Predefined composite synchronization signal set

Abstract

Systems and methods are disclosed that relate to the configuration and use of signal and / or channel composites in a cellular communications system. In one embodiment, a method performed by a User Equipment (UE) comprises obtaining information that configures the UE with a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The method further comprises obtaining, from a Radio Access Network (RAN) node, an indication of one of the set of signal and / or channel composites and operating in accordance with the one of the set of signal and / or channel composites. In this manner, reduced signaling overhead and faster adaptation is provided for scenarios supporting different use cases.

Description

[0001] P111026W001 1

[0002] PREDEFINED COMPOSITE SYNCHRONIZATION SIGNAL SET

[0003] Technical Field

[0004] The present disclosure relates to a wireless communications system and, more specifically, to configuration of a device for transmission and / or reception of wireless signals and / or channels in a wireless communications system.

[0005] Background

[0006] In 3rdGeneration Partnership Project (3GPP) specifications, optimizing energy performance is often designed as minimizing the energy consumption for a set of performance requirements (e.g., user throughput, capacity, latency, etc.). An energy efficient standard can only enable low energy consumption operation by creating opportunities to deactivate hardware components for long periods of time and fractions of time.

[0007] One problem in the design of 5thGeneration (5G) New Radio (NR) that often prevents energy saving optimizations is that several functions with vastly different requirements are coupled together via the broadcasted Synchronization Signal Block (SSB) signal, see Figure 1. It may seem like a clever idea to reuse signals for multiple purposes instead of defining separate signals for distinct functions, but what often happens is that the function with most stringent requirements defines the design. Some functions (e.g., connected mode mobility) require fine spatial resolution while other functions (e.g., system information broadcast and paging) do not. In 5G NR, this has resulted in a design where paging and system information broadcast is repeated in every beam, on every carrier, and from every Transmission and Reception Point (TRP). In addition, changing (e.g., turning off, changing the periodicity, changing the beam, changing power, etc.) one signal impacts all connected functions. In practice, this leads to a static operation where nothing is ever changed, and everything is constantly configured for a worst-case scenario.

[0008] When designing complex systems such as the 6thGeneration (6G) system, it is often better to follow a design principle known as "separation of concerns." This ensures that each function can be independently optimized without any "requirement creep" and without much understanding or consideration of any other functions in the system. For example, see Figure 2 which illustrates that, in 6G, distinct function such as P111026W001 2 idle mode System Information (SI) broadcast (left), measurements related to target cells (middle), and additional signals related to the serving cells (right) should rely on different signals, thereby enabling independent optimization of each function.

[0009] From the perspective of minimizing the network energy consumption, it is desirable to have a system that allows for low idle mode consumption. This can be achieved by e.g.:

[0010] • a design that allows for SI broadcast transmissions from a subset of the TRPs in the network. This implies that not all TRPs will have an idle mode SSB and that not all TRPs need to participate in SI broadcast. One direct consequence of this is that the idle mode SSB cannot be used to identify all TRPs, and hence it cannot be effectively used for e.g., connected mode mobility functions.

[0011] • SI transmission can be identical from two or more TRPs. The Signal to Interference plus Noise Ratio (SINR) gain of transmitting SI broadcast using Single Frequency Network (SFN) transmission can be well above 25 decibels (dB) in a dense deployment (Inter-Site Distance (ISD) less than 500 meters). This implies that the idle mode SSB cannot uniquely identify the TRPs in the network.

[0012] This has consequences for how connected mode mobility is handled, primarily for the better. Mobility measurements on target cells hence need to be based on a different signal than the idle mode SSB, e.g., on a new downlink (DL) mobility reference signal. The current best guess is that this new 6G DL mobility reference signal will be like an idle mode SSB signal since this may simplify the User Equipment (UE) implementation.

[0013] Mobility measurement can also be based on uplink (UL) transmissions (from the UEs to the TRPs), based on secondary carrier predictions, derived from UE positioning, or any combination thereof. It would be a mistake to primarily rely on a periodic downlink reference signals for mobility in 6G since a good mobility toolbox is much larger than that.

[0014] In addition, some advanced use-cases (e.g., Layer 1 (LI) mobility) may also require a new synchronization signal for connected mode data transmission and measurements targeting the serving cell.

[0015] The concept of lean design, i.e., to minimize transmission not related to data transfers, was introduced in 5G NR. This has been a tremendous success, enabling much larger energy savings due to micro-sleep transmission than any previous generation. For 6G, 3GPP should continue to build on this success story and do more of P111026W001 3 what has proven to work well in 5G. The 6G lean design concept can be summarized as follows:

[0016] • Enhanced lean design in time domain'. This implies further reducing the time-domain footprint of idle mode signals, to align discontinuous reception on the UE side with discontinuous transmission on the NW side, and vice versa, and to further enhance opportunities for micro-sleep reception in addition to micro-sleep transmission. To some extent, this work has already started in the ongoing 3GPP WI on NW Energy Efficiency targeting Rel-18 and Rel-19.

[0017] • Extending lean design to the node / TRP domain'. Here the idle-mode and active mode separation is key. System information transmission can occur from a sub-set of the TRPs and more than one TRP can transmit system information using SFN transmission. Nodes with no responsibility for SI broadcast can be activated and deactivated with no impact on the SI broadcast and other idle mode functions.

[0018] • Extend lean design to the frequency domain-. In 6G we should further improve solutions that enable Si-free carriers. Also, not all carriers need downlink mobility reference signal (RS) transmissions (and mobility RS signals on some carriers can have extended periodicity). In 6G there will therefore be different carriers that are configured differently.

[0019] An important aspect of the 6G air interface is the separation of idle and connected states to extend the ultra-lean design from the time domain (i.e., very few always-on signals) to the spatial and frequency domains to improve energy efficiency (among other things), see Figure 3. To achieve this, separate signals are defined for idle and connected mode procedures. To simplify UE implementation, it is beneficial if the signals used for idle and connected mode follow a similar structure. This can be achieved by defining multiple types of SSBs. Based on this basic structure, different types of SSB transmissions tailored for different purposes can be defined, e.g.:

[0020] • Idle mode SSB (I-SSB): I-SSB is used in idle mode in an analogous way as in NR.

[0021] It is transmitted on the idle mode search grid (which can be identical to the one used in NR or a sparser one). The Master Information Block (MIB) field in the I- SSB provides information on how to receive (idle-mode) system information. In 5G NR terminology, this is like the Cell-Defining SSB (CD-SSB).

[0022] • Mobility SSB (M-SSB): M-SSB is used for mobility in connected mode. It is transmitted periodically, a-periodically, in bursts, or not at all, as dynamically P111026W001 4 decided by the network. This is a downlink signal that may be used for mobility measurements. The MIB in the M-SSB does not point to any system information, but preferably contains an identity associated with a specific beam or TRP in the network. The UE does not need to be configured with a specific list of M-SSBs to search for but can, given some information about where in the time-frequency resource space to search, "blindly" find the M-SSBs transmitted, read, and report its identity (like how it can detect any 5G SSB being present in 5G).

[0023] • Extended periodicity SSB (E-SSB): E-SSB is not detectable by idle mode UEs, but is otherwise like the I-SSB. It is periodically transmitted with a long (extended) periodicity.

[0024] • Dynamic or Dedicated SSB (D-SSB): D-SSB is, in some use cases, a special signal that may be used as a Quasi Co-Location (QCL) root for serving cell measurements and functions in connected mode.

[0025] Although multiple SSB types have been described above, not all of them are present in all types of deployments. Also, please note that these are only examples and that a future 6G Radio Access Technology (RAT) may define different signals with different names.

[0026] In contrast to having such different SSBs, 5G NR uses the same signal (the CD- SSB) as QCL-root for both idle mode handling, mobility measurements, and serving cell measurements, which creates undesirable dependencies between idle / inactive and connected mode.

[0027] Figure 4 illustrates the design of the SSB in 5G NR. As illustrated in Figure 4, the SSB in NR consists of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS) and a Physical Broadcast Channel (PBCH). The UE can derive time and frequency synchronization from the PSS and SSS as well as the Physical Cell Identity (PCID) that is encoded in the sequence used. The UE blindly detect the sequences from a subset of pre-defined options. The PBCH consist of a Demodulation Reference Signal (DMRS) and payload. The DMRS sequence used for PBCH is used to derive frame timing for the SSB. A UE not knowing the frame timing blindly detects what DMRS sequence is used. Part of the frame-timing may also be explicitly included in the data part of the PBCH. P111026W001 5

[0028] Systems and methods are disclosed that relate to the configuration and use of signal and / or channel composites in a cellular communications system. In one embodiment, a method performed by a User Equipment (UE) comprises obtaining information that configures the UE with a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The method further comprises obtaining, from a Radio Access Network (RAN) node, an indication of one of the set of signal and / or channel composites and operating in accordance with the one of the set of signal and / or channel composites. In this manner, reduced signaling overhead and faster adaptation is provided for scenarios supporting different use cases.

[0029] In one embodiment, each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite is a synchronization signal block (SSB) that contains a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH).

[0030] In one embodiment, for each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite contains a PSS and an SSS.

[0031] In one embodiment, the at least one additional reference signal or channel comprises: (a) a downlink reference signal, (b) an uplink reference signal, (c) a downlink channel, (d) an uplink channel, or (e) a combination of any two or more of (a)-(d).

[0032] In one embodiment, the operating in accordance with the one of the set of signal and / or channel composites comprises receiving the synchronization signal component comprised in the one of the set of signal and / or channel composites. In one embodiment, the one of the set of signal and / or channel composites further comprises a downlink channel, and operating in accordance with the one of the set of signal and / or channel composites comprise receiving the downlink channel comprised in the one of the set of signal and / or channel composites. In another embodiment, the one of the set of signal and / or channel composites further comprises a downlink reference signal, and operating in accordance with the one of the set of signal and / or channel composites P111026W001 6 comprise receiving the downlink reference signal comprised in the one of the set of signal and / or channel composites. In one embodiment, the one of the set of signal and / or channel composites further comprises an uplink reference signal, and operating in accordance with the one of the set of signal and / or channel composites comprise transmitting the uplink reference signal comprised in the one of the set of signal and / or channel composites.

[0033] In one embodiment, obtaining the information that configures the UE with the set of signal and / or channel composites comprises receiving the information that configures the UE with the set of signal and / or channel composites from a RAN node. In one embodiment, receiving the information that configures the UE with the set of signal and / or channel composites from the RAN node comprises receiving at least part of the information via a Radio Resource Control (RRC) configuration while in a connected mode state. In one embodiment, receiving the information that configures the UE with the set of signal and / or channel composites from the RAN node comprises receiving at least part of the information via a message in a broadcasted system information block.

[0034] In one embodiment, at least part of the information that configures the UE with the set of signal and / or channel composites is predefined via a standard specification.

[0035] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication from the RAN node via an information field contained in a physical broadcast channel transmitted in direct association with the synchronization signal component.

[0036] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication from the RAN node via an information field contained in a master information block.

[0037] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication from the RAN node in a downlink control information (DCI) field contained in a physical downlink control channel.

[0038] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication from the RAN node in medium access control (MAC) control element (CE) field. P111026W001 7

[0039] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication from the RAN node in an RRC message.

[0040] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication via reception of a predefined synchronization signal block (SSB) type on a predefined frequency and time resource.

[0041] In one embodiment, obtaining the indication of one of the set of signal and / or channel composites comprises receiving the indication via a UE blind detection procedure.

[0042] Corresponding embodiments of a UE are also disclosed. In one embodiment, a UE is adapted to obtain information that configures the UE with a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The UE is further adapted to obtain, from a RAN node, an indication of one of the set of signal and / or channel composites and operate in accordance with the one of the set of signal and / or channel composites.

[0043] In one embodiment, a UE comprises a transmitter, a receiver, and processing circuitry associated with the transmitter and the receiver. The processing circuitry is configured to cause the UE to obtain information that configures the UE with a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The processing circuitry is further configured to cause the UE to obtain, from a RAN node, an indication of one of the set of signal and / or channel composites and operate in accordance with the one of the set of signal and / or channel composites.

[0044] Embodiments of a method performed by a RAN node for a RAN of a cellular communications system are also disclosed. In one embodiment, a method performed by a RAN node for a RAN of a cellular communications system comprises transmitting, to a UE, an indication of one of a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization P111026W001 8 signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The method further comprises operating in accordance with the one of the set of signal and / or channel composites.

[0045] Corresponding embodiments of a RAN node for a RAN of a cellular communications system are also disclosed. In one embodiment, a RAN node for a RAN of a cellular communications system is adapted to transmit, to a UE, an indication of one of a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The RAN node is further adapted to operate in accordance with the one of the set of signal and / or channel composites.

[0046] In one embodiment, a RAN node for a RAN of a cellular communications system comprises processing circuitry configured to cause the RAN node to transmit, to a UE, an indication of one of a set of signal and / or channel composites, wherein each composite of the set of signal and / or channel composites comprises a synchronization signal component and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel. The processing circuitry is further configured to cause the RAN node to operate in accordance with the one of the set of signal and / or channel composites.

[0047] Brief of the

[0048] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0049] Figure 1 is an illustration that shows that, in 5thGeneration (5G) New Radio (NR), several functions with vastly different requirements are coupled together via the broadcasted Synchronization Signal Block (SSB) signal;

[0050] Figure 2 illustrates that, in 6thGeneration (6G), distinct function such as idle mode System Information (SI) broadcast (left), measurements related to target cells P111026W001 9

[0051] (middle), and additional signals related to the serving cells (right) should rely on different signals, thereby enabling independent optimization of each function;

[0052] Figure 3 illustrates an important aspect of the 6G air interface, which is the separation of idle and connected states to extend the ultra-lean design from the time domain (i.e., very few always-on signals) to the spatial and frequency domains to improve energy efficiency (among other things);

[0053] Figure 4 illustrates the design of the SSB in 5G NR;

[0054] Figure 5 illustrates one example of a cellular communications system in which embodiments of the present disclosure may be implemented;

[0055] Figure 6 illustrates an example of a set of signal and / or channel composites in accordance with an embodiment of the present disclosure;

[0056] Figure 7 illustrates two additional examples of a set of signal and / or channel composites in accordance with an embodiment of the present disclosure;

[0057] Figure 8 illustrates one example of an indexable table (e.g., using 3 bits) of the predefined set of signal and / or channel composites illustrated in the examples of Figures 6 and 7;

[0058] Figure 9 illustrates the operation of a User Equipment (UE) and a Radio Access Network (RAN) node (e.g., a base station) in accordance with embodiments of the present disclosure;

[0059] Figure 10 is a schematic block diagram of a RAN node according to some embodiments of the present disclosure;

[0060] Figure 11 is a schematic block diagram that illustrates a virtualized embodiment of the RAN node of Figure 10 according to some embodiments of the present disclosure;

[0061] Figure 12 is a schematic block diagram of the RAN node of Figure 10 according to some other embodiments of the present disclosure;

[0062] Figure 13 is a schematic block diagram of a UE according to some embodiments of the present disclosure; and

[0063] Figure 14 is a schematic block diagram of the UE of Figure 13 according to some other embodiments of the present disclosure. P111026W001 10

[0064] Detailed Description

[0065] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0066] Radio Node: As used herein, a "radio node" is either a RAN node or a User Equipment (UE).

[0067] Radio Access Network (RAN) Node: As used herein, a "RAN node" or "radio access node" or "radio network node" or "radio access network node" is any node in a RAN of a cellular communications network. Some examples of a RAN node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network or similar node in a 6thGeneration (6G) RAN), a high-power or macro base station, a low- power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station or a network node that implements a Distributed Unit (DU) or Central Unit (CU) of a base station in the case of a split architecture) or a network node that implements part of the functionality of some other type of RAN node.

[0068] Communication Device: As used herein, a "communication device" is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehiclemounted mobile device, enabled to communicate voice and / or data via a wireless or wireline connection.

[0069] User Equipment (UE): One type of communication device is a UE. As used herein, a UE is a wireless communication device, which may be any type of wireless P111026W001 11 device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a UE include, but are not limited to: a UE in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (loT) device. Such UEs may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The UE may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and / or data via a wireless connection.

[0070] Network Node: As used herein, a "network node" is any node that is either part of the RAN or the core network of a cellular communications network / system.

[0071] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0072] Note that, in the description herein, reference may be made to the term "cell"; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0073] There are certain challenges that exist for wireless communications systems when using existing solutions for synchronization signal transmission. As discussed above, the 3GPP 6thGeneration (6G) Radio Access Technology (RAT) will likely have separate Synchronization Signal Block (SSB) signals for idle mode functions and connected mode functions. There can be more than two SSB types for 6G. Furthermore, 3GPP is currently discussing on-demand SSB transmissions for Release 19. In addition, there are many other different signals that can be provided a-periodically and on- demand already in 5G NR (e.g. Channel State Information (CSI) Reference Signal (CSI- RS) for mobility, CSI-RS for Multiple Input Multiple Output (MIMO) transmission, Tracking Reference Signal (TRS), SSB, Sounding Reference Signal (SRS), Physical Random Access Channel (PRACH), Scheduling Request (SR), etc.) and one can assume that similar signals will be defined for on-demand and aperiodic transmissions for 6G.

[0074] Different use cases require different sequences of events and on-demand signal transmissions and channel usages. Some examples are: P111026W001 12

[0075] • Fast carrier / Secondary Cell (SCell) activation,

[0076] • UE wakes up after long Discontinuous Reception (DRX) period,

[0077] • Transmission with dedicated transmission of beamformed synchronization signal,

[0078] • Target cell mobility measurements

[0079] • Etc.

[0080] Configuring aperiodic transmissions for all different use cases can become complex considering all possible combinations and the required signaling overhead can quickly become large.

[0081] Systems and methods are disclosed herein that address the aforementioned and / or other challenges. In some embodiments, a set of signal and / or channel composites is predefined or configured to a UE. The set of signal and / or channel composites consists of different signal and / or channel composites, e.g., for different purposes or events. As used herein, a "signal and / or channel composite" is an aggregation of one or more signals, one or more physical channels, or a combination thereof. The aggregation may be, for example, with a known or configured time offset, a known or configured frequency offset, or a known or configured time and frequency offset. In the preferred embodiments of the present disclosure, each signal and / or channel composite in the set includes a synchronization signal component (e.g., a Primary Synchronization Signal (PSS) and / or a Secondary Synchronization Signal (SSS), or an SSB, which includes a PSS, SSS, and Physical Broadcast Channel (PBCH)), where at least some of the signal and / or channel composites include different types of synchronization signal components (e.g., different SSB types). In addition, at least one of the signal and / or channel composites in the set further includes at least one additional signal or channel (e.g., one or more downlink (DL) reference signals (e.g., TRS, CSI-RS, or the like), one or more DL channels (e.g., a Physical Downlink Control Channel (PDCCH), a Physical Downlink Shared Channel (PDSCH), and / or the like), one or more uplink (UL) reference signals (e.g., SRS), one or more UL channels (e.g., Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), and / or the like), or any combination thereof.

[0082] One of the set of signal and / or channel composites is activated at the UE. In one embodiment, this activation is via signaling received at the UE from a network node, where this signaling may be, for example: P111026W001 13

[0083] • explicit signaling, e.g. a field in the MIB, a Downlink Control Information (DCI), a Medium Access Control (MAC) Control Element (CE), a Radio Resource Control (RRC) control element, an RRC configuration message, or the like; or

[0084] • implicit signaling, e.g. a timing and / or frequency position of a signal received by the UE (e.g., an SSB transmission), UE blind detection, etc.

[0085] The UE (and the network node) then operate in accordance with (e.g., transmit and / or receive signals and / or channels in accordance with) the activated signal and / or channel composite.

[0086] Embodiments of the present disclosure may be used, e.g., to

[0087] • indicate to a UE (e.g., in the MIB) why the network has chosen to transmit an on-demand SSB transmission (e.g., a D-SSB or an M-SSB transmission), and / or

[0088] • indicate to the UE what additional signals and channels will follow next and what actions the network expects the UE to do when receiving this on-demand SSB transmission.

[0089] Embodiments of the present disclosure may provide a number of advantages over existing solutions. For example, embodiments of the present disclosure provide reduced signaling overhead and faster adaptation in some scenarios.

[0090] Figure 5 illustrates one example of a cellular communications system 500 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 500 is a 5G system (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC) or a 6G system including a 6G RAN (i.e., a RAN that operates in accordance with a 6G RAT) and a 6G core network. In this example, the RAN includes base stations 502-1 and 502-2, which in the 5GS include NR base stations (gNBs) and in the 6GS include 6G base stations, controlling corresponding cells 504-1 and 504-2. The base stations 502-1 and 502-2 are generally referred to herein collectively as base stations 502 and individually as base station 502. Likewise, the cells 504-1 and 504-2 are generally referred to herein collectively as cells 504 and individually as cell 504. While not illustrated, the base stations 502 may be implemented in a distributed manner such that each base station 502 is formed of multiple RAN nodes (e.g., a Central Unit (CU) and one or more Distributed Units (DUs) or TRPs). The cellular communications system 500 also includes a core network 510, which in the 5GS is referred to as the 5GC and in the 6G system P111026W001 14 may be referred to as the 6G core. The base stations 502 are connected to the core network 510.

[0091] The base stations 502 provide wireless access to UEs 512 in the corresponding cells 504.

[0092] In accordance with embodiments of the present disclosure, a set of signal and / or channel composites is predefined or configured to a UE 512. The set of signal and / or channel composites consists of different signal and / or channel composites, e.g., for different purposes or events. In this regard, Figure 6 illustrates an example of a set of signal and / or channel composites in accordance with an embodiment of the present disclosure. As illustrated in Figure 6, the exemplary set includes signal and / or channel composites labeled (a) to (f) that are known by both the network and the UE. Note that, in this example, all the entries (i.e., all composites) in the set contain at least a synchronization signal component (e.g., a SSB). The composite labeled (a) consists of only a synchronization signal component and may be included in the set as a fallback option or default option where no additional signals are included.

[0093] The composite labeled (b) consists of a synchronization signal component (SSB in this example) directly followed by a TRS. In some embodiments, the timing and / or frequency spacing between the synchronization signal component and the TRS signal component is explicitly defined (e.g., a TRS comprising consecutive symbols in the frequency domain and a frequency offset of Nz will be provided K symbols after the reception of the SSB). This composite can e.g. be used to very quickly enable a UE to enable fine timing towards a new TRP or a new carrier.

[0094] The composite labeled (c) is similar to the composite labeled (b) but it further contains a PDCCH component that can further be used to dynamically schedule a PDSCH transmission. The relative time and / or frequency position of the PDCCH in relation to the synchronization signal component and / or the TRS can be further configured. This composite signal combination can, e.g., be used to very quickly enable a UE to receive a downlink data transmission from a new TRP or from a new carrier.

[0095] The composite labeled (d) has no TRS component and it may be used to reduce the overhead of the TRS and thereby increase the spectral efficiency when the UE timing is already good enough to not significantly impact performance of subsequent transmission. This can, e.g., be used to quickly continue transmitting downlink data towards a UE after a short interruption or to transmit data with relaxed synchronization P111026W001 15 requirements, e.g. with restrictions on modulation order and / or number of spatial layers.

[0096] The composite labeled (e) consists of a long train of multiple synchronization signal components that are stacked consecutively in the time domain. This type of "synchronization burst" can be useful to help a UE that wakes up from a very long DRX cycle and hence has very poor knowledge of the system timing to acquire the system timing very quickly. This can reduce the need for transmitting dense periodic synchronization signals in the time domain to achieve the same thing, and hence this can reduce the network energy consumption. Alternatively, if a sparse periodicity of the synchronization signal is used to enable low network energy usage, then the UE latency and battery consumption will increase. By using on-demand or a-periodic synchronization signal burst as in the example composite (e), the UE never needs to search for a sparse synchronization signal and hence the UE battery life can be extended and the user plane latency is reduced in case there is any data to transmit to or from the UE when it wakes up. This would also be beneficial for a UE employing an analog beamforming in the receiver to be able to quickly acquire a good receive (Rx) beam.

[0097] The composite labeled (f) may, e.g., be suitable for accurate (e.g., wideband) mobility measurements. It can also be suitable to enable the UE to quickly obtain accurate downlink CSI towards a serving cell.

[0098] The examples provided in Figure 6 all consist of only physical downlink signals and channels. However, the set of signal and / or channel composites may additionally or alternatively include uplink physical signals and channels. Two such examples, which may be additionally or alternatively included in the set, are depicted in Figure 7.

[0099] In the example composite labeled (g) in Figure 7, a downlink synchronization signal is first followed by a SRS transmission from the UE, and then by a downlink transmission of a physical control channel dynamically scheduling a downlink data transmission channel (a PDSCH in this example). In the composite (g), the SRS could be replaced with a signal suitable for timing estimation, e.g. a PRACH signal, to not only acquire directional information but also uplink timing. This signal combination may e.g. be used to quickly start transmitting with detailed channel state information from a new TRP, cell or carrier. P111026W001 16

[0100] In the example composite labeled (h) in Figure 7, the downlink synchronization signal is first followed by a downlink CSI-RS and then by an uplink physical data channel transmission (here denoted PUSCH). This signal combination may e.g., be used to quickly start transmitting uplink data with detailed channel state information available in the transmitting UE.

[0101] Figure 8 illustrates one example of an indexable table (e.g., using 3 bits) of the predefined set of signal and / or channel composites illustrated in the examples of Figures 6 and 7. In this example, there are eight entries (i.e., eight signal and / or channel composites) in the table (i.e., in the set). Therefore, activation of one of the set of signal and / or channel composites may be signaled using a 3-bit indicator that indicates an entry in the table. In some embodiments, these additional bits (e.g., 3 bits in the example using the table of Figure 8) are provided either:

[0102] • explicitly or implicitly in a MIB contained in a PBCH that is one of the parts of the SSB, or

[0103] • in a DCI scheduling a transmission of a composite synchronization signal set (e.g., on another carrier).

[0104] Figure 9 illustrates the operation of a UE 512 and a RAN node 900 (e.g., a base station 502) in accordance with embodiments of the present disclosure. Optional steps or functions are represented in Figure 9 by dashed lines or boxes. As illustrated, the UE 512 obtains information that configures the UE 512 with a set of signal and / or channel composites (step 902). Each signal and / or channel composite in the set of signal and / or channel composites includes a synchronization signal component (e.g., a PSS, an SSS, both a PSS and an SSS, or an SSB containing a PSS, SSS, and PBCH). Note that different composites in the set may include different types of synchronization signal components (e.g., different SSB types). In addition, at least one signal and / or channel composite in the set further includes one or more additional signals (e.g., one or more DL reference signals and / or one or more UL reference signals) and / or one or more additional channels (e.g., one or more DL channels and / or one or more UL channels).

[0105] In one embodiment, the information that configures the UE 512 with the set of signal and / or channel composites is at least partly predefined, e.g., a standard (e.g., in one or more 3GPP specification).

[0106] In another embodiment, the information that configures the UE 512 with the set of signal and / or channel composites is signaled to the UE 512 from the RAN node 900 P111026W001 17

[0107] (see step 902A). More specifically, the RAN node 900 determines a configuration of the set of signal and / or channel composites, e.g., based on a detected use case or scenario (see examples in Figure 8) (step 901) and transmits, to the UE 512, the information (or at least part of the information) that configures the UE 512 with the set of signal and / or channel composites (step 902A). In one embodiment, the information signaled to the UE 512 in step 902A is at least partly contained in an RRC configuration while the UE 512 is in a connected mode state and / or at least partly contained in a message in a broadcasted system information block (e.g., MIB). In one embodiment, a part of the information that configures the UE 512 with the set of signal and / or channel composites is predefined, e.g., by a standard (e.g., one or more 3GPP specifications) rather than signaled to the UE 512 in step 902A.

[0108] The UE 908 obtains in indication (e.g., an index) of one of the set of signal and / or channel composites (step 908). In other words, the UE 908 obtains an indication of one of the set of signal and / or channel composites to be activated. More specifically, in one embodiment, the RAN node 900 determines a need for transmission of an on-demand synchronization signal component (e.g., an on-demand SSB) (step 904), selects one of the set of signal and / or channel composites configured for the UE 512 (step 906), and transmits, to the UE, the indication (e.g., index) of the selected signal and / or channel composite (step 908A). The determination in step 904 may, in some embodiments, be performed by detecting an event (e.g., a mobility event) for which transmission of an on-demand synchronization signal component (e.g., M-SSB) is needed (see, e.g., the example use cases of Figure 8). Then, in step 906, the RAN node 900 selects one of the signal and / or channel composites from the set that is associated to (e.g., mapped to) the detected event.

[0109] In one embodiment, the indication of step 908 is obtained by the UE 512 via any one of the following options:

[0110] • an information field contained in a physical broadcast channel transmitted (in step 908A) in direct association with the synchronization signal component (i.e., in a MIB);

[0111] • a DCI field contained in a PDCCH, enhanced PDCCH (ePDCCH), or the like, e.g., in step 908A;

[0112] • MAC CE field transmitted in step 908A;

[0113] • an RRC message transmitted in step 908A; P111026W001 18

[0114] • by reception of a predefined SSB type on a predefined frequency and time resource (e.g., a D-SSB on a secondary carrier); or

[0115] • by a UE blind detection procedure (e.g., hypothesis testing, e.g. by using different DMRS sequences or CRC check).

[0116] Other options are also possible.

[0117] The UE 512 then operates (e.g., transmits and / or receives) in accordance with the indicated one of the set of signal and / or channel composites (step 910). In other words, the UE 512 receives and / or transits the signals and / or channels as defined by the indicated one of the set of signal and / or channel composites. In a similar manner, the RAN node 900 may also operate (e.g., transmit and / or receive) in accordance with the indicated one of the set of signal and / or channel composites (step 912). In other words, the RAN node 900 receives and / or transits the signals and / or channels as defined by the indicated one of the set of signal and / or channel composites.

[0118] Figure 10 is a schematic block diagram of a RAN node 1000 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The RAN node 1000 is one example of the RAN node 900. As illustrated, the RAN node 1000 includes a control system 1002 that includes one or more processors 1004 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and / or the like), memory 1006, and a network interface 1008. The one or more processors 1004 are also referred to herein as processing circuitry. In addition, the RAN node 1000 may include one or more radio units 1010 that each includes one or more transmitters 1012 and one or more receivers 1014 coupled to one or more antennas 1016. The radio units 1010 may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) 1010 is external to the control system 1002 and connected to the control system 1002 via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) 1010 and potentially the antenna(s) 1016 are integrated together with the control system 1002. The one or more processors 1004 operate to provide one or more functions of a RAN node 1000 as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 1006 and executed by the one or more processors 1004.

[0119] Figure 11 is a schematic block diagram that illustrates a virtualized embodiment of the RAN node 1000 according to some embodiments of the present disclosure. This P111026W001 19 discussion is equally applicable to other types of network nodes. Further, other types of network nodes may have similar virtualized architectures. Again, optional features are represented by dashed boxes.

[0120] As used herein, a "virtualized" radio access node is an implementation of the RAN node 1000 in which at least a portion of the functionality of the RAN node 1000 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the RAN node 1000 may include the control system 1002 and / or the one or more radio units 1010, as described above. The control system 1002 may be connected to the radio unit(s) 1010 via, for example, an optical cable or the like. The RAN node 1000 includes one or more processing nodes 1100 coupled to or included as part of a network(s) 1102. If present, the control system 1002 or the radio unit(s) are connected to the processing node(s) 1100 via the network 1102. Each processing node 1100 includes one or more processors 1104 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 1106, and a network interface 1108.

[0121] In this example, functions 1110 of the RAN node 1000 described herein are implemented at the one or more processing nodes 1100 or distributed across the one or more processing nodes 1100 and the control system 1002 and / or the radio unit(s) 1010 in any desired manner. In some particular embodiments, some or all of the functions 1110 of the RAN node 1000 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1100. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 1100 and the control system 1002 is used in order to carry out at least some of the desired functions 1110. Notably, in some embodiments, the control system 1002 may not be included, in which case the radio unit(s) 1010 communicate directly with the processing node(s) 1100 via an appropriate network interface(s).

[0122] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of RAN node 1000 or a node (e.g., a processing node 1100) implementing one or more of the functions 1110 of the RAN node 1000 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is P111026W001 20 provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0123] Figure 12 is a schematic block diagram of the RAN node 1000 according to some other embodiments of the present disclosure. The RAN node 1000 includes one or more modules 1200, each of which is implemented in software. The module(s) 1200 provide the functionality of the RAN node 1000 described herein. This discussion is equally applicable to the processing node 1100 of Figure 11 where the modules 1200 may be implemented at one of the processing nodes 1100 or distributed across multiple processing nodes 1100 and / or distributed across the processing node(s) 1100 and the control system 1002.

[0124] Figure 13 is a schematic block diagram of a UE 1300 according to some embodiments of the present disclosure. The UE 1300 is one example embodiment of the UE 512. As illustrated, the UE 1300 includes one or more processors 1302 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 1304, and one or more transceivers 1306 each including one or more transmitters 1308 and one or more receivers 1310 coupled to one or more antennas 1312. The transceiver(s) 1306 includes radio-front end circuitry connected to the antenna(s) 1312 that is configured to condition signals communicated between the antenna(s) 1312 and the processor(s) 1302, as will be appreciated by on of ordinary skill in the art. The processors 1302 are also referred to herein as processing circuitry. The transceivers 1306 are also referred to herein as radio circuitry. In some embodiments, the functionality of the UE 1300 described above may be fully or partially implemented in software that is, e.g., stored in the memory 1304 and executed by the processor(s) 1302. Note that the UE 1300 may include additional components not illustrated in Figure 13 such as, e.g., one or more user interface components (e.g., an input / output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and / or the like and / or any other components for allowing input of information into the UE 1300 and / or allowing output of information from the UE 1300), a power supply (e.g., a battery and associated power circuitry), etc.

[0125] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the UE 1300 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer P111026W001 21 program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0126] Figure 14 is a schematic block diagram of the UE 1300 according to some other embodiments of the present disclosure. The UE 1300 includes one or more modules 1400, each of which is implemented in software. The module(s) 1400 provide the functionality of the UE 1300 described herein.

[0127] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0128] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0129] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

P111026W001 22Claims1. A method performed by a User Equipment, UE, the method comprising: obtaining (902) information that configures the UE with a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel; obtaining (908), from a Radio Access Network, RAN, node, an indication of one of the set of signal and / or channel composites; and operating (910) in accordance with the one of the set of signal and / or channel composites.

2. The method of claim 1, for each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite is a synchronization signal block, SSB, that contains a primary synchronization signal, PSS, a secondary synchronization signal, SSS, and a physical broadcast channel, PBCH.

3. The method of claim 1, for each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite contains a primary synchronization signal, PSS, and a secondary synchronization signal, SSS.

4. The method of any of claims 1 to 3, wherein the at least one additional reference signal or channel comprises: (a) a downlink reference signal, (b) an uplink reference signal, (c) a downlink channel, (d) an uplink channel, or (e) a combination of any two or more of (a)-(d).

5. The method of any of claims 1 to 4, wherein the operating (910) in accordance with the one of the set of signal and / or channel composites comprises receiving (910) the synchronization signal component comprised in the one of the set of signal and / or channel composites.P111026W001 236. The method of claim 5, wherein the one of the set of signal and / or channel composites further comprises a downlink channel, and operating (910) in accordance with the one of the set of signal and / or channel composites comprise receiving (910) the downlink channel comprised in the one of the set of signal and / or channel composites.

7. The method of claim 5, wherein the one of the set of signal and / or channel composites further comprises a downlink reference signal, and operating (910) in accordance with the one of the set of signal and / or channel composites comprise receiving (910) the downlink reference signal comprised in the one of the set of signal and / or channel composites.

8. The method of any of claims 5 to 7, wherein the one of the set of signal and / or channel composites further comprises an uplink reference signal, and operating (910) in accordance with the one of the set of signal and / or channel composites comprise transmitting (910) the uplink reference signal comprised in the one of the set of signal and / or channel composites.

9. The method of any of claims 1 or 8, wherein obtaining (902) the information that configures the UE with the set of signal and / or channel composites comprises receiving (902) the information that configures the UE with the set of signal and / or channel composites from a RAN node.

10. The method of claim 9, wherein receiving (902) the information that configures the UE with the set of signal and / or channel composites from the RAN node comprises receiving at least part of the information via a Radio Resource Control, RRC, configuration while in a connected mode state.

11. The method of claim 9 or 10, wherein receiving (902) the information that configures the UE with the set of signal and / or channel composites from the RAN node comprises receiving at least part of the information via a message in a broadcasted system information block.P111026W001 2412. The method of any of claims 1 to 11, wherein at least part of the information that configures the UE with the set of signal and / or channel composites is predefined via a standard specification.

13. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication from the RAN node via an information field contained in a physical broadcast channel transmitted in direct association with the synchronization signal component.

14. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication from the RAN node via an information field contained in a master information block.

15. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication from the RAN node in a downlink control information, DCI, field contained in a physical downlink control channel.

16. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication from the RAN node in medium access control, MAC, control element, CE, field.

17. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication from the RAN node in a radio resource control, RRC, message.

18. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication via reception of a predefined synchronization signal block, SSB, type on a predefined frequency and time resource.P111026W001 2519. The method of any of claims 1 to 12, wherein obtaining (908) the indication of one of the set of signal and / or channel composites comprises receiving (908) the indication via a UE blind detection procedure.

20. A User Equipment, UE, adapted to: obtain (902) information that configures the UE with a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel; obtain (908), from a Radio Access Network, RAN, node, an indication of one of the set of signal and / or channel composites; and operate (910) in accordance with the one of the set of signal and / or channel composites.

21. The UE of claim 20, further adapted to perform the method of any of claims 2 to 19.

22. A User Equipment, UE, comprising: a transmitter (1308); a receiver (1310); and processing circuitry (1302) associated with the transmitter (1308) and the receiver (1310), the processing circuitry (1302) configured to cause the UE to: obtain (902) information that configures the UE with a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel;P111026W001 26 obtain (908), from a Radio Access Network, RAN, node, an indication of one of the set of signal and / or channel composites; and operate (910) in accordance with the one of the set of signal and / or channel composites.

23. The UE of claim 22, wherein the processing circuitry is further configured to cause the UE to perform the method of any of claims 2 to 19.

24. A method performed by a Radio Access Network, RAN, node for a RAN of a cellular communications system, the method comprising: transmitting (908A) to a User Equipment, UE, an indication of one of a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel; and operating (912) in accordance with the one of the set of signal and / or channel composites.

25. The method of claim 24, for each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite is a synchronization signal block, SSB, that contains a primary synchronization signal, PSS, a secondary synchronization signal, SSS, and a physical broadcast channel, PBCH.

26. The method of claim 24, for each composite of the set of signal and / or channel composites, the synchronization signal component comprised in the composite contains a primary synchronization signal, PSS, and a secondary synchronization signal, SSS.

27. The method of any of claims 24 to 26, wherein the at least one additional reference signal or channel comprises: (a) a downlink reference signal, (b) an uplink reference signal, (c) a downlink channel, (d) an uplink channel, or (e) a combination of any two or more of (a)-(d).P111026W001 2728. The method of any of claims 24 to 27, wherein the operating (912) in accordance with the one of the set of signal and / or channel composites comprises transmitting (912) the synchronization signal component comprised in the one of the set of signal and / or channel composites.

29. The method of claim 28, wherein the one of the set of signal and / or channel composites further comprises a downlink channel, and operating (912) in accordance with the one of the set of signal and / or channel composites comprises transmitting (910) the downlink channel comprised in the one of the set of signal and / or channel composites.

30. The method of claim 28, wherein the one of the set of signal and / or channel composites further comprises a downlink reference signal, and operating (912) in accordance with the one of the set of signal and / or channel composites comprises transmitting (912) the downlink reference signal comprised in the one of the set of signal and / or channel composites.

31. The method of any of claims 24 to 30, wherein the one of the set of signal and / or channel composites further comprises an uplink reference signal, and operating (912) in accordance with the one of the set of signal and / or channel composites comprises receiving (912) the uplink reference signal comprised in the one of the set of signal and / or channel composites.

32. The method of any of claims 24 to 31, further comprising, prior to transmitting (908A) the indication, transmitting (902A), to the UE, information that configures the UE with the set of signal and / or channel composites.

33. The method of claim 32, wherein transmitting (902A) the information that configures the UE with the set of signal and / or channel composites comprises transmitting (902A) at least part of the information via a Radio Resource Control, RRC, configuration while in a connected mode state.P111026W001 2834. The method of claim 32 or 33, wherein transmitting (902A) the information that configures the UE with the set of signal and / or channel composites comprises transmitting (902A) at least part of the information via a message in a broadcasted system information block.

35. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication via an information field contained in a physical broadcast channel transmitted in direct association with the synchronization signal component.

36. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication via an information field contained in a master information block.

37. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication from the RAN node in a downlink control information, DCI, field contained in a physical downlink control channel.

38. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication from the RAN node in medium access control, MAC, control element, CE, field.

39. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication from the RAN node in a radio resource control, RRC, message.

40. The method of any of claims 24 to 34, wherein transmitting (908A) the indication of the one of the set of signal and / or channel composites comprises transmitting (908A) the indication via transmission of a predefined synchronization signal block, SSB, type on a predefined frequency and time resource.P111026W001 2941. The method of any of claims 24 to 31, further comprising, prior to transmitting (908A) the indication: determining (904) a need for transmission of an on-demand synchronization signal component; and in response to determining (904) the need, selecting the one of the set of signal and / or channel composites.

42. The method of any of claims 24 to 31, further comprising, prior to transmitting (908A) the indication: detecting (904) an event indicative of a need for transmission of an on-demand synchronization signal component; and in response to detecting (904) the event, selecting the one of the set of signal and / or channel composites, the selected one of the set of signal and / or channel composites being associated to the detected event.

43. A Radio Access Network, RAN, node for a RAN of a cellular communications system, the RAN node adapted to: transmit (908A) to a User Equipment, UE, an indication of one of a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel; and operate (912) in accordance with the one of the set of signal and / or channel composites.

44. The RAN node of claim 43, further adapted to perform the method of any of claims 25 to 42.

45. A Radio Access Network, RAN, node for a RAN of a cellular communications system, the RAN node comprising processing circuitry configured to cause the RAN node to:P111026W001 30 transmit (908A) to a User Equipment, UE, an indication of one of a set of signal and / or channel composites, wherein: each composite of the set of signal and / or channel composites comprises a synchronization signal component; and at least one composite of the set of signal and / or channel composites comprises both a synchronization signal component and at least one additional reference signal or channel; and operate (912) in accordance with the one of the set of signal and / or channel composites.

46. The RAN node of claim 45, wherein the processing circuitry is further configured to cause the RAN node to perform the method of any of claims 25 to 42.

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