Method and system for transmitting data on a speech channel
AssigneeAlcatel
InventorsPierre Bonnard, Jean Varaldi
Life of this patent
Estimating the term…
Abstract
To transmit data over a mobile telephone speech channel a source encoder is replaced by a transcoder, a conversion table and/or a concatenation circuit in order to choose from the words produced by the source encoder the ones that are the most robust and which can without difficulty withstand speech synthesis followed by an inverse analysis to reconstitute streams of the bits of the data to be transmitted.
Claims27
A method of transmitting digital data between two telecommunication terminals on a speech channel, in particular a mobile telephone channel, via a telecommunication network comprising speech signal transcoders, the speech signals exchanged between said terminals being encoded and decoded in each terminal in accordance with a predetermined speech encoding scheme having a speech transmission format, wherein K-bit binary streams represent speech information over predetermined intervals, comprising:
- identifying bit configurations of said K-bit binary streams that are compatible with the transcoders (TRAU) of the telecommunication network, each of said identified bit configurations including at most K−L bits having values dependent on content of said digital data;
- transcoding the digital data into transcoded data with the speech transmission format using only said identified bit configurations, the transcoded data comprising K-bit words in which (K−L) bits have values dependent on the content of the digital data, and the remaining L bits have values independent of the content of the digital data, where both K and L are integers, K is greater than L, and L is greater than zero;
- transmitting the transcoded data over said telecommunications network;
- and
- decoding the transmitted transcoded data at the receiver,
- wherein said identifying the bit configurations of said binary streams that are compatible with the transcoders of the telecommunication network includes application of at least one of the following steps:
- excluding bits of the speech transmission format which are not protected by an error correcting code when transmitted as being used for said (K−L) bits having values dependent on the content of said digital data;
- excluding high variations in amplitude of pitch or energy values between successive K-bit binary streams;
- and
- excluding least significant bits of parameters within the speech transmission format as being used for said (K−L) bits having values dependent on the content of said digital data.
A device for transmitting digital data between two telecommunications terminals on a speech channel, in particular in a mobile telephone channel, via a telecommunications network comprising speech signals transcoders, the device including:
- a transcoder for transcoding the digital data into transcoded data with the speech transmission format, using only configurations of the speech encoding scheme which are compatible with the speech signal transcoders of the telecommunications network, and
- a switch for substituting, in the transmission, the transcoded data with the speech transmission format for a message delivered by a speech source encoder in the speech transmission format,
- wherein said speech transmission format uses K-bit binary streams representing speech information over predetermined intervals,
- wherein the transcoded data comprises K-bit words in which (K−L) bits have values dependent on content of the digital data and the remaining L bits have values independent of the content of the digital data, where both K and L are integers, K is greater than L, and L is greater than zero,
- and
- the transcoder excludes at least one of:
- bits of the speech transmission format which are not protected by an error correcting code when transmitted, as being used for said (K−L) bits dependent on the content of the digital data;
- high variations in amplitude of pitch or energy values between successive K-bit binary streams;
- and
- least significant bits of parameters within the speech transmission format, as being used for said (K−L) bits dependent on the content of the digital data.
A method of transmitting digital data between two telecommunication terminals on a mobile telephone speech channel, via a telecommunication network comprising speech signal transcoders, the speech signals exchanged between said terminals being encoded and decoded in each terminal in accordance with a predetermined speech encoding scheme having a speech transmission format wherein K-bit binary streams contain plural segments each representing a different aspect of speech information over predetermined intervals, said method comprising:
- for each of said segments, identifying a respective number of configurations of bits which can be used to represent the digital data, the identified configurations being compatible with the speech signal transcoders of said telecommunications network;
- transcoding the digital data into transcoded data with the speech transmission format, using only said identified configurations in each of said segments, the transcoded data comprising K-bit words in which (K−L) bits have values dependent on the content of the digital data and the remaining L bits have values independent of the content of the digital data, where both K and L are integers, K is greater than L, and L is greater than zero, and
- transmitting said transcoded data over said network.
Dependencies are inferred from the claim text.