Long preamble and duty cycle based coexistence mechanism for power line communication (PLC) networks

1. A method comprising:

using a power line communication (PLC) device to communicate using a first technology on a channel in a PLC network by:

detecting a coexistence preamble that is common to the first technology and to a second technology and that is not followed by a native preamble associated with the first technology;

in response to the coexistence preamble, waiting a duration before attempting a transmission;

determining whether a threshold back-off duration has been reached; and

in response to the threshold back-off duration being reached, transmitting a long coexistence preamble sequence that includes a plurality of repetitions of a preamble such that the long coexistence preamble sequence has a duration at least as long as a largest packet associated with the PLC network.

2. The method of claim 1 , further comprising transmitting a data frame on the channel after transmitting the long coexistence preamble sequence.

3. The method of claim 1 , wherein the duration is defined as a predetermined number N of coexistence Extended Interframe Space (cEIFS) durations for the PLC network, wherein N is an integer.

4. The method of claim 1 , wherein the long coexistence preamble sequence is a first long coexistence preamble sequence, the method further comprising:

determining that a second long coexistence preamble sequence has been transmitted on the channel; and

in response to the first long coexistence preamble sequence, delaying transmission of a third long coexistence preamble sequence on the channel for at least a threshold back-off duration.

5. The method of claim 1 , wherein the first technology and the second technology are from a group consisting of: G3, PRIME, IEEE P1901.2 FCC-low band, IEEE P1901.2 CEN-A, IEEE P1901.2 FCC, and G.hnem.

6. The method of claim 1 , wherein the preamble that is repeated in the long coexistence preamble sequence includes a synchronization symbol.

7. The method of claim 6 , wherein the synchronization symbol includes an IEEE P1901.2 synchronization symbol.

8. The method of claim 1 further comprising:

monitoring occupancy of the channel;

determining when the occupancy of the channel by a given technology of the first technology and the second technology exceeds a network duty cycle time; and

in response to the occupancy by the given technology exceeding the network duty cycle time, backing off from the channel for a duty cycle Extended Interframe Space (dcEIFS) duration.

9. A method comprising:

receiving, by a communication device, a coexistence preamble that is common to a first technology for communicating over a channel of a network and to a second technology for communicating over the channel of the network, wherein the coexistence preamble is not followed by a native preamble associated with the first technology;

in response to the coexistence preamble not being followed by the native preamble associated with the first technology, performing a backoff before attempting a transmission using the first technology, wherein the backoff is a first backoff;

monitoring occupancy of the channel by the communication device;

determining when the occupancy of the channel by the first technology exceeds a network duty cycle time;

in response to the occupancy by the first technology exceeding the network duty cycle time, performing a second backoff before transmission using the first technology; and

in response to a threshold number of backoffs being performed, transmitting, by the communication device, a coexistence preamble sequence that has a duration at least as long as a largest packet associated with the network.

10. The method of claim 9 , wherein the coexistence preamble sequence includes a plurality of repetitions of a preamble.

11. The method of claim 9 , wherein the preamble of the coexistence preamble sequence includes a synchronization symbol.

12. The method of claim 11 , wherein the synchronization symbol includes an IEEE P1901.2 synchronization symbol.

13. The method of claim 9 further comprising transmitting a data frame on the channel by the communication device after transmitting the coexistence preamble sequence.

14. The method of claim 9 , wherein the backoff is for a duration defined by an integer number of Extended Interframe Space (cEIFS) durations.

15. The method of claim 9 , wherein the first technology and the second technology are from a group consisting of: G3, PRIME, IEEE P1901.2 FCC-low band, IEEE P1901.2 CEN-A, IEEE P1901.2 FCC, and G.hnem.

16. A communication device comprising:

a receiver configured to couple to a network;

a processor; and

a non-transitory memory coupled to the processor, wherein the non-transitory memory stores program instructions executable by the processor that, when executed, cause the communication device to:

receive a coexistence preamble associated with a first technology and a second technology for communication over a channel of the network;

determine that the coexistence preamble is not followed by a native preamble associated with the first technology;

in response to the coexistence preamble not being followed by the native preamble, perform a backoff before attempting a transmission using the first technology, wherein the backoff is a first backoff;

monitor occupancy of the channel by the communication device;

determine when the occupancy of the channel by the first technology exceeds a network duty cycle time;

in response to the occupancy by the first technology exceeding the network duty cycle time, perform a second backoff before transmission using the first technology; and

in response to a threshold number of backoffs being performed, transmit a coexistence preamble sequence that has a duration at least as long as a largest packet associated with the network.

17. The communication device of claim 16 , wherein the non-transitory memory stores further program instructions that, when executed, cause the communication device to transmit a data frame on the channel after transmission of the coexistence preamble sequence.

18. The communication device of claim 16 , wherein the coexistence preamble sequence includes a plurality of repetitions of a synchronization symbol.

19. The communication device of claim 18 , wherein the synchronization symbol includes an IEEE P1901.2 synchronization symbol.