Media flow method for transferring real-time data between asynchronous and synchronous networks

• US 7,126,957 B1
• Filed: 03/07/2002
• Issued: 10/24/2006
• Est. Priority Date: 03/07/2002
• Status: Expired due to Fees

• Current Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Original Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Inventors: Isukapalli, Sridhar G. Sharma, Pandey, Pradeep, Shaver, Matthew D., Schneider, Neal A., Tsztoo, Gary
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): ROBERTS, BRIAN S
• Application Number:
  US10/094,232
• Time in Patent Office: 1,692 Days
• Field of Search: 370/415, 370/416, 370/395.61, 370/418
• US Class Current: 370/412
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9023 for implementing a jitter-buffer
• CPC Class Codes: H04L 49/9031 Wraparound memory, e.g. overrun or underrun detection

Abstract

A system for transmitting real-time data between an asynchronous network (104) and a synchronous network (106) is disclosed. A method (100) may include an ingress path (102) for transmitting data from an asynchronous system (104) to a synchronous system (106), and an egress path (108) for transmitting data from a synchronous system (106) to an asynchronous system (104). An ingress path (102) may include a packet receiver (110) and write to synchronous system (112) steps. An egress path (108) may include read from synchronous system (114), packetizer (116), and packet transmitter (118) steps.

Claims

1. A method for transmitting data between two systems, comprising the steps of:

reading a time indication including reading a timestamp value from a predetermined field from received data packets that include a plurality of data samples each assigned to different predetermined channel;

checking a status value of each predetermined channel of the received data packet;

if the status value of the predetermined channel is active,

generating a jitter buffer address from a jitter buffer size, the predetermined channel, and the time indication, calculating a jitter buffer offset value by multiplying the channel by a jitter buffer size and

copying the data sample of the predetermined channel from the received packet to the generated jitter buffer address; and

periodically reading a plurality of data samples from the jitter buffer corresponding to a predetermined sequence of channels and writing said plurality of data samples to at least one synchronous buffer wherein the jitter buffer is a circular buffer.

2. The method of claim 1, wherein:

checking the status value of each predetermined channel of the received data packet includes looking up a channel value in a valid index according to a channel identification value for each sample in the received packet and a trunk identification value common to each sample in the received packet.

3. The method of claim 1, wherein:

generating the jitter buffer address for the active predetermined channel further includes combining the jitter buffer offset address with at least a portion of the timestamp value and wherein

periodically reading the plurality of data samples from the jitter buffer includes

reading a first channel value at a first address, and

incrementing the address by the same amount to arrive at each sample in the sequence.

4. The method of claim 1, wherein:

periodically reading the plurality of data samples from the jitter buffer includes reading the sequence to one synchronous buffer on even time stamp values and to another synchronous buffer on odd time stamp values.

5. The method of claim 1, further including:

the received data packets include simplex packets having a data sample assigned to a single predetermined channel and multiplex packets that include the data samples assigned to different predetermined channels;

checking a predetermined field of the received packets for a multiplex indication;

if the predetermined field does not include a multiplex indication;

checking a status value of the predetermined channel of the received data packet;

if the status value of the predetermined channel is active,

generating a jitter buffer address from a jitter buffer size, the predetermined channel, and the time indication, and

copying the data sample of the predetermined channel from the received packet to the generated jitter buffer address.

6. A method for transmitting data between two systems, comprising the steps of:

receiving data from a first system that includes a plurality of data samples each assigned to a channel value corresponding to a predetermined time slot;

reading a time indication associated with a first system;

generating an offset value from the time indication;

periodically, for each channel

generating a packet buffer address from at least a buffer size value and the offset value, and

for a valid data sample, writing the data assigned to the predetermined time slot to the packet buffer address;

checking the status of a plurality of bins that each include a number of channel values;

if a bin has a ready status

organizing the data samples corresponding to the channel values of the bin into a sequential order, and

reading the data samples for the channels of a bin according to the sequential order.

7. The method of claim 6, wherein:

receiving data from a first system includes receiving data from a time division multiplex system at a synchronous buffer that includes a plurality of sequential addresses, each corresponding to a predetermined time slot.

8. The method of claim 6, wherein:

checking the status of the plurality of bins includes determining if a predetermined amounts of time has passed since data for the bins was transmitted, the predetermined amount of time for one bin being different from that of at least one other bin.

9. The method of claim 6, wherein:

generating a packet buffer address includes generating a first packet buffer address from at least the offset and generating subsequent packet buffer addresses by adding buffer size value to the previous packet address.

10. The method of claim 6, wherein:

organizing the data samples corresponding to the channel values of the bin includes generating at least one descriptor that includes a pointer to the addresses of the data samples corresponding to the channel values of the bin.

11. The system of claim 10, wherein:

each descriptor includes pointers to a predetermined number of data samples; and

organizing the data samples further includes chaining a plurality of descriptors when the number of channels in a bin exceeds the predetermined number of data values for one descriptor.

12. The system of claim 10, wherein:

reading the data samples for the channels of a bin includes interrupting a direct memory access process and providing a first descriptor to the direct memory access process.

13. The system of claim 10, wherein:

organizing the data samples further includes forming at least one queue entry that includes a pointer to a first descriptor of at least one group of descriptors.

14. The system of claim 13, wherein:

organizing the data samples further includes forming at least one queue index that includes a pointer to at least one queue entry.

15. A method of transmitting multiple channel data between an asynchronous system and a synchronous system, comprising the steps of:

a) upon receiving a packet of data from the asynchronous system

determining if the packet of data includes data samples for multiple channels,

if a packet includes data samples for multiple channels

determining a channel value for each data sample, and

if the channel value is valid, storing the data sample for the channel according to at least the channel value and a time indication associated with the packet of data;

b) periodically checking status values for a sequence of channels, and if a status value for a channel is valid, writing the stored data sample for the channel to at least one buffer according to at least the channel value;

c) periodically storing out-going channel data samples from the synchronous system according to at least a local time indication;

d) periodically checking the status of bins that represent collections of channels for out-going channels, and for bins having a ready status, queuing out-going channel data for the bin according to channel status information; and

e) periodically transmitting queued out-going channel data.

16. The method of claim 15, wherein:

the step a) further includes

if a packet does not include data samples for multiple channels

determining the channel value for a single data sample, and

if the channel value is valid, storing the data sample for the channel according to the channel value and a time indication associated with the packet of data.

17. The method of claim 15, wherein:

the step b) further includes if a status value for a channel is not valid, writing replacement data for the channel to the buffer according to at least the channel value.

18. The method of claim 15, wherein:

the step b) further includes writing the stored data sample for the channel to one of a plurality of buffers according to time indication associated with the received packet.

19. The method of claim 15, wherein:

in step a), storing the data samples for the channel according to at least the channel value includes generating a memory address from the channel value, a buffer size value, and at least a portion of the time indication associated with the received packet.

20. The system of claim 15, wherein:

in step b), writing the stored data sample for the channel to at least one buffer includes generating a memory address from a base address, a buffer size value, and at least a portion of the local time indication.

21. The method of claim 15, wherein:

in step d) at least two bins reach the ready status at differing rates.

22. The method of claim 15, wherein:

step d) forming at least one list that includes a sequence of entries for accessing out-going channel data.

23. The method of claim 22, wherein:

step d) the at least one list includes a list of descriptors that indicate locations where out-going channel data are stored.

24. The method of claim 22, wherein:

step d) the at least one list includes a queue index that defines the extent of at least one queue entry, the at least one queue entry indicating the locations where out-going channel data are stored.

25. The method of claim 22, wherein:

step d) the at least one list includes a plurality of queue entries, each queue entry indicating the locations where out-going channel data are stored for a common destination location.