In this paper the author presents a low complexity speech coding scheme similar to the ITU-T G.722 standard that also works on a sample basis to achieve a low latency. In the literature, asynchronous connection links (ACL) were proposed for carrying real-time voice. The author proposes to use the standard synchronous Bluetooth speech transmission (SCO link) to transmit the lowpass part of the speech signal (50 Hz - 4 kHz). In addition, some side information is transmitted via an ACL link. This information can be used at the receiver side to reconstruct the highpass part of the speech signal (4 kHz - 8 kHz) from the lowpass signal. This approach is backward compatible to the present Bluetooth standard and can be implemented with currently available Bluetooth chips. Furthermore, it also avoids transcoding for the lowpass part of the speech signal. The author's approach is therefore a hierarchical speech codec, where the asynchronously transmitted side information improves the audio fidelity at the receiver. In the next section the author briefly discusses the different available Bluetooth link types. In section 3 and section 4 he presents the encoding and decoding of his bandwidth extension approach, respectively. Some results and concluding comments are given in section 6.
Wideband bluetooth speech transmission for hands-free car kits
2009
4 Seiten, 4 Bilder, 1 Tabelle, 7 Quellen
Aufsatz (Konferenz)
Englisch
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