Mobile phones and modern hearing aids comprise advanced digital signal processing techniques as well as coding algorithms.
From a functional point of view, digital hearing devices and mobile phones are approaching each other. In both types of device, similar or even identical algorithms can be found such as echo, reverberation and feedback control, noise reduction, intelligibility enhancement, artificial bandwidth extension, and binaural processing with two or more microphones.
Actual hearing aids include digital audio receivers and transmitters, not only for communication and entertainment, but also for binaural directional processing. State-of-the-art mobile phones offer new speech-audio compression schemes for the emerging HD-telephone services. They are also equipped with two (or more) microphones for the purpose of speech enhancement. It is not too big a step to realize hearing aid features as apps on smart phones. Further evolution might lead us to binaural mobile telephony, augmenting speech with ambient and spatial information - a preferred solution for audio conferencing, for example.
Despite these similarities, the signal conditions and the processing constraints are quite different: with respect to the coherence of signals, the complexity of algorithms, power consumption, and latency, for example. Synergies and distinctions of the corresponding signal processing and coding algorithms will be discussed. Design constraints and solutions will be presented by examples.