Determining a spatial filter of a prach transmission

Abstract

A method is provided for determining a spatial filter to use for a Physical Random Access Channel (PRACH) in an uplink (UL) only network node deployment. The method can include receiving a higher layer message with a PRACH configuration and then receiving a spatial filter indication associated with the PRACH configuration. Based on the spatial filter indication, the wireless communication device can determine one or more spatial filters to use to transmit the PRACH transmission. The spatial filter could be a Sounding Reference Signal (SRS) port or SRS resource. The spatial filter could also be an indication of an SRS Resource Indication (SRI) that indicates to use the same spatial filter as used when transmitting the SRS indicated in the SRI. In another embodiment, the spatial filter indication could indicate to transmit the PRACH in the same spatial filter as used when last transmitting an SRS resource.

Description

DETERMINING A SPATIAL FILTER OF A PRACH TRANSMISSIONRELATED APPLICATIONS

[0001] This application claims the benefit of provisional patent application serial number 63 / 583,031, filed September 15, 2023 and provisional patent application serial number 63 / 548,028, filed November 10, 2023, the disclosures of which are hereby incorporated herein by reference in their entireties.TECHNICAL FIELD

[0002] The present disclosure relates to a method for determining a spatial filter for a Physical Random Access Channel (PRACH) transmission. Specifically, a spatial filter for a PRACH transmission to an uplink only network node in a wireless communication system.BACKGROUNDTime Alignment and uplink synchronization in New Radio (NR)

[0003] Different User Equipments (UEs) or, more generally, wireless communications devices, in the same cell may typically be located at different positions within the cell and then with different distances to the base station (e.g., New Radio gNodeB). The transmissions from different UEs thus suffer from different delays until they reach the base station. In order to make sure that the Uplink (UL) transmissions from a UE reaches the base station within the corresponding receive window for the base station, an uplink timing control procedure is therefore used. This avoids intracell interference occurring, both between UEs assigned to transmit in consecutive subframes and between UEs transmitting on adjacent subcarriers.

[0004] Time alignment of the uplink transmissions is achieved by applying a timing advance at the UE transmitter, relative to the received downlink timing. The main role of this is to counteract differing propagation delays between different UEs, as shown in the example below for a Long Term Evolution (LTE) Enhanced or Evolved Node B (eNodeB): Figure 1 is an exemplary depiction of time alignments of uplink transmissions according to one or more embodiments of the disclosure. In Figure 1, 102 depicts a case without a timing advance, and 104 depicts a case with timing advances.

[0005] In order to achieve the time alignment, to obtain UL synchronization, the base station (e.g., gNodeB, eNodeB) derives the Timing Advance (TA) value that the UE needs to use for the UL transmissions in order to reach the base station within the receive window and indicates this to the UE. When the UE first accesses a cell, it uses the random-access procedure where thereceived Msgl (the Physical Random Access Channel (PRACH) preamble) is used by the base station to determine the UE’s initial TA to use for UL transmissions in the cell. During the connection, the base station then continuously monitors whether the UE needs to advance / delay the UL transmissions, in order to compensate for changes in propagation delay, and indicates to the UE if there is a need to change the timing advance value.

[0006] The initial TA is obtained when the UE performs random access e.g., when performing a transition from Radio Resource Control (RRC) IDLE (or RRC INACTIVE) to RRC CONNECTED state. After a UE has first synchronized its receiver to the downlink transmissions received from the gNodeB (e.g., by monitoring the Synchronization Signal Blocks (SSBs) of the cell the UE wants to access), the initial timing advance is set by the UE transmitting a random access preamble from which the gNodeB estimates the uplink timing value contained within the Random Access Response (RAR) message. This allows the timing advance to be configured by the gNodeB.PRACH Procedure

[0007] Prior to initiation of the physical random access procedure, Layer 1 or physical layer receives from higher layers a set of SS / Physical Broadcasting Channel (PBCH) block indexes and provides to higher layers a corresponding set of Reference Signal Received Power (RSRP) measurements.

[0008] Physical random access procedure is triggered upon request of a PRACH transmission by higher layers or by a Physical Downlink Control Channel (PDCCH) order. A configuration by higher layers for a PRACH transmission includes the following:• A configuration for PRACH transmission according to Third Generation Partnership Project (3GPP) Technical Specification (TS) 38.211• A preamble index, a preamble Smaller Subcarrier Spacing (SCS), PRACH target receive power, a corresponding Random Access (RA) - Radio Network Temporary Identifier (RNTI) (Random Access Channel (RACH) radio network temporary identifier), and a PRACH resource.

[0009] A PRACH preamble is transmitted according to the PRACH configuration with a transmission power on the indicated PRACH resource.

[0010] PRACH configuration can be cell specific or UE specific. Cell specific PRACH configuration is via a RACH-ConfigCommon information element (IE) while UE specific PRACH configuration is done via a RACH-ConfigDedicated IE, both are described in 3gpp TS38.331.

[0011] For Type-1 random access procedure, a UE is provided with a total number, ^preamble’ °f PRACH preambles for both Contention-based Random Access (CBRA) and Contention Free Random Access (CFRA), in each PRACH occasion. The default is64 if it is not configured. The UE is also provided a number N of SS / PBCH block indexes associated with one PRACH occasion and a number R of contention based preambles per SS / PBCH block index per valid PRACH occasion by a parameter called ssb-perRACH- OccasionAndCB-PreamblesPerSSB contained in RACH-ConfigCommon IE.

[0012] If TV < 1 , one SS / PBCH block index is mapped to 1 / / V consecutive valid PRACH occasions and R contention based preambles with consecutive indexes associated with the SS / PBCH block index per valid PRACH occasion start from preamble index 0. An example is shown in Figure64, and 4 SSBs.

[0013] If N > 1, R contention based preambles with consecutive indexes associated with SS / PBCH block index n, 0 < n < N — 1, per valid PRACH occasion start from preamble index n ’ preamble / ^- An example is shown in Figure 3 which is an example of SSB to PRACH preamble mapping N=4, R=4,= 64, and 4 SSBs. For each PRACH occasion,PRACH preambles 0 to 3 are allocated to SSB#0 for CBRA and PRACH preambles 4 to 5 are allocated to SSB#0 for CFRA, PRACH preambles 16 to 19 are allocated to SSB#1 for CBRA and PRACH preambles 20 to 31 are allocated to SSB#1 for CFRA, and so on.

[0014] Association of CFRA preambles with SSBs can also be reconfigured via a higher parameter ssb-perRACH-Occasion in RACH-ConfigDedicated IE, in which the UE is provided with information about a number N of SS / PBCH block indexes associated with one PRACH occasion. The UE may also provide information about a mapping between a SSB or a CSI-RS index and a preamble index in a PRACH occasion.PDCCH Order Initiated RACH Procedure

[0015] A RACH procedure can be initiated by either the gNodeB or the UE. It can be contention based (CB) or contention free (CF). A RACH procedure can be initiated by a PDCCH order sent from the gNodeB to the UE for synchronizing the UE when UL time alignment may have been lost. PDCCH order is carried by DCI format 1-0 when the DCI’s CRC is scrambled by a UE’s C-RNTI (Cell Radio Network Temporary Identifier) and the "Frequency domain resource assignment" field of the DCI contains all ones. The PDCCH order contains the following information:• Random Access Preamble index: 6 bits according to a higher layer parameter “ra- Preamblelndex” in Clause 5.1.2 of 3GPP TS38.321.• SS / PBCH index: 6 bits, If the value of the "Random Access Preamble index" is not all zeros, this field indicates the SS / PBCH that shall be used to determine a RACH (random access channel) occasion for PRACH (Physical random access channel) transmission; otherwise, this field is reserved.• PRACH Mask index. If the value of the "Random Access Preamble index" is not all zeros, this field indicates the RACH occasion associated with the SS / PBCH indicated by "SS / PBCH index" for the PRACH transmission, according to Clause 5.1.1 of 3GPP TS38.321 ; otherwise, this field is reserved.

[0016] If the PRACH preamble index is non- zero, a contention free random access (CFRA) procedure is triggered, in which the PRACH preamble is allocated only for the UE in a corresponding PRACH resource.

[0017] If the PRACH preamble index is zero, and CFRA PRACH resources associated with SSBs have been provided in a UE specific RACH configuration in rach-ConfigDedicated IE, UE first select an SSB with SS-RSRP (SSB based Reference Signal Received Power) above a configured threshold, then select a PRACH preamble according to the selected SSB. If the PRACH preamble index is zero, and CFRA resources associated with CSI-RSs have been provided in rach-ConfigDedicated IE, UE first select an CSI-RS with CSI-RSRP above a configured threshold, rsrp-ThresholdCSI-RS, then select a PRACH preamble according to the selected CSI-RS. If the PRACH preamble index is zero and the CFRA PRACH resources associated with SSB or CSI-RS are not provided, a contention-based random access (CBRA) procedure is triggered by the PDCCH order, in which the UE selects a PRACH preamble randomly from a set of PRACH preambles configured for CBRA in the serving cell. Note that in this case, the same preamble could be selected by more than one UE in the same PRACH resource and contention could occur. PDCCH order triggered CBRA is only allowed for a SpCell, i.e., a primary cell in either a master cell group (MCG) or a secondary cell group (SCG), if cell groups are configured. The rach-ConfigDedicated IE is described in 3gpp TS38.331, the detailed procedure is described in 3GP TS38.321 section 5.1.2.

[0018] If a UE is configured with two UL carriers for a serving cell and the UE detects a PDCCH order, the UE uses the UL / SUL indicator field value from the detected PDCCH order to determine the UL carrier for the corresponding PRACH transmission.

[0019] A RACH occasion is a time and frequency resource (i.e., a number of RBs in a number of OFDM symbols) allocated for PRACH transmission, multiple RACH occasions maybe configured in a PRACH configuration period consisting multiple radio frames. RACH occasions may be multiplexed either in time or frequency.

[0020] From the physical layer perspective, the random access procedure triggered by a PDCCH order includes the transmission of random access preamble (Msgl) in a PRACH by a UE, the transmission of RAR (RACH response) message with a PDCCH and a corresponding PDSCH (Msg2), and when applicable, the transmission of a PUSCH scheduled by a RAR UL grant, and PDSCH for contention resolution if the RACH procedure is contention based.Rel-18 timing advance enhancements for multi-DCI based multi-Transmission Reception Point (TRP)

[0021] For multi-TRP operation with poorly synchronized TRPs and / or large inter-TRP distances, the DL timing difference between two TRPs can exceed a cyclic prefix (CP). When a single timing advance is used for UL transmissions toward both TRPs, a large UL timing offset can occur at one of the two TRPs, which can cause poor UL performance. To mitigate this issue, two TAs for multi-DCI multi-TRP operation are being specified in NR Rel-18. As part of this, two timing advance groups (TAG)s are introduced per serving cell, where each TAG is associated to one TRP. In addition, two DL reference timings are supported, where each DL reference timing is associated to one TAG. The initial TA for the Two-TA operation is acquired via PDCCH order initiating Contention Free RACH (CFRA) process. A SSB index associated to a target TRP is indicated in the PDCCH order plus additional PCI info in case of inter-cell operation, and the UE is expected to transmit a PRACH toward the TRP associated to the SSB index.UL-Only Nodes

[0022] It is expected that the demand on capacity and user throughput will increase in the future. It is also expected that UL will become a limiting factor, partly due to the natural imbalance of spectral efficiency between UL and DL (which comes from for instance different number antennas, different power levels, etc.) but also partly due to an increase of UL heavy services like gaming, V2V communication, etc.

[0023] A potential remedy to this is to densify the networks more in the UL than in the DL. This may be done by for instance providing radio nodes that only receive in the UL (they do hence not perform any DL transmissions). We will refer to such a transmission node as an “UL- only node” herein. By using such UL-only nodes one could consequently enhance the UL without enhancing the DL. While there is obviously no direct improvement in downlinkperformance, as compared to normal DL+UL nodes, benefits of UL-only nodes include lower complexity, lower weight, smaller volumes, ease of deployment and avoiding the need for permits to deploy radio transmitters.SRS Antenna Switching

[0024] Since it is desirable for the gNB to sound all UE antennas (where sounding an antenna means transmitting an SRS from that antenna, which, in turn, enables the gNB to estimate the channel between said UE antenna and the antennas at the gNB) but costly to equip the UE with many transmit ports, SRS antenna switching was introduced in NR Rel-15, for several different UE architectures for which the number of receive chains is larger than the number of transmit chains. If a UE supports antenna switching, it will report so by means of UE- capability signaling.

[0025] The left column of Table 1 (from 3GPP 38.306) lists SRS antenna-switching capabilities that can be reported from a UE in NR Rel-15. For example, if a UE reports tlr2 in the UE-capability signaling, it means that it has two receive antennas (i.e., two receive chains) but only has the possibility of transmitting from one of those antennas at a time (i.e., one transmit chain) with support for antenna switching. In this case, two single-port SRS resources can be configured to the UE such that it can sound both receive ports using a single transmit port with an antenna switch in between. If a UE reports t2r2 it means that the UE has two receive antennas (i.e., two receive chains) and two transmit antennas (i.e., two transmit chains) with the possibility of transmitting from both of those antennas at the same time.

[0026] Additional UE capabilities were further introduced in NR Rel-16, see right column of Table 1, which indicates support for the UE to be configured with SRS resource set(s) with usage ‘antennaSwitching ’ but where only a subset of all UE antennas is sounded. For example, the UE capability tlrl-tlr2 means that the gNB can configure one single-port SRS resource (same as no antenna-switching capability) or two single-port SRS resources (same as for the capability “lt2r” described above) with usage ‘ antennaSwitching’ per SRS resource set. In this case, if the UE is configured with a single SRS resource (no antenna switching) it will only sound only one of its two antennas, which will save UE power consumption at the cost of reduced channel knowledge at the gNB (since the gNB can only estimate the channel between itself and the UE based on one of the two UE antennas).

[0027] The UE can be configured with one or more SRS resource sets with usage ‘antennaSwitching’, and when triggered with transmission of such SRS resource set(s) the UE should transmit one SRS per UE antenna, until all the SRS in the SRS resource set has beentransmitted. If the total number of SRSs in the SRS resource set(s) with usage ‘antennaSwitching’ is equal to the number of UE antennas, the network will be able to sound the channel for all the UE antennas.

[0028] Table 1: SRS antenna-switching capabilities supported by the UESUMMARY

[0029] A method is provided for determining a spatial filter to use for a Physical Random Access Channel (PRACH) in an uplink (UL) only network node deployment. The method can include receiving a higher layer message with a PRACH configuration, and then receiving a spatial filter indication associated with the PRACH configuration. Based on the spatial filter indication, the wireless communication device can determine one or more spatial filters to use to transmit the PRACH transmission. The spatial filter could be a Sounding Reference Signal (SRS) port or SRS resource. The spatial filter could also be an indication of an SRS Resource Indication (SRI) that indicates the wireless communication device transmits the PRACH in the same spatial filter as used when transmitting the SRS indicated in the SRI. In another embodiment, the spatial filter indication could indicate that the wireless communication device transmits the PRACH in the same spatial filter as used when last transmitting an SRS on an SRS resource, where the SRS resource is used as a spatial relation for an applied UL transmission configuration indicator (TCI) state.

[0030] In an embodiment, a method is provided that is implemented in a wireless communication device for determining a spatial filter for a PRACH transmission. The method includes receiving a message comprising a PRACH configuration. The method also includes receiving a spatial filter indication associated with the PRACH configuration. The method also includes, based on the spatial filter indication, determining one or more spatial filters for a PRACH transmission. The method also includes transmitting the PRACH transmission using the one or more spatial filters.

[0031] In an embodiment, a wireless communication device is provided that is configured to determine a spatial filter for a PRACH transmission, the wireless communication device comprising a radio interface and processing circuitry configured to receive a message comprisinga PRACH configuration, wherein the message is associated with a layer higher than a physical layer. The processing circuitry is also configured to receive a spatial filter indication associated with the PRACH configuration. The processing circuitry is also configured to, based on the spatial filter indication, determine one or more spatial filters for a PRACH transmission The processing circuitry is also configured to transmit the PRACH transmission using the one or more spatial filters.

[0032] According to some embodiments, a method of operating a communication device is provided. The communication device is in a communications network that includes a network node, an anchor Transmission Reception Point (TRP), and an UL-only node. The method includes determining to target the UL-only node with a PRACH transmission. The method further includes determining a spatial filter for the PRACH transmission. The method further includes transmitting the PRACH transmission using the spatial filter.

[0033] According to other embodiments, a communication device, a computer program, a computer program product, a host, a system, or a non-transitory computer-readable medium is provided to perform one of the above methods.

[0034] In an embodiment, an advantage of the techniques proposed herein is that the wireless communication device can determine a spatial filter for PRACH transmission in deployments with UL-only nodes and be able to spatially direct the PRACH transmissions to or away from the UL-only nodes in order to facilitates distinguishing the PRACH transmissions.

[0035] Another advantage is that in some embodiments, the UE is allowed to determine a spatial filter for PRACH transmission in deployments with UL-only nodes, which can increase the chance that the UL-only node will receive a PRACH from the UE and hence that the UL- only node can be used for UL reception with the UE, which subsequently can improve UL user throughput and / or UL coverage in deployments with UL-only nodes.BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0037] Figure 1 is an exemplary depiction of time alignments of uplink transmissions according to one or more embodiments of the disclosure;

[0038] Figure 2 is an exemplary depiction of a Synchronization Signal Block (SSB) to Physical Random Access Channel (PRACH) preamble mapping according to one or more embodiments of the disclosure;

[0039] Figure 3 is another example of SSB to PRACH preamble mapping according to one or more embodiments of the disclosure;

[0040] Figure 4 is an example of a multiple transmission / reception point (TRP) deployment with an uplink only network node according to one or more embodiments of the disclosure;

[0041] Figure 5 is a flowchart of a method for determining a spatial filter for a PRACH transmission according to one or more embodiments of the disclosure;

[0042] Figure 6 is a flow chart illustrating an example of operations performed by a UE in accordance with some embodiments;

[0043] Figure 7 is a schematic diagram illustrating an example of TDMed and FDMed PRACH occasions configured to the UE in accordance with some embodiments;

[0044] Figure 8 is a schematic diagram illustrating an example of a mapping between PRACH occasions and UE antennas in accordance with some embodiments;

[0045] Figure 9 is a schematic diagram illustrating an example of a mapping between PRACH occasions targeting an UL-only node and SSBs from an anchor node in accordance with some embodiments;

[0046] Figure 10 is a flow chart illustrating an example of operations performed by a communication device in accordance with some embodiments;

[0047] Figure 11 is a block diagram of a communication system in accordance with some embodiments;

[0048] Figure 12 is a block diagram of a user equipment in accordance with some embodiments;

[0049] Figure 13 is a block diagram of a network node in accordance with some embodiments;

[0050] Figure 14 is a block diagram of a host, which may be an embodiment of the host of Figure 11, in accordance with some embodiments; and

[0051] Figure 15 is a block diagram of a virtualization environment in accordance with some embodiments.DETAILED DESCRIPTION

[0052] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications ofthese concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0053] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0054] There currently exist certain challenge(s).

[0055] In legacy New Radio (NR) specification, what spatial filter should be used for a PRACH transmission is not explicitly specified in Third Generation Partnership Project (3GPP) specifications. The common understanding is that for initial Contention Based Random Access (CBRA) based Physical Random Access Channel (PRACH) transmission in a PRACH resource associated to a Synchronization Signal Block (SSB), a User Equipment (UE) would use a spatial domain filter with which the SSB was received prior to the PRACH transmission. For PRACH triggered by Physical Downlink Control Channel (PDCCH) order, a SSB index and cell index (i.e., physical cell ID, PCI) are indicated in the PDCCH order. The UE can use the SSB index and cell index to determine in which direction the UE should transmit the PRACH.

[0056] For two timing advances (TAs) introduced in Rel-18 for multi- Downlink Control Information (DCI) based multi-Transmission Reception Point (TRP) transmission, two Timing Advance Groups (TAGs) are configured for a serving cell and each TAG is associated to one of two TRPs. Some SSBs are transmitted from one TRP and other SSBs are transmitted from the other TRP. For PRACH triggered by PDCCH order, a SSB index and cell index (i.e., physical cell ID, PCI) are indicated in the PDCCH order. The UE can use the SSB index and cell index to determine in which direction the UE should transmit the PRACH.

[0057] In addition, for two TAs introduced in Rel-18, if a first TRP triggers a PRACH transmission using a PDCCH order towards a second TRP, the PDCCH order would contain a SSB index associated to the second TRP. The UE can use the SSB index to determine a spatial filter for transmitting the PRACH and a PRACH transmit power.

[0058] For an uplink (UL)-only node, however, no SSBs are transmitted from the node, and it is therefore not possible for the UE to utilize a received SSB to determine in which direction it should transmit a PRACH towards the UL-only node. Hence, how to determine spatial filter for PDCCH order triggered PRACH transmission to UL-only nodes is an open issue.

[0059] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. The present disclosure describes several different methods on network assisting the UE to determine spatial filter for PRACH transmission in UL-only node deployments e.g., based on a previous SRS transmission.

[0060] A method is provided for determining a spatial filter to use for a PRACH in an uplink (UL) only network node deployment. The method can include receiving a higher layer message with a PRACH configuration, and then receiving a spatial filter indication associated with the PRACH configuration. Based on the spatial filter indication, the wireless communication device can determine one or more spatial filters to use to transmit the PRACH transmission. The spatial filter could be a Sounding Reference Signal (SRS) port or SRS resource. The spatial filter could also be an indication of an SRS Resource Indication (SRI) that indicates the wireless communication device transmits the PRACH in the same spatial filter as used when transmitting the SRS indicated in the SRI. In another embodiment, the spatial filter indication could indicate that the wireless communication device transmits the PRACH in the same spatial filter as used when last transmitting an SRS on an SRS resource, where the SRS resource is used as a spatial relation for an applied UL transmission configuration indicator (TCI) state.

[0061] Some of the embodiments included include:A method in a wireless device for determining a spatial filter for PRACH transmission triggered by a PDCCH order, the method comprising: a. Receive a higher layer message with a PRACH configuration; b. Receive a spatial filter indication associated with the PRACH configuration; c. Based on the spatial filter indication, determine one or more spatial filters to transmit the PRACH with.

[0062] In another embodiment, the spatial filter indication indicates an SRI, and where the UE should transmit the PRACH in the same spatial filter as was used when transmitting the SRS resource indicated by the SRI.

[0063] In another embodiment the spatial filter indication indicates an SRS, where the indication of the SRS can be a specific SRS port of a specific SRS resource (could be useful for example if the feature is associated with SRS with usage antenna Switching, where multiple SRS ports can be included in the same SRS resource, and where the different SRS ports belonging to the same SRS resource can be transmitted in different UE antennas / UE panels / spatial filters).

[0064] In another embodiment, the spatial filter indication indicates that the UE should transmit the PRACH in the same spatial filter as was used when last transmitting a first SRS resource, where the first SRS resource is used a spatial relation for an applied UL TCI state.

[0065] In the following, it is assumed that the UE is configured with separate DL and UL TCI states, and where at least one UL TCI state is associated with the UL-only node. It is further assumed that the UL TCI state associated with the UL-only node has an SRS (or other UL-RS) as source reference signal indicating the spatial QCL / spatial relation towards the UL-only node.

[0066] Although the term UL-only node is used, the embodiments disclosed below are nonlimiting and these embodiments are equally applicable to an anchor DL / UL and UL-only TRPs.

[0067] Certain embodiments may provide one or more of the following technical advantage(s). The present disclosure will help the UE determine a spatial filter for PRACH transmission in deployments with UL-only nodes. The techniques disclosed herein will also increase the chance that the UL-only node will receive a PRACH from the UE and hence that the UL-only node can be used for UL reception with the UE, which subsequently will improve UL user throughput and / or UL coverage in deployments with UL-only nodes.

[0068] In the following, it is assumed that the UE is configured with separate DL and UL TCI states, and where one UL TCI state is associated with the UL-only node. It is further assumed that the UL TCI state associated with the UL-only node has an SRS (or other UL-RS) as source reference signal indicating the spatial QCL / spatial relation towards the UL-only node.

[0069] Although we use the term UL-only node, the embodiments disclosed below are nonlimiting and these embodiments are equally applicable to UL-only TRPs.

[0070] Figure 4 illustrates a system where the invention could be useful, i.e., a mmWave UE is located in a multi-TRP deployment. As can be seen, different UE panels are associated with different TRPs, the anchor DL / UL TRP provides both DL and UL service, whilst the UL-only TRP can only provide UL service. It is also shown in the figure that, since the UE is far from the anchor DL / UL TRP compared to the UL-only TRP, the propagation distance to the anchor DL / UL TRP (TP_0) is larger than the propagation distance to the UL-only TRP (TP_1).

[0071] Figure 4 is an example of a multiple transmission / reception point (TRP) deployment with an uplink only network node according to one or more embodiments of the disclosure.

[0072] In Figure 4, an example illustrating a UE (or wireless communication device) 404 is connected to two TRPs (e.g., 406 and 402) of the gNB / base station / network node 408, where the first anchor TRP 402 provides both DL and UL service, while the second TRP is an UL-only network node 406 only provides UL service. In an embodiment, the UE 404 does not connect directly to the network node 408, but instead connects to the network node 408 via one or more of anchor TRPs 402 or 406. In various embodiments herein, when reference is made to the UE 404 providing or receiving information from the network node 408, it is to be appreciated that the information is provided or received via one or more of anchor TRPs 402 or 406. In legacy PRACH transmission towards a TRP, a spatial filter is determined based on a downlink signal such as a SSB transmitted from the TRP. For PRACH transmission towards an UL-only TRP, there is no downlink signal transmitted from the TRP. In one (general) embodiment, a PRACH transmission is associated with a previously transmitted UL reference signal such as SRS, wherethe UE should apply the same spatial filter for transmitting the PRACH as the one used for transmitting the associated SRS. In one detailed embodiment, a PRACH transmission towards the UL-only node is associated with a previously transmitted SRS towards the UL-only node. In one example, the transmission towards an anchor DL / UL node or an UL-only node is transparent to UE, only known to the network. In another example, the UE is made aware of whether a transmission is towards an anchor DL / UL node or an UL-only node.

[0073] Figure 5 is a flowchart of a method for determining a spatial filter for a PRACH transmission according to one or more embodiments of the disclosure.

[0074] In the method shown in Figure 5, the method can optionally begin at 502, where the UE 404 can provide to a network node (e.g., the gNB 408), capability information for supporting PRACH transmission to UL-only network nodes. The capability information can include information relating to: i) capability of indicating a spatial filter for the PRACH transmission using SRI in a Physical Downlink Control Channel configuration; ii) capability of indicating a spatial filter for the PRACH transmission using RRC signaling; and iii) capability of indicating a spatial filter for the PRACH transmission using MAC-CE signaling

[0075] At 504, the method can include receiving a message comprising a PRACH configuration, wherein the message is associated with a layer higher than a physical layer.

[0076] At 506, the method can include receiving a spatial filter indication associated with the PRACH configuration.

[0077] In an embodiment, the spatial filter indication indicates a Sounding Reference Signal, SRS, Resource Indication, SRI, that indicates that the one or more spatial filters match one or more spatial filters used when transmitting an SRS on an SRS resource associated with the SRI.

[0078] In an embodiment, the spatial filter indication indicates an SRS, wherein the indication of the SRS is an SRS port of an SRS resource.

[0079] In an embodiment, the spatial filter indication indicates that the one or more spatial filters match one or more spatial filters used when transmitting an SRS on an SRS resource, wherein the SRS resource is associated with a spatial relation for an applied UL TCI state.

[0080] In an embodiment, the UL TCI state is associated with an UL-only network node.

[0081] In an embodiment, the PRACH transmission is associated with a previously transmitted SRS transmission.

[0082] In an embodiment, the wireless communication device is aware the PRACH transmission is to an UL-only network node.

[0083] In an embodiment, the wireless communication device is unaware that the PRACH transmission is to an UL-only network node.

[0084] In an embodiment, the spatial filter indication associated with the PRACH configuration is received via a Radio Resource Control (RRC) configuration.

[0085] In an embodiment, the spatial filter indication associated with the PRACH configuration is received via a Medium Access Control (MAC) Control Element (CE) configuration.

[0086] In an embodiment, the spatial filter indication associated with the PRACH configuration is received via downlink control information (DCI).

[0087] In an embodiment, the PRACH transmission is triggered by the DCI, and an associated SRS resource index is indicated in a dedicated DCI field.

[0088] At 508, the method can include determining, based on the spatial filter indication, one or more spatial filters for a PRACH transmission.

[0089] At 510, the method can include transmitting the PRACH transmission using the one or more spatial filters.

[0090] In one embodiment, the association information between the PRACH transmission and SRS transmission is explicitly signaled to the UE. Alternatively, the association information between the PRACH transmission and SRS transmission can be implicitly provided to the UE, for example by pre-defined specification.

[0091] In one embodiment, the associated SRS used to determine spatial filter for a PRACH is indicated using RRC configuration. In one related embodiment, the associated SRS is indicated in a RACH configuration (e.g., one of RACH-ConfigCommon, RACH- ConfigDedicated, or similar RACH configuration).

[0092] In one embodiment, the associated SRS used to determine spatial filter for a PRACH is indicated using MAC-CE signaling, or DCI signaling etc.

[0093] In one embodiment, when the PRACH transmission is triggered by a PDCCH order (via a DCI), the PDCCH order can indicate the associated SRS resource index in a dedicated DCI field. In a related embodiment, a dedicated PDCCH order is configured for PRACH transmission towards an UL-only node with a dedicated PRACH configuration related to e.g., spatial filter, timing advance, transmission power level, etc. For example, there is an association between a spatial filter and a transmission power. In another related embodiment, the PDCCH order is configured with a general use case field and some use case specific fields. In this case,the network can indicate the use case (e.g., UL-only node) in the use case field and provide use case specific configuration in the use case specific field. In another embodiment, based on the use case indication in the use case field, some common (legacy, or reserved) fields in PDCCH order can have use case specific interpretation. For example, when the network indicates the use case for “UL-only node”, SS / PBCH index field may still indicate the time and frequency resource to perform PRACH transmission but using the UL spatial filter as described in this disclosure.

[0094] In one embodiment, the SRS is indicated by an SRS resource indication (SRI), and / or an SRS port index.

[0095] In one embodiment, the SRS is at least partly indicated by an SRS resource set indicator.

[0096] In one embodiment, the SRS is indicated by a new index, where the new index is indicating one SRS ports from one or more SRS resources in one or more SRS resource sets.

[0097] In one embodiment, the SRS is indicated by an UL-TCI state, and the associated SRS is the SRS resource used as source reference signal for that UL-TCI state. In this embodiment, the spatial filter for PRACH transmission is determined as the spatial filter used to transmit the SRS resource that is used as the source reference signal in the UL-TCI state. The steps involved in this embodiment can be summarized as follows:• an UL-TCI state X having SRS resource X as the source reference signal is activated to the UE via a MAC CE or a combination of MAC CE and DO. Note that the UE knows the spatial filter with which the SRS was most recently transmitted in SRS resource X.• A bit in the PDCCH order is introduced such that when that bit is set a first value (e.g., set to enable or a value of 1) when PRACH is triggered via PDCCH order, the UE will use the spatial filter with which the SRS was most recently transmitted in SRS resource X as the spatial filter for transmitting PRACH. When the bit is set to a second value (e.g., set to disable or a value of 0) when PRACH is triggered via PDCCH order, the UE will use the spatial filter with which SSB indicated in the PDCCH order was transmitted as the spatial filter for transmitting PRACH.

[0098] Note that after another UL-TCI state Y having SRS resource Y as the source reference signal is activated, when the bit in the PDCCH order is set to a first value when PRACH is triggered via PDCCH order, the UE will use the spatial filter with which SRS was most recently transmitted in SRS resource Y as the spatial filter for transmitting PRACH.

[0099] In one embodiment, the SRS is indicated by a TAG ID, and the associated SRS is the SRS resource used as source reference signal for the UL-TCI state associated with that TAG ID.In another embodiment, a bit in the PDCCH order is introduced such that when that bit is set to a first value (e.g., set to enable or a value of 1) when PRACH is triggered via PDCCH order, the SSB index indicated in the PDCCH order is reinterpreted as an SRS resource indicator (SRI) field.

[0100] That is, when the bit in the PDCCH order is set, a codepoint in the SSB index field will indicate an SRI, and the UE will use the spatial filter with which the SRS corresponding to the indicated SRI was most recently transmitted as the spatial filter for transmitting PRACH.

[0101] When the bit in the PDCCH order is not set, SSB index field will indicate an SSB index as originally intended, and the UE will use the spatial filter with which SSB indicated in the PDCCH order was transmitted as the spatial filter for transmitting PRACH.

[0102] In one embodiment, when an applied UL TCI state is using an SRS as source reference signal for spatial QCL / spatial relation and where the UL TCI state is associated with a TAG ID, the UE should determine the spatial filter for the associated PRACH transmission based on the spatial filter used for the last SRS transmission occasion.

[0103] In order to assist the gNB to determine the proper UE panel and UE spatial filter, it could be useful to associate the RACH occasions with UE UL spatial filters. In one embodiment, the UE may receive higher layer configured information about dedicated PRACH configuration towards UL-only nodes.

[0104] In one embodiment, the RACH-ConfigCommon (or other RACH related configuration IE) may include parameters describing a mapping between RACH occasions and spatial filters associated to UL-RS resources (e.g., via SRS resource indicator etc.). In one example, multiple UE spatial filters associated to UL RS resource (e.g., SRS resource indicators) can simultaneously send PRACH within a same RACH occasion. In another example, one spatial filter associated to a certain SRS resource indicator (SRI) may perform PRACH transmission in multiple RACH occasions.

[0105] In an alternative embodiment, if the UE is configured with SSB-index as referenceSignal in SRS-SpatialRelationinfo for each UL-RS resource (SRS), the UE can select the RACH occasions and the associated UL spatial filter based on the mapping between SSB- index and RACH occasions. The gNB can evaluate the qualified UL RS (UE UL spatial filter) based on the mapping between RACH occasions and SSBs, and the spatial relation between UL- RSs and SSBs.

[0106] In one embodiment, a new UE capability signaling is introduced where the UE indicates support for PRACH transmission towards UL-only nodes. The UE capability signaling include one or more of the following information:• Support of indicating spatial filter for PRACH transmission using SRI in PDCCH order• Support of indicating spatial filter for PRACH using RRC signaling• Support of indicating spatial filter for PRACH using MAC-CE signaling

[0107] FIG. 6 illustrates an example of operations performed by a UE.

[0108] At block 610, the UE can detect it is configured to communicate with an UL-only node. In some embodiments, the UE detects the configuration targeting an UL-only node based on explicit signaling from the network (conveyed through the anchor node using e.g., RRC, or MAC CE, or DCI, etc.). In additional or alternative embodiments, the UE detects the configuration targeting an UL-only node based on implicit information.

[0109] In additional or alternative embodiments, the UE receives configuration of an RRC field in legacy RRC IE(s) that indicates UL-only node operation, i.e., explicit indication using a dedicated RRC parameter used to indicate UL-only node operation.

[0110] In additional or alternative embodiments, the UE receives a new RRC configuration / IE (either explicit RRC configuration with a flag indicating UL-only node configuration or implicit RRC configuration, e.g., the UE might be configured with specific PRACH or TA targeting UL-only node operation) might be introduced in the specification indicating to the UE that is configured with UL-only nodes.

[0111] In additional or alternative embodiments, the UE is instructed by the network, or a specification, to re-interpret the legacy PRACH configurations in the UL-only operation. In additional or alternative embodiments, the UE is provided with new dedicated PRACH configurations targeting UL-only nodes.

[0112] In additional or alternative embodiments, the UE may receive PRACH configurations which enable simultaneous multiple PRACH transmissions. It is generally assumed that the UE will be provided with higher layer configured time and frequency domain PRACH configurations. Especially in FR2, the UE is typically equipped with multiple UE panels and should transmit the PRACH preamble in multiple different UE panels and / or UE beams, to make sure that the UL-only node can receive the PRACH. Hence, for a UE which is capable of simultaneous transmission from multiple UE panels / antennas, it will be useful to perform multiple PRACH transmissions at the same time. FIG. 7 depicts an example in which the PRACH transmissions can be multiplexed in time domain division and / or frequency domain division, e.g., the PRACH occasion 1 and PRACH occasion 3 are frequency division multiplexed (FDMed), whist the PRACH occasion 1 and PRACH occasion 2 are time division multiplexed (TDMed).

[0113] Returning to FIG. 6, at block 620, the UE detects a triggered PRACH transmission targeting an UL-only node. In some embodiments, the PRACH transmission is triggered by the network; alternatively, the PRACH transmission is triggered by the UE. In additional or alternative embodiments, the triggered PRACH transmission is a first PRACH transmission targeting the UL-only node; alternatively, the triggered PRACH transmission is a subsequent PRACH transmission targeting the UL-only node. In additional or alternative embodiments, the UE may apply different methods in the determination of the UL spatial filter depending on if the triggered PRACH is a first or subsequent PRACH transmission(s). It is generally assumed that PRACH will be the first UL transmission from the UE to the UL-only node, and before the first PRACH transmission, the UE does not have any information about the direction of the UL-only node. Meanwhile, for the subsequent PRACH transmissions, the UE may have some prior information about the direction of the UL-only node based on the response from the network on the first PRACH transmissions.

[0114] In additional or alternative embodiments, the determination that a triggered PRACH transmission is for an UL-only node is based on one or more of the assumptions. In some examples, the assumptions include that the triggered PRACH is a PRACH targeting UL-only nodes operation.

[0115] In additional or alternative examples, the assumptions include that the current applied UL-TCI state has an UL reference signal as spatial QCL source (e.g., an SRS).

[0116] In additional or alternative examples, the assumptions include that the configuration of an RRC field in legacy RRC IE(s) indicates UL-only node operation. Explicit indication can be provided using a dedicated RRC parameter to indicate UL-only node operation. Implicit indication can be provided via, for example, a Timing Advance (TA) or Power Control configurations specific targeting UL-only nodes.

[0117] In additional or alternative examples, the assumptions include that the new RRC configuration / IE (either explicit RRC configuration with a flag indicating UL-only node configuration or implicit RRC configuration, e.g., the UE might be configuration with specific PRACH or TA targeting UL-only node operation) might be introduced in the specification indicating to the UE that is configured with UL-only nodes.

[0118] In additional or alternative examples, the assumptions include that the indication in the PDCCH order (conveyed in a DCI) which triggers PRACH transmission. Explicit indication / flag can be provided indicating PRACH transmission targeting UL-only nodes. Implicit indication can be provided, for example, by triggering multiple PRACH transmissions in a single PDCCH order.

[0119] At block 630, the UE determines the UL spatial filter for PRACH transmission. In some embodiments, the UE may apply a fixed mapping between the UE panels / antennas and the configured PRACH occasions. In some examples, the spatial filter for PRACH transmission is based on the maximum number (M) of simultaneous PRACH transmissions supported by the UE, as well as the maximum number (N) of the UE panels / antennas. FIG. 8 illustrates an example which shows a mapping between PRACH occasions and UE TX / RX chains. In this example, the UE, equipped with 4 antennas, is capable of simultaneously transmitting two PRACH signals. The four spatial filters are mapped to four PRACH occasions, accordingly. In additional or alternative embodiments, the UE can map beams from a different antenna panel to the same FDMed PRACH occasion group, i.e., to sweep beams from a different UE panel at the same time. In FIG. 8, the UE TX / RX chains TX0-RX0 and TX0-RX1 can be associated to the same UE panel, whilst the UE TX / RX chains TX1-RX0 and TX1-RX1 can be associated to the same UE panel.

[0120] In additional or alternative embodiments, the same UE beam / antenna can be mapped to multiple PRACH occasions in one PRACH period. In another embodiment, one UE beam / antenna can be applied to a PRACH occasion once over K PRACH periods.

[0121] To allow dynamic update of UL spatial filter for a certain PRACH occasion is efficient for subsequent PRACH transmissions for which the UE might have some prior information about the direction of the UL-only node. In some embodiments, the dynamic update of the spatial filter for PRACH transmission may depend on for example one or more of the following factors: A previous UL transmission of UL RS, and / or UL channels (e.g., PU{C,S}CH); A previous indication of UL TCI State; or Sequentially sweeping through different spatial filter to attain spatial diversity for the PRACH transmission.

[0122] In additional or alternative embodiments, the spatial filter for PRACH transmission is associated to a previously transmitted UL signal, e.g., PUCCH / PUSCH etc. towards the UL-only node. For example, the UE might be indicated with a PUSCH precoder (using e.g. TPMI or SRI) pointing in a certain spatial direction to be used in a previous PUSCH transmission, and the UE might then use a similar precoder when transmitting the PRACH as was made when transmitting the indicated PUSCH precoder previously.

[0123] In additional or alternative embodiments, the spatial filter is determined by a current applied UL-TCI state. For example, the UE can transmit the PRACH using the same spatial filter that is used when transmitting an UL reference signal or UL channel associated with the applied UL TCI state.

[0124] In additional or alternative embodiments, the UE uses the same spatial filter for the PRACH transmission as was used for the SRS resource used as source reference signal for the applied UL-TCI state.

[0125] In additional or alternative embodiments, the spatial filter is determined by sequentially sweeping through different UE antennas / UE panels / spatial directions. In one embodiment, different parts of a PRACH occasion are transmitted in different UE antennas / UE panels / spatial directions. In additional or alternative embodiments, the UE switches UE antenna / UE panel / spatial direction for every PRACH re-transmission.

[0126] In additional or alternative embodiments, the UE may dynamically change the spatial filter according to the reception status of RACH response (RAR) associated to previous transmitted PRACH. In additional or alternative embodiments, if the said RAR is not received, the UE should select one or multiple UL spatial filters which are different from those were used in the previous PRACH transmissions when transmitting the new PRACH to the UL-only node.

[0127] In additional or alternative embodiments, the UE may determine the spatial filter for PRACH transmission based on SSBs or other DL RSs from an anchor (DL / UL) node. This could be a valid scenario when the UE transmits subsequent PRACH when the UL-only node is close to the anchor DL / UL nodes that the link to UL-only node has similar propagation conditions as the links towards the anchor DL / UL nodes. The UE may acquire this information from the RACH response from the network associated to the first PRACH transmissions. In additional or alternative embodiments, the UE may select the PRACH occasions, and the associated UL spatial filters based on a mapping between the PRACH occasions and the SSB indices of the anchor node which provides the DL control signaling e.g., MAC CE, or DCI, etc. FIG. 9 illustrates an example of the mapping between the UE UL spatial filters, PRACH occasions targeting an UL-only node and SSB indices from the anchor node. In FIG. 9, the UE is equipped with 3 antennas and only one TX chain. The three PRACH occasions in one PRACH period are mapped to three SSB indices associated to the anchor node. In some examples, the UE may select the PRACH occasion and the associated spatial UL filter upon receiving an indicated SSBs or DL RSs from the anchor node. In another example, the UE may select the PRACH occasion, and the associated spatial UL filter based on the qualities (e.g., RSRP or RSRQ etc.) of the measured SSBs or DL RSs from the anchor node. In additional or alternative examples, the spatial UL filter can be based on the measured DL RSs from multiple anchor nodes. For example, the UE can select the UL spatial filter for PRACH transmission if the measurement of the corresponding DL RSs from multiple anchor nodes is better than a threshold value.

[0128] In additional or alternative embodiments, the spatial filter of the PRACH transmission is associated to a previous transmitted UL reference signal such as SRS, where the UE could apply the same spatial filter for transmitting the PRACH as the one used for transmitting the latest SRS towards the UL-only node. In additional or alternative embodiments, the spatial filter of the PRACH transmission is the one used for transmitting the latest SRS, if the transmission towards an anchor DL / UL or an UL-only node is transparent to the UE. This procedure can be suitable for subsequent PRACH transmission for which the UE has already some initial information about the direction of the UL-only node based on the response from the network about the first PRACH transmissions.

[0129] Returning to FIG. 6, at block 640, the UE transmits towards the UL-only node using the UL spatial filter determined at block 630.

[0130] Operations of the communication device 1200 (implemented using the structure of Figure 12) will now be discussed with reference to the flow chart of FIG. 10 according to some embodiments of inventive concepts. For example, modules may be stored in memory 1210 of Figure 12, and these modules may provide instructions so that when the instructions of a module are executed by respective communication device processing circuitry 1202, communication device 1200 performs respective operations of the flow chart.

[0131] FIG. 10 illustrates an example of operations performed by a communication device in a communications network that includes a network node and an UL-only node.

[0132] At block 1010, processing circuitry 1202 receives, via communication interface 1212, a message from the network node including configuration information for PRACH transmissions transmitted by the communication device. In some embodiments, the configuration information includes at least one of: an indication of a time division multiplexed, TDMed, PRACH transmission configuration; and an indication of a frequency division multiplexed, FDMed, PRACH transmission configuration.

[0133] At block 1020, processing circuitry 1202 determines to transmit a PRACH transmission. In some embodiments, the PRACH transmission includes a network-triggered PRACH transmission. Determining to transmit the PRACH transmission includes receiving a physical downlink control channel, PDCCH, order from the network node indicating that the communication device initialized a random access channel, RACH, procedure.

[0134] In additional or alternative embodiments, the PRACH transmission includes a devicetriggered PRACH transmission. Determining to transmit the PRACH transmission includes at least one of: determining a time alignment timer has expired; and determining an UL timing clock has expired.

[0135] At block 1030, processing circuitry 1202 determines to target the UL-only node with the PRACH transmission. In some embodiments, determining to target the UL-only node with the PRACH transmission includes determining to target the UL-only node with the PRACH transmission based on a PDCCH order (that requests the PRACH transmission).

[0136] In additional or alternative embodiments, determining to target the UL-only node with the PRACH transmission includes determining to target the UL-only node with the PRACH transmission based on at least one of: the PRACH is a PRACH targeting UL-only node operation; a current applied UL-transmission configuration indication, TCI, has an UL reference signal as a spatial quasi co location, QCL, source; configuration of a radio resource control, RRC, field in a RRC information element, IE, that indicates UL-only node operation; and an indication in a RRC signal.

[0137] At block 1040, processing circuitry 1202 determines a spatial filter for the PRACH transmission. In some embodiments, determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on at least one of: a number of transmitter, TX, chains in the communication device; a number of receiver, RX, chains in the communication device; a maximum number of simultaneous TX chains in the communication device; a number of panels in the communication device; and a number of antennas per panel in the communication device.

[0138] In additional or alternative embodiments, determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on a fixed mapping between PRACH time and / or frequency domain occasions and antennas and / or panels of the communication device.

[0139] In additional or alternative embodiments, the spatial filter is a second filter. Determining the second spatial filter for the PRACH transmission includes determining the second spatial filter for the PRACH transmission based on a first spatial filter that was previously used to transmit an UL reference signal, RS.

[0140] In additional or alternative embodiments, determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on at least one of: an UL transmission configuration indication; and a sounding reference signal resource indicator, SRI, associated with an UL transmission.

[0141] In additional or alternative embodiments, the spatial filter is a second filter. Determining the second spatial filter for the PRACH transmission includes determining the second spatial filter for the PRACH transmission based on first spatial filter used in a physical uplink control channel, PUCCH, transmission, a physical uplink shared channel, PUSCH,transmission, an UL transmission configuration indication, TCI, state, or a sounding reference signal resource indicator, SRI, associated with an UL transmission.

[0142] In additional or alternative embodiments, the spatial filter is a second filter. The PRACH transmission is a second PRACH transmission. Determining the second spatial filter for the second PRACH transmission includes determining the second spatial filter for the second PRACH transmission based on a first spatial filter previously being used to transmit a first PRACH transmission.

[0143] In additional or alternative embodiments, the spatial filter is a second filter and the PRACH transmission is a second PRACH transmission. Determining the second spatial filter for the second PRACH transmission includes determining the second spatial filter for the second PRACH transmission based on a first spatial filter previously not being used to transmit a first PRACH transmission.

[0144] In additional or alternative embodiments, determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on an indication of a synchronization signal block, SSB, or downlink, DL, reference signal, RS, received from the network node.

[0145] In additional or alternative embodiments, determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on a measured quality of a synchronization signal block, SSB, or downlink, DL, reference signal, RS transmitted by the network node.

[0146] In additional or alternative embodiments, the PRACH transmission is a second PRACH transmission. Determining the spatial filter for the PRACH transmission includes determining the spatial filter for the PRACH transmission based on a RACH response associated to a first PRACH transmission that was previously transmitted by the communication device.

[0147] At block 1050, processing circuitry 1202 transmits, via communication interface 1212, the PRACH transmission using the spatial filter. In some embodiments, transmitting the PRACH transmission includes transmitting a first PRACH transmission targeting the UL-only node. In additional or alternative embodiments, transmitting the PRACH transmission includes transmitting a second PRACH transmission targeting the UL-only node subsequent to a first PRACH transmission targeting the UL-only node having been transmitted.

[0148] Various operations from the flow chart of FIG. 10 may be optional with respect to some embodiments of communication devices and related methods.

[0149] Figure 11 shows an example of a communication system 1100 in accordance with some embodiments.

[0150] In the example, the communication system 1100 includes a telecommunication network 1102 that includes an access network 1104, such as a radio access network (RAN), and a core network 1106, which includes one or more core network nodes 1108. The access network 1104 includes one or more access network nodes, such as network nodes 1110a and 1110b (one or more of which may be generally referred to as network nodes 1110), or any other similar 3rd Generation Partnership Project (3GPP) access node or non-3GPP access point. Moreover, as will be appreciated by those of skill in the art, the network nodes 1110 are not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that the network nodes 1110 may include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 1102 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 1102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 1102, including one or more network nodes 1110 and / or core network nodes 1108.

[0151] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time RAN control application (e.g., xApp) or a non-real time RAN automation application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Intents and content-aware notifications described herein may be communicated from a 3GPP network node or an ORAN network node over 3GPP-defined interfaces (e.g., N2, N3) and / or ORAN Alliance-defined interfaces (e.g., Al, 01). Moreover, an ORAN network node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance. The network nodes 1110 facilitate direct or indirect connection of user equipment (UE), such as by connecting wireless devices 1112a, 1112b, 1112c, and 1112d(one or more of which may be generally referred to as UEs 1112) to the core network 1106 over one or more wireless connections. The network nodes 1110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 1112a, 1112b, 1112c, and 1112d (one or more of which may be generally referred to as UEs 1112) to the core network 1106 over one or more wireless connections.

[0152] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 1100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 1100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0153] The UEs 1112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 1110 and other communication devices. Similarly, the network nodes 1110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 1112 and / or with other network nodes or equipment in the telecommunication network 1102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 1102.

[0154] In the depicted example, the core network 1106 connects the network nodes 1110 to one or more hosts, such as host 1116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 1106 includes one more core network nodes (e.g., core network node 1108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDE), Unified Data Management (UDM), Security EdgeProtection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0155] The host 1116 may be under the ownership or control of a service provider other than an operator or provider of the access network 1104 and / or the telecommunication network 1102 and may be operated by the service provider or on behalf of the service provider. The host 1116 may host a variety of applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0156] As a whole, the communication system 1100 of Figure 11 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Fong Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z- Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0157] In some examples, the telecommunication network 1102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 1102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 1102. For example, the telecommunications network 1102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0158] In some examples, the UEs 1112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 1104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1104. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. Forexample, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved- UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0159] In the example, the hub 1114 communicates with the access network 1104 to facilitate indirect communication between one or more UEs (e.g., UE 1112c and / or 1112d) and network nodes (e.g., network node 1110b). In some examples, the hub 1114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1114 may be a broadband router enabling access to the core network 1106 for the UEs. As another example, the hub 1114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1110, or by executable code, script, process, or other instructions in the hub 1114. As another example, the hub 1114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 1114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 1114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 1114 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0160] The hub 1114 may have a constant / persistent or intermittent connection to the network node 1110b. The hub 1114 may also allow for a different communication scheme and / or schedule between the hub 1114 and UEs (e.g., UE 1112c and / or 1112d), and between the hub 1114 and the core network 1106. In other examples, the hub 1114 is connected to the core network 1106 and / or one or more UEs via a wired connection. Moreover, the hub 1114 may be configured to connect to an M2M service provider over the access network 1104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1110 while still connected via the hub 1114 via a wired or wireless connection. In some embodiments, the hub 1114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 1110b. In other embodiments, the hub 1114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1110b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0161] Figure 12 shows a UE 1200 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0162] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0163] The UE 1200 includes processing circuitry 1202 that is operatively coupled via a bus 1204 to an input / output interface 1206, a power source 1208, a memory 1210, a communication interface 1212, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 12. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0164] The processing circuitry 1202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 1210. The processing circuitry 1202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computerprograms, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 1202 may include multiple central processing units (CPUs).

[0165] In the example, the input / output interface 1206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 1200. Examples of an input device include a touch- sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0166] In some embodiments, the power source 1208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 1208 may further include power circuitry for delivering power from the power source 1208 itself, and / or an external power source, to the various parts of the UE 1200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1208 to make the power suitable for the respective components of the UE 1200 to which power is supplied.

[0167] The memory 1210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable readonly memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1210 includes one or more application programs 1214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1216. The memory 1210 may store, for use by the UE 1200, any of a variety of various operating systems or combinations of operating systems.

[0168] The memory 1210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 1210 may allow the UE 1200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 1210, which may be or comprise a device-readable storage medium.

[0169] The processing circuitry 1202 may be configured to communicate with an access network or other network using the communication interface 1212. The communication interface 1212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1222. The communication interface 1212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1218 and / or a receiver 1220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1218 and receiver 1220 may be coupled to one or more antennas (e.g., antenna 1222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0170] In the illustrated embodiment, communication functions of the communication interface 1212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division MultipleAccess (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0171] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0172] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0173] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 1200 shown in Figure 12.

[0174] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0175] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0176] Figure 13 shows a network node 1300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs), NR NodeBs (gNBs)), O-RAN nodes, or components of an O-RAN node (e.g., intelligent controller, O-RU, O-DU, O-CU).

[0177] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0178] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllerssuch as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0179] The network node 1300 includes a processing circuitry 1302, a memory 1304, a communication interface 1306, and a power source 1308. The network node 1300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeB s. In such a scenario, each unique NodeB and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 1300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1304 for different RATs) and some components may be reused (e.g., a same antenna 1310 may be shared by different RATs). The network node 1300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1300.

[0180] The processing circuitry 1302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1300 components, such as the memory 1304, to provide network node 1300 functionality.

[0181] In some embodiments, the processing circuitry 1302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1302 includes one or more of radio frequency (RF) transceiver circuitry 1312 and baseband processing circuitry 1314. In some embodiments, the radio frequency (RF) transceiver circuitry 1312 and the baseband processing circuitry 1314 may be on separate chips (or sets of chips), boards, or units, such as radio unitsand digital units. In alternative embodiments, part or all of RF transceiver circuitry 1312 and baseband processing circuitry 1314 may be on the same chip or set of chips, boards, or units.

[0182] The memory 1304 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1302. The memory 1304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1302 and utilized by the network node 1300. The memory 1304 may be used to store any calculations made by the processing circuitry 1302 and / or any data received via the communication interface 1306. In some embodiments, the processing circuitry 1302 and memory 1304 are integrated.

[0183] The communication interface 1306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1306 comprises port(s) / terminal(s) 1316 to send and receive data, for example to and from a network over a wired connection. The communication interface 1306 also includes radio front-end circuitry 1318 that may be coupled to, or in certain embodiments a part of, the antenna 1310. Radio front-end circuitry 1318 comprises filters 1320 and amplifiers 1322. The radio front-end circuitry 1318 may be connected to an antenna 1310 and processing circuitry 1302. The radio front-end circuitry may be configured to condition signals communicated between antenna 1310 and processing circuitry 1302. The radio front-end circuitry 1318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1320 and / or amplifiers 1322. The radio signal may then be transmitted via the antenna 1310. Similarly, when receiving data, the antenna 1310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1318. The digital data may be passed to the processing circuitry 1302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0184] In certain alternative embodiments, the network node 1300 does not include separate radio front-end circuitry 1318, instead, the processing circuitry 1302 includes radio front-endcircuitry and is connected to the antenna 1310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1312 is part of the communication interface 1306. In still other embodiments, the communication interface 1306 includes one or more ports or terminals 1316, the radio front-end circuitry 1318, and the RF transceiver circuitry 1312, as part of a radio unit (not shown), and the communication interface 1306 communicates with the baseband processing circuitry 1314, which is part of a digital unit (not shown).

[0185] The antenna 1310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1310 may be coupled to the radio front-end circuitry 1318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1310 is separate from the network node 1300 and connectable to the network node 1300 through an interface or port.

[0186] The antenna 1310, communication interface 1306, and / or the processing circuitry 1302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1310, the communication interface 1306, and / or the processing circuitry 1302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0187] The power source 1308 provides power to the various components of network node 1300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1300 with power for performing the functionality described herein. For example, the network node 1300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1308. As a further example, the power source 1308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0188] Embodiments of the network node 1300 may include additional components beyond those shown in Figure 13 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1300 may include userinterface equipment to allow input of information into the network node 1300 and to allow output of information from the network node 1300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1300.

[0189] Figure 14 is a block diagram of a host 1400, which may be an embodiment of the host 1116 of Figure 11 , in accordance with various aspects described herein. As used herein, the host 1400 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1400 may provide one or more services to one or more UEs.

[0190] The host 1400 includes processing circuitry 1402 that is operatively coupled via a bus 1404 to an input / output interface 1406, a network interface 1408, a power source 1410, and a memory 1412. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 12 and 13, such that the descriptions thereof are generally applicable to the corresponding components of host 1400.

[0191] The memory 1412 may include one or more computer programs including one or more host application programs 1414 and data 1416, which may include user data, e.g., data generated by a UE for the host 1400 or data generated by the host 1400 for a UE. Embodiments of the host 1400 may utilize only a subset or all of the components shown. The host application programs 1414 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 1414 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1400 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1414 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0192] Figure 15 is a block diagram illustrating a virtualization environment 1500 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include31 virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1500 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1500 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface.

[0193] Applications 1502 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0194] Hardware 1504 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1506 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1508a and 1508b (one or more of which may be generally referred to as VMs 1508), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1506 may present a virtual operating platform that appears like networking hardware to the VMs 1508.

[0195] The VMs 1508 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1506. Different embodiments of the instance of a virtual appliance 1502 may be implemented on one or more of VMs 1508, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0196] In the context of NFV, a VM 1508 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1508, and that part of hardware 1504 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1508 on top of the hardware 1504 and corresponds to the application 1502.

[0197] Hardware 1504 may be implemented in a standalone network node with generic or specific components. Hardware 1504 may implement some functions via virtualization. Alternatively, hardware 1504 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1510, which, among others, oversees lifecycle management of applications 1502. In some embodiments, hardware 1504 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1512 which may alternatively be used for communication between hardware nodes and radio units.

[0198] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box or nested within multiple boxes, in practice computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of thecomponents may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0199] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hardwired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole and / or by end users and a wireless network generally.

Claims

CLAIMS1. A method implemented in a wireless communication device (404, 1200) for determining a spatial filter for a Physical Random Access Channel, PRACH, transmission, the method comprising: receiving (504) a message comprising a PRACH configuration; receiving (506) a spatial filter indication associated with the PRACH configuration; based on the spatial filter indication, determining (508) one or more spatial filters for a PRACH transmission; and transmitting (510) the PRACH transmission using the one or more spatial filters.

2. The method of claim 1, wherein the spatial filter indication indicates a Sounding Reference Signal, SRS, Resource Indication, SRI, that indicates that the one or more spatial filters match one or more spatial filters used when transmitting an SRS on an SRS resource associated with the SRI.

3. The method of claim 1, wherein the spatial filter indication indicates a Sounding Reference Signal, SRS, wherein the indication of the SRS is an SRS port of an SRS resource.

4. The method of claim 1 , wherein the spatial filter indication indicates that the one or more spatial filters match one or more spatial filters used when transmitting one or more Sounding Reference Signals, SRSs, on one or more SRS resources, wherein each of the one or more SRS resources is associated with a spatial relation for an applied uplink, UL, Transmission Configuration Indicator, TCI, state.

5. The method of claim 1, wherein the spatial filter indication indicates that the one or more spatial filters match one or more spatial filters used when transmitting a Sounding Reference Signal, SRS, on an SRS resource, wherein the SRS resource is the source reference signal for an uplink, UL, Transmission Configuration Indicator, TCI, state associated with a Timing Advance Group, TAG, identifier.

6. The method of claims 4 or 5, wherein the UL TCI state is associated with an UL-only network node (406).

7. The method of any of claims 1 to 6, wherein the PRACH transmission is associated with a previously transmitted SRS transmission.

8. The method of any of claims 1 to 7, wherein the wireless communication device (404, 1200) is aware the PRACH transmission is to an UL-only network node (406).

9. The method of any of claims 1 to 7, wherein the wireless communication device (404, 1200) is unaware the PRACH transmission is to an UL-only network node (406).

10. The method of any of claims 1 to 9, wherein the spatial filter indication associated with the PRACH configuration is received via a Radio Resource Control, RRC, configuration.

11. The method of any of claims 1 to 9, wherein the spatial filter indication associated with the PRACH configuration is received via a Medium Access Control, MAC, Control Element, CE, configuration.

12. The method of any of claims 1 to 9, wherein the spatial filter indication associated with the PRACH configuration is received via downlink control information, DCI.

13. The method of claim 12, wherein the PRACH transmission is triggered by the DCI, and an associated Synchronization Signal Block is indicated in a dedicated DCI field.

14. The method of claim 12, wherein the PRACH transmission is triggered by the DCI, and an associated SRS resource index is indicated in a dedicated DCI field.

15. The method of claim 14, wherein the PRACH transmission is triggered by the DCI and an associated TCI state is indicated in the dedicated DCI field.

16. The method of any of claims 1 to 15, further comprising: providing (502), to a network node (408), via an anchor Transmission Reception Point, TRP, (402), capability information for supporting the PRACH transmission to an UL-only network nodes (406).

17. The method of claim 16, wherein the capability information comprises one or more of:i) capability to support of indicating a spatial filter for the PRACH transmission using SRI in a Physical Downlink Control Channel configuration; ii) capability to support of indicating a spatial filter for the PRACH transmission using RRC signaling; and iii) capability to support indicating a spatial filter for the PRACH transmission using MAC-CE signaling.

18. A wireless communication device (404, 1200) configured to determine a spatial filter for a Physical Random Access Channel, PRACH, transmission, the wireless communication device (404) comprising a radio interface and processing circuitry configured to: receive (504) a message comprising a PRACH configuration; receive (506) a spatial filter indication associated with the PRACH configuration; based on the spatial filter indication, determine (508) one or more spatial filters for a PRACH transmission; and transmit (510) the PRACH transmission using the one or more spatial filters.

19. The wireless communication device (404, 1200) of claim 18, wherein the processing circuitry is further configured to perform any of the methods of claims 2 to 17.

20. A computer program (1214), comprising instructions which, when executed on at least one processor (1202), cause the at least one processor (1202) to carry out the method according to any one of claims 1 to 17.

21. A method of operating a wireless communication device (404, 1200) in a communications network that includes a network node (408), an anchor Transmission Reception Point, TRP (402), and an uplink, UL, only node (406), the method comprising: determining (1030) to target the UL-only node with a Physical Random Access Channel, PRACH, transmission; determining (1040) a spatial filter for the PRACH transmission; and transmitting (1050) the PRACH transmission using the spatial filter.

22. The method of claim 21, further comprising: receiving (1010), via the anchor TRP (402), a message from the network node (408) including configuration information for PRACH transmissions transmitted by the wirelesscommunication device (404, 1200).

23. The method of claim 22, wherein the configuration information includes at least one of: an indication of a time division multiplexed, TDMed, PRACH transmission configuration; and an indication of a frequency division multiplexed, FDMed, PRACH transmission configuration.

24. The method of any of claims 21 to 23, further comprising: determining (1020) to transmit the PRACH transmission.

25. The method of claim 24, wherein the PRACH transmission comprises a network-triggered PRACH transmission, and wherein determining to transmit the PRACH transmission comprises receiving, via the anchor TRP (402), a physical downlink control channel, PDCCH, order from the network node (408) indicating that the wireless communication device (404, 1200) initialize a random access channel, RACH, procedure.

26. The method of claim 25, wherein determining to target the UL-only node (406) with the PRACH transmission comprises determining to target the UL-only node (406) with the PRACH transmission based on the PDCCH order.

27. The method of claim 24, wherein the PRACH transmission comprises a device-triggered PRACH transmission, and wherein determining to transmit the PRACH transmission comprises at least one of: determining a time alignment timer has expired; and determining an UL timing clock has expired.

28. The method of any of claims 21 to 27, wherein determining to target the UL-only node (406) with the PRACH transmission comprises determining to target the UL-only node (406) with the PRACH transmission based on at least one of: the PRACH is a PRACH targeting UL-only node operation; a current applied UL-transmission configuration indication, TCI, has an UL reference signal as a spatial quasi co location, QCL, source;configuration of a radio resource control, RRC, field in a RRC information element, IE, that indicates UL-only node operation; and an indication in a RRC signal.

29. The method of any of claims 21 to 28, wherein transmitting the PRACH transmission comprises transmitting a first PRACH transmission targeting the UL-only node (406).

30. The method of any of claims 21 to 29, wherein transmitting the PRACH transmission comprises transmitting a second PRACH transmission targeting the UL-only node (406) subsequent to a first PRACH transmission targeting the UL-only node (406) having been transmitted.

31. The method of any of claims 21 to 30, wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission based on at least one of: a number of transmitter, TX, chains in the wireless communication device (404, 1200); a number of receiver, RX, chains in the wireless communication device (404, 1200); a maximum number of simultaneous TX chains in the wireless communication device (404, 1200); a number of panels in the wireless communication device (404, 1200); and a number of antennas per panel in the wireless communication device (404, 1200).

32. The method of any of claims 21 to 31, wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission based on a fixed mapping between PRACH time and / or frequency domain occasions and antennas and / or panels of the wireless communication device (404, 1200).

33. The method of any of claims 21 to 32, wherein the spatial filter is a second filter, and wherein determining the second spatial filter for the PRACH transmission comprises determining the second spatial filter for the PRACH transmission based on a first spatial filter that was previously used to transmit an UL reference signal, RS.

34. The method of any of claims 21 to 33, wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission basedon at least one of: an UL transmission configuration indication; and a sounding reference signal resource indicator, SRI, associated with an UL transmission.

35. The method of any of claims 21 to 34, wherein the spatial filter is a second filter, and wherein determining the second spatial filter for the PRACH transmission comprises determining the second spatial filter for the PRACH transmission based on first spatial filter used in a physical uplink control channel, PUCCH, transmission, a physical uplink shared channel, PUSCH, transmission, an UL transmission configuration indication, TCI, state, or a sounding reference signal resource indicator, SRI, associated with an UL transmission.

36. The method of any of claims 21 to 35, wherein the spatial filter is a second filter, wherein the PRACH transmission is a second PRACH transmission, and wherein determining the second spatial filter for the second PRACH transmission comprises determining the second spatial filter for the second PRACH transmission based on a first spatial filter previously being used to transmit a first PRACH transmission.

37. The method of any of claims 21 to 36, wherein the spatial filter is a second filter, wherein the PRACH transmission is a second PRACH transmission, and wherein determining the second spatial filter for the second PRACH transmission comprises determining the second spatial filter for the second PRACH transmission based on a first spatial filter previously not being used to transmit a first PRACH transmission.

38. The method of any of claims 21 to 37, wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission based on an indication of a synchronization signal block, SSB, or downlink, DL, reference signal, RS, received from the network node (408) via the anchor TRP (402).

39. The method of any of claims 21 to 38, wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission based on a measured quality of a synchronization signal block, SSB, or downlink, DL, reference signal, RS transmitted by the network node (408) via the anchor TRP (402).

40. The method of any of claims 21 to 39, wherein the PRACH transmission is a secondPRACH transmission, and wherein determining the spatial filter for the PRACH transmission comprises determining the spatial filter for the PRACH transmission based on a RACH response associated to a first PRACH transmission that was previously transmitted by the wireless communication device (404, 1200).

41. A wireless communication device (404, 1200), the wireless communication device (404, 1200) comprising a radio interface and processing circuitry configured to: determine (1030) to target the UL-only node with a Physical Random Access Channel, PRACH, transmission; determine (1040) a spatial filter for the PRACH transmission; and transmit (1050) the PRACH transmission using the spatial filter.

42. The wireless communication device (404, 1200) of claim 41, wherein the processing circuitry (1202) is further configured to perform any of the methods of claims 22 to 40.

43. A computer program (1214), comprising instructions which, when executed on at least one processor (1202), cause the at least one processor (1202) to carry out the method according to any one of claims 21 to 40.

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