Joint communication and sensing

Abstract

There is disclosed a method of operating a radio node in a wireless communication net- work, the radio node being adapted for wireless communication, and being adapted for sensing and / or radar operation, the method comprising performing sensing operation based on sensing synchronisation signalling multiplexed with sensing signalling, the sens- 2960 ing synchronisation signalling being transmitted on a reference channel determined based on channel sounding The disclosure also pertains to related devices and methods.

Description

[0001] Joint Communication and Sensing

[0002] Technical field

[0003] This disclosure pertains to wireless communication and radar technology, in particular for high frequencies.

[0004] Background

[0005] For future wireless communication systems, combining wireless communication and sens- 5 ing (radar) is discussed, in particular using the same spectrum and / or hardware for both.

[0006] This is sometimes referred to as Joint Communication and Sensing (JCAS), or Integrated Sensing and Communication (IS AC); JCAS and IS AC may be used synonymously. Combining these functionalities brings a number of challenges.

[0007] Summary 10

[0008] It is an object of this disclosure to provide approaches of handling JCAS, in particular regarding multiplexing of communication signalling and sensing signalling. The approaches described may be utilised for one or more different frequencies ranges. For example, they may be implemented for frequency ranges (e.g., carrier bandwidth and / or system bandwidth) for sensing signalling and / or communication signalling of 1 GHz or more, 2GHz 15 or more, 5 GHz or more, or 6 GHz or more, or 10 GHz or more, and / or for millimetre wave communication, in particular for radio carrier frequencies around and / or above 52.6 GHz, which may be considered high radio frequencies (high frequency) and / or millimetre waves. The carrier frequency / ies may be between 52.6 and 140 GHz, e.g. with a lower border between 52.6, 55, 60, 71 GHz and / or a higher border between 71, 72, 90, 20 114, 140 GHz or higher, in particular between 55 and 90 GHz, or between 60 and 72 GHz; however, higher frequencies may be considered, in particular frequency of 71 GHz or 72GHz or above, and / or 100 GHz or above, and / or 140 GHz or above. The carrier frequency may in particular refer to a centre frequency or maximum frequency of the carrier. The radio nodes and / or network described herein may operate in wide-band, e.g. 25 with a carrier bandwidth (or bandwidth or carrier aggregation) of 400MHz or more, in particular 1 GHz or more, or 2 GHz or more, or even larger, e.g. 6 GHz or more, or 8 GHz or more; the scheduled or allocated bandwidth may be the carrier bandwidth, or be smaller, e.g. depending on channel and / or procedure. In some cases, operation may be based on an OFDM wave- form or a SC-FDM wave- form (e.g., downlink and / or 30 uplink), in particular a FDF-SC-FDM-based wave-form. However, operation based on a single carrier wave-form, e.g. SC-FDE (which may be pulse-shaped or Frequency Domain Filtered, e.g. based on modulation scheme and / or MGS), may be considered for downlink and / or uplink. In general, different wave-forms may be used for different communication directions. Communicating using or utilising a carrier and / or beam may correspond to 35

[0009] P111680W001 1 / 88 operating using or utilising the carrier and / or beam, and / or may comprise transmitting on the carrier and / or beam and / or receiving on the carrier and / or beam. Operation may be based on and / or associated to a numerology, which may indicate a sub-carrier spacing and / or duration of an allocation unit and / or an equivalent thereof, e.g., in comparison to an OFDM based system. A sub-carrier spacing or equivalent frequency interval may 40 for example correspond to 960 kHz, or 1920 kHz, e.g. representing the bandwidth of a subcarrier or equivalent.

[0010] The approaches are particularly advantageously implemented in a future 6th Generation (6G) telecommunication network or 6G radio access technology or network (RAT / RAN), in particular according to 3GPP (3rd Generation Partnership Project, a standardisation 45 organization). A suitable RAN may in particular be a RAN according to NR, for example release 18 or later, or LTE Evolution. However, the approaches may also be used with other RAT, for example future 5.5G systems or IEEE based systems.

[0011] There is disclosed a method of operating a radio node in a wireless communication network. The radio node is adapted for wireless communication, and is adapted for sensing 50 and / or radar operation. The method comprises performing sensing operation based on sensing synchronisation signalling multiplexed with sensing signalling, the sensing synchronisation signalling being transmitted on a reference channel (and / or reference path) determined based on channel sounding.

[0012] Also, a radio node for a wireless communication network is proposed. The radio node 55 is adapted for wireless communication, and further is adapted for sensing and / or radar operation. The radio node moreover is adapted for performing sensing operation based on sensing synchronisation signalling multiplexed with sensing signalling, the sensing synchronisation signalling being transmitted on a reference channel (and / or reference path) determined based on channel sounding. 60

[0013] Approaches described herein may facilitate efficient synchronisation for sensing, in particular in a bi-static or multi-static sensing scenario. However, it may also provide benefits in a mono-static scenario, e.g., for calibration and / or environment analysis.

[0014] In general, the radio node may be adapted and / or operate as transmitter and / or receiver in a bi-static and / or multi-static sensing operation and / or scenario. Performing 65 sensing operation may comprise transmitting and / or receiving sensing signalling and / or sensing synchronisation signalling, and / or transmitting and / or receiving measurement information based on sensing signalling, and / or transmitting and / or receiving configuration information; configuration information may pertain to the configuration of synchronisation sensing signalling and / or sensing signalling and / or reporting pertain to such. 70

[0015] P111680W001 2 / 88 Measurement information may pertain to measurement performed based on sensing signalling and / or synchronisation sensing signalling. Receiving sensing signalling may be based on, and / or may comprise, processing sensing signalling, e.g., based on sensing synchronisation signalling, and / or based on processing of the sensing synchronisation signalling. Sensing operation and / or receiving sensing signalling and / or processing sensing 75 signalling and / or sensing synchronisation signalling may comprise determining a Doppler-shift and / or phase and / or phase shift. The radio node may be adapted for transmitting both sensing synchronisation signalling and sensing signalling, and / or for receiving both sensing synchronisation signalling and sensing signalling, e.g., as sensing operation.

[0016] The reference channel (and / or reference path) may be associated to, and / or sensing syn- 80 chronisation signalling may be associated to and / or carried by, transmission on a transmission beam, and / or to reception on a reception beam, and / or be associated to a specific beam pair. The sensing signalling may be associated to a sensing channel (and / or sensing path), which may be different from the reference channel. A sensing channel may be associated to, and / or sensing signalling may be associated to and / or carried by, transmission 85 on a transmission beam, and / or to reception on a reception beam, and / or be associated to a specific beam pair; a beam, or the beams, associated to sensing signalling may be different to a beam, or the beams, associated to sensing synchronisation signalling, e.g., in terms of their direction / s, in particular their main direction / s. A sensing channel and / or an associated beam (e.g., a beam for transmission of sensing signalling, and / or a beam for 90 reception of sensing signalling, may be time- variable, e.g., due to sweeping, in particular over a time-scale of a subframe over less, and / or a slot or less, and / or a sub-slot or 10 or fewer symbols or less. A beam in question may be associated to a narrow beam, and / or a beam with an angular size of 45° or less, and / or 30° or less, and / or 10° or less, e.g., in vertical and / or horizontal plane. In general, transmission beams may have different 95 size than reception beams, and / or any beam may have different sizes in different planes.

[0017] It may be considered that the angular size, and / or spatial size, of a transmission beam and / or reception beam of sensing signalling and / or sensing synchronisation signalling, may be smaller or narrower than that of a beam used for transmission and / or reception of synchronisation signalling for the wireless communication network and / or RAN used 100 for wireless communication, e.g., SSB or SS / PBCH block. A channel may in particular pertain to a specific signalling path and / or propagation path of signalling, which may be LOS and / or NLOS, and / or may be a multi-path; the channel may represent conditions the signalling travelling the path is subjected to.

[0018] Sensing synchronisation signalling may comprise reference signalling for synchronisation 105 and / or calibration of sensing signalling, in particular for processing, and / or for performing synchronisation and / or fine-tuning of synchronisation and / or for determining phase-shift

[0019] P111680W001 3 / 88 and / or Doppler shift. The sensing synchronisation may be specific to a reference channel, and / or a receiver, and / or not be broadcast. It may be considered that sensing synchronisation signalling does not include one or more of an indication of a cell ID, and / or a 110 master information block, and / or PSS and / or SSS, and / or PBCH. Sensing signalling may comprise signalling, e.g., reference or data signalling, which may be intended for being reflected at a target and / or object. Multiplexing, and / or characteristics of multiplexing, may pertain to transmission and / or point of time of transmission; some characteristics may shift when being subjected to a channel or different channels. Sensing synchronisation 115 signalling may represent and / or comprise a sequence root, and / or comprise a sequence of modulation symbols and / or reference symbols. In general, the reference channel and / or sensing synchronisation signalling and / or sensing channel and / or sensing signalling may be target-specific and / or region-specific, and / or specific to a cooperating radio node in a bi-static and / or multi-static scenario; a region may be considered a geographical region, 120 e.g., within a cell and / or cell sector; it may be smaller than a region that could be covered and / or sensed by the radio node (e.g., in the applicable setup) e.g., 1 / 5 thereof or less, or 1 / 10 thereof or less.

[0020] The sensing synchronisation signalling and the sensing signalling may be orthogonalised relative to each other, e.g., in one or more domains. This may allow good separation 125 and / or processing, in particular to base processing of the sensing signalling on the sensing synchronisation signalling.

[0021] The sensing synchronisation signalling may be multiplexed with the sensing signalling based on frequency domain multiplexing, e.g., for orthogonalisation. The signallings may be on the same carrier and / or bandwidth part and / or frequency range; it may be con- 130 sidered that sensing synchronisation signalling and sensing signalling may be interleaved.

[0022] This may allow good spectrum occupancy. The sensing synchronisation signalling may be on a first frequency interval; the sensing signalling may be on a second frequency interval. The first and second frequency intervals may be disjunct and / or non-overlapping and / or may share a border in frequency domain (e.g., the end border of one interval 135 may be the starting border of the other interval). The first frequency interval may lead the second frequency interval in frequency domain, or vice versa. In general, there may be considered overlap of the first frequency interval and the second frequency interval, e.g., mixing symbols or signals of the sensing synchronisation signalling and the sensing signalling in frequency domain (e.g., alternating on sub-carriers, and / or resource blocks 140 and / or resource block groups). In some cases, the frequency domain multiplexing may be comb-based, e.g., such that sensing signalling is on a first comb, and sensing synchronisation signalling on a second comb; the combs may be of same size (e.g., 2), and / or shifted so as no overlap occurs between the signallings in frequency domain on sub-carriers

[0023] P111680W001 4 / 88 and / or resource blocks and / or resource block groups. The first frequency interval may 145 cover, and / or represent and / or correspond to, a frequency interval or bandwidth of 100 kHz or more, or 500kHz or more, or 1 MHz or more, or 10 MHz or more, or 100 MHz or more; the second frequency interval may cover, and / or represent and / or correspond to, a frequency interval or bandwidth of 100 kHz or more, or 500kHz or more, or 1 MHz or more, or 10 MHz or more, or 100 MHz or more. The sizes in frequency domain of the 150 first frequency interval and the second frequency interval may be the same, or may be different.

[0024] The sensing synchronisation signalling may be multiplexed with the sensing signalling based on time domain multiplexing. In some cases, the sensing synchronisation signalling may be transmitted in a first time interval, and the sensing signalling may be transmitted 155 in a second time interval. The first and second time intervals may be disjunct and / or non-overlapping and / or may share a border in time domain (e.g., the end border of one interval may be the starting border of the other interval). The first time interval may lead the second time interval in time, or vice versa. If the first time interval leads in time, it may facilitate processing the synchronisation sensing signalling before processing 160 the sensing signalling, which may allow preparing this later processing, for overall quick processing. However, different arrangement may be considered, e.g., considering scenarios with large differences in time delay between different signalling paths and / or channels, in which it may be advantageous to transmit the sensing signalling first. In general, there may be considered overlap of the first time interval and the second time interval, 165 e.g., mixing symbols or signals of the sensing synchronisation signalling and the sensing signalling in time domain (e.g., alternating on symbol time intervals, and / or allocation units). The first time interval may comprise one or more symbol time intervals, and / or half-symbol intervals, and / or sub-slots and / or slots, and / or the second time interval may comprise one or more symbol time intervals, and / or sub-slots and / or slots. The sizes in 170 time domain of the first time interval and the second time interval may be the same, or different. This may be particularly useful in scenarios with predictable time domain behaviour and / or utilising large frequency bandwidths for the sensing signalling.

[0025] It may be considered that the sensing synchronisation signalling may be multiplexed with the sensing signalling based on code domain multiplexing. This may allow optimising time 175 and / or frequency resource allocation, e.g., considering requirements of communication operation.

[0026] Channel sounding may be performed with the radio node as end point, e.g., for transmission and / or reception. In general, channel sounding may comprise transmitting and / or receiving, and / or processing, sounding signalling, e.g., reference signalling, which may al- 180

[0027] P111680W001 5 / 88 low channel estimation and / or signal quality and / or signal strength and / or timing and / or phase determination. In a bi-static and / or multi-static scenario, another radio node may represent a second endpoint, e.g. Channel sounding may be unidirectional (only one participant in sensing transmitting sounding signalling) or bi- or multidirectional (e.g., two or more radio nodes of the sensing transmitting sensing signalling, e.g., both radio nodes 185 in a bi-static scenario). For a mono-static scenario, reflection may be utilised to received the transmitted sounding signalling, e.g., at a wall and / or a known surface. In some cases, a reference channel, or one or more channels of a set of reference channels, may be a LOS channel (Line-of-Sight), which may allow optimised transmission conditions in comparison to NLOS (Non-LOS). However, the channel and / or channels of the set may 190 be NLOS.

[0028] In some variants, the reference channel (and / or reference path) may be one of a set of reference channels (and / or reference paths). The set may be determined based on channel sounding, e.g., in different directions (e.g., beam transmission and / or reception directions). At different times, different channels and / or different sets may be used. 195 This may allow flexible reaction to different conditions and / or changes in target and / or environment.

[0029] The sensing synchronisation signalling and the sensing signalling may be transmitted based on a set of shared transmission parameters. This may facilitate processing and / or utilising the synchronisation sensing signalling for processing sensing signalling. The set 200 may in particular comprise and / or pertain to angular size, and / or spatial size, and / or lobe structure, and / or power, and / or beamforming weights, and / or polarization co-phasing, and / or time windowing. Alternatively, or additionally, the same circuitry and / or hardware may be utilised (e.g., the same antenna / s and / or antenna element / s, and / or the same power amplifier and / or Liters and / or mixers, and / or transmitter chain / s and / or 205 receiver chain / s). In some cases, beam direction, and / or power may be different. The set may be shared between transmission on different channels and / or between transmission of sensing signalling and / or sensing synchronisation signalling, and / or between transmission and reception of one of the signallings and / or on one of the channels.

[0030] The sensing synchronisation signalling and the sensing signalling may be transmitted 210 and / or received based on different transmission and / or reception beams. The beams may in particular differ in regard of transmission direction and / or reception direction, and / or transmission power.

[0031] In general, transmission power for the sensing signalling and transmission power for the sensing synchronisation signalling may be different. In particular, the transmission power 215 for the sensing synchronisation signalling may be lower than the transmission power of the

[0032] P111680W001 6 / 88 sensing signalling, and / or may be adapted based on the channel sounding and / or feedback information from another radio node (e.g., receiver in a bi-static scenario), and / or be adapted to provide signal strength and / or signal quality at the receiver that is similar to the (expected or reported on) received sensing signalling. This may allow low PAPR, 220 leading to linearised processing. Similar in this context my mean the same order of magnitude, or with a deviation of at most 50%, or 25%, or 10%, or 5%, or less, wherein the deviation may be relative to the higher value. In some cases, the transmission power for the sensing synchronisation signalling may be dependent on a pathloss of the channel and / or path, and / or whether is a NLOS path or LOS path, and / or on a comparison of 225 the pathloss with a pathloss of the sensing signalling channel.

[0033] The terms sensing and / or sensing operation and / or radar operation may be used interchangeably. Sensing operation may be performed in a sensing mode. Communication and / or communication operation may be performed in a communication mode. Different antenna arrangements and / or different nodes may operate in different modes; in some 230 cases, different antenna arrangements of the same radio node may operate in different modes, e.g. using frequency domain multiplexing (e.g., in addition to and / or overlaid on time domain multiplexing). Sensing operation may comprise transmitting and / or receiving sensing signalling. Sensing signalling may be signalling intended to be bounced of one more targets, e.g. to determine a presence, and / or a location, and / or velocity, and / or 235 speed of the target / s from the reflected signalling. Sensing operation may be mono-static, or in some cases bi-static or multi-static.

[0034] Sensing signalling may also be referred to a sensing signal. Sensing synchronisation signalling may also be referred to as synchronisation signalling and / or reference signalling and / or synchronisation reference signalling (or signal instead signalling). The reference 240 channel may be associated to, and / or representative of, and / or also be referred to a reference path, and / or a synchronisation reference path. A channel or path associated to propagation of sensing signalling may be referred to as sensing path or sensing channel.

[0035] Sensing synchronisation signalling may be and / or comprise reference signalling. Sensing signalling may be and / or comprise reference signalling. Sensing synchronisation signalling 245 may be based on the same sequence / s and / or sequence root and / or type of reference signalling as sensing signalling, or be based on a different one.

[0036] It may generally be assumed that radio nodes in a bi-static or multi-static setup are capable and / or adapted to exchange information and / or parameters and / or measurement reports, e.g., via a suitable communication interface, which may include a wireless inter- 250 face and / or a cable-bound interface.

[0037] In general, signalling on a frequency interval may cover all subintervals and / or sub-carriers

[0038] P111680W001 7 / 88 of the frequency interval, or omit one or more or some of the subintervals and / or subcarriers, e.g., leaving them empty, or such that they may carry, and / or may allow multiplexing of, other signalling. Signalling in a time interval may cover all subintervals and / or 255 symbol time intervals in the time interval, or omit one or more or some of the subintervals and / or symbol time intervals, e.g., leaving them empty, or such that they carry, and / or may allow multiplexing of, other signalling.

[0039] It may be considered that communication signalling is based on a multi-carrier waveform, e.g. an OFDM wave-form, for example a DFT-s-OFDM based wave-form, and / or that 260 the communication signalling is based on a waveform with cyclic appendix. A cyclic appendix may generally be a cyclic prefix, or a cyclic suffix. The appendix may represent a repetition of a part of signalling carried by a symbol at its start (suffix) or end (prefix), which may be appended at the opposite of the symbol (end or start); e.g. a cyclic prefix may be considered a repetition of the signalling at the end of the symbol it pertains to. 265 A cyclic appendix may be associated to a specific symbol, it may have a duration shorter than the symbol duration, e.g. less than 1 / 4 of the symbol duration, or less than 1 / 6.

[0040] The radio node may operate in TDD mode, e.g. switching between DL periods and UL periods, e.g., for communication. A DL period may be a period in which the radio node operates using DL transmissions, an UL period may be a period in which the radio node 270 operates using UL transmissions (e.g., a network node may transmit during DL, and receive during UL, and vice versa for a wireless device). It may be considered that there is a TDD guard period between DL and UL periods and / or between UL and DL periods, which may comprise a number of symbol time intervals, e.g. 10 or more symbols, or 12 or more symbols; there may be the same duration for guard periods for DL / UL and UL / DL, 275 or different ones. The guard period may allow switching circuitry between the different communication directions and / or handling of interference (in particular considering that DL signalling tends to much more powerful than (received) UL signalling). Time domain multiplexing of sensing signalling and communication signalling may refer to and / or include and / or comprise and / or represent switching between communication mode and 280 sensing mode such that at different times, different modes are used at least for a part of the circuitry and / or antenna arrangements and / or signalling associated to the radio node.

[0041] An antenna arrangement may comprise one or more antenna elements and / or sub-arrays and / or panels; different antenna arrangements may comprise different antenna elements and / or sub-arrays and / or panels. Different antenna arrangements and / or panels and / or 285 sub-arrays and / or elements may be adapted to be controlled or controllable separately from each other. There may be the same number of DL and UL periods and / or the same duration associated to DL and UL (at least over a certain time interval, e.g. alternating such that one DL period is followed by one UL period, or vice versa, or different numbers

[0042] P111680W001 8 / 88 or durations, e.g. (roughly) 3:1 (e.g., 3 DL periods followed by a TDD guard period and 290 1 UL period), or (roughly) 2:1, or even (roughly) 1:2 or 1: NU with NU 3 or larger, for UL heavy scenarios. UL period durations may be the same as DL period durations, or different. The distribution and / or duration of DL and UL periods may be referred to as TDD pattern; the TDD pattern may be dynamically controllable (e.g., with DCI signalling), and / or configured or configurable, e.g. with higher layer signalling like RRC signalling 295 or RLC signalling, and / or may be semi-statically configurable or configured. The TDD pattern may describe the smallest time domain distribution of DL period / s and / or UL period / s and / or TDD guard period / s repeated over time, e.g. in one or more frames and / or subframes and / or slots and / or a time duration covering multiple repetitions of the TDD pattern. It may be considered that operating in sensing mode may comprise 300 both transmission and reception by the same radio node, independent of the TDD period associated to a communication mode. It may be considered that a sensing mode and / or sensing interval may be inserted and / or embedded and / or multiplexed into a time period nominally associated to DL and / or UL and / or a TDD guard period, in particular a DL / UL guard period. 305

[0043] The sensing signalling and communication signalling may be transmitted by the same transmitting node, e.g. the radio node, or by different nodes. In particular, it may be considered that the radio node transmits both communication signalling and sensing signalling, and may additionally monitor for and / or receive a reflection of the sensing signalling, e.g. in a mono-static scenario. In some cases, the radio node may receive the 310 communication signalling and the sensing signalling, and / or may additionally transmit the sensing signalling, e.g. in a mono-static scenario. In some cases, the radio may transmit the communication signalling and receive (and / or monitor for) the sensing signalling, and additionally may transmit the sensing signalling, or vice versa. It should be considered that the receiving sensing signalling may comprise, and / or be based on monitoring for 315 the sensing signalling, e.g. utilising one or more reception beams and / or beam sweeping.

[0044] Received or monitored for sensing signalling may represent reflected and / or diffracted sensing signalling, e.g. after impacting a target object and / or obstacle. Operation using sensing signalling and communication signalling may pertain to a specific time period, e.g. a joint operation interval, in which both communication and sensing is performed. 320 There may be operational states of the radio node focussing on one type of operation, e.g. only communicating or sensing. Sensing signalling being frequency multiplexed (also known as being frequency domain multiplexed, or frequency duplexed) with communication signalling may refer to the sensing signalling having a different location in frequency domain than the communication signalling, e.g. in non-overlapping parts of the spec- 325 trum (non-overlapping bandwidths). In particular, sensing signalling may occupy a first

[0045] P111680W001 9 / 88 frequency bandwidth, and the communication signalling may occupy a second frequency bandwidth, wherein the first and second frequency bandwidths may be non-overlapping and / or disjunct and / or separated in frequency domain.

[0046] The radio node may for example be a wireless device or user equipment or terminal, or 330 a network node or signalling radio node or base station. Thus, sensing functionality may be provided by common participants of a wireless communication network.

[0047] It may be considered that the radio node is adapted for utilising an antenna arrangement, which may comprise number NP of antenna elements and / or antenna sub-arrays and / or panels, wherein NP may be an integer number of 4 or larger, e.g., 32. An antenna 335 sub-array may comprise a plurality of individual antennas, e.g. 1 or 2 or 3 or 4 or more, or 10 or more, or 50 or more, or 100 or more. An antenna sub-array, and / or the antennas associated thereto and / or comprised therein, may be associated and / or connected or connectable to one and / or the same antenna circuitry, and / or be jointly controllable for analogue and / or digital beam-forming, and / or be operable for joint transmission or re- 340 ception. A panel may comprise a support structure, e.g. plastics and / or metallic material and / or wood, supporting one or more antenna arrangements sub-arrays, which additionally may support additional circuitry like antenna circuitry and / or interface circuitry.

[0048] Each antenna element or antenna sub-array may be switchable to, and / or associated to, and / or assignable and / or configurable to, one signalling direction, e.g., communication 345 direction and / or sensing direction (e.g., reception or transmission), and / or one functionality, e.g. sensing or communication. It may be considered that antennas of an antenna sub-array share the same polarisation, e.g. horizontal or vertical. In some cases, NP may be an even number, wherein it may be considered that NP / 2 antenna sub- arrays (and / or their antenna elements) may be associated to a first polarisation (e.g., horizontal or ver- 350 tical or left-circular or right-circular, or any other suitable polarisation) and the other NP / 2 antenna sub-arrays are associated to a second polarisation, which may be orthogonal to the first polarisation. For example, the first polarisation may be horizontal with the second polarisation being vertical, or the first polarisation may be left-circular and the second polarisation may be right- circular. This allows multiple beams to be operated, 355 with good flexibility and / or large signalling capacity. In general, an antenna arrangement associated to a radio node may comprise one or more antenna elements and / or antenna sub-arrays, in particular an even number of antenna sub-arrays. In general, at different times, different antenna sub-arrays and / or panels may be used for different functions, e.g. transmission or reception, and / or sensing or communication. The polarisation of an an- 360 tenna or antenna element or antenna sub-array may be associated to a specific operation direction, e.g. for transmission or reception. Depending on signalling direction (transmission or reception), polarisation may be different. For example, an antenna sub-array

[0049] P111680W001 10 / 88 may be associated to a first polarisation for transmission, and a second polarisation for reception, or vice versa. This may be achieved, for example, by providing crossed linear 365 antenna elements for the sub-arrays, with associated connections / circuitry according to polarisation. In some cases, an individual antenna element may be considered to represent an antenna sub-array. In particular, it may be considered that the sensing signalling is transmitted and / or received, e.g. by the radio node, utilising a first set of antenna elements and / or antenna sub-arrays and / or antenna panels, and the communication sig- 370 nailing is transmitted and / or received, e.g., by the radio node, utilising a second set of antenna elements and / or antenna sub-arrays and / or antenna panels. The first set may comprise different sub-arrays and / or antenna elements and / or antenna panels than the second set. The first set may comprise one or more antenna sub-arrays and / or panels, e.g. NC sub-arrays and / or panels, in particular an even number. It may be considered 375 that the second set may comprise one or more antenna sub-arrays and / or panels, e.g., NS sub-arrays, in particular an even number. It may be considered that NC+NS=NP. In some cases, the NC and / or NS sub-arrays and / or panels may comprise equal number of antenna sub-arrays and / or panels associated to first and second polarisations (in general, an antenna sub-array may be considered associated to a polarisation if all its antenna 380 elements are associated to the same polarisation). It may be considered that different antenna sub-arrays are used for transmitting sensing signalling and receiving signalling, wherein the same polarisation may be associated to transmitting and receiving of sensing signalling.

[0050] It may be considered that the sensing signalling and the communication signalling are 385 transmitted and / or received in an operation time interval, for example a slot, or an integer number N of symbol time intervals or allocation units or block symbols. The operation time interval may correspond to 1 ms or less, or 0.5 ms or less, or.1 ms or less, and / or N may be 1000 or less, or 300 or less, or 200 or less, or 100 or less, or 20 or less. Thus, the radio node may operate both signalling types in short timescales. Within the operation 390 time interval, the sensing signalling and communication signalling may be operated time multiplexed, or simultaneously, or both (in different sub- intervals). The operation time interval may encompass one or more sensing time intervals.

[0051] In some variants, the sensing signalling and the communication signalling may be transmitted and / or received at least partly, or fully, overlapping in time, e.g. in an operation 395 time interval, or one or more sub-intervals thereof. Partly overlapping in time may refer to part of the sensing signalling not overlapping with the communication signalling, fully overlapping may refer to all of the sensing signalling overlapping with communication signalling (in time domain, in particular within the operation time interval and / or one or more sub- intervals thereof). Within the sensing time interval, transmission and reception 400

[0052] P111680W001 11 / 88 of the sensing signalling may be performed and / or occur.

[0053] It may be considered that a first antenna sub-array and / or antenna panel may be used for transmitting sensing signalling, a second antenna sub-array and / or antenna panel may be used for monitoring and / or receiving a reflection of the sensing signalling. Two or more antenna sub-arrays and / or panels may be used for communicating utilising communication 405 signalling., e.g. during the operation time interval. The first and second sub-array and / or panel may be of different polarisation. In particular for large NP (e.g., 8 or larger), this may facilitate sensing operation with comparatively low impact on communication operation.

[0054] In general, sensing signalling and communication signalling may occupy the same fre- 410 quency spectrum, e.g. the same carrier. Frequency multiplexing may generally refer to different locations of the frequency spectrum being assigned to sensing signalling and communication signalling, e.g. different parts of the carrier bandwidth; additionally, different bandwidths may be assigned to sensing signalling and communication signalling.

[0055] Spectrum re-use thusly may be provided. This may refer to operation time interval / s. 415

[0056] It may be considered that the sensing signalling may occupy a bandwidth (first frequency bandwidth, or first bandwidth) of 350 MHz or less, or 300 MHz or less, and / or 10% or less of a carrier or system bandwidth, or 5% or less of a carrier or system bandwidth, and / or 10% or less of the bandwidth (second frequency bandwidth, or second bandwidth) used for communication signalling, and / or 7% or less of the bandwidth used for commu- 420 nication signalling. This may refer to operation time interval / s; outside of such, different bandwidth sizes may be used, e.g. if only communication signalling is used for a longer time (e.g., 5 or more times the operation time interval duration, or 10 or 20 or 50 or more times the operation time interval duration), the full carrier / system bandwidth may be applied for communication signalling. Thus, bandwidth limitation may be ameliorated. 425

[0057] In some variants, sensing signalling may occupy a first frequency bandwidth (or first bandwidth), and the communication signalling may occupy a second frequency bandwidth (second bandwidth), wherein further a frequency gap may exist, or be, or be located, between the first frequency bandwidth and the second frequency bandwidth. The second frequency bandwidth may be larger in size than the first frequency bandwidth, e.g. it 430 may be SM times the size, wherein SM may be 3 or more, or 5 or more, or 10 or more, or 15 or more. The gap may correspond to a bandwidth smaller than the second frequency bandwidth, and / or may be smaller than the first frequency bandwidth. The gap may correspond to a guard bandwidth, e.g. limiting interference between the first and second frequency bandwidths. 435

[0058] P111680W001 12 / 88 In general, the communication signalling may be based on an OFDM wave-form, for example a DFT-s-OFDM based wave-form. This may facilitated reliable communication with high capacity.

[0059] Approaches described herein facilitate using hardware of a communication radio node for radar or sensing, with limited overhead or loss of efficiency. 440

[0060] Sensing signalling may generally be represented by reference signalling. Sensing signalling of different types may differ in terms of numerology and / or wave-form and / or modulation symbol sequence and / or sequence root and / or duration and / or frequency bandwidth and / or density (e.g., in time domain and / or frequency domain) and / or code and / or timing, in particular regarding periodicity) and / or beam shape or beam size. 445

[0061] The communication signalling and / or sensing signalling may be based on an OFDM waveform, e.g. OFDM and / or SC-FDM. Transmitting and / or receiving sensing signalling may be considered operating utilising sensing signalling. It may be considered that operating utilising communication signalling, and / or communicating utilising communication signalling, may comprise transmitting the communication signalling and / or receiving the 450 communication signalling. Depending on whether the radio node is adapted for full-duplex operation or not, operating utilising sensing signalling may comprise operating in the same direction (e.g., both operations comprise or consists of transmitting, or both comprise or consist of receiving), or in different directions (for either or both operations, or between operations and / or for one operation). Thus, different use cases and types 455 of setup (mono-static or multi-static) may be considered. Communication signalling in general may comprise control signalling, e.g., on a control channel, and / or data signalling, e.g., on a data channel, and / or reference signalling, e.g., associated to control signalling and / or data signalling, or separate thereof.

[0062] In some cases, operating utilising sensing signalling may comprise transmitting the sensing 460 signalling and / or receiving the sensing signalling. In general, receiving sensing signalling may comprise receiving reflections of the sensing signalling; the reflections may be shifted in time relative to the transmitting signalling (due to propagation delay); the shift in time may two symbol time intervals or less, or one symbol time interval or less, or the duration of a cyclic prefix or less. The range of the sensing signalling may be configured 465 accordingly. In general, operating utilising sensing signalling may comprise performing sensing and / or determining the presence (or absence) of an object and / or determining one or more properties of one or more objects (sensing targets).

[0063] It may be considered that the communication signalling is based on an OFDM waveform, e.g. OFDM, or DFT-s-OFDM, or pulse-shaped DFT-s-OFDM. Such a wave-form 470

[0064] P111680W001 13 / 88 is particularly suitable for wireless communication at high frequencies and / or with high communication loads. In some cases, the sensing signalling may be based on an OFDM wave-form, e.g. OFDM, or DFT-s-OFDM, or pulse-shaped DFT-s-OFDM, or an OFTS based wave-form. The sensing signalling wave-form may be based on the same wave-form as the communication signalling, which allows easy reuse of configurations and circuitries. 475 In some cases, it may be based on a different wave-form, allowing flexibility, e.g. for different use cases and functionalities.

[0065] The radio node may be a wireless device or user equipment or terminal. Alternatively, it may be a network node or signalling radio node. A radio node adapted for wireless communication may be a radio node adapted for transmitting and / or receiving commu- 480 nication signalling, and / or for operating with signalling in conformance with a communication standard, e.g. according to a 3GPP standard, and / or adapted for communicating utilising control signalling in conformance with a standard (not necessarily data signalling). A radio node adapted for operating with signalling in conformance with a communication standard may be adapted for utilising signalling and / or waveforms ac- 485 cording to the standard, and / or circuitry capable of producing such waveforms and / or signalling. Communication signalling may be. and / or comprise, data signalling and / or control signalling and / or reference signalling, e.g. according to a wireless communication standard like a 3GPP standard or IEEE standard. A radio node adapted for sensing operation and / or radar operation may be adapted for, and / or be configured or config- 490 urable, for transmitting and / or receiving signalling for sensing or radar functionality, in particular according to a configuration for sensing and / or processing signalling. The radio node may share circuitry like processing circuitry and / or radio circuitry and / or antenna circuitry and / or antenna elements and / or sub-arrays between communication signalling and sensing operation and / or sensing signalling. The sensing operation may be mono- 495 static and / or multi-static. Sensing signalling may be reference signalling, and / or may be communication signalling and / or signalling dedicated for sensing. Sensing signalling may have different types of signalling, e.g. based on, or associated to use and / or object and / or sensing function (e.g., which parameters of an object are to be determined).

[0066] Multiplexing communication signalling and sensing signalling in a multiplexing time in- 500 terval may correspond to the communication signalling and the sensing signalling being transmitted in the multiplexing time interval, e.g. by the same node or different nodes.

[0067] Operating utilising communication signalling may comprise transmitting and / or receiving communication signalling. Operating utilising sensing signalling may comprise transmitting and / or receiving sensing signalling. A radio node may be adapted for mono-static 505 operation. In this case, it may be adapted for full-duplex operation, transmitting and receiving in fully or at least partially overlapping time intervals (e.g., corresponding to,

[0068] P111680W001 14 / 88 and / or at least partially overlapping with, the multiplexing time interval), such that it may receive reflected sensing signalling it transmitted itself (due to the large speed of radio waves, the reflected sensing signalling will often be received while the radio node 510 still transmits sensing signalling). The radio circuitry and / or processing circuitry and / or antenna circuitry of a radio node may be adapted both for handling communication signalling and sensing signalling. The radio node may be adapted for full-duplex operation, and / or half-duplex operation. Full duplex may refer to transmitting and receiving at the same time, e.g. using the same or different circuitries, and / or using different antenna 515 sub-arrays or separately operable antenna sub-arrays or antenna elements.

[0069] The sensing signalling may be beam-formed. Communication signalling may be beam-formed. Different beams, in particular narrower beams, may be used for the sensing signalling than the communication signalling. In some cases, the beam shapes of sensing signalling may be different for different occurrences and / or signalling types and / or func- 520 tionalities of sensing signalling. Beam-switching may be performed when switching from communication signalling to sensing signalling, and vice versa. Sensing signalling may be transmitted with a sensing beam and / or isotropically or with a default beam; it may be received with a reception beam, or with a default or isotropic reception. A sensing beam may be swept through a spatial angle, e.g. according to a sweeping scheme to perform 525 sensing in the spatial angle.

[0070] A DFT-s-OFDM based wave-form may be a wave-form constructed by performing a DFT-spreading operation on modulation symbols mapped to a frequency interval (e.g., subcarriers), e.g. to provide a time- variable signal. A DFT-s-OFDM based wave-form may also be referred to a SC-FDM wave-form. It may be considered to provide good PAPR 530 characteristics, allowing optimised operation of power amplifiers, in particular for high frequencies. In general, the approaches described herein may also be applicable to SingleCarrier based wave-forms, e.g. FDE-based wave-forms. Communication, e.g. on data channel / s and / or control channel / s, may be based on, and / o utilise, a DFT-s-OFDM based wave-form, or a Single-Carrier based wave-form. 535

[0071] Communication may in particular on multiple communication links and / or beams and / or with multiple targets (e.g., TRPs or other forms of transmission sources also receiving) and / or multiple layers at the same time; different reference signallings for multiple transmission or reception may be based on different sequence roots and / or combs and / or cyclic shifts. Thus, high throughput may be achieved, with low interference. In general, different 540 reference signallings (e.g., of the same type) may be associated to different transmission sources and / or beams and / or layers, in particular if transmitted simultaneously and / or overlapping in time (e.g., considering different timing advance values if transmitted in

[0072] P111680W001 15 / 88 uplink). For example, there may be first reference signalling transmitted using a first transmission source and / or first beam and / or first layer, and second reference signalling 545 transmitted using a first transmission source and / or first beam and / or first layer.

[0073] There is also described a program product comprising instructions causing processing circuitry to control and / or perform a method as described herein. Moreover, a carrier medium arrangement carrying and / or storing a program product as described herein is considered. An information system comprising, and / or connected or connectable, to a 550 radio node is also disclosed.

[0074] Brief description of the drawings

[0075] The drawings are provided to illustrate concepts and approaches described herein, and are not intended to limit their scope. The drawings comprise:

[0076] Figure 1, showing schematically a bi-static sensing scenario; 555

[0077] Figure 2, showing an exemplary signalling scenario;

[0078] Figure 3, showing another exemplary signalling scenario;

[0079] Figure 4, showing another exemplary signalling scenario;

[0080] Figure 5, showing yet another exemplary signalling scenario;

[0081] Figure 6, showing an exemplary setup using sensing synchronisation signalling; 560

[0082] Figure 7, showing an exemplary scenario;

[0083] Figure 8, showing an exemplary processing setup;

[0084] Figure 9, showing an exemplary processing setup;

[0085] Figure 10, showing an exemplary processing setup;

[0086] Figure 11, showing an exemplary wireless device; and 565

[0087] Figure 12, showing an exemplary network node.

[0088] Detailed description

[0089] Joint communication and sensing (JCAS) is emerging as one of the use cases in future wireless cellular communication such as 6G. In one approach, it may be considered using cellular communication (radio) nodes (base stations / UEs) to sense the environment by 570

[0090] P111680W001 16 / 88 either using the communication-specific signals and / or dedicated sensing signals, and provide information such as location, shape, speed, etc., of the objects in the surrounding.

[0091] Some of the possible applications of sensing using cellular communication systems are traffic monitoring and crash avoidance, gesture / motion detection, presence detection of objects or persons, vital sign detection, environment mapping, particle / pollution detec- 575 tion, etc. In general, joint communication and sensing may comprise and / or be based on utilising radio nodes for a communication network for sensing and / or radar operation, e.g. sharing radio circuitry and / or antennas and / or resources.

[0092] Tighter integration of communication and sensing may be provided. By reusing existing macro infrastructure, sensing can be added at low cost. Sensing can be using both to 580 improve network performance and to add new features such as traffic monitoring and surveillance. If the same hardware is used for radar and communication, performance and capacity of both systems may suffer. Radar signalling may be considered sensing signalling and vice versa in this discussion. For example, to monitor a traffic intersection, detect approaching vehicles and their speed, a large part of available resources may be 585 used for radar operation, lowering resources available for communication. Approaches described herein facilitate efficient operation of joint communication and sensing, with limited impact of sensing operation on communication capabilities.

[0093] Sensing can be done either using a single node, i.e. the transmitter and receiver are co-located and / or associated to the same radio node (mono-static) or multiple nodes, in 590 which case the transmitter (s) and receiver(s) may be in different locations (multi-static); in some variants of multi-static approaches, one or more nodes may be have transmitter and receiver and / or may operate for transmitting and receiving. One particular challenge with the mono-static scenario in joint communications and sensing is that if the same radio node is used for simultaneous transmission and reception, then it has to be capable of 595 full-duplex communication (the received signals will be shifted in time to the transmitted one, but usually overlap in time). This may be particularly challenging, since the received signal levels in a cellular communications may be lower than the transmitted signals by several orders of magnitude; reception of such signals may be facilitated by certain approaches or designs considered to reduce interference. In a mono-static radar setup, 600 simultaneous transmission and reception (and thus full duplex) is unavoidable if it should be possible to detect targets close to the base stations (targets far enough away may be less challenging from this point of view since the echo (reflected signal) may arrive after the BS stopped transmitting). Bi-static sensing may represent a scenario with one transmitter and one receiver. 605

[0094] In a mono-static radar, transmitter and receiver nodes may be collocated (e.g., on and / or

[0095] P111680W001 17 / 88 associated to the same node). The transmitter sends a waveform that is reflected by the environment and targets. These reflections are received by the receiver and processed, e.g. by the receiver or another connected entity, to obtain information about the environment and targets. 610

[0096] A radar pulse that spans one or multiple OFDM symbols would allow an easy integration of radar into the communication system. For example, for NR 30 kHz numerology, the OFDM symbol duration (including cyclic prefix) is approximately 36μs. A radar pulse spanning a single OFDM symbol duration would have the same length. A round trip time of 36μs corresponds to single-way distance of 5.4 km. For objects closer than 5.4 km, the 615 echo would arrive while the transmitter still transmits the radar pulse. The reflected signal may be received in presence of strong self-interference (the transmitted signal that leaks into the receiver). A receiver capable of handling such self- interference is often called a full-duplex capable receiver. Full-duplex puts high requirements on the receiver and potentially also on the transmitter (e.g. linearity), especially for high transmit powers 620 where high self-interference cancellation is required.

[0097] In bi-static radar (and more generalised, for multi-static radar), transmitter and receiver are not collocated and the setup thus avoids problems outlined above for mono-static radar. Distance observations may be based on measuring the Time of Flight (ToF) from transmitter via the target to the receiver. In a simple case, where the signal is reflected 625 off the target and nothing else, all possible target positions for a measured ToF value are located on an ellipsis (in 3D: ellipsoid) with focal points given by transmitter and receiver location. To determine the target position, transmitter and receiver node location, ToF, and Angle of Departure (AoD) or Angle of Arrival (AoA) must be known. One of the angles is needed to determine the target location on the ellipse given by transmitter and 630 receiver location and ToF.

[0098] In order to accurately determine ToF, transmitter and receiver need to be accurately synchronized in time. This is may be one of the challenges for bi- and multi-static radar.

[0099] In multi-static radar, more than two nodes participate in the radar operation. For example, with one transmitter and three receivers, three ellipses can be determined and the 635 target is located where the three ellipses intersect each other. For multi-static radar, ToF observations may suffice to locate the target, and angle information may not be needed (but can be used to improve performance). In a communication network, there are several ways to do bi and multi-static sensing. Either the base stations or the UEs can act as sensing transmitters or receivers. Base station — UE links can be used in the downlink, 640 just as well as UE — BS links in the uplink, and BS — BS and UE — UE links.

[0100] The sensing receiver performs radar processing to estimate range and / or Doppler shift of

[0101] P111680W001 18 / 88 the target. In case the receiver has multiple antennas, it can also estimate the direction in which the target is. To estimate range, Doppler shift and direction to the user, the sensing receiver correlates the received signal with delayed and frequency shifted versions of the 645 known transmitted signal. The result of this correlation is a delay — Doppler profile. Note that in some application only estimating range or Doppler shift might be sufficient. To estimate the direction of the target, the delay — Doppler profiles of the different antennas are correlated with the steering vector of the array for different values of the incidence angle. The result of this correlation may be represented as a radar cube. A target, if 650 illuminated properly, creates a “peak” in a radar cube at the values corresponding to its range, Doppler shift and direction. Here, in this multi-dimensional function, a “peak” is a point in the function where the modulus of the function has a distinct maximum.

[0102] Observations of the range, Doppler shift and direction can thus be obtained by identifying where in the radar cube the peak of the target is. When observations from multiple sensing 655 receivers are available, these are fused to produce an estimate of the target position and velocity. The quality of these estimates may be characterized through the error covariance matrix.

[0103] In some applications, sensing may improve network performance and / or add new features such as traffic monitoring and surveillance. If the same hardware is used for radar and 660 communication, performance and capacity of both systems may suffer in comparison to using separated dedicated equipment for both. If, for example, a traffic intersection is monitored, to detect approaching vehicles and their speed, significant parts of the available resources (e.g., half) may be required for radar operation.

[0104] The available carrier or system bandwidth in 6G at high frequencies is expected to be 665 very wide, e.g. covering one GHz or more, in particular 5GHz or more. There are several regions with ~6GHz contiguous spectra (bandwidth) available for high frequencies (above 90 GHz).

[0105] Sensing, also referred to as active sensing, may generally refer to transmitting signalling and / or receiving reflection / s of this signalling, e.g. radar signalling and / or communica- 670 tion signalling; Sensing may comprise and / or be based on processing received (reflected) signalling to determine one or more properties of a target object, e.g. position and / or speed (total speed, or a component thereof, e.g. to direction of the receiver) and / or shape and / or size and / or velocity (total, or a component thereof) and / or surface structure and / or reflexivity of a reflecting object, e.g. based on one or more signalling characteris- 675 tics of the transmitted (radar) signalling and / or one or more signalling characteristics of the received (radar) signalling, and / or based on one or more changes and / or shifts and / or differences and / or delta (e.g., one value subtracted from another value) between one or

[0106] P111680W001 19 / 88 more signalling characteristics of the transmitted signalling and / or received signalling.

[0107] For a multi-static case, the receiving node may be informed about the one or more sig- 680 nailing characteristics, e.g. based on configuration (e,g, higher layer signalling like RRC signalling or MAC layer signalling, or Fl signalling, or X2 signalling, or physical layer signalling).

[0108] Sensing signal processing is described in the following. In active sensing, a signal or signalling like radar signalling is transmitted to probe the environment, and the received 685 reflections are used to estimate for example position and / or speed and / or velocity of the object / s in a range covered by the signalling. Depending on the required accuracy and range for the position and speed of the object / s, there are certain requirements on the duration, bandwidth, and periodicity of the signalling or signal to be used.

[0109] In a typical pulse radar, a sequence of wave- forms or symbols or signals (e.g., spreading 690 codes) with chip duration T and signal integration duration of Tintwith periodicity Trare transmitted for a duration Tf (there is one transmission or signalling occurrence in each Tr). The choice of these parameters determine range (sensing range, if waveforms are identical), range resolution, velocity or speed (speed or velocity range), and speed / velocity resolution for sensing targets. L and M may represent integer numbers (of 695 chips or symbols in a period corresponding to the periodicity, and number of transmission occurrences in Tf, respectively).

[0110] Depending on the use case, a sensing signal design may be tailored to meet fundamental requirements one or more of Range resolution (Rr) representing the minimum distinguishable distance between two objects; and / or (Unambiguous) range (Ru), representing the 700 maximum distance where an object can be located for (e.g., guaranteed, and / or within a desired error range) detection; and / or Speed or Velocity range (uM), representing the maximum range of speed or velocity of moving object that can be measured; and / or Speed or Velocity resolution (ur), representing the smallest change in the speed or velocity of the moving object that can be measured. 705

[0111] The parameters of a sensing signal (which in general may also be referred to as sensing signalling, or radar signal, or radar signalling) may include a bandwidth, like a minimum bandwidth, and / or a duration like a minimum duration of the sensing signal, and / or a a minimum and / or maximum repetition periodicity, and / or a minimum duration of the sensing frame (a time interval in which sensing signalling may be transmitted), may be 710 designed such above sensing requirement / s are met. Table 1 below shows the relationship between the sensing requirements and the sensing signal parameters, with c denoting the speed of light, fcrepresenting the carrier frequency.

[0112] P111680W001 20 / 88 Table 1

[0113] Required bandwidth

[0114] Minimum gap between sensing signals Trmin C

[0115] 715 Maximum gap between sensing signals Trrriax €■ / ^fc^u

[0116] Required sensing frame duration Tf= c / 2fcv

[0117]

[0118] r

[0119] At the receiver, the reflected signal (e.g., reflected from one or more objects and / or from the surrounding) is received, and may be matched and / or filtered with the transmitted wave-form to give the delay (e.g., representing the distance of the object), and / or the phase rotation between consecutive wave forms, e.g. representing the Doppler shift due to the movement of the object. In general, the above-mentioned signal generation and 720 receiver processing may be common to all types of sensing methods and signals, and is not limited to a pulse radar. In a joint communication and sensing scenario, the choice of wave-form may depend on what wave-form is more suitable for both communication and sensing, although this is not a requirement, and the wave-forms for the two systems may be different. The following description of receiver processing is independent of the wave725 form type and is equally applicable to wave-forms, as well as any typical communication wave-form such as OFDM, DFT-s-OFDM, etc. As one example, the wave-form may comprise, and / or be based on, and / or represent, and / or be one or several OFDM or DFT-S-OFDM symbols ( or even sub-symbols), and / or block symbols, as it is the common wave-form used in most of the existing wireless access links (used for wireless and / or 730 cellular communication). A sensing signal may be based on OFDM symbols, in particular a train of OFDM symbols as sensing signalling; such train may be repeated a plurality of times, e.g. according to a periodicity, e.g. in one or more sensing frames. A train of symbols may represent a sequence of symbols, each of which may carry and / or represent a sequence of modulation symbols (e.g., for a OFDM based wave-form), which may be 735 mapped to frequency domain; each symbol may carry the same or a different sequence.

[0120] In some cases, a sequence may be mapped over multiple symbols, e.g. frequency first.

[0121] A common receiver processing may comprise and / or be based on performing an FFT per sequence occurrence, e.g. a train of symbols, for example transforming delay domain into sub-carrier (frequency) domain, and an IFFT per sub-carrier across the sequence 740 occurrences, for example transforming time-domain into Doppler domain. Then peaks, e.g. all peaks, beyond a threshold may be identified, and the delay and Doppler values associated with each peak (representing a target) may be considered corresponding to delay and velocity or speed of the target.

[0122] The communication nodes involved in sensing may be UEs, base stations, or a combi745 nation thereof, including base-station transmission of signal for sensing, UE reception of signal for sensing; and / or UE transmission of signal for sensing, base-station reception

[0123] P111680W001 21 / 88 of signal for sensing; and / or base-station transmission of signal for sensing, base-station reception of signal for sensing; and / or UE transmission of signal for sensing, UE reception of signal for sensing. For cellular communication, such as according to 5G or 6G, this 750 could mean that the sensing signal can be a DL reference signal, or a UL reference signal, a sidelink reference signal. Also the sensing signal can be any of the existing signals, such as DL positioning reference signal (PRS), CSI-RS, DM-RS; and UL sounding reference signal (SRS), a new sensing / positioning specific signal, or the communication signal itself.

[0124] Combinations of these signals may also be used. Although sensing is viewed mostly as es- 755 timating channel based on known reference signals, it is possible to perform sensing based on data. In this case, either data is known at the receiver (e.g. mono-static scenario) or it has to be decoded first so that the channel can be estimated subsequently.

[0125] ISAC (integrated sensing and communication) is thought to become an important part of 5G advanced and / or 6G. To enable as much reuse of the BS hardware as possible, 760 an OFDM based waveform may be assumed to be utilised. Radar can be categorized as mono-static or bi / multi-static radar.

[0126] Figure 1 shows an example bi-static radar application. It is assumed in this example that both end BSs (base-stations representing transmitter and receiver of sensing signalling, respectively) comprise and / or utilise large antenna arrays and operate in 3GPP TDD 765 bands. Thus each end (or end point) may form narrow transmit and receive beams. By using the beam directions of receiver and transmitter, combined with the propagation delay, accurate positioning of the object / target of the sensing signalling can be derived.

[0127] If needed, more TX& RX BSs can be included in the radar measurements to get better position accuracy (e.g., going from bi-static to multi-static with more than 2 participants). 770

[0128] Performing multiple measurements in time and detecting the phase difference between successive measurements may be considered, which may facilitate the speed of the object can be detected (e.g., by calculating the Doppler-shift of the reflected signal). Detection of moving objects may be easier than static objects, since it may be easier to filter out and separate a moving object from all static reflections (also called clutter noise or simply 775 clutter). In many cases, moving objects may be also targets of more interest in radar sensing than stationary objects.

[0129] To enable accurate range and Doppler / speed measurements, very good synch between receiver and transmitter is desirable. The synch requirements on time alignment and frequency alignment for RF phase stability are usually more stringent than what is available 780 in a BS by default. Also, the presence of phase noise within TX and RX may make it especially challenging to detect an object with low Radar Cross Section (RCS) and low

[0130] P111680W001 22 / 88 speed in the presence of e.g., a nearby building with large RCS.

[0131] By assuming that there is a LOS path in-between TX and RX BS, that signal can be used as time and RF phase reference which can relax synch requirement several orders of 785 magnitude. Using the LOS signal as RF phase reference avoids adding costly and complex synchronisation methods like expensive oscillators to the BSs and mitigates delay and RF phase uncertainties in the BS TRX chains while still enabling accurate sensing. A characterized and stable NLOS path can also be used as a time and phase reference. In general, sensing synchronisation signalling may provide a time reference and / or phase 790 reference, e.g., for processing sensing signalling.

[0132] If there is an LOS reference signal path, the dynamic range of the receiving base station can easily become a performance bottleneck due to a strong LOS component, e.g., in terms of high PAPR. The signal being reflected at the object will likely have much higher path loss than the LOS component. The reflected signal may have two or more propagation 795 losses, so the path loss will be proportional to d12x d22(dl and d2 are the distances TX-target and target-RX, respectively) whereas the LOS path loss is proportional to d2(d is the LOS distance between TX and RX). Also, the reflected path loss depends on the object size, RCS (radar cross section). The receiver thus may need to manage two input signals with very different signal level. Difference in path loss could approach lOOdB. 800

[0133] There are multiple potential dynamic range bottlenecks in the receiver, for example the analogue front and ADC. Another bottleneck may be digital radar signal processing.

[0134] Assuming the BS receiver applies digital BF (beamforming), a first bottleneck may depend on the signal level at each antenna input. This first bottleneck may be overcome by having good beam directivity in the transmitter end. A second limitation may arise in beam- 805 domain, and may be mitigated by improved RX beamforming. Thus, both dynamic range limitations may be improved by beamforming. Beamforming accuracy in a BS is normally limited by how good one can calibrate the antenna array.

[0135] Antenna calibration of an AAS (Advanced Antenna System, e.g. active and / or adaptive) BS may be performed in several ways. One method may comprise sensing or injecting a 810 signal at each antenna, and measure the relative gain / phase relations. Another method is to use the mutual coupling between the antennas and do loopback measurements between transmit and receive ports. These calibration methods are dimensioned to give good enough performance in communication mode and the accuracy can be pretty relaxed without loss of communication performance. They may be considered part of, and / or a 815 representing of a form of channel sounding.

[0136] If there is a lack of LOS reference path / channel, it may be unclear what signal path

[0137] P111680W001 23 / 88 to use as the reference path. Ideally, the reference path should be a clear path coming from a single direction and having a strong single tap characteristic in time domain with zero Doppler shift. A reflected path can be of multipath nature, giving it time dispersive 820 characteristics which may limit its applicability as reference; close in reflections could also be an issue for a LOS reference path. Also, a reflected path may be time variable in the sense it may introduce Doppler-shift, which may also is problematic for the reference path.

[0138] In general, a reference channel, and / or channels of a set of reference channels, may be 825 determined to reach, and / or be based on, a threshold for one or more parameters, e.g., pertaining to Doppler-shift, and / or time- variability, and / or time dispersion, and / or number of reflections, and / or path-loss. A threshold may represent a maximum value, e.g., such that the parameter and / or characteristic of the channel are below the threshold (a minimum may be used, depending on parametrisation). For example, a channel of 830 the set of channels, and / or a reference channel, may have a path-loss that is below a maximum path-loss, or have a minimum ratio of power coming through after path-loss.

[0139] Alternatively, it may be based on a relative and / or absolute measure, e.g., pertaining to the strength of a single tap characteristic, and / or Doppler-shift, and / or signal quality and / or signal strength and / or delay and / or time dispersion. For example, a pre-defined 835 and / or configured or configurable number NSC of sounded channels may be determined to be part of the set, e.g., based on a relative or absolute measure (e.g., the NSC with the strongest single tap, and / or lowest Doppler-shift, etc.). NSC may be an integer number of 1 or larger.

[0140] Each BS pair in the field (performing bi-static sensing) may have different channel condi- 840 tions which depend on site location, antenna placement and environment between them.

[0141] In some cases, the channel may show time varying properties which may make it hard to a priori define how to use the channel as bi-static reference path. Thirdly, the radar sensing signal may be beam-formed in both TX and RX side, meaning that the signal strength of an LOS or a reflected reference path may be unpredictable, and may in some 845 cases be too weak to receive accurately.

[0142] Use of a separate reference signal (sensing synchronisation signalling) which is multiplexed to the actual radar sensing transmit signal (sensing signalling) may be optimised, e.g., by multiplexing in an orthogonal way; the sensing signalling then may be received and de-multiplexed at the receiving end. The multiplexing can for example be done by means 850 of using separate sub-carriers for reference signal and for sensing signal (multiplexing in frequency domain).

[0143] In general, a channel may be characterized between the two BS involved in the bi-static

[0144] P111680W001 24 / 88 radar operation, e.g., based on channel sounding. The characterization may be performed using a uni-directional or a bi-directional channel sounding between the two BSs. Channel 855 sounding (e.g., in mono-static or multi-static scenario) may in general be used to characterize the spatio-temporal channel, and providing / or information on how to set (e.g., optimal) transmitting and receiving parameters for each direction in order to achieve the best reference path conditions. Parameters may be used for pre-coding the signal at the transmitter end, and to process the signal at the receiving end. Parameters (like transmis- 860 sion parameters, which may be the same or essentially similar between beams for sensing signalling and sensing synchronisation signalling and / or for sounding) may for example comprise, and / or pertain to, one or more of beamforming weights, and / or time-domain filtering, and / or polarization co-phasing factors.

[0145] These parameters may be determined based on, and / or from the channel sounding, and / or 865 may be used to transmit and / or shape the radar / sensing signalling, e.g., to minimise interference with the reference signal path / channel (e.g., ’’nulling” both at transmitter and receiver side). Since the reference signal / sensing synchronisation signalling and radar / sensing signalling may be orthogonal, the receiver may find undesired signal leakage between beams, and may adjust the weights in its beamforming to deepen the nulls 870 in both the reference beam (transmission and / or reception beam for sensing synchronisation signalling) and the object beam (transmission and / or reception beam for sensing signalling), e.g., during the run-time radar / sensing signalling.

[0146] With this, a separate reference path / channel may be created which may be independent of the radar / sensing signalling, and hence a stable and continuous reference signal path 875 or channel may be maintained independently of the radar / sensing signal due to different object locations. For processing and / or transmitting and / or receiving the reference signal (also referred to as sensing synchronisation signalling or reference signalling) the same physical transmitting and receiving chains of the respective radio node / BS may be used, which may facilitate use as phase and / or time reference, in particular as RF phase and 880 time reference, without or with limited compromised performance.

[0147] In general, transmission and / or reception of sensing synchronisation signalling and / or sensing signalling may be on both and / or two polarisations (two orthogonal polarisations).

[0148] In particular by transmitting orthogonal signals simultaneously in both polarizations, and receiving in both polarizations, accurate relative characterization of both co-polarized 885 and both cross-polarized channel responses may be be obtained. This may facilitate determining a combination weights of transmit polarizations and combination weights of receive polarizations, which may result in the shortest relative delay, which may provide the least effect of close-in reflections, or if such reflections are not a problem, may have

[0149] P111680W001 25 / 88 the distinct single-tap channel property. 890

[0150] A polarimetric radar scheme may be applied to the radar / sensing signalling, which may comprise and / or represent transmitting orthogonal signalling in the two polarizations, and / or receiving in two polarizations, e.g., to characterise targets both in terms of copolarized and cross-polarized responses. If the radar units (radio nodes / BS) may rotate in polarization with respect to each other, the polarized reference signal measurements 895 may serve as a reference for the polarimetric radar measurement.

[0151] A pool (or set) of available or possible and / or multiple and alternative reference paths or channel may be characterised and / or determined, e.g., allowing comparing and selecting the best over time. As one example, a characterised LOS reference path (generally also referred to, and / or represented as, reference channel) may be used to evaluate different 900 potential alternative NLOS paths, different reference paths may be compared to evaluate potential changes in one reference path making it less suitable as reference. Switching between a first and a second reference path alternative (using a difference channel from a set of reference channels) may be done seamlessly because the characteristics of the multiple reference paths may be decided in and / or based on the channel sounding, and 905 may therefore be compensated for. Characteristics of different channels in the set of channel may for example be different regarding one or more of path loss, and / or path delay, and / or polarization co-phasing, etc.

[0152] Separate signals for reference and radar sensing purposes may be utilised. Reference signalling and radar / sensing signalling (in general, sensing signalling may be referred 910 to as radar signal or radar signalling or sensing signal or radar / sensing signalling or radar / sensing signal) may be multiplexed and / or orthogonalised at the transmitter end, and / or de-multiplexed at the receiving end. In general, receiving and / or processing sensing signalling and / or sensing synchronisation signalling may comprise, and / or be based on demultiplexing the signalling / s. 915

[0153] A signal path for reference signal (also represented as, or referred to as, reference channel) and for radar sensing signal may be precoded at transmitting side and extracted at receiving side in different ways, so that they may form independent channels. Pre-coding and extraction may pertain to, and / or may be for beamforming weights, polarization co-phasing, time windowing etc. 920

[0154] Optimised parameters for precoding and extraction parameters may be found from a separate uni-directional or a bi-directional channel sounding between two BS involved in bi-static radar sensing. Multiple reference path candidates (channels of the set of reference channels) may be found from the channel sounding, and may be used as a pool or

[0155] P111680W001 26 / 88 set of alternative reference paths / channels. In the case one reference path performance is 925 compromised during run-time radar signalling, this can be easily detected and a switch to the alternative reference path can be done seamlessly. The formed reference path may be used as time and RF phase reference to improve the range accuracy and mobility detection during bi-static sensing. It may further enable longer integration times, which may improve clutter suppression and detection of objects with smaller RCS. Both channel 930 sounding and radar sensing signals may be transmitted with orthogonal waveforms in the two polarizations. This may allow the polarization responses to be characterised for the reference path so that a cleaner channel response can be achieved, and the polarimetric response of the target may also be obtained. By using orthogonal signals for sensing and reference, the signal leakage can be measured in the receiver, and to minimise it, deeper 935 nulls may be formed in both sensing and reference beam by adjusting the beamforming weights. When radio nodes / units are used which are not fixed in orientation, the polarimetric reference signal measurement may also provide a reference for polarimetric sensing, so that if one radar unit rotates in polarisation with respect to the other, this is not confused with a change in object polarisation response. 940

[0156] Approaches described herein may facilitate improving in particular multi / bi-static radar performance by providing a reliable, clean and stable reference signal path, which may be independent of the radar sensing signal. Robustness of in particular a bi-static radar may be supported, e.g., by providing alternative reference signal paths (channels of the set of reference channels), e.g., with seamless switching between reference paths when needed 945 during run-time radar signalling. Alternative reference signal paths may also usable to avoid blindness for an object close to one of the reference paths. Conditions for reference path synchronisation in NLOS condition may be provided. LOS synchronisation in bi-static radar sensing scenario may be improved by avoiding dynamic range bottlenecks in the receiver. Cross- link interference in radar sensing scenarios may be reduced, and / or 950 cross link interference when performing Radio Interface Based synchronisation (RIBS) may be reduced. Cleaner reference channel response may be achieved by optimizing the polarisation. Deeper nulls in the reception beams, for both sensing and reference, may minimise interference between sensing and reference signal. Polarimetric sensing may be possible even when a radar unit (radio node) rotates / changes polarisation. 955

[0157] A reference path / channel may provide a RF phase reference for frequency offset and / or may provide phase noise mitigation, and / or may provide a delay reference for timing.

[0158] Criteria for a ’’good” reference path may be considered, which may be criteria and / or parameters based on which channels of the set of reference channels may be determined and / or selected (’’good” channels or paths). One or more such criteria may for example 960

[0159] P111680W001 27 / 88 pertain to Single-tap channel (e.g., strength), and / or no or low Doppler shift, etc.

[0160] A sensing transmitter (radio node operating as TX in bi-static sensing) may transmit sensing synchronisation signalling and sensing signalling. To facilitate the synchronisation state obtained via the sensing synchronisation signalling being valid when the sensing signalling is received, both signallings may be transmitted close to each other (e.g., in 965 time and / or frequency), e.g., within the same subframe or slot or sub-slot, and / or the same sensing time interval (e.g., a number of symbol time intervals of 1 or larger, or 4 or larger, or 8 or larger, or 16 or larger, or 32 or larger); the first time interval and the second time interval may be combined to provide the sensing time interval, and / or on the same carrier and / or bandwidth part and / or frequency range, and / or with overlapping first and 970 second frequency intervals.

[0161] For example, if phase noise should be estimated based on the sensing synchronisation signalling, these two signals may be transmitted close to each other in time- and frequencydomain. One possibility is to multiplex both signals in frequency-domain. In case of a multicarrier-based system (such as OFDM, DFTS-OFDM, OTFS) both signals could be 975 transmitted in the same symbol, using different frequency combs (differing in terms of being shifted), as shown exemplarily in Figure 2. In the shown, example a comb-2 is used, larger comb-distances can be envisioned as well. Sensing synchronisation signalling and sensing signalling may span the same or different bandwidths. This setup has the advantage that both signallings are transmitted close to each other in time and frequency. 980 Closeness in time may provide that the synchronisation state obtained via the sensing synchronisation signalling is still valid during the sensing operation. Due to the frequencydomain interleaving between sensing synchronisation signalling and sensing signalling, phase noise may be be estimated / compensated for based on the sensing synchronisation signalling, and detrimental effects may be mitigated. 985

[0162] An alternative or additional possibility to separate sensing synchronisation signalling and sensing signalling is to use Frequency Division Multiplex (FDM) as shown in Figure 3. While the two signallings are still close in time (and thus the synchronisation state obtained via the sensing synchronisation signalling should still be valid during sensing) they are separated in frequency-domain. This setup may be less preferred when also phase 990 noise should be estimated / compensated. Separation in FDM does not necessarily require a multicarrier-based system, but works even for single-carrier-based systems.

[0163] Yet another (alternative or additional) possibility is to separate sensing synchronisation signal and sensing signal in code domain. For example, if a Zadoff-Chu sequence is used for both sensing synchronisation signalling and sensing signalling, a different linear phase 995 ramp (if the Zadoff-Chu sequence is applied in frequency domain, e.g. across sub-carriers

[0164] P111680W001 28 / 88 in a multicarrier system) could be applied to sensing synchronisation signalling and sensing signalling. If the Zadoff-Chu sequence is applied in time-domain (which works for both a multicarrier- and single-carrier-based system), a different cyclic shift could be applied to both signalling. Both designs are examples where sensing synchronisation signal and 1000 sensing signal would be orthogonal to each other. If for example long enough different m-sequences or Gold sequences are used, the two signalling would be sufficiently separated to be considered orthogonal. Sensing synchronisation signalling and sensing signalling are close in time- and frequency and can therefore be used for both synchronisation and phase noise estimation / compensation. 1005

[0165] If different beam forming (transmit and / or receive) should be applied to sensing synchronisation signalling and sensing signalling (which may be done typically, e.g., a narrow beam for a sensing synchronisation signalling) a beam forming architecture which enables independent beam forming of two signals may be needed. In communication, such a beam forming architecture is often referred to as digital beam forming. A drawback of trans- 1010 mitting sensing signal and sensing synchronisation signal at the same time may be that this may increase Peak to Average Power Ratio (PAPR). Even if sensing synchronisation signalling and sensing signalling on its own have low PAPR, the superposition of both signals has higher PAPR. Lowering the signal power of the synchronisation signalling versus the sensing signalling may reduces this problem. 1015

[0166] Another alternative or additional possibility to separate sensing synchronisation signalling and sensing signalling is to transmit them at different times, see Figure 4. Since sensing synchronisation signalling and sensing signalling are transmitted at different times, PAPR may remain low if sensing synchronisation signalling and sensing signalling have low PAPR. This setup may allow easy handling of large differences of received power 1020 between sensing synchronisation signalling and sensing signalling, since they are transmitted at different times. Changing the receiver setting may be performed carefully, e.g., to avoid phase-shifts. The time separation may be small between both signallings, so that the synchronisation state obtained from the sensing synchronisation signal is valid during sensing operation. In Figure 4, both signallings are adjacent in time; depending 1025 on the dynamics in the system, larger separations may be used, e.g., covering one or more symbol time intervals. If the sensing synchronisation signalling is also to be used by the receiver to compensate for phase noise, a smaller separation in time may be needed compared to the case when the sensing synchronisation signalling is only used for time and / or frequency synchronisation, since phase noise typically changes quicker in time. 1030

[0167] Separation in time may accommodate use of simple beamforming architectures that can only generate a single beam at a time, such as analogue beamformers, since sensing syn-

[0168] P111680W001 29 / 88 chronisation signalling and sensing signalling are transmitted / received at different times.

[0169] To maintain the same overhead as multiplexing sensing synchronisation signal and sensing signal into a single symbol, it may be considered to use half-symbols when multiplexing 1035 sensing synchronisation signal and sensing signal in time, see Figure 5. One possibility to create half-symbols is to transmit sensing synchronisation signal and sensing signal using a sub-carrier spacing which is twice as large as the nominal sub-carrier spacing, since doubling the OFDM sub-carrier spacing reduces the OFDM symbol duration by a factor two.

[0170] If the underlying frame structure has a slightly irregular structure (e.g. as in NR) the 1040 main symbol durations without cyclic prefix of sensing synchronisation signal and sensing signal are half of the main symbol duration without cyclic prefix of a nominal symbol (but if the cyclic prefix is counted into the symbol duration the ratio is not necessarily exactly half).

[0171] Figure 6 shows signal processing related to the sensing synchronisation signal. In this 1045 example a comb separation between sensing synchronisation signalling and sensing signalling is assumed. The receiver separates sensing synchronisation signalling and sensing signalling and applies separate beamforming for each signal (not shown). Based on the sensing synchronisation signalling, the LOS path arrival time tref and the phase iprej may be determined. The phase of the impulse response

[0172]

[0173] (e.g., obtained via channel 1050 estimation from the received sensing signalling) may be corrected with the phase ipref (potentially averaged over multiple symbols containing sensing synchronisation signal), e.g., hsense[u] = h[n\

[0174]

[0175] x is formed. hsense[u] is then used in subsequent signal processing steps. The time of flight pertaining to target m (which may be used for range estimation of target m) may be obtained as Tsense[m] = isense[m] — tref + T^QS with isense[m] the 1055 estimated arrival time of the signal path corresponding to the target m, tref the arrival time of the LOS path, and T QS the propagation path of the LOS reference path (e.g. obtained via a map), TLQS = d os / co d os is the distance of the LOS reference path and c0is the speed of light (and / or obtained through an over the air round trip time observation e.g. through RIBS), respectively. If the reference path would be a suitable 1060 NLOS path, T QS would pertain to the propagation path (channel) of the NLOS path.

[0176] General criteria for a good synchronisation reference path or reference channel may comprise and / or pertain to a good signal level or quality or strength (e.g., SINR), and / or single tap property and / or stability over time. The signal being reflected at the object or target likely will have much higher path loss than the LOS synchronisation reference 1065 path. There are multiple potential dynamic range bottlenecks in the receiver. One being the analogue front and ADC. Another bottleneck is the digital radar signal processing.

[0177] Assuming the BS receiver applies digital BF, the first bottleneck may depend on the signal level (quality or strength) at each antenna input. This first bottleneck may be overcome

[0178] P111680W001 30 / 88 by lower power assigned for the LOS synchronisation reference signal and having good 1070 beam directivity in the transmitter end, e.g., to avoid strong power from the sensing signal into the LOS synchronisation reference path for all different sensing directions. The second may arise beam-domain and may be mitigated by improved RX beamforming. A good beam directivity for the LOS synchronisation reference path may also isolate it from unwanted reflections and increase isolation towards sensing signalling. Initial knowledge 1075 of the characteristics of the LOS synchronisation reference path (Time of Flight (ToF), spatial and path- loss) may be derived based on known locations of the radio nodes, and / or obtained through an over the air round trip time observation e.g., through RIBS.

[0179] An NLOS reference path may be considered. Since the (synchronisation) reference path or channel may be used to compensate for time errors, frequency offsets and phase noise 1080 in the TRX chains of the receiver and transmitter, e.g., error sources common for the synchronisation and sensing path, the channel for the synchronisation reference path should be stable over time. A NLOS synchronisation reference path reflecting from non-static objects (e.g. experiencing sway from wind) would hence not be a good candidate. For stability a NLOS synchronisation reference candidate path could be evaluated based on one 1085 or more of from known characteristics of a reflecting object, its installation and environment like for a purposely placed reflector, and / or comparison against a known stable LOS reference path, and / or comparison against another known stable NLOS reference path, and / or comparison against known static objects in the environment, and / or bi-directional measurements of the candidate NLOS channel, where changes in channel may be recip- 1090 rocal, while frequency offsets and phase noise in TRX chains may be anti-reciprocal.

[0180] In general, a channel or path may be considered for, and / or determined to be part of, the set of reference channels based on one or more criteria, e.g., based on a stability evaluation, e.g., based on a comparison with one or more other channels and / or paths, e.g., one or more LOS paths and / or channels, and / or one or more reference NLOS paths 1095 and / or channels, and / or one or more paths or channels considered stable and / or unstable.

[0181] Stability evaluation over time may, e.g., also detect if a reflector has been moved (deliberate or by mistake). A comparison between reference paths with different spatial properties could also be used as a measure to detect phase instability caused by mast sway (certain paths could be more affected dependent wind direction). Multiple and alternative NLOS 1100 synchronisation reference paths could be characterized allowing comparing and selecting the best over time both from above mentioned stability considerations, but also related to sensing object locations (for improved isolation between sensing and synchronisation signals), and / or potential interference / jamming / blocking of the synchronisation reference signal. Switching between LOS-NLOS synchronisation reference paths over time based on 1105

[0182] P111680W001 31 / 88 reference path quality evaluation could also be an option. As for LOS synchronisation reference path, good beam directivity for the NLOS synchronisation reference path will also isolate it from unwanted reflections but also here to manage the increased pathloss. Also due to its higher pathloss, a higher transmit power for the synchronisation reference signal may be required compared using a LOS synchronisation reference path. Initial know!- 1110 edge of the characteristics of the NLOS reference path (Time of Flight (ToF), spatial and pathloss) may be derived based on known locations of the reflecting object (could e.g. be a dedicated reflector placed specifically tailored for the purpose) and TX / RX nodes or obtained through an over the air round trip time observation, e.g., through RIBS.

[0183] Channel sounding may be considered, e.g., to comprise and / or being based on channel 1115 estimation for the reference path / s; it should be noted that a number of paths may be sounded, one or some or all of which may be determined to be reference channels and / or to be members of the set of reference channels; in some cases, some sounded paths may not be considered as such members, e.g., based on one or more criteria such as criteria for a ’’good” reference channel or path. The channel sounding may resolve spatial and / or 1120 temporal and / or polarisational characteristics of the channel or path between two TRPs and / or radio nodes, and / or for one mono-static radio node. Additionally, the channel sounding may be used to power control the reference signalling, e.g., for best reception at the receiver side. For example, if there is a LOS path, the synchronisation sensing signalling may be transmitted with a lower or low transmission power, e.g., so that it does 1125 not exceed receiver dynamic range; in a NLOS scenario, more power may be allocated for the reference path and / or synchronisation sensing signalling.

[0184] Channel information determined based on channel sounding may match the needs of the reference path signal transmission and reception. The signal may be generated by a narrow beam in both transmit and receive, giving the highest beamforming gain, but 1130 also combinations of wide beam transmission and narrow beam reception can be used (or vice versa). Narrow or wide may refer to angular size, e.g., in horizontal and / or vertical direction. Narrow may in general refer to 60 degrees in angular size or less, or 45 degrees or less, or 25 degrees or less, or 10 degrees or less, or 5 degrees or less. Wide may pertain to 90 degrees or more or 120 degrees or more, or in general wider than a narrow 1135 beam according to one of the parameter values. Thus, a 55 degree beam may be wide in comparison to a 20 degree beam.

[0185] Channel sounding can be done in multiple ways, it may comprise and / or be based on one or more of:

[0186] • (1) transmitting orthogonal signals, e.g., per transmit antenna (antenna domain) 1140

[0187] P111680W001 32 / 88 and / or receiving in antenna domain, this may give a full resolution channel observation that can be transformed into spatial properties by means of, e.g., DFT processing. Limitation may occur due to insufficient link budget; and / or

[0188] • (2) sweeping a narrow transmit beam and receiving in antenna domain (or vice versa). In this way a full channel response may be found with additional beam- 1145 forming gain from beam sweep, which improves link budget. More time may be consumed due to sweeping.

[0189] • (3) sweeping a narrow transmit and a narrow receiving beam. This may have a good potential link budget due to full utilization of beamforming gain, but may be very time consuming due to many TX / RX beam combinations; and / or 1150 • (4) a hybrid method, which may comprise transmitting a wide beam, and receiving with a narrow beam or receiving in antenna domain. This way, an estimate of the channel at the receive antenna may be achieved. This method may require a two- stage (dual-directional) measurement in which both radio nodes act as the receiver, so that the channel estimate from both sides can be combined into one full channel. 1155

[0190] In these options, the signals per polarization may be orthogonally encoded and decoded in order to fully resolve the polarimetric properties of the channel. Options may be used in combination, e.g. using 1 for a coarse directional estimates, and then using 2 or 3 for refinement. The channel between two TRPs preferably may be reciprocal, the same in both directions, as indicated in Figure 7. Channel estimates in both directions then 1160 may give the same response. Still, a dual-directional channel sounding may be done to improve accuracy. Note that the channel as measured by the radios involved is reciprocal only if the radio chains involved are precisely calibrated for reciprocity. Of course, for accurate spatial and characterization the radio chains need to be calibrated in TX and in RX direction separately as well. 1165

[0191] From the estimated reference channel (determined / estimated based on the channel sounding), a decision or determination about what spatial, temporal and polarimetric parameters to apply to achieve the best reference channel may be performed, e.g., by the radio node and / or a scheduler thereof. This may include which beamforming (beam) direction to use on TX side, and what beamforming direction, time windowing and polarization 1170 combination to use on the RX side. These may be considered transmission parameters.

[0192] Figure 8 shows exemplary signal processing blocks that may be involved in the channel sounding. Radio 1 (a transmitting radio node) may transmit orthogonal reference signalling on polarization 0 and 1. The transmitted signalling travels through the channel h

[0193] P111680W001 33 / 88 and arrives at the receiving antenna on radio 2 (receiving radio node). Both transmitted 1175 signals are detected at the receiver using the Matched Filters, so that all 4 polarization combinations are detected. The best or a good enough combination of the B2A, A2B as well as amplitude scaling (ampl), delay and phase compensation may be determined, e.g., to optimise the sum of all signals into a resulting signal Sr. Optimisation may refer to achieving the best condition / s for usage as a reference signal (e.g. highest SNR, 1180 single-path channel). The amplitude, delay and phase scaling + summing can be seen as a Maximum Ratio Combining (MRC) scheme. For reduced complexity and improved robustness, it may be beneficial to apply a selection scheme instead as shown in Figure 9.

[0194] Here, only the best polarization is chosen for the resulting signal Sr. It can be noted that in this scheme, it is possible to omit transmitting on one of the polarizations, StO or S / l. H85 Combinations of the two examples may be used, e.g., such that only the polarizations that pass some criterion are combined (summed). This criterion can be for example pertain to received power, multipath profile, delay.

[0195] A further simplification can be done by using same beamforming for both polarizations as shown in Figure 10. In this case, the individual polarizations are still resolved, but both 1190 polarizations are beamformed in the same way in both TX and RX side. This reduces the search space considerably, but may not give the optimal polarization combination.

[0196] Both full polarization can be used as shown in Figure 7 and also the selection scheme can be used. When deciding the reference channel (or the set of reference channels) paths may be filtered out or discarded that are of time varying nature (e.g., above a specified 1195 threshold in terms of time variability). This may be a difficult task for example if there is some reflection path from a parked truck. This path may be stable and a good reference path up until the truck drives away. Repetitive channel estimates and filtering may be considered, e.g., over long timescale of 1 minutes or longer, or 10 minutes or longer, or Ih or longer, e.g., to determine very stable paths to be used as reference path. Potentially, 1200 a priori knowledge about the environment may be used, for example knowledge about positions of large buildings in the vicinity, or the use of dedicated reflectors placed in the environment.

[0197] Multiple reference signal paths may be determined. The described procedures facilitate using multiple reference path candidates between two radios (or even more radios, or for 1205 one in mono-static operation). The channel sounding procedure outlined herein may be performed to decide multiple distinct directions and / or polarisation combinations, which may use different amplitude, phase and delay alignment (referring to Figure 8); alternatively using different selection candidates that are useful for reference path purposes may be considered (referring to Figure 9). This may create a pool or set of multiple reference 1210 paths that can be used for the radar signalling. In the runtime radar processing, one of

[0198] P111680W001 34 / 88 these multiple reference paths may be used as reference path, e.g., until its quality falls below a certain criteria (e.g. received signal strength and / or quality or another criterium for ’’good” paths being not longer fulfilled), at which an alternative reference path can be chosen, e.g., from the set of reference channels or paths. Each different reference path 1215 or channel in the pool or set of reference paths or channels may have substantially different characteristics in channel attenuation, polarization properties and path delay. When switching between reference paths or channels, it may be required to compensate for this, e.g. by alternating transmitted power for the reference signalling, and / or applying an overall delay compensation of the reference path, so that the radar sensing functionality 1220 may operate seamlessly during the switch.

[0199] In the case of multi-static radar case (more than two radio nodes), reference signal paths (reference channels or paths) between the different radio pairs forming the multi-static radar system may be separately handled. Each radio pair procedure may be as described for the bi-static case. This can result in a B2A (TX beamforming) that generates multiple 1225 beam directions, each one optimized for the radio to be used as the receiving end. Also, different receiving end radios may require different transmit polarisations, such that both polarisations should be transmitted with orthogonal signals even if not every receiving radio may require them. A radio may be representative of a radio node, e.g., for TX and / or RX of sensing signalling and / or for communication operation and / or for sensing 1230 operation.

[0200] A priori information about the channel / s may be used to improve the performance and reduce time for the channel estimations. Knowledge about radio node position / s, and / or major reflector positions (e.g., large building or purposely-installed reflectors) may be used to narrow down the search space for the channel estimation. 1235

[0201] TX nulling of sensing signalling may be considered. Obtained information about the reference channel may be be used to null the strongest reference path directions in the sensing signalling beamforming. Since the transmitted sensing signalling may be much stronger than the transmitted reference signalling, this TX nulling may be useful to maintain a desired received signal dynamic range for both sensing synchronisation signalling 1240 and sensing signalling as received.

[0202] Sensing can generally be done either using a single node, i.e. the transmitter and receiver are co-located and / or associated to the same radio node (mono-static) or multiple nodes, in which case the transmitter (s) and receiver (s) may be in different locations (multi-static); in some variants of multi-static approaches, one or more nodes may be have transmitter 1245 and receiver and / or may operate for transmitting and receiving. One particular challenge with the mono-static scenario in joint communications and sensing is that if the same radio

[0203] P111680W001 35 / 88 node is used for simultaneous transmission and reception, then it has to be capable of full-duplex communication (the received signals will be shifted in time to the transmitted one, but usually overlap in time). This may be particularly challenging, since the received 1250 signal levels in a cellular communications may be lower than the transmitted signals by several orders of magnitude; reception of such signals may be facilitated by certain approaches or designs considered to reduce interference. In a mono-static radar setup, simultaneous transmission and reception (and thus full duplex) is unavoidable if it should be possible to detect targets close to the base stations (targets far enough away may 1255 be less challenging from this point of view since the echo (reflected signal) may arrive after the BS stopped transmitting). Bi-static sensing may represent a scenario with one transmitter and one receiver.

[0204] In a mono-static radar, transmitter and receiver nodes may be collocated (e.g., on and / or associated to the same node). The transmitter sends a waveform that is reflected by the 1260 environment and targets. These reflections are received by the receiver and processed, e.g. by the receiver or another connected entity, to obtain information about the environment and targets.

[0205] A radar pulse that spans one or multiple OFDM symbols would allow an integration of radar into the communication system. For example, for NR 30 kHz numerology, the 1265 OFDM symbol duration (incl. cyclic prefix) is approximately 36μs. A radar pulse spanning a single OFDM symbol duration would have the same length. A round trip time of 36μs corresponds to single-way distance of 5.4 km. For objects closer than 5.4 km, the echo would arrive while the transmitter still transmits the radar pulse. The reflected signal may be received in presence of strong self-interference (the transmitted signal that 1270 leaks into the receiver). A receiver capable of handling such self- interference is often called a full-duplex capable receiver. Full-duplex puts high requirements on the receiver and potentially also on the transmitter (e.g. linearity), especially for high transmit powers where high self-interference cancellation is required.

[0206] In some applications, sensing may improve network performance and / or add new features 1275 such as traffic monitoring and surveillance. If the same hardware is used for radar and communication, performance and capacity of both systems may suffer in comparison to using separated dedicated equipment for both. If, for example, a traffic intersection is monitored, to detect approaching vehicles and their speed, significant parts of the available resources (e.g., half) may be required for radar operation. 1280

[0207] Sensing, also referred to as active sensing, may generally refer to transmitting signalling and / or receiving reflection / s of this signalling, e.g. radar signalling and / or communication signalling. Sensing may comprise and / or be based on processing received (reflected)

[0208] P111680W001 36 / 88 signalling to determine one or more properties of a target object, e.g. position and / or speed (total speed, or a component thereof, e.g. to direction of the receiver) and / or 1285 shape and / or size and / or velocity (total, or a component thereof) and / or surface structure and / or reflexivity of a reflecting object, e.g. based on one or more signalling characteristics of the transmitted (radar) signalling and / or one or more signalling characteristics of the received (radar) signalling, and / or based on one or more changes and / or shifts and / or differences and / or delta (e.g., one value subtracted from another value) between one or 1290 more signalling characteristics of the transmitted signalling and / or received signalling. For a multi-static case, the receiving node may be informed about the one or more signalling characteristics, e.g. based on configuration (e,g, higher layer signalling like RRC signalling or MAC layer signalling, or Fl signalling, or X2 signalling, or physical layer signalling).

[0209] Sensing signal processing is described in the following. In active sensing, a signal or 1295 signalling like radar signalling is transmitted to probe the environment, and the received reflections are used to estimate for example position and / or speed and / or velocity of the object / s in a range covered by the signalling. Depending on the required accuracy and range for the position and speed of the object / s, there are certain requirements on the duration, bandwidth, and periodicity of the signalling or signal to be used. 1300

[0210] In a typical pulse radar, a sequence of wave- forms or symbols or signals (e.g., spreading codes) with chip duration T and signal integration duration of Tintwith periodicity Trare transmitted for a duration Tf (there is one transmission or signalling occurrence in each Tr). The choice of these parameters determine range (sensing range, if waveforms are identical), range resolution, velocity or speed (speed or velocity range), and 1305 speed / velocity resolution for sensing targets. L and M may represent integer numbers (of chips or symbols in a period corresponding to the periodicity, and number of transmission occurrences in Tf, respectively).

[0211] Depending on the use case, a sensing signal design may be tailored to meet fundamental requirements one or more of Range resolution (Rr) representing the minimum distinguish- 1310 able distance between two objects; and / or (Unambiguous) range (Ru), representing the maximum distance where an object can be located for (e.g., guaranteed, and / or within a desired error range) detection; and / or Speed or Velocity range (uM), representing the maximum range of speed or velocity of moving object that can be measured; and / or Speed or Velocity resolution (ur), representing the smallest change in the speed or velocity of 1315 the moving object that can be measured.

[0212] The parameters of a sensing signal (which in general may also be referred to as sensing signalling, or radar signal, or radar signalling) may include a bandwidth, like a minimum bandwidth, and / or a duration like a minimum duration of the sensing signal, and / or a

[0213] P111680W001 37 / 88 a minimum and / or maximum repetition periodicity, and / or a minimum duration of the 1320 sensing frame (a time interval in which sensing signalling may be transmitted), may be designed such above sensing requirement / s are met. Table 1 below shows the relationship between the sensing requirements and the sensing signal parameters, with c denoting the speed of light, fcrepresenting the carrier frequency.

[0214] Table 1 _ 1325 Required bandwidth BWmin— c / IRr

[0215] Minimum gap between sensing signals Trmin ^Ruf C

[0216] Maximum gap between sensing signals Trmax €■ / ^fc^u

[0217] Required sensing frame duration Tf= c / 2f

[0218]

[0219] cvr

[0220] At the receiver, the reflected signal (e.g., reflected from one or more objects and / or from the surrounding) is received, and may be matched and / or filtered with the transmitted wave-form to give the delay (e.g., representing the distance of the object), and / or the phase rotation between consecutive wave forms, e.g. representing the Doppler shift due 1330 to the movement of the object. In general, the above-mentioned signal generation and receiver processing may be common (and / or used similarly) to all types of sensing methods and signals, and is not limited to a pulse radar. In a joint communication and sensing scenario, the choice of wave-form may depend on what wave-form is more suitable for both communication and sensing, although this is not a requirement, and the wave-forms 1335 for the two systems may be different. The following description of receiver processing may be independent of the wave-form type and may be equally or analogously applicable to different wave-forms, as well as any typical communication wave-form such as OFDM, DFT-s-OFDM, etc. As one example, the wave-form may comprise, and / or be based on, and / or represent, and / or be one or several OFDM or DFT-S-OFDM symbols ( or even 1340 sub-symbols), and / or block symbols, as it is the common wave- form used in most of the existing wireless access links (used for wireless and / or cellular communication). A sensing signal may be based on OFDM symbols, in particular a train of OFDM symbols as sensing signalling; such train may be repeated a plurality of times, e.g. according to a periodicity, e.g. in one or more sensing frames. A train of symbols may represent a sequence of 1345 symbols, each of which may carry and / or represent a sequence of modulation symbols (e.g., for a OFDM based wave-form), which may be mapped to frequency domain; each symbol may carry the same or a different sequence. In some cases, a sequence may be mapped over multiple symbols, e.g. frequency first. A common receiver processing may comprise and / or be based on performing an FFT per sequence occurrence, e.g. a train 1350 of symbols, for example transforming delay domain into subcarrier (frequency) domain, and an IFFT per subcarrier across the sequence occurrences, for example transforming time-domain into Doppler domain. Then peaks, e.g. all peaks, beyond a threshold may

[0221] P111680W001 38 / 88 be identified, and the delay and Doppler values associated with each peak (representing a target) may be considered corresponding to delay and velocity or speed of the target. 1355

[0222] For cellular communications, such as 5G or 6G, sensing signalling and / or a sensing signal may comprise a DL reference signal, or a UL reference signal, or a sidelink reference signal.

[0223] Sensing signalling and / or a sensing signal may be any of the existing signals, such as DL positioning reference signal (PRS), CSI-RS, DM-RS; and UL sounding reference signal (SRS) or uplink DMRS, a new sensing / positioning specific signal, or a communication 1360 signal itself (e.g., control signalling or data signalling, e.g. on a PUCCH or PUSCH or PDCCH or PDSCH). Combinations of these signals may also be used.

[0224] Sensing may be based on estimating a channel based on known reference signals, in some cases sensing may be based on data. In this case, either data may be known at the receiver (e.g. mono-static scenario) or it may be be decoded first, so that the channel can 1365 be estimated subsequently. Communication may be based on (DFTS-)OEDM; OFDM based radar may be used to allow re-use of as much hardware as possible.

[0225] Figure 11 schematically shows a radio node, in particular a wireless device or terminal 10 or a UE (User Equipment). Radio node 10 comprises processing circuitry (which may also be referred to as control circuitry) 20, which may comprise a controller connected to a 1370 memory. Any module of the radio node 10, e.g. a communicating module or determining module, may be implemented in and / or executable by, the processing circuitry 20, in particular as module in the controller. Radio node 10 also comprises radio circuitry 22 providing receiving and transmitting or transceiving functionality (e.g., one or more transmitters and / or receivers and / or transceivers), the radio circuitry 22 being connected 1375 or connectable to the processing circuitry. An antenna circuitry 24 of the radio node 10 is connected or connectable to the radio circuitry 22 to collect or send and / or amplify signals. Radio circuitry 22 and the processing circuitry 20 controlling it are configured and / or adapted for cellular communication with a network, e.g. a RAN as described herein, and / or for sidelink communication (which may be within coverage of the cellular 1380 network, or out of coverage; and / or may be considered non-cellular communication and / or be associated to a non-cellular wireless communication network), and / or may be adapted or configured for sensing operation. Radio node 10 may generally be adapted to carry out any of the methods of operating a radio node like terminal or UE disclosed herein; in particular, it may comprise corresponding circuitry, e.g. processing circuitry, and / or 1385 modules, e.g. software modules. It may be considered that the radio node 10 comprises, and / or is connected or connectable, to a power supply. A DFE may be considered part of radio circuitry; an analog frontend may be associated to radio circuitry and / or antenna circuitry. Antenna circuitry 24 may comprise, and / or be connected or connectable, to an

[0226] P111680W001 39 / 88 antenna array or antenna arrangement as described herein. 1390

[0227] Figure 12 schematically shows a radio node 100, which may in particular be implemented as a network node 100, for example an eNB or gNB or similar for NR. Radio node 100 comprises processing circuitry (which may also be referred to as control circuitry) 120, which may comprise a controller connected to a memory. Any module, e.g. transmitting module and / or receiving module and / or configuring module of the node 100 may 1395 be implemented in and / or executable by the processing circuitry 120. The processing circuitry 120 is connected to control radio circuitry 122 of the node 100, which provides receiver and transmitter and / or transceiver functionality (e.g., comprising one or more transmitters and / or receivers and / or transceivers), and / or may be adapted or configured for sensing operation and / or communication operation. An antenna circuitry 124 may 1400 be connected or connectable to radio circuitry 122 for signal reception or transmittance and / or amplification. Node 100 may be adapted to carry out any of the methods for operating a radio node or network node disclosed herein; in particular, it may comprise corresponding circuitry, e.g. processing circuitry, and / or modules. The antenna circuitry 124 may be connected to and / or comprise an antenna array. The node 100, respectively 1405 its circuitry, may be adapted to perform any of the methods of operating a network node or a radio node as described herein; in particular, it may comprise corresponding circuitry, e.g. processing circuitry, and / or modules. The radio node 100 may generally comprise communication circuitry, e.g. for communication with another network node, like a radio node, and / or with a core network and / or an internet or local net, in particular with an 1410 information system, which may provide information and / or data to be transmitted to a user equipment. A DFE may be considered part of radio circuitry; an analog frontend may be associated to radio circuitry and / or antenna circuitry. Antenna circuitry 124 may comprise, and / or be connected or connectable, to an antenna array or antenna arrangement as described herein. 1415

[0228] In general, the wireless device and / or network node may operate in, and / or the communication signalling may be in TDD operation. It should be noted that the transmission of signalling from transmission sources may be synchronised and simultaneous; a shift in time may occur due to different propagation times, e.g. due to different beams and / or source locations. 1420

[0229] A wireless device may in general comprise processing circuitry and / or radio circuitry, in particular a receiver and / or transceiver and / or transmitter, for performing measurement and / or to control beam switch and / or control beam-forming and / or receive and / or transmit signalling like communication signalling and / or sensing signalling. The wireless device may in particular be implemented as terminal or a user equipment. However, in 1425

[0230] P111680W001 40 / 88 some cases, e.g. relay and / or back-link and / or IAB scenarios, it may be implemented as network node or network radio node. A network node may in general comprise processing circuitry and / or radio circuitry, in particular a receiver and / or transceiver and / or transmitter, for transmitting reference signalling and / or a beam switch indication and / or for beam switching and / or to control beam switch and / or control beam-forming and / or re- 1430 ceive and / or transmit signalling like communication signalling and / or sensing signalling..

[0231] The second radio node may in particular be implemented as a network node, e.g. a network radio node and / or base station or a relay node or IAB node. However, in some cases, e.g. sidelink scenarios, the second radio node may be implemented as a wireless device or terminal, e.g. a user equipment. 1435

[0232] In general, sensing signalling may be based on the same wave-form as the communication signalling. However, it may be based on a different wave-form in some variants. The sensing signalling may be OFDM based, for example, regular OFDM, or spread OFDM like DFT-s-OFDM, and / or pulse-shaped OFDM, or filter-bank based, or Single Carrier based. The communication signalling may be OFDM based, for example, regular OFDM, 1440 or spread OFDM like DFT-s-OFDM, and / or pulse-shaped OFDM, or filter-bank based, or Single Carrier based. The sensing signalling may be transmitted in a transmission timing structure corresponding to the transmission timing structure associated to the communication signalling, e.g. a frame structure, and / or be based on the same or a different numerology as the communication signalling. The timing structure (e.g., symbol 1445 duration or allocation unit duration) and / or types of modulation symbols carried by signalling may be based on the wave-form used.

[0233] In general, a block symbol may represent and / or correspond to an extension in time domain, e.g. a time interval. A block symbol duration (the length of the time interval) may correspond to the duration of an OFDM symbol or a corresponding duration, and / or 1450 may be based and / or defined by a subcarrier spacing used (e.g., based on the numerology) or equivalent, and / or may correspond to the duration of a modulation symbol (e.g., for OFDM or similar frequency domain multiplexed types of signalling). It may be considered that a block symbol comprises a plurality of modulation symbols, e.g. based on a subcarrier spacing and / or numerology or equivalent, in particular for time domain multiplexed 1455 types (on the symbol level for a single transmitter) of signalling like single-carrier based signalling, e.g. SC-FDE or SC-FDMA (in particular, FDF-SC-FDMA or pulse-shaped SC-FDMA). The number of symbols may be based on and / or defined by the number of subcarrier to be DFTS-spread (for SC-FDMA) and / or be based on a number of FFT samples, e.g. for spreading and / or mapping, and / or equivalent, and / or may be predefined 1460 and / or configured or configurable. A block symbol in this context may comprise and / or contain a plurality of individual modulation symbols, which may be for example 1000 or

[0234] P111680W001 41 / 88 more, or 3000 or more, or 3300 or more. The number of modulation symbols in a block symbol may be based and / or be dependent on a bandwidth scheduled for transmission of signalling in the block symbol. A block symbol and / or a number of block symbols 1465 (an integer smaller than 20, e.g. equal to or smaller than 14 or 7 or 4 or 2 or a flexible number) may be a unit (e.g., allocation unit) used for scheduling and / or allocation of resources, in particular in time domain. To a block symbol (e.g., scheduled or allocated) and / or block symbol group and / or allocation unit, there may be associated a frequency range and / or frequency domain allocation and / or bandwidth allocated for transmission. 1470

[0235] An allocation unit, and / or a block symbol, may be associated to a specific (e.g., physical) channel and / or specific type of signalling, for example reference signalling. In some cases, there may be a block symbol associated to a channel that also is associated to a form of reference signalling and / or pilot signalling and / or tracking signalling associated to the channel, for example for timing purposes and / or decoding purposes (such signalling may 1475 comprise a low number of modulation symbols and / or resource elements of a block symbol, e.g. less than 10% or less than 5% or less than 1% of the modulation symbols and / or resource elements in a block symbol). To a block symbol, there may be associated resource elements; a resource element may be represented in time / frequency domain, e.g. by the smallest frequency unit carrying or mapped to (e.g., a subcarrier) in frequency domain 1480 and the duration of a modulation symbol in time domain. A block symbol may comprise, and / or to a block symbol may be associated, a structure allowing and / or comprising a number of modulation symbols, and / or association to one or more channels (and / or the structure may dependent on the channel the block symbol is associated to and / or is allocated or used for), and / or reference signalling (e.g., as discussed above), and / or 1485 one or more guard periods and / or transient periods, and / or one or more affixes (e.g., a prefix and / or suffix and / or one or more infixes (entered inside the block symbol)), in particular a cyclic prefix and / or suffix and / or infix. A cyclic affix may represent a repetition of signalling and / or modulation symbol / s used in the block symbol, with possible slight amendments to the signalling structure of the affix to provide a smooth 1490 and / or continuous and / or differentiable connection between affix signalling and signalling of modulation symbols associated to the content of the block symbol (e.g., channel and / or reference signalling structure). In some cases, in particular some OFDM-based waveforms, an affix may be included into a modulation symbol. In other cases, e.g. some single carrier-based wave-forms, an affix may be represented by a sequence of modulation 1495 symbols within the block symbol. It may be considered that in some cases a block symbol is defined and / or used in the context of the associated structure.

[0236] Communicating may comprise transmitting or receiving. It may be considered that communicating like transmitting signalling is based on a SC-FDM based wave- form, and / or

[0237] P111680W001 42 / 88 corresponds to a Frequency Domain Filtered (FDF) DFTS-OFDM wave-form. However, 1500 the approaches may be applied to a Single Carrier based wave-form, e.g. a SC-FDM or SC-FDE- wave-form, which may be pulse-shaped / FDF-based. It should be noted that SC-FDM may be considered DFT-spread OFDM, such that SC-FDM and DFTS-OFDM may be used interchangeably. Alternatively, or additionally, the signalling (e.g., first signalling and / or second signalling) and / or beam / s (in particular, the first received beam and / or 1505 second received beam) may be based on a wave-form with CP or comparable guard time.

[0238] The received beam and the transmission beam of the first beam pair may have the same (or similar) or different angular and / or spatial extensions; the received beam and the transmission beam of the second beam pair may have the same (or similar) or different angular and / or spatial extensions. It may be considered that the received beam and / or 1510 transmission beam of the first and / or second beam pair have angular extension of 20 degrees or less, or 15 degrees or less, or 10 or 5 degrees or less, at least in one of horizontal or vertical direction, or both; different beams may have different angular extensions. An extended guard interval or switching protection interval may have a duration corresponding to essentially or at least N CP (cyclic prefix) durations or equivalent duration, wherein 1515 N may be 2, or 3 or 4. An equivalent to a CP duration may represent the CP duration associated to signalling with CP (e.g., SC-FDM-based or OFDM-based) for a wave-form without CP with the same or similar symbol time duration as the signalling with CP.

[0239] Pulse-shaping (and / or performing FDF for) a modulation symbol and / or signalling, e.g. associated to a first subcarrier or bandwidth, may comprise mapping the modulation 1520 symbol (and / or the sample associated to it after FFT) to an associated second subcarrier or part of the bandwidth, and / or applying a shaping operation regarding the power and / or amplitude and / or phase of the modulation symbol on the first subcarrier and the second subcarrier, wherein the shaping operation may be according to a shaping function.

[0240] Pulse-shaping signalling may comprise pulse-shaping one or more symbols; pulse-shaped 1525 signalling may in general comprise at least one pulse-shaped symbol. Pulse-shaping may be performed based on a Nyquist-filter. It may be considered that pulse-shaping is performed based on periodically extending a frequency distribution of modulation symbols (and / or associated samples after FFT) over a first number of subcarrier to a larger, second number of subcarriers, wherein a subset of the first number of subcarriers from one end of 1530 the frequency distribution is appended at the other end of the first number of subcarriers.

[0241] In some variants, communicating may be based on a numerology (which may, e.g., be represented by and / or correspond to and / or indicate a subcarrier spacing and / or symbol time length) and / or an SC-FDM based wave- form (including a FDF-DFTS-FDM based wave-form) or a single-carrier based wave-form. Whether to use pulse-shaping or FDF on 1535 a SC-FDM or SC-based wave-form may depend on the modulation scheme (e.g., MCS)

[0242] P111680W001 43 / 88 used. Such wave- forms may utilise a cyclic prefix and / or benefit particularly from the described approaches. Communicating may comprise and / or be based on beamforming, e.g. transmission beamforming and / or reception beamforming, respectively. It may be considered that a beam is produced by performing analog beamforming to provide the 1540 beam, e.g. a beam corresponding to a reference beam. Thus, signalling may be adapted, e.g. based on movement of the communication partner. A beam may for example be produced by performing analog beamforming to provide a beam corresponding to a reference beam. This allows efficient postprocessing of a digitally formed beam, without requiring changes to a digital beamforming chain and / or without requiring changes to a standard 1545 defining beam forming precoders. In general, a beam may be produced by hybrid beamforming, and / or by digital beamforming, e.g. based on a precoder. This facilitates easy processing of beams, and / or limits the number of power amplifiers / ADC / DAC required for antenna arrangements. It may be considered that a beam is produced by hybrid beamforming, e.g. by analog beamforming performed on a beam representation or beam 1550 formed based on digital beamforming. Monitoring and / or performing cell search may be based on reception beamforming, e.g. analog or digital or hybrid reception beamforming.

[0243] The numerology may determine the length of a symbol time interval and / or the duration of a cyclic prefix. The approaches described herein are particularly suitable to SC-FDM, to ensure orthogonality, in particular sub-carrier orthogonality, in corresponding systems, 1555 but may be used for other wave-forms. Communicating may comprise utilising a waveform with cyclic prefix. The cyclic prefix may be based on a numerology, and may help keeping signalling orthogonal. Communicating may comprise, and / or be based on performing cell search, e.g. for a wireless device or terminal, or may comprise transmitting cell identifying signalling and / or a selection indication, based on which a radio node re- 1560 ceiving the selection indication may select a signalling bandwidth from a set of signalling bandwidths for performing cell search.

[0244] A beam or beam pair may in general be targeted at one radio node, or a group of radio nodes and / or an area including one or more radio nodes. In many cases, a beam or beam pair may be receiver-specific (e.g., UE-specific), such that only one radio node is served 1565 per beam / beam pair. A beam pair switch or switch of received beam (e.g., by using a different reception beam) and / or transmission beam may be performed at a border of a transmission timing structure, e.g. a slot border, or within a slot, for example between symbols. Some tuning of radio circuitry, e.g. for receiving and / or transmitting, may be performed. Beam pair switching may comprise switching from a second received beam 1570 to a first received beam, and / or from a second transmission beam to a first transmission beam. Switching may comprise inserting a guard period to cover retuning time; however, circuitry may be adapted to switch sufficiently quickly to essentially be instantaneous;

[0245] P111680W001 44 / 88 this may in particular be the case when digital reception beamforming is used to switch reception beams for switching received beams. 1575

[0246] A reference beam (or reference signalling beam) may be a beam comprising reference signalling, based on which for example a of beam signalling characteristics may be determined, e.g. measured and / or estimated. A signalling beam may comprise signalling like control signalling and / or data signalling and / or reference signalling. A reference beam may be transmitted by a source or transmitting radio node, in which case one or more 1580 beam signalling characteristics may be reported to it from a receiver, e.g. a wireless device. However, in some cases it may be received by the radio node from another radio node or wireless device. In this case, one or more beam signalling characteristics may be determined by the radio node. A signalling beam may be a transmission beam, or a reception beam. A set of signalling characteristics may comprise a plurality of subsets 1585 of beam signalling characteristics, each subset pertaining to a different reference beam.

[0247] Thus, a reference beam may be associated to different beam signalling characteristics.

[0248] A beam signalling characteristic, respectively a set of such characteristics, may represent and / or indicate a signal strength and / or signal quality of a beam and / or a delay characteristic and / or be associated with received and / or measured signalling carried on a beam. 1590 Beam signalling characteristics and / or delay characteristics may in particular pertain to, and / or indicate, a number and / or list and / or order of beams with best (e.g., lowest mean delay and / or lowest spread / range) timing or delay spread, and / or of strongest and / or best quality beams, e.g. with associated delay spread. A beam signalling characteristic may be based on measurement / s performed on reference signalling carried on the refer- 1595 ence beam it pertains to. The measurement / s may be performed by the radio node, or another node or wireless device. The use of reference signalling allows improved accuracy and / or gauging of the measurements. In some cases, a beam and / or beam pair may be represented by a beam identity indication, e.g. a beam or beam pair number. Such an indication may be represented by one or more signalling sequences (e.g., a specific reference 1600 signalling sequences or sequences), which may be transmitted on the beam and / or beam pair, and / or a signalling characteristic and / or a resource / s used (e.g., time / frequency and / or code) and / or a specific RNTI (e.g., used for scrambling a CRC for some messages or transmissions) and / or by information provided in signalling, e.g. control signalling and / or system signalling, on the beam and / or beam pair, e.g. encoded and / or provided 1605 in an information held or as information element in some form of message of signalling, e.g. DCI and / or MAC and / or RRC signalling.

[0249] A reference beam may in general be one of a set of reference beams, the second set of reference beams being associated to the set of signalling beams. The sets being associated

[0250] P111680W001 45 / 88 may refer to at least one beam of the first set being associated and / or corresponding to the 1610 second set (or vice versa), e.g. being based on it, for example by having the same analog or digital beamforming parameters and / or precoder and / or the same shape before analog beamforming, and / or being a modified form thereof, e.g. by performing additional analog beamforming. The set of signalling beams may be referred to as a first set of beams, a set of corresponding reference beams may be referred to as second set of beams. 1615

[0251] In some variants, a reference beam and / or reference beams and / or reference signalling may correspond to and / or carry random access signalling, e.g. a random access preamble. Such a reference beam or signalling may be transmitted by another radio node. The signalling may indicate which beam is used for transmitting. Alternatively, the reference beams may be beams receiving the random access signalling. Random access signalling may be used 1620 for initial connection to the radio node and / or a cell provided by the radio node, and / or for reconnection. Utilising random access signalling facilitates quick and early beam selection.

[0252] The random access signalling may be on a random access channel, e.g. based on broadcast information provided by the radio node (the radio node performing the beam selection), e.g. with synchronisation signalling (e.g., SSB block and / or associated thereto). The 1625 reference signalling may correspond to synchronisation signalling, e.g. transmitted by the radio node in a plurality of beams. The characteristics may be reported on by a node receiving the synchronisation signalling, e.g. in a random access process, e.g. a msg3 for contention resolution, which may be transmitted on a physical uplink shared channel based on a resource allocation provided by the radio node. 1630

[0253] A delay characteristic (which may correspond to delay spread information) and / or a measurement report may represent and / or indicate at least one of mean delay, and / or delay spread, and / or delay distribution, and / or delay spread distribution, and / or delay spread range, and / or relative delay spread, and / or energy (or power) distribution, and / or impulse response to received signalling, and / or the power delay profile of the received 1635 signals, and / or power delay profile related parameters of the received signal. A mean delay may represent the mean value and / or an averaged value of the delay spread, which may be weighted or unweighted. A distribution may be distribution over time / delay, e.g. of received power and / or energy of a signal. A range may indicate an interval of the delay spread distribution over time / delay, which may cover a predetermined percentage of the 1640 delay spread respective received energy or power, e.g. 50% or more, 75% or more, 90% or more, or 100%. A relative delay spread may indicate a relation to a threshold delay, e.g. of the mean delay, and / or a shift relative to an expected and / or configured timing, e.g. a timing at which the signalling would have been expected based on the scheduling, and / or a relation to a cyclic prefix duration (which may be considered on form of a threshold). 1645 Energy distribution or power distribution may pertain to the energy or power received over

[0254] P111680W001 46 / 88 the time interval of the delay spread. A power delay profile may pertain to representations of the received signals, or the received signals energy / power, across time / delay. Power delay profile related parameters may pertain to metrics computed from the power delay profile. Different values and forms of delay spread information and / or report may be 1650 used, allowing a wide range of capabilities. The kind of information represented by a measurement report may be predefined, or be configured or configurable, e.g. with a measurement configuration and / or reference signalling configuration, in particular with higher layer signalling like RRC or MAC signalling and / or physical layer signalling like DCI signalling. 1655

[0255] In general, different beam pair may differ in at least one beam; for example, a beam pair using a first received beam and a first transmission beam may be considered to be different from a second beam pair using the first received beam and a second transmission beam. A transmission beam using no precoding and / or beamforming, for example using the natural antenna profile, may be considered as a special form of transmission beam of 1660 a transmission beam pair. A beam may be indicated to a radio node by a transmitter with a beam indication and / or a configuration, which for example may indicate beam parameters and / or time / frequency resources associated to the beam and / or a transmission mode and / or antenna profile and / or antenna port and / or precoder associated to the beam. Different beams may be provided with different content, for example different 1665 received beams may carry different signalling; however, there may be considered cases in which different beams carry the same signalling, for example the same data signalling and / or reference signalling. The beams may be transmitted by the same node and / or transmission point and / or antenna arrangement, or by different nodes and / or transmission points and / or antenna arrangements. 1670

[0256] Communicating utilising a beam pair or a beam may comprise receiving signalling on a received beam (which may be a beam of a beam pair), and / or transmitting signalling on a beam, e.g. a beam of a beam pair. The following terms are to be interpreted from the point of view of the referred radio node: a received beam may be a beam carrying signalling received by the radio node (for reception, the radio node may use a reception 1675 beam, e.g. directed to the received beam, or be non-beamformed). A transmission beam may be a beam used by the radio node to transmit signalling. A beam pair may consist of a received beam and a transmission beam. The transmission beam and the received beam of a beam pair may be associated to each and / or correspond to each other, e.g. such that signalling on the received beam and signalling on a transmission beam travel 1680 essentially the same path (but in opposite directions), e.g. at least in a stationary or almost stationary condition. It should be noted that the terms “first” and “second” do not necessarily denote an order in time; a second signalling may be received and / or

[0257] P111680W001 47 / 88 transmitted before, or in some cases simultaneous to, first signalling, or vice versa. The received beam and transmission beam of a beam pair may be on the same carrier or 1685 frequency range or bandwidth part, e.g. in a TDD operation; however, variants with FDD may be considered as well. Different beam pairs may operate on the same frequency ranges or carriers or bandwidth parts (e.g., such that transmission beams operate on the same frequency range or carriers or bandwidth part, and received beams on the same frequency range or carriers or bandwidth part (the transmission beam and received beams 1690 may be on the same or different ranges or carriers or BWPs). Communicating utilizing a first beam pair and / or first beam may be based on, and / or comprise, switching from the second beam pair or second beam to the first beam pair or first beam for communicating.

[0258] The switching may be controlled by the network, for example a network node (which may be the source or transmitter of the received beam of the first beam pair and / or second 1695 beam pair, or be associated thereto, for example associated transmission points or nodes in dual connectivity). Such controlling may comprise transmitting control signalling, e.g. physical layer signalling and / or higher layer signalling. In some cases, the switching may be performed by the radio node without additional control signalling, for example based on measurements on signal quality and / or signal strength of beam pairs (e.g., of first and 1700 second received beams), in particular the first beam pair and / or the second beam pair.

[0259] For example, it may be switched to the first beam pair (or first beam) if the signal quality or signal strength measured on the second beam pair (or second beam) is considered to be insufficient, and / or worse than corresponding measurements on the first beam pair indicate. Measurements performed on a beam pair (or beam) may in particular comprise 1705 measurements performed on a received beam of the beam pair. It may be considered that the timing indication may be determined before switching from the second beam pair to the first beam pair for communicating. Thus, the synchronisation may be in place and / or the timing indication may be available for synchronising) when starting communication utilizing the first beam pair or first beam. However, in some cases the timing indication 1710 may be determined after switching to the first beam pair or first beam. This may be in particular useful if first signalling is expected to be received after the switching only, for example based on a periodicity or scheduled timing of suitable reference signalling on the first beam pair, e.g. first received beam. In general, a reception beam of a node may be associated to and / or correspond to a transmission beam of the node, e.g. such 1715 that the (spatial) angle of reception of the reception beam and the (spatial) angle of transmission of the transmission beam at least partially, or essentially or fully, overlap and / or coincide, in particular for TDD operation and / or independent of frequency. Spatial correspondence between beams may be considered in some cases, e.g. such that a beam pair (e.g., transmission beam of a transmitting node and reception beam of a receiving 1720 node) may be considered to comprise corresponding beams (e.g., the reception beam is

[0260] P111680W001 48 / 88 suitable and / or the best beam to receive transmissions on the transmission beam, e.g. based on a threshold signal quality and / or signal strength and / or measurements); to each of such beams, there may be an associated or corresponding complementary beam of the respective node (e.g., to a transmission beam of a beam pair, there may be associated a 1725 reception beam of the transmitting node, and / or to the reception beam of a beam pair, there may be associated a transmitting beam of the receiving node; if the beams (e.g., at least essentially or substantially) overlap (e.g., in spatial angle), in some cases a beam pair may be considered to indicate four beams (or actually, two beam pairs).

[0261] In some cases, to one or more beams or signals or signallings may be associated a Quasi- 1730 CoLocation (QCL) characteristic or set of characteristics, or QCL class (also referred to as QCL type) or QCL identity; beams or signal or signallings sharing such may be considered to be Quasi-Colocated. Quasi-Colocated beams or signals or signallings may be considered (e.g., by a receiver) as the same beam or originating from the same transmitter or transmission source, at least in regard to the QCL characteristic or set or class or 1735 identity, and / or to share the characteristic / s. QCL characteristics may pertain to propagation of signalling, and / or one or more delay characteristics, and / or pathloss, and / or signal quality, and / or signal strength, and / or beam direction, and / or beam shape (in particular, angle or area, e.g. area of coverage), and / or Doppler shift, and / or Doppler spread, and / or delay spread, and / or time synchronisation, and / or frequency synchroni- 1740 sation, and / or one or more other parameters, e.g. pertaining to a propagation channel and / or spatial RX param eter / s (which may refer to reception beam and / or transmission beam, e.g. shape or coverage or direction). A QCL characteristic may pertain to a specific channel (e.g., physical layer channel like a control channel or data channel) and / or reference signalling type and / or antenna port. Different QCL classes or types may per- 1745 tain to different QCL characteristics or sets of characteristics; a QCL class may define and / or pertain to one or more criteria and / or thresholds and / or ranges for one or more QCL characteristics beams have to fulfill to be considered Quasi-Colocated according to this class; a QCL identity may refer to and / or represent all beams being quasi-colocated, according to a QCL class. Different classes may pertain to one or more of the same 1750 characteristics (e.g., different classes may have different criteria and / or thresholds and / or ranges for one or more characteristics) and / or to different characteristics. A QCL indication may be seen as a form of beam indication, e.g. pertaining to all beams belonging to one QCL class and / or QCL identity and / or quasi-colocated beams. A QCL identity may be indicated by a QCL indication. In some cases, a beam, and / or a beam indication, 1755 may be considered to refer and / or represent a to a QCL identity, and / or to represent quasi-colocated beams or signals or signallings.

[0262] Transmission on multiple layers (multi-layer transmission) may refer to transmission of

[0263] P111680W001 49 / 88 communication signalling and / or reference signalling simultaneously in one or more beams and / or using a plurality of transmission sources, e.g. controlled by one network node 1760 or one wireless device. The layers may refer to layers of transmission; a layer may be considered to represent one data or signalling stream. Different layers may carry different data and / or data streams, e.g., to increase data throughput. In some cases, the same data or data stream may be transported on different layers, e.g. to increase reliability.

[0264] Multi-layer transmission may provide diversity, e.g. transmission diversity and / or spatial 1765 diversity. It may be considered that multi-layer transmission comprises 2, or more than 2 layers; the number of layers of transmission may be represented by a rank or rank indication.

[0265] A transmission source may in particular comprise, and / or be represented by, and / or associated to, an antenna or group of antenna elements or antenna sub-array or antenna 1770 array or transmission point or TRP or TP (Transmission Point) or access point. In some cases, a transmission source may be represented or representable, and / or correspond to, and / or associated to, an antenna port or layer of transmission, e.g. for multi-layer transmission. Different transmission sources may in particular comprise different and / or separately controllable antenna element / s or (sub-)arrays and / or be associated to different 1775 antenna ports. In particular, analog beamforming may be used, with separate analog control of the different transmission sources. An antenna port may indicate a transmission source, and / or a one or more transmission parameter, in particular of reference signalling associated to the antenna port. In particular, transmission parameters pertaining to, and / or indicating a frequency domain distribution or mapping (e.g., which comb to use 1780 and / or which subcarrier or frequency offset to use, or similar) of modulation symbols of the reference signalling, and / or to which cyclic shift to use (e.g., to shift elements of a modulation symbol sequence, or a root sequence, or a sequence based on or derived from the root sequence) and / or to which cover code to use (e.g., (e.g., to shift elements of a modulation symbol sequence, or a root sequence, or a sequence based on or derived 1785 from the root sequence). In some cases, a transmission source may represent a target for reception, e.g. if it is implemented as a TRP or AP (Access Point).

[0266] In some variants, reference signalling may be and / or comprise CSI-RS and / or PT-RS and / or DMRS, e.g. transmitted by the network node. In other variants, the reference signalling may be transmitted by a UE, e.g. to a network node or other UE, in which 1790 case it may comprise and / or be Sounding Reference signalling. Other, e.g. new, forms of reference signalling may be considered and / or used. In general, a modulation symbol of reference signalling respectively a resource element carrying it may be associated to a cyclic prefix.

[0267] P111680W001 50 / 88 Data signalling may be on a data channel, for example on a PDSCH or PSSCH, or on a 1795 dedicated data channel, e.g. for low latency and / or high reliability, e.g. a URLLC channel.

[0268] Control signalling may be on a control channel, for example on a common control channel or a PDCCH or PSCCH, and / or comprise one or more DCI messages or SCI messages.

[0269] Reference signalling may be associated to control signalling and / or data signalling, e.g.

[0270] DM-RS and / or PT-RS. 1800

[0271] Reference signalling, for example, may comprise DM-RS and / or pilot signalling and / or discovery signalling and / or synchronisation signalling and / or sounding signalling and / or phase tracking signalling and / or cell-specific reference signalling and / or user-specific signalling, in particular CSI-RS. Reference signalling in general may be signalling with one or more signalling characteristics, in particular transmission power and / or sequence of 1805 modulation symbols and / or resource distribution and / or phase distribution known to the receiver. Thus, the receiver can use the reference signalling as a reference and / or for training and / or for compensation. The receiver can be informed about the reference signalling by the transmitter, e.g. being configured and / or signalling with control signalling, in particular physical layer signalling and / or higher layer signalling (e.g., DCI and / or RRC sig- 1810 nailing), and / or may determine the corresponding information itself, e.g. a network node configuring a UE to transmit reference signalling. Reference signalling may be signalling comprising one or more reference symbols and / or structures. Reference signalling may be adapted for gauging and / or estimating and / or representing transmission conditions, e.g. channel conditions and / or transmission path conditions and / or channel (or signal or 1815 transmission) quality. It may be considered that the transmission characteristics (e.g., signal strength and / or form and / or modulation and / or timing) of reference signalling are available for both transmitter and receiver of the signalling (e.g., due to being predefined and / or configured or configurable and / or being communicated). Different types of reference signalling may be considered, e.g. pertaining to uplink, downlink or sidelink, 1820 cell-specific (in particular, cell- wide, e.g., CRS) or device or user specific (addressed to a specific target or user equipment, e.g., CSI-RS), demodulation-related (e.g., DMRS) and / or signal strength related, e.g. power-related or energy-related or amplitude-related (e.g., SRS or pilot signalling) and / or phase-related, etc.

[0272] References to specific resource structures like an allocation unit and / or block symbol 1825 and / or block symbol group and / or transmission timing structure and / or symbol and / or slot and / or mini-slot and / or subcarrier and / or carrier may pertain to a specific numerology, which may be predefined and / or configured or configurable. A transmission timing structure may represent a time interval, which may cover one or more symbols. Some examples of a transmission timing structure are transmission time interval (TTI), sub- 1830 frame, slot and mini-slot. A slot may comprise a predetermined, e.g. predefined and / or

[0273] P111680W001 51 / 88 configured or configurable, number of symbols, e.g. 6 or 7, or 12 or 14. A mini-slot may comprise a number of symbols (which may in particular be configurable or configured) smaller than the number of symbols of a slot, in particular 1, 2, 3 or 4, or more symbols, e.g. less symbols than symbols in a slot. A transmission timing structure may cover a 1835 time interval of a specific length, which may be dependent on symbol time length and / or cyclic prefix used. A transmission timing structure may pertain to, and / or cover, a specific time interval in a time stream, e.g. synchronized for communication. Timing structures used and / or scheduled for transmission, e.g. slot and / or mini-slots, may be scheduled in relation to, and / or synchronized to, a timing structure provided and / or defined by other 1840 transmission timing structures. Such transmission timing structures may define a timing grid, e.g., with symbol time intervals within individual structures representing the smallest timing units. Such a timing grid may for example be defined by slots or subframes (wherein in some cases, subframes may be considered specific variants of slots). A transmission timing structure may have a duration (length in time) determined based on the 1845 durations of its symbols, possibly in addition to cyclic prefix / es used. The symbols of a transmission timing structure may have the same duration, or may in some variants have different duration. The number of symbols in a transmission timing structure may be predefined and / or configured or configurable, and / or be dependent on numerology. The timing of a mini-slot may generally be configured or configurable, in particular by the 1850 network and / or a network node. The timing may be configurable to start and / or end at any symbol of the transmission timing structure, in particular one or more slots.

[0274] A transmission quality parameter may in general correspond to the number R of retransmissions and / or number T of total transmissions, and / or coding (e.g., number of coding bits, e.g. for error detection coding and / or error correction coding like FEC coding) 1855 and / or code rate and / or BLER and / or BER requirements and / or transmission power level (e.g., minimum level and / or target level and / or base power level P0 and / or transmission power control command, TPC, step size) and / or signal quality, e.g. SNR and / or SIR and / or SINR and / or power density and / or energy density.

[0275] A buffer state report (or buffer status report, BSR) may comprise information represent- 1860 ing the presence and / or size of data to be transmitted (e.g., available in one or more buffers, for example provided by higher layers). The size may be indicated explicitly, and / or indexed to range / s of sizes, and / or may pertain to one or more different channel / s and / or acknowledgement processes and / or higher layers and / or channel groups / s, e.g, one or more logical channel / s and / or transport channel / s and / or groups thereof: The 1865 structure of a BSR may be predefined and / or configurable of configured, e.g. to override and / or amend a predefined structure, for example with higher layer signalling, e.g. RRC signalling. There may be different forms of BSR with different levels of resolution and / or

[0276] P111680W001 52 / 88 information, e.g. a more detailed long BSR and a less detailed short BSR. A short BSR may concatenate and / or combine information of a long BSR, e.g. providing sums for data 1870 available for one or more channels and / or or channels groups and / or buffers, which might be represented individually in a long BSR; and / or may index a less-detailed range scheme for data available or buffered. A BSR may be used in lieu of a scheduling request, e.g. by a network node scheduling or allocating (uplink) resources for the transmitting radio node like a wireless device or UE or IAB node. 1875

[0277] There is generally considered a program product comprising instructions adapted for causing processing and / or control circuitry to carry out and / or control any method described herein, in particular when executed on the processing and / or control circuitry. Also, there is considered a carrier medium arrangement carrying and / or storing a program product as described herein. 1880

[0278] A carrier medium arrangement may comprise one or more carrier media. Generally, a carrier medium may be accessible and / or readable and / or receivable by processing or control circuitry. Storing data and / or a program product and / or code may be seen as part of carrying data and / or a program product and / or code. A carrier medium generally may comprise a guiding / transporting medium and / or a storage medium. A 1885 guiding / transporting medium may be adapted to carry and / or carry and / or store signals, in particular electromagnetic signals and / or electrical signals and / or magnetic signals and / or optical signals. A carrier medium, in particular a guiding / transporting medium, may be adapted to guide such signals to carry them. A carrier medium, in particular a guiding / transporting medium, may comprise the electromagnetic field, e.g. radio waves 1890 or microwaves, and / or optically transmissive material, e.g. glass fiber, and / or cable. A storage medium may comprise at least one of a memory, which may be volatile or nonvolatile, a buffer, a cache, an optical disc, magnetic memory, Flash memory, etc.

[0279] A system comprising one or more radio nodes as described herein, in particular a network node and a user equipment, is described. The system may be a wireless communication 1895 system, and / or provide and / or represent a radio access network.

[0280] Moreover, there may be generally considered a method of operating an information system, the method comprising providing information. Alternatively, or additionally, an information system adapted for providing information may be considered. Providing information may comprise providing information for, and / or to, a target system, which 1900 may comprise and / or be implemented as radio access network and / or a radio node, in particular a network node or user equipment or terminal. Providing information may comprise transferring and / or streaming and / or sending and / or passing on the information, and / or offering the information for such and / or for download, and / or triggering such

[0281] P111680W001 53 / 88 providing, e.g. by triggering a different system or node to stream and / or transfer and / or 1905 send and / or pass on the information. The information system may comprise, and / or be connected or connectable to, a target, for example via one or more intermediate systems, e.g. a core network and / or internet and / or private or local network. Information may be provided utilising and / or via such intermediate system / s. Providing information may be for radio transmission and / or for transmission via an air interface and / or utilising a RAN 1910 or radio node as described herein. Connecting the information system to a target, and / or providing information, may be based on a target indication, and / or adaptive to a target indication. A target indication may indicate the target, and / or one or more parameters of transmission pertaining to the target and / or the paths or connections over which the information is provided to the target. Such parameter / s may in particular pertain to the air 1915 interface and / or radio access network and / or radio node and / or network node. Example parameters may indicate for example type and / or nature of the target, and / or transmission capacity (e.g., data rate) and / or latency and / or reliability and / or cost, respectively one or more estimates thereof. The target indication may be provided by the target, or determined by the information system, e.g. based on information received from the target 1920 and / or historical information, and / or be provided by a user, for example a user operating the target or a device in communication with the target, e.g. via the RAN and / or air interface. For example, a user may indicate on a user equipment communicating with the information system that information is to be provided via a RAN, e.g. by selecting from a selection provided by the information system, for example on a user application 1925 or user interface, which may be a web interface. An information system may comprise one or more information nodes. An information node may generally comprise processing circuitry and / or communication circuitry. In particular, an information system and / or an information node may be implemented as a computer and / or a computer arrangement, e.g. a host computer or host computer arrangement and / or server or server arrangement. 1930 In some variants, an interaction server (e.g., web server) of the information system may provide a user interface, and based on user input may trigger transmitting and / or streaming information provision to the user (and / or the target) from another server, which may be connected or connectable to the interaction server and / or be part of the information system or be connected or connectable thereto. The information may be any kind of data, 1935 in particular data intended for a user of for use at a terminal, e.g. video data and / or audio data and / or location data and / or interactive data and / or game-related data and / or environmental data and / or technical data and / or traffic data and / or vehicular data and / or circumstantial data and / or operational data. The information provided by the information system may be mapped to, and / or mappable to, and / or be intended for mapping to, 1940 communication or data signalling and / or one or more data channels as described herein (which may be signalling or channel / s of an air interface and / or used within a RAN

[0282] P111680W001 54 / 88 and / or for radio transmission). It may be considered that the information is formatted based on the target indication and / or target, e.g. regarding data amount and / or data rate and / or data structure and / or timing, which in particular may be pertaining to a 1945 mapping to communication or data signalling and / or a data channel. Mapping information to data signalling and / or data channel / s may be considered to refer to using the signalling / channel / s to carry the data, e.g. on higher layers of communication, with the signalling / channel / s underlying the transmission. A target indication generally may comprise different components, which may have different sources, and / or which may indicate 1950 different characteristics of the target and / or communication path / s thereto. A format of information may be specifically selected, e.g. from a set of different formats, for information to be transmitted on an air interface and / or by a RAN as described herein. This may be particularly pertinent since an air interface may be limited in terms of capacity and / or of predictability, and / or potentially be cost sensitive. The format may be selected to be 1955 adapted to the transmission indication, which may in particular indicate that a RAN or radio node as described herein is in the path (which may be the indicated and / or planned and / or expected path) of information between the target and the information system. A (communication) path of information may represent the interface / s (e.g., air and / or cable interfaces) and / or the intermediate system / s (if any), between the information system 1960 and / or the node providing or transferring the information, and the target, over which the information is, or is to be, passed on. A path may be (at least partly) undetermined when a target indication is provided, and / or the information is provided / transferred by the information system, e.g. if an internet is involved, which may comprise multiple, dynamically chosen paths. Information and / or a format used for information may be 1965 packet-based, and / or be mapped, and / or be mappable and / or be intended for mapping, to packets. Alternatively, or additionally, there may be considered a method for operating a target device comprising providing a target indicating to an information system.

[0283] More alternatively, or additionally, a target device may be considered, the target device being adapted for providing a target indication to an information system. In another ap- 1970 proach, there may be considered a target indication tool adapted for, and / or comprising an indication module for, providing a target indication to an information system. The target device may generally be a target as described above. A target indication tool may comprise, and / or be implemented as, software and / or application or app, and / or web interface or user interface, and / or may comprise one or more modules for implementing 1975 actions performed and / or controlled by the tool. The tool and / or target device may be adapted for, and / or the method may comprise, receiving a user input, based on which a target indicating may be determined and / or provided. Alternatively, or additionally, the tool and / or target device may be adapted for, and / or the method may comprise, receiving information and / or communication signalling carrying information, and / or operating on, 1980

[0284] P111680W001 55 / 88 and / or presenting (e.g., on a screen and / or as audio or as other form of indication), information. The information may be based on received information and / or communication signalling carrying information. Presenting information may comprise processing received information, e.g. decoding and / or transforming, in particular between different formats, and / or for hardware used for presenting. Operating on information may be independent of 1985 or without presenting, and / or proceed or succeed presenting, and / or may be without user interaction or even user reception, for example for automatic processes, or target devices without (e.g., regular) user interaction like MTC devices, of for automotive or transport or industrial use. The information or communication signalling may be expected and / or received based on the target indication. Presenting and / or operating on information may 1990 generally comprise one or more processing steps, in particular decoding and / or executing and / or interpreting and / or transforming information. Operating on information may generally comprise relaying and / or transmitting the information, e.g. on an air interface, which may include mapping the information onto signalling (such mapping may generally pertain to one or more layers, e.g. one or more layers of an air interface, e.g. RLC (Radio 1995 Link Control) layer and / or MAC layer and / or physical layer / s). The information may be imprinted (or mapped) on communication signalling based on the target indication, which may make it particularly suitable for use in a RAN (e.g., for a target device like a network node or in particular a UE or terminal). The tool may generally be adapted for use on a target device, like a UE or terminal. Generally, the tool may provide multiple function- 2000 alities, e.g. for providing and / or selecting the target indication, and / or presenting, e.g. video and / or audio, and / or operating on and / or storing received information. Providing a target indication may comprise transmitting or transferring the indication as signalling, and / or carried on signalling, in a RAN, for example if the target device is a UE, or the tool for a UE. It should be noted that such provided information may be transferred to 2005 the information system via one or more additionally communication interfaces and / or paths and / or connections. The target indication may be a higher-layer indication and / or the information provided by the information system may be higher-layer information, e.g. application layer or user-layer, in particular above radio layers like transport layer and physical layer. The target indication may be mapped on physical layer radio signalling, 2010 e.g. related to or on the user-plane, and / or the information may be mapped on physical layer radio communication signalling, e.g. related to or on the user-plane (in particular, in reverse communication directions). The described approaches allow a target indication to be provided, facilitating information to be provided in a specific format particularly suitable and / or adapted to efficiently use an air interface. A user input may for example 2015 represent a selection from a plurality of possible transmission modes or formats, and / or paths, e.g. in terms of data rate and / or packaging and / or size of information to be provided by the information system.

[0285] P111680W001 56 / 88 In general, a numerology and / or subcarrier spacing may indicate the bandwidth (in frequency domain) of a subcarrier of a carrier, and / or the number of subcarriers in a carrier 2020 and / or the numbering of the subcarriers in a carrier, and / or the symbol time length.

[0286] Different numerologies may in particular be different in the bandwidth of a subcarrier.

[0287] In some variants, all the subcarriers in a carrier have the same bandwidth associated to them. The numerology and / or subcarrier spacing may be different between carriers in particular regarding the subcarrier bandwidth. A symbol time length, and / or a time 2025 length of a timing structure pertaining to a carrier may be dependent on the carrier frequency, and / or the subcarrier spacing and / or the numerology. In particular, different numerologies may have different symbol time lengths, even on the same carrier.

[0288] Signalling may generally comprise one or more (e.g., modulation) symbols and / or signals and / or messages. A signal may comprise or represent one or more bits. An indication may 2030 represent signalling, and / or be implemented as a signal, or as a plurality of signals. One or more signals may be included in and / or represented by a message, signalling, in particular control signalling, may comprise a plurality of signals and / or messages, which may be transmitted on different carriers and / or be associated to different signalling processes, e.g. representing and / or pertaining to one or more such processes and / or corresponding 2035 information. An indication may comprise signalling, and / or a plurality of signals and / or messages and / or may be comprised therein, which may be transmitted on different carriers and / or be associated to different acknowledgement signalling processes, e.g. representing and / or pertaining to one or more such processes. Signalling associated to a channel may be transmitted such that represents signalling and / or information for that channel, 2040 and / or that the signalling is interpreted by the transmitter and / or receiver to belong to that channel. Such signalling may generally comply with transmission parameters and / or format / s for the channel.

[0289] An antenna arrangement may comprise one or more antenna elements (radiating elements), which may be combined in antenna arrays. An antenna array or sub-array may 2045 comprise one antenna element, or a plurality of antenna elements, which may be arranged e.g. two dimensionally (for example, a panel) or three dimensionally. It may be considered that each antenna array or sub-array or element is separately controllable, respectively that different antenna arrays are controllable separately from each other. A single antenna element / radiator may be considered the smallest example of a sub-array. Examples 2050 of antenna arrays comprise one or more multi-antenna panels or one or more individually controllable antenna elements. An antenna arrangement may comprise a plurality of antenna arrays. It may be considered that an antenna arrangement is associated to a (specific and / or single) radio node, e.g. a configuring or informing or scheduling radio node, e.g. to be controlled or controllable by the radio node. An antenna arrangement 2055

[0290] P111680W001 57 / 88 associated to a UE or terminal may be smaller (e.g., in size and / or number of antenna elements or arrays) than the antenna arrangement associated to a network node. Antenna elements of an antenna arrangement may be configurable for different arrays, e.g. to change the beamforming characteristics. In particular, antenna arrays may be formed by combining one or more independently or separately controllable antenna elements or 2060 sub-arrays. The beams may be provided by analog beamforming, or in some variants by digital beamforming, or by hybrid beamforming combing analog and digital beamforming.

[0291] The informing radio nodes may be configured with the manner of beam transmission, e.g. by transmitting a corresponding indicator or indication, for example as beam identify indication. However, there may be considered cases in which the informing radio node / s are 2065 not configured with such information, and / or operate transparently, not knowing the way of beamforming used. An antenna arrangement may be considered separately controllable in regard to the phase and / or amplitude / power and / or gain of a signal feed to it for transmission, and / or separately controllable antenna arrangements may comprise an independent or separate transmit and / or receive unit and / or ADC (analog-Digital-Converter, 2070 alternatively an ADC chain) or DCA (Digital-to-analog Converter, alternatively a DCA chain) to convert digital control information into an analog antenna feed for the whole antenna arrangement (the ADC / DCA may be considered part of, and / or connected or connectable to, antenna circuitry) or vice versa. A scenario in which an ADC or DCA is controlled directly for beamforming may be considered an analog beamforming scenario; 2075 such controlling may be performed after encoding / decoding and / or after modulation symbols have been mapped to resource elements. This may be on the level of antenna arrangements using the same ADC / DCA, e.g. one antenna element or a group of antenna elements associated to the same ADC / DCA. Digital beamforming may correspond to a scenario in which processing for beamforming is provided before feeding signalling to the 2080 ADC / DCA, e.g. by using one or more precoder / s and / or by precoding information, for example before and / or when mapping modulation symbols to resource elements. Such a precoder for beamforming may provide weights, e.g. for amplitude and / or phase, and / or may be based on a (precoder) codebook, e.g. selected from a codebook. A precoder may pertain to one beam or more beams, e.g. defining the beam or beams. The codebook 2085 may be configured or configurable, and / or be predefined. DFT beamforming may be considered a form of digital beamforming, wherein a DFT procedure is used to form one or more beams. Hybrid forms of beamforming may be considered.

[0292] A beam may be defined by a spatial and / or angular and / or spatial angular distribution of radiation and / or a spatial angle (also referred to as solid angle) or spatial (solid) angle 2090 distribution into which radiation is transmitted (for transmission beamforming) or from which it is received (for reception beamforming). Reception beamforming may comprise

[0293] P111680W001 58 / 88 only accepting signals coming in from a reception beam (e.g., using analog beamforming to not receive outside reception beam / s), and / or sorting out signals that do not come in in a reception beam, e.g. in digital postprocessing, e.g. digital beamforming. A 2095 beam may have a solid angle equal to or smaller than 4*pi sr (4*pi correspond to a beam covering all directions), in particular smaller than 2* pi, or pi, or pi / 2, or pi / 4 or pi / 8 or pi / 16. In particular for high frequencies, smaller beams may be used. Different beams may have different directions and / or sizes (e.g., solid angle and / or reach). A beam may have a main direction, which may be defined by a main lobe (e.g., center of the 2100 main lobe, e.g. pertaining to signal strength and / or solid angle, which may be averaged and / or weighted to determine the direction), and may have one or more sidelobes. A lobe may generally be defined to have a continuous or contiguous distribution of energy and / or power transmitted and / or received, e.g. bounded by one or more contiguous or contiguous regions of zero energy (or practically zero energy). A main lobe may comprise the lobe 2105 with the largest signal strength and / or energy and / or power content. However, sidelobes usually appear due to limitations of beamforming, some of which may carry signals with significant strength, and may cause multi-path effects. A sidelobe may generally have a different direction than a main lobe and / or other side lobes, however, due to reflections a sidelobe still may contribute to transmitted and / or received energy or power. A beam 2110 may be swept and / or switched over time, e.g., such that its (main) direction is changed, but its shape (angular / solid angle distribution) around the main direction is not changed, e.g. from the transmitter’s views for a transmission beam, or the receiver’s view for a reception beam, respectively. Sweeping may correspond to continuous or near continuous change of main direction (e.g., such that after each change, the main lobe from before the 2115 change covers at least partly the main lobe after the change, e.g. at least to 50 or 75 or 90 percent). Switching may correspond to switching direction non-continuously, e.g. such that after each change, the main lobe from before the change does not cover the main lobe after the change, e.g. at most to 50 or 25 or 10 percent.

[0294] Signal strength may be a representation of signal power and / or signal energy, e.g. as 2120 seen from a transmitting node or a receiving node. A beam with larger strength at transmission (e.g., according to the beamforming used) than another beam does may not necessarily have larger strength at the receiver, and vice versa, for example due to interference and / or obstruction and / or dispersion and / or absorption and / or reflection and / or attrition or other effects influencing a beam or the signalling it carries. Signal 2125 quality may in general be a representation of how well a signal may be received over noise and / or interference. A beam with better signal quality than another beam does not necessarily have a larger beam strength than the other beam. Signal quality may be represented for example by SIR, SNR, SINR, BER, BLER, Energy per resource element

[0295] P111680W001 59 / 88 over noise / interference or another corresponding quality measure. Signal quality and / or 2130 signal strength may pertain to, and / or may be measured with respect to, a beam, and / or specific signalling carried by the beam, e.g. reference signalling and / or a specific channel, e.g. a data channel or control channel. Signal strength may be represented by received signal strength, and / or relative signal strength, e.g. in comparison to a reference signal (strength). 2135

[0296] Uplink or sidelink signalling may be OFDMA (Orthogonal Frequency Division Multiple Access) or SC-FDMA (Single Carrier Frequency Division Multiple Access) signalling.

[0297] Downlink signalling may in particular be OFDMA signalling. However, signalling like communication signalling and / or sensing signalling is not limited thereto (Filter-Bank based signalling and / or Single- Carrier based signalling, e.g. SC-FDE signalling, may be 2140 considered alternatives).

[0298] A radio node may generally be considered a device or node adapted for wireless and / or radio (and / or millimeter wave) frequency communication, and / or for communication utilising an air interface, e.g. according to a communication standard.

[0299] A radio node may be a network node, or a user equipment or terminal. A network node 2145 may be any radio node of a wireless communication network, e.g. a base station and / or gNodeB (gNB) and / or eNodeB (eNB) and / or relay node and / or micro / nano / pico / femto node and / or transmission point (TP) and / or access point (AP) and / or other node, in particular for a RAN or other wireless communication network as described herein.

[0300] The terms user equipment (UE) and terminal may be considered to be interchangeable 2150 in the context of this disclosure. A wireless device, user equipment or terminal may represent an end device for communication utilising the wireless communication network, and / or be implemented as a user equipment according to a standard. Examples of user equipments may comprise a phone like a smartphone, a personal communication device, a mobile phone or terminal, a computer, in particular laptop, a sensor or machine with radio 2155 capability (and / or adapted for the air interface), in particular for MTC (Machine-Type-Communication, sometimes also referred to M2M, Machine- To-Machine), or a vehicle adapted for wireless communication. A user equipment or terminal may be mobile or stationary. A wireless device generally may comprise, and / or be implemented as, processing circuitry and / or radio circuitry, which may comprise one or more chips or sets of chips. 2160 The circuitry and / or circuitries may be packaged, e.g. in a chip housing, and / or may have one or more physical interfaces to interact with other circuitry and / or for power supply.

[0301] Such a wireless device may be intended for use in a user equipment or terminal.

[0302] A radio node may generally comprise processing circuitry and / or radio circuitry. A radio

[0303] P111680W001 60 / 88 node, in particular a network node, may in some cases comprise cable circuitry and / or 2165 communication circuitry, with which it may be connected or connectable to another radio node and / or a core network.

[0304] Circuitry may comprise integrated circuitry. Processing circuitry may comprise one or more processors and / or controllers (e.g., microcontrollers), and / or ASICs (Application Specific Integrated Circuitry) and / or FPGAs (Field Programmable Gate Array), or sim- 2170 ilar. It may be considered that processing circuitry comprises, and / or is (operatively) connected or connectable to one or more memories or memory arrangements. A memory arrangement may comprise one or more memories. A memory may be adapted to store digital information. Examples for memories comprise volatile and non-volatile memory, and / or Random Access Memory (RAM), and / or Read-Only-Memory (ROM), 2175 and / or magnetic and / or optical memory, and / or flash memory, and / or hard disk memory, and / or EPROM or EEPROM (Erasable Programmable ROM or Electrically Erasable Programmable ROM).

[0305] Radio circuitry may comprise one or more transmitters and / or receivers and / or transceivers (a transceiver may operate or be operable as transmitter and receiver, and / or may com- 2180 prise joint or separated circuitry for receiving and transmitting, e.g. in one package or housing), and / or may comprise one or more amplifiers and / or oscillators and / or filters, and / or may comprise, and / or be connected or connectable to antenna circuitry and / or one or more antennas and / or antenna arrays. An antenna array may comprise one or more antennas, which may be arranged in a dimensional array, e.g. 2D or 3D array, 2185 and / or antenna panels. A remote radio head (RRH) may be considered as an example of an antenna array. However, in some variants, an RRH may be also be implemented as a network node, depending on the kind of circuitry and / or functionality implemented therein.

[0306] Communication circuitry may comprise radio circuitry and / or cable circuitry. Commu- 2190 nication circuitry generally may comprise one or more interfaces, which may be air inter-face / s and / or cable interface / s and / or optical interface / s, e.g. laser-based. Interface / s may be in particular packet-based. Cable circuitry and / or a cable interfaces may comprise, and / or be connected or connectable to, one or more cables (e.g., optical fiber-based and / or wire-based), which may be directly or indirectly (e.g., via one or more intermedi- 2195 ate systems and / or interfaces) be connected or connectable to a target, e.g. controlled by communication circuitry and / or processing circuitry.

[0307] Any one or all of the modules disclosed herein may be implemented in software and / or firmware and / or hardware. Different modules may be associated to different components of a radio node, e.g. different circuitries or different parts of a circuitry. It may be consid- 2200

[0308] P111680W001 61 / 88 ered that a module is distributed over different components and / or circuitries. A program product as described herein may comprise the modules related to a device on which the program product is intended (e.g., a user equipment or network node) to be executed (the execution may be performed on, and / or controlled by the associated circuitry).

[0309] A wireless communication network may be or comprise a radio access network and / or 2205 a backhaul network (e.g. a relay or backhaul network or an IAB network), and / or a Radio Access Network (RAN) in particular according to a communication standard. A communication standard may in particular a standard according to 3GPP and / or 5G, e.g. according to NR or LTE, in particular LTE Evolution.

[0310] A wireless communication network may be and / or comprise a Radio Access Network 2210 (RAN), which may be and / or comprise any kind of cellular and / or wireless radio network, which may be connected or connectable to a core network. The approaches described herein are particularly suitable for a 5G network, e.g. LTE Evolution and / or NR (New Radio), respectively successors thereof. A RAN may comprise one or more network nodes, and / or one or more terminals, and / or one or more radio nodes. A network 2215 node may in particular be a radio node adapted for radio and / or wireless and / or cellular communication with one or more terminals. A terminal may be any device adapted for radio and / or wireless and / or cellular communication with or within a RAN, e.g. a user equipment (UE) or mobile phone or smartphone or computing device or vehicular communication device or device for machine- type-communication (MTC), etc. A terminal 2220 may be mobile, or in some cases stationary. A RAN or a wireless communication network may comprise at least one network node and a UE, or at least two radio nodes. There may be generally considered a wireless communication network or system, e.g. a RAN or RAN system, comprising at least one radio node, and / or at least one network node and at least one terminal. 2225

[0311] Transmitting in downlink may pertain to transmission from the network or network node to the terminal. Transmitting in uplink may pertain to transmission from the terminal to the network or network node. Transmitting in sidelink may pertain to (direct) transmission from one terminal to another. Uplink, downlink and sidelink (e.g., sidelink transmission and reception) may be considered communication directions. In some vari- 2230 ants, uplink and downlink may also be used to described wireless communication between network nodes, e.g. for wireless backhaul and / or relay communication and / or (wireless) network communication for example between base stations or similar network nodes, in particular communication terminating at such. It may be considered that backhaul and / or relay communication and / or network communication is implemented as a form of sidelink 2235 or uplink communication or similar thereto.

[0312] P111680W001 62 / 88 Control information or a control information message or corresponding signalling (control signalling) may be transmitted on a control channel, e.g. a physical control channel, which may be a downlink channel or (or a sidelink channel in some cases, e.g. one UE scheduling another UE). For example, control information / allocation information may be 2240 signaled by a network node on PDCCH (Physical Downlink Control Channel) and / or a PDSCH (Physical Downlink Shared Channel) and / or a HARQ-specihc channel. Acknowledgement signalling, e.g. as a form of control information or signalling like uplink control information / signalling, may be transmitted by a terminal on a PUCCH (Physical Uplink Control Channel) and / or PUSCH (Physical Uplink Shared Channel) and / or a 2245 HARQ-specihc channel. Multiple channels may apply for multi-component / multi-carrier indication or signalling.

[0313] Transmitting acknowledgement signalling may in general be based on and / or in response to subject transmission, and / or to control signalling scheduling subject transmission.

[0314] Such control signalling and / or subject signalling may be transmitted by a signalling ra- 2250 dio node (which may be a network node, and / or a node associated to it, e.g. in a dual connectivity scenario. Subject transmission and / or subject signalling may be transmission or signalling to which ACK / NACK or acknowledgement information pertains, e.g. indicating correct or incorrect reception and / or decoding of the subject transmission or signalling. Subject signalling or transmission may in particular comprise and / or be repre- 2255 sented by data signalling, e.g. on a PDSCH or PSSCH, or some forms of control signalling, e.g. on a PDCCH or PSSCH, for example for specific formats.

[0315] A signalling characteristic may be based on a type or format of a scheduling grant and / or scheduling assignment, and / or type of allocation, and / or timing of acknowledgement signalling and / or the scheduling grant and / or scheduling assignment, and / or resources 2260 associated to acknowledgement signalling and / or the scheduling grant and / or scheduling assignment. For example, if a specific format for a scheduling grant (scheduling or allocating the allocated resources) or scheduling assignment (scheduling the subject transmission for acknowledgement signalling) is used or detected, the first or second communication resource may be used. Type of allocation may pertain to dynamic allocation 2265 (e.g., using DCI / PDCCH) or semi-static allocation (e.g., for a configured grant). Timing of acknowledgement signalling may pertain to a slot and / or symbol / s the signalling is to be transmitted. Resources used for acknowledgement signalling may pertain to the allocated resources. Timing and / or resources associated to a scheduling grant or assignment may represent a search space or CORESET (a set of resources configured for reception of 2270 PDCCH transmissions) in which the grant or assignment is received. Thus, which transmission resource to be used may be based on implicit conditions, requiring low signalling overhead.

[0316] P111680W001 63 / 88 Scheduling may comprise indicating, e.g. with control signalling like DCI or SCI signalling and / or signalling on a control channel like PDCCH or PSCCH, one or more scheduling 2275 opportunities of a configuration intended to carry data signalling or subject signalling.

[0317] The configuration may be represented or representable by, and / or correspond to, a table.

[0318] A scheduling assignment may for example point to an opportunity of the reception allocation configuration, e.g. indexing a table of scheduling opportunities. In some cases, a reception allocation configuration may comprise 15 or 16 scheduling opportunities. The 2280 configuration may in particular represent allocation in time. It may be considered that the reception allocation configuration pertains to data signalling, in particular on a physical data channel like PDSCH or PSSCH. In general, the reception allocation configuration may pertain to downlink signalling, or in some scenarios to sidelink signalling. Control signalling scheduling subject transmission like data signalling may point and / or index 2285 and / or refer to and / or indicate a scheduling opportunity of the reception allocation configuration. It may be considered that the reception allocation configuration is configured or configurable with higher-layer signalling, e.g. RRC or MAC layer signalling. The reception allocation configuration may be applied and / or applicable and / or valid for a plurality of transmission timing intervals, e.g. such that for each interval, one or more opportu- 2290 nities may be indicated or allocated for data signalling. These approaches allow efficient and flexible scheduling, which may be semi-static, but may updated or reconfigured on useful timescales in response to changes of operation conditions.

[0319] Control information, e.g., in a control information message, in this context may in particular be implemented as and / or represented by a scheduling assignment, which may 2295 indicate subject transmission for feedback (transmission of acknowledgement signalling), and / or reporting timing and / or frequency resources and / or code resources. Reporting timing may indicate a timing for scheduled acknowledgement signalling, e.g. slot and / or symbol and / or resource set. Control information may be carried by control signalling.

[0320] Subject transmissions may comprise one or more individual transmissions. Scheduling as- 2300 signments may comprise one or more scheduling assignments. It should generally be noted that in a distributed system, subject transmissions, configuration and / or scheduling may be provided by different nodes or devices or transmission points. Different subject transmissions may be on the same carrier or different carriers (e.g., in a carrier aggregation), and / or same or different bandwidth parts, and / or on the same or different layers or beams, 2305 e.g. in a MIMO scenario, and / or to same or different ports. Generally, subject transmissions may pertain to different HARQ or ARQ processes (or different sub-processes, e.g. in MIMO with different beams / layers associated to the same process identifier, but different sub-process-identifiers like swap bits). A scheduling assignment and / or a HARQ codebook may indicate a target HARQ structure. A target HARQ structure may for example 2310

[0321] P111680W001 64 / 88 indicate an intended HARQ response to a subject transmission, e.g. the number of bits and / or whether to provide code block group level response or not. However, it should be noted that the actual structure used may differ from the target structure, e.g. due to the total size of target structures for a subpattern being larger than the predetermined size.

[0322] Transmitting acknowledgement signalling, also referred to as transmitting acknowledge- 2315 ment information or feedback information or simply as ARQ or HARQ feedback or feedback or reporting feedback, may comprise, and / or be based on determining correct or incorrect reception of subject transmission / s, e.g. based on error coding and / or based on scheduling assignment / s scheduling the subject transmissions. Transmitting acknowledgement information may be based on, and / or comprise, a structure for acknowledgement 2320 information to transmit, e.g. the structure of one or more subpatterns, e.g. based on which subject transmission is scheduled for an associated subdivision. Transmitting acknowledgement information may comprise transmitting corresponding signalling, e.g. at one instance and / or in one message and / or one channel, in particular a physical channel, which may be a control channel. In some cases, the channel may be a shared channel 2325 or data channel, e.g. utilising rate-matching of the acknowledgment information. The acknowledgement information may generally pertain to a plurality of subject transmissions, which may be on different channels and / or carriers, and / or may comprise data signalling and / or control signalling. The acknowledgment information may be based on a codebook, which may be based on one or more size indications and / or assignment 2330 indications (representing HARQ structures), which may be received with a plurality of control signallings and / or control messages, e.g. in the same or different transmission timing structures, and / or in the same or different (target) sets of resources. Transmitting acknowledgement information may comprise determining the codebook, e.g. based on control information in one or more control information messages and / or a configuration. 2335 A codebook may pertain to transmitting acknowledgement information at a single and / or specific instant, e.g. a single PUCCH or PUSCH transmission, and / or in one message or with jointly encoded and / or modulated acknowledgement information. Generally, acknowledgment information may be transmitted together with other control information, e.g. a scheduling request and / or measurement information. 2340

[0323] Acknowledgement signalling may in some cases comprise, next to acknowledgement information, other information, e.g. control information, in particular, uplink or sidelink control information, like a scheduling request and / or measurement information, or similar, and / or error detection and / or correction information, respectively associated bits.

[0324] The payload size of acknowledgement signalling may represent the number of bits of ac- 2345 knowledgement information, and / or in some cases the total number of bits carried by the acknowledgement signalling, and / or the number of resource elements needed. Ac-

[0325] P111680W001 65 / 88 knowledgement signalling and / or information may pertain to ARQ and / or HARQ processes; an ARQ process may provide ACK / NACK (and perhaps additional feedback) feedback, and decoding may be performed on each (re-)transmission separately, with- 2350 out soft-buffering / soft-combining intermediate data, whereas HARQ may comprise soft-buffering / soft-combining of intermediate data of decoding for one or more (re-)transmissions.

[0326] Subject transmission may be data signalling or control signalling. The transmission may be on a shared or dedicated channel. Data signalling may be on a data channel, for example on a PDSCH or PSSCH, or on a dedicated data channel, e.g. for low latency and / or 2355 high reliability, e.g. a URLLC channel. Control signalling may be on a control channel, for example on a common control channel or a PDCCH or PSCCH, and / or comprise one or more DCI messages or SCI messages. In some cases, the subject transmission may comprise, or represent, reference signalling. For example, it may comprise DM-RS and / or pilot signalling and / or discovery signalling and / or sounding signalling and / or phase tracking 2360 signalling and / or cell-specific reference signalling and / or user-specific signalling, in particular CSI-RS. A subject transmission may pertain to one scheduling assignment and / or one acknowledgement signalling process (e.g., according to identifier or subidentifier), and / or one subdivision. In some cases, a subject transmission may cross the borders of subdivisions in time, e.g. due to being scheduled to start in one subdivision and extending 2365 into another, or even crossing over more than one subdivision. In this case, it may be considered that the subject transmission is associated to the subdivision it ends in.

[0327] It may be considered that transmitting acknowledgement information, in particular of acknowledgement information, is based on determining whether the subject transmission / s has or have been received correctly, e.g. based on error coding and / or reception quality. 2370 Reception quality may for example be based on a determined signal quality. Acknowledgement information may generally be transmitted to a signalling radio node and / or node arrangement and / or to a network and / or network node.

[0328] Acknowledgement information, or bit / s of a subpattern structure of such information (e.g., an acknowledgement information structure, may represent and / or comprise one or 2375 more bits, in particular a pattern of bits. Multiple bits pertaining to a data structure or substructure or message like a control message may be considered a subpattern. The structure or arrangement of acknowledgement information may indicate the order, and / or meaning, and / or mapping, and / or pattern of bits (or subpatterns of bits) of the information. The structure or mapping may in particular indicate one or more data block 2380 structures, e.g. code blocks and / or code block groups and / or transport blocks and / or messages, e.g. command messages, the acknowledgement information pertains to, and / or which bits or subpattern of bits are associated to which data block structure. In some

[0329] P111680W001 66 / 88 cases, the mapping may pertain to one or more acknowledgement signalling processes, e.g. processes with different identifiers, and / or one or more different data streams. The config- 2385 uration or structure or codebook may indicate to which process / es and / or data stream / s the information pertains. Generally, the acknowledgement information may comprise one or more subpatterns, each of which may pertain to a data block structure, e.g. a code block or code block group or transport block. A subpattern may be arranged to indicate acknowledgement or non-acknowledgement, or another retransmission state like 2390 non-scheduling or non-reception, of the associated data block structure. It may be considered that a subpattern comprises one bit, or in some cases more than one bit. It should be noted that acknowledgement information may be subjected to significant processing before being transmitted with acknowledgement signalling. Different configurations may indicate different sizes and / or mapping and / or structures and / or pattern. 2395

[0330] An acknowledgment signalling process (providing acknowledgment information) may be a HARQ process, and / or be identified by a process identifier, e.g. a HARQ process identifier or sub-identifier. Acknowledgement signalling and / or associated acknowledgement information may be referred to as feedback or acknowledgement feedback. It should be noted that data blocks or structures to which subpatterns may pertain may be intended 2400 to carry data (e.g., information and / or systemic and / or coding bits). However, depending on transmission conditions, such data may be received or not received (or not received correctly), which may be indicated correspondingly in the feedback. In some cases, a subpattern of acknowledgement signalling may comprise padding bits, e.g. if the acknowledgement information for a data block requires fewer bits than indicated as size of 2405 the subpattern. Such may for example happen if the size is indicated by a unit size larger than required for the feedback.

[0331] Acknowledgment information may generally indicate at least ACK or NACK, e.g. pertaining to an acknowledgment signalling process, or an element of a data block structure like a data block, subblock group or subblock, or a message, in particular a control mes- 2410 sage. Generally, to an acknowledgment signalling process there may be associated one specific subpattern and / or a data block structure, for which acknowledgment information may be provided. Acknowledgement information may comprise a plurality of pieces of information, represented in a plurality of ARQ and / or HARQ structures.

[0332] An acknowledgment signalling process may determine correct or incorrect reception, 2415 and / or corresponding acknowledgement information, of a data block like a transport block, and / or substructures thereof, based on coding bits associated to the data block, and / or based on coding bits associated to one or more data block and / or subblocks and / or subblock group / s. Acknowledgement information (determined by an acknowl-

[0333] P111680W001 67 / 88 edgement signalling process) may pertain to the data block as a whole, and / or to one 2420 or more subblocks or subblock groups. A code block may be considered an example of a subblock, whereas a code block group may be considered an example of a subblock group. Accordingly, the associated subpattern may comprise one or more bits indicating reception status or feedback of the data block, and / or one or more bits indicating reception status or feedback of one or more subblocks or subblock groups. Each subpattern 2425 or bit of the subpattern may be associated and / or mapped to a specific data block or subblock or subblock group. In some variants, correct reception for a data block may be indicated if all subblocks or subblock groups are correctly identified. In such a case, the subpattern may represent acknowledgement information for the data block as a whole, reducing overhead in comparison to provide acknowledgement information for the sub- 2430 blocks or subblock groups. The smallest structure (e.g. subblock / subblock group / data block) the subpattern provides acknowledgement information for and / or is associated to may be considered its (highest) resolution. In some variants, a subpattern may provide acknowledgment information regarding several elements of a data block structure and / or at different resolution, e.g. to allow more specific error detection. For example, even if 2435 a subpattern indicates acknowledgment signalling pertaining to a data block as a whole, in some variants higher resolution (e.g., subblock or subblock group resolution) may be provided by the subpattern. A subpattern may generally comprise one or more bits indicating ACK / NACK for a data block, and / or one or more bits for indicating ACK / NACK for a subblock or subblock group, or for more than one subblock or subblock group. 2440

[0334] A subblock and / or subblock group may comprise information bits (representing the data to be transmitted, e.g. user data and / or downlink / sidelink data or uplink data). It may be considered that a data block and / or subblock and / or subblock group also comprises error one or more error detection bits, which may pertain to, and / or be determined based on, the information bits (for a subblock group, the error detection bit / s may be determined 2445 based on the information bits and / or error detection bits and / or error correction bits of the subblock / s of the subblock group). A data block or substructure like subblock or subblock group may comprise error correction bits, which may in particular be determined based on the information bits and error detection bits of the block or substructure, e.g. utilising an error correction coding scheme, in particular for forward error correction (FEC), e.g. 2450 LDPC or polar coding and / or turbo coding. Generally, the error correction coding of a data block structure (and / or associated bits) may cover and / or pertain to information bits and error detection bits of the structure. A subblock group may represent a combination of one or more code blocks, respectively the corresponding bits. A data block may represent a code block or code block group, or a combination of more than one code block groups. 2455 A transport block may be split up in code blocks and / or code block groups, for example

[0335] P111680W001 68 / 88 based on the bit size of the information bits of a higher layer data structure provided for error coding and / or size requirements or preferences for error coding, in particular error correction coding. Such a higher layer data structure is sometimes also referred to as transport block, which in this context represents information bits without the error 2460 coding bits described herein, although higher layer error handling information may be included, e.g. for an internet protocol like TCP. However, such error handling information represents information bits in the context of this disclosure, as the acknowledgement signalling procedures described treat it accordingly.

[0336] In some variants, a subblock like a code block may comprise error correction bits, which 2465 may be determined based on the information bit / s and / or error detection bit / s of the subblock. An error correction coding scheme may be used for determining the error correction bits, e.g. based on LDPC or polar coding or Reed-Mueller coding. In some cases, a subblock or code block may be considered to be defined as a block or pattern of bits comprising information bits, error detection bit / s determined based on the information 2470 bits, and error correction bit / s determined based on the information bits and / or error detection bit / s. It may be considered that in a subblock, e.g. code block, the information bits (and possibly the error correction bit / s) are protected and / or covered by the error correction scheme or corresponding error correction bit / s. A code block group may comprise one or more code blocks. In some variants, no additional error detection bits and / or 2475 error correction bits are applied, however, it may be considered to apply either or both. A transport block may comprise one or more code block groups. It may be considered that no additional error detection bits and / or error correction bits are applied to a transport block, however, it may be considered to apply either or both. In some specific variants, the code block group / s comprise no additional layers of error detection or correction cod- 2480 ing, and the transport block may comprise only additional error detection coding bits, but no additional error correction coding. This may particularly be true if the transport block size is larger than the code block size and / or the maximum size for error correction coding. A subpattern of acknowledgement signalling (in particular indicating ACK or NACK) may pertain to a code block, e.g. indicating whether the code block has been 2485 correctly received. It may be considered that a subpattern pertains to a subgroup like a code block group or a data block like a transport block. In such cases, it may indicate ACK, if all subblocks or code blocks of the group or data / transport block are received correctly (e.g. based on a logical AND operation), and NACK or another state of noncorrect reception if at least one subblock or code block has not been correctly received. It 2490 should be noted that a code block may be considered to be correctly received not only if it actually has been correctly received, but also if it can be correctly reconstructed based on soft-combining and / or the error correction coding.

[0337] P111680W001 69 / 88 A subpattern / HARQ structure may pertain to one acknowledgement signalling process and / or one carrier like a component carrier and / or data block structure or data block. It 2495 may in particular be considered that one (e.g. specific and / or single) subpattern pertains, e.g. is mapped by the codebook, to one (e.g., specific and / or single) acknowledgement signalling process, e.g. a specific and / or single HARQ process. It may be considered that in the bit pattern, subpatterns are mapped to acknowledgement signalling processes and / or data blocks or data block structures on a one-to-one basis. In some variants, there 2500 may be multiple subpatterns (and / or associated acknowledgment signalling processes) associated to the same component carrier, e.g. if multiple data streams transmitted on the carrier are subject to acknowledgement signalling processes. A subpattern may comprise one or more bits, the number of which may be considered to represent its size or bit size. Different bit n-tupels (n being 1 or larger) of a subpattern may be associated 2505 to different elements of a data block structure (e.g., data block or subblock or subblock group), and / or represent different resolutions. There may be considered variants in which only one resolution is represented by a bit pattern, e.g. a data block. A bit n-tupel may represent acknowledgement information (also referred to a feedback), in particular ACK or NACK, and optionally, (if n^,l), may represent DTX / DRX or other reception 2510 states. ACK / NACK may be represented by one bit, or by more than one bit, e.g. to improve disambiguity of bit sequences representing ACK or NACK, and / or to improve transmission reliability.

[0338] The acknowledgement information or feedback information may pertain to a plurality of different transmissions, which may be associated to and / or represented by data block 2515 structures, respectively the associated data blocks or data signalling. The data block structures, and / or the corresponding blocks and / or signalling, may be scheduled for simultaneous transmission, e.g. for the same transmission timing structure, in particular within the same slot or subframe, and / or on the same symbol / s. However, alternatives with scheduling for non-simultaneous transmission may be considered. For example, the 2520 acknowledgment information may pertain to data blocks scheduled for different transmission timing structures, e.g. different slots (or mini-slots, or slots and mini-slots) or similar, which may correspondingly be received (or not or wrongly received). Scheduling signalling may generally comprise indicating resources, e.g. time and / or frequency resources, for example for receiving or transmitting the scheduled signalling. 2525

[0339] Signalling may generally be considered to represent an electromagnetic wave structure (e.g., over a time interval and frequency interval), which is intended to convey information to at least one specific or generic (e.g., anyone who might pick up the signalling) target. A process of signalling may comprise transmitting the signalling. Transmitting signalling, in particular control signalling or communication signalling, e.g. comprising 2530

[0340] P111680W001 70 / 88 or representing acknowledgement signalling and / or resource requesting information, may comprise encoding and / or modulating. Encoding and / or modulating may comprise error detection coding and / or forward error correction encoding and / or scrambling. Receiving control signalling may comprise corresponding decoding and / or demodulation. Error detection coding may comprise, and / or be based on, parity or checksum approaches, e.g. 2535 CRC (Cyclic Redundancy Check). Forward error correction coding may comprise and / or be based on for example turbo coding and / or Reed-Muller coding, and / or polar coding and / or LDPC coding (Low Density Parity Check). The type of coding used may be based on the channel (e.g., physical channel) the coded signal is associated to. A code rate may represent the ratio of the number of information bits before encoding to the number of 2540 encoded bits after encoding, considering that encoding adds coding bits for error detection coding and forward error correction. Coded bits may refer to information bits (also called systematic bits) plus coding bits.

[0341] Communication signalling may comprise, and / or represent, and / or be implemented as, data signalling, and / or user plane signalling. Communication signalling may be associated 2545 to a data channel, e.g. a physical downlink channel or physical uplink channel or physical sidelink channel, in particular a PDSCH (Physical Downlink Shared Channel) or PSSCH (Physical Sidelink Shared Channel). Generally, a data channel may be a shared channel or a dedicated channel. Data signalling may be signalling associated to and / or on a data channel. 2550

[0342] An indication generally may explicitly and / or implicitly indicate the information it represents and / or indicates. Implicit indication may for example be based on position and / or resource used for transmission. Explicit indication may for example be based on a parametrisation with one or more parameters, and / or one or more index or indices, and / or one or more bit patterns representing the information. It may in particular be con- 2555 sidered that control signalling as described herein, based on the utilised resource sequence, implicitly indicates the control signalling type.

[0343] A resource element may generally describe the smallest individually usable and / or encodable and / or decodable and / or modulatable and / or demodulatable time-frequency resource, and / or may describe a time-frequency resource covering a symbol time length in 2560 time and a subcarrier in frequency. A signal may be allocatable and / or allocated to a resource element. A subcarrier may be a subband of a carrier, e.g. as defined by a standard. A carrier may define a frequency and / or frequency band for transmission and / or reception. In some variants, a signal (jointly encoded / modulated) may cover more than one resource elements. A resource element may generally be as defined by a correspond- 2565 ing standard, e.g. NR or LTE. As symbol time length and / or subcarrier spacing (and / or

[0344] P111680W001 71 / 88 numerology) may be different between different symbols and / or subcarriers, different resource elements may have different extension (length / width) in time and / or frequency domain, in particular resource elements pertaining to different carriers.

[0345] A resource generally may represent a time-frequency and / or code resource, on which 2570 signalling, e.g. according to a specific format, may be communicated, for example transmitted and / or received, and / or be intended for transmission and / or reception.

[0346] A border symbol may generally represent a starting symbol or an ending symbol for transmitting and / or receiving. A starting symbol may in particular be a starting symbol of uplink or sidelink signalling, for example control signalling or data signalling. Such 2575 signalling may be on a data channel or control channel, e.g. a physical channel, in particular a physical uplink shared channel (like PUSCH) or a sidelink data or shared channel, or a physical uplink control channel (like PUCCH) or a sidelink control channel.

[0347] If the starting symbol is associated to control signalling (e.g., on a control channel), the control signalling may be in response to received signalling (in sidelink or downlink), e.g. 2580 representing acknowledgement signalling associated thereto, which may be HARQ or ARQ signalling. An ending symbol may represent an ending symbol (in time) of downlink or sidelink transmission or signalling, which may be intended or scheduled for the radio node or user equipment. Such downlink signalling may in particular be data signalling, e.g. on a physical downlink channel like a shared channel, e.g. a PDSCH (Physical Downlink 2585 Shared Channel). A starting symbol may be determined based on, and / or in relation to, such an ending symbol.

[0348] Configuring a radio node, in particular a terminal or user equipment, may refer to the radio node being adapted or caused or set and / or instructed to operate according to the configuration. Configuring may be done by another device, e.g., a network node (for 2590 example, a radio node of the network like a base station or eNodeB) or network, in which case it may comprise transmitting configuration data to the radio node to be configured.

[0349] Such configuration data may represent the configuration to be configured and / or comprise one or more instruction pertaining to a configuration, e.g. a configuration for transmitting and / or receiving on allocated resources, in particular frequency resources. A radio node 2595 may configure itself, e.g., based on configuration data received from a network or network node. A network node may utilise, and / or be adapted to utilise, its circuitry / ies for configuring. Allocation information may be considered a form of configuration data.

[0350] Configuration data may comprise and / or be represented by configuration information, and / or one or more corresponding indications and / or message / s 2600

[0351] Generally, configuring may include determining configuration data representing the configuration and providing, e.g. transmitting, it to one or more other nodes (parallel and / or

[0352] P111680W001 72 / 88 sequentially), which may transmit it further to the radio node (or another node, which may be repeated until it reaches the wireless device). Alternatively, or additionally, configuring a radio node, e.g., by a network node or other device, may include receiving 2605 configuration data and / or data pertaining to configuration data, e.g., from another node like a network node, which may be a higher-level node of the network, and / or transmitting received configuration data to the radio node. Accordingly, determining a configuration and transmitting the configuration data to the radio node may be performed by different network nodes or entities, which may be able to communicate via a suitable interface, e.g., 2610 an X2 interface in the case of LTE or a corresponding interface for NR. Configuring a terminal may comprise scheduling downlink and / or uplink transmissions for the terminal, e.g. downlink data and / or downlink control signalling and / or DCI and / or uplink control or data or communication signalling, in particular acknowledgement signalling, and / or configuring resources and / or a resource pool therefor. 2615

[0353] A resource structure may be considered to be neighboured in frequency domain by another resource structure, if they share a common border frequency, e.g. one as an upper frequency border and the other as a lower frequency border. Such a border may for example be represented by the upper end of a bandwidth assigned to a subcarrier n, which also represents the lower end of a bandwidth assigned to a subcarrier n+1. A resource 2620 structure may be considered to be neighboured in time domain by another resource structure, if they share a common border time, e.g. one as an upper (or right in the figures) border and the other as a lower (or left in the figures) border. Such a border may for example be represented by the end of the symbol time interval assigned to a symbol n, which also represents the beginning of a symbol time interval assigned to a symbol n+1. 2625

[0354] Generally, a resource structure being neighboured by another resource structure in a domain may also be referred to as abutting and / or bordering the other resource structure in the domain.

[0355] A resource structure may general represent a structure in time and / or frequency domain, in particular representing a time interval and a frequency interval. A resource structure 2630 may comprise and / or be comprised of resource elements, and / or the time interval of a resource structure may comprise and / or be comprised of symbol time interval / s, and / or the frequency interval of a resource structure may comprise and / or be comprised of sub-carrier / s. A resource element may be considered an example for a resource structure, a slot or mini-slot or a Physical Resource Block (PRB) or parts thereof may be considered 2635 others. A resource structure may be associated to a specific channel, e.g. a PUSCH or PUCCH, in particular resource structure smaller than a slot or PRB.

[0356] Examples of a resource structure in frequency domain comprise a bandwidth or band, or

[0357] P111680W001 73 / 88 a bandwidth part. A bandwidth part may be a part of a bandwidth available for a radio node for communicating, e.g. due to circuitry and / or configuration and / or regulations 2640 and / or a standard. A bandwidth part may be configured or configurable to a radio node. In some variants, a bandwidth part may be the part of a bandwidth used for communicating, e.g. transmitting and / or receiving, by a radio node. The bandwidth part may be smaller than the bandwidth (which may be a device bandwidth defined by the circuitry / configuration of a device, and / or a system bandwidth, e.g. available for a 2645 RAN). It may be considered that a bandwidth part comprises one or more resource blocks or resource block groups, in particular one or more PRBs or PRB groups. A bandwidth part may pertain to, and / or comprise, one or more carriers.

[0358] A carrier may generally represent a frequency range or band and / or pertain to a central frequency and an associated frequency interval. It may be considered that a carrier com- 2650 prises a plurality of subcarriers. A carrier may have assigned to it a central frequency or center frequency interval, e.g. represented by one or more subcarriers (to each subcarrier there may be generally assigned a frequency bandwidth or interval). Different carriers may be non-overlapping, and / or may be neighbouring in frequency domain.

[0359] It should be noted that the term “radio” in this disclosure may be considered to pertain to 2655 wireless communication in general, and may also include wireless communication utilising millimeter waves, in particular above one of the thresholds 10 GHz or 20 GHz or 50 GHz or 52 GHz or 52.6 GHz or 60 GHz or 72 GHz or 100 GHz or 114 GHz. Such communication may utilise one or more carriers, e.g. in FDD and / or carrier aggregation. Upper frequency boundaries may correspond to 300 GHz or 200 GHz or 120 GHz or any of the thresholds 2660 larger than the one representing the lower frequency boundary.

[0360] A radio node, in particular a network node or a terminal, may generally be any device adapted for transmitting and / or receiving radio and / or wireless signals and / or data, in particular communication data, in particular on at least one carrier. The at least one carrier may comprise a carrier accessed based on an LBT procedure (which may be called 2665 LBT carrier), e.g., an unlicensed carrier. It may be considered that the carrier is part of a carrier aggregate.

[0361] Receiving or transmitting on a cell or carrier may refer to receiving or transmitting utilizing a frequency (band) or spectrum associated to the cell or carrier. A cell may generally comprise and / or be defined by or for one or more carriers, in particular at least one car- 2670 rier for UL communication / transmission (called UL carrier) and at least one carrier for DL communication / transmission (called DL carrier). It may be considered that a cell comprises different numbers of UL carriers and DL carriers. Alternatively, or additionally, a cell may comprise at least one carrier for UL communication / transmission and DL

[0362] P111680W001 74 / 88 communication / transmission, e.g., in TDD-based approaches. 2675

[0363] A channel may generally be a logical, transport or physical channel. A channel may comprise and / or be arranged on one or more carriers, in particular a plurality of subcarriers.

[0364] A channel carrying and / or for carrying control signalling / control information may be considered a control channel, in particular if it is a physical layer channel and / or if it carries control plane information. Analogously, a channel carrying and / or for carrying data sig- 2680 nailing / user information may be considered a data channel, in particular if it is a physical layer channel and / or if it carries user plane information. A channel may be defined for a specific communication direction, or for two complementary communication directions (e.g., UL and DL, or sidelink in two directions), in which case it may be considered to have two component channels, one for each direction. Examples of channels comprise a 2685 channel for low latency and / or high reliability transmission, in particular a channel for Ultra- Reliable Low Latency Communication (URLLC), which may be for control and / or data.

[0365] In general, a symbol may represent and / or be associated to a symbol time length, which may be dependent on the carrier and / or subcarrier spacing and / or numerology of the 2690 associated carrier. Accordingly, a symbol may be considered to indicate a time interval having a symbol time length in relation to frequency domain. A symbol time length may be dependent on a carrier frequency and / or bandwidth and / or numerology and / or subcarrier spacing of, or associated to, a symbol. Accordingly, different symbols may have different symbol time lengths. In particular, numerologies with different subcarrier 2695 spacings may have different symbol time length. Generally, a symbol time length may be based on, and / or include, a guard time interval or cyclic extension, e.g. prefix or postfix.

[0366] A sidelink may generally represent a communication channel (or channel structure) between two UEs and / or terminals, in which data is transmitted between the participants (UEs and / or terminals) via the communication channel, e.g. directly and / or without 2700 being relayed via a network node. A sidelink may be established only and / or directly via air interface / s of the participant, which may be directly linked via the sidelink communication channel. In some variants, sidelink communication may be performed without interaction by a network node, e.g. on fixedly defined resources and / or on resources negotiated between the participants. Alternatively, or additionally, it may be considered 2705 that a network node provides some control functionality, e.g. by configuring resources, in particular one or more resource pool / s, for sidelink communication, and / or monitoring a sidelink, e.g. for charging purposes.

[0367] Sidelink communication may also be referred to as device-to-device (D2D) communication, and / or in some cases as ProSe (Proximity Services) communication, e.g. in the context 2710

[0368] P111680W001 75 / 88 of LTE. A sidelink may be implemented in the context of V2x communication (Vehicular communication), e.g. V2V (Vehicle-to- Vehicle), V2I (Vehicle-to-Infrastructure) and / or V2P (Vehicle-to- Person). Any device adapted for sidelink communication may be considered a user equipment or terminal.

[0369] A sidelink communication channel (or structure) may comprise one or more (e.g., physical 2715 or logical) channels, e.g. a PSCCH (Physical Sidelink Control CHannel, which may for example carry control information like an acknowledgement position indication, and / or a PSSCH (Physical Sidelink Shared CHannel, which for example may carry data and / or acknowledgement signalling). It may be considered that a sidelink communication channel (or structure) pertains to and / or used one or more carrier / s and / or frequency range / s 2720 associated to, and / or being used by, cellular communication, e.g. according to a specific license and / or standard. Participants may share a (physical) channel and / or resources, in particular in frequency domain and / or related to a frequency resource like a carrier) of a sidelink, such that two or more participants transmit thereon, e.g. simultaneously, and / or time-shifted, and / or there may be associated specific channels and / or resources 2725 to specific participants, so that for example only one participant transmits on a specific channel or on a specific resource or specific resources, e.g., in frequency domain and / or related to one or more carriers or subcarriers.

[0370] A sidelink may comply with, and / or be implemented according to, a specific standard, e.g. an LTE-based standard and / or NR. A sidelink may utilise TDD (Time Division 2730 Duplex) and / or FDD (Frequency Division Duplex) technology, e.g. as configured by a network node, and / or preconfigured and / or negotiated between the participants. A user equipment may be considered to be adapted for sidelink communication if it, and / or its radio circuitry and / or processing circuitry, is adapted for utilising a sidelink, e.g. on one or more frequency ranges and / or carriers and / or in one or more formats, in particular 2735 according to a specific standard. It may be generally considered that a Radio Access Network is defined by two participants of a sidelink communication. Alternatively, or additionally, a Radio Access Network may be represented, and / or defined with, and / or be related to a network node and / or communication with such a node.

[0371] Communication or communicating may generally comprise transmitting and / or receiv- 2740 ing signalling. Communication on a sidelink (or sidelink signalling) may comprise utilising the sidelink for communication (respectively, for signalling). Sidelink transmission and / or transmitting on a sidelink may be considered to comprise transmission utilising the sidelink, e.g. associated resources and / or transmission formats and / or circuitry and / or the air interface. Sidelink reception and / or receiving on a sidelink may be considered 2745 to comprise reception utilising the sidelink, e.g. associated resources and / or transmis-

[0372] P111680W001 76 / 88 sion formats and / or circuitry and / or the air interface. Sidelink control information (e.g., SCI) may generally be considered to comprise control information transmitted utilising a sidelink.

[0373] Generally, carrier aggregation (CA) may refer to the concept of a radio connection and / or 2750 communication link between a wireless and / or cellular communication network and / or network node and a terminal or on a sidelink comprising a plurality of carriers for at least one direction of transmission (e.g. DL and / or UL), as well as to the aggregate of carriers.

[0374] A corresponding communication link may be referred to as carrier aggregated communication link or CA communication link; carriers in a carrier aggregate may be referred to 2755 as component carriers (CC). In such a link, data may be transmitted over more than one of the carriers and / or all the carriers of the carrier aggregation (the aggregate of carriers). A carrier aggregation may comprise one (or more) dedicated control carriers and / or primary carriers (which may e.g. be referred to as primary component carrier or PCC), over which control information may be transmitted, wherein the control information may 2760 refer to the primary carrier and other carriers, which may be referred to as secondary carriers (or secondary component carrier, SCC). However, in some approaches, control information may be sent over more than one carrier of an aggregate, e.g. one or more PCCs and one PCC and one or more SCCs.

[0375] A transmission may generally pertain to a specific channel and / or specific resources, 2765 in particular with a starting symbol and ending symbol in time, covering the interval therebetween. A scheduled transmission may be a transmission scheduled and / or expected and / or for which resources are scheduled or provided or reserved. However, not every scheduled transmission has to be realized. For example, a scheduled downlink transmission may not be received, or a scheduled uplink transmission may not be transmitted due to 2770 power limitations, or other influences (e.g., a channel on an unlicensed carrier being occupied). A transmission may be scheduled for a transmission timing substructure (e.g., a mini-slot, and / or covering only a part of a transmission timing structure) within a transmission timing structure like a slot. A border symbol may be indicative of a symbol in the transmission timing structure at which the transmission starts or ends. 2775

[0376] Predefined in the context of this disclosure may refer to the related information being defined for example in a standard, and / or being available without specific configuration from a network or network node, e.g. stored in memory, for example independent of being configured. Configured or configurable may be considered to pertain to the corresponding information being set / configured, e.g. by the network or a network node. 2780

[0377] A configuration or schedule, like a mini-slot configuration and / or structure configuration, may schedule transmissions, e.g. for the time / transmissions it is valid, and / or transmis-

[0378] P111680W001 77 / 88 sions may be scheduled by separate signalling or separate configuration, e.g. separate RRC signalling and / or downlink control information signalling. The transmission / s scheduled may represent signalling to be transmitted by the device for which it is scheduled, or 2785 signalling to be received by the device for which it is scheduled, depending on which side of a communication the device is. It should be noted that downlink control information or specifically DCI signalling may be considered physical layer signalling, in contrast to higher layer signalling like MAC (Medium Access Control) signalling or RRC layer signalling. The higher the layer of signalling is, the less frequent / the more time / resource 2790 consuming it may be considered, at least partially due to the information contained in such signalling having to be passed on through several layers, each layer requiring processing and handling.

[0379] A scheduled transmission, and / or transmission timing structure like a mini-slot or slot, may pertain to a specific channel, in particular a physical uplink shared channel, a physical 2795 uplink control channel, or a physical downlink shared channel, e.g. PUSCH, PUCCH or PDSCH, and / or may pertain to a specific cell and / or carrier aggregation. A corresponding configuration, e.g. scheduling configuration or symbol configuration may pertain to such channel, cell and / or carrier aggregation. It may be considered that the scheduled transmission represents transmission on a physical channel, in particular a shared phys- 2800 ical channel, for example a physical uplink shared channel or physical downlink shared channel. For such channels, semi-persistent configuring may be particularly suitable.

[0380] Generally, a configuration may be a configuration indicating timing, and / or be represented or configured with corresponding configuration data. A configuration may be embedded in, and / or comprised in, a message or configuration or corresponding data, which may 2805 indicate and / or schedule resources, in particular semi-persistently and / or semi-statically.

[0381] A control region of a transmission timing structure may be an interval in time and / or frequency domain for intended or scheduled or reserved for control signalling, in particular downlink control signalling, and / or for a specific control channel, e.g. a physical downlink control channel like PDCCH. The interval may comprise, and / or consist of, a number of 2810 symbols in time, which may be configured or configurable, e.g. by (UE-specific) dedicated signalling (which may be single-cast, for example addressed to or intended for a specific UE), e.g. on a PDCCH, or RRC signalling, or on a multicast or broadcast channel.

[0382] In general, the transmission timing structure may comprise a control region covering a configurable number of symbols. It may be considered that in general the border symbol is 2815 configured to be after the control region in time. A control region may be associated, e.g. via configuration and / or determination, to one or more specific UEs and / or formats of PDCCH and / or DCI and / or identifiers, e.g. UE identifiers and / or RNTIs or carrier / cell

[0383] P111680W001 78 / 88 identifiers, and / or be represented and / or associated to a CORESET and / or a search space. 2820

[0384] The duration of a symbol (symbol time length or interval) of the transmission timing structure may generally be dependent on a numerology and / or carrier, wherein the numerology and / or carrier may be configurable. The numerology may be the numerology to be used for the scheduled transmission.

[0385] A transmission timing structure may comprise a plurality of symbols, and / or define an 2825 interval comprising several symbols (respectively their associated time intervals). In the context of this disclosure, it should be noted that a reference to a symbol for ease of reference may be interpreted to refer to the time domain projection or time interval or time component or duration or length in time of the symbol, unless it is clear from the context that the frequency domain component also has to be considered. Examples of transmis- 2830 sion timing structures include slot, subframe, mini-slot (which also may be considered a substructure of a slot), slot aggregation (which may comprise a plurality of slots and may be considered a superstructure of a slot), respectively their time domain component. A transmission timing structure may generally comprise a plurality of symbols defining the time domain extension (e.g., interval or length or duration) of the transmission timing 2835 structure, and arranged neighboring to each other in a numbered sequence. A timing structure (which may also be considered or implemented as synchronisation structure) may be defined by a succession of such transmission timing structures, which may for example define a timing grid with symbols representing the smallest grid structures. A transmission timing structure, and / or a border symbol or a scheduled transmission may 2840 be determined or scheduled in relation to such a timing grid. A transmission timing structure of reception may be the transmission timing structure in which the scheduling control signalling is received, e.g. in relation to the timing grid. A transmission timing structure may in particular be a slot or subframe or in some cases, a mini-slot.

[0386] Feedback signalling may be considered a form or control signalling, e.g. uplink or sidelink 2845 control signalling, like UCI (Uplink Control Information) signalling or SCI (Sidelink Control Information) signalling. Feedback signalling may in particular comprise and / or represent acknowledgement signalling and / or acknowledgement information and / or measurement reporting.

[0387] signalling utilising, and / or on and / or associated to, resources or a resource structure may 2850 be signalling covering the resources or structure, signalling on the associated frequency / ies and / or in the associated time interval / s. It may be considered that a signalling resource structure comprises and / or encompasses one or more substructures, which may be associated to one or more different channels and / or types of signalling and / or comprise

[0388] P111680W001 79 / 88 one or more holes (resource element / s not scheduled for transmissions or reception of 2855 transmissions). A resource substructure, e.g. a feedback resource structure, may generally be continuous in time and / or frequency, within the associated intervals. It may be considered that a substructure, in particular a feedback resource structure, represents a rectangle filled with one or more resource elements in time / frequency space. However, in some cases, a resource structure or substructure, in particular a frequency resource 2860 range, may represent a non-continuous pattern of resources in one or more domains, e.g. time and / or frequency. The resource elements of a substructure may be scheduled for associated signalling.

[0389] Example types of signalling comprise signalling of a specific communication direction, in particular, uplink signalling, downlink signalling, sidelink signalling, as well as reference 2865 signalling (e.g., SRS or CRS or CSI-RS), communication signalling, control signalling, and / or signalling associated to a specific channel like PUSCH, PDSCH, PUCCH, PDCCH, PSCCH, PSSCH, etc.).

[0390] In the context of this disclosure, there may be distinguished between dynamically scheduled or aperiodic transmission and / or configuration, and semi-static or semi-persistent or 2870 periodic transmission and / or configuration. The term “dynamic” or similar terms may generally pertain to configuration / transmission valid and / or scheduled and / or configured for (relatively) short timescales and / or a (e.g., predefined and / or configured and / or limited and / or definite) number of occurrences and / or transmission timing structures, e.g. one or more transmission timing structures like slots or slot aggregations, and / or for one 2875 or more (e.g., specific number) of transmission / occurrences. Dynamic configuration may be based on low-level signalling, e.g. control signalling on the physical layer and / or MAC layer, in particular in the form of DCI or SCI. Periodic / semi-static may pertain to longer timescales, e.g. several slots and / or more than one frame, and / or a non-defined number of occurrences, e.g., until a dynamic configuration contradicts, or until a new periodic 2880 configuration arrives. A periodic or semi-static configuration may be based on, and / or be configured with, higher-layer signalling, in particular RRC layer signalling and / or RRC signalling and / or MAC signalling.

[0391] In this disclosure, for purposes of explanation and not limitation, specific details are set forth (such as particular network functions, processes and signalling steps) in order to 2885 provide a thorough understanding of the technique presented herein. It will be apparent to one skilled in the art that the present concepts and aspects may be practised in other variants and variants that depart from these specific details.

[0392] For example, the concepts and variants are partially described in the context of Long Term Evolution (LTE) or LTE- Advanced (LTE-A) or New Radio mobile or wireless com- 2890

[0393] P111680W001 80 / 88 munications technologies; however, this does not rule out the use of the present concepts and aspects in connection with additional or alternative mobile communication technologies such as the Global System for Mobile Communications (GSM) or IEEE standards as IEEE 802. Had or IEEE 802.11 ay. While described variants may pertain to certain Technical Specifications (TSs) of the Third Generation Partnership Project (3GPP), it will be 2895 appreciated that the present approaches, concepts and aspects could also be realized in connection with different Performance Management (PM) specifications.

[0394] Moreover, those skilled in the art will appreciate that the services, functions and steps explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, or using an Application Specific Integrated Circuit (ASIC), 2900 a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA) or general purpose computer. It will also be appreciated that while the variants described herein are elucidated in the context of methods and devices, the concepts and aspects presented herein may also be embodied in a program product as well as in a system comprising control circuitry, e.g. a computer processor and a memory coupled to the processor, 2905 wherein the memory is encoded with one or more programs or program products that execute the services, functions and steps disclosed herein.

[0395] It is believed that the advantages of the aspects and variants presented herein will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, constructions and arrangement of the exemplary aspects thereof 2910 without departing from the scope of the concepts and aspects described herein or without sacrificing all of its advantageous effects. The aspects presented herein can be varied in many ways.

[0396] P111680W001 81 / 88 Some useful abbreviations comprise

[0397] Abbreviation Explanation

[0398] ABF Analog beamformer, fanout to antenna+beamforming ACK / NACK Acknowledgment / Negative Acknowledgement Ant Antenna

[0399] AoA Angle of Arrival

[0400] ARQ Automatic Repeat reQuest

[0401] BB BaseBand

[0402] Beamindex IF beamindex interface

[0403] BER Bit Error Rate

[0404] BI Beam Index

[0405] BLER Block Error Rate

[0406] BPSK Binary Phase Shift Keying

[0407] BWP BandWidth Part

[0408] CAZAC Constant Amplitude Zero Cross Correlation

[0409] CB Code Block

[0410] CBB Code Block Bundle

[0411] CBG Code Block Group

[0412] CDM Code Division Multiplex

[0413] CM Cubic Metric

[0414] CNN Convolution Neural Network

[0415] Comm RXBB communication receiver baseband

[0416] CORESET Control Resource Set

[0417] CP Cyclic Prefix

[0418] CP rem CP removal

[0419] CQI Channel Quality Information

[0420] CRC Cyclic Redundancy Check

[0421] CRS Common reference signal

[0422] CSI Channel State Information

[0423] CSI-RS Channel state information reference signal

[0424] DAI Downlink Assignment Indicator

[0425] DCI Downlink Control Information

[0426] DFE Digital Frontend

[0427] DFT Discrete Fourier Transform

[0428] DFTS-FDM DFT-spread-FDM

[0429] DM(-)RS Demodulation reference signal(ing)

[0430] DOP Dilution of Precision

[0431] P111680W001 82 / 88 eMBB enhanced Mobile BroadBand

[0432] FDD Frequency Division Duplex

[0433] FDE Frequency Domain Equalisation

[0434] FDF Frequency Domain Filtering

[0435] FDM Frequency Division Multiplex

[0436] FFT Fast Fourier Transform

[0437] GPIO General Purpose Input Output

[0438] HARQ Hybrid Automatic Repeat Request

[0439] IAB Integrated Access and Backhaul

[0440] IFFT Inverse Fast Fourier Transform

[0441] Im Imaginary part, e.g. for pi / 2*BPSK modulation

[0442] IR Impulse Response

[0443] ISAC Integrated Sensing and Communication

[0444] ISI Inter Symbol Interference

[0445] JCAS Joint Communication and Sensing

[0446] MBB Mobile Broadband

[0447] MCS Modulation and Coding Scheme

[0448] MIMO Multiple-input-multiple-output

[0449] MRC Maximum-ratio combining

[0450] MRT Maximum-ratio transmission

[0451] MU-MIMO Multiuser multiple- input-multiple-output

[0452] OFDM / A Orthogonal Frequency Division Multiplex / Multiple Access PAPR Peak to Average Power Ratio

[0453] PDCCH Physical Downlink Control Channel

[0454] PDSCH Physical Downlink Shared Channel

[0455] PRACH Physical Random Access CHannel

[0456] PRB Physical Resource Block

[0457] PRS Positioning Reference Signal(ing)

[0458] PUCCH Physical Uplink Control Channel

[0459] PUSCH Physical Uplink Shared Channel

[0460] (P)SCCH (Physical) Sidelink Control Channel

[0461] PSS Primary Synchronisation Signal(ing)

[0462] PT-RS Phase Tracking Reference signalling

[0463] (P)SSCH (Physical) Sidelink Shared Channel

[0464] QAM Quadrature Amplitude Modulation

[0465] occ Orthogonal Cover Code

[0466] OTA Over-The-Air

[0467] QPSK Quadrature Phase Shift Keying

[0468] P111680W001 83 / 88 PSD Power Spectral Density

[0469] RAN Radio Access Network

[0470] RAT Radio Access Technology

[0471] RB Resource Block

[0472] RCS Radar Cross Section

[0473] RE Resource Element

[0474] Re Real part (e.g., for pi / 2*BPSK) modulation

[0475] RF Radio Frequency

[0476] RNTI Radio Network Temporary Identifier

[0477] RRC Radio Resource Control

[0478] RX Receiver, Reception, Reception-related / side

[0479] SA Scheduling Assignment

[0480] SC-FDE Single Carrier Frequency Domain Equalisation

[0481] SC-FDM / A Single Carrier Frequency Division Multiplex / Multiple Access SCI Sidelink Control Information

[0482] SINR Signal-to-interference-plus-noise ratio

[0483] SIR Signal-to-interference ratio

[0484] SNR Signal-to-noise-ratio

[0485] SPI Serial to Parallel Interface

[0486] SR Scheduling Request

[0487] SRS Sounding Reference Signal(ing)

[0488] SSS Secondary Synchronisation Signal(ing)

[0489] SVD Singular- value decomposition

[0490] TB Transport Block

[0491] TDD Time Division Duplex

[0492] TDM Time Division Multiplex

[0493] ToF Time of Flight

[0494] T-RS Tracking Reference signalling or Timing Reference signalling TX Transmitter, Transmission, Transmission-related / side UCI Uplink Control Information

[0495] UDC Up-Down Converter, mixing from BB→RF

[0496] UE User Equipment

[0497] URLLC Ultra Low Latency High Reliability Communication

[0498] VL-MIMO Very- large multiple-input-multiple-output

[0499] WD Wireless Device

[0500] Wfg Waveform Generator

[0501] ZC Zadoff-Chu

[0502] ZF Zero Forcing

[0503] P111680W001 84 / 88 ZP Zero-Power, e.g. muted CSI-RS symbol

[0504] 2915 Abbreviations may be considered to follow 3GPP usage if applicable.

[0505] P111680W001 85 / 88

Claims

CLAIMS1. Method of operating a radio node in a wireless communication network, the radio node being adapted for wireless communication, and being adapted for sensing and / or radar operation, the method comprising performing sensing operation based on sensing 2920 synchronisation signalling multiplexed with sensing signalling, the sensing synchronisation signalling being transmitted on a reference channel determined based on channel sounding.

2. Radio node for a wireless communication network, the radio node being adapted for wireless communication, and being adapted for sensing and / or radar operation, the radio node being adapted for performing sensing operation based on sensing synchronisation 2925 signalling multiplexed with sensing signalling, the sensing synchronisation signalling being transmitted on a reference channel determined based on channel sounding.

3. Method or device according to one of the preceding claims, wherein the sensing synchronisation signalling and the sensing signalling are orthogonalised.

4. Method or device according to one of the preceding claims, wherein the sensing synchro- 2930 nisation signalling is multiplexed with the sensing signalling based on frequency domain multiplexing.

5. Method or device according to one of the preceding claims, wherein the sensing synchronisation signalling is multiplexed with the sensing signalling based on time domain multiplexing. 29356. Method or device according to one of the preceding claims, wherein the sensing synchronisation signalling is multiplexed with the sensing signalling based on code domain multiplexing.

7. Method or device according to one of the preceding claims, wherein the channel sounding is performed with the radio node as end point. 29408. Method or device according to one of the preceding claims, wherein the reference channel is one of a set of reference channels.

9. Method or device according to one of the preceding claims, wherein the sensing synchronisation signalling and the sensing signalling are transmitted based on a set of shared transmission parameters. 294510. Method or device according to one of the preceding claims, wherein the sensing synchronisation signalling and the sensing signalling are transmitted and / or received based on different transmission and / or reception beams.P111680W001 86 / 8811. Method or device according to one of the preceding claims, wherein transmission power for the sensing signalling and transmission power for the sensing synchronisation 2950 signalling are different.

12. Program product comprising instructions causing processing circuitry to control and / or perform a method according to one of claims 1 or 3 to 11.

13. Carrier medium arrangement carrying and / or storing a program product according to claim 12. 2955P111680W001 87 / 88

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