MAP-TRIGGERED DUMP OF PACKETS IN SATELLITE COMMUNICATION SYSTEM

• US 20090290532A1
• Filed: 03/20/2009
• Published: 11/26/2009
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Wu, Xiao, Connors, Dennis Patrick, Deveau, James Edward, Jaska, Kristi Ann, Freier, Matthew John
• Granted Patent: US 8,107,410 B2
• Time in Patent Office: Days
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• CPC Class Codes: H04B 7/2123 Variable assignment, e.g. demand assignment

Abstract

Upstream information arriving through a user terminal in a satellite link is efficiently scheduled through a modified Demand Assigned Multiple Access (DAMA) algorithm such that data packets arriving at the user terminal are concatenated to form a larger frame for transmission and the concatenated packet is held in a first queue disposed ahead of a second queue, where the data in the second queue cannot be modified (typically a hardware queue), sufficient to allow the second queue to be emptied. In a specific embodiment, all packets arriving at the user terminal since a prior piggyback request are concatenated so that all currently known packets (up to a preselected limit) are accounted for by each succeeding piggyback request. Since it is desirable to concatenate all packets that arrive at the user terminal since the last piggyback request, the piggyback request according to the invention covers all currently known packets (up to the preselected limit) in the user terminal. The held-back packets are released or dumped to the second queue by a trigger operative according to a map, the map being a grant allocation schedule. This mechanism handles instances where the second queue is not able to handle all known packets.

Claims

1. A method performed by a satellite user terminal, the method comprising:

receiving data packets; and

scheduling an upstream transmission of the received data packets by (i) concatenating the received data packets in a first queue to form a concatenated packet for transmission, and (ii) releasing the concatenated packet from the first queue to a second queue when the second queue is empty.

2. The method according to claim 1, wherein all packets arriving at the user terminal since a prior piggyback request are concatenated so that all currently known packets are accounted for by each succeeding piggyback request.

3. The method according to claim 1, wherein packets are released to the second queue according to a trigger caused by receipt of a transmit map at the user terminal.

4. The method according to claim 1, wherein packets are released from the first queue to the second queue upon receipt at the user terminal of a valid map containing a viable transmit opportunity element for the user terminal.

5. The method according to claim 4, further including a virtual queue, said virtual queue for holding a description of the size of the data in the second queue for use in determination of the viable transmit opportunity.

6. The method according to claim 1, wherein said first queue is a software queue and said second queue is a hardware queue, said second queue containing unmodifiable data.

7. The method according to claim 1, further including the step of:

introducing a phantom packet into the first queue when the second queue is completely drained in order to minimize usage of a contention-associated request channel.

8. A method for scheduling upstream information arriving through a user terminal in a satellite communication link comprising:

concatenating data packets arriving at a first queue at the user terminal to form a concatenated frame for transmission; and

holding the concatenated frame as a packet in the first queue disposed ahead of a second queue until the last instant to allow the second queue to empty.

9. A satellite user terminal comprising:

a receiver configured to receive data packets; and

a processor, communicatively coupled to the receiver, configured to schedule an upstream transmission of the received data packets by (i) concatenating the received data packets in a first queue to form a concatenated packet for transmission, and (ii) releasing the concatenated packet from the first queue to a second queue when the second queue is empty.

10. The satellite user terminal according to claim 9, said transmitter being being further configured to release the concatenated packet from the first queue to the second queue using a transmit map having been received at the satellite user terminal.

11. The satellite user terminal according to claim 9, said transmitter being being further configured to release the concatenated packet from the first queue to the second queue using a valid map containing a viable transmit opportunity element for the satellite user terminal having been received at the satellite user terminal.

12. A satellite user terminal, comprising:

means for receiving packets;

means communicatively coupled with said packet receiving means for concatenating the received packets at a first queue to form a concatenated packet for transmission; and

means communicatively couple to said concatenating means for releasing the concatenated packet from the first queue to a second queue only upon emptying of the second queue.