Reference signal transmission

Abstract

A method is provided, comprising: determining a presence indicator configuration that defines how to interpret a presence indicator, wherein, based on the configuration, the presence indicator indicates whether a set of one or more configured reference signal opportunities of a cell carries a reference signal; obtaining the presence indicator from a base station; obtaining at least one reference signal configuration from the base station, each reference signal configuration indicating at least one configured reference signal opportunity; and determining, based on the presence indicator and the obtained presence indicator configuration, whether a given reference signal opportunity indicated by the at least one reference signal configuration carries a reference signal.

Description

Technical Field

[0001] Various example embodiments generally relate to transmission of reference signals for idle / inactive users in a communication network. Background Art

[0002] For user equipment (UE) power, it may be unwise for idle / inactive UEs to attempt to blindly decode every reference signal opportunity in a cell. In particular, for reference signals that are always on, such as tracking reference signals / channel state information reference signals (TRS / CSI-RS), transmission by the gNB is unnecessary. For example, when there are no connected UEs in the cell, the gNB may decide to refrain from TRS / CSI-RS transmission. Therefore, a method is needed to indicate the TRS / CSI-RS opportunity(s) available to connected mode UEs to idle / inactive mode UEs while minimizing the impact on system overhead. Summary of the Invention

[0003] According to some aspects, the subject matter of the independent claims is provided. Further aspects are defined in the dependent claims.

[0004] Embodiments that do not fall within the scope of the claims are to be construed as examples useful for understanding the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Hereinafter, the present invention will be described in more detail with reference to embodiments and accompanying drawings, in which

[0006] Figure 1 A communication network according to one embodiment is presented;

[0007] Figures 2 to 5 、 Figure 7 and Figure 8 illustrates a flow chart according to some embodiments;

[0008] Figure 6A and 6B depicts an example PI configuration according to some embodiments; and

[0009] Figure 9 and 10 An apparatus according to some embodiments is illustrated. DETAILED DESCRIPTION

[0010] The following examples are exemplary. Although the description may refer to "an," "one," or "some" embodiment(s) in several locations throughout the text, this does not necessarily mean that each reference refers to the same embodiment(s), or that particular features only apply to a single embodiment. The individual features of the different embodiments may also be combined to provide for other embodiments. For purposes of this disclosure, phrases "A or B" and "A and / or B" mean (A), (B), or (A and B). For purposes of this disclosure, phrases "A, B, and / or C" mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0011] The described embodiments may be implemented in a radio system, such as a radio system including at least one of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile Communications (GSM, 2G), GSMEDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System (UMTS, 3G) based on basic Wideband Code Division Multiple Access (W-CDMA), High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), LTE Advanced, and Enhanced LTE (eLTE). The term 'eLTE' herein refers to the evolution of LTE connected to a 5G core. LTE is also known as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN). The term "resource" may refer to a radio resource, such as a physical resource block (PRB), a radio frame, a subframe, a time slot, a subband, a frequency region, a subcarrier, a beam, etc. The terms "transmit" and / or "receive" may refer to sending and / or receiving wirelessly on a radio resource via a wireless propagation channel.

[0012] However, the embodiments are not limited to the systems / RATs given as examples, and those skilled in the art may apply the solutions to other communication systems that provide the necessary features. One example of a suitable communication system is a 5G system. The 3GPP solution for 5G is called New Radio (NR). 5G is envisioned to use multiple-input multiple-output (MIMO) multi-antenna transmission technology, more base stations or nodes than current LTE network deployments (the so-called small cell concept), including macro sites operating in collaboration with smaller local access nodes, and may also adopt a variety of radio technologies to achieve better coverage and enhanced data rates. 5G will likely consist of more than one radio access technology / radio access network (RAT / RAN), each optimized for certain use cases and / or spectrum. 5G mobile communications can have a wider range of use cases and related applications (including video streaming, augmented reality), different data sharing methods, and various forms of machine-type applications (including vehicle safety, different sensors, and real-time control). 5G is expected to have multiple radio interfaces, namely sub-6 GHz, cmWave, and mmWave, and integrate with existing traditional radio access technologies (such as LTE).

[0013] The current architecture in LTE networks is distributed across the radio and centralized in the core network. Low-latency applications and services in 5G require content to be brought close to the radio, leading to local outages and multi-access edge computing (MEC). 5G enables analysis and knowledge generation to occur at the data source. This approach requires leveraging resources that may not be continuously connected to the network, such as laptops, smartphones, tablets, and sensors. MEC provides a distributed computing environment for hosting applications and services. It also has the ability to store and process content close to cellular users to speed up response times. Edge computing encompasses a variety of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed point-to-point self-organizing networking and processing (also categorized as local cloud / fog computing and grid / mesh computing), dewpoint computing, mobile edge computing, cloud, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, the Internet of Things (massive connectivity and / or latency-critical), and critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, and healthcare applications). The edge cloud can be brought into the RAN by leveraging network function virtualization (NVF) and software-defined networking (SDN). Using an edge cloud can mean performing access node operations at least partially in a server, host, or node that is operatively coupled to a remote radio head or base station, including the radio portion. Network slicing allows for the creation of multiple virtual networks on top of a common shared physical infrastructure. The virtual networks can then be customized to meet the specific needs of an application, service, device, customer, or operator.

[0014] In radio communications, node operations may be performed at least partially in a central / centralized unit (CU) (e.g., a server, host, or node), which is operatively coupled to distributed units (DUs) (e.g., radio heads / nodes). Node operations may also be distributed across multiple servers, nodes, or hosts. It should also be understood that the division of labor between core network operations and base station operations may vary depending on the implementation. Therefore, the 5G network architecture may be based on so-called CU-DU splitting. One gNB-CU controls several gNB-DUs. The term 'gNB' in 5G may correspond to an eNB in ​​LTE. A gNB(s) may communicate with one or more UEs. A gNB-CU (central node) may control multiple spatially separated gNB-DUs, acting at least as transmit / receive (Tx / Rx) nodes. However, in some embodiments, the gNB-DU (also referred to as DU) may include, for example, the radio link control (RLC), medium access control (MAC) layer, and physical (PHY) layer, while the gNB-CU (also referred to as CU) may include layers above the RLC layer, such as the packet data convergence protocol (PDCP), radio resource control (RRC), and internet protocol (IP). Other functional splits are also possible. It should be assumed that those skilled in the art are familiar with the OSI model and the functions within each layer.

[0015] In one embodiment, a server or CU can generate a virtual network through which the server communicates with the radio nodes. In general, virtual networking can involve the process of combining hardware and software network resources and network functions into a single, software-based management entity (virtual network). This virtual network can provide a flexible distribution of operations between servers and radio heads / nodes. In practice, any digital signal processing task can be performed in either the CU or the DU, and the boundaries for transferring responsibilities between the CU and the DU can be selected based on the implementation.

[0016] Some other technological advancements that may be leveraged are software-defined networking (SDN), big data, and all-IP, to name a few non-limiting examples. For example, network slicing can take the form of a virtual network architecture that uses the same principles as software-defined networking (SDN) and network function virtualization (NFV) in fixed networks. SDN and NFV can deliver greater network flexibility by allowing traditional network architectures to be divided into virtual components that can be linked (also via software). Network slicing allows the creation of multiple virtual networks on top of a common shared physical infrastructure. The virtual networks can then be customized to meet the specific needs of applications, services, devices, customers, or operators.

[0017] Multiple gNBs (access points / nodes) can connect to each other via the Xn interface, with each gNB comprising a CU and one or more DUs, over which the gNBs can negotiate. The gNBs can also connect to the 5G Core Network (5GC) via a Next Generation (NG) interface, which can be the 5G equivalent of the LTE Core Network. This 5G CU-DU split architecture can be implemented using the cloud / server, with the CU, which has higher layers, located in the cloud, and the DU, which is closer to or includes the actual radio and antenna units. Similar initiatives are underway for LTE / LTE-A / eLTE. While both eLTE and 5G will use similar architectures within the same cloud hardware (HW), the next step may be to combine the software (SW) so that a common SW controls both radio access networks / technologies (RAN / RAT). This could enable new ways to control radio resources for both RANs. Furthermore, configurations are possible where the entire protocol stack is controlled by the same HW as the CU and processed by the same radio units as the CU.

[0018] It should also be understood that the labor distribution between core network operations and base station operations may be different from that of LTE, or even non-existent. Some other technological advancements that may be used are big data and all-IP, which can change the way networks are constructed and managed. 5G (or New Radio, NR) networks are designed to support multiple hierarchical structures, in which MEC servers can be placed between the core and base stations or nodeBs (gNBs). It should be understood that MEC can also be applied to 4G networks.

[0019] 5G can also leverage satellite communications to enhance or supplement the coverage of 5G services, for example by providing backhaul. Possible use cases include providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers in vehicles, or ensuring service availability for critical communications and future rail / maritime / aeronautical communications. Satellite communications can leverage geosynchronous orbit (GEO) satellite systems, but can also leverage low-Earth orbit (LEO) satellite systems, particularly mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite in a mega-constellation can cover several satellite-enabled network entities, creating terrestrial cells. Terrestrial cells can be created via terrestrial relay nodes or via gNBs located on the ground or in satellites.

[0020] These embodiments may also be applied to narrowband (NB) Internet of Things (IoT) systems, which can use cellular telecommunication bands to enable connectivity for various devices and services. NB-IoT is a narrowband radio technology designed for the Internet of Things and is one of the technologies standardized by the Third Generation Partnership Project (3GPP). Other 3GPP technologies are also suitable for implementing embodiments, including machine type communications (MTC) and eMTC (enhanced machine type communications). NB-IoT is particularly focused on low cost, long battery life, and enabling a large number of connected devices. NB-IoT technology is deployed "in-band" in the spectrum allocated to Long Term Evolution (LTE) - using resource blocks within a normal LTE carrier, or unused resource blocks within a guard band of an LTE carrier - or "standalone" for deployment in dedicated spectrum.

[0021] Embodiments may also be applied to device-to-device (D2D), machine-to-machine, point-to-point (P2P) communications, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), infrastructure-to-vehicle (I2V), or generally to V2X or X2V communications.

[0022] Figure 1 The diagram illustrates an example of a communication system to which embodiments of the present invention may be applied. The system may include a control node 110 and a control node 112, wherein the control node 110 provides one or more cells (such as cell 100) and the control node 112 provides one or more other cells (such as cell 102). For example, each cell may be, for example, a macrocell, a microcell, a femtocell, or a picocell. From another perspective, a cell may define a coverage area or service area of ​​a corresponding access node. The control nodes 110 and 112 may be evolved NodeBs (eNBs) such as in LTE and LTE-A, ng-eNBs such as in eLTE, gNBs for 5G, or any other device capable of controlling radio communications and managing radio resources within a cell. The control nodes 110 and 112 may be referred to as base stations, network nodes, or access nodes.

[0023] The system may be a cellular communication system consisting of a radio access network of access nodes, each of which controls one or more cells. Access nodes 110 may provide user equipment (UE) 120 (one or more UEs) with wireless access to other networks, such as the Internet. Wireless access may include downlink (DL) communications from a control node to UE 120 and uplink (UL) communications from UE 120 to the control node.

[0024] In addition, although not shown, one or more local area access nodes may be arranged so that the cells provided by the local area access nodes at least partially overlap with the cells of access nodes 110 and / or 112. A local area access node may provide wireless access within a subcell. Examples of a subcell may include a microcell, a picocell, and / or a femtocell. Typically, a subcell provides a hotspot within a macrocell. The operation of a local area access node may be controlled by an access node, under which the subcell is provided. Generally speaking, the control node of a small cell may also be referred to as a base station, a network node, or an access node.

[0025] There may be multiple UEs 120, 122 in the system. Each of them may be served by the same or different control nodes 110, 112. In case a D2D communication interface is established between the UEs 120, 122, the UEs 120, 122 may communicate with each other.

[0026] The term "terminal device" or "UE" refers to any terminal device capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated process chain environments), consumer electronic devices, devices 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.

[0027] In the case of multiple access nodes in a communication network, the access nodes can be connected to each other through an interface. The LTE specification refers to this interface as the X2 interface. For IEEE802.11 networks (i.e., wireless local area networks, WLAN, WiFi), a similar interface Xw can be provided between access points. The interface between an eLTE access point and a 5G access point or between two 5G access points can be referred to as Xn. Other communication methods between access nodes are also possible. Access nodes 110 and 112 can also be connected to the core network 116 of the cellular communication system via another interface. The LTE specification specifies the core network as an evolved packet core (EPC), and the core network may include a mobility management entity (MME) and a gateway node. The MME can handle the mobility of terminal devices in a tracking area covering multiple cells, and handle the signaling connection between the terminal device and the core network. The gateway node can handle data routing in the core network and data routing to / from the terminal device. The 5G specification specifies the core network as the 5G Core (5GC), and the core network may include, for example, the Access and Mobility Management Function (AMF) and the User Plane Function / Gateway (UPF), to name a few. The AMF may handle termination of non-access stratum (NAS) signaling, NAS encryption and integrity protection, registration management, connection management, mobility management, access authentication and authorization, and security context management. The UPF node may support, for example, packet routing and forwarding, packet inspection, and QoS processing.

[0028] Reference signals are used to communicate a reference point from a transmitter to a receiver. The contents of the reference signal are known to both parties, so the reference signal can be used, for example, to extract propagation channel characteristics. For example, the CSI-RS, which can be received by a UE, can be used to estimate the channel and report channel quality information back to the gNB. The term CSI-RS refers to channel state information reference signal, and these signals are typically transmitted in the downlink. They can also be used for reference signal received power (RSRP) measurements during mobility and beam management, as well as for frequency / time tracking, demodulation, and UL reciprocity-based precoding. CSI-RS can be configured specifically for a UE, but in some implementations, multiple users can share the same reference signal resource. CSI-RS can be periodic, semi-persistent, or aperiodic (due to downlink control information, DCI, triggers). For time / frequency tracking, CSI-RS can be periodic or aperiodic. Although this description uses CSI-RS as an example, the described embodiments are applicable to any other reference signal type.

[0029] A TRS / CSI-RS opportunity is a time / frequency resource configuration used to transmit CSI-RS from a gNB in ​​a cell. A TRS / CSI-RS may include the transmission of CSI-RS in one or more symbols in one or more time slots. A time slot may include one or more symbols. TRS / CSI-RS opportunity(s) available for connected mode UEs may be shared with idle / inactive mode UEs. However, it should be noted that the TRS / CSI-RS in a TRS / CSI-RS opportunity may or may not actually be transmitted. Whether TRS / CSI-RS is transmitted for idle / inactive UEs depends on the gNB implementation, even when connected UEs do not require TRS / CSI-RS (e.g., when a connected mode UE is present in the cell but the UE no longer uses TRS / CSI-RS, or when there are no longer any connected mode UEs in the cell).

[0030] In one embodiment, system information block (SIB) signaling provides idle / inactive UE(s) with the configuration of TRS / CSI-RS occasion(s). In other words, this indicates to the idle / inactive UEs when CSI-RS can potentially be transmitted. As described above, the gNB may not transmit CSI-RS at every available opportunity. Therefore, it may be beneficial for the UE not to blindly decode every opportunity. However, one option is to not inform the UE of the availability of TRS / CSI-RS for the configured occasion(s). This may require the UE to blindly decode every opportunity. In some other options, the UE is informed of the availability of TRS / CSI-RS for the configured occasion(s). This allows the UE to know which occasions actually carry CSI-RS. However, in one option, the UE is informed of the conditional availability of TRS / CSI-RS for the configured occasion(s), where the condition may be, for example, the presence of paging. Any combination of these options is also applicable.

[0031] In NR, multiple beams can exist in a cell. For example, a synchronization signal block (SSB) can carry one or more CSI-RSs, as well as other information. The SSB refers to a synchronization / PBCH block because the synchronization signal and the PBCH channel are packaged into a single block. Components of this block can include synchronization signals: PSS (Primary Synchronization Signal) and SSS (Secondary Synchronization Signal), as well as the Physical Broadcast Channel (PBCH), which carries the PBCH Demodulation Reference Signal (DMRS) and PBCH data.

[0032] For example, in NR Release 15, the UE is informed of the SSBs actually transmitted in the serving cell via broadcast and / or (optionally) dedicated signaling. In FR1, which supports up to 8 SSBs, a single 8-bit field (inOneGroup) is used to convey this information in the broadcast. In FR2, up to 64 SSBs are supported. The indication of the SSB actually transmitted in the 64 candidate SSB positions in FR2 is provided via two 16-bit fields (groupPresence and inOneGroup) in ssb-PositionsInBurst. Information about the 64 candidate SSB positions is compressed by dividing the 64 candidate positions into 8 groups, with 8 candidate positions in each group. The IE "inOneGroup" indicates in 8 bits which of the eight candidate positions in each active group are actually transmitted SSBs. Then, for the UE's 'groupPresence', an 8-bit field is used to indicate which of the eight possible groups are active, i.e., have transmitted SSBs as indicated by the 'inOneGroup' field. Therefore, each active group in the active group can have the same number of transmitted SSBs. Although described in an 8+8 configuration, any number of beams in any type of group configuration is possible.

[0033] The TRS configuration is provided via NZP-CSI-RS-ResourceSet, where each individual RS configuration belonging to the resource set is indicated via an ID, and the trs-Info flag is used to indicate whether the RS configuration shares the same antenna port. Each resource ID may correspond to an RS configuration provided by NZP-CSI-RS-Resource, where NZP stands for non-zero power. In a TRS configuration, there are two RS symbols per slot (in one or two slots), so there are two RS configurations (NZP-CSI-RS-Resource) in the corresponding resource set (NZP-CSI-RS-ResourceSet) of each slot. The NZP-CSI-RS-Resource IE includes, for example, the following IEs:

[0034] - 'NZP-CSI-RS-ResourceId' gives the logical index of the RS configuration,

[0035] -'CSI-RS-ResourceMapping' and 'CSI-ResourcePeriodicityAndOffset' provide frequency and time domain mapping of RS to physical resources,

[0036] 'CSI-RS-ResourceMapping' contains the resource element positions in the frequency domain, the number of antenna ports and the symbol positions (in the time slot). In addition, information on code domain multiplexing (CDM) and density is also provided in this IE.

[0037] In the case of TRS, some parameters in 'CSI-RS-ResourceMapping' have fixed values ​​or value ranges. That is, the number of antenna ports is set to 1 ('nrofPorts'), CDM is not allowed ('cdm-type'), and density ('density') is fixed to 3. Therefore, when providing information about TRS opportunities for idle / inactive mode UEs, these parameters can, in principle, be omitted from the parameters.

[0038] - 'powerControlOffsetSS' sets the power offset that the UE can assume relative to the SSS,

[0039] Note: 'powerControlOffsetSS' may not be necessary for idle / inactive UEs

[0040] - 'ScramblingId' determines the scrambling initialization, and

[0041] - 'qcl-InfoPeriodicCSI-RS' provides a reference to the TCI status of the QCL resource indicating the (T)RS.

[0042] The QCL relationship information between two reference signals can provide the UE with information (which can be configured by the network) about the sharing of specific characteristics between the reference signals. The characteristics can include, for example, quasi-co-location of antenna ports. QCL information or QCL relationship can refer to, but is not limited to, the following: the UE can be configured to have, for example, a list of up to M TCI state configurations within the parameter PDSCH-Config. The TCI state configuration can be used to decode the physical downlink shared channel (PDSCH) based on the detected PDCCH, which has downlink control information (DCI) intended for the UE and a given serving cell. M may depend on the UE capability maxNumberConfiguredTCIstatesPerCC. Each TCI state may include parameters for configuring a quasi-co-location relationship between one or two downlink reference signals and the DMRS port of the PDSCH, the DMRS port of the PDCCH, or (multiple) CSI-RS ports of the CSI-RS resource. The quasi-co-location relationship can be configured by the parameter qcl-Type1 for the first DL RS and the parameter qc1-Type2 for the second DL RS. For the case of two DL RSs, the QCL type may be different, regardless of whether the reference is to the same DL RS or to different DL RSs. The quasi-co-location type corresponding to each DL RS may be provided by the parameter qcl-Type in the QCL-Info information element (IE) and may take one of the following values: 1) 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}; 2) 'QCL-TypeB': {Doppler shift, Doppler spread}; 3) 'QCL-TypeC': {Doppler shift, average delay}; 4) 'QCL-TypeD': {spatial Rx parameters}.

[0043] One aspect that should be considered for TRS / CSI-RS opportunities (multiple) for idle / inactive mode UEs is the indication of the presence of potential TRS / CSI-RS at the provided opportunity ('Presence Indication', PI), as opposed to the UE autonomously detecting the presence of TRS / CSI-RS opportunities. From a network power consumption perspective, it is undesirable to grant unnecessary transmissions of transmissions such as TRS if there are no connected mode UEs using them. This can lead to unnecessary overhead if presence indications are sent frequently, or if connected mode UEs are only present in a subset of the cell area / beam.

[0044] As an example, the UE may be provided with TRS / CSI-RS opportunities, i.e., configurations in the system information, but whether the network actually sends TRS / CSI-RS on the provided opportunities may change quite dynamically. In the absence of a presence indication and only a configuration, the UE would need to perform blind detection of the signal. This could potentially diminish the benefits of power saving. If the UE cannot be sure that the RS is actually present in the notified / configured opportunities, the UE will not be able to make maximum use of them. For example, the UE will not be able to skip SSB monitoring opportunities in advance and believe that it can receive potential (multiple) TRS / CSI-RS opportunities later, which may be beneficial for, for example, updating time / frequency synchronization (e.g. for paging monitoring). From this perspective, the presence indication would be beneficial. Furthermore, in a beam-based system, connected mode UEs may only be present in a subset of beams, and beams may be UE-specific, so active TRS / CSI-RS may not be present on all beams.

[0045] As shown above, one issue with TRS / CSI-RS is that the UE may not know whether the gNB transmits TRS / CSI-RS in the configured RS occasions. To at least partially address this issue, a solution is proposed for indicating the presence of TRS / CSI-RS at one or more configured RS occasions in an efficient manner.

[0046] Figure 2 An example method is depicted. The method may be performed by a user equipment (such as UE 120). In one embodiment, UE 120 is a user equipment (residing) in a radio resource control (RRC) idle or inactive state. In this RC idle or RRC inactive mode, the UE may detect paging and broadcasting performed by a network node (such as BS 110). In addition, UE 120 may attempt to decode RS on (multiple) RS opportunities.

[0047] Therefore, if Figure 2 As shown, UE 120 may determine the presence indicator (PI) configuration, i.e., the PI configuration, in step 200. In one embodiment, the UE determines the PI configuration based on a pre-configuration of the UE. In another embodiment, the UE determines the PI configuration based on information indicating the PI configuration received from a base station of a cell (e.g., from gNB 110). For example, the PI configuration may be received in a control message.

[0048] In one embodiment, based on the configuration, the presence indicator indicates whether one or more configured reference signal opportunity sets of the cell carry a reference signal.

[0049] In one embodiment, based on the configuration, the presence indicator indicates whether a set of one or more configured reference signal opportunities associated with at least one synchronization signal block (SSB) of the cell carries a reference signal.

[0050] In one embodiment, a first configuration may be indicated, as depicted in step 200A. In this configuration, the set may include all configured RS opportunities in the cell. According to the first configuration, the PI indicates whether all or no reference signal opportunities associated with the SSB of the cell carry a reference signal. In this embodiment, the PI may be, for example, a one-bit indicator, where a bit '1' indicates that the network node uses all RS opportunities to transmit RS, and a bit '0' indicates that no RS opportunity is used by the network node to transmit RS in the cell, and vice versa.

[0051] In one embodiment, a second configuration may be indicated, as depicted in step 200B. In this configuration, the set may include only a subset of the configured RS opportunities in the cell. That is, the subset includes at least one, but not all, configured reference signal opportunities for the cell. According to the second configuration, the PI (or a bit in the PI) indicates whether the subset of reference signal opportunities associated with at least one SSB of the cell carries a reference signal.

[0052] In this embodiment, the length of the PI may be one or several bits (or multiple 1-bit PIs may be configured). If only the second configuration is indicated, the second configuration is the only configuration, even though the term "second" is used herein.

[0053] In one embodiment, a subset or each subset (in the case of several bits in the PI) may include RS opportunities in one or more SSBs or one or more SSB groups. In one embodiment, a subset may include RS opportunities based on one or more RS configurations or based on one or more RS configuration groups.

[0054] In the second configuration, the PI or each bit of the PI may refer to a specific one or more RS configurations or to one or more SSBs, but not to all RS configurations or SSBs of the cell. Each RS configuration or SSB may be associated with one or more RS opportunities, so that a subset of at least one RS opportunity is indicated to the UE by the PI or each bit of the PI. For example, the PI sent to the UE may refer to SSB#1 (= opportunity in SSB#1 or in SSB group #1) or RSconfig#1 (= opportunity based on RSconfig#1 or based on RSconfig group #1). For example, when there are many bits, the first bit of the PI may refer to SSB#1, and another bit refers to another SSB ID. It should be noted that because each RS configuration is associated with a specific one or more SSBs, the indicated subset directly or at least implicitly refers to one or more SSBs.

[0055] In one embodiment, there may be multiple configurations provided to the UE to allow the gNB to later dynamically change the configuration between the multiple provided PI configurations. In one embodiment, both the first and second configurations are initially provided to the UE, and an indication of which configuration to use may be provided to the UE later. For example, in one embodiment, the PI configuration (e.g., sent via RRC) may include a flag / configuration to indicate whether the PI (perhaps 1 bit) corresponds to all configured opportunities in the cell, or whether the UE is to follow a subset-specific PI configuration.

[0056] In step 202, UE 120 may receive a presence indicator (PI) from a base station. It should be noted that the order of the steps may be different from Figure 2 Rather, the PI may be received, for example, before or simultaneously with the PI configuration of step 200. As described above, the PI may have one or more bits depending on the embodiment.

[0057] In one embodiment, the UE may receive a configuration for SSB transmission during an SS burst in cell 102. This may be received via, for example, System Information Block 1 (SIB1).

[0058] In step 204, the UE may obtain at least one reference signal configuration from the base station, each reference signal configuration indicating at least one configured reference signal opportunity. Again, the order of steps 200-204 may be different from Figure 2 The sequence depicted. The RS configuration (also called RS resource configuration) can be carried to the UE in a dedicated manner in the SIB, or in the RRC connection release or other RRC signaling. In one embodiment, the configuration of RS opportunities for idle / inactive mode UEs can be provided independently for each broadcast / SSB beam.

[0059] For example, the reference signal opportunities indicated by a given RS configuration may be included in one or more SSBs. For example, the RS configuration may specify RS opportunities by time and frequency location, and / or by association with quasi-co-location of one or more SSBs (e.g., via TCI-stateId in the RS configuration). In other words, each RS configuration may have parameters that associate the RS configuration with a specific one or more SSBs. In yet another embodiment, the UE 120 may alternatively or additionally receive a configuration message that provides the UE 120 with information about an association between one or more TRS / CSI-RS (i.e., the opportunities indicated in one or more RS configurations) and one or more SSBs.

[0060] In one embodiment, RS configuration is provided for all SSBs in the cell.The presence indication then further indicates whether TRS is actually present in the configured RS opportunity of the SSB.

[0061] In step 206, the UE may determine whether a given reference signal opportunity indicated by at least one RS configuration carries a reference signal based on the PI and the obtained PI configuration. Based on this determination, the UE may advantageously decide whether to monitor the reference signal in a given RS opportunity. If the network node does not transmit anything at a given opportunity, the UE may advantageously save power by not performing blind detection for the given RS opportunity.

[0062] In one embodiment, the RS includes a tracking reference signal and / or a channel state information reference signal (TRS / CSI-RS) transmitted in the downlink from base station 110. The RS transmission timing may be defined by the received RS configuration. However, as described above, the PI further indicates whether the timing is actually used by gNB 110 for RS transmission.

[0063] Although TRS / CSI-RS are used as example reference signals in the description, the proposed embodiments are also applicable to any other types of reference signals.

[0064] In one embodiment, the association between RS opportunities and SSBs is based on at least one of the following: a quasi-co-location relationship between the reference signal opportunities and the SSBs, a time-frequency location of the reference signal opportunities relative to (multiple) SSBs, and an association configuration message received from the network. For example, the RS opportunities are defined in the received RS configuration, and the RS configuration may have a specific quasi-co-location (QCL) with a specific one or more SSBs. Thus, these opportunities are QCLed with the (multiple) SSBs. As another example, the (multiple) time and / or frequency locations of the (multiple) opportunities may at least partially overlap with the (multiple) SSBs, and if this occurs, the opportunities (or a subset thereof) may be associated with the overlapping SSBs.

[0065] In one embodiment, according to at least the second configuration for the PI, the PI indicates at least one SSB of the cell where the reference signal exists, but not all SSBs. In the case where the SSBs are grouped, the PI may indicate at least one SSB group of the cell where the reference signal exists, but not all SSB groups.

[0066] In another embodiment, the PI indicates at least one reference signal configuration of the cell according to which the reference signal is transmitted, but not all reference signal configurations. In the case where the RS configuration is grouped, the PI may indicate at least one RS configuration group of the cell according to which the reference signal is actually transmitted, but not all RS configuration groups, that is, the reference signal exists.

[0067] In one embodiment, Figure 3 As shown, in step 300, UE 120 detects a channel on which a PI is received. Then, in step 302, the UE associates the detected channel with at least one SSB. For example, the UE may determine which SSB is received from the same spatial direction (which may be referred to as QCL type D, spatial RX, and other QCL types are not excluded) as the channel on which the PI exists. This may mean QCL between the PI and (multiple) SSBs. As an example, if the PI is carried by a DCI message sent using the PDCCH, or the PI is a DCI message sent using the PDCCH (DCI may or may not carry EPI / PEI information), the UE may determine the association between the PI and the SSB by assuming QCL between the DMRS of the PDCCH carrying the DCI and the SSB. In another example, if the PI is carried by a reference signal (e.g., a sequence that may or may not also be used as PEI / EPI), the reference may be associated with the SSB through a QCL relationship. Therefore, in step 304, the UE 120 may determine that the set of RS opportunities corresponding to the PI includes those RS opportunities included in the determined at least one SSB.

[0068] Figure 3 Step 306 of illustrates that UE 120 may determine that the PI also indicates the presence of configured RSs for at least one additional SSB. This may be based on grouping of SSB or RS configurations, as described below.

[0069] In one embodiment, Figure 4As shown, in step 400, UE 120 may associate at least one SSB with the obtained at least one RS configuration. This association may be based on at least one of the following: quasi-co-location information between the at least one RS configuration and the at least one SSB, a time / frequency position of an RS opportunity indicated in the RS configuration, and an association configuration message received from base station 110 indicating the association between the at least one RS configuration and the at least one SSB. Thereafter, in step 402, UE 120 may determine that a reference signal from the base station exists in the at least one SSB based on the PI and its configuration, and in step 404, determine a reference signal opportunity in the at least one SSB based on the associated at least one RS configuration.

[0070] In one embodiment, the PI is received in each of at least one RS configuration that the UE 120 can receive. This can provide an efficient way to associate a given PI with a specific RS configuration and / or with at least one SSB that is associated with the RS configuration (via QCL). In the case where the presence indication is carried in the RS configuration itself, a dynamic presence indication could potentially lead to a large number of SI update indications in the cell. In this case, a special SI update indication can be used to indicate that the PI has changed for the cell. UEs that are not interested in monitoring the RS can then ignore the SI update.

[0071] In one embodiment, the presence indicator is received in an early paging indicator message (EPI / PEI). For NR idle / inactive mode paging enhancement, paging early indication before the paging occasion (PO) can be supported. The paging early indication before the target PO can also be referred to as wake-up signaling (WUS) or DCP (DCI with CRC scrambled by PS-RNTI), and can be used to indicate to the UE whether the UE needs to wake up to monitor the physical downlink control channel (PDCCH) scrambled with the paging radio network temporary identifier (P-RNTI) at the PO. In other words, the EPI / PEI can indicate to the UE whether it will be paged on the PO associated with the EPI / PEI or can be paged on the PO associated with the EPI / PEI. Potential candidate indication methods include, for example, downlink control information (DCI)-based indications, such as based on extending existing DCI formats 1_0 or 2_6, or new DCI formats, or RS-based or sequence-based indications, such as based on TRS / CSI-RS or secondary synchronization signal (SSS).

[0072] In an embodiment where a PI is carried in an early paging message, the PI may be associated with a parameter that indicates at least one reference signal configuration or at least one SSB associated with the PI. In one embodiment, this association may be achieved by detecting that the spatial direction in which the PI is received (e.g., by providing the QCL relationship between the PI or the channel / RS associated with the PI and other RSs (such as SSBs)) is the same as one or more SSBs. In another embodiment, an early paging message carrying the PI is sent using a specific DCI format dedicated for this purpose, allowing UE 120 to immediately detect the presence of the PI in the early paging message.

[0073] In one embodiment, the presence indicator is received by UE 120 in a broadcast message, such as a system information broadcast message (SIB). In one embodiment, the presence indicator is received by UE 120 in a dedicated, group-specific, or broadcast manner. The PI may be sent in a MAC CE, DCI, or RRC message, or the PI is a MAC CE, DCI, or RRC message.

[0074] In one embodiment, the presence indicator is sent by the UE 120 in a system information broadcast message (SIB). In another example, the presence information may be provided in a group-specific manner in the SIB, i.e., the network may indicate that the TRS / CSI-RS exists for a specific group or multiple groups or all groups. The indication may be in the form of a bitmap. The bitmap may have a bit field for each of the SSBs and / or TRS / CSI-RSs or SSB groups and / or TRS / CSI-RS groups. The bits in the bitmap indicate whether the TRS / CSI-RS or TRS / CSI-RS group exists / is sent by the network node 110. The bitmap may include a bit field for SSBs or TRS / CSI-RSs for which no TRS / CSI-RS is configured (e.g., the bitmap may have a fixed length that may depend on the maximum number of SSBs sent by the NW 110 in the cell). In another example, the network node 110 may provide an indication of which configured TRS / CSI-RS opportunities are present in the TRS / CSI-RS (e.g., in an SIB or in other RRC messages). The indication may take the form of a bitmap, e.g., a bitmap having, for example, a bit field for each configured opportunity (an SSB-based bitmap or a TRS / CSI-RS-based bitmap), i.e., the bitmap may have entries for the configured opportunities. These opportunities may be configured in a broadcast message (such as an SIB) or in a dedicated manner via RRC.

[0075] In one embodiment, the presence indicator may be provided (and UE 120 may receive it) to UE 120 or a UE in RRC connected mode. In one embodiment, the presence indicator may be provided in an RRC message (such as an RRC release message or any message provided to UE 120 before entering idle / inactive mode). The UE may be configured (allowed) to request presence information for one or more TRS / CSI-RS opportunities. The request may be, for example, an RRC message, a MAC CE, a PUSCH message, a PUCCH message, or a RACH preamble or an uplink signal SR / SRS. The request may provide an indication to the network that the UE requests the network to provide the presence indicator.

[0076] exist Figure 5 In the illustrated embodiment, in step 500, UE 120 determines that the set carries RS based on the PI and the configuration of the PI, and that the set (subset) only includes reference signal opportunities in a given SSB. In step 502, UE 120 also determines that RS (of the same type, such as TRS / CSI-RS) is also present in at least one other SSB, which is associated with the same SSB group as the first SSB. In one embodiment, when SSBs are associated with the same grouping parameters, these SSBs belong to the same SSB group. The grouping parameters may include, for example, a groupPresence indication in the ssb-PositionsInBurst information element, which UE 120 may have received from the base station.

[0077] As with Figure 5In an example related to an embodiment of the present invention, PI is a 1-bit indication indicating that TRS / CSI-RS exists for a group of SSBs under the same grouping parameter in ssb-PositionsInBurst. When the PI-bit is set, the UE determines that all SSBs indicated to be transmitted within the same group (e.g., via the grouping parameter (groupPresence / inOneGroup)) and having configured TRS / CSI-RS opportunities can be assumed to have TRS / CSI-RS. In practice, as shown in optional step 504, a further criterion for determining that a reference signal exists in at least one other SSB may be whether the at least one other SSB is associated with an RS configuration. On the other hand, when the UE detects that the bit is not set (or is set to '0'), the UE 120 may assume that no TRS / CSI-RS opportunity exists for the entire SSB group. In one embodiment, when UE 120 detects that a PI is set for a particular TRS-CSI-RS configuration, UE 120 determines the associated SSB index (SSB used as a QCL resource for the TRS / CSI-RS) based on the TRS / CSI-RS configuration, and further determines that all SSBs indicated as being in the same group also carry reference signals. As a more specific example, let's assume that UE 120 determines that TRS / CSI-RS is configured with ID #1 (the ID of the RS configuration) and SSB #0 is configured as a QCL resource for that RS configuration, and that another TRS / CSI-RS is configured with ID #2 and SSB #1 is configured as a QCL resource, and that SSB #1 and SSB #2 are in the same group. Then, if the UE detects a PI for TRS / CSI-RS ID #1, UE 120 can determine / assume that TRS / CSI-RS ID #2 is also present based on the SSB index grouping information (i.e., sent by gNB 110). In the case where, for example, SSB#3 belongs to a different group than SSB#1 and SSB#2, UE 120 may not be sure of the presence of configured TRS / CSI-RS with SSB#3 as a QCL resource.

[0078] Similarly, in the case where the RS configurations are grouped via grouping parameters received in each RS configuration, or via a separate grouping message from the network, the UE 120 can determine that the set of RS opportunities carries a reference signal based on the presence indicator and the configuration of the presence indicator, and the set (subset) only includes RS opportunities based on or indicated by the first RS configuration. Therefore, in this embodiment, the UE 120 can also determine the presence of RS based on at least one other RS ​​configuration, the at least one other RS ​​configuration being associated with the same RS configuration group as the first RS configuration. In one embodiment, the UE receives a configuration that provides information about the association between one or more TRS / CSI-RS and one or more SSBs. The UE can also receive information about grouping one or more TRS / CSI-RS (indicated by one or more RS configurations) into one or more groups. Then, when the UE receives a PI indicating that the first SSB associated with the first RS configuration carries TRS / CSI-RS, the UE can determine / assume that at least one other SSB associated with another RS ​​configuration also carries TRS / CSI-RS to the UE, the other RS ​​configuration belonging to the same RS configuration group as the first RS configuration.

[0079] In one embodiment, the presence indicator comprises only a single bit, such as Figure 6A As shown. This may be the case, for example, in the first configuration, the PI indicates that CSI-RS exists for all or no TRS / CSI-RS opportunities in the cell, among all actually transmitted SSBs (associated with / having a TRS / CSI-RS configuration). However, the above-mentioned second PI configuration may also adopt a 1-bit configuration. For example, a 1-bit PI may indicate that a specific subset of RS opportunities is to carry RS, which is defined by the PI configuration. The PI configuration may define, for example, that the PI refers to all RS opportunities, or to RS opportunities in a specific SSB ID, or to RS opportunities based on a specific RS configuration ID.

[0080] In another embodiment, the presence indicator includes multiple bits, each bit indicating whether a given subset of configured reference signal opportunities associated with at least one SSB of the cell carries a reference signal. A PI with many bits can also be viewed as configuring multiple 1-bit PIs, each 1-bit PI indicating whether a given subset of configured RS opportunities carries a reference signal.

[0081] For example, a presence indication may be a collection of one or more groups. Figure 6BIn the depicted example, the PI may contain 8 bits, similar to the GroupPresence IE, and a bit set to '1' indicates the presence of TRS / CSI-RS in the corresponding SSB group. When a specific PI bit for an SSB group is set, the UE 120 can determine that the TRS / CSI-RS is present in all actually transmitted SSBs in the group. For the 5th block from the left, when the PI bit is set to '1' and the GroupPresence bit is set to '0', no SSB is transmitted in the 5th group, and therefore no RS is transmitted in the SSB. For an SSB group whose corresponding PI is set to '0', there is no RS transmission even if one or more SSBs of the SSB group are transmitted.

[0082] Although described above in conjunction with SSB groups, a bit-wise indication can also be performed for FR1, which may have only 8 beams. Each of the 8 bits will then indicate the presence of an RS in a given SSB, i.e., beam-specific mapping.

[0083] The definition of the subset may be communicated to the UE 120 in the presence indicator configuration of step 200. For example, the configuration may define that each bit of the PI corresponds to one SSB group of the cell (e.g., in ascending or descending order). Other types of subset definitions are also possible, such as each bit in the PI corresponds to a certain RS configuration index. In one embodiment, the definition of the subset of UEs is based on a control message. The PI configuration may be provided to the UE in a system broadcast message (e.g., in an SIB) or in a dedicated RRC message (e.g., RRC release or other RRC message). The PI configuration may be provided to the UE in RRC connected or RRC idle / inactive mode. In one example, the PI configuration or PI (presence indication information) may be provided in a system information block (in the same or different SIB).

[0084] In one embodiment, the reference signal opportunities defined by a given subset (i.e., the subset indicated by a given PI or bits of the PI) are all included in one SSB. In one embodiment, the reference signal opportunities defined by a given subset (i.e., the subset indicated by a given PI or bits of the PI) are all included in the same single SSB group.

[0085] In one embodiment, the reference signal opportunities defined by a given subset (i.e., a subset indicated by a given PI or bits of the PI) are all based on one RS configuration. In one embodiment, the reference signal opportunities defined by a given subset (i.e., a subset indicated by a given PI or bits of the PI) are all based on the same single RS configuration.

[0086] In one embodiment, the UE receives a control message indicating a mapping of the PI or bits of the PI to at least one of: SSB(s), SSB group(s), RS configuration(s), RS configuration group(s).

[0087] As previously described, in one embodiment, when multiple SSBs are associated with the same grouping parameter, these SSBs belong to the same SSB group, where the grouping parameter includes a groupPresence indication in the ssb-PositionsInBurst information element. For example, the UE may receive a control message in an SS burst that provides group information (e.g., groupPresence or inOneGroup) on the transmitted SSB. The UE may then determine the SSB grouping for TRS / CSI-RS presence based on the received SSB group information of the transmitted SSB.

[0088] In some other embodiments, the UE 120 may alternatively or additionally receive a control message indicating how the SSBs are grouped and / or how the RS (e.g., TRS / CSI-RS) configurations are grouped. The UE may then define the grouping of SSBs or the grouping of reference signal configurations based on such explicit configuration messages from the base station 110. In other words, the network may configure TRS / CSI-RS and / or configure explicit grouping for SSBs. With respect to TRS / CSI-RS groups, the presence indication works in a similar manner to the SSB grouping, i.e., when one or more RS configurations are grouped, the presence indication indicates the presence of the entire RS configuration group when one of the RS configurations in the group is detected.

[0089] In an embodiment employing a grouped configuration, the network may configure the number of groups for the TRS / CSI-RS (or SSB), and each TRS / CSI-RS configuration (or SSB) may be implicitly mapped (e.g., uniformly in a logically ascending / descending order) to a given group, or explicitly mapped (e.g., each TRS / CSI-RS configuration is mapped to a certain group or groups). Thus, for this embodiment, the grouping may be used to cause groups of SSBs or reference signal configurations to have unequal sizes. As an example, one or more TRS / CSI-RSs may be associated with one or more SSBs (e.g., by a QCL relationship), and TRS / CSI-RSs sharing the same QCL resource (e.g., SSB) may be grouped or configured to be in one group. In another example, when the PI indicates that at least one TRS / CSI-RS is present in a group, the UE 120 may assume that a TRS / CSI-RS is present for all RSs in the same group. In one example, when the PI indicates that there is at least one TRS / CSI-RS in a group, UE 120 can assume that there are TRS / CSI-RS for all RSs in the same group, where the group is determined by the QCL relationship, for example, TRS / CSI-RS with the same QCL resource RS (e.g., SSB or other CSI-RS) can be considered to be in the same group.

[0090] In one embodiment, the size of the (TRS / CSI-RS or SSB) group may be 1. In one example, if the group size is set to 1, the presence indication may indicate that one TRS / CSI-RS is present.

[0091] In one embodiment, the bit width (number of bits) of the PI is configurable by the network. In an example embodiment, the network can configure the SSB grouping in an explicit manner, i.e., it can configure all SSBs in a cell in the same group, or it can form N groups of M SSBs and configure a corresponding number of bits to cover the number of groups. In this case, the network can configure the grouping with an N-bit presence indication, where each bit corresponds to a group, or the network can configure such a grouping where a 1-bit presence indication indicates whether all configured TRS / CSI-RS of the group (or grouped by the SSB) are present, or the 1-bit indication can be applied to all SSBs in the group.

[0092] In one embodiment, in particular, presence information / indicator (PI) is provided to a group of UEs. In this way, information indicating whether a given TRS / CSI-RS is present is provided to a group of UEs. This can be done before their paging occasion(s), for example in an early paging indication (EPI / PEI). As an alternative, a cell-wide PI can be used instead of or in addition to the per-group indication.

[0093] In one embodiment, the UE is configured with idle / inactive TRS / CSI-RS. In addition, the UE is informed, for example, via dedicated signaling (e.g., RRC release message) or via broadcast signaling (system information), whether the TRS / CSI-RS is constantly present, for example, at each opportunity and / or on each beam. For example, this notification can be performed via the PI.

[0094] In one embodiment, each presence indicator is associated with a timer that defines the validity period of the received presence indicator. For example, the value of the timer or counter can be configured in the SI / RRC signaling associated with the presence indication. As a non-limiting example, when the UE detects the presence indication (e.g., in the EPI / PEI), the UE can assume that the TRS / CSI-RS associated with the indication is present for the duration of the timer (e.g., N milliseconds, N seconds, or N paging cycles). In one embodiment, although the PI will no longer be set in subsequent (multiple) EPI transmissions while the timer is running, the UE can assume the presence of TRS / CSI-RS after being indicated by the network with a PI. When the timer expires, the UE cannot assume the presence of TRS / CSI-RS in the provided (multiple) opportunities. In one embodiment, the UE assumes that the configured TRS / CSI-RS timing (e.g., configured by RS configuration) is mapped to the actually transmitted SSB, i.e., the configured TRS / CSI-RS resource ID is mapped to the actually transmitted SSB in ascending / descending order, which is configured in "ssb-PositionsInBurst / groupPresence" or "ssb-PositionsInBurst / inOneGroup".

[0095] Let's start with Figure 7From the perspective of the signaling flow diagram in FIG. In step 700, the UE monitors SS / PBCH blocks from gNB 110. For example, these SS / PBCH blocks may be sent sequentially in multiple directions by gNB 110. The SS / PBCH blocks in step 700 may be sent periodically by the network. UE 120 may receive one or more SS / PBCH blocks. This may allow the UE to perform a cell search, for example, where the UE acquires time and frequency synchronization with the cell, decodes the cell ID, and extracts the MIB and SIB1. Each SSB may be identified by a unique number called an SSB index, and the identity of which SSB is detected depends on the UE's location. In step 702 / 204, after determining the RS configuration for the cell (e.g., the cell's SSBs), the network sends one or more RS configurations to the UE. In step 200 / 704, after determining the PI configuration for which the indicator exists, the network sends the PI configuration to the UE. In step 706, the network sends a packet information message to the UE. This can be done, for example, via the SSB-PositionsInBurst message and the IEs therein, or through a dedicated message. Let's assume that the message indicates that SSB#0 and SSB#1 are grouped together. In step 202 / 708, the UE receives the PI sent by gNB 110. The network may have already determined which SSB will carry the TRS / CSI-RS and set the PI accordingly. Let's assume that the PI indicates the presence of an RS for SSB#0. This indication can be a direct indication that SSB#0 carries an RS, or it can be an indirect indication that a certain RS configuration is used for RS transmission. Knowing the association between the RS configuration and the SSB, the UE can derive the ID of the SSB carrying the RS. Thereafter, in step 206 / 710, the UE can determine that the configured TRS / CSI-RS is present in SSB#0 and SSB#1. The presence in SSB#1 can be attributed to the grouping association between SSB#0 and SSB#1. The network can then transmit the reference signal accordingly. As described above, the SSBs of step 700 can be periodically transmitted by the network. For example, in subsequent transmissions of SSBs after step 710, the network node 110 may transmit reference signals in SSB#0 and SSB#1, but not in SSB#2 and SSB#3 (although SSB#2 and SSB#3 may or may not be transmitted).

[0096] From the perspective of a network node (such as gNB 110), Figure 8An embodiment is depicted in FIG. In step 800, gNB 110 determines a presence indicator configuration, which defines how a UE receiving a PI will interpret the presence indicator. Based on the configuration, the presence indicator indicates whether a set of one or more reference signal opportunities associated with at least one SSB of a cell carries a reference signal. In step 802, gNB 110 determines at least one reference signal configuration, each reference signal configuration indicating at least one reference signal opportunity of a cell. In step 804, the presence indicator and at least one reference signal configuration are sent to the user equipment. Optionally, the network may also send the PI configuration to the UE. Then, in step 806, based on the presence indicator configuration, the presence indicator, and the at least one reference signal configuration, gNB 110 may begin transmitting reference signals in the cell.

[0097] like Figure 9 The illustrated embodiment provides an apparatus 10 comprising a control circuit system (CTRL) 12, such as at least one processor and at least one memory 14 comprising computer program code (software), wherein the at least one memory and the computer program code (software) are configured to, together with the at least one processor, cause the apparatus to implement any of the processes described above. The memory may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The memory may include a database for storing data.

[0098] In one embodiment, the apparatus 10 may comprise a terminal device of a communication system, such as a user terminal (UT), a computer (PC), a laptop computer, a tabloid computer, a cellular phone, a mobile phone, a communicator, a smartphone, a palmtop computer, a mobile transport device (such as a car), a household appliance, or any other communication device generally referred to as a UE in the specification. Alternatively, the apparatus is included in such a terminal device. In addition, the apparatus may be or may comprise a module (to be attached to the UE) that provides connectivity, such as a plug-in unit, a "USB dongle", or any other type of unit. The unit may be installed inside the UE, attached to the UE via a connector, or even wirelessly attached to the UE.

[0099] In one embodiment, the apparatus 10 is a UE 120, or is included in a UE 120. The apparatus may be caused to perform some functions of the above-described procedures.

[0100] The apparatus may further include a radio interface (TRX) 16, which includes hardware and / or software for implementing communication connections according to one or more communication protocols. For example, the TRX may provide the apparatus with communication capabilities to access a wireless access network.

[0101] The apparatus may further comprise a user interface 18 comprising, for example, at least one keyboard, microphone, touch display, display, speaker, etc. A user may use the user interface to control the device.

[0102] According to any embodiment, the control circuit system 12 may include a PI determination circuit system 20 for determining a PI configuration and for extracting the PI from the network, and for determining which RS opportunities carry reference signals. According to any embodiment, the control circuit system 12 may also include an RS decoding circuit system 22 for decoding the RS opportunity when it is detected that the RS opportunity in question carries a reference signal.

[0103] like Figure 10 The illustrated embodiment provides an apparatus 50 comprising a control circuit system (CTRL) 52, such as at least one processor and at least one memory 54 comprising computer program code (software), wherein the at least one memory and the computer program code (software) are configured to, together with the at least one processor, cause the apparatus to implement any of the processes described above. The memory may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The memory may include a database for storing data.

[0104] In one embodiment, the apparatus 50 may be a network node, or be included in a network node, such as a 5G gNB / gNB-CU / gNB-DU. In one embodiment, the apparatus is a network node 110, or is included in a network node 110. The apparatus may be configured to perform some functions of the above-described procedures.

[0105] In one embodiment, a CU-DU (central unit-distributed unit) architecture is implemented. In this case, the device 50 may be included in a central unit (e.g., a control unit, an edge cloud server, a server), which is operably coupled to a distributed unit (e.g., a remote radio head / node) (e.g., via a wireless or wired network). That is, the central unit (e.g., an edge cloud server) and the radio node may be independent devices that communicate with each other via a radio path or via a wired connection. Alternatively, they may be in the same entity that communicates via a wired connection, etc. The edge cloud or edge cloud server may serve multiple radio nodes or radio access networks. In one embodiment, at least some of the processes described may be performed by a central unit. In another embodiment, the device may alternatively be included in a distributed unit, and at least some of the processes described may be performed by the distributed unit. In one embodiment, the execution of at least some of the functions of the device 50 may be shared between two physically separate devices (DU and CU), which form one operating entity. Therefore, it can be seen that the device depicts an operating entity comprising one or more physically separate devices for performing at least some of the described processes. In one embodiment, the device controls the execution of the process regardless of the location of the device and the location where the process / function is performed.

[0106] The device may also include a radio interface (TRX) 56, which includes hardware and / or software for implementing a communication connection according to one or more communication protocols. For example, the TRX may provide the device with communication capabilities to access a wireless access network. The device may also include a user interface 58, which may include, for example, at least one keyboard, microphone, touch display, display, speaker, etc. A user may use the user interface to control the device.

[0107] According to any embodiment, the control circuitry 52 may include presence indicator configuration determination circuitry 60 for determining the configuration of the PI. According to any embodiment, the control circuitry 12 may include reference signal configuration determination circuitry 62, for example, for determining the configuration of reference signals and the mapping between SSB and RS opportunities. According to any embodiment, the control circuitry 12 may include reference signal transmission circuitry 64, for example, for transmitting reference signals in a cell.

[0108] In one embodiment, an apparatus for implementing at least some of the described embodiments includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to implement the functionality according to any of the described embodiments. According to one aspect, when the at least one processor executes the computer program code, the computer program code causes the apparatus to implement the functionality according to any of the described embodiments. According to another embodiment, an apparatus for implementing at least some of the embodiments includes at least one processor and at least one memory including computer program code, wherein the at least one processor and the computer program code perform at least some of the functionality according to any of the described embodiments. Thus, the at least one processor, the memory, and the computer program code form a processing component for implementing at least some of the described embodiments. According to yet another embodiment, an apparatus for implementing at least some of the embodiments includes circuitry including at least one processor and at least one memory including computer program code. When activated, the circuitry causes the apparatus to perform at least some of the functionality according to any of the described embodiments.

[0109] As used in this application, the term 'circuitry' may refer to one or more or all of the following: (a) hardware circuitry implementations only (such as implementations using only analog and / or digital circuitry), and (b) combinations of hardware circuitry and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of a hardware processor(s) with software, including digital signal processor(s), software, and memory(s), which work together to cause a device (such as a mobile phone or server) to perform various functions, and (c) hardware circuitry and / or processor(s), such as microprocessor(s) or portions of microprocessor(s), which require software (e.g., firmware) to operate but may not be present when not required for operation. This definition of 'circuitry' applies to all uses in this application. As another example, as used in this application, the term 'circuitry' would also encompass an implementation of only a processor(s) or portion of a processor and its accompanying software and / or firmware. For example, the term 'circuitry' would also cover, if applicable to the particular element, a baseband integrated circuit or an applications processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, cellular network equipment, or other computing or networking equipment.

[0110] In one embodiment, at least some of the processes can be implemented by an apparatus including corresponding components for implementing at least some of the processes. Some example components for implementing these processes may include at least one of the following: a detector, a processor (including dual-core and multi-core processors), a digital signal processor, a controller, a receiver, a transmitter, an encoder, a decoder, a memory, RAM, ROM, software, firmware, a display, a user interface, a display circuit system, a user interface circuit system, a user interface software, a display software, a circuit, an antenna, an antenna circuit system, and a circuit system.

[0111] The techniques and methods described herein can be implemented using various components. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For hardware implementations, the apparatus(es) of the embodiments can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be implemented using modules (e.g., processes, functions, etc.) of at least one chip set that performs the functions described herein. The software code can be stored in a memory unit and executed by the processor. The memory unit can be implemented within the processor or external to the processor. In the latter case, it can be communicatively coupled to the processor via various components known in the art. In addition, the components of the systems described herein can be rearranged and / or supplemented by additional components to facilitate implementation of various aspects thereof, and as will be understood by those skilled in the art, they are not limited to the precise configurations illustrated in the given figures.

[0112] The described embodiments may also be implemented in the form of a computer process defined by a computer program or a portion thereof. Embodiments of the method may be implemented by executing at least a portion of a computer program comprising corresponding instructions. The computer program may be in source code form, object code form, or some intermediate form, and it may be stored in a carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or processor. For example, the computer program medium may be, for example, but not limited to, a recording medium, a computer memory, a read-only memory, an electrical carrier signal, a telecommunications signal, and a software distribution package. The computer program medium may be a non-transient medium. The coding of the software for implementing the illustrated and described embodiments is fully within the capabilities of those of ordinary skill in the art.

[0113] Although the present invention has been described above with reference to the examples according to the accompanying drawings, it is obvious that the present invention is not limited thereto, but may be modified in various ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate rather than limit the embodiments. It will be apparent to those skilled in the art that, as technology advances, the concepts of the present invention may be implemented in various ways. In addition, it will be clear to those skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

1. A device for communication, comprising: at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: determining a presence indicator configuration, the presence indicator configuration defining how to interpret a presence indicator, wherein, based on the configuration, the presence indicator indicates: whether at least one set of one or more configured reference signal opportunities of the cell carries a reference signal; obtaining the presence indicators from a base station, wherein each presence indicator is associated with a timer, the timer defining a validity period for each of the received presence indicators; obtaining at least one reference signal configuration from the base station, each reference signal configuration indicating at least one configured reference signal opportunity; and Based on the presence indicator and the determined presence indicator configuration, it is determined whether a given reference signal opportunity indicated by the at least one reference signal configuration carries a reference signal. 2 . The apparatus according to claim 1 , wherein the apparatus is a user equipment in a radio resource control (RRC) idle state or an inactive state.

3. The apparatus according to claim 1 , wherein the reference signal comprises: A tracking reference signal is sent from the base station in a downlink.

4. The device according to claim 1, wherein Determining the presence indicator configuration includes receiving information indicative of the presence indicator configuration from the base station.

5. The device according to claim 1, wherein Based on the presence indicator configuration, the at least one set includes all reference signal opportunities in the configured reference signal opportunities associated with the synchronization signal block SSB of the cell, and the presence indicator indicates that: all reference signal opportunities in the configured reference signal opportunities associated with the SSB of the cell or no configured reference signal opportunity carries a reference signal.

6. The device according to claim 1, wherein Based on the presence indicator configuration, the at least one set includes a subset of configured reference signal opportunities associated with at least one synchronization signal block SSB of the cell, and the presence indicator indicates whether the subset carries a reference signal, the subset including at least one but not all configured reference signal opportunities of the cell.

7. The device according to claim 6, wherein According to the presence indicator configuration, the presence indicator indicates at least one of: at least one SSB of the cell where the reference signal is present, but not all SSBs; or at least one reference signal configuration of the cell according to which the reference signal is sent, but not all reference signal configurations.

8. The device according to claim 1, wherein The at least one memory and the computer program code are configured to, with the at least one processor, further cause the apparatus to: detecting a channel on which the presence indicator is received; Associating the channel with at least one synchronization signal block (SSB); Determining the at least one set of configured reference signal opportunities corresponding to the presence indicator includes those configured reference signal opportunities included in the associated at least one SSB.

9. The device according to claim 1, wherein The at least one memory and the computer program code are configured to, with the at least one processor, further cause the apparatus to: associating at least one synchronization signal block (SSB) with the obtained at least one reference signal configuration; Based on the presence indicator and the presence indicator configuration, it is determined that a reference signal from the base station is present in the at least one SSB.

10. The device according to claim 1, wherein The presence indicator is received in an earlier paging message.

11. The device according to claim 1, wherein The presence indicator is received in downlink control information DCI on a physical downlink control channel PDCCH.

12. The device according to claim 1, wherein The at least one memory and the computer program code are configured to, with the at least one processor, further cause the apparatus to: determining, based on the presence indicator and the presence indicator configuration, that the at least one set including only the configured reference signal opportunities in a first synchronization signal block (SSB) carries a reference signal; A reference signal is determined to also be present in at least one other SSB associated with the same SSB group as the first SSB.

13. The device according to claim 1, wherein The at least one memory and the computer program code are configured to, with the at least one processor, further cause the apparatus to: determining, based on the presence indicator and the presence indicator configuration, that the at least one set carries reference signals, the at least one set comprising only configured reference signal opportunities based on a first reference signal configuration; The presence of a reference signal is also determined based on at least one other reference signal configuration, the at least one other reference signal configuration being associated with the same reference signal configuration group as the first reference signal configuration.

14. The apparatus of claim 1, wherein the presence indicator comprises only a single bit.

15. The device according to claim 1, wherein Based on the presence indicator configuration, when the presence indicator comprises a plurality of bits, each bit indicates whether a given subset of configured reference signal opportunities carries a reference signal, wherein each subset comprises at least one but not all configured reference signal opportunities of the cell.

16. The device according to claim 1, wherein The configured reference signal opportunities defined by a given subset are all included in the same synchronization signal block SSB group, or reference signal configuration group.

17. The device according to claim 1, wherein The grouping of the reference signal configurations is based on an explicit configuration received by the apparatus from the base station.

18. An apparatus for communication, comprising: at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: determining a presence indicator configuration, the presence indicator configuration defining how a user equipment is to interpret a presence indicator, wherein, based on the configuration, the presence indicator indicates: whether at least one set of one or more configured reference signal opportunities of a cell carries a reference signal; determining at least one reference signal configuration, each reference signal configuration indicating at least one configured reference signal opportunity for the cell; sending the presence indicators and the at least one reference signal configuration to the user equipment, wherein each presence indicator is associated with a timer, the timer defining a validity period for each of the received presence indicators; A reference signal is sent in the cell based on the presence indicator configuration, the presence indicator, and the at least one reference signal configuration.

19. A method for communication, comprising: determining a presence indicator configuration, the presence indicator configuration defining how to interpret a presence indicator, wherein, based on the configuration, the presence indicator indicates: whether at least one set of one or more configured reference signal opportunities of the cell carries a reference signal; obtaining the presence indicators from a base station, wherein each presence indicator is associated with a timer, the timer defining a validity period for each of the received presence indicators; obtaining at least one reference signal configuration from the base station, each reference signal configuration indicating at least one configured reference signal opportunity; and Based on the presence indicator and the determined presence indicator configuration, it is determined whether a given reference signal opportunity indicated by the at least one reference signal configuration carries a reference signal.

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