Physical layer protocol data unit transmission method and apparatus
Embodiments of the present disclosure provide a physical layer protocol data unit PPDU transmission method and a corresponding PPDU transmission apparatus. Application of the method and apparatus in the embodiments of the present disclosure enables a receive end to quickly determine the starting position of the feature signal sequence by means of blind detection, and ensures that the receive end quickly completes data processing and status switching.
1. A method for transmitting a physical layer protocol data unit (PPDU), applied in a wireless local area network and comprising:
generating, by a transmit end, a PPDU, wherein the PPDU comprises indication information, the indication information is located in a high efficiency signaling (HE-SIG) field, the PPDU comprises a signal extension (SE) field, and the SE field is located behind a last orthogonal frequency division multiplexing (OFDM) symbol that carries useful information; and
the indication information indicates whether a receive end needs to subtract 1 from a quantity M1 of OFDM symbols calculated by the receive end; wherein a first value of the indication information indicates to the receive end to keep a value of M1 unchanged, and a second value of the indication information indicates to the receive end to subtract 1 from the value of M1;
sending the PPDU to the receive end.
2. The method according to claim 1 , wherein the method further comprising
setting a value of the indication information based on a quantity of OFDM symbols actually included in the PPDU and a length of the SE field.
3. A method for receiving a physical layer protocol data unit (PPDU), applied in a wireless local area network and comprising:
receiving, by a receive end, a PPDU from a transmit end, wherein the PPDU comprises indication information, the indication information is located in a high efficiency signaling (HE-SIG) field, the PPDU comprises a signal extension (SE) field, and the SE field is located behind a last orthogonal frequency division multiplexing (OFDM) symbol that carries useful information; and
the indication information indicates whether the receive end needs to subtract 1 from a quantity M1 of OFDM symbols calculated by the receive end; wherein a first value of the indication information indicates to the receive end to keep a value of M1 unchanged, and a second value of the indication information indicates to the receive end to subtract 1 from the value of M1;
parsing, by the receive end, the PPDU to obtain the quantity M1 of OFDM symbols in the PPDU.
4. The method according to claim 3 , wherein the parsing the PPDU comprises:
keeping the value of M1 unchanged if a value of the indication information is the first value; and
subtracting 1 from the value of M1 if a value of the indication information is the second value.
5. The method according to claim 3 , wherein the value of M1 represents the quantity of OFDM symbols for the receive end and M1 is calculated by the receive end using a length field in a legacy signaling (L-SIG) field in the PPDU.
6. The method according to claim 5 , wherein
M
1
=
⌊
RXTIME
-
T
L
_
PREAMBLE
-
T
HE
_
PREAMBLE
T
GI
+
12.8
⌋
RXTIME
=
⌈
L
_
LENGTH
-
m
+
3
3
⌉
×
4
+
20
,
m
=
1
or
2
;
L_LENGTH represents a length indication in a L-preamble of the transmit end;
T L_PREAMBLE represents a transmission time of the L-preamble; and
T HE_PREAMBLE represents a transmission time of a HE-preamble.
7. A physical layer protocol data unit (PPDU) transmission apparatus, applied in a wireless local area network and comprising:
a transceiver, configured to receive a PPDU from a transmit end, wherein the PPDU comprises indication information, the indication information is located in a high efficiency signaling (HE-SIG) field, the PPDU comprises a signal extension (SE) field, and the SE field is located after a last orthogonal frequency division multiplexing (OFDM) symbol that carries useful information; and
the indication information indicates whether the transmission apparatus needs to subtract 1 from a quantity M1 of OFDM symbols calculated by the transmission apparatus; wherein a first value of the indication information indicates to the transmission apparatus to keep a value of M1 unchanged, and a second value of the indication information indicates to the receive end to subtract 1 from the value of M1;
a processor, configured to parse the PPDU to obtain the quantity M1 of OFDM symbols in the PPDU.
8. The transmission apparatus according to claim 7 , wherein the processor configured to parse the PPDU comprises:
keeping the value of M1 unchanged if a value of the indication information is the first value; and
subtracting 1 from the value of M1 if a value of the indication information is the second value.
9. The transmission apparatus according to claim 7 , wherein the value of M1 represents the quantity of OFDM symbols for the transmission apparatus and M1 is calculated by the transmission apparatus using a length field in a legacy signaling (L-SIG) field in the PPDU.
10. The transmission apparatus according to claim 9 , wherein
M
1
=
⌊
RXTIME
-
T
L
_
PREAMBLE
-
T
HE
_
PREAMBLE
T
GI
+
12.8
⌋
RXTIME
=
⌈
L
_
LENGTH
-
m
+
3
3
⌉
×
4
+
20
,
m
=
1
or
2
;
L_LENGTH represents a length indication in a L-preamble of the transmit end;
T L_PREAMBLE represents a transmission time of the L-preamble; and
T HE_PREAMBLE represents a transmission time of a HE-preamble.
11. A physical layer protocol data unit (PPDU) transmission apparatus, applied in a wireless local area network and comprising:
a processor, configured to generate a PPDU, wherein the PPDU comprises indication information, the indication information is located in a high efficiency signaling (HE-SIG) field, the PPDU comprises a signal extension (SE) field, and the SE field is located after a last orthogonal frequency division multiplexing (OFDM) symbol that carries useful information; and
the indication information indicates whether a receive end needs to subtract 1 from a quantity M1 of OFDM symbols calculated by the receive end; wherein a first value of the indication information indicates to the receive end to keep a value of M1 unchanged, and a second value of the indication information indicates to the receive end to subtract 1 from the value of M1;
a transceiver, configured to send a PPDU.
12. The transmission apparatus according to claim 11 , wherein the processor is further configured to set a value of the indication information based on a quantity of OFDM symbols actually included in the PPDU and a length of the SE field.