System And Method For A Guaranteed Delay Jitter Bound When Scheduling Bandwidth Grants For Voice Calls Via A Cable Network

Abstract

A system and method for guaranteeing a delay jitter bound when scheduling bandwidth grants for voice calls via a communication medium is provided. The method includes the steps of: determining the delay jitter bound; based on the determined delay jitter bound, dividing a packetization frame period into phases; assigning a voice call to one of the phases; and scheduling a bandwidth grant to the voice call during the assigned phase, thereby guaranteeing the delay jitter bound. The system includes a scheduler, where the scheduler determines the delay jitter bound, divides a packetization frame period into phases based on the determined delay jitter bound, assigns a voice call to one of the phases, and schedules a bandwidth grant to the voice call during the assigned phase, thereby guaranteeing the delay jitter bound. A dejitter buffer implements a way to provide zero jitter service, even though the packet transmission on the cable network has jitter, by delaying the packet and thus converting jitter into delay.

1 . A method for guaranteeing a delay jitter bound when scheduling transmission opportunities to constant bit rate data applications via a communication medium, including the steps of: 
 determining the delay jitter bound;    based on said determined delay jitter bound, dividing a packetization frame period into one or more phases;    assigning a constant bit rate data application to one of said phases; and    scheduling a transmission opportunity to said constant bit rate data application during said assigned phase, thereby guaranteeing the delay jitter bound.    
   
   
       2 . The method of  claim 1 , wherein said transmission opportunity is a bandwidth grant and said constant bit rate application is a voice call.  
   
   
       3 . The method of  claim 2 , wherein said step of scheduling includes the steps of: 
 determining whether said voice call is active; and    granting bandwidth to said voice call only when said voice call is active.    
   
   
       4 . The method of  claim 3 , wherein said step of scheduling further includes the step of granting bandwidth to non-voice data according to a fragmentation policy.  
   
   
       5 . The method of  claim 4 , wherein said fragmentation policy is a fixed region boundaries and strict fragmentation policy.  
   
   
       6 . The method of  claim 4 , wherein said fragmentation policy is a floating region boundaries and minimized fragmentation policy.  
   
   
       7 . The method of  claim 4 , wherein said fragmentation policy is a fixed region boundaries and best fit packet policy.  
   
   
       8 . The method of  claim 2 , further including the step of: 
 alternating the order of the grant of bandwidth to said voice call and non-voice data in adjacent phases of said one or more phases.    
   
   
       9 . The method of  claim 1 , wherein the communication medium is a cable network.  
   
   
       10 . The method of  claim 1 , wherein the communication medium is a wireless network.  
   
   
       11 . The method of  claim 1 , wherein the communication medium is the Internet.  
   
   
       12 . The method of  claim 1 , wherein the communication medium is a satellite network.  
   
   
       13 . The method of  claim 1 , wherein the communication medium is a fiber optic network.  
   
   
       14 . The method of  claim 1 , wherein one or more of said phases is further divided into sub-phases.  
   
   
       15 . The method of  claim 2 , further comprising the step of: 
 delaying the transmission of said bandwidth grant to ensure a zero delay jitter bound.    
   
   
       16 . A system for guaranteeing a delay jitter bound when scheduling transmission opportunities to constant bit rate data applications via a communication medium, comprising: 
 a scheduler, wherein said scheduler determines the delay jitter bound, wherein said scheduler divides a packetization frame period into one or more phases based on said determined delay jitter bound, wherein said scheduler assigns a constant bit rate data application to one of said phases, and wherein said scheduler schedules a transmission opportunity to said constant bit rate data application during said assigned phase, thereby guaranteeing the delay jitter bound.    
   
   
       17 . The system of  claim 16 , wherein said transmission opportunity is a bandwidth grant and said constant bit rate application is a voice call.  
   
   
       18 . The system of  claim 17 , wherein said scheduler determines whether said voice call is active, and wherein said scheduler grants bandwidth to said voice call only when said voice call is active.  
   
   
       19 . The system of  claim 18 , wherein said scheduler grants bandwidth to non-voice data according to a fragmentation policy.  
   
   
       20 . The system of  claim 19 , wherein said fragmentation policy is a fixed region boundaries and strict fragmentation policy.  
   
   
       21 . The system of  claim 19 , wherein said fragmentation policy is a floating region boundaries and minimized fragmentation policy.  
   
   
       22 . The system of  claim 19 , wherein said fragmentation policy is a fixed region boundaries and best fit packet policy.  
   
   
       23 . The system of  claim 17 , wherein one or more of said phases is further divided into sub-phases.  
   
   
       24 . The system of  claim 16 , wherein the communication medium is a cable network.  
   
   
       25 . The system of  claim 16 , wherein the communication medium is a wireless network.  
   
   
       26 . The system of  claim 16 , wherein the communication medium is the Internet.  
   
   
       27 . The system of  claim 16 , wherein the communication medium is a satellite network.  
   
   
       28 . The system of  claim 16 , wherein the communication medium is a fiber optic network.  
   
   
       29 . The system of  claim 16 , wherein said scheduler is implemented as a priority first-come first-served scheduler.  
   
   
       30 . The system of  claim 16 , wherein said scheduler is applied in a switch implementation.  
   
   
       31 . The system of  claim 16 , further comprising: 
 a dejitter buffer for delaying the transmission of a packet to an external system to ensure a zero delay jitter bound.    
   
   
       32 . The system of  claim 31 , wherein said external system is the Internet.  
   
   
       33 . The system of  claim 17 , wherein said scheduler alternates the order of the grant of bandwidth to said voice call and non-voice data in adjacent phases of said one or more phases.