Leased line optimization and voice quality improvement in bandwidth constrained communication systems

Abstract

The present invention is embodied in a method an apparatus for reducing the number of leased E 1 lines needed to backhaul communication traffic in a satellite communication situation. The present invention receives and decompressed a satellite signal. A copy of the compressed signal is then encoded into the least significant bits (LSBs) of the decompressed signal. The decompressed signal having the embedded information may be routed to an international PSTN network over leased communications lines. However, the compressed information is extracted from the decompressed signal and sent across the E 1 lines, thereby conserving communication bandwidth and reducing the number of leased lines required. After passing through the E 1 lines the information is decompressed and connected to the international PSTN network. Alternatively, the decompressed signal having the embedded information may be distributed to local PSTN networks, which interpret decompressed signals. The degradation in voice quality of the decompressed signal due to the embedding of the compressed information in negligible.

What is claimed is:  
     
         1 . A gateway for transferring data representative of voice from a first location to a second location comprising: 
 a voice decoder for decompressing a compressed voice signal received from a satellite;    a voice packetizer and embedder for embedding the compressed signal within the decompressed signal; and    a transcoder for removing the embedded compressed signal from the decompressed signal and delivering the compressed signal to a communication line.    
     
     
         2 . The gateway of    claim 1   , wherein the transcoder comprises a voice packet detector for detecting the compressed signal within the decompressed signal.  
     
     
         3 . The gateway of    claim 2   , wherein the transcoder ( 136 ) further comprises a voice packet extractor and transmitter for removing the embedded compressed signal from the decompressed signal and for delivering the compressed signal to the communication line.  
     
     
         4 . The gateway station of    claim 1   , wherein the decompressed signal represents samples of an analog signal.  
     
     
         5 . The gateway station of    claim 4   , wherein the decompressed signal representing samples of an analog signal comprise least significant bits.  
     
     
         6 . The gateway station of    claim 5   , wherein the compressed signal is embedded in the decompressed signal by replacing the least significant bits of the decompressed signal with the compressed signal.  
     
     
         7 . The gateway station of    claim 1   , wherein the compressed signal has a data rate less than 8 kilobits per second.  
     
     
         8 . The gateway station of    claim 1   , wherein the decompressed signal has a data rate of 64 kilobits per second.  
     
     
         9 . A transcoder for transferring data representative of voice from a first communication line to a second communication line comprising: 
 a voice decoder for decompressing a compressed voice signal received from the first communication line; and    a linear to A-law format converter for converting the decompressed signal to an A-law format and for coupling the decompressed A-law format signals to the second communication line.    
     
     
         10 . The transcoder of    claim 4   , further comprising an A-law to linear format converter for converting signals received from the second communication line to a linear format; and 
 a voice encoder for compressing the linearly formatted signals and for coupling the compressed linearly formatted signals to the first communication line.    
     
     
         11 . The transcoder of    claim 10   , wherein the first communication line is a leased communication line and the second communication line is a telephone network.  
     
     
         12 . The gateway of    claim 1   , further comprising a voice mail system in communication with the voice packetizer and embedder, wherein the voice mail system ( 200 ) is used to store voice mail messages comprising a compressed signal embedded within a decompressed signal.  
     
     
         13 . A method for transferring data representative of voice from a first location to a second location comprising: 
 decompressing a compressed voice signal received from a satellite to create a decompressed signal;    embedding the compressed signal within the decompressed signal;    removing the embedded compressed signal from the decompressed signal; and    delivering the compressed signal to a communication line.    
     
     
         14 . The method of    claim 13   , wherein a transcoder performs the step of detecting the compressed signal within the decompressed signal.  
     
     
         15 . The method of    claim 14   , wherein the transcoder performs the step of removing the embedded compressed signal from the decompressed signal; and 
 delivering the compressed signal to the communication line.    
     
     
         16 . The method of    claim 13   , wherein the decompressed signal represents samples of an analog signal.  
     
     
         17 . The method of    claim 16   , wherein the decompressed signal representing samples of an analog signal comprise least significant bits.  
     
     
         18 . The method of    claim 17   , wherein the compressed signal is embedded in the decompressed signal by replacing the least significant bits of the decompressed signal with the compressed signal.  
     
     
         19 . The method of    claim 13   , wherein the compressed signal has a data rate less than 8 kilobits per second.  
     
     
         20 . The method of    claim 13   , wherein the decompressed signal has a data rate of 64 kilobits per second.  
     
     
         21 . A method for transferring data representative of voice from a first communication line to a second communication line comprising the steps of: 
 decompressing a compressed voice signal received from the first communication line;    converting the decompressed signal to an A-law format; and    coupling the decompressed A-law format signals to the second communication line.    
     
     
         22 . The method of    claim 21   , wherein the first communication line is a leased communication line and the second communication line is a telephone network.  
     
     
         23 . A method for storing data representative of voice comprising the steps of: 
 decompressing a compressed voice signal received from a satellite to create a decompressed signal;    embedding the compressed signal within the decompressed signal;    delivering the decompressed signal embedded with the compressed signal to a voice mail system; and    storing the decompressed signal embedded with the compressed signal in the voice mail system.