal configuration is also applicable when operations for single OD-SSB SCell is to be performed.

[0020] Brief Description of the Drawings

[0021] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and therefore are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

[0022] Fig. 1 is a diagram illustrating an exemplary telecommunication network in which UEs and a RAN node may be operated according to an embodiment of the present disclosure.

[0023] Fig. 2 is a diagram illustrating exemplary Carrier Aggregation (CA) modes with which UEs and a RAN node may be operated according to an embodiment of the present disclosure.

[0024] Fig. 3 is a diagram illustrating exemplary Medium Access Control (MAC) Control Elements (CEs) for SCell Activation / Deactivation. Fig. 4 is a diagram illustrating exemplary SSBs and an exemplary SSB Measurement Time Configuration (SMTC).

[0025] Fig. 5 is a diagram illustrating an exemplary OD-SSB configuration for OD-SSBs in multiple SCells with one of them configured for measurement according to an embodiment of the present disclosure.

[0026] Fig. 6 is a diagram illustrating an exemplary OD-SSB configuration for OD-SSBs in multiple SCells with more than one of them configured for measurement according to an embodiment of the present disclosure.

[0027] Fig. 7 is a diagram illustrating an exemplary OD-SSB configuration for OD-SSB bursts in multiple SCells according to an embodiment of the present disclosure.

[0028] Fig. 8 is a flow chart illustrating an exemplary method at a terminal device according to an embodiment of the present disclosure.

[0029] Fig. 9 is a flow chart illustrating an exemplary method at a network node according to an embodiment of the present disclosure.

[0030] Fig. 10 schematically shows an embodiment of an arrangement which may be used in a terminal device and / or a network node according to an embodiment of the present disclosure.

[0031] Fig. 11 shows an exemplary communication system in accordance with some embodiments.

[0032] Fig. 12 shows an exemplary UE in accordance with some embodiments.

[0033] Fig. 13 shows an exemplary network node in accordance with some embodiments.

[0034] Fig. 14 is a block diagram illustrating an exemplary virtualization environment in which functions implemented by some embodiments may be virtualized.

[0035] Detailed Description

[0036] Hereinafter, the present disclosure is described with reference to embodiments shown in the attached drawings. However, it is to be understood that those descriptions are just provided for illustrative purpose, rather than limiting the present disclosure. Further, in the following, descriptions of known structures and techniques are omitted so as not to unnecessarily obscure the concept of the present disclosure.

[0037] Of course, the present disclosure may be carried out in other specific ways than those set forth herein without departing from the scope and essential characteristics of the disclosure. One or more of the specific processes discussed below may be carried out in any electronic device comprising one or more appropriately configured processing circuits, which may in some embodiments be embodied in one or more application-specific integrated circuits (ASICs). In some embodiments, these processing circuits may comprise one or more microprocessors, microcontrollers, and / or digital signal processors programmed with appropriate software and / or firmware to carry out one or more of the operations described above, or variants thereof. In some embodiments, these processing circuits may comprise customized hardware to carry out one or more of the functions described above. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

[0038] Although multiple embodiments of the present disclosure will be illustrated in the accompanying Drawings and described in the following Detailed Description, it should be understood that the disclosure is not limited to the disclosed embodiments, but instead is also capable of numerous rearrangements, modifications, and substitutions without departing from the present disclosure that as will be set forth and defined within the claims.

[0039] Further, please note that although the following description of some embodiments of the present disclosure is given in the context of 5thGeneration New Radio (5G NR), the present disclosure is not limited thereto. In fact, as long as on-demand reference signal configuration is involved, the inventive concept of the present disclosure may be applicable to any appropriate communication architecture, for example, to Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Time Division - Synchronous CDMA (TD-SCDMA), CDMA2000, Worldwide Interoperability for Microwave Access (WiMAX), Wireless Fidelity (Wi-Fi), Long Term Evolution (LTE), etc. Therefore, one skilled in the arts could readily understand that the terms used herein may also refer to their equivalents in any other infrastructure. For example, the term “terminal device” used herein may refer to a UE, a mobile device, a mobile terminal, a mobile station, a user device, a user terminal, a wireless device, a wireless terminal, an Internet of Things (loT) device, a vehicle, or any other equivalents. For another example, the term “network node” used herein may refer to a base station, a base transceiver station, an access point, a hot spot, a NodeB (NB), an evolved NodeB (eNB), a gNB, a network element, a network node, a network function, an access network (AN) node, or any other equivalents.

[0040] The following 3 GPP documents are incorporated herein by reference in their entireties:

[0041] - 3GPP TS 38.133 V18.6.0 (2024-06), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Requirements for support of radio resource management (Release 18);

[0042] - 3GPP TS 38.321 V18.2.0 (2024-06), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Medium Access Control (MAC) protocol specification (Release 18); and

[0043] - 3GPP TSG RAN Meeting #102, RP -234065, “Enhancements of network energy savings for NR”. Fig. 1 is a diagram illustrating an exemplary telecommunication network 10 in which a UE #1 100-1, a UE #2 100-2, and a RAN node (e.g., a gNB) 105 may be operated according to an embodiment of the present disclosure. Although the telecommunication network 10 is a network defined in the context of 5G NR, the present disclosure is not limited thereto. As shown in Fig. 1, the network 10 may comprise one or more UEs 100-1 and 100-2 (collectively, UE(s) 100) and a RAN node 105, which could be a base station, a Node B, an evolved NodeB (eNB), a gNB, or an node which provides the UEs 100 with access to the network. Further, the network 10 may comprise its core network portion that is not shown in Fig. 1.

[0044] However, the present disclosure is not limited thereto. In some other embodiments, the network 10 may comprise additional nodes, less nodes, or some variants of the existing nodes shown in Fig. 1. For example, in a network with the 4G architecture, the entities (e.g., an eNB) which perform these functions may be different from those (e.g., the gNB 105) shown in Fig. 1. For another example, in a network with a mixed 4G / 5G architecture, some of the entities may be same as those shown in Fig. 1, and others may be different. Further, although two UEs 100 and one RAN node 105 are shown in Fig. 1, the present disclosure is not limited thereto. In some other embodiments, any number of UEs and / or any number of RAN nodes may be comprised in the network 10.

[0045] As shown in Fig. 1, the UEs 100 may be communicatively connected to the RAN node 105 which in turn may be communicatively connected to a corresponding Core Network (CN) and then the Internet, such that the UEs 100 may finally communicate its user plane data with other devices outside the network 10, for example, via the RAN node 105.

[0046] Carrier aggregation (CA) is used in Long Term Evolution Advanced (LTE-A) and NR in order to increase the bandwidth, and thereby increase the bitrate. Each aggregated carrier is referred to as a component carrier (CC). The easiest way to arrange aggregation would be to use contiguous component carriers within the same operating frequency band (as defined for LTE and NR), so called “intra-band contiguous” (see “Intra-band, contiguous” shown in Fig. 2). This might not always be possible, due to operator frequency allocation scenarios. For non-contiguous allocation, it could either be intra-band, i.e. the component carriers belong to the same operating frequency band, but have a gap, or gaps, in between (see “Intra-band, non-contiguous” shown in Fig. 2), or it could be inter-band, in which case the component carriers belong to different operating frequency bands (see “Inter-band, non-contiguous” shown in Fig. 2).

[0047] When carrier aggregation is used, there are a number of serving cells, one for each component carrier. For example, there are three component carriers and thus three serving cells 110-1, 110-2, and 110-3 (collectively, the serving cells 110) shown in Fig. 1. The coverage of the serving cells 110 may differ, for example due to that CCs on different frequency bands will experience different pathloss. The Radio Resource Control (RRC) connection is only handled by one cell, called “the primary cell”, served by the primary component carrier (PCC). For example, the cell #3 110-3 may be the primary cell for the UE #1 100-1 and the UE #2 100-2 when they are operated in the CA mode. The other component carriers are all referred to as secondary component carriers (SCC), serving the secondary cells (e.g., the cell #1 110-1 and the cell #2 110-2). The SCCs may be added and removed as required, while the PCC is typically changed at handover.

[0048] Different component carriers can be planned to provide different coverage, i.e. different cell size. In the case of inter-band carrier aggregation, the component carriers may experience different pathloss, which increases with increasing frequency. In the example shown in Fig. 1, carrier aggregation on all three component carriers can only be used for the UE #1 100-1, the UE #2 100-2 is not within the coverage area of the cell #1 110-1. Note that for UEs using the same set of CCs, they can have different PCC.

[0049] SCell activation / de-activation MAC CEs

[0050] Some exemplary MAC CEs for SCell Activation / Deactivation are shown in Fig. 3.

[0051] The SCell Activation / Deactivation MAC CE of one octet is identified by a MAC subheader with Logical Channel Identification (LCID) as specified in Table 6.2.1-1 of TS 38.321. It has a fixed size and consists of a single octet containing seven C-fields and one R-field (Reserve field). The SCell Activation / Deactivation MAC CE with one octet is defined as shown at (a) in Fig. 3.

[0052] - Ci: If there is an SCell configured for the MAC entity with SCelllndex i as specified in TS 38.331, this field indicates the activation / deactivation status of the SCell with SCelllndex i, else the MAC entity shall ignore the Ci field. The Ci field is set to 1 to indicate that the SCell with SCelllndex i shall be activated. The Ci field is set to 0 to indicate that the SCell with SCelllndex i shall be deactivated;

[0053] - R: Reserved bit, set to 0.

[0054] There is another MAC CE of four octets that can support up to 31 SCells, which is shown at (b) in Fig. 3. In this MAC CE signaling, network has to indicate clearly the wanted activation status for each configured SCell.

[0055] As specified in Clause 8.3 of TS 38.133, an SCell is known provided conditions are met for the SCell.

[0056] Known and unknown conditions

[0057] SCell known or unknown conditions are defined based on whether UE has reported the measurement reports to the NW.

[0058] As per TS 38.133:

[0059] The requirement for unknown SCell applies provided that the activation commands for Physical Downlink Control Channel (PDCCH) Transmission Configuration Indicator (TCI), Physical Downlink Shared Channel (PDSCH) TCI (when applicable), semi-persistent Channel State Information Reference Signal (CSI-RS) for Channel Quality Indication (CQI) reporting (when applicable), and configuration message for TCI of periodic CSI-RS for CQI reporting (when applicable) are based on the latest valid Layer 1 Reference Signal Received Power (Ll-RSRP) reporting.

[0060] Unknown SCell activation

[0061] When a UE receives SCell activation command for an SCell which does not meet the “known” condition, the SCell activation delay is longer. The UE will in this case perform the SCell activation based on the following steps (not necessarily in the given order):

[0062] - SCell activation MAC-CE decoding and Hybrid Automatic Repeat Request (HARQ) feedback;

[0063] - Automatic Gain Control (AGC) retuning (including Rx beam sweeping in FR2); - Coarse timing tracking (including Rx beam sweeping in FR2);

[0064] - Ll-RSRP measurement;

[0065] - Ll-RSRP reporting;

[0066] - Waiting NW TCI indication;

[0067] - Fine timing tracking; - Valid CSI reportings

[0068] SSB / SMTC

[0069] NR synchronization signal (SS) consists of primary SS (PSS) and secondary SS (SSS). NR physical broadcast channel (PBCH) carries the very basic system information. In a 5G NR RAN, PSS, PBCH, and SSS are always transmitted together and the combination of PSS, SSS, and PBCH is referred to as SSB in NR. Multiple SSBs may be transmitted in a localized burst set. Within an SSB burst set, multiple SSBs can be transmitted in different beams. The transmission of SSBs within a localized burst set may be confined to a 5 ms window (or a half-frame), and the SSB and SSB burst set may be repeated in a periodic manner. The SSB periodicity can be configured from the value set {5, 10, 20, 40, 80, 160} ms.

[0070] SSB is primarily used for performing the Radio Resource Management (RRM) measurements, beam measurements, synchronization measurements, etc., Since SSB periodicity can be as low as 5 ms, UEs do not need to perform RRM measurements or beam management measurements or synchronization measurements with the periodicity of SSB. To inform the UE about the SSB measurement periodicity, in NR, SSB measurement time configuration (SMTC) is introduced. SMTC consists of SMTC periodicity and SMTC window length / duration. In NR, since different beams can be configured to cover different spatial arrangements, UEs do not need to measure all the spatial directions. The beams to be measured can be controlled or configurable through SMTC window. SMTC window length / duration indicates the location of the SSB to be measured within the SSB burst set. The signaling of SMTC window informs the UE of the timing and periodicity of SSBs that the UE can use for measurements. The SMTC window periodicity can be configured from the value set {5, 10, 20, 40, 80, 160} ms, matching the possible SSB periodicities. The SMTC window duration can be configured from the value set {1, 2, 3, 4, 5} ms. The SMTC window duration may also be simply called as SMTC duration or SMTC length or SMTC occasion duration or SMTC occasion length etc. Fig. 4 provides an exemplary illustration of SSB and SMTC window. Referring to Fig. 4, multiple (e.g., four) SSB bursts are shown and some (e.g., two) of them can be used by a UE for measurement in SMTC windows as indicated by the dashed boxes. Further, as also shown in Fig. 4, each SSB burst may comprise four SSBs, each of which may be associated with a different beam.

[0071] Current Status in 3 GPP

[0072] In RANI #116 meeting, it was agreed that two scenarios will be supported for on-demand SSB.

[0073] As mentioned earlier, it is unclear how the OD-SSB can be configured for multiple SCells. Given that, it’s desirable to define mechanisms that are applicable to multiple OD-SSB configuration.

[0074] To address or at least partially alleviate one or more of the above issues, some embodiments of the present disclosure are provided.

[0075] Some embodiments of the present disclosure describe how to configure OD-SSBs for multiple SCells. To achieve power savings in a network, with the help of this Rel-19 network energy saving (NES) feature, i.e., on-demand SSB transmissions in general, some embodiments propose how to configure and activate multiple OD-SSBs’ transmissions in different SCells and / or how to inform the UE to perform SCell activations using the OD-SSBs. In some embodiments, a method at a UE is proposed, in which the UE may receive at least one message indicating the configuration and at least one message for the activation of multiple OD-SSBs transmission for multiple SCells. This is beneficial for the NW for power saving in multiple OD-SSB SCells to only trigger one OD-SSB transmission ahead of other OD-SSBs.

[0076] In some embodiments, some means are introduced, e.g., indicators in the configuration and / or activation of different OD-SSBs for multiple SCells. In some embodiments, the OD-SSB related parameters may be preconfigured by the higher layer (e.g., RRC) for different OD-SSBs for different OD-SSB based SCells, which are applicable later when invoked by the RRC, MAC- CE, or Downlink Control Information (DCI). In some embodiments, the different OD-SSB related parameters may be directly configured by the RRC, MAC-CE, or DCI. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, different timing offsets can be configured. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, different QCL relations can be configured. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, different deactivation OD-SSB timers can be configured. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, different time domain positions of the transmitted OD-SSBs in a half frame and / or an OD-SSB burst for multiple OD- SSB SCells can be configured. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, different reference cells can be configured for OD-SSB based SCells. In some embodiments, different OD-SSBs can be used for different purposes in different OD-SSB based SCells, such as deactivated SCell measurement and / or SCell activation etc.

[0077] In some embodiments, when there is no active serving cell in the intra-band (contiguous or non-contiguous) / same band / inter-band co-located with OD-SSB SCells, NW may configure one MAC-CE for multiple OD-SSBs’ indication with one or more of the following configurations. In some embodiments, NW can configure one OD-SSB SCell’s OD-SSB for measurement and other OD-SSBs for SCell activation. In such a case, after UE finishes the OD-SSB’s measurement and reporting in one SCell, all the OD-SSB SCells’ activation can be believed as known cells with shorter activation delays. In some embodiments, NW may configure multiple different SSB offsets to different OD-SSB SCells. In some embodiments, the offset between the OD-SSB for measurement in the SCell and the earliest OD-SSB for SCell activation may be larger than the time threshold Tmeas. In some embodiments, Tmeascan be pre-defined or indicated from NW, for example, based on the measurement period on this OD-SSB. In some embodiments, Tmeasmay be a minimum gap between measurement / reporting and activation to make sure UE has enough time to activate an SCell after measuring another SCell. In some embodiments, NW may configure TCI states of the OD-SSBs as follows: the OD-SSBs in different SCells may be QCL-TypeD with the OD-SSB of the SCell being measured; and / or the OD-SSBs in different SCells may be directly / indirectly QCL-TypeC with the OD-SSB of the SCell being measured. In some embodiments, NW may configure different transmission power of OD-SSB in different SCells. In some embodiments, NW may configure the same time domain positions (or odssb- PositionsInBurst) of the transmitted OD-SSBs in a half frame or an OD-SSB burst for different OD-SSB SCells.

[0078] In some embodiments, when there is an active serving cell in the intra-band (contiguous or non-contiguous) / same band / inter-band co-located with OD-SSB SCells, NW may configure one MAC-CE for multiple OD-SSBs’ indication with one or more of the following configurations. In some embodiments, NW may configure multiple different SSB offsets to different OD-SSB SCells. In some embodiments, the offsets of different OD-SSBs can be different, for example, due to SSB periodicity. In some embodiments, NW may configure the same odssb-PositionsInBurst of different OD-SSB SCells with the active serving cell on the same band and / or co-located band. In some embodiments, NW may configure TCI states of the OD-SSBs as follows: the OD-SSBs in different SCells may be QCL-TypeD with the OD-SSB of the active serving cell; and / or the OD- SSBs in different SCells may be directly / indirectly QCL-TypeC with the OD-SSB of the active serving cell. In some embodiments, NW may configure different transmission power of OD-SSBs in different SCells.

[0079] In some embodiments, when NW configures multiple SCell’s OD-SSB for measurement, to maximize the NES gain, NW can indicate OD-SSBs transmission with different offsets. In some embodiments, UE may be assumed to perform the multiple OD-SSB measurements sequentially. In some embodiments, when UE finishes the OD-SSB measurement for the 1stSCell, UE may continue with the OD-SSB measurement for the 2ndSCell, and so on. In some embodiments, the OD-SSB offsets for different SCells can be larger than the measurement period. In some embodiments, OD-SSBs’ deactivation timers can be different for different SCells’ OD-SSB. In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, optionally, periodicities and / or number of the OD-SSBs bursts can be configured differently together with the OD-SSBs’ offset, which means some SCells’ OD-SSBs may be transmitted in bursts periodically, and some SCells’ OD-SSBs may be transmitted with only one burst. In some embodiments, OD- SSBs in some of SCells may be transmitted in bursts periodically, i.e., train of bursts transmitted in periods. In some embodiments, OD-SSBs in some of SCells may be transmitted in bursts configured with the number of bursts.

[0080] In some embodiments, the OD-SSB configuration can be designed such that the UE may be required to perform measurements on the OD-SSBs of only one OD-SSB SCell. This SCell can be then used as a reference cell for the other intra-band OD-SSB SCells or collocated inter-band OD-SSB SCells (i.e., these SCells can stay in the sleep mode longer since the measurement on them can be skipped and at the same time they can be activated with shorter delay since the measurements from the reference cell can be reused).

[0081] With some embodiments of the present disclosure, when multiple OD-SSB SCells are to be activated without any active serving cell in the intra-band or inter-band co-located, based on network’s (NW) indication, UE is only needed to perform OD-SSB measurement and reporting in one of the OD-SSB SCells in the intra-band. The other OD-SSB SCells can still be kept in deep sleep till SCell activation. At the same time, the SCell activation delay for these OD-SSB SCells can also be shorter since OD-SSB measurement is already performed in one of the OD-SSB SCells in the intra-band.

[0082] Further, with some embodiments of the present disclosure, when multiple OD-SSB SCells are to be activated with one active serving cell in the intra-band or inter-band co-located, the OD- SSB SCells can be kept in deep sleep till SCell activation without deactivated SCell’s OD-SSB measurement. Based on NW’s indication, UE is only needed to perform faster OD-SSB SCells activation based on the active serving cell’s information.

[0083] Furthermore, with some embodiments of the present disclosure, when multiple OD-SSB measurements are configured for deactivated SCells, the OD-SSB indication with different offsets may guarantee that only one SCell’s OD-SSB transmission is performed during a configured period. Each OD-SSB SCell’s wake up time can be shorten based on a sequential measurement procedure to maximize the network power saving gain.

[0084] In some embodiments, examples of network nodes may comprise (but not limited to) at least one of: NodeB, base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB, gNodeB, MeNB, SeNB, location measurement unit (LMU), integrated access backhaul (IAB) node, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), Central Unit (e.g. in a gNB), Distributed Unit (e.g. in a gNB), Baseband Unit, Centralized Baseband, C-RAN, access point (AP), transmission points, transmission nodes, transmission reception point (TRP), RRU, RRH, nodes in distributed antenna system (DAS), core network node (e.g. MSC, MME etc.), O&M, OSS, SON, positioning node (e.g. E-SMLC), etc.

[0085] In some embodiments, the non-limiting term “UE” may refer to any type of wireless device communicating with a network node and / or with another UE in a cellular or mobile communication system. Examples of UE may comprise (but not limited to) at least one of: target device, device to device (D2D) UE, vehicular to vehicular (V2V), machine type UE, MTC UE or UE capable of machine to machine (M2M) communication, PDA, tablet, mobile terminals, smart phone, laptop embedded equipment (LEE), laptop mounted equipment (LME), USB dongles, etc.

[0086] In some embodiments, the term “radio access technology” or “RAT” may refer to any RAT e.g. UTRA, E-UTRA, narrow band internet of things (NB-IoT), WiFi, Bluetooth, next generation RAT, New Radio (NR), 4G, 5G, etc. Any of the equipment denoted by the term “node”, “network node” or “radio network node” may be capable of supporting a single or multiple RATs.

[0087] In some embodiments, the term “signal” or “radio signal” used herein may be any physical signal or physical channel. Examples of DL physical signals may comprise (but not limited to) at least one of: reference signal (RS) such as PSS, SSS, CSI-RS, DMRS signals in SS / PBCH block (SSB), discovery reference signal (DRS), CRS, PRS etc. In some embodiments, RS may be periodic e.g. RS occasion carrying one or more RSs may occur with certain periodicity e.g. 20 ms, 40 ms etc. In some embodiments, the RS may also be aperiodic. In some embodiments, each SSB may carry NR-PSS, NR-SSS, and NR-PBCH in 4 successive symbols. In some embodiments, one or multiple SSBs may be transmitted in one SSB burst which may be repeated with a certain periodicity e.g. 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, and 160 ms. In some embodiments, the UE may be configured with information about SSB on cells of certain carrier frequency by one or more SS / PBCH block measurement timing configuration (SMTC) configurations. In some embodiments, the SMTC configuration may comprise parameters including (but not limited to) at least one of: SMTC periodicity, SMTC occasion length in time or duration, SMTC time offset with respect to reference time (e.g. serving cell’s SFN) etc. Therefore, SMTC occasion may also occur with a certain periodicity e.g. 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, and 160 ms. Examples of UL physical signals may comprise (but not limited to) at least one of: reference signal such as SRS, DMRS etc. In some embodiments, the term “physical channel” may refer to any channel carrying higher layer information e.g. data, control, etc. Examples of physical channels may comprise (but not limited to) at least one of: PBCH, NPBCH, PDCCH, PDSCH, sPDCCH, sPDSCH, sPUCCH, sPUSCH, MPDCCH, NPDCCH, NPDSCH, E-PDCCH, PUSCH, PUCCH, NPUSCH, etc.

[0088] In some embodiments, the term “aperiodic-tracking reference signal” or “A-TRS” used herein is a Rel-17 application of the CSI-RS for the UE measurement to settle the AGC during the secondary cell activation timeline. A-TRS can be typical Non-Zero-Power (NZP) CSI-RS which follows the configuration from higher layer.

[0089] In some embodiments, the term “time resource” used herein may correspond to any type of physical resource or radio resource expressed in terms of length of time. Examples of time resources may comprise (but not limited to) at least one of: symbol, time slot, subframe, radio frame, TTI, interleaving time, slot, sub-slot, mini-slot, system frame number (SFN) cycle, hyper- SFN (H-SFN) cycle, etc.

[0090] In some embodiments, the MAC-CE that is used for indication of OD-SSBs status does not necessarily have to be the same as for SCell (de-)activation even though that MAC-CE was exemplified above. In other words, the MAC-CE may be any of: an extended version of the existing MAC-CE for SCell(s) (de-)activation including OD-SSB(s) information, or anew MAC- CE for SCell (de-)activation including OD-SSB information, or a separate MAC-CE including OD-SSB information which in turn may or may not be co-transmitted with another MAC-CE used for SCell (de-)activation.

[0091] Also, for the simplicity, MAC-CE may be used in some embodiments as a default signaling for activating / deactivating OD-SSB transmissions. However, the present disclosure is not limited thereto. In other words, the embodiments described with reference to MAC-CE may also be applicable to the scenarios in which different types of signaling (e.g., RRC or DCI) are used for activating / deactivating OD-SSB transmissions.

[0092] Scenarios

[0093] In some embodiments, in an OD-SSB based SCell scenario (e.g., Case #1 mentioned in the section “Current Status in 3GPP”), the NW has initially not configured the UE with any SSB transmission on the SCell. Therefore, from the UE’s perspective, there is no baseline SSB transmission (e.g., low-rate such as with 160 ms periodicity) ongoing in the background during this initial phase. Note that this is from the UE’s perspective, meaning that it could be so that during this period the NW is either not transmitting any SSB or the NW is actually transmitting SSBs but has not provided information about the SSB transmission to said UE. At a later point in time, the NW may indicate activation of a (high-rate) SSB periodicity (e.g., 5 ms) which in some embodiments is called as OD-SSB for performing measurement / SCell activation.

[0094] In some embodiments, in another OD-SSB based SCell scenario (e.g., Case #2 mentioned in the section “Current Status in 3GPP”), the NW has configured the UE with SSB configuration with a (low-rate) SSB periodicity (e.g., with 160 ms periodicity) as a baseline SSB in the background. At a later point in time, the NW may then additionally indicate activation of a (high- rate) SSB periodicity (e.g., 5 ms) which in some embodiments is called as OD-SSB to perform measurement / SCell activation.

[0095] In some embodiments, scenarios in which the NW configures multiple SCells are discussed, where one or more of the SCells may be operating with OD-SSBs. For example, one or more SCells may be operating as legacy with always-on SSB (e.g., at a 20 ms rate), one or more other SCells may be operating completely S SB-less (as legacy, for which the UE is configured to use other SCells as SSB reference), and one or more further SCells may be operating with OD- SSB. Furthermore, among the SCells with OD-SSB, there may be one or more SCells operating according to Case #1 while other SCells are operating according to Case #2. In some embodiments, it is described how the NW, through the same MAC-CE, configures and indicates different parameters for the different SCells operating with OD-SSBs.

[0096] OD-SSB configuration for multiple SCells

[0097] For the sake of terminology clarification: an Scell can be “configured” to the UE but not yet “activated”. In this case the configured SCell is “deactivated”. The NW can later activate and deactivate this SCell. Alternately, the NW may also have the option to upon configuration also activate the SCell in the same message.

[0098] In some embodiments, when the NW configures multiple SCells for which OD-SSBs are applicable, it is possible that, in one MAC-CE indication, the different OD-SSBs are indicated to be used by the UE for different purposes, such as deactivated SCell measurement and / or SCell activation, etc.

[0099] In some embodiments, as part of the higher layer signaling (e.g., RRC) in OD-SSB based SCell configuration, different OD-SSB related parameters may be preconfigured for the different OD-SSB based SCells which are applicable later when invoked by the lower layer signaling (e.g., MAC-CE).

[0100] In some embodiments, the different OD-SSB related parameters may be directly configured by the MAC-CE.

[0101] In some embodiments, the RRC configuration may also contain the information when the OD-SSB transmissions will be triggered (i.e., the case without later MAC-CE or DCI signaling). In some embodiments, each OD-SSB SCell can be configured with a parameter (a start / stop offset, a timer, or a time window), which indicates when and for how long the OD-SSBs will be transmitted on the cell, and / or indicates when and for how long a transmission of OD-SSB can be expected at the terminal device. In some embodiment, an OD-SSB SCell can provide on-demand reference signals (one or multiple with some periodicity or a burst) during, for example, a time window, but a particular UE may not need necessarily to keep “measuring” or “detecting” during the whole time window. In other words, it may be enough to “measure” / ”detect” on the subgroup of the reference signals transmitted during the time window. In some embodiments, the transmission time may be indicated in signaling, while for how long the UE use it to perform “measurement” may depend on UE implementation. In some embodiments, these parameters can have different or the same values for different SCells and they can be defined relative to the reception of the RRC message containing the OD-SSB configuration(s) or relative to another event. In some embodiments, the RRC message can contain a parameter that indicates whether the UE upon the reception of the RRC message should consider provided OD-SSB configuration for an SCell as activated or deactivated (i.e., whether the OD-SSB transmissions can be expected immediately upon the UE receives the RRC message or later when indicated via dynamic signaling).

[0102] In some embodiments, the parameters may either be configured per SCell, or per group of SCells (e.g., belonging to the same FR, or belonging to the same band / intra-band, or based on some other grouping criteria) or commonly configured for some or all SCells.

[0103] In some embodiments, a set of (e.g., a list ol) above parameters may be configured per SCell, group of SCells, or all SCells. Then in the MAC-CE OD-SSB activation command, the UE may be indicated which of the parameters are relevant for the different SCells, e.g., by indices per SCell pointing at one of parameters in the list of configured parameters.

[0104] In some embodiments, the RRC configuration can contain a set of different OD-SSB configurations that can be associated with SCells, and in the MAC-CE OD-SSB activation command, the UE may be indicated which of the OD-SSB configurations is applicable, i.e., via single index that points to a self-contained OD-SSB configuration instead to a single parameter.

[0105] In some embodiments, as part of the higher layer (e.g. RRC) SCell configuration, different parameters may be preconfigured for the different SCells for the different purposes later invoked by the MAC-CE (e.g., one set of parameters / values relevant for measurements, whereas another set of parameters / values relevant for SCell activation. Note that some of these may be common). Then in the MAC-CE OD-SSB activation command or based on receiving the MAC-CE for SCell activation, the UE may be indicated for which purpose and thereby the UE knows which of the parameters are relevant for the SCells.

[0106] In some embodiments, some SCells of NR may as per legacy be SSB-less, and the UE may be configured to use another cell’s (reference cell’s or default cell’s as defined in TS 38.133) SSB as the timing reference and AGC source. In some embodiments, a first SSB-less SCell may now use a second OD-SSB SCell as a reference, and as such first SCell indirectly becomes an OD-SSB while the OD-SSB itself is transmitted from the second SCell. In some embodiments, a first SSB- less SCell may now configure to transmit OD-SSB, and such first SCell becomes an OD-SSB SCell. The SSB-less SCell will be based on OD-SSB information to acquire the timing reference and AGC.

[0107] The parameters may include one or more of the following information:

[0108] Timing related information

[0109] - absolute time, e.g., a timetable / schedule of the SSBs. For example, in which frame numbers, and slot / symbols of those frames they are transmitted. The information can be for example relevant to the first instance, and the information about periodicity, duration, transmission cycle is separately configured.

[0110] - relative time: time offset relative to another activity, e.g., time offsets to different SCells SSB; and / or time offset to the activation command.

[0111] QCL related information

[0112] - The QCL source of the multiple OD-SSBs based on other active serving cell, e.g. one of the SSB in active serving cell can be the reference of other OD-SSBs in other SCells in the same band / intra-band contiguous cell / inter-band co-located cell.

[0113] - One of the OD-SSB as the QCL source of other OD-SSBs, e.g. one of the OD-SSB can be measured or the related SCell can be activated and it can be the reference of the other OD-SSB based SCells (e.g., the same band / intra-band contiguous cell / inter-band co-located cell).

[0114] SSB positions in OD-SSB burst

[0115] - The parameters related to the time domain positions of the transmitted OD-SSBs in a half frame for multiple OD-SSB SCell will be indicated, such as odssb-PositionsInBurst.

[0116] Reference cell information

[0117] - The reference cell can be configured to multiple OD-SSB SCells. The OD-SSB SCell can derive the timing information based on the reference cell if no OD-SSB transmission. UE will use the OD-SSB to derive the SCell’s timing information if the OD-SSB is transmitted. The default reference cell can be used to derive the OD-SSB SCell timing if no reference cell is indicated.

[0118] In some embodiments, there is no active serving cell in the intra-band contiguous / same band / inter-band co-located of OD-SSB SCells to be activated, and all the SCells to be activated are OD-SSB SCells. Single MAC-CE for multiple OD-SSBs’ activation indication may be configured with one or more of the following:

[0119] • In some embodiments, NW may configure multiple different SSB offsets to different OD-SSB SCells.

[0120] In some embodiments, the offset between the OD-SSB for measurement in the SCell and the earliest OD-SSB for SCell activation may be larger than the time threshold Tmeas. In some embodiments, Tmeascan be pre-defined or indicated from NW based on the measurement period on this OD-SSB.

[0121] • NW configures TCI states of the OD-SSBs

[0122] In some embodiments, the OD-SSBs in different SCells may be QCL-TypeD with the OD-SSB of the SCell being measured.

[0123] In some embodiments, the OD-SSBs in different SCells may be directly QCL-TypeC or indirectly by Tracking Reference Signal (TRS) with the OD-SSB of the SCell being measured.

[0124] • In some embodiments, NW may configure different transmission power of OD-SSB in different SCells. In some embodiments, the power difference may be less than a threshold Tpower. In some embodiments, Tpm,ercan be pre-defined or indicated from NW.

[0125] • In some embodiments, NW may configure the same odssb-PositionsInBurst for different OD-SSBs in SCells.

[0126] In some embodiments, to maximize the NW energy saving (NES) gain, NW can indicate only one OD-SSB SCell’s OD-SSB for measurement and all other OD-SSBs for SCell activation in the same band / intra-band. In some embodiments, after UE finishes the OD-SSB’s measurement and reporting of the cell quality in one SCell, all the OD-SSB SCells’ activation can be believed as known which means the SCell activation delay is shorter compared with unknown SCell activation delay.

[0127] For example, as shown in Fig. 5, three OD-SSB SCells in the same band are configured. NW may configure SCell 3’s OD-SSB with a short offset (Offset 3) and UE may be required to perform OD-SSB’s measurement in SCell 3. After UE finishes the measurement and reporting of the cell quality, the SCell 3 can be believed as known SCell with a shorter activation delay. At the same time, the SCell 1 and SCell 2 can use SCell 3 as the reference (such as to obtain the timing, and AGC information), and thus they can be also activated with a shorter activation delay.

[0128] In some embodiments, when there is at least one active serving cell in the intra-band contiguous / same band / inter-band co-located of OD-SSB SCells to be activated, all the OD-SSB SCells being activated can be believed as known cell with shorter activation delay based on the following configurations. In some embodiments, a single MAC-CE for multiple OD-SSBs’ activation indication may be configured with one or more of the following:

[0129] • In some embodiments, NW may indicate the OD-SSBs transmission for different SCells activation. • In some embodiments, NW may configure multiple different SSB offsets to different OD-SSB SCells. For example, the offset of different OD-SSBs can be different due to OD-SSB periodicity and offset.

[0130] • In some embodiments, NW may configure the same odssb-PositionsInBurst of different OD-SSB SCells with the active serving cell on the intra-band / same band.

[0131] • In some embodiments, NW may configure TCI states of the OD-SSBs.

[0132] In some embodiments, the OD-SSBs in different SCells may be QC-TypeD with the RS (s) of one active serving cell on that band.

[0133] In some embodiments, the OD-SSBs in different SCells may be directly QCL-TypeC or indirectly by TRS with the RS (s) of one active serving cell on that band.

[0134] • In some embodiments, NW may configure different transmission power of OD-SSB in different SCells. In some embodiments, the power difference may be less than a threshold Tpower. In some embodiments, Tpm,ercan be pre-defined or indicated from NW.

[0135] In some embodiments, NW may configure multiple SCell’s OD-SSB for measurement with different offsets. Optionally, OD-SSBs’ deactivation timer can be different for different SCells’ OD-SSB. In some embodiments, the measurement delay for SCells being measured may be scaled up with a scaling factor N, where N may be equal to the number of the parallel unknown to-be- activated OD-SSB SCell(s) only except the ones which fulfills one or more of the following conditions:

[0136] • contiguous (in the frequency domain) to an active serving cell in the same band, or to a known SCell in the same band; and

[0137] • a single SSB is used in the unknown OD-SSB SCell; or multiple SSBs are used in the unknown OD-SSB SCell and TCI state indication is provided by the same MAC PDU for OD-SSB activation.

[0138] ■ For example, if an OD-SSB SCell is unknown and belongs to FR1, then the OD- SSB SCell may become known (i.e., the OD-SSB beam to be used can be identified unambiguously) if one of the following conditions is met:

[0139] ♦ ‘ ssb-PositionlnBursf indicates only one SSB is being actually transmitted, or

[0140] ♦ ‘ ssb-PositionlnBursf indicates multiple SSBs and TCI indication is provided in same MAC PDU with SCell activation,

[0141] • ssb-PositionlnBurst is same as the one of contiguous known cell or contiguous active serving cell.

[0142] In some embodiments, to maximize the NES gain, NW may only wake up one OD-SSB SCell at a time. In some embodiments, UE may be assumed to perform OD-SSB measurement sequentially. When UE finishes the OD-SSB measurement for 1stSCell, UE may continue with the OD-SSB measurement for 2ndSCell, etc. In some embodiments, the total measurement delay may be N * measurement period for one OD-SSB SCell. In some embodiments, the OD-SSB can be deactivated based on different OD-SSB deactivation timers for different SCells. In this case, all OD-SSB SCells’ measurements will be sequentially performed to minimize the network energy consumption.

[0143] For example, as shown in Fig. 6, three OD-SSB SCells in the same band are configured. NW may configure different SCells with different measurement periods, for example, by setting different start / stop timing offsets. For example, NW may configure the shortest start timing offset, “Offset 1”, for SCell 1, the medium start timing offset, “Offset 2”, for SCell 2, and the longest start timing offset, “Offset 3”, for SCell 3, to start their measurements, respectively. In this way, three OD-SSB SCells’ measurements can be sequentially performed to minimize the network energy consumption.

[0144] SCell 3’s OD-SSB with a short offset (Offset 3) and UE may be required to perform OD- SSB’s measurement in SCell 3. After UE finishes the measurement and reporting of the cell quality, the SCell 3 can be believed as known SCell with a shorter activation delay. At the same time, the SCell 1 and SCell 2 can use SCell 3 as the reference (such as to obtain the timing, and AGC information), and thus they can be also activated with a shorter activation delay.

[0145] In some embodiments, the NW can configure dynamically the offsets for multiple SCell’s OD-SSB for measurement over time depending on at least one of: UE location, activation delay, traffic requirements, etc. For example, as shown in Fig. 5 and assuming that different SCells are located at different locations, the configuration shown in this figure can be applied if UE location is closer to SCell 3 compared to other SCells. In this way, the chances for UE to have a less delay with SCell 3 is higher when compared to other SCells because it has the shortest offset. Once the UE move to a different location e.g., closer to SCell 2, the offset for different SCells will be updated such that SCell 2 will have the shortest offset when compared to other SCells.

[0146] In some embodiments, the offsets values for different SCells can be related to SCell capabilities, e.g., the shortest offset may be for SCell with the highest throughput capacity, nonenergy saving cell, etc. For example, some UEs requiring less delay will be for SCell with shortest offset.

[0147] In some embodiments, the dynamic offset can also be applied if some UEs need to be transferred to other SCell, e.g., if the SCell wants to switch to energy saving mode by forcing some UEs to transfer to other SCell by increasing the offset. While those non-energy saving mode SCell will have shorter offset. In some embodiments, the dynamic offset can also be used for SSB interference avoidance by adjusting the offset dynamically. In some embodiments, it can also be used to avoid PRACH storm e.g., some offsets have PRACH storm, then other offset will be configured dynamically to be close to that offset with PRACH storm as long as interference between SSB can be avoided.

[0148] Periodicity of burst information

[0149] In some embodiments, when NW configures multiple OD-SSBs for multiple SCells, optionally, periodicities or the number of the OD-SSBs burst can be configured differently together with the OD-SSBs’ offset. It means some SCells’ OD-SSBs may be transmitted in a burst periodically, i.e., a train of burst transmitted in periods, where the first burst in a train is transmitted as indicated with the offset mentioned in the embodiments above or explicitly (e.g., with a separate parameter), and the train of bursts terminates when a configured timer expires, e.g., deactivation timer mentioned in the embodiments above, number of trains (of bursts) reached to a value, configured by the network, and some SCells’ OD-SSBs may be transmitted with only one burst, i.e. starts as indicated with the offset mentioned in the embodiments above or explicitly (e.g., with a separate parameter), and terminates when a configured timer expires, e.g., deactivation timer mentioned in the embodiments above. For example, as shown in Fig. 7, NW may indicate SCell 1 with multiple OD-SSBs bursts and SCell 2 with OD-SSB single burst.

[0150] Fig. 8 is a flow chart of an exemplary method 800 at a terminal device according to an embodiment of the present disclosure. The method 800 may be performed at a terminal device (e.g., the UEs 100 shown in Fig. 1) for on-demand reference signal configuration. The method 800 may comprise steps S810 and S820. However, the present disclosure is not limited thereto. In some other embodiments, the method 800 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 800 may be performed in a different order than that described herein. Further, in some embodiments, a step in the method 800 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in the method 800 may be combined into a single step.

[0151] The method 800 may begin at step S810 where the terminal device may receive, from a network node, a first message indicating a configuration for on-demand reference signals associated with one or more SCells.

[0152] At step S820, the terminal device may perform one or more operations associated with the on-demand reference signals based on at least the configuration.

[0153] In some embodiments, the one or more operations may comprise at least one of: synchronizing with at least one of the SCells in the time domain and / or in the frequency domain; measuring at least one of the on-demand reference signals; and activating at least one of the SCells. In some embodiments, the on-demand reference signals comprise on-demand Synchronous Signal (SS) and Physical Broadcast Channel (PBCH) blocks (SSBs).

[0154] In some embodiments, the configuration may be indicated by at least one of: a Radio Resource Control (RRC) message; a Medium Access Control (MAC) Control Element (CE); and a Downlink Control Information (DCI). In some embodiments, when the configuration is indicated by a MAC CE, the MAC CE may be at least one of: an existing MAC CE for SCell activation or deactivation, which is extended to indicate the configuration; a MAC CE for SCell activation or deactivation, which is defined separately from an existing MAC CE for SCell activation or deactivation; and a MAC CE for indicating the configuration, which is able to be transmitted separately from a MAC CE for SCell activation or deactivation. In some embodiments, the configuration may indicate, for at least one of the SCells, at least one of: a first timing offset indicating when transmission of a corresponding on-demand reference signal is to be started; a second timing offset indicating when transmission of a corresponding on-demand reference signal is to be stopped; a duration, a timer, or a time window indicating for how long a transmission of corresponding on-demand reference signals can be expected; an indicator indicating whether the terminal device, upon the reception of the first message, is to consider the configuration as activated or deactivated for the corresponding SCell; a periodicity of a corresponding on-demand reference signal to be transmitted; a periodicity of a corresponding on-demand reference signal burst to be transmitted; a number of corresponding on-demand reference signal burst to be transmitted; a Quasi-Co-Location (QCL) relation; a timer for SCell deactivation; a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst to be transmitted; a reference cell; a purpose of a corresponding on-demand reference signal; and a transmission power.

[0155] In some embodiments, at least one parameter indicated by the configuration may be at least one of: a parameter specific to an SCell; a parameter specific to an SCell group; and a parameter common to all the SCells. In some embodiments, the first message may indicate one or more parameters in the configuration by at least one of: directly comprising one or more parameters; and indicating one or more parameters that are previously configured at the terminal device. In some embodiments, the one or more parameters that are previously configured at the terminal device may comprise at least one of: a set of parameters, wherein one or more parameters in the set to be used by the terminal device are indicated by the first message; a set of configurations, wherein one of the configurations to be used by the terminal device is indicated by the first message; and multiple sets of parameters, wherein each set is associated with a purpose of on- demand reference signals, and wherein for at least one of the SCells indicated by the configuration, one of the multiple sets to be used by the terminal device is indicated by the purpose of a corresponding on-demand reference signal associated with the corresponding SCell.

[0156] In some embodiments, the configuration may indicate that a first on-demand reference signal associated with a first of the SCells is used for measurement and that one or more second on-demand reference signals associated with one or more second SCells, which are intra-band contiguous, intra-band non-contiguous, or inter-band collocated with the first SCell, are used for SCell activation. In some embodiments, upon the reception of the first message, the terminal device may have no active serving cell that is intra-band contiguous, intra-band non-contiguous, or inter-band collocated with any of the SCells indicated by the configuration. In some embodiments, the configuration may indicate one or more parameters such that a time length between the first on-demand reference signal and the earliest on-demand reference signal for SCell activation may be longer than a pre-defined or configured time threshold. In some embodiments, the configuration may indicate that the one or more second on-demand reference signals are Quasi- Co-Located (QCLed) with the first on-demand reference signal with a QCL type selected from a group comprising at least one of: QCL-typeA, QCL-typeB, QCL-typeC, and QCL-typeD. In some embodiments, the configuration may indicate that the one or more second on-demand reference signals have a same time domain position in corresponding on-demand reference signal bursts as that of the first on-demand reference signal.

[0157] In some embodiments, upon the reception of the first message, the terminal device may have an active serving cell that is intra-band contiguous, intra-band non-contiguous, or inter-band collocated with one or more third SCells indicated by the configuration. In some embodiments, the configuration may indicate that one or more third on-demand reference signals associated with the one or more third SCells are used for SCell activation. In some embodiments, the configuration may indicate that the one or more third on-demand reference signals have a same time domain position in corresponding on-demand reference signal bursts as that of a reference signal associated with the active serving cell in a corresponding reference signal burst. In some embodiments, the configuration may indicate that the one or more third on-demand reference signals are QCLed with a reference signal associated with the active serving cell with a QCL type selected from a group comprising at least one of QCL-typeA, QCL-typeB, QCL-typeC, and QCL-typeD. In some embodiments, when the configuration indicates that multiple on-demand reference signals associated with multiple of the SCells are used for measurements, the configuration may indicate one or more parameters such that multiple measurement periods, during which measurements of the multiple on-demand reference signals are performed, respectively, occur sequentially. In some embodiments, the configuration may indicate one or more parameters such that a time length between an on-demand reference signal associated with an SCell for measurement and another on- demand reference signal associated with another SCell for measurement is longer than a time length of a measurement period. In some embodiments, an on-demand reference signal associated with an SCell for measurement may have a measurement delay unless the SCell is at least one of: an SCell that is contiguous to an active serving cell in the same band or to a known SCell in the same band; an SCell for which a single on-demand reference signal is configured; an SCell for which multiple on-demand reference signals are configured and a Transmission Configuration Indicator (TCI) is indicated by the configuration; and an SCell for which a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst is same as that of a contiguous active serving cell in the same band or a contiguous known SCell in the same band.

[0158] In some embodiments, one or more timing offsets may be defined relative to at least one of: the reception of the first message; and a reference signal associated with a SCell different from the SCell for which the one or more timing offsets are defined. In some embodiments, when the configuration indicates that two or more on-demand reference signals associated with two or more SCells are QCLed with each other with a QCL TypeC, the two or more on-demand reference signals may be QCLed directly or via a Tracking Reference Signal (TRS), and / or when the configuration indicates that one or more on-demand reference signals associated with one or more SCells are QCLed with a reference signal associated with an active serving cell with a QCL TypeC, the one or more on-demand reference signals may be QCLed with the reference signal directly or via a TRS.

[0159] In some embodiments, when the configuration indicates two or more transmission power associated with two or more on-demand reference signals, a difference between any two of the on- demand reference signals may be less than a threshold power. In some embodiments, the configuration may indicate a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the terminal device is located closer to the SCell than the other SCell. In some embodiments, the configuration may indicate a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the SCell has a higher capability than the other SCell.

[0160] Fig. 9 is a flow chart of an exemplary method 900 at a network node according to an embodiment of the present disclosure. The method 900 may be performed at a network node (e.g., the RAN node 105 shown in Fig. 1) for on-demand reference signal configuration. The method 900 may comprise a step S910. However, the present disclosure is not limited thereto. In some other embodiments, the method 900 may comprise more steps, different steps, or any combination thereof. Further the steps of the method 900 may be performed in a different order than that described herein. Further, in some embodiments, a step in the method 900 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in the method 900 may be combined into a single step.

[0161] The method 900 may begin at step S910 where the network node may transmit, to a terminal device, a first message indicating a configuration for on-demand reference signals associated with one or more SCells to trigger the terminal device to perform one or more operations associated with the on-demand reference signals based on at least the configuration.

[0162] In some embodiments, the one or more operations may comprise at least one of: synchronizing with at least one of the SCells in the time domain and / or in the frequency domain; measuring at least one of the on-demand reference signals; and activating at least one of the SCells. In some embodiments, the on-demand reference signals may comprise on-demand SSBs.

[0163] In some embodiments, the configuration may be indicated by at least one of: an RRC message; a MAC CE; and a DCI. In some embodiments, when the configuration is indicated by a MAC CE, the MAC CE may be at least one of: an existing MAC CE for SCell activation or deactivation, which is extended to indicate the configuration; a MAC CE for SCell activation or deactivation, which is defined separately from an existing MAC CE for SCell activation or deactivation; and a MAC CE for indicating the configuration, which is able to be transmitted separately from a MAC CE for SCell activation or deactivation. In some embodiments, the configuration may indicate, for at least one of the SCells, at least one of: a first timing offset indicating when transmission of a corresponding on-demand reference signal is to be started; a second timing offset indicating when transmission of a corresponding on-demand reference signal is to be stopped; a duration, a timer, or a time window indicating for how long a transmission of corresponding on-demand reference signals can be expected; an indicator indicating whether the terminal device, upon the reception of the first message, is to consider the configuration as activated or deactivated for the corresponding SCell; a periodicity of a corresponding on-demand reference signal to be transmitted; a periodicity of a corresponding on-demand reference signal burst to be transmitted; a number of corresponding on-demand reference signal burst to be transmitted; a Quasi-Co-Location (QCL) relation; a timer for SCell deactivation; a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst to be transmitted; a reference cell; a purpose of a corresponding on-demand reference signal; and a transmission power.

[0164] In some embodiments, at least one parameter indicated by the configuration may be at least one of: a parameter specific to an SCell; a parameter specific to an SCell group; and a parameter common to all the SCells. In some embodiments, the first message indicates one or more parameters in the configuration by at least one of: directly comprising one or more parameters; and indicating one or more parameters that are previously configured at the terminal device. In some embodiments, the one or more parameters that are previously configured at the terminal device may comprise at least one of: a set of parameters, wherein one or more parameters in the set to be used by the terminal device are indicated by the first message; a set of configurations, wherein one of the configurations to be used by the terminal device is indicated by the first message; and multiple sets of parameters, wherein each set is associated with a purpose of on-demand reference signals, and wherein for at least one of the SCells indicated by the configuration, one of the multiple sets to be used by the terminal device is indicated by the purpose of a corresponding on-demand reference signal associated with the corresponding SCell.

[0165] In some embodiments, the configuration may indicate that a first on-demand reference signal associated with a first of the SCells is used for measurement and that one or more second on-demand reference signals associated with one or more second SCells, which are intra-band contiguous, intra-band non-contiguous, or inter-band collocated with the first SCell, are used for SCell activation. In some embodiments, upon the reception of the first message, the terminal device may have no active serving cell that is intra-band contiguous, intra-band non-contiguous, or inter-band collocated with any of the SCells indicated by the configuration. In some embodiments, the configuration may indicate one or more parameters such that a time length between the first on-demand reference signal and the earliest on-demand reference signal for SCell activation is longer than a pre-defined or configured time threshold. In some embodiments, the configuration may indicate that the one or more second on-demand reference signals are QCLed with the first on-demand reference signal with a QCL type selected from a group comprising at least one of: QCL-typeA, QCL-typeB, QCL-typeC, and QCL-typeD.

[0166] In some embodiments, the configuration may indicate that the one or more second on- demand reference signals have a same time domain position in corresponding on-demand reference signal bursts as that of the first on-demand reference signal. In some embodiments, upon the reception of the first message, the terminal device may have an active serving cell that is intra- band contiguous, intra-band non-contiguous, or inter-band collocated with one or more third SCells indicated by the configuration. In some embodiments, the configuration may indicate that one or more third on-demand reference signals associated with the one or more third SCells are used for SCell activation. In some embodiments, the configuration may indicate that the one or more third on-demand reference signals have a same time domain position in corresponding on- demand reference signal bursts as that of a reference signal associated with the active serving cell in a corresponding reference signal burst. In some embodiments, the configuration may indicate that the one or more third on-demand reference signals are QCLed with a reference signal associated with the active serving cell with a QCL type selected from a group comprising at least one of QCL-typeA, QCL-typeB, QCL-typeC, and QCL-typeD. In some embodiments, when the configuration indicates that multiple on-demand reference signals associated with multiple of the SCells are used for measurements, the configuration may indicate one or more parameters such that multiple measurement periods, during which measurements of the multiple on-demand reference signals are performed, respectively, occur sequentially. In some embodiments, the configuration may indicate one or more parameters such that a time length between an on-demand reference signal associated with an SCell for measurement and another on-demand reference signal associated with another SCell for measurement is longer than a time length of a measurement period. In some embodiments, an on- demand reference signal associated with an SCell for measurement may have a measurement delay unless the SCell is at least one of: an SCell that is contiguous to an active serving cell in the same band or to a known SCell in the same band; an SCell for which a single on-demand reference signal is configured; an SCell for which multiple on-demand reference signals are configured and a TCI is indicated by the configuration; and an SCell for which a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst is same as that of a contiguous active serving cell in the same band or a contiguous known SCell in the same band.

[0167] In some embodiments, one or more timing offsets may be defined relative to at least one of: the reception of the first message; and a reference signal associated with a SCell different from the SCell for which the one or more timing offsets are defined. In some embodiments, when the configuration indicates that two or more on-demand reference signals associated with two or more SCells are QCLed with each other with a QCL TypeC, the two or more on-demand reference signals may be QCLed directly or via a TRS, and / or when the configuration indicates that one or more on-demand reference signals associated with one or more SCells are QCLed with a reference signal associated with an active serving cell with a QCL TypeC, the one or more on-demand reference signals may be QCLed with the reference signal directly or via a TRS. In some embodiments, when the configuration indicates two or more transmission power associated with two or more on-demand reference signals, a difference between any two of the on-demand reference signals may be less than a threshold power. In some embodiments, the configuration may indicate a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the terminal device is located closer to the SCell than the other SCell. In some embodiments, the configuration may indicate a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the SCell has a higher capability than the other SCell.

[0168] Fig. 10 schematically shows an embodiment of an arrangement which may be used in a terminal device and / or a network node according to an embodiment of the present disclosure. Comprised in the arrangement 1000 are a processing unit 1006, e.g., with a Digital Signal Processor (DSP) or a Central Processing Unit (CPU). The processing unit 1006 may be a single unit or a plurality of units to perform different actions of procedures described herein. The arrangement 1000 may also comprise an input unit 1002 for receiving signals from other entities, and an output unit 1004 for providing signal(s) to other entities. The input unit 1002 and the output unit 1004 may be arranged as an integrated entity or as separate entities.

[0169] Furthermore, the arrangement 1000 may comprise at least one computer program product 1008 in the form of a non-volatile or volatile memory, e.g., an Electrically Erasable Programmable Read-Only Memory (EEPROM), a flash memory and / or a hard drive. The computer program product 1008 comprises a computer program 1010, which comprises code / computer readable instructions, which when executed by the processing unit 1006 in the arrangement 1000 causes the arrangement 1000 and / or the terminal device and / or the network node in which it is comprised to perform the actions, e.g., of the procedure described earlier or any other variant.

[0170] The computer program 1010 may be configured as a computer program code structured in computer program modules 1010A and 1010B. Hence, in an exemplifying embodiment when the arrangement 1000 is used in a terminal device for on-demand reference signal configuration, the code in the computer program of the arrangement 1000 includes: a module 1010A configured to receive, from a network node, a first message indicating a configuration for on-demand reference signals associated with one or more SCells; and a module 1010B configured to perform one or more operations associated with the on-demand reference signals based on at least the configuration.

[0171] Additionally or alternatively, the computer program 1010 may be configured as a computer program code structured in a computer program module 1010C. Hence, in an exemplifying embodiment when the arrangement 1000 is used in a network node for on-demand reference signal configuration, the code in the computer program of the arrangement 1000 includes: a module 1010C configured to transmit, to a terminal device, a first message indicating a configuration for on-demand reference signals associated with one or more SCells to trigger the terminal device to perform one or more operations associated with the on-demand reference signals based on at least the configuration.

[0172] The computer program modules could essentially perform the actions of the flow illustrated in Fig. 5 through Fig. 9, to emulate the terminal device and / or the network node. In other words, when the different computer program modules are executed in the processing unit 1006, they may correspond to different modules in the terminal device and / or the network node.

[0173] Although the code means in the embodiments disclosed above in conjunction with Fig. 10 are implemented as computer program modules which when executed in the processing unit causes the arrangement to perform the actions described above in conjunction with the figures mentioned above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

[0174] The processor may be a single CPU (Central processing unit), but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and / or related chips sets and / or special purpose microprocessors such as Application Specific Integrated Circuit (ASICs). The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-access memory (RAM), a Read- Only Memory (ROM), or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the terminal device and / or the network node.

[0175] Fig. 11 shows an example of a communication system QQ100 in accordance with some embodiments.

[0176] In the example, the communication system QQ100 includes a telecommunication network QQ102 that includes an access network QQ104, such as a radio access network (RAN), and a core network QQ106, which includes one or more core network nodes QQ108. The access network QQ104 includes one or more access network nodes, such as network nodes QQ110A and QQ110B (one or more of which may be generally referred to as network nodes QQ110), or any other similar 3rdGeneration Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network QQ102 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network QQ102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network QQ102, including one or more network nodes QQ110 and / or core network nodes QQ108.

[0177] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or anon-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the 0-RAN Alliance or comparable technologies. The network nodes QQ110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs QQ112A, QQ112B, QQ112C, and QQ112D (one or more of which may be generally referred to as UEs QQ112) to the core network QQ106 over one or more wireless connections.

[0178] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system QQ100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system QQ100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0179] The UEs QQ112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes QQ110 and other communication devices. Similarly, the network nodes QQ110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs QQ112 and / or with other network nodes or equipment in the telecommunication network QQ102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network QQ102.

[0180] In the depicted example, the core network QQ106 connects the network nodes QQ110 to one or more host computing systems, such as host QQ116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network QQ106 includes one more core network nodes (e.g., core network node QQ108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node QQ108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0181] The host QQ116 may be under the ownership or control of a service provider other than an operator or provider of the access network QQ104 and / or the telecommunication network QQ102. The host QQ116 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0182] As a whole, the communication system QQ100 of Fig. 11 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0183] In some examples, the telecommunication network QQ102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network QQ102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network QQ102. For example, the telecommunications network QQ102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT services to yet further UEs. In some examples, the UEs QQ112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network QQ104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network QQ104. Additionally, a UE may be configured for operating in single- or multi -RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0184] In the example, the hub QQ114 communicates with the access network QQ104 to facilitate indirect communication between one or more UEs (e.g., UE QQ112C and / or QQ112D) and network nodes (e.g., network node QQ110B). In some examples, the hub QQ114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub QQ114 may be a broadband router enabling access to the core network QQ106 for the UEs. As another example, the hub QQ114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes QQ110, or by executable code, script, process, or other instructions in the hub QQ114. As another example, the hub QQ114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub QQ114 may be a content source. For example, for a UE that is a Virtual Reality (VR) device, display, loudspeaker, or other media delivery device, the hub QQ114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub QQ114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub QQ114 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0185] The hub QQ114 may have a constant / persistent or intermittent connection to the network node QQ110B. The hub QQ114 may also allow for a different communication scheme and / or schedule between the hub QQ114 and UEs (e.g., UE QQ112C and / or QQ112D), and between the hub QQ114 and the core network QQ106. In other examples, the hub QQ114 is connected to the core network QQ106 and / or one or more UEs via a wired connection. Moreover, the hub QQ114 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network QQ104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes QQ110 while still connected via the hub QQ114 via a wired or wireless connection. In some embodiments, the hub QQ114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node QQ110B. In other embodiments, the hub QQ114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node QQ110B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0186] Fig. 12 shows a UE QQ200 in accordance with some embodiments. The UE QQ200 presents additional details of some embodiments of the UE QQ112 of Fig. 11. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage / playback device, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), an Augmented Reality (AR) or Virtual Reality (VR) device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rdGeneration Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0187] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0188] The UE QQ200 includes processing circuitry QQ202 that is operatively coupled via a bus QQ204 to an input / output interface QQ206, a power source QQ208, a memory QQ210, a communication interface QQ212, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Fig. 12. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0189] The processing circuitry QQ202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory QQ210. The processing circuitry QQ202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry QQ202 may include multiple central processing units (CPUs).

[0190] In the example, the input / output interface QQ206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE QQ200. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0191] In some embodiments, the power source QQ208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source QQ208 may further include power circuitry for delivering power from the power source QQ208 itself, and / or an external power source, to the various parts of the UE QQ200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source QQ208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source QQ208 to make the power suitable for the respective components of the UE QQ200 to which power is supplied.

[0192] The memory QQ210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory QQ210 includes one or more application programs QQ214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data QQ216. The memory QQ210 may store, for use by the UE QQ200, any of a variety of various operating systems or combinations of operating systems.

[0193] The memory QQ210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory QQ210 may allow the UE QQ200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory QQ210, which may be or comprise a device-readable storage medium.

[0194] The processing circuitry QQ202 may be configured to communicate with an access network or other network using the communication interface QQ212. The communication interface QQ212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna QQ222. The communication interface QQ212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter QQ218 and / or a receiver QQ220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter QQ218 and receiver QQ220 may be coupled to one or more antennas (e.g., antenna QQ222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0195] In the illustrated embodiment, communication functions of the communication interface QQ212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0196] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface QQ212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0197] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0198] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE QQ200 shown in Fig. 12.

[0199] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0200] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0201] Fig. 13 shows a network node QQ300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0202] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0203] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs). The network node QQ300 includes a processing circuitry QQ302, a memory QQ304, a communication interface QQ306, and a power source QQ308. The network node QQ300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node QQ300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node QQ300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory QQ304 for different RATs) and some components may be reused (e.g., a same antenna QQ310 may be shared by different RATs). The network node QQ300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node QQ300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node QQ300.

[0204] The processing circuitry QQ302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node QQ300 components, such as the memory QQ304, to provide network node QQ300 functionality.

[0205] In some embodiments, the processing circuitry QQ302 includes a system on a chip (SOC). In some embodiments, the processing circuitry QQ302 includes one or more of radio frequency (RF) transceiver circuitry QQ312 and baseband processing circuitry QQ314. In some embodiments, the radio frequency (RF) transceiver circuitry QQ312 and the baseband processing circuitry QQ314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry QQ312 and baseband processing circuitry QQ314 may be on the same chip or set of chips, boards, or units.

[0206] The memory QQ304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry QQ302. The memory QQ304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry QQ302 and utilized by the network node QQ300. The memory QQ304 may be used to store any calculations made by the processing circuitry QQ302 and / or any data received via the communication interface QQ306. In some embodiments, the processing circuitry QQ302 and memory QQ304 is integrated.

[0207] The communication interface QQ306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface QQ306 comprises port(s) / terminal(s) QQ316 to send and receive data, for example to and from a network over a wired connection. The communication interface QQ306 also includes radio front-end circuitry QQ318 that may be coupled to, or in certain embodiments a part of, the antenna QQ310. Radio front-end circuitry QQ318 comprises filters QQ320 and amplifiers QQ322. The radio front-end circuitry QQ318 may be connected to an antenna QQ310 and processing circuitry QQ302. The radio front-end circuitry may be configured to condition signals communicated between antenna QQ310 and processing circuitry QQ302. The radio frontend circuitry QQ318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry QQ318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters QQ320 and / or amplifiers QQ322. The radio signal may then be transmitted via the antenna QQ310. Similarly, when receiving data, the antenna QQ310 may collect radio signals which are then converted into digital data by the radio front-end circuitry QQ318. The digital data may be passed to the processing circuitry QQ302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0208] In certain alternative embodiments, the network node QQ300 does not include separate radio front-end circuitry QQ318, instead, the processing circuitry QQ302 includes radio front-end circuitry and is connected to the antenna QQ310. Similarly, in some embodiments, all or some of the RF transceiver circuitry QQ312 is part of the communication interface QQ306. In still other embodiments, the communication interface QQ306 includes one or more ports or terminals QQ316, the radio front-end circuitry QQ318, and the RF transceiver circuitry QQ312, as part of a radio unit (not shown), and the communication interface QQ306 communicates with the baseband processing circuitry QQ314, which is part of a digital unit (not shown).

[0209] The antenna QQ310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna QQ310 may be coupled to the radio front-end circuitry QQ318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna QQ310 is separate from the network node QQ300 and connectable to the network node QQ300 through an interface or port.

[0210] The antenna QQ310, communication interface QQ306, and / or the processing circuitry QQ302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna QQ310, the communication interface QQ306, and / or the processing circuitry QQ302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0211] The power source QQ308 provides power to the various components of network node QQ300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source QQ308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node QQ300 with power for performing the functionality described herein. For example, the network node QQ300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source QQ308. As a further example, the power source QQ308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0212] Embodiments of the network node QQ300 may include additional components beyond those shown in Fig. 13 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node QQ300 may include user interface equipment to allow input of information into the network node QQ300 and to allow output of information from the network node QQ300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node QQ300. In some embodiments providing a core network node, such as core network node 108 of Fig. 11, some components, such as the radio front-end circuitry QQ318 and the RF transceiver circuitry QQ312 may be omitted.

[0213] Fig. 14 is a block diagram illustrating a virtualization environment QQ400 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments QQ400 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment QQ400 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface. Virtualization may facilitate distributed implementations of a network node, UE, core network node, or host.

[0214] Applications QQ402 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0215] Hardware QQ404 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers QQ406 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs QQ408a and QQ408b (one or more of which may be generally referred to as VMs QQ408), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer QQ406 may present a virtual operating platform that appears like networking hardware to the VMs QQ408.

[0216] The VMs QQ408 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer QQ406. Different embodiments of the instance of a virtual appliance QQ402 may be implemented on one or more of VMs QQ408, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment. In the context of NFV, a VM QQ408 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs QQ408, and that part of hardware QQ404 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs QQ408 on top of the hardware QQ404 and corresponds to the application QQ402.

[0217] Hardware QQ404 may be implemented in a standalone network node with generic or specific components. Hardware QQ404 may implement some functions via virtualization. Alternatively, hardware QQ404 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration QQ410, which, among others, oversees lifecycle management of applications QQ402. In some embodiments, hardware QQ404 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system QQ412 which may alternatively be used for communication between hardware nodes and radio units.

[0218] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non- computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0219] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0220] The present disclosure is described above with reference to the embodiments thereof. However, those embodiments are provided just for illustrative purpose, rather than limiting the present disclosure. The scope of the disclosure is defined by the attached claims as well as equivalents thereof. Those skilled in the art can make various alternations and modifications without departing from the scope of the disclosure, which all fall into the scope of the disclosure.

Claims

Claims1. A method (800) at a terminal device (100), the method (800) comprising: receiving (S810), from anetwork node (105), a first message indicating a configuration for on-demand reference signals associated with one or more secondary cells (SCells); and performing (S820) one or more operations associated with the on-demand reference signals based on at least the configuration.

2. The method (800) of claim 1, wherein the one or more operations comprise at least one of: synchronizing with at least one of the SCells in the time domain and / or in the frequency domain; measuring at least one of the on-demand reference signals; and activating at least one of the SCells.

3. The method (800) of claim 1 or 2, wherein the on-demand reference signals comprise on- demand Synchronous Signal (SS) and Physical Broadcast Channel (PBCH) blocks (SSBs).

4. The method (800) of any of claims 1 to 3, wherein the configuration is indicated by at least one of:- a Radio Resource Control (RRC) message;- a Medium Access Control (MAC) Control Element (CE); and- a Downlink Control Information (DCI).

5. The method (800) of any of claims 1 to 4, wherein when the configuration is indicated by a MAC CE, the MAC CE is at least one of:- an existing MAC CE for SCell activation or deactivation, which is extended to indicate the configuration;- a MAC CE for SCell activation or deactivation, which is defined separately from an existing MAC CE for SCell activation or deactivation; and- a MAC CE for indicating the configuration, which is able to be transmitted separately from a MAC CE for SCell activation or deactivation.

6. The method (800) of any of claims 1 to 5, wherein the configuration indicates, for at least one of the SCells, at least one of:- a first timing offset indicating when transmission of a corresponding on-demand reference signal is to be started;- a second timing offset indicating when transmission of a corresponding on-demand reference signal is to be stopped;- a duration, a timer, or a time window indicating for how long a transmission of corresponding on-demand reference signals can be expected;- an indicator indicating whether the terminal device (100), upon the reception of the first message, is to consider the configuration as activated or deactivated for the corresponding SCell;- a periodicity of a corresponding on-demand reference signal to be transmitted;- a periodicity of a corresponding on-demand reference signal burst to be transmitted;- a number of corresponding on-demand reference signal burst to be transmitted;- a Quasi-Co-Location (QCL) relation;- a timer for SCell deactivation;- a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst to be transmitted;- a reference cell;- a purpose of a corresponding on-demand reference signal; and- a transmission power.

7. The method (800) of claim 6, wherein at least one parameter indicated by the configuration is at least one of:- a parameter specific to an SCell;- a parameter specific to an SCell group; and- a parameter common to all the SCells.

8. The method (800) of any of claims 1 to 7, wherein the first message indicates one or more parameters in the configuration by at least one of:- directly comprising one or more parameters; and- indicating one or more parameters that are previously configured at the terminal device (100).

9. The method (800) of claim 8, wherein the one or more parameters that are previously configured at the terminal device (100) comprise at least one of:- a set of parameters, wherein one or more parameters in the set to be used by the terminal device (100) are indicated by the first message;- a set of configurations, wherein one of the configurations to be used by the terminal device (100) is indicated by the first message; and- multiple sets of parameters, wherein each set is associated with a purpose of on-demand reference signals, and wherein for at least one of the SCells indicated by the configuration, one of the multiple sets to be used by the terminal device (100) is indicated by the purpose of a corresponding on-demand reference signal associated with the corresponding SCell.

10. The method (800) of any of claims 1 to 9, wherein the configuration indicates that a first on-demand reference signal associated with a first of the SCells is used for measurement and that one or more second on-demand reference signals associated with one or more second SCells,which are intra-band contiguous, intra-band non-contiguous, or inter-band collocated with the first SCell, are used for SCell activation.

11. The method (800) of claim 10, wherein upon the reception of the first message, the terminal device (100) has no active serving cell that is intra-band contiguous, intra-band non-contiguous, or inter-band collocated with any of the SCells indicated by the configuration.

12. The method (800) of claim 10 or 11, wherein the configuration indicates one or more parameters such that a time length between the first on-demand reference signal and the earliest on-demand reference signal for SCell activation is longer than a pre-defined or configured time threshold.

13. The method (800) of any of claims 10 to 12, wherein the configuration indicates that the one or more second on-demand reference signals are Quasi-Co-Located (QCLed) with the first on- demand reference signal with a QCL type selected from a group comprising at least one of: QCL- typeA, QCL-typeB, QCL-typeC, and QCL-typeD.

14. The method (800) of any of claims 10 to 13, wherein the configuration indicates that the one or more second on-demand reference signals have a same time domain position in corresponding on-demand reference signal bursts as that of the first on-demand reference signal.

15. The method (800) of any of claims 1 to 14, wherein upon the reception of the first message, the terminal device (100) has an active serving cell that is intra-band contiguous, intra-band noncontiguous, or inter-band collocated with one or more third SCells indicated by the configuration.

16. The method (800) of claim 15, wherein the configuration indicates that one or more third on-demand reference signals associated with the one or more third SCells are used for SCell activation.

17. The method (800) of claim 15 or 16, wherein the configuration indicates that the one or more third on-demand reference signals have a same time domain position in corresponding on- demand reference signal bursts as that of a reference signal associated with the active serving cell in a corresponding reference signal burst.

18. The method (800) of any of claims 15 to 17, wherein the configuration indicates that the one or more third on-demand reference signals are QCLed with a reference signal associated with the active serving cell with a QCL type selected from a group comprising at least one of QCL- typeA, QCL-typeB, QCL-typeC, and QCL-typeD.

19. The method (800) of any of claims 1 to 18, wherein when the configuration indicates that multiple on-demand reference signals associated with multiple of the SCells are used for measurements, the configuration indicates one or more parameters such that multiple measurement periods, during which measurements of the multiple on-demand reference signals are performed, respectively, occur sequentially.

20. The method (800) of claim 19, wherein the configuration indicates one or more parameters such that a time length between an on-demand reference signal associated with an SCell for measurement and another on-demand reference signal associated with another SCell for measurement is longer than a time length of a measurement period.

21. The method (800) of claim 19 or 20, wherein an on-demand reference signal associated with an SCell for measurement has a measurement delay unless the SCell is at least one of:- an SCell that is contiguous to an active serving cell in the same band or to a known SCell in the same band;- an SCell for which a single on-demand reference signal is configured;- an SCell for which multiple on-demand reference signals are configured and a Transmission Configuration Indicator (TCI) is indicated by the configuration; and- an SCell for which a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst is same as that of a contiguous active serving cell in the same band or a contiguous known SCell in the same band.

22. The method (800) of any of claims 1 to 21, wherein one or more timing offsets are defined relative to at least one of:- the reception of the first message; and- a reference signal associated with a SCell different from the SCell for which the one or more timing offsets are defined.

23. The method (800) of any of claims 1 to 22, wherein when the configuration indicates that two or more on-demand reference signals associated with two or more SCells are QCLed with each other with a QCL TypeC, the two or more on-demand reference signals are QCLed directly or via a Tracking Reference Signal (TRS), and / or when the configuration indicates that one or more on-demand reference signals associated with one or more SCells are QCLed with a reference signal associated with an active serving cell with a QCL TypeC, the one or more on-demand reference signals are QCLed with the reference signal directly or via a TRS.

24. The method (800) of any of claims 1 to 23, wherein when the configuration indicates two or more transmission power associated with two or more on-demand reference signals, a difference between any two of the on-demand reference signals is less than a threshold power.

25. The method (800) of any of claims 1 to 24, wherein the configuration indicates a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the terminal device (100) is located closer to the SCell than the other SCell.

26. The method (800) of any of claims 1 to 25, wherein the configuration indicates a shorter timing offset for measurement in an SCell than that for measurement in another SCell when the SCell has a higher capability than the other SCell.

27. A terminal device (100, 1000) comprising: a processor (1006); a memory (1008) storing instructions which, when executed by the processor (1006), cause the terminal device (100, 1000) toany of the methods (800) of claims 2 to 26.

28. A method (900) at a network node (105), the method (900) comprising: transmitting (S910), to a terminal device (100), a first message indicating a configuration for on-demand reference signals associated with one or more SCells to trigger the terminal device (100) to perform one or more operations associated with the on-demand reference signals based on at least the configuration.

29. The method (900) of claim 28, wherein the one or more operations comprise at least one of: synchronizing with at least one of the SCells in the time domain and / or in the frequency domain; measuring at least one of the on-demand reference signals; and activating at least one of the SCells.

30. The method (900) of claim 28 or 29, wherein the on-demand reference signals comprise on-demand SSBs.

31. The method (900) of any of claims 28 to 30, wherein the configuration is indicated by at least one of:- an RRC message;- a MAC CE; and- a DCI.

32. The method (900) of any of claims 28 to 31, wherein when the configuration is indicated by a MAC CE, the MAC CE is at least one of:- an existing MAC CE for SCell activation or deactivation, which is extended to indicate the configuration;- a MAC CE for SCell activation or deactivation, which is defined separately from an existing MAC CE for SCell activation or deactivation; and- a MAC CE for indicating the configuration, which is able to be transmitted separately from a MAC CE for SCell activation or deactivation.

33. The method (900) of any of claims 8 to 32, wherein the configuration indicates, for at least one of the SCells, at least one of:- a first timing offset indicating when transmission of a corresponding on-demand reference signal is to be started;- a second timing offset indicating when transmission of a corresponding on-demand reference signal is to be stopped;- a duration, a timer, or a time window indicating for how long a transmission of corresponding on-demand reference signals can be expected;- an indicator indicating whether the terminal device (100), upon the reception of the first message, is to consider the configuration as activated or deactivated for the corresponding SCell;- a periodicity of a corresponding on-demand reference signal to be transmitted;- a periodicity of a corresponding on-demand reference signal burst to be transmitted;- a number of corresponding on-demand reference signal burst to be transmitted;- a Quasi-Co-Location (QCL) relation;- a timer for SCell deactivation;- a time domain position of a corresponding on-demand reference signal in a corresponding on-demand reference signal burst to be transmitted;- a reference cell;- a purpose of a corresponding on-demand reference signal; and- a transmission power.

34. The method (900) of claim 33, wherein at least one parameter indicated by the configuration is at least one of:- a parameter specific to an SCell;- a parameter specific to an SCell group; and- a parameter common to all the SCells.

35. The method (900) of any of claims 28 to 34, wherein the first message indicates one or more parameters in the configuration by at least one of:- directly comprising one or more parameters; and- indicating one or more parameters that are previously configured at the terminal device (100).

36. The method (900) of claim 35, wherein the one or more parameters that are previously configured at the terminal device (100) comprise at least one of:- a set of parameters, wherein one or more parameters in the set to be used by the terminal device (100) are indicated by the first message;- a set of configurations, wherein one of the configurations to be used by the terminal device (100) is indicated by the first message; and- multiple sets of parameters, wherein each set is associated with a purpose of on-demand reference signals, and wherein for at least one of the SCells indicated by the configuration, one of the multiple sets to be used by the terminal device (100) is indicated by the purpose of a corresponding on-demand reference signal associated with the corresponding SCell.

37. The method (900) of any of claims 28 to 36, wherein the configuration indicates that a first on-demand reference signal associated with a first of the SCells is used for measurement and that one or more second on-demand reference signals associated with one or more second SCells, which are intra-band contiguous, intra-band non-contiguous, or inter-band collocated with the first SCell, are used for SCell activation.

38. A network node (105, 1000) comprising: a processor (1006); a memory (1008) storing instructions which, when executed by the processor (1006), cause the network node (105, 1000) to perform any of the methods (900) of claims 30 to 54.

39. A computer program (1010) comprising instructions which, when executed by at least one processor (1006), cause the at least one processor (1006) to carry out the method (800, 900) of any of claims 1 to 26 and 28 to 37.

40. A telecommunication system (10), comprising: one or more terminal devices (100) of claim 27; and a network node (105) of claim 38.

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