Reserving time periods for communication on power line networks

• US 20060198387A1
• Filed: 03/03/2005
• Published: 09/07/2006
• Est. Priority Date: 03/03/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Yonge, Lawrence W. III, Katar, Srinivas
• Granted Patent: US 7,636,370 B2
• Time in Patent Office: Days
• US Class Current: 370/437
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 12/2803 Home automation networks
• CPC Class Codes: H04L 12/2836 Protocol conversion between an external network and a home network controlling appliance services of a home automation network from a device located outside the home and the home network H04L12/2818; protocol conversion H04L69/08; adaptation of digital video signals for transport over a specific home network H04N7/24
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 2012/2843 Mains power line

Abstract

Methods of operating in a network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period. At least some of the stations use a first CSMA network protocol having certain characteristics (e.g., some transmissions have a format that includes a start of frame delimiter (SOF), a payload, and an end of frame delimiter (EOF), wherein the SOF and EOF each contain sufficient information to permit a station receiving only one of the SOF and EOF to determine the start of a priority resolution period). And at least some stations use a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol. The second protocol may have various characteristics configured to achieve coexistence with the first protocol (e.g., transmissions that have a format that includes an SOF but not an EOF).

Claims

1. A method of operating in a network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions have a format that includes a start of frame delimiter (SOF), a payload, and an end of frame delimiter (EOF), wherein the SOF and EOF each contain sufficient information to permit a station receiving only one of the SOF and EOF to determine the start of a priority resolution period;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes transmissions that have a format that includes an SOF but not an EOF.

2. The method of claim 1 wherein the second network protocol comprises a CSMA protocol.

3. The method of claim 1 wherein the second network protocol comprises a TDMA protocol.

4. The method of claim 1 wherein the transmissions of the second protocol have the effect of reserving a reserved time period during which stations following the first protocol will not transmit.

5. The method of claim 4 wherein the reserved time period extends into the time normally occupied by the EOF according to the first CSMA network protocol.

6. The method of claim 5 wherein the station transmitting the SOFs without an EOF uses the reserved time period to transmit a payload.

7. The method of claim 5 wherein stations other than the station transmitting the SOF without an EOF transmit during the reserved time period.

8. The method of claim 4 wherein one or more stations operating in the second protocol transmits a series of SOFs, each without an EOF, to reserve a series of reserved time periods during which stations following the first protocol will not transmit.

9. The method of claim 4 wherein the reserved time period extends into a time gap between the EOF and the start of the priority resolution period.

10. The method of claim 1 wherein the transmissions using the first CSMA network protocol and the second network protocol have a format that includes an SOF specifying that no response delimiter is expected.

11. The method of claim 4 wherein the transmissions using the first CSMA network protocol have a format that includes an SOF capable of specifying that a response delimiter is expected, and the reserved time period extends beyond the normal time period of the EOF into a time gap between the EOF and the response delimiter.

12. The method of claim 10 wherein, even though the SOF specifies that no response delimiter is expected, at least some transmissions using the second protocol provide a response delimiter during approximately the time period normally occupied by the EOF.

13. The method of claim 4 wherein the transmissions using the first CSMA network protocol have a format that includes an SOF with a contention control field for specifying that stations with a lower channel access priority than the transmitting channel should not contend during the next priority resolution period, and wherein the reserved time period can extend through the completion of the priority resolution period by using an SOF with a contention control field set to specify that stations with a lower channel access priority should not contend.

14. The method of claim 13 wherein the reserved time period extends up to a maximum of about 1.695 milliseconds.

15. The method of claim 13 wherein one or more stations operating in the second protocol transmit a series of SOFs, each without an EOF, to reserve a series of reserved time periods during which stations following the first protocol will not transmit.

16. The method of claim 13 wherein the transmissions using the first CSMA network protocol assume that the channel access priority of a transmission is the highest possible if an EOF specifying the channel access priority is not received.

17. The method of claim 13 wherein the transmissions using the first CSMA network protocol have a format that includes an SOF capable of specifying that a response delimiter is expected, and by using an SOF that specifies a response delimiter the reserved time period can be further extended by the time associated with the expected response.

18. The method of claim 17 wherein the reserved time period extends up to a maximum of about 1.695 milliseconds.

30. The method of claim 4 wherein the medium comprises a power line within a building.

31. The method of claim 4 wherein the medium comprises a power line accessing a building.

34. The method of claim 4, 11, 12, 13, 17, 19, 22, 23, 24, or 32 wherein the medium comprises a power line medium.

38. The method of claim 4, 11, 12, 13, 17, 19, 22, 23, 24, or 32 wherein stations following the second protocol use a preamble that is recognized as a preamble by the first protocol.

19. A method of operating in a CSMA network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions comprise a response delimiter that includes one or more contention control parameters that can be set to specify that other stations should not contend during the next priority resolution period;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes transmissions that comprise a response delimiter in which the contention control parameters are set to specify that other stations should not contend during the next priority resolution period,

wherein the transmissions of the second protocol have the effect of reserving a reserved time period during which stations following the first protocol will not transmit at least through the completion of the priority resolution period.

20. The method of claim 19 wherein the reserved time period extends up to a maximum of about 1.695 milliseconds.

21. The method of claim 19 wherein the contention control parameters comprise a contention control field and a channel access priority field, wherein the transmissions using the second protocol have the channel access priority field set to the maximum possible value and the contention control field set to specify that only stations with a higher channel access priority field may contend during the next priority resolution period.

22. A method of operating in a CSMA network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions comprise a response delimiter, followed by a period in which no information is transmitted, followed by the priority resolution period;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes transmissions that comprise a response delimiter followed by a short payload occupying the period during which no information is transmitted in the first protocol.

23. A method of operating in a CSMA network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions have a format that includes a start of frame delimiter (SOF), a payload, and an end of frame delimiter (EOF), wherein the SOF and EOF each contain sufficient information to permit a station receiving only one of the SOF and EOF to determine the start of a priority resolution period, and wherein the SOF can specify that a response delimiter is expected;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes transmissions that have a format that includes an SOF but not an EOF, with the SOF specifying that a response delimiter is expected,

wherein the transmissions of the second protocol have the effect of reserving a reserved time period during which stations following the first protocol will not transmit at least through the time normally occupied by the EOF and the response delimiter in the first protocol.

24. A method of operating in a CSMA network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions comprise a start of frame delimiter (SOF), a payload, and an end of frame delimiter (EOF), wherein the EOF may specify whether a response delimiter is expected;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes transmissions that comprise an EOF without a preceding SOF and payload,

wherein the transmissions of the second protocol have the effect of reserving a reserved time period following the EOF, during which stations following the first protocol will not transmit.

25. The method of claim 24 wherein the EOF specifies that a response delimiter is not expected, and the reserved time period following the EOF extends to the start of the priority resolution period.

26. The method of claim 24 wherein the EOF specifies that a response delimiter is expected, and the reserved time period following the EOF extends to the start of the response delimiter.

27. The method of claim 26 wherein the reserved time period following the EOF extends to the start of the priority resolution period, and includes the period normally occupied by the response delimiter.

28. The method of claim 24 wherein the EOF of the first protocol includes one or more contention control parameters that can be set to specify that other stations should not contend during the next priority resolution period, and wherein the EOF used in the second protocol is set to specify that other stations should not contend during the next priority resolution period, wherein the reserved time period following the EOF can extend through the completion of the priority resolution period.

29. The method of claim 28 wherein the EOF specifies that a response delimiter is expected and the reserved time period following the EOF can include the time normally occupied by the response.

32. A method of operating in a network in which a plurality of stations communicate over a shared medium and contend for access during a priority resolution period, comprising

providing a first CSMA network protocol in which at least some transmissions have a format that includes at least one delimiter containing one or more fields in which one or more specific values are to appear, and wherein the first protocol calls for a station to wait for a period of time without transmitting if it receives a transmission in which information appearing in the one or more fields is not one of the specific values;

providing a second network protocol capable of coexisting with the first protocol, so that stations may communicate using either the first or second protocol, wherein the second protocol includes certain transmissions that have a format that includes information other than the specific values in locations corresponding to the one or more fields of the first protocol, wherein the effect of the certain transmissions is to prevent stations following the first protocol from transmitting for at least the period of time

33. The method of claim 32 wherein the at least one delimiter comprises at least one frame control field.

35. The method of claim 32 wherein the at least one delimiter comprises a start of frame (SOF) delimiter that contains at least one frame control field.

36. The method of claim 32 wherein the information other than the specific values is information whose only function is to cause stations following the first protocol to wait for the time period.

37. The method of claim 32 wherein the information other than the specific values is information that serves both to convey information to another station following the second protocol and to cause stations following the first protocol to wait for the time period.

39. The method of claim 32 wherein the effect of the certain transmissions is to cause stations following the first protocol to behave as if they have received an invalid delimiter.