Modifying a signal according to a diversity parameter adjustment includes accessing scan parameter values, where a scan parameter describes a scan process. The scan parameter values include diversity parameter vectors, where a diversity parameter vector has a diversity parameter value for each of one or more diversity parameters. The scan process is performed by repeating the following for each diversity parameter vector: modifying a signal according to the diversity parameter values of the diversity parameter vector, where the signal is transmitted from a modifying communication device to a feedback communication device; and receiving a feedback signal reflecting feedback information describing the signal as received by the feedback communication device.