Activation / de-activation indication for TRS resources

Abstract

Embodiments of the present disclosure relate to an activation / de-activation indication for one or more resources of a tracking reference signal (TRS) resource. In one aspect, a terminal device receives an activation / de-activation indication for at least one resource group with at least one antenna port for a TRS resource from a network device. Based on the activation / de-activation indication, the terminal device activates or de-activates the at least one resource group with the at least one antenna port.

Description

ACTIVATION / DE-ACTIVATION INDICATION FOR TRS RESOURCESCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority from US Provisional Application No. 63 / 729790, filed December 9, 2024, which is hereby incorporated by reference in its entirety.FIELD

[0002] Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and a computer readable storage medium for an activation / de-activation indication for one or more resources of a tracking reference signal (TRS).BACKGROUND

[0003] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0004] Such communication networks operate in accordance with standards, such as those promulgated by Third Generation Partnership Project (3GPP) or European Telecommunications Standards Institute (ETSI). Examples of such standards include the so-called 5th generation (5G) standard, 6th generation (6G) or other standards promulgated by 3GPP.SUMMARY

[0005] In general, example embodiments of the present disclosure provide a solution for an activation / de- activation indication for one or more resources of a TRS.

[0006] In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a network device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource, and activate or de-activate, based on the activation / de-activation indication, the at least one resource group with one more resources with the at least one antenna port.

[0007] In a second aspect, there is provided a network device. The network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit, to a terminal device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource.

[0008] In a third aspect, there is provided a method. The method comprises receiving, at a terminal device and from a network device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource, and activating or de-activating, based on the activation / de-activation indication, the at least one resource group with one more resources with the atleast one antenna port.

[0009] In a fourth aspect, there is provided a method. The method comprises transmitting, at a network device and to a terminal device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource.

[0010] In a fifth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a terminal device and from a network device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource, and means for activating or de-activating, based on the activation / de-activation indication, the at least one resource group with one more resources with the at least one antenna port.

[0011] In a sixth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a network device and to a terminal device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource.

[0012] In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above third to fourth aspect.

[0013] In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to any one of the above third to fourth aspect.

[0014] In a ninth aspect, there is provided a terminal device. The terminal device comprises receiving circuitry configured to receive, from a network device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource, and activating or de-activating circuitry configured to activate or de-activate, based on the activation / de-activation indication, the at least one resource group with one more resources with the at least one antenna port.

[0015] In a tenth aspect, there is provided a network device. The network device comprises transmitting circuitry configured to transmit, to a terminal device, an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource.

[0016] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0018] Fig. 1 A illustrates an example network environment in which example embodiments of the present disclosure may be implemented;

[0019] Fig. 1 B illustrates an example of a non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource configuration for 48 antenna ports (APs);

[0020] Fig. 1 C illustrates an example of an NZP CSI-RS resource configuration for 64-APs;

[0021] Fig. 1 D illustrates an example of an NZP CSI-RS resource configuration for 128-APs;

[0022] Fig. 1 E illustrates an example of different TRS configurations for FR1 and FR2 supported by NR;

[0023] Fig. 2 illustrates an example signaling chart illustrating an example process according to some embodiments of the present disclosure;

[0024] Fig. 3 illustrates an example of activation and de-activation of NZP-CSI-RS resource set and resources for TRS;

[0025] Fig. 4A illustrates an example of activation and de-activation of NZP-CSI-RS resource set and resources for TRS before receiving a medium access control control element (MAC CE);

[0026] Fig. 4B illustrates an example of activation and de-activation of NZP-CSI-RS resource set and resources for TRS after receiving a MAC CE;

[0027] Fig. 5 illustrates an example process according to some embodiments of the present disclosure;

[0028] Fig. 6 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

[0029] Fig. 7 illustrates a flowchart of a method implemented at a network device according to some example embodiments of the present disclosure;

[0030] Fig. 8 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

[0031] Fig. 9 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

[0032] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0033] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement example embodiments of the present disclosure, without suggesting any limitation as to the scope of the disclosure. The example embodiments of the present disclosure described herein can be implemented in various manners other than the ones described below.

[0034] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0035] References in the present disclosure to “one embodiment,” “an embodiment,” “an exampleembodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0036] It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0038] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0039] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merelya hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0040] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as long term evolution (LTE), LTE-advanced (LTE-A), wideband code division multiple access (WCDMA), high-speed packet access (HSPA), narrow band internet of things (NB- loT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1 G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which example embodiments of the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0041] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a new radio (NR) NB (also referred to as a gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0042] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehiclemounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an internet of things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chaincontexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0043] Fig. 1A illustrates an example network environment 100 in which example embodiments of the present disclosure may be implemented. The environment or communication system 100, which may be a part of a communication network, comprises terminal devices and network devices.

[0044] As illustrated in Fig. 1A, the communication network 100 may comprise a terminal device 110 (hereinafter may also be referred to as user equipment 110 or a UE 110). The communication network 100 may further comprise a network device 120. The network device 120 can manage a cell 101. The terminal device 110 and the network device 120 can communicate with each other in the coverage of the cell 101. A link from the terminal device 110 to the network device 120 is referred to as an uplink (UL), while a link from the network device 120 to the terminal device 110 is referred to as a downlink (DL).

[0045] It is to be understood that the number of devices is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of terminal devices or network devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices or network devices may be located in the system 100.

[0046] Communications in the communication system 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1 G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiple (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0047] Current Release (Rel) 18 NR specification supports up to 32 ports for a CSI-RS resource, which is a bottleneck for deployment of large antenna arrays. As per the description in Rel-19 Multiple-Input Multiple- Output (MIMO) work item (Wl) will support to increase the port number up to 128, but there is no specification support from 32 to 128 antenna ports per single NZP-CSI-RS resource. By leveraging NZP-CSI-RS design with e.g. 24, 32 antenna ports, some typical port numbers that can be considered, e.g., 48, 64,128 by aggregating multiple resources. Considering difference on possible deployment scenarios and gNB antenna implementations, all those port numbers can be considered.

[0048] The following agreement was made regarding to support NZP-CSI-RS configurations for higher number of antenna ports. For the Rel-19 Type-1 and Type-11 codebook refinement for 48, 64, and 128 CSI- RS ports, regarding NZP CSI-RS resource aggregation to attain 32 < P (or PCSI-RS) 128, the following refinement on the K>1 CSI-RS resources associated with a same CSI-RS resource set is supported. Perresource configuration of evenPRBs or oddPRBs for 0.5 RE / RB / port density is allowed. For AP-CSI-RS, a resource-specific slot offset is allowed when the K NZP CSI-RS resources are located in two consecutive slots. The details on how to configure / determine the slot offsets is to be further studied.

[0049] In other words, within an NZP-CSI-RS resource set, multiple NZP-CSI-RS resources may be aggregated to support 48, 64 and 128 APs, where NZP-CSI-RS resources share the same starting physical resource block (PRB) and each resource within the resource set may be configured either to even PRB or odd PRBs with 0.5 RE / PRB / port density.

[0050] For the Rel-19 Type-I and Type-ll codebook refinement for 48, 64, and 128 CSI-RS ports, regarding aggregation of K NZP CSI-RS resources to attain 32 < P (or PCSI-RS) 128, only the following combinations of K and P (or PCSI-RS) are supported. For P (or PCSI-RS) = 48, K = 2 (each resource 24 ports) and 3 (each resource 16 ports). For P (or PCSI-RS) = 64, K = 2 (each resource 32 ports) and 4 (each resource 16 ports). For P (or PCSI-RS) = 128, K = 4 (each resource 32 ports).

[0051] As shown in Fig. 1 B, two resources with 24 ports may be aggregated for 48 APs, and three resources with 16 ports may also be aggregated for 48 APs. As shown in Fig. 1 C, two resources with 32 ports may be aggregated for 64 APs, and four resources with 16 ports may also be aggregated for 64 APs.

[0052] The support for antenna ports up to 128 APs may be obtained by aggregation of different number of NZP-CSI-RS resources. For example, four resources with 32 ports may also be aggregated for 128 APs as shown in Fig. 1 D.

[0053] For 6G, to support higher spectral efficiencies (e.g. enhanced multi-user (MU) MIMO) and enhanced the coverage in both UL and DL, even larger antenna arrays needs to be supported with larger number of physical antenna elements and corresponding logical antenna ports, e.g. up to 256 or 512 logical antenna ports. As a result of this, DL NZP-CSI-RS resource configurations need to support even higher number of antenna ports (>128 APs) with 6G carrier frequencies (e.g., 6.425-7.125 GHz and / or 7.125 -15 GHz).

[0054] NR provides support to set the channel estimator parameters properly for the reception of the demodulation reference signal (DMRS) of physical dedicated control channel (PDCCH), DMRS of physical dedicated data channel (PDSCH) and NZP-CSI-RS by configuring the UE with periodic time and the NZP- CSI-RS based time and frequency TRS in NR. The TRS is a UE specific signal and basically mandatory periodic reference signal to be transmitted for each connected mode UE. The network may share the same configuration to multiple UEs with a service area (e.g. a cell / sector).

[0055] The TRS enables the UE to perform the optimization of different parameters related to a channelestimator, e.g. for DMRS the length of 2-D Wiener filter in a frequency and time. The TRS may be configured by using one or two NZP-CSI-RS resource set with two or four one antenna port NZP-CSI-RS resources with the following parameters. For FR1, a TRS burst length may be two consecutive downlink slots valid and for FR2, the TRS burst length may be one or two consecutive valid downlink slots. In each TRS slot, there are two TRS symbols. TRS symbols in the slot are having four symbol separation in time. TRS burst periodicity can be either 10, 20, 40 or 80 ms. As shown in Fig. 1 E, FR2 may have one or two slots, and a notation of {4,8} defines a pair of TRS symbols located in the 4th and 8th symbol positions in a slot.

[0056] The UE may be configured with multiple TRS configurations to receive the TRS and keep tracking time and frequency domain parameters for the channel estimators, e.g. from different transmission points (TRP) / TX beams according to associated TCI state. As said TRS is periodical and UE specific, i.e. TRS is configured separately for each UE. There can be additional aperiodic TRS but it may be always associated with periodical TRS.

[0057] A UE configured with NZP-CSI-RS-ResourceSet(s) configured with higher layer parameter trs-lnfo may have the CSI-RS resources configured as periodic, with the CSI-RS resources in the NZP-CSI-RS- ResourceSet configured with same periodicity, bandwidth and subcarrier location. Alternatively, the UE may have the CSI-RS resources configured as periodic CSI-RS resource in one set and aperiodic CSI-RS resources in a second set, with the aperiodic CSI-RS and periodic CSI-RS resource having the same bandwidth (with same RB location) and the aperiodic CSI-RS being configured with qcl-Type set to “typeA” and “typed”, where applicable, with the periodic CSI-RS resources.

[0058] Some example embodiments of the present disclosure are related to 3GPP 6G physical layer design, and focus on facilitating support for a dynamic 6G time-and frequency tracking reference signal configuration with reduced resource overhead and enhance energy efficiency with a large number of antenna ports (AP)s (e.g. >128 APs) associated with the NZP CSI-RS.

[0059] In 5G new radio, periodic / semi-persistent / aperiodic NZP-CSI-RS resource set(s) and resources therein are assumed to be configured and reconfigured with an RRC signaling. Typically, the RRC signaling is a rather time consuming operation, i.e. order of tens of milliseconds. Furthermore, it can be also inefficient in terms of associated resource overhead.

[0060] Improved energy efficiency and enhanced multi-TRP operations are one of key drivers for a 6G system design. To support this design target, NZP-CSI-RS resource configurations for time-and frequency tracking and DL CSI acquisition with higher number of antenna ports (>128) need to have a support for enhanced adaptability with reduced resource overhead. 5G NR supports a MAC CE based activation / de- activation for semi-persistent NZP-CSI-RS and CSI-IM resources sets. To use this in 6G, this requires that the UE is configured via an RRC signaling with a large number of different resource sets with a specific number of resources therein. Then, the network may activate / de-activate one semi-persistent NZP-CSI-RS RS set via a MAC CE at the time with all resources therein allowing adaptability only at a resource set levelleaving out support for adaptation more finer granularity manner. Therefore, it does not provide support for energy efficient network as well as UE operation. Furthermore, it requires an extra RRC signaling (i.e. reconfiguration) level before even indicating any activation / de-activation commands for the UE leading a problems resource overhead.

[0061] According to some embodiments of the present disclosure, a solution is provided for an activation / de-activation indication for one or more resources of a TRS. In one aspect of this solution, a terminal device receives an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource from a network device. Based on the activation / de-activation indication, the terminal device activates or de-activates the at least one resource group with one more resources with the at least one antenna port. In this way, enhanced signaling methods and UE procedures are provided. Therefore, more energy efficient and reduced signaling overhead operation in 6G are enabled. Principles and implementations of embodiments of the present disclosure will be described in detail below with reference to Figs. 2-9.

[0062] Fig. 2 illustrates a signaling chart illustrating an example process 200 according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1A. The process 200 may involve the terminal device 110, and the network device 120. The network device 120 may also be referred to as a first network device, and the network device 130 may also be referred to as a second network device hereinafter. It would be appreciated that although the process 200 has been described in relation to the communication system 100 of Fig. 1 A, this process may be likewise applied to other communication scenarios with similar issues.

[0063] In the process 200, the network device 120 transmits 210 an activation / de-activation indication for at least one resource group with one more resources with at least one antenna port for a TRS resource 215 to the terminal device 110. Additionally, the at least one resource group may be associated with one more resources with at least one resource set . For example, the at least one resource group with one more resources may be comprised in the at least one resource set. As shown in Fig. 3, NZP-CSI-RS resource set#1 is a resource set, and the resources CRI#9-12 are compose a resource group comprised in the NZP- CSI-RS resource set#1.

[0064] In some embodiments, the at least one resource set may comprise at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource. In some embodiments, the at least one resource set may be for the TRS and downlink (DL) CSI acquisition. In some embodiments, the at least one resource group with one more resources may be for the TRS.

[0065] In an example, the terminal device 110 may be dynamically indicated with one or more activated antenna port IDs (each ID of M-antenna port IDs) associated with one or more M-antenna port semi-persistent NZP-CSI-RS resources (i.e. resource group) for time-and-frequency tracking with a MAC CE associated with a serving or non-serving cell. Activated M-antenna port resources may be associated with one or moreNZP-CSI-RS resource sets for time-and frequency tracking as well as DL CSI acquisition. As shown in Fig. 3, AP ID#0 with resources, i.e. CRI#14-16, is indicated to the terminal device 110, and same 1 -antenna port indicated by AP ID#0 is associated with a resource group composed of resources CRI#14-16 in NZP-CSI- RS resource set#0. The NZP-CSI-RS resource set#0 is for the time-and frequency tracking as well as the DL CSI acquisition, and 8 different 32-AP resources are for the DL CSI acquisition.

[0066] In another example, the terminal device 110 may be dynamically indicated one or more de-activated M-antenna port associated with semi-persistent NZP-CSI- resources for time-and-frequency tracking with a MAC CE associated with a serving or non-serving cell. De-activated M-antenna port resources may be associated with one or more NZP-CSI-RS resource sets for time-and frequency tracking as well as DL CSI acquisition. As shown in Fig. 3, 2-antenna ports associated with a resource group composed of resources CRI#9-12 in NZP-CSI-RS resource set#1 are indicated to be de-activated. The de-activated resource group is associated with the NZP-CSI-RS resource set#1 . The NZP-CSI-RS resource set#1 is for the time-and frequency tracking as well as the DL CSI acquisition, and 8 different 32-AP resources are for the DL CSI acquisition.

[0067] In some embodiments, the activation / de-activation indication may comprise a list of at least one identity (ID) of the at least one resource set associated with serving or non-serving cell to be activated, a list of at least one ID of the at least one resource to be activated, a list of at least one ID of at least one antenna port associated with the at least one resource to be activated, a list of at least one ID of the at least one resource set associated with serving or non-serving cell to be de-activated, a list of at least one ID of the at least one resource to be de-activated, a list of at least one ID of at least one antenna port associated with the at least one resource to be de-activated, or any combination of two or more of the above-mentioned items. Additionally, In some embodiments, the activation / de-activation indication may be received via a MAC CE.

[0068] In one additional embodiment, it is possible that activation command consists of only resource set IDs associated with serving or non-serving cells and resource IDs and antenna port IDs to be activated. Similarly, it is possible that the de-activation command consists of only resource set IDs associated with serving or non-serving cells and resource IDs and antenna port IDs to be de-activated.

[0069] For example, the semi-persistent time-and frequency tracking MAC CE activation and / or deactivation command with one or more activated APs may be defined, and the MAC CE may include some information elements. For example, the information elements may include a list of activated NZP-CSI-RS resource set IDs associated with one or more groups of activated NZP-CSI-RS resource IDs with one or more groups of activated AP IDs for time-and frequency tracking, or a list of de-activated NZP-CSI-RS resource set IDs with group(s) of de-activated NZP-CSI-RS resource IDs for time-and frequency tracking.

[0070] Alternatively or additionally, an ID of a resource set in the list may be associated with one or more groups of IDs of resources in the at least one resource group. In addition, an ID of a resource set in the listmay be associated with an ID of a cell to which the activation / de-activation indication is applied. In some embodiments, the ID of the cell may comprise a serving cell physical ID or a non-serving cell physical ID. In an example, each activated NZP-CSI-RS resource set ID in the list is associated with a cell ID which indicates the identity of the cell for which the MAC CE applies, it can be either a serving cell physical ID or a nonserving cell physical ID. In another example, each de-activated resource set ID is associated with a cell ID which indicates the identity of the cell for which the MAC CE applies, it can be either a serving cell physical ID or non-serving cell physical ID.

[0071] Additionally, a group of IDs of resources in the at least one resource group may be associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group. For example, each group of activated NZP-CSI-RS resource IDs is associated with a group of TCI state IDs. Each TCI state ID of a TCI State is used as QCL source for the NZP-CSI-RS resource.

[0072] Regarding the association between the group of IDs of resources and the group of IDs of TCI states, the group of IDs of resources may be mapped to an ID of a TCI state in the group of IDs of the TCI states. Alternatively, an ID of a resource in the group may be mapped to an ID of a TCI state in the group of IDs of the TCI states.

[0073] For instance, the mapping between group NZP-CSI-RS resource IDs with a group of TCIs may be resource-group-ID-level or resource-1 D-level. For the resource-group-ID-level, one group of resource IDs may be mapped to one TCI state ID. In other words, all resources within a resource group share a same TCI state ID. For the resource-1 D-level, resource IDs within one group of resource IDs are mapped with different TCI-State IDs within a group of TCI state IDs.

[0074] In addition, a group of IDs of resources in the at least one resource group may be associated with one or more IDs of one or more antenna ports. For example, each group of activated resource IDs may be associated with one activated antenna ports ID (i.e. one-to-one mapping) in the list of activated antenna port IDs.

[0075] Regarding the association between the group of IDs of resources and the one or more IDs of one or more antenna ports, multiple groups of IDs of resources in the at least one resource group may be mapped to IDs of antenna ports in an ascending order. For example, the first AP ID in the list is mapped to the first activated resource group, and the second AP ID is mapped to the second activated resource group.

[0076] In some embodiments, the terminal device 110 may transmits capability information to the network device 120 for a dynamic indication of at least one resource for the TRS associated with at least one resource set. Correspondingly, the network device 120 may receive network device 120 from the terminal device 110.

[0077] Alternatively or additionally, the capability information may comprise a maximum number of the at least one resource set for the TRS that are simultaneously activated, a maximum number of one or more resources per resource set for the TRS that are simultaneously activated, or a combination of the above-mentioned items.

[0078] For instance, the capability information transmitted via a UE capability signaling for dynamic indication of TRS resources associated with one or more resource sets may be defined. The capability signaling may cover some information elements, such as, the maximum number of activated NZP-CSI-RS resource sets for TRS associated with a serving and non-serving cells, or the maximum number of activated NZP-CSI-RS resources for per resource set for TRS associated with a serving and non-serving cells that are simultaneously active for time and frequency tracking purposes.

[0079] The maximum number of activated NZP-CSI-RS resource sets refers to the maximum number of different NZP-CSI-RS resource sets that are simultaneously active. The term “active” here means that the terminal device 110 is assumed to have capability to perform channel estimation and related CSI computation and potential reporting based on these resources. For instance, the NZP-CSI-RS resource sets include NZP- CSI-RS resources with one or antenna ports based which the terminal device 110 may compute channel estimates based on which phase difference and frequency offset are computed. The NZP-CSI-RS resource sets have both time-and frequency tracking resources as well as DL CSI acquisition resources.

[0080] Continuing with reference to Fig. 2, the terminal device 110 receives 220 the activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for the TRS resource 215 from the network device 120. Based on the activation / de-activation indication, the terminal device 110 activate or de-activate 225 the at least one resource group with one or more resources with the at least one antenna port.

[0081] In some embodiments, based on at least one ID of the at least one antenna port, the terminal device 110 may determine at least one antenna port pair between resources with a same ID of an antenna port in a resource group.

[0082] In an example, upon the reception of semi-persistent time-and frequency tracking MAC CE command with a list of activated NZP-CSI-RS resource set IDs and one or more groups of activated M- antenna port NZP-CSI-RS resource IDs as well as with one or more activated antenna port IDs, the terminal device 110 may activate one or more indicated antenna ports (e.g., with indicated AP IDs) with one or more groups of activated NZP-CSI-RS resource groups with an activated resource set list.

[0083] Alternatively or additionally, based on the at least one antenna port pair, the terminal device 110 may determine at least one antenna port channel estimate.

[0084] In addition, the terminal device 110 may determine an estimate of a phase difference between the antenna port channel estimates within an antenna port pair.

[0085] Additionally, the terminal device 110 may determine an aggregated estimate of a phase difference based on at least one estimate of phase difference of the at least one antenna port pair.

[0086] Additionally, the terminal device 110 may determine a frequency offset per resource group to be applied for a physical downlink shared channel (PDSCH) demodulation reference signal (DMRS) and aPDSCH as well as for a physical uplink shared channel (PUSCH) DMRS and a PUSCH.

[0087] In an example, for each group of activated M-antenna port NZP-CSI-RS resources, the terminal device 110 may use an indicated AP ID out of M-antenna ports to determine antenna port pairs between M- antenna port NZP-CSI resources with same AP ID. Based on the determined antenna port pairs, the terminal device 110 may compute corresponding AP specific channel estimates over frequency resources assigned for each resource. Then, the terminal device 110 may compute estimates of phase difference between antenna port specific channel estimates within an antenna port pair and determine a frequency offset to be applied for PDSCH DMRS and PDSCH as well as for PUSCH DMRS, PUSCH.

[0088] It is to be noted that “active ( or activation)” here means that the terminal device 110 may start performing channel estimation for time-and frequency tracking based indicated antenna port(s) associated with indicated resources as well as resource sets until it receives de-activation time-and frequency tracking MAC CE command.

[0089] In another example, upon the reception of semi-persistent time-and frequency tracking MAC CE command with a list of de-activated NZP-CSI-RS resource set IDs and one or more groups of de-activated M-antenna port NZP-CSI-RS resource IDs, the terminal device 110 may de-activate all antenna ports associated with one or more groups of de-activated NZP-CSI-RS resource groups with a de-activated resource set list.

[0090] It is to be noted that “de-active (or de-activation)” here means that the terminal device 110 may stop performing of channel estimations for time-and frequency tracking based indicated antenna port(s) associated with indicated resources as well as resource sets until it receives activation time-and frequency tracking MAC CE command.

[0091] With the solution of an activation / de-activation indication for one or more resources of a TRS, dynamic activation / De-activation enables time-and frequency tracking resources and antenna ports to be adjusted such that energy efficiency of a system can be optimized. As a result of overhead reduction, overall system performance (both sector and user) are improved.

[0092] Fig. 3 illustrates an example of activation and de-activation of NZP-CSI-RS resource set and group of resources for time-and frequency tracking in conjunction with resources for DL CSI acquisition. The UE is configured, e.g. via an RRC signaling, with three different semi-persistent NZP-CSI-RS resource sets (e.g., NZP-CSI-RS set #0, NZP-CSI-RS set #1 , NZP-CSI-RS set #2) with semi-persistent NZP-CSI-RS resources with different antenna ports for time-and frequency tracking as well as DL CSI acquisition with 32-AP resources.

[0093] As shown in Fig. 3, the NZP-CSI-RS set#1 is configured with 8 different 2-AP NZP-CSI-RS resources and 8 different 32-AP NZP-CSI-RS resources. Furthermore, the NZP-CSI-RS set#0 is configured with 8 different 1-AP NZP-CSI-RS resources and 8 different 32-AP NZP-CSI-RS resources as well as the NZP-CSI-RS set#2 with 8 different 4-AP NZP-CSI-RS resources and 8 different 32-AP NZP-CSI-RSresources. Initially, one configured semi-persistent NZP-CSI-RS resource set is activated (i.e., NZP-CSI-RS resource set#1) with 4 different 2-AP resources and remaining two semi-persistent NZP-CSI-RS resource sets#0 and #2 are de-activated.

[0094] As a first, the network sends the time-and frequency resource MAC CE de-activation command via the PDSCH for the UE to de-activate semi-persistent group of four 2-AP resource IDs, i.e. CRI#9-12, associated with de-activated resource set ID list, i.e. resource set#1. Upon the reception of the MAC deactivation command, the UE de-activates NZP-CSI-RS resource set#1 and resources CRI#9-12 therein. Based on the command, the UE stops performing channel estimation for time-and frequency tracking based on indicated de-activated resources as well as resource sets.

[0095] After this, the network sends the time-and frequency resource MAC CE activation command via PDSCH for the UE to activate semi-persistent group of four 1-AP resources, i.e. CRI#13-16, with activated antenna port ID #0 associated with the active resource set ID list, i.e. source set#O, with 4 different 1-AP resources. Upon reception of the MAC CE activation command, the UE activates activated antenna port ID (#0) from 1-AP NZP-CSI-RS resources for time-and frequency tracking purposes.

[0096] Fig. 4A illustrates an example of activation and de-activation of NZP-CSI-RS resource sets and resources for time-and frequency tracking with joint resource set configuration with DL CSI acquisition with higher number of antenna ports (256-APs) before receiving a MAC CE.

[0097] As shown in Fig. 4A, there are 2 constructive slots, 8 2-AP resources and 4 AP Pairs per slot. The CDM-4 refers a CDM with 4 REs. The result when MAC CE is sent to activate new resource set and resources therein is shown in Fig. 4B. After the activation of of 1-AP resources within resource set#O and the deactivation of 2-AP resources within resource set#1 , the 8 2-AP resources are de-activated and 16 1-AP resources are activated.

[0098] Fig. 5 illustrates an example process of proposed solution according to some embodiments of the present disclosure. The process 500 may involve a gNB 501 and a UE 502. It is understood that the process500 can be considered as a more specific example of process 200. Thus, the gNB 501 of Fig. 5 may represent for example the network device 120 of Fig. 2, the UE 502 of Fig. 5 may represent for example the terminal device 110 of Fig. 2.

[0099] In the process 500, at 510, the UE 502 transmits a capability signaling to the gNB 501. The capability signaling is about the maximum number of active NZP-CSI-RS resource sets and resources for the TRS and the DL CSI acquisition. At 515, the gNB 501 configure one or more semi-persistent NZP-CSI- RS resource sets for time and frequency tracking and DL CSI acquisition for the UE 502. At 520, the gNB501 transmits a time and frequency tracking MAC CE to the UE 502 via the PDSCH to activate a list of NZP- CSI-RS resource sets and one more groups of M-AP NZP-CSI-RS resources with one or more active antenna ports for the TRS and the DL CSI acquisition.

[0100] At 525, the UE 502 activates indicated antenna ports with one or more groups of M-AP NZP-CSI-RS resources with NZP-CSI-RS resource sets) for the TRS. At 530, the gNB 501 starts transmissions of activated semi-persistent M-AP NZP-CSI-RS resources within activated resource set for the TRS and the DL CSI acquisition with a high number of APs. At 535, the gNB 501 performs transmissions of semi-persistent NZP CSI RS resources for the TRS and time and frequency tracking continues in time with activated AP(s).

[0101] At 540, for each resource group, the UE 502 determines AP pairs by using indicated activated AP ID(s). At 545, for each AP pair, the UE 502 determines AP specific channel estimates and relative phase shifts associated with activated NZP CSI resources for TRS and DL CSI acquisition. At 550, the UE 502 aggregates relative phase offsets over multiple AP pairs within the resource group and determine phase offset value associated with the resource group. At 555, the UE 502 determines frequency offset per resource group and applies it to any potential DL / UL data / RS / control transmission.

[0102] At 560, the gNB 501 transmits a MAC CE to the UE 502 via the PDSCH to de-activate a list of NZP CSI RS resource sets and one or more groups of M-AP NZP CSI RS resources with one or more active antenna ports for TRS and DL CSI acquisition. At 565, the gNB 501 stops the transmission of de-activated semi-persistent M-AP NZP-CSI -resources within de-activated resource set for TRS and DL CSI acquisition with high number of APs. At 570, the UE 502 stops performing channel estimation for time- and frequency tracking based on indicated de-activated resources as well as resource sets.

[0103] Fig. 6 shows a flowchart of an example method 600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 with reference to Fig. 1A.

[0104] At block 610, the terminal device 110 receives, from a network device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource. At block 620, the terminal device 110 activates or de-activates, based on the activation / de-activation indication, the at least one resource group with one or more resources with the at least one antenna port.

[0105] In some embodiments, the at least one resource group may be associated with at least one resource set. In some embodiments, the activation / de-activation indication may comprise at least one of the following: a list of at least one identity (ID) of the at least one resource set to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated; a list of at least one ID of at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the at least one resource group to be de-activated.

[0106] In some embodiments, an ID of a resource set in the list may be associated with an ID of a cell to which the activation / de-activation indication is applied. In some embodiments, an ID of a resource set in the list may be associated with one or more groups of IDs of resources in the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated witha group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with one or more IDs of one or more antenna ports.

[0107] In some embodiments, the group of IDs of resources may be mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group may be mapped to an ID of a TCI state in the group of IDs of the TCI states.

[0108] In some embodiments, multiple groups of IDs of resources in the at least one resource group may be mapped to IDs of antenna ports in an ascending order. In some embodiments, the terminal device 110 may transmit, to the network device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

[0109] In some embodiments, the capability information may comprise at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for the TRS that are simultaneously activated.

[0110] In some embodiments, the terminal device 110 may further determine, based on at least one ID of the at least one antenna port, at least one antenna port pair between resources with a same ID of an antenna port in a resource group.

[0111] In some embodiments, the terminal device 110 may further determine at least one antenna port channel estimate based on the at least one antenna port pair. In some embodiments, the terminal device 110 may further determine an estimate of a phase difference between the antenna port channel estimates within an antenna port pair.

[0112] In some embodiments, the terminal device 110 may further determine an aggregated estimate of a phase difference based on at least one estimate of phase difference of the at least one antenna port pair.

[0113] In some embodiments, the terminal device 110 may further determine a frequency offset per resource group to be applied for a physical downlink shared channel (PDSCH) demodulation reference signal (DMRS) and a PDSCH as well as for a physical uplink shared channel (PUSCH) DMRS and a PUSCH.

[0114] In some embodiments, the activation / de-activation indication may be received via a medium access control control element (MAC CE). In some embodiments, the ID of the cell may comprise one of a serving cell physical ID or a non-serving cell physical ID. In some embodiments, the at least one resource set may comprise at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource. In some embodiments, the at least one resource set may be for the TRS and downlink (DL) CSI acquisition. In some embodiments, the at least one resource group may be for the TRS.

[0115] Fig. 7 shows a flowchart of an example method 700 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the network device 120 with reference to Fig. 1A.

[0116] At block 710, the network device 120 transmits, to a terminal device, an activation / de-activationindication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource.

[0117] In some embodiments, the at least one resource group may be associated with at least one resource set. In some embodiments, the activation / de-activation indication may comprise at least one of the following: a list of at least one identity (ID) of the at least one resource set associated with serving or nonserving cell to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated; a list of at least one ID of at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the at least one resource group to be de-activated.

[0118] In some embodiments, an ID of a resource set in the list may be associated with an ID of a cell to which the activation / de-activation indication is applied. In some embodiments, an ID of a resource set in the list may be associated with one or more groups of IDs of resources in the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with one or more IDs of one or more antenna ports.

[0119] In some embodiments, the group of IDs of resources may be mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group may be mapped to an ID of a TCI state in the group of IDs of the TCI states.

[0120] In some embodiments, multiple groups of IDs of resources in the at least one resource group may be mapped to IDs of antenna ports in an ascending order. In some embodiments, the network device 120 may receive, from the terminal device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

[0121] In some embodiments, the capability information may comprise at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for the TRS that are simultaneously activated.

[0122] In some embodiments, the activation / de-activation indication may be received via a medium access control control element (MAC CE). In some embodiments, the ID of the cell may comprise one of a serving cell physical ID or a non-serving cell physical ID. In some embodiments, the at least one resource set may comprise at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource. In some embodiments, the at least one resource set may be for the TRS and downlink (DL) CSI acquisition. In some embodiments, the at least one resource group may be for the TRS.

[0123] In some embodiments, an apparatus capable of performing any of the method 600 (for example, the terminal device 110) is provided. The apparatus may comprise means for performing the respective stepsof the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0124] In some embodiments, the apparatus comprises means for receiving, from a network device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource; and means for activating or de-activating, based on the activation / de-activation indication, the at least one resource group with one or more resources with the at least one antenna port.

[0125] In some embodiments, the at least one resource group may be associated with at least one resource set. In some embodiments, the activation / de-activation indication may comprise at least one of the following: a list of at least one identity (ID) of the at least one resource set associated with serving or nonserving cell to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated; a list of at least one ID of at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the at least one resource group to be de-activated.

[0126] In some embodiments, an ID of a resource set in the list may be associated with an ID of a cell to which the activation / de-activation indication is applied. In some embodiments, an ID of a resource set in the list may be associated with one or more groups of IDs of resources in the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with one or more IDs of one or more antenna ports.

[0127] In some embodiments, the group of IDs of resources may be mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group may be mapped to an ID of a TCI state in the group of IDs of the TCI states.

[0128] In some embodiments, multiple groups of IDs of resources in the at least one resource group may be mapped to IDs of antenna ports in an ascending order. In some embodiments, the apparatus may further comprise means for transmitting, to the network device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

[0129] In some embodiments, the capability information may comprise at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for the TRS that are simultaneously activated.

[0130] In some embodiments, the apparatus may further comprise means for determining, based on at least one ID of the at least one antenna port, at least one antenna port pair between resources with a same ID of an antenna port in a resource group.

[0131] In some embodiments, the apparatus may further comprise means for determining at least one antenna port channel estimate based on the at least one antenna port pair. In some embodiments, the apparatus may further comprise means for determining an estimate of a phase difference between the antenna port channel estimates within an antenna port pair.

[0132] In some embodiments, the apparatus may further comprise means for determining an aggregated estimate of a phase difference based on at least one estimate of phase difference of the at least one antenna port pair.

[0133] In some embodiments, the apparatus may further comprise means for determining a frequency offset per resource group to be applied for a physical downlink shared channel (PDSCH) demodulation reference signal (DMRS) and a PDSCH as well as for a physical uplink shared channel (PUSCH) DMRS and a PUSCH.

[0134] In some embodiments, the activation / de-activation indication may be received via a medium access control control element (MAC CE). In some embodiments, the ID of the cell may comprise one of a serving cell physical ID or a non-serving cell physical ID. In some embodiments, the at least one resource set may comprise at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource. In some embodiments, the at least one resource set may be for the TRS and downlink (DL) CSI acquisition. In some embodiments, the at least one resource group may be for the TRS.

[0135] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0136] In some embodiments, an apparatus capable of performing any of the method 700 (for example, the network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0137] In some embodiments, the apparatus comprises means for transmitting, to a terminal device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource.

[0138] In some embodiments, the at least one resource group may be associated with at least one resource set. In some embodiments, the activation / de-activation indication may comprise at least one of the following: a list of at least one identity (ID) of the at least one resource set associated with serving or nonserving cell to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated; a list of at least one ID of at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the atleast one resource group to be de-activated.

[0139] In some embodiments, an ID of a resource set in the list may be associated with an ID of a cell to which the activation / de-activation indication is applied. In some embodiments, an ID of a resource set in the list may be associated with one or more groups of IDs of resources in the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group. In some embodiments, a group of IDs of resources in the at least one resource group may be associated with one or more IDs of one or more antenna ports.

[0140] In some embodiments, the group of IDs of resources may be mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group may be mapped to an ID of a TCI state in the group of IDs of the TCI states.

[0141] In some embodiments, multiple groups of IDs of resources in the at least one resource group may be mapped to IDs of antenna ports in an ascending order. In some embodiments, the apparatus may further comprise means for receiving, from the terminal device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

[0142] In some embodiments, the capability information may comprise at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for the TRS that are simultaneously activated.

[0143] In some embodiments, the activation / de-activation indication may be received via a medium access control control element (MAC CE). In some embodiments, the ID of the cell may comprise one of a serving cell physical ID or a non-serving cell physical ID. In some embodiments, the at least one resource set may comprise at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource. In some embodiments, the at least one resource set may be for the TRS and downlink (DL) CSI acquisition. In some embodiments, the at least one resource group may be for the TRS.

[0144] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0145] FIG. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 may be provided to implement the communication device, for example the terminal device 110 or the network device 120 as shown in Fig. 1A. As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

[0146] The communication modules 840 are for bidirectional communications. The communication modules 840 has at least one antenna to facilitate communication. The communication interface mayrepresent any interface that is necessary for communication with other network elements.

[0147] The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0148] The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a read only memory (ROM) 824, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.

[0149] A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

[0150] The embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of example embodiments of the disclosure as discussed with reference to Figs. 2 to 9. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0151] In some embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig.9 shows an example of the computer readable medium 900 in form of CD or DVD. The computer readable medium has the program 830 stored thereon.

[0152] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0153] Example embodiments of the present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the methods 600 and 700 as described above with reference to Figs. 6-7. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0154] Program code for carrying out methods of example embodiments of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0155] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0156] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non- transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0157] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details arecontained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0158] Although example embodiments of the present disclosure have been described in languages specific to structural features and / or methodological acts, it is to be understood that the example embodiments of the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:1 . A terminal device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a network device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource; and activate or de-activate, based on the activation / de-activation indication, the at least one resource group with one or more resources with the at least one antenna port.

2. The terminal device of claim 1 , wherein the at least one resource group is associated with at least one resource set.

3. The terminal device of claim 1 or 2, wherein the activation / de-activation indication comprises at least one of the following: a list of at least one identity (ID) of the at least one resource set associated with serving or nonserving cell to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated; a list of at least one ID of the at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the at least one resource group to be de-activated.

4. The terminal device of claim 3, wherein at least one of the following: an ID of a resource set in the list is associated with an ID of a cell to which the activation / de-activation indication is applied; an ID of a resource set in the list is associated with one or more groups of IDs of resources in the at least one resource group; a group of IDs of resources in the at least one resource group is associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group; or a group of IDs of resources in the at least one resource group are associated with one or more IDsof one or more antenna ports.

5. The terminal device of claim 4, wherein one of the following: the group of IDs of resources are mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group is mapped to an ID of a TCI state in the group of IDs of the TCI states.

6. The terminal device of claim 4, wherein multiple groups of IDs of resources in the at least one resource group are mapped to IDs of antenna ports in an ascending order.

7. The terminal device of any of claims 1 -6, wherein the terminal device is further caused to: transmit, to the network device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

8. The terminal device of claim 7, wherein the capability information comprises at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for the TRS that are simultaneously activated.

9. The terminal device of any of claims 1 -8, wherein the terminal device is further caused to: determine, based on at least one ID of the at least one antenna port, at least one antenna port pair between resources with a same ID of an antenna port in a resource group.

10. The terminal device of claim 9, wherein the terminal device is further caused to: determine at least one antenna port channel estimate based on the at least one antenna port pair.11 . The terminal device of any of claims 1-10, wherein the terminal device is further caused to: determine an estimate of a phase difference between the antenna port channel estimates within an antenna port pair.

12. The terminal device of claim 11 , wherein the terminal device is further caused to: determine an aggregated estimate of a phase difference based on at least one estimate of phasedifference of the at least one antenna port pair.

13. The terminal device of any of claims 1-12, wherein the terminal device is further caused to: determine a frequency offset per resource group to be applied for a physical downlink shared channel(PDSCH) demodulation reference signal (DMRS) and a PDSCH as well as for a physical uplink shared channel (PUSCH) DMRS and a PUSCH.

14. The terminal device of any of claims 1-13, wherein at least one of the following: the activation / de-activation indication is received via a medium access control control element (MAC CE); the ID of the cell comprises one of a serving cell physical ID or a non-serving cell physical ID; the at least one resource set comprises at least one non-zero-power (NZP) channel state information (CSI) reference signal (CSI-RS) resource; the at least one resource set is for the TRS and downlink (DL) CSI acquisition; or the at least one resource group is for the TRS.

15. A network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit, to a terminal device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource.

16. The network device of claim 15, wherein the at least one resource group is associated with at least one resource set.

17. The network device of claim 15 or 16, wherein the activation / de-activation indication comprises at least one of the following: a list of at least one identity (ID) of the at least one resource set associated with serving or nonserving cell to be activated; a list of at least one ID of at least one resource to be activated; a list of at least one ID of at least one antenna port associated with the at least one resource group to be activated; a list of at least one ID of the at least one resource set to be de-activated;a list of at least one ID of at least one resource to be de-activated; or a list of at least one ID of at least one antenna port associated with the at least one resource group to be de-activated.

18. The network device of claim 17, wherein at least one of the following: an ID of a resource set in the list is associated with an ID of a cell to which the activation / de-activation indication is applied; an ID of a resource set in the list is associated with one or more groups of IDs of resources in the at least one resource group; a group of IDs of resources in the at least one resource group is associated with a group of IDs of transmission configuration indicator (TCI) states used as a quasi-co-location (QCL) source for the at least one resource group; or a group of IDs of resources in the at least one resource group are associated with one or more IDs of one or more antenna ports.

19. The network device of claim 17, wherein one of the following: the group of IDs of resources are mapped to an ID of a TCI state in the group of IDs of the TCI states; or an ID of a resource in the group is mapped to an ID of a TCI state in the group of IDs of the TCI states.

20. The network device of claim 17, wherein multiple groups of IDs of resources in the at least one resource group are mapped to IDs of antenna ports in an ascending order.21 . The network device of any of claims 15-20, wherein the network device is further caused to: receive, from the terminal device, capability information for a dynamic indication of at least one resource for the TRS associated with at least one resource set.

22. The network device of claim 21 , wherein the capability information comprises at least one of the following: a maximum number of the at least one resource set for the TRS that are simultaneously activated; or a maximum number of one or more resources per resource set for TRS that are simultaneously activated.

23. The network device of any of claims 15-22, wherein at least one of the following: the activation / de-activation indication is transmitted via a medium access control control element (MAC CE); the ID of the cell comprises one of a serving cell physical ID or a non-serving cell physical ID; the at least one resource set comprises at least one non-zero-power (NZP) channel state information(CSI) reference signal (CSI-RS) resource; the at least one resource set is for the TRS and downlink (DL) CSI acquisition; or the at least one resource group is for the TRS.

24. A method comprising: receiving, at a terminal device from a network device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource; and activating or de-activating, based on the activation / de-activation indication, the at least one resource group with one or more resources with the at least one antenna port.

25. A method comprising: transmitting, at a network device to a terminal device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource.

26. An apparatus comprising: means for receiving, at a terminal device from a network device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource; and means for activating or de-activating, based on the activation / de-activation indication, the at least one resource group with one or more resources with the at least one antenna port.

27. An apparatus comprising: means for transmitting, at a network device to a terminal device, an activation / de-activation indication for at least one resource group with one or more resources with at least one antenna port for a tracking reference signal (TRS) resource.

28. A computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of claim 24 or 25.

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