First generation wireless link systems for portable listening devices, such as hearing aids, have typically been based on fixed transmitted power between the devices. The transmitter current is, e.g. in the production phase, (conservatively) aligned to the minimum current with which the system always can achieve binaural communication, taking into account component tolerances, different operational distances between devices because of variation in head sizes, etc. The overhead in current in a particular setup represents a waste of power for those devices.
EP 1 860 914 A1 describes a method of operating a hearing assistance system comprising establishing a wireless link between a hearing device and a remote device for transmitting signals from the remote device to the hearing device, and operating the system in a base mode and an interference mode, and detecting whether a source of radio frequency signals interfering with the wireless link is present in the vicinity of the hearing device, the interfering source having a transmission power changing according to a predictable scheme between low power regimes and high power regimes. In the interference mode, the transmission of the signals from the remote device to the hearing device is synchronized to the detected power scheme of the interfering signals in such a manner that the signals are transmitted only during the low power regimes.
US 2008/0226107 A1 describes a transmission method and a corresponding system for inductive transmission, in which the receiver returns an item of quality information relating to the received signal back to the transmitter. The transmission power of the transmitter is then dynamically varied as a function of the item of quality information.