Patent Description:
3GPP documents R2-<NUM> and R2-<NUM> discuss discontinuous reception (DRX) for MBS multicast, in particular conditions for starting drx-HARQ-RTT-TimerDL and drx-HARQ-RTT-Timer-PTM.

In accordance with the present disclosure, one device and one method are provided and are defined in the independent claims, respectively. The dependent claims define preferred embodiments thereof.

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), <NUM>rd Generation Partnership Project (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) wireless access for <NUM>, 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: <NPL>"; <NPL>"; <NPL>"; <NPL> "; <NPL> "; <NPL>"; <NPL>.

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

In the embodiment, antenna groups each may be designed to communicate to access terminals in a sector of the areas covered by access network <NUM>.

In communication over forward links <NUM> and <NUM>, the transmitting antennas of access network <NUM> may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals <NUM> and <NUM>. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage may normally cause less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to 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 eNodeB (eNB), a Next Generation NodeB (gNB), or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

<FIG> presents an embodiment of a transmitter system <NUM> (also known as the access network) and a receiver system <NUM> (also known as access terminal (AT) or user equipment (UE)) in a multiple-input and multiple-output (MIMO) system <NUM>. At the transmitter system <NUM>, traffic data for a number of data streams may be provided from a data source <NUM> to a transmit (TX) data processor <NUM>.

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

The coded data for each data stream may be multiplexed with pilot data using orthogonal frequency-division multiplexing (OFDM) techniques. The pilot data may typically be 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 may then be modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-ary phase shift keying (M-PSK), or M-ary quadrature amplitude modulation (M-QAM)) selected for that data stream to provide modulation symbols. The data rate, coding, and/or modulation for each data stream may be determined by instructions performed by processor <NUM>.

The modulation symbols for data streams are then provided to a TX MIMO processor <NUM>, which may further process the modulation symbols (e.g., for OFDM). In certain embodiments, TX MIMO processor <NUM> may apply beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter <NUM> receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and/or upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NT modulated signals from transmitters 222a through 222t may then be transmitted from NT antennas 224a through 224t, respectively.

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

An RX data processor <NUM> then receives and/or processes the NR received symbol streams from NR receivers <NUM> based on a particular receiver processing technique to provide NT "detected" symbol streams. The RX data processor <NUM> may then demodulate, deinterleave, and/or decode each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor <NUM> may be complementary to that performed by TX MIMO processor <NUM> and TX data processor <NUM> at transmitter system <NUM>.

A processor <NUM> may periodically determine which pre-coding matrix to use (discussed below).

The reverse link message may then be processed by a TX data processor <NUM>, which may also receive traffic data for a number of data streams from a data source <NUM>, modulated by a modulator <NUM>, conditioned by transmitters 254a through 254r, and/or transmitted back to transmitter system <NUM>.

Processor <NUM> may then determine which pre-coding matrix to use for determining the beamforming weights and may then process the extracted message.

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

<FIG> is a simplified block diagram of the program code <NUM> shown in <FIG> in accordance with one embodiment of the disclosed subject matter. In this embodiment, the program code <NUM> includes an application layer <NUM>, a Layer <NUM> portion <NUM>, and a Layer <NUM> portion <NUM>, and is coupled to a Layer <NUM> portion <NUM>. The Layer <NUM> portion <NUM> may perform radio resource control. The Layer <NUM> portion <NUM> may perform link control. The Layer <NUM> portion <NUM> may perform and/or implement physical connections.

One or more parts of <NPL>) are quoted below:.

The IE SC-MTCH-InfoList provides the list of ongoing MBMS sessions transmitted via SC-MRB and for each MBMS session, the associated G-RNTI and scheduling information.

The MAC entity may be configured by RRC with a DRX functionality that controls the UE's PDCCH monitoring activity for the MAC entity's C-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, Semi-Persistent Scheduling C-RNTI (if configured), UL Semi-Persistent Scheduling V-RNTI (if configured), eIMTA-RNTI (if configured), SL-RNTI (if configured), SL-V-RNTI (if configured), CC-RNTI (if configured), SRS-TPC-RNTI (if configured), and AUL C-RNTI (if configured). When in RRC_CONNECTED, if DRX is configured, the MAC entity is allowed to monitor the PDCCH discontinuously using the DRX operation specified in this clause; otherwise the MAC entity monitors the PDCCH continuously. When using DRX operation, the MAC entity shall also monitor PDCCH according to requirements found in other clauses of this specification. RRC controls DRX operation by configuring the timers onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer (for HARQ processes scheduled using <NUM> TTI, one per DL HARQ process except for the broadcast process), drx-RetransmissionTimerShorttTI (for HARQ processes scheduled using short TTI, one per DL HARQ process), drx-ULRetransmissionTimer (for HARQ processes scheduled using <NUM> TTI, one per asynchronous UL HARQ process), drx-ULRetransmissionTimerShorttTI (for HARQ processes scheduled using short TTI, one per asynchronous UL HARQ process), the longDRX-Cycle, the value of the drxStartOffset and optionally the drxShortCycleTimer and shortDRX-Cycle. A HARQ RTT timer per DL HARQ process (except for the broadcast process) and UL HARQ RTT Timer per asynchronous UL HARQ process is also defined (see clause <NUM>).

When a DRX cycle is configured, the Active Time includes the time while:.

Each G-RNTI and, for NB-IoT UEs, BL UEs or UEs in enhanced coverage, each SC-RNTI of the MAC entity may be configured by RRC with a DRX functionality that controls the UE's PDCCH monitoring activity for this G-RNTI and SC-RNTI as specified in TS <NUM> [<NUM>]. When in RRC_IDLE or RRC_CONNECTED, if DRX is configured, the MAC entity is allowed to monitor the PDCCH for this G-RNTI or SC-RNTI discontinuously using the DRX operation specified in this clause; otherwise the MAC entity monitors the PDCCH for this G-RNTI or SC-RNTI continuously. For each G-RNTI or SC-RNTI of the MAC entity, RRC controls its DRX operation by configuring the timers onDurationTimerSCPTM, drx-InactivityTimerSCPTM, the SCPTM-SchedulingCycle and the value of the SCPTM-SchedulingOffset for G-RNTI and for SC-RNTI. The DRX operation specified in this clause is performed independently for each G-RNTI and SC-RNTI and independently from the DRX operation specified in subcaluse <NUM>.

When DRX is configured for a G-RNTI or for SC-RNTI, the Active Time includes the time while:.

When DRX is configured for a G-RNTI or for SC-RNTI as specified in TS <NUM> [<NUM>], the MAC entity shall for each subframe for this G-RNTI or SC-RNTI:.

The MAC entity may be configured by RRC with a DRX functionality that controls the UE's PDCCH monitoring activity for the MAC entity's C-RNTI, CI-RNTI, CS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, TPC-SRS-RNTI, AI-RNTI, SL-RNTI, SLCS-RNTI and SL Semi-Persistent Scheduling V-RNTI. When using DRX operation, the MAC entity shall also monitor PDCCH according to requirements found in other clauses of this specification. When in RRC_CONNECTED, if DRX is configured, for all the activated Serving Cells, the MAC entity may monitor the PDCCH discontinuously using the DRX operation specified in this clause; otherwise the MAC entity shall monitor the PDCCH as specified in TS <NUM> [<NUM>].

RRC controls DRX operation by configuring the following parameters:.

Serving Cells of a MAC entity may be configured by RRC in two DRX groups with separate DRX parameters. When RRC does not configure a secondary DRX group, there is only one DRX group and all Serving Cells belong to that one DRX group. When two DRX groups are configured, each Serving Cell is uniquely assigned to either of the two groups. The DRX parameters that are separately configured for each DRX group are: drx-onDurationTimer, drx-InactivityTimer. The DRX parameters that are common to the DRX groups are: drx-SlotOffset, drx-RetransmissionTimerDL, dr- RetransmissionTimerUL, drx-LongCycleStartOffset, drx-ShortCycle (optional), drx-ShortCycleTimer (optional), drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL, downlinkHARQ-FeedbackDisabled (optional) and uplink-HARQ-Mode (optional).

When DRX is configured, the Active Time for Serving Cells in a DRX group includes the time while:.

When DRX is configured, the MAC entity shall:.

Regardless of whether the MAC entity is monitoring PDCCH or not on the Serving Cells in a DRX group, the MAC entity transmits HARQ feedback, aperiodic CSI on PUSCH, and aperiodic SRS defined in TS <NUM> [<NUM>] on the Serving Cells in the DRX group when such is expected.

The MAC entity needs not to monitor the PDCCH if it is not a complete PDCCH occasion (e.g. the Active Time starts or ends in the middle of a PDCCH occasion).

For MBS multicast, the MAC entity may be configured by RRC with a DRX functionality per G-RNTI or per G-CS-RNTI that controls the UE's PDCCH monitoring activity for the MAC entity's G-RNTI(s) and G-CS-RNTI(s) as specified in TS <NUM> [<NUM>]. When in RRC_CONNECTED, if multicast DRX is configured, the MAC entity is allowed to monitor the PDCCH for this G-RNTI or G-CS-RNTI discontinuously using the multicast DRX operation specified in this clause; otherwise the MAC entity monitors the PDCCH for this G-RNTI or G-CS-RNTI as specified in TS <NUM> [<NUM>]. The multicast DRX operation specified in this clause is performed independently for each G-RNTI or G-CS-RNTI and independently from the DRX operation specified in clauses <NUM> and <NUM>.

RRC controls multicast DRX operation per G-RNTI or per G-CS-RNTI by configuring the following parameters:.

When multicast DRX is configured for a G-RNTI or G-CS-RNTI, the Active Time includes the time while:.

When multicast DRX is configured for a G-RNTI or G-CS-RNTI, the MAC entity shall for this G-RNTI or G-CS-RNTI:.

NOTE: A PDCCH indicating activation of multicast SPS is considered to indicate a new transmission.

One or more parts of <NPL>) are quoted below. Notably, Figure <NUM>. <NUM>-<NUM> of Section <NUM>. <NUM> of <NPL>), entitled "Downlink Layer <NUM> Architecture for Multicast Session", is reproduced herein as <FIG>. Figure <NUM>. <NUM>-<NUM> of Section <NUM>. <NUM> of <NPL>), entitled "Downlink Layer <NUM> Architecture for Broadcast Session", is reproduced herein as <FIG>.

NR system enables resource efficient delivery of multicast/broadcast services (MBS).

For broadcast communication service, the same service and the same specific content data are provided simultaneously to all UEs in a geographical area (i.e., all UEs in the broadcast service area are authorized to receive the data). A broadcast communication service is delivered to the UEs using a broadcast session. A UE can receive a broadcast communication service in RRC_IDLE, RRC_INACTIVE and RRC_CONNECTED state.

For multicast communication service, the same service and the same specific content data are provided simultaneously to a dedicated set of UEs (i.e., not all UEs in the multicast service area are authorized to receive the data). A multicast communication service is delivered to the UEs using a multicast session. A UE can receive a multicast communication service in RRC _CONNECTED state with mechanisms such as PTP and/or PTM delivery, as defined in clause <NUM>. HARQ feedback/retransmission can be applied to both PTP and PTM transmission.

The overall NG-RAN architecture specified in clause <NUM> applies for NR MBS. MBS multicast can only be supported in MCG side in NE-DC and NR-DC scenarios, i.e., only for MN-terminated MCG MRB; the configuration of MBS broadcast on SCG is not supported for the UE.

The QoS model for NR MBS can be found in TS <NUM> [<NUM>].

Figure <NUM>. <NUM>-<NUM> and <NUM>. <NUM>-<NUM> depict the downlink Layer <NUM> architecture for multicast session and broadcast session respectively, where MBS protocol stack comprises the same layer <NUM> sublayers as described in clause <NUM> with the following differences:.

The following logical channels are used for MBS delivery:.

The following connections between logical channels and transport channels for group transmission exist:.

The following depicts the usage of RNTI for group transmission:.

There are two delivery modes as specified in TS <NUM> [<NUM>]:.

As specified in TS <NUM> [<NUM>], if the gNB supports MBS, the network shall use the 5GC Shared MBS traffic delivery in which case an MBS Session Resource context for a multicast session is setup in the gNB when the first UE joins the multicast session.

For MBS shared delivery mode, shared NG-U resources are used to provide MBS user data to the gNB. The gNB initiates the Multicast Distribution Setup procedure towards the 5GC, to allocate shared NG-U resources for a multicast session. In case multiple MBS session areas are associated with the same multicast session for location dependent MBS services, multiple NG-U shared resources are established for the same multicast session per MBS Area Session ID served by the gNB.

A shared NG-U resource applies one of the following transport options:.

For 5GC Shared MBS traffic delivery an MBS Session Resource comprises one or several MRBs. If minimisation of data loss is applied for a given MRB, synchronisation of allocation of PDCP COUNT values is applied by either or a combination of the following methods:.

If PDCP COUNT values are derived from a DL MBS QFI Sequence Number provided on NG-U and only one QoS Flow is mapped to an MRB, the gNB shall set the PDCP COUNT value of PDCP PDU to the value of the DL MBS QFI Sequence Number provided with the received packet over NG-U. If PDCP COUNT values are derived from a DL MBS QFI Sequence Number provided on NG-U and multiple QoS Flows are mapped to an MRB, the gNB may derive the PDCP COUNT value of the PDCP PDU from the sum of the DL MBS QFI Sequence Numbers of the QoS Flows mapped to this MRB.

For multicast service, gNB may deliver Multicast MBS data packets using the following methods:.

If a UE is configured with both PTM and PTP transmissions, a gNB dynamically decides whether to deliver multicast data by PTM leg and/or PTP leg for a given UE based on the protocol stack defined in clause <NUM>. <NUM>, based on information such as MBS Session QoS requirements, number of joined UEs, UE individual feedback on reception quality, and other criteria. The same QoS requirements apply regardless of the decision.

UE can receive MBS multicast data either from a PCell or a single SCell at a time.

The following DRX configurations for PTM/PTP transmission are possible:.

A common frequency resource configured by SRB is defined for multicast scheduling as an 'MBS frequency region' with a number of contiguous PRBs confined within and with the same numerology as the DL BWP, but multicast scheduling may have specific characteristics (e.g., PDCCH, PDSCH and SPS configurations).

Two HARQ-ACK reporting modes are defined for MBS:.

HARQ-ACK feedback for multicast can be enabled or disabled by higher layer configuration per G-RNTI or per G-CS-RNTI and/or indication in the DCI scheduling multicast transmission.

This clause is applicable only for PDCCH receptions, PDSCH receptions, and PUCCH transmissions for MBS on a serving cell. DCI formats with CRC scrambled by G-RNTI or G-CS-RNTI scheduling PDSCH receptions are referred to as multicast DCI formats and the PDSCH receptions are referred to as multicast PDSCH receptions. DCI formats with CRC scrambled by MCCH-RNTI or G-RNTI for MTCH scheduling PDSCH receptions are referred to as broadcast DCI formats and the PDSCH receptions are referred to as broadcast PDSCH receptions. HARQ-ACK information associated with multicast DCI formats or multicast PDSCH receptions is referred to as multicast HARQ-ACK information.

A UE can be provided one or more G-RNTIs per serving cell for scrambling the CRC of multicast DCI formats for scheduling PDSCH receptions. The UE can be provided one or more G-CS-RNTI per serving cell for scrambling the CRC of multicast DCI formats providing activation/release for SPS PDSCH receptions.

A UE can be configured by cfr-Config-MCCH-MTCH an MBS frequency resource for PDCCH and PDSCH receptions providing MCCH and MTCH [<NUM>, TS <NUM>]; otherwise, the MBS frequency resource is same as for the CORESET with index <NUM> that is associated with the Type0-PDCCH CSS set for PDCCH and PDSCH receptions providing MCCH and MTCH. A UE monitors PDCCH for scheduling PDSCH receptions for MCCH or MTCH as described in clause <NUM>.

In clauses referring to a higher layer parameter value provided by PDCCH-ConfigCommon or PDSCH-ConfigCommon, when applicable a corresponding higher layer parameter value for MCCH/MTCH PDCCH receptions or PDSCH receptions, respectively, is provided as described in [<NUM>, TS <NUM>].

A UE is not required to simultaneously receive PDSCHs for MCCH or MTCH on two serving cells. A UE is not required to simultaneously receive on a serving cell.

A UE in the RRC_CONNECTED state is not required to simultaneously receive on a serving cell.

A UE can be configured, per DL BWP by cfr-Config-Multicast, an MBS frequency resource within the DL BWP for PDCCH and PDSCH receptions [<NUM>, TS <NUM>]. If cfr-Config-Multicast does not include locationAndBandwidth-Multicast, the MBS frequency resource is the active DL BWP. The UE is not required to simultaneously receive PDSCHs on two serving cells. In clauses referring to a higher layer parameter value provided by PDCCH-Config or PDSCH-Config or SPS-Config for a DL BWP, when applicable a corresponding higher layer parameter value for multicast PDCCH, PDSCH, or SPS PDSCH receptions is provided as described in [<NUM>, TS <NUM>].

In clauses referring to a higher layer parameter value provided by a first or second PUCCH-Config, when applicable a corresponding higher layer parameter value for PUCCH transmissions associated with multicast PDCCH or PDSCH receptions is provided as described in [<NUM>, TS <NUM>]. In clauses referring to a higher layer parameter value provided by SPS-PUCCH-AN or SPS-PUCCH-AN-List, when applicable a corresponding higher layer parameter value for PUCCH transmissions associated with multicast SPS PDSCH receptions is provided as described in [<NUM>, TS <NUM>]. In clauses referring to a higher layer parameter value provided by pdsch-HARQ-ACK-Codebook or pdsch-HARQ-ACK-CodebookList, when applicable a corresponding higher layer parameter value for HARQ-ACK codebooks associated with multicast HARQ-ACK information is provided as described in [<NUM>, TS <NUM>].

A UE monitors PDCCH for scheduling PDSCH receptions or for activation/release of SPS PDSCH receptions for a corresponding SPS PDSCH configuration as described in clause <NUM>.

A UE can be configured by harq-Feedback-Option-Multicast for a G-RNTI, or by sps-HARQ-Feedback-Option-Multicast for a G-CS-RNTI, to provide HARQ-ACK information for a transport block reception associated with the G-RNTI or with the G-CS-RNTI, respectively, according to the first HARQ-ACK reporting mode or according to the second HARQ-ACK reporting mode. The UE determines a priority for a PUCCH transmission with multicast HARQ-ACK information according to any HARQ-ACK reporting mode as described in clause <NUM> for a PUCCH transmission with unicast HARQ-ACK information.

For the first HARQ-ACK reporting mode, the UE generates HARQ-ACK information with ACK value when a UE correctly decodes a transport block or detects a DCI format indicating an SPS PDSCH release; otherwise, the UE generates HARQ-ACK information with NACK value, as described in clauses <NUM> and <NUM> through <NUM>.

For the second HARQ-ACK reporting mode, the UE does not transmit a PUCCH that would include only HARQ-ACK information with ACK values. The second HARQ-ACK reporting mode is not applicable for the first SPS PDSCH reception after activation of SPS PDSCH receptions for a SPS configuration, or for DCI formats having associated HARQ-ACK information without scheduling a PDSCH reception.

For the second HARQ-ACK reporting mode, when a number of HARQ-ACK information bits is one, a UE transmits a PUCCH only when the HARQ-ACK information bit has NACK value. For a PUCCH resource associated with PUCCH format <NUM>, the UE transmits the PUCCH as described in [<NUM>, TS <NUM>] by obtaining m<NUM> as described for HARQ-ACK information in clause <NUM>. <NUM> and by setting mcs = <NUM>. For a PUCCH resource associated with PUCCH format <NUM>, the UE transmits the PUCCH as described in [<NUM>, TS <NUM>] by setting b(<NUM>) = <NUM>.

For the second HARQ-ACK reporting mode and a UE configured with only one G-RNTI, the UE can be indicated by moreThanOneNackOnlyMode to provide the HARQ-ACK information bits in a PUCCH either according to the first HARQ-ACK reporting mode or by selecting a resource from a set of resources for the PUCCH transmission based on the values of the HARQ-ACK information bits as described in Table <NUM>-<NUM>. The UE generates HARQ-ACK information bits for the second HARQ-ACK reporting mode according to a Type-<NUM> HARQ-ACK codebook as described in clause <NUM>.

If a UE is provided pucch-ConfigurationListMulticast1 or pucch-ConfigurationListMulticast2 for PUCCH transmissions with a priority value, the UE transmits a PUCCH with the priority value according to pucch-ConfigurationListMulticast1 or pucch-ConfigurationListMulticast2 for each G-RNTI or G-CS-RNTI that the UE provides associated HARQ-ACK information according to the first HARQ-ACK reporting mode or the second HARQ-ACK reporting mode, respectively. For HARQ-ACK information associated only with the second HARQ-ACK reporting mode, when the UE is provided moreThanOneNackOnlyMode and the UE provides the HARQ-ACK information according to the first HARQ-ACK reporting mode and in response to at least one DCI format detection, the UE determines a PUCCH resource from pucch-ConfigurationListMulticast1, if provided; otherwise, the UE determines a PUCCH resource from pucch-Config/pucch-ConfigurationList.

A PDSCH reception providing an initial transmission of a transport block is scheduled only by a multicast DCI format. For the first HARQ-ACK reporting mode, a PDSCH reception providing a retransmission of the transport block can be scheduled either by a multicast DCI format using a same G-RNTI as the G-RNTI of the initial transmission of the transport block, or by a unicast DCI format using a C-RNTI [<NUM>, TS <NUM>].

An activation for SPS PDSCH receptions using a G-CS-RNTI for a corresponding SPS PDSCH configuration is provided only by a multicast DCI format as described in clause <NUM> by replacing CS-RNTI with the G-CS-RNTI. A release for SPS PDSCH receptions using a G-CS-RNTI for a corresponding SPS PDSCH configuration is provided by a multicast DCI format as described in clause <NUM> by replacing CS-RNTI with the G-CS-RNTI, or by a DCI format with CRC scrambled by CS-RNTI. For the first HARQ-ACK reporting mode and for a transport block that a UE received in a SPS PDSCH, a PDSCH reception providing a retransmission of the transport block can be scheduled either by a unicast DCI format using a CS-RNTI or by a multicast DCI format using a same G-CS-RNTI as the G-CS-RNTI of the initial transmission of the transport block [<NUM>, TS <NUM>].

A UE can be configured per G-RNTI or per G-CS-RNTI, by harq-FeedbackEnablerMulticast with value set to 'enabled', to provide HARQ-ACK information for PDSCH receptions. When the UE is not provided harq-FeedbackEnablerMulticast for a G-RNTI or G-CS-RNTI, or when the UE is provided harq-FeedbackEnablerMulticast with value set to 'disabled', the UE does not provide HARQ-ACK information for respective PDSCH receptions. If a UE is provided harq-FeedbackEnablerMulticast with value set to 'dci-enabler' for a G-RNTI or a G-CS-RNTI, the UE determines whether or not to provide the HARQ-ACK information for PDSCH receptions based on an indication by the multicast DCI format associated with the G-RNTI or the G-CS-RNTI [<NUM>, TS <NUM>].

If a UE would multiplex multicast HARQ-ACK information according to the second HARQ-ACK reporting mode with multicast HARQ-ACK information according to the first HARQ-ACK reporting mode, or unicast HARQ-ACK information, or CSI reports in a first PUCCH or in a PUSCH, as described in clauses <NUM> and <NUM>. <NUM>, the UE provides the HARQ-ACK information according to the first HARQ-ACK reporting mode. For resolving an overlapping among a second PUCCH with HARQ-ACK information according to the second HARQ-ACK reporting mode and other PUCCHs or PUSCHs prior to multiplexing the HARQ-ACK information in a PUCCH or PUSCH, the UE considers that the UE would transmit the second PUCCH when all values of the HARQ-ACK information are 'ACK'.

If a UE is provided multiple G-RNTIs or G-CS-RNTIs, a configuration for a HARQ-ACK codebook type applies to all G-RNTIs or G-CS-RNTIs.

One or more parts of<NPL>) are quoted below:.

The IE MAC-CellGroupConfig is used to configure MAC parameters for a cell group, including DRX.

One or more parts of R2-<NUM> are quoted below:.

In previous RAN2 meetings, the following agreement was reached.

However, in the current specification, the highlighted part is not reflected. In addition, for PTM retransmission via C-RNTI, RAN1 defines two optional UE capability: <NUM>-2d (PTP retransmission for multicast dynamic scheduling) and <NUM>-<NUM>-1d (PTP retransmission for SPS group-common PDSCH for multicast).

According to the current specification, even if UE does not support PTM retransmission via C-RNTI, the UE still start drx-HARQ-RTT-TimerDL for the corresponding HARQ process after receiving a PTM transmission, which will cause UE power waste.

Therefore, we propose RAN2 to clarify that UE doesn't need to start drx-HARQ-RTT-TimerDL for the corresponding HARQ process after receiving a PTM transmission if UE does not support PTM retransmission via C-RNTI.

In some examples, a first Discontinuous Reception (DRX) (e.g., a first DRX pattern and/or configuration) is associated with a Group Radio Network Temporary Identifier (G-RNTI), which may correspond to a multicast service. A network (e.g., a gNB) may transmit (e.g., newly transmit) data (e.g., the data may comprise a transport block (TB) and/or a Medium Access Control (MAC) Protocol/Packet Data Unit (PDU)) to a plurality of UEs by multicast. The data (transmitted to the plurality of UEs) may be addressed to the G-RNTI. The plurality of UEs may be associated with the G-RNTI. In some examples, the transmission of the data addressed to the G-RNTI corresponds to a new transmission by the network (e.g., the transmission is not a retransmission of the data). In some examples, after the transmission, if the transmission was not decoded successfully by a UE (of the plurality of UEs, for example), the network may retransmit the data to the UE (e.g., the specific UE), wherein the retransmitted data may be addressed to a Cell Radio Network Temporary Identifier (C-RNTI) (of the UE, for example). In some examples, the UE may be configured with a second DRX (e.g., a second DRX pattern and/or configuration) associated with the C-RNTI, thereby requiring that there be coordination between the first DRX and the second DRX for data reception.

When a UE receives/detects data addressed to a G-RNTI for a Hybrid Automatic Repeat Request (HARQ) process from a network (e.g., a gNB) and the UE does not decode the data successfully (e.g., the UE sends HARQ feedback indicating Negative Acknowledgement (NACK)), the UE (i) may start one or more G-RNTI-related timers (e.g., a DRX retransmission timer and/or HARQ Round Trip Time (RTT) Timer) associated with the G-RNTI for the HARQ process (e.g. the one or more G-RNTI-related timers may comprise drx-RetransmissionTimerDL-PTM), and/or (ii) may start one or more C-RNTI-related timers (e.g., a DRX retransmission timer and/or HARQ RTT Timer) associated with C-RNTI for the HARQ process (e.g. the one or more C-RNTI-related timers may comprise drx-RetransmissionTimerDL). In the present disclosure, the term "receives/detects" may refer to receives and/or detects. For example, DRX retransmissions associated with the G-RNTI and the C-RNTI may be started responsive to and/or after expiry of a G-RNTI HARQ RTT Timer (of the one or more G-RNTI-related timers, for example) and a C-RNTI HARQ RTT Timer (of the one or more C-RNTI-related timers, for example), respectively (e.g. drx-HARQ-RTT-TimerDL-PTM and drx-HARQ-RTT-TimerDL). In an example, DRX retransmissions associated with the G-RNTI (and/or a G-RNTI timer) may be started responsive to and/or after expiry of the G-RNTI HARQ RTT Timer (e.g. the G-RNTI HARQ RTT Timer may be drx-HARQ-RTT-TimerDL-PTM). In an example, DRX retransmissions associated with the C-RNTI (and/or a C-RNTI timer) may be started responsive to and/or after expiry of the C-RNTI HARQ RTT Timer (e.g. the C-RNTI HARQ RTT Timer may be drx-HARQ-RTT-TimerDL). In some examples, UE may determine to start a C-RNTI retransmission timer (e.g., a timer, such as DRX retransmission timer, of the one or more C-RNTI-related timers) based on first information. In some examples, the first information may comprise information (e.g., an indication) of a configuration, such as a Physical Downlink Control Channel (PDCCH) configuration and/or a Radio Resource Control (RRC) configuration. The first information (e.g., the configuration, such as the PDCCH configuration and/or the RRC configuration) may indicate that C-RNTI transmission (e.g., retransmission) may occur for the multicast transmission (addressed to G-RNTI, for example) for the same content (e.g., the same data, the same TB, the same MAC PDU, etc.). For example, the first information may indicate that C-RNTI transmission may be performed to retransmit content (e.g., data, TB, MAC PDU, etc.) transmitted via a (prior) multicast transmission (addressed to G-RNTI, for example). The C-RNTI transmission may be a unicast transmission. In some examples, the aforementioned timers (e.g., at least one of the one or more G-RNTI-related timers, the one or more C-RNTI-related timers, a DRX retransmission timer, a HARQ RTT Timer, the G-RNTI HARQ RTT Timer, the C-RNTI HARQ RTT Timer, drx-HARQ-RTT-TimerDL-PTM, drx-HARQ-RTT-TimerDL, etc.) may have different lengths. Embodiments are contemplated in which two or more of the aforementioned timers share the same length.

In some examples, when a UE receives/detects data (e.g. retransmission) addressed to C-RNTI for a HARQ process from gNB/network and UE does not decode the data successfully (e.g., the UE may send HARQ feedback indicating NACK), the UE (i) may start a DRX retransmission timer and/or HARQ RTT Timer associated with C-RNTI for the HARQ process (e.g. drx-RetransmissionTimerDL), and (ii) may not start DRX retransmission timer and/or HARQ RTT Timer associated with G-RNTI for the HARQ process (e.g. drx-RetransmissionTimerDL-PTM). In some examples, the UE may start the G-RNTI retransmission timer responsive to (e.g., upon) expiry of HARQ RTT Timer associated with G-RNTI for the HARQ process.

In some examples, if gNB receives a NACK (e.g., any NACK) for a multicast data from UE side (e.g., from a UE), gNB may retransmit the data through multicast (e.g., G-RNTI) and unicast (e.g., C-RNTI) for different UEs at (around) the same time and/or within a time period. When UE receives/detects a retransmission addressed to G-RNTI and/or C-RNTI for the HARQ process (associated with the multicast data, for example), the UE may stop both G-RNTI and C-RNTI retransmission timers. UE may not continue to monitor PDCCH for C-RNTI and/or G-RNTI retransmission (e.g., the UE may cease monitoring PDCCH for C-RNTI and/or G-RNTI retransmission after stopping both the G-RNTI and C-RNTI retransmission timers).

In some examples, assuming that UE is capable (and/or enabled and/or allowed and/or configured and/or indicated and/or instructed) to send HARQ feedback for a multicast (e.g., G-RNTI) data/Physical Downlink Shared Channel (PDSCH)/TB, two options may be available for the UE. In the present disclosure, the term "data/PDSCH/TB" may refer to data, a PDSCH and/or a TB. A first option of the two options may be sending Acknowledgement (ACK) (e.g., explicit ACK) on Physical Uplink Control Channel (PUCCH) if decoding (e.g., G-RNTI data/PDSCH decoding) of the multicast data/PDSCH/TB is successful; otherwise sending NACK. For example, according to the first option, the UE may send NACK if the UE does not successfully decode the multicast data/PDSCH/TB (e.g., in response to failing decoding the multicast data/PDSCH/TB). A second option of the two options may be (i) not sending ACK (even) if decoding (e.g., G-RNTI data/PDSCH decoding) of the multicast data/PDSCH/TB is successful, and (ii) sending NACK (on a common/shared resource on PUCCH, for example) if the decoding of the multicast data/PDSCH/TB is failed. In some examples, the UE may determine which option of the two options (for multicast data/PDSCH/TB, for example) based on a RRC configuration (e.g. harq-FeedbackEnablerMulticast and/or harq-FeedbackOptionMulticast), Downlink Control Information (DCI) and/or PDCCH. The first option may correspond to ack-nack mode and/or the second option may correspond to nack-only mode.

If a UE uses nack-only mode (for multicast data/PDSCH/TB, for example) (e.g. harq-FeedbackOptionMulticast = nack-only), the UE may (still) start unicast HARQ RTT Timer and/or unicast DRX retransmission timer when the UE receives/detects a multicast (e.g., G-RNTI) data/PDSCH/TB and the UE fails decoding the multicast (e.g., G-RNTI) data/PDSCH/TB. Considering that NACK may be sent from more than one UE, the UE starting the unicast HARQ RTT Timer and/or the unicast DRX retransmission timer based on failing to successfully decode the multicast (e.g., G-RNTI) data/PDSCH/TB may result in UE power waste since gNB/network may not schedule any corresponding unicast (e.g., C-RNTI) retransmission for a specific UE.

<FIG> illustrates a scenario <NUM> associated with a UE receiving a first multicast transmission <NUM>. In some examples, the UE receives/detects the first multicast transmission <NUM> using a configured downlink (DL) multicast resource (e.g., a pre-configured downlink multicast resource. In some examples, the configured downlink multicast resource comprises a configured (e.g., pre-configured) downlink multicast assignment. In some examples, the UE receives/detects the first multicast transmission <NUM> from a network (e.g., a gNB) at time t1. In some examples, the first multicast transmission <NUM> is addressed to a G-RNTI of a group of UEs (e.g., a plurality of UEs) comprising the UE. In some examples, the first multicast transmission <NUM> is associated with a first HARQ process. In some examples, the first multicast transmission <NUM> is a transmission of data/PDSCH/TB for the first HARQ process. In some examples, the UE starts an inactivity timer <NUM> at or after the time <NUM>. In some examples, the UE starts the inactivity timer <NUM> in response to receiving the first multicast transmission <NUM>. In some examples, the UE transmits HARQ feedback <NUM> indicating NACK at time t2. In some examples, the UE transmits (on a common/shared resource, for example) the HARQ feedback <NUM> indicating NACK based on the UE not successfully decoding the first multicast transmission <NUM> (e.g., decoding the first multicast transmission <NUM> is failed). In some examples, the HARQ feedback <NUM> indicating NACK is associated with the first HARQ process. The UE starts (both) a multicast RTT timer <NUM> (e.g., a multicast HARQ RTT timer) and a unicast RTT timer <NUM> (e.g., a unicast HARQ RTT timer). In some examples, the multicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL-PTM. In some examples, the unicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL. In some examples, the UE starts (both) the multicast RTT timer <NUM> and the unicast RTT timer <NUM> in response to transmitting the HARQ feedback <NUM> indicating NACK (and/or in response to failing to decode the first multicast transmission <NUM>). In some examples, the multicast RTT timer <NUM> and/or the unicast RTT timer <NUM> are associated with the first HARQ process. In some examples, at time t3, the UE starts a unicast retransmission timer <NUM> in response to expiry of the unicast RTT timer <NUM>. In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) retransmission (e.g., a unicast retransmission of the first multicast transmission <NUM>) while the unicast retransmission timer <NUM> is running. In some examples, at time t4, the UE starts a multicast retransmission timer <NUM> in response to expiry of the multicast RTT timer <NUM>. In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a multicast (e.g., G-RNTI) retransmission (e.g., a multicast retransmission of the first multicast transmission <NUM>) while the multicast retransmission timer <NUM> is running. In some examples, the multicast retransmission timer <NUM> and/or the unicast retransmission timer <NUM> are associated with the first HARQ process. In some examples, the multicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL-PTM. In some examples, the unicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL.

In some examples, the UE receives/detects a second multicast transmission <NUM> (e.g., a G-RNTI transmission) at time t5. In some examples, the second multicast transmission <NUM> is transmitted by the network (e.g., the gNB). In some examples, the second multicast transmission <NUM> is associated with the first HARQ process. In some examples, the second multicast transmission <NUM> is a transmission (e.g., retransmission) of the data/PDSCH/TB (of the first multicast transmission <NUM>) for the first HARQ process. In some examples, the second multicast transmission <NUM> comprises a retransmission (e.g., a G-RNTI retransmission) of the first multicast transmission <NUM>. In some examples, the network (e.g., the gNB) transmits the second multicast transmission <NUM> in response to the HARQ feedback <NUM> indicating NACK (and/or in response to other HARQ feedback from one or more other UEs of the group of UEs). In some examples, the UE stops the multicast retransmission timer <NUM> and/or the unicast retransmission timer <NUM> in response to receiving the second multicast transmission <NUM>.

Thus, the UE may perform control channel monitoring (e.g., active monitoring of a control channel, such as PDCCH) during a first period of time <NUM> (while the unicast retransmission timer <NUM> and/or the multicast retransmission timer <NUM> are running, for example). The first period of time <NUM> comprises a second period of time <NUM> during which the multicast retransmission timer <NUM> is not running (e.g., merely the unicast retransmission timer <NUM> is running during the second period of time <NUM>). In some examples, the control channel monitoring performed by the UE during the second period of time <NUM> is unproductive (and/or unnecessary and/or supplementary) since the network (e.g., the gNB) is not configured to retransmit the first multicast transmission <NUM> via a unicast (e.g., C-RNTI) retransmission. Thus, monitoring (e.g., actively monitoring) the control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) transmission (e.g., unicast retransmission of the first multicast transmission <NUM>) during the second period of time <NUM> may be a waste of power and/or resources of the UE.

<FIG> illustrates a scenario <NUM> associated with a UE receiving a first multicast transmission <NUM>. In some examples, the UE receives/detects the first multicast transmission <NUM> using a configured downlink multicast resource (e.g., a pre-configured downlink multicast resource. In some examples, the configured downlink multicast resource comprises a configured (e.g., pre-configured) downlink multicast assignment. In some examples, the UE receives/detects the first multicast transmission <NUM> from a network (e.g., a gNB) at time t1. In some examples, the first multicast transmission <NUM> is addressed to a G-RNTI of a group of UEs (e.g., a plurality of UEs) comprising the UE. In some examples, the first multicast transmission <NUM> is associated with a first HARQ process. In some examples, the first multicast transmission <NUM> is a transmission of data/PDSCH/TB for the first HARQ process. In some examples, the UE starts an inactivity timer <NUM> at or after the time <NUM>. In some examples, the UE starts the inactivity timer <NUM> in response to receiving the first multicast transmission <NUM>. In some examples, the UE transmits HARQ feedback <NUM> indicating NACK at time t2. In some examples, the UE transmits (on a common/shared resource, for example) the HARQ feedback <NUM> indicating NACK based on the UE not successfully decoding the first multicast transmission <NUM> (e.g., decoding the first multicast transmission <NUM> is failed). In some examples, the HARQ feedback <NUM> indicating NACK is associated with the first HARQ process. The UE starts (both) a multicast RTT timer <NUM> (e.g., a multicast HARQ RTT timer) and a unicast RTT timer <NUM> (e.g., a unicast HARQ RTT timer). In some examples, the multicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL-PTM. In some examples, the unicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL. In some examples, the UE starts (both) the multicast RTT timer <NUM> and the unicast RTT timer <NUM> in response to transmitting the HARQ feedback <NUM> indicating NACK (and/or in response to failing to decode the first multicast transmission <NUM>). In some examples, the multicast RTT timer <NUM> and/or the unicast RTT timer <NUM> are associated with the first HARQ process. In some examples, at time t3, the UE starts a unicast retransmission timer <NUM> in response to expiry of the unicast RTT timer <NUM>. In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) retransmission (e.g., a unicast retransmission of the first multicast transmission <NUM>) while the unicast retransmission timer <NUM> is running. In some examples, at time t4, the UE starts a multicast retransmission timer <NUM> in response to expiry of the multicast RTT timer <NUM>. In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a multicast (e.g., G-RNTI) retransmission (e.g., a multicast retransmission of the first multicast transmission <NUM>) while the multicast retransmission timer <NUM> is running. In some examples, the multicast retransmission timer <NUM> and/or the unicast retransmission timer <NUM> are associated with the first HARQ process. In some examples, the multicast retransmission timer <NUM> expires at time t5. In some examples, the unicast retransmission timer <NUM> expires at time t6 after time t5. In some examples, the multicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL-PTM. In some examples, the unicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL.

Thus, the UE may perform control channel monitoring (e.g., active monitoring of a control channel, such as PDCCH) during a first period of time <NUM> (while the unicast retransmission timer <NUM> and/or the multicast retransmission timer <NUM> are running, for example). The first period of time <NUM> comprises a second period of time <NUM> and a third period of time <NUM> during which the multicast retransmission timer <NUM> is not running (e.g., merely the unicast retransmission timer <NUM> is running during the second period of time <NUM> and the third period of time <NUM>). In some examples, the control channel monitoring performed by the UE during the second period of time <NUM> and the third period of time <NUM> is unproductive (and/or unnecessary and/or supplementary) since the network (e.g., the gNB) is not configured to retransmit the first multicast transmission <NUM> via a unicast (e.g., C-RNTI) retransmission. Thus, monitoring (e.g., actively monitoring) the control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) transmission (e.g., unicast retransmission of the first multicast transmission <NUM>) during the second period of time <NUM> and the third period of time <NUM> may be a waste of power and/or resources of the UE.

In accordance with some embodiments, the present disclosure provides techniques that when implemented provide for increased efficiency of the UE and/or avoid power wastage and/or resource wastage of the UE.

<FIG> illustrates a scenario <NUM> associated with a UE receiving a first multicast transmission <NUM>. In some examples, the UE receives/detects the first multicast transmission <NUM> from a network (e.g., a gNB) at time t1. In some examples, the UE receives/detects the first multicast transmission <NUM> using a configured downlink multicast resource (e.g., a pre-configured downlink multicast resource. In some examples, the configured downlink multicast resource comprises a configured (e.g., pre-configured) downlink multicast assignment. In some examples, the first multicast transmission <NUM> is addressed to a G-RNTI of a group of UEs (e.g., a plurality of UEs) comprising the UE. In some examples, the first multicast transmission <NUM> is associated with a first HARQ process. In some examples, the first multicast transmission <NUM> is a transmission of data/PDSCH/TB for the first HARQ process. In some examples, the UE starts an inactivity timer <NUM> at or after the time <NUM>. In some examples, the UE starts the inactivity timer <NUM> in response to receiving the first multicast transmission <NUM>. In some examples, the UE transmits HARQ feedback <NUM> indicating NACK at time t2. In some examples, the UE transmits the HARQ feedback <NUM> indicating NACK based on the UE not successfully decoding the first multicast transmission <NUM> (e.g., decoding the first multicast transmission <NUM> is failed). In some examples, the HARQ feedback <NUM> indicating NACK is associated with the first HARQ process.

In some examples, the UE determines whether to start a multicast RTT timer <NUM> (e.g., a multicast HARQ RTT timer) and/or a unicast RTT timer <NUM> (e.g., a unicast HARQ RTT timer). In some examples, the multicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL-PTM. In some examples, the unicast RTT timer <NUM> comprises drx-HARQ-RTT-TimerDL. In some examples, the multicast RTT timer <NUM> and/or the unicast RTT timer <NUM> are associated with the first HARQ process. In some examples, the UE determines whether to start the multicast RTT timer <NUM> and/or the unicast RTT timer <NUM> in response to transmitting the HARQ feedback <NUM> indicating NACK (and/or in response to failing to decode the first multicast transmission <NUM>). In some examples, the UE determines to start the multicast RTT timer <NUM>. In some examples, the UE determines to start the multicast RTT timer <NUM> in response to transmitting the HARQ feedback <NUM> indicating NACK (and/or in response to failing to decode the first multicast transmission <NUM>). In some examples, the UE starts the multicast RTT timer <NUM> in response to determining to start the multicast RTT timer <NUM>. In some examples, the UE starts the multicast RTT timer <NUM> at time t2.

In some examples, the UE determines whether to start the unicast RTT timer <NUM> based on a feedback mode (e.g., HARQ feedback mode). In some examples, the feedback mode is used and/or indicated for the first multicast transmission <NUM>. Alternatively and/or additionally, the feedback mode may be associated with the first HARQ process (e.g., the feedback mode may be used and/or indicated for the first HARQ process). In some examples, the UE determines the feedback mode based on an indication of the feedback mode, which may be received from the network (e.g., the gNB). In some examples, the UE receives a configuration (from the network, for example) and determines the feedback mode based on the configuration (e.g., the configuration is indicative of the feedback mode). In some examples, the UE determines to start the unicast RTT timer <NUM> based on the feedback mode being ack-nack mode. In some examples, the UE determines not to start the unicast RTT timer <NUM> based on the feedback mode being nack-only mode.

In some examples, the UE determines whether to start the unicast RTT timer <NUM> based on a first configuration (e.g., a configurable configuration in RRC layer). In some examples, the UE determines to start the unicast RTT timer <NUM> based on the first configuration (e.g., RRC configuration) indicating a first value. In some examples, the UE determines not to start the unicast RTT timer <NUM> based on the first configuration indicating a second value.

In some examples, the UE determines whether to start the unicast RTT timer <NUM> based on a type of resource used to send the HARQ feedback <NUM> indicating NACK (e.g., the UE determines whether to start the unicast RTT timer <NUM> based on whether the resource is common, shared, and/or dedicated). In some examples, the UE determines to start the unicast RTT timer <NUM> based on the HARQ feedback <NUM> (e.g., NACK) being transmitted via a dedicated and/or specific PUCCH resource (e.g., a PUCCH resource that is dedicated to being used by the UE and/or is not usable by other UEs). In some examples, the UE determines not to start the unicast RTT timer <NUM> based on the HARQ feedback <NUM> (e.g., NACK) being transmitted via a common and/or shared PUCCH resource (e.g., a PUCCH resource for more than one UE that is not dedicated to being used by the UE).

In some examples, the UE determines whether to start the unicast RTT timer <NUM> based on whether the UE is configured with a Configured Scheduling Radio Network Temporary Identifier (CS-RNTI). In some examples, the CS-RNTI is used for detecting a transmission (e.g., a retransmission) of the data/PDSCH/TB (of the first multicast transmission <NUM>) associated with the first HARQ process. In some examples, the UE determines to start the unicast RTT timer <NUM> based on the UE being configured with the CS-RNTI (e.g., the UE may be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process). In some examples, the UE determines not to start the unicast RTT timer <NUM> based on the UE not being configured with the CS-RNTI (e.g., the UE may not be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process).

In some examples, the UE determines not to start the unicast RTT timer <NUM> (at time t2, for example) based on (i) the feedback mode being nack-only mode, (ii) the first configuration (e.g., the RRC configuration) indicating the second value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the common and/or shared PUCCH resource, and/or (iv) the UE not being configured with the CS-RNTI (e.g., the UE may not be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process).

In some examples, the UE determines to start the unicast RTT timer <NUM> (at time t2, for example) based on (i) the feedback mode being ack-nack mode, (ii) the first configuration (e.g., the RRC configuration) indicating the first value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the dedicated and/or specific PUCCH resource, and/or (iv) the UE being configured with the CS-RNTI (e.g., the UE may be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process).

In some examples, the UE determines to start the multicast RTT timer <NUM> and not to start the unicast RTT timer <NUM> based on (i) the feedback mode being nack-only mode, (ii) the first configuration (e.g., the RRC configuration) indicating the second value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the common and/or shared PUCCH resource, and/or (iv) the UE not being configured with the CS-RNTI (e.g., the UE may not be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process). For example, the UE may start the multicast RTT timer <NUM> at time t2 without starting the unicast RTT timer <NUM> (such as shown in the scenario <NUM> of <FIG>) based on (i) the feedback mode being nack-only mode, (ii) the first configuration (e.g., the RRC configuration) indicating the second value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the common and/or shared PUCCH resource, and/or (iv) the UE not being configured with the CS-RNTI (e.g., the UE may not be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process).

In some examples, the UE determines to start (both) the multicast RTT timer <NUM> and the unicast RTT timer <NUM> based on (i) the feedback mode being ack-nack mode, (ii) the first configuration (e.g., the RRC configuration) indicating the first value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the dedicated and/or specific PUCCH resource, and/or (iv) the UE being configured with the CS-RNTI (e.g., the UE may be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process). For example (not shown in <FIG>), the UE may start the multicast RTT timer <NUM> and the unicast RTT timer <NUM> at time t2 based on (i) the feedback mode being ack-nack mode, (ii) the first configuration (e.g., the RRC configuration) indicating the first value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the dedicated and/or specific PUCCH resource, and/or (iv) the UE being configured with the CS-RNTI (e.g., the UE may be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process).

In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) retransmission while a unicast retransmission timer <NUM> is running. In some examples, the unicast retransmission timer <NUM> and/or a multicast retransmission timer <NUM> are associated with the first HARQ process. In some examples, the multicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL-PTM. In some examples, the unicast retransmission timer <NUM> comprises drx-RetransmissionTimerDL.

In some examples, the UE does not start the unicast retransmission timer <NUM> (since the unicast RTT timer <NUM> was not started and/or did not expire, for example). In some examples, at time t3, the UE starts the multicast retransmission timer <NUM> in response to expiry of the multicast RTT timer <NUM>. In some examples, the UE is configured to monitor (e.g., actively monitor) a control channel (e.g., PDCCH) for a multicast (e.g., G-RNTI) retransmission (e.g., a multicast retransmission of the first multicast transmission <NUM>) while the multicast retransmission timer <NUM> is running. In some examples, the multicast retransmission timer <NUM> expires at time t4.

Embodiments are contemplated in which the UE (i) starts the unicast RTT timer <NUM> at time t2 (along with the multicast RTT timer <NUM>, for example), and (ii) determines whether to start the unicast retransmission timer <NUM> (in response to expiry of the unicast RTT timer <NUM>, for example) based on the feedback mode, the first configuration, the type of resource used to send the HARQ feedback <NUM>, whether the UE is configured with the CS-RNTI, and/or other information. In some examples, the UE determines not to start the unicast retransmission timer <NUM> (in response to expiry of the unicast RTT timer <NUM>, for example) based on (i) the feedback mode being nack-only mode, (ii) the first configuration (e.g., the RRC configuration) indicating the second value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the common and/or shared PUCCH resource, and/or (iv) the UE not being configured with the CS-RNTI (e.g., the UE may not be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process). In some examples, the UE does not start the unicast retransmission timer <NUM> in response to determining not to start the unicast retransmission timer <NUM>. In some examples, the UE determines to start the unicast retransmission timer <NUM> (in response to expiry of the unicast RTT timer <NUM>, for example) based on (i) the feedback mode being ack-nack mode, (ii) the first configuration (e.g., the RRC configuration) indicating the first value, (iii) the HARQ feedback <NUM> (e.g., NACK) being transmitted via the dedicated and/or specific PUCCH resource, and/or (iv) the UE being configured with the CS-RNTI (e.g., the UE may be configured to use the CS-RNTI for detecting a retransmission associated with the first HARQ process). In some examples, the UE starts the unicast retransmission timer <NUM> in response to determining to start the unicast retransmission timer <NUM> (e.g., the unicast retransmission timer <NUM> is started in response to expiry of the unicast RTT timer <NUM>).

It may be appreciated that, in accordance with some embodiments herein, the UE may not waste power and/or resources monitoring a control channel (e.g., PDCCH) for a unicast retransmission of a multicast transmission (e.g., the first multicast transmission <NUM>) when the network (e.g., the gNB) is not scheduled to provide a unicast retransmission (e.g., any unicast retransmission) of the multicast transmission. Thus, the present disclosure provides for improved efficiency in comparison with some systems in which the UE may start (both) the unicast RTT timer <NUM> and the unicast retransmission timer <NUM> without considering the feedback mode, the first configuration, the type of resource used to send the HARQ feedback <NUM>, and/or whether the UE is configured with the CS-RNTI.

In some examples, one, some and/or all of the aforementioned instances of the term "C-RNTI" may be replaced by the term "CS-RNTI", such as in embodiments where a multicast transmission (e.g., the first multicast transmission <NUM>, the first multicast transmission <NUM>, the first multicast transmission <NUM>) is detected/received (and/or decoded) based on a configured (e.g., pre-configured) multicast resource, such as a configured (e.g., pre-configured) downlink multicast assignment.

In an example, in <FIG>, UE may keep monitoring (e.g., active monitoring) a control channel (e.g., PDCCH) for a unicast (e.g., C-RNTI) retransmission within the first period of time <NUM> (including the second period of time <NUM>) until detection of G-RNTI (re)transmission associated with the PDSCH/data/TB for the same HARQ process at time t5. Similar example in <FIG>, if no retransmission is detected by UE or scheduled by the network (e.g. according to network scheduling strategy, such as gNB scheduling strategy) and the length of unicast DRX retransmission timer is longer than groupcast/multicast DRX retransmission timer, UE may need to additionally/unnecessarily monitor control channel (e.g., PDCCH) within the third period of time <NUM>. For solving these problems, UE may (i) determine to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) if ack-nack mode is used (and/or indicated) for the multicast data/PDSCH/TB and/or (ii) determine not to start the unicast HARQ RTT Timer and/or not to start the unicast DRX Retransmission Timer if nack-only mode is used (and/or indicated) for the multicast data/PDSCH/TB (e.g., G-RNTI data/PDSCH/TB). UE may determine whether to start C-RNTI HARQ RTT Timer and/or DRX Retransmission Timer based on HARQ feedback mode (e.g. ack-nack mode or nack-only mode) used (and/or indicated and/or configured) for the multicast data/PDSCH/TB for the first HARQ process and/or based on a configurable configuration in RRC layer (and/or based on other information). In an example, in <FIG>, UE may determine not to start unicast HARQ RTT Timer at time t2 and/or not to start unicast DRX Retransmission Timer (responsive to, such as upon, unicast HARQ RTT Timer expiry, for example). In some examples, UE may (attempt to, for example) receive and/or decode the multicast data/PDSCH/TB based on a configured (e.g., pre-configured) multicast resource (e.g. a configured downlink multicast assignment). In some examples, the aforementioned C-RNTI may be replaced by CS-RNTI if the multicast data/PDSCH/TB is decoded and/or received based on a pre-configured multicast resource.

In some examples, UE may (i) determine to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) if NACK is sent on a dedicated (and/or specific) PUCCH (for the UE) and/or (ii) determine not to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) if NACK is sent on a common/shared PUCCH (for more than one UE). UE may determine whether to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) based on at least if PUCCH resource for sending NACK is common/shared/dedicated or not.

In some examples, UE may (i) determine to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) if CS-RNTI is configured/used to detect a retransmission for a multicast data/PDSCH/TB received on a pre-configured multicast resource and/or (ii) determine not to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) if CS-RNTI is not configured/used. UE may determine whether to start unicast HARQ RTT Timer (e.g., C-RNTI HARQ RTT Timer) and/or unicast DRX Retransmission Timer (e.g., C-RNTI DRX Retransmission Timer) based on whether CS-RNTI is configured (and/or used, such as for detecting a retransmission of a multicast data/PDSCH/TB received on a pre-configured multicast resource).

In some examples, one, some and/or all of the aforementioned instances of the term "multicast" may be replaced by the term "groupcast".

One, some and/or all of the foregoing examples, concepts, techniques and/or embodiments can be formed and/or combined to a new embodiment.

In some examples, embodiments disclosed herein may be implemented independently and/or separately. Alternatively and/or additionally, a combination of embodiments described herein may be implemented. Alternatively and/or additionally, a combination of embodiments described herein may be implemented concurrently and/or simultaneously.

Various techniques, embodiments, methods and/or alternatives of the present disclosure may be performed independently and/or separately from one another. Alternatively and/or additionally, various techniques, embodiments, methods and/or alternatives of the present disclosure may be combined and/or implemented using a single system. Alternatively and/or additionally, various techniques, embodiments, methods and/or alternatives of the present disclosure may be implemented concurrently and/or simultaneously.

To enhance 3GPP specification, such as <NPL>), for wireless communication in accordance with some embodiments herein, Enhancement <NUM> is provided herein. Enhancements <NUM> is reflective of implementation in accordance with some embodiments herein, and comprises modifications to 3GPP specification. According to some embodiments, at least a portion of Enhancement <NUM> may be implemented.

Enhancement <NUM> may be implemented according to one or more embodiments of the present disclosure. In Enhancement <NUM>, addition <NUM>, addition <NUM>, addition <NUM>, addition <NUM>, addition <NUM> and/or addition <NUM> are made to Section <NUM> of <NPL>). In some examples, embodiments of the present disclosure may be implemented via one or more of additions <NUM>-<NUM> in Enhancement <NUM>. To distinguish addition X (where X = <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) from what is originally included in Section <NUM> of <NPL>), addition X is in bold, and is preceded by the term "ADDITION X STARTS:" and followed by the term "ADDITION X ENDS".

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receives and/or detects a multicast transmission of downlink data on a configured downlink multicast resource, wherein the multicast transmission is associated with a HARQ process. In some examples, the multicast transmission (and/or the downlink data) is for the HARQ process. In some examples, the multicast transmission of the downlink data may be received and/or detected for (and/or in association with) the HARQ process. In some examples, the configured downlink multicast resource is a pre-configured downlink multicast resource (e.g., a downlink multicast resource with which the UE is configured prior to receiving and/or detecting the multicast transmission). In some examples, the configured downlink multicast resource may comprise a downlink multicast assignment. In step <NUM>, the UE starts a multicast HARQ RTT timer associated with the HARQ process. In some examples, the UE starts the multicast HARQ RTT timer in response to transmitting a negative HARQ feedback (e.g., NACK) for the multicast transmission (e.g., the UE may transmit the negative HARQ feedback in response to failing to decode the multicast transmission and/or the downlink data). In step <NUM>, the UE determines whether to start a unicast HARQ RTT timer associated with the HARQ process based on whether the UE is configured with a CS-RNTI. In some examples, the determination (in step <NUM>) of whether to start the unicast HARQ RTT timer is performed based upon other information in addition to whether the UE is configured with the CS-RNTI. In some examples, the CS-RNTI is used for detecting a transmission (e.g., a retransmission) of the downlink data associated with the HARQ process.

In some examples, the multicast transmission is transmitted by a network (e.g., a gNB).

In some examples, the multicast transmission comprises a new multicast transmission of the downlink data. In some examples, the new multicast transmission of the downlink data is not a retransmission of a prior multicast transmission by the network. In some examples, the new multicast transmission of the downlink data is not a retransmission of the downlink data (e.g., the new multicast transmission corresponds to an initial transmission of the downlink data by the network).

Preferably, the UE starts the unicast HARQ RTT timer based on the UE being configured with the CS-RNTI. For example, the UE may determine to start the unicast HARQ RTT timer if the UE is configured with the CS-RNTI (to be used for detecting a retransmission of the downlink data associated with the HARQ process, for example). Alternatively and/or additionally, the UE may determine to start the unicast HARQ RTT timer if the UE is configured to use the CS-RNTI for the HARQ process (e.g., the UE is configured to use the CS-RNTI for detecting a retransmission of the downlink data associated with the HARQ process). In some examples, the UE starts the unicast HARQ RTT timer concurrently with starting the multicast HARQ RTT timer. In some examples, a difference between a time at which the UE starts the unicast HARQ RTT timer and a time at which the UE starts the multicast HARQ RTT timer is at most a threshold difference.

Preferably, the UE does not start the unicast HARQ RTT timer based on the UE not being configured with the CS-RNTI. For example, the UE may determine not to start the unicast HARQ RTT timer if the UE is not configured with the CS-RNTI (to be used for detecting a retransmission of the downlink data associated with the HARQ process, for example) and/or if the UE is not configured to use the CS-RNTI for the HARQ process (e.g., the UE is not configured to use the CS-RNTI for detecting a retransmission of the downlink data associated with the HARQ process).

Preferably, the multicast HARQ RTT Timer is a drx-HARQ-RTT-TimerDL-PTM timer. In some examples, the drx-HARQ-RTT-TimerDL-PTM timer is associated with point-to-multipoint (PTM) communication.

Preferably, the unicast HARQ RTT timer is a drx-HARQ-RTT-TimerDL timer.

Preferably, the UE starts a unicast DRX retransmission timer associated with the HARQ process in response to (e.g., upon) expiry of the unicast HARQ RTT timer.

Preferably, the UE starts a multicast DRX retransmission timer associated with the HARQ process in response to (e.g., upon) expiry of the multicast HARQ RTT timer.

Preferably, the UE monitors PDCCH when the unicast DRX retransmission timer is running. For example, the UE is configured to perform PDCCH monitoring (e.g., monitoring for a unicast transmission on PDCCH) when the unicast DRX retransmission timer is running. For example, the UE monitors PDCCH for a unicast transmission (e.g., a unicast retransmission of the downlink data) when the unicast DRX retransmission timer is running.

Preferably, the UE monitors PDCCH when the multicast DRX retransmission timer is running. For example, the UE is configured to perform PDCCH monitoring (e.g., monitoring for a multicast transmission on PDCCH) when the multicast DRX retransmission timer is running. For example, the UE monitors PDCCH for a multicast transmission (e.g., a multicast retransmission of the downlink data) when the multicast DRX retransmission timer is running.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE, the device <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE (i) to receive and/or detect a multicast transmission of downlink data on a configured downlink multicast resource, wherein the multicast transmission is associated with a HARQ process, (ii) to start a multicast HARQ RTT timer associated with the HARQ process, and (iii) to determine whether to start a unicast HARQ RTT timer associated with the HARQ process based on whether the UE is configured with a CS-RNTI. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform one, some and/or all of the above-described actions and steps and/or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receives a configuration indicative of a feedback mode (e.g., HARQ feedback mode) for multicast transmission. In some examples, the configuration is indicative of the feedback mode to be used by the UE for receiving one or more multicast transmissions. In step <NUM>, the UE receives and/or detects a first multicast transmission of downlink data on a configured downlink multicast resource, wherein the first multicast transmission is associated with a HARQ process. In some examples, the first multicast transmission (and/or the downlink data) is for the HARQ process. In some examples, the first multicast transmission of the downlink data may be received and/or detected for (and/or in association with) the HARQ process. In some examples, the configured downlink multicast resource is a pre-configured downlink multicast resource (e.g., a downlink multicast resource with which the UE is configured prior to receiving and/or detecting the first multicast transmission). In some examples, the configured downlink multicast resource may comprise a downlink multicast assignment. In step <NUM>, the UE transmits a negative HARQ feedback (e.g., NACK) for the first multicast transmission. In some examples, the UE transmits the negative HARQ feedback in response to failing to decode the first multicast transmission and/or the downlink data. In some examples, the UE transmits the negative HARQ feedback to a sender of the first multicast transmission. In step <NUM>, the UE starts a multicast HARQ RTT timer associated with the HARQ process. In some examples, the UE starts the multicast HARQ RTT timer in response to transmitting the negative HARQ feedback for the first multicast transmission. In step <NUM>, the UE determines whether to start a unicast HARQ RTT timer associated with the HARQ process based on the feedback mode and whether the UE is configured with a CS-RNTI. In some examples, the determination (in step <NUM>) of whether to start the unicast HARQ RTT timer is performed based upon other information in addition to the feedback mode and whether the UE is configured with the CS-RNTI. In some examples, the CS-RNTI is used for detecting a transmission (e.g., a retransmission) of the downlink data associated with the HARQ process.

In some examples, the first multicast transmission is transmitted by a network (e.g., a gNB). In some examples, the UE transmits the negative HARQ feedback to the network.

In some examples, the first multicast transmission comprises a new multicast transmission of the downlink data. In some examples, the new multicast transmission of the downlink data is not a retransmission of a prior multicast transmission by the network. In some examples, the new multicast transmission of the downlink data is not a retransmission of the downlink data (e.g., the new multicast transmission corresponds to an initial transmission of the downlink data by the network).

In some examples, the feedback mode that is used by the UE (in step <NUM>) to determine whether to start the unicast HARQ RTT timer may be different than the feedback mode indicated by the configuration received by the UE.

In some examples, the configuration comprises a first indication that the feedback mode is a first feedback mode (e.g., ack-nack mode or nack-only mode). In some examples, after receiving the configuration, the feedback mode may be switched (by the UE, the network and/or another entity, for example) from the first feedback mode to a second feedback mode (e.g., the feedback mode may be switched from ack-nack mode to nack-only mode or from nack-only mode to ack-nack mode). After switching the feedback mode from the first feedback mode to the second feedback mode, the feedback mode used by the UE for multicast transmission may be different than the first indication of the feedback mode. In some examples, the feedback mode that is used by the UE (in step <NUM>) to determine whether to start the unicast HARQ RTT timer is the second feedback mode, which may be different than the first feedback mode indicated by the configuration received by the UE.

In some examples, the feedback mode that is used by the UE (in step <NUM>) to determine whether to start the unicast HARQ RTT timer may be the same as the feedback mode indicated by the configuration received by the UE.

Preferably, the UE starts the unicast HARQ RTT timer based on the UE being configured with the CS-RNTI and the feedback mode being ack-nack mode. For example, the UE may determine to start the unicast HARQ RTT timer if (i) the UE is configured with the CS-RNTI (to be used for detecting a retransmission of the downlink data associated with the HARQ process, for example) and/or the UE is configured to use the CS-RNTI for the HARQ process (e.g., the UE is configured to use the CS-RNTI for detecting a retransmission of the downlink data associated with the HARQ process), and (ii) the feedback mode is ack-nack mode. In some examples, the UE starts the unicast HARQ RTT timer concurrently with starting the multicast HARQ RTT timer. In some examples, a difference between a time at which the UE starts the unicast HARQ RTT timer and a time at which the UE starts the multicast HARQ RTT timer is at most a threshold difference.

Preferably, the UE does not start the unicast HARQ RTT timer based on at least one of (i) the UE not being configured with the CS-RNTI or (ii) the feedback mode being nack-only mode. For example, the UE may determine not to start the unicast HARQ RTT timer if at least one of (i) the UE is not configured with the CS-RNTI (to be used for detecting a retransmission of the downlink data associated with the HARQ process, for example) and/or the UE is not configured to use the CS-RNTI for the HARQ process (e.g., the UE is not configured to use the CS-RNTI for detecting a retransmission of the downlink data associated with the HARQ process), or (ii) the feedback mode is nack-only mode.

Preferably, the configuration is a harq-FeedbackOptionMulticast configuration.

In some examples, the configuration is indicative of the feedback mode to be used by the UE for receiving one or more multicast transmissions (comprising the first multicast transmission, for example) from the network and/or one or more other networks.

Preferably, the multicast HARQ RTT Timer is a drx-HARQ-RTT-TimerDL-PTM timer.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE, the device <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE (i) to receive a configuration indicative of a feedback mode for multicast transmission, (ii) to receive and/or detect a first multicast transmission of downlink data on a configured downlink multicast resource, wherein the first multicast transmission is associated with a HARQ process, (iii) to transmit a negative HARQ feedback for the first multicast transmission, (iv) to start a multicast HARQ RTT timer associated with the HARQ process, and (v) to determine whether to start a unicast HARQ RTT timer associated with the HARQ process based on the feedback mode and whether the UE is configured with a CS-RNTI. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform one, some and/or all of the above-described actions and steps and/or others described herein.

A communication device (e.g., a UE, a base station, a network node, etc.) may be provided, wherein the communication device may comprise a control circuit, a processor installed in the control circuit and/or a memory installed in the control circuit and coupled to the processor. The processor may be configured to execute a program code stored in the memory to perform method steps illustrated in <FIG>. Furthermore, the processor may execute the program code to perform one, some and/or all of the above-described actions and steps and/or others described herein.

A computer-readable medium may be provided. The computer-readable medium may be a non-transitory computer-readable medium. The computer-readable medium may comprise a flash memory device, a hard disk drive, a disc (e.g., a magnetic disc and/or an optical disc, such as at least one of a digital versatile disc (DVD), a compact disc (CD), etc.), and/or a memory semiconductor, such as at least one of static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), etc. The computer-readable medium may comprise processor-executable instructions, that when executed cause performance of one, some and/or all method steps illustrated in <FIG>, and/or one, some and/or all of the above-described actions and steps and/or others described herein.

It may be appreciated that applying one or more of the techniques presented herein may result in one or more benefits including, but not limited to, increased efficiency of communication between devices (e.g., a UE and/or a network). In some systems, if a network (e.g., gNB) would not schedule unicast retransmissions for a multicast data, but the UE may still try to receive unicast retransmissions since UE is still monitoring C-RNTI on PDCCH (e.g., monitoring for C-RNTI retransmission of the multicast data) due to a running unicast DRX retransmission timer. Using the embodiments provided herein, UE can save more power by reducing active time for C-RNTI monitoring on PDCCH.

Various aspects of the disclosure have been described above. It should be apparent that the teachings herein may 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 may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. As an example of some of the above concepts, in some aspects concurrent channels may be established based on pulse repetition frequencies. In some aspects concurrent channels may be established based on pulse position or offsets. In some aspects concurrent channels may be established based on time hopping sequences. In some aspects concurrent channels may be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

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

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

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 ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Alternatively and/or additionally, 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 disclosed subject matter has been described in connection with various aspects, it will be understood that the disclosed subject matter is capable of further modifications.

Claim 1:
A method of a User Equipment, in the following also referred to as UE, comprising:
being configured with a Group Configured Scheduling Radio Network Temporary Identifier, in the following also referred to as G-CS-RNTI, by a base station, wherein the G-CS-RNTI is used for Semi-Persistent Scheduling, in the following also referred to as SPS, activation associated with a configured downlink multicast resource;
at least one of receiving or detecting a first multicast transmission of downlink data on the configured downlink multicast resource, wherein the first multicast transmission is associated with a Hybrid Automatic Repeat Request, in the following also referred to as HARQ, process (<NUM>);
in response to receiving or detecting the first multicast transmission, starting a multicast HARQ Round Trip Time, in the following also referred to as RTT, timer associated with the HARQ process (<NUM>); and
characterized by
in response to receiving or detecting the first multicast transmission, determining whether to start a unicast HARQ RTT timer associated with the HARQ process based on whether the UE is configured with a Configured Scheduling Radio Network Temporary Identifier, in the following also referred to as CS-RNTI, (<NUM>).