Patent Description:
Relevant background art includes <NPL>, "<NPL>, and <NPL>.

A codeblock-group based retransmission scheme as claimed in the appended claims.

A network that includes both small cell and macro cells may be known as a heterogeneous network. The base stations <NUM> / UEs <NUM> may use spectrum up to Y MHz (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

The IP Services <NUM> may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service (PSS), and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), or some other suitable terminology without loss of generality. The base station <NUM> provides an access point to the EPC <NUM> for a UE <NUM>. Examples of UEs <NUM> include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a toaster, or any other similar functioning device. Some of the UEs <NUM> may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, etc.).

Referring again to <FIG>, in certain aspects, the UE <NUM> may be configured to determine that one or more codeblock groups (CBGs) of a set of CBGs received from a base station (e.g., base station <NUM>/<NUM>) failed to be properly decoded at the UE, send to the base station, ACK/NACK feedback indicating the one or more CBGs that failed to be properly decoded, and receive a retransmission of CBGs of the set of CBGs from the base station and information indicating the retransmitted CBGs of the set of CBGs (<NUM>). The base station <NUM>/<NUM> may be configured to receive, from the UE <NUM>, the ACK/NACK feedback indicating that a subset of CBGs (e.g., the one or more CBGs) failed to be properly decoded, determine which CBGs to retransmit based on the ACK/NACK feedback, retransmit the CBGs determined based on the ACK/NACK feedback, and transmit information indicating which CBGs are being retransmitted (<NUM>). In a particular example, each CBG of the set of CBGs received from the base station <NUM>/<NUM> may represent a portion of a larger transport block (TB), and the UE <NUM> may provide a CBG-level feedback, such as a bitmap or other suitable representation, of the particular CBGs of the TB which failed to decode. Based upon the feedback received, the base station <NUM>/<NUM> may determine which CBGs are needed and may send the CBGs to the UE <NUM> in a retransmission with portions of a new TB. The CBG-level retransmission and the portions of the new TB may occur in the same slot (of a subframe) while being managed under different HARQ process identifiers. The UE <NUM> may then determine which portions of the retransmission represent the retransmitted CBGs, verify that the failed CBGs have been properly received, decode the retransmitted CBGs and portions of the new TB, and continue with CBG-level feedback until decoding succeeds or the process is terminated. The techniques disclosed herein support low latency operations and the efficient use of air link resources.

<FIG> is a diagram <NUM> illustrating an example of a DL frame structure. <FIG> is a diagram <NUM> illustrating an example of channels within the DL frame structure. <FIG> is a diagram <NUM> illustrating an example of an UL frame structure. <FIG> is a diagram <NUM> illustrating an example of channels within the UL frame structure. A frame (<NUM>) may be divided into <NUM> equally sized subframes. Each subframe may include two consecutive time slots. A resource grid may be used to represent the two time slots, each time slot including one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)). For a normal cyclic prefix, an RB contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of <NUM> REs. For an extended cyclic prefix, an RB contains <NUM> consecutive subcarriers in the frequency domain and <NUM> consecutive symbols in the time domain, for a total of <NUM> REs.

As illustrated in <FIG>, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include cell-specific reference signals (CRS) (also sometimes called common RS), UE-specific reference signals (UE-RS), and channel state information reference signals (CSI-RS). <FIG> illustrates CRS for antenna ports <NUM>, <NUM>, <NUM>, and <NUM> (indicated as R<NUM>, R<NUM>, R<NUM>, and R<NUM>, respectively), UE-RS for antenna port <NUM> (indicated as R<NUM>), and CSI-RS for antenna port <NUM> (indicated as R). <FIG> illustrates an example of various channels within a DL subframe of a frame. The physical control format indicator channel (PCFICH) is within symbol <NUM> of slot <NUM>, and carries a control format indicator (CFI) that indicates whether the physical downlink control channel (PDCCH) occupies <NUM>, <NUM>, or <NUM> symbols (<FIG> illustrates a PDCCH that occupies <NUM> symbols). The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH may have <NUM>, <NUM>, or <NUM> RB pairs (<FIG> shows two RB pairs, each subset including one RB pair). The physical hybrid automatic repeat request (ARQ) (HARQ) indicator channel (PHICH) is also within symbol <NUM> of slot <NUM> and carries the HARQ indicator (HI) that indicates HARQ acknowledgement (ACK) / negative ACK (NACK) feedback based on the physical uplink shared channel (PUSCH). The primary synchronization channel (PSCH) may be within symbol <NUM> of slot <NUM> within subframes <NUM> and <NUM> of a frame. The PSCH carries a primary synchronization signal (PSS) that is used by a UE to determine subframe/symbol timing and a physical layer identity. The secondary synchronization channel (SSCH) may be within symbol <NUM> of slot <NUM> within subframes <NUM> and <NUM> of a frame. The SSCH carries a secondary synchronization signal (SSS) that is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSCH and SSCH to form a synchronization signal (SS) block. The MIB provides a number of RBs in the DL system bandwidth, a PHICH configuration, and a system frame number (SFN).

As illustrated in <FIG>, some of the REs carry demodulation reference signals (DM-RS) for channel estimation at the base station. The UE may additionally transmit sounding reference signals (SRS) in the last symbol of a subframe. <FIG> illustrates an example of various channels within an UL subframe of a frame. A physical random access channel (PRACH) may be within one or more subframes within a frame based on the PRACH configuration. The PRACH may include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. A physical uplink control channel (PUCCH) may be located on edges of the UL system bandwidth.

As described herein, controller/processor <NUM>/<NUM> supports HARQ operation at the CBG-level in which a device requests retranmission of a partial TB, e.g., one or more CBGs of a TB, and through which new data and retransmitted CBGs may form part of a same resource allocation.

LTE and NR systems supports many diverse applications that have stringent latency and/or reliability requirements such as the URLLC, and others such as the eMBB. URLLC and eMBB communications are transmitted based on different transmission durations. For example, eMBB transmissions may have longer duration, e.g., with slot based transmission, and URLLC transmissions may have shorter duration, e.g., with mini-slot based transmissions. In NR systems, for example, dynamic resource sharing between URLLC and eMBB may be supported, e.g., with an indicator channel. For example, a resource occupied by an ongoing eMBB communication may be punctured/preempted for a URLLC type transmission. In such a scenario, a device, e.g., a base station, may provide an indication of URLLC preemption/puncture to a UE which may be expecting eMBB type data on the punctured/preempted eMBB resource(s) regarding the impacted eMBB resource to facilitate the UE's demodulating and decoding of the current transmission and subsequent (re)-transmissions of the impacted eMBB data. With CBG level ACK/NACK feedback, the UE may indicate to the base station a failure to decode one or more transmitted CBGs and/or codeblocks (CBs). The approach is more flexible than pure TB-level feedback, enables a more efficient use of resources, and potentially reduces latency associated with the transmission and processing of duplicative information. For instance, user data and/or system information carried by a PDSCH may be coded in a set of CBs that may represent a TB. The PDSCH CBs in the TB may be collected/grouped into CBGs. Via the CBG level ACK/NACK feedback, the UE may indicate to the base station which of one or more CBGs have not been properly decoded, e.g., due to the impact of resource puncturing, noise and/or channel interference etc. In many such scenarios, CBG level ACK/NACK feedback may facilitate efficient recovery, by the UE, of CBs and/or CBGs failed in previous transmissions.

<FIG> is a drawing <NUM> illustrating signaling exchange between a base station <NUM> and a UE <NUM> in a communication system that supports dynamic resource sharing between URLLC and eMBB. As illustrated, there may be several rounds of handshake between the base station <NUM> and the UE <NUM>, e.g., when dynamic resource sharing between URLLC and eMBB type communication occurs and a eMBB resource is punctured/preempted for a URLLC type transmission. For example, consider that the base station <NUM> needs to send URLLC data while an eMBB communication is ongoing. As dynamic resource sharing between URLLC and eMBB is supported, the base station <NUM> may puncture/preempt one or more resources (e.g., time-frequency resources) on which eMBB data is coded, e.g., resources for CBGs corresponding to the eMBB communication. In an aspect, the base station <NUM> may send a puncturing/preemption indication (e.g., a URLLC indication) <NUM> to the UE <NUM> indicating the impacted/affected eMBB resources due to the resource puncturing, e.g., for URLLC data. Providing such a puncturing indication facilitates demodulating and decoding of a current transmission and subsequent (re)-transmission of the eMBB data, e.g., CBGs corresponding to the eMBB data, that was replaced by the URLLC data in the current transmission. Upon receiving the puncturing indication <NUM>, the UE <NUM> may determine that CBGs corresponding to the expected eMBB data on the indicated punctured eMBB resources may be corrupted and may not be decoded. While the UE may decode CBGs corresponding to the eMBB data on the non-impacted resources, the UE <NUM> may fail to properly decode CBGs on the impacted, e.g., punctured, eMBB resources. Thus the UE may null out the log-likelihood ratios (LLRs) corresponding to the data received on the impacted resources. Next, the UE <NUM> may send a multibit HARQ feedback, e.g., a multibit ACK/NACK feedback to the base station <NUM> indicating the CBGs which the UE failed to decode thereby allowing the base station <NUM> to determine which CBGs need to be retransmitted. Next, assuming that the base station <NUM> properly decodes the ACK/NACK feedback to determine which CBGs need to be retransmitted, the base station <NUM> may retransmit (<NUM>) the CBGs, which the UE <NUM> failed to decode in the previous transmission, to the UE <NUM>. The UE <NUM> may receive and decode the CBGs after successful reception.

While the retransmission mechanism facilitates recovery of CBs/CBGs which failed decoding in the previous transmission, it is noted that CBG retransmission may be limited to one TB per HARQ process. However, such a constraint on retransmission may lead to inefficient use of the resources in the retransmission slot and low throughput. While the retransmission of failed CBGs may occupy only a portion of available resources of a subframe slot being used for retransmission, many resources of the slot remain unoccupied. Since the retransmission may only allow retransmission of failed CBGs and not new or additional data, the throughput may be significantly affected due to wastage/non utilization of slot resources to transmit more new data.

From the above, it should be appreciated that methods to efficiently use the unoccupied resources in the retransmission slot to achieve a higher throughput are desirable. One approach may include assigning a subset of an RB allocation to a UE for CBG-level retransmission and scheduling another UE in the remaining portion of the RB allocation so as to utilize the entire resource. However, such a solution may depend on the availability of another active UE that may share the unoccupied resources and thus may not work when such an active UE is not available.

In accordance with an aspect of the disclosure, multiple HARQ processes per slot are utilized to facilitate efficient CBG-level HARQ operation. As discussed below, in accordance with this aspect, in addition to the retransmission of failed CBGs corresponding to a previous transmission which may be associated with a TB of a first HARQ process (having a first HARQ process identifier (ID)), additional data associated with another TB of a different HARQ process (having a second/different HARQ process ID) may be transmitted on unoccupied resources of the slot/subframe in which the failed CBGs are retransmitted. In some configurations, retransmission of CBGs corresponding to a first transport block associated with one HARQ process, e.g., having HARQ process ID X, is possible together with the transport block level or CBG level retransmission of one or more other HARQ processes which are different than the HARQ process having ID X.

<FIG> is a drawing <NUM> illustrating signaling exchange between a base station <NUM> and a UE <NUM> in a communication system in which various features of the proposed methods may be utilized such as, for example, use of multiple HARQ processes per slot. That is, in addition to retransmission of failed CBGs, a new TB with new/additional data of a separate/different HARQ process is transmitted, e.g., in the same slot/aggregated-slot or mini-slot. For discussion purposes, consider the same/similar example as discussed with regard to <FIG>. The base station <NUM> may need to send some low latency data while an eMBB communication is ongoing, e.g., eMBB data is being transmitted as an initial (first) transmission. As previously discussed, the base station <NUM> may puncture one or more eMBB resources to use for communicating URLLC data. The base station <NUM> may send a puncturing indication <NUM> to the UE <NUM> indicating the impacted/affected eMBB resources due to the resource puncturing for URLLC data. Upon receiving the puncturing indication <NUM>, the UE <NUM> may determine the affected eMBB resources which were punctured for URLLC data and may further determine one or more CBGs transmitted from the base station <NUM> on the impacted resources in the initial transmission. While the UE <NUM> may successfully decode CBGs corresponding to the eMBB data on the non-impacted resources (e.g., assuming no interference/noise affected the non-impacted eMBB resources), the same may not be true for one or more CBGs on the affected resources and the UE <NUM> may determine that one or more CBGs on the impacted eMBB resources could not be properly decoded, e.g., failed cyclic redundancy check (CRC). Accordingly, in some configurations, the UE <NUM> may null out the LLRs corresponding to the data received on the impacted resources. Also, the UE <NUM> may fail to decode other CBGs on other non-punctured resources as well, e.g., due to interference, noise etc., causing the decoding to fail. Thus, the UE <NUM> may determine that retransmission of the one or more CBGs, which could not be decoded, is needed. Accordingly, the UE <NUM> may send a ACK/NACK feedback <NUM> to the base station <NUM> indicating the CBGs which the UE failed to decode thereby allowing the base station <NUM> to determine which CBGs need to be retransmitted. The ACK/NACK feedback <NUM> may be a multibit bitmap with each bit corresponding to a CBG and indicating whether the corresponding CBG is decoded or failed decoding. For example, the initial/first transmission (not shown in the example) may include <NUM> CBGs and the UE <NUM> may fail to decode <NUM> CBGs. In this example, the ACK/NACK feedback <NUM> may be a CBG bitmap such as "<NUM>", where "<NUM>" may represent an ACK indicating that the corresponding CBG is successfully decoded while "<NUM>" represents a NACK indicating that the corresponding CBG failed decoding, e.g., by failing a CRC or some other criteria of checking. The most significant bit (MSB) of the CBG bitmap may correspond to the first CBG and the least SB may correspond to the last CBG.

Next, assuming that the base station <NUM> properly decodes the ACK/NACK feedback <NUM> from the UE <NUM> to determine which CBGs need to be retransmitted, the base station <NUM> may retransmit the failed CBGs, which the UE <NUM> failed to decode in the previous transmission, in a retransmission <NUM>. However, in accordance with an aspect, along with the retransmitted CBGs, an additional transport block of new data may also be transmitted to the UE <NUM>. The additional transport block may include codeblocks or CBGs corresponding to new data that was not in the initial (previous) transmission. In some configurations, the retransmitted CBGs are retransmitted in a subframe along with the a transport block of new/additional data. For example, the CBGs may be retransmitted in a first mini-slot associated with a first set of symbols in the subframe while the new data is transmitted in a second mini-slot corresponding to a second set of symbols in the same subframe. In some configurations, the first set of symbols and the second set of symbols are different, e.g., in terms of time. For example, the first set of symbols may be earlier in time than the second set of symbols and thus while being transmitted in the same subframe, the retransmission of the CBGs may be before the transmission of the transport block of new data. Such a division of resources between the transport block including retransmitted CBGs and the transport block of new data may be referred to as a vertical division, e.g., time division multiplexing (TDM) within one slot. However, in some other configurations, the first set of symbols and the second set of symbols are the same and the separation of the resources used for the CBG retransmission and the data is in terms of subcarriers/frequency. Such a division of resources between the CBG retransmission and transmission of new data may be referred to as a horizontal division, e.g., frequency division multiplexing (FDM) over the original set of resources/resource blocks.

In accordance with one aspect of some configurations, the base station <NUM> may send downlink control information (DCI) <NUM> to the UE <NUM> to facilitate decoding and demodulation of the retransmitted CBGs and the new data. For example, in some configurations, the base station <NUM> may send the DCI including information indicating the subset of CBGs that are being retransmitted to allow the UE <NUM> to determine, e.g., even prior to decoding the retransmitted CBGs received by the UE <NUM>, whether the base station <NUM> sent the same CBGs which were identified by the UE <NUM> in the feedback <NUM>, e.g., CBGs which failed decoding in the previous transmission. It may be possible that the base station <NUM> may not have correctly decoded the ACK/NACK feedback <NUM> from the UE <NUM> and thus may have retransmitted different CBGs than what were requested by the UE <NUM>. In some configurations, the information in DCI <NUM> indicating the CBGs that are being retransmitted by the base station <NUM> may be in the form of a CBG bitmap or CBG mask where one or more bits of the bitmap/mask indicate which CBGs are retransmitted. The bitmap or CBG mask in the DCI <NUM> for the retransmitted CBGs may be based on the ACK/NACK feedback <NUM> from the UE <NUM>.

In some configurations, for simplicity, mixing up to <NUM> HARQ processes, e.g., one associated with retransmitted CBGs and the other associated with TB of the new data, is used. Via the DCI <NUM>, the base station <NUM> may inform the UE <NUM> which TB and/or set of CBGs is associated with which HARQ process ID and how the resources in the subframe are allocated between the CBGs being retransmitted and the TB of the new data. In frequency domain, the resource allocation may be common for both CBG retransmission and the transmission of the TB corresponding to the new data, while in time domain the two may occupy different resources, e.g., different mini-slots. In some configurations, the CBG retransmission and the TB (corresponding to the new data) transmission of separate HARQ processes are mini-slot based. Thus, the base station <NUM> may need to inform the UE <NUM> how the CBG retransmissions and the other TB corresponding to the new data are communicated in the subframe, e.g., by indicating slot/mini-slot boundaries between the two if the separation is in time domain. For example, if the retransmitted CBGs and the TB of the new data is in a slot of a subframe, the first set of OFDM symbols of the slot may be used for the retransmitted CBGs while the another set of OFDM symbols of the slot may be used for the TB of the new data, where the first set of OFDM symbols may be considered to correspond to a first mini-slot and the second set of OFDM symbols may correspond to a second mini-slot. Thus, in some configurations the DCI <NUM> may indicate a slot/mini-slot boundary between the retransmitted CBGs associated with the first TB and new data associated with a second TB. In some configurations, the DCI <NUM> may further include information indicating a modulation and coding scheme (MCS) associated with the transmitted new data.

Referring to UE <NUM>, using the received DCI <NUM>, the UE <NUM> may determine if the requested CBGs are retransmitted, and proceed to decode the received retransmitted CBGs if the retransmission is correct, e.g., if the retransmission carries the CBGs that failed decoding at the UE <NUM>. The CBG retransmission could be based on a special MCS, e.g., implicit MCS which may be derived by the UE <NUM> based on the knowledge of number of resources allocated for CBG retransmission and the number of CBGs that are retransmitted. Thus, in some configurations, the base station <NUM> may not explicitly indicate the MCS for the retransmitted CBGs and such information may rather be implicit. The UE <NUM> may be aware of the resource allocations for retransmission of the CBGs, e.g., based on previous grant/scheduling information communicated from the base station <NUM>, and may determine the number of CBGs being retransmitted, e.g., from the information indicating the CBGs being retransmitted which may be explicitly indicated in the DCI <NUM> or implicitly conveyed, for example, in CRC bits. However, if based on the received DCI <NUM> the UE <NUM> determines that the requested CBGs are not in the received retransmission, the UE <NUM> may decide not to process, e.g., decode, the received CBGs and may again request retransmission, e.g., by sending a CBG level NACK, of the CBGs. Also, if some requested CBGs are retransmitted but one or more of the requested CBGs are missing in the retransmission, the UE <NUM> may send another CBG level NACK, e.g., indicating one or more CBGs that still need to be retransmitted from the base station <NUM>.

In some configurations, the CBG identity for retransmission may be signaled explicitly or implicitly. Consider that the UE <NUM> requests (via the feedback <NUM> in the uplink) retransmission of a subset of CBGs out of a set of CBGs received in an initial transmission. The CBG retransmission list at the base station <NUM> may be different from those requested by the UE <NUM>, e.g., due to error(s) at the base station <NUM> and/or due to incorrect decoding by the base station <NUM> of the feedback <NUM> from the UE <NUM>. In order to ensure that the base station <NUM> and UE <NUM> are aligned (e.g., in terms of which CBGs need to be retransmitted), two configurations are proposed. In a first configuration, explicit signaling may be used where a list of retransmitted CBGs may be added in the DCI <NUM>. For example, the list may be in the form of a bitmap as discussed above. Upon receiving the DCI <NUM>, UE <NUM> may be able to determine if the correct CBGs are retransmitted or not. If some CBGs are not correctly retransmitted, the UE <NUM> may send another ACK/NACK feedback to trigger another retransmission. In a second configuration, implicit signaling may be utilized. For example, when sending the DCI <NUM>, the CBG bitmap at the base station <NUM> may be included in the CRC generation. For example, while generating the CRC bits for the control payload, e.g., the payload of the DCI <NUM> for one or more CBGs being retransmitted, the CBG bitmap may be appended to the bits of the payload of the DCI <NUM> being input to a CRC generation component/module. The resulting CRC bits generated by the CRC generation component may thus implicitly indicate the CBG bitmap as well. In some other configurations, the CBG bitmap may be used to scramble the CRC bits. Thus, the CBG bitmap and/or information indicating the CBGs being retransmitted may be explicitly or implicitly conveyed in many ways. On the UE <NUM> side, the UE <NUM> may use the CRC bits when performing the CRC check upon decoding the DCI <NUM> and if the CRC fails the UE <NUM> may know that retransmitted CBGs are not the same as requested (e.g., via the feedback <NUM>). In the implicit signaling approach, the DCI information overhead is significantly reduced compared to the explicit signaling case.

In accordance with another aspect, MIMO configuration may be used. In the case of MIMO, transmission of up to <NUM> transport blocks (TBs) associated with the same HARQ process is possible. That is, the two TBs being transmitted may share the same number of time-frequency resources and be associated with the same HARQ process but the TBs are still orthogonal in the spatial domain. Thus, in MIMO configurations, rather than starting with a single TB for a given HARQ process, a base station may start an initial transmission with <NUM> TBs associated with the same HARQ process in a MIMO fashion. For example, in an initial transmission, the base station may start with <NUM> TBs (e.g., TB0, TB1) associated with a same first HARQ process (e.g., HARQ ID=X) in a MIMO fashion, e.g., with a first MIMO transmission of <NUM> spatially separate streams carrying the <NUM> TBs, for example, a first stream carrying CBGs corresponding to TB0 and a second stream carrying CBGs corresponding to TB1. At the receiving UE, the UE may fail to decode some CBGs corresponding to each of the <NUM> TBs and request retransmission of the CBGs that failed decoding. In such a case, with MIMO configuration, the base station may retransmit the failed CBGs corresponding to the <NUM> TBs (associated with HARQ ID=X) with another one or more new/additional TBs (e.g., TB2, TB3) for new/additional data in a MIMO fashion, where the one or more new/additional TBs may be associated with a (same) second HARQ process (e.g., HARQ ID=Y) different than the first HARQ process. For example, the failed subset of CBGs corresponding to the <NUM> TBs may be transmitted via a second MIMO transmission that may also include the CBGs of TB2 and TB3. In a manner similar to what was discussed earlier with respect to <FIG>, the allocation between the CBGs of the first <NUM> TBs and the new TBs may be at a mini-slot level. However, for the first two TBs (TB0, TB1), a different number of CBGs may need to be retransmitted for each TB, e.g., one of the TBs might need a larger number of CBGs to be retransmitted than the other TB. For example, <NUM> CBGs corresponding to TB0 may need retransmission while <NUM> CBGs corresponding to TB1 may need retransmission. Thus, there may be a disparity in the resources that may be needed for the retransmission of the CBGs corresponding to TB0 and TB1. In such a case, in accordance with the features of the present disclosure the resources for both the TBs may still be aligned. For example, in an aspect if TB0 retransmission needs a smaller number of resources, the resources allocated to the TB0 retransmission may be modified to be the same size as the resources allocated for TB1 CBG retransmission, thereby removing the disparity and allowing MIMO configuration to be utilized for retransmission as well. In some configurations, the resources allocated for retransmission of CBGs corresponding to the initial TBs are equalized by modifying the MCS so that a consistent partition is used in the retransmission.

In one configuration, a transmitter, e.g., a base station, may use MIMO for an initial transmission of a set of CBGs, where the set of CBGs may correspond to a first TB and a second TB (e.g., TB0, TB1) and are transmitted with the same HARQ process ID (e.g., associated with a first HARQ process) via a first MIMO transmission. Assuming that a subset of CBGs fail decoding at a receiver, e.g., a UE, the UE may provide a ACK/NACK feedback in response to the first MIMO transmission. The base station may then retransmit the subset of CBGs (associated with the first HARQ process) via a second MIMO transmission in a subframe along with one or more TBs corresponding to new data associated with a different (e.g., second) HARQ process.

Various aspects related to Multi-HARQ ACK/NACK feedback design are also disclosed. In an aspect, additional signaling may be introduced to distinguish between CBG-level ACK/NACK and TB-level feedback. For discussion purposes, consider that along with retransmission of a first TB (e.g., TB0) including some CBGs which a UE (e.g., UE <NUM>) failed to decode in a first transmission, a second TB (e.g., TB1) corresponding to new data is transmitted. The first TB and the second TB may be associated with different HARQ processes. In accordance with an aspect, a multi-HARQ ACK/NACK feedback is supported via which TB level and/or CBG level ACK/NACK may be provided to the base station <NUM> for the different transmitted/retransmitted CBGs and/or corresponding TBs (associated with different HARQ processes). In an aspect, if at the receiving UE, the second TB (corresponding to the new/additional data) passes decoding, but if one or more retransmitted CBGs in the first TB are not properly decoded, the UE may signal that CBG retransmission of the first TB is needed while also acknowledging receipt of the second TB. That is, the UE <NUM> may send an ACK/NACK again to request retransmission of the failed CBGs corresponding to the first TB while indicating readiness for a third TB in the subsequent transmission. Likewise, if one or more CBGs of the second TB fail decoding, in order for the UE <NUM> to request CBG retransmission for failed CBGs of the second TB, the UE <NUM> may need to send ACK/NACK feedback. In accordance with one aspect of a combined CBG-level and TB-level HARQ operation, the feedback may include: a set of bits for a CBG level ACK/NACK indication corresponding to CBGs of one TB; <NUM>-bit for TB level ACK/NACK; and <NUM>-bit to indicate which TB is doing CBG level ACK/NACK (e.g., to which TB the CBG level ACK/NACK corresponds). In one configuration, if the receiver (e.g., UE) and the transmitter (e.g., base station) coordinate an order of the feedback based on an order of decoding the TBs, the <NUM>-bit to indicate which TB is doing CBG ACK/NACK may be avoided.

In a worst case scenario, retransmitted CBGs of TB0 and the second TB (TB1) both fail. While CBG retransmission for both TBs may be performed, the complexity may be high. For example, if after the retransmission of CBGs in TB0 along with the transmission of TB1, the UE <NUM> fails to decode some CBGs in both TBs (e.g., some CBGs of both TB0 and TB1), then the UE <NUM> may need to inform the base station which CBGs corresponding to each of the different TBs (TB0 and TB1) failed. In this case, the UE <NUM> may need to send two CBG-level indications (e.g., bitmaps) in the ACK/NACK feedback. However, sending two such bitmaps requires a large number of bits which increases the uplink control signaling overhead and complexity. While the additional feedback incurred by multiple CBG-level indications may be acceptable in some configurations, since the overall complexity and uplink signaling overhead is increased in this approach, sending such feedback may not be desirable in many cases. Alternatively, in such a scenario, in accordance with one aspect, the UE <NUM> may select one of the TBs for which retransmission of CBGs may be requested and ignore the other TB to avoid signaling overhead and complexity. In such a case, the UE <NUM> may be configured to send a feedback with: <NUM>-bit TB level NACK for one of the TBs (e.g., TB0), a set of bits for the other TB (CBG level ACK/NACK, e.g., a bitmap for the failed CBGs for the other TB (e.g., TB1), and <NUM>-bit to indicate/identify which TB is doing the CBG level ACK/NACK. The <NUM>-bit TB level NACK for the chosen TB may simply indicate that the UE failed to decode the given TB. This allows reduced overhead in uplink signaling for the feedback.

In a further aspect, features related to CBG granularity design are disclosed. In some configurations, an adaptive CBG granularity may be utilized where the CBG size is based on MCS and/or transport block size. In some configurations, there may be no fixed grouping of <NUM> or <NUM> CBs per CBG per configuration, but the CBG size may be transport block size dependent. The mapping could be deterministic, or semi-statically configured based on CBG configuration. For example, the CBG size may be dependent on the number of CBs. In some other configurations, CBG size may be more dynamic and may be dependent on number of CBG failures in a previous transmission. In particular, the number of CBs in each CBG could be different in a first (e.g., initial) transmission and the re-transmissions. For example, the number of CBs in each CBG of TB0 in an initial transmission from the base station <NUM> to the UE <NUM> may be different than the number of CBs in each retransmitted CBG in TB0 in a retransmission.

<FIG> illustrates a drawing <NUM> showing an example of signaling exchange between a base station <NUM> and a UE <NUM> of a communication system in which various features of the proposed methods may be used. The base station <NUM> may send an initial transmission <NUM> with <NUM> CBGs, e.g., a first TB may include <NUM> CBGs. Consider that the UE <NUM> fails to decode <NUM> CBGs of the initial transmission. For example, the UE <NUM> may determine that <NUM> CBGs out of <NUM> failed a CRC check. The UE <NUM> may send an ACK/NACK feedback <NUM> including a CBG mask/bitmap to ACK/NACK the decoded CBGs indicating which CBGs were successfully decoded and which failed decoding. The indication for failed CBGs may also convey that the UE <NUM> needs the failed CBGs to be retransmitted. In the illustrated example, the CBG bitmap is shown as "<NUM>" where <NUM> in the CBG bitmap indicates that the corresponding CBG is successfully decoded and <NUM> indicates that the corresponding CBG is not decoded and need to be retransmitted. Assuming that the base station <NUM> properly decodes the feedback <NUM>, the base station <NUM> may determine from the CBG bitmap "<NUM>" that the <NUM>th <NUM>th, <NUM>th and the <NUM>th CBGs are not properly decoded and need to be retransmitted. Accordingly, the base station <NUM> may send a retransmission <NUM> with <NUM> CBGs. In accordance with an aspect, the base station <NUM> may also send downlink control information <NUM> including, e.g., a CBG mask/bitmap "<NUM>", to indicate which CBGs are retransmitted, to ensure that the base station <NUM> and UE <NUM> are in agreement and aligned. The CBG mask/bitmap may be sent to the UE <NUM> as downlink control information. In some configurations, in addition to the retransmission of the <NUM> failed CBGs which may be associated with a first TB (e.g., TB0) associated with a first HARQ process (e.g., having a HARQ process ID = X), additional data associated with another TB (e.g., TB1) of a different HARQ process (e.g., having a second HARQ process ID = Y) may be transmitted on other unoccupied resources of the subframe in which the <NUM> failed CBGs are retransmitted. Upon receiving the CBG bitmap from the base station <NUM>, the UE <NUM> may compare the CBG bitmap sent in the ACK/NACK feedback <NUM> with the received CBG bitmap in <NUM>. In the example, since the two bitmaps match, the UE <NUM> may determine that correct CBGs have been retransmitted and proceeds to decode the CBGs. Upon successful/unsuccessful decoding, the UE <NUM> may send an ACK/NACK <NUM> to the base station <NUM>. In some configurations, where an additional TB (e.g., TB1) corresponding to new/additional data is received along with the TB (e.g., TB0) including the retransmitted CBGs, the ACK/NACK <NUM> may be a multi-HARQ ACK/NACK feedback including a TB or CBG level ACK/NACK for the data in TB0 and a TB or CBG level ACK/NACK for the data in TB1. For example, the UE <NUM> may send ACK/NACK feedback <NUM> including a single bit indicating an ACK or NACK for one TB (e.g., a TB level ACK/NACK for TB0), and a set of bits providing CBG level ACK/NACK indication for CBGs of the other TB (e.g., a CBG level ACK/NACK for TB1 indicating which CBGs of TB1 successfully decoded and which ones failed decoding). In another example, the UE <NUM> may include a CBG level ACK/NACK for TB0 and a TB level ACK/NACK for TB1. In addition, in case of the multi-HARQ ACK/NACK feedback, the feedback <NUM> may further include <NUM>-bit to indicate which TB (e.g., TB0 or TB1) is doing CBG level ACK/NACK.

<FIG> illustrates a drawing <NUM> showing another example of signaling exchange between the base station <NUM> and the UE <NUM> in a communication system in which various features of the proposed methods may be utilized. The example illustrates a scenario where an error occurs at the base station while decoding ACK/NACK feedback. In this example, the base station <NUM> may send an initial transmission <NUM> with <NUM> CBGs, e.g., a first TB may include <NUM> CBGs. Consider that the UE <NUM> fails to decode <NUM> CBGs of the initial transmission. The UE <NUM> may send an ACK/NACK feedback <NUM> including a CBG mask/bitmap to ACK/NACK the decoded CBGs indicating which CBGs were successfully decoded and which failed decoding. As discussed earlier, the indication for failed CBGs may also convey that the UE <NUM> needs the failed CBGs to be retransmitted. Similar to <FIG> example, for discussion purposes it may be considered that the CBG bitmap in the ACK/NACK feedback <NUM> is "<NUM>" where <NUM> indicates that the corresponding CBG is successfully decoded and <NUM> indicates that the corresponding CBG is not successfully decoded and need to be retransmitted. The base station <NUM> may receive the feedback <NUM> and may attempt to decode the feedback <NUM>. For purposes of this example, consider that a decoding error occurs causing improper decoding of the feedback <NUM> at the base station <NUM> and/or somehow the decoded CBG bitmap is corrupted. Thus, rather than the actual CBG bitmap "<NUM>", the base station <NUM> recovers a bitmap, e.g., "<NUM>" and thus incorrectly determines that the <NUM>th, <NUM>th, and <NUM>th CBGs are not properly decoded by the UE <NUM> and need to be retransmitted. Accordingly, based on the determined CBG bitmap the base station <NUM> may send a retransmission <NUM> with <NUM> CBGs. The base station <NUM> may further send a DCI <NUM> including a CBG mask/bitmap "<NUM>" to indicate the CBGs that are retransmitted. As discussed above, in some configurations, in addition to the retransmission of the failed CBGs which may be associated with a first TB (e.g., TB0) associated with a first HARQ process (e.g., HARQ process ID = X), another TB (e.g., TB1) of additional/new data associated with a different HARQ process (e.g., HARQ process ID = Y) may be transmitted on other unoccupied resources of the same subframe in which one or more CBGs are retransmitted. For discussion purposes, consider that in addition to the retransmission of the <NUM> CBGs in a first transport block TB0, a second TB (TB1) corresponding to new/additional data is also transmitted in the same subframe/slot that carries the retransmission <NUM>.

Upon receiving the CBG bitmap from the base station <NUM>, the UE <NUM> may compare the bitmap sent in the ACK/NACK feedback <NUM> with the received CBG bitmap in DCI <NUM>. In the example, since the two CBG bitmaps are different, the comparison fails and thus the UE <NUM> may determine that some of the requested CBGs have not been retransmitted and another CBG level indication may be needed to request retransmission, e.g., retransmission of the <NUM>th and the <NUM>th CBGs in the illustrated example. Furthermore, assuming that TB1 (second TB) corresponding to new/additional data is also transmitted by the base station <NUM> and received by the UE <NUM> along with the retransmission <NUM> (e.g., in the same subframe), the UE <NUM> may attempt to decode TB1. As discussed earlier, in such a case TB0 and TB1 are associated with different HARQ processes. In accordance with an aspect, the UE <NUM> may then send a multi-HARQ ACK/NACK feedback <NUM> including a CBG mask/bitmap "<NUM>" to the base station <NUM>, e.g., indicating the <NUM> CBGs (e.g., the <NUM>th and the <NUM>th CBGs in the example) that still need to be retransmitted. Additionally, depending on whether or not TB1 is successfully decoded, the ACK/NACK feedback <NUM> may further include, e.g., a TB level ACK/NACK indication for TB1. For example, if TB1 is decoded successfully, a TB level ACK may be included as part of the multi-HARQ ACK/NACK feedback <NUM>, in addition to the CBG level feedback (e.g., the CBG mask) for the failed CBGs of TB0. If some of the CBGs of TB1 fail decoding, then in some configurations, a TB level NACK may be sent, e.g., as part of the ACK/NACK feedback <NUM>. In addition, the ACK/NACK feedback <NUM> may further include at least one bit to indicate which TB (e.g., TB0 or TB1) is doing CBG level ACK/NACK. In some configurations, in the cases where a CBG level ACK/NACK feedback is needed for the retransmitted CBGs, a TB level ACK/NACK for TB1 corresponding to the new data rather than a CBG level ACK/NACK feedback may be used in some configurations (as in the above example) to avoid added complexity and extra bits overhead which would otherwise be incurred if a CBG level feedback were to be provided for TB1. However, in some configurations, a CBG level ACK/NACK (e.g., a CBG bitmap) may be provided for TB1 corresponding to the new data. For example, in one case the UE <NUM> may receive and successfully decode the retransmitted CBGs of the first TB (TB0) while one or more CBGs of the new data in the second TB (TB1) may fail decoding. In such a case, the UE <NUM> may send a feedback including a TB level ACK for the first TB (TB0) and a CBG level ACK/NACK for the second TB (TB1).

On the base station side, the base station <NUM> may receive the feedback <NUM> and attempt to decode the received information. Unlike the first time with feedback <NUM>, in the second instance, assuming that the base station <NUM> successfully decodes the feedback <NUM>, the base station <NUM> may determine from the CBG bitmap "<NUM>" that the <NUM>th and the <NUM>th CBGs need to be retransmitted. Accordingly, the base station <NUM> may send a second retransmission <NUM> including <NUM> CBGs, e.g., the <NUM>th and the <NUM>th CBGs. The base station <NUM> may also send downlink control information <NUM> including a CBG mask/bitmap "<NUM>" to indicate which CBGs are retransmitted. Upon receipt of the downlink control information <NUM>, the UE <NUM> may once again perform a CBG bitmap comparison to determine if correct CBGs are retransmitted (e.g., by comparing CBG bitmap of feedback <NUM> and the received CBG bitmap of downlink control information <NUM>. Considering that the bitmaps match in this example, the comparison performed by the UE <NUM> may indicate a pass and the UE <NUM> may proceed to decode the retransmitted CBGs received in the second retransmission <NUM>. Upon successful decoding, the UE <NUM> may send an ACK <NUM> to the base station <NUM> to acknowledge successful decoding of the retransmitted CBGs received in the second retransmission <NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method of flowchart <NUM> may be performed by a base station (e.g., the base station <NUM>/<NUM>/<NUM>). At <NUM>, the base station may transmit a set of CBGs to a UE e.g., as part of an initial transmission. For example, with reference to <FIG>, the base station may transmit a set of CBGs as part of an initial transmission <NUM> to the UE <NUM>. In one configuration, the set of CBGs may be part of a transport block/codeword of a DL PDSCH, e.g., where DL PDSCH codeblocks in the transport block are grouped into CBGs. At <NUM>, the base station may receive, from the UE, an ACK/NACK feedback indicating that a subset of CBGs of the set of transmitted CBGs failed to be decoded. For example, referring to <FIG>, the base station <NUM> may receive an ACK/NACK feedback <NUM> from the UE <NUM> including information indicating the CBGs that were not properly decoded at the UE <NUM>. For example, the information indicating which CBGs have not been properly decoded may be in the form of a CBG bitmap.

At <NUM>, the base station may retransmit, based on the received ACK/NACK feedback, the subset of CBGs. For example, again referring to <FIG>, the base station <NUM> may decode the ACK/NACK feedback <NUM> from the UE <NUM> and determine which CBGs need to be retransmitted based on the CBG mask/bitmap included in the feedback. Following the determination of the CBGs that need to be retransmitted, the base station <NUM> may retransmit the requested CBGs (in retransmission <NUM>). As discussed earlier with respect to <FIG>, in some configurations, in addition to the retransmission of CBGs in a TB, the base station <NUM> may also transmit a new TB of new/additional data, e.g., data that is not a retransmission. In some configurations, the retransmitted subset of CBGs and the TB of new/additional data may be transmitted in the same subframe. Accordingly, in some configurations as part of the operation at <NUM> of transmitting a TB including the subset of retransmitted CBGs in a subframe, at <NUM> the base station may also transmit at least a portion of another TB corresponding to new data to the UE in the same subframe. In some configurations, the subset of CBGs being retransmitted corresponds to a first TB associated with a first HARQ process and the other TB (e.g., second TB) of new/additional data may be associated with a second HARQ process different than the first HARQ process. In some such configurations, the first TB and the second TB may be within a same slot of the subframe.

In some configurations, the first TB may be associated with a first HARQ process and the second TB may be associated with a second HARQ process different than the first HARQ process. In some configurations, the subset of CBGs may be retransmitted in a first mini-slot corresponding to a first set of symbols in the subframe, and the portion of the second TB may be transmitted in a second mini-slot corresponding to a second set of symbols in the subframe. In some configurations, the first set of symbols and the second set of symbols may be different. In some configurations, the first set of symbols may be earlier in time than the second set of symbols. In some other configurations, the first set of symbols and the second set of symbols may be the same. In some configurations, the subset of CBGs may be retransmitted in a first set of resource blocks of the subframe, and the new data may be transmitted in a second set of resource blocks of the subframe, where the first set of resource blocks may be different than the second set of resource blocks.

At <NUM>, the base station may transmit information indicating the subset of CBGs that are being retransmitted. For example, referring to <FIG>, the base station <NUM> may transmit DCI <NUM> that includes a CBG bitmap indicating the CBGs that are being retransmitted. Similarly, with reference to <FIG>, the base station <NUM> may transmit the CBG mask/bitmap "<NUM>" indicating the retransmitted CBGs.

In some configurations, the information indicating the subset of CBGs that are being retransmitted may include a CBG level bitmap that indicates which CBGs are being retransmitted. For example, with reference to <FIG>, the information indicating the subset of CBGs being retransmitted may be the CBG mask/CBG bitmap <NUM> indicating that the <NUM>th, <NUM>th, <NUM>th and the <NUM>th CBGs are retransmitted. In some configurations, the information indicating the subset of CBGs that are being retransmitted may be transmitted in a DCI message. In some configurations, the DCI message may further indicate at least one of a slot boundary between the first TB corresponding to the retransmitted subset of CBGs and the second TB corresponding to the new data, or a modulation and coding scheme associated with the transmitted new data. In some configurations, the information indicating the subset of CBGs that are being retransmitted is explicitly indicated in the DCI message. In some configurations, the information indicating the subset of CBGs that are being retransmitted is implicitly indicated within cyclic redundancy check (CRC), e.g., with the CBG bitmap being included in the CRC bits.

Based on the DCI message, the receiving UE may determine whether the correct CBGs have been retransmitted. For example, if the DCI includes a CBG bitmap indicating the retransmitted CBGs, the UE may check the received CBG bitmap against the CBG bitmap included in the ACK/NACK feedback sent by the UE to the base station. The UE may then proceed to decode the retransmitted CBGs, e.g., when the correct subset of CBGs have been retransmitted. Assuming that a second TB corresponding to new/additional data is transmitted by the base station along with the first TB including the retransmitted subset of CBGs, the UE may also attempt to decode the CBGs of the second TB. Based on successful/unsuccessful decoding at the UE, at <NUM> the base station may receive an ACK/NACK (e.g., such as ACK/NACK <NUM> of <FIG>) from the UE. The received ACK/NACK may be a multi-HARQ ACK/NACK feedback including feedback regarding both the first and second TBs (assuming the second TB of new data was also transmitted at <NUM>). For example, the multi-HARQ ACK/NACK feedback may include a TB or CBG level ACK/NACK for the data in the first TB0, and a TB or CBG level ACK/NACK for the data in the second TB. The multi-HARQ ACK/NACK may be a multibit feedback including, for example, a single bit indicating an ACK or NACK for one TB (e.g., a TB level ACK/NACK for the first or second TB), and a set of bits providing CBG level ACK/NACK indication for CBGs of the other TB (e.g., a CBG level ACK/NACK for the other one of the first or second TB). Furthermore, in some configurations, the multi-HARQ ACK/NACK feedback may further include <NUM>-bit to indicate which TB (e.g., the first TB or the second TB) is doing CBG level ACK/NACK.

In one particular MIMO configuration, the set of CBGs (e.g. transmitted at <NUM>) corresponds to a first TB and a second TB transmitted via a first MIMO transmission, where the first TB and the second TB may be associated with a first HARQ process, and the ACK/NACK feedback (e.g., received at <NUM>) may be received in response to the first MIMO transmission. In such a MIMO configuration, the subset of CBGs is associated with the first HARQ process and is retransmitted via a second MIMO transmission in a subframe along with one or more TBs corresponding to new data associated with a second HARQ process.

In some configurations, the size of a CBG (e.g., a CBG of the set of CBGs/ subset of CBGs being retransmitted) may be configurable based on a size of a transport block to which the CBG corresponds. In some configurations, a number of codeblocks in each CBG of the set of transmitted CBGs is different than a number CBs in each CBG of the subset of CBGs being retransmitted.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method of flowchart <NUM> may be performed by a UE (e.g., such as UE <NUM>/<NUM>/<NUM>/<NUM>/<NUM>/<NUM>). At <NUM>, the UE may receive a set of CBGs from a base station. For example, with reference to <FIG>, the UE <NUM> may receive a set of CBGs, e.g., as part of an initial transmission <NUM>, from the base station <NUM>. At <NUM>, the UE may determine that one or more CBGs of the set of CBGs received from the base station failed to be properly decoded at the UE. The determination may be based on, e.g., a failed CRC for the one or more CBGs. For example, referring to <FIG>, the UE <NUM> may fail to decode <NUM> CBGs out of <NUM> CBG transmitted by the base station <NUM>. For example, the UE <NUM> may attempt to decode the received <NUM> CBGs and recover the CRC bits. The UE <NUM> may then run a CRC and determine that CRC failed for <NUM> CBGs. The UE may thus conclude that those <NUM> CBGs have failed decoding. At <NUM>, the UE may send, to the base station, ACK/NACK feedback, indicating the one or more CBGs of the set of CBGs that failed to be properly decoded. In some configurations, the ACK/NACK feedback may be sent by the UE in response to the initial transmission of the set of CBGs received from the base station and upon determining that one or more CBGs of the set of CBGs failed decoding at the UE. As discussed earlier in detail, in some configurations, the ACK/NACK feedback may include a CBG bitmap indicating CBGs (e.g., a subset of the set of CBGs) that failed to be properly decoded. For example, with reference to <FIG> the ACK/NACK feedback <NUM> may convey a CBG bitmap "<NUM>", where a "<NUM>" location in the bitmap may indicate the index of a failed CBG. Decoding failure may be determined from a failed a CRC for the one or more CBGs. In a way, the ACK/NACK feedback from the UE to the base station also serves as a request for retransmission of the one or more CBGs that failed decoding at the UE.

At <NUM>, the UE may receive a retransmission of CBGs in the set of CBGs from the base station, and information indicating the retransmitted CBGs, e.g., indicating the CBGs from the set of CBGs that are retransmitted. If the base station correctly decoded the ACK/NACK feedback from the UE, then the retransmission of CBGs may include the one or more CBGs that failed decoding (that were requested to be retransmitted). For example, referring again to <FIG>, the UE <NUM> may receive a retransmission <NUM> from the base station <NUM> including the <NUM> CBGs and information, e.g., the CBG bitmap "<NUM>", indicating the CBGs that are retransmitted from the base station <NUM>. The CBG mask/bitmap indicating the retransmitted CBGs may be received in a DCI message such as DCI <NUM> of <FIG>. While in some configurations, the information indicating the retransmitted CBGs of the set of CBGs is explicitly indicated in the DCI message as a CBG level bitmap indicates which CBGs of the set of CBGs are being retransmitted, in some other configurations, the information indicating the retransmitted CBGs of the set of CBGs is implicitly indicated in the DCI message within the CRC bits of the DCI message. In such configurations, the UE <NUM> may determine the CBGs in the set of CBGs that are being retransmitted based on the CRC bits. If an error/mistake occurs at the base station in decoding the ACK/NACK feedback from the UE, then the retransmission may not include the same one or more CBGs that failed decoding at the UE and for which retransmission was requested.

In some configurations, the subset of CBGs may be received in a subframe, and the UE may further receive new/additional data (e.g., that is not a retransmission) from the base station in the same subframe as illustrated at <NUM>. For example, in some configurations, in addition to the retransmission of CBGs that may be included in a first TB, the base station <NUM> may also transmit a second TB (or at least a portion of a second TB) of new/additional data in the same subframe/slot that carries the TB of retransmitted CBGs. In some configurations, the first TB may be associated with a first HARQ process and the second TB may be associated with a second HARQ process different than the first HARQ process. In some configurations, the retransmitted CBGs may be received in a first mini-slot corresponding to a first set of symbols in the subframe, and the new data may be received in a second mini-slot corresponding to a second set of symbols in the subframe. In some configurations, in addition to communicating a CBG bitmap, the DCI may further indicate at least one of a slot boundary between a first TB corresponding to the retransmitted CBGs and the second TB corresponding to the new data, or a MCS associated with the new data.

In some configurations, at <NUM> the UE may determine whether the retransmission of CBGs include the one of more CBGs that failed to decode based on the information indicating the retransmitted CBGs of the set of CBGs. For example, with reference to <FIG>, the UE <NUM> may compare the CBG mask/bitmap received in the DCI <NUM> from the base station <NUM> with the CBG bitmap indicated in the ACK/NACK feedback <NUM> to see if there is a match. In some configurations, the operation may proceed based on the determination at <NUM>. In some configurations, upon determining at <NUM> that the retransmitted CBGs as indicated by the DCI do not correspond to the CBGs for which retransmission was requested (e.g., CBG bitmaps do not match), the UE may determine which of the one or more CBGs of the subset still needs to be retransmitted. Assuming that the UE receives a second TB of new data (e.g., as discussed at <NUM>) along with the first TB of retransmitted CBGs, in one configuration at <NUM> the UE may attempt to decode the CBGs corresponding to the new data of the second TB. Since the UE already determined at <NUM> that the retransmission of CBGs does not include all of the one or more CBGs for which retransmission was requested (CBG bitmap comparison failed), at <NUM> the UE may send another ACK/NACK feedback to the base station including a CBG level ACK/NACK (e.g., a CBG bitmap) indicating CBGs that still need to be retransmitted by the base station. For example, the another ACK/NACK feedback may be the ACK/NACK feedback <NUM> discussed supra in connection with <FIG>. In one configuration, depending on whether or not the second TB corresponding to new data is successfully decoded, the another ACK/NACK feedback may further include, e.g., a TB level ACK/NACK indication for the second TB. In addition, the another ACK/NACK feedback <NUM> may further include at least one bit to indicate which TB (e.g., first TB or second TB) is doing CBG level ACK/NACK. The operation may continue in this manner (as indicated by the loop back to <NUM>) until the set of CBGs may be successfully received and decoded or the process may be terminated at some point after certain predetermined number of iterations.

On the other hand, if based on the information indicating the retransmitted CBGs of the set of CBGs (e.g., the DCI) it is determined at <NUM> that the retransmission of CBGs does include the one of more CBGs (e.g., CBG bitmaps match), the operation may proceed to <NUM>. At <NUM> the UE may proceed to decode the received retransmitted CBGs of the first TB and the CBGs corresponding to the new data of the second TB (assuming for discussion purposes that the second TB of new data is received along with the retransmitted CBGs). While the operation may proceed in different ways depending on the result of decoding at <NUM> as may be understood by a person skilled in the art, to facilitate an understanding and simplicity, one specific example is discussed with respect to the operations at <NUM>, <NUM>, and <NUM>.

For discussion purposes, consider that at least some retransmitted CBGs of the first TB received by the UE fail to decode while the CBGs of the second TB corresponding to new data are successfully decoded. At <NUM>, the UE may determine that at least one retransmitted CBG of the first TB failed to decode. For example, with reference to <FIG>, the UE <NUM> may attempt to decode the <NUM> retransmitted CBGs of the first TB received in the retransmission <NUM> and may, for example, fail to decode at least one retransmitted CBG. However, at <NUM> the UE may determine that the CBGs corresponding to the second TB are successfully decoded. Since the second TB successfully decoded, in accordance with one aspect the UE may simply provide a TB level ACK/NACK feedback (e.g., <NUM> bit) to indicate to the decoding status of the second TB to the transmitter (e.g., base station). However, since at least one retransmitted CBG of the first TB failed to decode, if a retransmission of the at least one CBG is desired the UE may need to indicate which at least one retransmitted CBG failed decoding by providing a CBG level ACK/NACK. Thus, in accordance with an aspect, at <NUM> the UE may send a second ACK/NACK feedback including a first CBG level ACK/NACK indicating the at least one retransmitted CBG that failed to be decoded, a TB level ACK indicating that the second TB has been successfully decoded, and an indicator indicating that the CBG level ACK/NACK corresponds to the first TB. For example, with reference to <FIG>, if decoding fails for at least one retransmitted CBG corresponding to the first TB (TB1) received in the retransmission <NUM> while decoding succeeds for the second TB (TB1) received with the retransmitted CBGs, the UE <NUM> may send the ACK/NACK feedback <NUM> including a CBG level ACK/NACK for TB0 to indicate the at least one CBG that failed to decode, a TB level ACK for TB1 to indicate that TB1 successfully decoded, and an indicator (<NUM>-bit) to indicate that the CBG level ACK/NACK (e.g., CBG bitmap) is for CBGs of the first TB (TB0). In another case, all retransmitted CBGs corresponding to the first TB may successfully decode while one or more CBGs of the second TB corresponding to new data may fail decoding. In such as case, the second ACK/NACK feedback may include a TB level ACK (<NUM>-bit) for the first TB, a CBG level ACK/NACK for the second TB (multibit), and an indicator (<NUM>-bit) to indicate that the CBG level ACK/NACK corresponds to the second TB (TB1). The operation may continue in this manner (as indicated by the loop back to <NUM>) until the set of CBGs may be successfully received and decoded or the process may be terminated at some point after certain predetermined number of iterations. For example, in response to the second ACK/NACK, the UE may receive another transmission that may include the at least one retransmitted CBG (and optionally another TB of new data). The UE may also receive DCI indicating the CBGs being retransmitted. The UE may subsequently perform similar processing as discussed with respect to <NUM> through <NUM> and based on a result of decoding send an ACK/NACK. For example, assuming successful decoding, the UE may send an ACK and no further retransmission may be needed.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM>. The apparatus <NUM> may be a base station (e.g., such as base station <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). The apparatus <NUM> may include a reception component <NUM>, a determination component <NUM>, a DCI generation component <NUM>, a control component <NUM>, and a transmission component <NUM>.

The reception component <NUM> may be configured to receive messages and/or other information from other devices including, e.g., UE <NUM>. The signals/information received by the reception component <NUM> may be provided to one or more components of the apparatus <NUM> for further processing and use in performing various operations in accordance with the methods discussed supra including the method of flowchart <NUM>. In some configurations, the reception component <NUM> may receive, from a UE (e.g., UE <NUM>), ACK/NACK feedback indicating that a subset of CBGs of a set of transmitted CBGs failed to be decoded at the UE. In some configurations, the ACK/NACK feedback is in response to an initial transmission of the set of CBGs from the apparatus <NUM> to the UE <NUM>. For example, referring to <FIG>, the received ACK NACK feedback may be the ACK/NACK feedback <NUM> including the CBG bitmap received by the base station <NUM> from the UE <NUM>.

In some configurations, reception component <NUM> may process the received ACK/NACK feedback and provide the feedback information to the determination component <NUM>. The determination component <NUM> may be configured to determine, based on the information (e.g., CBG mask/bitmap in the received feedback) the subset of the CBGs that need to be retransmitted to the UE <NUM>. The determination component <NUM> may be further configured to provide the information regarding the subset of CBGs to be retransmitted to the DCI generation component <NUM> and/or the transmission component <NUM>.

The DCI generation component <NUM> may be configured to generate downlink control information including information indicating the subset of CBGs being retransmitted by the apparatus <NUM> in response to the received ACK/NACK feedback. In some configurations, based on the input from the determination component <NUM>, the DCI generation component <NUM> may determine which CBGs are being retransmitted and include the information indicating the subset of CBGs being retransmitted in a DCI message generated by the DCI generation component <NUM>. In some configurations, the information indicating the subset of CBGs being retransmitted may be a CBG bitmap generated by the DCI generation component <NUM>. For example, with reference to <FIG>, the information indicating the subset of CBGs being retransmitted may be the CBG bitmap included in the DCI <NUM>. In some other configurations, rather than an explicit indication of the CBGs being retransmitted, the CBG bitmap indicating the subset of CBGs being retransmitted may be conveyed via implicit signaling, e.g., in the CRC bits. For example, in some configurations, the CBG bitmap may be implicitly indicated in the CRC bits of the DCI payload as discussed in more detail with respect to <FIG>.

The transmission component <NUM> may be configured to transmit data and/or other control information to one or more external devices, e.g., including UE <NUM>. In some configurations, the transmission component <NUM> alone, in combination with and/or under the control of the controller/control component <NUM>, may be configured to transmit, e.g., a set of CBGs associated with a TB to the UE <NUM>, e.g., in a first/initial transmission. For example, with reference to <FIG>, the initial transmission <NUM> may include a TB including <NUM> CBGs to the UE. The transmission component <NUM> alone, in combination with and/or under the control of a controller/control component <NUM>, may be further configured to retransmit the subset of CBGs based on the received ACK/NACK feedback. The transmission component <NUM> may be further configured to transmit the information indicating the subset of CBGs being retransmitted, e.g., as part of the DCI. In some configurations, the subset of CBGs is retransmitted in a subframe and corresponds to a first TB. In some such configurations, the transmission component <NUM> may be further configured to transmit at least a portion of a second TB corresponding to new data to the UE in the subframe. In some such configurations, the generated DCI (from DCI generation component <NUM>) may further indicate at least one of a slot boundary between a first transport block corresponding to the subset of CBGs and a second transport block corresponding to new data, or a MCS associated with the new data.

In one MIMO configuration, the initially transmitted set of CBGs may correspond to a first TB and a second TB that may be transmitted by the transmission component <NUM> via a first MIMO transmission. In such a MIMO configuration the first TB and the second TB may be associated with a first HARQ process. The subset of CBGs being retransmitted is also associated with the first HARQ process and the transmission component <NUM> may be configured to retransmit the subset of CBGs via a second MIMO transmission in a subframe along with one or more TBs corresponding to new data associated with a second HARQ process.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium/memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium/memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer-readable medium/memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the base station <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication includes means for receiving, from a UE, ACK/NACK feedback indicating that a subset of CBGs of a set of transmitted CBGs failed to be decoded. In some configurations, the apparatus <NUM>/<NUM>' further comprises means for retransmitting, based on the ACK/NACK feedback, the subset of CBGs. In some configurations, the apparatus <NUM>/<NUM>' may further include means for transmitting information indicating the subset of CBGs that is being retransmitted.

In some configurations, the subset of CBGs is retransmitted in a subframe and corresponds to a first TB. In one such configuration, the means for transmitting may be further configured to transmit at least a portion of a second TB corresponding to new data to the UE in the subframe. In some configurations, the subset of CBGs is retransmitted in a first mini-slot corresponding to a first set of symbols in the subframe, and the portion of the second TB is transmitted in a second mini-slot corresponding to a second set of symbols in the subframe. The first set of symbols and the second set of symbols may be different. In some configurations, the first set of symbols may be earlier in time than the second set of symbols. The first set of symbols and the second set of symbols may be the same. In one configuration, the subset of CBGs is retransmitted in a first set of resource blocks of the subframe, and the new data is transmitted in a second set of resource blocks of the subframe, where the first set of resource blocks may be different than the second set of resource blocks. In some configurations, the first TB may be associated with a first HARQ process and the second TB may be associated with a second HARQ process different than the first HARQ process.

In one configuration, the set of CBGs corresponds to a first TB and a second TB transmitted via a first MIMO transmission, where the first TB and the second TB may be associated with a first HARQ process, and the ACK/NACK feedback may be received in response to the first MIMO transmission. The subset of CBGs may be associated with the first HARQ process and may be retransmitted via a second MIMO transmission in a subframe along with one or more TBs corresponding to new data associated with a second HARQ process.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an example apparatus <NUM>. The apparatus <NUM> may be a UE (e.g., such as UE <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). The apparatus <NUM> may include a reception component <NUM>, a decoder/decoding component <NUM>, a decoding result determination component <NUM>, an ACK/NACK feedback generation component <NUM>, a determination component <NUM>, a control component <NUM>, and a transmission component <NUM>.

The reception component <NUM> may be configured to receive messages and/or other information from other devices including, e.g., base station <NUM>. The signals/information received by the reception component <NUM> may be provided to one or more components of the apparatus <NUM> for further processing and use in performing various operations in accordance with the methods discussed supra including the method of flowchart <NUM>. In some configurations, the reception component <NUM> may receive, from a base station (e.g., base station <NUM>), a set of CBGs associated with a TB, e.g., in a first/initial transmission. For example, with reference to <FIG>, the UE <NUM> may receive the initial transmission <NUM> that may include a TB including <NUM> CBGs from the base station <NUM>. In some configurations, the reception component <NUM> may be further configured to receive a retransmission of CBGs (e.g., a subset of CBGs from the set of initially transmitted CBGs), and information (e.g., included in DCI) indicating the retransmitted CBGs of the set of CBGs. In some configurations, the retransmitted CBGs may correspond to a first TB received in a subframe. In some such configurations, the reception component <NUM> may be further configured to receive at least a portion of a second TB corresponding to new data in the subframe.

The decoder/decoding component <NUM> may be configured to decode the received information, e.g., the set of CBGs received in the initial transmission, retransmitted subset of CBGs, and/or other received coded information. In some configurations, the decoding component may be implemented as part of the reception component <NUM>. The decoding result determination component <NUM> may be configured to determine (e.g., based on decoding output received from the decoding component <NUM>) whether the received set of CBGs is successfully decoded or failed decoding. In some configurations, the decoding result determination component <NUM> may include a CRC component to perform a CRC in order determine whether or not a CBG has been successfully decoded. In some configurations, the decoding result determination component <NUM> may be implemented as part of the decoding component <NUM>. In some configurations, the decoding result determination component <NUM> may be configured to determine that one or more CBGs of a set of CBGs received from a base station failed to be properly decoded. In some configurations, the decoding result determination component <NUM> may be further configured to determine that at least one retransmitted CBG of the first TB associated with retransmitted CBGs failed to be properly decoded and that the CBGs of the second TB (corresponding to new data) has been successfully decoded. The determined decoding result information, e.g., regarding the CBGs that failed decoding may be provided to one or more other components (e.g., such as the ACK/NACK feedback generation component <NUM>) of the apparatus <NUM>.

The ACK/NACK feedback generation component <NUM> may be configured to generate an ACK/NACK feedback based on information received from the decoding result determination component <NUM>. For example, the ACK/NACK feedback generation component <NUM> may be configured to generate an ACK/NACK feedback indicating the one or more CBGs of the received set of CBGs that failed to be properly decoded. For example, the various ACK/NACK feedbacks sent from a UE to a base station discussed in connection with <FIG> may be generated by the ACK/NACK feedback generation component <NUM>. For example, in one configuration the ACK/NACK feedback generation component <NUM> may be configured to generate a second ACK/NACK feedback including a first CBG level ACK/NACK indicating the at least one retransmitted CBG that failed to be properly decoded, a TB level ACK indicating that the second TB has been successfully decoded, and an indicator indicating that the CBG level ACK/NACK corresponds to the first TB.

The determination component <NUM> may be configured to process the received DCI to determine various information and/or parameters in accordance with the features of the disclosure. In some configurations, the determination component <NUM> may be configured to determine whether a received retransmission of CBGs include the one of more CBGs that failed to be properly decoded based on the information indicating the retransmitted CBGs of the set of CBGs, where the information indicating the retransmitted CBGs may be received as part of the DCI. In some configurations, the information indicating the retransmitted CBGs of the set of CBGs is explicitly indicated in the DCI as a CBG level bitmap that indicates which CBGs of the set of CBGs are being retransmitted. In some such configurations, the determination component <NUM> may be configured to compare the CBG level bitmap from the DCI with a CBG mask/bitmap from an ACK/NACK feedback sent in response to determining a failure to decode the one or more CBGs of the initially received set of CBGs. As discussed in detail earlier with respect to <FIG>, the CBG bitmap comparison may be performed to check if the retransmitted CBGs include the one or more CBGs that failed decoding and that were requested to be retransmitted.

In some configurations, an ACK/NACK feedback may be generated further based on information received from the determination component <NUM> indicating whether the retransmitted CBGs are the same as and/or include the CBGs for which retransmission was requested. For example, in one configuration the determination component <NUM> may determine based on the DCI that the retransmitted CBGs do not include all the CBGs that failed decoding and for which retransmission was requested (e.g., CBG bitmap comparison by the determination component may have failed). In such a case, based on an input from the determination component <NUM>, the ACK/NACK feedback generation component <NUM> may generate another ACK/NACK feedback (for sending to the base station <NUM>) indicating the CBGs that still need to be retransmitted.

In some configurations, the determination component <NUM> may be further configured to determine, based on the information in the received DCI, at least one of a slot boundary between a first TB corresponding to the retransmitted CBGs of the set of CBGs and a second TB corresponding to new data, or a MCS associated with the new data. In some configurations, the determination component <NUM> may be further configured to determine MCS associated with the retransmitted CBGs of the set of CBGs based on a number of resources allocated for CBG retransmission and the information (e.g., in DCI) indicating the retransmitted CBGs of the set of CBGs. In some configurations, the information indicating the retransmitted CBGs of the set of CBGs is implicitly indicated in the DCI within CRC bits and the determination component <NUM> may be further configured to determine the retransmitted CBGs of the set of CBGs that are included in the retransmission based on the CRC bits.

The transmission component <NUM> may be configured to transmit the ACK/NACK feedback(s), user data and/or other information to one or more external devices, e.g., including base station <NUM>. In some configurations, the transmission component <NUM> alone, in combination with and/or under the control of the controller/control component <NUM>, may be configured to send ACK/NACK feedback(s) generated by the ACK/NACK generation component in accordance with the methods disclosed supra. In one configuration, the transmission component <NUM> alone, in combination with and/or under the control of the controller/control component <NUM>, may be configured to send the ACK/NACK feedback indicating the one or more CBGs that failed to be properly decoded to the base station <NUM>. In one configuration, the transmission component <NUM> alone, in combination with and/or under the control of the controller/control component <NUM>, may be configured to send, to the base station <NUM>, the second ACK/NACK feedback including a first CBG level ACK/NACK indicating the at least one retransmitted CBG that failed to be properly decoded, a TB level ACK indicating that the second TB has been successfully decoded, and an indicator indicating that the CBG level ACK/NACK corresponds to the first TB.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium/memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium/memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer-readable medium/memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>.

In one configuration, the apparatus <NUM>/<NUM>' for wireless communication may include means for determining that one or more CBGs of a set of CBGs received from a base station failed to be properly decoded at the UE. The apparatus <NUM>/<NUM>' may further include means for sending, to the base station, ACK/NACK feedback indicating the one or more CBGs that failed to be properly decoded. The apparatus <NUM>/<NUM>' may further include means for receiving, from the base station, a retransmission of CBGs of the set of CBGs in response to the ACK/NACK feedback, and information indicating retransmitted CBGs of the set of CBGs.

In some configurations, the retransmitted CBGs correspond to a first TB, and the retransmission of CBGs is received in a subframe. In some such configurations, the apparatus <NUM>/<NUM>' may further include means for receiving new data corresponding to a second TB from the base station in the subframe. In some configurations, the first TB is associated with a first HARQ process and the second TB is associated with a second HARQ process different than the first HARQ process.

In some configurations, the apparatus <NUM>/<NUM>' may further include means for determining whether the retransmission of CBGs include the one of more CBGs that failed to be properly decoded based on the information indicating the retransmitted CBGs of the set of CBGs. In some configurations, the means for sending ACK/NACK feedback may be configured to send another (e.g., a second) ACK/NACK feedback based on determining whether the retransmission of CBGs include the one of more CBGs that failed to be properly decoded.

In some configurations, the apparatus <NUM>/<NUM>' may include means for determining that at least one retransmitted CBG of the first TB failed to be properly decoded, and for determining that the second TB has been successfully decoded. In some such configurations, the means for sending ACK/NACK feedback may be configured to send to the base station, a second ACK/NACK feedback, the second ACK/NACK feedback including a first CBG level ACK/NACK indicating the at least one retransmitted CBG that failed to be properly decoded, a TB level ACK indicating that the second TB has been successfully decoded, and an indicator indicating that the CBG level ACK/NACK corresponds to the first TB.

It is understood that the specific order or hierarchy of blocks in the processes/flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes/flowcharts may be rearranged.

Claim 1:
A method of wireless communication of a base station, comprising:
receiving (<NUM>), from a user equipment, UE, an acknowledgement/negative acknowledgement, ACK/NACK, feedback indicating that a subset of codeblock groups, CBGs, of a set of transmitted CBGs failed to be properly decoded;
retransmitting (<NUM>), based on the ACK/NACK feedback, the subset of CBGs; and
transmitting (<NUM>) a downlink control information, DCI, message indicating the subset of CBGs that is being retransmitted, wherein the DCI message includes a CBG bitmap indicating which CBGs are retransmitted.