Patent Description:
3GPP document R2-<NUM> discusses RRC issues, and 3GPP document R1-<NUM> discusses procedure for two-step RACH.

A method and device are disclosed from the perspective of a User Equipment (UE) and are defined in the independent claims. The dependent claims define preferred embodiments thereof.

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband), WiMax, 3GPP NR (New Radio), or some other modulation techniques.

In particular, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named "3rd Generation Partnership Project" referred to herein as 3GPP, including: <NUM> V15. <NUM>, "E-UTRA and E-UTRAN; Overall description; Stage <NUM>"; RP-<NUM>, "Work Item on NR small data transmissions in INACTIVE state", ZTE Corporation; TS <NUM> V15. <NUM>, "E-UTRA, Radio Resource Control (RRC) protocol specification"; TS <NUM> V15. <NUM>, "NR, Radio Resource Control (RRC) protocol specification"; RP-<NUM>, "New SID on support of reduced capability NR devices", Ericsson; TS <NUM> V15. <NUM>, "E-UTRA; Medium Access Control (MAC) protocol specification"; R2-<NUM>, "Introduction of <NUM>-step RACH in <NUM>", ZTE Corporation and Sanechips; and R2-<NUM>, "Introduction of <NUM>-step RA", Ericsson.

<FIG> shows a multiple access wireless communication system according to one embodiment of the invention. An access network <NUM> (AN) includes multiple antenna groups, one including <NUM> and <NUM>, another including <NUM> and <NUM>, and an additional including <NUM> and <NUM>. In <FIG>, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal <NUM> (AT) is in communication with antennas <NUM> and <NUM>, where antennas <NUM> and <NUM> transmit information to access terminal <NUM> over forward link <NUM> and receive information from access terminal <NUM> over reverse link <NUM>. Access terminal (AT) <NUM> is in communication with antennas <NUM> and <NUM>, where antennas <NUM> and <NUM> transmit information to access terminal (AT) <NUM> over forward link <NUM> and receive information from access terminal (AT) <NUM> over reverse link <NUM>. In a FDD system, communication links <NUM>, <NUM>, <NUM> and <NUM> may use different frequency for communication. For example, forward link <NUM> may use a different frequency then that used by reverse link <NUM>.

In communication over forward links <NUM> and <NUM>, the transmitting antennas of access network <NUM> may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals <NUM> and <NUM>. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to all its access terminals.

An access network (AN) may be a fixed station or base station used for communicating with the terminals and may also be referred to as an access point, a Node B, a base station, an enhanced base station, an evolved Node B (eNB), a network node, a network, or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

<FIG> is a simplified block diagram of an embodiment of a transmitter system <NUM> (also known as the access network) and a receiver system <NUM> (also known as access terminal (AT) or user equipment (UE)) in a MIMO system <NUM>. At the transmitter system <NUM>, traffic data for a number of data streams is provided from a data source <NUM> to a transmit (TX) data processor <NUM>.

Preferably, each data stream is transmitted over a respective transmit antenna. TX data processor <NUM> formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor <NUM>.

At receiver system <NUM>, the transmitted modulated signals are received by NR antennas 252a through 252r and the received signal from each antenna <NUM> is provided to a respective receiver (RCVR) 254a through 254r. Each receiver <NUM> conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding "received" symbol stream.

Turning to <FIG>, this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the invention. As shown in <FIG>, the communication device <NUM> in a wireless communication system can be utilized for realizing the UEs (or ATs) <NUM> and <NUM> in <FIG> or the base station (or AN) <NUM> in <FIG>, and the wireless communications system is preferably the NR system. The communication device <NUM> may include an input device <NUM>, an output device <NUM>, a control circuit <NUM>, a central processing unit (CPU) <NUM>, a memory <NUM>, a program code <NUM>, and a transceiver <NUM>. The control circuit <NUM> executes the program code <NUM> in the memory <NUM> through the CPU <NUM>, thereby controlling an operation of the communications device <NUM>. The communications device <NUM> can receive signals input by a user through the input device <NUM>, such as a keyboard or keypad, and can output images and sounds through the output device <NUM>, such as a monitor or speakers. The transceiver <NUM> is used to receive and transmit wireless signals, delivering received signals to the control circuit <NUM>, and outputting signals generated by the control circuit <NUM> wirelessly. The communication device <NUM> in a wireless communication system can also be utilized for realizing the AN <NUM> in <FIG>.

<FIG> is a simplified block diagram of the program code <NUM> shown in <FIG> in accordance with one embodiment of the invention. In this embodiment, the program code <NUM> includes an application layer <NUM>, a Layer <NUM> portion <NUM>, and a Layer <NUM> portion <NUM>, and is coupled to a Layer <NUM> portion <NUM>. The Layer <NUM> portion <NUM> generally performs radio resource control. The Layer <NUM> portion <NUM> generally performs link control. The Layer <NUM> portion <NUM> generally performs physical connections.

The general description of early data transmission (EDT) in RRC_IDLE state is specified in 3GPP TS <NUM> as follows:.

EDT allows one uplink data transmission optionally followed by one downlink data transmission during the random access procedure.

EDT is triggered when the upper layers have requested the establishment or resumption of the RRC Connection for Mobile Originated data (i.e., not signalling or SMS) and the uplink data size is less than or equal to a TB size indicated in the system information. EDT is not used for data over the control plane when using the User Plane CloT EPS optimizations.

EDT is only applicable to BL UEs, UEs in Enhanced Coverage and NB-loT UEs.

The work item of small data transmission in NR has been approved in RAN plenary #<NUM> meeting. The description of the work item is specified in 3GPP RP-<NUM> as follows:.

NR supports RRC_INACTIVE state and UEs with infrequent (periodic and/or non-periodic) data transmission are generally maintained by the network in the RRC_INACTIVE state. Until Rel-<NUM>, the RRC_INACTIVE state doesn't support data transmission. Hence, the UE has to resume the connection (i.e. move to RRC_CONNECTED state) for any DL (MT) and UL (MO) data. Connection setup and subsequently release to INACTIVE state happens for each data transmission however small and infrequent the data packets are. This results in unnecessary power consumption and signalling overhead.

Specific examples of small and infrequent data traffic include the following use cases:.

As noted in 3GPP TS <NUM>, the NR system shall:.

Signalling overhead from INACTIVE state UEs for small data packets is a general problem and will become a critical issue with more UEs in NR not only for network performance and efficiency but also for the UE battery performance. In general, any device that has intermittent small data packets in INACTIVE state will benefit from enabling small data transmission in INACTIVE.

The key enablers for small data transmission in NR, namely the INACTIVE state, <NUM>-step, <NUM>-step RACH and configured grant type-<NUM> have already been specified as part of Rel-<NUM> and Rel-<NUM>. So, this work builds on these building blocks to enable small data transmission in INACTIVE state for NR.

This work item enables small data transmission in RRC_INACTIVE state as follows:.

No new RRC state should be introduced in this WID. Transmission of small data in UL, subsequent transmission of small data in UL and DL and the state transition decisions should be under network control.

In LTE, the RACH Occasion's (RO) configurations for Random Access (RA) with and without EDT could be provided by Radio Resource Control (RRC), as specified in 3GPP TS <NUM> as below:.

The IE PRACH-ConfigSIB and IE PRACH-Config are used to specify the PRACH configuration in the system information and in the mobility control information, respectively. <IMG>
<IMG>
<IMG>.

In NR, the RO's configurations for <NUM>-step and <NUM>-step RA and parameter configurations to indicate the RA preamble could be provided by RRC, as specified in 3GPP TS <NUM> as follows:.

The IE RACH-ConfigCommon is used to specify the cell specific random-access parameters. <IMG>
<IMG>
<IMG>.

The IE RACH-ConfigCommonTwoStepRA is used to specify cell specific <NUM>-step random-access type parameters. <IMG>
<IMG>.

The IE RACH-ConfigGeneric is used to specify the random-access parameters both for regular random access as well as for beam failure recovery. <IMG>
<IMG>.

The IE RACH-ConfigGenericTwoStepRA is used to specify the <NUM>-step random access type parameters.

In LTE, the RA preamble selection for EDT is specified in 3GPP TS <NUM> as follows:.

The following information for related Serving Cell is assumed to be available before the procedure can be initiated for NB-loT UEs, BL UEs or UEs in enhanced coverage, as specified in TS <NUM> [<NUM>]:.

In addition, the parameter configurations to indicate the RA preamble could be provided by RRC, as specified in 3GPP TS <NUM> as follows:.

The IE RACH-ConfigCommon is used to specify the generic random access parameters. <IMG>
<IMG>.

In NR, the parameters to indicate the <NUM>-step and <NUM>-step RA preamble are specified in th CR of 3GPP TS <NUM> (3GPP R2-<NUM>) as follows:.

RRC configures the following parameters for the Random Access procedure:
[.

When the Random Access procedure is initiated on a Serving Cell, the MAC entity shall:
[.

In LTE, a UE can transmit user data in RRC_IDLE state via a random access (RA) procedure for early data transmission (EDT). The early data transmission can be triggered when the upper layers have requested the establishment or resumption of the RRC connection, as discussed in 3GPP TS <NUM>.

In NR, small data transmission in RRC_INACTIVE state is to be studied to reduce power consumption and signalling overhead without establishing a RRC connection and subsequently release, as discussed in 3GPP RP-<NUM>. To enable small data transmission in RRC_INACTIVE state, RACH-based method and/or pre-configured PUSCH resources based method are currently considered. The RACH-based method may include <NUM>-step and/or <NUM>-step RA. When some Uplink (UL) data (e.g. small data) is available for transmission while the UE is in RRC INACTIVE state, the UE may initiate a RRC Resume procedure in RRC_INACTIVE state which triggers a RA procedure for the small data transmission.

For <NUM>-step RA (e.g. with small data), the UE may select RA resources and then send a RA preamble (Msg1). The RA resources may include RA preamble, SS/PBCH block (SSB), Channel State Information Reference Signal (CSI-RS) and/or Random Access Channel (RACH) occasion. The NW may receive the Msg1 and send a RAR (Msg2). In response to receiving the Msg2, the UE may use the UL grant in the Msg2 to transmit a Msg3 which may contain RRC resume request and the small data. In response to receiving the Msg3, the NW may send a Msg4 to inform the UE to complete the RA procedure and transmit a RRC release message to keep the UE in the RRC_INACTIVE state.

For <NUM>-step RA (e.g. with small data), the UE may select RA resources and then send a MSGA including a RA preamble and a Physical Uplink Shared Channel (PUSCH) payload. The RA resources may include RA preamble, SSB, CSI-RS, RACH occasion(s), and/or PUSCH occasion(s). The PUSCH payload may contain RRC resume request and the small data. In response to receiving the MSGA, the NW may send a MSGB to inform the UE to complete the RA procedure and may transmit a RRC release message to keep the UE in the RRC _INACTIVE state. If the NW receives a RA preamble but fails to receive a PUSCH payload, the NW may send a MSGB to inform the UE to fall back to Msg3. The UE may use the UL grant in the MSGB to transmit a Msg3. The Msg3 may contain RRC resume request and the small data. In response to receiving the Msg3, the NW may send a Msg4 to inform the UE to complete the RA procedure and may transmit a RRC release message to keep the UE in the RRC_INACTIVE state.

During a RA procedure in LTE, the configuration to indicate RACH occasion(s) (RO(s)) is provided by RRC on each coverage enhancement level, as specified in 3GPP TS <NUM>. There is a first IE (e.g. PRACH-Config) to specify the PRACH configuration. In the first IE, there is a list of first parameters (e.g. PRACH-ParametersCE) for RA without EDT and a list of second parameters (e.g. edt-PRACH-ParametersCE) for RA with EDT (as shown in <FIG>, which shows an example of RO configuration(s) in LTE). The parameters under the first parameter (e.g. prach-ConfigIndex, prach-FreqOffset, prach-StartingSubframe) and the second parameter (e.g. prach-ConfigIndex, prach-FreqOffset, prach-StartingSubframe) indicate the RO(s), including configuration index and/or frequency offset of PRACH. If the RO(s) for RA with EDT (i.e. the RO(s) indicated by the second parameter) are not configured, the RA with EDT uses the RO(s) for RA without EDT (i.e. the RO(s) indicated by the first parameter). The RA with EDT is considered to share the RO(s) with the RA without EDT.

During a RA procedure in NR, the configuration to indicate RO(s) is provided by RRC on each Bandwidth Part (BWP), as discussed in 3GPP TS <NUM>. There is a second IE (e.g. RACH-ConfigCommon) for <NUM>-step RA configuration and a third IE (e.g. RACH-ConfigCommonTwoStepRA) for <NUM>-step RA configuration. There is a fourth IE (e.g. RACH-ConfigGeneric) in the second IE and a fifth IE (e.g. RACH-ConfigGenericTwoStepRA) in the third IE to specify the RA parameters including RO(s) configuration (as shown in <FIG>, which shows an example of RO configuration(s) in NR). There is a first group of parameters (e.g. prach-ConfigurationIndex, msg1-FDM, msg1-FrequencyStart) in the fourth IE and a second group of parameters (e.g. msgA-PRACH-ConfigurationIndex, msgA-RO-FDM, msgA-RO-FrequencyStart) in the fifth IE to indicate the RO(s), including configuration index and/or frequency offset of PRACH. If the RO(s) for <NUM>-step RA (i.e. the RO(s) indicated by the fifth IE) are not configured, the <NUM>-step RA uses the RO(s) for <NUM>-step RA (i.e. the RO(s) indicated by the fourth IE). The <NUM>-step RA is considered to share the RO(s) with <NUM>-step RA.

To enable RACH-based small data transmission in NR, RO configurations for normal RA (e.g. not used for small data transmission) and SDT RA (e.g. used for small data transmission) may be needed. If both <NUM>-step RA and <NUM>-step RA are supported, RO configurations for <NUM>-step RA and <NUM>-step RA may be needed.

For EDT in LTE, if the RO(s) for RA with early data are not configured, the RA with early data may use the RO(s) for RA without early data. In NR, if the RO(s) for <NUM>-step RA with small data are not configured, the <NUM>-step RA with small data may use the RO(s) for <NUM>-step RA without small data. The <NUM>-step RA with small data is considered to share the RO(s) with the <NUM>-step RA without small data. If the RO(s) for <NUM>-step RA with small data are not configured, the <NUM>-step RA with small data may use the RO(s) for <NUM>-step RA without small data. The <NUM>-step RA with small data is considered to share the RO(s) with the <NUM>-step RA without small data.

For example, during the RA procedure for small data transmission in NR, two groups of parameters may be needed to indicate the RO(s) (as showed in <FIG>, which shows an example of RO configuration case <NUM> (NR with Small Data Transmission (SDT)). In the second IE (e.g. RACH ConfigCommon), there may be a sixth IE containing a third group of parameters for <NUM>-step RA with small data. In the third IE (e.g. RACH-ConfigCommonTwoStepRA), there may be a seventh IE containing a fourth group of parameters for <NUM>-step RA with small data. If the RO(s) for <NUM>-step RA with small data (i.e. the RO(s) indicated by the sixth IE) are not configured, the <NUM>-step RA with small data may use the RO(s) for <NUM>-step RA without small data (i.e. the RO(s) indicated by the fourth IE). If the RO(s) for <NUM>-step RA with small data (i.e. the RO(s) indicated by the seventh IE) are not configured, the <NUM>-step RA with small data may use the RO(s) for <NUM>-step RA without small data (i.e. the RO(s) indicated by the fifth IE).

Considering small data transmission in NR, various RA types may coexist, and the possible RA types may include normal <NUM>-step (or may be called <NUM>-step non-SDT), normal <NUM>-step (or may be called <NUM>-step non-SDT), <NUM>-step SDT, and <NUM>-step SDT. However, based on the configuration of indicating supported RA types and RO(s) of the supported RA types (as shown in in <FIG>, which shows an example of RO configuration case <NUM> (NR with SDT)) there exists some ambiguity for some cases on whether a RA type shares RO(s) with another RA type. The ambiguity may cause different understanding between UE and NW, which resulting in inaccurate or inefficient resource usage.

It is possible that <NUM>-step normal RA (may be always) has its own RO(s), and other RA types could have its own RO(s) or shares RO(s) with other RA type based on the configuration. Among the (eight) cases that can be indicated based on the configuration as shown in <FIG>, there may be three ambiguous cases in indicating the shared RO(s). The configuration examples are discussed below.

The RO(s) in the fourth IE (e.g. RACH-ConfigGeneric) may be configured. The RO(s) in the sixth IE may be configured. The RO(s) in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) may not be configured. The RO(s) in the seventh IE may not be configured. The configuration may cause the following ambiguity (e.g. same configuration may cause different interpretations).

As an example, in a first interpretation, normal <NUM>-step may use the RO(s) of normal <NUM>-step and the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. The normal <NUM>-step may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric). The <NUM>-step SDT may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric).

As an example, in a second interpretation, normal <NUM>-step may use the RO(s) of normal <NUM>-step and the <NUM>-step SDT may use the RO(s) of <NUM>-step SDT. The normal <NUM>-step may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric). The <NUM>-step SDT may use the RO(s) in the sixth IE. However, following the logic mentioned above, if the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step, indicated by the fifth IE (e.g. RACH-ConfigGenericTwoStepRA).

As an example, in a third interpretation, normal <NUM>-step may use the RO(s) of <NUM>-step SDT and the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. The normal <NUM>-step may use the RO(s) in the sixth IE. The <NUM>-step SDT may use the RO(s) in the sixth IE. However, following the logic mentioned above, if the RO(s) indicated by the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) are not configured, the normal <NUM>-step may use the RO(s) of normal <NUM>-step, indicated by the fourth IE (e.g. RACH-ConfigGeneric).

To solve the ambiguity, one alternative could be to define (or hard-code) one specific interpretation (e.g. of the above interpretations) in case the network provides (or the UE receives) a configuration such that the RA type of normal <NUM>-step RA and the RA type of <NUM>-step SDT do not have their own RO(s) (while the RA type of normal <NUM>-step and the RA type of <NUM>-step SDT may have their own RO). For example, if the UE receives such configuration, the UE could determine the RO(s) of a specific RA type according to the first (or second, or third) interpretation.

The RO(s) in the fourth IE (e.g. RACH-ConfigGeneric) may be configured. The RO(s) in the sixth IE may be configured. The RO(s) in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) may be configured. The RO(s) in the seventh IE may not be configured. The configuration may cause the following ambiguity (e.g. same configuration may cause different interpretations).

As an example, in a first interpretation, <NUM>-step SDT may use the RO(s) of normal <NUM>-step. The <NUM>-step SDT may use the RO(s) in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA). The RO(s) in the seventh IE may not be configured.

As an example, in a second interpretation, <NUM>-step SDT may use the RO(s) of <NUM>-step SDT. The <NUM>-step SDT may use the RO(s) in the sixth IE. However, following the logic mentioned above, if the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step, indicated by the fifth IE (e.g. RACH-ConfigGenericTwoStepRA).

To solve the ambiguity, one alternative could be to define (or hard-code) one specific interpretation (e.g. of the above interpretations) in case the network provides (or the UE receives) a configuration such that the RA type of <NUM>-step SDT do not have its own RO(s) (while the RA type of normal <NUM>-step, the RA type of normal <NUM>-step, and the RA type of <NUM>-step SDT may have their own RO(s)). For example, if the UE receives such configuration, the UE determines the RO(s) of a specific RA type according to the first (or second) interpretation.

The RO(s) in the fourth IE (e.g. RACH-ConfigGeneric) may be configured. The RO(s) in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) may be configured. The RO(s) in the sixth IE may not be configured. The RO(s) in the seventh IE may not be configured. The configuration may cause the following ambiguity (e.g. same configuration may cause different interpretations):.

As an example, in a first interpretation, <NUM>-step SDT may use the RO(s) of normal <NUM>-step and the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. The <NUM>-step SDT may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric). The <NUM>-step SDT may use the RO(s) in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA).

As an example, in a second interpretation, <NUM>-step SDT may use the RO(s) of normal <NUM>-step and the <NUM>-step SDT may use the RO(s) of <NUM>-step SDT. The <NUM>-step SDT may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric). The <NUM>-step SDT may use the RO(s) in the fourth IE (e.g. RACH-ConfigGeneric). However, following the logic mentioned above, if the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step, indicated by the fifth IE (e.g. RACH-ConfigGenericTwoStepRA).

To solve the ambiguity, one alternative could be to define (or hard-code) one specific interpretation (e.g. of the above interpretations) in case the network provides (or the UE receives) a configuration such that the RA type of <NUM>-step SDT and the RA type of <NUM>-step SDT do not have their own RO(s) (while the RA type of normal <NUM>-step and the RA type of normal <NUM>-step may have their own RO). For example, if the UE receives such configuration, the UE determines the RO(s) of a specific RA type according to the first (or second) interpretation.

Based on the RA configurations provided by the NW on a BWP, the UE should unambiguously identify the RO(s) to be used for a corresponding RA type.

Throughout the present disclosure, the RO(s) of a RA type may be one RO and/or a set of ROs. Throughout the present disclosure, the RO configuration(s) of a RA type may include one RO and/or a set of ROs.

To solve the issue, NW provides a parameter (or indication) to indicate that for a first RA type (e.g. <NUM>-step SDT), the RO(s) of which RA type (e.g. a second RA type or a third RA type) are shared with the first RA type (e.g. <NUM>-step SDT). In a first claimed option the parameter (or indication) is explicit configuration. The parameter (or indication) may be included in a RO configuration. The parameter (or indication) may indicate which RO(s) (e.g. the RO(s) of which RA type) is used by the first RA type in case the first RA type does not have its own RO configuration(s). The parameter (or indication) may be present if the first RA type does not have its own RO configuration(s). The parameter (or indication) may be absent if the first RA type has its own RO configuration(s).

The shared RO(s) may be related the second RA type and/or the third RA type. The second or third RA type may be different from the first RA type. The first RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second or third RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second RA type and the third RA type may be different. The parameter (or indication) may be configured in the configurations of the first RA type, the second RA type and/or the third RA type. The parameter (or indication) may be a Boolean, an enumerated, and/or an integer. The parameter (or indication) may be provided to a UE (e.g. transmitted from NW to UE). The parameter (or indication) may be provided in a RRC message (e.g. a common signaling, a dedicated signaling, system information, dedicated RRC message, RRC reconfiguration message, or a handover command).

In one example, there may be a sixth IE for <NUM>-step SDT configured in the second IE (e.g. RACH-ConfigCommon) and a seventh IE for <NUM>-step SDT configured in the third IE (e.g. RACH-ConfigCommonTwoStepRA). There may be a parameter configured in the seventh IE to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the seventh IE are not configured. There may be a parameter configured in the third IE (e.g. RACH-ConfigCommonTwoStepRA) to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the seventh IE are not configured. There may be a parameter configured in the fourth, fifth, and/or sixth IE to indicate whether the RO(s) in this IE are used by the <NUM>-step SDT when the RO(s) indicated in the seventh IE are not configured.

In one example, there may be a third group of parameters for <NUM>-step SDT configured in the fourth IE (e.g. RACH-ConfigGeneric) and a fourth group of parameters for <NUM>-step SDT configured in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA). The third group of parameters may align with the first group of parameters for normal <NUM>-step RA. The fourth group of parameters may align with the second group of parameters for normal <NUM>-step RA. There may be a parameter configured in the fourth group of parameters to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the fourth group of parameters are not configured. There may be a parameter configured in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the fourth group of parameters are not configured. There may be a parameter configured in the third IE (e.g. RACH-ConfigCommonTwoStepRA) to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the fourth group of parameters are not configured. There may be a parameter configure in the first, second, and/or third group of parameters to indicate whether the RO(s) indicated by this group of parameters are used by the <NUM>-step SDT when the RO(s) indicated in the fourth group of parameters are not configured.

In one example, there may be an eighth IE to specify the SDT configurations. There may be a sixth IE for <NUM>-step SDT and a seventh IE for <NUM>-step SDT in the eighth IE. There may be a parameter configured in the seventh IE to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the seventh IE are not configured. There may be a parameter configured in the eighth IE to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the seventh IE are not configured. There may be a parameter configured in the fourth, fifth, and/or sixth IE to indicate whether the RO(s) in this IE are used by the <NUM>-step SDT when the RO(s) indicated in the seventh IE are not configured.

In one example, there may be an eighth IE to specify the SDT configurations. There may be a third group of parameters for <NUM>-step SDT and a fourth group of parameters for <NUM>-step SDT in the eighth IE. There may be a parameter configured in the fourth group of parameters to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the fourth group of parameters are not configured. There may be a parameter configured in the eighth IE to indicate which RO(s) the <NUM>-step SDT may use when the RO(s) indicated in the fourth group of parameters are not configured. There may be a parameter configured in the first group of parameters, second group of parameters, and/or third group of parameters to indicate whether the RO(s) indicated by this group of parameters are used by the <NUM>-step SDT when the RO(s) indicated in the fourth group of parameters are not configured.

To solve the issue, the parameter (or indication) described above may be provided (or indicated) implicitly. The parameter (or indication) may be an implicit configuration.

As an example, the NW may indicate the RO(s) of which RA type (e.g. a second RA type or a third RA type) are shared with a first RA type (e.g. <NUM>-step SDT) by the presence or absence of one or more specific parameters/configurations/information elements.

As an example, the NW may indicate the RO(s) of which RA type (e.g. a second RA type or a third RA type) are shared with a first RA type (e.g. <NUM>-step SDT) by which parameter, configuration, or information element includes the corresponding configuration associated with the first RA type.

As an example, the NW could indicate the RO(s) of which RA type (e.g. a second RA type or a third RA type) are shared with a first RA type (e.g. <NUM>-step SDT) by configuring the RO configuration(s) of the first RA type (e.g. <NUM>-step SDT) in different IEs or in (or at) different parameters in a IE. The first RA type without its own RO configuration(s) may use the shared RO(s) depends on the configurations. The RO configuration(s) of a RA type may be included in an IE and/or a group of parameters. The shared RO(s) may related to a second and/or a third RA type. The second or third RA type may be different from the first RA type. The second or third RA type may be normal <NUM>-step, <NUM>-step SDT, normal <NUM>-step, and/or <NUM>-step SDT.

In one example (<NUM>-step SDT is the first RA type as an example), there may be a fourth group and a fifth group of parameters to indicate the RO(s) for <NUM>-step SDT. The fifth group of parameters may be a duplication of the fourth group of parameters. One of the two groups of parameters may be present, and the other group of parameters may be absent. The <NUM>-step SDT may use the shared RO(s) if one of the groups of parameters is present, but the RO(s) indicated by this group of parameters are not configured. The <NUM>-step SDT may use the shared RO(s) depend on which group of parameters is present.

There may be a first group of parameters in the fourth IE (e.g. RACH-ConfigGeneric) to indicate the RO(s) for normal <NUM>-step RA. There may be a second group of parameters in the fifth IE (e.g. RACH-ConfigGenericTwoStepRA) to indicate the RO(s) for normal <NUM>-step RA.

Example 1a: There may be a third group of parameters in the fourth IE to indicate the RO(s) for <NUM>-step SDT. There may be a fourth and fifth group of parameters in the fifth IE to indicate the RO(s) for <NUM>-step SDT.

Example 1b: There may be an eighth IE to specify the SDT configurations. There may be a third group of parameters in the eighth IE to indicate the RO(s) for <NUM>-step SDT. There may be a fourth and fifth group of parameters in the eighth IE to indicate the RO(s) for <NUM>-step SDT.

If the fourth group of parameters is present but the RO(s) indicated by the forth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the second group of parameters. The <NUM>-step SDT may be considered to share the RO(s) with the normal <NUM>-step RA. If the fifth group of parameters is present but the RO(s) indicated by the fifth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the third group of parameters. The <NUM>-step SDT may be considered to share the RO(s) with the <NUM>-step SDT.

In one example (<NUM>-step SDT is the first RA type as an example), the RO(s) for <NUM>-step SDT may be configured in different IEs. The <NUM>-step SDT may use the shared RO(s) if the configurations for <NUM>-step SDT is present in one IE, but the RO(s) indicated by this configuration are not configured. The <NUM>-step SDT may use the shared RO(s) depend on the configurations for <NUM>-step SDT is present in which IE.

There may be a fourth IE (e.g. RACH-ConfigGeneric) in the second IE (e.g. RACH ConfigCommon) to indicate the RO(s) for normal <NUM>-step RA. There may be a fifth IE (e.g. RACH-ConfigGenericTwoStepRA) in the third IE (e.g. RACH-ConfigCommonTwoStepRA) to indicate the RO(s) for normal <NUM>-step RA.

Example 2a (shown as <FIG>): There may be a sixth IE in the second IE to indicate the RO(s) for <NUM>-step SDT. There may be a seventh IE configured in the second or third IE to indicate the RO(s) for <NUM>-step SDT. If the seventh IE is present in the third IE but the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) indicated by the fifth IE. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA. If the seventh IE is present in the second IE but the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) indicated by the sixth IE. The <NUM>-step SDT is considered to share the RO(s) with the <NUM>-step SDT.

Example 2b (shown as <FIG>): There may be a sixth IE in the second IE for <NUM>-step SDT. There may be a seventh IE configured in the third IE for <NUM>-step SDT. There may be a third group of parameters in the sixth IE to indicate the ROs for <NUM>-step SDT. There may be a fourth group of parameters in the sixth or seventh IE to indicate the RO(s) for <NUM>-step SDT. If the fourth group of parameters is present in the seventh IE but the RO(s) indicated by the fourth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the second group of parameters. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA. If the fourth group of parameters is present in the sixth IE but the RO(s) indicated by the fourth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the third group of parameters. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA.

Example 2c: There may be a third group of parameters in the fourth IE to indicate the RO(s) for <NUM>-step SDT. There may be a fourth group of parameters in the fourth or fifth IE to indicate the RO(s) for <NUM>-step SDT. If the fourth group of parameters is present in the fifth IE but the RO(s) indicated by the fourth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the second group of parameters. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA. If the fourth group of parameters is present in the fourth IE but the RO(s) indicated by the fourth group of parameters are not configured, the <NUM>-step SDT may use the RO(s) indicated by the third group of parameters. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA.

In one example (<NUM>-step SDT is the first RA type as an example), the RO(s) for <NUM>-step SDT may be configured at different parameters in the same IE. The <NUM>-step SDT may use the shared RO(s) if the configurations for <NUM>-step SDT is present, but the RO(s) indicated by this configuration are not configured. The <NUM>-step SDT may use the shared RO(s) depend on the configurations for <NUM>-step SDT is present at which parameter.

There may be a fourth IE (e.g. RACH-ConfigGeneric) configured at a first parameter (e.g. rach-ConfigGeneric) in the second IE (e.g. RACH-ConfigCommon) to indicate the RO(s) for normal <NUM>-step RA. There may be a fifth IE (e.g. RACH-ConfigGenericTwoStepRA) configured at a second parameter (e.g. rach-ConfigGenericTwoStepRA) in the third IE (e.g. RACH-ConfigCommonTwoStepRA) to indicate the RO(s) for normal <NUM>-step RA.

Example 3a (as shown in <FIG>); There may be a sixth IE configured at a third parameter in the second IE to indicate the RO(s) for <NUM>-step SDT. There may be a seventh IE configured at a fourth or fifth parameter in the third IE to indicate the RO(s) for <NUM>-step SDT.

Example 3b (as shown in <FIG>); There may be an eighth IE to specify the SDT configurations. There may be a sixth IE configured at a third parameter in the eighth IE to indicate the RO(s) for <NUM>-step SDT. There may be a seventh IE configured at a fourth or a fifth parameter in the eighth IE to indicate the RO(s) for <NUM>-step SDT.

If the seventh IE is present at the fourth parameter (and is absent at the fifth parameter) but the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) indicated by the fifth IE. The <NUM>-step SDT is considered to share the RO(s) with the normal <NUM>-step RA. If the seventh IE is present at the fifth parameter (and is absent at the fourth parameter) but the RO(s) indicated by the seventh IE are not configured, the <NUM>-step SDT may use the RO(s) indicated by the sixth IE. The <NUM>-step SDT is considered to share the RO(s) with the <NUM>-step SDT.

To solve the issue, it may not be allowed (for the network) to provide a configuration (or any configuration) such that a first RA type (e.g. <NUM>-step SDT) shares the RO(s) with a second RA type if the RO(s) of the first RA type are not configured. Alternatively or additionally, it may be allowed (for the network) to provide a configuration (or any configuration) such that the first RA type (e.g. <NUM>-step SDT) shares the RO(s) with a third RA type if the RO(s) of the first RA type are not configured.

Alternatively or additionally, network may not (or shall not) provide a configuration (or any configuration) such that a first RA type (e.g. <NUM>-step SDT) shares the RO(s) with a second RA type if the RO(s) of the first RA type are not configured. Alternatively or additionally, network may be prohibited to provide (or prevented from providing) a configuration (or any configuration) such that a first RA type (e.g. <NUM>-step SDT) shares the RO(s) with a second RA type if the RO(s) of the first RA type are not configured. Alternatively or additionally, network may provide a configuration (or any configuration) with a restriction (or a limitation) such that a first RA type (e.g. <NUM>-step SDT) does not (or shall not or is unable to) share the RO(s) with a second RA type if the RO(s) of the first RA type are not configured.

The configuration (or any configuration) may refer to the configuration (or any configuration) used to indicate RO(s) of the first RA type. The first RA type may be able to directly share the RO(s) with one RA types (e.g. the second/third RA type). The first RA type may be unable to directly share the RO(s) with more than one RA type (e.g. the second/third RA type). The shared RO(s) may be related to the second/third RA type (other than the first RA type). The first RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The third RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second RA type and the third RA type may be different.

In one example, the NW may configure <NUM>-step SDT to share the RO(s) of normal <NUM>-step, <NUM>-step SDT to share the RO(s) of normal <NUM>-step, and normal <NUM>-step to share the RO(s) of normal <NUM>-step. If the RO(s) of <NUM>-step SDT are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. If the RO(s) of <NUM>-step SDT are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. If the RO(s) of normal <NUM>-step are not configured, the normal <NUM>-step may use the RO(s) of normal <NUM>-step. The <NUM>-step SDT may not use the RO(s) of <NUM>-step SDT if the RO(s) of <NUM>-step SDT are not configured, unless the RO(s) of <NUM>-step SDT and normal <NUM>-step are not configured (i.e. <NUM>-step SDT uses the RO(s) of normal <NUM>-step, normal <NUM>-step uses the RO(s) of normal <NUM>-step, and <NUM>-step SDT uses the RO(s) of normal <NUM>-step). The <NUM>-step SDT may not use the RO(s) of normal <NUM>-step if the RO(s) of <NUM>-step SDT are not configured, unless the RO(s) of normal <NUM>-step are not configured (i.e. <NUM>-step SDT uses the RO(s) of normal <NUM>-step, and normal <NUM>-step uses the RO(s) of normal <NUM>-step).

In one example, the NW may configure <NUM>-step SDT to share the RO(s) of <NUM>-step SDT, <NUM>-step SDT to share the RO(s) of normal <NUM>-step, and normal <NUM>-step to share the RO(s) of normal <NUM>-step. If the RO(s) of <NUM>-step SDT are not configured, the <NUM>-step SDT may use the RO(s) of <NUM>-step SDT. If the RO(s) of <NUM>-step SDT are not configured, the <NUM>-step SDT may use the RO(s) of normal <NUM>-step. If the RO(s) of normal <NUM>-step are not configured, the normal <NUM>-step may use the RO(s) of normal <NUM>-step. The <NUM>-step SDT may not use the RO(s) of normal <NUM>-step if the RO(s) of <NUM>-step SDT are not configured, unless the RO(s) of <NUM>-step SDT and normal <NUM>-step are not configured (i.e. <NUM>-step SDT uses the RO(s) of <NUM>-step SDT, <NUM>-step SDT uses the RO(s) of normal <NUM>-step, and normal <NUM>-step uses the RO(s) of normal <NUM>-step). The <NUM>-step SDT may not use the RO(s) of normal <NUM>-step if the RO(s) of <NUM>-step SDT are not configured, unless the RO(s) of <NUM>-step SDT are not configured (i.e. <NUM>-step SDT uses the RO(s) of <NUM>-step SDT, and <NUM>-step SDT uses the RO(s) of normal <NUM>-step).

The above method(s) to identify (or interpret) the RO(s) for a specific RA type (e.g. the first RA type) could be applied by a UE and/or a network node. Since the UE and the NW should have common understanding on the RO(s) corresponding to different RA configurations, the UE and the NW should apply the same method to identify (or interpret) the RO(s) based on the RA configuration(s) provided by the NW (on a BWP). The UE may determine the RO(s) of a specific RA type based on the configuration provided by NW.

The UE may initiate a <NUM>-step RA to transmit small data when (or in response to) the upper layer indicates a small data transmission and the radio condition is below a threshold (e.g. rsrp-Threshold-msgA). The UE may initiate a <NUM>-step RA to transmit small data when (or in response to) the upper layer indicates a small data transmission and radio condition is above a threshold (e.g. rsrp-Threshold-msgA).

The first RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second or third RA type may be at least one of normal <NUM>-step (i.e. without small data), <NUM>-step SDT, normal <NUM>-step (i.e. without small data), and/or <NUM>-step SDT. The second RA type or the third RA type may be different from the first RA type. The second RA type and the third RA type may be different.

The different types of RA may share the same RO(s) when the NW does not configure another PRACH resources. The different types of RA may share the same RO(s) when the PRACH resources are not enough. The different types of RA may share the same RO(s) when the NW supposes another PRACH resources to be unnecessary.

The UE may receive some configurations related to RA resources for small data transmission provided by the NW. For example, the RA configurations may include some parameters to indicate the RO(s). For example, the RA configurations may include some parameters and/or occasions to indicate whether the different types of RA share the same RO(s). For example, the RA configurations may include the configuration about the shared RO(s). The RA configurations may be provided in system information, RRC signaling, and/or MAC CE.

The UE may be referred to the UE, or a Medium Access Control (MAC) entity of the UE. The UE may be a NR device. The UE may be a NR-light device, as discussed in 3GPP RP-<NUM>. The UE may be a reduced capability device, as discussed in 3GPP RP-<NUM>. The UE may be a mobile phone. The UE may be a wearable device. The UE may be a sensor. The UE may be a stationary device.

The NW may be a base station. The NW may be an access point. The NW may be an eNB. The NW may be a gNB.

A RA procedure could be for small data transmission if the upper layer indicates a small data transmission. A RA procedure could be for small data transmission if the upper layer requests the resume of a suspended RRC connection for transmitting small data in RRC INACTIVE state.

During a RA procedure in NR, the UE uses a preamble within part of total <NUM> preambles to perform Msg1 (for <NUM>-step RA) and/or MSGA (for <NUM>-step RA) transmission to NW. The NW may recognize the RA types from the received preamble and then transmit corresponded Msg2 and/or MSGB to the UE. The RA types may include: <NUM>-step CBRA, <NUM>-step CBRA, <NUM>-step CFRA, and/or <NUM>-step CFRA. Based on the RA types, the UE should determine a preamble to use based on RA configurations provided by NW. The preamble may be assigned by the NW (e.g. for CFRA) or selected by the UE (e.g. for CBRA). The UE should select a preamble among the preambles allocated for the corresponding RA types. The RA parameters to indicate a partition of preambles corresponded to different RA types (e.g. <NUM>-step CBRA, <NUM>-step CBRA, <NUM>-step CFRA, <NUM>-step CFRA) are provided by RRC, as discussed in 3GPP R2-<NUM> and R2-<NUM>.

For Contention Free Random Access (CFRA), the NW assigns a dedicated preamble to the UE by Physical Downlink Control Channel (PDCCH) order (e.g. for Downlink (DL) data arrival) and/or RRC configurations (e.g. for handover). The dedicated preamble is part of CFRA preambles within the total <NUM> preambles. The UE uses the dedicated preamble to process Msg1 transmission and then Msg2 receiving in <NUM>-step RA. The UE uses the dedicated preamble to process MSGA transmission and then MSGB receiving in <NUM>-step RA.

For Contention Based Random Access (CBRA), the UE selects a preamble from part of CBRA preambles within the total <NUM> preambles. The UE uses the selected preamble to process Msg1 transmission, Msg2 receiving, Msg3 transmission and then Msg4 receiving in <NUM>-step RA. The UE uses the selected preamble to process MSGA transmission and then MSGB receiving in <NUM>-step RA.

The RO(s) are given in RA configurations by RRC (e.g. rach-ConfigGeneric, rach-ConfigGenericTwoStepRA as discussed in 3GPP R2-<NUM>) on a BWP. If the PRACH resources (e.g. msgA-PRACH-ConfigurationIndex as discussed in 3GPP R2-<NUM>) are not given in the <NUM>-step RA configuration (e.g. rach-ConfigGenericTwoStepRA), the <NUM>-step RA is considered to share the RO(s) with <NUM>-step RA on a BWP.

As shown in <FIG>, for the case of separated RO(s) between <NUM>-step and <NUM>-step RA, two RA parameters may be needed to determine the preambles that may be selected for the RA type of <NUM>-step RA. A first parameter (e.g. totalNumberOfRA-Preambles as discussed in 3GPP R2-<NUM>) may be used to indicate the total number of <NUM>-step CBRA and CFRA preambles. A second parameter (e.g. CB-PreamblesPerSSB in ssb perRACH OcasionAndCB-PreamblesPerSSB as discussed in 3GPP R2-<NUM>) may be used to indicate the number of <NUM>-step CBRA preambles. The <NUM>-step CBRA preambles start from zero to the second parameter minus one, and the <NUM>-step CFRA preambles start from the second parameter to the first parameter minus one.

As shown in <FIG>, for the case of separated RO(s) between <NUM>-step and <NUM>-step RA, two RA parameters may be needed to determine the preambles that may be selected for the RA type of <NUM>-step RA. There is a third parameter (e.g. msgA-totalNumberOfRA-Preambles [<NUM>]) to indicate the total number of <NUM>-step CBRA and CFRA preambles. There may be a forth parameter (e.g. CB-PreamblesPerSSB in msgA-ssb-perRACH-OcasionAndCB-PreamblesPerSSB as discussed in 3GPP R2-<NUM>) to indicate the number of <NUM>-step CBRA preambles. If the forth parameter is absent, the UE uses the second parameter as substitution. The <NUM>-step CBRA preambles start from zero to the forth parameter minus one, and the <NUM>-step CFRA preambles start from the forth parameter to the second parameter minus one.

As shown in <FIG>, for the case of shared RO(s) between <NUM>-step and <NUM>-step RA, three RA parameters may be needed to determine the preambles that may be selected for the RA type of <NUM>-step CBRA or <NUM>-step CBRA. There is a first parameter (e.g. totalNumberOfRA-Preambles as discussed in 3GPP R2-<NUM>) to indicate the total number of CBRA and CFRA preambles. There is a second parameter (e.g. CB-PreamblesPerSSB in ssb-perRACH-OcasionAndCB-PreamblesPerSSB) to indicate the number of <NUM>-step CBRA preambles. There is a fifth parameter (e.g. msgA-CB-PreamblesPerSSB-PerSharedRO as discussed in 3GPP R2-<NUM>) to indicate the number of <NUM>-step CBRA preambles. The <NUM>-step CBRA preambles start from zero to the second parameter minus one, the <NUM>-step CBRA preambles start from the second parameter to the second parameter plus the fifth parameter minus one, and the CFRA preambles starts from the second parameter plus the fifth parameter to the first parameter minus one.

During a RA procedure in LTE, the RA parameters to indicate a partition of preambles is provided by RRC, as discussed in 3GPP TS <NUM>. Currently <NUM>-step RA is not applicable in LTE. There are a sixth and a seventh parameters (e.g. firstPreamble and lastPreamble) to indicate the RA preambles except for EDT. There is an eighth parameter (e.g. edt-LastPreamble) to indicate the RA preambles for EDT. If RA with EDT is configured another PRACH resource (e.g. edt-PRACH-ParametersCE) different from PRACH resource (e.g. PRACH ParametersCE) for RA without EDT, the RA preambles for EDT start from the sixth parameter to the eighth parameter (shown in the upper part of <FIG>). Otherwise, the RA preambles for EDT start from the seventh parameter plus one to the eighth parameter (shown in as the lower part of <FIG>).

To enable RACH-based small data transmission in NR, RA preamble and/or RA resource partition between normal RA (e.g. not used for small data transmission) and SDT RA (e.g. used for small data transmission) may be needed. If both <NUM>-step RA and <NUM>-step RA are supported, RA preamble and/or RA resource partition between <NUM>-step RA and <NUM>-step RA may be needed.

During RA procedure for small data transmission in NR, two parameters may be needed to determine the RA preambles. There may be a ninth parameter to indicate the RA preambles for <NUM>-step small data transmission, and a tenth parameter to indicate the RA preambles for <NUM>-step small data transmission. The ninth and tenth parameters may be the number of preambles of <NUM>-step SDT RA and <NUM>-step SDT RA. The ninth and tenth parameters may be the last preamble number of <NUM>-step SDT RA and <NUM>-step SDT RA.

According to EDT in LTE, if the RA with early data and without early data have separated RO(s), the preambles for RA with early data start at the first preamble of preambles for RA without early data; otherwise (i.e. the RA with early data and without early data have shared RO(s)), the preambles for RA with early data start at the next preamble after the last preamble of preambles for RA without early data. If the RA with small data and without small data has separated RO(s), the preambles for <NUM>-step RA with small data start at the first preamble of preambles for <NUM>-step RA without small data, and the preambles for <NUM>-step RA with small data start at the first preamble of preambles for <NUM>-step RA without small data. If the RA with small data and without small data has shared RO(s), the preambles for <NUM>-step RA with small data start at the next preamble after the last preamble of preambles for <NUM>-step RA without small data, and the preambles for <NUM>-step RA with small data start at the next preamble after the last preamble of preambles for <NUM>-step RA without small data.

Considering small data transmission in NR, depending on whether the RO(s) between <NUM>-step RA and <NUM>-step RA is shared (or separated) and whether the RO(s) between RA with and without small data is shared (or separated), there may be four kinds of RO configuration cases as discussed below.

As shown in <FIG>, the RA preambles for <NUM>-step small data transmission may start from zero to the ninth parameter minus one (or to the ninth parameter). The RA preambles for <NUM>-step small data transmission may start from zero to the tenth parameter minus one (or to the tenth parameter).

As shown in <FIG>, the RA preambles for <NUM>-step small data transmission may start from the second parameter to the second parameter plus the ninth parameter minus one (or to the ninth parameter). The RA preambles for <NUM>-step small data transmission may start from the forth parameter to the forth parameter plus the tenth parameter minus one (or to the tenth parameter).

As shown in <FIG>, the RA preambles for <NUM>-step small data transmission may start from zero to the ninth parameter minus one (or to the ninth parameter). The RA preambles for <NUM>-step small data transmission may start from the second parameter to the second parameter plus the tenth parameter minus one (or to the tenth parameter).

As shown in <FIG>, the RA preambles for <NUM>-step small data transmission may start from the second parameter to the second parameter plus the ninth parameter minus one (or to the ninth parameter). The RA preambles for <NUM>-step small data transmission may start from the second parameter plus the fifth parameter to the second parameter plus the fifth parameter plus the tenth parameter minus one (or to the tenth parameter). However, in this situation, the preambles for <NUM>-step RA with small data may overlap with the preambles for <NUM>-step RA without small data. When the NW receives one of the preambles from this overlapped part, the NW could not recognize whether the UE performs a RA procedure for small data transmission or not and whether the RA procedure is <NUM>-step or <NUM>-step.

Throughout the present disclosure, the preamble may be the Random Access (RA) preamble. Throughout the present disclosure, preambles for a RA type are (a set of) preambles used for the RA type. The UE may use one of the preamble from preambles for a RA type to perform the RA procedure of the RA type.

Throughout the present disclosure, one, some, and/or all instances of "starting point" may correspond to, may be supplemented with and/or may be replaced by "starting position", "starting index". The starting point of preambles may be the first preamble index of the preambles.

To solve the issue, the UE and the NW need to have common understanding on how to interpret the parameters or configurations for RA preamble partitions. Based on the RA configurations provided by the NW on a BWP, the UE should unambiguously identify the preambles that can be used for a corresponding RA type (e.g. <NUM>-step or <NUM>-step, CB or CF, for small data transmission or not).

One method to solve the issue is that NW provides two parameters to indicate the preambles corresponding a RA type. NW may provide the two parameters for each RA type. One parameter may indicate the starting preamble for the RA type. The other parameter may indicate the ending preamble for the RA type (or the number of preambles for the RA type). For this method, some of the parameters may be redundant since the ending preamble for one RA type plus one may be the starting preamble for another RA type. To reduce the signalling overhead, parameter reuse may be considered among different RA types. However, depending on whether some RA type(s) is configured or not, how to reuse the parameter may be different. Some predefined rule(s) about how to interpret the parameters or configurations should be specified.

To solve the issue, the UE may need to identify which of the RA type(s) share the same RO(s). This may be based on the configuration of the RA type(s) provided by network. For example, if RO(s) of a specific RA type are not configured, it may imply that the RO(s) of the specific RA type are shared by other RA type(s). If more than one RA type shares the same RO(s), the UE may need to determine the order (or sequence) of the RA type(s) sharing the same RO(s) for the preamble partition. The order may be predefined (or hard-coded). And the UE could derive the starting point of a specific RA type based on the order. For example, the preamble range of the first RA type in the order may be from <NUM> to a value configured for the first RA type. And the preamble range of the second RA type in the order may be from the value configured for the first RA type plus one to the value configured for the second RA type, and so on.

One general concept of the invention is that the UE could identify (or interpret) the starting point of RA preambles corresponding to a RA type (e.g. a first RA type) based on one or more RA parameters for another RA type(s) (e.g. based on RA parameters of more than two RA types). Alternatively or additionally, the RA parameter of which RA type is used to derive the starting point of RA preamble corresponding to the RA type (e.g. the first RA type) may depend on whether one or more RA types are configured by the NW. This may be applied for the case that the different types of RA (e.g. <NUM>-step and/or <NUM>-step RAs with and/or without small data) share the same RO(s).

For example, the UE could identify (or interpret) the starting point of RA preambles for small data transmission differently according to the RA configurations provided by the NW on a BWP. The NW may configure <NUM>-step RA without small data, <NUM>-step RA without small data, <NUM>-step RA with small data, and/or <NUM>-step RA with small data on a BWP. The NW may configure a ninth parameter in the RA configurations for <NUM>-step small data transmission on a BWP. The NW may configure a tenth parameter in the RA configurations for <NUM>-step small data transmission on a BWP.

The different types of RA may share the same RO(s) when the NW does not configure another PRACH resources. The different types of RA may share the same RO(s) when the PRACH resources are not enough. The different types of RA may share the same RO(s) when the NW considers another PRACH resource to be unnecessary.

For the RA configurations without small data with shared RO(s), there may be both <NUM>-step and <NUM>-step RA configurations on a BWP. For the RA configurations without small data with shared RO(s), there may be only <NUM>-step RA configuration on a BWP. For the RA configurations with small data with shared RO(s), there may be both <NUM>-step and <NUM>-step RA configurations on a BWP. For the RA configurations with small data with shared RO(s), there may be only <NUM>-step RA configuration on a BWP. For the RA configurations with small data with shared RO(s), there may be only <NUM>-step RA configuration on a BWP.

The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter. The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the fifth parameter. The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the fifth parameter plus the tenth parameter (or at the tenth parameter plus one). The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the tenth parameter (or at the tenth parameter plus one). The UE may identify (or interpret) the ending point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the ninth parameter (or at the starting point plus the ninth parameter minus one).

The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter. The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the fifth parameter. The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the fifth parameter plus the ninth parameter (or at the ninth parameter plus one). The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the second parameter plus the ninth parameter (or at the ninth parameter plus one). The UE may identify (or interpret) the ending point of <NUM>-step RA preambles for small data transmission with shared RO(s) at the tenth parameter (or at the starting point plus the tenth parameter minus one).

<FIG> is a table showing examples of examples of preamble starting points for small data transmission with shared RO(s) according to one exemplary embodiment. The following are some examples shown in <FIG>.

In one example, there may be configurations of <NUM>-step RA without small data, <NUM>-step RA without small data, and <NUM>-step RA with small data on a BWP. And the three types of RA share the same RO(s). The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter. The example is shown in <FIG>.

In one example, there may be configurations of <NUM>-step RA without small data, <NUM>-step RA without small data, and <NUM>-step RA with small data on a BWP. And the three types of RA share the same RO(s). The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter.

In one example, there may be configurations of <NUM>-step RA without small data, <NUM>-step RA without small data, <NUM>-step RA with small data, and <NUM>-step RA with small data on a BWP. And the four types of RA share the same RO(s).

Example 3a: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter, and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter plus the ninth parameter (or at the ninth parameter plus one). The example is shown in <FIG>.

Example 3b: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter plus the tenth parameter (or at the tenth parameter plus one), and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter. The example is shown in <FIG>.

Example 3c: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter, and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus the ninth parameter (or at the ninth parameter plus one). The example is shown in <FIG>.

Example 3d: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus the tenth parameter (or at the tenth parameter plus one), and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter.

Example 3e: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter, and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter plus the ninth parameter (or at the ninth parameter plus one plus the fifth parameter). The example is shown in <FIG>.

Example 3f: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus fifth parameter plus the tenth parameter (or at the tenth parameter plus one plus the fifth parameter), and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter.

In one example, there may be configurations of <NUM>-step RA without small data, and <NUM>-step RA with small data on a BWP. And the two types of RA share the same RO(s). The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter.

In one example, there may be configurations of <NUM>-step RA without small data, <NUM>-step RA with small data, and <NUM>-step RA with small data on a BWP. And the three types of RA share the same RO(s).

Example 6a: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter, and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus the ninth parameter (or at the ninth parameter plus one). The example is shown in <FIG>.

Example 6b: The UE may identify (or interpret) the starting point of <NUM>-step RA preambles for small data transmission at the second parameter plus the tenth parameter (or at the tenth parameter plus one), and the starting point of <NUM>-step RA preambles for small data transmission at the second parameter.

The UE may receive some configurations related to RA resources for small data transmission provided by the NW. For example, the RA configurations may include some parameters to indicate the preambles for <NUM>-step and/or <NUM>-step small data transmission. For example, the RA configurations may include some parameters and/or occasions to indicate whether the different types of RA share the same RO(s). The RA configurations may be provided in system information, RRC signaling, and/or MAC CE.

The above method(s) to identify (or interpret) the starting point of RA preambles for a specific RA type could be applied by a UE and/or a network node. Since the UE and the NW should have common understanding on the RA preamble partitions corresponding to different RA types, the UE and the NW should apply the same method to identify (or interpret) the RA preamble partitions based on the RA configuration(s) provided by the NW (on a BWP).

The RA types may be categorized by whether it is for <NUM>-step RA or <NUM>-step RA, and/or whether it is for SDT (i.e. small data transmission). The RA type for SDT may be the RA procedure with small data. The RA type for SDT may be the small data transmission using RA. The RA type for SDT may be a RA type initiated in RRC_INACTIVE state. The RA type for SDT may be the RA procedure in RRC _INACTIVE state to transmit UL user data (from DRB or data channel).

The RA types may be (or comprise, or include):.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receives a configuration, from a network node, indicating that Random Access Channel (RACH) occasion(s) of a first Random Access (RA) type are not configured. In step <NUM>, the UE determines if RACH occasion(s) of the first RA type are shared with a second RA type or a third RA type.

Preferably, the UE could determine if RACH occasion(s) (RO(s)) of the first RA type are shared with a second RA type or a third RA type based on a parameter (or indication) indicating that first RA type uses (or shares) RO(s) of the second RA type or the third RA type. In a second claimed option the UE determines if RO(s) of the first RA type are shared with a second RA type or a third RA type based on a predefined rule. The predefined rule may comprise: (i) the first RA type does not use (or share) RO(s) of the second RA type; and (ii) the first RA type uses (or shares) RO(s) of the third RA type.

Preferably, the first, the second, or the third RA type may be <NUM>-step RA without small data, <NUM>-step RA without small data, <NUM>-step with small data, or <NUM>-step with small data. The small data may be uplink data transmitted in RRC_INACTIVE state.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE. The UE <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE (i) to receive a configuration, from a network node, indicating that RACH occasion(s) of a first RA type are not configured, and (ii) to determine if RACH occasion(s) of the first RA type are shared with a second RA type or a third RA type. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receiving a configuration indicating that Random Access Channel (RACH) occasion(s) of a first Random Access (RA) type are shared with at least a second RA type and a third RA type. In step <NUM>, the UE derives starting point of preambles for the first RA type based on at least RA parameter(s) for more than one RA type.

Preferably, the starting point of preambles for the first RA type may be summation of preamble ranges of the more than one RA type. The preamble ranges of the more than one RA type may be provided in the configuration.

Preferably, the UE could select a RA preamble from the preambles for the first RA type, and could transmit the RA preamble.

Preferably, the first, the second, or the third RA type may be <NUM>-step RA without small data, <NUM>-step RA without small data, <NUM>-step with small data, or <NUM>-step with small data. The small data may be uplink data transmitted in RRC _INACTIVE state.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE. The UE <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE (i) to receive a configuration indicating that RACH occasion(s) of a first RA type are shared with at least a second RA type and a third RA type, and (ii) to derive starting point of preambles for the first RA type based on at least RA parameter(s) for more than one RA type. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receives a configuration, from a network node, indicating that whether RO(s) of a first RA type are shared with a second RA type or a third RA type. In step <NUM>, the UE initiates a RA procedure with the first RA type using the RO(s) of the first RA type.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE. The UE <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> (i) to receive a configuration, from a network node, indicating that whether RO(s) of a first RA type are shared with a second RA type or a third RA type, and (ii) to initiate a RA procedure with the first RA type using the RO(s) of the first RA type. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a network (NW). In step <NUM>, the network provides a configuration, to a UE, indicating whether RO(s) of a first RA type are shared with a second RA type or a third RA type.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a network. The network <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to provide a configuration, to a UE, indicating whether RO(s) of a first RA type are shared with a second RA type or a third RA type. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

In the context of the embodiments shown in <FIG> and <FIG> and discussed above, the configuration may be an explicit configuration preferably. The configuration may include a parameter (or an indication) indicating that whether RO(s) of the first RA type are shared with the second RA type or the third RA type. The parameter (or the indication) may indicate that RO(s) of the first RA type uses (or shares) RO(s) of the second RA type or the third RA type by a specific parameter. The parameter (or the indication) may be present (or provided or received) if the first RA type does not have its own RO configuration(s). On the other hand, the parameter (or the indication) may be absent (or not provided or not received) if the first RA type has its own RO configuration(s). The parameter (or the indication) may be configured in the RRC configurations of the first RA type, the second RA type and/or the third RA type. The parameter (or the indication) may be a Boolean, an enumerated, and/or an integer.

Preferably, the configuration may be an implicit configuration. The configuration may indicate the first RA type uses (or shares) RO(s) of the second or the third RA type by the presence or absence of one or more specific parameters, configurations, and/or information elements. The configuration may indicate the first RA type uses (or shares) RO(s) of the second or the third RA type by which parameter, configuration, and/or information element includes the RO configuration(s) of the first RA type. The configuration may indicate the first RA type uses (or shares) RO(s) of the second or the third RA type by configuring the RO configuration(s) of the first RA type in different information elements and/or in (or at) different parameters in an information element. The parameter (or the indication) may be provided in a RRC message. The RRC message may be a common signaling, a dedicated signaling, system information, dedicated RRC message, RRC reconfiguration message, and/or handover command.

Preferably, the UE may be a NR device and/or a NR-light device. The UE may be a reduced capability device and/or a stationary device. The UE may be a mobile phone, a wearable device, and/or a sensor. The UE may have mobility capability, or no mobility capability.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a network (NW). In step <NUM>, the network provides a configuration of RO(s) of a first RA type, wherein the configuration is not allowed to indicate that RO(s) of the first RA type are shared with a second RA type.

Preferably, the configuration may be allowed to indicate that RO(s) of the first RA type are shared with a third RA type. The first RA type may be unable to directly share the RO(s) with more than one RA type (e.g. the second or third RA type). The first RA type may be (or may include) <NUM>-step RA for small data transmission, or <NUM>-step RA for small data transmission. The second RA type may be (or may include) <NUM>-step RA without small data transmission, <NUM>-step RA without small data transmission, <NUM>-step RA with small data transmission, or <NUM>-step RA with small data transmission. The third RA type may be (or may include) <NUM>-step RA without small data transmission, <NUM>-step RA without small data transmission, <NUM>-step RA with small data transmission, or <NUM>-step RA with small data transmission. Preferably, the second and/or third RA type may be different from the first RA type.

Preferably, the small data transmission may be initiated upon the upper layer indicates a RRC resume procedure for small data transmission. The small data transmission may also be initiated upon the upper layer requests the resume of a suspended RRC connection for transmitting small data in RRC INACTIVE state.

Preferably, the RO(s) of a RA type other than the first RA type may be shared by the first RA type when the first RA type does not have its own RO configuration(s). The RO(s) of a RA type other than the first RA type may be shared by the first RA type when the RO(s) of the first RA type are not configured. The RO configuration(s) of a RA type may be included in an information element and/or a group of parameters. The RO(s) may be shared when the NW configures the same PRACH resources for more than one RA type. The RO(s) may be shared when the PRACH resources are not enough for more than one RA type. The RO(s) may be shared when the NW supposes separated PRACH resources for more than one RA type to be unnecessary. The NW may be a network node, a base station, an access point, an eNB, and/or a gNB.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a network. The network <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE to provide a configuration of RO(s) of a first RA type, wherein the configuration is not allowed to indicate that RO(s) of the first RA type is shared with a second RA type. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE initiates a RA procedure with a first RA type. In step <NUM>, the UE selects a RA preamble for transmission from a set of RA preambles corresponding to the first RA type, wherein the starting point of the set of RA preambles corresponding to the first RA type is derived based on RA parameters for more than one RA type other than the first RA type.

Preferably, the first RA type may be <NUM>-step and/or <NUM>-step RA for small data transmission. The first RA type (e.g. a first RA type) could share RO(s) with the at least a RA type other than the first RA type. The at least a RA type other than the first type may be <NUM>-step RA without small data, <NUM>-step RA without small data, <NUM>-step RA with small data, and/or <NUM>-step RA with small data.

Preferably, the RA procedure for the RA type may be contention-based. The small data transmission could be initiated upon the upper layer indicates a RRC resume procedure for small data transmission. The small data transmission could be initiated upon the upper layer requests the resume of a suspended RRC connection for transmitting small data in RRC_INACTIVE state.

Preferably, the RO(s) may be shared with other RA types when the NW configures the same PRACH resources for more than one RA type, when the PRACH resources are not enough for more than one RA type, and/or when the NW supposes separated PRACH resources for more than one RA type to be unnecessary. The RA parameters for <NUM>-step RA without small data may be a first parameter and/or a second parameter to determine the RA preambles for <NUM>-step CBRA and CFRA. The RA parameters for <NUM>-step RA without small data may be a third parameter, a fourth parameter, and/or a fifth parameter to determine the RA preambles for <NUM>-step CBRA and CFRA. The RA parameters for RA with small data may be a ninth parameter and/or a tenth parameter to determine the RA preambles for <NUM>-step and <NUM>-step RA.

Preferably, the first parameter, second parameter, third parameter, fourth parameter, and/or fifth parameter may indicate the number of preambles for the RA types. The ninth parameter and/or tenth parameter may indicate the number of preambles for the RA types, and/or the last preamble number for the RA types. The RA parameters and RO(s) may be provided by the NW in RA configurations.

Preferably, the starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) may be at the second parameter plus the fifth parameter plus the tenth parameter, at the second parameter plus the tenth parameter, or at the tenth parameter plus one. The starting point of <NUM>-step RA preambles for small data transmission with shared RO(s) may be at the second parameter plus the fifth parameter, at the second parameter plus the fifth parameter plus the ninth parameter, at the second parameter plus the ninth parameter, or at the ninth parameter plus one.

Preferably, the UE could transmit the RA preamble during the RA procedure. The RA preamble could identify that the RA procedure is with the first RA type.

Various aspects of the disclosure have been described above. It should be apparent that the teachings herein could be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein could be implemented independently of any other aspects and that two or more of these aspects could be combined in various ways. For example, an apparatus could be implemented or a method could be practiced using any number of the aspects set forth herein. In addition, such an apparatus could be implemented or such a method could be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. As an example of some of the above concepts, in some aspects concurrent channels could be established based on pulse repetition frequencies. In some aspects concurrent channels could be established based on pulse position or offsets. In some aspects concurrent channels could be established based on time hopping sequences. In some aspects concurrent channels could be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

Those of skill would further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as "software" or a "software module"), or combinations of both.

It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

Claim 1:
A method for a UE, comprising:
receiving a configuration, from a network node, indicating that a first <NUM>-step Random Access, in the following also referred to as RA, for small data shares Random Access Channel, in the following also referred to as RACH, occasion/s of other RA (<NUM>), wherein RACH occasion/s of the first <NUM>-step RA for small data are not configured separately; and
determining whether the first <NUM>-step RA for small data shares RACH occasion/s of a second <NUM>-step RA or a <NUM>-step RA (<NUM>),
wherein
the UE determines whether the first <NUM>-step RA for small data shares RACH occasion/s of the second <NUM>-step RA or the <NUM>-step RA based on a first parameter or indication explicitly indicating RACH occasion/s of which RA amongst the second <NUM>-step RA and the <NUM>-step RA the first <NUM>-step RA for small data uses or shares or based on whether a second parameter is present or absent.