Dual interpretation of a length field of a signal unit
A method includes receiving, at a first wireless device from a second wireless device, a signal (SIG) unit including a length field and an aggregation field. The length field is interpreted as a number of symbols in response to determining that the aggregation field has a first value. The length field is interpreted as a number of bytes in response to determining that the aggregation field has a second value.
1. A method comprising:
receiving, at a first wireless device from a second wireless device, a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
interpreting a 9-bit length field of the SIG unit,
wherein the 9-bit length field is interpreted as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value,
wherein the 9-bit length field is interpreted as a number of bytes in response to determining that the 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a short format preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit first reserved field;
a 1-bit space-time block code (STBC) field;
a 1-bit second reserved field;
a 2-bit bandwidth field;
a 2-bit number of space time streams field;
a 9-bit partial association identifier field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 4-bit modulation and coding scheme (MCS) field;
a 1-bit smoothing field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
2. The method of claim 1 , wherein the sub-1 GHz wireless network operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah protocol.
3. The method of claim 2 , wherein the 1-bit STBC field and the 1-bit SGI field precede the 1-bit smoothing field.
4. The method of claim 1 , wherein the 1-bit aggregation field indicates whether the second wireless device is transmitting aggregated media access control (MAC) protocol data units (A-MPDUs) to the first wireless device.
5. The method of claim 1 , wherein the SIG unit comprises two orthogonal frequency-division multiplexing (OFDM) symbols, wherein the SIG unit is encoded at a rate of one-half, and wherein the SIG unit corresponds to a binary phase-shift keying (BPSK) constellation.
6. The method of claim 1 , wherein the SIG unit is included in a preamble of a packet.
7. An apparatus comprising:
a receiver configured to receive a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
a processor configured to:
interpret a 9-bit length field of the SIG unit as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value; and
interpret the 9-bit length field as a number of bytes in response to determining that the 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a short format preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit first reserved field;
a 1-bit space-time block code (STBC) field;
a 1-bit second reserved field;
a 2-bit bandwidth field;
a 2-bit number of space time streams field;
a 9-bit partial association identifier field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 4-bit modulation and coding scheme (MCS) field;
a 1-bit smoothing field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
8. The apparatus of claim 7 , wherein the 1-bit aggregation field indicates whether data received by the receiver corresponds to one or more aggregated media access control (MAC) protocol data units (A-MPDUs).
9. An apparatus comprising:
means for receiving a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
means for processing for interpreting a 9-bit length field of the SIG unit,
wherein the means for processing interprets the 9-bit length field as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value,
wherein the means for processing interprets the 9-bit length field as a number of bytes in response to determining that the 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a short format preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit first reserved field;
a 1-bit space-time block code (STBC) field;
a 1-bit second reserved field;
a 2-bit bandwidth field;
a 2-bit number of space time streams field;
a 9-bit partial association identifier field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 4-bit modulation and coding scheme (MCS) field;
a 1-bit smoothing field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
10. A non-transitory computer-readable medium comprising instructions that, when executed by a computer, cause the computer to:
receive a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
interpret a 9-bit length field of the SIG unit,
wherein the 9-bit length field is interpreted as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value,
wherein the 9-bit length field is interpreted as a number of bytes in response to determining that 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a short format preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit first reserved field;
a 1-bit space-time block code (STBC) field;
a 1-bit second reserved field;
a 2-bit bandwidth field;
a 2-bit number of space time streams field;
a 9-bit partial association identifier field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 4-bit modulation and coding scheme (MCS) field;
a 1-bit smoothing field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
11. A method comprising:
receiving, at a first wireless device from a second wireless device, a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
interpreting a 9-bit length field of the SIG unit,
wherein the 9-bit length field is interpreted as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value,
wherein the 9-bit length field is interpreted as a number of bytes in response to determining that the 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a long format single user (SU) preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit multi user (MU)/SU field;
a 1-bit space-time block code (STBC) field;
a 1-bit reserved field;
a 2-bit bandwidth field;
a 2-bit number of space time streams field;
a 9-bit partial association identifier field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 4-bit modulation and coding scheme (MCS) field;
a 1-bit beam-change indication field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
12. The method of claim 11 , wherein the SIG unit comprises two orthogonal frequency-division multiplexing (OFDM) symbols, wherein the SIG unit is encoded at a rate of one-half, and wherein the SIG unit corresponds to a binary phase-shift keying (BPSK) constellation.
13. A method comprising:
receiving, at a first wireless device from a second wireless device, a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
interpreting a 9-bit length field of the SIG unit as a number of symbols,
wherein the SIG unit corresponds to a long format multi user (MU) preamble and a bandwidth greater than or equal to 2 megahertz (MHz), and
wherein the SIG unit comprises:
a 1-bit MU/single user (SU) field;
a 1-bit space-time block code (STBC) field;
a 1-bit first reserved field;
an 8-bit number of space time streams field, wherein the number of space time streams field includes four 2-bit values corresponding to four users;
a 2-bit bandwidth field;
a 6-bit group identifier (GID) field;
a 1-bit short guard interval (SGI) field;
a 4-bit first coding field;
a 1-bit second coding field;
a 1-bit second reserved field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
14. The method of claim 13 , wherein the SIG unit comprises two orthogonal frequency-division multiplexing (OFDM) symbols, wherein the SIG unit is encoded at a rate of one-half, and wherein the SIG unit corresponds to a binary phase-shift keying (BPSK) constellation.
15. A method comprising:
receiving, at a first wireless device from a second wireless device, a signal (SIG) unit via a sub-1 gigahertz (GHz) wireless network; and
interpreting a 9-bit length field of the SIG unit,
wherein the 9-bit length field is interpreted as a number of symbols in response to determining that a 1-bit aggregation field of the SIG unit has a first value,
wherein the 9-bit length field is interpreted as a number of bytes in response to determining that the 1-bit aggregation field has a second value,
wherein the SIG unit corresponds to a 1 megahertz (MHz) bandwidth-rftede, and
wherein the SIG unit comprises:
a 2-bit number of space time streams field;
a 1-bit short guard interval (SGI) field;
a 2-bit coding field;
a 1-bit space-time block code (STBC) field;
a 1-bit first reserved field;
a 4-bit modulation and coding scheme (MCS) field;
the 1-bit aggregation field;
the 9-bit length field;
a 2-bit acknowledgement (ACK) indication field;
a 4-bit cyclic redundancy check (CRC) field; and
a 6-bit tail field.
16. The method of claim 15 , wherein the SIG unit comprises six orthogonal frequency-division multiplexing (OFDM) symbols, wherein the SIG unit is encoded at a rate of one-half, and wherein the SIG unit corresponds to a binary phase-shift keying (BPSK) constellation.