PUSCH Resource Selection in Two-Step Random Access

Abstract

Methods and apparatuses for PUSCH resource selection in 2-step random access (RA) are disclosed. In one embodiment, a wireless device is configured to receive a two-step RA configuration, which includes: a first resource allocation for PUSCH transmission of a first message msgA for a two-step RA procedure, the first resource allocation for PUSCH transmission of msgA being associated with a first set of preambles; a second resource allocation for PUSCH transmission of msgA associated with a second set of preambles; select one of the first and second resource allocations and one associated with the first and second sets of 10 preambles based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA; and use one of the first and second resource allocations selected to send the PUSCH transmission of msgA.

Description

Technical Field

[0001] The present disclosure relates to wireless communication, and more particularly to physical uplink shared channel (PUSCH) resource selection in two-step random access (RA). Background Art

[0002] RACH Configuration in NR

[0003] In the 3rd Generation Partnership Project (3GPP) New Radio (NR) (also known as "5G") standard, the random access (RA) procedure is described in the NR Media Access Control (MAC) specification, and the parameters are configured by Radio Resource Control (RRC), e.g., in system information or in handover (RRCReconfiguration with synchronous reconfiguration). Random access is triggered in many different scenarios, e.g., when a WD is in RRC_IDLE or RRC_INACTIVE and attempts to access the cell it is camped on (i.e., transition to RRC_CONNECTED).

[0004] In NR, the random access channel (RACH) configuration is broadcast in System Information Block 1 (SIB1) as part of the servingCellConfigCommon information element (IE) (with both downlink (DL) and uplink (UL) configurations), where the RACH configuration is within the uplinkConfigCommon IE. The exact RACH parameters are within the IE called initialUplinkBWP, as this is part of the UL frequency where the WD accesses and searches for RACH resources.

[0005] The RACH configuration parameters can be found in 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 38.331 (version 15.6.0), which mainly focuses on parameters related to the mapping of preambles and RACH resources / timings, and the preambles may also be mapped to PUSCH resources for MsgA transmission in two-step random access in future versions of this specification.

[0006] The following sections separately describe the 4-step RA and 2-step RA in NR Release 15 (Rel-15) and Release 16 (Rel-16), where in the 2-step RA, after the combined preamble and msgA physical uplink shared channel (PUSCH), there is a msgB physical downlink shared channel (PDSCH) transmission, as initially agreed to be applied in the 2-step RA.

[0007] 4-Step RA Procedure in NR

[0008] A four-step method is used for the NR Rel-15 random access procedure, for example, as Figure 1 shown. In this method, the WD detects the synchronization signal (SS) and decodes the broadcast system information. Then, the WD sends a physical random access channel (PRACH) preamble (Message 1 / msg1) on the uplink. The network node (e.g., gNB) replies with a RAR (random access response, Message 2 / msg2). Then, the WD sends the WD identity (Message 3 / msg3) on the PUSCH.

[0009] After receiving a timing advance (TA) command in the RAR, the WD sends the PUSCH (Message 3), thus allowing the PUSCH to be received with timing accuracy within the cyclic prefix (CP). Without this timing advance, a very large CP would be required to be able to demodulate and detect the PUSCH, unless the system is applied in a cell where the distance between the WD and the network node (e.g., eNB) is very small. Since NR will also support larger cells that require a timing advance to be provided to the WD, this four-step method is used for the random access procedure.

[0010] N R Rel-15 PRACH Configuration

[0011] In NR, the time and frequency resources on which the physical random access channel (PRACH) preamble is sent are defined as a PRACH occasion.

[0012] In the present disclosure, a PRACH occasion is also referred to as a RACH occasion or an RA occasion or simply as an RO. The RO used to send the preamble in a two-step RA is called a two-step RO, while the RO used to send the preamble in a four-step RA is called a four-step RO.

[0013] The time resources and preamble format for PRACH transmission are configured by a PRACH configuration index, which indicates the rows in the PRACH configuration tables specified in Tables 6.3.3.2-2, 6.3.3.2-3, and 6.3.3.2-4 of 3GPP TS 38.211 (Release 15.6.0) for frequency 1 (FR1) paired spectrum, FR1 unpaired spectrum, and frequency 2 (FR2) with unpaired spectrum, respectively.

[0014] Part of Table 6.3.3.2-3 for FR1 unpaired spectrum with PRACH preamble format 0 in 3GPP TS 38.211 (Release 15.6.0) includes the x value in Table 6.3.3.2-3 that indicates the PRACH configuration period in terms of the number of system frames. The y value in Table 6.3.3.2-3 indicates the system frames within each PRACH configuration period on which the PRACH occasion is configured. For example, if y is set to 0, it means the PRACH occasion is only configured in the first frame of each PRACH configuration period. The value in the "subframe number" column of Table 6.3.3.2-3 tells on which subframes the PRACH occasion is configured. The value in the "starting symbol" column of Table 6.3.3.2-3 is the symbol index.

[0015] In the case of time division duplex (TDD), the semi-statically configured DL part and / or the actually transmitted synchronization signal block (SSB) can overwrite and invalidate some of the time-domain PRACH occasions defined in the PRACH configuration table. More specifically, the PRACH occasions in the UL part are always valid, while the PRACH occasions within the X part are valid as long as they are not before or in conflict with the SSB in the RACH time slot and it is at least N symbols after the last symbol of the DL part and the SSB. Depending on the PRACH format and subcarrier spacing, N is 0 or 2.

[0016] In the frequency domain, NR supports multiple frequency-multiplexed PRACH occasions on the same time-domain PRACH occasion. This is mainly due to the support for analog beam scanning in NR, such that the PRACH occasions associated with an SSB are configured at the same time instance but at different frequency positions. The number of frequency-division multiplexed (FDMed) PRACH occasions in a time-domain PRACH occasion can be 1, 2, 4, or 8. Figure 2 An example of PRACH occasion configuration in NR is illustrated.

[0017] In NR Rel-15, there are up to 64 sequences that can be used as random access preambles for each PRACH occasion in each cell. The radio resource control (RRC) parameter totalNumberOfRA-Preambles determines how many of these 64 sequences are used as random access preambles for each PRACH occasion in each cell. The 64 sequences are configured by first including all available cyclic shifts of the root Zadoff-Chu sequence and then in ascending order of the root index until 64 preambles have been generated for the PRACH occasion.

[0018] Association between NR Rel-15 SSB and PRACH Occasions

[0019] NR Rel-15 supports one-to-one, one-to-many, and many-to-one associations between SSB and PRACH occasions. For example, as shown in Figure 3 and Figure 4 .

[0020] When the WD detects an optimal SSB beam, a preamble is selected for random access from the set of one or more preambles mapped to that SSB. Then, when the network node (e.g., gNB) detects the preamble, the optimal SSB beam for that WD is indirectly known, so that the optimal beam can be used to send signals to or receive signals from that WD.

[0021] The preambles associated with each SSB are configured by two RRC parameters in RACH-ConfigCommon: ssb-perRACH-OccasionAndCB-PreamblesPerSSB and totalNumberOfRA-Preambles.

[0022] The detailed mapping rules are specified in Section 8.1 of TS 38.213 (version 15.6.0) as follows:

[0023] "Through ssb-perRACH-OccasionAndCB-PreamblesPerSSB, the UE is provided with N SS / PBCH blocks associated with one PRACH occasion and R contention-based preambles for each SS / PBCH block of each valid PRACH occasion. If N < 1, one SS / PBCH block is mapped to 1 / N consecutive valid PRACH occasions, and R contention-based preambles with consecutive indices associated with the SS / PBCH block of each valid PRACH occasion start from preamble index 0. If N ≥ 1, R contention-based preambles with consecutive indices n (0 ≤ n ≤ N - 1) associated with the SS / PBCH block n of each valid PRACH occasion start from preamble index where is provided by totalNumberOfRA-Preambles and is an integer multiple of N."

[0024] In other words, the mapping between SSB and preamble is done by associating M preambles continuously to each SSB, where and as Figure 5 shown, the preambles can be in the following order:

[0025] - First, within a single PRACH occasion, in ascending order of preamble index.

[0026] - Secondly, for the PRACH occasions with frequency reuse, in ascending order of frequency resource index.

[0027] - Thirdly, in ascending order of time.

[0028] For each SSB, the associated preambles for each PRACH occasion are further divided into two sets of contention-based random access (CBRA) and contention-free random access (CFRA). The number of contention-based (CB) preambles for each SSB of each PRACH occasion is signaled by the RRC parameter #CB-preambles-per-SSB. The preamble indices for CBRA and CFRA are mapped continuously for one SSB in a PRACH occasion, as Figure 6 shown.

[0029] Rel-15 SSB Selection

[0030] In the 4-step random access procedure, the WD selects an SSB with a Synchronization Signal - Reference Signal Received Power (SS-RSRP) higher than rsrp-ThresholdSSB (if such an SSB is available). The selected SSB will be indicated to the network node (e.g., gNB) either by the selected preamble or by the PRACH occasion (RO). This indication will enable the network node (e.g., gNB) to select a suitable DL beam for RAR transmission. The selection of the SSB for contention-based random access is specified in Section 5.1.2 of TS38.321 (version 15.6.0):

[0031] "1> Otherwise (i.e., for contention-based random access preamble selection):

[0032] 2> If at least one SSB with an SS-RSRP higher than rsrp-ThresholdSSB is available:

[0033] 3> Select an SSB with an SS-RSRP higher than rsrp-ThresholdSSB.

[0034] 2> Otherwise:

[0035] 3> Select any SSB."

[0036] The preamble transmission (and the mapping of RO to SSB) is specified in the same section of the same document:

[0037] "1> Otherwise, if an SSB is selected as above:

[0038] 2> If configured or indicated by the PDCCH, determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB(s) permitted by the constraint given by ra-ssb-OccasionMaskIndex (according to Subclause 8.1 of TS 38.213 (Release 15.6.0), the MAC entity shall randomly select, with equal probability, a PRACH occasion among consecutive PRACH occasions corresponding to the selected SSB(s); when determining the next available PRACH occasion corresponding to the selected SSB(s), the MAC entity may take into account the possible occurrence of measurement gaps).”

[0039] Preamble Group Selection

[0040] In the 4-step random access procedure, the WD selects a random access preamble group based on the Msg3 size, logical channel, and path loss. This is based on the existing configuration of random access preamble group B and ra-Msg3SizeGroupA:

[0041] 2> If Msg3 has not been transmitted yet:

[0042] 3> If random access preamble group B is configured:

[0043] 4> If the potential Msg3 size (UL data available for transmission plus the MAC header and, if necessary, the MAC CE) is greater than ra-Msg3SizeGroupA and the path loss is less than PCMAX – preambleReceivedTargetPower – msg3-DeltaPreamble – messagePowerOffsetGroupB (of the serving cell where the random access procedure is performed); or

[0044] 4> If the random access procedure is initiated for the CCCH logical channel and the CCCH SDU size plus the MAC sub-header is greater than ra-Msg3SizeGroupA:

[0045] 5> Select random access preamble group B.

[0046] 4> Otherwise:

[0047] 5> Select random access preamble group A.

[0048] 3> Otherwise:

[0049] 4> Select random access preamble group A.

[0050] 2> Otherwise (i.e., Msg3 is being retransmitted):

[0051] 3> Select the same random access preamble group as the random access preamble transmission attempt corresponding to the first transmission of Msg3.

[0052] Where the parameters groupBconfigured (indicating whether random access preamble group B is configured) and ra-Msg3SizeGroupA are given in RACH-ConfigCommon, while preambleReceivedTargetPower is found in RACH-ConfigGeneric.

[0053] 2-Step RACH Work Item for Release 16 in 3GPP

[0054] The two-step RACH work item was approved at the 3GPP RAN1#82 plenary session.

[0055] The two-step RACH includes completing the initial access only in two steps, as Figure 7 shown and described below:

[0056] ● Step 1: The WD sends message A (msgA), which includes a random access preamble (sent on the PRACH) and higher layer data with a possible small payload on the PUSCH, such as an RRC connection request. The part of message A sent on the PUSCH is generally referred to as MsgA PUSCH or msgA PUSCH in this document.

[0057] ● Step 2: The network node (e.g., gNB) sends a response (referred to as message B or msgB), which includes, for example, one or more of WD identifier allocation, timing advance information, contention resolution message, backoff indication, and fallback command.

[0058] From Figure 8 the comparison of the four-step and two-step RAs shown in, one of the benefits of the two-step RA is the latency gain. Depending on the parameter set used in NR, the two-step process can result in approximately a 3-fold reduction compared to the four-step process. Summary of the Invention

[0059] Some embodiments advantageously provide methods and apparatuses for PUSCH resource selection in two-step random access (RA).

[0060] According to one aspect of the present disclosure, a method for selecting resources for a two-step random access (RA) procedure implemented in a wireless device is provided. The method includes receiving, from a network node, a two-step RA configuration for a cell, the two-step RA configuration including: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two-step RA procedure, the first resource allocation for PUSCH transmission of msgA being associated with a first preamble set; and a second resource allocation for PUSCH transmission of msgA associated with a second preamble set. The method includes: selecting one of the first and second resource allocations and an associated one of the first and second preamble sets based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA. The method includes using the selected one of the first and second resource allocations to send the PUSCH transmission of msgA.

[0061] In some embodiments of this aspect, the method further includes: selecting a preamble for msgA transmission for the two-step RA procedure from the selected one of the first and second preamble sets; and sending the selected preamble of msgA. In some embodiments of this aspect, selecting one of the first and second resource allocations and an associated one of the first and second preamble sets includes: comparing the payload size of the PUSCH transmission of msgA with a size threshold associated with the first and second resource allocations of the two-step RA configuration; when the payload size is greater than the size threshold, selecting the second resource allocation and the associated second preamble set; otherwise, selecting the first resource allocation and the associated first preamble set.

[0062] In some embodiments of this aspect, the two-step RA configuration further includes a path loss threshold associated with the second preamble set, and wherein selecting one of the first and second resource allocations and an associated one of the first and second preamble sets further includes: comparing the estimated downlink path loss with the path loss threshold associated with the second preamble set; and selecting the second resource allocation and the associated second preamble set only when the estimated downlink path loss is less than the path loss threshold. In some embodiments of this aspect, each of the first and second resource allocations includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version. In some embodiments of this aspect, selecting one of the first and second resource allocations is further based on the respective modulation and coding schemes of the first and second resource allocations. In some embodiments of this aspect, selecting one of the first and second resource allocations is further based on the respective transmit power instructions of the first and second resource allocations.

[0063] In some embodiments in this regard, the two-step RA configuration further includes transmit power thresholds associated with the first and second preamble sets, and selecting one of the first and second resource allocations and the associated one of the first and second preamble sets includes: estimating the transmit power of the PUSCH transmission for sending msgA on one of the first and second resource allocations; and selecting one of the first and second resource allocations based on whether the estimated transmit power meets the transmit power threshold. In some embodiments in this regard, selecting one of the first and second resource allocations and the associated one of the first and second preamble sets is further based on the logical channel for which the two-step RA process is performed. In some embodiments in this regard, selecting one of the first and second resource allocations is further based on whether the wireless device is an ultra-reliable low-latency communication URLLC device.

[0064] In some embodiments in this regard, the method further includes: selecting at least one beam from multiple beams in the cell; determining that the selected beam is associated with the two-step RA configuration; and using the two-step RA configuration associated with the selected beam to select one of the first and second resource allocations and the associated one of the first and second preamble sets. In some embodiments in this regard, selecting at least one beam further includes: selecting at least one beam from multiple beams in the cell based on a reference signal received power RSRP threshold, and the at least one selected beam includes at least one of the following: an SSB beam selected from multiple synchronization signal block SSB beams in the cell; and a CSI-RS beam selected from multiple channel state information reference signal CSI-RS beams in the cell.

[0065] In some embodiments in this regard, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to the selected at least one beam, the PUSCH configuration indicating the first and second resource allocations for the PUSCH transmission of msgA; a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being mapped to the PRACH configuration associated with the selected at least one beam; and a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being based on the logical channel for which the two-step RA process is performed.

[0066] In some embodiments of this aspect, at least one selected beam is mapped to multiple frequency - multiplexed random access channel (RACH) opportunities within a time resource. In some embodiments of this aspect, the size of a first resource allocation for PUSCH transmission for msgA is different from the size of a second resource allocation for PUSCH transmission for msgA. In some embodiments of this aspect, a two - step RA configuration is received in system information. In some embodiments of this aspect, the method further includes: determining a set of information bits for PUSCH transmission for msgA, the set of information bits corresponding to a payload; determining a transport block size based on at least one of a modulation and coding scheme, the number of orthogonal frequency - division multiplexing (OFDM) symbols, and the number of physical resource blocks indicated in one of the first and second resource allocations in the two - step RA configuration; when the set of information bits is less than or equal to the transport block size, sending a PUSCH transmission of msgA including the information bits; and when the set of information bits is greater than the transport block size, removing at least one bit from the set of information bits based on the priority of the logical channel for which the two - step RA process is performed.

[0067] According to another aspect of the present disclosure, a method implemented in a network node configured to communicate with a wireless device is provided. The method includes sending to the wireless device a two - step random access (RA) configuration for a cell, the two - step RA configuration including: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two - step RA process, the first resource allocation for PUSCH transmission of msgA being associated with a first set of preambles; and a second resource allocation for PUSCH transmission of msgA associated with a second set of preambles; and receiving a PUSCH transmission of msgA according to one of the first and second resource allocations, the one of the first and second resource allocations and the associated one of the first and second sets of preambles being based on the two - step RA configuration and the payload size of the PUSCH transmission of msgA.

[0068] In some embodiments of this aspect, the method further includes: receiving a preamble of a msgA transmission of the two - step RA process, the preamble being from one of a first set of preambles and a second set of preambles based on the two - step RA configuration and the payload size of the PUSCH transmission of msgA. In some embodiments of this aspect, the two - step RA configuration further includes a size threshold associated with the first and second resource allocations of the two - step RA configuration; and receiving a PUSCH transmission of msgA further includes: when the payload size is greater than the size threshold, receiving a PUSCH transmission of msgA according to the second resource allocation and the associated second set of preambles; otherwise, receiving a PUSCH transmission of msgA according to the first resource allocation and the associated first set of preambles.

[0069] In some embodiments in this regard, the two-step RA configuration further includes a path loss threshold associated with a second set of preambles; and receiving the PUSCH transmission of msgA further includes: receiving the PUSCH transmission of msgA according to the second resource allocation and the associated second set of preambles only when the estimated downlink path loss is less than the path loss threshold. In some embodiments in this regard, each of the first and second resource allocations includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version. In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the respective modulation and coding schemes of the first and second resource allocations.

[0070] In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the respective transmit power instructions of the first and second resource allocations. In some embodiments in this regard, the two-step RA configuration further includes a transmit power threshold associated with the first and second sets of preambles; and one of the first and second resource allocations for receiving the PUSCH transmission of msgA and one of the associated first and second sets of preambles are based on whether the estimated transmit power meets the transmit power threshold.

[0071] In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the logical channel for which the two-step RA process is performed. In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on whether the wireless device is an ultra-reliable low-latency communication (URLLC) device. In some embodiments in this regard, the PUSCH transmission of msgA is received according to the two-step RA configuration associated with at least one beam in the cell selected by the wireless device.

[0072] In some embodiments in this regard, the two-step RA configuration includes a reference signal received power (RSRP) threshold, and at least one beam in the cell is selected by the wireless device based on the RSRP threshold. In some embodiments in this regard, the at least one selected beam includes at least one of the following: an SSB beam selected from a plurality of synchronization signal block (SSB) beams in the cell; and a CSI-RS beam selected from a plurality of channel state information reference signal (CSI-RS) beams in the cell.

[0073] In some embodiments in this regard, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to at least one selected beam, the PUSCH configuration indicating first and second resource allocations for PUSCH transmission of msgA; a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with at least one selected beam; and a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being based on the logical channel for which the two-step RA procedure is performed.

[0074] In some embodiments in this regard, at least one selected beam is mapped to multiple frequency-multiplexed random access channel (RACH) opportunities in a time resource. In some embodiments in this regard, the size of the first resource allocation for PUSCH transmission of msgA is different from the size of the second resource allocation for PUSCH transmission of msgA. In some embodiments in this regard, the two-step RA configuration is sent in system information. In some embodiments in this regard, for each of the first and second resource allocations for PUSCH transmission of msgA, the two-step RA configuration indicates at least one of a modulation and coding scheme, the number of orthogonal frequency division multiplexing (OFDM) symbols, and the number of physical resource blocks.

[0075] According to another aspect of the present disclosure, a wireless device for selecting resources for a two-step random access (RA) procedure includes a processing circuit. The processing circuit is configured to cause the wireless device to receive, from a network node, a two-step RA configuration for a cell, the two-step RA configuration including: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two-step RA procedure, the first resource allocation for PUSCH transmission of msgA being associated with a first set of preambles; and a second resource allocation for PUSCH transmission of msgA associated with a second set of preambles. The processing circuit is configured to cause the wireless device to select one of the first and second resource allocations and one of the associated first and second sets of preambles based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA. The processing circuit is configured to cause the wireless device to use one of the first and second resource allocations that is selected to send the PUSCH transmission of msgA.

[0076] In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to: select a preamble for msgA transmission for the two-step RA procedure from one of a first and a second set of preambles; and transmit the selected preamble of msgA. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to select one of a first and a second resource allocation and an associated one of a first and a second set of preambles by being configured to cause the wireless device to perform the following: compare the payload size of the PUSCH transmission of msgA with a size threshold associated with the first and second resource allocations of the two-step RA configuration; when the payload size is greater than the size threshold, select the second resource allocation and the associated second set of preambles; otherwise, select the first resource allocation and the associated first set of preambles.

[0077] In some embodiments in this regard, the two-step RA configuration further includes a path loss threshold associated with the second set of preambles; and the processing circuitry is configured to cause the wireless device to select one of a first and a second resource allocation and an associated one of a first and a second set of preambles by being configured to cause the wireless device to perform the following: compare the estimated downlink path loss with the path loss threshold associated with the second set of preambles; and select the second resource allocation and the associated second set of preambles only when the estimated downlink path loss is less than the path loss threshold.

[0078] In some embodiments in this regard, each of the first and second resource allocations includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to further select one of the first and second resource allocations based on the respective modulation and coding schemes of the first and second resource allocations. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to further select one of the first and second resource allocations based on the respective transmit power instructions of the first and second resource allocations.

[0079] In some embodiments in this regard, the two-step RA configuration further includes transmit power thresholds associated with the first and second preamble sets; and the processing circuitry is configured to cause the wireless device to select one of the first and second resource allocations and an associated one of the first and second preamble sets by being configured to perform the following operations: estimate the transmit power of the PUSCH transmission for sending msgA on one of the first and second resource allocations; and select one of the first and second resource allocations based on whether the estimated transmit power meets the transmit power threshold. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to also select one of the first and second resource allocations and an associated one of the first and second preamble sets based on the logical channel for which the two-step RA procedure is performed. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to also select one of the first and second resource allocations based on whether the wireless device is an ultra-reliable low-latency communication URLLC device.

[0080] In some embodiments in this regard, the processing circuitry is further configured to cause the wireless device to: select at least one beam from multiple beams in the cell; determine that the selected beam is associated with the two-step RA configuration; and use the two-step RA configuration associated with the selected beam to select one of the first and second resource allocations and an associated one of the first and second preamble sets. In some embodiments in this regard, the processing circuitry is configured to cause the wireless device to select at least one beam by being configured to cause the wireless device to select at least one beam from multiple beams in the cell based on a reference signal received power RSRP threshold. In some embodiments in this regard, at least one of the selected beams includes at least one of the following: an SSB beam selected from multiple synchronization signal block SSB beams in the cell; and a CSI-RS beam selected from multiple channel state information reference signal CSI-RS beams in the cell.

[0081] In some embodiments in this regard, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to the selected at least one beam, the PUSCH configuration indicating the first and second resource allocations for the PUSCH transmission for msgA; a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being mapped to the PRACH configuration associated with the selected at least one beam; and a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being based on the logical channel for which the two-step RA procedure is performed.

[0082] In some embodiments in this regard, at least one selected beam is mapped to multiple frequency - multiplexed random access channel (RACH) opportunities in a time resource. In some embodiments in this regard, the size of a first resource allocation for PUSCH transmission of msgA is different from the size of a second resource allocation for PUSCH transmission of msgA. In some embodiments in this regard, a two - step RA configuration is received in system information. In some embodiments in this regard, the processing circuitry is further configured to cause a wireless device to: determine a set of information bits for PUSCH transmission of msgA, the set of information bits corresponding to a payload; determine a transport block size based on at least one of a modulation and coding scheme, a number of orthogonal frequency - division multiplexing (OFDM) symbols, and a number of physical resource blocks indicated in a first and a second resource allocation in the two - step RA configuration; when the set of information bits is less than or equal to the transport block size, transmit a PUSCH transmission of msgA including the information bits; and when the set of information bits is greater than the transport block size, remove at least one bit from the set of information bits based on the priority of the logical channel for which the two - step RA process is performed.

[0083] According to another aspect of the present disclosure, there is provided a network node configured to communicate with a wireless device. The network node includes processing circuitry. The processing circuitry is configured to cause the network node to send to the wireless device a two - step random access (RA) configuration for a cell, the two - step RA configuration including: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two - step RA process, the first resource allocation for PUSCH transmission of msgA being associated with a first set of preambles; and a second resource allocation for PUSCH transmission of msgA associated with a second set of preambles. The processing circuitry is configured to cause the network node to receive a PUSCH transmission of msgA according to one of the first and second resource allocations, the one of the first and second resource allocations and the associated one of the first and second sets of preambles being based on the two - step RA configuration and the payload size of the PUSCH transmission of msgA.

[0084] In some embodiments in this regard, the processing circuitry is configured to cause the network node to receive a preamble of a msgA transmission of a two-step RA procedure, the preamble being from one of a first preamble set and a second preamble set based on a two-step RA configuration and a payload size of a PUSCH transmission of msgA. In some embodiments in this regard, the two-step RA configuration further includes a size threshold associated with first and second resource allocations of the two-step RA configuration; and the processing circuitry is configured to cause the network node to receive a PUSCH transmission of msgA by being configured to cause the network node to perform the following: when the payload size is greater than the size threshold, receive the PUSCH transmission of msgA according to the second resource allocation and the associated second preamble set; otherwise, receive the PUSCH transmission of msgA according to the first resource allocation and the associated first preamble set.

[0085] In some embodiments in this regard, the two-step RA configuration further includes a path loss threshold associated with the second preamble set; and the processing circuitry is configured to cause the network node to receive a PUSCH transmission of msgA by being configured to cause the network node to perform the following: receive the PUSCH transmission of msgA according to the second resource allocation and the associated second preamble set only when the estimated downlink path loss is less than the path loss threshold. In some embodiments in this regard, each of the first and second resource allocations includes at least one of the following: time resources; frequency resources; modulation and coding schemes; transmit power instructions; and redundancy versions. In some embodiments in this regard, one of the first and second resource allocations for receiving a PUSCH transmission of msgA is further based on the respective modulation and coding schemes of the first and second resource allocations.

[0086] In some embodiments in this regard, one of the first and second resource allocations for receiving a PUSCH transmission of msgA is further based on the respective transmit power instructions of the first and second resource allocations. In some embodiments in this regard, the two-step RA configuration further includes a transmit power threshold associated with the first and second preamble sets; and one of the first and second resource allocations for receiving a PUSCH transmission of msgA and the associated one of the first and second preamble sets are based on whether the estimated transmit power meets the transmit power threshold.

[0087] In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the logical channel for which the two-step RA procedure is performed. In some embodiments in this regard, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on whether the wireless device is an ultra-reliable low-latency communication (URLLC) device. In some embodiments in this regard, the PUSCH transmission of msgA is received according to a two-step RA configuration associated with at least one beam in the cell selected by the wireless device.

[0088] In some embodiments in this regard, the two-step RA configuration includes a reference signal received power (RSRP) threshold, and at least one beam in the cell is selected by the wireless device based on the RSRP threshold. In some embodiments in this regard, at least one of the selected beams includes at least one of the following: an SSB beam selected from a plurality of synchronization signal block (SSB) beams in the cell; and a channel state information reference signal (CSI-RS) beam selected from a plurality of CSI-RS beams in the cell.

[0089] In some embodiments in this regard, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to at least one of the selected beams, the PUSCH configuration indicating the first and second resource allocations for the PUSCH transmission of msgA; a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one of the selected beams, and the PUSCH configuration being mapped to the PRACH configuration associated with at least one of the selected beams; and a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one of the selected beams, and the PUSCH configuration being based on the logical channel for which the two-step RA procedure is performed.

[0090] In some embodiments in this regard, at least one of the selected beams is mapped to a plurality of frequency-multiplexed random access channel (RACH) opportunities in a time resource. In some embodiments in this regard, the size of the first resource allocation for the PUSCH transmission of msgA is different from the size of the second resource allocation for the PUSCH transmission of msgA. In some embodiments in this regard, the two-step RA configuration is sent in the system information. In some embodiments in this regard, for each of the first and second resource allocations for the PUSCH transmission of msgA, the two-step RA configuration indicates at least one of a modulation and coding scheme, the number of orthogonal frequency-division multiplexing (OFDM) symbols, and the number of physical resource blocks. Description of the Drawings

[0091] A more complete understanding of the present embodiment and its attendant advantages and features will be more readily appreciated by reference to the following detailed description considered in conjunction with the accompanying drawings, in which:

[0092] Figure 1 Illustrates an example of a 4-step random access procedure;

[0093] Figure 2 Illustrates an example of a PRACH configuration in NR;

[0094] Figure 3 Illustrates an example of one SSB per PRACH occasion;

[0095] Figure 4 Illustrates an example of two SSBs per PRACH occasion;

[0096] Figure 5 Illustrates an example of the mapping between SSB and random access preamble;

[0097] Figure 6 Illustrates an example of the associated preamble for CBRA and CFRA for each SSB per PRACH occasion;

[0098] Figure 7 Illustrates an example of a two-step initial access procedure;

[0099] Figure 8 Illustrates examples of 4-step RA procedure and 2-step RA procedure;

[0100] Figure 9 Is a schematic diagram showing an exemplary network architecture of a communication system connected to a host computer via an intermediate network according to the principles of the present disclosure;

[0101] Figure 10 Is a block diagram of a host computer communicating with a wireless device via a network node through at least a partial wireless connection according to some embodiments of the present disclosure;

[0102] Figure 11 Is a flowchart showing an exemplary method for executing a client application at a wireless device implemented in a communication system including a host computer, a network node, and a wireless device according to some embodiments of the present disclosure;

[0103] Figure 12 Is a flowchart showing an exemplary method for receiving user data at a wireless device implemented in a communication system including a host computer, a network node, and a wireless device according to some embodiments of the present disclosure;

[0104] Figure 13is a flowchart showing an exemplary method for receiving user data from a wireless device at a host computer implemented in a communication system including a host computer, a network node, and a wireless device according to some embodiments of the present disclosure;

[0105] Figure 14 is a flowchart showing an exemplary method for receiving user data at a host computer implemented in a communication system including a host computer, a network node, and a wireless device according to some embodiments of the present disclosure;

[0106] Figure 15 is a flowchart of an exemplary process for a configuration unit in a network node according to some embodiments of the present disclosure; and

[0107] Figure 16 is a flowchart of an exemplary process for an RA unit in a wireless device according to some embodiments of the present disclosure. Detailed Description

[0108] For two-step RA, there may be an association between a random access preamble and the PUSCH transmission resource to be used for MsgA PUSCH (i.e., the PUSCH resource unit within a PUSCH occasion (PO)). Such a preamble-PUSCH resource association can be many-to-one, one-to-one, or even one-to-many.

[0109] Situations where two-step RO and four-step RO are shared and situations where two-step RO and four-step RO are configured separately can be considered.

[0110] Considerations:

[0111] ● For the relationship of PRACH resources between two-step RACH and four-step RACH, the network can flexibly configure the following options:

[0112] ○ Option 1: Configure separate ROs for two-step RACH and four-step RACH.

[0113] ○ Option 2: Share the RO, but use separate preambles for two-step RACH and four-step RACH.

[0114] Therefore, when two-step RO and four-step RO are shared, there may be a set of preambles dedicated to two-step RA in the cell. Otherwise, separate PRACH resources (e.g., time / frequency resources) can be provided for two-step RA. In the latter case, there can be, for example, N frequency-reused PRACH resources (i.e., occurring simultaneously but on different frequencies, e.g., different subcarriers), where M (M ≤ N) of these PRACH resources are associated with conventional four-step RA, and the remaining N - M PRACH resources are associated with two-step RA.

[0115] In the two-step random access procedure, PUSCH resource selection based on (transmitted) threshold payload size has not been considered yet. However, the modulation and coding status / scheme (MCS) and / or transport block size (TBS) can be configured for the msgA PUSCH as follows:

[0116] Considerations:

[0117] ● The following parameters can be defined for each msgA PUSCH configuration:

[0118] ○ The common parameters for Option 1 (separate configuration) and Option 2 (relative position) can at least include:

[0119] ■ MCS and / or transport block size (TBS) (to be further determined);

[0120] ■ The number of POs for FDMed;

[0121] ● The POs (including guard bands or guard periods if any) under the same msgA PUSCH configuration are continuous in the frequency domain;

[0122] ■ The number of PRBs for each PO;

[0123] ■ The number of DMRS symbols / ports / sequences (if supported) for each PO;

[0124] ■ To be further studied (FFS) whether repetition for msgA PUSCH is supported;

[0125] ■ The bandwidth of the FFS PRB-level guard band or the duration of the guard time;

[0126] ■ The FFS PUSCH mapping type;

[0127] ○ The parameters specific to Option 1 (separate configuration) at least include:

[0128] ■ Periodicity (msgA PUSCH configuration period);

[0129] ● The FFS value range;

[0130] ■ One or more offsets (e.g., symbols, time slots, subframes, etc.);

[0131] ■ Time domain resource allocation, details FFS, e.g., in the time slot for msgA PUSCH: starting symbol, number of symbols for each PO, number of time domain POs, etc.;

[0132] ■ Frequency starting point;

[0133] ○ The parameters specific to Option 2 can at least include:

[0134] ■Single time offset relative to a reference point (combination of slot-level and symbol-level indication);

[0135] ●FFS, e.g., each PRACH slot (e.g., start or end of a PRACH slot), etc.;

[0136] ■Number of symbols per PO;

[0137] ●FFS explicit or implicit indication;

[0138] ■Single frequency offset relative to FFS (start of the first RO in frequency or end of the last RO in frequency);

[0139] ○FFS: Number of TDM'ed POs;

[0140] ●Support multiple msgA PUSCH configurations for WD;

[0141] ○FFS maximum number of configurations;

[0142] ○FFS which parameters (if any) are common for all configurations;

[0143] ○FFS indication of different msgA PUSCH configurations, e.g., via different ROs, different preamble groups, or uplink control information (UCI);

[0144] ○FFS whether resources for different msgA PUSCHs can overlap in time-frequency and if so, any specification impacts;

[0145] ●FFS whether the frequency resources of msgA PUSCH should be restricted within the bandwidth of PRACH;

[0146] ●FFS verification rules for msgA PUSCH;

[0147] The following are considerations for power control of msgA PUSCH:

[0148] Consideration: During MsgA PUSCH retransmission, the transmit (Tx) power of MsgA PUSCH in transmission instance i is P PUSCH (i), where,

[0149]

[0150] -Δ MsgA_PUSCHIt is the offset relative to the target preamble reception power that can be configured for 2-step RACH. If the offset parameter does not exist, the parameter delta_preamble_msg3 for 4-step RACH is used.

[0151] -[Working assumption] from transmission format Δ TF The power component of (i) is determined based on the same mechanism and the same parameter deltaMCS of Rel-15 Msg3 for the current transmission instance.

[0152] - The power component αPL(i) from path loss compensation is determined by the alpha parameter, which is WD-specific, configured for 2-step and separated from 4-step RACH. If the 2-step RACH alpha parameter does not exist, the parameter msg3-alpha for 4-step RACH is used.

[0153] ○ FFS: Cell-specific MsgA PUSCH alpha.

[0154] - For the downlink path loss estimation used for MsgA PUSCH power control, WD uses the same RS resource index as that used for the corresponding MsgA PRACH.

[0155] - The power camping component is given by;

[0156]

[0157] ○ where, Δ rampuprequested is the boost requested to the higher layer.

[0158] ○ Further study and select from the following alternatives:

[0159] ■ Alternative 1: The boost for MsgA PUSCH and MsgA PRACH is the same

[0160] Δ rampuprequested =(PREAMPLE_POWER_PAMPING_COUNTER - 1)×[MsgA]powerRampingStep;

[0161] ■ FFS: The power boost counters for 2-step RACH MsgA PRACH and 4-step RACH Msg1 are the same;

[0162] ■ Alternative 2: The boost for MsgA PUSCH and MsgA PRACH is separated, with different counters

[0163] Δ rampuprequested= (MSGAPUSCH_POWER_RAMPING_COUNTER - 1) × PUSCHpowerRampingStep; and

[0164] ■ Alternative 3: The boost for MsgA PUSCH and MsgA PRACH is separate, with the same counter;

[0165] Δ rampuprequested = (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PUSCHpowerRampingStep.

[0166] The 2-step RA process can have the following advantages: The process reduces access latency, and for NR-U (NR unlicensed), it can also reduce the number of times the channel has to be accessed through the "listen before talk" (LBT) process. However, there may be a cost in terms of transmission resources, because the PUSCH transmission resources used for the transmission of MsgA PUSCH (e.g., RRCSetupRequest message, RRCResumeRequest message, or handover completion class messages such as RRCReconfigurationComplete) must be reserved for each 2-step RA occasion, regardless of whether they are used. Additionally, the resource efficiency of the MsgA PUSCH transmissions themselves is not very high, because they are sent without dynamic link adaptation (e.g., because the preamble on the PRACH is not included, which is the first transmission to the network, and thus the default configuration is used). Therefore, the 2-step RA including the 2-step RA occasion (PRACH resources and PUSCH resources) should be used with caution, and it may be beneficial to provide a method for selectively applying the 2-step RA based on relevant criteria. Ideally, the PUSCH resource selection can attempt to match the corresponding MsgA PUSCH payload size such that all PUSCH transport block (TB) resources carry user data and do not include padding bits.

[0167] Some embodiments of the present disclosure propose an arrangement that utilizes the following observations: 1) The nature of 5G / NR not only allows WD-specific transmission customization but also allows differentiation in the handling of physical layer transmission resources; 2) The nature (e.g., average load) and requirements (e.g., capacity / throughput, reliability, etc.) can be different between different types of payloads that trigger requests for transmission resources.

[0168] Some embodiments of the present disclosure include aspects of network nodes and WD. First, the aspects of network nodes are elaborated in detail below.

[0169] Some aspects of the present disclosure related to network nodes include making use of the above observations. For example, the network can flexibly and selectively configure support for two-step RA associated with a gradual difference in the number and size of PRACH transmission resources and / or PUSCH allocations dedicated to two-step RA. For example, changing the relationship between the number of two-step preambles, the number and size of PUSCH allocations. For example, the relationship between the number of preambles mapped to a PUSCH allocation and a set of PUSCH resource sizes.

[0170] As for the WD aspect, some embodiments include a method for performing random access with PUSCH resource selection at a wireless device (also referred to as a user equipment UE), the method including one or more of the following:

[0171] - Obtaining, for example, the (one or more) random access configurations for a target cell, which includes a two-step random access (RA) configuration for all beams, for each beam, or for a beam group, and the two-step RA configuration may include one or more thresholds for PUSCH resource selection related to the selected RO.

[0172] ○ The configuration may be provided in a handover command (RRCReconfiguration with synchronous reconfiguration), a reconfiguration message (RRCReconfiguration), as part of a beam failure recovery (BFR) configuration, broadcast in system information, etc.

[0173] ○ The configuration may be mapped directly or indirectly per beam. For example, there may be a relationship between the selected beam and the PRACH configuration, and thus a relationship between the PRACH configuration and the two-step RA configuration.

[0174] ○ When applying a one-to-many mapping between the preamble and the PUSCH resource, "related to the selected RO" here may also be "related to both the selected RO and the selected preamble". "Related to the selected RO" here may also mean one or more ROs frequency division multiplexed with the selected RO (if any), because the same beam is assumed in these frequency division multiplexed POs.

[0175] - Triggering random access (e.g., upon a request from the upper layer).

[0176] - Performing beam selection.

[0177] ○ For example, this could be SSB selection based on radio conditions, for example, where the WD selects the SSB with the highest RSRP among the detected SSBs for the relevant cell. During the transition from the RRC_IDLE or RRC_INACTIVE state to the RRC_CONNECTED state or when the WD in the RRC_CONNECTED state re-acquires valid timing advance, the cell in which the WD performs SSB selection can be the serving cell, or this cell can be the target cell or potential target cell for handover in combination. During handover in combination, beam selection can include selecting a CSI-RS beam in the target cell.

[0178] ○ This can be considered at least similar to what is described in 3GPP NR MAC Technical Specification (TS) 38.321 (version 15.6.0) "Random Access Resource Selection", where the selected beam (e.g., the selected SSB) is mapped to the resource for transmitting the preamble (however, in the case of 2-step RA, the selected beam can also be mapped to the resource for transmitting MsgA PUSCH on the PUSCH).

[0179] - Determine whether the selected beam (e.g., the selected SSB) has an associated 2-step RACH configuration. Note that the 2-step RACH configuration can be associated with all beams (i.e., all SSBs or all CSI-RSs), a subset of beams (i.e., a subset of SSBs or CSI-RSs), or no beams (i.e., none of the SSBs or CSI-RSs).

[0180] ○ In this context, the 2-step RA (configuration) can be the PRACH configuration and the mapping between the PRACH configuration associated with the selected beam and the PUSCH configuration (i.e., the indication of the PUSCH transmission resource and its selection for the transmission of MsgA PUSCH ).

[0181] ○ If all beams (e.g., SSBs or CSI-RSs) have an associated 2-step RACH configuration, then when the system information (SIB1) containing the SSB / CSI-RS to PRACH (and PUSCH) configuration (or the handover command in the form of an RRCReconfiguration IE with synchronous reconfiguration) is obtained, this determination step can be thoroughly performed in advance. Note that the determination that can still be retained at each new beam (e.g., SSB or CSI-RS) selection is which 2-step RACH configuration the SSB is associated with.

[0182] - Determine whether the 2-step RA configuration has PUSCH resources of different sizes (which can support the transmission of TBs of different sizes)

[0183] ○ Determine appropriate random access resources (preambles and PUSCH resources) for providing robust transmission of msgA PUSCH based on the expected payload size (e.g., TBS) of msgA PUSCH and possible radio conditions.

[0184] - Select preambles and msgA PUSCH resources based on selection criteria (e.g., thresholds) configured for msgA PUSCH size, radio conditions (e.g., path loss), and logical channels (e.g., common control channel or CCCH).

[0185] Advantageously, some embodiments allow the network / network node (e.g., gNB) to be able to configure the two-step random access procedure to allow the WD to select appropriate random access resources that best meet the appropriate size for msgA PUSCH transmission.

[0186] Before describing the exemplary embodiments in detail, note that the embodiments mainly lie in the combination of apparatus components and processing steps related to PUSCH resource selection in two-step random access (RA). Therefore, the components are represented by conventional symbols in the drawings, and the drawings only show those specific details relevant to understanding the embodiments, so as not to obscure the disclosure with details that are obvious to those skilled in the art who benefit from the description herein. The same numerals refer to the same elements throughout the description.

[0187] As used herein, relational terms such as “first” and “second”, “top” and “bottom” may be used only to distinguish one entity or element from another entity or element, and do not necessarily require or imply any physical or logical relationship or order between such entities or elements. The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are also intended to include the plural forms unless the context clearly dictates otherwise. It will be further understood that when the terms “comprises”, “comprising”, “includes” and / or “including” are used herein, they specify the presence of the 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.

[0188] In the embodiments described herein, the coupling term “communicating with” etc. may be used to indicate electrical or data communication that can be achieved, for example, by physical contact, induction, electromagnetic radiation, radio signals, infrared signals or optical signals. Those of ordinary skill in the art will understand that multiple components can interoperate and modifications and variations to achieve electrical and data communication are possible.

[0189] In some embodiments described herein, terms such as "coupled", "connected", etc. may be used herein to indicate a connection, although not necessarily a direct connection, and may include wired and / or wireless connections.

[0190] The term "network node" as used herein may be any type of network node included in a radio network, which may further include a 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 e-node B), node B, multi-standard radio (MSR) radio nodes such as MSR BS, multi-cell / multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling the relay, radio access point (AP), transmission point, transmission node, remote radio unit (RRU), remote radio head (RRH), core network node (e.g., mobility management entity (MME), self-organizing network (SON) node, coordination node, positioning node, MDT node, etc.), external node (e.g., third-party node, node external to the current network), node in a distributed antenna system (DAS), spectrum access system (SAS) node, network element management system (EMS), etc. The network node may also include test equipment. The term "radio node" as used herein may also be used to denote a wireless device (WD), such as a wireless device (WD) or a radio network node.

[0191] In some embodiments, the non-limiting terms "wireless device (WD)" or "user equipment (UE)" may be used interchangeably. A WD herein may be any type of wireless device capable of communicating with a network node or another WD via radio signals, such as a wireless device (WD). A WD may also be a radio communication device, a target device, a device-to-device (D2D) WD, a machine type WD or a WD capable of machine-to-machine communication (M2M), a low-cost and / or low-complexity WD, a WD equipped with sensors, a tablet, a mobile terminal, a smart phone, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a customer premise equipment (CPE), an Internet of Things (IoT) device or a narrowband Internet of Things (NB-IoT) device, etc.

[0192] Furthermore, in some embodiments, the general term "radio network node" is used. It can be any type of radio network node, which can include any one of a 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), IAB node, relay node, access point, radio access point, remote radio unit (RRU), remote radio head (RRH).

[0193] In some embodiments, the term "msgA" is used to indicate the PUSCH transmitted in the two-step RA procedure. However, it is expected that the term "msgA" may be changed in the future. Therefore, some embodiments of the present disclosure are not limited to this specific term that may change, but are limited to the basic principles, arrangements, and concepts disclosed herein.

[0194] The term "signaling" as used herein may include any of the following: high-layer signaling (e.g., via radio resource control (RRC), etc.), low-layer signaling (e.g., via physical control channels or broadcast channels), or a combination thereof. Signaling can be implicit or explicit. Signaling can also be unicast, multicast, or broadcast. Signaling can also be sent directly or via a third node to another node.

[0195] Generally, it can be considered that the network (e.g., the signaling radio node and / or the node arrangement (e.g., network node 16)) configures the WD 22, particularly with transmission resources. Resources can generally be configured with one or more messages. Different resources can be configured with different messages and / or with messages on different layers or layer combinations. The size of the resources can be expressed in symbols and / or subcarriers and / or resource elements and / or physical resource blocks (depending on the domain) and / or in terms of the number of bits it can carry (e.g., information or payload bits, or total bits). Resource sets and / or sets of resources can belong to the same carrier and / or bandwidth part, and / or can be located in the same time slot, or in adjacent time slots.

[0196] Receiving (or obtaining) information can include receiving one or more information messages (e.g., two-step RA configuration information). Receiving signaling can be considered to include, for example, demodulating and / or decoding and / or detecting one or more messages, particularly messages carried by the signaling, based on a set of assumed resources where the information can be searched for and / or listened to. It can be assumed that both parties to the communication know the configuration and can determine the set of resources, for example, based on a reference size.

[0197] Signaling can generally include one or more symbols and / or signals and / or messages. A signal can include or represent one or more bits. An indication can represent signaling and / or be implemented as a signal or signals. One or more signals can be included in a message and / or represented by a message. Signaling, particularly control signaling, can include multiple signals and / or messages, which can be sent on different carriers and / or associated with different signaling procedures, which for example represent one or more such procedures and / or corresponding information and / or are related thereto. An indication can include signaling and / or multiple signals and / or messages and / or can be included therein, which can be sent on different carriers and / or associated with different acknowledgment signaling procedures, which for example represent one or more such procedures and / or are related thereto. Signaling associated with a channel can be sent such that it represents signaling and / or information for that channel, and / or the signaling is interpreted by a transmitter and / or receiver as belonging to that channel. Such signaling can generally conform to the transmission parameters and / or format for the channel.

[0198] An indication can generally indicate explicitly and / or implicitly the information it represents and / or indicates. Implicit indication can be, for example, based on the location and / or resources used for transmission. Explicit indication can be, for example, based on parameterization with one or more parameters and / or one or more indices corresponding to a table and / or one or more bit patterns representing the information.

[0199] Transmission in the downlink can involve transmission from a network or network node to a terminal. The terminal can be considered a WD or UE. Transmission in the uplink can involve transmission from a terminal to a network or network node. Transmission in the sidelink can involve (direct) transmission from one terminal to another terminal. The uplink, downlink, and sidelink (e.g., sidelink transmission and reception) can be considered communication directions. In some variants, the uplink and downlink can also be used to describe wireless communication between network nodes, for example for wireless backhaul and / or relay communication, and / or (wireless) network communication between, for example, base stations or similar network nodes, particularly communication terminating at such network nodes. Backhaul and / or relay communication and / or network communication can be considered to be implemented as sidelink or uplink communication or a similar form.

[0200] Configure radio node

[0201] Configuring a radio node, particularly a terminal or user equipment or WD, can mean that the radio node is adapted or made or set and / or instructed to operate according to a configuration. The configuration can be carried out by another device, such as a network node (e.g., a radio node of a network, such as a base station or eNodeB), or a network. In this case, it can include sending configuration data to the radio node to be configured. Such configuration data can represent the configuration to be configured and / or include one or more instructions related to the configuration, such as a configuration for transmitting and / or receiving on the allocated resources (particularly frequency resources), or for example, a configuration for performing certain measurements on certain subframes or radio resources. The radio node can configure itself, for example, based on the configuration data received from the network or network node. The network node can use and / or be adapted to use one or more of its circuits to carry out the configuration. Allocation information can be considered a form of configuration data. The configuration data can include configuration information and / or one or more corresponding instructions and / or messages, and / or be represented thereby.

[0202] General configuration

[0203] Generally, configuring can include determining configuration data representing the configuration and providing (e.g., sending) it (in parallel and / or sequentially) to one or more other nodes, which one or more other nodes can further send it to the radio node (or another node, which can be repeated until it reaches the wireless device). Alternatively or additionally, configuring a radio node, for example, by a network node or other device can include: receiving configuration data and / or data related to the configuration data from another node (which can be a higher-level node of the network, such as a network node), and / or sending the received configuration data to the radio node. Thus, determining the configuration and sending the configuration data to the radio node can be performed by different network nodes or entities that are capable of communicating via a suitable interface (e.g., the X2 interface in the case of LTE or the corresponding interface for NR). Configuring a terminal (e.g., WD) can include: scheduling downlink and / or uplink transmissions for the terminal, such as downlink data and / or downlink control signaling and / or DCI and / or uplink control or data or communication signaling, particularly acknowledgment signaling, and / or configuring resources and / or resource pools therefor.

[0204] Any two or more embodiments described in this disclosure can be combined with each other in any way.

[0205] Note that although terms from a specific wireless system such as, for example, 3GPP LTE and / or New Radio (NR) may be used in this disclosure, this should not be construed as limiting the scope of the disclosure to the aforementioned systems. Other wireless systems, including but not limited to Wideband 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 the ideas covered in this disclosure.

[0206] Further note that functions described herein as being performed by a wireless device or a network node may be distributed across multiple wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network nodes and wireless devices described herein are not limited to being performed by a single physical device and, in fact, may be distributed among several physical devices.

[0207] Unless otherwise defined, all terms used herein (including technical and scientific terms) 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.

[0208] Some embodiments provide PUSCH resource selection in 2-step Random Access (RA). Referring again to the drawings, in which like elements are denoted by like reference numerals, in Figure 9FIG. 0 shows a schematic view of a communication system 10 according to an embodiment, such as a 3GPP-type cellular network that can support standards such as LTE and / or NR (5G). The communication system 10 includes an access network 12 (such as a radio access network) and a core network 14. The access network 12 includes a plurality of network nodes 16a, 16b, 16c (collectively referred to as network nodes 16), such as NB, eNB, gNB, or other types of wireless access points. Each network node defines a corresponding coverage area 18a, 18b, 18c (collectively referred to as coverage areas 18). Each network node 16a, 16b, 16c can be connected to the core network 14 via a wired or wireless connection 20. A first wireless device (WD) 22a located in the coverage area 18a is configured to be wirelessly connected to or paged by the corresponding network node 16a. A second WD 22b in the coverage area 18b can be wirelessly connected to the corresponding network node 16b. Although a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to the case where a single WD is in the coverage area or a single WD is connected to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include more WDs 22 and network nodes 16.

[0209] Furthermore, it is conceivable that the WD 22 can communicate with more than one network node 16 and more than one type of network node 16 simultaneously and / or be configured to communicate with them separately. For example, the WD 22 can have a dual connection with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, the WD 22 can communicate with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0210] The communication system 10 itself can be connected to a host computer 24, which can be embodied in the hardware and / or software of a stand-alone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm. The host computer 24 can be under the ownership or control of a service provider, or can be operated by or on behalf of a service provider. The connections 26, 28 between the communication system 10 and the host computer 24 can extend directly from the core network 14 to the host computer 24, or can extend via an optional intermediate network 30. The intermediate network 30 can be one of a public, private, or managed network or a combination of more than one of them. The intermediate network 30 (if any) can be a backbone network or the Internet. In some embodiments, the intermediate network 30 can include two or more sub-networks (not shown).

[0211] Figure 9The communication system as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. This connectivity can be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to convey data and / or signaling via the OTT connection using the access network 12, the core network 14, any intermediate network 30, and possibly another infrastructure (not shown) as intermediaries. The OTT connection can be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of the routing of the uplink and downlink communications. For example, the network node 16 may not or need not be informed about the past routing of the incoming downlink communication of data having a source from the host computer 24 that is to be forwarded (e.g., handed over) to the connected WD 22a. Similarly, the network node 16 need not know the future routing of the outgoing uplink communication from the WD 22a to the host computer 24.

[0212] The network node 16 is configured to include a configuration unit 32, and the configuration unit 32 is configured to configure the WD 22 for 2-step RA according to the principles in the present disclosure. The wireless device 22 is configured to include an RA unit 34, and the RA unit 34 is configured to perform 2-step RA according to the principles in the present disclosure.

[0213] Now, reference will be made to Figure 10 to describe an example implementation of the WD 22, the network node 16, and the host computer 24 discussed in the previous paragraphs according to an embodiment. In the communication system 10, the host computer 24 includes hardware (HW) 38, and the hardware (HW) 38 includes a communication interface 40 configured to establish and maintain a wired or wireless connection to the interfaces of different communication devices of the communication system 10. The host computer 24 further includes a processing circuit 42, and the processing circuit 42 may have storage and / or processing capabilities. The processing circuit 42 may include a processor 44 and a memory 46. In particular, in addition to or instead of a processor and a memory such as a central processing unit, the processing circuit 42 may include an integrated circuit for processing and / or control, e.g., one or more processors and / or processor cores and / or an FPGA (field programmable gate array) and / or an ASIC (application specific integrated circuit) suitable for executing instructions. The processor 44 may be configured to access (e.g., write to and / or read from) the memory 46, and the memory 46 may include any kind of volatile and / or non-volatile memory, e.g., a cache and / or a buffer memory and / or a RAM (random access memory) and / or a ROM (read only memory) and / or an optical memory and / or an EPROM (erasable programmable read only memory).

[0214] The processing circuitry 42 may be configured to control any of the methods and / or processes described herein, and / or cause such methods and / or processes to be performed, for example, by the host computer 24. The processor 44 corresponds to one or more processors 44 for performing the functions of the host computer 24 described herein. The host computer 24 includes a memory 46 configured to store data, programming software code, and / or other information described herein. In some embodiments, the software 48 and / or the host application 50 may include instructions that, when executed by the processor 44 and / or the processing circuitry 42, cause the processor 44 and / or the processing circuitry 42 to perform the processes described herein with respect to the host computer 24. The instructions may be software associated with the host computer 24.

[0215] The software 48 may be executed by the processing circuitry 42. The software 48 includes the host application 50. The host application 50 may be operable to provide services to a remote user (such as the WD 22 connected via the OTT connection 52 terminating at the WD 22 and the host computer 24). When providing services to the remote user, the host application 50 may provide user data transmitted using the OTT connection 52. "User data" may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured to provide control and functionality to a service provider and may be operated by or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, send to and / or receive from the network node 16 and / or the wireless device 22. The processing circuitry 42 of the host computer 24 may include a monitoring unit 54 configured to enable the service provider to observe, monitor, control, send to and / or receive from the network node 16 and / or the wireless device 22.

[0216] The communication system 10 further includes a network node 16 provided in the communication system 10 and including hardware 58 that enables the network node 16 to communicate with the host computer 24 and the WD 22. The hardware 58 may include: a communication interface 60 for establishing and maintaining a wired or wireless connection to interfaces of different communication devices of the communication system 10; and a radio interface 62 for at least establishing and maintaining a wireless connection 64 to the WD 22 located in the coverage area 18 served by the network node 16. The radio interface 62 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 communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct, or it may pass through the core network 14 of the communication system 10 and / or through one or more intermediate networks 30 outside the communication system 10.

[0217] In the illustrated embodiment, the hardware 58 of network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor such as a central processing unit and a memory, the processing circuitry 68 may include an integrated circuit for processing and / or control, for example, one or more processors and / or processor cores and / or an FPGA (field programmable gate array) and / or an ASIC (application specific integrated circuit) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and / or read from) the memory 72, which may include any kind of volatile and / or non-volatile memory, such as 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).

[0218] Accordingly, network node 16 also has software 74, which is stored internally, for example, in memory 72, or is stored in an external memory (e.g., a database, a storage array, a network storage device, etc.) accessible to network node 16 via an external connection. The software 74 may be executed by the processing circuitry 68. The processing circuitry 68 may be configured to control any method and / or process described herein, and / or cause such method and / or process to be executed, for example, by network node 16. The processor 70 corresponds to one or more processors 70 for performing the functions of network node 16 described herein. The memory 72 is configured to store data, program software code, and / or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and / or the processing circuitry 68, cause the processor 70 and / or the processing circuitry 68 to execute the processes described herein with respect to network node 16. For example, the processing circuitry 68 of network node 16 may include a configuration unit 32, which is configured to execute the network node methods discussed herein, such as the methods discussed with reference to Figure 15 and other figures.

[0219] The communication system 10 further includes the WD 22 already mentioned. The WD 22 may have hardware 80, which may include a radio interface 82 configured to establish and maintain a wireless connection 64 with network node 16 in the coverage area 18 where the serving WD 22 is currently located. The radio interface 82 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.

[0220] The hardware 80 of WD 22 further includes a processing circuit 84. The processing circuit 84 may include a processor 86 and a memory 88. In particular, in addition to or instead of a processor such as a central processing unit and a memory, the processing circuit 84 may include an integrated circuit for processing and / or control, for example, one or more processors and / or processor cores and / or an FPGA (Field Programmable Gate Array) and / or an ASIC (Application Specific Integrated Circuit) suitable for executing instructions. The processor 86 may be configured to access (e.g., write to and / or read from) the memory 88, and the memory 88 may include any kind of volatile and / or non-volatile memory, such as a cache and / or a buffer memory and / or a RAM (Random Access Memory) and / or a ROM (Read Only Memory) and / or an optical memory and / or an EPROM (Erasable Programmable Read Only Memory).

[0221] Thus, WD 22 may further include software 90, which is, for example, stored in the memory 88 at WD 22 or in an external memory accessible to WD (e.g., a database, a storage array, a network storage device, etc.). The software 90 may be executed by the processing circuit 84. The software 90 may include a client application 92. The client application 92 may be operable to provide services to a human or non-human user via WD 22 with the support of the host computer 24. In the host computer 24, the executed host application 50 may communicate with the executed client application 92 via the OTT connection 52 terminating at WD 22 and the host computer 24. When providing services to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transmit both the request data and the user data. The client application 92 may interact with the user to generate the user data it provides.

[0222] The processing circuit 84 may be configured to control any method and / or process described herein and / or cause such method and / or process to be executed by, for example, WD 22. The processor 86 corresponds to one or more processors 86 for executing the functions of WD 22 described herein. WD 22 includes a memory 88, which is configured to store data, programming software code, and / or other information described herein. In some embodiments, the software 90 and / or the client application 92 may include instructions that, when executed by the processor 86 and / or the processing circuit 84, cause the processor 86 and / or the processing circuit 84 to execute the processes described herein with respect to WD22. For example, the processing circuit 84 of the wireless device 22 may include a random access (RA) unit 34, and the random access (RA) unit 34 is configured to execute the WD methods discussed herein, such as the methods discussed with reference to Figure 16 and other figures.

[0223] In some embodiments, the internal workings of network node 16, WD 22, and host computer 24 can be as Figure 10 shown, and independently, the surrounding network topology can be Figure 9 the network topology of.

[0224] In Figure 10 , the OTT connection 52 has been abstractly depicted to illustrate the communication between host computer 24 and wireless device 22 via network node 16, without explicitly mentioning any intermediate devices and the exact routing of messages via these devices. The network infrastructure can determine the routing, which can be configured to hide the routing from WD 22 or from the service provider operating host computer 24 or from both. When the OTT connection 52 is active, the network infrastructure can further make a decision to dynamically change the routing (e.g., based on load balancing considerations or reconfiguration of the network).

[0225] The wireless connection 64 between WD 22 and network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of the OTT services provided to WD 22 using the OTT connection 52, in which the wireless connection 64 can form the last hop. More precisely, the teachings of some of these embodiments can improve data rate, latency, and / or power consumption, thereby providing benefits such as reduced user wait time, relaxed file size limitations, better responsiveness, extended battery life, etc.

[0226] In some embodiments, a measurement process may be provided for the purpose of monitoring data rate, latency, and other factors that one or more embodiments improve. There may also be optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and the WD 22 in response to changes in the measurement results. The measurement process and / or network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22 or in both. In an embodiment, sensors (not shown) may be deployed in or associated with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement process by providing values of the monitored quantities illustrated above, or by providing values of other physical quantities from which the monitored quantities can be calculated or estimated by the software 48, 90. Reconfiguring the OTT connection 52 may include message format, retransmission settings, preferred routing, etc.; the reconfiguration need not affect the network node 16, and the network node 16 may not know or be aware of it. Some such procedures and functionality may be known in the art and may be practiced. In certain embodiments, the measurement may involve proprietary WD signaling that facilitates measurement by the host computer 24 of throughput, propagation time, latency, etc. In some embodiments, the measurement may be implemented in that the software 48, 90 causes messages (especially empty messages or "dummy" messages) to be sent using the OTT connection 52 while it monitors propagation time, errors, etc.

[0227] Thus, in some embodiments, the host computer 24 includes a processing circuit 42 configured to provide user data and a communication interface 40 configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network further includes a network node 16 having a radio interface 62. In some embodiments, the network node 16 is configured to and / or the processing circuit 68 of the network node 16 is configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the WD 22 and / or preparing / terminating / maintaining / supporting / ending receiving a transmission from the WD 22.

[0228] In some embodiments, the host computer 24 includes a processing circuit 42 and a communication interface 40, the communication interface 40 being configured to receive user data sourced from a transmission from the WD 22 to the network node 16. In some embodiments, the WD 22 is configured to and / or includes a radio interface 82 and / or a processing circuit 84, the processing circuit 84 being configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the network node 16 and / or preparing / terminating / maintaining / supporting / ending receiving a transmission from the network node 16.

[0229] Although Figure 9 and 10Various "units", such as configuration unit 32 and RA unit 34, are shown within the corresponding processor, but 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, these units may be implemented in hardware or a combination of hardware and software within the processing circuitry.

[0230] Figure 11 is a flowchart of an exemplary method implemented in a communication system (such as, for example Figure 9 and Figure 10 the communication system). The communication system may include a host computer 24, a network node 16, and a WD 22, which may be those described with reference to Figure 10 In a first step of the method, the host computer 24 provides user data (block S100). In an optional sub-step of the first step, the host computer 24 provides user data by executing a host application (such as, for example, host application 50) (block S102). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (block S104). In an optional third step, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 sends the user data carried in the transmission initiated by the host computer 24 to the WD 22 (block S106). In an optional fourth step, the WD 22 executes a client application, such as, for example, client application 92 associated with the host application 50 executed by the host computer 24 (block S108).

[0231] Figure 12 is a flowchart of an exemplary method implemented in a communication system (such as, for example Figure 9 the communication system). The communication system may include a host computer 24, a network node 16, and a WD 22, which may be those described with reference to Figure 9 and Figure 10 In a first step of the method, the host computer 24 provides user data (block S110). In an optional sub-step (not shown), the host computer 24 provides user data by executing a host application (such as, for example, host application 50). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (block S112). In accordance with the teachings of the embodiments described throughout this disclosure, the transmission may pass through the network node 16. In an optional third step, the WD 22 receives the user data carried in the transmission (block S114).

[0232] Figure 13 is a flowchart of an exemplary method implemented in a communication system (e.g., Figure 9Flowchart of an exemplary method implemented in a communication system (such as, for example, the communication system). The communication system may include a host computer 24, a network node 16, and a WD 22, which may be those described with reference to Figure 9 and Figure 10 In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (block S116). In an optional sub-step of the first step, the WD 22 executes a client application 92, and the client application 92 provides user data in response to the received input data provided by the host computer 24 (block S118). Additionally or alternatively, in an optional second step, the WD 22 provides user data (block S120). In an optional sub-step of the second step, the WD provides user data by executing a client application (such as, for example, the client application 92) (block S122). When providing user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner of providing user data, in an optional third sub-step, the WD 22 may initiate the transmission of the user data to the host computer 24 (block S124). In a fourth step of the method, according to the teachings of the embodiments described throughout this disclosure, the host computer 24 receives the user data sent from the WD 22 (block S126).

[0233] Figure 14 is a flowchart of an exemplary method implemented in a communication system (such as, for example, Figure 9 the communication system). The communication system may include a host computer 24, a network node 16, and a WD 22, which may be those described with reference to Figure 9 and Figure 10 In an optional first step of the method, according to the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (block S128). In an optional second step, the network node 16 initiates the transmission of the received user data to the host computer 24 (block S130). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (block S132).

[0234] Figure 15FIG. 0 is a flowchart of an exemplary process for two-step RA configuration in network node 16 according to some embodiments of the present disclosure. One or more blocks and / or functions and / or methods performed by network node 16 may be performed by one or more elements of network node 16 according to an example method, such as by configuration unit 32, processor 70, radio interface 62, etc. in processing circuitry 68. The example method includes: sending (block S134), such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62, a two-step random access (RA) configuration for a cell to wireless device 22. The two-step RA configuration includes: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two-step RA process, the first resource allocation for PUSCH transmission of msgA being associated with a first preamble set; and a second resource allocation for PUSCH transmission of msgA associated with a second preamble set. The method includes: receiving (block S136), such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62, a PUSCH transmission of msgA according to one of the first and second resource allocations, the one of the first and second resource allocations and the associated one of the first and second preamble sets being based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA.

[0235] In some embodiments, the method includes: receiving, such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62, a preamble for a msgA transmission of the two-step RA process, the preamble being from one of a first and a second preamble set based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA. In some embodiments, the two-step RA configuration further includes a size threshold associated with the first and second resource allocations of the two-step RA configuration; and receiving the PUSCH transmission of msgA further includes: when the payload size is greater than the size threshold, receiving the PUSCH transmission of msgA according to the second resource allocation and the associated second preamble set; otherwise, receiving the PUSCH transmission of msgA according to the first resource allocation and the associated first preamble set, such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62.

[0236] In some embodiments, the two-step RA configuration further includes a path loss threshold associated with a second set of preambles; and receiving the PUSCH transmission of msgA further includes, such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62: receiving the PUSCH transmission of msgA according to a second resource allocation and an associated second set of preambles only if the estimated downlink path loss is less than the path loss threshold. In some embodiments, each of the first and second resource allocations includes at least one of the following: time resources; frequency resources; modulation and coding scheme; transmit power instruction; and redundancy version. In some embodiments, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the respective modulation and coding schemes of the first and second resource allocations.

[0237] In some embodiments, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the respective transmit power instructions of the first and second resource allocations. In some embodiments, the two-step RA configuration further includes a transmit power threshold associated with the first and second sets of preambles; and one of the first and second resource allocations for receiving the PUSCH transmission of msgA and an associated one of the first and second sets of preambles are based on whether the estimated transmit power meets the transmit power threshold. In some embodiments, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on the logical channel for which the two-step RA process is performed.

[0238] In some embodiments, one of the first and second resource allocations for receiving the PUSCH transmission of msgA is further based on whether the wireless device is an ultra-reliable low-latency communication (URLLC) device. In some embodiments, such as by configuration unit 32, processing circuitry 68, processor 70, and / or radio interface 62, receiving the PUSCH transmission of msgA according to a two-step RA configuration associated with at least one beam in a cell selected by the wireless device. In some embodiments, the two-step RA configuration includes a reference signal received power (RSRP) threshold, and the wireless device selects at least one beam in the cell based on the RSRP threshold. In some embodiments, the at least one selected beam includes at least one of the following: an SSB beam selected from a plurality of synchronization signal block (SSB) beams in the cell; and a channel state information reference signal (CSI-RS) beam selected from a plurality of CSI-RS beams in the cell.

[0239] In some embodiments, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to at least one selected beam, the PUSCH configuration indicating first and second resource allocations for PUSCH transmission of msgA; a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with at least one selected beam; and a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being based on the logical channel for which the two-step RA procedure is performed.

[0240] In some embodiments, at least one selected beam is mapped to a random access channel (RACH) opportunity with multiple frequency multiplexing in one time resource. In some embodiments, the size of the first resource allocation for PUSCH transmission of msgA is different from the size of the second resource allocation for PUSCH transmission of msgA. In some embodiments, the two-step RA configuration is sent in system information. In some embodiments, for each of the first and second resource allocations for PUSCH transmission of msgA, the two-step RA configuration indicates at least one of a modulation and coding scheme, the number of orthogonal frequency division multiplexing (OFDM) symbols, and the number of physical resource blocks.

[0241] In some embodiments, the method includes configuring at least one two-step random access (RA) configuration for the WD 22, such as via the configuration unit 32, the processing circuit 68, the processor 70, and / or the radio interface 62. The method includes receiving a preamble and / or a msgA PUSCH, such as via the configuration unit 32, the processing circuit 68, the processor 70, and / or the radio interface 62, the preamble and / or msgA PUSCH resources being at least partially based on at least one two-step RA configuration.

[0242] In some embodiments, the preamble and / or msgA PUSCH resources are further at least partially based on the two-step RA configuration associated with the beam selected by the WD. In some embodiments, the preamble and / or msgA PUSCH resources are further at least partially based on the payload size for the msgA PUSCH.

[0243] Figure 16FIG. 0 is a flowchart of an exemplary process for two-step RA in a wireless device 22 according to some embodiments of the present disclosure. One or more blocks and / or functions and / or methods performed by the WD 22 may be performed by one or more elements of the WD 22, such as by the RA unit 34, the processor 86, the radio interface 82, etc. in the processing circuitry 84. An example method for selecting resources for a two-step random access (RA) process implemented in a wireless device includes: receiving (block S138), such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, from a network node, a two-step RA configuration for a cell, the two-step RA configuration including: a first resource allocation for a physical uplink shared channel (PUSCH) transmission of a first message msgA for the two-step RA process, the first resource allocation for the PUSCH transmission of msgA being associated with a first preamble set; and a second resource allocation for the PUSCH transmission of msgA associated with a second preamble set. The method includes: selecting (block S140), such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, one of the first and second resource allocations and an associated one of the first and second preamble sets based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA. The method includes: transmitting (block S142) the PUSCH transmission of msgA using one of the first and second resource allocations selected.

[0244] In some embodiments, the method further includes: selecting, such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, a preamble for the msgA transmission for the two-step RA process from one of the first and second preamble sets selected; and transmitting, such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, the selected preamble of msgA. In some embodiments, selecting one of the first and second resource allocations and an associated one of the first and second preamble sets includes: comparing, such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, the payload size of the PUSCH transmission of msgA with a size threshold associated with the first and second resource allocations of the two-step RA configuration; when the payload size is greater than the size threshold, selecting, such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, the second resource allocation and the associated second preamble set; otherwise, selecting, such as by the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, the first resource allocation and the associated first preamble set.

[0245] In some embodiments, the two-step RA configuration further includes a path loss threshold associated with the second set of preambles, and selecting one of the first and second resource allocations and the associated one of the first and second sets of preambles further includes: comparing the estimated downlink path loss with the path loss threshold associated with the second set of preambles, such as by the RA unit 34, the processing circuit 84, the processor 86, and / or the radio interface 82; and selecting the second resource allocation and the associated second set of preambles, such as by the RA unit 34, the processing circuit 84, the processor 86, and / or the radio interface 82, only if the estimated downlink path loss is less than the path loss threshold. In some embodiments, each of the first and second resource allocations includes at least one of the following: time resources; frequency resources; modulation and coding schemes; transmit power instructions; and redundancy versions. In some embodiments, selecting one of the first and second resource allocations is further based on the respective modulation and coding schemes of the first and second resource allocations. In some embodiments, selecting one of the first and second resource allocations is further based on the respective transmit power instructions of the first and second resource allocations.

[0246] In some embodiments, the two-step RA configuration further includes a transmit power threshold associated with the first and second sets of preambles, and selecting one of the first and second resource allocations and the associated one of the first and second sets of preambles includes: estimating the transmit power of the PUSCH transmission for sending msgA on one of the first and second resource allocations, such as by the RA unit 34, the processing circuit 84, the processor 86, and / or the radio interface 82; and selecting one of the first and second resource allocations based on whether the estimated transmit power meets the transmit power threshold, such as by the RA unit 34, the processing circuit 84, the processor 86, and / or the radio interface 82. In some embodiments, selecting one of the first and second resource allocations and the associated one of the first and second sets of preambles is further based on the logical channel for which the two-step RA process is performed. In some embodiments, selecting one of the first and second resource allocations is further based on whether the wireless device is an ultra-reliable low-latency communication (URLLC) device.

[0247] In some embodiments, the method further includes: selecting, by, for example, the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, at least one beam among a plurality of beams in a cell; determining, by, for example, the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, that the selected beam is associated with a two-step RA configuration; and selecting, by, for example, the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, one of a first and a second resource allocation and an associated one of a first and a second preamble set using the two-step RA configuration associated with the selected beam. In some embodiments, selecting at least one beam further includes: selecting, by, for example, the RA unit 34, the processing circuitry 84, the processor 86, and / or the radio interface 82, at least one beam among a plurality of beams in a cell based on a reference signal received power (RSRP) threshold. In some embodiments, at least one of the selected beams includes at least one of the following: an SSB beam selected from among a plurality of synchronization signal block (SSB) beams in the cell; a CSI-RS beam selected from among a plurality of channel state information reference signal (CSI-RS) beams in the cell.

[0248] In some embodiments, the two-step RA configuration is included in one of the following: a PUSCH configuration mapped to the selected at least one beam, the PUSCH configuration indicating a first and a second resource allocation for PUSCH transmission of msgA; a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being mapped to the PRACH configuration associated with the selected at least one beam; and a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to the selected at least one beam, and the PUSCH configuration being based on a logical channel for which the two-step RA procedure is performed.

[0249] In some embodiments, at least one selected beam is mapped to a random access channel (RACH) occasion with multiple frequency multiplexing in a time resource. In some embodiments, the size of a first resource allocation for PUSCH transmission of msgA is different from the size of a second resource allocation for PUSCH transmission of msgA. In some embodiments, a two-step RA configuration is received in system information. In some embodiments, the method further comprises: determining, such as by RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, a set of information bits for PUSCH transmission of msgA, the set of information bits corresponding to a payload; determining, such as by RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, a transport block size based on at least one of a modulation and coding scheme, a number of orthogonal frequency division multiplexing (OFDM) symbols, and a number of physical resource blocks indicated in one of the first and second resource allocations in the two-step RA configuration; when the set of information bits is less than or equal to the transport block size, transmitting a PUSCH transmission of msgA including the information bits; and when the set of information bits is greater than the transport block size, removing at least one bit from the set of information bits, such as by RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, based on a priority of a logical channel for which a two-step RA procedure is performed.

[0250] In some embodiments, the method comprises: obtaining, such as by RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, at least one two-step random access (RA) configuration. The method comprises: selecting, such as by RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, a preamble and / or msgA PUSCH resource at least partially based on the at least one two-step RA configuration.

[0251] In some embodiments, the method further comprises: selecting, such as via RA unit 34, processing circuitry 84, processor 86, and / or radio interface 82, a beam, and the selection of the preamble and / or msgA PUSCH resource is at least partially based on the two-step RA configuration associated with the selected beam. In some embodiments, the selection of the preamble and / or msgA PUSCH resource is at least partially based on a payload size for msgA PUSCH.

[0252] The general processing flow of the arrangements of the present disclosure has been described, and examples of hardware and software arrangements for implementing the processes and functions of the present disclosure have been provided. The following sections provide details and examples of arrangements for PUSCH resource selection in two-step random access (RA), which can be implemented by network node 16, wireless device 22, and / or host computer 24.

[0253] Some embodiments will be discussed in more detail below.

[0254] Basic observations

[0255] Note that the two-step RA may involve UL PUSCH transmission (MsgA PUSCH), and due to the lack of customized link adaptation, this UL PUSCH transmission may have a higher failure risk than the average UL PUSCH transmission. By configuring an overly robust MCS (and possibly using an extremely high transmit power) for MsgA transmission (i.e., MsgA PUSCH) on the PUSCH compared to other solutions, this risk can be mitigated, but this may come at the cost of increased transmission resource usage and waste. Therefore, when the channel quality is relatively high, the two-step RA can be the most beneficial.

[0256] Some solution principles

[0257] To improve transmission resource usage in combination with the two-step RA configuration / process, a customized differentiation and selective use between possible (one or more) PUSCH resource allocations (e.g., of different sizes) are proposed, which improves the overall resource and process efficiency. As an example, a possible basis for partitioning and selectively using the differentiated two-step RA PUSCH resources is the handling of supporting and not supporting ultra-reliable low-latency communication (URLLC) WD 22 (i.e., WD 22 running URLLC applications and / or having UL RLLC class requirements). One scenario in the present disclosure is to have different resource allocations depending on the msgA PUSCH size (i.e., the payload size of the PUSCH transmission of msgA), also considering coverage and logical channels. As an example, a WD 22 in good coverage can successfully send a large MsgA PUSCH including RRC and user data, while a WD 22 in poor coverage can only send a small MsgA PUSCH on the same PUSCH resource size. When selecting the transmission resources for the transmission of MsgA PUSCH (from the allocated resources), the WD 22 can compare the (minimum) MsgA PUSCH size and the path loss with one or several thresholds associated with the PUSCH resource allocation to determine the appropriate preamble and PUSCH resources. This selection can also be conditioned on the logical channel for which the random access is performed. This selection can also consider other aspects, such as whether the random access is for a URLLC WD 22, in which case, PUSCH resources optimized for URLLC transmission are selected, for example, a larger allocation enables a more robust transmission.

[0258] WD details

[0259] Some embodiments of the present disclosure include methods for performing random access at a WD 22. In some embodiments, the method may include one or more of the following:

[0260] - Obtain the (one or more) random access configurations for a cell (e.g., provided by network node 16); for example, for the serving cell where WD 22 is camped (in RRC_IDLE or RRC_INACTIVE state) or for a target cell (in connection with handover), the (one or more) RA configurations include a two-step random access (RA) configuration for each beam or beam group in the cell (where a beam group constitutes a subset of the beams in the cell) or a two-step RA configuration applicable to all the (one or more) beams in the cell (where one or more beams can be used to transmit relevant reference signals) in the cell. When using a single SSB to cover the cell, it may be useful to associate the same two-step RA configuration with all the (one or more) beams in the cell. The reference signal being transmitted in the beam can be of the SSB or CSI-RS type;

[0261] ○ The above configurations can be provided during the configuration of handover, dual connectivity procedures (e.g., SCG addition, SCG change), carrier aggregation procedures (e.g., SCell establishment, SCell addition, SCell activation, etc.);

[0262] ○ The above configurations can be provided in the system information, where WD 22 obtains the configuration when camped on the cell and potentially accessing the cell.

[0263] ○ The configuration can be directly or indirectly mapped to the beam. For example, there can be a relationship between the selected beam and the PRACH configuration, and thus a relationship between the PRACH configuration and the two-step RA configuration.

[0264] ○ The configuration can be provided according to the reference signal (RS) type. For example, there can be a two-step RA configuration associated with each SSB (or each subset) in the SSB set and / or a two-step RA configuration associated with each CSI-RS (or each subset) in the CSI-RS set.

[0265] ○ The two-step RA configuration related to the beam can be encoded in RRC (ASN.1) and can be different, and depending on the solution, WD 22 obtains the two-step RA configuration in different IEs (e.g., mapped to PUSCH resources and their selection).

[0266] ■ In an alternative, WD 22 obtains the two-step RA configuration as part of the IE RACH-ConfigCommon.

[0267] ■ In an alternative, WD 22 obtains the two-step RA configuration as part of the IE RACH-ConfigDedicated.

[0268] ■ In an alternative, WD 22 obtains a two-step RA configuration as part of IE RACH-ConfigGeneric.

[0269] ■ In an alternative, WD 22 obtains a two-step RA configuration in multiple different IEs, where different parameters are provided in each IE, e.g., as part of IE RACH-ConfigGeneric and RACH-ConfigCommon, and may include a new IE to explicitly distinguish what the two-step RA configuration or four-step RA configuration is.

[0270] ■ In an alternative, different from the above cases, WD 22 obtains a two-step RA configuration in a new IE.

[0271] ○ When all SSBs are mapped to a set of RACH opportunities in one SSB-to-preamble association period, the beam group can be considered as the complete set of SSBs transmitted in the cell.

[0272] ○ Each beam can be referred to as a CSI-RS beam or an SSB beam. For example, when multiple frequency-multiplexed ROs in a time instance are mapped to an SSB beam, each SSB beam can be mapped to one or more RACH opportunities.

[0273] - Trigger random access (e.g., upon a request from the upper layer);

[0274] ○ For example, when RRC submits a message to the lower layer towards a target cell with which WD 22 is out of sync and reaches the MAC layer, such as when WD 22 receives a handover command (in the form of an RRCReconfiguration message with a synchronous reconfiguration IE) and should send a handover completion message (i.e., an RRCReconfigurationComplete message) in the target cell.

[0275] ○ RA can be triggered by any other procedure that depends on random access, e.g., detecting beam failure recovery, where WD 22 detects a beam failure and wants to select a beam from a list of candidate beams, and each candidate beam may have a two-step RA configuration.

[0276] ○Another situation that can trigger random access is when UL data appears in WD 22 (e.g., created by an application in WD 22). This will trigger random access if WD 22 is in the RRC_IDLE or RRC_INACTIVE state and needs to transition to the RRC_CONNECTED state before WD 22 can send the pending UL data. The pending UL data in WD 22 can also trigger random access if WD 22 in the RRC_CONNECTED state lacks a valid timing advance and needs to obtain a valid timing advance before WD 22 can send the pending UL data.

[0277] ○Another situation that can trigger random access is if WD 22 is paged and needs to transition to the RRC_CONNECTED state to respond to the paging.

[0278] ○Another situation that can trigger random access is if WD 22 receives a physical downlink control channel (PDCCH) command / instruction to perform random access to obtain a valid timing advance. This can occur if, for example, network node 16 receives DL data for WD 22 in the RRC_CONNECTED state that lacks a valid timing advance. Network node 16 will then command / instruct WD 22 to obtain a valid timing advance before the DL data is sent to WD 22 so that WD22 can send hybrid automatic repeat request (HARQ) feedback in the UL.

[0279] - Perform beam selection;

[0280] ○In one embodiment, performing beam selection can include, for example, performing SSB selection based on radio conditions, where WD 22 selects the SSB with the highest RSRP among the detected SSBs for the serving cell or the target cell. During the transition from the RRC_IDLE or RRC_INACTIVE state to the RRC_CONNECTED state or when WD 22 in the RRC_CONNECTED state re-obtains a valid timing advance, the cell in which WD 22 performs SSB selection, such as via processing circuit 84 for example, can be the serving cell, or the cell can be the target cell or a potential target cell in combination with a handover. In combination with a handover, beam selection can include selecting a CSI-RS beam in the target cell.

[0281] ○In some embodiments, this can be considered similar to what is referred to as "random access resource selection" in the MAC specification, where the selected beam (e.g., the selected SSB) is mapped to the resource for transmitting the preamble (however, in the case of 2-step RA, the selected beam can also be mapped to the resource for sending MsgA on the PUSCHPUSCH resources).

[0282] - Determine whether the selected beam (e.g., the selected SSB) has an associated two-step RACH configuration;

[0283] ○ In some embodiments, this step may be implemented by the WD 22, such as by checking via the processing circuit 84 for the presence of a random access configuration for the selected SSB or CSI-RS. That is, the presence of a two-step random access configuration indicates a mapping between the selected beam (e.g., SSB) and the two-step random access configuration.

[0284] ○ In some embodiments, the two-step RA configuration in this context may include a mapping between the selected beam and a PUSCH configuration (e.g., an indication of PUSCH transmission resources for MsgA PUSCH transmission).

[0285] ○ In some embodiments, the two-step RA configuration in this context may be a mapping between the PRACH configuration associated with the selected beam and the PUSCH configuration (for the transmission of MsgA PUSCH ). Compared with the above cases, this is an indirect mapping via the PRACH mapping.

[0286] ○ In some embodiments, the two-step RA configuration in this context may be a mapping between the PRACH configuration associated with the selected beam and the PUSCH configuration (for the transmission of MsgA PUSCH ), and this mapping includes a logical channel (LCH) mapping, where for URLLC data mapped to this LCH, the MsgA for this LCH mapping PUSCH reliability (e.g., in terms of MCS, PUSCH duration, etc.) is satisfied.

[0287] If a subset of the relevant RS beams (e.g., SSBs) has an associated two-step RA configuration, the WD 22 may determine whether a certain selected beam is one of the beams with an associated two-step RA configuration. Otherwise, if all or none of the relevant RS beams (e.g., SSBs) have an associated two-step RA configuration, the WD 22 determination may be made a priori, for example, only by obtaining the RA configuration in SIB1 in the system information. That is, in those cases, the WD22 may not have to determine whether a certain selected beam is one of the beams with an associated two-step RA configuration.

[0288] If the selected beam (e.g., the selected SSB) has an associated two-step RACH configuration, the WD 22 may be restricted from initiating a two-step RA procedure using the associated configuration to meet possible conditions (e.g., in terms of the estimated path loss). The configuration in this context may include a mapping between the selected beam and a PUSCH configuration (for the transmission of MsgA PUSCH).

[0289] In some embodiments, the association between the SSB and the msgA preamble, and between the SSB and the MsgA PUSCH configuration may depend on the beam relationship between the preamble transmission and the PUSCH transmission for one msgA.

[0290] In some embodiments, if the same beam corresponding to the SSB beam is required to be applied to the msgA preamble transmission and the MsgA PUSCH transmission, the selected SSB determines a pair of msgA preambles and msgA PUSCHs associated with the same beam corresponding to the SSB. In this case, the determined preamble indirectly determines the PUSCH resource via the mapping between the preamble and the PUSCH.

[0291] In some embodiments, if different beams corresponding to different SSBs are respectively applied to the msgA preamble transmission and the msgA PUSCH transmission, a set of SSBs that meet the link quality requirements can be used to determine the beam transmissions of the msgA preamble and the msgA PUSCH. The link quality requirements for the preamble and the PUSCH may also be different.

[0292] In some embodiments, one aspect of the two-step RA configuration of the present disclosure is how the selected beam (e.g., SSB-x or CSI-RS-x) is mapped to the PRACH resource and mapped to the PUSCH resource for the transmission of MsgA (i.e., PRACH preamble + MsgA PUSCH )). For transmitting MsgA PUSCHThe PUSCH resource selection can depend on the message size and / or the resulting transmission power associated with the selected preamble or on the estimated path loss. In some embodiments, for preamble transmission in a random access procedure, the transmission power or transmit power to be used is determined (e.g., by the WD 22, such as via the processing circuitry 84) using a formula that takes the estimated downlink path loss as input data. The WD 22 (such as via the processing circuitry 84) can estimate the downlink path loss by comparing the received signal power with the downlink transmit power indicated in the system information. The preamble transmit power is configured by the preambleReceivedTargetPower parameter in the RACH-ConfigGeneric IE.

[0293] In the 4-step RACH configuration in Rel-15 RRC TS 38.331 (version 15.6.0), the PRACH configuration index (prach-ConfigurationIndex) defines the time-domain and frequency-domain resources to be used for PRACH transmission, and a threshold message size (ra-Msg3SizeGroupA) is defined in RACH-ConfigCommon for preamble group resource selection (if such preamble group resource selection is included for the cell). In some embodiments herein, a similar threshold is defined for the 2-step RA procedure.

[0294] In some embodiments, a size threshold can be defined for the 2-step RA procedure. For example, the WD22 can select one of the first and second resource allocations and an associated one of the first and second preamble sets, e.g., by comparing the msgA PUSCH size (i.e., the payload size of the PUSCH transmission of msgA) with the size thresholds associated with the first and second resource allocations of the two-step RA configuration, and when the payload size is greater than the size threshold, select the second resource allocation and the associated second preamble set, otherwise, select the first resource allocation and the associated first preamble set.

[0295] To illustrate how the standard specification (specifically the RRC specification 3GPP TS 38.331, version 15.6.0) can be modified to support such selection and with respect to MsgA PUSCHSize-related preamble and PUSCH allocation selection. An example is disclosed herein where two preamble groups (e.g., MsgAGroupA and MsgAGroupB) are introduced for 2-step RA. Each preamble group can be associated with (or applicable to) a different msgA size (i.e., the payload size of the PUSCH transmission of msgA) (or size range), where the use of the preamble group is conditional on a msgA size threshold. For this example, the following can be specified as an example in the RRC specification 3GPP TS38.331 (version 15.6.0):

[0296] If MsgAGroupB is not configured, MsgAGroupA is always used.

[0297] If both MsgAGroupA and MsgAGroupB are configured, a threshold (e.g., ra-MsgASizeGroupA) can be defined to determine which group to use. If the msgA PUSCH size is less than the threshold, group A is used; otherwise, group B is used. "messageAPowerOffsetGroupB" can also be included as a threshold for preamble selection, and "numberOfRA-MsgAPreamblesGroupA" is included to determine the number of contention-based preambles in group A. Then, the remaining contention-based preambles are in group B.

[0298] The following can be included in the RACH-ConfigCommon IE:

[0299]

[0300] In some embodiments, the grouping of preambles can be related to the relationship between 2-step RO and 4-step RO, as described in more detail below.

[0301] When the 2-step RO and 4-step RO are configured separately, the preamble configuration and allocation for 2-step RA can be configured separately, and the preamble grouping for 2-step RA can be defined independently of the preamble grouping for 4-step RA.

[0302] When the 2-step RO and 4-step RO are shared, the 2-step RA preamble grouping can be mixed with the 4-step RO grouping to further split the preambles for 2-step RA from the preambles previously configured for 4-step RA. At least two examples are provided below for this case.

[0303] In one example, in addition to the existing groupBconfigured for the contention-based preamble group B configuration of msg1, group A configuration is also used. The numberOfRA-PreamblesGroupA_4step parameter is defined to determine the number of 4-step preambles in group A, and the remaining preambles in group A are used for 2-step RA. These remaining preambles can be further divided into two groups (MsgAGroupA and MsgAGroupB) based on MsgAgroupBconfigured (if configured).

[0304] The ASN.1 code example for this example is as follows.

[0305]

[0306]

[0307] Note: For consistency, for the parameters in the above ASN.1 code example, the following relationships are valid:

[0308] numberOfRA-PreamblesGroupA_4step < numberOfRA-PreamblesGroupA and numberOfRA-MsgAPreamblesGroupA < numberOfRA-PreamblesGroupA – numberOfRA-PreamblesGroupA_4step.

[0309] In another example, the total number of preambles for 2-step RA is defined by "numberOfRA-Preambles_2step", which includes the preambles for 2-step group A and 2-step group B (if configured). The 2-step group B preambles are derived from the total number of group B preambles for both 2-step RA and 4-step RA.

[0310]

[0311]

[0312] Note: For consistency, for the parameters in the above ASN.1 code example, the following relationship must be valid:

[0313] numberOfRA-MsgAPreamblesGroupA < numberOfRA-Preambles_2step, numberOfRA-MsgAPreamblesGroupA < numberOfRA-PreamblesGroupA and numberOfRA-Preambles_2step – numberOfRA-MsgAPreamblesGroupA < totalNumberOfRA-Preambles – numberOfRA-PreamblesGroupA.

[0314] In some embodiments, determining the set of preambles and PUSCH resources for MsgA (preamble + MsgA PUSCH ) transmission for the initiated RA procedure may be performed in one or more of the following ways:

[0315] As an embodiment, the preambles and PUSCH resources for transmitting MsgA PUSCH depend on the message size given by the two-step RA configuration, where one or several thresholds (msgA_size_1, msgA_size_2, …, msgA-size_n) are given. If the msgA size < msgA_size_1, preambles from preamble_group_0 are used, and if the msgA size >= msgA_size_k and < msgA_size_k+1 (i.e., msgA_size_k ≤ msgA size < msgA_size_k+1), then (e.g., by WD 22) preamble_group_k is used. Using this principle, in some embodiments, the number of thresholds is one less than the number of preamble groups, and one of the preamble groups is dedicated to the case where the highest threshold is exceeded. Note that a preamble group (and the corresponding PUSCH resource) may include only a single preamble (and PUSCH resource). These thresholds may be given in the two-step RACH configuration in the RRC specification (e.g., sent by network node 16). If only 2 groups are defined, as an option, the thresholds may reuse the thresholds configured for four-step RA, i.e., ra-Msg3SizeGroupA. In some embodiments, the number of groups may be configured by a higher layer (e.g., RRC), or the number of groups may be a fixed value. In some embodiments, the number of groups may be the same as the number of supported message sizes (e.g., the number of PUSCH resource allocation sizes). In some embodiments, the number of groups may be less than the number of supported message sizes, in which case each preamble group corresponds to one or more message sizes.

[0316] In some embodiments, a path loss threshold may be defined for 2-step RA. For example, a configuration (e.g., a 2-step RA configuration) may also include a path loss threshold associated with a set of preambles. The WD 22 may select a resource allocation and an associated set of preambles at least in part based on the path loss threshold. For example, a 2-step RA configuration may include a path loss threshold (per preamble group), and if the path loss (e.g., the estimated downlink path loss) is less than the path loss threshold for the preamble group, a particular preamble group (corresponding to the payload size of the PUSCH transmission of msgA, i.e., msgAsize) may be selected. That is, the selection of a particular preamble group may require the msgA size to meet the msgA size requirement and / or the path loss to meet the path loss requirement associated with the preamble group. For example, the WD 22 may compare the estimated downlink path loss with the path loss threshold associated with the set of preambles and select the resource allocation and the associated set of preambles only when the estimated downlink path loss is less than the path loss threshold.

[0317] Assume that the more stringent the path loss requirement (i.e., the smaller the path loss), the larger the message size. As a possible embodiment, if the msgA size matches preamble_group_k (e.g., msgA_size_k ≤ msgA size < msgA_size_k+1, or if msgA_size_k is the highest threshold, then msgA size ≤ msgA_size_k), but the path loss does not meet the corresponding path loss requirement for the preamble group (e.g., the path loss is too high), the WD 22, such as via the processing circuit 84, checks / determines whether the path loss is low enough for the preamble group associated with a msgA size one step smaller. If the check / determination is unsuccessful, the WD 22 tries the preamble group associated with a msgA size one step smaller, and so on. Preferably, in some embodiments, there is no path loss requirement associated with the preamble group associated with the smallest msgA size.

[0318] A possible alternative to the path loss requirement (e.g., the path loss must be below a threshold for the WD 22 to select a certain preamble group) may be to use other metrics related to signal strength or signal quality, such as reference signal received power (RSRP), reference signal received quality (RSRQ), reference signal strength indication (RSSI), signal-to-noise ratio (SNR), or signal-to-interference-plus-noise ratio (SINR). If an RSRP threshold is used, the requirement may be that the RSRP must exceed a certain threshold to allow the WD22 to select the corresponding preamble group.

[0319] In some embodiments, the threshold may be ignored in the case of performing random access for a specific logical channel (e.g., CCCH).

[0320] In some embodiments, the threshold may be specific to each beam (e.g., each associated SSB or each CSI-RS).

[0321] In some embodiments, the PRACH configuration index defines the time-frequency domain resources to be used for PRACH transmission, and where or in which relevant configuration elements the threshold message size and / or transmit power level are configured, such as one or more of the following:

[0322] ○ (e.g., by WD22 such as via processing circuitry 84 and / or radio interface 82) sending MsgA using a specific preamble and associated PUSCH resources determined by the message payload size (e.g., MAC service data unit (SDU) payload size)

[0323] ○ Alternatively or additionally, included in a 2-step RA configuration, the PUSCH resource selection is based on sending MsgA on the selected PUSCH time-frequency domain resources mapped to the selected preamble resource PUSCH The corresponding threshold estimates the transmit power.

[0324] As another example, if the preamble associated with the PUSCH resource selection does not depend on, for example, the message size given by a 2-step RA configuration (e.g., for MsgA PUSCH the process in the resource selection does not configure a threshold message size or transmit power), then WD 22 such as via processing circuitry 84 may possibly implement a specific estimate of WD 22 based on the suitability of the available PUSCH resource allocation relative to the size of the MsgA PUSCH message and / or the current radio channel conditions (e.g., in terms of path loss, RSRP, RSRQ, RSSI, SNR, or SINR), and select any preamble and PUSCH resources.

[0325] To further elaborate on possible embodiments of a method for selecting a preamble or preamble group having an associated PUSCH resource allocation among multiple preambles or preamble groups with associated PUSCH resource allocations of different sizes, the present disclosure provides as an example that two preamble groups may be configured for a 2-step RA, e.g., labeled as MsgAGroupA and MsgAGroupB, where each preamble group corresponds to a different PUSCH resource allocation size. For example, similar to 4-step RA, a size-related threshold may be associated with the preamble groups for 2-step RA to guide the selection of preamble groups by WD22.

[0326] However, in this context, the difference between 4-step RA and 2-step RA is that in 4-step RA, the UL grant for the transmission of Msg3 is given in Msg2 (RAR), and thus, the WD 22 does not know this UL grant when selecting the preamble group. Therefore, a Msg3 size threshold is needed to make the preamble group a rough indication of the size of Msg3, so that the network node 16 (e.g., gNB) can base the PUSCH resource allocation size on this information. Additionally, in 4-step RA, since the WD 22 does not know the MCS for Msg3 (and also does not know the number of PRBs to be allocated) when selecting the preamble group, the threshold for preamble group selection has to be expressed in terms of the Msg3 message size (i.e., in terms of information bits).

[0327] On the other hand, in 2-step RA, the WD 22 is typically provided with the PUSCH timing configuration via higher layer signaling (e.g., RRC) and thus knows the resource allocation for MsgA in terms of the number of physical resource blocks (PRBs) to be used, the number of orthogonal frequency division multiplexing (OFDM) symbols, and / or the MCS (unless the MCS can be dynamically selected by the WD 22). PUSCH Therefore, the WD 22 can calculate from the number of PRBs and / or OFDM symbols in the PUSCH timing configuration and the MCS to be applied, and thus derive the maximum message size (in terms of information bits) that can fit the PUSCH resource allocation associated with the corresponding preamble group. Therefore, in 2-step RA, a MsgA PUSCH size threshold does not need to be explicitly configured / signaled to the WD 22, because the WD 22 can determine, such as via the processing circuit 84 for example, which preamble group is suitable for a particular MsgA PUSCH message size. Therefore, the method for selecting the PUSCH resource allocation and the associated preamble or preamble group can be implemented in the WD 22 (e.g., using the principles described above), where the only information required from the network node 16 would be the 2-step RA configuration, which provides the PUSCH resource allocation (including time / frequency resources and possibly the demodulation reference signal (DMRS sequence) and / or DMRS port configuration as well as the MCS), the available preambles and their corresponding association with the PUSCH resource allocation. Note that optionally, the network node 16 can still configure the transmit power instruction associated with different PUSCH resource allocations (and thus associated with the (one or more) preambles or (one or more) preamble groups associated with the PUSCH resource allocation) (e.g., related to the estimated downlink path loss).

[0328] One way to determine the maximum message size that can be carried in a PUSCH occasion is to use the transport block size determination in, for example, section 6.4.1.2 of 3GPP TS 38.214 (version 15.6.0), which is calculated based on the modulation and coding status, number of OFDM symbols, and number of physical resource blocks to be used in the transmission in the PUSCH occasion. The transport block size N TBS is the number of higher layer bits that can be carried in a PUSCH occasion. This can be compared with the number of bits N info required to carry all the logical channels including the message, and if N info < N TBS , then the message will fit in the PUSCH occasion.

[0329] Thus, in embodiment “A”, the WD 22 (such as, for example, via the processing circuitry 84 and / or the radio interface 82) transmits a PUSCH during a random access procedure and indicates a configuration for the transmission of the PUSCH. The WD 22 (such as, for example, via the radio interface 82) receives higher layer Open Systems Interconnection (OSI) layer signaling that identifies a first and a second preamble set. The WD 22 further (such as, for example, via the radio interface 82) receives higher layer signaling that provides a first configuration for the PUSCH and identifies at least one of: the modulation and coding status, the number of OFDM symbols, and the number of physical resource blocks. The WD 22 (such as, for example, via the processing circuitry 84) may also determine a set of information bits to be transmitted, where the set includes N info information bits used by one or more logical channels. In some aspects, the WD 22 determines a first transport block size N TBS (1) based on at least one of the modulation and coding status, the number of OFDM symbols, and the number of physical resource blocks identified by the first configuration. If N info ≤ N TBS (1), then the WD 22 (such as, for example, via the radio interface 82 and / or the processing circuitry 84) may transmit a preamble identified by the first preamble set and may transmit a PUSCH carrying N info bits using the first configuration.

[0330] In some embodiments, if the network node 16 provides more than one configuration for the PUSCH occasion to the WD 22, the WD 22 may select the configuration that best matches the channel conditions, so as to send a larger msgA when the channel conditions are better and increase the throughput of msgA in the cell. In this case, the WD 22 may use, for example, the method described above to determine the transport block size that can be supported by each PUSCH occasion configuration that it can use for msgA transmission. Then, the WD 22 may select the configuration that can carry the bits available for transmission in msgA by selecting the configuration that supports the smallest transport block size that can still carry msgA.

[0331] The method described above may be implemented by a variant of the above-described embodiment "A", where the WD 22 further receives higher layer signaling that provides a second configuration for the PUSCH and identifies at least one of the modulation and coding state, the number of OFDM symbols, and the number of physical resource blocks. The WD22 may determine a second transport block size N TBS (2) according to at least one of the modulation and coding state, the number of OFDM symbols, and the number of physical resource blocks identified by the second configuration. In some embodiments, when N TBS (1)<N info ≤N TBS (2), the WD 22 transmits a preamble identified by the second preamble set and also uses the second configuration to transmit a PUSCH carrying the group of information bits.

[0332] Some of the proposed methods for the two-step RA procedure in the WD 22 may include one or more of the following steps:

[0333] 1. Receive a two-step RA configuration for the cell from the network node 16, such as receiving two-step RA configuration information from the network node 16, where the two-step RA configuration information includes one or more of the following:

[0334] ● PUSCH resource allocation, which includes one or more of the following:

[0335] i. Time / frequency resources.

[0336] ii. MCS.

[0337] iii. Transmit power instruction.

[0338] iv. Redundancy version (which may be fixed or hard-coded).

[0339] ● A preamble associated with PUSCH resource allocation. For example, the PUSCH resource allocation may include: a first resource allocation for the PUSCH of the first message msgA for the two-step RA process, and the first resource allocation for the PUSCH transmission of msgA may be associated with a first set of preambles; and a second resource allocation for the PUSCH transmission of msgA associated with a second set of preambles.

[0340] ● A transmit power command associated with the PUSCH resource allocation and / or the associated preamble.

[0341] i. For example, related to the downlink path loss.

[0342] 2. Obtain a trigger for initiating random access. This can be any of the events described above, such as:

[0343] ● UL data arrives at the UL buffer.

[0344] i. When the WD 22 is in the RRC_IDLE or RRC_INACTIVE state (including when the WD 22 is powered on or returns from a no-coverage period and needs to register in the network); or

[0345] ii. When the WD 22 is in the RRC_CONNECTED state and lacks a valid timing advance.

[0346] ● A paging message addressed to the WD 22 is received.

[0347] ● Perform a handover (i.e., triggered by a handover command received from the serving gNB / network node (i.e., an RRCReconfiguration message with a synchronization reconfiguration IE)) or an instruction to add an SCell).

[0348] ● A PDCCH command for initiating random access is received.

[0349] ● Determine that on-demand system information needs to be obtained (relevant if two-step RA end is specified for this random access scenario). This can be triggered by the following reasons:

[0350] i. Entering a new cell (the valid version of the relevant system information for this cell is not stored in the WD 22).

[0351] ii. Powering on the WD 22 (or returning after a lack of coverage period).

[0352] iii. The validity period of the relevant system information expires.

[0353] iv. Receiving a notification that the relevant system information has been updated.

[0354] ● Initiate an application or service or function in WD 22, which requires information from the SIB,

[0355] and the information has not been previously obtained and / or its valid version is not stored in WD 22. 3. If not already performed, select a beam (e.g., SSB or CSI-RS), and if not already completed, obtain the RA / RACH configuration associated with the selected beam.

[0356] 4. Determine that the two-step RA configuration and resources are available for the current beam (e.g., SSB or CSI-RS), and that two-step RA is suitable for triggering random access.

[0357] 5. Based on the two-step RA configuration, select the PRACH occasion to be used (in terms of time / frequency resources), e.g., the next one in time or one of the next few in case multiple PRACH occasions for two-step RA are frequency multiplexed.

[0358] 6. Determine the msgA size (i.e., the payload size of the PUSCH transmission of msgA) and compare it with the size of the available PUSCH resource allocation, possibly also considering other relevant aspects such as the current radio channel conditions (e.g., in terms of path loss, RSRP, RSRQ, RSSI, SNR or SINR), the (one or more) MCS associated with each available PUSCH resource allocation, and / or the possible transmit power commands (and their ultimate transmit power) associated with the available PUSCH resource allocations (e.g., the first and second PUSCH resource allocations).

[0359] 7. Based on the two-step RA configuration and the payload size of the PUSCH transmission of msgA, select one of the first and second PUSCH resource allocations and the associated one of the first and second preamble sets. For example, depending on the PUSCH resource allocation size (related to the msgA size, taking into account the effect of modulation and coding on the number of bits to be transmitted), other relevant aspects such as one or more of the following may also be considered to select the PUSCH resource allocation (or a set of PUSCH resource allocations of the same nature in terms of size and other possibly associated characteristics): the current radio channel conditions (e.g., in terms of path loss, RSRP, RSRQ, RSSI, SNR or SINR), the (one or more) MCS associated with each available PUSCH resource allocation, and / or the possible transmit power commands (and the ultimate transmit power) associated with the available PUSCH resource allocations (e.g., the first and second PUSCH resource allocations).

[0360] 8. Select a preamble for msgA transmission for the two-step RA process from one of the first and second preamble sets. For example, select a preamble associated with one of the selected PUSCH resource allocations or the selected multiple PUSCH resource allocations (if multiple PUSCH resource allocations have the same suitable / best characteristics).

[0361] ● There can be one preamble associated with each PUSCH resource allocation; or

[0362] ● A set of preambles is associated with each PUSCH resource allocation.

[0363] 9. Use one of the selected first and second PUSCH resource allocations to perform a PUSCH transmission of msgA. For example, transmit a MsgA that includes the selected preamble and MsgA PUSCH of MsgA.

[0364] ● The selected preamble is transmitted on the selected PRACH resource.

[0365] ● MsgA PUSCH is transmitted on the selected allocated PUSCH resource allocation (i.e., the PUSCH resource associated with the selected preamble).

[0366] 10. Receive MsgB from network node 16 and continue normal operations.

[0367] In some embodiments, the dynamic MCS selection described above is adopted, i.e., where a PUSCH resource allocation can be associated with multiple different MCSs, and WD 22 can, for example, select one MCS therefrom based on radio link quality (e.g., the estimated path loss, the measured RSRP, RSRQ, RSSI, SNR or SINR) and the MsgA PUSCH message size. The selection of the MCS and the PUSCH resource allocation size (and thus the preamble group) can be interleaved / executed jointly or sequentially. As an option, WD 22 can first determine the MCS based on radio link conditions (e.g., the estimated path loss) and the configured threshold (if any), and then, based on the required resource size resulting from applying the selected MCS on the MsgA PUSCH select the PUSCH resource allocation and the associated preamble group, for example, as described in Section 7.1.7 of 3GPP TS 38.213 (version 15.6.0) (the transport block size (TBS) would then be the MsgA PUSCHthe number of information bits therein and any additional padding bits used to fill the PUSCH resource allocation). As another option, WD 22 can first select the PUSCH resource allocation size (and thus select the associated preamble group), and then select an appropriate MCS to make MsgA PUSCH suitable for the selected allocated PUSCH resource (preferably, allowing MsgA PUSCH to be suitable for the most robust MCS of the selected allocated PUSCH resource). As yet another option, an iterative process can be applied to jointly select the MCS and the PUSCH resource allocation, or any other implementation of the selection process.

[0368] In some embodiments, if conditions related to the MsgA size are configured for using different PUSCH resource allocations (and thus for selecting the associated preamble or preamble group) for MsgA transmission, the following example changes marked in bold text can be applied to 3GPP NR specification TS 38.321 (version 15.6.0):

[0369] Random access resource selection

[0370] ****************************************************************

[0371] The MAC entity can:

[0372] 1> if the random access procedure is initiated for beam failure recovery (as specified in Subclause 5.17); and

[0373] 1> if the beamFailureRecoveryTimer (in Subclause 5.17) is running or not configured; and

[0374] 1> if the non-competitive random access resources for beam failure recovery requests associated with any one of the SSB and / or CSI-RS have been explicitly provided by the RRC; and

[0375] 1> if at least one of the SSBs in the candidateBeamRSList with SS-RSRP higher than rsrp-ThresholdSSB or the CSI-RSs in the candidateBeamRSList with CSI-RSRP higher than rsrp-ThresholdCSI-RS is available:

[0376] 2> Select an SSB in candidateBeamRSList with SS-RSRP higher than rsrp-ThresholdSSB among the SSBs or a CSI-RS in candidateBeamRSList with CSI-RSRP higher than rsrp-ThresholdCSI-RS;

[0377] 2> If a CSI-RS is selected and there is no ra-PreambleIndex associated with the selected CSI-RS:

[0378] 3> Set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the SSB quasi-co-located with the selected CSI-RS in candidateBeamRSList as specified in TS 38.214 (version 15.6.0), this SSB.

[0379] 2> Otherwise:

[0380] 3> Set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the SSB or CSI-RS selected from the set of random access preambles for beam failure recovery requests.

[0381] 1> Otherwise if ra-PreambleIndex has been explicitly provided by PDCCH; and

[0382] 1> If ra-PreambleIndex is not 0b000000:

[0383] 2> Set PREAMBLE_INDEX to the signaled ra-PreambleIndex;

[0384] 2> Select the SSB signaled by PDCCH.

[0385] 1> Otherwise if the non-competitive random access resources associated with the SSB have been explicitly provided in rach-ConfigDedicated and at least one SSB with SS-RSRP higher than rsrp-ThresholdSSB among the associated SSBs is available:

[0386] 2> Select an SSB with SS-RSRP higher than rsrp-ThresholdSSB among the associated SSBs;

[0387] 2> Set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the selected SSB.

[0388] 1> Otherwise, if non-competitive random access resources associated with CSI-RS have been explicitly provided in rach-ConfigDedicated, and at least one CSI-RS among the associated CSI-RS with CSI-RSRP higher than rsrp-ThresholdCSI-RS is available:

[0389] 2> Select a CSI-RS among the associated CSI-RS with CSI-RSRP higher than rsrp-ThresholdCSI-RS;

[0390] 2> Set PREAMBLE_INDEX to ra-PreambleIndex corresponding to the selected CSI-RS.

[0391] 1> Otherwise, if the random access procedure is initiated for an SI request (as specified in TS 38.331 (15.6.0)); and

[0392] 1> If random access resources for SI requests have been explicitly provided by RRC:

[0393] 2> If at least one SSB with SS-RSRP higher than rsrp-ThresholdSSB is available:

[0394] 3> Select an SSB with SS-RSRP higher than rsrp-ThresholdSSB.

[0395] 2> Otherwise:

[0396] 3> Select an SSB.

[0397] 2> Select a random access preamble corresponding to the selected SSB from the random access preambles determined according to ra-PreambleStartIndex specified in TS 38.331 (Release 15.6.0);

[0398] 2> Set PREAMBLE_INDEX to the selected random access preamble.

[0399] 1> Otherwise, if the random access procedure is a two-step RA procedure (i.e., for two-step contention-based random access preamble selection):

[0400] 2> If at least one SSB with SS-RSRP higher than rsrp-ThresholdSSB is available:

[0401] 3> Select an SSB with SS-RSRP higher than rsrp-ThresholdSSB.

[0402] 2> Otherwise:

[0403] 3> Select the SSB.

[0404] 2> If MsgA has not been sent yet:

[0405] 3> If a random access preamble group is configured:

[0406] 4> If the possible MsgA size (UL data available for transmission plus MAC header and MAC CE (if needed)) is less than ra-MsgASizeGroupk and greater than or equal to ra-MsgASizeGroupk-1 and the path loss is less than PCMAXgroupk-1 – preambleReceivedTargetPower – msg3-DeltaPreamble – messagePowerOffsetGroupk of the serving cell where the random access procedure is performed; or

[0407] 4> If the random access procedure is initiated for the CCCH logical channel and the CCCH SDU size plus the MAC sub-header is greater than ra-MsgASizeGroupk-1:

[0408] 5> Select random access preamble group k.

[0409] 4> Otherwise:

[0410] 5> Select random access preamble group k-1.

[0411] 3> Otherwise:

[0412] 4> Select random access preamble group A.

[0413] 2> Otherwise (i.e., MsgA is being retransmitted):

[0414] 3> Select the same random access preamble group as the random access preamble transmission attempt corresponding to the first transmission of MsgA.

[0415] 2> Randomly select a random access preamble with equal probability from the random access preambles associated with the selected SSB and the selected random access preamble group.

[0416] 2> Set PREAMBLE_INDEX to the selected random access preamble.

[0417] 1> Otherwise (i.e., for 4-step contention-based random access preamble selection):

[0418] 2> If at least one SSB with SS-RSRP higher than rsrp-ThresholdSSB is available:

[0419] 3>Select the SSB with SS-RSRP higher than rsrp-ThresholdSSB.

[0420] 2>Otherwise:

[0421] 3>Select the SSB.

[0422] 2>If Msg3 has not been sent yet:

[0423] 3>If random access preamble group B is configured:

[0424] 4>If the possible Msg3 size (UL data available for transmission plus MAC header and MAC CE (if needed)) is greater than ra-Msg3SizeGroupA and the path loss is less than PCMAX – preambleReceivedTargetPower – msg3-DeltaPreamble – messagePowerOffsetGroupB of the serving cell where the random access procedure is performed; or

[0425] 4>If the random access procedure is initiated for the CCCH logical channel and the CCCH SDU size plus the MAC sub-header is greater than ra-Msg3SizeGroupA:

[0426] 5>Select random access preamble group B.

[0427] 4>Otherwise:

[0428] 5>Random access preamble group A.

[0429] 3>Otherwise:

[0430] 4>Select random access preamble group A.

[0431] 2>Otherwise (i.e., Msg3 is being retransmitted):

[0432] 3>Select the same random access preamble group as the random access preamble transmission attempt corresponding to the first transmission of Msg3.

[0433] 2>Randomly select a random access preamble with equal probability from the random access preambles associated with the selected SSB and the selected random access preamble group.

[0434] 2>Set PREAMBLE_INDEX to the selected random access preamble.

[0435] 1>If the random access procedure is initiated by an SI request (as specified in TS 38.331 version 15.6.0); and

[0436] 1> If ra-AssociationPeriodIndex and si-RequestPeriod are configured:

[0437] 2> Determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB within the association period given by ra-AssociationPeriodIndex within si-RequestPeriod allowed by the restrictions given by ra-ssb-OccasionMaskIndex (if configured) (correspondingly, the MAC entity shall randomly select a PRACH occasion with equal probability among the consecutive PRACH occasions corresponding to the selected SSB according to Subclause 8.1 of TS 38.213 (version 15.6.0)).

[0438] 1> Otherwise if the SSB is selected as described above:

[0439] 2>, then determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB allowed by the restrictions given by ra-ssb-OccasionMaskIndex (if configured or indicated by PDCCH) (the MAC entity should randomly select a PRACH occasion with equal probability among the consecutive PRACH occasions corresponding to the selected SSB according to Subclause 8.1 of TS 38.213 (version 15.6.0); when determining the next available PRACH occasion corresponding to the selected SSB, the MAC entity may consider the possible occurrence of measurement gaps).

[0440] 1> Otherwise if CSI-RS is selected as described above:

[0441] 2> If there is no non-competitive random access resource associated with the selected CSI-RS:

[0442] 3> Determine the next available PRACH occasion from the PRACH occasions allowed by the restriction given by ra-ssb-OccasionMaskIndex (if configured) corresponding to the SSB that is quasi-co-located with the selected CSI-RS as specified in TS 38.214 (Release 15.6.0). (The MAC entity shall randomly select a PRACH occasion with equal probability among consecutive PRACH occasions corresponding to the SSB that is quasi-co-located with the selected CSI-RS in accordance with Subclause 8.1 of TS 38.213 (Release 15.6.0); when determining the next available PRACH occasion corresponding to the SSB that is quasi-co-located with the selected CSI-RS, the MAC entity may consider the possible occurrence of measurement gaps).

[0443] 2> Otherwise:

[0444] 3> Determine the next available PRACH occasion from the PRACH occasions corresponding to the selected CSI-RS in ra-OccasionList. (The MAC entity shall randomly select a PRACH occasion with equal probability among the PRACH occasions that occur simultaneously but on different subcarriers corresponding to the selected CSI-RS; when determining the next available PRACH occasion corresponding to the selected CSI-RS, the MAC entity may consider the possible occurrence of measurement gaps).

[0445] 1> Perform the random access preamble transmission procedure (see Subclause 5.1.3).

[0446] Note: When WD 22 determines whether there is an SSB with SS-RSRP higher than rsrp-ThresholdSSB or a CSI-RS with CSI-RSRP higher than rsrp-ThresholdCSI-RS, WD 22 uses the latest unfiltered layer 1 (L1)-RSRP measurement.

[0447] ************************************************************

[0448] Note 1: In the above example specification modification, for simplicity, it can be assumed that 2-step RA is not used for SI requests. However, if 2-step RA is to be applied to the Msg3-based SI request method (making Msg3 part of MsgA), the principles in this disclosure will also apply to this process.

[0449] Note 2: The above example specification modifications should be regarded exactly as examples. The example modifications do not cover all embodiments, and additionally, for a complete description of the solution of the present invention, additional specifications and specification sections will be affected.

[0450] Possible extensions and variations

[0451] Multiple MCSs per PUSCH resource allocation

[0452] In some embodiments, a possible extension or variation of the above solution is that in a two-step RA configuration, network node 16 associates a set of MCSs with each PUSCH resource allocation, and WD 22 can use one of the associated MCSs when transmitting MsgA PUSCH on the allocated PUSCH resource. As a possible configuration option, the lack of an explicit MCS configuration may mean that the set of MCSs includes all defined MCSs.

[0453] WD autonomously selects the MCS for MsgA PUSCH transmission

[0454] As an option, WD 22 autonomously selects the MCS (i.e., according to an implementation-related process), such as via processing circuitry 84. This autonomous selection can be based on radio channel conditions and / or the strength and / or quality of the received downlink transmission (e.g., the estimated path loss, the estimated BLER, the measured RSRP, RSRQ, RSSI, SNR, or SINR). The size of the MsgA PUSCH message (e.g., in information bits) related to the size of the associated PUSCH resource allocation (e.g., in PRBs) can also be input into the WD autonomous MCS selection algorithm. Other possible input data that can form part of the basis for the MCS selection can be the transmit power instruction (and its final transmit power) associated with the PUSCH resource allocation (if any) or the transmit power instruction (and its final transmit power) associated with a combination of the MCS and the PUSCH resource allocation, or the current power headroom of WD22 (e.g., related to the transmit power resulting from the transmit power instruction associated with the PUSCH resource allocation). Other inputs to the MCS selection algorithm of WD 22 can be the logical channel for MsgA PUSCH transmission, MsgA PUSCH whether it contains control signaling or user data or both, MsgA PUSCHis well-suited for segmentation, etc. As previously mentioned, the selection of the MCS can be integrated with the selection of the PUSCH resource allocation (and thus the associated preamble or preamble group), for example, intertwined in an iterative algorithm / process, or the selection of the PUSCH resource (and thus the associated preamble or preamble group) and the selection of the MCS can be performed sequentially, either first the MCS selection and then the PUSCH resource allocation (and thus the associated preamble or preamble group), or vice versa.

[0455] In some embodiments, when the WD 22 autonomously selects a combination of an appropriate size of the MCS and PUSCH resource allocation (given the MsgA PUSCH message size and MCS), the WD 22 can select different PUSCH resource allocation sizes that match the MsgA PUSCH message size by changing the selection of the MCS. This flexibility and freedom given to the WD 22 is accompanied by a risk that the WD 22 implementation tends to bias towards certain strategies, resulting in unforeseen and unwanted PUSCH resource allocation size selections (or an unwanted distribution of PUSCH resource allocation sizes across multiple WD 22s). To mitigate this risk, rules or conditions that prevent unwanted combination selections can be configured or specified. For example, there can be rules or conditions that prevent the WD 22 from selecting an overly large PUSCH resource allocation to avoid the WD 22 having a bias towards selecting large PUSCH resource allocations, which would increase the risk and frequency of preamble collisions. The largest PUSCH resource allocations should only be selected by the WD 22s that truly need them.

[0456] Network-guided selection of the MCS for MsgA PUSCH transmission

[0457] As another option, the network node 16 can guide or control the MCS selection of the WD 22, for example, through configured conditions (such as thresholds). Such thresholds can be related to any of the aspects mentioned above for the WD 22's autonomous MCS selection options, for example, radio channel conditions and / or the strength and / or quality of the received downlink transmission (e.g., the estimated path loss, the estimated BLER, the measured RSRP, RSRQ, RSSI, SNR, or SINR), the size of the MsgA PUSCH in terms of the size of the PUSCH resource allocation (e.g., in terms of the number of PRBs), the power headroom of the WD 22 (e.g., related to the transmit power generated from the transmit power command associated with the PUSCH resource allocation (if any), or related to the transmit power generated from the transmit power command associated with the MCS or the combination of the PUSCH resource allocation and the MCS), for MsgA PUSCHThe logical channel or MsgA for the transmission PUSCH Other aspects thereof (such as whether it contains control signaling or user data or both, how suitable it is for segmentation, etc.). Similarly, as described above, the selection of PUSCH resource allocation (and thus the associated preamble or preamble group) and MCS can be performed jointly, for example, as an iterative process or in sequence, either by first performing the MCS and then the selection of PUSCH resource allocation (and thus the associated preamble or preamble group), or vice versa. If the network node 16 guides the WD 22 to select the MCS and PUSCH resource allocation size and gives the WD 22 some degree of freedom, then rules or conditions to prevent unwanted selections (such as, as described above, a bias towards selecting an overly large PUSCH resource allocation) can also be useful in variants of this solution.

[0458] Combined MCS configuration and transmit power

[0459] In some embodiments, in a two-step RA configuration, different transmit power commands can be associated with each selectable MCS (e.g., each selectable MCS associated with the same PUSCH resource allocation). In this context, the transmit power command can include, for example, one or more parameters to be used in an algorithm for deriving the transmit power related to the estimated downlink path loss. Such parameters can, for example, affect how high the transmit power is set relative to the estimated path loss, and thus also affect the expected received power at the network node 16 (e.g., gNB).

[0460] In some embodiments, one principle for using different transmit power commands for different MCS configurations can be, for example, that the less robust the MCS, the higher the transmit power that can be generated from the associated command (in order to increase the received power at the network node 16 (e.g., gNB) to compensate for the less robust MCS). As mentioned above, the WD 22 can consider these configured transmit power commands when selecting the MCS (or when selecting a combination of PUSCH resource allocation and MCS (and transmit power)).

[0461] In some embodiments, a similar method can be based on power control for PUSCH occasions. As discussed in more detail above, in 3GPP RAN 1#97, the following power control formula for the MsgA PUSCH power P PUSCH (i) was agreed upon:

[0462]

[0463] First, it can be observed that the power control attempts to set the power to a nominal value represented by the following:

[0464]

[0465] However, if this term is greater than the maximum value P CMAX , then the formula limits the power to P CMAX . When the power is less than P CMAX , the power shall be within the range in which PUSCH shall operate with the desired reliability. When the power is greater than P CMAX , this may imply that there is not enough power available to transmit with the desired reliability.

[0466] Next, it can be observed that the power control varies with Δ TF (i), which will play the same role in the 2-step RACH as Δ TF,b,f,c (i) defined in Section 7.1.1 of 38.213 in 3GPP NR Rel-15:

[0467] For K s = 1.25

[0468] And Δ TF,b,f,c (i) = 0, for K s = 0

[0469] where K s is provided by deltaMCS for each UL BWP b of each carrier f and serving cell c. If the PUSCH transmission is over more than one layer [6, TS 38.214, version 15.6.0], then Δ TF,b,f,c (i) = 0. For each active UL BWP b of each carrier f and each serving cell c, BPRE and are calculated as follows.

[0470] This implies that Δ TF (i) will depend on the bits per resource element (BPRE) used in the msgA transmission and thus on the modulation and coding status (MCS) and the number of OFDM symbols used to transmit the PUSCH. It can be similarly observed that the power will depend on the number of resource blocks used and the power offset Δ MsgA_PUSCH . Therefore, when configuring any Δ TF (i), MCS, number of PRBs, and number of OFDM symbols to be used for a PUSCH occasion, they can affect whether WD22 has enough power to transmit the PUSCH using that configuration.

[0471] Thus, in an embodiment, the WD 22 (such as via processing circuitry 84 for example) selects a msgA PUSCH timing configuration based on whether there is sufficient power to transmit the configuration, and identifies it to the network node 16 by transmitting an associated preamble, and may optionally remove low-priority logical channels in order to achieve a msgA size that has sufficient power to transmit. The WD 22 may receive, from the network node 16 for example, higher layer signaling providing first and second configurations for the PUSCH, where each configuration identifies at least one of a modulation and coding state, a number of OFDM symbols, and a number of physical resource blocks. The WD 22 (such as via processing circuitry 84 for example) may also determine a set of information bits to be transmitted, the set including N info information bits used by one or more logical channels. The WD 22 may determine first and second transport block sizes N TBS (1) and N TBS (2) according to the respective at least one of the modulation and coding state, the number of OFDM symbols, and the number of physical resource blocks identified by each of the first and second configurations. In some embodiments, the WD 22 (such as via processing circuitry 84 for example) determines first and second powers for transmitting the PUSCH according to the first and second configurations. In some embodiments, if N TBS (1) < N info and the second power is greater than or equal to the maximum transmit power Pcmax, then the WD 22 (such as via processing circuitry 84 and / or radio interface 82) performs the step of removing the information bits used by the logical channel from the set of information bits according to the priority of one of the logical channels. Subsequently, if N TBS (1) < N info , then the WD 22 repeats the step of removing the information bits of the bits used by a different logical channel until N info ≤ N TBS (1). In some embodiments, next, the WD 22 transmits a preamble identified by a first set of preambles, and then transmits a PUSCH carrying the set of information bits using the first configuration. However, if N TBS (1) < N info ≤ N TBS (2) and the second power is less than Pcmax, then the WD 22 (such as via processing circuitry 84 and / or radio interface 82) may transmit a preamble identified by a second set of preamble powers, and then transmit a PUSCH carrying the set of information bits using the second configuration.

[0472] Receiving a MsgA PUSCH transmission with an unknown MCS

[0473] When network node 16 (e.g., gNB) receives MsgA with an unknown MCS (i.e., it is one of the optional MCSs associated with the PUSCH transmission resource) PUSCH during transmission, network node 16 (e.g., gNB) has to attempt blind decoding of MsgA PUSCH using each possible MCS until successful decoding or decoding fails for all possible MCSs.

[0474] Via the MCS indication of the associated preamble

[0475] As an option, each MCS associated with the PUSCH resource allocation for MsgA PUSCH transmission can have its own associated preamble (or set of preambles). For example, if two different MCSs are associated with the PUSCH resource allocation, two different preambles (or two disjoint sets of preambles) can be associated with the PUSCH resource allocation, one for each of the two MCSs. This solution can eliminate the need for network node 16 to perform blind decoding of MsgA PUSCH since network node 16 (e.g., gNB) can derive the MCS for MsgA PUSCH transmission from the received preamble.

[0476] Shrink msgA to fit the PUSCH timing

[0477] In some embodiments, WD 22 may have more data than can fit into the maximum PUSCH occasion that can be used by WD 22 for msgA. In such a case, rather than simply not sending msgA, a prioritization method may be used to discard lower-priority data from msgA. In Rel-15 NR, WD 22 may receive an uplink grant (such as, for example, via radio interface 82), from which WD 22 may determine the transport block size that can carry the higher layer data in the resources allocated by the grant in a PUSCH. When the grant is not sufficient to carry the message in Rel-15, WD 22 may discard lower-priority logical channels until the message size is small enough to fit within the grant. A grant is not typically provided to WD 22 in a 2-step RACH operation, and thus, WD 22 may determine the maximum message size for any logical channel priority, rather than being implicitly provided by the grant. Additionally, WD 22 may be configured with more than one PUSCH occasion configuration that it can use to carry msgA. In such a case, it may be desirable for WD 22 to send as much data as possible to increase the spectral efficiency of the network. The maximum amount of data to be sent may be determined, for example, by looking up the PUSCH occasion that supports the maximum transport block size among all the PUSCH occasion configurations provided to WD 22 by its configuration. Thus, when WD 22 has multiple PUSCH occasion configurations that it can use for msgA transmission, WD 22 may (such as, for example, via processing circuitry 84) determine the transport block size supported by each configuration and select the largest transport block size as the target size to be used for msgA in the logical channel prioritization process. In some embodiments, WD 22 removes one lower-priority logical channel at a time, starting with the lowest priority, removing all the bits carrying a given logical channel until the number of bits required for msgA is less than or equal to the transport block size. When the number of msgA bits is less than the transport block size, mechanisms such as padding or padding the buffer status report may optionally be used to increase the number of msgA bits to be closer to the transport block size.

[0478] One or more of the above methods may be implemented using an embodiment in which WD 22 receives (such as, for example, via processing circuitry 84 and / or radio interface 82) higher layer signaling (such as, for example, RRC) that identifies a first and a second set of preambles. WD 22 further receives (such as, for example, via processing circuitry 84 and / or radio interface 82) higher layer signaling that provides a PUSCH configuration and identifies at least one of a modulation and coding scheme, number of OFDM symbols, and number of physical resource blocks. WD 22 also determines (such as, for example, via processing circuitry 84) a set of information bits to be sent, where the set includes N used by one or more logical channels infoinformation bits. The WD 22 (such as, for example, via the processing circuitry 84) determines the transport block size N according to at least one of the modulation and coding status, the number of OFDM symbols, and the number of physical resource blocks identified by the PUSCH configuration TBS . When N info > N TBS , the WD 22 (such as, for example, via the processing circuitry 84) performs the step of removing the information bits used by one of the logical channels from the set of information bits according to the priority of the logical channel. Subsequently, when N info > N TBS , the WD 22 repeats the step of removing the information bits of the bits used by different logical channels until N info ≤N TBS . Then, the WD22 transmits a preamble identified by the first set of preambles and then transmits a PUSCH carrying the set of information bits using the configuration.

[0479] PUSCH resource allocation differentiated by MCS used conditional on channel quality

[0480] Another possible variant of the solution provided in the present disclosure is that different PUSCH resource allocations with corresponding associated preambles or groups of preambles are associated with different MCSs (although each PUSCH resource allocation has only one MCS). Then, if explicit conditions are configured for the selection of the preamble or group of preambles (based on their associated PUSCH resources and thus based on the associated MCS), these conditions can be expressed in terms of radio channel quality-related metrics such as the estimated path loss, the estimated BLER, RSRP, RSRQ, SNR or SINR. As a preferred example, the less robust the MCS, the better the signal / radio channel quality may be required (e.g., lower estimated path loss or BLER or higher RSRP, RSRQ, SNR or SINR). As an alternative to the explicitly configured signal / radio channel quality-related conditions, it can be left to WD 22 to autonomously determine whether a certain signal / radio channel quality is good enough to allow WD 22 to select a preamble or group of preambles associated with a certain MCS (where the association can be indirect via the PUSCH resource allocation). As yet another option, the conditions related to the signal / radio channel quality can be combined with the msgA size conditions, and different PUSCH resource allocations can have both different MCSs and different sizes. Note that for a given associated MCS, the PUSCH resource allocations can have different sizes in terms of the number of PRBs, but they can also differ in the number of information bits they can accommodate. For example, two different PUSCH resource allocations can have the same number of PRBs but different associated MCSs, and the PUSCH resource allocation with the less robust MCS will accommodate a larger number of information bits than the other PUSCH resource allocation.

[0481] Self-Organizing Network (SON) function learns the suitable PUSCH resource allocation size distribution

[0482] In some embodiments, the SON function can be used to learn which distribution of PUSCH resource allocation sizes (and associated conditions, if any) is suitable for the needs of WD 22 (where WD 22 in a particular network and / or area will have a distribution of different types of WD 22 or WD 22 with different user behaviors or WD 22 running different applications with different requirements and traffic patterns). The adaptation of such a suitable distribution of PUSCH resource allocation sizes should aim to achieve a reasonable uniform distribution of the allocated PUSCH transmission resources and thus the available preambles for WD22.

[0483] In some embodiments, the input data to the SON function can include statistical data on the behavior of WD 22s (possibly for each area) accessing the network, regarding the MsgA usedPUSCH Transmitted PUSCH resource allocation size, MsgA PUSCH Size of the message, and (if relevant) MCS aspects for MsgA PUSCH Transmission. Possibly, statistics related to the performed two-step random access procedure can also be part of the input data, e.g., statistics on preamble collisions, statistics on PUSCH resource allocation usage collisions, and / or success / failure statistics.

[0484] PUSCH resource configuration in the RRC release message

[0485] In this embodiment, when the connection is released to the idle or inactive mode (also referred to as the release message), the PUSCH resource configuration for the two-step RA can be provided by the network node 16 (e.g., gNB), such as via the processing circuitry 68 and / or the radio interface 62, for example. The resource configuration provided by the network node 16 (e.g., gNB) can be determined, for example, based on service requirements, traffic type (e.g., URLLC or machine type communication (MTC)), mobility of the WD 22, or type of the WD 22. This can allow certain high-priority WD 22s to be given resource configurations for larger and more robust allocations, and for low priority, to receive smaller and less frequent allocations. The resource configuration can also, for example, grant certain WD 22s access to more "high-quality" beams.

[0486] Some embodiments that can be implemented by the WD 22 and / or the network node 16 to configure two-step RA support can include one or more of the following:

[0487] 1. (The WD 22 (such as via the processing circuitry 84 and / or the radio interface 82) indicates whether msgA is suitable for RO to the network node 16 (e.g., gNB) by selecting and sending a preamble). A method of transmitting a PUSCH and indicating a configuration for the transmission of the PUSCH during a random access procedure (e.g., by the WD 22) includes one or more of the following:

[0488] a. The WD 22 receives (and the network node 16 sends) high-layer signaling identifying the first and second preamble sets;

[0489] b. The WD 22 receives (and the network node 16 sends) high-layer signaling providing a first configuration for the PUSCH and identifying at least one of the modulation and coding state, number of OFDM symbols, and number of physical resource blocks;

[0490] c. The WD 22 determines a set of information bits to be transmitted, where the set contains N info information bits used by one or more logical channels;

[0491] d. Based on at least one of the modulation and coding status, number of OFDM symbols, and number of physical resource blocks identified by the first configuration, WD 22 determines the first transport block size N TBS (1); and / or

[0492] e. If N info ≤N TBS (1), then

[0493] i. WD 22 transmits (and network node 16 receives) the preamble identified by the first preamble set, and

[0494] ii. Using the first configuration, WD 22 transmits (and network node 16 receives) the PUSCH carrying the set of information bits.

[0495] 2. (WD 22 discards low - priority logical channels so that msgA fits the PO) The method according to embodiment 1 further includes: When N info >N TBS (1),

[0496] a. WD 22 performs the step of removing the information bits used by one of the logical channels from the set of information bits according to the priority of the logical channel;

[0497] b. Subsequently, if N info >N TBS (1), then WD 22 repeats the step of removing the information bits of the bits used by different logical channels until N info ≤N TBS (1);

[0498] c. WD 22 transmits (and network node 16 receives) the preamble identified by the first preamble set; and

[0499] d. Using the first configuration, WD 22 transmits (and network node 16 receives) the PUSCH carrying the set of information bits.

[0500] 3. (WD 22 indicates which one of multiple configurations to use) The method according to any one of embodiments 1 and 2 further includes one or more of the following:

[0501] a. WD 22 receives (and network node 16 transmits) high - layer signaling that provides a second PUSCH configuration and identifies at least one of the modulation and coding status, number of OFDM symbols, and number of physical resource blocks; and

[0502] b. WD 22 determines the second transport block size N according to at least one of the modulation and coding status, number of OFDM symbols, and number of physical resource blocks identified by the second PUSCH configuration TBS (2); and / or

[0503] c. If N TBS (1) < N info ≤ N TBS (2), then

[0504] i. WD 22 transmits (and network node 16 receives) the preamble identified by the second preamble set, and

[0505] ii. Using the second configuration, WD 22 transmits (and network node 16 receives) the PUSCH carrying the set of information bits.

[0506] 4. (If the larger configuration requires too much power, discard the low-priority logical channels to fit the smaller configuration.) The method according to Embodiment 3 further includes one or more of the following:

[0507] a. WD 22 determines the first and second powers to be used for transmitting the PUSCH according to the first and second configurations;

[0508] b. If N TBS (1) < N info and the second power is greater than or equal to the maximum transmit power Pcmax, then

[0509] i. WD 22 performs the step of removing the information bits used by the logical channel from the set of information bits according to the priority of one of the logical channels;

[0510] ii. Subsequently, if N TBS (1) < N info , then WD 22 repeats the step of removing the information bits of the bits used by different logical channels until N info ≤ N TBS (1);

[0511] iii. WD 22 transmits (and network node 16 receives) the preamble identified by the first preamble set, and

[0512] iv. Using the first configuration, WD 22 transmits (and network node 16 receives) the PUSCH carrying the set of information bits.

[0513] c. If N TBS (1) < N info ≤ N TBS (2) and the second power is less than Pcmax, then:

[0514] i. The WD 22 transmits (and the network node 16 receives) a preamble identified by a second set of preambles, and

[0515] ii. Using the second configuration, the WD 22 transmits (and the network node 16 receives) a PUSCH carrying the set of information bits.

[0516] Some embodiments may include one or more of the following:

[0517] Embodiment A1. A network node configured to communicate with a wireless device (WD), the network node being configured to and / or including a radio interface and / or including a processing circuit, the processing circuit being configured to:

[0518] Configure at least one two-step random access (RA) configuration for the WD; and / or

[0519] Receive a preamble and / or a msgA PUSCH, the preamble and / or the msgA PUSCH resource being at least partially based on at least one two-step RA configuration.

[0520] Embodiment A2. The network node according to Embodiment A1, wherein:

[0521] The preamble and / or the msgA PUSCH resource is also at least partially based on a two-step RA configuration associated with the beam selected by the WD.

[0522] Embodiment A3. The network node according to Embodiment A1, wherein:

[0523] The preamble and / or the msgA PUSCH resource is also at least partially based on the payload size of the msgA PUSCH.

[0524] Embodiment B1. A method implemented in a network node, the method comprising:

[0525] Configure at least one two-step random access (RA) configuration for the WD; and / or

[0526] Receive a preamble and / or a msgA PUSCH, the preamble and / or the msgA PUSCH resource being at least partially based on at least one two-step RA configuration.

[0527] Embodiment B2. The method according to Embodiment B1, wherein:

[0528] The preamble and / or the msgA PUSCH resource is also at least partially based on a two-step RA configuration associated with the beam selected by the WD.

[0529] Embodiment B3. The method according to Embodiment B1, wherein:

[0530] The preamble and / or the msgA PUSCH resource is also at least partly based on the payload size of the msgA PUSCH.

[0531] Example C1. A wireless device (WD) configured to communicate with a network node, the WD being configured to and / or including a radio interface and / or a processing circuit, the processing circuit being configured to:

[0532] Obtain at least one two-step random access (RA) configuration; and / or

[0533] Select a preamble and / or a msgA PUSCH resource at least partly based on the at least one two-step RA configuration.

[0534] Example C2. The WD according to Example C1, wherein the WD is further configured to and / or the radio interface is further configured to and / or the processing circuit is further configured to:

[0535] Select a beam, and the selection of the preamble and / or the msgA PUSCH resource is at least partly based on the two-step RA configuration associated with the selected beam.

[0536] Example C3. The WD according to any one of Examples C1 and C2, wherein:

[0537] The selection of the preamble and / or the msgA PUSCH resource is at least partly based on the payload size of the msgA PUSCH.

[0538] Example D1. A method implemented in a wireless device (WD), the method comprising:

[0539] Obtain at least one two-step random access (RA) configuration; and / or

[0540] Select a preamble and / or a msgA PUSCH resource at least partly based on the at least one two-step RA configuration.

[0541] Example D2. The method according to Example D1, further comprising:

[0542] Select a beam, and the selection of the preamble and / or the msgA PUSCH resource is at least partly based on the two-step RA configuration associated with the selected beam.

[0543] Example D3. The method according to any one of Examples D1 and D2, wherein:

[0544] The selection of the preamble and / or the msgA PUSCH resource is at least partly based on the payload size of the msgA PUSCH.

[0545] As those skilled in the art will appreciate, the concepts described herein can be embodied as methods, data processing systems, computer program products, and / or computer storage media storing executable computer programs. Accordingly, the concepts described herein can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects, and all of these are collectively referred to herein as "circuits" or "modules" in this context. Any process, step, action, and / or functionality described herein can be performed by and / or associated with a corresponding module that can be implemented in software and / or firmware and / or hardware. Additionally, the present disclosure can 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 can be used, including a hard disk, CD-ROM, electronic storage device, optical storage device, or magnetic storage device.

[0546] Some embodiments are described herein with reference to flowcharts and / or block diagrams of methods, systems, and computer program products. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer (thereby creating a special purpose computer), a special purpose computer, or other programmable data processing apparatus to produce a machine such that the instructions executed via the processor of the computer or other programmable data processing apparatus create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0547] These computer program instructions can also be stored in a computer readable memory or storage medium, which 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 that implement the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0548] The computer program instructions can 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 executed on the computer or other programmable apparatus provide steps for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0549] It should be understood that the functions / actions marked in the boxes may not occur in the order marked in the operation instructions. For example, depending on the functionality / action involved, two consecutively shown boxes may actually be executed substantially simultaneously, or these boxes may sometimes be executed in the reverse order. Although some of the figures include arrows on the communication paths to indicate the main direction of communication, it should be understood that communication may occur in the direction opposite to the drawn arrows.

[0550] Computer program code for performing the operations of the concepts described herein may be written in an object-oriented programming language such as Java or C++. However, the computer program code for performing the operations of the present disclosure may also be written in a conventional programing language, such as the "C" programming language. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer. In the latter case, the remote computer may be connected to the user's computer via a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0551] In combination with the above description and the drawings, many different embodiments are disclosed herein. It should be understood that literally describing and illustrating every combination and sub-combination of these embodiments would be overly repetitive and confusing. Accordingly, all embodiments may be combined in any manner and / or combination, and this specification (including the drawings) should be construed as constituting a complete written description of all combinations and sub-combinations of the embodiments described herein, as well as the manner and process of making and using them, and should support claims to any such combination or sub-combination.

[0552] Those skilled in the art will understand that the embodiments described herein are not limited to what has been particularly shown and described above. Additionally, unless stated otherwise above, it should be noted that all of the drawings are not drawn to scale. Various modifications and variations can be made in accordance with the above teachings without departing from the scope of the appended claims.

Claims

1. A method for selecting resources for a two-step random access (RA) procedure implemented in a wireless device (22), the method comprising: Receiving (S138) from a network node (16) a two-step RA configuration for a cell, the two-step RA configuration including: a first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for the two-step RA procedure, the first resource allocation for the PUSCH transmission of the msgA being associated with a first preamble set; and a second resource allocation for the PUSCH transmission of the msgA associated with a second preamble set; Based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA, selecting (S140) one of the first resource allocation and the second resource allocation and an associated one of the first preamble set and the second preamble set; and Using the selected one of the first resource allocation and the second resource allocation to send (S142) the PUSCH transmission of the msgA; Wherein selecting one of the first resource allocation and the second resource allocation and an associated one of the first preamble set and the second preamble set includes: Comparing the payload size of the PUSCH transmission of the msgA with a size threshold associated with the first resource allocation and the second resource allocation of the two-step RA configuration; Comparing the estimated downlink path loss with a path loss threshold associated with the second preamble set; When the payload size is greater than the size threshold and the estimated downlink path loss is less than the path loss threshold, selecting the second resource allocation and the associated second preamble set; When the two-step RA procedure is initiated for a common control channel (CCCH) logical channel and the CCCH service data unit (SDU) size plus the media access control (MAC) sub-header is greater than the size threshold, selecting the second resource allocation and the associated second preamble set; and Otherwise, selecting the first resource allocation and the associated first preamble set.

2. The method according to claim 1, further comprising: Selecting a preamble for the msgA transmission of the two-step RA procedure from one of the first preamble set and the second preamble set; And Sending the selected preamble of the msgA.

3. The method according to claim 1, wherein, The two-step RA configuration further includes the size threshold.

4. The method according to claim 3, wherein, The two-step RA configuration further includes the path loss threshold.

5. The method according to any one of claims 1 to 4, wherein, Each of the first resource allocation and the second resource allocation includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version.

6. The method according to claim 5, wherein, Selecting one of the first resource allocation and the second resource allocation is further based on the respective modulation and coding schemes of the first resource allocation and the second resource allocation.

7. The method according to claim 5, wherein, Selecting one of the first resource allocation and the second resource allocation is further based on the respective transmit power commands of the first resource allocation and the second resource allocation.

8. The method according to claim 7, wherein The two-step RA configuration further includes transmit power thresholds associated with the first preamble set and the second preamble set, and selecting one of the first resource allocation and the second resource allocation and one of the associated first preamble set and the second preamble set includes: estimating the transmit power of the PUSCH transmission for transmitting the msgA on one of the first resource allocation and the second resource allocation; and selecting one of the first resource allocation and the second resource allocation based on whether the estimated transmit power meets the transmit power threshold.

9. The method according to any one of claims 1 to 4, wherein Selecting one of the first resource allocation and the second resource allocation is further based on whether the wireless device (22) is an ultra-reliable low-latency communication URLLC device.

10. The method according to any one of claims 1 to 4, further comprising: selecting at least one beam from among a plurality of beams in the cell; determining that the selected beam is associated with the two-step RA configuration; and and using the two-step RA configuration associated with the selected beam to select one of the first resource allocation and the second resource allocation and one of the associated first preamble set and the second preamble set.

11. The method according to claim 10, wherein selecting the at least one beam further comprises: selecting the at least one beam from among the plurality of beams in the cell based on a reference signal received power RSRP threshold; and the at least one selected beam includes at least one of the following: an SSB beam selected from among a plurality of synchronization signal block SSB beams in the cell; and a CSI-RS beam selected from among a plurality of channel state information reference signal CSI-RS beams in the cell.

12. The method according to claim 10, wherein, The two-step RA configuration is included in one of the following: a PUSCH configuration mapped to the at least one selected beam, the PUSCH configuration indicating the first resource allocation and the second resource allocation for the PUSCH transmission of the msgA; a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with the at least one selected beam; and a PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to the at least one selected beam, and the PUSCH configuration being based on the logical channel for which the two-step RA process is performed.

13. The method according to claim 10, wherein, The at least one selected beam is mapped to a plurality of frequency-multiplexed random access channel RACH opportunities in one time resource.

14. The method according to any one of claims 1 to 4, wherein The size of the first resource allocation for the PUSCH transmission of the msgA is different from the size of the second resource allocation for the PUSCH transmission of the msgA.

15. The method according to any one of claims 1 to 4, wherein, Receive the two-step RA configuration in system information.

16. The method according to any one of claims 1 to 4, further comprising: Determine a set of information bits for PUSCH transmission of the msgA, the set of information bits corresponding to the payload; Determine the transport block size according to at least one of the modulation and coding scheme, the number of orthogonal frequency division multiplexing (OFDM) symbols, and the number of physical resource blocks indicated in one of the first resource allocation and the second resource allocation in the two-step RA configuration; When the set of information bits is less than or equal to the transport block size, send a PUSCH transmission of the msgA including the information bits; And When the set of information bits is greater than the transport block size, remove at least one bit from the set of information bits based on the priority of the logical channel for which the two-step RA process is performed.

17. A method implemented in a network node (16), the network node being configured to communicate with a wireless device (22), the method comprising: Send (S134) a two-step random access (RA) configuration for a cell to the wireless device (22), the two-step RA configuration including: A first resource allocation for physical uplink shared channel (PUSCH) transmission of a first message msgA for a two-step RA process, the first resource allocation for the PUSCH transmission of the msgA being associated with a first set of preambles; and A second resource allocation for PUSCH transmission of the msgA associated with a second set of preambles; and Receive (S136) a PUSCH transmission of the msgA according to one of the first resource allocation and the second resource allocation, one of the first resource allocation and the second resource allocation and one of the first set of preambles and the second set of preambles associated therewith being based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA; Wherein receiving the PUSCH transmission of the msgA comprises: When the payload size is greater than a size threshold associated with the first resource allocation and the second resource allocation of the two-step RA configuration and the estimated downlink path loss is less than a path loss threshold associated with the second set of preambles, receive the PUSCH transmission of the msgA according to the second resource allocation; When the two-step RA process is initiated for a common control channel (CCCH) logical channel and the CCCH service data unit (SDU) size plus the media access control (MAC) sub-header is greater than the size threshold, receive the PUSCH transmission of the msgA according to the second resource allocation; and Otherwise, receive the PUSCH transmission of the msgA according to the first resource allocation.

18. The method according to claim 17, further comprising: Receive the preamble for the msgA transmission of the two-step RA process, the preamble being from one of the first preamble set and the second preamble set based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA.

19. The method according to claim 17, wherein The two-step RA configuration further includes the size threshold.

20. The method according to claim 19, wherein The two-step RA configuration further includes the path loss threshold.

21. The method according to any one of claims 17 to 20, wherein Each of the first resource allocation and the second resource allocation includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version.

22. The method according to claim 21, wherein One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on the corresponding modulation and coding scheme of the first resource allocation and the second resource allocation.

23. The method according to claim 21, wherein, One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on the corresponding transmit power instruction of the first resource allocation and the second resource allocation.

24. The method according to claim 23, wherein, The two-step RA configuration further includes a transmit power threshold associated with the first preamble set and the second preamble set; and One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA and one of the first preamble set and the second preamble set associated therewith are based on whether the estimated transmit power meets the transmit power threshold.

25. The method according to any one of claims 17 to 20, wherein One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on whether the wireless device (22) is an ultra-reliable low-latency communication URLLC device.

26. The method according to any one of claims 17 to 20, wherein Receive the PUSCH transmission of the msgA according to the two-step RA configuration associated with at least one beam in the cell selected by the wireless device (22).

27. The method according to claim 26, wherein, The two-step RA configuration includes a reference signal received power RSRP threshold, and the at least one beam in the cell is selected by the wireless device (22) based on the RSRP threshold; and The at least one selected beam includes at least one of the following: An SSB beam selected from a plurality of synchronization signal block SSB beams in the cell; And A CSI-RS beam selected from a plurality of channel state information reference signal CSI-RS beams in the cell.

28. The method according to claim 26, wherein, The two-step RA configuration is included in one of the following: A PUSCH configuration mapped to at least one selected beam, the PUSCH configuration indicating the first resource allocation and the second resource allocation for the PUSCH transmission of the msgA; A PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with at least one selected beam; And PUSCH configuration and Physical Random Access Channel (PRACH) configuration, where the PRACH configuration is mapped to at least one selected beam, and the PUSCH configuration is based on the logical channel for which the two-step RA procedure is performed.

29. The method according to claim 26, wherein The at least one selected beam is mapped to multiple frequency-multiplexed Random Access Channel (RACH) opportunities in a time resource.

30. The method according to any one of claims 17 to 20, wherein The size of the first resource allocation for PUSCH transmission of the msgA is different from the size of the second resource allocation for PUSCH transmission of the msgA.

31. The method according to any one of claims 17 to 20, wherein The two-step RA configuration is sent in the system information.

32. The method according to any one of claims 17 to 20, wherein For each of the first resource allocation and the second resource allocation for PUSCH transmission of the msgA, the two-step RA configuration indicates at least one of a modulation and coding scheme, the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the number of physical resource blocks.

33. A wireless device (22) for selecting resources for a two-step Random Access (RA) procedure, the wireless device (22) comprising a processing circuit (84), the processing circuit (84) being configured to cause the wireless device (22) to: Receiving, from a network node (16), a two-step RA configuration for a cell, the two-step RA configuration including: A first resource allocation for Physical Uplink Shared Channel (PUSCH) transmission of the first message msgA for the two-step RA procedure, the first resource allocation for PUSCH transmission of the msgA being associated with a first set of preambles; and a second resource allocation for PUSCH transmission of the msgA associated with a second set of preambles; Based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA, select one of the first resource allocation and the second resource allocation and one of the associated first set of preambles and the second set of preambles; And Use the selected one of the first resource allocation and the second resource allocation to send the PUSCH transmission of the msgA; Wherein the processing circuit (84) is configured to cause the wireless device (22) to select one of the first resource allocation and the second resource allocation and one of the associated first set of preambles and the second set of preambles by being configured to cause the wireless device (22) to perform the following operations: Compare the payload size of the PUSCH transmission of the msgA with a size threshold, the size threshold being associated with the first resource allocation and the second resource allocation of the two-step RA configuration; Compare the estimated downlink path loss with a path loss threshold, the path loss threshold being associated with the second set of preambles; When the payload size is greater than the size threshold and the estimated downlink path loss is less than the path loss threshold, select the second resource allocation and the associated second set of preambles; When the two-step RA process is initiated for a common control channel CCCH logical channel and the size of the CCCH service data unit SDU plus the media access control MAC sub-header is greater than the size threshold, select the second resource allocation and the associated second set of preambles; and otherwise, select the first resource allocation and the associated first set of preambles.

34. The wireless device (22) according to claim 33, wherein, The processing circuitry (84) is configured to cause the wireless device (22) to: select a preamble for the msgA transmission for the two-step RA process from one of the first set of preambles and the second set of preambles selected; and transmit the selected preamble of the msgA.

35. The wireless device (22) according to claim 33, wherein, The two-step RA configuration further includes the size threshold.

36. The wireless device (22) according to claim 35, wherein, the two-step RA configuration further includes the path loss threshold.

37. The wireless device (22) according to any one of claims 33 to 36, wherein, Each of the first resource allocation and the second resource allocation includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version.

38. The wireless device (22) according to claim 37, wherein, The processing circuitry (84) is configured to cause the wireless device (22) to further select one of the first resource allocation and the second resource allocation based on the respective modulation and coding schemes of the first resource allocation and the second resource allocation.

39. The wireless device (22) according to claim 37, wherein, The processing circuitry (84) is configured to cause the wireless device (22) to further select one of the first resource allocation and the second resource allocation based on the respective transmit power instructions of the first resource allocation and the second resource allocation.

40. The wireless device (22) according to claim 39, wherein, the two-step RA configuration further includes a transmit power threshold associated with the first set of preambles and the second set of preambles; and the processing circuitry (84) is configured to cause the wireless device (22) to select one of the first resource allocation and the second resource allocation and an associated one of the first set of preambles and the second set of preambles by being configured to perform the following: estimate the transmit power of the PUSCH transmission for transmitting the msgA on one of the first resource allocation and the second resource allocation; and select one of the first resource allocation and the second resource allocation based on whether the estimated transmit power meets the transmit power threshold.

41. The wireless device (22) according to any one of claims 33 to 36, wherein, The processing circuitry (84) is configured to cause the wireless device (22) to further select one of the first resource allocation and the second resource allocation based on whether the wireless device (22) is an ultra-reliable low-latency communication URLLC device.

42. The wireless device (22) according to any one of claims 33 to 36, wherein, The processing circuitry (84) is further configured to cause the wireless device (22) to: select at least one beam from among a plurality of beams in the cell; determine that the selected beam is associated with the two-step RA configuration; and use the two-step RA configuration associated with the selected beam to select one of the first resource allocation and the second resource allocation and an associated one of the first set of preambles and the second set of preambles.

43. The wireless device (22) according to claim 42, wherein, The processing circuit (84) is configured to cause the wireless device (22) to select the at least one beam by causing the wireless device (22) to perform the following operations: select the at least one beam from among the plurality of beams in the cell based on a reference signal received power (RSRP) threshold; and The at least one selected beam includes at least one of the following: an SSB beam selected from among a plurality of synchronization signal block (SSB) beams in the cell; and a CSI-RS beam selected from among a plurality of channel state information reference signal (CSI-RS) beams in the cell.

44. The wireless device (22) according to claim 41, wherein, The two-step RA configuration is included in one of the following: a PUSCH configuration mapped to the at least one selected beam, the PUSCH configuration indicating the first resource allocation and the second resource allocation for PUSCH transmission of the msgA; a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to the at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with the at least one selected beam; and a PUSCH configuration and a physical random access channel (PRACH) configuration, the PRACH configuration being mapped to the at least one selected beam, and the PUSCH configuration being based on a logical channel for which the two-step RA procedure is performed.

45. The wireless device (22) according to claim 42, wherein, The at least one selected beam is mapped to a plurality of frequency-multiplexed random access channel (RACH) opportunities in one time resource.

46. The wireless device (22) according to any one of claims 33 to 36, wherein, The size of the first resource allocation for PUSCH transmission of the msgA is different from the size of the second resource allocation for PUSCH transmission of the msgA.

47. The wireless device (22) according to any one of claims 33 to 36, wherein, Receive the two-step RA configuration in system information.

48. The wireless device (22) according to any one of claims 33 to 36, wherein, The processing circuit (84) is further configured to cause the wireless device (22) to: determine a set of information bits for PUSCH transmission of the msgA, the set of information bits corresponding to the payload; determine a transport block size according to at least one of a modulation and coding scheme, a number of orthogonal frequency division multiplexing (OFDM) symbols, and a number of physical resource blocks indicated in one of the first resource allocation and the second resource allocation in the two-step RA configuration; when the set of information bits is less than or equal to the transport block size, send a PUSCH transmission of the msgA including the information bits; and when the set of information bits is greater than the transport block size, remove at least one bit from the set of information bits based on the priority of the logical channel for which the two-step RA procedure is performed.

49. A network node (16) configured to communicate with a wireless device (22), the network node (16) including a processing circuit (68), the processing circuit (68) being configured to cause the network node (16) to: send to the wireless device (22) a two-step random access (RA) configuration for a cell, the two-step RA configuration including: The first resource allocation for physical uplink shared channel (PUSCH) transmission of the first message msgA for a two-step random access (RA) procedure, the first resource allocation for the PUSCH transmission of the msgA is associated with a first preamble set; and A second resource allocation for the PUSCH transmission of the msgA associated with a second preamble set; And Receiving the PUSCH transmission of the msgA according to one of the first resource allocation and the second resource allocation, one of the first resource allocation and the second resource allocation and one of the associated first preamble set and the second preamble set are based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA; Wherein, the processing circuit (68) is configured to cause the network node (16) to receive the PUSCH transmission of the msgA by being configured to cause the network node (16) to perform the following operations: When the payload size is greater than a size threshold associated with the first resource allocation and the second resource allocation of the two-step RA configuration and the estimated downlink path loss is less than a path loss threshold associated with the second preamble set, receiving the PUSCH transmission of the msgA according to the second resource allocation; When the two-step RA procedure is initiated for a common control channel (CCCH) logical channel and the size of the CCCH service data unit (SDU) plus the media access control (MAC) sub-header is greater than the size threshold, receiving the PUSCH transmission of the msgA according to the second resource allocation; and Otherwise, receiving the PUSCH transmission of the msgA according to the first resource allocation.

50. The network node (16) according to claim 49, wherein, The processing circuit (68) is configured to cause the network node (16) to: Receive a preamble of the msgA transmission of the two-step RA procedure, the preamble being from one of the first preamble set and the second preamble set based on the two-step RA configuration and the payload size of the PUSCH transmission of the msgA.

51. The network node (16) according to claim 49, wherein, The two-step RA configuration further includes the size threshold.

52. The network node (16) according to claim 51, wherein, The two-step RA configuration further includes the path loss threshold.

53. The network node (16) according to any one of claims 49 to 52, wherein, Each of the first resource allocation and the second resource allocation includes at least one of the following: time resource; frequency resource; modulation and coding scheme; transmit power instruction; and redundancy version.

54. The network node (16) according to claim 53, wherein, One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on the corresponding modulation and coding schemes of the first resource allocation and the second resource allocation.

55. The network node (16) according to claim 53, wherein, One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on the corresponding transmit power instructions of the first resource allocation and the second resource allocation.

56. The network node (16) according to claim 55, wherein, The two-step RA configuration further includes a transmit power threshold associated with the first preamble set and the second preamble set; and One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA and an associated one of the first preamble set and the second preamble set are based on whether the estimated transmit power meets the transmit power threshold.

57. The network node (16) according to any one of claims 49 to 52, wherein, One of the first resource allocation and the second resource allocation for receiving the PUSCH transmission of the msgA is further based on whether the wireless device (22) is an ultra-reliable low-latency communication URLLC device.

58. The network node (16) according to any one of claims 49 to 52, wherein, Receive the PUSCH transmission of the msgA according to the two-step RA configuration associated with at least one beam in the cell selected by the wireless device (22).

59. The network node (16) according to claim 58, wherein, The two-step RA configuration includes a reference signal received power RSRP threshold, and the at least one beam in the cell is selected by the wireless device (22) based on the RSRP threshold; and The at least one selected beam includes at least one of the following: An SSB beam selected from a plurality of synchronization signal block SSB beams in the cell; And A CSI-RS beam selected from a plurality of channel state information reference signal CSI-RS beams in the cell.

60. The network node (16) according to claim 58, wherein, The two-step RA configuration is included in one of the following: A PUSCH configuration mapped to at least one selected beam, the PUSCH configuration indicating the first resource allocation and the second resource allocation for the PUSCH transmission of the msgA; A PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being mapped to the PRACH configuration associated with at least one selected beam; And A PUSCH configuration and a physical random access channel PRACH configuration, the PRACH configuration being mapped to at least one selected beam, and the PUSCH configuration being based on the logical channel for which the two-step RA process is performed.

61. The network node (16) according to claim 58, wherein, The at least one selected beam is mapped to a plurality of frequency-multiplexed random access channel RACH opportunities in a time resource.

62. The network node (16) according to any one of claims 49 to 52, wherein, The size of the first resource allocation for the PUSCH transmission of the msgA is different from the size of the second resource allocation for the PUSCH transmission of the msgA.

63. The network node (16) according to any one of claims 49 to 52, wherein, The two-step RA configuration is sent in the system information.

64. The network node (16) according to any one of claims 49 to 52, wherein For each of the first resource allocation and the second resource allocation for the PUSCH transmission of the msgA, the two-step RA configuration indicates at least one of a modulation and coding scheme, the number of orthogonal frequency division multiplexing OFDM symbols, and the number of physical resource blocks.

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