Patent ID: 7391817

Claim:
A method for determining antenna weights for M transmission antennas in a closed-loop transmit diversity system, comprising the steps of: estimating channel gains from the M transmission antennas to a receiver; and determining antenna weights for the M transmission antennas based on the estimated channel gains, wherein the antenna weights are determined to minimize a signal error in accordance with a fixed average transmission power per transmission symbol from the M transmission antennas; wherein the antenna weights are determined by w m = h m * ⁢ N o 2 ⁢ E s ⁢ W ⁡ ( ( E s 2 ⁢ π ⁢ λ ⁢ ⁢ N o ⁢ ∑ i = 1 M ⁢ ⁢  h i  2 ) 2 ) ∑ i = 1 M ⁢ ⁢  h i  2 where w wm is an antenna weight for an m th transmission antenna, m is an integer between 1 and M, h m is a channel gain from an m th transmission antenna to a receiver, W is a Lambert W function, E s is symbol energy, λ is a constant determined so as to fix average transmission power per transmission symbol, and N 0 is a variance of additive white Gaussian noise (AWGN).