This disclosure generally relates to wireless communication networks, and more particularly, to a method and apparatus for Small Data Transmission (SDT) procedure in a wireless communication system.
With the rapid rise in demand for communication of large amounts of data to and from mobile communication devices, traditional mobile voice communication networks are evolving into networks that communicate with Internet Protocol (IP) data packets. Such IP data packet communication can provide users of mobile communication devices with voice over IP, multimedia, multicast and on-demand communication services.
An exemplary network structure is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can provide high data throughput in order to realize the above-noted voice over IP and multimedia services. A new radio technology for the next generation (e.g., 5G) is currently being discussed by the 3GPP standards organization. Accordingly, changes to the current body of 3GPP standard are currently being submitted and considered to evolve and finalize the 3GPP standard.
A method and device are disclosed from the perspective of a User Equipment (UE). In one embodiment, the method includes the UE receiving a first Physical Downlink Control Channel (PDCCH)-related configuration in system information. The method further includes the UE initiating a Small Data Transmission (SDT) procedure in RRC_INACTIVE state, wherein the SDT procedure comprises a Random Access (RA) procedure and at least one subsequent transmission after the RA procedure. The method also includes the UE monitoring PDCCH, based on the first PDCCH-related configuration, during the RA procedure in RRC_INACTIVE state. In addition, the method includes the UE monitoring the PDCCH, based on a second PDCCH-related configuration, for the at least one subsequent transmission in RRC_INACTIVE state if the second PDCCH-related configuration is received by the UE.
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: TS 38.300 V16.2.0, “NR, NR and NG-RAN overall description, Stage 2”; TS 38.321 V16.1.0, “NR, Medium Access Control (MAC) protocol specification”; TS 38.331 V16.1.0, “NR, Radio Resource Control (RRC) protocol specification”; RP-193252, “Work Item on NR small data transmissions in INACTIVE state”, ZTE Corporation; 3GPP RAN2 #111 meeting minutes; and TS 38.213 V16.2.0, “NR, Physical layer procedures for control”. The standards and documents listed above are hereby expressly incorporated by reference in their entirety.
Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access network. In the embodiment, antenna groups each are designed to communicate to access terminals in a sector of the areas covered by access network 100.
In communication over forward links 120 and 126, the transmitting antennas of access network 100 may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals 116 and 122. 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.
In one embodiment, each data stream is transmitted over a respective transmit antenna. TX data processor 214 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 230.
The modulation symbols for all data streams are then provided to a TX MIMO processor 220, which may further process the modulation symbols (e.g., for OFDM). TX MIMO processor 220 then provides NT modulation symbol streams to NT transmitters (TMTR) 222a through 222t. In certain embodiments, TX MIMO processor 220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.
Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NT modulated signals from transmitters 222a through 222t are then transmitted from NT antennas 224a through 224t, respectively.
At receiver system 250, the transmitted modulated signals are received by NR antennas 252a through 252r and the received signal from each antenna 252 is provided to a respective receiver (RCVR) 254a through 254r. Each receiver 254 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.
An RX data processor 260 then receives and processes the NR received symbol streams from NR receivers 254 based on a particular receiver processing technique to provide NT “detected” symbol streams. The RX data processor 260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor 260 is complementary to that performed by TX MIMO processor 220 and TX data processor 214 at transmitter system 210.
A processor 270 periodically determines which pre-coding matrix to use (discussed below). Processor 270 formulates a reverse link message comprising a matrix index portion and a rank value portion.
The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 238, which also receives traffic data for a number of data streams from a data source 236, modulated by a modulator 280, conditioned by transmitters 254a through 254r, and transmitted back to transmitter system 210.
At transmitter system 210, the modulated signals from receiver system 250 are received by antennas 224, conditioned by receivers 222, demodulated by a demodulator 240, and processed by a RX data processor 242 to extract the reserve link message transmitted by the receiver system 250. Processor 230 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.
Turning to
3GPP TS 38.300 and TS 38.331 provide the following description related to RRC_INACTIVE state in New RAT/Radio (NR):
RRC_INACTIVE is a state where a UE remains in CM-CONNECTED and can move within an area configured by NG-RAN (the RNA) without notifying NG-RAN. In RRC_INACTIVE, the last serving gNB node keeps the UE context and the UE-associated NG connection with the serving AMF and UPF.
[ . . . ]
At transition to RRC_INACTIVE the NG-RAN node may configure the UE with a periodic RNA Update timer value. At periodic RNA Update timer expiry without notification from the UE, the gNB behaves as specified in TS 23.501 [3].
If the UE accesses a gNB other than the last serving gNB, the receiving gNB triggers the XnAP Retrieve UE Context procedure to get the UE context from the last serving gNB and may also trigger an Xn-U Address Indication procedure including tunnel information for potential recovery of data from the last serving gNB. Upon successful UE context retrieval, the receiving gNB shall perform the slice-aware admission control in case of receiving slice information and becomes the serving gNB and it further triggers the NGAP Path Switch Request and applicable RRC procedures. After the path switch procedure, the serving gNB triggers release of the UE context at the last serving gNB by means of the XnAP UE Context Release procedure.
In case the UE is not reachable at the last serving gNB, the gNB shall fail any AMF initiated UE-associated class 1 procedure which allows the signalling of unsuccessful operation in the respective response message. It may trigger the NAS Non Delivery Indication procedure to report the non-delivery of any NAS PDU received from the AMF.
If the UE accesses a gNB other than the last serving gNB and the receiving gNB does not find a valid UE Context, the receiving gNB can perform establishment of a new RRC connection instead of resumption of the previous RRC connection. UE context retrieval will also fail and hence a new RRC connection needs to be established if the serving AMF changes.
A UE in the RRC_INACTIVE state is required to initiate RNA update procedure when it moves out of the configured RNA. When receiving RNA update request from the UE, the receiving gNB triggers the XnAP Retrieve UE Context procedure to get the UE context from the last serving gNB and may decide to send the UE back to RRC_INACTIVE state, move the UE into RRC_CONNECTED state, or send the UE to RRC_IDLE. In case of periodic RNA update, if the last serving gNB decides not to relocate the UE context, it fails the Retrieve UE Context procedure and sends the UE back to RRC_INACTIVE, or to RRC_IDLE directly by an encapsulated RRCRelease message.
A UE in RRC_INACTIVE performs cell reselection. The principles of the procedure are as for the RRC_IDLE state (see clause 9.2.1.2).
9.2.2.4.1 UE Triggered Transition from RRC_INACTIVE to RRC_CONNECTED
The following figure describes the UE triggered transition from RRC_INACTIVE to RRC_CONNECTED in case of UE context retrieval success:
[FIG. 9.2.2.4.1-1 of 3GPP TS 38.300 V16.2.0, entitled “UE triggered transition from RRC_INACTIVE to RRC_CONNECTED (UE context retrieval success)”, is reproduced as
3. The last serving gNB provides UE context data.
[FIG. 9.2.2.4.1-2 of 3GPP TS 38.300 V16.2.0, entitled “UE triggered transition from RRC_INACTIVE to RRC_CONNECTED (UE context retrieval failure)”, is reproduced as
A UE is either in RRC_CONNECTED state or in RRC_INACTIVE state when an RRC connection has been established. If this is not the case, i.e. no RRC connection is established, the UE is in RRC_IDLE state. The RRC states can further be characterised as follows:
[FIG. 5.3.8.1-1 of 3GPP TS 38.331 V16.1.0, entitled “RRC connection release, successful”, is reproduced as
The purpose of this procedure is:
The network initiates the RRC connection release procedure to transit a UE in RRC_CONNECTED to RRC_IDLE; or to transit a UE in RRC_CONNECTED to RRC_INACTIVE only if SRB2 and at least one DRB or, for IAB, SRB2, is setup in RRC_CONNECTED; or to transit a UE in RRC_INACTIVE back to RRC_INACTIVE when the UE tries to resume; or to transit a UE in RRC_INACTIVE to RRC_IDLE when the UE tries to resume. The procedure can also be used to release and redirect a UE to another frequency.
The UE shall:
The purpose of this procedure is to resume a suspended RRC connection, including resuming SRB(s) and DRB(s) or perform an RNA update.
The UE initiates the procedure when upper layers or AS (when responding to RAN paging, upon triggering RNA updates while the UE is in RRC_INACTIVE, or for sidelink communication as specified in sub-clause 5.3.13.1a) requests the resume of a suspended RRC connection.
The UE shall ensure having valid and up to date essential system information as specified in clause 5.2.2.2 before initiating this procedure.
Upon initiation of the procedure, the UE shall:
The UE shall set the contents of RRCResumeRequest or RRCResumeRequest1 message as follows:
The UE shall:
The UE shall:
3GPP TS 38.331 provides the following description related to Radio Resource Control (RRC) parameters and configurations in NR:
MIB
The MIB includes the system information transmitted on BCH.
Signalling radio bearer: N/A
RLC-SAP: TM
Logical channel: BCCH
Direction: Network to UE
SIB1
SIB1 contains information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other system information. It also contains radio resource configuration information that is common for all UEs and barring information applied to the unified access control.
Signalling radio bearer: N/A
RLC-SAP: TM
Logical channels: BCCH
Direction: Network to UE
ServingCellConfigCommonSIB
The IE ServingCellConfigCommonSIB is used to configure cell specific parameters of a UE's serving cell in SIB1.
DownlinkConfigCommonSIB
The IE DownlinkConfigCommonSIB provides common downlink parameters of a cell.
BWP-DownlinkCommon
The IE BWP-DownlinkCommon is used to configure the common parameters of a downlink BWP. They are “cell specific” and the network ensures the necessary alignment with corresponding parameters of other UEs. The common parameters of the initial bandwidth part of the PCell are also provided via system information. For all other serving cells, the network provides the common parameters via dedicated signalling.
PDCCH-ConfigCommon
The IE PDCCH-ConfigCommon is used to configure cell specific PDCCH parameters provided in SIB as well as in dedicated signalling.
PDSCH-ConfigCommon
The IE PDSCH-ConfigCommon is used to configure cell specific PDSCH parameters.
UplinkConfigCommonSIB
The IE UplinkConfigCommonSIB provides common uplink parameters of a cell.
BWP-UplinkCommon
The IE BWP-UplinkCommon is used to configure the common parameters of an uplink BWP. They are “cell specific” and the network ensures the necessary alignment with corresponding parameters of other UEs. The common parameters of the initial bandwidth part of the PCell are also provided via system information. For all other serving cells, the network provides the common parameters via dedicated signalling.
PUSCH-ConfigCommon
The IE PUSCH-ConfigCommon is used to configure the cell specific PUSCH parameters.
BWP-DownlinkDedicated
The IE BWP-DownlinkDedicated is used to configure the dedicated (UE specific) parameters of a downlink BWP.
PDCCH-Config
The IE PDCCH-Config is used to configure UE specific PDCCH parameters such as control resource sets (CORESET), search spaces and additional parameters for acquiring the PDCCH. If this IE is used for the scheduled cell in case of cross carrier scheduling, the fields other than searchSpacesToAddModList and searchSpacesToReleaseList are absent. If the IE is used for a dormant BWP, the fields other than controlResourceSetToAddModList and controlResourceSetToReleaseList are absent.
PDSCH-Config
The PDSCH-Config IE is used to configure the UE specific PDSCH parameters.
BWP-UplinkDedicated
The IE BWP-UplinkDedicated is used to configure the dedicated (UE specific) parameters of an uplink BWP.
PUSCH-Config
The IE PUSCH-Config is used to configure the UE specific PUSCH parameters applicable to a particular BWP.
ControlResourceSet
The IE ControlResourceSet is used to configure a time/frequency control resource set (CORESET) in which to search for downlink control information (see TS 38.213 [13], clause 10.1).
ServingCellConfig
The IE ServingCellConfig is used to configure (add or modify) the UE with a serving cell, which may be the SpCell or an SCell of an MCG or SCG. The parameters herein are mostly UE specific but partly also cell specific (e.g. in additionally configured bandwidth parts). Reconfiguration between a PUCCH and PUCCHless SCell is only supported using an SCell release and add.
CSI-MeasConfig
The IE CSI-MeasConfig is used to configure CSI-RS (reference signals) belonging to the serving cell in which CSI-MeasConfig is included, channel state information reports to be transmitted on PUCCH on the serving cell in which CSI-MeasConfig is included and channel state information reports on PUSCH triggered by DCI received on the serving cell in which CSI-MeasConfig is included. See also TS 38.214 [19], clause 5.2.
CSI-ReportConfig
The IE CSI-ReportConfig is used to configure a periodic or semi-persistent report sent on PUCCH on the cell in which the CSI-ReportConfig is included, or to configure a semi-persistent or aperiodic report sent on PUSCH triggered by DCI received on the cell in which the CSI-ReportConfig is included (in this case, the cell on which the report is sent is determined by the received DCI). See TS 38.214 [19], clause 5.2.1.
PUCCH-Config
The IE PUCCH-Config is used to configure UE specific PUCCH parameters (per BWP).
SRS-Config
The IE SRS-Config is used to configure sounding reference signal transmissions or to configure sounding reference signal measurements for CLI. The configuration defines a list of SRS-Resources and a list of SRS-ResourceSets. Each resource set defines a set of SRS-Resources. The network triggers the transmission of the set of SRS-Resources using a configured aperiodicSRS-ResourceTrigger (L1 DCI).
3GPP RP-193252 and 3GPP RAN2 #111 meeting minutes provide the following description related to NR small data transmissions in RRC_INACTIVE state:
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-16, 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.
[ . . . ]
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, 2-step, 4-step RACH and configured grant type-1 have already been specified as part of Rel-15 and Rel-16. 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:
3GPP TS 38.213 provides the following description related to Channel State Information (CSI) reporting:
9.2 UCI reporting in physical uplink control channel
UCI types reported in a PUCCH include HARQ-ACK information, SR, LRR, and CSI. UCI bits include HARQ-ACK information bits, if any, SR information bits, if any, LRR information bit, if any, and CSI bits, if any. The HARQ-ACK information bits correspond to a HARQ-ACK codebook as described in Clause 9.1. For the remaining of this clause, any reference to SR is applicable for SR and/or for LRR.
If a UE does not have dedicated PUCCH resource configuration, provided by PUCCH-ResourceSet in PUCCH-Config, a PUCCH resource set is provided by pucch-ResourceCommon through an index to a row of Table 9.2.1-1 for transmission of HARQ-ACK information on PUCCH in an initial UL BWP of NBWPsize PRBs.
The PUCCH resource set includes sixteen resources, each corresponding to a PUCCH format, a first symbol, a duration, a PRB offset RBBWPoffset, and a cyclic shift index set for a PUCCH transmission.
The UE transmits a PUCCH using frequency hopping if not provided useInterlacePUCCH-PUSCH in BWP-UplinkCommon; otherwise, the UE transmits a PUCCH without frequency hopping.
An orthogonal cover code with index 0 is used for a PUCCH resource with PUCCH format 1 in Table 9.2.1-1.
The UE transmits the PUCCH using the same spatial domain transmission filter as for a PUSCH transmission scheduled by a RAR UL grant as described in Clause 8.3.
In general, the RRC_INACTIVE state was introduced for UEs with infrequent data transmission. When there is no data transmission, the UE could be put into RRC_INACTIVE state (i.e. the RRC connection is suspended) for reducing power consumption. The current serving gNB would store (or maintain) the UE context (e.g. configurations and identities of the UE) for the UE while the UE is in RRC_INACTIVE state. Upon data arrival, the UE could resume the RRC connection from RRC_INACTIVE state, which is faster than establishing a new RRC connection from RRC_IDLE state. After resuming the RRC connection (e.g. after successful completion of a RA procedure), the UE is able to transmit data (e.g. data from application layer) in RRC_CONNECTED state as usual.
In addition, the UE is able to resume the Radio Resource Control (RRC) connection on a different gNB (i.e. new gNB) than the original gNB (i.e. old gNB) in which the RRC connection was suspended. In this case, the new gNB tries to retrieve the UE context from the old gNB. If the new gNB fails to retrieve the UE context, fallback to RRC connection setup procedure may take place (i.e. establishing a new RRC connection). When RRC connection of a UE is suspended, the UE will store (part of) its current RRC configuration in the “UE Inactive AS context”. After a UE initiates the RRC Resume procedure on a Cell (which will be considered as the SpCell after the RRC connection is successfully resumed in this Cell) and before the UE transmits the RRCResumeRequest message, the UE will restore part of the stored RRC configuration from the UE Inactive AS context, as specified in Section 5.3.13.3 of 3GPP TS 38.331. More details for RRC_INACTIVE state are provided above and could be found in 3GPP TS 38.300 and TS 38.331.
Although the RRC_INACTIVE state brings benefit as stated above, currently the UE is not able to transmit (user-plane) data in RRC_INACTIVE state. That is, the UE needs to enter RRC_CONNECTED state before transmitting the data. After transmitting the data, the UE is put into RRC_INACTIVE state again. The above steps happen for each data transmission regardless of the amount of data and how frequent the data arrives, which may result in power consumption and signaling overhead.
To mitigate the problem, small data transmission in RRC_INACTIVE state is to be introduced, as discussed in 3GPP RP-193252. In general, the main objective of small data transmission is to enable the UE to transmit data in RRC_INACTIVE state without (or before) entering RRC_CONNECTED state. Possible solutions may be based on 2-step RACH, 4-step RACH, and/or pre-configured PUSCH resources (e.g. similar to Type-1 configured grant in NR). Small data transmission in RRC_INACTIVE state may be referred to as “SDT in RRC_INACTIVE state” and/or “SDT procedure” and/or “SDT”.
For example, when a UE performs 2-step RACH based SDT procedure in a Cell, the UE includes Uplink (UL) data together with a RRCResumeRequest message in the MsgA. For example, when a UE performs 4-step Random Access Channel (RACH) based SDT procedure in a Cell, the UE includes UL data together with a RRCResumeRequest message in the Msg3. For example, when a UE performs pre-configured Physical Uplink Shared Channel (PUSCH) resources based SDT procedure in a Cell, the UE includes UL data together with a RRCResumeRequest message in the Protocol Data Unit (PDU) to be transmitted using the pre-configured PUSCH resources. It is possible that a new RRC message is introduced for the SDT procedure (replacing the RRCResumeRequest message as mentioned above). It may be possible that the UL data is transmitted without a RRC message.
Typically, the data transmission of a SDT procedure comprises a first UL transmission (e.g. the Msg3 of a 4-step RACH or the MsgA of a 2-step RACH) followed by a first Downlink (DL) transmission (e.g. the Msg4 of a 4-step RACH or the MsgB of a 2-step RACH). If there is more data which could not be transmitted/received within the first UL/DL transmission, the network may transit the UE into RRC_CONNECTED state for transmitting/receiving the more data. It is possible that subsequent transmission(s) could take place while the UE is still in RRC_INACTIVE state.
For example, a second UL transmission could follow the first DL transmission and the UE could stay in RRC_INACTIVE after performing the second UL transmission (and receiving “ACK” response from the network). For example, a second DL transmission could follow the second UL transmission and the UE could stay in RRC_INACTIVE after performing the second DL transmission (and transmitting “ACK” to the network). “The completion of a SDT procedure” could refer to the last transmission (e.g. the second UL transmission or the second DL transmission as described above) of the subsequent transmission(s). The RRCRelease message could be included in the first DL transmission rather than the second DL transmission in case the second DL transmission is the last DL transmission in a SDT procedure.
Alternatively, the RRCRelease message could be included in the second DL transmission rather than the first DL transmission in case the second DL transmission is the last DL transmission in a SDT procedure. The subsequent transmission(s) could be considered as part of the SDT procedure. The network could indicate, in the first DL transmission, whether there is subsequent transmission(s) in a SDT procedure. The network could indicate, in the first DL transmission, whether the UE is allowed to perform subsequent transmission(s) in a SDT procedure. The subsequent transmission(s) in a SDT procedure may comprise at least one UL transmission. The subsequent transmission(s) in a SDT procedure may comprise at least one DL transmissions. In case there is subsequent transmission(s), the second UL transmission in a SDT procedure may also be referred to as the first subsequent UL transmission (and so on). In case there is subsequent transmission(s), the second DL transmission in a SDT procedure may also be referred to as the first subsequent DL transmission (and so on).
A SDT procedure referred in the following paragraph could comprise a RA procedure for SDT and the subsequent transmission(s) (after the RA procedure). The subsequent transmission(s) could be scheduled by the network with dynamic uplink grant or downlink assignment (via PDCCH). The subsequent transmission(s) could be scheduled by the network without dynamic uplink grant (e.g. the subsequent transmission(s) via configured grant).
During the RRC Resume procedure (e.g. a Random Access (RA) procedure) on a Cell, the UE monitors Physical Downlink Control Channel (PDCCH) based on the PDCCH-related configuration provided in System Information (e.g. MIB, SIB1) of the Cell. In response to successful reception of RRCResume message, the UE may restore the PDCCH-related configuration from its stored UE Inactive Access Stratum (AS) context, and the network may also provide PDCCH-related configuration in the RRCResume message. In other words, the UE uses the PDCCH-related configuration provided in System Information until successful reception of RRCResume message. The PDCCH-related configuration could comprise Control Resource Set (CORESET) configuration (e.g. controlResourceSetToAddModList, ControlResourceSet). The PDCCH-related configuration could comprise search space configuration (e.g. searchSpacesToAddModList, SearchSpace). The PDCCH-related configuration could comprise TCI states configuration for PDCCH (e.g. tci-StatesPDCCH-ToAddList).
For RACH based SDT procedure, it is assumed that during the RA procedure for SDT on a Cell, the UE monitors PDCCH (for receiving e.g. Msg2, Msg4, or MsgB [2]) based on the PDCCH-related configuration provided in System Information (e.g. MIB or SIB1) of the Cell. The PDCCH-related configuration used during the RA procedure for SDT could be the same as the PDCCH-related configuration used during the RA procedure not for SDT. The PDCCH-related configuration used during the RA procedure for SDT could be different from the PDCCH-related configuration used during the RA procedure not for SDT. For example, the CORESET configuration used during the RA procedure for SDT could be the same as the CORESET configuration used during the RA procedure not for SDT (e.g. controlResourceSetZero), while the search space configuration used during the RA procedure for SDT (e.g. other than ra-SearchSpace) could be different from the search space configuration used during the RA procedure not for SDT (e.g. ra-SearchSpace).
For example, the CORESET configuration used during the RA procedure for SDT (e.g. other than controlResourceSetZero) could be different from the CORESET configuration used during the RA procedure not for SDT (e.g. controlResourceSetZero), while the search space configuration used during the RA procedure for SDT could be the same as the search space configuration used during the RA procedure not for SDT (e.g. ra-SearchSpace). For example, both the CORESET configuration and the search space configuration used during the RA procedure for SDT could be the same as the CORESET configuration and the search space configuration used during the RA procedure not for SDT. For example, both the CORESET configuration and the search space configuration used during the RA procedure for SDT could be different from the CORESET configuration and the search space configuration used during the RA procedure not for SDT.
The network could indicate which PDCCH-related configuration among the PDCCH-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT. For example, the network provides a list of search space configurations in System Information, and an indication indicates that which search space among the list is to be used during the RA procedure for SDT. The indication could be provided in System Information (e.g. SIB1). The indication could be provided in a dedicated signaling (e.g. RRCRelease message) to the UE. Alternatively, the network directly provides a second search space configuration in System Information, wherein this second search space configuration is for RA procedures for SDT but not for RA procedures not for SDT.
In case there is subsequent transmission(s) in a RACH based SDT procedure, since the RA procedure will be considered as completed in response to successful reception of the first DL transmission (e.g. Msg4 or MsgB) of the SDT procedure, it is unclear which PDCCH-related configuration is used by the UE to monitor PDCCH during (the phase of) the subsequent transmission(s), e.g. to monitor PDCCH in order to receive scheduling (e.g. dynamic uplink grant or downlink assignment) for the subsequent transmission(s). An example is shown in
For the subsequent transmission(s) in a RACH based SDT procedure, the UE could monitor PDCCH based on at least one of the following alternatives:
1. The PDCCH-Related Configuration Used for the Subsequent Transmission(s) is the Same as the One Used During the RA Procedure for SDT
For example, the network provides a first CORESET configuration in System Information. The UE uses the first CORESET configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE also uses the first CORESET configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first and a second CORESET configuration in System Information. The UE uses the first CORESET configuration during RA procedures not for SDT, and the UE uses the second CORESET configuration during RA procedures for SDT, and the UE also uses the second CORESET configuration during the subsequent transmission(s) in a SDT procedure.
For example, the network provides a first search space configuration in System Information. The UE uses the first search space configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE also uses the first search space configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first and a second search space configuration in System Information. The UE uses the first search space configuration during RA procedures not for SDT, and the UE uses the second search space configuration during RA procedures for SDT, and the UE also uses the second search space configuration during the subsequent transmission(s) in a SDT procedure.
Since the PDCCH-related configuration used during the RA procedure for SDT is provided in System Information, there may be some restrictions for the network on scheduling the UE during the subsequent transmission(s). For example, since the search space #0 (i.e. SearchSpaceZero) provided in MIB is common search space, the network is not able to schedule the UE using Downlink Control Information (DCI) format 0_1 or DCI format 1_1 if the UE is monitoring PDCCH using this search space configuration.
The PDCCH-related configuration for the SDT procedure could be provided in SIB1. The PDCCH-related configuration for the SDT procedure could be provided in a System Information Block (other than SIB1), e.g. the SIB providing configurations related to SDT.
The network could provide an indication to indicate which PDCCH-related configuration among the PDCCH-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT. The indication could be ra-searchspace. The indication could be other than ra-searchspace.
2. The PDCCH-Related Configuration Used for the Subsequent Transmission(s) is Also Provided in System Information (e.g. MIB or SIB1) but could be Different from the PDCCH-Related Configuration Used During the RA Procedure for SDT
For example, the network provides a first and a second CORESET configuration in System Information. The UE uses the first CORESET configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE uses the second CORESET configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first, a second, and a third CORESET configuration in System Information. The UE uses the first CORESET configuration during RA procedures not for SDT, and the UE uses the second CORESET configuration during RA procedures for SDT, and the UE also uses the third CORESET configuration during the subsequent transmission(s) in a SDT procedure.
For example, the network provides a first and a second search space configuration in System Information. The UE uses the first search space configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE uses the second search space configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first, a second, and a third search space configuration in System Information. The UE uses the first search space configuration during RA procedures not for SDT, and the UE uses the second search space configuration during RA procedures for SDT, and the UE also uses the third search space configuration during the subsequent transmission(s) in a SDT procedure.
Since the PDCCH-related configuration used for the subsequent transmission(s) is provided in System Information, there may be some restrictions for the network on scheduling the UE during the subsequent transmission(s). The search space used for the subsequent transmission(s) could be a common search space. For example, since the list of search spaces (i.e. commonSearchSpaceList) provided in SIB1 are common search spaces, the network is not able to schedule the UE using DCI format 0_1 or DCI format 1_1 if the UE is monitoring PDCCH using a search space among this list.
The PDCCH-related configuration for the SDT procedure (e.g. used for the subsequent transmission(s)) could be provided in SIB 1. The PDCCH-related configuration for the SDT procedure could be provided in a System Information Block (other than SIB1), e.g. the SIB providing configurations related to SDT.
The network could provide a first indication to indicate which PDCCH-related configuration among the PDCCH-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT. The first indication could be ra-searchspace. The first indication could be other than ra-searchspace. The network could provide a second indication to indicate which PDCCH-related configuration among the PDCCH-related configuration(s) provided in System Information is to be used by the UE for the subsequent transmission(s). The second indication could be different from the first indication.
3. The PDCCH-Related Configuration Used for the Subsequent Transmission(s) is Provided in the First DL Transmission (e.g. Msg4 or MsgB) of the SDT Procedure
The network could directly provide the PDCCH-related configuration in the first DL transmission of the SDT procedure to the UE. In response to receiving the PDCCH-related configuration in the first DL transmission of the SDT procedure, the UE could monitor PDCCH during the subsequent transmission(s) in the SDT procedure, based on the received PDCCH-related configuration.
For example, the network provides a first CORESET configuration in System Information and the network provides a second CORESET configuration in the first DL transmission of a SDT procedure. The UE uses the first CORESET configuration during RA procedures for SDT, and the UE uses the second CORESET configuration during the subsequent transmission(s) in the SDT procedure. For example, the network provides a first search space configuration in System Information and the network provides a second search space configuration in the first DL transmission of a SDT procedure. The UE uses the first search space configuration during RA procedures for SDT, and the UE uses the second search space configuration during the subsequent transmission(s) in the SDT procedure.
For example, the network provides Transport Configuration Indicator (TCI) states configuration for PDCCH in the first DL transmission of a SDT procedure. The UE uses the TCI states configuration for PDCCH during the subsequent transmission(s) in the SDT procedure.
The PDCCH-related configuration provided in a first SDT procedure could be used for a second SDT procedure initiated after the first SDT procedure has been completed. For example, while the UE is in RRC_INACTIVE state, the network could transmit a RRCRelease message with suspendConfig to complete a first SDT procedure initiated by the UE. The network could provide the PDCCH-related configuration in the RRCRelease message, so that later when the UE initiates a second SDT procedure, the UE could use the previously provided PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the second SDT procedure.
The PDCCH-related configuration in the first DL transmission could be included in a RRC message (e.g. RRCRelease message).
Because the PDCCH-related configuration is provided in a dedicated signaling (e.g. RRCRelease message) to a UE, the network could provide the configuration which is suitable for scheduling the subsequent transmission(s) for this UE. For example, the network could provide a search space configuration which is UE-specific search space, and thus the network is able to schedule the UE with DCI format 0_1 or DCI format 1_1. For example, the network could provide the TCI states configuration for PDCCH, and the network could indicate, with a TCI state indication for PDCCH MAC control element, the TCI state used for monitoring PCCCH.
4. The PDCCH-Related Configuration Used for the Subsequent Transmission(s) is the One which was Used by the UE in Previous RRC_CONNECTED State
Upon entering RRC_INACTIVE state from RRC_CONNECTED state, the UE will store (part of) its current RRC configuration in the UE Inactive AS context. The UE Inactive AS context also contains the PDCCH-related configuration. The UE could restore the PDCCH-related configuration from the UE Inactive AS context, for monitoring PDCCH during the subsequent transmission(s).
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the CORESET configuration from the UE Inactive AS context, and uses the restored CORESET configuration for monitoring PDCCH during the subsequent transmission(s). For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the search space configuration from the UE Inactive AS context, and uses the restored search space configuration for monitoring PDCCH during the subsequent transmission(s).
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the TCI states configuration for PDCCH from the UE Inactive AS context, and uses the restored TCI states configuration for PDCCH for monitoring PDCCH during the subsequent transmission(s).
Because the stored PDCCH-related configuration is dedicated configuration of a UE, it may be more suitable for scheduling the subsequent transmission(s) for this UE. For example, the stored PDCCH-related configuration contains a search space which is UE-specific search space, and thus the network is able to schedule the UE with DCI format 0_1 or DCI format 1_1. For example, the stored PDCCH-related configuration contains the TCI states configuration for PDCCH, and the network could indicate, with a TCI state indication for PDCCH MAC control element, the TCI state used for monitoring PDCCH.
The UE could restore the PDCCH-related configuration of its SpCell (e.g. the PCell in previous RRC connection). In case there is multiple DL BWPs (under the SpCell) in the UE Inactive AS context, the UE could restore the PDCCH-related configuration under the initial DL BWP. Additionally or alternatively, the network could indicate (e.g. in Msg4 or MsgB) which DL BWP among the multiple DL BWPs the UE restores the PDCCH-related configuration. For example, if the network does not indicate which DL BWP among the multiple DL BWPs the UE restores the PDCCH-related configuration, the UE restores the PDCCH-related configuration under the initial DL BWP. For example, if the network indicates (e.g. in Msg4 or MsgB) which DL BWP among the multiple DL BWPs the UE restores the PDCCH-related configuration, the UE restores the PDCCH-related configuration under the DL BWP indicated by the network.
5. The PDCCH-Related Configuration Used for the Subsequent Transmission(s) is Provided in the RRCRelease Message which Transits the UE from RRC_CONNECTED State to RRC_INACTIVE State
Before the UE enters RRC_INACTIVE state, the network could provide the PDCCH-related configuration to be used for the subsequent transmission(s) in a SDT procedure initiated by the UE later. In response to receiving the PDCCH-related configuration in the RRCRelease message received in RRC_CONNECTED state triggering state transition, the UE could store the received PDCCH-related configuration in the UE Inactive AS context. The received PDCCH-related configuration could be different from the PDCCH-related configuration(s) which was used by the UE in RRC_CONNECTED state. In other words, the UE could store (at least) two PDCCH-related configurations in the UE Inactive AS context, wherein one is used while the UE is in RRC_CONNECTED state, and the other one is received in the RRCRelease message triggering state transition to RRC_INACTIVE. In response to initiation of a SDT procedure or in response to receiving an indication from the network indicating that there is subsequent transmission(s) in the SDT procedure, the UE could restore the PDCCH-related configuration (to be used for the subsequent transmission(s)) from the UE Inactive AS context.
For example, while the UE is in RRC_CONNECTED state, the network transmits a RRCRelease message with suspendConfig to transit the UE into RRC_INACTIVE state. The network could provide the PDCCH-related configuration (to be used for the subsequent transmission(s)) in the RRCRelease message, so that later when the UE initiates a SDT procedure, the UE could use the previously provided PDCCH-related configuration received in the RRCRelease message for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure.
Because the stored PDCCH-related configuration is dedicated configuration of a UE, it may be more suitable for scheduling the subsequent transmission(s) for this UE. For example, the stored PDCCH-related configuration contains a search space which is UE-specific search space, and thus the network is able to schedule the UE with DCI format 0_1 or DCI format 1_1. For example, the stored PDCCH-related configuration contains the TCI states configuration for PDCCH, and the network could indicate, with a TCI state indication for PDCCH MAC control element, the TCI state used for monitoring PDCCH.
Combinations of the above alternatives are possible.
For a first example, if the network provides PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network does not provide PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the PDCCH-related configuration provided in System Information for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1 or alternative 2). An example is shown in
For a second example, if the network provides PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network does not provide PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE restores the PDCCH-related configuration from the UE Inactive AS context, for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 4).
For a third example, if the network provides (or indicates) a second PDCCH-related configuration in System Information to be used for the subsequent transmission(s), the UE uses the second PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2). If the network does not provide (or indicate) a second PDCCH-related configuration in System Information to be used for the subsequent transmission(s), the UE continues using the same PDCCH-related configuration used during the RA procedure for SDT, for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1). An example is shown in
For a fourth example, if the network provides a first PDCCH-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network does not provide a second PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided first PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3). If the network provides a first PDCCH-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network also provides a second PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided second PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3).
For a fifth example, if the network provides a first PDCCH-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network does not provide a second PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided first PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 5). If the network provides a first PDCCH-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network also provides a second PDCCH-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided second PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3).
For a sixth example, if the network provides (or indicates) a first PDCCH-related configuration in System Information to be used for the subsequent transmission(s), and the network does not provide a second PDCCH-related configuration in the RRCRelease message transmitted before the UE initiates a SDT procedure, the UE uses the first PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2). If the network provides (or indicates) a first PDCCH-related configuration in System Information to be used for the subsequent transmission(s), and the network also provides a second PDCCH-related configuration in the RRCRelease message transmitted before the UE initiates a SDT procedure, the UE uses the second PDCCH-related configuration for monitoring PDCCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3 or alternative 5).
During the RRC Resume procedure (e.g. a RA procedure) on a Cell, the UE performs transmission on Physical Uplink Shared Channel (PUSCH) and/or reception on Physical Downlink Shared Channel (PDSCH) based on the Shared-channel-related configuration provided in System Information (e.g. SIB1) of the Cell. In response to successful reception of RRCResume message, the UE may restore the Shared-channel-related configuration from its stored UE Inactive AS context, and the network may also provide Shared-channel-related configuration in the RRCResume message. In other words, the UE uses the Shared-channel-related configuration provided in System Information until successful reception of RRCResume message. The Shared-channel-related configuration could comprise PUSCH configuration (e.g. PUSCH-Config). The Shared-channel-related configuration could comprise PDSCH configuration (e.g PDSCH-Config). The Shared-channel-related configuration could comprise TCI states configuration for PDSCH (e.g. tci-StatesToAddModList). The Shared-channel-related configuration could comprise configured grant configuration (e.g. ConfiguredGrantConfig). The Shared-channel-related configuration could comprise semi-persistent scheduling configuration (e.g. SPS-Config).
For RACH based SDT procedure, it is assumed that during the RA procedure for SDT on a Cell, the UE performs transmission on PUSCH and/or reception on PDSCH based on the Shared-channel-related configuration also provided in System Information (e.g. SIB1) of the Cell. The Shared-channel-related configuration used during the RA procedure for SDT could be the same as the Shared-channel-related configuration used during the RA procedure not for SDT. The Shared-channel-related configuration used during the RA procedure for SDT could be different from the Shared-channel-related configuration used during the RA procedure not for SDT.
For example, the PDSCH configuration used during the RA procedure for SDT could be the same as the PDSCH configuration used during the RA procedure not for SDT (e.g. PDSCH-Config), while the PUSCH configuration used during the RA procedure for SDT (e.g. other than PUSCH-Config) could be different from the PUSCH configuration used during the RA procedure not for SDT (e.g. PUSCH-Config). For example, the PDSCH configuration used during the RA procedure for SDT (e.g. other than PDSCH-Config) could be different from the PDSCH configuration used during the RA procedure not for SDT (e.g. PDSCH-Config), while the PUSCH configuration used during the RA procedure for SDT could be the same as the PUSCH configuration used during the RA procedure not for SDT (e.g. PUSCH-Config).
For example, both the PDSCH configuration and the PUSCH configuration used during the RA procedure for SDT could be the same as the PDSCH configuration and the PUSCH configuration used during the RA procedure not for SDT. For example, both the PDSCH configuration and the PUSCH configuration used during the RA procedure for SDT could be different from the PDSCH configuration and the PUSCH configuration used during the RA procedure not for SDT.
The network could indicate which Shared-channel-related configuration among the Shared-channel-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT. For example, the network provides a list of PDSCH configurations in System Information, and an indication indicates that which PDSCH among the list is to be used during the RA procedure for SDT. The indication could be provided in System Information (e.g. SIB1). The indication could be provided in a dedicated signaling (e.g. RRCRelease message) to the UE. Alternatively, the network directly provides a second PDSCH configuration in System Information, wherein this second PDSCH configuration is for RA procedures for SDT but not for RA procedures not for SDT.
In case there is subsequent transmission(s) in a RACH based SDT procedure, since the RA procedure will be considered as completed in response to successful reception of the first DL transmission (e.g. Msg4 or MsgB) of the SDT procedure, it is unclear which Shared-channel-related configuration is used by the UE to perform transmission on PUSCH and/or reception on PDSCH during (the phase of) the subsequent transmission(s).
For the subsequent transmission(s) in a RACH based SDT procedure, the UE could perform transmission on PUSCH and/or reception on PDSCH based on at least one of the following alternatives:
1. The Shared-Channel-Related Configuration Used for the Subsequent Transmission(s) is the Same as the One Used During the RA Procedure for SDT
For example, the network provides a first PDSCH configuration in System Information. The UE uses the first PDSCH configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE also uses the first PDSCH configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first and a second PDSCH configuration in System Information. The UE uses the first PDSCH configuration during RA procedures not for SDT, and the UE uses the second PDSCH configuration during RA procedures for SDT, and the UE also uses the second PDSCH configuration during the subsequent transmission(s) in a SDT procedure.
For example, the network provides a first PUSCH configuration in System Information. The UE uses the first PUSCH configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE also uses the first PUSCH configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first and a second PUSCH configuration in System Information. The UE uses the first PUSCH configuration during RA procedures not for SDT, and the UE uses the second PUSCH configuration during RA procedures for SDT, and the UE also uses the second PUSCH configuration during the subsequent transmission(s) in a SDT procedure.
Since the Shared-channel-related configuration used during the RA procedure for SDT is provided in System Information, there may be some restrictions for the network on scheduling the UE during the subsequent transmission(s).
The Shared-channel-related configuration for the SDT procedure could be provided in SIB1. The Shared-channel-related configuration for the SDT procedure could be provided in a System Information Block (other than SIB1), e.g. the SIB providing configurations related to SDT.
The network could provide an indication to indicate which Shared-channel-related configuration among the Shared-channel-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT.
2. The Shared-Channel-Related Configuration Used for the Subsequent Transmission(s) is Also Provided in System Information but could be Different from the Shared-Channel-Related Configuration Used During the RA Procedure for SDT
For example, the network provides a first and a second PDSCH configuration in System Information. The UE uses the first PDSCH configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE uses the second PDSCH configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first, a second, and a third PDSCH configuration in System Information. The UE uses the first PDSCH configuration during RA procedures not for SDT, and the UE uses the second PDSCH configuration during RA procedures for SDT, and the UE also uses the third PDSCH configuration during the subsequent transmission(s) in a SDT procedure.
For example, the network provides a first and a second PUSCH configuration in System Information. The UE uses the first PUSCH configuration during RA procedures not for SDT as well as during RA procedures for SDT, and the UE uses the second PUSCH configuration during the subsequent transmission(s) in a SDT procedure. For example, the network provides a first, a second, and a third PUSCH configuration in System Information. The UE uses the first PUSCH configuration during RA procedures not for SDT, and the UE uses the second PUSCH configuration during RA procedures for SDT, and the UE also uses the third PUSCH configuration during the subsequent transmission(s) in a SDT procedure.
Since the Shared-channel-related configuration used for the subsequent transmission(s) is provided in System Information, there may be some restrictions for the network on scheduling the UE during the subsequent transmission(s).
The Shared-channel-related configuration for the SDT procedure could be provided in SIB1. The Shared-channel-related configuration for the SDT procedure could be provided in a System Information Block (other than SIB1), e.g. the SIB providing configurations related to SDT.
The network could provide a first indication to indicate which Shared-channel-related configuration among the Shared-channel-related configuration(s) provided in System Information is to be used by the UE during the RA procedure for SDT. The network could provide a second indication to indicate which Shared-channel-related configuration among the Shared-channel-related configuration(s) provided in System Information is to be used by the UE for the subsequent transmission(s). The second indication could be different from the first indication.
3. The Shared-Channel-Related Configuration Used for the Subsequent Transmission(s) is Provided in the First DL Transmission (e.g. Msg4 or MsgB) of the SDT Procedure
The network could directly provide the Shared-channel-related configuration in the first DL transmission of the SDT procedure to the UE. In response to receiving the Shared-channel-related configuration in the first DL transmission of the SDT procedure, the UE could perform transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure, based on the received Shared-channel-related configuration.
For example, the network provides a first PDSCH configuration in System Information and the network provides a second PDSCH configuration in the first DL transmission of a SDT procedure. The UE uses the first PDSCH configuration during RA procedures for SDT, and the UE uses the second PDSCH configuration during the subsequent transmission(s) in the SDT procedure. For example, the network provides a first PUSCH configuration in System Information and the network provides a second PUSCH configuration in the first DL transmission of a SDT procedure. The UE uses the first PUSCH configuration during RA procedures for SDT, and the UE uses the second PUSCH configuration during the subsequent transmission(s) in the SDT procedure.
For example, the network provides TCI states configuration for PDSCH in the first DL transmission of a SDT procedure. The UE uses the TCI states configuration for PDSCH during the subsequent transmission(s) in the SDT procedure.
The Shared-channel-related configuration provided in a first SDT procedure could be used for a second SDT procedure initiated after the first SDT procedure has been completed. For example, while the UE is in RRC_INACTIVE state, the network could transmit a RRCRelease message with suspendConfig to complete a first SDT procedure initiated by the UE. The network could provide the Shared-channel-related configuration in the RRCRelease message, so that later when the UE initiates a second SDT procedure, the UE could use the previously provided Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the second SDT procedure.
The Shared-channel-related configuration in the first DL transmission could be included in a RRC message (e.g. RRCRelease message).
Because the Shared-channel-related configuration is provided in a dedicated signaling (e.g. RRCRelease message) to a UE, the network could provide the configuration which is suitable for scheduling the subsequent transmission(s) for this UE. For example, the network could provide the TCI states configuration for PDSCH, and the network could indicate, with DCI format 1_1, the TCI state used for receiving PDSCH.
4. The Shared-Channel-Related Configuration Used for the Subsequent Transmission(s) is the One which was Used by the UE in Previous RRC_CONNECTED State
Upon entering RRC_INACTIVE state from RRC_CONNECTED state, the UE will store (part of) its current RRC configuration in the UE Inactive AS context. The UE Inactive AS context also contains the Shared-channel-related configuration. The UE could restore the Shared-channel-related configuration from the UE Inactive AS context, for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s).
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the PDSCH configuration from the UE Inactive AS context, and use the restored PDSCH configuration for performing reception on PDSCH during the subsequent transmission(s). For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the PUSCH configuration from the UE Inactive AS context, and use the restored PUSCH configuration for performing transmission on PUSCH during the subsequent transmission(s).
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the TCI states configuration for PDSCH from the UE Inactive AS context, and use the restored TCI states configuration for PDSCH for performing reception on PDSCH during the subsequent transmission(s).
Because the stored Shared-channel-related configuration is dedicated configuration of a UE, it may be more suitable for scheduling the subsequent transmission(s) for this UE. For example, the stored Shared-channel-related configuration contains the TCI states configuration for PDSCH, and the network could indicate, with DCI format 1_1, the TCI state used for receiving PDSCH.
The UE could restore the Shared-channel-related configuration of its SpCell (e.g. the PCell in previous RRC connection). In case there is multiple DL BWPs (under the SpCell) in the UE Inactive AS context, the UE could restore the Shared-channel-related configuration under the initial DL BWP. Additionally or alternatively, the network could indicate (e.g. in Msg4 or MsgB) which DL BWP among the multiple DL BWPs the UE restores the Shared-channel-related configuration.
For example, if the network does not indicate which DL BWP among the multiple DL BWPs the UE restores the Shared-channel-related configuration, the UE restores the Shared-channel-related configuration under the initial DL BWP. For example, if the network indicates (e.g. in Msg4 or MsgB) which DL BWP among the multiple DL BWPs the UE restores the Shared-channel-related configuration, the UE restores the Shared-channel-related configuration under the DL BWP indicated by the network. In case there is multiple UL BWPs (under the SpCell) in the UE Inactive AS context, the UE could restore the Shared-channel-related configuration under the initial UL BWP.
Additionally or alternatively, the network could indicate (e.g. in Msg4 or MsgB) which UL BWP among the multiple UL BWPs the UE restores the Shared-channel-related configuration. For example, if the network does not indicate which UL BWP among the multiple UL BWPs the UE restores the Shared-channel-related configuration, the UE restores the Shared-channel-related configuration under the initial UL BWP. For example, if the network indicates (e.g. in Msg4 or MsgB) which UL BWP among the multiple UL BWPs the UE restores the Shared-channel-related configuration, the UE restores the Shared-channel-related configuration under the UL BWP indicated by the network.
5. The Shared-Channel-Related Configuration Used for the Subsequent Transmission(s) is Provided in the RRCRelease Message which Transits the UE from RRC_CONNECTED State to RRC_INACTIVE State
Before the UE enters RRC_INACTIVE state, the network could provide the Shared-channel-related configuration to be used for the subsequent transmission(s) in a SDT procedure initiated by the UE later. In response to receiving the Shared-channel-related configuration in the RRCRelease message received in RRC_CONNECTED state triggering state transition, the UE could store the received Shared-channel-related configuration in the UE Inactive AS context. The received Shared-channel-related configuration could be different from the Shared-channel-related configuration(s) which was used by the UE in RRC_CONNECTED state. In other words, the UE could store (at least) two Shared-channel-related configurations in the UE Inactive AS context, wherein one is used while the UE is in RRC_CONNECTED state, and the other one is received in the RRCRelease message triggering state transition to RRC_INACTIVE. In response to initiation of a SDT procedure or in response to receiving an indication from the network indicating that there is subsequent transmission(s) in the SDT procedure, the UE could restore the Shared-channel-related configuration (to be used for the subsequent transmission(s)) from the UE Inactive AS context.
For example, while the UE is in RRC_CONNECTED state, the network transmits a RRCRelease message with suspendConfig to transit the UE into RRC_INACTIVE state. The network could provide the Shared-channel-related configuration (to be used for the subsequent transmission(s)) in the RRCRelease message, so that later when the UE initiates a SDT procedure, the UE could use the previously provided Shared-channel-related configuration received in the RRCRelease message for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure.
Because the stored Shared-channel-related configuration is dedicated configuration of a UE, it may be more suitable for scheduling the subsequent transmission(s) for this UE. For example, the stored Shared-channel-related configuration contains the TCI states configuration for PDSCH, and the network could indicate, with DCI format 1_1, the TCI state used for receiving PDSCH.
Combinations of the above alternatives are possible.
For a first example, if the network provides Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network does not provide Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the Shared-channel-related configuration provided in System Information for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1 or alternative 2).
For a second example, if the network provides Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network does not provide Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE restores the Shared-channel-related configuration from the UE Inactive AS context, for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 4).
For a third example, if the network provides (or indicates) a second Shared-channel-related configuration in System Information to be used for the subsequent transmission(s), the UE uses the second Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2). If the network does not provide (or indicate) a second Shared-channel-related configuration in System Information to be used for the subsequent transmission(s), the UE continues using the same Shared-channel-related configuration used during the RA procedure for SDT, for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1).
For a fourth example, if the network provides a first Shared-channel-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network does not provide a second Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided first Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3). If the network provides a first Shared-channel-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network also provides a second Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided second Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3).
For a fifth example, if the network provides a first Shared-channel-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network does not provide a second Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided first Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 5). If the network provides a first Shared-channel-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network also provides a second Shared-channel-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided second Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3).
For a sixth example, if the network provides (or indicates) a first Shared-channel-related configuration in System Information to be used for the subsequent transmission(s), and the network does not provide a second Shared-channel-related configuration in the RRCRelease message transmitted before the UE initiates a SDT procedure, the UE uses the first Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2). If the network provides (or indicates) a first Shared-channel-related configuration in System Information to be used for the subsequent transmission(s), and the network also provides a second Shared-channel-related configuration in the RRCRelease message transmitted before the UE initiates a SDT procedure, the UE uses the second Shared-channel-related configuration for performing transmission on PUSCH and/or reception on PDSCH during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3 or alternative 5).
During the RRC Resume procedure (e.g. a RA procedure) on a Cell, each time before performing the Msg1/MsgA transmission, the UE selects a beam (or SSB). The UE uses the selected beam for transmission and/or reception until e.g. successful completion of the RA procedure. In case there is subsequent transmission(s) in a RACH based SDT procedure, the network may decide to change the beam (or the TCI state) used by the UE for performing transmission and/or reception during the subsequent transmission(s). Some assistance information may be required for the network to determine which beam (or the TCI state) is to be used by the UE. For example, the UE may be requested to perform CSI measurement and/or CSI reporting, so that the network could choose a better beam (or the TCI state) to be used for the UE when needed.
For example, the UE could perform Channel State Information (CSI) measurement during the RA procedure for SDT. For example, the UE could perform CSI measurement during the subsequent transmission(s) in the SDT procedure. For example, the UE could perform CSI reporting during the RA procedure for SDT. For example, the UE could perform CSI reporting during the subsequent transmission(s) in the SDT procedure. The CSI reporting could be periodic. The CSI reporting could be aperiodic (e.g. triggered using CSI request in DCI format 0_1). The CSI reporting could be semi-persistent.
Since the UE is not able to perform CSI measurement and/or CSI reporting without corresponding configuration (referred to as “CSI-measurement/reporting-related configuration”), how the UE acquires the CSI-measurement/reporting-related configuration to be used in SDT needs to be specified. The CSI-measurement/reporting-related configuration could comprise CSI measurement configuration (e.g. CSI-MeasConfig). The CSI-measurement/reporting-related configuration could comprise CSI reporting configuration (e.g. CSI-ReportConfig). The CSI-measurement/reporting-related configuration could comprise Physical Uplink Control Channel (PUCCH) configuration (e.g. PUCCH-Config).
For the RACH based SDT procedure, the UE could performing CSI measurement and/or CSI reporting (during the SDT procedure) based on at least one of the following alternatives:
1. The CSI-Measurement/Reporting-Related Configuration Used for the RACH Based SDT Procedure is Provided in the First DL Transmission (e.g. Msg4 or MsgB) of the SDT Procedure
The network could directly provide the CSI-measurement/reporting-related configuration in the first DL transmission of the SDT procedure to the UE. In response to receiving the CSI-measurement/reporting-related configuration in the first DL transmission of the SDT procedure, the UE could performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the SDT procedure, based on the received CSI-measurement/reporting-related configuration.
For example, the network provides a CSI measurement configuration in the first DL transmission of a SDT procedure. The UE uses the CSI measurement configuration for performing CSI measurement during the subsequent transmission(s) in the SDT procedure. For example, the network provides a CSI reporting configuration in the first DL transmission of a SDT procedure. The UE uses the CSI reporting configuration for performing CSI reporting during the subsequent transmission(s) in the SDT procedure.
The CSI-measurement/reporting-related configuration provided in a first SDT procedure could be used for a second SDT procedure initiated after the first SDT procedure has been completed. For example, while the UE is in RRC_INACTIVE state, the network could transmit a RRCRelease message with suspendConfig to complete a first SDT procedure initiated by the UE. The network could provide the CSI-measurement/reporting-related configuration in the RRCRelease message, so that later when the UE initiates a second SDT procedure, the UE could use the previously provided CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the second SDT procedure and/or during the RA procedure for the second SDT procedure.
The CSI-measurement/reporting-related configuration in the first DL transmission could be included in a RRC message (e.g. RRCRelease message).
2. The CSI-Measurement/Reporting-Related Configuration Used for the RACH Based SDT Procedure is the One which was Used by the UE in Previous RRC_CONNECTED State
Upon entering RRC_INACTIVE state from RRC_CONNECTED state, the UE will store (part of) its current RRC configuration in the UE Inactive AS context. The UE Inactive AS context also contains the CSI-measurement/reporting-related configuration. The UE could restore the CSI-measurement/reporting-related configuration from the UE Inactive AS context, for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in a SDT procedure and/or during the RA procedure for the SDT procedure.
For example, in response to initiating a SDT procedure, the UE restores the CSI measurement configuration from the UE Inactive AS context, and use the restored CSI measurement configuration for performing CSI measurement during the RA procedure for the SDT procedure and/or during the subsequent transmission(s) in the SDT procedure. For example, in response to initiating a SDT procedure, the UE restores the CSI reporting configuration from the UE Inactive AS context, and use the restored CSI reporting configuration for performing CSI reporting during the RA procedure for the SDT procedure and/or during the subsequent transmission(s) in the SDT procedure.
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the CSI measurement configuration from the UE Inactive AS context, and use the restored CSI measurement configuration for performing CSI measurement during the subsequent transmission(s). For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the CSI reporting configuration from the UE Inactive AS context, and use the restored CSI reporting configuration for performing CSI reporting during the subsequent transmission(s).
The UE could restore the CSI-measurement/reporting-related configuration of its SpCell (e.g. the PCell in previous RRC connection).
3. The CSI-Measurement/Reporting-Related Configuration Used for the RACH Based SDT Procedure is Provided in the RRCRelease Message which Transits the UE from RRC_CONNECTED State to RRC_INACTIVE State
Before the UE enters RRC_INACTIVE state, the network could provide the CSI-measurement/reporting-related configuration to be used for the RACH based SDT procedure initiated by the UE later. In response to receiving the CSI-measurement/reporting-related configuration in the RRCRelease message received in RRC_CONNECTED state triggering state transition, the UE could store the received CSI-measurement/reporting-related configuration in the UE Inactive AS context. The received CSI-measurement/reporting-related configuration could be different from the CSI-measurement/reporting-related configuration(s) which was used by the UE in RRC_CONNECTED state. In other words, the UE could store (at least) two CSI-measurement/reporting-related configurations in the UE Inactive AS context, wherein one is used while the UE is in RRC_CONNECTED state, and the other one is received in the RRCRelease message triggering state transition to RRC_INACTIVE. In response to initiation of a SDT procedure or in response to receiving an indication from the network indicating that there is subsequent transmission(s) in the SDT procedure, the UE could restore the CSI-measurement/reporting-related configuration (to be used for the RACH based SDT procedure) from the UE Inactive AS context.
For example, while the UE is in RRC_CONNECTED state, the network transmits a RRCRelease message with suspendConfig to transit the UE into RRC_INACTIVE state. The network could provide the CSI-measurement/reporting-related configuration (to be used for the RACH based SDT procedure) in the RRCRelease message, so that later when the UE initiates a SDT procedure, the UE could use the previously provided CSI-measurement/reporting-related configuration received in the RRCRelease message for performing CSI measurement and/or CSI reporting during the RA procedure for the SDT procedure and/or during the subsequent transmission(s) in the SDT procedure.
Combinations of the above alternatives are possible.
For a first example, if the network provides CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1). If the network does not provide CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE restores the CSI-measurement/reporting-related configuration from the UE Inactive AS context, for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2).
For a second example, if the network provides a first CSI-measurement/reporting-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network does not provide a second CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided first CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 1). If the network provides a first CSI-measurement/reporting-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network also provides a second CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided second CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 1).
For a third example, if the network provides a first CSI-measurement/reporting-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network does not provide a second CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided first CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network provides a first CSI-measurement/reporting-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network also provides a second CSI-measurement/reporting-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided second CSI-measurement/reporting-related configuration for performing CSI measurement and/or CSI reporting during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1).
During the RRC Resume procedure (e.g. a RA procedure) on a Cell, each time before performing the Msg1/MsgA transmission, the UE selects a beam (or SSB). The UE uses the selected beam for transmission and/or reception until (e.g. successful completion of the RA procedure). From the network's perspective, after the network successfully detects and receives UL transmissions from the UE, the network may use a beam for following transmissions and/or receptions to/from the UE during the RA procedure.
In case there is subsequent transmission(s) in a RACH based SDT procedure, the network may decide to change the beam used by the network for performing transmission (to the UE) and/or reception (from the UE) during the subsequent transmission(s). Some assistance information may be required for the network to determine which beam is to be used by the network. For example, the UE may be requested to perform Sounding Reference Signal (SRS) transmissions, so that the network could choose a better beam to use when needed. The SRS transmissions could be periodic. The SRS transmissions could be aperiodic (e.g. triggered using SRS request in DCI format 0_1 or DCI format 1_1). The SRS transmissions could be semi-persistent.
Since the UE is not able to perform SRS transmissions without corresponding configuration (referred to as “SRS-related configuration”), how the UE acquires the SRS-related configuration to be used in SDT needs to be specified. The SRS-related configuration could comprise SRS configuration (e.g. SRS-Config).
For the RACH based SDT procedure, the UE could perform SRS transmissions (during the SDT procedure) based on at least one of the following alternatives:
1. The SRS-Related Configuration Used for the RACH Based SDT Procedure is Provided in the First DL Transmission (e.g. Msg4 or MsgB) of the SDT Procedure
The network could directly provide the SRS-related configuration in the first DL transmission of the SDT procedure to the UE. In response to receiving the SRS-related configuration in the first DL transmission of the SDT procedure, the UE could perform SRS transmissions during the subsequent transmission(s) in the SDT procedure, based on the received SRS-related configuration.
For example, the network provides a SRS configuration in the first DL transmission of a SDT procedure. The UE uses the SRS configuration for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure.
The SRS-related configuration provided in a first SDT procedure could be used for a second SDT procedure initiated after the first SDT procedure has been completed. For example, while the UE is in RRC_INACTIVE state, the network could transmit a RRCRelease message with suspendConfig to complete a first SDT procedure initiated by the UE. The network could provide the SRS-related configuration in the RRCRelease message, so that later when the UE initiates a second SDT procedure, the UE could use the previously provided SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the second SDT procedure.
The SRS-related configuration in the first DL transmission could be included in a RRC message (e.g. RRCRelease message).
2. The SRS-Related Configuration Used for the RACH Based SDT Procedure is the One which was Used by the UE in Previous RRC_CONNECTED State
Upon entering RRC_INACTIVE state from RRC_CONNECTED state, the UE will store (part of) its current RRC configuration in the UE Inactive AS context. The UE Inactive AS context also contains the SRS-related configuration. The UE could restore the SRS-related configuration from the UE Inactive AS context, for performing SRS transmissions during the subsequent transmission(s).
For example, in response to receiving an indication from the network indicating that there is subsequent transmission(s) in a SDT procedure, the UE restores the SRS configuration from the UE Inactive AS context, and use the restored SRS configuration for performing SRS transmissions during the subsequent transmission(s).
The UE could restore the SRS-related configuration of its SpCell (e.g. the PCell in previous RRC connection). In case there is multiple UL BWPs (under the SpCell) in the UE Inactive AS context, the UE could restore the SRS-related configuration under the initial UL BWP. Additionally or alternatively, the network could indicate (e.g. in Msg4 or MsgB) which UL BWP among the multiple UL BWPs the UE restores the SRS-related configuration. For example, if the network does not indicate which UL BWP among the multiple UL BWPs the UE restores the SRS-related configuration, the UE restores the SRS-related configuration under the initial UL BWP. If the network indicates (e.g. in Msg4 or MsgB) which UL BWP among the multiple UL BWPs the UE restores the SRS-related configuration, the UE restores the SRS-related configuration under the UL BWP indicated by the network.
3. The SRS-Related Configuration Used for the RACH Based SDT Procedure is Provided in the RRCRelease Message which Transits the UE from RRC_CONNECTED State to RRC_INACTIVE State
Before the UE enters RRC_INACTIVE state, the network could provide the SRS-related configuration to be used for the subsequent transmission(s) in a SDT procedure initiated by the UE later. In response to receiving the SRS-related configuration in the RRCRelease message received in RRC_CONNECTED state triggering state transition, the UE could store the received SRS-related configuration in the UE Inactive AS context. The received SRS-related configuration could be different from the SRS-related configuration(s) which was used by the UE in RRC_CONNECTED state. In other words, the UE could store (at least) two SRS-related configurations in the UE Inactive AS context, wherein one is used while the UE is in RRC_CONNECTED state, and the other one is received in the RRCRelease message triggering state transition to RRC_INACTIVE. In response to initiation of a SDT procedure or in response to receiving an indication from the network indicating that there is subsequent transmission(s) in the SDT procedure, the UE could restore the SRS-related configuration (to be used for the subsequent transmission(s)) from the UE Inactive AS context.
For example, while the UE is in RRC_CONNECTED state, the network transmits a RRCRelease message with suspendConfig to transit the UE into RRC_INACTIVE state. The network could provide the SRS-related configuration (to be used for the subsequent transmission(s)) in the RRCRelease message, so that later when the UE initiates a SDT procedure, the UE could use the previously provided SRS-related configuration received in the RRCRelease message for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure.
Combinations of the above alternatives are possible.
For a first example, if the network provides SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1). If the network does not provide SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE restores the SRS-related configuration from the UE Inactive AS context, for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure (e.g. alternative 2).
For a second example, if the network provides a first SRS-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network does not provide a second SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided first SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3). If the network provides a first SRS-related configuration in the RRCRelease message transmitted in a first SDT procedure and the network also provides a second SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a second SDT procedure initiated by the UE after the first SDT procedure has been completed, the UE uses the provided second SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the second SDT procedure (e.g. alternative 3).
For a third example, if the network provides a first SRS-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network does not provide a second SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided first SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure (e.g. alternative 3). If the network provides a first SRS-related configuration in the RRCRelease message which transits the UE from RRC_CONNECTED state to RRC_INACTIVE state and the network also provides a second SRS-related configuration in the first DL transmission (e.g. Msg4 or MsgB) of a SDT procedure, the UE uses the provided second SRS-related configuration for performing SRS transmissions during the subsequent transmission(s) in the SDT procedure (e.g. alternative 1).
The subsequent transmission(s) as described in above alternatives could be a time period in which subsequent UL/DL transmission may take place. The subsequent transmission(s) as described in above alternatives could be a time period in which the UE may perform UL transmission or DL reception.
The above implementations could be applicable for (and/or supported by) Reduced Capability NR Device (or namely NR_Light device). The above implementations could be applicable for (and/or supported by) normal NR Device.
The UE may initiate the small data transmission procedure on a Serving Cell other than the last (Primary) Serving Cell in RRC_CONNECTED state. The UE may initiate the small data transmission procedure on the same Serving Cell as the last (Primary) Serving Cell in RRC_CONNECTED state.
In one embodiment, the UE could monitor the PDCCH, based on the first PDCCH-related configuration, for the at least one subsequent transmission if (or when) the second PDCCH-related configuration is not received by the UE. Furthermore, the UE could receive the second PDCCH-related configuration in the system information, a Msg4, a MSGB, or a RRCRelease message.
In one embodiment, the first PDCCH-related configuration and/or the second PDCCH-related configuration may include at least one of a search space configuration or a Control Resource Set (CORESET) configuration. The search space configuration may be associated with a common search space.
In one embodiment, the system information may include a third PDCCH-related configuration for monitoring the PDCCH during a RA procedure not for SDT. The at least one subsequent transmission could be for Uplink (UL) and could be scheduled through dynamic uplink grant. In addition, the SDT procedure could be a RRC connection resume procedure.
Referring back to
In one embodiment, the network node could transmit the PDCCH, based on the first PDCCH-related configuration, for the at least one subsequent transmission if (or when) the network node does not provide the second PDCCH-related configuration to the UE. Furthermore, the network node could provide the second PDCCH-related configuration in the system information, a Msg4, a MS GB, or a RRCRelease message.
In one embodiment, the first PDCCH-related configuration and/or the second PDCCH-related configuration may include at least one of a search space configuration or a CORESET configuration. The system information may include a third PDCCH-related configuration for monitoring the PDCCH during a RA procedure not for SDT.
Referring back to
In one embodiment, the UE may acquire the first PDCCH-related configuration from a first System Information of the Cell. The first System Information of the Cell may be System Information Block Type 1 (SIB1).
In one embodiment, before the monitoring PDCCH based on the second PDCCH-related configuration, the UE could acquire the second PDCCH-related configuration from a second System Information of the Cell. The second PDCCH-related configuration may be the same as the first PDCCH-related configuration. Alternatively, the second PDCCH-related configuration may be different from the first PDCCH-related configuration. The second System Information of the Cell may be System Information Block Type 1 (SIB1). Alternatively, the second System Information of the Cell may be a System Information Block other than System Information Block Type 1 (SIB1).
In one embodiment, before the monitoring PDCCH based on the second PDCCH-related configuration, the UE may receive, from the network node, the second PDCCH-related configuration in a downlink message during the RA procedure for SDT. The UE may consider the RA procedure for SDT completed in response to receiving the downlink message during the RA procedure for SDT.
In one embodiment, before the monitoring PDCCH based on the second PDCCH-related configuration, the UE may restore the second PDCCH-related configuration from a UE Inactive AS context. The UE could use the second PDCCH-related configuration for monitoring PDCCH while the UE was in RRC_CONNECTED state. The UE could store RRC configurations in the UE Inactive AS context upon state transition from RRC_CONNECTED state to RRC_INACTIVE state, wherein the RRC configurations comprise the second PDCCH-related configuration.
In one embodiment, before the monitoring PDCCH based on the second PDCCH-related configuration, the UE may receive, from the network node, a RRCRelease message triggering state transition of the UE from RRC_CONNECTED state to RRC_INACTIVE state, wherein the RRCRelease message comprises the second PDCCH-related configuration.
In one embodiment, the first PDCCH-related configuration may be a Control Resource Set (CORESET) configuration, a search space configuration, or a TCI states configuration for PDCCH, a CORESET configuration. The second PDCCH-related configuration may be a search space configuration or a TCI states configuration for PDCCH.
In one embodiment, the subsequent transmission(s) may comprise at least one UL transmission from the UE to the Cell. The subsequent transmission(s) may also comprise at least one DL transmission from the Cell to the UE. The subsequent transmission(s) could be scheduled by the network through dynamic uplink grant or dynamic downlink assignment. The subsequent transmission(s) could also be scheduled by the network through configured uplink grant or configured downlink assignment.
Referring back to
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 in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
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. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
In addition, the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (“IC”), an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
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.
The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a “processor”) such the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Moreover, in some aspects any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects a computer program product may comprise packaging materials.
While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.
The present application claims the benefit of U.S. Provisional Patent Application Ser. Nos. 63/079,890, 63/079,897, 63/079,911, and 63/079,934 filed on Sep. 17, 2020, the entire disclosures of which are incorporated herein in their entirety by reference.
Number | Date | Country | |
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63079890 | Sep 2020 | US | |
63079897 | Sep 2020 | US | |
63079911 | Sep 2020 | US | |
63079934 | Sep 2020 | US |