Transport block size and soft buffer management for shared channel transmissions
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may communicate a shared channel transmission (e.g., a physical uplink shared channel (PUSCH) or a physical downlink shared channel (PDSCH)) that exceeds a maximum transport block (TB) size (TBS) for the UE. A shared channel transmission may be scheduled across slot boundaries. For example, a start and length indicator value may schedule a shared channel transmission across slots. A UE may have a maximum TBS the UE is able to manage, for example, based on hybrid automatic repeat request (HARQ) buffer sizes. When the TBS indicated by the scheduling information for a shared channel transmission is greater than the maximum TBS for a UE, the shared channel transmission may be split into multiple small TBs, each having a TBS that satisfies the maximum TBS. Code block segmentation and cyclic redundancy check attachment may be per small TB.
1 . A method for wireless communications at a user equipment (UE), comprising:
receiving control signaling that schedules a set of resources for a shared channel transmission, wherein the set of resources indicates that a first transport block size for the shared channel transmission exceeds a maximum transport block size; and
communicating the shared channel transmission via the set of resources, wherein the shared channel transmission comprises a plurality of transport blocks associated with respective code blocks and respective cyclic redundancy check bits, and wherein a second transport block size for each of the plurality of transport blocks is based at least in part on the maximum transport block size.
2 . The method of claim 1 , further comprising:
communicating an indication of the maximum transport block size, wherein communication of the shared channel transmission is based at least in part on communication of the indication of the maximum transport block size.
3 . A user equipment (UE), comprising:
one or more memories storing processor-executable code; and
one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the UE to:
receive control signaling that schedules a set of resources for a shared channel transmission, wherein the set of resources indicates that a first transport block size for the shared channel transmission exceeds a maximum transport block size; and
communicate the shared channel transmission via the set of resources, wherein the shared channel transmission comprises a plurality of transport blocks associated with respective code blocks and respective cyclic redundancy check bits, and wherein a second transport block size for each of the plurality of transport blocks is based at least in part on the maximum transport block size.
4 . The UE of claim 3 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
communicate an indication of the maximum transport block size, wherein communication of the shared channel transmission is based at least in part on communication of the indication of the maximum transport block size.
5 . The UE of claim 3 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
receive, via the control signaling, an indication of a set of hybrid automatic repeat request identifiers associated with a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks.
6 . The UE of claim 3 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
receive, via the control signaling, an indication of a first hybrid automatic repeat request identifier associated with a first transport block group of a set of transport block groups, wherein each transport block group of the set of transport block groups includes one or more of the plurality of transport blocks, and wherein respective hybrid automatic repeat request identifiers for a remainder of the set of transport block groups are based at least in part on the first hybrid automatic repeat request identifier.
7 . The UE of claim 3 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
receive, via the control signaling, an indication of a hybrid automatic repeat request identifier associated with the shared channel transmission and a quantity of acknowledgment bit fields associated with the hybrid automatic repeat request identifier that correspond to a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks.
8 . The UE of claim 3 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
receive, via the control signaling, an indication of a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks;
transmit a negative acknowledgment for a transport block group of the set of transport block groups; and
update a set of pages of a soft buffer of the UE based at least in part on transmission of the negative acknowledgment, wherein each page of the set of pages corresponds to a respective transport block of the transport block group, and wherein a page size for the soft buffer is based at least in part on the maximum transport block size.
9 . The UE of claim 8 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
purging, based at least in part on transmission of the negative acknowledgment, a second set of pages from the soft buffer of the UE, wherein a first quantity of pages of the set of pages is equal to a second quantity of pages of the second set of pages.
10 . The UE of claim 9 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
transmit, with the negative acknowledgment, an indication of a first hybrid automatic repeat request identifier associated with the transport block group, wherein the second set of pages are associated with a second hybrid automatic repeat request identifier.
11 . The UE of claim 3 , wherein the second transport block size is based at least in part on the first transport block size divided by the maximum transport block size.
12 . A network entity, comprising:
one or more memories storing processor-executable code; and
one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the network entity to:
output control signaling that schedules a set of resources for a shared channel transmission, wherein the set of resources indicates that a first transport block size for the shared channel transmission exceeds a maximum transport block size; and
communicate the shared channel transmission via the set of resources, wherein the shared channel transmission comprises a plurality of transport blocks associated with respective code blocks and respective cyclic redundancy check bits, and wherein a second transport block size for each of the plurality of transport blocks is based at least in part on the maximum transport block size.
13 . The network entity of claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
communicate an indication of the maximum transport block size, wherein communication of the shared channel transmission is based at least in part on communication of the indication of the maximum transport block size.
14 . The network entity of claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
output, via the control signaling, an indication of a set of hybrid automatic repeat request identifiers associated with a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks.
15 . The network entity of claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
output, via the control signaling, an indication of a first hybrid automatic repeat request identifier associated with a first transport block group of a set of transport block groups, wherein each transport block group of the set of transport block groups includes one or more of the plurality of transport blocks, and wherein respective hybrid automatic repeat request identifiers for a remainder of the set of transport block groups are based at least in part on the first hybrid automatic repeat request identifier.
16 . The network entity of claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
output, via the control signaling, an indication of a hybrid automatic repeat request identifier associated with the shared channel transmission and a quantity of acknowledgment bit fields associated with the hybrid automatic repeat request identifier that correspond to a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks.
17 . The network entity of claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
output, via the control signaling, an indication of a set of transport block groups associated with the shared channel transmission, wherein each of the set of transport block groups includes one or more of the plurality of transport blocks;
obtain, from a user equipment (UE), a negative acknowledgment for a transport block group of the set of transport block groups; and
determine a set of pages of a soft buffer of the UE that are updated based at least in part on the negative acknowledgment, wherein each page of the set of pages corresponds to a respective transport block of the transport block group, and wherein a page size for the soft buffer is based at least in part on the maximum transport block size.
18 . The network entity of claim 17 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
determine, based at least in part on the negative acknowledgment, a second set of pages from that are purged from the soft buffer of the UE, wherein a first quantity of pages of the set of pages is equal to a second quantity of pages of the second set of pages.
19 . The network entity of claim 18 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the network entity to:
obtain, with the negative acknowledgment, an indication of a first hybrid automatic repeat request identifier associated with the transport block group, wherein the second set of pages are associated with a second hybrid automatic repeat request identifier.
20 . The network entity of claim 12 , wherein the second transport block size is based at least in part on the first transport block size divided by the maximum transport block size.