A method of transmitting a signal from a transmitter to a receiver over a communication channel, the transmitter having a first and a second antenna transmitting respective first and second components of the signal, the method comprising the steps of: perturbing in the transmitter a transmit diversity parameter from its nominal value at a perturbation rate by modulating the transmit diversity parameter with respect to the nominal value in a first direction for at least said first component; receiving from the receiver feedback signals (FB i) according to a communication protocol, the feedback signals including feedback information relating to the perturbed signals as received at said receiver; and based at least on said feedback information, adjusting at the transmitter the nominal value of the transmit diversity parameter by preserving the nominal value or by increasing or decreasing the nominal value by a step size (Δφ) determined by a fractional scaling function ( f) of weighted values (s) of the feedback signals wherein: said scaling function ( f) is given by: f s = { b a s, − a ≤ s ≤ a b, s > a − b, s < − a wherein a and b are parameters controlling adjustment of the transmit diversity parameter, and s is a function of weighted values of the feedback signals (FB i); and the function of weighted values of the feedback signals (FB i) is given by: s = ∑ i = 1 2 N 1 + N 2 F B i. W i wherein 2(N 1 +N 2) is the number of feedback signals (FBi), FB i are said feedback signals, and W i are weights being a function of a difference between values (φ i) of the transmit diversity parameter at time slots i and a nominal value (φ nominal) thereof. perturbing in the transmitter a transmit diversity parameter from its nominal value at a perturbation rate by modulating the transmit diversity parameter with respect to the nominal value in a first direction for at least said first component; receiving from the receiver feedback signals (FB i) according to a communication protocol, the feedback signals including feedback information relating to the perturbed signals as received at said receiver; and based at least on said feedback information, adjusting at the transmitter the nominal value of the transmit diversity parameter by preserving the nominal value or by increasing or decreasing the nominal value by a step size (Δφ) determined by a fractional scaling function ( f) of weighted values (s) of the feedback signals wherein: said scaling function ( f) is given by: f s = { b a s, − a ≤ s ≤ a b, s > a − b, s < − a wherein a and b are parameters controlling adjustment of the transmit diversity parameter, and s is a function of weighted values of the feedback signals (FB i); and the function of weighted values of the feedback signals (FB i) is given by: s = ∑ i = 1 2 N 1 + N 2 F B i. W i wherein 2(N 1 +N 2) is the number of feedback signals (FBi), FB i are said feedback signals, and W i are weights being a function of a difference between values (φ i) of the transmit diversity parameter at time slots i and a nominal value (φ nominal) thereof. said scaling function ( f) is given by: f s = { b a s, − a ≤ s ≤ a b, s > a − b, s < − a wherein a and b are parameters controlling adjustment of the transmit diversity parameter, and s is a function of weighted values of the feedback signals (FB i); and the function of weighted values of the feedback signals (FB i) is given by: s = ∑ i = 1 2 N 1 + N 2 F B i. W i wherein 2(N 1 +N 2) is the number of feedback signals (FBi), FB i are said feedback signals, and W i are weights being a function of a difference between values (φ i) of the transmit diversity parameter at time slots i and a nominal value (φ nominal) thereof.