Coexistence primitives in power line communication networks
Systems and methods for setting a carrier-sensing mechanism in a PLC node are disclosed. In a PLC standard, coexistence is achieved by having the nodes detect a common preamble and backing off by a Coexistence InterFrame Space (cEIFS) time period to help the node to avoid interfering with the other technologies. In one embodiment, a PHY primitive is sent from the PHY to the MAC know that there has been a preamble detection. A two-level indication may be used—one indication after receiving the preamble and other indication after decoding the entire frame. The MAC sets the carrier-sensing mechanism based on the preamble detection.
1. A device comprising:
a medium access control (MAC) layer; and
a physical (PHY) layer, the PHY layer configured to:
receive a data packet via a communication medium,
in response to detecting a first preamble in the data packet and a second preamble in the data packet, set a preamble indication primitive to a first value,
in response to detecting the first preamble and failing to detect the second preamble, set the preamble indication primitive to a second value different from the first value, and
provide the preamble indication primitive to the MAC layer.
2. The device of claim 1 , wherein the first preamble comprises M symbols that are common to a first communication protocol and to a second communication protocol, wherein M is a positive integer.
3. The device of claim 2 , wherein the M symbols comprise orthogonal frequency-division multiplexed (OFDM) symbols.
4. The device of claim 2 , wherein the M symbols comprise a chirp sequence.
5. The device of claim 2 , wherein the M symbols comprise a barker sequence.
6. The device of claim 2 , wherein the M symbols are M repeated symbols.
7. The device of claim 2 , wherein the M symbols comprise a SyncP symbol.
8. The device of claim 2 , wherein a size of the first preamble is as large as a maximum packet size supported by the first and second communication protocols.
9. The device of claim 2 , wherein the first communication protocol and the second communication protocol are from a group comprising: IEEE P1901.2, G3 power line communication standard, and PRIME power line communication standard.
10. The device of claim 1 , wherein the MAC layer is configured to:
in response to the preamble indication primitive being set to the first value, set a back-off interval to a first duration; and
in response to the preamble indication primitive being set to the second value, set the back-off interval to a second duration different from the first duration.
11. The device of claim 10 , wherein the MAC layer is configured to set the back-off interval by setting a network allocation vector (NAV).
12. The device of claim 11 , wherein the MAC layer is configured to check the NAV and allow an attempt by the device to send a frame via the communication medium only after the NAV reaches zero.
13. The device of claim 10 , wherein the first duration is a native extended interframe spacing (EIFS) value; and wherein the second duration is a coexistence extended interframe spacing (cEIFS) value.
14. The device of claim 10 , wherein the second duration is defined for a communication protocol associated with the second preamble.
15. The device of claim 1 , wherein the PHY layer is configured to provide the preamble indication primitive to the MAC layer before an entirety of the data packet is received.
16. The device of claim 1 , wherein the PHY layer is configured to attempt to detect the second preamble in response to detecting the first preamble.
17. The device of claim 1 , wherein the PHY layer is configured to receive the data packet via a power line.
18. The device of claim 1 , wherein the data packet comprises the first and second preambles, a frame control header (FCH), and a payload.
19. The device of claim 18 , wherein the PHY layer is configured to receive the second preamble after the first preamble, the FCH after the second preamble, and the payload after the FCH.
20. The device of claim 1 , wherein the device is a power line communication (PLC) device.