METHOD OF PRIORITIZING RANDOM ACCESS FOR MULTIMEDIA PRIORITY AND MISSION CRITICAL SERVICES AND APPARATUS THEREOF

Abstract

A communication method and system for converging a 5.sup.th generation (5G) communication system for supporting higher data rates beyond a 4.sup.th generation (4G) system with a technology for Internet of things (IoT) are provided. The communication method and system includes intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The method includes receiving and selectively applying at least one of a first set of random access prioritization parameters, a second set of random access prioritization parameters, or a third set of random access prioritization parameters, based on whether a random access procedure is initiated for beam failure recovery or handover.

Claims

1. A method performed by a terminal for random access in a wireless communication system, the method comprising: receiving, from a base station, at least one of a random access prioritization parameter for an access identity associated with an uplink bandwidth part (BWP), configuration of a special cell (spcell), or a random access prioritization parameter associated with a beam failure recovery; identifying that the random access prioritization parameter associated with the beam failure recovery is configured, in case that a random access procedure is initiated for the beam failure recovery; identifying whether the random access prioritization parameter for the access identity is configured, based on the random access prioritization parameter associated with the beam failure recovery being not configured; identifying whether the access identity for the terminal is configured to 1 or 2, and whether at least one bit corresponding to the access identity is set to one; and applying the random access prioritization parameter for the access identity during the random access procedure, in case that the random access prioritization parameter for the access identity is configured, the access identity for the terminal is configured to 1 or 2, and the at least one bit corresponding to the access identity is set to one.

2. The method of claim 1, further comprising: receiving, from the base station, a random access prioritization parameter associated with a handover, wherein the random access prioritization parameter associated with the handover is received based on a random access dedicated configuration for a selected carrier.

3. The method of claim 1, wherein the random access prioritization parameter for the access identity for a selected carrier is received based on a system information block 1 (SIB1), and wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of the selected carrier.

4. The method of claim 1, wherein whether the random access prioritization parameter for the access identity being configured is identified, in case that the random access procedure is not initiated for a handover and the beam failure recovery.

5. The method of claim 1, wherein the random access prioritization parameter includes at least one of a power ramping step and a backoff scaling factor.

6. A method performed by a terminal for random access in a wireless communication system, the method comprising: receiving, from a base station, at least one of a random access prioritization parameter for an access identity associated with an uplink bandwidth part (BWP), configuration of a special cell (spcell), or a random access prioritization parameter associated with a handover; identifying that the random access prioritization parameter associated with the handover is configured, in case that a random access procedure is initiated for the handover; identifying whether the random access prioritization parameter for the access identity is configured, in case that the random access prioritization parameter associated with the handover is not configured; identifying whether the access identity for the terminal is configured to 1 or 2, and whether at least one bit corresponding to the access identity is set to one; and applying the random access prioritization parameter for the access identity during the random access procedure, in case that the random access prioritization parameter for the access identity is configured, the access identity for the terminal is configured to 1 or 2, and the at least one bit corresponding to the access identity is set to one.

7. The method of claim 6, further comprising: receiving, from the base station, a random access prioritization parameter associated with a beam failure recovery, wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of a selected carrier.

8. The method of claim 7, wherein the random access prioritization parameter for the access identity for a selected carrier is received based on a system information block 1 (SIB1), and wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of the selected carrier.

9. The method of claim 6, wherein the random access prioritization parameter includes at least one of a power ramping step and a backoff scaling factor.

10. A terminal in a wireless communication system, the terminal comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a base station via the transceiver, at least one of a random access prioritization parameter for an access identity associated with an uplink bandwidth part (BWP), configuration of a special cell (spcell), or a random access prioritization parameter associated with a beam failure recovery, identify that the random access prioritization parameter associated with the beam failure recovery is configured, in case that a random access procedure is initiated for the beam failure recovery, identify whether the random access prioritization parameter for the access identity is configured, based on the random access prioritization parameter associated with the beam failure recovery being not configured, identify whether the access identity for the terminal is configured to 1 or 2, and whether at least one bit corresponding to the access identity is set to one, and apply the random access prioritization parameter for the access identity during the random access procedure, in case that the random access prioritization parameter for the access identity is configured, the access identity for the terminal is configured to 1 or 2, and the at least one bit corresponding to the access identity is set to one.

11. The terminal of claim 10, wherein the controller is further configured to receive, from the base station, a random access prioritization parameter associated with a handover, and wherein the random access prioritization parameter associated with the handover is received based on a random access dedicated configuration for a selected carrier.

12. The terminal of claim 10, wherein the random access prioritization parameter for the access identity for a selected carrier is received based on a system information block 1 (SIB1), and wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of the selected carrier.

13. The terminal of claim 10, wherein whether the random access prioritization parameter for the access identity being configured is identified, in case that the random access procedure is not initiated for a handover and the beam failure recovery.

14. The terminal of claim 10, wherein the random access prioritization parameter includes at least one of a power ramping step and a backoff scaling factor.

15. A terminal in a wireless communication system, the terminal comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a base station via the transceiver, at least one of a random access prioritization parameter for an access identity associated with an uplink bandwidth part (BWP), configuration of a special cell (spcell), or a random access prioritization parameter associated with a handover, identify that the random access prioritization parameter associated with the handover is configured, in case that a random access procedure is initiated for the handover, identify whether the random access prioritization parameter for the access identity is configured, in case that the random access prioritization parameter associated with the handover is not configured, identify whether the access identity for the terminal is configured to 1 or 2, and whether at least one bit corresponding to the access identity is set to one, and apply the random access prioritization parameter for the access identity during the random access procedure, in case that the random access prioritization parameter for the access identity is configured, the access identity for the terminal is configured to 1 or 2, and the at least one bit corresponding to the access identity is set to one.

16. The terminal of claim 15, wherein the controller is further configured to receive, from the base station, a random access prioritization parameter associated with a beam failure recovery, and wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of a selected carrier.

17. The terminal of claim 16, wherein the random access prioritization parameter for the access identity for a selected carrier is received based on a system information block 1 (SIB1), and wherein the random access prioritization parameter associated with the beam failure recovery is received based on a beam failure recovery configuration for an active UL BWP of the selected carrier.

18. The terminal of claim 15, wherein the random access prioritization parameters includes at least one of a power ramping step and a backoff scaling factor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0049] FIGS. 1A and 1B are flowcharts that illustrate an operation for determining random access channel (RACH) parameters to be applied for a random access (RA) procedure according to various embodiments of the disclosure;

[0050] FIG. 2 illustrates support by a next generation (NG)-radio access network (RAN) architecture of a PC5 interface according to an embodiment of the disclosure;

[0051] FIG. 3 is a flowchart that illustrates an example operation of a transmitter user equipment (UE) according to an embodiment of the disclosure;

[0052] FIG. 4 is a block diagram of a terminal according to an embodiment of the disclosure; and

[0053] FIG. 5 is a block diagram of a base station according to an embodiment of the disclosure.

[0054] Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.

DETAILED DESCRIPTION

[0055] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0056] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only, and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

[0057] It is to be understood that the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a component surface includes reference to one or more of such surfaces.

[0058] By the term substantially it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect that the characteristic was intended to provide.

[0059] It is known to those skilled in the art that blocks of a flowchart (or sequence diagram) and a combination of flowcharts may be represented and executed by non-transitory computer program instructions. These computer program instructions may be loaded on a processor of a general purpose computer, special-purpose computer, or programmable data processing equipment. When the loaded program instructions are executed by the processor, they create a means for carrying out functions described in the flowchart. Because the computer program instructions may be stored in a computer readable memory that is usable in a specialized computer or a programmable data processing equipment, it is also possible to create articles of manufacture that carry out functions described in the flowchart. Because the computer program instructions may be loaded on a computer or a programmable data processing equipment, when executed as processes, they may carry out operations of functions described in the flowchart.

[0060] A block of a flowchart may correspond to a module, a segment, or a code containing one or more executable instructions implementing one or more logical functions, or may correspond to a part thereof. In some cases, functions described by blocks may be executed in an order different from the listed order. For example, two blocks listed in sequence may be executed at the same time or executed in reverse order.

[0061] In this description, the words unit, module, or the like may refer to a software component or hardware component, such as, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC) capable of carrying out a function or an operation. However, a unit, or the like, is not limited to hardware or software. A unit, or the like, may be configured so as to reside in an addressable storage medium or to drive one or more processors. Units, or the like, may also refer to software components, object-oriented software components, class components, task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays or variables. A function provided by a component and unit may be a combination of smaller components and units, and may be combined with others to compose larger components and units. Components and units may be configured to drive a device or one or more processors in a secure multimedia card.

[0062] Prior to providing the detailed description, terms or definitions necessary to understand the disclosure are described. However, these terms should be construed in a non-limiting way.

[0063] A base station (BS) is an entity communicating with a user equipment (UE) and may be referred to as a BS, a base transceiver station (BTS), a node B (NB), an evolved NB (eNB), an access point (AP), a fifth generation (5G) NB (5GNB), or a next generation NB (gNB).

[0064] A UE is an entity communicating with a BS and may be referred to as a UE, a device, a mobile station (MS), a mobile equipment (ME), or a terminal.

Random Access Channel (RACH) Prioritization for Multimedia Prioritized Services (MPS) and Mission Critical Services (MCS)

RACH Prioritization Parameter Set 1

[0065] In this case, a UE receives system information block 1 (SIB1) from a gNB. The SIB1 includes initial uplink (UL) bandwidth part (BWP) configuration. The UE receives a radio resource control (RRC) reconfiguration message from the gNB. The RRC reconfiguration message includes initial UL BWP configuration.

[0066] Initial UL BWP configuration includes RACH configuration. This RACH configuration for initial UL BWP optionally includes a ra-Prioritization ForAccessIdentity information element (IE). The ra-PrioritizationForAccessIdentity IE includes RACH prioritization parameters (i.e., ra-Prioritization-r16) for MPS and/or MCS. The ra-PrioritizationForAccessIdentity IE also includes ra-PrioritizationForAl which indicates whether the RACH prioritization parameters indicated by ra-Prioritization-r16 can be applied for MPS only or MCS only or can be applied to both. The first/leftmost bit of ra-Prioritization ForAl corresponds to Access Identity 1 (i.e., MPS), and the next bit corresponds to Access Identity 2 (i.e., MCS). Value 1 indicates that the field ra-Prioritization-r16 applies; otherwise, the field does not apply. For example, if first/leftmost bit of ra-PrioritizationForAl is set to 1, then RACH prioritization parameters indicated by ra-Prioritization-r16 applies to MPS; if first/leftmost bit of ra-Prioritization ForAl is set to 0, then RACH prioritization parameters indicated by ra-Prioritization-r16 does not apply to MPS; if next bit of ra-PrioritizationForAl is set to 1, then RACH prioritization parameters indicated by ra-Prioritization-r16 applies to MCS; if next bit of ra-PrioritizationForAl is set to 0, then RACH prioritization parameters indicated by ra-Prioritization-r16 does not apply to MCS. The abstract syntax notation (ASN.1) structure for ra-PrioritizationForAccessIdentity IE is as follows:

TABLE-US-00001 ra-PrioritizationForAccessIdentity SEQUENCE { ra-Prioritization-r16 RA-Prioritization, ra-PrioritizationForAI-r16 BIT STRING (SIZE (2)) } RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

[0067] In an embodiment, RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE signaled in initial UL BWP configuration of an UL carrier (i.e., supplementary UL (SUL) or normal UL (NUL)) is applicable for RACH prioritization on any UL BWP of that UL carrier. The advantage of this approach is that the ra-PrioritizationForAccessIdentity IE is not signaled in configuration of every UL BWP, and thus reduces the overhead. In an embodiment, RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE is applied only for special cell (SpCell) (i.e., RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE signaled in initial UL BWP configuration of an UL carrier (i.e., SUL or NUL) of SpCell is applicable for RACH prioritization on any UL BWP of that UL carrier of SpCell). In an embodiment, RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE is applied for any cell of a cell group (i.e., RACH prioritization parameters included in the ra-Prioritization ForAccessIdentity IE signaled in initial UL BWP configuration of an UL carrier (i.e., SUL or NUL) of SpCell is applicable for RACH prioritization on any UL BWP of that UL carrier of any cell of a cell group associated with the SpCell).

[0068] In another embodiment, RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE signaled in initial UL BWP configuration of an UL carrier (i.e., SUL or NUL) is applicable for RACH prioritization on initial UL BWP of that UL carrier. In this case, the ra-PrioritizationForAccessIdentity IE signaled in UL BWP configuration of a UL BWP of an UL carrier (i.e., SUL or NUL) is applicable for RACH prioritization on that UL BWP of that UL carrier. The advantage of this approach is that the network has flexibility in determining whether to support RACH prioritization for MPS/MCS on an UL BWP. However, this leads to increased signaling overhead. In an embodiment, RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE is applied only for the SpCell (i.e., RACH prioritization parameters included in the ra-PrioritizationForAccessIdentity IE signaled in UL BWP configuration of an UL carrier (i.e., SUL or NUL) of the SpCell is applicable for RACH prioritization on that UL BWP of that UL carrier of the SpCell).

[0069] In an embodiment, ra-Prioritization parameters can be independently configured for MPS and MCS. ra-PrioritizationForAccessIdentityMPS indicates ra-Prioritization parameters for MPS. ra-PrioritizationForAccessIdentityMCS indicates ra-Prioritization parameters for MCS. The configuration can be provided only in initial UL BWP or can be BWP specific as follows.

TABLE-US-00002 ra-PrioritizationForAccessIdentityMPS SEQUENCE { ra-Prioritization-r16 RA-Prioritization, } ra-PrioritizationForAccessIdentityMCS SEQUENCE { ra-Prioritization-r16 RA-Prioritization, }

RACH Prioritization Parameter Set 2

[0070] In this case, a UE receives an RRC reconfiguration message from a gNB. The RRC reconfiguration message includes UL BWP configuration for one or more UL BWPs. UL BWP configuration optionally includes beam failure recovery (BFR) configuration. This BFR configuration optionally includes RACH prioritization parameters (i.e., ra-Prioritization). RACH prioritization parameters in BFR configuration are specific to UL BWP of that configuration. The ASN.1 structure for ra-Prioritization is as follows:

TABLE-US-00003 ra-Prioritization RA-Prioritization RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

RACH Prioritization Parameter Set 3

[0071] In this case, a UE receives an RRC reconfiguration message from a gNB. The RRC reconfiguration message includes Reconfiguration WithSync IE. Reconfiguration WithSync IE includes rach-ConfigDedicated IE. rach-ConfigDedicated IE optionally includes RACH prioritization parameters (i.e., ra-Prioritization) for SUL or NUL. The parameters indicated by rach-ConfigDedicated are applied only for UL BWP indicated by firstActiveUplinkBWP. The ASN.1 structure for ra-Prioritization is as follows:

TABLE-US-00004 ra-Prioritization RA-Prioritization RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

Selection of RACH Prioritization Parameters

[0072] When the RA procedure is initiated on a serving cell, the MAC entity (i.e., UE) first selects the UL carrier (SUL or NUL) of that serving Cell. If the carrier to use for the RA procedure is explicitly signaled (e.g., in an RRC reconfiguration message) by a gNB, the UE selects the signaled carrier for performing RA procedure. If the carrier to use for the RA procedure is not explicitly signaled; and if the serving cell for the RA procedure is configured with SUL); and if the reference signal received power (RSRP) of the downlink (DL) pathloss reference is less than rsrp-ThresholdSSB-SUL: the UE selects the SUL carrier for performing RA procedure. Otherwise, the UE selects the NUL carrier for performing RA procedure.

[0073] The UE then selects the UL and DL BWP for RA procedure on the selected UL carrier of a serving cell on which RA procedure is initiated as follows:

[0074] If PRACH occasions are not configured for the active UL BWP, the UE switches the active UL BWP to BWP indicated by initialUplinkBWP; and if the serving cell is a SpCell, the UE switches the active DL BWP to BWP indicated by initialDownlinkBWP.

[0075] Else if the serving cell is a SpCell and the active DL BWP does not have the same bwp-Id as the active UL BWP, the UE switches the active DL BWP to the DL BWP with the same bwp-Id as the active UL BWP.

[0076] The UE then determines whether to perform 2-step or 4-step RA for this RA procedure.

[0077] If this RA procedure is initiated by physical downlink control channel (PDCCH) order and if the ra-PreambleIndex explicitly provided by PDCCH is not 0b000000; or if the RA procedure is initiated for system information (SI) request and the RA resources for SI request have been explicitly provided by RRC; or if the RA procedure is initiated for BFR and if the CFRA resources for BFR request for 4-step RA procedure have been explicitly provided by RRC for the BWP selected for RA procedure; or if the RA procedure is initiated for reconfiguration with synchronization and if the CFRA resources for 4-step RA procedure have been explicitly provided in rach-ConfigDedicated for the BWP selected for RA, the UE selects 4-step RA procedure.

[0078] Else if the BWP selected for RA procedure is configured with both 2-step and 4-step RA resources and the RSRP of the DL pathloss reference is above RSRP_THRESHOLD_RA_TYPE_SELECTION (i.e., msgA-RSRP-ThresholdSUL if UL carrier is SUL or msgA-RSRP-Threshold if UL carrier is NUL); or if the BWP selected for RA procedure is only configured with 2-step RA resources (i.e., no 4-step RA resources configured); or if the RA procedure is initiated for reconfiguration with synchronization and if the CFRA resources for 2-step RA have been explicitly provided in rach-ConfigDedicated for the BWP selected for RA: the UE selects 2-step RA procedure.

Else the UE Selects 4-Step RA Procedure.

[0079] The UE then determines RACH prioritization parameters to be applied for this RA procedure.

[0080] FIGS. 1A and 1B are flowcharts that illustrate an operation for determining RACH prioritization parameters to be applied for an RA procedure according to various embodiments of the disclosure.

[0081] Referring to FIG. 1A, if an RA procedure is initiated on a serving cell at operation 105, a UE selects the UL carrier, UL/DL BWP and RA type at operation 110.

[0082] If RA type selected is 4-step RA, the UE identifies whether the RA procedure is initiated for handover at operation 115. If this RA procedure is initiated for handover, the UE identifies whether RACH prioritization parameters (i.e., ra-Prioritization) are configured in rach-ConfigDedicated for the selected carrier at operation 120.

[0083] If rach-ConfigDedicated is configured for the selected carrier (or for the active UL BWP of selected carrier) and ra-Prioritization is configured in the rach-ConfigDedicated, the UE applies these parameters for RACH prioritization at operation 125. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in rach-ConfigDedicated; otherwise, (i.e., if powerRampingStepHighPriority is not configured in the ra-Prioritization in rach-ConfigDedicated), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization in rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in rach-ConfigDedicated; otherwise, (i.e., if scalingFactorBI is not configured in the ra-Prioritization in rach-ConfigDedicated), the UE sets SCALING_FACTOR_BIto 1.

[0084] Else the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for the UE's access identity (i.e., in ra-PrioritizationForAccessIdentity) for the selected carrier at operation 130. If ra-PrioritizationForAccessIdentity is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by non-access stratum (NAS) to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForA1 is set to one: the UE applies these parameters for RACH prioritization at operation 135. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, (i.e., if powerRampingStepHighPriority is not configured in the ra-PrioritizationForAccessIdentity), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise (i.e., if scalingFactorBI is not configured in the ra-Prioritization ForAccessIdentity), the UE sets SCALING_FACTOR_BI to 1.

[0085] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at operation 140.

[0086] Referring to FIG. 1B, the UE identifies whether the RA procedure is initiated for BFR at operation 145. If the RA procedure is initiated for BFR, the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured in beamFailureRecoveryConfig for the selected carrier and UL BWP at operation 150.

[0087] If beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier and ra-Prioritization is configured in the beamFailureRecoveryConfig, the UE applies these parameters for RACH prioritization at operation 155. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in beamFailureRecoveryConfig; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization in beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-Prioritization in beamFailureRecoveryConfig; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0088] Else the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for UE's access identity (i.e., in ra-PrioritizationForAccessIdentity) for the selected carrier at operation 160. If ra-Prioritization ForAccessIdentity is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization at operation 165. For example, if powerRampingStepHighPriority, is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0089] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at operation 170.

[0090] Else (i.e., the RA procedure is initiated for reason other than handover and BFR) the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for UE's access identity (i.e., in ra-PrioritizationForAccessIdentity) for the selected carrier at operation 175. If ra-PrioritizationForAccessIdentity is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl set to one: the UE applies these parameters for RACH prioritization at operation 180. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0091] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at operation 185.

[0092] Referring again to FIG. 1A, if RA type selected is 2-step RA, the UE identifies whether the RA procedure is initiated for handover at the operation 115. If this RA procedure is initiated for handover, the UE identifies whether RACH prioritization parameters (i.e., ra-PrioritizationTwoStep) are configured in rach-ConfigDedicated for the selected carrier at the operation 120.

[0093] If rach-ConfigDedicated is configured for the selected carrier (or for the active UL BWP of selected carrier) and ra-PrioritizationTwoStep is configured in the rach-ConfigDedicated, the UE applies these parameters for RACH prioritization at the operation 125. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in rach-ConfigDedicated; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-PrioritizationTwoStep in rach-ConfigDedicated; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0094] Else the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for UE's access identity (i.e., in ra-Prioritization ForAccessIdentityTwoStep) for the selected carrier at the operation 130. If ra-Prioritization ForAccessIdentityTwoStep is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization at the operation 135. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0095] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at the operation 140.

[0096] Referring again to FIG. 1B, the UE identifies whether the RA procedure is initiated for BFR at the operation 145. If RA procedure is initiated for BFR, the UE identifies whether the RACH prioritization parameters (i.e., ra-PrioritizationTwoStep) are configured in beamFailureRecoveryConfig for the selected carrier and UL BWP at the operation 150.

[0097] If beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier and ra-PrioritizationTwoStep is configured in the beamFailureRecoveryConfig, the UE applies these parameters for RACH prioritization at the operation 155. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in beamFailureRecoveryConfig; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured the ra-PrioritizationTwoStep in in beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-PrioritizationTwoStep in beamFailureRecoveryConfig; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0098] Else the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for UE's access identity (i.e., in ra-Prioritization ForAccessIdentityTwoStep) for the selected carrier at the operation 160. If ra-Prioritization ForAccessIdentityTwoStep is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization at the operation 165. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0099] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at the operation 170.

[0100] Else (i.e., the RA procedure is initiated for reason other than handover and BFR) the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured for the UE's access identity (i.e., in ra-Prioritization ForAccessIdentityTwoStep) for the selected carrier at the operation 175. If ra-Prioritization ForAccessIdentityTwoStep is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization at the operation 180. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scaling FactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0101] Else the RA procedure is not prioritized, i.e., the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1 at the operation 185.

[0102] The UE may determine RACH prioritization parameters to be applied for the RA procedure based on another embodiment of the disclosure.

[0103] If RA type selected is 4-step RA, the UE identifies whether the RA procedure is initiated for handover. If this RA procedure is initiated for handover, the UE identifies whether RACH prioritization parameters (i.e., ra-Prioritization) are configured in rach-ConfigDedicated for the selected carrier.

[0104] If rach-ConfigDedicated is configured for the selected carrier and ra-Prioritization is configured in the rach-ConfigDedicated, the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the rach-ConfigDedicated; otherwise (i.e., if powerRampingStepHighPriority is not configured in the ra-Prioritization in the rach-ConfigDedicated), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in the rach-ConfigDedicated; otherwise (i.e., if scaling FactorBI is not configured in the ra-Prioritization in the rach-ConfigDedicated), the UE sets SCALING_FACTOR_BI to 1.

[0105] Else if ra-Prioritization ForAccessIdentity is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if is powerRampingStepHighPriority configured in the ra-Prioritization ForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise (i.e., if not configured in the ra-powerRampingStepHighPriority is Prioritization ForAccessIdentity), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise (i.e., if scalingFactorBI is not configured in the ra-Prioritization ForAccessIdentity), the UE sets SCALING_FACTOR_BI to 1.

[0106] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0107] Else if RA procedure is initiated for BFR, the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured in beamFailureRecoveryConfig for the active UL BWP of the selected carrier and UL BWP.

[0108] If beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier and ra-Prioritization is configured in the beamFailureRecoveryConfig, the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets

[0109] PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the beamFailureRecoveryConfig; otherwise (i.e., if powerRampingStepHighPriority is not configured in the ra-Prioritization in the beamFailureRecoveryConfig), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in the beamFailureRecoveryConfig; otherwise (i.e., if scalingFactorBI is not configured in the ra-Prioritization in the beamFailureRecoveryConfig), the UE sets SCALING_FACTOR_BI to 1.

[0110] Else if ra-Prioritization ForAccessIdentity is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the UE access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization ForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise (i.e., if powerRampingStepHighPriority is not configured in the ra-Prioritization ForAccessIdentity), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise (i.e., if scalingFactorBI is not configured in the ra-Prioritization ForAccessIdentity), the UE sets SCALING_FACTOR_BI to 1.

[0111] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0112] Else (i.e., RA procedure is initiated for reason other than handover and BFR) if ra-Prioritization ForAccessIdentity is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise (i.e., if powerRampingStepHighPriority is not configured in the ra-Prioritization ForAccessIdentity), the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise (i.e., if scalingFactorBI is not configured in the ra-Prioritization ForAccessIdentity), the UE sets SCALING_FACTOR_BI to 1.

[0113] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0114] If RA type selected is 2-step RA, the UE identifies whether the RA procedure is initiated for handover. If this RA procedure is initiated for handover, the UE identifies whether RACH prioritization parameters (i.e., ra-PrioritizationTwoStep) are configured in rach-ConfigDedicated for the selected carrier.

[0115] If rach-ConfigDedicated is configured for the selected carrier and ra-PrioritizationTwoStep is configured in the rach-ConfigDedicated, the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the rach-ConfigDedicated; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to If the powerRampingStep. scalingFactorBI is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-PrioritizationTwoStep in the rach-ConfigDedicated; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0116] Else if ra-PrioritizationForAccessIdentityTwoStep is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scaling FactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0117] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0118] Else if RA procedure is initiated for BFR, the UE identifies whether the RACH prioritization parameters (i.e., ra-Prioritization) are configured in beamFailureRecoveryConfig for the active UL BWP of the selected carrier and UL BWP.

[0119] If beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier and ra-PrioritizationTwoStep is configured in the beamFailureRecoveryConfig, the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0120] Else if ra-PrioritizationForAccessIdentityTwoStep is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the UE access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0121] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0122] Else (i.e., RA procedure is initiated for reason other than handover and BFR) if ra-Prioritization ForAccessIdentity is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority; otherwise, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI; otherwise, the UE sets SCALING_FACTOR_BI to 1.

[0123] Else the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStep and SCALING_FACTOR_BI to 1.

[0124] The UE may determine RACH prioritization parameters to be applied for the RA procedure based on another embodiment of the disclosure.

[0125] If RA type selected is 4-step RA, the UE sets PREAMBLE_POWER_RAMPING_STEP to powerRampingStep and SCALING_FACTOR_BI to 1.

[0126] If ra-PrioritizationForAccessIdentity is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scaling FactorBI.

[0127] If this RA is initiated for handover; and if rach-ConfigDedicated is configured for the selected carrier; and if ra-Prioritization is configured in the rach-ConfigDedicated: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the rach-ConfigDedicated. If scalingFactorBI is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-Prioritization in the rach-ConfigDedicated.

[0128] Else if the RA procedure is initiated for BFR; and if beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier; and if ra-Prioritization is configured in the beamFailureRecoveryConfig: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the beamFailureRecoveryConfig. If scaling FactorBI is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in the beamFailureRecoveryConfig.

[0129] If RA type selected is 2-step RA, the UE sets PREAMBLE_POWER_RAMPING_STEP to powerRampingStep and SCALING_FACTOR_BI to 1.

[0130] If ra-PrioritizationForAccessIdentityTwoStep is configured for the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationForAccessIdentityTwoStep, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scaling FactorBI.

[0131] If this RA is initiated for handover; and if rach-ConfigDedicated is configured for the selected carrier; and if ra-PrioritizationTwoStep is configured in the rach-ConfigDedicated: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the rach-ConfigDedicated. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-PrioritizationTwoStep in the rach-ConfigDedicated.

[0132] Else if the RA procedure is initiated for BFR; and if beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier; and if ra-PrioritizationTwoStep is configured in the beamFailureRecoveryConfig: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig.

[0133] The UE may determine RACH prioritization parameters to be applied for the RA procedure based on another embodiment of the disclosure.

[0134] If RA type selected is 4-step RA, the UE sets PREAMBLE_POWER_RAMPING_STEP to powerRampingStep and SCALING_FACTOR_BI to 1.

[0135] If ra-PrioritizationForAccessldentity is configured for the active UL BWP of selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAI is set to one: the UE applies these parameters for RACH prioritization. For example, if configured powerRampingStepHighPriority is in the ra-Prioritization ForAccessIdentity, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority. If scalingFactorBI is configured in the ra-PrioritizationForAccessIdentity, the UE sets SCALING_FACTOR_BI to the scalingFactorBI.

[0136] If this RA procedure is initiated for handover; and if rach-ConfigDedicated is configured for the selected carrier; and if ra-Prioritization is configured in the rach-ConfigDedicated: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the rach-ConfigDedicated. If scalingFactorBI is configured in the ra-Prioritization in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in the rach-ConfigDedicated.

[0137] Else if the RA procedure is initiated for BFR; and if beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier; and if ra-Prioritization is configured in the beamFailureRecoveryConfig: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-Prioritization in the beamFailureRecoveryConfig. If scaling FactorBI is configured in the ra-Prioritization in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-Prioritization in the beamFailureRecoveryConfig.

[0138] If RA type selected is 2-step RA, the UE sets PREAMBLE_POWER_RAMPING_STEP to powerRampingStep and SCALING_FACTOR_BI to 1.

[0139] If ra-PrioritizationForAccessIdentityTwoStep is configured for the active UL BWP of the selected carrier; and if one or more access identities have been explicitly provided by RRC (i.e., the UE is configured with one or more access identities, and the access identity is provided by NAS to RRC); and if for at least one of these access identities, the corresponding bit in the ra-PrioritizationForAl is set to one: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-UE sets Prioritization ForAccessIdentityTwoStep, the PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority. If scalingFactorBI is configured in the ra-Prioritization ForAccessIdentityTwoStep, the UE sets SCALING_FACTOR_BI to the scaling FactorBI.

[0140] If this RA procedure is initiated for handover; and if rach-ConfigDedicated is configured for the selected carrier; and if ra-PrioritizationTwoStep is configured in the rach-ConfigDedicated: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the rach-ConfigDedicated. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the ra-PrioritizationTwoStep in the rach-ConfigDedicated.

[0141] Else if the RA procedure is initiated for BFR; and if beamFailureRecoveryConfig is configured for the active UL BWP of the selected carrier; and if ra-PrioritizationTwoStep is configured in the beamFailureRecoveryConfig: the UE applies these parameters for RACH prioritization. For example, if powerRampingStepHighPriority is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig. If scalingFactorBI is configured in the ra-PrioritizationTwoStep in the beamFailureRecoveryConfig, the UE sets SCALING_FACTOR_BI to the scaling FactorBI in the ra-PrioritizationTwoStep in the beamFailure RecoveryConfig.

[0142] The UE then selects RA resources according to selected RA type and transmits an RA preamble in case of 4-step RA or a MSGA (i.e., an RA preamble and a MSGA payload) in case of 2-step RA.

[0143] If an RA attempt is not successful, before the next RA attempt based on CBRA, the UE performs backoff if a backoff index is received in an RAR/MSGB after transmitting the RA preamble/MSGA during the RA attempt of 4-step RA or 2-step RA respectively. The UE retransmits an RA preamble/MSGA after a time period which is randomly selected between 0 and SCALING_FACTOR_BI*backoff value, where SCALING_FACTOR_BI is determined as described above. The backoff value corresponding to the backoff index received in the RAR is obtained by the UE from a pre-defined backoff table.

[0144] If an RA attempt is not successful, during the next RA attempt, the UE uses PREAMBLE_POWER_RAMPING_STEP for power ramping (as in section 5.1.3 and 5.1.3a of technical specification (TS) 38.321) where PREAMBLE_POWER_RAMPING_STEP is determined as described above.

Handover and Usage of Various RACH Prioritization Parameters

[0145] The UE receives from a source SpCell an RRCReconfiguration message including Reconfig WithSync IE.

[0146] A first RACH prioritization parameter set is included in rach-ConfigDedicated IE of the received RRCReconfiguration message. The rach-ConfigDedicated IE includes RACH prioritization parameters (i.e., ra-Prioritization) for SUL or NUL. The parameters indicated by rach-ConfigDedicated are applied only for UL BWP indicated by firstActiveUplinkBWP. The ASN.1 structure for ra-Prioritization is as follows:

TABLE-US-00005 ra-Prioritization RA-Prioritization RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

[0147] A second RACH prioritization parameter set is included in beamFailureRecoveryConfig IE in the received RRCReconfiguration message. The received RRC reconfiguration message includes UL BWP configuration for one or more UL BWPs. UL BWP configuration includes BFR configuration (i.e., beamFailureRecoveryConfig IE). This BFR configuration includes RACH prioritization parameters (i.e., ra-Prioritization). RACH prioritization parameters in BFR configuration are specific to UL BWP of that configuration. The ASN.1 structure for ra-Prioritization is as follows:

TABLE-US-00006 ra-Prioritization RA-Prioritization RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

[0148] The UE initiates RA procedure and performs the RA procedure toward the target SpCell. During the RA procedure, the UE applies first RACH prioritization parameter set for RACH prioritization. For example, if powerRampingStepHighPriority the is configured in rach-ConfigDedicated, the UE sets PREAMBLE_POWER_RAMPING_STEP to the powerRampingStepHighPriority in the rach-ConfigDedicated. If scalingFactorBI is configured in the rach-ConfigDedicated, the UE sets SCALING_FACTOR_BI to the scalingFactorBI in the rach-ConfigDedicated.

[0149] The UE receives SIB1 in the target cell and acquires a third RACH prioritization parameter set in ra-PrioritizationForAccessIdentity. Alternately, the UE may receive SIB1 in the received RRCReconfiguration message from the source cell or the UE may receive the third RACH prioritization parameter set in the received RRCReconfiguration message from the source cell. The third RACH prioritization parameter set is configured using ra-PrioritizationForAccessIdentity IE. ra-PrioritizationForAccessIdentity IE includes RACH prioritization parameters (i.e., ra-Prioritization-r16) for MPS and/or MCS. ra-PrioritizationForAccessIdentity IE also includes ra-PrioritizationForAl which indicates whether the RACH prioritization parameters indicated by ra-Prioritization-r16 can be applied for MPS only or MCS only or can be applied to both. The first/leftmost bit of ra-PrioritizationForAl corresponds to Access Identity 1 (i.e., MPS), and the next bit corresponds to Access Identity 2 (i.e., MCS). Value 1 indicates that the field ra-Prioritization-r16 applies, otherwise, the field does not apply. For example, if the first/leftmost bit of ra-PrioritizationForAl is set to 1, then RACH prioritization parameters indicated by ra-Prioritization-r16 applies to MPS; if the first/leftmost bit of ra-PrioritizationForAl is set to 0, then RACH prioritization parameters indicated by ra-Prioritization-r16 do not apply to MPS; if the next bit of ra-PrioritizationForAl is set to 1, then RACH prioritization parameters indicated by ra-Prioritization-r16 applies to MCS; if the next bit of ra-PrioritizationForAl is set to 0, then RACH prioritization parameters indicated by ra-Prioritization-r16 do not apply to MCS. The ASN.1 structure for ra-PrioritizationForAccessIdentity IE is as follows:

TABLE-US-00007 ra-PrioritizationForAccessIdentity SEQUENCE { ra-Prioritization-r16 RA-Prioritization, ra-PrioritizationForAI-r16 BIT STRING (SIZE (2)) } RA-Prioritization ::= SEQUENCE { powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6}, scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ... }

[0150] After the completion of handover, at some point in time, RA is triggered on a serving cell. Note that there can be several serving cells in a cell group.

[0151] If the serving cell is a secondary cell (SCell), the UE performs an RA procedure without applying RACH prioritization.

[0152] If the serving cell is a primary cell (PCell), the UE selects between second and third RACH prioritization parameter sets.

[0153] If RA procedure is initiated for BFR, the UE selects the second RACH prioritization parameter set for RACH prioritization.

[0154] If RA procedure is not initiated for BFR and UE is configured with Access Identity 1 or 2 and third RACH prioritization parameter set is allowed for UE's access identity, the UE selects the third RACH prioritization parameter set for RACH prioritization.

Else the UE does not Apply RACH Prioritization.

[0155] The UE performs an RA procedure with the selected PRACH prioritization parameter.

Selecting Hybrid Automatic Repeat Request (HARQ) feedback mechanism for New Radio (NR) Vehicle to Everything (V2X) Group Communication

[0156] The 4.sup.th generation (4G) and 5.sup.th (5G) wireless communication systems support vehicular communication services. Vehicular communication services, represented by V2X services, can consist of the following four different types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). In 5G (also referred as NR or New Radio) wireless communication system, V2X communication is being enhanced to support enhanced V2X use cases, which are broadly arranged into four use case groups:

[0157] 1) Vehicle platooning enables the vehicles to dynamically form a platoon travelling together. All the vehicles in the platoon obtain information from the leading vehicle to manage this platoon. This information allows the vehicles to drive closer than normal in a coordinated manner, going in the same direction and travelling together.

[0158] 2) Extended sensors enable the exchange of raw or processed data gathered through local sensors or live video images among vehicles, roadside units, devices of pedestrians, and V2X application servers. The vehicles can increase the perception of their environment beyond what their own sensors can detect and have a more broad and holistic view of the local situation. High data rate is one of the key characteristics.

[0159] 3) Advanced driving enables semi-automated or full-automated driving. Each vehicle and/or roadside unit (RSU) shares its own perception data obtained from its local sensors with vehicles in proximity, and that allows vehicles to synchronize and coordinate their trajectories or maneuvers. Each vehicle also shares its driving intention with vehicles in proximity.

[0160] 4) Remote driving enables a remote driver or a V2X application to operate a remote vehicle for those passengers who cannot drive by themselves or remote vehicles located in dangerous environments. For a case where variation is limited and routes are predictable, such as public transportation, driving based on cloud computing can be used. High reliability and low latency are the main requirements.

[0161] V2X services can be provided by a PC5 interface and/or a Uu interface. Support of V2X services via PC5 interface is provided by NR sidelink (SL) communication or V2X SL communication, which is a mode of communication whereby UEs can communicate with each other directly over the PC5 interface using NR technology or evolved universal mobile telecommunications system (UMTS) terrestrial radio access (EUTRA) technology respectively without traversing any network node. This communication mode is supported when the UE is served by a radio access network (RAN) and when the UE is outside of RAN coverage. Only the UEs authorized to be used for V2X services can perform NR or V2X SL communication.

[0162] FIG. 2 illustrates support by a next generation (NG)-RAN architecture of a PC5 interface according to an embodiment of the disclosure.

[0163] Referring to FIG. 2, in a network of a number Xn of gNB and ng-eNB devices providing an NG-RAN coverage, SL transmission and reception over the PC5 interface are supported when a UE is inside NG-RAN coverage, irrespective of which RRC state the UE is in, and when the UE is outside NG-RAN coverage. Support of V2X services via the PC5 interface can be provided by NR SL communication and/or V2X SL communication. NR SL communication may be used to support services other than V2X services.

[0164] SL or PC5 interface also supports UE-to-UE direct communication using the SL resource allocation modes, physical-layer signals/channels, and physical layer procedures below.

[0165] Two SL resource allocation modes are supported: mode 1 and mode 2. In mode 1, the SL resource allocation is provided by the network. In mode 2, the UE decides the SL transmission resources in the resource pool(s).

[0166] Physical SL control channel (PSCCH) indicates resource and other transmission parameters used by a UE for physical SL shared channel (PSSCH). PSCCH transmission is associated with a demodulation reference signal (DM-RS). SL control information (1.sup.st stage SL control information (SCI)) is transmitted on PSCCH.

[0167] PSSCH transmits the transport blocks (TBs) of data themselves, control information for HARQ procedures, and channel state information (CSI) feedback triggers, etc. Control information is referred as 2.sup.nd stage SCI. At least 6 orthogonal frequency division multiplexing (OFDM) symbols within a slot are used for PSSCH transmission. PSSCH transmission is associated with a DM-RS and may be associated with a phase tracking reference signal (PT-RS).

[0168] Physical SL feedback channel (PSFCH) carries HARQ feedback over the SL from a UE which is an intended recipient of a PSSCH transmission to the UE which performed the transmission. PSFCH sequence is transmitted in one physical resource block (PRB) repeated over two OFDM symbols near the end of the SL resource in a slot.

[0169] The SL synchronization signal consists of SL primary and SL secondary synchronization signals (S-PSS, S-SSS), each occupying 2 symbols and 127 subcarriers. Physical SL broadcast channel (PSBCH) occupies 9 and 5 symbols for normal and extended cyclic prefix cases respectively, including the associated DM-RS.

[0170] SL HARQ feedback uses PSFCH and can be operated in one of two options. In one option, which can be configured for unicast and groupcast, PSFCH transmits either ACK or NACK using a resource dedicated to a single PSFCH transmitting UE. In another option, which can be configured for groupcast, PSFCH transmits NACK, or no PSFCH signal is transmitted, on a resource that can be shared by multiple PSFCH transmitting UEs.

[0171] For transmitting data over PC5 interface, transmitter UE first transmits 1 st stage SCI over PSCCH resource. 1.sup.st stage SCI includes information on the TB such as: priority, frequency resource assignment, time resource assignment, resource reservation period, DM-RS pattern, 2.sup.nd stage SCI format, modulation and coding scheme (MCS), number of DM-RS port, etc. Transmitter UE then transmits 2.sup.nd stage SCI over PSSCH. The second stage SCI includes information such as, HARQ process number, new data indicator (NDI), redundancy version (RV), source identifier (ID), destination ID, HARQ feedback enabled/disabled indicator, cast type, CSI request, zone ID, range, etc. Transmitter UE then transmits TB carrying SL MAC protocol data unit (PDU) over PSSCH.

[0172] There are two types of HARQ feedback options for NR V2X group communication as described below:

[0173] Group Communication HARQ Feedback Option 1 (GC Option 1, also referred as negative only acknowledgement)

[0174] In this option, if HARQ packet (i.e., TB) transmitted by the transmitter UE is successfully received by the receiver UE, the receiver UE does not send any HARQ feedback. If the HARQ packet (i.e., TB) is not successfully received by the receiver UE, the receiver UE sends HARQ NACK if the distance between the receiver UE and the transmitter UE is smaller than the communication range. The communication range and its location information are indicated by the transmitter UE in scheduling control information (i.e., 2.sup.nd stage SCI transmitted by the transmitter UE). Based on location information received from transmitter UE and its location information, the receiver UE calculates the distance.

[0175] Group Communication HARQ Feedback Option 2 (GC Option 2, also referred as positive-negative acknowledgement)

[0176] In this option, if the HARQ packet (i.e., TB) transmitted by the transmitter UE is successfully received by the receiver UE, the receiver UE sends HARQ ACK. If the HARQ packet (i.e., TB) is not successfully received by the receiver UE, the receiver UE sends HARQ NACK to the transmitter.

[0177] The transmitter UE selects the HARQ feedback option and indicates the same to the receiver UE in 2.sup.nd stage SCI. The issue is how the transmitter UE selects HARQ feedback option.

[0178] FIG. 3 is a flowchart that illustrates an example operation of a transmitter UE according to an embodiment of the disclosure.

[0179] In one embodiment of this disclosure, the selection criteria, i.e., criteria to select the HARQ feedback option can be as follows:

[0180] Transmitter UE generates TB for transmission over PC5 interface at operation 310. The TB is destined for a group of UEs (i.e., TB is for groupcast communication).

[0181] The transmitter UE then determines whether the number of PSFCH resources associated with SL grant for transmitting the TB is greater than or equal to a number of members in the group to which the TB is destined at operation 320.

[0182] In one embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is smaller than (i.e., not greater than or equal to) number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), transmitter UE selects GC Option 1 at operation 330. The transmitter UE indicates in SCI that HARQ feedback is enabled. It also indicates in SCI that HARQ feedback is only NACK. The transmitter UE identifies whether the transmitter UE has its location information at operation 340. If the transmitter UE has its location information in operation 340, it includes its location information and communication range in SCI at operation 350; otherwise, it does not include its location information and communication range in SCI at operation 360.

[0183] In another embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is smaller than (i.e., not greater than or equal to) number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), the transmitter UE further checks if it has its location information or not. If the transmitter UE has its location information, it selects GC Option 1, includes its location information and communication range in SCI, indicates in SCI that HARQ feedback is enabled, and indicates in SCI that HARQ feedback is only NACK. If the transmitter UE does not have its location information, it indicates in SCI that HARQ feedback is not enabled.

[0184] The transmitter UE then transmits the SCI and the TB.

[0185] In one embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is greater than or equal to number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), the transmitter UE can select either GC option 1 or GC option 2 at operation 370. The transmitter UE indicates in SCI that HARQ feedback is enabled.

[0186] In another embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is greater than or equal to a number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), the transmitter UE selects GC option 2, it indicates in SCI that HARQ feedback is enabled, indicates in SCI that HARQ feedback is ACK or NACK, and does not include location information and communication range in SCI.

[0187] In another embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is greater than or equal to a number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), the transmitter UE selects GC option 1. The transmitter UE indicates in SCI that HARQ feedback is enabled. It also indicates in SCI that HARQ feedback is only NACK. If the transmitter UE has its location information, it includes its location information and communication range in SCI; otherwise, it does not include its location information and communication range in SCI.

[0188] In another embodiment, if the number of PSFCH resources associated with SL grant for transmitting the TB (the number of PSFCH resources for a TB can be known from resource pool configuration) is greater than or equal to a number of members in the group to which the TB is destined (i.e., group whose MAC SDU(s) are scheduled in the TB), the transmitter UE further checks whether it has its location information or not. If the transmitter UE has its location information, it selects GC option 1, includes its location information and communication range in SCI, indicates in SCI that HARQ feedback is enabled, and indicates in SCI that HARQ feedback is only NACK. If the transmitter UE does not have its location information, it selects GC option 2, indicates in SCI that HARQ feedback is enabled, and indicates in SCI that HARQ feedback is ACK or NACK.

[0189] A receiver UE receives SCI and decodes the scheduled TB transmitted by the transmitter UE. Received SCI indicates that HARQ feedback is enabled. If the received SCI indicates that HARQ feedback is NACK only, operation at receiver UE is as follows:

[0190] In an embodiment, if the transmitter UE's location and communication range information is not included in the received SCI and the TB is not successfully decoded, the receiver UE transmits HARQ NACK. Note that in this case, the receiver UE does not check for its distance with the transmitter UE.

[0191] In an embodiment, if the transmitter UE's location and communication range information is included in the received SCI; and if the receiver UE's location information is not available; and if the TB is not successfully decoded: the receiver UE transmits HARQ NACK. Note that in this case, the receiver UE does not check for its distance with the transmitter UE even if the transmitter UE's location and communication range information is included in the received SCI.

[0192] In an embodiment, if the transmitter UE's location and communication range information is included in the received SCI; and if the receiver UE's location information is not available; and if the TB is not successfully decoded: the receiver UE does not transmit HARQ NACK.

[0193] In an embodiment, if the transmitter UE's location and communication range information is included in the received SCI; and if the receiver UE's location information is not available; and if the TB is not successfully decoded; and if a skip HARQ feedback indication received from network (e.g., in an RRC message, DCI, or an SL resource configuration) is set to 1: the receiver UE does not transmit HARQ NACK.

[0194] In an embodiment, if the transmitter UE's location and communication range information is included in the received SCI; and if the receiver UE's location information is not available; and if the TB is not successfully decoded; and if a skip HARQ feedback indication is set to 0 or is not included/configured: the receiver UE transmits HARQ NACK.

[0195] FIG. 4 is a block diagram of a terminal according to an embodiment of the disclosure.

[0196] Referring to FIG. 4, a terminal includes a transceiver 410, a controller 420 and a memory 430. The controller 420 may refer to a circuitry, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or at least one processor. The transceiver 410, the controller 420, and the memory 430 are configured to perform the operations of the UE illustrated elsewhere in the figures, e.g., FIGS. 1A, 1B, 2, and 3, or as otherwise described above. Although the transceiver 410, the controller 420, and the memory 430 are shown as separate entities, they may be integrated onto a single chip. The transceiver 410, the controller 420, and the memory 430 may also be electrically connected to or coupled with each other.

[0197] The transceiver 410 may transmit and receive signals to and from other network entities, e.g., a base station or another terminal.

[0198] The controller 420 may control the UE to perform functions according to the embodiments described above. For example, the controller 420 may be configured to control the transceiver 410 to receive, from a gNB, ra-PrioritizationForAccessIdentity in an initial UL BWP configuration of an UL carrier (i.e., SUL or NUL) of SpCell. Prioritization ForAccessIdentity signaled in the initial UL BWP configuration of the UL carrier (i.e., SUL or NUL) of SpCell may be applicable for RACH prioritization on any UL BWP of that UL carrier of SpCell.

[0199] In addition, the controller 420 may be configured to select 4-step RA prioritization parameters for an RA procedure initiated for BFR. For example, if the RA procedure is initiated for BFR; and if 4-step RA prioritization parameters are not configured for BFR; and if the UE's access identity is 1 or 2; and if 4-step RA prioritization parameters are configured for the UE's access identity: the controller 420 may be configured to select 4-step RA prioritization parameters (e.g., powerRampingStepHighPriority, scalingFactorBI) configured for the UE's access identity. Else if the RA procedure is initiated for BFR; and if 4-step RA prioritization parameters are not configured for BFR; and if the UE's access identity is 1 or 2; and if 4-step RA prioritization parameters are not configured for the UE's access identity: the controller 420 may be configured to do not apply RA prioritization to this RA procedure, i.e., a backoff scaling factor is set to 1 and a power ramping step is applied from common configuration.

[0200] In addition, the controller 420 may be configured to select 4-step RA prioritization parameters for an MPS/MCS UE for an RA procedure initiated for handover. For example, if the RA procedure is initiated for handover; and if 4-step RA prioritization parameters are not configured for handover; and if the UE's access identity is 1 or 2; and if 4-step RA prioritization parameters are configured for the UE's access identity: the controller 420 may be configured to select 4-step RA prioritization parameters (e.g., powerRampingStepHighPriority, scalingFactorBI) configured for the UE's access identity. Else if the RA procedure is initiated for handover; and if 4-step RA prioritization parameters are not configured for handover; and if the UE's access identity is 1 or 2; and if 4-step RA prioritization parameters are not configured for the UE's access identity: the controller 420 may be configured to do not apply RA prioritization to this RA procedure, i.e., a backoff scaling factor is set to 1 and a power ramping step is applied from common configuration.

[0201] In addition, the controller 420 may be configured to select 2-step RA prioritization parameters for an MPS/MCS UE for an RA procedure initiated for BFR. For example, if the RA procedure is initiated for BFR; and if 2-step RA prioritization parameters are not configured for BFR; and if the UE's access identity is 1 or 2; and if 2-step RA prioritization parameters are configured for the UE's access identity: the controller 420 may configured to select 2-step RA prioritization parameters (e.g., powerRampingStepHighPriority, scalingFactorBI) configured for the UE's access identity. Else if the RA procedure is initiated for BFR; and if 2-step RA prioritization parameters are not configured for BFR; and if the UE's access identity is 1 or 2; and if 2-step RA prioritization parameters are not configured for the UE's access identity: the controller 420 may be configured to do not apply RA prioritization to this RA procedure, i.e., a backoff scaling factor is set to 1 and a power ramping step is applied from common configuration.

[0202] In addition, the controller 420 may be configured to select 2-step RA prioritization parameters for an MPS/MCS UE for an RA procedure initiated for handover. For example, if the RA procedure is initiated for handover; and if 2-step RA prioritization parameters are not configured for handover; and if the UE's access identity is 1 or 2; and if 2-step RA prioritization parameters are configured for the UE's access identity: the controller 420 may be configured to select 2-step RA prioritization parameters (e.g., powerRampingStepHighPriority, scalingFactorBI) configured for the UE's access identity. Else if the RA procedure is initiated for handover; and if 2-step RA prioritization parameters are not configured for handover; and if the UE's access identity is 1 or 2; and if 2-step RA prioritization parameters are not configured for the UE's access identity: the controller 420 may be configured to do not apply RA prioritization to this RA procedure, i.e., a backoff scaling factor is set to 1 and a power ramping step is applied from common configuration.

[0203] In addition, if SCI indicates negative only acknowledgement; and if a receiver UE does not have its location information; and if TB is not successfully received: the controller 420 of the receiver UE may be configured to control the transceiver 410 to transmit an HARQ NACK without checking its distance from a transmitter UE. Else if the receiver UE has its location information and TB is not successfully received, the controller 420 of the receiver UE may be configured to determine whether to transmit an HARQ NACK or not by checking its distance from the transmitter UE.

[0204] In addition, the controller 420 may be configured to select HARQ feedback mechanism for NR V2X group communication.

[0205] In an embodiment, the operations of the terminal may be implemented using the memory 430 storing corresponding program codes. Specifically, the terminal may be equipped with the memory 430 to store program codes implementing desired operations. To perform the desired operations, the controller 420 may read and execute the program codes stored in the memory 430 by using a processor or a central processing unit (CPU).

[0206] FIG. 5 is a block diagram of a base station according to an embodiment of the disclosure.

[0207] Referring to FIG. 5, a base station includes a transceiver 510, a controller 520, and a memory 530. The controller 520 may refer to a circuitry, an ASIC, an FPGA, or at least one processor. The transceiver 510, the controller 520, and the memory 530 are configured to perform the operations of the gNB illustrated elsewhere in the figures, e.g., FIGS. 1A, 1B, 2, and 3, or as otherwise described above. Although the transceiver 510, the controller 520, and the memory 530 are shown as separate entities, they may be integrated onto a single chip. The transceiver 510, the controller 520, and the memory 530 may also be electrically connected to or coupled with each other.

[0208] The transceiver 510 may transmit and receive signals to and from other network entities, e.g., a terminal.

[0209] The controller 520 may control the gNB to perform functions according to the embodiments described above. For example, the controller 520 may be configured to control the transceiver 510 to transmit, to a UE, ra-PrioritizationForAccessIdentity in an initial UL BWP configuration of an UL carrier (i.e., SUL or NUL) of SpCell. PrioritizationForAccessIdentity may be signaled in the initial UL BWP configuration of the UL carrier (i.e., SUL or NUL) of SpCell.

[0210] In an embodiment, the operations of the base station may be implemented using the memory 530 storing corresponding program codes. Specifically, the base station may be equipped with the memory 530 to store program codes implementing desired operations. To perform the desired operations, the controller 520 may read and execute the program codes stored in the memory 530 by using a processor or a CPU.

[0211] While the disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.