WO1999001941A1 - Device for transmitting a coded adpcm voice signal - Google Patents

Device for transmitting a coded adpcm voice signal Download PDF

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Publication number
WO1999001941A1
WO1999001941A1 PCT/ES1998/000161 ES9800161W WO9901941A1 WO 1999001941 A1 WO1999001941 A1 WO 1999001941A1 ES 9800161 W ES9800161 W ES 9800161W WO 9901941 A1 WO9901941 A1 WO 9901941A1
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WO
WIPO (PCT)
Prior art keywords
voice signal
differentially
bits
packets
error detection
Prior art date
Application number
PCT/ES1998/000161
Other languages
Spanish (es)
French (fr)
Inventor
Belén Ruiz Mezcua
Mariano Perez Abadia
Mª Isabel LOPEZ CARRILLO
Original Assignee
Alcatel Alsthom - Compagnie Generale D'electricite
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcatel Alsthom - Compagnie Generale D'electricite filed Critical Alcatel Alsthom - Compagnie Generale D'electricite
Priority to AU76552/98A priority Critical patent/AU7655298A/en
Publication of WO1999001941A1 publication Critical patent/WO1999001941A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
    • H04B14/06—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using differential modulation, e.g. delta modulation

Definitions

  • the present invention relates to the transmission of voice in a noisy environment, for example in a radio system with mobile terminals. More precisely, the invention relates to devices for attenuating the reception of received voice sequences, or replacing these voice sequences with comfort sequences, when the quality of said voice sequences is very weak for the user.
  • the word "mutmg" is used to define these techniques.
  • the document describes a muting solution that is applied to the PCM signal based on errors detected using error detection codes of the CRC type transmitted together with the ADPCM signal, however, the solution described in this document does not solve the problem of the occurrence of click noise that causes a disturbance, very unpleasant to the user, of the original voice signal for a long duration Although the described solution improves the subjective quality of the voice as it is received by the user, the initial disturbance is wide signed in time by the solution of this document.
  • a first objective of the invention is to propose a device for transmitting an ADPCM encoded voice signal that allows to increase the subjective quality of the voice as it is received by a user.
  • a second objective of the invention is to propose a receiving device of this ADPCM encoded voice signal as it is sent from the transmission device in order to retrieve a good ⁇ -voice signal of sub-objective quality.
  • a transmission device for transmitting successive packets of voice signal bits comprising differential encoding means for differentially encoding said speech signal bit packets is characterized in accordance with the invention because it comprises means for generating a code of error detection for each differentially coded voice signal bit packet, in order to detect errors in the transmission of said differentially coded voice signal packets in a remote receiving device.
  • a receiving device for receiving successive bit packets of differentially encoded voice signal from a device defined above is characterized in that it comprises means for detecting a error in a differentially encoded packet based on its associated error detection code, and means for applying a at least partial reception deactivation algorithm of the corresponding differentially decoded signal
  • FIG. 2 shows a receiving device according to the invention
  • FIG. 3 shows a data signal as transmitted from the device of figure 1 to the device of figure 2.
  • a differentially encoded voice signal transmission device comprises a PCM (Pulse Coding Moduiation) encoder 10, an ADPCM (Adaptive Differential Pulse Coding Modulation) 11 encoder, a circuit of Generation of error detection code 12 and a multiplexer 13.
  • the input signal S (t) is an analog voice signal as it is received from a microphone for example.
  • This signal S (t) is applied to an input of the PCM encoder 10 that samples this signal and transforms each sampling into a N bit word, N being for example equal to 8.
  • the resulting N bit word is applied to an input of the ADPCM encoder 11, well known in the state of the art, which produces a differentially encoded word.
  • the code produced by circuit 12 and the words produced by ADPCM encoder 11 are multiplexed in multipiexor 13 to produce a signal as shown in Figure 3.
  • This signal of Figure 3 alternatively comprises a differentially encoded word and a redundancy bit R of the total code for error detection.
  • R redundancy bit
  • the error detection code noted “RRRR”
  • the remote unit includes a demultipiexor 20, an error detection circuit 21, an ADPCM decoder 22 and a muting unit 23.
  • the signal received by the remote unit from the local unit is in the form of the signal shown in Figure 3.
  • the demultiplexer 20 applies the voice bits to the decoder 22, and both the voice bits D and the error detection bits R to the error detection circuit 21.
  • the unit 22 applies an algorithm that attenuates, that is partially deactivated, the reception of the decoded received voice sequence, or replaces this voice sequence with a comfort sequence, or carries out another treatment
  • any other type of more complex algorithm can be used in unit 23.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Theoretical Computer Science (AREA)
  • Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)

Abstract

The present invention relates to a transmission device for transmitting, for example by radio, packets of successive bits of a voice signal. The device comprises differential coding means (11) for coding differentially said bit packets of the voice signal, and is characterized in that it comprises means (12) for generating an error detection code (R) for each voice signal bit packet which is coded differentially in order to detect in a remote receiver device errors in the transmission of said packets of the voice signal which are coded differentially. Said error detection code takes into account only the most significant bits of said differentially coded packet.

Description

Dispositivo de transmisión de una señal de voz codificada Transmission device of an encoded voice signal
ADPCM.ADPCM
OBJETO DE LA INVENCIÓNOBJECT OF THE INVENTION
La presente invención se refiere a la transmisión de la voz en un entorno ruidoso, por ejemplo en un sistema de radiocomunicaciones con los terminales móviles. Más precisamente, la invención se refiere a dispositivos para atenuar la recepción de secuencias de voz recibidas, ó substituir estas secuencias de voz por secuencias de confort, cuando la calidad de dichas secuencias de voz está muy débil para el usuario. En literatura anglosajona, la palabra "mutmg" se usa para definir estas técnicas.The present invention relates to the transmission of voice in a noisy environment, for example in a radio system with mobile terminals. More precisely, the invention relates to devices for attenuating the reception of received voice sequences, or replacing these voice sequences with comfort sequences, when the quality of said voice sequences is very weak for the user. In Anglo-Saxon literature, the word "mutmg" is used to define these techniques.
ESTADO DE LA TÉCNICA El documento "Improved ADPCM voice transmission employing click noise detection scheme for TDMA-TDD systems" publicado en "The Fourth International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC93) - Yokohama, Japan, September 8-11, 1993' describe una solución para resolver el problema de la aparición de ruidos de "click noise" en una señal de voz recibida. El documento describe una solución de muting que se aplica a la señal PCM en función de errores detectados utilizando códigos de detección de error del tipo CRC transmitidos juntos con la señal ADPCM. Sin embargo, la solución descrita en este documento no resuelve el problema de la aparición de los ruidos de "click noise" que producen una perturbación, muy desagradable al usuario, de la señal de voz original durante una duración larga. Aunque la solución descrita mejora la calidad subjetiva de la voz tal como está recibida por el usuario, la perturbación inicial está amplificada en el tiempo por la solución de este documento.STATE OF THE TECHNIQUE The document "Improved ADPCM voice transmission employing click noise detection scheme for TDMA-TDD systems" published in "The Fourth International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC93) - Yokohama, Japan, September 8-11, 1993 'describes a solution to solve the problem of the occurrence of click noise in a received voice signal. The document describes a muting solution that is applied to the PCM signal based on errors detected using error detection codes of the CRC type transmitted together with the ADPCM signal, however, the solution described in this document does not solve the problem of the occurrence of click noise that causes a disturbance, very unpleasant to the user, of the original voice signal for a long duration Although the described solution improves the subjective quality of the voice as it is received by the user, the initial disturbance is wide signed in time by the solution of this document.
CARACTERIZACIÓN DE LA INVENCIÓNCHARACTERIZATION OF THE INVENTION
Un primer objetivo de la invención es proponer un dispositivo de transmisión de una señal de voz codificada ADPCM que permite aumentar la calidad subjetiva de la voz tal como está recibida por un usuario. Un segundo objetivo de la invención es proponer un dispositivo de recepción de esta señal de voz codificada ADPCM tal como está enviada desde el dispositivo de transmisión afín de recuperar una señal αe voz de buena calidad suibjetiva. Por consiguiente, un dispositivo de transmisión para transmitir paquetes de bitios sucesivos de señal de voz que comprende medios de codificación diferencial para codificar diferencialmente dichos paquetes de bitios de señal de voz, está caracterizado de acuerdo con la invención porque comprende medios para generar un código de detección de error para cada paquete de bitios de señal de voz codificado diferencialmente, al fin de detectar en un dispositivo de recepción distante errores en la transmisión de dichos paquetes de señal de voz codificados diferencialmente. dicho código de detección de error siendo calculado en función solamente de bitios los más significativos de dicho paquete codificado diferencialmente Un dispositivo de recepción para recibir paquetes de bitios sucesivos de señal de voz codificados diferencialmente desde un dispositivo definido arriba está caracterizado porque comprende medios para detectar un error en un paquete codificado diferenciaimente en función de su código de detección de error asociado, y medios para aplicar un algoritmo de desactivación de recepción al menos parcial de la señal descodificada diferenciaimente correspondienteA first objective of the invention is to propose a device for transmitting an ADPCM encoded voice signal that allows to increase the subjective quality of the voice as it is received by a user. A second objective of the invention is to propose a receiving device of this ADPCM encoded voice signal as it is sent from the transmission device in order to retrieve a good α-voice signal of sub-objective quality. Accordingly, a transmission device for transmitting successive packets of voice signal bits comprising differential encoding means for differentially encoding said speech signal bit packets is characterized in accordance with the invention because it comprises means for generating a code of error detection for each differentially coded voice signal bit packet, in order to detect errors in the transmission of said differentially coded voice signal packets in a remote receiving device. said error detection code being calculated based on only the most significant bits of said differentially encoded packet A receiving device for receiving successive bit packets of differentially encoded voice signal from a device defined above is characterized in that it comprises means for detecting a error in a differentially encoded packet based on its associated error detection code, and means for applying a at least partial reception deactivation algorithm of the corresponding differentially decoded signal
BREVE ENUNCIADO DE LAS FIGURASBRIEF STATEMENT OF THE FIGURES
Una explicación más detallada de la presente invención se da en la siguiente descripción basada en las figuras adjuntas en las cuales: - la figura 1 muestra un dispositivo de transmisión de acuerdo con la invención;A more detailed explanation of the present invention is given in the following description based on the attached figures in which: - Figure 1 shows a transmission device according to the invention;
- la figura 2 muestra un dispositivo de recepción de acuerdo con la invención; y- Figure 2 shows a receiving device according to the invention; Y
- la figura 3 muestra una señal de datos tal como está transmitida desde el dispositivo de la figura 1 hasta el dispositivo de la figura 2.- figure 3 shows a data signal as transmitted from the device of figure 1 to the device of figure 2.
DESCRIPCIÓN DE LA INVENCIÓNDESCRIPTION OF THE INVENTION
La invención se aplica, según un ejemplo, en un sistema de radiocomunicaciones con terminales móviles para la transmisión de voz entre una estación de base, ó unidad local, y un terminal móvil, o unidad distante. Sin embargo, la invención no esta limitada a esta aplicación y constituye una solución a la transmisión de voz en entorno ruidoso de manera general. De acuerdo con la invención y con referencia a la figura 1 , un dispositivo de transmisión de una señal de voz codificada diferencialmente comprende un codificador PCM (Pulse Coding Moduiation) 10, un codificador ADPCM (Adaptative Diferential Pulse Coding Modulation) 11 , un circuito de generación de código de detección de error 12 y un multiplexor 13. La señal de entrada S(t) es una señal de voz analógica tal como está recibida desde un micrófono por ejemplo. Esta señal S(t) se aplica a una entrada del codificador PCM 10 que muestrea esta señal y transforma cada muestreo en una palabra de N bitios, N siendo por ejemplo igual a 8. La palabra de N bitios resultante se aplica a una entrada del codificador ADPCM 11 , muy conocido en el estado de la técnica, que produce una palabra codificada diferencialmente. Cada palabra codificada diferencialmente comprende por ejemplo M=3 bitios D. Tres bitios D forman una palabra codificada diferencialmente y P=4 palabras codificadas diferencialmente sucesivas forman un paquete codificado diferencialmente. Para cada P=4 palabras de tres bitios codificadas diferencialmente, el circuito de generación de código de detección de error 12 produce un código de detección de error de P=4 bitios R. Este código está producido por un algoritmo memorizado en el circuito 12 y constituye un código de redundancia para la detección de error de transmisión hasta la unidad distante. El código producido por el circuito 12 y las palabras producida por el codificador ADPCM 11 están multiplexados en el multipiexor 13 para producir una señal tal como mostrada en la figura 3.The invention is applied, according to an example, in a radio system with mobile terminals for voice transmission between a base station, or local unit, and a mobile terminal, or unit distant. However, the invention is not limited to this application and constitutes a solution to voice transmission in noisy environment in general. In accordance with the invention and with reference to Figure 1, a differentially encoded voice signal transmission device comprises a PCM (Pulse Coding Moduiation) encoder 10, an ADPCM (Adaptive Differential Pulse Coding Modulation) 11 encoder, a circuit of Generation of error detection code 12 and a multiplexer 13. The input signal S (t) is an analog voice signal as it is received from a microphone for example. This signal S (t) is applied to an input of the PCM encoder 10 that samples this signal and transforms each sampling into a N bit word, N being for example equal to 8. The resulting N bit word is applied to an input of the ADPCM encoder 11, well known in the state of the art, which produces a differentially encoded word. Each differentially encoded word comprises for example M = 3 bits D. Three bits D form a differentially encoded word and P = 4 differentially successive encoded words form a differentially encoded packet. For each P = 4 differentially coded three-bit words, the error detection code generation circuit 12 produces an error detection code of P = 4 bits R. This code is produced by an algorithm memorized in circuit 12 and It constitutes a redundancy code for the detection of transmission error to the remote unit. The code produced by circuit 12 and the words produced by ADPCM encoder 11 are multiplexed in multipiexor 13 to produce a signal as shown in Figure 3.
Esta señal de la figura 3 comprende alternativamente una palabra codificada diferencialmente y un bitio de redundancia R del código total para la detección de error. Cuatros bitios de redundancia R sucesivos forman un código de detección de error asociado a las PxM=12 bitios de palabras sucesivos codificadas diferenciaimente que forman un paquete. De acuerdo con la invención, el código de detección de error, notado "RRRR", depende solamente de los bitios los más significativos de cada uno de las P=4 palabras codificadas diferencialmente. Por ejemplo, solo los dos primeros bitios de cada una de P=4 palabras codificadas diferencialmente sucesivas están utilizados para el calculo de un código de detección de error asociado "RRRR".This signal of Figure 3 alternatively comprises a differentially encoded word and a redundancy bit R of the total code for error detection. Four successive bits of R redundancy form an error detection code associated with PxM = 12 bits of successively coded successive words that form a packet. According to the invention, the error detection code, noted "RRRR", depends only on the most significant bits of each of the P = 4 differentially coded words. For example, only the first two bits of each of P = 4 differentially coded words successive ones are used for the calculation of an associated error detection code "RRRR".
Así, resulta que el numero de apariciones de "click noise" en la unidad distante es reducido debido al hecho que un error en los bitios los menos significativos no está detectado en la unidad distante porque el código de detección de error "RRRR" no tiene en cuenta estos bitios Ademas, este error no es importante porque está relativa solamente a uno o algunos del los bitios los menos significativos que no influyen mucho sobre la calidad de la voz. Con referencia a la figura 2, la unidad distante incluye un demultipiexor 20, un circuito de detección de error 21 , un descodificador ADPCM 22 y una unidad de muting 23.Thus, it turns out that the number of occurrences of "click noise" in the remote unit is reduced due to the fact that an error in the least significant bits is not detected in the remote unit because the error detection code "RRRR" does not have Keep in mind these bits In addition, this error is not important because it is only related to one or some of the least significant bits that do not greatly influence voice quality. Referring to Figure 2, the remote unit includes a demultipiexor 20, an error detection circuit 21, an ADPCM decoder 22 and a muting unit 23.
La señal recibida por la unidad distante desde la unidad local tiene la forma de la señal mostrada en la figura 3. El demultiplexor 20 aplica los bitios de voz al descodificador 22, y ambos ios bitios de voz D y los bitios de detección de error R al circuito de detección de error 21. El circuito de detección de error 21 reagrupa por P=4 los bitios R de la señal recibida y calcula un código de detección de error con los bitios D los mas significativos de los P=4 palabras de tres bitios codificadas diferencialmente correspondientes. El calculo de este código de detección de error utiliza el mismo algoritmo que el algoritmo utilizado en el circuito 12.The signal received by the remote unit from the local unit is in the form of the signal shown in Figure 3. The demultiplexer 20 applies the voice bits to the decoder 22, and both the voice bits D and the error detection bits R to the error detection circuit 21. The error detection circuit 21 regroups for P = 4 the bits R of the received signal and calculates an error detection code with the bits D the most significant of the P = 4 words of three differentially coded corresponding bits. The calculation of this error detection code uses the same algorithm as the algorithm used in circuit 12.
Si existe una correspondencia entre los P=4 bitios R reagrupados y los P=4 bitios calculados, resulta que el circuito de detección de error 21 no aplica ninguna señal en la entrada de la unidad de mutiπg 23. Por otro lado, si no hay correspondencia entre los P=4 bitios R reagrupados y los P=4 bitios calculados, resulta que el circuito de detección de error 21 aplica una señal en la entrada de la unidad de muting 23 que activa esta unidad 22. En este caso, la unidad 22 aplica un algoritmo que atenúa, es decir desactiva parcialmente, la recepción de la secuencia de voz recibida descodificada, ó substituye esta secuencia de voz por una secuencia de confort, ó lleva a cabo un otro tratamiento Esta secuencia de voz esta en la forma de P=4 palabras de bitios PCM que corresponden a las P=4 palabras de tres bitios codificadas diferencialmente. De acuerdo con la invención, todo otro tipo de algoritmo más complejo puede ser utilizado en la unidad 23. If there is a correspondence between the regrouped P = 4 bits and the calculated P = 4 bits, it turns out that the error detection circuit 21 does not apply any signal at the input of the mutiπg unit 23. On the other hand, if there is no correspondence between the P = 4 bits R regrouped and the P = 4 bits calculated, it turns out that the error detection circuit 21 applies a signal at the input of the muting unit 23 that activates this unit 22. In this case, the unit 22 applies an algorithm that attenuates, that is partially deactivated, the reception of the decoded received voice sequence, or replaces this voice sequence with a comfort sequence, or carries out another treatment This voice sequence is in the form of P = 4 words of PCM bits corresponding to P = 4 words of three differentially coded bits. According to the invention, any other type of more complex algorithm can be used in unit 23.

Claims

REIVINDICACIONES
1 - Dispositivo de transmisión para transmitir paquetes de bitios sucesivos de señal de voz que comprende medios de codificación diferencial (1 1 ) para codificar diferencialmente dichos paquetes de bitios de señal de voz, caracterizado porque comprende medios (12) para generar un código de detección de error (R) ) para cada paquete de bitios de señal de voz codificado diferenciaimente, al fin de detectar en un dispositivo de recepción distante errores en la transmisión de dichos paquetes de señal de voz codificados diferenciaimente, dicho código de detección de error (R) siendo calculado en función solamente de bitios los más significativos de dicho paquete codificado diferencialmente.1 - Transmission device for transmitting successive packets of voice signal bits comprising differential encoding means (1 1) for differentially encoding said voice signal bit packets, characterized in that it comprises means (12) for generating a detection code error (R)) for each packet of differentially encoded voice signal bits, in order to detect errors in the transmission of said differentially encoded voice signal packets, said error detection code (R ) the most significant of said differentially coded packet being calculated based on bits only.
2 - Dispositivo de recepción para recibir paquetes de bitios sucesivos de señal de voz codificados diferencialmente desde un dispositivo de acuerdo con la reivindicación 1 , caracterizado porque comprende medios (22) para detectar un error en un paquete codificado diferencialmente en función de su código de detección de error (R) asociado, y meαios (23) para aplicar un algoritmo de desactivación de recepción al menos oarcial αe la señal de voz descodificada diferencialmente correspondiente. 2 - Receiving device for receiving successive bit packets of differentially encoded voice signal from a device according to claim 1, characterized in that it comprises means (22) for detecting an error in a differentially encoded packet according to its detection code associated error (R), and meαios (23) to apply a reception deactivation algorithm at least oarcial αe the differentially decoded voice signal corresponding.
PCT/ES1998/000161 1997-07-02 1998-06-04 Device for transmitting a coded adpcm voice signal WO1999001941A1 (en)

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Citations (10)

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EP0422802A1 (en) * 1989-10-12 1991-04-17 Stc Plc Speech codec arrangement
US5073940A (en) * 1989-11-24 1991-12-17 General Electric Company Method for protecting multi-pulse coders from fading and random pattern bit errors
WO1993005502A1 (en) * 1991-09-05 1993-03-18 Motorola, Inc. Error protection for multimode speech coders
WO1993015502A1 (en) * 1992-01-28 1993-08-05 Qualcomm Incorporated Method and system for the arrangement of vocoder data for the masking of transmission channel induced errors
US5309443A (en) * 1992-06-04 1994-05-03 Motorola, Inc. Dynamic muting method for ADPCM coded speech
GB2291570A (en) * 1994-07-21 1996-01-24 Matsushita Electric Ind Co Ltd Adaptive error correcting device
WO1996009700A1 (en) * 1994-09-19 1996-03-28 Motorola Inc. Method and apparatus for error mitigating a received communication signal
US5517511A (en) * 1992-11-30 1996-05-14 Digital Voice Systems, Inc. Digital transmission of acoustic signals over a noisy communication channel
US5615222A (en) * 1994-02-04 1997-03-25 Pacific Communication Sciences, Inc. ADPCM coding and decoding techniques for personal communication systems

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988010035A1 (en) * 1987-06-04 1988-12-15 Motorola, Inc. Protection of energy information in sub-band coding
EP0422802A1 (en) * 1989-10-12 1991-04-17 Stc Plc Speech codec arrangement
US5073940A (en) * 1989-11-24 1991-12-17 General Electric Company Method for protecting multi-pulse coders from fading and random pattern bit errors
WO1993005502A1 (en) * 1991-09-05 1993-03-18 Motorola, Inc. Error protection for multimode speech coders
WO1993015502A1 (en) * 1992-01-28 1993-08-05 Qualcomm Incorporated Method and system for the arrangement of vocoder data for the masking of transmission channel induced errors
US5309443A (en) * 1992-06-04 1994-05-03 Motorola, Inc. Dynamic muting method for ADPCM coded speech
US5517511A (en) * 1992-11-30 1996-05-14 Digital Voice Systems, Inc. Digital transmission of acoustic signals over a noisy communication channel
US5615222A (en) * 1994-02-04 1997-03-25 Pacific Communication Sciences, Inc. ADPCM coding and decoding techniques for personal communication systems
GB2291570A (en) * 1994-07-21 1996-01-24 Matsushita Electric Ind Co Ltd Adaptive error correcting device
WO1996009700A1 (en) * 1994-09-19 1996-03-28 Motorola Inc. Method and apparatus for error mitigating a received communication signal

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