WO2023131743A1 - A method, and apparatus for inter-cell beam management - Google Patents

Abstract

There is provided an apparatus, a method and a computer program product. In accordance with an embodiment the method comprises obtaining, by a user device (110), one or more synchronization signal block identifiers, wherein the one or more synchronization signal block identifiers are used for physical downlink control channel monitoring for the serving cell; and reporting, by the user device, the one or more synchronization signal block identifiers to at least one of the serving cell and a non-serving cell.

Description

A METHOD, AND APPARATUS FOR INTER-CELL BEAM MANAGEMENT

TECHNICAL FIELD

The present invention relates to a method and apparatus for measurement adjustment in low mobility of a user device.

BACKGROUND

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

5G-NR (5^th generation New Radio) is a new radio access technology which has been developed by the 3^rd generation partnership project (3GPP) for the 5^th generation mobile networks. 5G-NR has been specified within 3GPP to be able to coexist with 4G-LTE (Long Term Evolution) within the same spectrum.

In 5G systems a base station may have a MIMO (Multiple In Multiple Out) antenna array comprising dozens of individual antenna elements. Signals to and from those antenna elements can be controlled e.g. by signal-processing algorithms so that a good transmission route may be utilized through air to each user device. Then the base stations can send individual data packets in many different directions (with different beams). Beamforming allows many users and antennas on such MIMO array to exchange much more information at once.

For millimeter waves used in 5G networks, beamforming is primarily used to address a different set of problems: cellular signals are easily blocked by objects and tend to weaken over long distances, wherein beamforming may help by focusing a signal in a concentrated beam that points only in the direction of a user device rather than broadcasting in many directions at once. This approach may increase the probability that the signals arrive intact and may also reduce interference for everyone else. Multi -beam/beam management enhancements involves inter-cell beam management, which means that a user device (may also call user equipment, UE) may be receiving and transmitting signals and channels associated to physical cell ID (PCI) different than the PCI of the serving cell. The UE may be monitoring a Physical Downlink Control Channel (PDCCH) both from the serving cell and from a cell associated with a PCI different than the PCI of the serving cell.

Some further enhancements can be identified for NR MIMO (feMIMO). Enhancements may relate to multi-beam operation, mainly targeting the higher frequency range FR2 while which may also be applicable to the lower frequency range FR1 of NR. For inter-cell beam management, a UE can transmit to or receive from only a single cell (i.e. serving cell does not change when beam selection is done).

Some UEs with limited capability may only support one active transmission coordination indicator (TCI) state i.e., only one TCI state can be active for the UE. It would cause some problems for the UEs which support only one TCI state is active.

SUMMARY

Some embodiments provide a method and apparatus for reporting the one or more identifiers of a synchronization signal block to the serving cell and/or non-serving cell.

According to an embodiment, UE determines the SSB of the serving cell based on which the UE performs TypeO-PDCCH monitoring and/or Type 1 -PDCCH monitoring, and reports the determined SSB to serving cell and/or non-serving cell. Based on this information, the serving cell and/or non-serving cell knows on which resources should be used for PDCCH scheduling. Based on above information, the UE will switch between serving cell and non-serving cell which may avoid PDCCH missing due to ambiguity between the gNB and the UE.

More specifically, the one or more SSB identifiers is used to indicate the PDCCH monitoring, e.g. Type 1 -PDCCH and/or Type 1 -PDCCH, for data channel when the UE switches between the serving cell and non-serving cell. The reports of one or more SSB identifiers to the non-serving cell may go through the serving cell. The report of one or more SSB identifiers is at least send to the non-serving cell. In some embodiments, the UE is configured a reporting mode based on which the UE reports to the gNB the SSB of the serving cell based on which the UE performs TypeO-PDCCH monitoring and/or Typel-PDCCH monitoring. In this case one option is that UE's Ll-RSRP reporting format is such that it always has one entry for reporting of the SSB of the serving cell the UE assumes for the CSS monitoring. Upon reception of the SSB the gNB can determine PDCCH monitoring occasions, e.g. TypeO-PDCCH monitoring occasions, when the UE performs CSS monitoring in serving cell. In one option UE can be configured to indicate N SSBs (N=l,2,3, and it may be configurable by network) that it uses for CSS monitoring.

In addition, the UE may indicate the gNB, e.g. as a capability information, that how much time is needed when the UE cannot be scheduled before and after the monitoring occasions of TypeO- PDCCH and/or Typel-PDCCH in the serving cell. Hence, the gNB may utilize this information when e.g. sending scheduling information.

In accordance with an embodiment, the UE can assume that it does not need to monitor dedicated PDCCH from non-serving cell during the time when the UE is monitoring TypeO-PDCCH and/or Typel-PDCCH in the serving cell on the occasions associated to the reported SSB. In addition, the no-monitoring period may include the additional time margin before and after monitoring occasions of the serving cell. The time margin may be configured by the network and being equal to or greater than UE's provided capability value. Hence, this may save some workload of the UE.

The network may send acknowledgement or confirmation to UE's report.

In one embodiment, when the UE has been configured with at least one SSB associated with the serving cell (PCI) for Ll-RSRP measurements, it selects the SSB for CSS monitoring out of the set of configured SSB (as a QCL source for CSS). The UE may indicate the selected SSB in a Ll- RSRP report/beam report that is configured for mixed beam reporting for serving cell PCI and at least one other PCI (e.g. the one where UE monitors USS) or in a specific reporting instance/reporting configuration. In one embodiment, the reporting configuration for indicating the SSB(s) for CSS monitoring assumes that all the SSBs in a cell are considered to be configured i.e. the UE can refer to SSBs using the SSB index (in the beam report).

In one embodiment, the network, upon receiving the indicated SSB for CSS monitoring, can assume that the UE is available for scheduling when the CSS of the serving cell overlaps with USS of PCI different than the serving cell on occasions that do not correspond to the indicated SSB. For example, when an SSB is not the QCL source for the PDCCH scheduled on CSS, the UE is assumed to be available for scheduling. This may help the gNB to perform the scheduling operation at a correct moment.

In one embodiment, the UE, upon indicating an SSB for CSS monitoring, it is assumed to be available for scheduling when the CSS of the serving cell overlaps with the USS of the PCI different than the serving cell on occasions that do not correspond to the indicated SSB (i.e. SSB is assumed to be the QCL source for the PDCCH DMRS for CSS and UE monitors only CSS on specific SSB / SSBs).

Some embodiments are implemented in the context of the 5G communication systems and relate to a UE implementation of mechanisms for reporting the one or more identifiers of a synchronization signal block to the serving cell and/or non-serving cell.

According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure.

According to a first aspect there is provided an apparatus comprising at least one processor, and a transceiver, wherein the at least one processor is configured to: obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used for physical downlink control channel, PDCCH, monitoring for a serving cell; and wherein the transceiver is configured to: report the one or more SSB identifiers to the serving cell and/ir a non-serving cell. According to a second aspect there is provided a method comprising: obtaining one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used for physical downlink control channel, PDCCH, monitoring for a serving cell; and reporting the one or more SSB identifiers to the serving cell and/or a non-serving cell.

According to a third aspect there is provided an apparatus comprising at least one processor; and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following: obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more synchronization signal block identifiers are used for physical downlink control channel, PDCCH, monitoring for a serving cell; and report the one or more SSB identifiers to the serving cell and/or a non-serving cell.

According to a fourth aspect there is provided a computer program comprising computer readable program code which, when executed by at least one processor; cause the apparatus to perform at least the following: obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used for physical downlink control channel monitoring for a serving cell; and report the one or more SSB identifiers to the serving cell and/or a non-serving cell.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

Fig. 1 shows a block diagram of one possible and non-limiting example in which the examples may be practiced;

Fig. 2 illustrates a part of a wireless network having several base stations and an exemplary user device; Fig. 3 illustrates an example of TCI state switching for PDCCH reception, in accordance with an approach;

Fig. 4 illustrates several downlink beam management procedures, in accordance with an approach; Fig. 5 illustrates a unified TCI framework for downlink signals and channels, in accordance with an approach;

Fig. 6 illustrates a procedure for generating PDCCH from DCI, in accordance with an approach;

Fig. 7a shows an exemplary flow chart, in accordance with an embodiment;

Fig. 7b shows an exemplary signalling chart, in accordance with an embodiment;

Fig. 8 shows a part of an exemplifying wireless communications access network in accordance with at least some embodiments;

Fig. 9 shows a block diagram of an apparatus in accordance with at least some embodiments; and

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

It should be noted here that in this specification, the term ‘base station’ refers to a logical element containing logical communication system layers (e.g. LI, L2, L3). The base stations of different RATs may be implemented in the same hardware or at separate hardware. It should also be mentioned that although the expressions “each base station” and “each mobile station” or “each user device” may be used, these terms need not mean every existing base station, mobile station or user device but base stations, mobile stations or user device in a certain area or set. For example, each base station may mean all base stations within a certain geographical area or all base stations of an operator of a wireless communication network or a sub-set of base stations of an operator of a wireless communication network.

In a case the TCI state is not defined or configured and/or activated for the UE in the serving cell it is not clear for the UE which QCL assumption/TCI state to apply for monitoring PDCCH associated with a user specific search space (USS) from PCI#1 (e.g., the inter-cell BM cell/cell with different PCI) and for monitoring PDCCH associated with a common search space (CSS) on PCI#0 (e.g., the serving cell) when the monitoring occasions are overlapping or are close in time. When the UE supports only one active TCI state, the network may not be able to configure the UE to monitor specific downlink reference signal (DL RS) for CSS reception and this creates a problem e.g. for the scheduling on USS.

Similarly, the UE may have configuration of CORESET type C with USS/CSS and the beam indication only applies for the USS part and UE needs to monitor CSS part of the CORESET on the serving cell.

If there is an ambiguity of TCI state/QCL assumption for the UE, it may not be able to determine the proper assumptions for Ll-RSRP measurements e.g. whether it can assume that RS overlaps or not with the PDCCH reception on the serving cell (scheduled on CSS).

Furthermore, in case the network is not able to configure the UE with a TCI state that would be used for CSS monitoring on the serving cell, the network is not aware based on which DL RS (e.g. a Synchronization Signal Block (SSB) when the UE monitors CSS on TypeO-PDCCH) the UE monitors for CSS reception and thus on which monitoring occasions. That may limit the scheduling flexibility of the PCI different than the serving cell, e.g. it would need to assume a scheduling gap to accommodate all the transmitted SSBs. In FR2 and with 120 kHz subcarrier spacing the time duration of all the SSBs (max 64) is almost 5 ms meaning relatively long gap in scheduling impacting severely onto user experience.

Hence, a solution would be needed to solve ambiguity between the gNB and the UE in case the UE supports only one active TCI state at a time when UE is configured inter-cell beam management.

Fig. 1 shows a block diagram of one possible and non-limiting example in which the examples may be practiced. A user device 110, radio access network (RAN) node 170, and network element(s) 190 are illustrated. The user device 110 may also be called user equipment (UE) in the present application. In the example of FIG. 1, the user device 110 is in wireless communication with a wireless network 100. A user device is a wireless device that can access the wireless network 100. The user device 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fibre optics or other optical communication equipment, and the like.

The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The user device 110 includes a module 140, which may be implemented in a number of ways. The module 140 may be implemented in hardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140- 1 may also be implemented as an integrated circuit or through other hardware such as a programmable gate array.

In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user device 110 to perform one or more of the operations as described herein. The user device 110 communicates with RAN node 170 via a wireless link 111. The modules 140-1 and 140-2 may be configured to implement the functionality of the user device as described herein.

The RAN node 170 in this example is a base station that provides access by wireless devices such as the user device 110 to the wireless network 100. Thus, the RAN node 170 (and the base station) may also be called as an access point of a wireless communication network).

The RAN node 170 may be, for example, a base station for 5G, also called New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as either a gNB or an ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE and connected via the NG interface to a 5GC (such as, for example, the network element(s) 190). The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE and connected via the NG interface to the 5GC. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs), of which DU 195 is shown. Note that the DU 195 may include or be coupled to and control a radio unit (RU). The gNB-CU 196 is a logical node hosting radio resource control (RRC), SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU 196 terminates the Fl interface connected with the gNB-DU 195. The Fl interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB- DU 195 is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU 196. One gNB-CU 196 supports one or multiple cells. One cell is supported by only one gNB-DU 195. The gNB-DU 195 terminates the Fl interface 198 connected with the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195.

The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution), or any other suitable base station or node.

The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor(s) 152, memory(ies) 155, and network interfaces 161. Note that the DU 195 may also contain its own memory/memories and processor(s), and/or other hardware, but these are not shown.

The RAN node 170 includes a module 150, comprising one of or both parts 150-1 and/or 150-2, which may be implemented in a number of ways. The module 150 may be implemented in hardware as module 150-1, such as being implemented as part of the one or more processors 152. The module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152.

For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195. The modules 150-1 and 150-2 may be configured to implement the functionality of the base station described herein. Such functionality of the base station may include a location management function (LMF) implemented based on functionality of the LMF described herein. Such LMF may also be implemented within the RAN node 170 as a location management component (LMC).

The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like.

For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from the RRH/DU 195, and the one or more buses 157 could be implemented in part as, for example, fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU), gNB-CU) of the RAN node 170 to the RRH/DU 195. Reference 198 also indicates those suitable network link(s). It is noted that description herein indicates that "cells" perform functions, but it should be clear that equipment which forms the cell may perform the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For example, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360 degree area so that the single base station's coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So, if there are three 120-degree cells per carrier and two carriers, then the base station has a total of 6 cells.

The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and/or a data communications network (e.g., the Internet). Such core network functionality for 5G may include location management functions (LMF(s)) and/or access and mobility management function(s) (AMF(S)) and/or user plane functions (UPF(s)) and/or session management function(s) (SMF(s)). Such core network functionality for LTE may include MME (Mobility Management Entity)/SGW (Serving Gateway) functionality.

These are merely example functions that may be supported by the network element(s) 190 and note that both 5G and LTE functions might be supported. The RAN node 170 is coupled via a link 131 to the network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the network element 190 to perform one or more operations such as functionality of an LMF as described herein.

In some examples, a single LMF could serve a large region covered by hundreds of base stations. The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization.

Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and 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 computer readable memories 125, 155, and 171 may be means for performing storage functions.

The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, network element(s) 190, and other functions as described herein.

In general, the various embodiments of the user device 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions. Module 150-1 and/or module 150-2 may implement the functionalities and signaling of the gNB or radio node as herein described. Computer program code 173 may implement the functionalities and signaling of the AMF or network element as herein described.

Fig. 2 illustrates a part of a wireless network 100 having several base stations 170 and an exemplary user device 110. In Fig. 2 it is assumed that the base station marked as S-BS is the serving base station, when the user device is in connected mode, and the base station where the user device is camped on when not in connected mode. Some of the neighbouring base stations are labelled as N-BS in Fig. 2. In practical situations the serving base station and the camped on base station may change e.g. when the user device is moving, or if the signal strength from different base stations changes (e.g. signals from a neighbouring base station N-BS becomes stronger than signals from the currently serving base station.

In accordance with an example, the base station (a.k.a. an access point), may have one or more transmission-reception points (TRP) which transmit transmission beams to be received by user device(s).

A base station may have a spatial beam codebook which includes information of beams available by a base station.

The UE can be configured to receive UE specific channels/signals on a cell with different PCI than the serving cell. In practise, the UE receives indication for at least one TCI State for a CORESET where the TCI State further indicates DL RS associated with a PCI different than the serving cell (e.g. PCIl).

Since the common channels are monitored on the serving cell (e.g., PCI0) even when the UE dedicated channels are configured to be monitored on another cell (a cell with different PCI, assisting cell, inter cell BM cell, additional cell or the like), it is not clear how the UE determines the monitoring of common channels on the serving cell. In particular, what is the TCI State/QCL assumption for PDCCH reception in CSS when UE is indicated with a TCI state associated with PCI other than serving cell. At least three types of CORESETs may be defined:

CORESET type A: a CORESET associated with USS only CORESET type B: a CORESET associated with CSS only CORESET type C: a CORESET associated with both USS and CSS

In accordance with an approach, these three coreset types are as follows:

The 'CORESET A' is a configuration resource set other than CORESET 0 associated with only UE-dedicated reception on PDCCH in a CC, comprising CORESETs in association with USS and/or CSS Type 3.

The 'CORESET B' is a configuration resource set other than CORESET 0 associated with only non-UE-dedicated reception on PDCCH in a CC, comprising CORESETs in association with CSS or CSS other than Type 3.

The 'CORESET C' is a configuration resource set other than CORESET 0 associated with both UE-dedicated and non-UE-dedicated reception on PDCCH in a CC.

For the TCI state indication, support per CORESET determination may be as follows:

For any PDCCH reception on a 'CORESET A' and the respective PDSCH reception, the UE always applies the indicated TCI state.

For any PDCCH reception on a 'CORESET B' and the respective PDSCH reception, whether or not the UE to apply the indicated TCI state associated with the serving cell is determined per CORESET by an RRC.

In the following, some beam management principles are described according to an approach. A beam is characterized by a certain reference signal. A beam may also be defined as a spatial filter. From UE perspective, a certain reference signal may be a source RS for the RX beam determination in downlink in a way that the UE can apply the same RX beam to receive some target signal like DMRS of PDCCH and PDCCH as it used for the reception of certain source signal (QCL source, QCL-TypeD RS) like CSI-RS. TCI state activated for CORESET (for PDCCH reception) provides source reference signals to receive PDCCH DMRS and PDCCH. A beam is transmitted or received to/from a spatial direction, and a beam is formed by using a set of antennas, which is controlled by a controller (for example a baseband controller).

The shape and direction of a beam may be determined by what kind of function is used. This kind of special function may be called as a beamforming function or a mapping function or a spatial filter. When the UE or gNB applies the same spatial filter, it means that it forms the same beam, i.e, a radiation pattern of the antenna has the same direction, the same shape, and the same power of the beam.

A large number of antennas may be utilized by a base station and the UE NR to obtain highly directional beamformed transmission and reception between the base station and the UE. Hybrid beamforming is a combination of analog beamforming that applies different phase shifters and/or amplitude weights on each antenna panel and digital beamforming that applies different digital precoders across panels.

To support multi -beam-based operation for the PDCCH, NR supports a higher-layer configuration for beamforming (transmission configuration indication (TCI) state configuration) per CORESET. When a UE monitors a SS set associated with a CORESET, the UE can receive the PDCCH in the CORESET based on the TCI state configuration configured for the CORESET.

Beam management comprises a set of procedures and functionalities that enable, maintain and refine the transmit and receive beam alignment between the transmitter and the receiver(s). A beam pair link established between the transmitter and the receiver comprises a transmit beam and receive beam pair. The beam pair link between gNB and UE may be the same or different in downlink and uplink. In DL gNB provides UE with a quasi-co-location (QCL)-TypeD RS based on which the UE can set its receive beam and a spatial relation info in UL, based on which the UE can further set its transmit beam.

The quasi collocation of two antenna ports means that the channel conditions for the symbols transmitted from those antenna ports are similar. Depending on the set of properties for the channel conditions 3GPP TS 38.214 defines the following QCL-types: QCL-TypeA, QCL-TypeB, QCL- TypeC, QCL-TypeD. In this IR we particularly focus on the QCL-TypeD where the spatial Rx parameter is employed to define the channel conditions and is used to support beamforming.

Strictly speaking, QCL defines the relation between two reference signals at the UE receiver. In practice, the gNB may only guarantee that the properties of two reference signals are similar if the two reference signals are transmitted from the same transmission and reception point (TRP). NR considers in general that the transmission of any reference signal from any TRP.

QCL-TypeD RS can be SSB or CSLRS. In beam indication for the target signal to be received (e.g. DMRS of PDSCH, DMRS of PDCCH, CSI-RS) the UE is provided a TCI state (container) that comprises an indication of the QCL-TypeD RS. The UE applies the same reception beam (RX beam) to receive target signal, as it used to receive the given QCL-TypeD RS (SSB or CSI-RS resource) in the TCI state. In other words, the UE applies the same spatial filter in the receiver 132 in both cases.

The UE can be configured with up to 64 or 128 (if UE capability allows) TCI states.

In accordance with an approach, TCI State container may be as follows:

TCI-State ::= SEQUENCE { tci-Stateld TCLStateld, qcl-Typel QCL-Info, qcl-Type2 QCL-Info, OPTIONAL, - Need R

QCL-Info ::= SEQUENCE { cell ServCelllndex OPTIONAL, - Need R bwb-Id BWP-Id OPTIONAL, - Cond CSI-RS-Indicated referenceSignal CHOICE { csi-rs NZP-CSI-RS-Resourceld, ssb SSB-Index

} qcl-Type ENUMERATED {typeA, typeB, typeC, typed}, In the DL the UE may be provided a source RS to determine a receive spatial filter. It can be an SSB or CSI-RS. In the UL, the UE may be provided, in addition to SSB and CSLRS, one or more sounding RS (SRS) as spatial source RSs for the UE to determine a transmit spatial filter for some target signal or channel like SRS, PUCCH and PUSCH. In case of SSB or CSI-RS the UE uses the RX beam to receive or sweep the SSB or CSI-RS resource as spatial relation for the TX beam of the UE for transmitting a target signal (e.g. PUSCH, PUCCH, SRS).

For UL transmission, the UE may use as the TX beam to transmit target signal correlated to the same TX beam used for transmitting the given SRS resource. In accordance with an approach, the spatial relation info e.g. for SRS may be defined as follows:

SRS-SpatialRelationlnfo ::= SEQUENCE { servingCellld ServCelllndex OPTIONAL, - Need R referenceSignal CHOICE { ssb-index SSB-Index, csi-RS-Index NZP-CSI-RS-Resourceld, srs SEQUENCE { resourceld SRS-Resourceld, uplinkBWP BWB-Id }

}

}

According to an approach, the main procedures and functionalities in beam management are measurements and reporting of candidate reference signals that can act as a source to determine transmit and receive beam pair in downlink and in uplink, and beam indication / beam switching.

An assumption is that DL RSs are used for both DL and UL beam indication, wherein TX/RX beam correspondence is assumed at the UE. The UE is explicitly configured with SSB and/or CSL RS resources for Ll-RSRP measurements and reporting (CSI-RS framework). The UE may be configured with CSI-RS resource setting for up to 16 CSI-RS resource sets having up to 64 resources within each set. The total number of different CSI-RS resources over all resource sets may be, for example, no more than 128, in accordance with an approach. The UE may report the Ll-RSRP of {1, 2, 3 or 4} best SSBs or CSLRSs per report configuration. The reporting may comprise a resource index and an Ll-RSRP value.

In the beam indication / beam switching procedure the UE may be provided in downlink a TCI state for the target signal, based on which the UE can receive the target signal. According to an approach, the TCI state may be provided: with RRC configuration for P-CSLRS including TRS,

- with MAC-CE for PDCCH (one active TCI state per CORESET), SP-CSLRS, AP-CSL RS, PDSCH (when follows PDCCH), or with DCI for PDSCH, when explicit indication in use, and AP-CSLRS triggering of certain CSI-RS resource set(s).

In uplink the UE may be provided a spatial relation for the target signal based on which the UE forms the transmit beam. The provisioning of the spatial relation may be:

- RRC based for P-SRS,

- MAC-CE based for SP-SRS, AP-SRS, PUCCH, PUSCH, when follows PUCCH with resource ID = 0, or

DCI based indirectly for PUSCH wherein the DCI indicates reference SRS(s) so that UE shall transmit PUSCH with the same beam(s) as it transmitted given SRSs.

In the following, some default beam assumptions are defined according to an approach.

PDSCH:

If scheduling offset < timeDurationForQCL, then the TCI state is the one of the lowest CORESET ID in the latest slot monitored by UE. If scheduling offset >= timeDurationForQCL, then the TCI state is the one of the CORESET of the scheduling PDCCH if TCI state is not provided in the DCI, or PDSCH reception is based on the TCI state provided in DCI.

AP-CSI-RS:

If scheduling offset < beamSwitchTiming, then the UE either aligns the TCI state with an overlapping other signal TCI state or applies TCI state of the lowest CORESET ID in the latest slot monitored by UE.

PUCCH/SRS:

If spatial relation is not configured in FR2, the spatial relation may be determined as follows. In case when CORESET(s) are configured on the CC, the TCI state / QCL assumption follows the one of the CORESET with the lowest ID, or in case when any CORESETs are not configured on the CC, the activated TCI state with the lowest ID is applicable to PDSCH in the active DL-BWP of the CC.

PUSCH scheduled by DCI format 0 0:

When there are no PUCCH resources configured on the active UL BWP CC in FR2 and in RRC- connected mode, the default spatial relation may be the TCI state / QCL assumption of the CORESET with the lowest ID.

In multi-TRP scenario, TCI codepoint may comprise two TCI states and as a default beam case the UE assumes the TCI states of the TCI codepoint with the lowest ID (e.g. for PDSCH).

MAC CE based beam switching, i.e. activation of TCI state in downlink and activation of spatial relation RS in uplink may follow the following principles, in accordance with an approach: the UE may apply the new assumption 3 ms after the UE has sent the HARQ-ACK for the PDSCH carrying the MAC_CE.

A high-level illustration for the TCI state switching for the CORESET, i.e. for PDCCH reception, is given in Fig. 3. Beam Management defines a set of functionalities to assist UE to set its RX and TX beams for downlink receptions and uplink transmissions, respectively. The functionalities can be categorized roughly according to four groups: Beam Indication; Beam Acquisition, Measurements and Reporting; Beam Recovery; and Beam Tracking and Refinement.

Beam Indication may be used to assist the UE to set its RX and TX beam properly for the reception of DL and transmission ofUL, respectively.

Beam Acquisition, Measurements and Reporting include procedures for providing gNB knowledge about feasible DL and UL beams for the UE.

Beam Recovery is provided for rapid link reconfiguration against sudden blockages, i.e. fast realignment of gNB and UE beams.

Beam Tracking and Refinement comprises a set of procedures to refine gNB and UE side beams.

Regarding downlink beam management and especially for Beam Acquisition, Measurements and Reporting, the following beam management procedures are supported within one or multiple TRPs of the serving cell, in accordance with an approach. This is as also illustrated in Fig. 4.

A first procedure P-1, illustrated on the left of Fig. 4, may be used to enable UE measurement on different TRP Tx beams to support selection of TRP Tx beams/UE Rx beam(s). For beamforming at TRP, it may include an intra/inter-TRP Tx beam sweep from a set of different beams. For beamforming at the UE, it may include a UE Rx beam sweep from a set of different beams.

A second procedure P-2, illustrated in the middle of Fig. 4, may be used to enable UE measurement on different TRP Tx beams to possibly change inter/intra-TRP Tx beam(s). This may comprise using a possibly smaller set of beams for beam refinement than in the first procedure P-1. It should be noted that the second procedure P-2 can be a special case of the first procedure P-1.

A third procedure P-3, illustrated on the right of Fig. 4, may be used to enable UE measurement on the same TRP Tx beam to change UE Rx beam in the case UE uses beamforming. Regarding downlink beam indication a quasi-colocation (QCL) indication functionality has been defined. The principle to receive certain physical signal or physical channel may be: the UE is either configured with or the UE implicitly determines a source/reference RS that UE has received and measured earlier which defines how to set RX beam for the reception of the downlink (target) physical signal or channel to be received.

To provide the UE with QCL characteristics for the target signal (i.e. the signal to be received) a Transmission Coordination Indication (TCI) framework has been defined using which UE can be configured TCI state(s) to provide UE with source RS(s) for determining QCL characteristics. Each TCI state includes one or two source RSs that provide UE QCL TypeA, TypeB, TypeC and/or TypeD parameters. Different types may provide the parameters as follows:

QCL-TypeA: {Doppler shift, Doppler spread, average delay, delay spread}

QCL-TypeB: {Doppler shift, Doppler spread} QCL-TypeC: {Doppler shift, average delay} QCL-TypeD: {Spatial Rx parameter}

A unified TCI framework means that TCI states so far providing QCL assumptions for the reception of DL signals and channels would also be used to provide spatial sources for the transmission of UL signals and channels. Furthermore, the unified TCI framework defines the concept of indicated TCI state. The indicated TCI state can be a joint DL and UL TCI state or separate DL and separate UL TCI states. Indicated TCI state provides QCL source for downlink and spatial source for uplink for the set of downlink signals and channels and for the set of uplink signals and channels, respectively. In accordance with an approach, there can be one indicated joint DL and UL or one indicated DL and one indicate UL TCI state for the UE. However, the unified TCI framework may be extended so that there can be then multiple indicated DL and UL TCI states. Regarding the downlink Fig. 5 illustrates the concept.

In the following, some background for PDCCH, CORESET and search space set are provided as examples.

Channel Coding and Downlink Control Information (DCI) Construction The procedure for the gNB generating a PDCCH is illustrated in Fig. 6, in accordance with an approach. If the size of the DCI format 601 is less than 12 bits, a few zero padding bits will be appended until the payload size equals 12 bits. F or the DCI payload bits, a 24-bit cyclic redundancy check (CRC) is calculated 602 and appended to the payload. The CRC allows the UE to detect the presence of errors in the decoded DCI payload bits.

After the CRC is attached, the last 16 CRC bits are masked 603 with a corresponding identifier, referred to as a radio network temporary identifier (RNTI). Using the RNTI mask, the UE can detect the DCI for its unicast data and distinguish sets of DCI with different purposes that have the same payload size. The CRC attached bits are then interleaved 604 to distribute the CRC bits among the information bits. The interleaver supports a maximum input size of 164 bits. This means that a DCI without CRC can have at most 140 of payload bits. The bits are then encoded 605 by a Polar encoder to protect the DCI against errors during transmission. The encoder output is processed using a sub-block interleaver 606 and then rate matched 607 to fit the allocated payload resource elements (REs) of the DCI.

The payload bits of each DCI are separately scrambled 608 by a scrambling sequence generated from a length-31 Gold sequence. The scrambling sequence is initialized by the physical layer cell identity of the cell or by a UE specific scrambling identity and a UE specific cell RNTI (C-RNTI).

After the scrambled DCI bit sequence is Quadrature Phase Shift Keying (QPSK) modulated 609, the complex- valued modulation symbols are mapped 610 to physical resources in units referred to as control channel elements (CCEs) 611.

Each CCE consists of six resource element groups (REGs) 612, where a REG is defined as one PRB in one OFDM symbol which contains nine REs for the PDCCH payload and three demodulation reference signal (DMRS) REs.

For each DCI, 1, 2, 4, 8, or 16 CCEs can be allocated, where the number of CCEs for a DCI is denoted as aggregation level (AL). With QPSK modulation, a CCE contains 54 payload REs and therefore can carry 108 bits. This may need the output size of the rate matching block 613 to be L-108, where L is the associated AL. Based on the channel environment and available resources, the gNB can adaptively choose a proper aggregation level (AL) for a DCI to adjust the code rate.

Control Resource Sets (CORESETs)

A downlink control information (DCI) with aggregation level (AL) = L is mapped to physical resources in a given bandwidth part (BWP), where necessary parameters such as frequency and time domain resources, and scrambling sequence identity for the DMRS for the PDCCH are configured to a UE by means of the control resource set.

A UE may be configured with up to a certain number of coresets (e.g. three or five) for multi-DCI multi-TRP operation on each of up to four BWPs of a serving cell. In general, CORESETs are configured in units of six physical resource blocks (PRBs) on a six PRB frequency grid and one, two, or three consecutive OFDM symbols in the time domain.

A DCI of AL = L comprises L continuously numbered CCEs, and the CCEs are mapped on a number of REGs in a CORESET.

NR supports distributed and localized resource allocation for a DCI in a CORESET. This is done by configuring interleaved or non-interleaved CCE-to-REG mapping for each CORESET.

For interleaved CCE-to-REG mapping, REG bundles constituting the CCEs for a PDCCH are distributed in the frequency domain in units of REG bundles. A REG bundle is a set of indivisible resources consisting of neighboring REGs. A REG bundle spans across all OFDM symbols for the given CORESET. Once the REGs corresponding to a PDCCH are determined, the modulated symbols of the PDCCH are mapped to the REs of the determined REGs in the frequency domain first and the time domain second, i.e.in increasing order of the RE index and symbol index, respectively. PDCCH Monitoring - Search Space Sets (SSsets)

The UE performs blind decoding for a set of PDCCH candidates. PDCCH candidates to be monitored are configured for a UE by means of search space sets (SSsets). There are two search space set types: common search space (CSS) set, which is commonly monitored by a group of UEs in the cell, and UE-specific search space (USS) set, which is monitored by an individual UE.

A UE can be configured with up to 10 search space sets each for up to four BWPs in a serving cell. In general, the search space set configuration provides a UE with the search space set type (CSS set or USS set), DCI format(s) to be monitored, monitoring occasion, and the number of PDCCH candidates for each aggregation level in the search space set.

A search space set with index s is associated with only one CORESET with index p. The UE determines the slot for monitoring the SS set with index s based on the higher layer parameters for periodicity k, offset o, and duration d, where periodicity k and offset o provide a starting slot and duration d provides the number of consecutive slots where the search space set is monitored starting from the slot identified by k and o.

The IE SearchSpace defines how/where to search for PDCCH candidates. Each search space is associated with one ControlResourceSet. For a scheduled cell in the case of cross carrier scheduling, except for nrofCandidates, all the optional fields are absent (regardless of their presence conditions).

A common field configures this search space as common search space (CSS) and DCI formats to monitor.

A searchSpaceType field indicates whether this is a common search space (present) or a UE specific search space as well as DCI formats to monitor for.

A ue-Specific field configures this search space as UE specific search space (USS). The UE monitors the DCI format with CRC scrambled by C-RNTI, CS-RNTI (if configured), and SP-CSI- RNTI (if configured). PDCCH Monitoring - Receive beam assumption

The UE may be monitoring PDCCH on the certain CORESET based on the activated TCI state of the CORESET, if the CORESET is associated with CSS. The TCI state provides the UE with two QCL-Type source RSs at carrier frequencies where a receive beamforming is applied. One of the source RSs is the QCL-TypeD source based on which the UE is able to set its receive beam properly.

A principle is that the UE shall be able to receive PDCCH with the same reception (RX) beam as it used to receive the given QCL-TypeD source RS. Before the UE has been provided TCI state for PDCCH monitoring, the UE may apply the SSB used in the random access. A principle of receive beamforming for the PDCCH monitoring according to an approach is as follows.

If a UE is provided a zero value for searchSpacelD in PDCCH-ConfigCommon for a TypeO/OA/2- PDCCH CSS set, the UE determines monitoring occasions for PDCCH candidates of the Type0/0A/2-PDCCH CSS set, and the UE is provided a C-RNTI, the UE monitors PDCCH candidates only at monitoring occasions associated with a SS/PBCH block, where the SS/PBCH block is determined by the most recent of a MAC CE activation command indicating a TCI state of the active BWP that includes a CORESET with index 0, where the TCLstate includes a CSLRS which is quasi-co-located with the SS/PBCH block, or a random access procedure that is not initiated by a PDCCH order that triggers a contention-free random-access procedure.

For a CORESET other than a CORESET with index 0, one of two approaches may be utilized depending on whether the UE has not been provided a configuration of TCI state(s) or has been provided a configuration of more than one TCI states.

If the UE has not been provided a configuration of TCI state(s) by tci-StatesPDCCH-ToAddList and tci-StatesPDCCH-ToReleaseList for the CORESET, or has been provided initial configuration of more than one TCI states for the CORESET by tci-StatesPDCCH-ToAddList and tci- StatesPDCCH-ToReleaseList but has not received a MAC CE activation command for one of the TCI states, the UE assumes that the DM-RS antenna port associated with PDCCH receptions is quasi co-located with the SS/PBCH block the UE identified during the initial access procedure.

If the UE has been provided a configuration of more than one TCI states by tci-StatesPDCCH- ToAddList and tci-StatesPDCCH-ToReleaseList for the CORESET as part of Reconfiguration with sync procedure but has not received a MAC CE activation command for one of the TCI states, the UE assumes that the DM-RS antenna port associated with PDCCH receptions is quasi colocated with the SS/PBCH block or the CSI-RS resource the UE identified during the random access procedure initiated by the Reconfiguration with sync procedure.

For a CORESET with index 0, the UE assumes that a DM-RS antenna port for PDCCH receptions in the CORESET is quasi co-located with the one or more DL RS configured by a TCI state, where the TCI state is indicated by a MAC CE activation command for the CORESET, if any, or with a SS/PBCH block the UE identified during a most recent random-access procedure not initiated by a PDCCH order that triggers a contention- free random-access procedure, if no MAC CE activation command indicating a TCI state for the CORESET is received after the most recent random access procedure.

For the CORESET associated with USS the UE may apply the indicated TCI state that provides the QCL-TypeD RS based on which the UE determines its receive beam. The indicated TCI state is applied also corresponding PDSCH(s) (scheduled via the CORESET) and CSI-RS if configured to follow the indicated TCI state.

In the following, a method according to an embodiment will be described in more detail in connection with a user device UE and with reference to the flow diagram of Fig. 7a and the signalling chart of Fig. 7b.

The general solution comprises: the UE obtains one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used for physical downlink control channel, PDCCH, monitoring for a serving cell; and reports the one or more SSB identifiers to at least one of the serving cell and a non-serving cell. The UE may also report capability information to a network node, wherein the capability information indicates a TCI state capability.

More specifically, the one or more SSB identifiers is used to indicate the PDCCH monitoring, e.g. Typel-PDCCH and/or Type 1 -PDCCH, for data channel when the UE switches between the serving cell and non-serving cell. The reports of one or more SSB identifiers to the non-serving cell may go through the serving cell. The report of one or more SSB identifiers is at least send to the non-serving cell.

More detail of the solution is given as following. It should be noted that the sequence description in Fig. 7a or Fig.7b may be changed and some steps are optional or just for completion of a solution.

The UE 110 may indicate 751 by a first capability information message 701 to a serving cell of the network 100 that it can support only a single active TCI state at a time. The UE 110 may also indicate by a second capability information message 702 to the serving cell of the network 100 that it supports inter-cell beam management. It should be noted that the first capability information and the second capability information messages need not be separate messages, but they may also be combined.

As a response, the UE 110 receives 752 from the serving cell of the network 100 a first configuration message 703 including a configuration of CORESET(s) associated to CSS and CORESET(s) associated to USS.

The UE 110 may also receive 753 from the serving cell of the network 100 a second configuration message 704 of a configuration of Ll-RSRP reporting that includes configuration for SSB reporting from the serving cell based on which the UE may perform monitoring of PDCCH according to the CSS in the serving cell.

The UE 110 may receive 754 from the serving cell of the network 100 a third configuration message of a configuration, activation and indication of a new indicated TCI state. The current indicated TCI state includes QCL-Type RS(s) associated to PCI of the serving cell. The UE 110 may receive 755 a message 705 comprising an indication of the new indicated TCI state where the new indicated TCI state is having QCL-Type RS(s) associated to different PCI than the one of the serving cell.

The UE 110 monitors 706 PDCCH according to USS from a non-serving cell based on the indicated TCI state.

The UE 110 applies the indicated TCI state to all CORESET(s) and selects 707 an SSB based on which the UE 110 monitors PDCCH according to CSS.

The UE 110 provides 756 Ll-RSRP report that includes one entry for the selected SSB for the serving cell. Other entry/entries are providing best SSB or CSI-RSs among the configured SSB and/or CSI-RS resource pool for beam measurements.

The UE 110 may monitor 757, 710 CORESET(s) associated to CSS according to TypeO-PDCCH monitoring occasions that are defined by the SSB reported in the previous step 756.

The UE 110 may assume 758 that during the monitoring occasions of CORESET(s) associated to CSS and corresponding slots determined in the step 757 the UE does not monitor CORESET(s) associated to USS based in indicated TCI state.

The UE 110 may also assume 759 that in the slot where the UE monitored CORESET associated to CSS and potentially in the n slots after the UE does not monitor CORESET(s) associated to USS and/or UE does not assume any UE-dedicated PDSCH in those slots.

The UE 110 may assume 760 that during the monitoring occasions of CORESET(s) associated to CSS and corresponding slots not defined by the SSB reported in the step 757 the UE does monitor CORESET(s) associated to USS based in indicated TCI state in the non-serving cell. The non-serving cell avoids 711 transmitting PDCCH and PDSCH during the time the UE 110 is monitoring PDCCH in the serving cell and also during the time assumed for PDSCH and beam switching.

An alternative to SSB reporting of the serving cell could be that the UE reports the gNB time domain parameters like subframe(s), slot(s) and/or symbols when the UE cannot receive PDCCH and PDSCH as well as CSI-RS from the non-serving cell because of receiving PDCCH and possible PDSCH from the serving cell. In addition, the UE may provide as capability info a time margin that the UE needs always before and after the monitoring period used for the reception of PDCCH and potentially PDSCH from the serving cell during which the UE cannot be scheduled from the non-serving cell.

In 5G the first frequency range FR1 is 450 MHz - 6000 MHz, and the second frequency range FR2 is 24250 MHz - 52600 MHz, but in some other wireless communication systems these frequency ranges may differ from those used in 5G and it may also be possible that only one frequency range is in use or more than two separate frequency ranges are in use.

In the following, different exemplifying embodiments will be described using, as an example of an access architecture to which the embodiments may be applied, a radio access architecture based on Long Term Evolution Advanced (LTE Advanced, LTE-A) or new radio (NR, 5G), without restricting the embodiments to such an architecture, however. It is obvious for a person skilled in the art that the embodiments may also be applied to other kinds of communications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems are the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, the same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet protocol multimedia subsystems (IMS) or any combination thereof. Fig. 8 depicts examples of simplified system architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in Fig. 8 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in Fig. 8.

The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

The example of Fig. 8 shows a part of an exemplifying radio access network.

Fig. 8 shows user devices 110a and 110b configured to be in a wireless connection on one or more communication channels in a cell with an access node (such as (e/g)NodeB) 104 providing the cell. The physical link from a user device to a (e/g)NodeB is called uplink or reverse link and the physical link from the (e/g)NodeB to the user device is called downlink or forward link. It should be appreciated that (e/g)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

A communication system typically comprises more than one (e/g)NodeB in which case the (e/g)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signaling purposes. The (e/g)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The (e/g)NodeB includes or is coupled to transceivers. From the transceivers of the (e/g)NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (e/g)NodeB is further connected to core network 109 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providing connectivity of user devices (UEs) to external packet data networks, or mobile management entity (MME), etc. The CN may comprise network entities or nodes that may be referred to management entities. Examples of the network entities comprise at least an Access management Function (AMF).

The user device (also called a user device, a user terminal, a terminal device, a wireless device, a mobile station (MS) etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a user device may be implemented with a corresponding network apparatus, such as a relay node, an eNB, and an gNB. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station.

The user device typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and/or touch screen computer, tablet, game console, notebook, and multimedia device. It should be appreciated that a user device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A user device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to -human or human-to-computer interaction. The user device may also utilize cloud. In some applications, a user device may comprise a small portable device with radio parts (such as a watch, earphones or eyeglasses) and the computation is carried out in the cloud. The user device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user device functionalities. The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal or user device (UE) just to mention but a few names or apparatuses.

Various techniques described herein may also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals.

Additionally, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in Fig. 8) may be implemented.

5G enables using multiple input - multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in cooperation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and/or spectrum available. 5G mobile communications supports a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications (such as (massive) machine -type communications (mMTC), including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and also capable of being integrated with existing legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, at least in the early phase, as a system, where macro coverage is provided by the LTE and 5G radio interface access comes from small cells by aggregation to the LTE. In other words, 5G is planned to support both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz - cmWave, below 6GHz - cmWave - mmWave). One of the concepts considered to be used in 5G networks is network slicing in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G require to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

The communication system is also able to communicate with other networks, such as a public switched telephone network or the Internet 102, or utilize services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in Fig. 8 by “cloud” 102). The communication system may also comprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

Edge cloud may be brought into radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at the RAN side (in a distributed unit, DU 104) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 108).

It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Big Data and all-IP, which may change the way networks are being constructed and managed. 5G (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be applied in 4G networks as well. The gNB is a next generation Node B (or, new Node B) supporting the 5G network (i.e., the NR). 5G may also utilize satellite communication to enhance or complement the coverage of 5G service, for example by providing backhauling. Possible use cases are providing service continuity for machine -to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway/maritime/aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay node 104 or by a gNB located on-ground or in a satellite.

It is obvious for a person skilled in the art that the depicted system is only an example of a part of a radio access system and in practice, the system may comprise a plurality of (e/g)NodeBs, the user device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (e/g)NodeBs or may be a Home(e/g)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e/g)NodeBs of Fig. 8 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. Typically, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e/g)NodeBs are required to provide such a network structure.

For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” (e/g)NodeBs has been introduced. Typically, a network which is able to use “plug-and-play” (e/g)Node Bs, includes, in addition to Home (e/g)NodeBs (H(e/g)nodeBs), a home node B gateway, or HNB-GW (not shown in Fig. 8). A HNB Gateway (HNB-GW), which is typically installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network. Fig. 9 illustrates an example of a block diagram of an apparatus 110 in accordance with at least some embodiments of the present invention. The apparatus 110 may be, for example, a part of the resource manager. The apparatus 110 comprises a processor 1022, a memory 1024 and a transceiver 1024. The processor is operatively connected to the transceiver for controlling the transceiver. The apparatus may comprise a memory 1026. The memory may be operatively connected to the processor. It should be appreciated that the memory may be a separate memory or included to the processor and/or the transceiver. The memory 1026 may be used to store information, for example, configuration data, program code, and/or for some other information.

The operational units may be implemented as a computer code stored in the memory but they may also be implemented using hardware components or as a mixture of computer code and hardware components.

According to an embodiment, the processor is configured to control the transceiver and/or to perform one or more functionalities described with a method according to an embodiment.

A memory may be a computer readable medium that may be non-transitory. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multi-core processor architecture, as non-limiting examples.

Embodiments may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on memory, or any computer media. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "memory" or "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

Reference to, where relevant, "computer-readable storage medium", "computer program product", "tangibly embodied computer program" etc., or a "processor" or "processing circuitry" etc. should be understood to encompass not only computers having differing architectures such as single/multi-processor architectures and sequencers/parallel architectures, but also specialized circuits such as field programmable gate arrays FPGA, application specify circuits ASIC, signal processing devices and other devices. References to computer readable program code means, computer program, computer instructions, computer code etc. should be understood to express software for a programmable processor firmware such as the programmable content of a hardware device as instructions for a processor or configured or configuration settings for a fixed function device, gate array, programmable logic device, etc.

Although the above examples describe embodiments of the invention operating within a wireless device or a gNB, it would be appreciated that the invention as described above may be implemented as a part of any apparatus comprising a circuitry in which radio frequency signals are transmitted and/or received. Thus, for example, embodiments of the invention may be implemented in a mobile phone, in a base station, in a computer such as a desktop computer or a tablet computer comprising radio frequency communication means (e.g. wireless local area network, cellular radio, etc.).

In general, the various embodiments of the invention may be implemented in hardware or special purpose circuits or any combination thereof. While various aspects of the invention may be illustrated and described as block diagrams or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Embodiments of the inventions may be practiced in various components such as integrated circuit modules, field-programmable gate arrays (FPGA), application specific integrated circuits (ASIC), microcontrollers, microprocessors, a combination of such modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

Programs, such as those provided by Synopsys, Inc. of Mountain View, California and Cadence Design, of San Jose, California automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or "fab" for fabrication.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analogue and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable):

(i) a combination of analogue and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention.

Claims

1. An apparatus comprising at least one processor, and a transceiver, wherein the at least one processor is configured to: obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used to indicate physical downlink control channel, PDCCH, monitoring for a data channel when the apparatus switches between a serving cell and a nonserving cell; and wherein the transceiver is configured to: report the one or more SSB identifiers to the serving cell and/or the non-serving cell.

2. The apparatus according to claim 1, wherein the transceiver is further configured to: report capability information to a network node, wherein the capability information indicates a transmission configuration indicator, TCI, state capability.

3. The apparatus according to claim 1 or 2, wherein the transceiver is further configured to: monitor control signaling according to one or more SSB identifiers.

4. The apparatus according to claim 3, wherein the control signaling is associated to a typeO PDCCH monitoring occasions, wherein the typeO PDCCH monitoring occasions comprises the reported one or more SSB identifiers.

5. The apparatus according to any of the claims 1 to 4, wherein the obtain one or more synchronization signal block, SSB, identifiers comprises: receive the one or more synchronization signal block identifiers from a communication network; or determine the one or more synchronization signal block identifiers.

6. The apparatus according to claim 5, wherein the report the one or more SSB identifiers to at least one of the serving cell and a non-serving cell comprises:

39 report the one or more synchronization signal block identifiers to the serving cell of the communication network based on which the apparatus is configured to perform TypeO- PDCCH monitoring and/or Typel-PDCCH monitoring.

7. The apparatus according to any of the claims 1 to 6, wherein the at least one processor is configured to: omit monitoring dedicated PDCCH from non-serving cell during the time when the UE is monitoring TypeO-PDCCH and/or Typel-PDCCH in the serving cell on the occasions associated to the reported synchronization signal block.

8. The apparatus according to any of the claims 1 to 7, wherein the at least one processor is configured to: select the synchronization signal block for CSS monitoring out of a set of configured synchronization signal blocks.

9. The apparatus according to claim 8, wherein the report the one or more SSB identifiers to at least one of the serving cell and a non-serving cell comprises: report the selected synchronization signal block to the serving cell of the communication network.

10. A method comprising: obtaining, by a user device, one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used to indicate physical downlink control channel, PDCCH, monitoring for a data channel when the user device switches between a serving cell and a non-serving cell; and reporting, by the user device, the one or more SSB identifiers to at least one of the serving cell and the non-serving cell.

11. The method according to claim 10 comprising: reporting capability information to a network node, wherein the capability information indicates a transmission configuration indicator, TCI, state capability.

40

12. The method according to claim 10 or 11 comprising: monitoring control signaling according to one or more SSB identifiers.

13. The method according to claim 12, wherein the control signaling is associated to a typeO PDCCH monitoring occasions, wherein the typeO PDCCH monitoring occasions comprises the reported one or more SSB identifiers.

14. The method according to any of the claims 10 to 13, wherein the reporting, by the user device, the one or more SSB identifiers to at least one of the serving cell and a non-serving cell comprises: receiving the one or more SSB identifiers from a communication network; or determining the one or more SSB identifiers.

15. The method according to claim 14, wherein reporting the one or more SSB identifiers to at least one of the serving cell (S-BS) and a non-serving cell (N-BS) comprises: reporting the one or more synchronization signal block identifiers to the serving cell of the communication network (100) based on which the user device is configured to perform TypeO-PDCCH monitoring and/or Typel-PDCCH monitoring.

16. The method according to claim 10 to claim 15, further comprising: omitting monitoring dedicated PDCCH from non-serving cell (N-BS) during the time when the UE is monitoring TypeO-PDCCH and/or Typel-PDCCH in the serving cell (S-BS) on the occasions associated to the reported synchronization signal block.

17. The method according to claim 10 to claim 16, further comprising: selecting the synchronization signal block for CSS monitoring out of a set of configured synchronization signal blocks.

18. An apparatus comprising at least one processor; and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

41 obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used to indicate physical downlink control channel monitoring for a data channel when the apparatus switches between a serving cell and a non-serving cell; and report the one or more SSB identifiers to the serving cell and/or a non-serving cell.

19. The apparatus according to claim 18, the apparatus is further caused to: report capability information to a network node, wherein the capability information indicates a transmission configuration indicator, TCI, state capability.

20. The apparatus according to claim 18 or 19, the apparatus is further caused to: monitor control signaling according to one or more SSB identifiers.

21. The apparatus according to any of the claims 1 to 4, wherein obtaining one or more synchronization signal block, SSB, identifiers comprises: receive the one or more synchronization signal block identifiers from a communication network; or determine the one or more synchronization signal block identifiers.

22. A computer program comprising computer readable program code which, when executed by at least one processor; cause an apparatus to perform at least the following: obtain one or more synchronization signal block, SSB, identifiers, wherein the one or more SSB identifiers are used to indicate physical downlink control channel monitoring for a data channel when the apparatus switches between a serving cell and a non-serving cell; and report the one or more SSB identifiers to the serving cell and/or the non-serving cell.