Method and apparatus for medium access control from integrated services packet-switched satellite networks

• US 6,449,267 B1
• Filed: 05/25/1999
• Issued: 09/10/2002
• Est. Priority Date: 02/24/1999
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Connors, Dennis P.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Nguyen, Simon
• Application Number:
  US09/318,227
• Time in Patent Office: 1,204 Days
• Field of Search: 370/321, 370/322, 370/347, 370/348, 370/437, 370/468, 455/450-453, 455/509
• US Class Current: 370/347
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

A method, apparatus, article of manufacture, and a memory structure for communicating data from a first node to a second node has been described. The method comprises the steps of receiving input data at the first node, transmitting a resource request having a resource metric from the first node to an allocating agent, receiving an allocation of resource units according to the resource metric, the resource units comprising at least one DAMA channel resource metric and at least one RA channel resource unit, queuing the input data into the DAMA channel buffer, dequeuing input data from the DAMA channel buffer into the RA channel buffer according to a comparison between a predicted transmission delay and a delay threshold, and transmitting the dequeued input data in the RA channel buffer via the RA resource units. The article of manufacture comprises a data storage device tangibly embodying instructions to perform the method steps described above. The apparatus comprises a receiver for receiving input data, a DAMA channel buffer for accepting the input data, a resource unit request module, operatively coupled to the transmitter and the receiver, the resource unit request module for generating a resource request metric when indicated by an information rate of the input data, and for receiving an allocation of resource units via the receiver, and a channel selection module, for dequeuing input data from the DAMA channel buffer to an RA channel buffer according to a predicted channel delay and a delay threshold.

Claims

1. A method of communicating input data from a first node to a second node via a communication link having a plurality of resource units, comprising the steps of:

transmitting a resource request having a resource metric from the first node to an allocating agent;

receiving an allocation of resource units according to the resource metric, the resource units comprising at least one demand assigned multiple access (DAMA) resource unit and at least one random access (RA) resource unit;

queuing the input data into a DAMA channel buffer; and

dequeuing the input data from the DAMA channel buffer to an RA channel buffer according to a comparison between a predicted transmission delay and a delay threshold.

2. The method of claim 1, wherein the resource request is transmitted from the first node when indicated by an information rate of the input data.

3. The method of claim 1, wherein the resource request comprises an information rate determined as a time-windowed average of a bit rate of the input data.

4. The method of claim 3, wherein the resource metric is the time-windowed average of the input data.

5. The method of claim 3, wherein the input data is received at the first node in data packets and the time windowed average of the input data rate is computed by performing the steps of:

measuring a size of received data packet;

accumulate the measured size of the received data packets for a time window T_c; and

determining time-windowed average of the input data according to the accumulated measured size of the received data packets and the time window T_c.

6. The method of claim 1, wherein:

the communication link is a TDMA communication link and the DAMA resource units and the RA resource units are time slots; and

the input data is dequeued from the DAMA buffer to the RA buffer in a first-in-first out order.

7. The method of claim 1, wherein the step of dequeuing the input data from the DAMA channel buffer to an RA channel buffer comprises the steps of:

computing a DAMA channel delay (DD);

computing a RA channel delay (RD); and

dequeuing the input data from the DAMA channel buffer to the RA channel buffer if the DAMA channel delay is greater than the delay threshold and the RA channel delay is less than the DAMA channel delay.

8. The method of claim 7, wherein the step of computing a DAMA channel delay (DD) comprises the steps of:

determining a length of the input data queued into the DAMA channel buffer; and

estimating the transmission delay for the input data most recently queued in the DAMA channel buffer from an estimate of the communication link resource units available to the first node and a length of the input data queued in the DAMA channel buffer.

9. The method of claim 7, wherein the input data comprises a plurality of data packets including a most recent queued data packet and at least one less recent queued data packet, and the step of computing a DAMA channel delay comprises the step of estimating the transmission delay for the most recent queued data packet in the DAMA channel buffer from a sum of the expected time delays for each of the less recent queued data packets in the DAMA channel buffer.

10. The method of claim 7, wherein the step of determining the RA channel delay (RD) comprises the steps of:

determining an amount of the input data in the RA channel buffer; and

determining the RA channel delay (RD) from the amount of the input data in the RA channel buffer and the capacity of the RA channel buffer.

11. An apparatus for communicating input data to a second node via a communication link having a plurality of resource units, comprising:

a receiver for receiving the input data;

a demand assigned multiple access (DAMA) channel buffer for accepting the input data;

resource unit request module, operatively coupled to a transmitter and the receiver, the resource unit request module for generating a resource request metric and for receiving an allocation of resource units via the receiver; and

a channel selection module, for dequeuing the input data from the DAMA channel buffer to a random access (RA) channel buffer according to a comparison between a predicted channel delay and a delay threshold.

12. The apparatus of claim 11, wherein the resource unit request module comprises a flow measure module for computing the information rate of the input data as a time-windowed average of the input data.

13. The apparatus of claim 11, wherein the channel selection module comprises:

a DAMA channel delay estimator for generating an estimated DAMA channel delay;

a RA channel delay estimator for generating an estimated RA channel delay; and

a dequeuing module for dequeuing input data from the DAMA channel buffer to the RA channel buffer when a DAMA channel delay is greater than a delay threshold and the RA channel delay is less than the DAMA channel delay.

14. An apparatus for communicating inout data from a first node to a second node via a communication link having a plurality of resource units, comprising:

means for receiving the input data at the first node;

means for transmitting a resource request having a resource metric from the first node to an allocating agent;

means for receiving an allocation of resource units according to the resource metric, the resource units comprising at least one demand assigned multiple access (DAMA) resource unit and at least one random access (RA) resource unit;

means for queuing the input data into a DAMA channel buffer;

means for dequeuing the input data from the DAMA channel buffer to an RA channel buffer according to a comparison between a predicted transmission delay and a delay threshold; and

means for transmitting dequeued input data in the RA channel buffer via the RA resource units.

15. The apparatus of claim 14, wherein the resource request is transmitted from the first node when indicated by an information rate of the input data.

16. The apparatus of claim 14, wherein the resource request comprises an information rate determined as a time-windowed average of a bit rate of the input data.

17. The apparatus of claim 16, wherein the resource metric is the time-windowed average of the input data.

18. The apparatus of claim 16, wherein the input data is received at the first node in data packets and the time windowed average of the input data rate is computed by a input data flow measurement module having:

means for measuring a size of received data packet;

means for accumulating the measured size of the received data packets for a time window T₀; and

means for determining time-windowed average of the input data according to the accumulated measured size of the received data packets and the time window T₀.

19. The apparatus of claim 18, wherein the means for dequeuing the input data from the DAMA channel buffer to an RA channel buffer comprises:

means for computing a DAMA channel delay (DD);

means for computing a RA channel delay (RD); and

means for dequeuing the input data from the DAMA channel buffer to the RA channel buffer if the DAMA channel delay is greater than the delay threshold and the RA channel delay is less than the DAMA channel delay.

20. The apparatus of claim 19, wherein the means for computing a DAMA channel delay (DD) comprises:

means for determining a length of the input data queued into the DAMA channel buffer; and

means for estimating the transmission delay for the input data most recently queued in the DAMA channel buffer from an estimate of the communication link resource units available to the first node and a length of the input data queued in the DAMA channel buffer.

21. The apparatus of claim 19, wherein the input data comprises a plurality of data packets including a most recent queued data packet and at least one less recent queued data packet, and the means for computing a DAMA channel delay comprises means for estimating the transmission delay for the most recent queued data packet in the DAMA channel buffer from a sum of the expected time delays for each of the less recent queued data packets in the DAMA channel buffer.

22. The apparatus of claim 19, wherein the means for determining the RA channel delay (RD) comprises:

means for determining an amount of the input data in the RA channel buffer; and

means for determining the RA channel delay (RD) from the amount of the input data in the RA channel buffer and the capacity of the RA channel buffer.

23. A program storage device, readable by a computer, tangibly embodying at least one program of instructions executable by the computer to perform method steps for communicating input data from a first node to a second node via a communication link having a plurality of resource units, the method steps comprising the steps of:

transmitting a resource request having a resource metric from the first node to an allocating agent;

receiving an allocation of resource units according to the resource metric, the resource units comprising at least one demand assigned multiple access (DAMA) resource unit and at least one random access (RA) resource unit;

queuing the input data into a DAMA channel buffer; and

dequeuing the input data from the DAMA channel buffer to an RA channel buffer according to a comparison between a predicted transmission delay and a delay threshold.