Adds opt-in MU-MIMO downlink co-scheduling to the production
proportional-fair scheduler (pf_dl). When OAI_MU_MIMO=1 is set in
the gNB process env, after the leader UE is allocated we look ahead
in the PF-sorted candidate list for an orthogonal-PMI partner. If
found and the partner can secure its own CCE+PUCCH, both UEs share
the same RB allocation with distinct DMRS CDM groups (port 1000 vs
port 1001) and are forced to the same MCS/TBS.
Orthogonality test (4-port Type I rank-1 codebook, N1=2, N2=1):
same x1 (same beam), x2 differing by 2 (co-phasing pairs {0,2} or
{1,3}). Both UEs must report rank-1.
Default OFF — set OAI_MU_MIMO=1 to enable. Builds on the upstream
FAPI/PHY MU-MIMO plumbing (commits 3707d52c95, 498d241d75,
9952996c5d) which carries antenna-port and DMRS-CDM metadata down
to the PHY transmit path.
maki
766d0a4bd3