Bandwidth Efficient Mixed Pseudo Analogue-Digital Speech Transmission Carsten Hoelper and Peter Vary {hoelper,vary}@ind.rwth-aachen.de ETSI Workshop on Speech and Noise in Wideband Communication 22.-23. May 2007, Sophia Antipolis, France Institut für Nachrichtengeräte und Datenverarbeitung Prof. Dr.-Ing. P. Vary
Outline Carsten Hoelper 2 Introduction Mixed Pseudo Analogue-Digial (MAD) Transmitter Channel & Receiver Speech Transmission Summary & Conclusions
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Introduction Carsten Hoelper 3 Analogue AM speech transmission: - low channel bandwidth - highly sensitive to additive noise Digital speech transmission: - robust channel coding against transmission errors - higher bandwidth - higher complexity - maximum quality defined by the speech codec design Mixed Pseudo Analogue-Digital (MAD) speech transmission: - combine the advantages of both paradigms
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Introduction Carsten Hoelper 4 Principle of MAD Transmission: Digital Information C (Parameters) A/D s Linear Prediction a i r g Power Equalization r n MAD Transmission Time-Discrete, Quasi-Continuous-Amplitude
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Bit Rate R d Carsten Hoelper 5
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Calculation and Quantization of LP coefficients with original AMR-GSM modules (Narrowband and Wideband) Bit Rate R d Carsten Hoelper 6
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Bit Rate R d Carsten Hoelper 7
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Bit Rate R d within each 5ms subframe Carsten Hoelper 8
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Bit Rate R d Carsten Hoelper 9
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Mixed Pseudo Analogue-Digital Transmission LP Analysis a i VQ ^a i index(a i ) Sample Rate R a s a A/D s 1-A(z) 1-A(z/γ) r Gain g x Q g^ index(g) Channel Coder r n = r. g^ c Bit Rate R d Very low complexity (e.g. no codebook search) Carsten Hoelper 10
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions MAD Transmission: Channel & Receiver Carsten Hoelper 11 Samples Bits Pulseshaping Root Raised Cosine + AWGN Symbol Rate R a +R d Matched Filter Root Raised Cosine DE r n c Viterbi Decoder x 1/g Parameter Decoder 1-A(z/γ) 1-A(z) a i D/A s a Channel Receiver Root Raised Cosine: Transmission Bandwidth:
Introduction MAD Transmitter Channel & Receiver Speech Transmission Narrowband Speech Transmission Carsten Hoelper 12 Summary & Conclusions Channel bandwidth of narrowband transmission (NB)
Introduction MAD Transmitter Channel & Receiver Speech Transmission Narrowband Speech Transmission Carsten Hoelper 13 Summary & Conclusions Narrowband speech: 300Hz 3.4kHz audio bandwidth Es/N0 [db] Es: Energy per coded bit / per sample
Introduction MAD Transmitter Channel & Receiver Speech Transmission Wideband Speech Transmission Carsten Hoelper 14 Summary & Conclusions Channel bandwidth of wideband transmission (WB)
Introduction MAD Transmitter Channel & Receiver Speech Transmission Wideband Speech Transmission Carsten Hoelper 15 Summary & Conclusions Wideband speech: 50Hz 7kHz audio bandwidth Es/N0 [db] Es: Energy per coded bit / per sample
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Summary & Conclusions Carsten Hoelper 16 Mixed Pseudo Analogue-Digital (MAD) speech and audio transmission is an alternative concept of high quality transmission with low complexity, e.g. for wireless microphones and cordless telephones MAD speech transmission outperforms narrowband and wideband AMR w.r.t. speech quality, transmission bandwidth, and complexity Not being based on a model of speech production, MAD is suitable for speech and audio transmission
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions Summary & Conclusions Carsten Hoelper 17 Thank you for your attention
Introduction MAD Transmitter Channel & Receiver Speech Transmission Summary & Conclusions References for Further Information Carsten Hoelper 18 Introduction of MAD Transmission: MAD Audio Transmission: MAD Transmission with 2-Dimensional Modulation: