Advanced speech-audio processing in mobile phones and hearing aids: Synergies and distinctions

Summary form only given. 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 devices similar or partly 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 and they are equipped with two (or more) microphones for the purpose of speech enhancement. Thus, it is not a too big step to realize hearing aid features as apps on smart phones. The further evolution might lead us to binaural mobile telephony, providing ambient and spatial information - a preferred solution for audio conferencing, for example. Despite these relations, the signal conditions and the processing constraints are quite different, e.g., with respect to coherence of signals, complexity of algorithms, coding-noise shaping for binaural processing, power consumption, and latency. Synergies and distinctions of the corresponding signal processing and coding algorithms will be discussed. Design constraints and solutions will be presented by examples.