EP4659499A1

EP4659499A1 - Synchronization for dynamic spectrum sharing between cellular systems

Info

Publication number: EP4659499A1
Application number: EP23703012.7A
Authority: EP
Inventors: Kari Juhani Hooli; Esa Tapani Tiirola
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2023-01-31
Filing date: 2023-01-31
Publication date: 2025-12-10
Also published as: WO2024160353A1; CN120917814A

Abstract

The disclosure relates to an apparatus comprising: means for receiving (800), from a network element, a synchronization signal block for a first cellular system; means for receiving (802), from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system; and means for deriving (804) content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

Description

SYNCHRONIZATION FOR DYNAMIC SPECTRUM SHARING BETWEEN CELLULAR SYSTEMS

Field of the disclosure

The present disclosure relates to an apparatus, a method, and a computer program for sending and receiving synchronization signal blocks for a first cellular system and a second cellular system.

For the purposes of the present disclosure, the phrases “at least one of A or B”, “at least one of A and B”, “A and/or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrases “A or B” and “A and/or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

Background

A communication system can be seen as a facility that enables communication sessions between two or more entities such as communication devices, base stations and/or other nodes by providing carriers between the various entities involved in the communications path.

The communication system may be a wireless communication system. Examples of wireless systems comprise public land mobile networks (PLMN) operating based on radio standards such as those provided by 3GPP, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). The wireless systems can typically be divided into cells, and are therefore often referred to as cellular systems.

The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted and/or required to do. Communication protocols and/or parameters which shall be used for the connection are also typically defined. Examples of standard are the so-called 5G standards.

Summary

According to an aspect there is provided an apparatus comprising means for: means for receiving, from a network element, a synchronization signal block for a first cellular system; means for receiving, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system ; and means for deriving content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

The apparatus may comprise: means for receiving, from the network element, the synchronization signal block for the first cellular system comprising a physical broadcast channel for the first cellular system; means for receiving, from the network element or another network element, a physical broadcast channel extension for the second cellular system based on the physical broadcast channel for the first cellular system; and means for deriving content of a physical broadcast channel for the second cellular system based at least on the physical broadcast channel extension for the second cellular system.

The first cellular system may comprise a NR cellular system and the other second cellular system may comprise a 6G cellular system.

Content of a physical broadcast channel for the second cellular system may comprise a broadcast channel for the second cellular system.

The apparatus may comprise: means for deriving the content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system only. The apparatus may comprise: means for deriving the content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system and the physical broadcast channel extension for the second cellular system.

Information comprised in the physical broadcast channel extension for the second cellular system may override some information comprised in the physical broadcast channel for the first cellular system.

The apparatus may comprise: means for receiving, from the network element or another network element, a physical downlink shared channel for the second cellular system comprising a system information block for the second cellular system based on the physical broadcast channel extension for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system, the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

The apparatus may comprise: means for receiving, from the network element or another network element, a physical downlink shared channel for the second cellular system comprising a system information block for the second cellular system based on the physical broadcast channel extension for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

The physical broadcast channel extension for the second cellular system may comprise an indication of a physical downlink control channel configuration (e.g. control resource set). The apparatus may use the physical downlink control channel configuration to receive the physical downlink control channel for the second cellular system. The physical downlink control channel for the second cellular system may schedule the physical downlink shared channel for the second cellular system. The physical downlink shared channel for the second cellular system may comprise the system information block for the second cellular system.

The apparatus may comprise: means for receiving, from the network element or another network element, a physical downlink shared channel for the first cellular system comprising a system information block for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system, the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

The apparatus may comprise: means for receiving, from the network element or another network element, a physical downlink shared channel for the first cellular system comprising a system information block for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

The apparatus may comprise: means for detecting that the physical broadcast channel extension for the second cellular system is available based on an indication comprised in the synchronisation signal block for the first cellular system.

The apparatus may comprise: means for detecting that the synchronisation signal block for the first cellular system is received on a predetermined frequency position, wherein the predetermined frequency position indicates that the physical broadcast channel extension is available.

The apparatus may comprise: means for detecting that the physical broadcast channel extension is available based an indication comprised in the physical broadcast channel for the first cellular system. The apparatus may comprise: means for detecting that a master information block sent via the physical broadcast channel for the first cellular system comprises a reserved bit, wherein the reserved bit indicates that the physical broadcast channel extension is available.

The apparatus may comprise: means for detecting that a demodulation reference signal is received on resources allocated to the physical broadcast channel for the first cellular system and on additional resources not allocated to the physical broadcast channel for the first cellular system, wherein the demodulation reference signal received on additional resources indicates that the physical broadcast channel extension is available.

The apparatus may comprise: means for blindly detecting that the physical broadcast channel extension for the second cellular system is available based on predetermined candidate locations for the physical broadcast channel extension for the second cellular system.

The synchronisation signal block for the first cellular system and the synchronisation signal block for the second cellular system may have same periodicities; or the synchronisation signal block for the first cellular system and the synchronisation signal block for the second cellular system may have different periodicities.

The apparatus may comprise: means for determining that the apparatus operates on a frequency band amongst a plurality of frequency bands where both the first cellular system and the second cellular system operate and where dynamic spectrum sharing applies.

The apparatus may comprise: means for receiving, from the network element, the synchronization signal block for the first cellular system comprising at least one synchronization signal for the first cellular system and the physical broadcast channel for the first cellular system; and means for synchronizing to the network element based on the at least one synchronization signal for the first cellular system. The at least one synchronization may be for the first cellular system and the second cellular system. The first cellular system and the second cellular system may be synchronised.

According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a network element, a synchronization signal block for a first cellular system; receive, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system; and derive content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

According to an aspect there is provided an apparatus comprising circuitry configured to: receive, from a network element, a synchronization signal block for a first cellular system; receive, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system; and derive content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

According to an aspect there is provided a method comprising: receiving, from a network element, a synchronization signal block for a first cellular system; receiving, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system; and deriving content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system. According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to: receive, from a network element, a synchronization signal block for a first cellular system; receive, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system; and derive, from the network element, content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

According to an aspect there is provided an apparatus comprising means for: means for sending a synchronization signal block for a first cellular system; and means for sending a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable at least from the synchronization signal block extension for the second cellular system.

The apparatus may comprise: means for sending the synchronization signal block for the first cellular system comprising a physical broadcast channel for the first cellular system; and means for sending a physical broadcast channel extension for the second cellular system so that content of a physical broadcast channel for the second cellular system is derivable at least from the physical broadcast channel extension for the second cellular system.

The synchronisation signal block for the first cellular system may comprise an indication indicating that a physical broadcast channel extension for the second cellular system is available.

The apparatus may comprise: means for sending the synchronisation signal block for the first cellular system on a predetermined frequency position, wherein the predetermined frequency position indicates that the physical broadcast channel extension for the second cellular system is available. The physical broadcast channel for the first cellular system may comprises an indication indicating that the physical broadcast channel extension for the second cellular system is available.

The apparatus may comprise: means for sending a master information block via the physical broadcast channel for the first cellular system comprising a reserved bit, wherein the reserved bit indicates that the physical broadcast channel extension is available.

The apparatus may comprise: means for sending a demodulation reference signal on resources allocated to the physical broadcast channel for the first cellular system and on additional resources not allocated to the physical broadcast channel for the first cellular system, wherein the demodulation reference signal sent on additional resources indicates that the physical broadcast channel extension is available.

According to an aspect there is provided an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: send a synchronization signal block for a first cellular system; and send a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable at least from the synchronization signal block extension for the second cellular system.

According to an aspect there is provided an apparatus comprising circuitry configured to: send a synchronization signal block for a first cellular system; and send a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable at least from the synchronization signal block extension for the second cellular system.

According to an aspect there is provided a method comprising: sending a synchronization signal block for a first cellular system; and sending a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable at least from the synchronization signal block extension for the second cellular system.

According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to: send a synchronization signal block for a first cellular system; and send a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable at least from the synchronization signal block extension for the second cellular system.

According to an aspect, there is provided a computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

According to an aspect, there is provided a non-volatile tangible memory medium comprising program instructions stored thereon for performing at least one of the above methods.

In the above, many different aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the aspects described above.

Various other aspects are also described in the following detailed description and in the attached claims.

List of abbreviations

AF: Application Function AMF: Access and Mobility Management Function

API: Application Programming Interface

BS: Base Station

CU: Centralized Unit

DL: Downlink

DSS: Dynamic Sharing Spectrum

DU: Distributed Unit gNB: gNodeB

GSM: Global System for Mobile communication

HSS: Home Subscriber Server loT : Internet of Things

LTE: Long Term Evolution

MAC: Medium Access Control

MIB : Master Information Block

MRSS: Multi Radio Spectrum Sharing

MS: Mobile Station

MTC: Machine Type Communication

NEF: Network Exposure Function

NF: Network Function

NR: New radio

NRF: Network Repository Function

PBCH: Physical Broadcast Channel

PDCCH: Physical Downlink Control Channel

PDSCH: Physical Downlink Share Channel

PDU: Packet Data Unit

PSS: Primary Synchronization Signal

RAM: Random Access Memory

(R)AN: (Radio) Access Network

RB: Resource Block

ROM: Read Only Memory

SIB : System Information Block SIBCH: Synchronization Information and initial system information or Broadcast

Channel

SMF: Session Management Function

SSB: Synchronization Signal/PBCH Block

SSS: Secondary Synchronization Signal

TR: Technical Report

TS: Technical Specification

UE: User Equipment

UMTS: Universal Mobile Telecommunication System

3GPP: 3^rd Generation Partnership Project

5G: 5^th Generation

5GC: 5G Core network

6G: 6^th Generation

Brief Description of the

Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

Figure 1 shows a schematic representation of a NR system;

Figure 2 shows a schematic representation of a control apparatus;

Figure 3 shows a schematic representation of a user equipment;

Figure 4 shows the structure of a NR synchronization signal block;

Figure 5 shows the structure of a NR synchronization signal block frequency division multiplexed with a physical broadcast channel;

Figure 6 shows the structure of a NR synchronization signal block time division multiplexed with a physical broadcast channel; Figure 7 shows a block diagram of a method for receiving synchronization signal blocks for a NR system and a 6G system performed by a 6G UE;

Figure 8 shows a block diagram of a method for receiving synchronization signal blocks for a first cellular system and a second cellular system performed by an apparatus, such as a user equipment;

Figure 9 shows a block diagram of a method for receiving synchronization signal blocks for a first cellular system and a second cellular system performed by an apparatus, such as a base station; and

Figure 10 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the methods of Figures 8 and 9.

Detailed Description of the Figures

In the following certain embodiments are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Figures 1 , 2 and 3 to assist in understanding the technology underlying the described examples.

Figure 1 shows a schematic representation of a NR system (i.e. 5G system or 5G- Advanced system). The NR system may comprise a user equipment (UE), a (radio) access network ((R)AN), a 5G core network (5GC), one or more application functions (AF) and one or more data networks (DN).

The 5G (R)AN may comprise one or more gNodeB (gNB) distributed unit functions connected to one or more gNodeB (gNB) centralized unit functions. gNB distributed unit functions may be part of relay nodes (e.g. distributed unit part of integrated access and backhaul nodes).

The 5GC may comprise an access and mobility management function (AMF), a session management function (SMF), an authentication server function (ALISF), a user data management (UDM), a user plane function (UPF) and/or a network exposure function (NEF).

Figure 2 illustrates an example of a control apparatus 200 for controlling a function of the (R)AN or the 5GC as illustrated on Figure 1 . The control apparatus may comprise at least one random access memory (RAM) 211 a, at least on read only memory (ROM) 211 b, at least one processor 212, 213 and an input/output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211 a and the ROM 211 b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211 b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5G (R)AN or the 5GC. In some embodiments, each function of the (R)AN or the 5GC comprises a control apparatus 200. In alternative embodiments, two or more functions of the (R)AN or the 5GC may share a control apparatus.

Figure 3 illustrates an example of a UE 300, such as the UE illustrated on Figure 1. The UE 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, a Cellular Internet of things (CloT) device or any combinations of these or the like. The UE 300 may be part of a relay node (e.g. mobile termination part of an integrated access and backhaul node). The UE 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

The UE 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 3 transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

The UE 300 may be provided with at least one processor 301 , at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 302a.

The processor, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as keypad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

One or more aspect of this disclosure relate to dynamic spectrum sharing (DSS) between cellular systems, in particular between a NR system and a 6G system. DSS may comprise resource element DSS (i.e. frequency domain and time domain DSS, time domain DSS only or frequency domain DSS only). DSS may sometimes be called multi radio spectrum sharing (MRSS). MRSS may be implemented in FR1 bands (i.e. below 7 GHz) or in FR2 bands (mm wave). 6G systems will be the next generation cellular systems that will be standardized by 3GPP. 6G systems are currently developed and aligned across telecom industry in various research projects and forums. 3GPP studies on 6G systems radio interface aspects are expected to start at time frame of 2025 or even 2024.

DSS between cellular systems means that the cellular systems share the same spectrum in a dynamic manner. As an example DSS may be supported between a LTE system and NR system. DSS between a NR system and a 6G system may also be important as it allows for gradual migration from 5G frequency bands to 6G frequency bands, together with gradual migration from 5G UE to 6G UE.

With DSS between a NR system and a 6G system the resources allocated to the NR system may be flexibly shared with the 6G system based on at least one of the number 6G UEs and the amount of 6G traffic. It may be so that there are only limited amount of 6G frequency bands dedicated for the 6G system (as opposed to 6G frequency bands shared between the NR system and the 6G system), especially at lower frequency. Hence, DSS may facilitate smooth introduction of a 6G system with sufficient coverage. Additionally, network vendors and operators may want to facilitate smooth (software) upgrade of 5G hardware to 6G hardware.

DSS between a 5G system and a 6G system may require tight frequency and time synchronization between the 5G system and the 6G system. DSS may also require also coordination between the schedulers to avoid accidental collisions on the resource allocation. Consequently, the 6G system may use a waveform and/or a numerology that is compatible with the 5G system for efficient DSS (e.g. to avoid excessive guard bands and guard times between NR transmissions and 6G transmissions). For example, the waveform and/or a numerology of the NR system may form a subset of the waveform and/or a numerology of the 6G system. This may also be beneficial from implementation viewpoint. A NR channel raster defines the set of frequency positions on which an UL carrier or DL carrier may be centred.

A NR synchronization signal/PBCH block (SSB) is a core building block of the NR system. A NR SSB is used for initial cell search and selection, beam and cell measurements, radio link monitoring and new beam identification in the beam recovery procedure. The NR SSB may comprise a NR primary synchronization signal (PSS), a NR secondary synchronization signal (SSS) and a NR physical broadcast channel (PBCH). The NR PBCH may comprise a demodulation reference signal (DMRS) for NR PBCH demodulation.

Figure 4 shows the structure of a NR SSB. A NR SSB may span over twenty resource blocks (RBs) in the frequency domain and four orthogonal frequency division multiplexing (OFDM) symbols in the time domain. The NR PSS may be conveyed in a first OFDM symbol. The NR PBCH may be conveyed in a second OFDM symbol. The NR PBCH and the NR SSS may be conveyed in a third OFDM symbol. The NR PBCH may be conveyed on a fourth OFDM symbol.

A NR synchronization raster defines the set of frequency positions on which the NR SSB may be located. NR synchronization raster may set the set of frequency positions that need to be searched by a NR UE for initial cell search. To expedite cell search, the synchronization raster may be much sparser than the channel raster. For example, in NR frequency range 1 , the channel raster typically has a 100 kHz spacing. The synchronization raster has a cluster of three frequency positions every 1 .2 MHz, with the offsets in each cluster being 50, 150 and 250 kHz.

The NR PBCH may comprise a master information block (MIB). The MIB may comprise at least one of a system frame number, a subcarrier spacing for a cell, a frequency offset relative to the NR SSB for a cell and a NR PDCCH configuration (e.g. for control resource set or CORESET#0). The NR PDCCH configuration may define a set of resources that a NR UE should monitor to obtain scheduling information for NR PDSCH. The NR PDSCH may comprise a system information block 1 (SIB1 ). The MIB may comprise a reserved bit.

A technical problem with DSS between a NR system and a 6G system may be that the NR control signalling (e.g. NR SSB comprising NR PSS, NR SSS and NR PBCH) is required for the NR system and 6G control signaling (e.g. 6G SSB comprising 6G PSS, 6G SSS and 6G PBCH) is required for the 6G system. The 6G control signalling cause significant overhead.

In this disclosure a 6G SSB may comprise any 6G control signalling or initial control signalling. A 6G SSB may comprise synchronization information and initial system information or broadcast channel (SIBCH).

The overhead may be even more significant in a beam based NR system and a beam based 6G system where the NR control signalling (e.g. NR SSB comprising NR PSS, NR SSS and NR PBCH) and the 6G control signaling (e.g. 6G SSB comprising 6G PSS, 6G SSS and 6G PBCH) are transmitted sequentially (at least to some extent) to different beams.

One or more aspect of this disclosure provides a mechanism to allow DSS between a NR system and a 6G system whilst minimizing the overhead caused by the 6G control signalling.

One or more aspect of this disclosure provides a mechanism to allow DSS between a NR system and a 6G system whilst providing a NR UE with a NR SSB and a 6G UE with a 6G SSB in an efficient manner (e.g. reduced overhead).

One or more aspect of this disclosure provides a mechanism to allow DSS between a NR system and a 6G system whilst synchronizing a NR UE with the NR system and a 6G UE with the 6G system in an efficient manner (e.g. reduced overhead). One or more aspect of this disclosure provides a mechanism to allow DSS between a NR system and a 6G system whilst providing a NR UE with system information for the NR system and a 6G UE with system information for the 6G system in an efficient manner (e.g. reduced overhead).

Efficient DSS between a NR system and a 6G system may require time and frequency synchronization between the NR system and the 6G system. As a result, the use of NR timing and frequency may not provide significant restrictions.

A 6G PBCH extension may provide to a 6G UE additional information (e.g. additional 6G synchronization signal if the synchronization achieved with NR SSB is not suitable or sufficient for the 6G system).

The 6G PBCH extension may not need to follow 5G NR air interface design beyond timing, frequency location, and sufficient orthogonality with 5G NR signals (e.g. by using OFDM with same subcarrier spacing or by the use of guard bands).

One or more aspect of this disclosure provides a mechanism wherein a NR SSB and a 6G SSB are provided in a hierarchical structure. Part of the 6G SSB (e.g. 6G PSS and 6G SSS) may be part of the NR SSB and may be derived from the NR SSB. Part of the 6G SSB (e.g. 6G PBCH) may not be part of the NR SSB and may be derived from an extension (e.g. 6G PBCH extension) separate from the NR SSB.

Alternatively, all of the 6G SSB (e.g. 6G PSS, 6G SSS and 6G PBCH) may not be part of the NR SSB and may be derived from an extension (e.g. 6G PSS extension, 6G SSS extension and 6G PBCH extension) separate from the NR SSB.

One or more aspect of this disclosure provides a mechanism wherein a NR SSB and a 6G SIBCH are provided in a hierarchical structure. Part of the 6G SIBCH (e.g. 6G synchronization information) may be part of the NR SSB. Part of the 6G SIBCH (e.g. 6G initial system information or broadcast channel) may not be part of the NR SSB and may be derived from an extension (e.g. 6G initial system information or broadcast channel extension) separate from the NR SSB.

The NR SSB and the 6G SSB may have a same periodicity. That is, there may be a one-to-one mapping between the NR SSBs and the 6G SSB. Alternatively, the NR SSB and the 6G SSB may have different periodicity. That is, there may be a N-to-one mapping between the NR SSB and the 6G SSB. For example, there may be a two-to- one mapping between the NR SSB and the 6G SSB (i.e. the 6G SSB is sent every other NR SSB).

A 6G UE may have prior knowledge of predetermined frequency bands on which both a NR system and a 6G system may operate and on which DSS may be applied. When the 6G UE determines that the 6G UE operates on a frequency band amongst the predetermined frequency bands, the 6G UE may receive a 6G SSB as follows.

Initially, the 6G UE may receive a NR SSB from a BS. The 6G UE may be served by the BS or by another BS. The NR SSB may comprise a NR PSS, a NR SSS and a NR PBCH. The NR system and the 6G may be synchronized and therefore the NR PSS and the NR SSS may also be used as 6G PSS and 6G SSS (or 6G synchronization signal or to provide 6G synchronization information). Thus, the 6G UE may synchronize to the BS based on the NR PSS and the NR SSS.

The 6G UE may detect that a 6G PBCH extension is available for 6G UEs based on the NR SSB. The NR SSB may comprise an indication that a 6G PBCH extension is available for 6G UEs. The indication that the 6G PBCH extension is available for 6G UEs may be explicit or implicit.

An explicit indication may be conveyed in a reserved bit of a NR MIB sent via the NR PBCH. NR UEs may ignore the reserved bit.

An implicit indication that the 6G PBCH extension is available for 6G UEs may be conveyed by sending a DMRS on resources allocated to the NR PBCH and on additional resources not allocated to the NR PBCH. That is, the DMRS is not sent on twenty physical resource blocks as in legacy NR systems but is sent on more than twenty physical resource blocks. If the 6G UE detects that the DMRS is sent on resources allocated to the NR PBCH and on additional resources not allocated to the NR PBCH, the 6G UE may detect the indication that the 6G PBCH extension is available for 6G UEs.

Another implicit indication that the 6G PBCH extension is available for 6G UEs may be conveyed by sending the NR SSB on a frequency position (i.e. raster point) amongst predetermined frequency positions (i.e. raster points). The predetermined frequency positions may be a subset of frequency positions allowed to send a NR SSB. If the 6G UE detects that the frequency position (i.e. raster point) on which the NR SSB is sent is amongst predetermined frequency positions, the 6G UE may detect the indication that the PBCH extension is available for 6G UEs.

The 6G UE may determine the location (i.e. timing, frequency and/or quasi-colocation) of the PBCH extension based on the NR SSB. The 6G UE may use the time and/ or frequency synchronization determined based on the NR SSB. The 6G UE may apply a predetermined time offset and/or frequency offset to the time and/or frequency position on which NR SSB was detected to determine the time and/or frequency resources for the 6G PBCH extension. In other words, the 6G PBCH extension time and/or frequency location may be relative to the NR SSB time and/or frequency location. Further, the 6G UE may use the same beam, spatial domain filter or spatial receiver parameters (see 3GPP TS 38.214) as determined for NR SSB reception also for PBCH extension reception.

The 6G PBCH extension may be frequency division multiplexed with the NR SSB as illustrated on Figure 5. The 6G PBCH extension may be on resource blocks adjacent to resource blocks of the NR SSB. Additionally or alternatively, the 6G PBCH extension may be time division multiplexed with the NR SSB as illustrated in Figure 6. Some of NR SSB locations may carry the 6G PBCH extension instead of the NR PBCH.

It will be understood that the NR SSB may not necessarily comprise an indication that a 6G PBCH extension is available for 6G UEs. The 6G UE may blindly detect that the 6G PBCH extension is available for 6G UEs based on predetermined candidate locations for the 6G PBCH extension. The predetermined candidate locations may be relative to the location of the NR SSB.

The 6G UE may receive the 6G PBCH extension from the BS. The 6G UE may receive a 6G SIB (e.g. 6G SIB1 ) based on the 6G PBCH extension or the NR PBCH. The 6G PBCH extension or the NR PBCH may comprise information to receive the 6G SIB from the BS. The information may comprise 6G PDCCH configuration (e.g. 6G CORESET#0). The 6G PDCCH may schedule a 6G PDSCH (or 6G physical downlink data channel) comprising the 6G SIB. Alternatively, a NR PDCCH may schedule a NR PDSCH comprising the 6G SIB. The NR PDCCH may be transmitted on NR CORESET#0, where the NR PDCCH is identified with a 6G-specific RNTI. The identification may be based on masking PDCCH cyclic redundancy check with the 6G- specific RNTI. The 6G-specific RNTI may be predetermined (e.g. in standard) or indicated on the 6G PBCH extension.

The 6G PBCH extension may comprise an indication indicating whether the 6G UE may derive the content of the 6G PBCH, that is the 6G broadcast channel (BCH) (i.e. logical channel), based on the 6G PBCH extension only, based on the 6G PBCH extension and the NR PBCH or based on the 6G PBCH extension, the NR PBCH and the 6G SIB as explained below.

The 6G UE may derive the 6G BCH based at least on the 6G PBCH extension. The 6G BCH like the NR BCH may comprise system information. In an example, the 6G UE may derive the 6G BCH based on the 6G PBCH extension only (i.e. not based on the NR PBCH). Information contained in the 6G BCH comprises information contained in the 6G PBCH extension and does not comprise information contained in the NR PBCH.

In another example, the 6G UE may derive the 6G BCH based on the 6G PBCH extension and the NR PBCH. Information contained in the 6G BCH comprises information comprised in the 6G PBCH extension and information comprised in the NR PBCH. Information comprised in the 6G PBCH extension may override some of the information comprised in the NR PBCH. For example, “PDCCH Config for SIB1 (8 bits)” may be overridden by 6G BCH, while System Frame Number (SFN) for 6G may be derived based on NR PBCH.

In another example, the 6G UE may derive the 6G BCH based on the 6G PBCH extension, the NR PBCH and the 6G SIB. Information contained in the 6G BCH comprises information comprised in the 6G PBCH extension, information comprised in the NR PBCH and information comprised in the 6G SIB.

Information comprised in the NR PBCH may comprise at least one of a SSB index, a system frame number, a half-frame bit, reserved bits (2 or 0 bits), symbol time and frequency synchronization, cell barred.

Information comprised in the 6G PBCH extension may comprise at least one of a subcarrier spacing, SSB subcarrier offset, a downlink control channel configuration, a PDCCH configuration SIB1 , an offset to 6G downlink channel or a downlink waveform

Information contained in the 6G BCH may comprise at least one of a SSB index, a system frame number, a half-frame bit, reserved bits (2 or 0 bits), symbol time and frequency synchronization, cell barred from NR PBCH and at least one of a subcarrier spacing, SSB subcarrier offset, a downlink control channel configuration, a PDCCH configuration SIB1 , an offset to 6G downlink channel or a downlink waveform from 6G PBCH extension. The 6G PBCH may be sent in manner that prevents NR UEs to decoding the 6G PBCH. The 6G PBCH may use different encoding, scrambling, and/or mapping to resources than the NR PBCH.

Figure 7 shows a block diagram summarizing the method for receiving a NR SSB and a 6G SSB performed by a 6G UE described above.

In step 700, the 6G UE may receive from a 6G BS, a NR SSB comprising a NR PSS, a NR SSS and a NR PBCH.

In step 702, the 6G UE may synchronize to the BS based on the NR PSS and the NR SSS.

In step 704, the 6G UE may detect that a 6G PBCH extension is available.

In step 706, the 6G UE may receive, from the BS, the 6G PBCH extension.

In step 708, the 6G UE may receive, from the BS, a 6G SIB.

In step 710, the 6G UE may derive a 6G PBCH based on the 6G PBCH extension and possibly the NR PBCH and/or the 6G SIB.

Figure 8 shows a block diagram of a method for receiving SSBs for a first cellular system and a second cellular system performed by an apparatus, such as a UE.

In step 800, the apparatus may receive, from a network element, a SSB for a first cellular system. In step 802, the apparatus may receive, from the network element or another network element, a SSB extension for a second cellular system based on the SSB for the first cellular system. In step 804, the apparatus may derive, from the network element, content of a SSB for the second cellular system based at least on the SSB extension for the second cellular system. The apparatus may receive, from the network element, the SSB for the first cellular system comprising a PBCH for the first cellular system. The apparatus may receive, from the network element or another network element, a PBCH extension for the second cellular system based on the SSB for the first cellular system. The apparatus may derive, from the network element, content of a PBCH for the second cellular system based at least on the PBCH extension for the second cellular system.

Content of a PBCH for the second cellular system may comprise a BCH for the second cellular system.

The apparatus may derive the content of the PBCH for the second cellular system based on the PBCH extension for the second cellular system only.

The apparatus may derive the content of the PBCH for the second cellular system based on the PBCH for the first cellular system and the PBCH extension for the second cellular system.

Information comprised in the PBCH extension for the second cellular system may override some information comprised in the PBCH for the first cellular system.

The apparatus may receive, from the network element or another network element, a PDSCH for the second cellular system comprising a SIB for the second cellular system based on the PBCH extension for the second cellular system. The apparatus may derive content of the PBCH for the second cellular system based on the PBCH for the first cellular system, the PBCH extension for the second cellular system and the SIB for the second cellular system. The apparatus may receive, from the network element or another network element, a PDSCH for the second cellular system comprising a SIB for the second cellular system based on the PBCH extension for the second cellular system. The apparatus may derive content of the PBCH for the second cellular system based on the PBCH extension for the second cellular system and the SIB for the second cellular system.

The PBCH extension for the second cellular system may comprise an indication of a PDCCH configuration (e.g. control resource set). The apparatus may use the PDCCH configuration to receive the PDCCH for the second cellular system. The PDCCH for the second cellular system may schedule the PDSCH for the second cellular system. The PDSCH for the second cellular system may comprise the SIB for the second cellular system.

The apparatus may receive, from the network element or another network element, a PDSCH for the first cellular system comprising a SIB block for the second cellular system. The apparatus may derive content of the PBCH for the second cellular system based on the PBCH for the first cellular system, the PBCH extension for the second cellular system and the SIB for the second cellular system.

The apparatus may receive, from the network element or another network element, a PDSCH for the first cellular system comprising a SIB block for the second cellular system. The apparatus may derive content of the PBCH for the second cellular system based on the PBCH extension for the second cellular system and the SIB for the second cellular system.

The apparatus may detect that the PBCH extension for the second cellular system is available based on an indication comprised in the SSB for the first cellular system.

The apparatus may detect that the SSB for the first cellular system is received on a predetermined frequency position, wherein the predetermined frequency position indicates that the PBCH extension is available. The apparatus may detect that the PBCH extension is available based an indication comprised in the PBCH for the first cellular system.

The apparatus may detect that a MIB sent via the PBCH for the first cellular system comprises a reserved bit, wherein the reserved bit indicates that the PBCH is available.

The apparatus may detect that a DMRS is received on resources allocated to the PBCH for the first cellular system and on additional resources not allocated to the PBCH for the first cellular system, wherein the DMRS received on additional resources indicates that the PBCH extension is available.

The apparatus may blindly detect that the PBCH extension for the second cellular system is available based on predetermined candidate locations for the PBCH extension for the second cellular system.

The SSB for the first cellular system and the SSB for the second cellular system may have same periodicities or the SSB for the first cellular system and the SSB for the second cellular system may have different periodicities.

The apparatus may determine that the apparatus operates on a frequency band amongst a plurality of frequency bands where both the first cellular system and the second cellular system operate and where DSS applies.

The apparatus may receive, from the network element, the SSB for the first cellular system comprising at least one synchronization signal for the first cellular system and the PBCH for the first cellular system. The apparatus may synchronize to the network element based on the at least one synchronization signal for the first cellular system. The at least one synchronization may be for the first cellular system and the second cellular system. The first cellular system and the second cellular system may be synchronised.

Figure 9 shows a block diagram of a method for receiving SSBs for a first cellular system and a second cellular system performed by an apparatus, such as a BS.

In step 900, the apparatus may send a SSB for a first cellular system. In step 902, the apparatus may send a SSB extension for the second cellular system so that content of a SSB for a second cellular system is derivable at least from the SSB extension for the second cellular system.

The apparatus may send the SSB for the first cellular system comprising a PBCH for the first cellular system. The apparatus may send a PBCH extension for the second cellular system so that content of a PBCH for the second cellular system is derivable at least from the PBCH extension for the second cellular system.

The SSB for the first cellular system may comprise an indication indicating that a PBCH extension for the second cellular system is available.

The apparatus may send the SSB for the first cellular system on a predetermined frequency position, wherein the predetermined frequency position indicates that the PBCH extension for the second cellular system is available.

The PBCH for the first cellular system may comprise an indication indicating that the PBCH extension for the second cellular system is available.

The apparatus may send a MIB via PBCH for the first cellular system comprising a reserved bit, wherein the reserved bit indicates that the PBCH extension is available.

The apparatus may send a DMRS on resources allocated to the PBCH for the first cellular system and on additional resources not allocated to the PBCH for the first cellular system, wherein the DMRS sent on additional resources indicates that the PBCH extension is available.

Figure 10 shows a schematic representation of non-volatile memory media 1000 storing instructions and/or parameters which when executed by a processor allow the processor to perform one or more of the steps of the methods of Figures 8 and 9.

It is noted that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

It will be understood that although the above concepts have been discussed in the context of a NR system and a 6G system, one or more of these concepts may be applied to other cellular systems.

The embodiments may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any procedures, e.g., as in Figures 8 and 9, may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi-core processor architecture, as non-limiting examples.

Alternatively or additionally some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and/or method steps previously described. That circuitry may be provided in the base station and/or in the communications device.

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

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

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

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

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as the communications device or base station to perform the various functions previously described; and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example integrated device.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined in the appended claims.

Claims

1 . An apparatus comprising: means for receiving, from a network element, a synchronization signal block for a first cellular system; means for receiving , from the network element or another network element,, a synchronization signal block extension for a second cellular system, based on the synchronization signal block for the first cellular system; and means for deriving content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system.

2. The apparatus of claim 1 , comprising: means for receiving, from the network element, the synchronization signal block for the first cellular system comprising a physical broadcast channel for the first cellular system; means for receiving, from the network element or another network element, a physical broadcast channel extension for the second cellular system based on the physical broadcast channel for the first cellular system ; and means for deriving content of a physical broadcast channel for the second cellular system based at least on the physical broadcast channel extension for the second cellular system.

3. The apparatus of claim 2, comprising: means for deriving the content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system only.

4. The apparatus of claim 2, comprising: means for deriving the content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system and the physical broadcast channel extension for the second cellular system.

5. The apparatus of claim 2, comprising: means for receiving, from the network element or another network element, a physical downlink shared channel for the second cellular system comprising a system information block for the second cellular system based on the physical broadcast channel extension for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system, the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

6. The apparatus of claim 2, comprising: means for receiving, from the network element or another network element, a physical downlink shared channel for the second cellular system comprising a system information block for the second cellular system based on the physical broadcast channel extension for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

7. The apparatus of claim 2, comprising: means for receiving, from the network element or another network element, a physical downlink shared channel for the first cellular system comprising a system information block for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel for the first cellular system, the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

8. The apparatus of claim 2, comprising: means for receiving, from the network element or another network element, a physical downlink shared channel for the first cellular system comprising a system information block for the second cellular system; and means for deriving content of the physical broadcast channel for the second cellular system based on the physical broadcast channel extension for the second cellular system and the system information block for the second cellular system.

9. The apparatus of any of claims 1 to 7, comprising: means for detecting that the physical broadcast channel extension for the second cellular system is available based on an indication comprised in the synchronisation signal block for the first cellular system.

10. The apparatus of claim 9, comprising: means for detecting that the synchronisation signal block for the first cellular system is received on a predetermined frequency position, wherein the predetermined frequency position indicates that the physical broadcast channel extension is available.

11 . The apparatus of claim 9, comprising: means for detecting that the physical broadcast channel extension is available based an indication comprised in the physical broadcast channel for the first cellular system.

12. The apparatus of claim 11 , comprising: means for detecting that a master information block sent via the physical broadcast channel for the first cellular system comprises a reserved bit, wherein the reserved bit indicates that the physical broadcast channel extension is available.

13. The apparatus of claim 11 , comprising: means for detecting that a demodulation reference signal is received on resources allocated to the physical broadcast channel for the first cellular system and on additional resources not allocated to the physical broadcast channel for the first cellular system, wherein the demodulation reference signal received on additional resources indicates that the physical broadcast channel extension is available.

14. The apparatus of any of claims 1 to 5, comprising: means for blindly detecting that the physical broadcast channel extension for the second cellular system is available based on predetermined candidate locations for the physical broadcast channel extension for the second cellular system.

15. The apparatus of any of claims 1 to 14, wherein the synchronisation signal block for the first cellular system and the synchronisation signal block for the second cellular system have same periodicities; or wherein the synchronisation signal block for the first cellular system and the synchronisation signal block for the second cellular system have different periodicities.

16. The apparatus of any of claims 1 to 15, comprising: means for determining that the apparatus operates on a frequency band amongst a plurality of frequency bands where both the first cellular system and the second cellular system operate and where dynamic spectrum sharing applies.

17. The apparatus of any of claims 1 to 16, comprising: means for receiving, from the network element, the synchronization signal block for the first cellular system comprising at least one synchronization signal for the first cellular system and the physical broadcast channel for the first cellular system; and means for synchronizing to the network element based on the at least one synchronization signal for the first cellular system.

18. An apparatus comprising: means for sending a synchronization signal block for a first cellular system; and means for sending a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable from the synchronization signal block for the first cellular system and the synchronization signal block extension for the second cellular system.

19. The apparatus of claim 16, comprising: means for sending the synchronization signal block for the first cellular system comprising a physical broadcast channel for the first cellular system; and means for sending a physical broadcast channel extension for the second cellular system so that content of a physical broadcast channel for the second cellular system is derivable at least from the physical broadcast channel extension for the second cellular system.

20. The apparatus of claim 19, wherein the synchronisation signal block for the first cellular system comprises an indication indicating that a physical broadcast channel extension for the second cellular system is available.

21 . The apparatus of claim 20, comprising: means for sending the synchronisation signal block for the first cellular system on a predetermined frequency position, wherein the predetermined frequency position indicates that the physical broadcast channel extension for the second cellular system is available.

22. The apparatus of claim 20, wherein the physical broadcast channel for the first cellular system comprises an indication indicating that the physical broadcast channel extension for the second cellular system is available.

23. The apparatus of claim 22, comprising: means for sending a master information block via the physical broadcast channel for the first cellular system comprising a reserved bit, wherein the reserved bit indicates that the physical broadcast channel extension is available.

24. The apparatus of claim 22, comprising: means for sending a demodulation reference signal on resources allocated to the physical broadcast channel for the first cellular system and on additional resources not allocated to the physical broadcast channel for the first cellular system, wherein the demodulation reference signal sent on additional resources indicates that the physical broadcast channel extension is available.

25. A method comprising: receiving, from a network element, a synchronization signal block for a first cellular system; receiving, from the network element or another network element, a synchronization signal block extension for a second cellular system based on the synchronization signal block for the first cellular system ; and deriving content of a synchronization signal block for the second cellular system based at least on the synchronization signal block extension for the second cellular system

26. A method comprising: sending a synchronization signal block for a first cellular system; and sending a synchronization signal block extension for the second cellular system so that content of a synchronization signal block for a second cellular system is derivable from the synchronization signal block for the first cellular system and the synchronization signal block extension for the second cellular system.

27. A computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform the method of claim 25 or claim 26.