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=w^HH^HHw (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 = w^H(H₁^HH₁+ H₂^HH₂+)w (2)

where H_i 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 = w^H((H₁^HH₁)+ (1-)(H₂^HH₂+))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