Data structures with amortized control overhead and methods and networks using the same

• US 7,433,370 B1
• Filed: 02/10/2003
• Issued: 10/07/2008
• Est. Priority Date: 02/10/2003
• Status: Expired due to Fees

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Tymes, LaRoy
• Primary Examiner(s): Chan; Wing F.
• Assistant Examiner(s): Tsegaye; Saba
• Application Number:
  US10/361,246
• Time in Patent Office: 2,066 Days
• Field of Search: 370/336, 370/345, 370/349, 370470-476, 370/498, 370/496
• US Class Current: 370/474
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method and data structure for transmitting data in a networked system having a shared transmission medium that includes generating a plurality of virtual packets each containing information for delivery to at least one selected terminal in the networked system via the shared medium and generating a map field having control information for controlling the delivery of the virtual packets. The method and data structure also include forming a physical packet for transmission across the shared transmission medium, the physical packet including a control field and the plurality of virtual packets such that overhead associated with the control field and medium access is amortized over the plurality of virtual packets.

Claims

1. A method of transmitting data in a networked system including a shared transmission medium, comprising:

generating a plurality of virtual packets each containing information for delivery to at least one selected terminal in the networked system via the shared medium;

generating a control field having control information for controlling the delivery of the virtual packets; and

forming a physical packet for transmission across the shared transmission medium, the physical packet including the control field and the plurality of virtual packets such that overhead associated with the control field and medium access is amortized over the plurality of virtual packets, the physical packet having a map field for allowing a receiving terminal to identify and decode only those virtual packets within the physical packets addressed to the receiving terminal and including a plurality of entries each controlling the delivery of a corresponding one of the virtual packets, each entry including a first field for identifying the selected terminal for delivery of the corresponding virtual packet, a second field indicating a size of the corresponding virtual packet, and a third field for reconstructing a larger data structure from the corresponding virtual packet.

2. The method of claim 1, wherein the control field comprises a preamble and a header.

3. The method of claim 1, wherein the map field further comprises:

a preamble for detecting the map field within the physical packet;

a fourth field indicating a number of entries in the map field; and

a fifth field indicating a location within the physical packet of a first virtual packet.

4. The method of claim 1, wherein each virtual packet further includes error correction information.

5. The method of claim 1, wherein the physical packet further comprises a header decodable by selected terminals on the network.

6. The method of claim 5, wherein the header comprises a standard packet header for transmitting a physical packet from a transmitting terminal to itself.

7. The method of claim 5, wherein the header comprises a standard packet header for transmitting a physical packet to a special address.

8. The method of claim 1, wherein forming the physical packet comprises forming the physical packet with a plurality of map fields, a number of the plurality of map fields selected in response to a noise level in the network.

9. The method of claim 1, further comprising selectively generating an acknowledge signal from the selected terminal in response to delivery of a corresponding set of correctly received virtual packets.

10. The method of claim 9, further comprising retransmitting a set of unacknowledged virtual packets in a second physical packet including a control field and a plurality of virtual packets.

11. The method of claim 1, further comprising transmitting the physical packet across the shared medium, first and second ones of the virtual packets within the physical packet being transmitted at respective first and second data rates.

12. A method of transmitting data across a shared medium comprising:

generating a data structure including a physical packet for carrying data across the shared transmission medium, the physical packet including a plurality of virtual packets carrying data payloads and at least one map field having control information for controlling the delivery of the virtual packets to selected terminals coupled to the shared medium such that a time overhead associated with the header, preamble and shared transmission medium access is amortized across the physical packet; and

generating the at least one map field for allowing a receiving terminal to identify and decode only those virtual packets within the physical packet addressed to the receiving terminal and including a plurality of entries each controlling the delivery of a corresponding one of the virtual packets, each entry including a first field for identifying the selected terminal for delivery of the corresponding virtual packet, a second field indicating a size of the corresponding virtual packet, and a third field for reconstructing a larger data structure from the corresponding virtual packet.

13. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the physical packet further comprises a physical header decodable by substantially all the terminals coupled to the shared medium.

14. The method of claim 12, wherein generating the data structure comprises generating the data structure such that each virtual packet further includes an associated checksum field.

15. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the physical packet further comprises a header.

16. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the physical packet further comprises a preamble.

17. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the virtual packets are distributed within the physical packet to minimize latency during delivery of virtual packets to the selected terminals.

18. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the at least one map field comprises a plurality of map fields, a number of the plurality of map fields selected to increase detection of at least one map field in a noisy environment across the shared medium.

19. The method of claim 12, wherein generating the data structure comprises generating the data structure such that the at least one map field comprises:

a preamble for detecting the map field;

a field identifying a location of a reference virtual packet within the physical packet;

a field identifying a number of virtual packets within the physical packet;

an entry for delivering a corresponding virtual packet to a receiving terminal; and

an error detection field.

20. A network, comprising:

a shared medium; and

a plurality of information processing terminals coupled to the shared medium, a first one of the terminals transmitting information to at least a second one of the terminals via the shared medium and operable to;

generate a plurality of virtual packets each containing information for delivery to the at least one second terminal;

generate a map field having control information for controlling the delivery of the virtual packets to at least one second terminal such that the second terminal identifies and decodes only data virtual packets addressed to the second terminal and, the map field including an entry for each of the plurality of virtual packets, wherein each entry includes first field for identifying the at least one second terminal, a second field indicating a size of the corresponding virtual packet; and

a third field for reconstructing a larger data structure from the corresponding virtual packet; and

form a physical packet for transmission across the shared transmission medium to at least one second terminal, the physical packet including the map field and the plurality of virtual packets such that overhead associated with the physical packet is amortized over the plurality of virtual packets.

21. The network of claim 20, wherein the shared medium comprises a hard-wired infrastructure.

22. The network of claim 20, wherein the shared medium comprises a wireless transmission medium.

23. The network of claim 20, wherein at least a portion of the network complies with ANSI/IEEE Std. 802.11 and selected enhancements thereto.

24. A method of communicating in a shared medium system, comprising:

generating a plurality of virtual packets each containing information for transmission;

generating associated control information including a map field portion having an entry corresponding to each of the plurality of virtual packets, wherein each entry includes a first field for identifying at least one terminal, a second field indicating a size of the corresponding virtual packet, and a third field for reconstructing a larger data structure from the corresponding virtual packet, wherein the map field portion allows a receiving terminal to identify and decode only those virtual packets addressed to the receiving terminal and;

transmitting a physical packet including the plurality of virtual packets and the associated control information;

receiving the physical packet at a plurality of terminals communicating via the shared medium;

decoding the associated control information at a selected one of the terminals; and

processing at least one of the plurality of virtual packets at the selected one of the terminals in accordance with the associated control information.

25. The method of claim 24, further comprising discarding the physical packet at a second selected one of the terminals not operable to decode the associated control information.

26. The method of claim 25, wherein the selected one of the terminals is operable to decode a header portion of the associated control information and the second selected one of the terminals is inoperable to decode the header portion of the associated control information.

27. The method of claim 24, further comprising acknowledging receipt of each of at least one of the virtual packets by the selected one of the terminals.

28. The method of claim 24, wherein the selected one of the terminals processes at least one of the plurality of virtual packets having a corresponding data rate.

29. The method of claim 24, wherein the selected one of the terminals is operable to decode the map field portion of the associated control information to identify at least one of the virtual packets.