A.2 Computation of feedback information for closed loop mode 1 transmit diversity
25.2143GPPPhysical layer procedures (FDD)Release 17TS
In non-soft handover case, the computation of feedback information can be accomplished by e.g. solving for weight vector, w, that maximises.
P=wHHHHw (1)
where
H=h1 h2 and w = [ w1, w2 ]T
and where the column vectors h1 and h2 represent the estimated channel impulse responses for the transmission antennas 1 and 2, of length equal to the length of the channel impulse response. The elements of w correspond to the adjustments computed by the UE.
During soft handover, the antenna weight vector, w can be, for example, determined so as to maximise the criteria function:
P = wH(H1HH1+ H2HH2+)w (2)
where Hi is an estimated channel impulse response for BS#i. In regular SHO, the set of BS#i corresponds to the active set.
If HS-PDSCH is present, the UE may emphasize the HS-PDSCH serving cell. In this case the antenna weight vector, w can be, for example, determined so as to maximise the criteria function:
P = wH((H1HH1)+ (1-)(H2HH2+))w
where BS#1 is the HS-PDSCH serving cell and coefficient is less than or equal to 1. For example = 0.7 enhances HS-DSCH performance while ensuring that there is only a small degradation on the DPCH.
Annex B (Informative):
Power control