Indication for contention free random access

Abstract

Methods, systems and apparatuses are disclosed. In an example method implemented in a user equipment (UE) configured to communicate with a network node, the method includes receiving control signaling from the network node, selecting between random access, RA, resource types for a contention-free RA procedure based on the received control signaling, and performing the contention-free RA procedure based on the selection.

Description

[0001] INDICATION FOR CONTENTION FREE RANDOM ACCESS

[0002] FIELD

[0003] The present disclosure relates to wireless communications, and in particular, to contention-free random access (RA).

[0004] BACKGROUND

[0005] The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile user equipments (UE), as well as communication between network nodes and between UEs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0006] FDD and TDD systems

[0007] Transmission and reception from a node, e.g. a terminal in a cellular system (e.g., a user equipment (UE)), can be multiplexed in the frequency domain or in the time domain (or combinations thereof). Frequency Division Duplex (FDD) as illustrated to the left in FIG. 1 (which depicts frequency- and time-division duplex) implies that downlink and uplink transmission take place in different, sufficiently separated, frequency bands. Time Division Duplex (TDD), as illustrated to the right in FIG. 1, implies that downlink and uplink transmission take place in different, non-overlapping time slots. Thus, TDD can operate in unpaired spectrum, whereas FDD requires paired spectrum.

[0008] Typically, the structure of the transmitted signal in a communication system may be organized in the form of a frame structure.

[0009] In more detail, the following two information elements (IES) are defined in current specifications, e.g., 3GPP specifications. The TDD pattern is typically configured with at least the first IE and optionally the 2nd IE:

[0010] • TDD-DL-UL-ConfigCommon (cell -specific)

[0011] • TDD-DL-UL-ConfigDedicated (UE-specific)

[0012] The first IE may be cell specific (common to all UEs) and may be provided by broadcast signaling. It provides the number of slots in the TDD pattern via a reference subcarrier spacing and a periodicity such that the S-slot pattern repeats every S slots. This IE may allow for very flexible configuration of the pattern characterized as follows: • A number of full downlink slots at the beginning of the pattern configured by the parameter nDownlinkSlots

[0013] • A number of full uplink slots at the end of the pattern configured by the parameter nUplinkSlots

[0014] • A number of downlink ('D') symbols following the full downlink slots configured by the parameter nDownlinkSymbols

[0015] • A number of uplink ('U') symbols preceding the full downlink slots configured by the parameter nUplinkSlots

[0016] • If there is a gap between the last downlink symbol and the first uplink symbol, then all symbols in the gap are characterized as flexible ('F'). A symbol classified as 'F' can be used for downlink or uplink. A UE determines the direction in one of the following two ways: o Detecting a DCI that schedules / triggers a DL signal / channel, e.g., PDSCH, CSI-RS or schedules / triggers an UL signal / channel, e.g., PUSCH, SRS, etc. o By dedicated (UE-specific) signaling of the IE TDD-DL-UL- ConfigDedicated. This parameter overrides some or all of the 'F' symbols in the pattern, thus providing a semi-static indication of whether a symbol is classified as 'D' or U'

[0017] • Optionally, a second pattern that is concatenated to the first pattern can be configured as above. If a second pattern is configured, the constraint is that the sum of the periodicities of the two patterns must evenly divide 20 ms.

[0018] FIG. 2 shows an example TDD DL / UL pattern configured by TDD-DL-UL- ConfigCommon. It consists of three full 'D' slots, one full U' slot, with a mixed slot in between consisting of four 'D' symbols and three ' symbols. The remaining seven symbols in the mixed slot are classified as 'F.' That is, the pattern includes S = 5 slots. TDD-DL-UL-ConfigCommon configures the cell-specific pattern, and TDD-DL-UL- ConfigDedicated (if provided) UE-specifically configures the direction for some or all of the 'F' symbols in the cell-specific pattern.

[0019] If a UE is not configured with TDD-DL-UL-ConfigDedicated, then the pattern at the top of the diagram in FIG. 2 is what may be assumed. As stated above, the network can make use of the 'F' symbols flexibly, by scheduling / triggering either an uplink or a downlink signal / channel in a UE specific manner. This allows for dynamic behavior: the direction is not known to the UE a priori,' rather, the direction becomes known once the UE detects a DCI scheduling / triggering a particular DL or UL signal / channel. In contrast, the DL / UL direction for some or all of the 'F' symbols in a particular slot can be provided to the UE in a semi-static manner by RRC configuring the UE with TDD-DL-UL-ConfigDedicated. The lower part of FIG. 2 shows three example configurations for overriding 'F' symbols in Slot 3. If the IE indicates 'allDownlink' or 'allUplink' for a particular slot (or slots), then all 'F' symbols in the slot may be converted to either 'D' or U,' respectively. If the IE indicates 'explicit,' then a number of symbols at the beginning of the slot and / or a number of symbols at the end of the slot are indicated as 'D' and U,' respectively. In the example below, the first 7 and the last 5 are indicated as 'D' and 'U, which converts some of the 'F' symbols (but not all in this example) to 'D' and U.'

[0020] A notable behavior in the above is that the UE-specific IE TDD-DL-UL- ConfigDedicated may only be able to override (i.e., specify 'D' or 'U') for symbols that are configured as 'F' by the cell-specific IE TDD-DL-UL-ConfigCommon. In other words, a UE may not expect to have a 'D' symbol converted to U' or vice versa.

[0021] Subband full duplex

[0022] As described above, in a conventional TDD system, the entire carrier BW or all carriers in the same frequency band may need to be utilizing the same DL transmission or UL reception directions. This is further illustrated in FIG. 3, which shows 3GPP Release 18 (Rel-18) evolution of the NR system. 3GPP has decided to study the technical feasibilities and potential benefits of subband full duplex (SBFD) systems.

[0023] • In such a system, a portion of a wide bandwidth carrier may be used for a different direction than that of the rest of the carrier. This is illustrated in the left-hand side of FIG. 4, which depicts subband full duplex systems.. That is, unlike a conventional TDD system as shown on the left-hand side of FIG. 3 (where the entire bandwidth is used for DL transmission in the first three slots), the center portion of the SBFD carrier is used for UL reception, while the rest of the carrier continues to be used for DL transmission, as shown in the left-hand side of FIG. 4.

[0024] • Similarly, instead of utilizing all carriers for the same DL or UL directions in a conventional TDD system, as shown in the right-hand side of FIG. 3, some carriers in the SBFD system can be used for a different direction than that of the other carriers, as shown in the right-hand side of FIG. 4.

[0025] In the 3GPP Rel-18 study, the scope has been limited such that in SBFD operation, only network nodes transmit DL and receive UL simultaneously. An individual UE is scheduled in only one direction (DL or UL) at a time. For subband full duplex (SBFD) work item (WI) in 3GPP Release 19 (Rel-19), an SBFD-capable UE in a cell capable of SBFD operation would be able to perform UL transmissions in both non SBFD symbols (e.g., configured as UL or flexible by TDD-DL- UL common) and SBFD slots / symbols (i.e., configured as DL by TDD-DL-UL common).

[0026] 3 GPP RAN2 has agreed to apply SBFD operation for contention-free Random Access (RA). However, in the legacy, contention-free RA is configured by the network node via Radio Resource Control (RRC) signaling (e.g., RRCReconfigurationwithSync) including a field rach-ConfigDedicated, which comprises dedicated Physical Random Access Channel (PRACH) resources, based on which, the UE can initiate a contention- free RA.

[0027] As another example, dedicated PRACH resources can be also configured to the UE for beam failure recovery (e.g., candidateBeamRSList in BeamFailureRecoveryConfig indicates set of reference signals (Channel State Information Reference Signals (CSI-RS) and / or Synchronization Signal Block (SSB)) identifying the candidate beams for recovery and the associated RA parameter) so that the UE an apply contention-free RA for beam failure recovery.

[0028] As yet another example, the network node can send a PDCCH order to the UE indicating a contention-free RA to be triggered. The legacy PDCCH order cannot indicate the triggered RA is for SBFD or non- SBFD.

[0029] For either of the above cases, a SBFD-capable UE is not able to interpret whether the configured dedicated PRACH resources based on the legacy signaling, is for SBFD operation or for non SBFD operation. As a further consequence, the UE will not know to apply legacy RA configuration or sub-band full duplex (SBFD) RA configuration. Different UEs may have different behaviors for RA resource selection. When there are different power control parameters for legacy RA operation and SBFD RA operation, some UEs may apply legacy power control parameters for its RA operation, while other UEs may apply SBFD RA specific power control parameters.

[0030] SUMMARY

[0031] In consideration of the above, signaling enhancements may be needed for the network node to indicate whether the dedicated PRACH resources are intended for SBFD and / or non SBFD.

[0032] Hence, some embodiments advantageously provide methods, systems, and apparatuses for contention-free random access (RA). An indicator may be included in the dedicated RA configuration or a PDCCH order signaled to a UE, indicating the RA resource types for the contention-free RA initiated by the UE according to the dedicated RA configuration or the PDCCH order.

[0033] The indicator indicating the resource type (e.g., SBFD resources or non- SBFD / legacy resources) for the dedicated RA configuration may include any combination of the below:

[0034] 1) Non-SBFD RA resource / legacy RA resource

[0035] In this case, the UE may use the legacy RA resources as indicated in the dedicated RA configuration to perform the contention-free-based RA.

[0036] 2) SBFD RA resource

[0037] In this case, the UE may use the SBFD RA resources as indicated in the dedicated RA configuration to perform the contention-free-based RA.

[0038] 3) The first priority of resources is legacy RA resources, and the second priority of resource is SBFD RA resources.

[0039] In this case, the UE may first use the legacy RA resources (as indicated in the dedicated RA configuration) to perform the contention-free RA. If the UE experiences failures for the RA when using the legacy RA resources, the UE switches to SBFD resources to continue the RA.

[0040] 4) The first priority of resources is SBFD RA resources, and the second priority of resource is legacy RA resources.

[0041] In this case, the UE may first use the SBFD RA resources (as indicated in the dedicated RA configuration) to perform the contention-free RA. If the UE experiences failures for the RA when using the SBFD RA resources, the UE switches to legacy resources to continue the RA.

[0042] When a contention-free RA procedure is initiated by the UE according to the dedicated RA configuration or the PDCCH order, the UE performs the contention-free RA using the RA resources as indicated by the RA resource type in the dedicated RA configuration or the PDCCH order, as applicable.

[0043] Embodiments described herein have at least one or more of the following advantages:

[0044] • Enabling the network / the network node to provide indicators to the UE indicating the contention-free RA resource type (i.e., either non-SBFD RA resources or SBFD RA resources) • Improved / aligned UE behaviors on contention-free RA resource selection among all UEs (SBFD RA capable)

[0045] • Enabling the network node and the UEs to use the RA resources more efficiently.

[0046] In accordance with one aspect of the present disclosure, a method implemented in a UE that is configured to communicate with a network node, is provided. The method includes receiving control signaling from the network node, selecting between RA resource types for a contention-free RA procedure based on the received control signaling, and performing the contention-free RA procedure based on the selection.

[0047] In some embodiments of this aspect, the control signaling includes an indicator indicating the RA resource type for the contention-free RA procedure, the selection between the RA resource types for the contention-free RA procedure being based on the indicator.

[0048] In some embodiments, the RA resource types are one of SBFD or non-SBFD.

[0049] In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, and the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0050] In some embodiments, the method further includes switching to the SBFD RA resources to continue the RA based on the UE experiencing a failure for the contention- free RA procedure when using the non-SBFD RA resources.

[0051] In some embodiments, the method further includes switching to the non-SBFD RA resources to continue the RA based on the UE experiencing a failure for the contention- free RA procedure when using the SBFD RA resources.

[0052] In some embodiments, the indicator is included in one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order signaled to the UE.

[0053] In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel, PRACH, preamble and a random access channel, RACH, occasion.

[0054] In some embodiments, the method further includes, when a contention-free RA event associated with the dedicated RA configuration is triggered, performing the contention-free RA procedure using the RA resources as indicated by the RA resource type in the dedicated RA configuration.

[0055] In accordance with another aspect of the present disclosure, a UE- configured to communicate with a network node is provided. The UE is configured to, and / or comprises a radio interface and / or processing circuitry (50) configured to receive control signaling from the network node, select between RA resource types for a contention-free RA procedure based on the received control signaling, and perform the contention-free RA procedure based on the selection.

[0056] In some embodiments of this aspect, the control signaling includes an indicator indicating the RA resource type for the contention-free RA procedure, the selection between the RA resource types for the contention-free RA procedure being based on the indicator.

[0057] In some embodiments, the RA resource types are one of: SBFD, or non-SBFD.

[0058] In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, and the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0059] In some embodiments, the UE is further configured to switch to the SBFD RA resources to continue the RA based on the UE experiencing a failure for the contention- free RA procedure when using the non-SBFD RA resources.

[0060] In some embodiments, the UE is further configured to switch to the non-SBFD RA resources to continue the RA based on the UE experiencing a failure for the contention- free RA procedure when using the SBFD RA resources.

[0061] In some embodiments, the indicator is included in one of a dedicated RA configuration and a PDCCH order signaled to the UE.

[0062] In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a PRACH preamble and RACH occasion.

[0063] In some embodiments, the UE is further configured to, when a contention-free RA event associated with the dedicated RA configuration is triggered, perform the contention- free RA procedure using the RA resources as indicated by the RA resource type in the dedicated RA configuration. In accordance with another aspect of the present disclosure, a method implemented in a network node that is configured to communicate with UE is provided. The method includes transmitting control signaling to the UE for selection between RA resource types for a contention-free RA procedure based on the control signaling, and receiving contention free RA signaling from the UE based on the UE selection.

[0064] In some embodiments of this aspect, the method further includes an indicator in the control signaling, the indicator indicating the RA resource type for the contention-free RA procedure for selecting between the RA resource types for the contention-free RA procedure based on the indicator.

[0065] In some embodiments, the RA resource types are one of SBFD, or non-SBFD.

[0066] In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0067] In some embodiments, the indicator is one of a dedicated RA configuration and a PDCCH order.

[0068] In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a PRACH preamble and a RACH occasion.

[0069] In some embodiments, the RA resource type is determined based on whether all neighboring cells are cells supporting SBFD RA.

[0070] In some embodiments, the method further includes determining whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell supports SBFD operation.

[0071] In some embodiments, the method further includes determining whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell is SBFD RA operation enabled.

[0072] In some embodiments, the method further includes indicating in a handover request, whether the UE prefers to have an SBFD RA capable / enabled cell as a target cell.

[0073] In accordance with another aspect of the present disclosure, a network node configured to communicate with a UE, is provided. The network node is configured to, and / or comprises a radio interface and / or comprises processing circuitry configured to transmit control signaling to the UE for selection between RA resource types for a contention-free RA procedure based on the control signaling and receive contention free RA signaling from the UE based on the UE selection.

[0074] In some embodiments of this aspect, the network node is further configured to include an indicator in the control signaling, the indicator indicating the RA resource type for the contention-free RA procedure for selecting between the RA resource types for the contention-free RA procedure based on the indicator.

[0075] In some embodiments, the RA resource types are one of SBFD or non-SBFD.

[0076] In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0077] In some embodiments, the indicator is one of a dedicated RA configuration and a PDCCH order.

[0078] In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a PRACH preamble and RACH occasion.

[0079] In some embodiments, the RA resource type is determined based on whether all neighboring cells are cells supporting SBFD RA.

[0080] In some embodiments, the network node is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell supports SBFD operation.

[0081] In some embodiments, the network node is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell is SBFD RA operation enabled.

[0082] In some embodiments, the network node is further configured to indicate in a handover request, whether the UE prefers to have an SBFD RA capable / enabled cell as a target cell.

[0083] BRIEF DESCRIPTION OF THE DRAWINGS

[0084] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: FIG. l is a block diagram of frequency and time-division duplex;

[0085] FIG. 2 is a block diagram of an example TDD DL / UL pattern;

[0086] FIG. 3 is a block diagram of an example conventional TDD carrier or carrier systems;

[0087] FIG. 4 is a block diagram of an example subband full duplex system;

[0088] FIG. 5 is a schematic diagram of an example network architecture illustrating a communication system according to principles disclosed herein;

[0089] FIG. 6 is a block diagram of a network node in communication with a user equipment over a wireless connection according to some embodiments of the present disclosure;

[0090] FIG. 7 is a flowchart of an example process in a network node according to some embodiments of the present disclosure;

[0091] FIG. 8 is a flowchart of an example process in a user equipment according to some embodiments of the present disclosure;

[0092] FIG. 9 is a flowchart of another example process in a network node according to some embodiments of the present disclosure; and

[0093] FIG. 10 is a flowchart of another example process in a user equipment according to some embodiments of the present disclosure.

[0094] DETAILED DESCRIPTION

[0095] Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to contention-free random access (RA). Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0096] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0097] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0098] In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0099] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0100] The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multistandard radio (MSR) radio node such as MSR BS, multi -cell / multicast coordination entity (MCE), relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a user equipment (UE) such as a wireless device (WD) or a radio network node.

[0101] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of user equipment capable of communicating with a network node or another UE over radio signals, such as a wireless device (WD). The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low-cost and / or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device etc.

[0102] Also, in some embodiments, the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell / multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[0103] Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0104] According to one or more embodiments of this aspect, the general description elements in the form of “one of A and B” corresponds to A or B. According to one or more embodiments of this aspect, at least one of A and B corresponds to A, B or AB, or to one or more of A and B, or one or both of A and B . According to one or more embodiments of this aspect, at least one of A, B and C corresponds to one or more of A, B and C, and / or A, B, C or a combination thereof.

[0105] Note further, that functions described herein as being performed by a user equipment or a network node may be distributed over a plurality of user equipments and / or network nodes. In other words, it is contemplated that the functions of the network node and user equipment described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

[0106] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0107] Some embodiments are directed to contention-free random access (RA).

[0108] Referring to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 5 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first user equipment (UE) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second UE 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of UEs 22a, 22b (collectively referred to as user equipments 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding network node 16. Note that although only two UEs 22 and three network nodes 16 are shown for convenience, the communication system may include many more UEs 22 and network nodes 16.

[0109] Also, it is contemplated that a UE 22 can be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a UE 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, UE 22 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN. A network node 16 (eNB or gNB) is configured to include a configuration unit 24 which is configured to perform one or more network node 16 functions described herein, including functions related to contention-free RA. A user equipment 22 is configured to include an implementation unit 26 which is configured to perform one or more UE 22 functions described herein, including functions related to contention-free RA.

[0110] Example implementations, in accordance with an embodiment, of the UE 22 and network node 16 discussed in the preceding paragraphs will now be described with reference to FIG. 6.

[0111] The communication system 10 includes a network node 16 provided in a communication system 10 and including hardware 28 enabling it to communicate with the UE 22. The hardware 28 may include a radio interface 30 for setting up and maintaining at least a wireless connection 32 with a UE 22 located in a coverage area 18 served by the network node 16. The radio interface 30 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 30 includes an array of antennas 34 to radiate and receive signal(s) carrying electromagnetic waves.

[0112] In the embodiment shown, the hardware 28 of the network node 16 further includes processing circuitry 36. The processing circuitry 36 may include a processor 38 and a memory 40. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 36 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 38 may be configured to access (e.g., write to and / or read from) the memory 40, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0113] Thus, the network node 16 further has software 42 stored internally in, for example, memory 40, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 42 may be executable by the processing circuitry 36. The processing circuitry 36 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by network node 16. Processor 38 corresponds to one or more processors 38 for performing network node 16 functions described herein. The memory 40 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 42 may include instructions that, when executed by the processor 38 and / or processing circuitry 36, causes the processor 38 and / or processing circuitry 36 to perform the processes described herein with respect to network node 16. For example, processing circuitry 36 of the network node 16 may include configuration unit 24 which is configured to perform one or more network node 16 functions described herein, including functions related to contention-free RA.

[0114] The communication system 10 further includes the UE 22 already referred to. The UE 22 may have hardware 44 that may include a radio interface 46 configured to set up and maintain a wireless connection 32 with a network node 16 serving a coverage area 18 in which the UE 22 is currently located. The radio interface 46 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 46 includes an array of antennas 48 to radiate and receive signal(s) carrying electromagnetic waves.

[0115] The hardware 44 of the UE 22 further includes processing circuitry 50. The processing circuitry 50 may include a processor 52 and memory 54. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 50 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 52 may be configured to access (e.g., write to and / or read from) memory 54, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0116] Thus, the UE 22 may further comprise software 56, which is stored in, for example, memory 54 at the UE 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the UE 22. The software 56 may be executable by the processing circuitry 50. The software 56 may include a client application 58. The client application 58 may be operable to provide a service to a human or non-human user via the UE 22.

[0117] The processing circuitry 50 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by UE 22. The processor 52 corresponds to one or more processors 52 for performing UE 22 functions described herein. The UE 22 includes memory 54 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 56 and / or the client application 58 may include instructions that, when executed by the processor 52 and / or processing circuitry 50, causes the processor 52 and / or processing circuitry 50 to perform the processes described herein with respect to UE 22. For example, the processing circuitry 50 of the user equipment 22 may include implementation unit 26 which is configured to perform one or more UE 22 functions described herein, including functions related to contention-free RA.

[0118] In some embodiments, the inner workings of the network node 16 and UE 22 may be as shown in FIG. 6 and independently, the surrounding network topology may be that of FIG. 5.

[0119] The wireless connection 32 between the UE 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve.

[0120] Although FIGS. 5 and 6 show various “units” such as configuration unit 24 and implementation unit 26 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

[0121] FIG. 7 is a flowchart of an example process in a network node 16. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 36 (including the configuration unit 24), processor 38, and / or radio interface 30. Network node 16 is configured to transmit (Block SI 00) control signaling to the UE 22 for selection between random access (RA) resource types for a contention-free RA procedure based on the control signaling. Network node 16 is further configured to receive (Block SI 02) contention free RA signaling from the UE 22 based on the UE 22 selection. In some embodiments, network node 16 is further configured to include an indicator in the control signaling, the indicator indicating the RA resource type for the contention-free RA procedure for selecting between the RA resource types for the contention-free RA procedure based on the indicator. In some embodiments, the RA resource types are one of subband full duplex (SBFD), or non-SBFD. In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0122] In some embodiments, the indicator is one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order. In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel (PRACH) preamble and a random access channel (RACH) occasion. In some embodiments, the RA resource type is determined based on whether all neighboring cells are cells supporting SBFD RA. In some embodiments, network node 16 is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell supports SBFD operation. In some embodiments, network node 16 is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell is SBFD RA operation enabled. In some embodiments, network node 16 is further configured to indicate in a handover request, whether the UE 22 prefers to have an SBFD RA capable / enabled cell as a target cell.

[0123] FIG. 8 is a flowchart of an example process in a user equipment 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of UE 22 such as by one or more of processing circuitry 50 (including the implementation unit 26), processor 52, and / or radio interface 46. UE 22 is configured to receive (Block SI 04) control signaling from the network node 16. UE 22 is further configured to select (Block SI 06) between random access (RA) resource types for a contention-free RA procedure based on the received control signaling. UE 22 is further configured to perform (Block SI 08) the contention-free RA procedure based on the selection.

[0124] In some embodiments, the control signaling includes an indicator indicating the RA resource type for the contention-free RA procedure, the selection between the RA resource types for the contention-free RA procedure being based on the indicator. In some embodiments, the RA resource types are one of subband full duplex (SBFD), non-SBFD. In some embodiments, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources, and the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0125] In some embodiments, the UE 22 is further configured to switch to the SBFD RA resources to continue the RA based on the UE experiencing a failure for the contention- free RA procedure when using the non-SBFD RA resources. In some embodiments, the UE 22 is further configured to switch to the non-SBFD RA resources to continue the RA based on the UE 22 experiencing a failure for the contention-free RA procedure when using the SBFD RA resources. In some embodiments, the indicator is included in one of a dedicated RA configuration and a physical downlink control channel (PDCCH) order signaled to the UE 22. In some embodiments, the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel (PRACH) preamble and a random access channel (RACH) occasion. In some embodiments, the UE 22 is further configured to, when a contention-free RA event associated with the dedicated RA configuration is triggered, perform the contention-free RA procedure using the RA resources as indicated by the RA resource type in the dedicated RA configuration.

[0126] FIG. 9 is a flowchart of another example process in a network node 16. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 36 (including the configuration unit 24), processor 38, and / or radio interface 30. Network node 16 is configured to transmit (Block SI 10), to the UE 22, an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure. Network node 16 is further configured to communicate (Block SI 12) with the UE 22 based on the contention-free RA procedure using the indicated RA resource types.

[0127] In at least one embodiment, the RA resource types are one of: subband full duplex (SBFD); or non-SBFD. In at least one embodiment, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0128] FIG. 10 is a flowchart of another example process in a UE 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of user equipment 22 such as by one or more of processing circuitry 50 (including the implementation unit 26), processor 52, and / or radio interface 46. User equipment 22 is configured to receive (Block SI 14) an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure. User equipment 22 is further configured to initiate (Block SI 16) the contention-free RA procedure using the indicated RA resource types.

[0129] In at least one embodiment, the RA resource types are one of subband full duplex (SBFD) or non-SBFD.

[0130] In at least one embodiment, the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0131] Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for contention-free RA. One or more UE 22 functions described below may be performed by one or more of processing circuitry 50, processor 52, implementation unit 26, etc. One or more network node 16 functions described below may be performed by one or more of processing circuitry 36, processor 38, configuration unit 24, etc.

[0132] A UE 22 may be “SBFD aware” if it is capable of operating in a cell configured with SBFD feature. That is, the cell / the network node 16 transmits DL and receives UL simultaneously in SBFD slots and symbols within a carrier. The UE 22 can be aware of SBFD configurations so that the UE 22 knows which slots / symbols are SBFD capable, which are also referred to as SBFD slots / symbols. However, the UE 22 does not necessarily need to support full duplex operation. That is, the UE 22 may or may not support full duplex operation.

[0133] Below are some example embodiments of SBFD-aware UEs 22.

[0134] Examples on dedicated RA configuration

[0135] In an example embodiment, an indicator is included in the dedicated RA configuration signaled to a UE 22. The indicator indicates the RA resource types for the dedicated RA configuration.

[0136] The indicator that indicates the resource type (e.g., SBFD resources or non- SBFD / legacy resources) for the dedicated RA configuration may include one of:

[0137] • Non SBFD RA resource / legacy RA resource

[0138] In this case, the UE 22 may use the legacy RA resources as indicated in the dedicated RA configuration to perform the contention-free based RA.

[0139] • SBFD RA resource

[0140] In this case, the UE 22 may use the SBFD RA resources as indicated in the dedicated RA configuration to perform the contention-free based RA.

[0141] • The first priority of resources is legacy RA resources. The second priority of resources is SBFD RA resources.

[0142] In this case, the UE 22 may first use the legacy RA resources (as indicated in the dedicated RA configuration) to perform the contention-free RA. If the UE 22 experiences failures for the RA when using the legacy RA resources, the UE 22 switches to SBFD resources to continue the RA.

[0143] • The first priority of resources is SBFD RA resources. The second priority of resources is legacy RA resources.

[0144] In this case, the UE 22 may first use the SBFD RA resources (as indicated in the dedicated RA configuration) to perform the contention free RA. If the UE 22 experiences failures for the RA when using the SBFD RA resources, the UE 22 switches to legacy resources to continue the RA.

[0145] When a contention free RA event associated with the dedicated RA configuration is triggered, the UE 22 performs the contention free RA using the RA resources as indicated by the RA resource type in the dedicated RA configuration.

[0146] In at least one embodiment, if the dedicated RA configuration does not include the RA resource type indicator, the UE 22 performs the contention free RA using the RA resources determined by its implementation (i.e., either legacy RA resources or SBFD RA resources). In at least one embodiment, the dedicated RA configuration includes the indicator indicating the resource type for the contention-free RA. The indicated RA resources may include at least one of

[0147] • PRACH preamble; and / or

[0148] • RACH occasion (in time domain and / or frequency domain).

[0149] In at least one embodiment, an example of the Abstract Syntax Notation One (ASN.l) code implementing the proposed RA resource type indicator, e.g., in the RRC as specified by 3GPP specification 18.2.0, for IE RACH-ConfigDedicated is illustrated below.

[0150] - RACH-ConfigDedicated

[0151] The IE RACH-ConfigDedicated is used to specify the dedicated random access parameters.

[0152] RACH-ConfigDedicated information element

[0153] - ASN1 START

[0154] - TAG-RACH-CONFIGDEDICATED-START

[0155] RACH-ConfigDedicated ::= SEQUENCE ) cfra CFRA

[0156] OPTIONAL, - Need S ra-Prioritization RA-Prioritization

[0157] OPTIONAL, - Need N

[0158] [[ ra-PrioritizationTwoStep-r 16 RA-Prioritization OPTIONAL, - Need N cfra-TwoStep-rl6 CFRA-TwoStep-rl6

[0159] OPTIONAL - Need S

[0160] ]],

[0161] [[ cfra-Resource-Type-rl9 ENUMERATED {non-SBFD, SBFD, non- SBFD and SBFD, SBFD and non-SBFD}

[0162] OPTIONAL - Cond SBFDCarrier

[0163] ]] }

[0164] CFRA ::= SEQUENCE { occasions SEQUENCE { rach-ConfigGeneric RACH-ConfigGeneric, ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight, sixteen}

[0165] OPTIONAL - Cond Mandatory

[0166] } OPTIONAL, -

[0167] Need S resources CHOICE { ssb SEQUENCE { ssb-ResourceList SEQUENCE (SIZE(1. maxRA-SSB-

[0168] Resources)) OF CFRA- SSB -Resource, ra-ssb-OccasionMasklndex INTEGER (0..15) }, csirs SEQUENCE { csirs-ResourceList SEQUENCE (SIZE(l ..maxRA-CSIRS-

[0169] Resources)) OF CFRA-CSIRS-Resource, rsrp-ThresholdCSLRS RSRP -Range

[0170] } }, ... , [[ totalNumberOfRA-Preambles INTEGER (L.63)

[0171] OPTIONAL — Cond Occasions ]], [[ msgl-RepetitionNum-rl8 ENUMERATED {n2, n4, n8, sparel }

[0172] OPTIONAL - Cond 4StepCFRArep ]] } CFRA-TwoStep-rl6 ::= SEQUENCE { occasionsTwoStepRA-rl6 SEQUENCE { rach-ConfigGenericTwoStepRA-rl6 RACH-ConfigGenericTwoStepRA- rl6, ssb-PerRACH-OccasionTwoStepRA-rl6 ENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight, sixteen} } OPTIONAL, -

[0173] Need S msgA-CFRA-PUSCH-rl6 MsgA-PUSCH-Resource-rl6, msgA-TransMax-rl6 ENUMERATED {nl, n2, n4, n6, n8, nlO, n20, n50, nlOO, n200} OPTIONAL, - Need S resourcesTwoStep-rl6 SEQUENCE { ssb-ResourceList SEQUENCE (SIZE(1. maxRA-SSB-

[0174] Resources)) OF CFRA-S SB -Resource, ra-ssb-OccasionMasklndex INTEGER (0..15)

[0175] }, } CFRA-SSB-Resource ::= SEQUENCE } ssb S SB -Index, ra-Preamblelndex INTEGER (0..63),

[0176] ... , [[ msgA-PUSCH-Resource-Index-rl6 INTEGER (0 .3071) OPTIONAL - Cond 2StepCFRA ]] } CFRA-CSIRS-Resource ::= SEQUENCE } csi-RS CSI-RS-Index, ra-OccasionList SEQUENCE (SIZE(L .maxRA-OccasionsPerCSIRS))

[0177] OF INTEGER (O. maxRA-Occasions-1), ra-Preamblelndex INTEGER (0..63), }

[0178] - TAG-RACH-CONFIGDEDICATED-STOP

[0179] - ASN1STOP

[0180]

[0181]

[0182] In at least one embodiment, an example of the ASN.1 code implementing the proposed RA resource type indicator, e.g., as specified in the 3GPP RRC specification vl 8.2.0 for IE BeamFailureRecoveryConfig, is illustrated below.

[0183] Upon detection of Beam Failure Recovery (BFR), the UE 22 triggers a contention- free RA for the BFR. The UE 22 uses the RA resources according to the type as indicated by dedicatedBFR-Resource-Type-rl9 in BeamFailureRecoveryConfig.

[0184] - BeamFailureRecoveryConfig

[0185] The IE BeamFailureRecoveryConfig is used to configure the UE 22 with RACH resources and candidate beams for beam failure recovery in case of beam failure detection. See, e.g., 3GPP Technical Specification (TS) 38.321 clause 5.1.1.

[0186] BeamFailureRecoveryConfig information element

[0187] - ASN1 START

[0188] - TAG-BEAMFAILURERECOVERYCONFIG-START

[0189] BeamFailureRecoveryConfig ::= SEQUENCE { rootSequencelndex-BFR INTEGER (0 .137)

[0190] OPTIONAL, - Need M rach-ConfigBFR RACH-ConfigGeneric

[0191] OPTIONAL, - Need M rsrp-ThresholdSSB RSRP -Range

[0192] OPTIONAL, - Need M candi dateB eamRSLi st SEQUENCE

[0193] (SIZE(L.maxNrofCandidateBeams)) OF PRACH-ResourceDedicatedBFR OPTIONAL,

[0194] — Need M ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth. oneHalf, one, two, four, eight, sixteen}

[0195] OPTIONAL, - Need M ra-ssb-OccasionMasklndex INTEGER (0 .15)

[0196] OPTIONAL, - Need M recovery Search Spaceld SearchSpaceld

[0197] OPTIONAL, - Need R ra-Prioritization RA-Pri oritizati on

[0198] OPTIONAL, - Need R beamFailureRecoveryTimer ENUMERATED {mslO, ms20, ms40, ms60, ms80, mslOO, msl50, ms200} OPTIONAL, — Need M

[0199] [[ msgl-SubcarrierSpacing SubcarrierSpacing OPTIONAL - Need M ]], [[ ra-PrioritizationTwoStep-r 16 RA-Prioritization

[0200] OPTIONAL, - Need R candidate! eamRSListExt-vl 610 SetupRelease{ CandidateBeamRSListExt- rl6 } OPTIONAL - Need M

[0201] ]], [[ spCell-BFR-CBRA-rl6 ENUMERATED {true}

[0202] OPTIONAL — Need R ]], [[ dedicatedBFR-Resource-Type-rl9 ENUMERATED {non-SBFD, SBFD, non-SBFD and SBFD, SBFD and non-SBFD}

[0203] OPTIONAL - Cond SBFDCarrier ]] } PRACH-ResourceDedicatedBFR ::= CHOICE { ssb BFR-S SB -Resource, csi-RS BFR-C SIRS -Resource

[0204] } BFR-SSB-Resource ::= SEQUENCE } ssb SSB -Index, ra-Preamblelndex INTEGER (0..63),

[0205] } BFR-CSIRS-Resource ::= SEQUENCE } csi-RS NZP-CSI-RS-Resourceld, ra-OccasionList SEQUENCE (SIZE(l..maxRA-

[0206] OccasionsPerCSIRS)) OF INTEGER (O. maxRA-Occasions-1) OPTIONAL, — Need R ra-Preamblelndex INTEGER (0..63) OPTIONAL, - Need R

[0207] }

[0208] CandidateBeamRSListExt-rl6: := SEQUENCE (SIZE(L. maxNrofCandidateBeamsExt-rl6)) OF PRACH-ResourceDedicatedBFR

[0209] - TAG-BEAMFAILURERECOVERYCONFIG-STOP

[0210] - ASN1STOP

[0211]

[0212] In the at least one embodiment, the UE 22 receives a dedicated RA configuration from the network node via RRC signaling. The dedicated RA configuration may not contain any indicator indicating whether the UE 22 is to use non-SBFD resources or SBFD RA resources. In this case, upon triggering of a contention-free RA event, the UE 22 may determine the RA resource type based on the type of the subsequent available RACH Occasion (RO) / RA resources. An RO may be an area specified in the time and frequency domain that is available for the reception and / or transmission of a RACH preamble. The RA resource may contain one or more of a PRACH preamble, RACH occasions, PRACH sequences, etc. In other words, if the subsequent available RO / RA resource type is non-SBFD type, the UE 22 may use only non-SBFD RA resources to complete the RA procedure. If the subsequent available RO / RA resource type is SBFD type, the UE 22 may use only SBFD RA resources to complete the RA procedure.

[0213] In at least one embodiment, the UE receives at least a dedicated RA configuration from the network node 16 via RRC signaling for SBFD RA operation. In addition, the UE 22 receives at least a separate dedicated RA configuration from the network node 16 via RRC signaling for non SBFD RA operation.

[0214] Example Embodiments for PDCCH order-triggered contention-free RA

[0215] The network node 16 initiates PDCCH order by sending a Downlink Control Information (DCI) (e.g., with format 1 0) on the SSB beam index on which UE 22 is camped, along with a PRACH preamble and RACH occasion information. The content of the DCI Format 1 0 for RACH procedure as specified in, e.g., 3GPP TS 38.212 V18.4.0 is as follows. In at least one embodiment, the RA resources, e.g., Random Access Preamble index in this case, are associated with an indicator indicating the resource type for the RACH by PDCCH. In this embodiment, PRACH / RA resources (e.g., PRACH preamble) are split between non-SBFD RA operation and SBFD RA operation. Based on the resources indicated by PDCCH order, the UE 22 can determine that the contention-free RA transmissions (triggered by the PDCCH order) may use non-SBFD resources or SBFD resources.

[0216] The indicator may occupy at least one bit, which may be implemented in various places in the DCI (e.g., DCI with format 1 0). Below are some options.

[0217] • The indicator occupies bits out of the Reserved bits.

[0218] • The indicator is / are contained by an existing DCI field, by repurposing a part or full of the existing field, e.g., the UL / SUL indicator field is updated with the indicator. o As another example, bits from other existing fields, including SS / PBCH index, PRACH mask index, PRACH association indicator, or PRACH retransmission indicator may be used. In this example, either the existing field is not used, or the existing field has some free bits (which may be a result of resource volume allocated to SBFD operation / non SBFD operation not using the full bits).

[0219] In at least one embodiment, the indicator (with 1 bit) uses ‘0’ and ‘ 1’ to indicates the association with SBFD. In an example, the indicator uses ‘0’ to indicate non-SBFD RA resources, e.g., non-SBFD RO, and the indicator uses ‘ 1’ to indicate SBFD RA resources, e.g., SBFD RO. In another example, the indicator with the value ‘O'indicates SBFD RA resources, while the indicator with the value ‘ 1’ indicates SBFD resources.

[0220] In yet another example, the absence of the indicator in the DCI means the UE 22 determines what type of RA resources to use by its implementation (i.e., either non-SBFD RA resources or SBFD RA resources). Alternatively, the absence of the indicator in the DCI means that the UE 22 may use only non-SBFD RA resources.

[0221] In another example, the indicator contains multiple bits and indicates the same information as described in one or more embodiments described herein.

[0222] Examples for the network node 16

[0223] In an embodiment related to inter-cell mobility / handover, including conditional handover, and L1 / L2 triggered mobility, the UE 22 may be provided with a specific RA prioritization order or RA scheme as a part of the RRC -based candidate cell configuration, e.g., in a RRCReconfiguration message. The candidate cell configuration may include the same configuration as the candidate cell is providing in System Information Blocks (SIB), or may be a different configuration, dedicated for inter-cell mobility. Upon receiving a handover command from the serving cell, the UE 22 accesses the candidate cell according to the received candidate cell configuration.

[0224] In at least one embodiment, the network node 16 may select the configuration of cfra-Resource-Type-rl9 (e.g., as described in other embodiments here), related to its surroundings. In case not all neighbor cells are SBFD cells, or they support SBFD random access, legacy SBFD may be included in the configuration. Whereas, if all cells are SBFD cells with SBFD RA configured, only SBFD resources may be configured.

[0225] As at least one embodiment for a UE 22 (which is SBFD operation capable), a serving cell / network node 16 may consider at least one of the below information on a neighbor cell to decide whether the neighbor cell can be a handover target cell candidate:

[0226] 1) Whether the neighbor cell is SBFD feature / operation capable (e.g., based on information provided by 0AM or information / signaling provided by the neighbor cell) a. Alternatively, whether the neighbor cell supports SBFD operation, is signaled to the cell / the network node 16 by the UE 22. The UE 22 may obtain this information before the handover (e.g., provisioned from the Core Network (CN)).

[0227] 2) Whether the neighbor cell is SBFD RA operation enabled (e.g., based on information provided by Operations, Administration, and Maintenance (0AM) or information / signaling provided by the neighbor cell) a. In an example, it may occur that the neighbor cell is SBFD operation capable. However, the neighbor cell may have decided to disable SBFD RA operation.

[0228] In an example, the serving cell / network node 16 decides to select a neighbor cell (which supports SBFD RA) as a target cell for a UE 22. In this case, the serving cell may include an indicator in the handover request message indicating whether the UE 22 is SBFD (RA) capable, so that the target cell can decide whether to assign SBFD CBRA resources to the UE 22 for this handover. The UE 22 may also indicate its preference on target cells to the serving cell / network node 16, e.g., whether the UE 22 prefers to have a SBFD (RA) capable / enabled cell as a target cell. In such case, the serving cell / network node 16 may also include the UE’s 22 preference info on target cells in the handover request message.

[0229] Some Examples Example Al . A method implemented in a user equipment (UE) that is configured to communicate with a network node, the method comprising: receiving an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure; and initiating the contention-free RA procedure using the indicated RA resource types.

[0230] Example A2. The method of Example Al, wherein the RA resource types are one of subband full duplex (SBFD); or non-SBFD.

[0231] Example A3. The method of Example A2, wherein the indicator indicates a first priority of resources and a second priority of resources, and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0232] Example Bl. A user equipment (UE) configured to communicate with a network node, the UE configured to, and / or comprising a radio interface and / or processing circuitry configured to: receive an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure; and initiate the contention-free RA procedure using the indicated RA resource types.

[0233] Example B2. The UE of Example Bl, wherein the RA resource types are one of: subband full duplex (SBFD); or non-SBFD.

[0234] Example B3. The UE of Example B 1 , wherein the indicator indicates a first priority of resources and a second priority of resources, and one of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0235] Example Cl . A method implemented in a network node that is configured to communicate with a user equipment, the method comprising: transmitting, to the UE, an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure; and communicating with the UE based on the contention-free RA procedure using the indicated RA resource types.

[0236] Example C2. The method of Example Cl, wherein the RA resource types are one of: subband full duplex (SBFD); or non-SBFD.

[0237] Example C3. The method of Example Cl, wherein the indicator indicates a first priority of resources and a second priority of resources, and one of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

[0238] Example DI . A network node configured to communicate with a user equipment (UE), the network node configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to: transmit, to the UE, an indicator in one of a dedicated random access (RA) configuration or a physical downlink control channel (PDCCH) order, the indicator indicating RA resource types for a contention-free RA procedure; and communicate with the UE based on the contention-free RA procedure using the indicated RA resource types.

[0239] Example D2. The network node of Example DI, wherein the RA resource types are one of: subband full duplex (SBFD); or non-SBFD.

[0240] Example D3. The network node of Example DI, wherein the indicator indicates a first priority of resources and a second priority of resources, and one of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources. As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0241] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0242] These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0243] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0244] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0245] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0246] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0247] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

Claims1. A method implemented in a user equipment, UE, (22) that is configured to communicate with a network node (16), the method comprising: receiving (SI 04) control signaling from the network node (16); selecting (SI 06) between random access, RA, resource types for a contention-free RA procedure based on the received control signaling; and performing (SI 08) the contention-free RA procedure based on the selection.

2. The method of Claim 1, wherein the control signaling includes an indicator indicating the RA resource type for the contention-free RA procedure, the selection between the RA resource types for the contention-free RA procedure being based on the indicator.

3. The method of any of Claims 1-2, wherein the RA resource types are one of subband full duplex, SBFD; or non-SBFD.

4. The method of any of Claims 2-3, wherein the indicator indicates a first priority of resources and a second priority of resources; and one of the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; and the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

5. The method of Claim 4, further comprising switching to the SBFD RA resources to continue the RA based on the UE (22) experiencing a failure for the contention-free RA procedure when using the non-SBFD RA resources.

6. The method of Claim 4, further comprising switching to the non-SBFD RA resources to continue the RA based on the UE (22) experiencing a failure for the contention-free RA procedure when using the SBFD RA resources.

7. The method of any of Claims 2-6, wherein the indicator is included in one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order signaled to the UE (22).

8. The method of Claim 7, wherein the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel, PRACH, preamble and a random access channel, RACH, occasion.

9. The method of Claim 7, further comprising, when a contention-free RA event associated with the dedicated RA configuration is triggered, performing the contention-free RA procedure using the RA resources as indicated by the RA resource type in the dedicated RA configuration.

10. A user equipment, UE, (22) configured to communicate with a network node (16), the UE (22) configured to: receive control signaling from the network node (16); select between random access, RA, resource types for a contention-free RA procedure based on the received control signaling; and perform the contention-free RA procedure based on the selection.

11. The UE (22) of Claim 10, wherein the control signaling includes an indicator indicating the RA resource type for the contention-free RA procedure, the selection between the RA resource types for the contention-free RA procedure being based on the indicator.

12. The UE (22) of any one of Claims 10-11, wherein the RA resource types are one of: subband full duplex, SBFD; or non-SBFD.

13. The UE (22) of any one of Claims 10-12, wherein the indicator indicates a first priority of resources and a second priority of resources; andone of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; and the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

14. The UE (22) of Claim 13, wherein the UE (22) is further configured to switch to the SBFD RA resources to continue the RA based on the UE (22) experiencing a failure for the contention-free RA procedure when using the non-SBFD RA resources.

15. The UE (22) of Claim 13, wherein the UE (22) is further configured to switch to the non-SBFD RA resources to continue the RA based on the UE (22) experiencing a failure for the contention-free RA procedure when using the SBFD RA resources.

16. The UE (22) of any one of Claims 11-15, wherein the indicator is included in one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order signaled to the UE (22).

17. The UE (22) of Claim 16, wherein the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel, PRACH, preamble and a random access channel, RACH, occasion.

18. The UE (22) of Claim 16, wherein the UE (22) is further configured to, when a contention-free RA event associated with the dedicated RA configuration is triggered, perform the contention-free RA procedure using the RA resources as indicated by the RA resource type in the dedicated RA configuration.

19. A method implemented in a network node (16) that is configured to communicate with a user equipment, UE (22), the method comprising: transmitting (SI 00) control signaling to the UE (22) for selection between random access, RA, resource types for a contention-free RA procedure based on the control signaling; andreceiving (SI 02) contention free RA signaling from the UE (22) based on the UE (22) selection.

20. The method of Claim 19, further comprising including an indicator in the control signaling, the indicator indicating the RA resource type for the contention-free RA procedure for selecting between the RA resource types for the contention-free RA procedure based on the indicator.

21. The method of any one of Claims 19-20, wherein the RA resource types are one of: subband full duplex (SBFD); or non-SBFD.

22. The method of any one of Claims 19-21, wherein the indicator indicates a first priority of resources and a second priority of resources; and one of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; or the first priority of resources is SBFD RA resources and the second priority of resources is non-SBFD RA resources.

23. The method of any one of Claims 19-22, wherein the indicator is one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order.

24. The method of Claim 23, wherein the dedicated RA configuration includes the indicator indicating the RA resource type for the contention-free RA procedure, the indicated RA resources comprising one or both of a physical random access channel, PRACH, preamble and a random access channel, RACH, occasion.

25. The method of any of Claims 21-24, wherein the RA resource type is determined based on whether all neighboring cells are cells supporting SBFD RA.

26. The method of any of Claims 19-25, further comprising determining whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell supports SBFD operation.

27. The method of any of Claims 19-25, further comprising determining whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell is SBFD RA operation enabled.

28. The method of any of Claims 19-27, further comprising indicating in a handover request, whether the UE (22) prefers to have an SBFD RA capable / enabled cell as a target cell.

29. A network node (16) configured to communicate with a user equipment, UE, (22) the network node (16) configured to: transmit control signaling to the UE (22) for selection between random access, RA, resource types for a contention-free RA procedure based on the control signaling; and receive contention free RA signaling from the UE (22) based on the UE (22) selection.

30. The network node (16) of Claim 29, wherein the network node (16) is further configured to include an indicator in the control signaling, the indicator indicating the RA resource type for the contention-free RA procedure for selecting between the RA resource types for the contention-free RA procedure based on the indicator.

31. The network node (16) of any one of Claims 29-30, wherein the RA resource types are one of: subband full duplex (SBFD); or non- SBFD.

32. The network node (16) of any one of Claims 29-31, wherein the indicator indicates a first priority of resources and a second priority of resources; and one of: the first priority of resources is non-SBFD RA resources and the second priority of resources is SBFD RA resources; orthe first priority of resources is SBFD RA resources and the second priority of resources is non- SBFD RA resources.

33. The network node (16) of any one of Claims 29-32, wherein the indicator is one of a dedicated RA configuration and a physical downlink control channel, PDCCH, order.

34. The network node (16) of Claim 33, wherein the dedicated RA configuration includes the indicator indicating the RA resource type for the contention- free RA procedure, the indicated RA resources comprising one or both of a physical random access channel, PRACH, preamble and a random access channel, RACH, occasion.

35. The network node (16) of any of Claims 31-34, wherein the RA resource type is determined based on whether all neighboring cells are cells supporting SBFD RA.

36. The network node (16) of any of Claims 29-35, wherein the network node (16) is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell supports SBFD operation.

37. The network node (16) of any of Claims 29-35, wherein the network node (16) is further configured to determine whether a neighbor cell is a handover target cell candidate based on whether the neighbor cell is SBFD RA operation enabled.

38. The network node (16) of any of Claims 29-37, wherein the network node (16) is further configured to indicate in a handover request, whether the UE (22) prefers to have an SBFD RA capable / enabled cell as a target cell.

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