Physical layer protocol data unit transmission method and apparatus
Methods, apparatus, and systems for a physical layer protocol data unit (PPDU) transmission are provided. In one aspect, a method includes: generating a physical layer protocol data unit (PPDU) including a signal extension (SE) field arranged after a last orthogonal frequency division multiplexing (OFDM) symbol of a plurality of OFDM symbols, the PPDU including indication information in a high efficiency signaling field (HE-SIG), the indication information being generated based on a symbol length of the SE field and configured to indicate whether a receive end needs to adjust a calculated quantity of the plurality of OFDM symbols, and sending the PPDU to the receive end.
1. A physical layer protocol data unit transmission method, the method comprising:
generating, by a transmit end, a physical layer protocol data unit (PPDU), wherein the PPDU comprises a signal extension (SE) field arranged after a last orthogonal frequency division multiplexing (OFDM) symbol of a plurality of OFDM symbols in the PPDU, wherein the PPDU comprises an ambiguity indication in a high efficiency signaling (HE-SIG) field, the ambiguity indication indicates whether a receive end needs to adjust a calculated quantity of the plurality of OFDM symbols;
when T SE +Δ RE >(12.8+T GI ) is satisfied, the ambiguity indication is a first value, and
when T SE +Δ RE <(12.8+T GI ) is satisfied, the ambiguity indication is a second value different from the first value,
where T SE represents a transmission duration of the SE field,
Δ RE represents a difference between an actual transmission duration and an indicated transmission duration, and
T GI represents a transmission duration of a cyclic prefix, wherein (12.8+T GI ) represents a transmission duration of a 4× OFDM symbol;
sending, by the transmit end, the PPDU to the receive end.
2. The method according to claim 1 , wherein the indicated transmission duration is indicated by L-Length in a preamble of the PPDU.
3. The method according to claim 2 , wherein a value of the L-Length is:
L_LENGTH
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
-
20
4
⌉
×
3
-
3
+
m
,
m
=
1
or
2
;
or
L_LENGTH
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
3
-
3
+
m
,
m
=
1
or
2
where m is a remainder of L-LENGTH modulo 3, T HE_DATA =N·(12.8+T GI ) N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
4. The method according to claim 1 , wherein the ambiguity indication comprises one bit, the first value of the ambiguity indication is 1.
5. The method according to claim 1 , wherein Δ RE =TXTIME*-TXTIME; and TXTIME* is the indicated transmission duration indicated by L-Length in a preamble of the PPDU, TXTIME is the actual transmission duration associated with the PPDU.
6. The method according to claim 5 , wherein
TXTIME
=
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
,
and
TXTIME
*
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
;
Δ
RE
=
TXTIME
*
-
TXTIME
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
4
⌉
×
4
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
;
where T HE_DATA =N·(12.8+T GI ), N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
7. The method according to claim 5 , wherein
TXTIME
=
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
,
and
TXTIME
*
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
;
Δ
RE
=
TXTIME
*
-
TXTIME
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
4
⌉
×
4
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
;
where T HE_DATA =N·(12.8+T GI ), N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
8. A physical layer protocol data unit receiving method, comprising:
receiving, by a receive end, a physical layer protocol data unit (PPDU), wherein the PPDU comprises a signal extension (SE) field arranged after a last orthogonal frequency division multiplexing (OFDM) symbol of a plurality of OFDM symbols in the PPDU, wherein the PPDU comprises an ambiguity indication in a high efficiency signaling (HE-SIG) field, the ambiguity indication indicates whether the receive end needs to adjust a calculated quantity of the plurality of OFDM symbols;
parsing the PPDU to determine a quantity M of the plurality of OFDM symbols carried in the PPDU; and
determining whether to adjust the determined quantity M based on the ambiguity indication of the PPDU,
wherein
when a value of the ambiguity indication is a first value, T SE +Δ RE >(12.8+T GI ) is satisfied, and
when a value of the ambiguity indication is a second value, T SE +Δ RE <(12.8+T GI ) is satisfied, the second value being different from the first value,
where T SE represents a transmission duration of the SE field; Δ RE represents a difference between an actual transmission duration and an indicated transmission duration, and
T GI represents a transmission duration of a cyclic prefix, wherein (12.8+T GI ) represents a transmission duration of a 4× OFDM symbol.
9. The method according to claim 8 ,
wherein determining whether to adjust the determined quantity M based on the ambiguity indication of the PPDU comprises:
keeping a value of the determined quantity M unchanged when the value of the ambiguity indication is the first value; and
subtracting 1 from the determined quantity M when the value of the ambiguity indication is the second value.
10. The method according to claim 8 , wherein the ambiguity indication comprises one bit, the first value of the ambiguity indication is 1.
11. A physical layer protocol data unit transmission apparatus, the apparatus comprising:
at least one processor; and
a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the apparatus to:
generate a physical layer protocol data unit (PPDU), wherein the PPDU comprises a signal extension (SE) field arranged after a last orthogonal frequency division multiplexing (OFDM) symbol of a plurality of OFDM symbols, wherein the PPDU comprises an ambiguity indication in a high efficiency signaling (HE-SIG) field, the ambiguity indication indicates whether a receive end needs to adjust a calculated quantity of the plurality of OFDM symbols; and
send the PPDU to the receive end;
when T SE +Δ RE >(12.8+T GI ) is satisfied, the ambiguity indication is a first value; and
when T SE +Δ RE <(12.8+T GI )is satisfied, the ambiguity indication is a second value different from the first value,
where T SE represents a transmission duration of the SE field,
Δ RE represents a difference between an actual transmission duration and an indicated transmission duration, and
T GI represents a transmission duration of a cyclic prefix, wherein (12.8+T GI ) represents a transmission duration of a 4× OFDM symbol.
12. The apparatus according to claim 11 , configured to be an access point in a wireless local area network,
wherein the access point comprises a network interface coupled to the at least one processor.
13. The apparatus according to claim 11 , wherein the indicated transmission duration is indicated by L-Length in a preamble of the PPDU.
14. The apparatus according to claim 13 , wherein a value of the L-Length is:
L_LENGTH
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
-
20
4
⌉
×
3
-
3
+
m
,
m
=
1
or
2
;
or
L_LENGTH
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
3
-
3
+
m
,
m
=
1
or
2
where m is a remainder of L-LENGTH modulo 3, T HE_DATA =N·(12.8+T GI ) N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
15. The apparatus according to claim 11 , wherein the ambiguity indication comprises one bit, the first value of the ambiguity indication is 1.
16. The apparatus according to claim 11 , wherein Δ RE =TXTIME*-TXTIME; and TXTIME* is the indicated transmission duration indicated by L-Length included in a preamble of the PPDU, TXTIME is the actual transmission duration associated with the PPDU.
17. The apparatus according to claim 16 , wherein
TXTIME
=
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
,
and
TXTIME
*
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
;
Δ
RE
=
TXTIME
*
-
TXTIME
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
4
⌉
×
4
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
;
where T HE_DATA =N·(12.8+T GI ), N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
18. The apparatus according to claim 16 , wherein
TXTIME=T L_PREAMBLE +T HE_PREAMBLE +T HE_DATA ,
TXTIME
=
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
,
and
TXTIME
*
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
;
Δ
RE
=
TXTIME
*
-
TXTIME
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
-
20
4
⌉
×
4
+
20
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
=
⌈
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
4
⌉
×
4
-
(
T
L
_
PREAMBLE
+
T
HE
_
PREAMBLE
+
T
HE
_
DATA
+
T
SE
)
;
where T HE_DATA =N·(12.8+T GI ), N being a quantity of 4× OFDM symbols that actually need to be transmitted, T L_PREAMBLE represents a transmission duration of a L-preamble of the PPDU, and T HE_PREAMBLE represents a transmission duration of a HE-preamble of the PPDU.
19. A physical layer protocol data unit receiving apparatus, comprising:
at least one processor; and
a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the apparatus to:
receive a physical layer protocol data unit (PPDU), wherein the PPDU comprises a signal extension (SE) field arranged after a last orthogonal frequency division multiplexing (OFDM) symbol of a plurality of OFDM symbols, wherein the PPDU comprises an ambiguity indication in a high efficiency signaling (HE-SIG) field, the ambiguity indication indicates whether a receive end needs to adjust a calculated quantity of the plurality of OFDM symbols;
parse the PPDU to determine a quantity M of the plurality of OFDM symbols carried in the PPDU; and
determine whether to adjust the determined quantity M based on the ambiguity indication of the PPDU,
wherein
when a value of the ambiguity indication is a first value, T SE +Δ RE >(12.8+T GI ) is satisfied, and
when a value of the ambiguity indication is a second value, T SE +Δ RE <(12.8+T GI ) is satisfied, the second value being different from the first value,
where T SE represents a duration of the SE field,
Δ RE represents a difference between an actual transmission duration and an indicated transmission duration, and
T GI represents a transmission duration of a cyclic prefix, wherein (12.8+T GI ) represents a transmission duration of a 4× OFDM symbol.
20. The apparatus according to claim 19 , wherein the programming instructions instruct the at least one processor to:
keep a value of the determined quantity M unchanged when the ambiguity indication is the first value, and
subtract 1 from the determined quantity M when the ambiguity indication is the second value.
21. The apparatus according to claim 19 , configured to be a station in a wireless local area network,
wherein the station comprises a network interface coupled to the at least one processor.
22. The apparatus according to claim 19 , wherein the ambiguity indication comprises one bit, the first value of the ambiguity indication is 1.