User equipment, network node and methods performed therein

Abstract

Embodiments herein discloses, for example, a method performed by a network node (12) in a wireless communication network The network node (12) transmits a first synchronization indication and a second synchronization indication, towards a UE (10). The first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

Description

[0001] USER EQUIPMENT, NETWORK NODE AND METHODS PERFORMED THEREIN

[0002] TECHNICAL FIELD

[0003] Embodiments herein relate to a User Equipment (UE), a network node, and methods performed therein regarding wireless communication. Furthermore, a computer program product and a computer readable storage medium are also provided herein. In particular, embodiments herein relate to handling synchronization indications in a wireless communication network such as a non-terrestrial network (NTN).

[0004] BACKGROUND

[0005] In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and / or UEs, communicate via a Wide Area Network or a Local Area Network such as a Wi-Fi network or a cellular network comprising a Radio Access Network (RAN) part and a Core Network (CN) part. The RAN covers a geographical area which is divided into service areas or cell areas, which may also be referred to as a beam or a beam group, with each service area or cell area being served by a radio network node such as a radio access node e.g., a WiFi access point, a Base Station (BS) or a radio base station (RBS), which in some networks may also be denoted, for example, a Base Station (BS), a NodeB (NB), eNodeB (eNB), or gNodeB (gNB) as denoted in Fifth Generation (5G) telecommunications. A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on a radio frequency with the wireless devices within the range of the radio network node.

[0006] 3rd Generation Partnership Project (3GPP) is the standardization body for specifying the standards for the cellular system evolution, e.g., including 3G, 4G, 5G and the future evolutions such as 6G. Specifications for Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet System (EPS) have been completed within the 3GPP. In 4G also called a Fourth Generation (4G) network, EPS is core network and E- UTRA is radio access network. In 5G, 5G Core (5GC) is core network, NR is radio access network. As a continued network evolution, the new release of 3GPP specifies a 5G network also referred to as 5G New Radio (NR) and 5GC. Any network not located on earth is a Non-terrestrial Network (NTN), i.e., NTNs use satellites, drones, balloons, and / or the like, to transmit and receive radio for communication. Terrestrial networks (TN) are mainly the ordinary cellular networks that are used daily.

[0007] The main objective with NTNs is to provide coverage. This may be coverage over the ocean or other areas where it is difficult to deploy network towers. Coverage may also be needed during a rescue operation is a remote area where a drone may be used to provide a temporary network. A drone providing temporary coverage is often referred to as cell on wings (COW). A COW can also be used to provide a temporary capacity boost, e.g., if a large crowd of users are expected to spend time in a fairly remote area. There are a number of commercial NTN systems available, both standardized e.g., in 3GPP and proprietary.

[0008] Since Rel-17, there have been activities in 3GPP to standardize NTNs. There are two different 3GPP architectures available to realize satellite communication systems: transparent mode and regenerative mode.

[0009] In the transparent mode, the base station, such as a gNB or NB, is located on the ground behind a gateway. Thus, the satellite’s main purpose is to act as a repeater forwarding signals between the ground stations and the UE. The only processing that can be performed on the satellite is radio frequency processing, e.g., frequency conversion, amplification and beam management. Since the NB is on the ground the satellite in transparent architecture is simpler and requires less processing power. With simplicity comes less flexibility.

[0010] The regenerative architecture puts the entire NB, or at least parts of it, in the satellite, e.g., the radio unit is put in the satellite, which makes it possible to decode and process packets on the satellite. In this case the feeder link resembles the backhaul and / or fronthaul of a TN and is therefore not necessarily implemented using NR. Compared to the transparent architecture, the regenerative architecture provides more flexibility, better performance and the possibility for global coverage since it allows intersatellite links between satellites. Also, the satellite can process signals, rather than just relaying them.

[0011] Fig. 1 shows the different modes. Fig. 2 shows NTN Architecture Types. Although the transparent architecture is the one most used in deployments today, a semitransparent architecture, where the radio unit (Rll) is on-board the satellite, shows some promise of providing improved network scalability and performance. AAS in the Fig. 2 stands for Advanced Antenna System, CU for central unit and DU for distributed unit. For more technical details about Satellite Communication see: https: / / www.ericsson.com / 49bb0c / assets / local / reports-papers / ericsson-technology- review / docs / 2023 / 3gpp-satellite-communication.pdf.

[0012] An NTN base station system is also known as a Satellite Access Node (SAN) in 3GPP TS 38.108 v 18.0.1. In 3GPP Release 18 the SAN is depicted with the NTN payload radio frequency (RF) as comprising 3 logical functions. Fig. 3 shows the SAN NTN payload RF functions.

[0013] The current open RAN (ORAN) considerations are also relevant for NTN. For example, in Release 17 transparent architecture point 7 below is on the satellite and the rest points are terrestrial based. In regenerative architecture any of points 3 to 7 could be on satellite:

[0014] 1. Non applicable (N / A)

[0015] 2. N / A

[0016] 3. O-RAN Central Unit (O-CU): a logical node hosting radio resource control (RRC), Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) protocols

[0017] 4. O-RAN Central Unit - Control Plane (O-CU-CP): a logical node hosting the RRC and the control plane part of the PDCP protocol

[0018] 5. O-RAN Central Unit - User Plane (O-CU-UP): a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol

[0019] 6. O-RAN Distributed Unit (O-DU): a logical node hosting radio link control (RLC), medium access control (MAC), High-physical (PHY) layers based on a lower layer functional split.

[0020] 7. O-RAN Radio Unit (O-RU): a logical node hosting Low-PHY layer and radio frequency (RF) processing based on a lower layer functional split. This is similar to 3GPP’s transmission and reception point (TRP) or remote radio head (RRH) but more specific in including the Low-PHY layer such as e.g., fast fourier transform (FFT) and / or inverse FFT (iFFT), physical random access channel (PRACH) extraction.

[0021] Certain ORAN architecture terms are derived from 3GPP architecture terms. For example, the O-RU and O-DU are analogous to a 3GPP DU and the O-CU and near real time (RT)-RAN Intelligent Controller (RIC) are analogous to a 3GPP CU. Fig. 4 graphically depicts the correspondence of terms between basic ORAN architecture and 3GPP terminology. Thus, NTN was introduced for NR, LTE-machine type communication (MTC), and narrowband internet of things (NB-loT) in Rel-17. An overview of the functionalities added to NR for operating as a non-terrestrial network can be found in X. Lin et al., "5G from Space: An Overview of 3GPP", IEEE Communications Standards Magazine, vol. 5, no. 4, pp. 147-153, December 2021; M. S. Hassan et al., "NTN: from 5G NR to 6G," 2023 IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE), Aveiro, Portugal, 2023, pp. 173-178, doi: 10.1109 / WiSEE58383.2023.10289427; and NTN & Satellite in Rel-17 & 18, Munira Jaffar & Nicolas Chuberre, [Online], Available: https: / / www.3gpp.org / news-events / partner-news / ntn-rel17. In 3GPP Rel-19, NTN will continue to evolve and as part of its evolution the industry has considered downlink coverage enhancements for NR-NTN. The Rel-19 objective that is aiming to enhancing the downlink coverage is defined as follows RP-241667, “Revised WID: Non-Terrestrial Networks (NTN) for NR Phase 3”, 3GPP TSG RAN Meeting #104, Shanghai, China, June 17-20, 2024:

[0022] According to the following agreed satellite parameters for LEO 600 km for Set 1 in frequency range 1 (FR1) within the downlink coverage enhancement study, simultaneous active beams are 10.02%, 1.5% and 10.02% for Set 1-1, Set 1-2, and Set 1-3, respectively, see RP-241667, “Revised WID: Non-Terrestrial Networks (NTN) for NR Phase 3”, 3GPP TSG RAN Meeting #104, Shanghai, China, June 17-20, 2024. This determines the fraction of area that can be served under the satellite footprint. One way to increase the fraction of coverage area is to increase the number of simultaneous active beams. However, due to the power budget and number of RF chains available at the satellite payload, the number of active beams can’t be increased beyond certain limit. This eventually leads to the utilization of the so-called beam hopping, whereby one specific beam is used to illuminate multiple cells across different time instants.

[0023] Table 1. Additional reference satellite parameters for LEO 600 km Set 1-1 FR1.

[0024]

[0025] Table 2. Additional reference satellite parameters for LEO 600 km Set 1-2 FR1.

[0026] Table 3. Additional reference satellite parameters for LEO 600 km Set 1-3 FR1.

[0027] RAN1 also agreed to use the following methodology in the context of system-level evaluation of DL coverage enhancement during RAN1#116, see R1-2401769, Session notes for 9.11 (N on-Terrestrial Networks for NR Phase 3 and Internet of Things Phase 3), Ad-Hoc Chair (Huawei), RAN1#116, March 2024: For instance, consider Set 1-1 or Set 1-3. In this case, if a beam pattern consists of distinct 10% of beams which are activated each time instance to provide the coverage on the earth, then it requires total 10 time instances to cover the whole satellite footprint. After completing one such round, the first beam pattern gets its turn to serve again. The time involved between two instances of a beam in a specific beam pattern being active is called revisit time, Trevisit, which is limited by the timeline constraints imposed by the 5G NR mandatory common signals, e.g., synchronization signal block (SSB), system information block one (SIB) e.g., SIB1, SIB19, and / or the like, that facilitate the UE to access the network. For instance, the UEs in IDLE mode are expected to receive SSB once every 20 ms. SSB refers to Synchronization signal / physical broadcast channel (PBCH) block since a synchronization signal (SS) and PBCH channel are packed as a single block. If we base this as a revisit time interval, each beam in a beam pattern can only get 2 ms -interval to be active, called dwell time, Tdwell. Such a short interval of dwell time will not be sufficient to meet the traffic demands in each cell illuminated by a beam. Therefore, it is essential to increase the Trevisit such that there exists a reasonable dwell time for cells in beam hopping.

[0028] SUMMARY

[0029] As part of developing embodiments herein one or more issues have been identified that first will be described. Given that there exist a limited number of RF chains and limited power budget available at the satellite, it is not possible to cover the complete area under the satellite footprint, i.e. , the total number of active beam footprints that can be illuminated is always lower than the total number of beam footprints to be covered under the satellite footprint, equivalently, NTN cells. To address this, beam hopping may be used with each beam footprint hop over multiple cells in different time instances.

[0030] One way to increase the dwell time for cells illuminated by satellite beams and consequently increase the fraction of area that can be served under the satellite footprint is to increase the SSB periodicity for initial cell search longer than 20 ms, which won’t be compatible with NTN implementations prior to Rel-19 since the technical specification states the following, see 3GPP TS 38.213, “NR; Physical layer procedures for control,” V18.1.0.:

[0031] “For initial cell selection, a UE may assume that half frames with SS / PBCH blocks occur with a periodicity of 2 frames"

[0032] Thus, if SSB periodicities longer than 20 ms are to be introduced as part of the downlink coverage enhancement techniques, then there will be an impact in the above statement and therefore on what NTN implementations prior to Rel-19 assume to occur during initial cell selection.

[0033] Alternative way to address this issue is to increase the size of beam footprint that is mapped to cells such that there exist reduced number of beam footprints within a wireless communication network footprint such as a satellite footprint. This will allow for increased dwell times for a fixed revisit time and SSB periodicity compared to narrower beam footprints. In this case, capacity and coverage are subject to the beam footprint size and traffic demands. Furthermore, the idea of combination of wider and narrower beam footprints may be considered in this context. However, how to select between wider and narrower beam footprints for the signal transmission and desired narrow beam footprint with respect to the UE within the wider beam footprint is not straightforward and readily supported with the existing specifications.

[0034] Thus, an object of embodiments herein is to provide a mechanism that handles communication in a wireless communication network, such as an NTN, efficiently.

[0035] According to an aspect the object is achieved by providing a method performed by a network node for handling synchronization indications in a wireless communication network, e.g. a radio access network node, or a satellite-based access node, such as a SAN or a node in connection with a SAN of an NTN. The network node transmits a first synchronization indication and a second synchronization indication, towards a UE. The first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

[0036] The network node may transmit the first synchronization indication and the second synchronization indication towards the UE, in one or more footprint or spot beams configured to serve or cover the UE. The first synchronization indication is of the first type and the second synchronization indication is of the second type. The first type may be a non-punctured SSB and the second type may be a punctured SSB or a cell defining SSB (CD-SSB). Thus, the network node may perform a dual transmission, transmissions in parallel or simultaneous transmission of the first and second type of synchronization indications.

[0037] The network node may perform one or more of the following:

[0038] Dual SSB transmissions, of such as punctured and non-punctured SSBs, at different sync-raster points. • Dual SSB transmissions, of such as punctured and non-punctured SSBs, at the same sync-raster point.

[0039] • Single SSB during initial access and Dual SSB transmissions, of such as nonpunctured SSB and non-CD SSB, during connected-mode.

[0040] • Dual SSB transmissions, of such as punctured and / or non-punctured SSB, in different frequencies of a specific band during initial access

[0041] According to another aspect the object is achieved by providing a method performed by a UE for handling synchronization indications in a wireless communication network such as in an NTN. The UE receives from network node, a synchronization indication being one out of a first synchronization indication and a second synchronization indication. The first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

[0042] The UE may receive one or more SSBs in a first beam footprint, wherein the first beam footprint covers two or more second beam footprints. The UE may then communicate with the network node by performing communication between the network node and the UE, data and / or one or more SSBs over one or more second beam footprints and / or the first beam footprint. As an example, the UE may receive one or more synchronization indications such as SSBs from the network node over a wider beam footprint generated by the network node. The wider beam footprint may cover two or more narrower beam footprints. The UE may then communicate i.e., receive and / or transmit other data and / or SSB over a narrower beam footprint and / or the wider beam footprint.

[0043] According to another aspect the object is achieved by providing a network node and a UE configured to perform the methods herein.

[0044] Thus, according to an aspect the object is achieved by providing a network node for handling synchronization indications in a wireless communication network. The network node is configured to transmit a first synchronization indication and a second synchronization indication, towards a UE. The first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

[0045] According to still another aspect the object is achieved by providing a UE for handling synchronization indications in a wireless communication network. The UE is configured to receive from a network node, a synchronization indication being one out of a first synchronization indication and a second synchronization indication. The first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

[0046] It is furthermore provided herein a computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out the methods herein, as performed by the UE and the network node, respectively. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the methods herein, as performed by the UE and the network node, respectively.

[0047] Embodiments herein may enable co-existence of UEs supporting only a 20 ms SSB periodicity during initial cell selection, with UEs supporting SSB periodicities longer than 20 ms during initial cell selection. The one or more of the following may be performed:

[0048] • Dual SSB transmissions, such as punctured and non-punctured SSB, at different sync-raster points.

[0049] • Dual SSB transmissions, such as punctured and non-punctured SSB, at the same sync-raster point.

[0050] • Single SSB during initial access and Dual SSB transmissions, such as nonpunctured SSB and non CD-SSB, during connected-mode.

[0051] • Dual SSB transmissions, such as punctured and / or non-punctured SSB, in different frequencies of a specific band during initial access.

[0052] Embodiments herein may provide one or more of the following advantages:

[0053] • Backward compatibility: The techniques under discussion for enhancing the downlink coverage for NR-NTN in Rel-19, i.e. , “Beam Hopping,” “Satellite beam width”, and “Frequency Re-use”, may be usable by UEs supporting only early releases of NTN i.e., releases prior to Rel-19.

[0054] • Example embodiments herein make-use and / or combine in a novel way features to minimize specification impacts.

[0055] • Due to the fact that SSB and other channels and / or signals used for handover are using the wider beam footprints, the handover occurrence may be reduced by a factor of / V = C / c, where C is the area of the wider beam footprint, and c is the area of the narrower beam footprint. Thue, embodiments herein provide a mechanism that efficiently handles communication in a wireless communication network such as an NTN.

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Examples of embodiments herein are described in more detail with reference to attached drawings in which: Figs. 1-4 are schematic overviews depicting prior art, Fig. 5 is a schematic block diagram illustrating embodiments of a wireless communication network,

[0058] Figs. 6 to 12 are illustrations of example embodiments herein,

[0059] Fig. 13 is a schematic block diagram illustrating embodiments of a network node,

[0060] Fig. 14 is a schematic block diagram illustrating embodiments of a UE,

[0061] Fig. 15 schematically illustrates embodiments of a communication system, Fig. 16 is a generalized block diagram of embodiments of a UE,

[0062] Fig. 17 is a generalized block diagram of embodiments of a network node

[0063] Fig. 18 is a generalized block diagram of embodiments of a virtualization environment;

[0064] Fig. 19 shows PDCCH link-level performance in terms of initial BLER versus SNR Figs. 20-23 show link-level performance according to embodiments herein;

[0065] Fig. 24 shows directions in a coordination system; and Fig. 25 shows a coordination system.

[0066] DETAILED DESCRIPTION

[0067] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0068] Embodiments herein relate to wireless communications networks in general. Fig. 5 is a schematic overview depicting a wireless communication network 1 . The wireless communication network 1 may comprise one or more RANs and one or more CNs. The wireless communications network 1 may use one or a number of different technologies. The wireless communication network 1 may include a non-terrestrial network, NTN, such as a satellite communication system. The satellite communication system may be arranged as in a transparent mode or a regenerative mode. Embodiments herein relate to recent technology trends that are of particular interest in a New Radio (NR) and 6G context, however, embodiments are also applicable in existing wireless communications systems such as e.g. LTE or Wideband Code Division Multiple Access (WCDMA), and developments thereof.

[0069] In the wireless communication network 1, a user equipment (UE) 10, exemplified herein as a wireless device such as a mobile station, a non-access point (non-AP) station (STA), a STA and / or a wireless terminal, is comprised communicating via e.g. one or more Access Networks (AN), e.g. RAN, to one or more CNs. It should be understood by the skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communications terminal, user equipment, narrowband internet of things (NB-loT) device, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, smart glasses, smart watch, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station capable of communicating using radio communication with a radio network node within an area served by the radio network node.

[0070] The wireless communication network 1 comprises a network node 12 providing radio coverage over a geographical area, a first service area 11 or first cell, of a first radio access technology (RAT), such as 6G, NR, LTE, or similar. The network node 12 may be a satellite based access node, a SAN, a SAN connected to an access point, such as a transmission and reception point, a RAN node, an access controller, a base station, e.g. a radio base station such as a gNB, an eNB, an NB, a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA), a transmission arrangement of a radio base station, a stand-alone access point or any other network unit or node capable of communicating with a wireless device within the area served by the radio network node depending e.g. on the first radio access technology and terminology used. The network node 12 may be referred to as a serving network node wherein the service area may be referred to as a serving cell, and the serving network node communicates with the UE 10 in form of DL transmissions to the UE 10 and UL transmissions from the UE 10. It should be noted that a service area may be denoted as cell, spot beam, satellite footprint, beam group or similar to define an area of radio coverage.

[0071] The respective node may be a standalone server, a cloud-implemented server, a distributed server or processing resources in a server farm or same node. Embodiments herein may be implemented as physical bare metal, virtual or cloud native such as Kubernetes environment in, e.g., hyper-cloud networks. According to embodiments herein, the network node 12 transmits a first synchronization indication and a second synchronization indication towards the UE 10, in, for example, one or more footprint or spot beams configured to serve or cover the UE 10. The first synchronization indication is of a first type and the second synchronization indication is of a second type. The first synchronization indication is transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point. The first type may be a non-punctured SSB and the second type may be a punctured SSB or a CD-SSB. Punctured SSB may comprise a punctured PBCH reducing resource blocks of a PBCH. Thus, the network node 12 may perform a dual transmission, transmissions in parallel or simultaneous transmission of the first and second type of synchronization indications.

[0072] The network node 12 may perform one or more of the following:

[0073] • Dual SSB transmissions, such as punctured and non-punctured SSBs, at different sync-raster points.

[0074] • Dual SSB transmissions, such as punctured and non-punctured SSBs, at the same sync-raster point.

[0075] • Single SSB during initial access and Dual SSB transmissions, such as nonpunctured SSB and non-cell defining (NCD) SSB, during connected-mode.

[0076] • Dual SSB transmissions, such as punctured and / or non-punctured SSBs, in different frequencies of a specific band during initial access

[0077] As an example, the network node 12 transmits one or more synchronization indications such as SSBs towards the UE 10 over a narrower footprint or spot beam, and / or a wider footprint or spot beam generated by the network node 12, wherein the wider footprint or spot beam covers, at least partly, two or more narrower footprints or spot beams. For example, the network node 12 may transmit a single SSB with a periodicity of a default value during initial access over a wider footprint or spot beam. Remaining physical channels and signals may be transmitted to the UE 10 or be received from the UE 10 over the wider and / or narrower footprint or spot beam in each cell. Thus, the network node 12 may transmit SSBs and / or other data over wider beam footprints and narrower beam footprints such that a satellite footprint is partitioned into multiple wider cells or areas hosting multiple regions that are covered by narrower beam footprints.

[0078] The network node 12 may initiate a communication, towards the UE 10, of one or more synchronization indications, such as SSBs, in one or more beam footprints configured to serve or cover the UE 10. The method may be for handling communications in the wireless communication network such as an NTN. The terms beam footprint, spot beam, satellite footprint, beam, footprint are used interchangeably throughout the disclosure.

[0079] The communication may comprise transmitting one or more SSBs in a first beam footprint. The first beam footprint covers, at least partly, two or more second beam footprints. The communication may further comprise communicating between the network node 12 and the UE 10, data and / or one or more SSBs over one or more second beam footprints and / or the first beam footprint. As an example, the network node 12 may transmit one or more synchronization indications such as SSBs towards the UE 10 over a narrower footprint or spot beam and / or a wider footprint or spot beam generated by the network node 12, wherein the wider footprint or spot beam covers two or more narrower footprints or spot beams. The network node 12 and the UE 10 may then communicate other data and / or SSB over a narrower footprint or spot beam and / or the wider footprint or spot beam.

[0080] Towards the introduction of Rel-19 downlink coverage enhancements for NR-NTN,

[0081] • Beam hopping scheme with beam footprints sizes may be optimized to increase the dwell times for cells under the satellite footprint. Specifically, there exist wider beam footprints and narrower beam footprints such that satellite footprint is partitioned into multiple wider cell areas, each is illuminated by wider beam footprint and each wider cell hosts multiple regions that are covered by narrow beam footprints. A single SSB may be transmitted with periodicity default value such as a value of 20 ms or larger than 20 ms during initial access over wider beam footprint. The remaining physical channels and signals to be transmitted to the UE 10 or to be received from the UE 10 are partitioned between wider and narrower beam footprints in each cell.

[0082] Additionally, one or more of the following example embodiments are provided for allowing the co-existence of UEs such as UE 10 supporting only a 20 ms SSB periodicity during initial cell selection, with UEs e.g., UE 10 supporting SSB periodicities longer than 20 ms during initial cell selection:

[0083] • Dual SSB transmissions, such as punctured and non-punctured SSBs, at different sync-raster points.

[0084] • Dual SSB transmissions, such as punctured and non-punctured SSBs, at the same sync-raster point. • Single SSB during initial access and Dual SSB transmissions, such as nonpunctured SSB and NCD-SSB, during connected-mode.

[0085] • Dual SSB transmissions, such as punctured and / or non-punctured SSBs, in different frequencies of a specific band during initial access

[0086] For all solutions, after connection establishment and once in connected-mode, the periodicities of the non-punctured SSB and the punctured SSB or NCD-SSB may optionally be aligned as to use both a long periodicity, e.g., an SSB periodicity of 160 ms.

[0087] Beam hopping scheme with combination of wider and narrower beam footprints: There exist wider beam footprints and narrower beam footprints such that satellite footprint is partitioned into multiple wider cell areas. As shown in Fig. 6, each wider cell is illuminated by wider beam footprint and each wider cell hosts multiple regions that are covered by narrow beam footprints. For instance, narrower beam footprints correspond to beam diameter in the range of 40 to 50 km while wider beam footprints correspond to beam diameter at least in the range of 75 km, but not limited to it. Fig. 6 is an illustration of beam hopping utilizing combination of wider and narrower beam footprints, whereby DL common channels are transmitted over the wider beam footprint area as shown in a) and wider beam footprint area hosts multiple, e.g., two, narrower beam footprints over which the DL / LIL dedicated channels may be transmitted as shown in b), subject to the coverage and capacity requirements.

[0088] Wider beam footprint may be achieved in two ways: 1) by keeping the same beamwidth but using the lower power contour lines or 2) by keeping the same power contour lines but using higher beamwidths, where a contour line is a line of specific attenuation compared to the center of the cells, e.g., -3 dB or -5 dB, and / or the like, as illustrated in Fig. 7. Width of beams may be managed by number of active antenna elements and level of power. Thus, wider beam footprints may use higher power, more active antenna elements, lower power contour lines or similar. Fig. 7 shows two different ways for creating beam footprints mapped to wider cells. 1) using lower power contours of the same beam as shown on the left, 2) widening the beam as shown on the right.

[0089] A single SSB may be transmitted with periodicity default value of 20 ms or larger than 20 ms during initial access over wider beam footprint. The remaining physical channels and signals to be transmitted to the UE 10 or to be received from the UE 10 may be partitioned over wider and narrower beam footprints in each cell. • In one embodiment, PRACH transmission over wider beam footprint does not meet the link budget requirements. In that case, one SSB is transmitted over wider beam footprint as in the legacy. SIB1 may be transmitted over wider beam footprint, which indicates the UE 10 about the partitioning of random access channel (RACH) occasions with respect to narrower beam footprints within the system information which is a new indication. For instance, RACH occasion 1 may use, or may be for, narrower beam footprint 1 while RACH occasion 2 may use, or may be for, narrower beam footprint 2, and / or the like. The network node 12 may transmit channel state information reference signal (CSI-RS) over multiple narrower beams, wherein one narrower beam may be transmitted over a different time instance than another narrower beam. Then, the UE 10 may identify a best CSI-RS transmission among all and may then trigger PRACH transmission in the time instance related to a RACH occasion corresponding to the desired narrower beam footprint. Based on this, subsequent channels and / or signals may be transmitted and / or received over the narrower beam footprint. And one or more of the physical channels and signals may be transmitted over wider beam footprint if the corresponding link budget requirements are satisfied. Furthermore, in the current technical specifications for release 18 of the 3GPP standard, e.g. 3GPP TS 38.331 version 18.3.0, 3GPP TS 38.213 version 18.4.0 and 3GPP TS 38.321 version 18.3.0, it is described how RACH occasions, also referred to as PRACH occasions, i.e. UL time-frequency resources dedicated for transmissions of random access (RA) preambles, can be distributed in the time and frequency domains such that one or each RACH occasion is associated with a, certain, SSB or SSB index, or one or each RACH occasion in combination with a certain RA preamble range are associated with a, certain, SSB or SSB index. In some embodiments, a new type of RACH occasion allocation and association configuration is introduced, whereby RACH occasions are associated with CSI- RSs, e.g., CSI-RS indexes or CSI-RS resource IDs. To this end, a new type of configuration associates a respective RACH occasion, or a respective RACH occasion in combination with a certain RA preamble range, e.g., indicated by preamble indexes, with a CSI-RS, e.g. a CSI-RS index or a CSI-RS resource ID, e.g., in a similar way as each RACH occasion, or each RACH occasion in combination with a certain RA preamble range, is associated with an SSB or SSB index according to the current 3GPP technical specifications. Note that according to the current 3GPP technical specifications, as one option, multiple SSBs, or SSB indexes, may be associated with the same RACH occasion, in which case each of the SSBs associated with the same RACH occasion is associated with a separate RA preamble range, e.g., a subset of the cell’s entire RA preamble range. Hence, the RACH occasion the UE 10 uses, or the combination of RACH occasion and RA preamble range, i.e. , the range or subrange which the UE’s transmitted RA preamble belongs to, may indicate to the network node 12 which SSB the UE 10 has selected. The same principle may be used in these embodiments, albeit using CSI-RSs, e.g., CSI-RS indexes or CSI-RS resource IDs, instead of SSBs.

[0090] • In another embodiment, PRACH transmission over a wider beam footprint may meet the link budget requirements. In that case, one SSB and SIB1 may be transmitted over wider beam footprint i.e., as in the legacy. PRACH may be transmitted over wider beam footprint. In the next step, the network node 12 may transmit CSI-RS over multiple narrower beams, each one at a different time instance. Then, the UE 10 may identify the best CSI-RS transmission among all and may report back the favourable CSI-RS transmission based on which the network node 12 may identify the desired narrower beam footprint for the UE 10. Based on this, subsequent channels and / or signals may be transmitted and / or received over narrow beam footprint. And some of the physical channels and signals may be transmitted over wider beam footprint if one or more corresponding link budget requirements are satisfied.

[0091] • The network node 12 and the UE 10 may leverage reference points, which also may be referred to as reference locations, i.e., geographical locations, e.g., indicated as geographical coordinates, in two or three dimensions, to make the UE 10 select the most suitable narrower beam footprint and / or select suitable signalling occasions or time-frequency resources to be used for transmission or reception of a certain signal or message and / or to select suitable configurations or configuration options. As an extension to that solution, in other embodiments, the network node 12 may broadcast reference locations corresponding to the geographical centers of narrow beam footprints within the system information, e.g., ReferenceLocationNB1-R19, ReferenceLocationNB2-R19 within SIB19 or SIBI or any other SIB. The network node 12 may indicate the UE 10 about the partitioning of RACH occasions with respect to narrow beam footprints within the system information, e.g., in SIB1 or SIB19. For instance, RACH occasion 1 is for narrower beam footprint 1 while RACH occasion 2 is for narrower beam footprint 2. The UE 10 may receive the broadcasted reference points, may compare its own location with the reference points and may select the resources, occasions and / or configurations associated with the reference point that is the closest to the UE’s own location. In addition, in some embodiments, the reference points, and their distances to the UE’s own location, may be leveraged in other ways to identify e.g. the instance of a paging occasion that is associated with the UE’s most appropriate narrow beam, i.e. the instance of a paging occasion in which the network node 12 may transmit a paging message in the UE’s narrow beam, assuming thus that paging messages are beam swept, i.e. transmitted multiple times in sequence, across the narrow beams, in a similar way as paging is beam swept across SSB beams in the existing 3GPP standard.

[0092] Dual SSB transmissions, of punctured and non-punctured SSBs, at different sync-raster points.

[0093] In one embodiment, one or more UEs such as e.g., UE 10 perform initial cell selection at one or more of the synchronization raster points located within the maximum transmission bandwidth of a given channel bandwidth of a cell such as an NR NTN cell. The network node 12 may perform a Dual SSB transmission at two different synchronization raster points in such a way that UEs supporting an SSB periodicity of 20 ms may receive one or more non-punctured SSBs, wherein SSB may be SS / PBCH block at one synchronization raster point, whereas UEs supporting SSB periodicities longer than 20 ms may receive one or more punctured SSB at a different synchronization raster point.

[0094] In one dependent embodiment, the one or more non-punctured SSBs may encompass each 20-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0095] In one dependent embodiment, the one or more non-punctured SSBs may be configured with any of the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values. An SSB periodicity of 20 ms may be used during initial cell selection.

[0096] In one dependent embodiment, the one or more punctured SSBs may encompass each 12-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0097] In one dependent embodiment, the one or more punctured SSBs may be configured with at least the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values, and possibly one or more entries longer than 160 ms. An SSB periodicity equal or greater than 20 ms may be used during initial cell selection.

[0098] Fig. 8 shows dual SSB transmissions, such as punctured and non-punctured SSBs, at different synchronization raster points In one embodiment, after connection establishment and once the UEs are in connected-mode, the Dual SSB transmission at two different synchronization raster points may optionally align the SSB periodicities up to 160 ms, which is the longest SSB periodicity supported by those UEs that may only support a 20 ms SSB periodicity during initial cell selection.

[0099] Dual SSB transmissions, such as punctured and non-punctured SSBs, at the same synchronization raster point.

[0100] In one embodiment, one or more UEs perform initial cell selection at one of the synchronization raster points located within the maximum transmission bandwidth of a given channel bandwidth of an NR NTN cell. The network node 12 may perform a Dual SSB transmission at the same synchronization raster point in different time locations in such a way that UEs supporting an SSB periodicity of 20 ms may receive one or more non-punctured SSBs in a first position in time, e.g., within a half-frame, whereas UEs supporting SSB periodicities longer than 20 ms may receive one or more punctured SSB in a second position in time, e.g., at a later position within the same half-frame.

[0101] In one dependent embodiment, the time location where the one or more nonpunctured SSBs and the one or more punctured SSB received may be inverted. That is, UEs supporting SSB periodicities longer than 20 ms may receive one or more punctured SSB at the same synchronization raster point in a first position in time, e.g., within a halfframe, whereas UEs supporting an SSB periodicity of 20 ms may receive one or more non-punctured SSBs at the same synchronization raster point in a second position in time, e.g., at a later position within the same half-frame.

[0102] In one dependent embodiment, from among the SSB indices transmitted in halfframe and when each SSB index may be associated to a different cell, one SSB index may be associated with a cell operating with a 20 ms SSB periodicity, whereas one other SSB index may be associated with a cell operating with a longer SSB periodicity, e.g., 160 ms.

[0103] In one dependent embodiment, the SSB indices may be assigned one-by-one and without repetition to one or more cells during the cell planning and without requiring any signaling to coordinate the SSB indices assignment between cells.

[0104] In one dependent embodiment, the one or more non-punctured SSBs may encompass each 20-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0105] In one dependent embodiment, the one or more non-punctured SSBs may be configured with any of the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values. An SSB periodicity of 20 ms may be used during initial cell selection.

[0106] In one dependent embodiment, the one or more punctured SSBs may encompass each 12-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0107] In one dependent embodiment, the one or more punctured SSBs may be configured with at least the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values, and possibly one or more entries longer than 160 ms. An SSB periodicity equal to or greater than 20 ms may be used during initial cell selection.

[0108] Fig. 9 shows dual SSB transmissions, such as punctured and non-punctured SSBs, at the same synchronization raster point in different time locations.

[0109] In one embodiment, after connection establishment and once the UEs such as e.g., UE 10 are in connected-mode, the Dual SSB transmission occurring at the same syncraster points may optionally align the SSB periodicities up to 160 ms, which is the longest SSB periodicity supported by those UEs that may only support a 20 ms SSB periodicity during initial cell selection.

[0110] In one embodiment, the UEs supporting SSB periodicities longer than 20 ms may also support the legacy 20 ms SSB periodicity, in which case the UE 10 hypothesize on the SSB periodicity being used at a given NTN cell, e.g., through first testing over an observation period of 80 ms given by master information block (MIB) as to perform PBCH combining when a legacy 20 ms SSB periodicity is used.

[0111] As an alternative to the previous embodiment, an indication or pre-knowledge may be used by the UEs supporting SSB periodicities longer than 20 ms during initial cell selection to determine the SSB periodicity being used at a given NTN cell.

[0112] In one dependent embodiment, the signature, indication, or pre-knowledge used by a given UE 10 supporting SSB periodicities longer than 20 ms during initial cell selection may for example consist in defining specific synchronization raster points where the dual SS transmission may be predefined as to transmit first one or more non-punctured SSBs that precede a second one or more punctured SSBs. Alternatively, the order may be inverted predefining that first one or more punctured SSBs precede a one or more nonpunctured SSBs.

[0113] Single SSB during initial access and Dual SSB transmissions, such as non-punctured SSB and NCD-SSB, during connected-mode.

[0114] In one embodiment, one or more UEs may perform initial cell selection across the synchronization raster points located within the maximum transmission bandwidth of a given channel bandwidth of an NR NTN cell. The network node 12 may transmit one or more non-punctured SSBs at one synchronization raster point using an SSB periodicity of 20 ms, then after connection establishment and once the UEs are in connected-mode the network node 12 may perform a Dual SSB transmission at two different synchronization raster points in such a way that UEs supporting an SSB periodicity of 20 ms may receive one or more non-punctured SSBs at a given synchronization raster point, whereas UEs supporting SSB periodicities longer than 20 ms may receive one or more non-cell defining SSB at a different synchronization raster point.

[0115] Fig. 10 shows a procedure for transmitting a single SSB during initial access and Dual SSB transmissions, such as non-punctured SSB, or CD-SSB, and NCD-SSB, during connected-mode.

[0116] In one dependent embodiment, the one or more non-punctured SSBs may encompass each 20 PRBs in the frequency-domain and 4 symbols in the time-domain.

[0117] In one dependent embodiment, the one or more non-cell defining SSBs may be non-punctured encompassing each 20-PRBs in the frequency-domain and 4 symbols in the time-domain, or the one or more non-cell defining SSBs may be punctured encompassing each 12 PRBs in the frequency-domain and 4 symbols in the time-domain.

[0118] In one dependent embodiment, the one or more NCD-SSBs may be configured with at least the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values, and possibly one or more entries longer than 160 ms.

[0119] In one embodiment, after connection establishment and once the UEs are in connected-mode, the Dual SSB transmission at two different synchronization raster points may optionally align the SSB periodicities up to 160 ms, which is the longest SSB periodicity supported by those UEs that may only support a 20 ms SSB periodicity during initial cell selection.

[0120] Dual SSB transmissions, such as punctured and / or non-punctured SSBs, in different frequencies of a specific band during initial access.

[0121] Fig. 11 shows an NTN band that is partitioned into two parts with Frequencyl is used by cells mapped to wider beams and SSB periodicity of 20 ms and Frequency 2 is used by cells mapped to narrower beams and SSB periodicity larger than 20 ms.

[0122] In one embodiment, an NTN band or a subset of a band, e.g., the transmission bandwidth of a channel bandwidth, may be partitioned into two parts and each part is assigned to support SSB with a specific periodicity as illustrated in Fig. 11. For instance, SSB with periodicity 20 ms may be supported on one frequency while SSB with periodicity larger than 20 ms may be supported on the other frequency. This allows support prior to rel-19 UEs as well as rel-19 UE on one frequency while rel-19 UEs are supported also on the other frequency. The network node 12 may configure the cellBarred within MIB of SSB to prohibit a subset of UEs to connect using a specific SSB during cell search. Specifically, the total number of beams produced by a satellite station may be partitioned into two sets and may be assigned across two frequencies corresponding to different SSB periodicities. The beams associated with one frequency corresponding to SSB periodicity larger than 20 ms may operate on relatively narrower and hence may map to cover relatively smaller cell sizes compared to the beams associated with the other frequency corresponding to SSB periodicity 20 ms, which may map to larger cell sizes. In one embodiment, to facilitate the mapping of beam to larger cell size, scalable adjacent beam spacing may be utilized such that beam spacing may be increased without increasing half-power beamwidth of the antenna. This allows to maintain the maximum antenna gain for a given aperture size and number of antenna elements and antenna element spacing.

[0123] In one embodiment, the coverage regions of wider and narrower cells may or may not be overlapping completely and / or partially depending on the beam to cell mapping and traffic demands.

[0124] In one embodiment, the SSB corresponding to periodicity larger than 20 ms may be either punctured or non-punctured while the SSB with 20 ms periodicity may be a nonpunctured one.

[0125] In one dependent embodiment, the one or more non-punctured SSBs may encompass each 20-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0126] In one dependent embodiment, the one or more non-punctured SSBs may be configured with any of the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values; wherein an SSB periodicity of 20 ms may be used during initial cell selection.

[0127] In one dependent embodiment, the one or more punctured SSBs may encompass each 12-PRBs in the frequency-domain and 4 symbols in the time-domain.

[0128] In one dependent embodiment, the one or more punctured SSBs may be configured with at least the following SSB periodicities 40 ms, 80 ms, and 160 ms, but not limited to these values, and possibly one or more entries longer than 160 ms; wherein an SSB periodicity equal or greater than 20 ms may be used during initial cell selection.

[0129] In another embodiment, the network node 12 may assign the number of beams to each frequency depending on the traffic demands geographically within a satellite coverage region, subject to the total power budget available for sharing across the beams. In another embodiment, to improve the coverage of the subset of UEs that may be in the exterior part of wider cell, i.e., corresponding to cell edge UEs, based on the traffic demands, the network node 12 may trigger RACH-less handover to move a specific set of UEs from wider cell mapping of the beam to the narrower one. This may improve the link signal to noise ratio (SNR) and hence the throughput.

[0130] Beam hopping scheme with cells with narrow beam footprints combined with passive cells with wide beam footprints for initial cell selection for legacy UEs.

[0131] In one embodiment, there are two layers of cells on the same frequency. The first layer may have cells with wide beam footprints, each with an SSB with periodicity of 20 msec. The second layer may have cells with narrow beam footprints, each with an SSB with periodicity larger than 20 msec. The two cell layers may cover the same geographical area such that each cell with a wide beam footprint covers the same area as a number of cells with narrow beam footprint. The cells with narrow and wide beam footprints may be jointly beam hopping.

[0132] The cells with wide beam footprints may carry SSB and a minimum set of SIB. The SIB may configure cell reselection parameters that make the UEs perform cell reselection to cells with narrow beam footprints. The purpose of the cells with wide beam footprints may be to support initial cell selection for legacy UEs that assume SSB periodicity of 20 ms.

[0133] In one dependent embodiment, the cells with wide beam footprints are downlink only, such as passive cells. After camping on a cell with wide beam footprint, a UE 10 may perform cell reselection to a cell with narrow beam footprint before registering in the network.

[0134] In one dependent embodiment, the cells with wide beam footprints may be barred for non-legacy UE with a new barring flag.

[0135] The cells with narrow beam footprints may carry SSB, control channels and traffic for legacy UEs and non-legacy UEs.

[0136] In one embodiment, one or more of the solutions in previous sections may be applicable in a non-terrestrial satellite communication network based on an NR system, where the scheduler in a network node 12 such as e.g., gNodeB instructs a given satellite to turn-ON a first group of one or more beams illuminating a group of one or more cells among a plurality of beams and cells composing other groups that remained turned-OFF within the satellite’s footprint, resembling a beam hopping scheme since only one group of beams and cells are turned-ON at a time within the satellite’s footprint; wherein the group of one or more beams prevail illuminating a group of one or more cells at least until a set of downlink physical channels and signals having timing interrelations and / or codependencies have been transmitted, afterwards a beam hopping is performed turning- ON a second group of one or more beams illuminating a second group of one or more cells, and successively across all the groups of beams and cells within the satellite’s footprint.

[0137] In one embodiment, PBCH of punctured SSB may use power boosting to improve decoding performance.

[0138] In one embodiment, punctured SSB may be indicated by the network node 12 explicitly or implicitly. The network node 12may configure Energy per resource element (EPRE) offset between secondary synchronization signal (SSS) resource element (RE) and PBCH demodulation reference signal (DM RS) to X dB, then the UE 10 may decode SSB as punctured pattern.

[0139] In one embodiment, one or more of the solutions in previous sections may be applicable when one or more of the downlink coverage enhancements techniques are combined, e.g., Beam Hopping, Satellite beam width or Frequency Re-use and Satellite beam width.

[0140] In one embodiment, for any of the solutions presented in previous sections, a punctured SSB may be replaced by a regular SSB spanning 20-PRBs in the frequencydomain and 4 symbols in the time-domain as long as there is enough bandwidth available for it to be transmitted, which depends on the transmission bandwidth and the location of the synchronization raster point within of a given channel bandwidth.

[0141] In one embodiment, if the periodicity of one or more non-punctured SSBs, punctured SSB or non-cell defining SSB is increased, then the periodicity of the MIB TTI may also be increased.

[0142] In one embodiment, one or more of the solutions in previous sections may use in addition to a 12-PRB punctured SSB, also use 15-PRB and / or 20-PRB punctured CORESET#0 and / or the new 12-PRB CORESET#0 size.

[0143] In one embodiment, one or more of the solutions in previous sections may be utilized along with either, a unique cell utilizing one or more SSB indices or a plurality of cells each associated to only one SSB index among the available SSB indices.

[0144] In one embodiment, one or more of the solutions in previous sections may be utilized along asymmetric channel bandwidth.

[0145] In one embodiment, one or more of the embodiments in previous sections may be used in an NTN deployment using one beam per cell. In one embodiment, one or more of the embodiments in previous sections may be used in an NTN deployment using more than one beam per cell.

[0146] In one embodiment, an NTN NR UE may also encompass a reduced capability UE also known as reduce capability (RedCap) or eRedCap supporting non-terrestrial communications.

[0147] In one embodiment, one or more of the embodiments in previous sections may be equally applicable to a non-terrestrial network scenario based on transparent payload or regenerative payload.

[0148] In one embodiment, one or more of the embodiments in previous sections may be equally applicable to different satellite orbits such as Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Equatorial Orbit (GEO).

[0149] Fig. 12a shows a schematic flowchart according to some embodiments herein illustrating respective method performed by the network node 12 for handling synchronization indications in the wireless communication network. Also, a method perform by the UE 10 for handling synchronization indications in the wireless communication network is shown.

[0150] Action 1200. The network node 12 transmits the first synchronization indication and the second synchronization indication, towards the UE 10. The first synchronization indication is of the first type transmitted with the first periodicity at the first synchronization raster point, and the second synchronization indication is of the second type transmitted with the second periodicity, being longer than the first periodicity, at the second synchronization raster point. The first synchronization raster point may be different than the second synchronization raster point. The first type may be the non-punctured SSB or a NCD SSB, and the second type may be the punctured SSB, or a, CD, -SSB. The punctured SSB may encompass 12-PRBs, in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB may encompass 20-PRBs in the frequencydomain and 4 symbols in the time-domain. The second periodicity may be any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and the first periodicity may be 20 ms. The first synchronization indication may be transmitted with the first periodicity during initial cell selection and once the UE is in connected-mode, the first synchronization indication may be transmitted with the second periodicity. The second synchronization indication may be transmitted with the second periodicity at the same synchronization raster point and a different time instance as the first synchronization indication. The first synchronization indication and the second synchronization indication may be transmitted in one or more beam footprints configured to serve or cover the UE 10. The wireless communication network may comprise an NTN. The first and second synchronization indications may comprise a respective SSB. The first synchronization indication and the second synchronization indication may be transmitted towards the UE 10 during initial cell selection. The first synchronization indication may be transmitted in a wider beam of a first frequency range and the second synchronization indication may be transmitted in a narrower beam in a second frequency range.

[0151] Action 1201. From the UEs point of view: The UE 10 receives a synchronization indication being one out of the first synchronization indication and the second synchronization indication, wherein the first synchronization indication is of the first type transmitted with the first periodicity at the first synchronization raster point, and the second synchronization indication is of the second type transmitted with the second periodicity, being longer than the first periodicity, at the second synchronization raster point. The first synchronization raster point may be different than the second synchronization raster point. The first type may be a non-punctured SSB or a NCD-SSB, and the second type may be a punctured SSB or a CD-SSB. The punctured SSB may encompass 12-PRBs, in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB may encompass 20-PRBs in the frequency-domain and 4 symbols in the time-domain. The second periodicity may be any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and wherein the first periodicity may be 20 ms. The first synchronization indication may be received with the first periodicity during initial cell selection and once the UE is in connected-mode, the first synchronization indication may be received with the second periodicity. The first synchronization indication and the second synchronization indication may be received in one or more beam footprints configured to serve or cover the UE 10. The wireless communication network may comprise an NTN. The first and second synchronization indications may comprise a respective SSB. As an example, a set of sync-raster points spanning across a band, odd sync-raster points may be associated with 20 ms SSB periodicity, and even sync-raster points may be associated with 160 ms SSB periodicity, from this pre-knowledge, UE implementations may optimize and e.g., search only for even sync-raster points.

[0152] The UE 10 may receive from network node 12, one or more synchronization indications, such as SSBs, in one or more beam footprints configured to serve or cover the UE 10. The UE 10 may receive one or more SSBs in a first beam footprint, wherein the first beam footprint covers, at least partly, two or more second beam footprints. As an example, the UE 10 may receive one or more synchronization indications such as SSBs from the network node 12 over a wider beam footprint generated by the network node 12, wherein the wider beam footprint covers two or more narrower beam footprints.

[0153] Action 1202. The UE may perform initial cell selection based on the received synchronization indication. The UE 10 may then communicate data and / or SSBs with the network node 12.

[0154] Fig. 12b shows a schematic flowchart according to some embodiments herein illustrating a respective method performed by the network node 12 and the UE 10.

[0155] Action 121. The network node 12 may initiate the communication, towards the UE 10, of one or more synchronization indication, such as SSBs, in one or more beam footprints configured to serve or cover the UE 10.

[0156] Action 1211. The network node 12 may transmit one or more SSBs in the first beam footprint, wherein the first beam footprint covers, at least partly, two or more second beam footprints. As an example, the network node 12 may transmit one or more synchronization indications such as SSBs towards the UE 10 the wider footprint or spot beam generated by the network node, wherein the wider footprint or spot beam covers two or more narrower footprints or spot beams.

[0157] Action 1212. The network node 12 may further communicate data and / or one or more SSBs with the UE 10, over one or more second beam footprints and / or the first beam footprint. The network node 12 and the UE 10 may then communicate other data and / or SSB over a narrower footprint or spot beam and / or the wider footprint or spot beam.

[0158] Action 1213. The network node 12 may transmit the first synchronization indication and the second synchronization indication towards the UE 10, in one or more footprint or spot beams configured to serve or cover the UE 10. The first synchronization indication is of the first type and the second synchronization indication is of the second type. The first type may be a punctured SSB and the second type may be a non-punctured SSB. Thus, the network node 12 may perform a dual transmission, transmissions in parallel or simultaneous transmission of the first and second type of synchronization indications. It should be noted that the network node 12 may transmit the first synchronization indication in the narrower beam footprint and / or the wider beam footprint, and the network node 12 may transmit the second synchronization indication in another or same narrower beam footprint and / or the wider beam footprint. As an example, the network node 12 may transmit one or more physical channels and signals, such as SSB, SIB1, SIB19, in a beam footprint that is wider in size than one or more other beam footprints that are narrower in size and that are transmitted each at different time instances. The SIB1 may comprise information of PRACH occasions associated with a narrow beam footprint, and / or SIB1 or SIB19 may comprise information of reference locations corresponding to the geographical centers of the narrow beam footprints.

[0159] Action 122. Thus, the UE 10 may receive from network node 12, such as a satellitebased access node, one or more synchronization indications, such as SSBs, in one or more beam footprints configured to serve or cover the UE 10. The UE 10 may receive one or more SSBs in a first beam footprint, wherein the first beam footprint covers, at least partly, two or more second beam footprints. As an example, the UE 10 may receive one or more synchronization indications such as SSBs from the network node 12 over a wider beam footprint generated by the network node 12, wherein the wider beam footprint covers two or more narrower beam footprints.

[0160] Action 123. The UE 10 may then communicate data and / or one or more SSBs with the network node 12 over one or more second beam footprints and / or the first beam footprint. The UE 10 may communicate i.e. , receive and / or transmit other data and / or SSB over a narrower beam footprint and / or the wider beam footprint.

[0161] As an example, the UE 10 receives from the network node 12, such as a satellite based access node, one or more physical channels and signals, such as SSB, SIB1, SIB19, in a beam footprint that is wider in size than one or more other beam footprints that are narrower in size and that are transmitted each at different time instances. The SIB1 may comprise information of PRACH occasions associated to each narrow beam footprint and SIB1 or SIB19 may comprise information of reference locations corresponding to the geographical centers of the narrow beam footprints, furthermore, the UE 10 may determine its distance to reference locations to know the closest narrow beam footprint and after identifying the most suitable one, such as best signal strength or quality, the UE 10 may trigger PRACH transmission on the corresponding RACH occasion, and thereafter continue receiving subsequent physical channels and signals such as data traffic channels.

[0162] As another example, the UE 10 receives from the network node 12, such as a satellite based access node, one or more physical channels and signals such as SSB, SIB1 in one or more beam footprints that is wider in size than one or more other beam footprints, that are narrower in size, and that are transmitted each at different time instances. The SIB1 may comprise information of PRACH occasions associated to a narrow beam footprint, and wherein the UE 10 may receive one or more CSI-RSs on one or more narrow beam footprints and after identifying the most suitable one i.e., best signal strength or quality, the UE 10 may trigger PRACH transmission on a corresponding RACH occasion, and thereafter continue receiving subsequent physical channels and signals such as data traffic channels.

[0163] Embodiments herein may possibly incorporate that the UE 10 may assume SSB periodicities longer than 20 ms during initial cell selection. A punctured SSB may be used for the downlink coverage enhancements feature that in turn makes use of e.g., Beam Hopping, Satellite beam width or Frequency Re-use and Satellite beam width.

[0164] Fig. 13 is a block diagram depicting the network node 12, such as the satellite based access node or SAN, for handling communication e.g., synchronization indications in the wireless communication network e.g., NTN according to embodiments herein.

[0165] The network node 12 may comprise processing circuitry 1301 , e.g. one or more processors, configured to perform the methods herein.

[0166] The network node 12 and / or the processing circuitry 1301 is configured to transmit the first synchronization indication and the second synchronization indication, towards the UE 10. The first synchronization indication is of the first type transmitted with the first periodicity at the first synchronization raster point, and the second synchronization indication is of the second type transmitted with the second periodicity, being longer than the first periodicity, at the second synchronization raster point. The first synchronization raster point may be different than the second synchronization raster point.

[0167] The first type may be a non-punctured PBCH block and the second type may be a punctured SSB or a CD-SSB. The punctured SSB may encompass 12- PRB in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB may encompass 20-PRBs in the frequency-domain and 4 symbols in the time-domain. The second periodicity may be any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and wherein the first periodicity may be 20 ms. The first synchronization indication may be transmitted with the first periodicity during initial cell selection and once the UE 10 is in connected-mode, the first synchronization indication may be transmitted with the second periodicity. The second synchronization indication may be transmitted with the second periodicity at a same synchronization raster point and a different time instance as the first synchronization indication. The first and second synchronization indications may comprise a respective synchronization signal and PBCH block. The first synchronization indication and the second synchronization indication may be transmitted towards the UE 10 during initial cell selection. The first synchronization indication may be transmitted in a wider beam of a first frequency range and the second synchronization indication may be transmitted in a narrower beam in a second frequency range.

[0168] The network node 12 and / or the processing circuitry 1301 may be configured to perform initial cell selection based on the received synchronization indication. The network node 12 and / or the processing circuitry 1301 may be configured to initiate the communication, towards the UE 10, of one or more synchronization indication, such as SSBs, in one or more beam footprints configured to serve or cover the UE 10.

[0169] The network node 12 and / or the processing circuitry 1301 may be configured to transmit one or more SSBs in the first beam footprint, wherein the first beam footprint covers, at least partly, two or more second beam footprints. As an example, the network node 12 and / or the processing circuitry 1301 may be configured to transmit one or more synchronization indications such as SSBs towards the UE the wider footprint or spot beam generated by the network node, wherein the wider footprint or spot beam covers two or more narrower footprints or spot beams.

[0170] The network node 12 and / or the processing circuitry 1301 may be configured to communicate data and / or one or more SSBs with the UE 10, over one or more second beam footprints and / or the first beam footprint. The network node 12 and / or the processing circuitry 1301 may be configured to communicate other data and / or SSB over a narrower footprint or spot beam and / or the wider footprint or spot beam.

[0171] The network node 12 and / or the processing circuitry 1301 may be configured to transmit the first synchronization indication and the second synchronization indication towards a UE, in one or more footprint or spot beams configured to serve or cover the UE. The first synchronization indication is of the first type and the second synchronization indication is of the second type. The first type may be a punctured SSB and the second type may be a non-punctured SSB. Thus, the network node 12 and / or the processing circuitry 1301 may be configured to perform a dual transmission, transmissions in parallel or simultaneous transmission of the first and second type of synchronization indications. It should be noted that the network node 12 and / or the processing circuitry 1301 may be configured to transmit the first synchronization indication in the narrower beam footprint and / or the wider beam footprint, and the network node 12 and / or the processing circuitry 1301 may be configured to transmit the second synchronization indication in another or same narrower beam footprint and / or the wider beam footprint. The network node 12 may comprise a memory 1305. The memory 1305 comprises one or more units to be used to store data on, such as data packets, indications, beam footprint parameters, SSBs, support information, events and applications to perform the methods disclosed herein when being executed, and similar. Furthermore, the network node 12 may comprise a communication interface 1306 such as comprising a transmitter, a receiver, a transceiver and / or one or more antennas.

[0172] The methods according to the embodiments described herein for the network node 12 are respectively implemented by means of e.g. a computer program product 1307 or a computer program, comprising instructions, i.e. , software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the network node 12. The computer program product 1307 may be stored on a computer-readable storage medium 1308, e g., a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium 1308, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the network node 12. In some embodiments, the computer-readable storage medium 1308 may be a transitory or a non-transitory computer-readable storage medium. Thus, embodiments herein may disclose the network node 12 for handling communication in a wireless communication network such as an NTN, wherein the network node 12 comprises processing circuitry 1301 and a memory 1305, said memory 1305 comprising instructions executable by said processing circuitry 1301 whereby said network node 12 is operative to perform any of the methods herein.

[0173] Fig. 14 is a block diagram depicting the UE 10 for handling communication e.g., synchronization indications in the wireless communication network 1 according to embodiments herein.

[0174] The UE 10 may comprise processing circuitry 1401 , e.g. one or more processors, configured to perform the methods herein.

[0175] The UE 10 and / or the processing circuitry 1401 is configured to receive from the network node 12, such as a satellite based access node, a synchronization indication, such as SSBs, being one out of a first synchronization indication and a second synchronization indication. The first synchronization indication is of the first type transmitted with the first periodicity at the first synchronization raster point, and the second synchronization indication is of the second type transmitted with the second periodicity, being longer than the first periodicity, at the second synchronization raster point. The UE 10 and / or the processing circuitry 1401 may be configured to receive in one or more beam footprints configured to serve or cover the UE. The UE 10 and / or the processing circuitry 1401 may be configured to receive one or more SSBs in a first beam footprint, wherein the first beam footprint covers, at least partly, two or more second beam footprints. As an example, the UE 10 and / or the processing circuitry 1401 may be configured to receive one or more synchronization indications such as SSBs from the network node 12 over a wider beam footprint generated by the network node, wherein the wider beam footprint covers two or more narrower beam footprints. The first synchronization raster point may be different than the second synchronization raster point. The first type may be a non-punctured PBCH block SSB and the second type may be a punctured SSB or a CD-SSB. The punctured SSB may encompass 12-PRBs in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB may encompass 20-PRBs in the frequency-domain and 4 symbols in the time-domain. The second periodicity may be any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and wherein the first periodicity may be 20 ms. The first synchronization indication may be received with the first periodicity during initial cell selection and once the UE 10 is in connected-mode, the first synchronization indication may be received with the second periodicity. The first synchronization indication and the second synchronization indication may be received in one or more beam footprints configured to serve or cover the UE 10. The wireless communication network may comprise a non terrestrial network. The first and second synchronization indications may comprise a respective synchronization signal and PBCH block.

[0176] The UE 10 and / or the processing circuitry 1401 may be configured to communicate data and / or one or more SSBs with the network node 12 over one or more second beam footprints and / or the first beam footprint. The UE 10 and / or the processing circuitry 1401 may be configured to communicate i.e. , receive and / or transmit other data and / or SSB over a narrower beam footprint and / or the wider beam footprint.

[0177] The UE 10 may comprise a memory 1405. The memory 1405 comprises one or more units to be used to store data on, such as data packets, indications, measurements, configurations, SSBs, support information, events and applications to perform the methods disclosed herein when being executed, and similar. Furthermore, the UE 10 may comprise a communication interface 1406 such as comprising a transmitter, a receiver, a transceiver and / or one or more antennas. The methods according to the embodiments described herein for UE 10 are respectively implemented by means of e.g. a computer program product 1407 or a computer program, comprising instructions, i.e. , software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE 10. The computer program product 1407 may be stored on a computer-readable storage medium 1408, e g., a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium 1408, having stored thereon the computer program product 1407, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE 10. In some embodiments, the computer-readable storage medium 1408 may be a transitory or a non-transitory computer-readable storage medium. Thus, embodiments herein may disclose the UE 10 for handling communication e.g., synchronization indications in the wireless communication network e.g., NTN, wherein the UE 10 comprises processing circuitry 1401 and a memory 1405, said memory 1405 comprising instructions executable by said processing circuitry 1401 whereby said UE 10 is operative to perform any of the methods herein.

[0178] In some embodiments a more general term “network node” is used and it can correspond to any type of radio-network node or any network node, which communicates with a UE and / or with another network node.

[0179] In some embodiments the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and / or with another wireless device in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, proximity capable UE (aka ProSe UE), loT capable device, machine type UE or UE capable of machine to machine (M2M) communication, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles etc.

[0180] Embodiments are applicable to any RAT or multi-RAT systems, where the wireless device receives and / or transmit signals (e.g. data) e.g. NR, Wi-Fi, LTE, LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications / enhanced Data rate for GSM Evolution (GSM / EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. Fig. 15 shows an example of a communication system 15100 in accordance with some embodiments.

[0181] In the example, the communication system 15100 includes a telecommunication network 15102 that includes an access network 15104, such as a radio access network (RAN), and a core network 15106, which includes one or more core network nodes 15108 such as the first network node 140. The access network 15104 includes one or more access network nodes, such as network nodes 15110a and 15110b (one or more of which may be generally referred to as network nodes 15110, or radio network node 130), or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 15102 includes one or more Open- RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 15102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 15102, including one or more network nodes 15110, being examples of the network node 12, and / or core network nodes 15108.

[0182] Examples of an ORAN network node include an open radio unit (0-Rll), an open distributed unit (0-Dll), an open central unit (O-CU), including an O-CU control plane (O- CLI-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1, F1, W1, E1 , E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 15110, such as the network node 12, facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 15112a, 15112b, 15112c, and 15112d (one or more of which may be generally referred to as UEs 15112 or UE 10) to the core network 15106 over one or more wireless connections.

[0183] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 15100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 15100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0184] The UEs 15112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 15110 and other communication devices. Similarly, the network nodes 15110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 15112 and / or with other network nodes or equipment in the telecommunication network 15102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 15102.

[0185] In the depicted example, the core network 15106 connects the network nodes 15110 to one or more host computing systems, such as host 15116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 15106 includes one more core network nodes (e.g., core network node 15108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 15108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0186] The host 15116 may be under the ownership or control of a service provider other than an operator or provider of the access network 15104 and / or the telecommunication network 15102. The host 15116 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0187] As a whole, the communication system 15100 of Figure 15 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0188] In some examples, the telecommunication network 15102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 15102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 15102. For example, the telecommunications network 15102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0189] In some examples, the UEs 15112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 15104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 15104. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved- UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0190] In the example, the hub 15114 communicates with the access network 15104 to facilitate indirect communication between one or more UEs (e.g., UE 15112c and / or 15112d) and network nodes (e.g., network node 15110b). In some examples, the hub 15114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 15114 may be a broadband router enabling access to the core network 15106 for the UEs. As another example, the hub 15114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 15110, or by executable code, script, process, or other instructions in the hub 15114. As another example, the hub 15114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 15114 may be a content source. For example, for a UE that is a VR device, display, loudspeaker, or other media delivery device, the hub 15114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 15114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 15114 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0191] The hub 15114 may have a constant / persistent or intermittent connection to the network node 15110b. The hub 15114 may also allow for a different communication scheme and / or schedule between the hub 15114 and UEs (e.g., UE 15112c and / or 15112d), and between the hub 15114 and the core network 15106. In other examples, the hub 15114 is connected to the core network 15106 and / or one or more UEs via a wired connection. Moreover, the hub 15114 may be configured to connect to an M2M service provider over the access network 15104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 15110 while still connected via the hub 15114 via a wired or wireless connection. In some embodiments, the hub 15114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 15110b. In other embodiments, the hub 15114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 15110b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0192] Fig. 16 shows a UE 15300 in accordance with some embodiments. The UE 15300 presents additional details of some embodiments of the UE 15112 of Figure 15. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage / playback device, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), an Augmented Reality (AR) or Virtual Reality (VR) device, wireless customer-premise equipment (CPE), vehicle, vehiclemounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-loT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0193] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0194] The UE 15300 includes processing circuitry 15302 that is operatively coupled via a bus 15304 to an input / output interface 15306, a power source 15308, a memory 15310, a communication interface 15312, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Fig. 16. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc. The processing circuitry 15302 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 15310. The processing circuitry 15302 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 15302 may include multiple central processing units (CPUs).

[0195] In the example, the input / output interface 15306 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 15300. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0196] In some embodiments, the power source 15308 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 15308 may further include power circuitry for delivering power from the power source 15308 itself, and / or an external power source, to the various parts of the UE 15300 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 15308. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 15308 to make the power suitable for the respective components of the UE 15300 to which power is supplied. The memory 15310 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 15310 includes one or more application programs 15314, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 15316. The memory 15310 may store, for use by the UE 15300, any of a variety of various operating systems or combinations of operating systems.

[0197] The memory 15310 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUlCC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 15310 may allow the UE 15300 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 15310, which may be or comprise a device-readable storage medium.

[0198] The processing circuitry 15302 may be configured to communicate with an access network or other network using the communication interface 15312. The communication interface 15312 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 15322. The communication interface 15312 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 15318 and / or a receiver 15320 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 15318 and receiver 15320 may be coupled to one or more antennas (e.g., antenna 15322) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0199] In the illustrated embodiment, communication functions of the communication interface 15312 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0200] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 15312, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0201] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0202] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 15300 shown in Fig. 16.

[0203] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-loT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0204] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0205] Fig. 17 shows a network node 15400 in accordance with some embodiments, such as the network node 12. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU). Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0206] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi- cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0207] The network node 15400 includes a processing circuitry 15402, a memory 15404, a communication interface 15406, and a power source 15408. The network node 15400 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 15400 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 15400 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 15404 for different RATs) and some components may be reused (e.g., a same antenna 15410 may be shared by different RATs). The network node 15400 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 15400, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 15400.

[0208] The processing circuitry 15402 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 15400 components, such as the memory 15404, to provide network node 15400 functionality.

[0209] In some embodiments, the processing circuitry 15402 includes a system on a chip (SOC). In some embodiments, the processing circuitry 15402 includes one or more of radio frequency (RF) transceiver circuitry 15412 and baseband processing circuitry 15414. In some embodiments, the RF transceiver circuitry 15412 and the baseband processing circuitry 15414 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 15412 and baseband processing circuitry 15414 may be on the same chip or set of chips, boards, or units.

[0210] The memory 15404 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device- readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 15402. The memory 15404 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 15402 and utilized by the network node 15400. The memory 15404 may be used to store any calculations made by the processing circuitry 15402 and / or any data received via the communication interface 15406. In some embodiments, the processing circuitry 15402 and memory 15404 is integrated.

[0211] The communication interface 15406 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 15406 comprises port(s) / terminal(s) 15416 to send and receive data, for example to and from a network over a wired connection. The communication interface 15406 also includes radio front-end circuitry 15418 that may be coupled to, or in certain embodiments a part of, the antenna 15410. Radio front-end circuitry 15418 comprises filters 15420 and amplifiers 15422. The radio front-end circuitry 15418 may be connected to an antenna 15410 and processing circuitry 15402. The radio front-end circuitry may be configured to condition signals communicated between antenna 15410 and processing circuitry 15402. The radio front-end circuitry 15418 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 15418 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 15420 and / or amplifiers 15422. The radio signal may then be transmitted via the antenna 15410. Similarly, when receiving data, the antenna 15410 may collect radio signals which are then converted into digital data by the radio front-end circuitry 15418. The digital data may be passed to the processing circuitry 15402. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0212] In certain alternative embodiments, the network node 15400 does not include separate radio front-end circuitry 15418, instead, the processing circuitry 15402 includes radio front-end circuitry and is connected to the antenna 15410. Similarly, in some embodiments, all or some of the RF transceiver circuitry 15412 is part of the communication interface 15406. In still other embodiments, the communication interface 15406 includes one or more ports or terminals 15416, the radio front-end circuitry 15418, and the RF transceiver circuitry 15412, as part of a radio unit (not shown), and the communication interface 15406 communicates with the baseband processing circuitry 15414, which is part of a digital unit (not shown).

[0213] The antenna 15410 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 15410 may be coupled to the radio front-end circuitry 15418 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 15410 is separate from the network node 15400 and connectable to the network node 15400 through an interface or port.

[0214] The antenna 15410, communication interface 15406, and / or the processing circuitry 15402 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 15410, the communication interface 15406, and / or the processing circuitry 15402 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0215] The power source 15408 provides power to the various components of network node 15400 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 15408 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 15400 with power for performing the functionality described herein. For example, the network node 15400 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 15408. As a further example, the power source 15408 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0216] Embodiments of the network node 15400 may include additional components beyond those shown in Fig. 17 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 15400 may include user interface equipment to allow input of information into the network node 15400 and to allow output of information from the network node 15400. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 15400. In some embodiments providing a core network node, such as core network node 15108 of Fig. 15, some components, such as the radio front-end circuitry 15418 and the RF transceiver circuitry 15412 may be omitted.

[0217] Fig. 18 is a block diagram illustrating a virtualization environment 15500 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 15500 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 15500 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface. Virtualization may facilitate distributed implementations of a network node, UE, core network node, or host.

[0218] Applications 15502 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q500 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0219] Hardware 15504 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 15506 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 15508a and 15508b (one or more of which may be generally referred to as VMs 15508), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 15506 may present a virtual operating platform that appears like networking hardware to the VMs 15508.

[0220] The VMs 15508 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 15506. Different embodiments of the instance of a virtual appliance 15502 may be implemented on one or more of VMs 15508, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0221] In the context of NFV, a VM 15508 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, nonvirtualized machine. Each of the VMs 15508, and that part of hardware 15504 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 15508 on top of the hardware 15504 and corresponds to the application 15502.

[0222] Hardware 15504 may be implemented in a standalone network node with generic or specific components. Hardware 15504 may implement some functions via virtualization. Alternatively, hardware 15504 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 15510, which, among others, oversees lifecycle management of applications 15502. In some embodiments, hardware 15504 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 15512 which may alternatively be used for communication between hardware nodes and radio units.

[0223] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0224] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0225] In some embodiments a more general term “network node” is used and it can correspond to any type of radio network node or any network node, which communicates with a wireless device and / or with another network node. Examples of network nodes are NodeB, Master eNB, Secondary eNB, a network node belonging to Master cell group (MCG) or Secondary Cell Group (SCG), base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), core network node e.g. Mobility Switching Center (MSC), Mobile Management Entity (MME) etc., Operation and Maintenance (O&M), Operation Support System (OSS), SelfOrganizing Network (SON), positioning node e.g. Evolved Serving Mobile Location Center (E-SMLC), Minimizing Drive Test (MDT), etc.

[0226] In some embodiments, the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and / or with another UE in a cellular or mobile communication system. Examples of UE are target device, device-to-device (D2D) UE, proximity capable UE (aka ProSe UE), machine type UE or UE capable of machine to machine (M2M) communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles etc. The embodiments are described for 5G. However the embodiments are applicable to any RAT or multi-RAT systems, where the UE receives and / or transmit signals (e.g. data) e.g. LTE, LTE frequency division duplex (FDD) / time division duplex (TDD), WCDMA / HSPA, GSM / GERAN, Wi Fi, WLAN, CDMA2000 etc.

[0227] As will be readily understood by those familiar with communications design, functions means or modules may be implemented using digital logic and / or one or more microcontrollers, microprocessors, or other digital hardware. In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and / or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a wireless device or network node, for example.

[0228] Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term “processor” or “controller” as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random-access memory for storing software and / or program or application data, and non-volatile memory. Other hardware, conventional and / or custom, may also be included. Designers of communications devices will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices.

[0229] It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents. ANNEX:

[0230] • Introduction

[0231] The first objective of the WID entitled “Non-Terrestrial Networks (NTN) for NR Phase 3” describes the scope of downlink coverage enhancements [1]. RAN1 made multiple agreements related to this objective during the previous meetings [2] - [5]. According to the WID, RAN1 should report on impact to backward compatibility, if any, for potential extension of the SSB periodicity at the latest by RAN#106, in conjunction with the targeted system-level enhancements [1], which are discussed in the following.

[0232] • SSB periodicity extension and its impact

[0233] As mentioned in Section 1 , the revised WID [1] considers the SSB periodicity extension. Therefore, it is now essential to investigate to what extent SSB periodicity can be increased beyond the default value of 20 ms during cell search. As mentioned in Section 2.1 , the values to be considered for the study of SSB periodicity extension are one [or more] values from the list {40ms, 80 ms, 160 ms, 320ms, 640ms}. Currently, 5G NR supports the following:

[0234] According to Section 4.1 , TS 38.213, for initial cell selection, a UE may assume that half frames with SS / PBCH blocks occur with a periodicity of 2 frames [5], Thus, the UE assumes a periodicity of 20 ms for SSB during cell search.

[0235] Given that there is no information during the first step of cell search, the UE assumes the default value of 20 ms for SSB periodicity. Therefore, if the SSB is transmitted with 20 ms periodicity, the UEs prior to release-19 operate without any issue. However, if the SSB is transmitted with a periodicity larger than 20 ms, then the UEs prior to release-19 lack this information and still perform cell search as if the SSB is transmitted with 20 ms periodicity, which could affect its initial access and connection establishment. On the other hand, release-19+ UEs may not have such issue. Altogether, there is a backward compatibility issue for prior to release-19 UEs due to the extension of SSB periodicity.

[0236] Next, if the SSB periodicity for initial cell selection is extended, then it is important to discuss up to what value it is desirable and feasible to extend without incurring in significant specification impacts. In addition to cell search, the periodicity of SSB is also relevant in rate matching and measurement timing configurations, etc. Unlike in cell search, where the UE lacks any information before the decoding of SSB, the UE is explicitly informed about the SSB periodicity in these cases as follows:

[0237] • The SSB periodicity in ms indicated in the information element ssb-periodicityServingCell is used for the rate matching purpose, which can be either 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms. If the field is absent, the UE assumes a periodicity of 5 ms.

[0238] • In the context of neighbour cell, SSB-MTC is used to configure measurement timing configurations, i.e., timing occasions at which the UE measures SSBs. The periodicity can be either 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms.

[0239] Additionally, there exist RAN4 UE transmit timing requirements in Section 7.1 C.2 of TS 38.133. According to this:

[0240] • The UE initial transmission timing error shall be less than or equal to ±T6NTN where the timing error limit value Te NTNis specified in Table 7.1 C.2-1.

[0241] • The UE shall meet the TeNTNrequirement for an initial transmission provided that at least one SSB is available at the UE during the last 160 ms. Note that the maximum value for the SSB periodicity in the existing specification is 160 ms for different purposes as explained above. Therefore, if the SSB periodicity were to be extended beyond 20 ms, it is beneficial in terms of the specification efforts to consider the SSB period to be at most 160 ms for initial cell selection, but not larger values such as 320 ms and 640 ms. The maximum value for the SSB periodicity in the existing specifications is 160 ms for different purposes such as rate matching and measurement timing configuration. Whereas for cell search (i.e., initial cell selection), the maximum value for the SSB periodicity in the existing specification is 20 ms. The extension of SSB periodicity beyond 20 ms for cell search operation leads to backward compatibility issue for prior to release-19 UEs.

[0242] If the SSB periodicity is extended beyond 20 ms for cell search operation, it is beneficial to consider it to be at most 160 ms to limit the specification impact.

[0243] RAN1 to consider the maximum value of 160 ms while considering the extension of SSB periodicity beyond 20 ms for cell search operation.

[0244] It is also important to evaluate the impact of SSB periodicity extension on the legacy UEs, for which we consider two cases with link-level simulation settings as in TABLE 1 .

[0245] 1) SSB periodicity 20 ms, 4 combinations of PBCH are utilized to decode the MIB,

[0246] 2) SSB periodicity of 160 ms, single-shot detection of MIB. Tablel . Assumptions for SSB simulations.

[0247] Table 2. Link-level evaluation of SSB, including the required SNR to meet the target BLER as well as the gap with respect to CNR. It is observed in simulations that the required SNR to meet the BLER target is about -11 .3 dB and -

[0248] 6.3 dB, for cases: 1) SSB periodicity 20 ms, 4 combinations of PBCH are utilized to decode the MIB, 2) SSB periodicity of 160 ms, single-shot detection of MIB, respectively, under the assumption that UE is aware of the SSB periodicity. The corresponding coverage margin is about -9.4 dB and -4.4 dB, respectively, for case 1) and case 2), with respect to CNR of -1.9 dB of Set 1-1 / 1-2 FR1. On the other hand, with respect to CNR of - 8 dB of Set 1-3 FR1 , there exist coverage margin of -3.3 dB for case 1) and coverage gap of 1.7 dB for case 2), which are summarized in table 2. However, in practice and based on TS 38.213 clause 4.1 , the legacy UE expects the SSB periodicity to be transmitted using a 20 ms SSB periodicity, thus there is no performance guarantee since the SSB may or may not be decoded and if decoded (which is implementation dependent) the expected performance would be inferior to mentioned above during initial cell selection. This, in turn affects the cell search complexity as well as latency and success rate during initial cell selection of the legacy UEs. Therefore, if we consider a scenario with the legacy UEs attempting to camp in an NTN cell operating with 160 ms SSB, the legacy UE may or may not be able to detect the SSB depending on whether the observation interval overlaps with the time instant corresponding to the actual SSB transmission.

[0249] If the SSB periodicity is extended beyond 20 ms, the legacy UE may or may not be able to detect the SSB depending on whether the received signal observation interval overlaps with the time instant corresponding to the actual SSB transmission. This, in turn affects the cell search complexity as well as latency and success rate during initial cell selection of the legacy UEs.

[0250] If the beam hopping is implemented at the network-level, it is up to the gNB to schedule either the downlink or the uplink channels / signals in any cell that is being active via a specific illuminated satellite beam. Moreover, depending on whether the UE is performing cell search or the UE is in the phase of data transmission, there exists uplink communication following the downlink communication. For instance, the UE is expected to initiate the random access in the uplink after successfully receiving the SSB and SIB1 / SIB19 in the downlink, for which the gNB needs to facilitate the uplink resources. Similarly, the UE is expected to provide the HARQ feedback in the uplink after receiving the PDSCH in the downlink. Therefore, it is essential to consider the network operation both in terms of DL and UL while devising the beam hopping. Specifically, if the SSB periodicity is extended to a larger value than the default value of 20 ms, then it is essential to investigate its impact on the periodicity of the remaining mandatory physical channels and signals (e.g., SIB1 , SIB19, etc.) by considering the network operation both in terms of downlink and uplink.

[0251] Network operation cannot be viewed solely in terms of the downlink as the UE is expected to initiate uplink communication following the reception of certain downlink physical channels and signals.

[0252] RAN1 to investigate the impact of the periodicity of the remaining mandatory physical channels and signals (i.e., timelines of physical channels and signals) due to the extension of the SSB periodicity to a value larger than 20 ms for cell search operation.

[0253] RAN1 to consider the mandatory signals of both downlink and uplink at least while investigating the periodicities based on the extended SSB periodicity for cell search operation.

[0254] In practice, though it is desirable to have type of cells that operate with a single value of periodicity for SSB, it is necessary to have the support for larger values of SSB periodicity during cell search to facilitate the beam hopping. Specifically, if the SSB periodicity beyond 20 ms is supported, then it leads to the presence of scenarios: a) NTN cell operating with 20 ms SSB periodicity and b) NTN cell operating with 160 ms periodicity. Each scenario has different implications on the UE side and on the network side, which are discussed below.

[0255] RAN1 to focus on the beam hopping implemented with NTN cells operating with SSB periodicity of either 20 ms or 160 ms. • Beam hopping Schemes

[0256] In the following, we refer to the beam footprints corresponding to diameter of 50 km as a baseline or narrower beam footprint while beam footprint diameter larger than 50 km, e.g., 79 km, as wider beam footprint. Based on the previous RAN1 meeting discussions and captured observations, the following beam hopping schemes can be considered.

[0257] • Beam hopping for NTN cells operating with wider beam footprints and 20 ms SSB periodicity

[0258] • Beam hopping for NTN cells operating with narrower beam footprints and extended SSB periodicity

[0259] • Beam hopping for NTN cells operating with combination of wider and narrower beam footprints and extended SSB periodicity o Beam hopping for NTN cells operating with wider beam footprints and 20 ms SSB periodicity

[0260] The legacy UEs prior to rel-19 operate as usual. The Rel-19+UEs would have to hypothesize whether it is dealing with a 20 ms SSB periodicity or a longer SSB periodicity, under the assumption that via UE implementation it will eventually determine the actual SSB periodicity (and MIB periodicity).

[0261] In an NR NTN cell operating with SSB periodicity of 20 ms, the legacy UEs prior to rel-19 can operate as usual. On the other hand, the Rel-19+UEs would have to hypothesize whether it is dealing with a 20 ms SSB periodicity or a longer SSB periodicity.

[0262] For instance, consider Set 1-1. If a beam pattern consists of distinct 10% of beams which are activated each time instance to provide the coverage on the earth, then it requires total 10-time instances to cover the whole satellite footprint. After completing one such round, the first beam pattern gets its turn to serve again. The time involved between two instances of a beam in a specific beam pattern being active is called revisit time, Trevisit, which is limited by the timeline constraints imposed by the 5G NR mandatory common signals (e.g., SSB, SIB1 , SIB19, etc.) that facilitate the UE to access the network. For instance, the UEs in IDLE mode are expected to receive SSB once every 20 ms. If we base this as a revisit time interval, each beam in a beam pattern can only get 2 msec interval to be active, called dwell time, Tdwell. Such a short interval of dwell time will not be sufficient to meet the traffic demands in each cell illuminated by a beam. In contrast to the narrower beams, one can alter the way beams are mapped to the cells that is by mapping beam footprint to wider cell areas on the earth. Such a mapping allows to reduce the number of beam footprints required to cover the satellite coverage region and consequently reduces the number of cells over which beam is required to be hopped. Altogether, the dwell time available for each cell increases for a fixed revisit time interval for each beam illumination compared to that of narrower beams. In this case, beam hopping can potentially be implemented by using the default SSB periodicity of 20 ms yet providing the reasonable dwell time for each cell.

[0263] At this point, we recall the beam layout defined in Table 6.1.1.1-4 in TR 38.821 (cf. Annex A) to deduce the beam layout configuration that can be useful in the mapping of beam footprints to wider cells.

[0264] ■ Beam layout

[0265] According to the beam layout defined in Table 6.1.1 .1-4 in TR 38.821 (cf. Annex A) hexagonal mapping of the beam bore sight directions on UV plane are defined and based on the beam layout definition in UV plane and the satellite location, one can obtain the beam layout plot on earth by applying the right transfer functions. The straight line being orthogonal to UV plane is pointing towards the Earth centre and UV coordinates of the nadir of the reference satellite is (0,0). The 3-dB contour radius in UV plane ruv= sin 03dBwith 03dB= HPBW / 2. The baseline inter-beam distance or adjacent beam spacing (ABS) on UV plane is computed based on the 3-dB beam width of the satellite antenna pattern as

[0266] ABS = V3 x sin(0.5 x HPBW [rad]) (Eq. 1)

[0267] While the distance between adjacent beams is constant in the UV plane, this is not true in the X-Y- Z (3D cartesian) coordinate system. Short of going into further details, we refer to [9] or the details. The hexagonal cell area as function of r^ is ^r^v, which can be expressed in terms of ABS as

[0268] ABS2. If the ABS on UV plane is set to ABS = * ruv= V3 x sin(0.5 x HPBW[rad]), then it is expected that each cell edge corresponds to the edge of 3-dB beamwidth, (equivalently, the antenna gain is 3 dB down compared to the cell center.

[0269] For Set-1 LEO-600, 3-dB beamwidth (HPBW) of 4.4127° gives ruv= 0.0386 and duv= ABS = 0.0668 in the UV plane. The corresponding central hexagonal cell area is 0.0039 in the UV plane. This translates to the hexagonal cell radius of 25 km (equivalently, satellite beam diameter of 50 km) on the earth, we refer to this baseline beam layout as “narrower beam / cell”.

[0270] Considering the above agreement made in RAN1#116, we discuss now to identify a beam layout that can be useful in the mapping of beam footprint to wider cell. Specifically, we utilize the beam layout where the ABS is increased while keeping the 3-dB beamwidth unchanged and cells are mapped to beams such that antenna gain is down by larger than 3 dB at the cell edge. We express this mathematically as

[0271] ABS' = V3n x sin(0.5 x HPBW [rad]), (Eq. 2)

[0272] We refer to beam layouts utilizing ABS' with n > 1 as “wider beam / cell”. For instance, if we set n = 2, n = 2.5 and n = 3 in (Eq. 2), then ABS' = 0.0945, ABS' = 0.1054 and ABS' = 0.1157 , respectively, which translate to the hexagonal cell radius of 35.35 km, 39.52 km, and 43.3 km, respectively, (equivalently, satellite beam diameter of 70.7 km, 79 km and 86.6 km) on the earth. It is worth to mention that in this case the antenna gain from both intended and unintended satellite beams at the cell-edge is decreased and the corresponding impact on the coverage is studied by means of the CDFs of geometry SNR, SIR, and SINR as illustrated in [9].

[0273] If one increases the ABS by Vn then the hexagonal cell area increases by n . Therefore, by increasing the ABS, one can reduce the number of cells falling inside the region of interest and hence reduces the number of satellite beam footprints to cover the same area.

[0274] If one increases the ABS by Vn, then the hexagonal cell area increases by n in the UV plane. Then, the number of satellite beam footprints required to provide the coverage to the specific region of interest can be decreased by increasing the ABS in the UV plane.

[0275] Specifically, ABS' = 0.1054 with n = 2.5 allows to expand the cell area mapping to each beam footprint by factor of 2.5 and consequently the total number of required beam footprints corresponding to the satellite coverage region within 30 elevation is about 424. If we consider Set 1- 1 , Set 1-3, the total number of simultaneously active beams = 106. Thus, at least for Set 1-1 and Set 1-3, this beam layout (i.e. , ABS' = 0.1054 with n = 2.5 ) enables beam hopping where one beam is hopped across 4 cells in time allows can be supported and SSB with periodicity of 20 ms can be utilized.

[0276] RAN1 to consider beam layout with at least one increased value of ABS (e.g., 0.1054, equivalently, beam size of 79 km) with the same HPBW in the context of mapping of beam footprints to wider cell areas.

[0277] Beam hopping with the mapping of beam footprint to wider cells of size 79 km allows to reduce the number of required beam footprints or cell areas to cover the satellite coverage region within 30° elevation to 424 from 1058 (that correspond to narrower beam footprints)

[0278] In the beam hopping scheme with the mapping of beam footprint to wider cells of size 79 km, one beam is required to hop across 4 cells if the total number of simultaneous active beams equal to 106.

[0279] By considering the periodicity of different physical mandatory signals which are in the range of 20 ms to 160 ms and placing these signals subject to their timelines, one can compute the fraction of free slots available for data transmission, excluding the physical mandatory signals, which is presented in the next subsection.

[0280] ■ One beam is hopped across 4 cells with SSB periodicity of 20 ms

[0281] We start with the case of one beam is hopped across 4 cells in time. We consider SSB with default periodicity of 20 ms such that SSB and SIB1 have the same periodicity of SSB. Similarly, CSI-RS and TRS are also placed in the same slot with a periodicity of 80 ms. Also, other physical mandatory signals involved in the connection establishment are placed with a periodicity ranging from 80 ms to 160 ms. To assess the fraction of slots that are utilized for mandatory physical channels / signals during initial access and the free slots available for data transmission, we consider a total of 160 ms, i.e., 160 slots. Different physical channels and signals across 4 cells are placed in different time slots within the interval of this 160 ms and one such an example can be found in [7]. This include SSB, SIB1 , SIB19, CSI-RS, TRS, MSG2, MSG4, Paging, other SIBs, etc., in the downlink as well as PRACH, MSG3, MSG5, with and / or without HARQ, etc. in the uplink. Depending on whether HARQ is considered or not, it is found that:

[0282] • The fraction of free DL slots available for scheduling user data is about 25% - 30% (i.e., 40 to 48 free slots) and

[0283] • the fraction of free UL slots available is about 45% - 60% (72 to 96 free slots).

[0284] Therefore, on average, each cell gets 10 to 12 free slots and 18 to 24 free slots in the downlink and uplink, respectively. o Beam hopping for NTN cells operating with narrower beam footprints and extended SSB periodicity

[0285] In contrast to the wider beam footprints, each narrow beam is required to hop over 10 cells to cover the complete region corresponding to the 30° elevation angle under the satellite. Given that revisit time interval is limited by the SSB periodicity, then the dwell time available for each cell is very limited if we consider the default SSB periodicity of 20 ms and not sufficient to meet the requirements in terms of the resource allocation for all the mandatory PHY channels and signals. Alternatively, one needs to resort to the SSB periodicity extension to facilitate the reasonable dwell time for each cell. As the legacy UEs prior to release-19 expect according to TS 38.213 an SSB periodicity of 20 ms during initial cell selection, they may not be able to deal with an SSB periodicity larger than 20 ms and hence there is an issue of backward compatibility. Depending on the instant at which the legacy UE accesses the cell, the UE may or may not detect SSB over an observation period of 80 ms (i.e., the 80 ms over which PBCH can be combined as per the MIB periodicity assumed by the legacy UE, which would be now mismatched since SSB periodicity is 160 ms = MIB periodicity).

[0286] If the legacy UE happens to detect an SSB and aims at combining other PBCHs nothing will be found which perhaps can be seen as resembling a single-shot SSB, then the UE will start a subsequent observation period and no SSB will be found, not even a single SSB as to resemble at least a singleshot SSB.

[0287] In an NR NTN cell operating with SSB periodicity of 160 ms, the legacy UEs prior to release- 19 will face the issue of backward compatibility during initial cell selection while Release-19+ UEs will not have any issue.

[0288] Again, by performing the analysis on the timelines of physical and signals, it can be possible to support beam hopping with time reuse factor of 7, i.e., one beam is hopped across at most 7 cells in time. The sharing of single beam across 7 cells in time induces the following extensions to the periodicities of mandatory physical signals:

[0289] • SSB (and MIB), SIB1 , CSI-RS, TRS and paging channels, e.g., 160 ms.

[0290] • PRACH occasions every 160 ms

[0291] If SSB periodicity of 160 ms is utilized to facilitate beam hopping where one beam is hopped across 7 cells, it is desirable to extend the periodicities of mandatory physical signals also to 160 ms: MIB, SIB1 , CSI-RS, TRS, paging channels, PRACH occasions, etc.

[0292] Again, in this beam hopping scheme, we evaluate for the fraction of free slots available for data transmission, excluding the physical mandatory signals.

[0293] ■ One beam is hopped across 7 cells with SSB periodicity of 160 ms

[0294] We conduct a similar analysis as in Section 4.1.2. SSB with a periodicity of 160 ms is considered such that SSB and SIB1 have the same periodicity of SSB. And the other physical mandatory channels and signals involved in the connection establishment are placed with a periodicity of 160 ms. Depending on whether HARQ is considered or not, it is found that:

[0295] • The fraction of free DL slots available for scheduling user data is about 34% - 39% (i.e., 55 to 62 free slots) and

[0296] • the fraction of free UL slots available is about 52% - 65% (83 to 104 free slots).

[0297] Therefore, on average, each cell gets 8 or 9 free slots and 12 to 15 free slots in the downlink and uplink, respectively. o Beam hopping for NTN cells operating with combination of wider and narrower beam footprints and extended SSB periodicity

[0298] In addition to the beam hopping schemes discussed in Sections 4.1 and 4.2, beam hopping with combination of wider and narrower beam footprints is also considered for the study as per the above agreement.

[0299] As illustrated in Figure 1 , DL common channels are transmitted over the wider beam footprint area (cf. Figure 1-a)) and wider beam footprint area hosts multiple narrower beam footprints over which the DL / UL dedicated channels may be transmitted (cf. Figure 1-b)), subject to the coverage and capacity requirements. Specifically, wider beam footprint and narrower beam footprints are multiplexed in time, but do not be simultaneously active due to mutual interference. In this case, the required revisit time, equivalently, the required SSB periodicity, to facilitate the desired dwell times for each cell can be bounded between 20 ms and the value required to support beam hopping with uniformly narrower beams.

[0300] Figure 6. Illustration of beam hopping utilizing combination of wider and narrower beam footprints, whereby DL common channels are transmitted over the wider beam footprint area as shown in a) and wider beam footprint area hosts multiple (e.g., two) narrower beam footprints over which the DL / UL dedicated channels may be transmitted as shown in b), subject to the coverage and capacity requirements.

[0301] In this variant of beam hopping scheme, it is essential to discuss the following aspects before considering any enhancements: • Partitioning of PHY channels and signals between wider and narrower beam footprints

[0302] • Desired periodicities of the signals

[0303] • Mechanism to identify the desired narrow beam footprint for the UEs within the area of wider beam footprint.

[0304] The wider beam footprint size determines the cell size, which in turn determines the link range. Thus, the decrease in the received SINR is subject to to this expansion of the cell size, which may or may not meet the link budget requirements for all the physical channels and signals in downlink and / or uplink. Therefore, it is important to discuss the criterion to be applied for partitioning the physical channels and signals between wider and narrower beam footprints.

[0305] RAN1 to discuss the criterion to be applied for partitioning the physical channels and signals between wider and narrower beam footprints.

[0306] As in the case of the other beam hopping scheme that maps the beam footprints to uniformly narrower cell sizes, in this beam hopping scheme also, the default SSB periodicity of 20 ms may or may not be sufficient to yield the reasonable dwell times for the cells. Hence, it is also necessary to discuss the periodicities of mandatory signals, including SSB.

[0307] RAN1 to discuss the periodicities to be applied for the mandatory physical signals, including SSB, in the context of beam hopping scheme that utilizes combination of wider and narrower beam footprints.

[0308] Next, depending on the signals partitioned between wider and narrower beam footprints, different approaches can be devised to identify the desired narrow beam footprint for the UEs within the cell area corresponding to wider beam footprint. For instance, if the PRACH transmission over the wider beam footprint does not meet the link budget requirements, then the network needs to facilitate PRACH transmission over narrower beam footprints and the corresponding PRACH occasions with respect to the narrow beam footprints separated in time. Alternatively, if the PRACH transmission is done over the wider beam footprint, then the network may utilize the CSI-RS resources to identify the desired narrow beam footprint based on the UE’s feedback. Hence, there exists different level of specification complexity depending on the approach used in this context.

[0309] RAN1 to discuss the mechanisms to identify the desired narrow beam footprint for the UEs within the area of wider beam footprint by accounting for the transmission of signals partitioned between wider and narrower beam footprints.

[0310] ■ One wider beam footprint is hopped across 4 cells, each hosting two narrower beam footprints to cover two regions, with extended SSB periodicity

[0311] We conduct a similar analysis as in Section 4.1.2. SSB with a periodicity of 160 ms is considered such that SSB and SIB1 have the same periodicity of SSB. And the other physical mandatory channels and signals involved in the connection establishment are placed with a periodicity of 160 ms. Depending on whether HARQ is considered or not, it is found that:

[0312] • The fraction of free DL slots available for scheduling user data is about 55% (i.e., 88 slots) and

[0313] • The fraction of free UL slots available is about 60% (96 free slots). Therefore, on average, each cell gets 11 free slots and 12 free slots in the downlink and uplink, respectively.

[0314] • Link-level enhancements In the RAN1#118 meeting, the following channels are considered for studying the link-level enhancements:

[0315] • PDCCH

[0316] • PDSCH with Msg 4

[0317] • PDSCH with SIB 1 / SIB 19.

[0318] We first recall below some of the observations and agreement made w.r.t. link-level coverage analysis for these channels.

[0319] To evaluate the link-level performance of PDCCH, we consider the settings as mentioned in the above agreement. It is also clear from the above observation that there is no coverage gap for PDCCH if we consider Set 1-1 / 1-2 in FR1 while there exists on average of 3.9 dB coverage gap with respect to CNR of -9.9 dB of Set 1-3. To optimize the coverage gap, it is discussed in the last RAN1 meeting that the number of simultaneous active beams reduced to yield CNR of -8 dB with Set 1-3 FR1 , which leads to the coverage gap for PDCCH is about 2 dB.

[0320] Fig. 19 shows PDCCH link-level performance in terms of initial BLER versus SNR (dB).

[0321] Table 4. Required SNR to meet the BLER target for PDCCH as function of aggregation factor.

[0322] Shown in Figure 19 is the link-level performance for PDCCH that is presented in terms of SNR vs. BLER for different aggregation factors: 1 , 2, 4, and 8. The corresponding SNR values to achieve the 1% initial BLER target are indicated in Table 4.

[0323] From the above, the coverage gap for PDSCH MSG4 and PDSCH SIB1-option 1 , PDSCH SIB1- option 2, and PDSCH SIB19 is about 4.7 dB, 4.1 dB, 6.5 dB, 3.5 dB, respectively, with respect to the CNR of -9.9 dB of Set 1-3 FR1. The coverage gap reduces to 2.8 dB, 2.2 dB, 4.6 dB, 1.6 dB, respectively if the CNR is optimized to -8 dB with Set 1-3. We now present the link-level evaluations for these physical channels for different number of repetitions to inspect for the required number of repetitions to fill the coverage gap with respect to the link budget CNR of -8 dB. Figure 20. PDSCH MSG4 link-level performance in terms of initial BLER versus SNR (dB).

[0324] Figure 21. PDSCH SIB1- option 1 (payload of 800 bits) link-level performance in terms of initial BLER versus SNR (dB).

[0325] Figure 22. PDSCH SIB1- option 2 (payload of 1280 bits) link-level performance in terms of initial BLER versus SNR (dB).

[0326] Figure 23. PDSCH SIB19 link-level performance in terms of initial BLER versus SNR (dB).

[0327] Table 5. Required SNR to meet the BLER target for PDSCH MSG4, PDSCH SIB1 with both optionl (payload 800 bits) and option 2 (payload 1280 bits) and PDSCH SIB19 as function of aggregation factor.

[0328] Shown in Figure 20, Figure 21 , Figure 22, and Figure 23 are the link-level performance for PDSCH MSG4, PDSCH SIB1 option 1 , PDSCH SIB1 option 2, and PDSCH SIB19, respectively, which are presented in terms of SNR vs. BLER for different aggregation factors: 1 , 2, 4, 8, and 16. The corresponding SNR values to achieve the 1% initial BLER target are indicated in Table 5.

[0329] To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e., aggregation factor of 4) for PDCCH while meeting the BLER target.

[0330] To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e., aggregation factor of 4) for PDSCH MSG4 while meeting the BLER target.

[0331] To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions and 8 repetitions (i.e., aggregation factor of 4 and 8) for PDCH SIB1 option 1 and option 2, respectively, while meeting the BLER target.

[0332] To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e., aggregation factor of 4) for PDSCH SIB19 while meeting the BLER target. • Conclusion

[0333] In the previous sections we made the following observations:

[0334] Observation 1 The maximum value for the SSB periodicity in the existing specifications is 160 ms for different purposes such as rate matching and measurement timing configuration. Whereas for cell search (i.e., initial cell selection), the maximum value for the SSB periodicity in the existing specification is 20 ms.

[0335] Observation 2 The extension of SSB periodicity beyond 20 ms for cell search operation leads to backward compatibility issue for prior to release-19 UEs.

[0336] Observation 3 If the SSB periodicity is extended beyond 20 ms for cell search operation, it is beneficial to consider it to be at most 160 ms to limit the specification impact.

[0337] Observation 4 If the SSB periodicity is extended beyond 20 ms, the legacy UE may or may not be able to detect the SSB depending on whether the received signal observation interval overlaps with the time instant corresponding to the actual SSB transmission. This, in turn affects the cell search complexity as well as latency and success rate during initial cell selection of the legacy UEs.

[0338] Observation 5 Network operation cannot be viewed solely in terms of the downlink as the UE is expected to initiate uplink communication following the reception of certain downlink physical channels and signals.

[0339] Observation 6 In an NR NTN cell operating with SSB periodicity of 20 ms, the legacy UEs prior to rel-19 can operate as usual. On the other hand, the Rel-19+UEs would have to hypothesize whether it is dealing with a 20 ms SSB periodicity or a longer SSB periodicity.

[0340] Observation 7 If one increases the ABS by n, then the hexagonal cell area increases by n in the UV plane. Then, the number of satellite beam footprints required to provide the coverage to the specific region of interest can be decreased by increasing the ABS in the UV plane.

[0341] Observation 8 Beam hopping with the mapping of beam footprint to wider cells of size 79 km allows to reduce the number of required beam footprints or cell areas to cover the satellite coverage region within 30° elevation to 424 from 1058 (that correspond to narrower beam footprints)

[0342] Observation 9 In the beam hopping scheme with the mapping of beam footprint to wider cells of size 79 km, one beam is required to hop across 4 cells if the total number of simultaneous active beams equal to 106.

[0343] Observation 10 In an NR NTN cell operating with SSB periodicity of 160 ms, the legacy UEs prior to release-19 will face the issue of backward compatibility during initial cell selection while Release-19+ UEs will not have any issue.

[0344] Observation 11 If SSB periodicity of 160 ms is utilized to facilitate beam hopping where one beam is hopped across 7 cells, it is desirable to extend the periodicities of mandatory physical signals also to 160 ms: MIB, SIB1 , CSI-RS, TRS, paging channels, PRACH occasion, etc.

[0345] Observation 12 To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e. , aggregation factor of 4) for PDCCH while meeting the BLER target.

[0346] Observation 13 To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e., aggregation factor of 4) for PDSCH MSG4 while meeting the BLER target. Observation 14 To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions and 8 repetitions (i.e., aggregation factor of 4 and 8) for PDCH SIB1 option 1 and option 2, respectively, while meeting the BLER target.

[0347] Observation 15 To match the coverage gap with respect to -8 dB CNR of Set 1-3, it is desirable to have at least 4 repetitions (i.e., aggregation factor of 4) for PDSCH SIB19 while meeting the BLER target.

[0348] Based on the discussion in the previous sections we propose the following:

[0349] Proposal 1 RAN1 to consider the maximum value of 160 ms while considering the extension of SSB periodicity beyond 20 ms for cell search operation.

[0350] Proposal 2 RAN1 to investigate the impact of the periodicity of the remaining mandatory physical channels and signals (i.e., timelines of physical channels and signals) due to the extension of the SSB periodicity to a value larger than 20 ms for cell search operation.

[0351] Proposal 3 RAN1 to consider the mandatory signals of both downlink and uplink at least while investigating the periodicities based on the extended SSB periodicity for cell search operation.

[0352] Proposal 4 RAN1 to focus on the beam hopping implemented with NTN cells operating with SSB periodicity of either 20 ms or 160 ms.

[0353] Proposal 5 RAN1 to consider beam layout with at least one increased value of ABS (e.g., 0.1054, equivalently, beam size of 79 km) with the same HPBW in the context of mapping of beam footprints to wider cell areas.

[0354] Proposal 6 RAN1 to discuss the criterion to be applied for partitioning the physical channels and signals between wider and narrower beam footprints.

[0355] Proposal 7 RAN1 to discuss the periodicities to be applied for the mandatory physical signals, including SSB, in the context of beam hopping scheme that utilizes combination of wider and narrower beam footprints.

[0356] Proposal 8 RAN1 to discuss the mechanisms to identify the desired narrow beam footprint for the UEs within the area of wider beam footprint by accounting for the transmission of signals partitioned between wider and narrower beam footprints.

[0357] • References

[0358] RP-241667, “New WID: Non-Terrestrial Networks (NTN) for NR Phase 3”, 3GPP TSG RAN Meeting #104, Shanghai, China, June 17-20, 2024.

[0359] R1 ■2407482, Session notes for 9.11 (Non-Terrestrial Networks for NR Phase 3 and Internet of

[0360] Things Phase 3), Ad-Hoc Chair (Huawei), RAN1#118, August 2024.

[0361] R1 -2405699, Session notes for 9.11 (Non-Terrestrial Networks for NR Phase 3 and Internet of Things Phase 3), Ad-Hoc Chair (Huawei), RAN1#117, May 2024.

[0362] R1 ■2403666, Session notes for 9.11 (Non-Terrestrial Networks for NR Phase 3 and Internet of

[0363] Things Phase 3), Ad-Hoc Chair (Huawei), RAN1#116-bis, April 2024.

[0364] R1 ■2401769, Session notes for 9.11 (Non-Terrestrial Networks for NR Phase 3 and Internet of

[0365] Things Phase 3), Ad-Hoc Chair (Huawei), RAN1#116, March 2024.

[0366] R1 -2406437, FL Summary #3: NR-NTN downlink coverage enhancements, Moderator (Thales), RAN1#118, August 2024. 3GPP TS38.213, ”5G NR Physical layer procedures for control”, v18.2.0, May 2024.

[0367] 3GPP TR 38.821 , "Solutions for NR to support Non-Terrestrial Networks (NTN)", v16.1 .0 June 2021 .

[0368] R1-2403989, “On NR-NTN downlink coverage enhancement”, Ericsson, RAN1#117, May 2024.

[0369] • Annex A: beam layout definitions for single satellite simulation

[0370] Table 6.1.1.1 -4: Beam layout definition for single satellite simulation [6]

[0371] • Annex B: Relevant RAN1 agreements

[0372] According to the following agreed satellite parameters for LEO 600 km for Set 1 in FR1 within the downlink coverage enhancement study, simultaneous active beams are 10.02%, 1.5% and 10.02% for Set 1 -1 , Set 1 -2, and Set 1 -3, respectively. This determines the fraction of area that can be served under the satellite footprint. One way to increase the fraction of coverage area is to increase the number of simultaneous active beams. However, due to the power budget and number of RF chains available at the satellite pay load, the number of active beams can’t be increased beyond certain limit. This eventually leads to the utilization of the so-called beam hopping, whereby one specific beam is used to illuminate multiple cells across different time instants. Some of the relevant agreements from the previous meetings are summarized below.

[0373] Table 6. Additional reference satellite parameters for LEO 600 km Set 1-1 FR1.

[0374]

[0375] Table 7. Additional reference satellite parameters for LEO 600 km Set 1-2 FR1. Table 8. Additional reference satellite parameters for LEO 600 km Set 1-3 FR1. RAN1 also agreed to use the following methodology in the context of system-level evaluation of DL coverage enhancement during RAN1#116

Claims

73CLAIMS1. A method performed by a network node (12) for handling synchronization indications in a wireless communication network, the method comprising: transmitting (1200) a first synchronization indication and a second synchronization indication, towards a user equipment, UE, (10), wherein the first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

2. The method according to claim 1 , wherein the first synchronization raster point is different than the second synchronization raster point.

3. The method according to any of the claims 1-2, wherein the first type is a nonpunctured synchronization signal and physical broadcast channel, PBCH, block, SSB, and the second type is a punctured SSB, or a cell defining SSB, CD-SSB.

4. The method according to claim 3, wherein the punctured SSB encompasses 12-physical resource blocks, PRB, in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB encompasses 20-PRBs in the frequency-domain and 4 symbols in the time-domain.

5. The method according to any of the claims 1-4, wherein the second periodicity is any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and wherein the first periodicity is 20 ms.

6. The method according to any of the claims 1-5, wherein the first synchronization indication is transmitted with the first periodicity during initial cell selection and once the UE (10) is in connected-mode, the first synchronization indication is transmitted with the second periodicity.

7. The method according to any of the claims 1-6, wherein the second synchronization indication is transmitted with the second periodicity at a same74 synchronization raster point and a different time instance as the first synchronization indication.

8. The method according to any of the claims 1-7, wherein the first synchronization indication and the second synchronization indication are transmitted in one or more beam footprints configured to serve or cover the UE (10).

9. The method according to any of the claims 1-8, wherein the wireless communication network comprises a non terrestrial network.

10. The method according to any of the claims 1-9, wherein the first and second synchronization indications comprise a respective synchronization signal and PBCH block.

11. The method according to any of the claims 1-10, wherein the first synchronization indication and the second synchronization indication are transmitted towards the UE (10) during initial cell selection.

12. The method according to any of the claims 1-11, wherein the first synchronization indication is transmitted in a wider beam of a first frequency range and the second synchronization indication is transmitted in a narrower beam in a second frequency range.

13. A method performed by a user equipment, UE, (10) for handling synchronization indications in a wireless communication network, the method comprising: receiving (1201) from a network node (12), a synchronization indication being one out of a first synchronization indication and a second synchronization indication, wherein the first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

14. The method according to claim 13, wherein the first synchronization raster point is different than the second synchronization raster point.7515. The method according to any of the claims 13-14, wherein the first type is a non-punctured synchronization signal and physical broadcast channel, PBCH, block, SSB, and the second type is a punctured SSB or a cell defining SSB, CD-SSB.

16. The method according to claim 15, wherein the punctured SSB encompasses 12-physical resource blocks, PRB, in the frequency-domain and 4 symbols in the time-domain; and / or the non-punctured SSB encompasses 20-PRBs in the frequency-domain and 4 symbols in the time-domain.

17. The method according to any of the claims 13-16, further comprising performing (1202) initial cell selection based on the received synchronization indication.

18. The method according to any of the claims 13-17, wherein the second periodicity is any of the following SSB periodicities 40 ms, 80 ms, and 160 ms; and wherein the first periodicity is 20 ms.

19. The method according to any of the claims 13-18, wherein the first synchronization indication is received with the first periodicity during initial cell selection and once the UE (10) is in connected-mode, the first synchronization indication is received with the second periodicity.

20. The method according to any of the claims 13-19, wherein the first synchronization indication and the second synchronization indication are received in one or more beam footprints configured to serve or cover the UE (10).

21. The method according to any of the claims 13-20, wherein the wireless communication network comprises a non terrestrial network.

22. The method according to any of the claims 13-21 , wherein the first and second synchronization indications comprise a respective synchronization signal and PBCH block.7623. A network node (12) for handling synchronization indications in a wireless communication network, wherein the network node is configured to: transmit a first synchronization indication and a second synchronization indication, towards a user equipment, UE, (10), wherein the first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

24. The network node according to claim 23, wherein the network node is configured to perform the method according to any of the claims 2-12.

25. A user equipment, UE, (10) for handling synchronization indications in a wireless communication network, wherein the UE (10) is configured to: receive from a network node (12), a synchronization indication being one out of a first synchronization indication and a second synchronization indication, wherein the first synchronization indication is of a first type transmitted with a first periodicity at a first synchronization raster point, and the second synchronization indication is of a second type transmitted with a second periodicity, being longer than the first periodicity, at a second synchronization raster point.

26. The UE (10) according to claim 25, wherein the UE (10) is configured to perform the method according to any of the claims 14-22.

27. A computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-22, as performed by the UE (10) and the network node (12), respectively.

28. A computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-22, as performed by the UE (10) and the network node (12), respectively.

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