Synchronization short inter-frame space (SIFS)
This disclosure provides methods, devices and systems for synchronizing an end of an exchange of frames during a transmission opportunity (TXOP) with a target synchronization time using a synchronization short inter-frame space (SynSIFS) before a transmission by a wireless communication device that controls the medium. The wireless communication device obtains control of the medium for the TXOP by completing a CCA procedure. An exchange of frames during the TXOP includes transmissions from the wireless communication device and responses from other devices while the wireless communication device controls the medium. A duration of the SynSIFS may be adjustable at a microsecond granularity. Accordingly, the wireless communication device may select a duration of the SynSIFS that allows alignment of the end of the exchange with the target synchronization time. The wireless communication device also may adjust a number of symbols in the transmission from the wireless communication device.
1. A method for wireless communication by an apparatus of a wireless communication device, comprising:
acquiring access to a wireless medium via a clear channel assessment (CCA) procedure; and
transmitting, to another device, a frame within an exchange of frames during a transmission opportunity (TxOP) of the wireless communication device after a duration of a synchronization short inter-frame space (SIFS), wherein the duration of the synchronization SIFS enables alignment of an end of the exchange with a target synchronization boundary.
2. The method of claim 1 , wherein the duration of the synchronization SIFS is between 13 microseconds and 19 microseconds.
3. The method of claim 1 , further including determining the duration of the synchronization SIFS.
4. The method of claim 3 , wherein determining the duration of the synchronization SIFS includes determining an offset between the target synchronization boundary and a symbol granularity of the exchange.
5. The method of claim 3 , wherein the frame from the wireless communication device is an acknowledgment after the synchronization SIFS that extends the exchange until the target synchronization boundary.
6. The method of claim 5 , wherein determining the duration of the synchronization SIFS includes subtracting a duration of the acknowledgment from a time of the target synchronization boundary to determine an end of the synchronization SIFS.
7. The method of claim 3 , wherein the exchange includes an acknowledgment from another device after the frame, and wherein determining the duration of the synchronization SIFS includes subtracting a duration of the frame, a predicted duration of the acknowledgment, and a predicted duration of a SIFS from a time of the target synchronization boundary to determine an end of the synchronization SIFS.
8. The method of claim 1 , further including adjusting a number of symbols in the frame from the wireless communication device such that a predicted end of the exchange is within one symbol length of the target synchronization boundary.
9. The method of claim 1 , further including determining the target synchronization boundary for the exchange.
10. The method of claim 1 , wherein the target synchronization boundary is an end of a second exchange on a second link.
11. The method of claim 1 , wherein the target synchronization boundary is a coordinated universal time (UTC) schedule.
12. A wireless communication device, comprising:
at least one modem;
at least one processor communicatively coupled with the at least one modem; and
at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to:
acquire access to a wireless medium via a clear channel assessment (CCA) procedure; and
transmit, to another device, a frame within an exchange of frames during a transmission opportunity (TxOP) of the wireless communication device after a duration of a synchronization short inter-frame space (SIFS), wherein the duration of the synchronization SIFS enables alignment of an end of the exchange with a target synchronization boundary.
13. The wireless communication device of claim 12 , wherein the duration of the synchronization SIFS is between 13 microseconds and 19 microseconds.
14. The wireless communication device of claim 12 , wherein the at least one processor is configured to determine the duration of the synchronization SIFS.
15. The wireless communication device of claim 14 , wherein the at least one processor is configured to determine an offset between the target synchronization boundary and a symbol granularity of the exchange.
16. The wireless communication device of claim 14 , wherein the frame from the wireless communication device is an acknowledgment after the synchronization SIFS that extends the exchange until the target synchronization boundary.
17. The wireless communication device of claim 16 , wherein the at least one processor is configured to determine subtract a duration of the acknowledgment from a time of the target synchronization boundary to determine an end of the synchronization SIFS.
18. The wireless communication device of claim 14 , wherein the exchange includes an acknowledgment from another device after the frame, and wherein the at least one processor is configured to subtract a duration of the frame, a predicted duration of the acknowledgment, and a predicted duration of a SIFS from a time of the target synchronization boundary to determine an end of the synchronization SIFS.
19. The wireless communication device of claim 12 , wherein the at least one processor is configured to adjust a number of symbols in the frame from the wireless communication device such that a predicted end of the exchange is within one symbol length of the target synchronization boundary.
20. The wireless communication device of claim 12 , wherein the at least one processor is configured to determine the target synchronization boundary for the exchange.
21. The wireless communication device of claim 12 , wherein the target synchronization boundary is an end of a second exchange on a second link.
22. The wireless communication device of claim 12 , wherein the target synchronization boundary is a coordinated universal time (UTC) schedule.
23. An apparatus for wireless communication by a wireless communication device, comprising:
means for acquiring access to a wireless medium via a clear channel assessment (CCA) procedure; and
means for transmitting, to another device, a frame within an exchange of frames during a transmission opportunity (TxOP) of the wireless communication device after a duration of a synchronization short inter-frame space (SIFS), wherein the duration of the synchronization SIFS enables alignment of an end of the exchange with a target synchronization boundary.
24. The apparatus of claim 23 , wherein the duration of the synchronization SIFS is between 13 microseconds and 19 microseconds.
25. The apparatus of claim 23 , further including means for determining the duration of the synchronization SIFS.
26. The apparatus of claim 25 , wherein the means for determining the duration of the synchronization SIFS is configured to determine an offset between the target synchronization boundary and a symbol granularity of the exchange.
27. The apparatus of claim 25 , wherein the frame from the wireless communication device is an acknowledgment after the synchronization SIFS that extends the exchange until the target synchronization boundary.
28. The apparatus of claim 27 , wherein the means for determining the duration of the synchronization SIFS is configured to subtract a duration of the acknowledgment from a time of the target synchronization boundary to determine an end of the synchronization SIF S.
29. The apparatus of claim 25 , wherein the exchange includes an acknowledgment from another device after the frame, and wherein the means for determining the duration of the synchronization SIFS is configured to subtract a duration of the frame, a predicted duration of the acknowledgment, and a predicted duration of a SIFS from a time of the target synchronization boundary to determine an end of the synchronization SIFS.
30. A non-transitory computer-readable medium including stored instructions for wireless communication by a wireless communication device, executable by a processor to:
acquire access to a wireless medium via a clear channel assessment (CCA) procedure; and
transmit, to another device, a frame within an exchange of frames during a transmission opportunity (TxOP) of the wireless communication device after a duration of a synchronization short inter-frame space (SIFS), wherein the duration of the synchronization SIFS enables alignment of an end of the exchange with a target synchronization boundary.