Patent Description:
The standardization organization Third Generation Partnership Project (3GPP) is currently in the process of specifying a new Radio Interface called <NUM> New Radio (<NUM> NR) as well as a Next Generation Packet Core Network (NG-CN or NGC). The <NUM> NR will have three main components: a <NUM> Access Network (<NUM>-AN), a <NUM> Core Network (5GC), and a User Equipment (UE). In order to facilitate the enablement of different data services and requirements, the elements of the 5GC, also called Network Functions, have been simplified with some of them being software based so that they could be adapted according to need.

3GPP Draft R2-<NUM>, <CIT> and <CIT> are related prior art documents.

The example embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings.

A wireless communication device may transmit, in a random access (RA) procedure, a RA preamble and a corresponding uplink channel payload to a wireless communication node. The wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload through an uplink grant, responsive to a failure of the transmitted uplink channel payload for the wireless communication node.

In some embodiments, the wireless communication device from the wireless communication node may receive a fallback RA response (RAR) including the uplink grant. The RA procedure may include a contention free RA (CFRA) procedure.

In some embodiments, the wireless communication device may establish a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer. The corresponding uplink channel payload may be based on the MsgA buffer. In some embodiments, the wireless communication device may re-transmit to the wireless communication node. The corresponding uplink channel payload may use the MAC PDU.

In some embodiments, the wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload only once. The uplink grant may be from a fallback RA response (RAR).

In some embodiments, the wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload through the uplink grant. The scheduling of uplink channel payload based on the uplink grant may correspond to a new data indicator (NDI) with an initial NDI value. The uplink grant may be from a fallback RA response (RAR). In some embodiments, the wireless communication device may receive, from the wireless communication node, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). The C-RNTI may include a current NDI value. The wireless communication device may retransmit, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload according to whether the current NDI value differs from the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled.

In some embodiments, when the current NDI value matches the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication device may retransmit the corresponding uplink channel payload that is buffered in a buffer of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the current NDI value differs from the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled , the wireless communication device may initiate a transmission based on a new scheduling of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication device may maintain or keep a hybrid automatic repeat request (HARQ) buffer from the transmitting of the RA preamble and the corresponding uplink channel payload. The HARQ buffer may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmitting of the RA preamble and the corresponding uplink channel payload may be the last random access attempt and may be made using CFRA resources. In some embodiments, the wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload in the MAC PDU. In some embodiments, the wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload using a redundant version (RV). The RV may be indicated in a fallback RA response (RAR).

In some embodiments, the wireless communication device may retransmit, to the wireless communication node corresponding to a new data indicator (NDI) with an initial value, the corresponding uplink channel payload in the MAC PDU. In some embodiments, the wireless communication device may retransmit, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

In some embodiments, the wireless communication device may retransmit, responsive to the failure of the retransmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload through an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). In some embodiments, when the NDI is unchanged in value relative to the initial value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication device may retransmit the corresponding uplink channel payload that is buffered in a buffer of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the NDI is changed in value relative to the initial value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication device may initiate a transmission based on the new scheduling of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication device may determine an NDI value as the previous new data indicator (NDI) value of a transmission of a hybrid automatic repeat request (HARQ) process occurring prior to the transmitting of the RA preamble and the corresponding uplink channel payload to the wireless communication node using the same HARQ process. In some embodiments, the wireless communication device may receive, from the wireless communication node, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). The downlink channel may include a current NDI value. In some embodiments, the wireless communication device may re-transmit, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload according to whether the current NDI value differs from the previous NDI value. In some embodiments, the uplink grant may be from a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

In some embodiments, the wireless communication device corresponding to a new data indicator (NDI) with an initial value may transmit the RA preamble and the corresponding uplink channel payload to the wireless communication node. The corresponding uplink channel payload may be in the MAC PDU. In some embodiments, the wireless communication device may retransmit to the wireless communication node, responsive to the failure of the transmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

In some embodiments, when the NDI is unchanged in value relative to the initial value, the wireless communication device may retransmit the corresponding uplink channel payload that is buffered in a buffer of hybrid automatic repeat request (HARQ) process. In some embodiments, the wireless communication device may maintain a HARQ buffer from the transmitting of the RA preamble and the corresponding uplink channel payload. The HARQ buffer may include a medium access control (MAC) protocol data unit (PDU). The wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload in the MAC PDU.

In some embodiments, when the NDI is changed in value relative to the initial value, the wireless communication device may initiate a transmission based on a new scheduling of hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication device corresponding to a new data indicator (NDI) with an initial value may transmit the RA preamble and the corresponding uplink channel payload to the wireless communication node. The corresponding uplink channel payload may be in the MAC PDU. In some embodiments, responsive to receiving an uplink grant addressed to the C-RNTI, and to the RA procedure being a contention free RA (CFRA) procedure, the wireless communication device may retransmit the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

At least one aspect is directed to a system, method, apparatus, or a computer-readable medium. A wireless communication node in a random access (RA) procedure may receive a RA preamble and a corresponding uplink channel payload from a wireless communication device. The wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload through an uplink grant, responsive to a failure of the transmitted uplink channel payload for the wireless communication node.

In some embodiments, the wireless communication node may transmit, to the wireless communication device, a fallback RA response (RAR) including the uplink grant. The RA procedure may include a contention free RA (CFRA) procedure. In some embodiments, the wireless communication node may cause the wireless communication device to establish a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer. The corresponding uplink channel payload may be based on the MsgA buffer. In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload using the MAC PDU. In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload only once. The uplink grant may be from a fallback RA response (RAR).

In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload through the uplink grant. The scheduling of the uplink channel payload based on the uplink grant may correspond to a new data indicator (NDI) with an initial NDI value. The uplink grant may be from a fallback RA response (RAR). In some embodiments, the wireless communication node may transmit, to the wireless communication device, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). The downlink channel may include a current NDI value. The wireless communication node may re-receive, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, from the wireless communication device, the corresponding uplink channel payload according to whether the current NDI value differs from the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled.

In some embodiments, when the current NDI value matches the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload that is buffered in a buffer of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the current NDI value differs from the initial NDI value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication node may cause the wireless communication device to initiate a transmission based on a new scheduling of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication node may cause the wireless communication device to maintain or keep a hybrid automatic repeat request (HARQ) buffer from the transmitting of the RA preamble and the corresponding uplink channel payload. The HARQ buffer may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmitting of the RA preamble and the corresponding uplink channel payload may be the last random access attempt and may be made using CFRA resources. In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload in the MAC PDU. In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload using a redundant version (RV). The RV may be indicated in a fallback RA response (RAR).

In some embodiments, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload in the MAC PDU. The wireless communication node may correspond to a new data indicator (NDI) with an initial value. In some embodiments, the wireless communication node may re-receive, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, from the wireless communication device, the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

In some embodiments, the wireless communication node may re-receive, responsive to the failure of the retransmitted uplink channel payload for the wireless communication node, from the wireless communication device, the corresponding uplink channel payload through an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

In some embodiments, when the NDI is unchanged in value relative to the initial value, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload that is buffered in a buffer of hybrid automatic repeat request (HARQ) process.

In some embodiments, when the NDI is unchanged in value relative to the initial value, the wireless communication node may cause the wireless communication device to initiate the corresponding uplink channel payload that is buffered in a buffer of hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication node may re-receive, responsive to the failure of the retransmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload through an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). In some embodiments, when the NDI is unchanged in value relative to the initial value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication node may re-receive the corresponding uplink channel payload that is buffered in a buffer of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the NDI is changed in value relative to the initial value (or the previous NDI value) of the same HARQ process that is scheduled, the wireless communication node may cause the wireless communication device to initiate a transmission based on the new scheduling of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication node may cause the wireless communication device to determine an NDI value as the previous a new data indicator (NDI) of a transmission of a hybrid automatic repeat request (HARQ) process occurring prior to the transmitting of the RA preamble and the corresponding uplink channel payload to the wireless communication node using the same HARQ process. In some embodiments, the wireless communication node may transmit, to the wireless communication device, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). The C-RNTI may include a current NDI value. In some embodiments, the wireless communication node may re-receive, responsive to a failure of the retransmitted uplink channel payload for the wireless communication node, from the wireless communication device, the corresponding uplink channel payload according to whether the current NDI value differs from the previous NDI value. In some embodiments, the uplink grant may be from a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

In some embodiments, the wireless communication node may receive, from the wireless communication device, the RA preamble and the corresponding uplink channel payload to the wireless communication node, he corresponding uplink channel payload in the MAC PDU. The wireless communication node may correspond to a new data indicator (NDI) with an initial value. In some embodiments, the wireless communication node may re-receive, from the wireless communication device, responsive to the failure of the transmitted uplink channel payload for the wireless communication node, the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

In some embodiments, the wireless communication node may cause the wireless communication device to maintain or keep a HARQ buffer from the transmitting of the RA preamble and the corresponding uplink channel payload. The HARQ buffer may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmitting of the RA preamble and the corresponding uplink channel payload may be the last random access attempt and may be made using CFRA resources. In some embodiments, the wireless communication device may retransmit, to the wireless communication node, the corresponding uplink channel payload in the MAC PDU.

In some embodiments, when the NDI is changed in value relative to the initial value, the wireless communication node may cause the wireless communication device to initiate a transmission based on a new scheduling of hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to protocol.

In some embodiments, the wireless communication node may receive, from the wireless communication device, the RA preamble and the corresponding uplink channel payload to the wireless communication node, the corresponding uplink channel payload in the MAC PDU. The wireless communication node may correspond to a new data indicator (NDI) with an initial value. In some embodiments, responsive to receiving an uplink grant addressed to the C-RNTI, and to the RA procedure being a contention free RA (CFRA) procedure, the wireless communication node may re-receive, from the wireless communication device, the corresponding uplink channel payload according to whether the NDI has changed in value relative to the initial value.

The following acronyms are used throughout the present disclosure:.

<FIG> illustrates a block diagram of an example wireless communication system <NUM> for transmitting and receiving wireless communication signals (e.g., OFDM/OFDMA signals) in accordance with some embodiments of the present solution. The system <NUM> may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, system <NUM> can be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment such as the wireless communication environment <NUM> of <FIG>, as described above.

The present systems and methods address how to configure and select RA preamble and physical uplinked shared channel (PUSCH) payload messages (sometimes referred herein as MsgA) transmission resource for a UE (e.g., UE <NUM>) in different states. The states may be separate for the UE in IDLE/INACTIVE mode and for the UE in connected mode. In addition, the present systems and methods address how to handle a situation in which a network (NW) side appliance (e.g., BS <NUM>) has successfully decode preamble but fails to receive or decode corresponding PUSCH payload in case of <NUM>-step RA type Random Access procedure.

Under Random Access (RA) procedures, <NUM>-step RA type and <NUM>-step RA type may be supported. In some cases, <NUM>-step RA type RA channel (RACH) can be referred as type <NUM> and a <NUM>-step RA type RACH can be referred as type <NUM> RACH procedure, or vice versa. For each type of RACH procedure, both contention based RACH and contention free RACH can be applied, which in total can leads to four kind of RACH procedure, contention based RA (CBRA) with <NUM>-step RA type (e.g., sequence 300A as depicted in <FIG>), contention free (CFRA) with <NUM>-step RA type (e.g., sequence 300C as depicted in <FIG>), CBRA with <NUM>-step RA type (e.g., sequence 300B as depicted in <FIG>), and CFRA with <NUM>-step RA type (e.g., sequence 300D as depicted in <FIG>).

The general procedure for <NUM>-step RA type Random Access procedure can be summarized as follows. First, UE may transmit a MsgA to NW side. The MsgA may include transmission of RA preamble and PUSCH payload. The UE may receive a RA response sent by NW in response to the receipt of the MsgA.

The UE can receive multiple sets of RACH resource configurations for <NUM>-step RA type RA procedure. The UE may select the <NUM>-step RACH resource based on pre-defined rules. For each set of <NUM>-step RACH resource may include at least one of the following:.

the multiple sets of RACH resource configurations for <NUM>-step RA type RA procedure may be configured from NW to UE by broadcast system information, by dedicated RRC signaling.

The configuration of <NUM>-step CFRA resource may contain at least one of the following two parts:.

In some embodiments, the preamble for <NUM>-step CFRA can be reserved from either the preamble resource pool for <NUM>-step CBRA (i.e. share the RO configuration of <NUM>-step CBRA), or reserved from a separate preamble resource pool (i.e. have separate RO configuration of <NUM>-step CBRA). To enable the configuration of separate preamble resource pool, a different information element (IE) (e.g. RACH-ConfigGenericTwoStepRA-r16 may be allowed) different from the one used for configuration of <NUM>-step CBRA resource). In some embodiment, if the RACH-ConfigGenericTwoStepRA-r16 is absent for <NUM>-step CFRA, then the configuration for <NUM>-step CBRA will be reused.

In some embodiments, the method for the configuration of contention-free preamble for each SSB/CSI-RS in <NUM>-step CBRA as specified in protocol can be reused for <NUM>-step CFRA:.

In some embodiments, the PUSCH resource for <NUM>-step CFRA can be configured in dedicated signaling. In some embodiments, the same IE used for the configuration for MsgA PUSCH resources for <NUM>-step CBRA can be reused for the configuration of MsgA PUSCH resource for <NUM>-step CFRA, which including at least one of the following:.

For the <NUM>-step CFRA, once the PUSCH resource pool is configured, the PUSCH resource unit for each preamble reserved for each SSB/CSI-RS can be determined using various techniques.

In some embodiments, the mapping rule defined for <NUM>-step CBRA (e.g. as specified in protocol) may be reused to determine the mapping between each preamble and the PUSCH resource unit The mapping rule between preamble and PUSCH resource unit defined in technical specification <NUM> for <NUM>-step CBRA can be reused. With the mapping rule, each preamble reserved for CFRA may be mapped to a PUSCH resource unit. To enable this alternative, the number of preambles reserved for <NUM>-step CFRA may be provided, and all the preambles reserved for <NUM>-step CFRA may be considered in the mapping between preamble and PUSCH resource unit, even the preamble will not be reserved for the concerned UE. To indicate the preambles reserved for <NUM>-step CFRA, the following parameters may be used:.

As depicted in <FIG>, depicted is an example 300E of an abstract schematic of a preamble allocated in different SSB/CSI resources. The UE may deduct the allocation of the preamble based on the resource configuration received. The msgA-PreambleStartIndex may be set to <NUM>, and the msgA-TotalNumberOfCFRA-Preambles may be set to <NUM>. With these two parameters, the preambles <NUM>-<NUM> and preambles <NUM>-<NUM> may be considered as reserved for <NUM>-step CFRA, and these preambles reserved may be mapped to the PUSCH resource unit provided by MsgA-PUSCH-Resource-r16 in signaling of a CFRA resource configuration. With the mapping between preamble and PUSCH resource unit, once a preamble may be reserved for one SSB or CSI-RS, the PUSCH resource unit mapped to the preamble may be reserved as well.

In some embodiments, the PUSCH resource unit index for each SSB/CSI-RS may be explicitly configured. A PUSCH resource unit index may be explicitly allocated for each SSB/CSI-RS. The PUSCH resource unit index may be numbered based on the same order (e.g., as defined in technical specs <NUM>) for the mapping between PUSCH resource unit and preamble (e.g., first, in increasing order of frequency resource indexes; second, in increasing order of DMRS indexes within a PUSCH occasion; and third, in increasing order of time resource indexes; fourth, in increasing order of indexes for PUSCH slots). To enable this alternative, a new IE msgA-PRUIndex may be introduced and some description will be introduced in <NUM> to specify the meaning of msgA-PRUIndex.

An example on ASN. <NUM> for configuration of CFRA resource for <NUM>-step RA is given as follows. The information element (IE) RACH-ConfigDedicated may be used to specify the dedicated random access parameters. <IMG>
<IMG>
<IMG>.

In some embodiments, the pre-defined rules can define or specify that in the case when multiple <NUM>-step RACH resource sets are configured, the UE is to select the <NUM>-step RACH resource based on the trigger of RA procedure. The RA triggers may include at least one of the following:.

The triggers alone or different combination of RA triggers can be linked to different sets of <NUM>-step RA resource configured, and UE based on the RA trigger to select the corresponding <NUM> step RA resource set. For example, for the RA procedure triggered by RRC establishment, RRC re-establishment, RRC resume, the UE is to select the <NUM>-step RACH resource set <NUM>. For the RA procedure triggered by any other reason, the UE is to select the <NUM>-step RACH resource set <NUM>.

In some embodiments, the pre-defined rules may define or specify that in the case when multiple <NUM>-step RACH resource set are configured, then UE is to select the <NUM>-step RACH resource set based on the content of MsgA payload. For example:.

In some embodiments, the pre-defined rules may define or specify that in the case when multiple <NUM>-step RACH resource set are configured, then UE is to select the <NUM>-step RACH resource set based on whether there is valid C-RNTI (cell radio network temporary identifier) stored for the cell. If there is valid C-RNTI stored on UE side, then the UE is to use <NUM>-step RACH resource set <NUM>. Otherwise, the UE is to use <NUM>-step RACH resource set <NUM>.

In some embodiments, the pre-defined rules may define or specify that UE is to select the <NUM>-step RACH resource based on the presence of <NUM>-step RACH resource for CONNECTED, or dedicated contention based <NUM>-step RACH resources. For example, if <NUM>-step CBRA resource is configured in BWP-UplinkDedicated for the current BWP, then the dedicated <NUM>-step CBRA resource may be used instead of the resource configured in common resource.

In addition, different combination of above alternative can be used, or used together with the selection rules that is specified in protocol.

The UE may retransmit MsgA PUSCH payload in case NW has successfully decode preamble but fails to receive or decode the corresponding PUSCH payload, and may take one of the following measures.

In some embodiments, the UE may perform a transmission or retransmission of MsgA PUSCH payload through UL grant received in fallback Random Access Response (RAR) if the fallback RAR is received in responsive to a MsgA transmission that is made on CFRA resource. In this case, if received MsgB contains fallback RAR with the same preamble index that is transmitted in MsgA, then the UE may process the received Timing Advance Command. The UE may ignore the received TC-RNTI (temporary C-RNTI) (because it already has a C-RNTI), and may identify the RA procedure as successfully completed and stop MsgB response window. UE may retransmit the MsgA PUSCH payload according following alternatives.

In some embodiments, for the UL grant in fallback RAR, the UE may generate a new MAC PDU based on the MsgA buffer (e.g., in the physical layer). For example, if RA is considered completion after reception of fallback RAR and CFRA resource is used for transmission of MsgA, the MsgA buffer will not be flushed right away. The UE may first generate a new MAC PDU based on the MsgA buffer. In some embodiments, the new generated MAC PDU may be put in HARQ process <NUM> for transmission, and may be transmitted based on the UL grant received in the fallback RAR in responsive to MsgA transmission made on CFRA resource. Aafter the transmission of the MAC PDU in HARQ process <NUM>, the UE may keep the HARQ buffer of HARQ process <NUM>. In some embodiments, the new generated MAC PDU may be put in HARQ process <NUM>. In some embodiments, the MsgA PUSCH payload may be retransmitted by the UE once using the UL grant received in fallback RAR.

In some embodiments, considering the retransmission of PUSCH payload using UL grant indicated in fallback RAR as described above might fail again since in this case RA has already completed, the UE can retransmit the MsgA payload buffered in HARQ process <NUM> based on scheduling on PDCCH addressed to C-RNTI. In this case, one initial new data indicator (NDI) value (<NUM> or <NUM>) may be used for the MsgA PUSCH payload transmission scheduled by UL grant in fallback RAR, and UE based on whether NDI may be toggled to decide whether this is a new scheduling of HARQ process <NUM> (e.g., scheduling of transmission of new data) or whether to retransmit the MsgA payload stored in HARQ buffer of HARQ process <NUM>.

The initial NDI value described above may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling or indicated in fallback RAR (e.g. using the bits reserved for TC-RNTI). In some embodiments, if subsequent scheduling made on PDCCH addressed to C-RNTI for HARQ process <NUM> is received after retransmission of MsgA PUSCH payload using the UL grant received in fallback RAR, the UE may compare the NDI value received in the PDCCH with the NDI value set for previous transmission of the same HARQ process prior to the MsgA transmission. If the NDI is toggled (e.g.,, different from the previous NDI value), then UE may perform new transmission of HARQ process <NUM> (e.g., transmission of new data in HARQ process <NUM>) according to the scheduling configuration received in the PDCCH. Else, if the NDI is not toggled (e.g., the same as previous NDI value), UE may perform retransmission of HARQ process <NUM> according to the scheduling configuration received in the PDCCH.

For example, a scheduling of HARQ process <NUM> may be made with the NDI value set as "<NUM>", and after which the UE may initiate a <NUM>-step RA type Random Access procedure using CFRA resource (e.g., as depicted in <FIG>). After transmission of MsgA if UE receives fallback RAR sent from network for scheduling MsgA PUSCH payload retransmission, the UE may transmit MsgA PUSCH payload in HARQ process <NUM> according to the UL grant indicated in fallback RAR. Since the transmission scheduled by UL grant in fallback RAR will not reset NDI value, then the NDI of HARQ <NUM> in this case is still "<NUM>". After which, if the NDI of subsequent scheduling of HARQ process <NUM> made on PDCCH addressed to C-RNTI is "<NUM>", the UE may compare the NDI of the subsequent scheduling with the NDI value of HARQ process <NUM> prior to MsgA transmission (which is <NUM> in this example), and the NDI is not toggled. The UE may perform retransmission of HAQR process <NUM> else if the NDI received is "<NUM>", meaning the NDI is toggled then UE will consider this is a scheduling of a new transmission.

In some embodiments, the HARQ buffer may be kept or maintained and the UL grant from fallback RAR may be used to process the HARQ retransmission for HARQ process <NUM>. In some embodiments, UE may keep the HARQ buffer of HARQ process (e.g., HARQ process <NUM>) that is used for transmission of the MAC PDU in MsgA buffer (or Msg3 buffer) after RA is completed and the last RA attempt is made on <NUM>-step CFRA resource as described above. The UE may use the UL grant received in the fallback RAR for retransmission of MAC PDU buffered in HARQ process <NUM>. In some embodiments, after retransmission of HARQ process <NUM> using the UL grant indicated in fallback RAR as described above, the UE may keep or maintain the HARQ buffer of corresponding HARQ process (e.g., HARQ process <NUM>).

In some embodiments, if the UL grant is received in fallback RAR, and the previous MsgA transmission of the same HARQ process may be transmitted through <NUM>-step CFRA resource, the UE may consider the NDI of the corresponding HARQ process as not toggled. Then the UE may perform the HARQ retransmission of HARQ process <NUM>.

Furthermore, the RV version used for MsgA payload retransmission as described above can be fixed as RV0, or predefined in protocol (e.g., UE use the pre-defined RV pattern for MsgA payload retransmission scheduled by UL grant in fallback RAR and following retransmission scheduled by PDCCH addressed to C-RNTI is needed, ignoring the RV indicated in the PDCCH) or as indicated in the fallbackRAR (e.g., using the reserved bits for TC-RNTI).

In some embodiments, if subsequent retransmission of MsgA payload would be needed after HARQ retransmission of HARQ process <NUM> using the UL grant in fallback RAR in responsive to MsgA transmission of the last RA attempt made on CFRA resources, the UE can be scheduled with PDCCH addressed to C-RNTI. In this case, an initial NDI value (<NUM> or <NUM>) can be used as the NDI value of the first MsgA transmission (or of the MsgA payload retransmission scheduled by fallback RAR UL grant ) for NDI comparison. The initial NDI value may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling or indicated in fallback RAR (e.g. using the bits reserved for TC-RNTI). For example, if fallback RAR for MsgA payload retransmission is received and UE assumes NDI of the previous MsgA transmission made on CFRA resource is "<NUM>", then the NDI of the UL grant received in fallback RAR for retransmission of MsgA payload may be "<NUM>". If following UL grant is received on PDCCH for the C-RNTI is for the same HARQ process and the NDI is "<NUM>" (e.g., NDI is not toggled), then the UE may perform the retransmission using configuration as indicated in the received PDCCH. Otherwise, if the NDI value is "<NUM>" (e.g., NDI is toggled), then the UE may perform the new HARQ transmission as specified in the protocol.

In some embodiments, if subsequent retransmission of MsgA payload is to be used after HARQ retransmission of HARQ process <NUM> using the UL grant in fallback RAR received in responsive to MsgA transmission of the last RA attempt made on CFRA resources as discussed above, the UE can be scheduled with PDCCH addressed to C-RNTI. For example, after retransmission of HARQ process <NUM> using the UL grant indicated in fallback RAR as described above, the UE may keep or maintain the HARQ buffer of HARQ process <NUM>. And UE may receive PDCCH addressed to C-RNTI for scheduling of HARQ process <NUM>. The UE may compare the NDI value received in first scheduling on PDCCH addressed to C-RNTI after MsgA transmission made on <NUM>-step CFRA resource with the NDI value set for previous transmission of the same HARQ process prior to the MsgA transmission. In another words, the NDI set for HARQ process <NUM> prior to MsgA transmission made on CFRA resource may be used for NDI comparison of subsequent scheduling on PDCCH addressed to C-RNTI after MsgA transmission on CFRA resource or subsequent MsgA payload transmission on UL grant indicated in fallback RAR if needed. If the NDI is toggled (i.e., differ from the previous NDI value), then the UE may perform new transmission of HARQ process <NUM> (e.g., UE flushes HARQ process <NUM> buffer, and transmits new data in HARQ process <NUM>) according to the scheduling configuration received in the PDCCH, else if the NDI is not toggled (i.e., the same as previous NDI value), the UE may perform retransmission of HARQ process <NUM> according to the scheduling configuration received in the PDCCH.

For example, a scheduling of HARQ process <NUM> may be made with the NDI value set as "<NUM>", and after which UE initiate a <NUM>-step RA type Random Access procedure using CFRA resource. After transmission of MsgA, if the UE receives fallback RAR sent from network for scheduling MsgA PUSCH payload retransmission, the UE may transmit MsgA PUSCH payload in HARQ process <NUM> according to the UL grant indicated in fallback RAR. After which, if the NDI of subsequent scheduling of HARQ process <NUM> made on PDCCH addressed to C-RNTI is "<NUM>", the UE may compare the NDI value of the subsequent scheduling with the NDI value of HARQ process <NUM> prior to MsgA transmission (which is <NUM> in this example), and the NDI is not toggled, thus UE will perform retransmission of HAQR process <NUM> else if the NDI received is "<NUM>", meaning the NDI is toggled than UE will consider this is a scheduling of a new transmission.

In some embodiments, an NDI indication and the RV can be included in fallback RAR for <NUM>-step CFRA case (using the reserved bits for TC-RNTI). Based on the NDI indicated, the UE may determine either to retransmit the MAC PDU in HARQ process <NUM> using the UL grant in fallback RAR or to generate a new MAC PDU for the UL grant in fallback RAR.

In some embodiments, UE may consider the UL grant in fallback RAR as the UL grant for the new transmission of MsgA buffer (or Msg3 buffer). For example, RV <NUM> and HARQ process <NUM> may be used for transmission of MsgA payload (e.g., as defined in the protocol). Furthermore, if subsequent retransmission is to occur, the retransmission can be scheduled by PDCCH addressed to C-RNTI. In this case an initial value (<NUM> or <NUM>) may be used for the NDI of the new transmission of MsgA buffer (Msg3 buffer) scheduled by UL grant in fallback RAR for NDI comparison. The NDI value may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling or indicated in fallbackRAR (e.g. using the bits reserved for TC-RNTI).

In some embodiments, after retransmission of HARQ process <NUM> using the UL grant indicated in fallback RAR as described above, the UE may keep or maintain the HARQ buffer of corresponding HARQ process (e.g., HARQ process <NUM>). Furthermore, if subsequent scheduling made on PDCCH addressed to C-RNTI for HARQ process used for MsgA transmission (e.g. HARQ process <NUM>) is received after retransmission of MsgA PUSCH payload using the UL grant received in fallback RAR in responsive to MsgA transmission of the last RA attempt made on CFRA resources, the UE may compare the NDI value received in the PDCCH with the NDI value set for previous transmission of the same HARQ process prior to the MsgA transmission. If the NDI is toggled (i.e., differ from the previous NDI value), then the UE may perform new transmission of HARQ process <NUM> (e.g., transmission of new data in HARQ process <NUM>) according to the scheduling configuration received in the PDCCH. Otherwise, if the NDI is not toggled (i.e., the same as previous NDI value), the UE may perform retransmission of HARQ process <NUM> according to the scheduling configuration received in the PDCCH.

For example, a scheduling of HARQ process <NUM> may be made with the NDI value set as "<NUM>", and after which UE initiate a <NUM>-step RA type Random Access procedure using CFRA resource. After transmission of MsgA if the UE receives fallback RAR sent from network for scheduling MsgA PUSCH payload retransmission, the UE may transmit MsgA PUSCH payload in HARQ process <NUM> according to the UL grant indicated in fallback RAR. After which, if the NDI of subsequent scheduling of HARQ process <NUM> made on PDCCH addressed to C-RNTI is "<NUM>", UE may compare the NDI of the subsequent schedule with the NDI value of HARQ process <NUM> prior to MsgA transmission (which is <NUM> in this example), and the NDI is not toggled. The UE may perform retransmission of HARQ process <NUM> else if the NDI received is "<NUM>", meaning the NDI is toggled than UE will consider this is a scheduling of a new transmission.

In some embodiments, after the reception of fallback RAR in responsive of MsgA transmission made on CFRA resource, UE may continue the RA procedure, fallback to <NUM>-step CBRA. This may be the same behavior as the fallback RAR received after the transmission of MsgA though <NUM>-step CBRA resource.

In some embodiments, the UE may perform transmission or retransmission of MsgA PUSCH payload through UL grant received on PDCCH for the C-RNTI. If the previous uplink grant delivered to the HARQ entity for the same HARQ process was uplink grant determined for the contention free transmission of the MsgA,(e.g., as specified in the protocol) then value <NUM> (or value <NUM>) may be used as the NDI value for the previous MsgA transmission for the NDI comparison. The NDI value may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling. In some embodiments, if the RA has completed and the last RA attempt was made on CFRA resource, the HARQ buffer used for transmission of the MAC PDU in the MSGA buffer(or Msg3 buffer) may be kept to allow UE performing HARQ retransmission.

In this case, the UE may determine whether this UL grant is for a new transmission or a retransmission by comparing the NDI value received in the PDCCH addressed to C-RNTI with the initial NDI value assigned for previous MsgA transmission. If the NDI received in the PDCCH scrambled by C-RNTI compared to the initial value of previous uplink grant is not toggled (e.g. is not changed), then they UE may identify that the PDCCH scrambled C-RNTI is a scheduling for retransmission, and UE may perform the retransmission of PUSCH payload based on the scheduling on PDCCH addressed to C-RNTI. Else if the NDI value received in the PDCCH is toggled (e.g. is changed), then UE will perform new transmission of HARQ process <NUM> (e.g., transmission of new data in HARQ process <NUM>) according to the scheduling configuration indicated in the PDCCH.

In some embodiments, Once a UL grant indicated in PDCCH addressed to C-RNTI is received, and the previous transmission of the same HARQ process may be MsgA transmission through CFRA resource, one initial NDI value (<NUM> or <NUM>) may be considered for the previous MsgA transmission. The NDI value may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling. The UE may determine whether this UL grant received is scheduled for a new transmission, or a retransmission, by comparing the NDI value received in the PDCCH with the NDI value considered for previous transmission. If the NDI received in the PDCCH scrambled by C-RNTI compared to the initial value of previous uplink grant is not toggled (e.g. is not changed), then UE may identify the PDCCH scrambled by C-RNTI is a scheduling for retransmission, and UE may perform the retransmission of PUSCH payload based on the scheduling on PDCCH addressed to C-RNTI. Else, if the NDI is toggled (e.g., is changed), the UE may perform a new transmission of the scheduled HARQ process (e.g., transmit new data in the HARQ process) according to the scheduling configuration received in the PDCCH. In this case if the RA has completed and the last RA attempt was made on CFRA resource, the HARQ buffer used for transmission of the MAC PDU in the MsgA buffer (or Msg3 buffer) may be kept to allow UE performing HARQ retransmission.

In some embodiments, if subsequent scheduling made on PDCCH addressed to C-RNTI for HARQ process <NUM> is received in responsive to MsgA transmission of the last RA attempt made on CFRA resources, the UE may compare the NDI value received in the PDCCH with the NDI value set for previous transmission of the same HARQ process prior to the MsgA transmission. If the NDI is toggled (i.e., differ from the previous NDI value), then UE may perform new transmission of HARQ process <NUM> (e.g., transmission of new data in HARQ process <NUM>) according to the scheduling configuration received in the PDCCH. Else, if the NDI is not toggled (i.e., the same as previous NDI value), the UE may perform retransmission of HARQ process <NUM> according to the scheduling configuration received in the PDCCH. In this case, if the RA has completed and the last RA attempt was made on CFRA resource, the HARQ buffer used for transmission of the MAC PDU in the MSGA buffer (or Msg3 buffer) may be kept to allow UE performing HARQ retransmission.

For example, a scheduling of HARQ process <NUM> may be made with the NDI value set as "<NUM>", and after which the UE may initiate a <NUM>-step RA type Random Access procedure using CFRA resource. After transmission of MsgA, UE may keep HARQ buffer used for transmission of the MAC PDU in MsgA buffer. if the NDI of subsequent scheduling of HARQ process <NUM> made on PDCCH addressed to C-RNTI is "<NUM>", the UE may compare the NDI of the subsequent scheduling with the NDI value of HARQ process <NUM> prior to MsgA transmission (which is <NUM> in this example), and the NDI is not toggled. The UE may perform retransmission of HARQ process <NUM> else if the NDI received is "<NUM>", meaning the NDI is toggled than UE will consider this is a scheduling of a new transmission, and may perform new transmission of HARQ process <NUM> (e.g., transmission of new data in HARQ process <NUM>) according to scheduling configuration indicated in the PDCCH.

In some embodiments, one initial value can be allocated for the NDI for the MsgA transmission, independent of whether the CFRA or CBRA resource is used for MsgA transmission. The initial value for the NDI can be "<NUM>" or "<NUM>". The NDI value may be pre-defined in protocol or broadcasted in system information, or signaled by dedicated signaling. If the previous uplink grant delivered to the HARQ entity for the same HARQ process was uplink grant determined as specified in the protocol for the contention free transmission of the MsgA or as specified in in the protocol for the contention based transmission of MsgA, and C-RNTI is included in MsgA, one initial value may be used as the NDI for the previous MsgA transmission for NDI comparison. In this case if the RA has completed, the HARQ buffer used for transmission of the MAC PDU in the MSGA buffer or Msg3 buffer may be kept for UE to perform the retransmission.

Some examples in any combination detailed above can be used for MsgA PUSCH payload retransmission in case preamble is successfully decoded while the corresponding PUSCH payload is not.

Referring now to <FIG>, depicted is a method <NUM> of transmitting MsgAs in RA procedures. The method <NUM> may be implemented or performed using any components described herein, such as the BS <NUM> or UE <NUM>. In overview, the method <NUM> may include CFRA configuration and CBRA configuration as discussed above. The method <NUM> may include communicating a RA preamble and payload (<NUM>). The method <NUM> may include recommunicating the payload (<NUM>). The method <NUM> may include communicating a response (<NUM>).

The method <NUM> may include communicating a RA preamble and payload (<NUM>). A wireless communication device (e.g., UE <NUM>) may send, provide, or transmit a random access (RA) preamble and a corresponding uplink channel payload to a wireless communication node (e.g., BS <NUM>) in a RA procedure. The wireless communication node may in turn identify, obtain, or receive the RA preamble and the corresponding uplink channel payload form the wireless communication device in the RA procedure. The RA preamble may be generated in accordance with RA procedure, and the transmission resource for a preamble may include at least one of the following: transmission resource in time domain, transmission resource in frequency domain, a transmission resource in code domain, a format, or a mapping relation between the preamble and the payload transmission resources, among others. The uplink channel payload may contain or include at least one of the following: C-RNTI, UE identity, MAC CE, BSR, CCCH message, DCCC messages, PHR, MAC SDU from DRB, beam management related information, or other parameters that to be transmitted via the uplink channel. The transmission resource for uplink channel payload may include: a location of payload transmission resource in time-domain, of payload transmission in frequency, of payload transmission resource in code domain (e.g., orthogonal code, non-orthogonal code, or other code in physical layer), and bandwidth used for transmission, among others. The mapping relationship may include the following flexibilities: a preamble transmission resources located in different random access channel occasions (ROs) can be mapped to the same payload transmission occasion with different payload transmission code; different preambles within one RO can be mapped to different payload transmission occasions (with the same or different payload transmission code); multiple UE using different preambles can mapped the same payload transmission resources; the same payload transmission code within the same payload transmission occasion); one preamble resources (a combination of preamble and RO) can be mapped to multiple payload transmission code within one payload transmission occasion to enable the multi-layer data transmission (e.g. MIMO); and a timing offset between preamble transmission resources and payload transmission resources can be different for different preamble transmission resources (e.g. the same or next time slot), among others.

In some embodiments, the wireless communication device may establish a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer. The corresponding uplink channel payload may be based on the MsgA buffer. The MAC PDU may include a bit string aligned in length (e.g., multiple of <NUM> bits), such as one or more of: a common control channel (CCCH) message, a dedicated control channel (DCCH) message, MAC service data unit (SDU), and MAC-CE, a C-RNTI, an inactive RNTI (I-RNTI), UE-ID, buffer status report (BSR), a power headroom report (PDR), a beam measurement result, and a beam failure indication, among others. The MAC PDU may be established while in communication with the wireless communication node. Each MsgA may include the RA preamble and the corresponding uplink channel payload. In some embodiments, the wireless communication node may cause the wireless communication device to establish the MAC PDU based on the MsgA buffer. In some embodiments, the corresponding uplink channel payload may be in the MAC PDU.

In some embodiments, the wireless communication device may maintain (or keep) a hybrid automatic repeat request (HARQ) buffer from the transmission of the RA preamble and the corresponding uplink payload that is made on CFRA resource and it is the transmission of the last RA attempt. The HARQ buffer may include the MAC PDU. HARQ may be a combination of high-rate forward error-correcting coding with automatic repeat request (ARQ) error control. The HARQ buffer may maintain the corresponding uplink payload to be transmitted by applying the error-correcting coding. In some embodiments, the wireless communication node may cause the wireless communication device to maintain the HARQ buffer from the transmission of the RA preamble and the corresponding uplink payload that is made on CFRA resource and it is the transmission of the last RA attempt.

In some embodiments, the wireless communication device may identify, calculate, or determine an initial new data indicator (NDI) value for a new NDI of a transmission of the HARQ process occurring prior to the transmission of the RA preamble and the corresponding uplink channel payload to the wireless communication node that is made on CFRA resource and it is the transmission of the last RA attempt. The NDI may be used to define or identify whether the scheduling from the wireless communication node to the wireless communication device is for an initial transmission (e.g., a new transmission) or a retransmission. The wireless communication device may determine whether the scheduling information (e.g., PDCCH addressed to C-RNTI, UL grant in RAR, or UL grant in the fallback RAR) is for new transmission or retransmission based on comparing of the NDI value received in the scheduling information with an initial NDI value. The initial NDI value may be assigned the same HARQ process. Or the wireless communication device may determine whether the scheduling information (e.g., PDCCH addressed to C-RNTI, UL grant in RAR, or UL grant in the fallback RAR) is for new transmission or retransmission by comparing the NDI value received in the scheduling information with the previous NDI value used for the same HARQ process. If the NDI value is determined to be not toggled, then the scheduling received may be to require a retransmission. If the NDI value is determined to be togged, then the scheduling received may be to require a new transmission. The initial NDI value may be <NUM> or <NUM>, and may be determined in accordance with a protocol (e.g., specifying the transmission of the payload via the uplink channel or RRC). In some embodiments, the wireless communication node may cause the wireless communication device to identify, calculate, or determine an initial new data indicator (NDI) value for the new NDI of a transmission of the HARQ process occurring prior to the transmission of the RA preamble and the corresponding uplink channel payload to the wireless communication node that is made on CFRA resource and it is the transmission of the last RA attempt.

In some embodiments, the wireless communication device that is to transmit the RA preamble and the corresponding uplink channel payload to the wireless communication node that is made on CFRA resource and it is the transmission of the last RA attempt may correspond to a new data indicator (NDI) with an initial value. The NDI may be used to define or identify whether the communication from the wireless communication device is an initial transmission. In some embodiments, the NDI may be set according to protocol. In some embodiments, the wireless communication node may receive the RA preamble and the corresponding uplink channel payload from the wireless communication node that is considered with the initial NDI value when the transmission of RA preamble and the corresponding uplink channel payload is made on CFRA resource and it is the transmission of the last RA attempt.

The method <NUM> may include recommunicating the payload (<NUM>). The wireless communication device may determine whether the initial transmission of the uplink channel payload is successful. The wireless communication may refrain from retransmission of the uplink channel upload, responsive to a success of the transmission uplink channel payload for the wireless communication node. Conversely, the wireless communication device may resend or retransmit the corresponding uplink channel upload through an uplink grant to the wireless communication node, responsive to a failure of the transmitted uplink channel payload for the wireless communication node. The uplink grant may correspond to a permission to transmit data via the uplink channel, such as the uplink channel payload. The wireless communication node may in turn re-receive the corresponding uplink channel upload through the uplink grant from the wireless communication device.

In some embodiments, the wireless communication device may resend or retransmit the corresponding uplink channel payload through the uplink grant corresponding to the NDI with the initial NDI value. The wireless communication node may re-receive the corresponding uplink channel payload through the uplink grant corresponding to the NDI with the initial NDI value. In some embodiments, the wireless communication node may transmit a download channel addressed to a cell radio network temporary identifier (C-RNTI) to the wireless communication device. The C-RNTI may include a current NDI value (e.g., <NUM> or <NUM>). In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload through the uplink grant of the downlink channel address to the C-RNTI. In some embodiments, the uplink grant may be from the downlink channel addressed to the cell radio network temporary identifier (C-RNTI). The wireless communication device may in turn receive the download channel address the C-RNTI from the wireless communication node.

In some embodiments, the wireless communication device determine whether the retransmission of the uplink channel payload for the wireless communication node is successful or a failure according to whether the current NDI value differs from the initial NDI value (or previous NDI value) of the same HARQ process scheduled. Responsive to determination that the retransmission is successful, the wireless communication device may refrain from additional retransmissions, and may further perform new transmission if scheduled Otherwise, responsive to determination that the failure of the retransmission, the wireless communication device may retransmit the corresponding uplink channel as scheduled. In some embodiments, the wireless communication device may compare the current NDI value with the initial NDI value (or previous NDI value) of the same HARQ process scheduled. When the current NDI value matches the initial NDI value(or previous NDI value) of the same HARQ process scheduled, the wireless communication device may resend or retransmit the corresponding uplink channel payload that is buffered in a buffer of the HARQ process scheduled (e.g. HARQ process <NUM>). Conversely, when the current NDI value differs from the initial NDI value, the wireless communication device may initiate a transmission based on a new scheduling of HARQ process scheduled (e.g. HARQ process <NUM>).

In some embodiments, responsive to the determination of the failure of the retransmission, the wireless communication device may retransmit the corresponding uplink channel according to whether the NDI has changed in value relative to the initial NDI value (or previous NDI value) of the same HARQ process scheduled. In some embodiments, the wireless communication device may resend or retransmit, responsive to receive the uplink grant address to the C-RNTI and to the RA procedure identified as contention free RA (CFRA) procedure, the corresponding uplink channel. The retransmission of the corresponding uplink channel may be in accordance with whether the NDI has changed in value relative to the initial value (or previous NDI value) of the same HARQ process scheduled. When the NDI is unchanged in value relative to the initial value(or previous NDI value) of the same HARQ process scheduled, the wireless communication device may retransmit the corresponding uplink channel payload that is buffered in a buffer of HARQ process scheduled (e.g. HARQ process <NUM>). Conversely, when the NDI is changed in value relative to the initial value(or previous NDI value) of the same HARQ process scheduled, the wireless communication device may initiate a transmission based on a new scheduling of HARQ process scheduled (e.g. HARQ process <NUM>).

In some embodiments, the wireless communication device may resend or retransmit the corresponding uplink channel payload using the MAC PDU to the wireless communication device. For example, the wireless communication device may generate the MAC PDU to transmit the uplink channel payload to the wireless communication node. In some embodiments, the HARQ buffer may include the MAC PDU used to retransmit. The wireless communication device may resend or retransmit the corresponding uplink channel payload in the MAC PDU maintained in the HARQ buffer. In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device using the MAC PDU. In some embodiments, the wireless communication device may resend or retransmit the corresponding uplink channel payload only once to the wireless communication node. The wireless communication node may re-receive the corresponding uplink channel payload only once from the wireless communication device.

In some embodiments, the wireless communication device may resend or retransmit the corresponding uplink channel payload using a redundant version (RV) to the wireless communication node. The RV may correspond to a redundant copy of the payload to be retransmitted, and may be specified in accordance with a specification. In some embodiments, the wireless communication device may re-receive the corresponding uplink channel payload from the wireless communication device using the RV.

The method <NUM> may include communicating a response (<NUM>). In some embodiments, the wireless communication node may send, provide transmit a fallback RA response (RAR) (e.g., included in MsgB). In some embodiments, the wireless communication device may identify, retrieve, or receive a fallback RA response (RAR). The RAR may define or include the uplink grant to be used to retransmit the corresponding uplink channel payload. The RA procedure may include or is identified as a contention free RA (CFRA) procedure. In some embodiments, the fallback RAR may include RV to be used for retransmission of the corresponding uplink channel payload.

Claim 1:
A method, comprising:
transmitting, by a wireless communication device in a random access, RA, procedure, a RA preamble and a corresponding uplink channel payload to a wireless communication node;
receiving, by the wireless communication device from the wireless communication node, a fallback RA response, RAR, including an uplink grant, wherein the RA procedure comprises a contention free RA, CFRA, procedure;
receiving, by the wireless communication device from the wireless communication node, a downlink channel addressed to a cell radio network temporary identifier, C-RNTI, wherein the C-RNTI includes a current new data indicator, NDI, value;
comparing, by the wireless communication device, the current NDI value with a previous NDI value;
establishing, by the wireless communication device, a medium access control, MAC, protocol data unit, PDU, based on a MsgA buffer, wherein the corresponding uplink channel payload is based on the MsgA buffer; and
retransmitting, by the wireless communication device to the wireless communication node, the corresponding uplink channel payload using the MAC PDU through the uplink grant according to whether the current NDI value is different from the previous NDI value.