Personal Hearing System 

The PHS is the software component of the PCS which performs individual processing of audio signals for the hearing impaired PCS user. Processed audio signals include both, environmental signals captured with microphones near the user's ears, and audio output of other PCS services. The functionality of the PHS is basically the same as that of a conventional hearing aid, except for some additional features:
l        Increased connectivity: The PCS provides many services, which can connect external sources with the PHS.
l        Advanced audio signal processing schemes: The performance and battery size of the central processing device allows for algorithms which otherwise would not run on conventional hearing aids.
l        Potential of production cost reduction: Usage of standard hardware might reduce production costs, if consumer headsets can be used (users with mild hearing loss).
 
The final PCS is designed to be integrated in a single, pocket size hardware (PDA or SmartPhone). The signal processing performance of the PHS will scale with the continuously growing performance of standard notebook computers, while the size of the PHS will shrink with the decreasing size and increasing portability of standard hardware. Depending on the wireless body area network (WBAN) delay properties, two signal processing architectures are possible:
l        WBAN delay is low (round-trip delay is below 5-15 ms): The audio signal of the headset microphones is transmitted to the PCS, and the processed signal is transmitted back to the headset.
l        WBAN delay is high (round-trip delay is above 5-15 ms): The audio signal of the headset microphones is transmitted to the PCS. On the PCS, the signal is analyzed using advanced signal analysis schemes, and control information is sent back to the headset, steering the filter algorithms.
 
The difference between these architectures concerns the algorithm implementation, and the requirements towards processing power in the native headset processing.