External jitter buffer in a packet voice system

Abstract

A packet voice communication system having a jitter buffer external to a voice processor. The jitter buffer stores voice packets received from a packet network. The voice processor processes the voice packets from the jitter buffer. A jitter buffer processor may place an indicator in each voice packet it holds. The indicator can indicate a length of time the voice packet was held. The rate at which packets come from the jitter buffer may be based upon the indicator, a higher rate if holding times are high and a slower rate if low. The voice processor can store the voice packets in a packet queue prior to processing the voice packets. The rate voice packets come to the voice processor may be based upon how full the packet queue is, a higher rate if the packet queue is relatively empty and a slower rate if relatively full.

Therefore, at least the following is claimed: 
     
         1 . A packet voice communication system comprising:
 an external jitter buffer external to a voice processor and adapted to receive voice packets from a network and to hold the received voice packets, wherein the external jitter buffer is further adapted to place an indicator in each of the packets it holds, the indicator being indicative of how long the voice packet was held in the external jitter buffer; and   a voice processor adapted to synchronously retrieve voice packets from the external jitter buffer and to process the retrieved voice data packets.   
     
     
         2 . The system of  claim 1  wherein the voice processor is adapted to adjust the rate at which it retrieves voice packets from the external jitter buffer based upon a value of the indicator. 
     
     
         3 . The system of  claim 2  wherein the voice processor comprises a jitter buffer manager adapted to retrieve voice packets from the external jitter buffer and wherein the jitter buffer manager is adapted to adjust the rate at which it retrieves voice packets from the external jitter buffer based upon a value of the indicator. 
     
     
         4 . The system of  claim 1  wherein the indicator indicates a length of time the voice packet was held in the external jitter buffer. 
     
     
         5 . The system of  claim 1  wherein the indicator indicates a time that the voice packet arrived at the external jitter buffer. 
     
     
         6 . The system of  claim 1  wherein the indicator indicates how many voice packets are held in the jitter buffer. 
     
     
         7 . The system of  claim 1  wherein the voice packets received by the external jitter buffer are part of a packet sequence according to which the packets are intended to be played out, and wherein the indicator indicates a span of time represented by the earliest and latest packets of a sequence that are held in the external jitter buffer and all packets inbetween the earliest and latest packets in the sequence, regardless of whether the inbetween packets are held in the jitter buffer. 
     
     
         8 . The system of  claim 1  wherein the external jitter buffer is adapted to place the indicator in a header of each voice packet. 
     
     
         9 . The system of  claim 1  wherein the external jitter buffer comprises a processor that is separate from the voice processor. 
     
     
         10 . A method of operating a packet voice communication system, comprising:
 (a) receiving a voice packet from a network;   (b) holding the received voice packet in an external jitter buffer external to a voice processor;   (c) placing an indicator in the voice packet, the indicator being indicative of how long the voice packet was held in the external jitter buffer;   (d) retrieving the voice packet, including the indicator, from the external jitter buffer; and   (e) processing the voice packet with the voice processor.   
     
     
         11 . The method of  claim 10  further comprising:
 (f) adjusting the rate at which voice packets are retrieved from the external jitter buffer based upon a value of the indicator. 
 
     
     
         12 . The method of  claim 10  wherein the indicator indicates a length of time the voice packet was held in the jitter buffer. 
     
     
         13 . The method of  claim 10  wherein the indicator indicates a time that the voice packet arrived at the external jitter buffer. 
     
     
         14 . The method of  claim 10  wherein the indicator indicates how many voice packets are held in the jitter buffer. 
     
     
         15 . The method of  claim 10  wherein placing step (c) comprises placing an indicator in the header of the voice packet, the indicator being indicative of how long the voice packet was held in the external jitter buffer. 
     
     
         16 . The method of  claim 10  wherein the external jitter buffer comprises a processor that is separate from the voice processor. 
     
     
         17 . A packet voice communication system comprising:
 a voice processor adapted to receive voice packets in a packet queue and to process the received voice packets, an external jitter buffer external to the voice processor and adapted to receive voice packets from a network, hold the received voice packets, and synchronously provide the voice packets to the voice processor, wherein the voice processor is adapted to notify the external jitter buffer of how many voice packets are in the voice processor's packet queue.   
     
     
         18 . The system of  claim 17  wherein the external jitter buffer is adapted to adjust the rate at which it provides voice packets to the voice processor based upon how many voice packets are in the voice processor's packet queue. 
     
     
         19 . The system of  claim 17  wherein the external jitter buffer comprises a processor that is separate from the voice processor.