Demodulation reference signal resource allocation
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, to a network entity, demodulation reference signal (DMRS) capability information that indicates a number of orthogonal DMRS ports for DMRS communications. The UE may receive, from the network entity, information that is associated with a DMRS port mapping for the number of orthogonal DMRS ports and that indicates to restrict a resource allocation for a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) to an integer that is a multiple of two for each contiguous physical resource block, to restrict a virtual resource block to physical resource block (VRB-to-PRB) mapping, or to restrict the number of orthogonal DMRS ports such that a legacy number of DMRS ports and an extended number of DMRS ports are not multiplexed in a same code division multiplexing (CDM) group. Numerous other aspects are described.
1 . An apparatus for wireless communication at a user equipment (UE), comprising:
one or more memories; and
one or more processors, coupled to the one or more memories, configured to:
transmit, to a network entity, demodulation reference signal (DMRS) capability information that indicates a number of orthogonal DMRS ports for DMRS communications; and
receive, from the network entity, information that is associated with a DMRS port mapping for the number of orthogonal DMRS ports and that indicates to:
restrict a resource allocation for a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) associated with the number of orthogonal DMRS ports to an integer that is a multiple of two for each contiguous physical resource block;
restrict a virtual resource block to physical resource block (VRB-to-PRB) mapping for the number of orthogonal DMRS ports; or
restrict the number of orthogonal DMRS ports, wherein a first number of DMRS ports and a second number of DMRS ports are not multiplexed in a same code division multiplexing (CDM) group, the first number of DMRS ports being based at least in part on a length two frequency domain orthogonal cover code (FD-OCC) and the second number of DMRS ports being based at least in part on a length four FD-OCC.
2 . The apparatus of claim 1 , wherein the first number of DMRS ports is a legacy number of DMRS ports, the second number of DMRS ports is an extended number of DMRS ports, and the UE is a multi-user UE.
3 . The apparatus of claim 1 , wherein the DMRS capability information is associated with a DMRS configuration type that uses every other resource element within one or more symbols allocated to the DMRS.
4 . The apparatus of claim 3 , wherein the number of orthogonal DMRS ports is eight ports for a single symbol DMRS for the DMRS configuration type or sixteen ports for a two symbol DMRS for the DMRS configuration type.
5 . The apparatus of claim 1 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports is included in a VRB-to-PRB mapping bitfield of downlink control information (DCI).
6 . The apparatus of claim 5 , wherein a value of the VRB-to-PRB mapping bitfield is zero or is not included in the DCI.
7 . The apparatus of claim 5 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports indicates that a plurality of PRBs associated with the number of orthogonal DMRS ports are non-interleaved or that the plurality of PRBs associated with the number of orthogonal DMRS ports are contiguous in a physical domain.
8 . The apparatus of claim 1 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports indicates that a number of VRB allocations is double a resource block bundle size.
9 . The apparatus of claim 8 , wherein the resource block bundle size is two resource blocks or four resource blocks.
10 . The apparatus of claim 1 , wherein the one or more processors, to receive the information that is associated with the DMRS port mapping, are configured to receive a PDSCH resource allocation that includes the information or a PUSCH resource allocation that includes the information.
11 . The apparatus of claim 1 , wherein the one or more processors are further configured to restrict resource allocation by scheduling PRBs for a PDSCH or PUSCH as contiguous PRBs in the frequency domain.
12 . The apparatus of claim 1 , wherein the one or more processors are further configured to determine the number of DMRS ports based on DMRS capability information transmitted by the UE.
13 . The apparatus of claim 1 , wherein the one or more processors are further configured to restrict allocation by performing a mapping between VRBs and PRBs according to an indication received from the network entity.
14 . The apparatus of claim 1 , wherein the one or more processors are further configured to, in response to receiving the information associated with the DMRS port mapping, apply a scheduling restriction that prevents assignment of DMRS ports based at least in part on a length two FD-OCC and DMRS ports based at least in part on a length four FD-OCC to the same CDM group.
15 . A method of wireless communication performed by a user equipment (UE), comprising:
transmitting, to a network entity, demodulation reference signal (DMRS) capability information that indicates a number of orthogonal DMRS ports for DMRS communications; and
receiving, from the network entity, information that is associated with a DMRS port mapping for the number of orthogonal DMRS ports and that indicates to:
restrict a resource allocation for a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) associated with the number of orthogonal DMRS ports to an integer that is a multiple of two for each contiguous physical resource block;
restrict a virtual resource block to physical resource block (VRB-to-PRB) mapping for the number of orthogonal DMRS ports; or
restrict the number of orthogonal DMRS ports, wherein a first number of DMRS ports and a second number of DMRS ports are not multiplexed in a same code division multiplexing (CDM) group, the first number of DMRS ports being based at least in part on a length two frequency domain orthogonal cover code (FD-OCC) and the second number of DMRS ports being based at least in part on a length four FD-OCC.
16 . The method of claim 15 , wherein the first number of DMRS ports is a legacy number of DMRS ports, the second number of DMRS ports is an extended number of DMRS ports, and the UE is a multi-user UE.
17 . The method of claim 15 , wherein the DMRS capability information is associated with a DMRS configuration type that uses every other resource element within one or more symbols allocated to the DMRS.
18 . The method of claim 15 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports is included in a VRB-to-PRB mapping bitfield of downlink control information (DCI).
19 . The method of claim 18 , wherein a value of the VRB-to-PRB mapping bitfield is zero or is not included in the DCI.
20 . The method of claim 18 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports indicates that a plurality of PRBs associated with the number of orthogonal DMRS ports are non-interleaved or that the plurality of PRBs associated with the number of orthogonal DMRS ports are contiguous in a physical domain.
21 . The method of claim 15 , wherein the information that indicates to restrict the VRB-to-PRB mapping for the number of orthogonal DMRS ports indicates that a number of VRB allocations is double a resource block bundle size.
22 . The method of claim 15 , further comprising: receiving, from the network entity, an indication that the resource allocation for DMRS ports is to be an integer multiple of two resource blocks.
23 . The method of claim 15 , further comprising: transmitting, to the network entity, DMRS capability information indicating a number of orthogonal DMRS ports supported by the UE.
24 . The method of claim 15 , further comprising:
applying a scheduling restriction to prevent DMRS ports associated with legacy DMRS configurations from being scheduled with DMRS ports associated with enhanced DMRS configurations in a same CDM group.
25 . The method of claim 15 , further comprising receiving, from the network entity, an indication to apply the FD-OCC to the DMRS for every three resource elements of the DMRS or every six resource elements of the DMRS.
26 . The method of claim 15 , further comprising restricting a scheduling of the number of orthogonal DMRS ports for multi-user MIMO by assigning different UEs to distinct CDM groups.
27 . A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising:
one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to:
transmit, to a network entity, demodulation reference signal (DMRS) capability information that indicates a number of orthogonal DMRS ports for DMRS communications; and
receive, from the network entity, information that is associated with a DMRS port mapping for the number of orthogonal DMRS ports and that indicates to:
restrict a resource allocation for a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) associated with the number of orthogonal DMRS ports to an integer that is a multiple of two for each contiguous physical resource block;
restrict a virtual resource block to physical resource block (VRB-to-PRB) mapping for the number of orthogonal DMRS ports; or
restrict the number of orthogonal DMRS ports, wherein a first number of DMRS ports and a second number of DMRS ports are not multiplexed in a same code division multiplexing (CDM) group, the first number of DMRS ports being based at least in part on a length two frequency domain orthogonal cover code (FD-OCC) and the second number of DMRS ports being based at least in part on a length four FD-OCC.
28 . The non-transitory computer-readable medium of claim 27 , wherein the instructions further cause the UE to restrict resource allocation to cause scheduled PRBs for a PDSCH or PUSCH to be contiguous in the frequency domain.
29 . The non-transitory computer-readable medium of claim 27 , wherein the instructions further cause the UE to determine the number of DMRS ports based on DMRS capability information transmitted by the user equipment.
30 . An apparatus for wireless communication, comprising:
means for transmitting demodulation reference signal (DMRS) capability information that indicates a number of orthogonal DMRS ports for DMRS communications; and
means for receiving information that is associated with a DMRS port mapping for the number of orthogonal DMRS ports and that indicates to:
restrict a resource allocation for a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) associated with the number of orthogonal DMRS ports to an integer that is a multiple of two for each contiguous physical resource block;
restrict a virtual resource block to physical resource block (VRB-to-PRB) mapping for the number of orthogonal DMRS ports; or
restrict the number of orthogonal DMRS ports, wherein a first number of DMRS ports and a second number of DMRS ports are not multiplexed in a same code division multiplexing (CDM) group, the first number of DMRS ports being based at least in part on a length two frequency domain orthogonal cover code (FD-OCC) and the second number of DMRS ports being based at least in part on a length four FD-OCC.