Power management in low power wireless link in a hearing aid system

A hearing aid system comprising a first hearing aid device and a mobile device, wherein each of the devices comprises a transmit unit and a receive unit for establishing a short range wireless link between the devices, wherein at least one of the devices comprises:

• a microphone configured to receive an acoustical audio signal,
• a signal processor configured to process an audio signal based on the acoustical audio signal, and
• first link quality estimating circuitry configured to determine a phase error of an information packet transmitted from the other device and received by the receive unit and determine a link quality signal based on the phase error, wherein the phase error is determined by averaging a phase error of multiple samples/bits of the information packet to obtain an average phase error for the information packet, and then averaging the average phase error for the information packet with average phase errors of multiple other information packets, and
• wherein the at least one of the devices is configured to transmit the link quality signal to the other device, and the other device is configured to determine the power level of the transmission of the information packet based on the link quality signal via a power controller comprised by the other device.