THE HANDS-FREE TELEPHONE PROBLEM - AN ANNOTATED-BIBLIOGRAPHY UPDATE

Providing means for a full-duplex hands-free telephone conversation is still a research topic in many communication and signal processing laboratories around the world. More than ninety publications mainly from the last two and a half years support this statement. The reason for these activities lies in the complexity of the problem : full-duplex telephone communication without hand-sets requires electronic replicas of the loudspeaker-enclosure-microphone systems used by the communicating parties. The impulse response of such a system is typically several 100 ms long and time varying. Therefore, the replica has to be adaptive while the adaptation is controlled by speech signals. Regarding these requirements the hands-free telephone problem may currently be considered as one of the most challenging signal processing problems. This bibliography supplements a bibliography composed approximately two and a half years ago [29]. Brief summaries are given on papers published since then.