Enhanced beam-based codebook subset restriction signaling

A method of enabling codebook subset restriction performed by a network node, the method comprising:

• generating codebook subset restriction (CBSR) signaling, the CBSR signaling including a bitmap comprising a plurality of bits, wherein:
• precoders in a first group of codebooks are constructed using a vector from a first set of vectors;
• precoders in a second group of codebooks are constructed using a vector from a second set of vectors;
• vectors from the first set of vectors have an associated index l1, m;
• vectors from the second set of vectors have an associated index l2, m;
• the vectors from the second set of vectors are different from the vectors from the first set of vectors;
• a bit of the plurality of bits mapped to an l1, m index indicates whether a vector with index l1, m from the first set of vectors is restricted;
• bits of the plurality of bits mapped to l1, m indices, with l1 within a window [2l2−Δ1, 2l2+Δ2], indicate whether a vector with index l2, m from the second set of vectors is restricted;
• and
• the CBSR signaling is configured to cause a user equipment (UE) to restrict precoders selectable from the codebooks based on the restricted vectors;
• and
• transmitting the CBSR signaling to the UE.

A user equipment (UE) for performing codebook subset restriction, the UE comprising:

• processing circuitry and a memory, wherein the memory contains instructions that, when executed by the processing circuitry, cause the UE to:
• receive, from a network node, codebook subset restriction (CBSR) signaling, the CBSR signaling including a bitmap comprising a plurality of bits, wherein:
• precoders in a first group of codebooks are constructed using a vector from a first set of vectors;
• precoders in a second group of codebooks are constructed using a vector from a second set of vectors;
• vectors from the first set of vectors have an associated index l1, m;
• vectors from the second set of vectors have an associated index l2;
• the vectors from the second set of vectors are different from the vectors from the first set of vectors;
• a bit of the plurality of bits mapped to an l1, m index indicates whether a vector with index l1, m from the first set of vectors is restricted;
• and
• bits of the plurality of bits mapped to l1, m indices, with l1 within a window [2l2−Δ1, 2l2+Δ2], indicate whether a vector with index l2, m from the second set of vectors is restricted;
• and
• restrict precoders selectable from the codebooks based on the restricted vectors.

A network node for enabling codebook subset restriction, the network node comprising:

• processing circuitry and a memory, the memory containing instructions that, when executed by the processing circuitry, cause the network node to:
• generate codebook subset restriction (CBSR) signaling, the CBSR signaling including a bitmap comprising a plurality of bits, wherein:
• precoders in a first group of codebooks are constructed using a vector from a first set of vectors;
• precoders in a second group of codebooks are constructed using a vector from a second set of vectors;
• vectors from the first set of vectors have an associated index l1, m;
• vectors from the second set of vectors have an associated index l2, m;
• the vectors from the second set of vectors are different from the vectors from the first set of vectors;
• a bit of the plurality of bits mapped to an l1, m index indicates whether a vector with index l1, m from the first set of vectors is restricted;
• bits of the plurality of bits mapped to l1, m indices, with l1 within a window [2l2−Δ1, 2l2+Δ2], indicate whether a vector with index l2, m from the second set of vectors is restricted;
• and
• the CBSR signaling is configured to cause a user equipment (UE) to restrict precoders selectable from the codebooks based on the restricted vectors;
• and
• transmit the CBSR signaling to the UE.