Frame formats and timing parameters in sub-1 GHz networks

Abstract

A method includes selecting a frame format for use in transmission of a packet via a wireless network. The transmission is associated with a particular bandwidth. The selected frame format is a first frame format if the particular bandwidth is equal to a threshold bandwidth. The selected frame format is the first frame format or a second frame format if the particular bandwidth is greater than the threshold bandwidth. The second frame format includes a first portion and a second portion. The first portion includes a short training field (STF), a long training field, and a signal A field, and the second portion includes a data portion including a second STF, one or more signal B fields, and a data field. The method further includes generating the packet in accordance with the selected frame format and one or more timing parameters and sending the packet.

What is claimed is:  
     
       1. A method comprising:
 selecting, at a transmitter, a frame format for use in transmission of a packet via a wireless network, the transmission associated with a particular bandwidth, wherein the selected frame format is a first frame format if the particular bandwidth is equal to a threshold bandwidth, wherein the selected frame format is the first frame format or a second frame format if the particular bandwidth is greater than the threshold bandwidth, wherein the second frame format comprises a first portion and a second portion, wherein the first portion comprises a short training field (STF), a long training field (LTF), and a signal A field (SIG-A), and wherein the second portion comprises a data portion including a second STF, one or more signal B fields (SIG-Bs), and a data field; 
 determining one or more timing parameters based on the selected frame format and the particular bandwidth; 
 generating the packet in accordance with the selected frame format and the one or more timing parameters; and 
 sending the packet from the transmitter to a receiver, 
 wherein the one or more timing parameters include:
 a number of complex data subcarriers, 
 a number of pilot subcarriers, 
 a number of total subcarriers excluding guards, 
 a highest data subcarrier index, 
 a subcarrier frequency spacing, 
 a discrete Fourier transform (DFT) period, 
 an inverse DFT (IDFT) period, 
 a guard interval duration, 
 a double guard interval duration, 
 a short guard interval duration, 
 an orthogonal frequency-division multiplexing (OFDM) symbol duration with long guard intervals, 
 an OFDM symbol duration with short guard intervals, 
 an OFDM symbol duration, 
 a number of bits in a SERVICE field, 
 a number of tail bits per binary convolution code encoder, 
 a short training field (STF) duration, 
 a long training field (LTF) duration, 
 a signal field (SIG) duration, 
 a signal A field (SIG-A) duration, 
 a multiple-input multiple-output LTF (MIMO-LTF) duration, 
 a long format STF duration, 
 a signal B field (SIG-B) duration, 
 or any combination thereof, and 
 
 wherein the STF duration, the LTF duration, and one of the SIG duration and the SIG-A duration are each longer if the particular bandwidth is equal to the threshold bandwidth than if the particular bandwidth is greater than the threshold bandwidth. 
 
     
     
       2. The method of  claim 1 , wherein the wireless network operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah protocol. 
     
     
       3. The method of  claim 1 , wherein the first frame format comprises a third STF, a second LTF, a signal field (SIG), and a second data field. 
     
     
       4. The method of  claim 3 , wherein if more than one spatial stream is associated with the transmission, the first frame format further comprises one or more additional LTFs. 
     
     
       5. The method of  claim 1 , wherein if more than one spatial stream is associated with the transmission, the second frame format further comprises one or more additional LTFs. 
     
     
       6. The method of  claim 1 , wherein the particular bandwidth is equal to 1 megahertz (MHz), 2 MHz, 4 MHz, 8 MHz, or 16 MHz. 
     
     
       7. The method of  claim 1 , wherein the threshold bandwidth is equal to 1 MHz. 
     
     
       8. The method of  claim 1 , further comprising scaling one or more fields of the first frame format or one or more fields of the second frame format based on the particular bandwidth, wherein the one or more fields of the second frame format include the STF, the LTF, the SIG-A, the second STF, the one or more SIG-Bs, and the data field, and wherein if the particular bandwidth is 2 megahertz (MHz):
 the STF is scaled by a factor of 12; 
 the LTF is scaled by a factor of 56; 
 the SIG-A is scaled by a factor of 52; 
 the second STF is scaled by a factor of 12; 
 the one or more SIG-Bs are scaled by a factor of 56; and 
 the data field is scaled by a factor of 56. 
 
     
     
       9. The method of  claim 8 , wherein if the particular bandwidth is 4 MHz:
 the STF is scaled by a factor of 24; 
 the LTF is scaled by a factor of 114; 
 the SIG-A is scaled by a factor of 104; 
 the second STF is scaled by a factor of 24; 
 the one or more SIG-Bs are scaled by a factor of 114; and 
 the data field is scaled by a factor of 114. 
 
     
     
       10. The method of  claim 1 , wherein:
 the subcarrier frequency spacing is 31.25 kilohertz (KHz); 
 the DFT period is 32 microseconds (μs); 
 the IDFT period is 32 μs; 
 the guard interval duration is 8 μs; 
 the double guard interval duration is 16 μs; 
 the short guard interval duration is 4 μs; 
 the OFDM symbol duration with long guard intervals is 40 μs; 
 the OFDM symbol duration with short guard intervals is 36 μs; 
 the OFDM symbol duration is 40 μs or 36 μs; 
 the number of bits in the SERVICE field is 16; 
 the number of tail bits per binary convolution code encoder is 6; and 
 the MIMO-LTF duration is 40 μs. 
 
     
     
       11. The method of  claim 1 , wherein if the particular bandwidth is 1 megahertz (MHz):
 the number of complex data subcarriers is 24; 
 the number of pilot subcarriers is 2; 
 the number of total subcarriers excluding guards is 26; 
 the highest data subcarrier index is 13; 
 the STF duration is 160 microseconds (μs); 
 the LTF duration is 160 μs; and 
 the SIG duration is 240 μs or 200 μs. 
 
     
     
       12. The method of  claim 1 , wherein if the particular bandwidth is greater than 1 megahertz (MHz):
 the STF duration is 80 microseconds (μs); 
 the LTF duration is 8 μs; 
 the SIG duration is 80 μs; 
 the SIG-A duration is 80 μs; 
 the long format STF duration is 40 μs; and 
 the SIG-B duration is 40 μs. 
 
     
     
       13. The method of  claim 1 , wherein if the particular bandwidth is 2 megahertz (MHz):
 the number of complex data subcarriers is 52; 
 the number of pilot subcarriers is 4; 
 the number of total subcarriers excluding guards is 56; and 
 the highest data subcarrier index is 28. 
 
     
     
       14. The method of  claim 1 , wherein if the particular bandwidth is 4 megahertz (MHz):
 the number of complex data subcarriers is 108; 
 the number of pilot subcarriers is 6; 
 the number of total subcarriers excluding guards is 114; and 
 the highest data subcarrier index is 58. 
 
     
     
       15. The method of  claim 1 , wherein if the particular bandwidth is 8 megahertz (MHz):
 the number of complex data subcarriers is 234; 
 the number of pilot subcarriers is 8; 
 the number of total subcarriers excluding guards is 242; and 
 the highest data subcarrier index is 122. 
 
     
     
       16. The method of  claim 1 , wherein if the particular bandwidth is 16 megahertz (MHz):
 the number of complex data subcarriers is 468; 
 the number of pilot subcarriers is 16; 
 the number of total subcarriers excluding guards is 484; and 
 the highest data subcarrier index is 250. 
 
     
     
       17. A non-transitory processor-readable medium storing:
 one or more data structures, the one or more data structures indicating timing parameters for a first frame format and a second frame format of a wireless network, wherein a particular bandwidth is associated with the first frame format if the particular bandwidth is equal to a threshold bandwidth, wherein the particular bandwidth is associated with the first frame format or the second frame format if the particular bandwidth is greater than the threshold bandwidth, wherein the second frame format comprises a first portion and a second portion, wherein the first portion comprises a short training field (STF), a long training field (LTF), and a signal A field (SIG-A), and wherein the second portion comprises a data portion including a second STF, one or more signal B fields (SIG-Bs), and a data field; 
 wherein the timing parameters include:
 a number of complex data subcarriers; 
 a number of pilot subcarriers; 
 a number of total subcarriers excluding guards; 
 a highest data subcarrier index; 
 a subcarrier frequency spacing; 
 an inverse discrete Fourier transform (IDFT) period; 
 a discrete Fourier transform (DFT) period; 
 a guard interval duration; 
 a double guard interval duration; 
 a short guard interval duration; 
 an orthogonal frequency-division multiplexing (OFDM) symbol duration with long guard intervals; 
 an OFDM symbol duration with short guard intervals; 
 an OFDM symbol duration; 
 a number of bits in a SERVICE field; 
 a number of tail bits per binary convolution code encoder; 
 a short training field (STF) duration; 
 a long training field (LTF) duration; 
 a signal field (SIG) duration; 
 a signal A field (SIG-A) duration; 
 a multiple-input multiple-output LTF (MIMO-LTF) duration; 
 a long format STF duration; 
 a signal B field (SIG-B) duration; 
 or any combination thereof, and 
 
 wherein:
 the subcarrier frequency spacing is 31.25 kilohertz (KHz); 
 the DFT period is 32 microseconds (μs); 
 the IDFT period is 32 μs; 
 the guard interval duration is 8 μs; 
 the double guard interval duration is 16 μs; 
 the short guard interval duration is 4 μs; 
 the OFDM symbol duration with long guard intervals is 40 μs; 
 the OFDM symbol duration with short guard intervals is 36 μs; 
 the OFDM symbol duration is 40 μs or 36 μs; 
 the number of bits in the SERVICE field is 16; 
 the number of tail bits per binary convolution code encoder is 6; and 
 the MIMO-LTF duration is 40 μs. 
 
 
     
     
       18. The non-transitory processor-readable medium of  claim 17 , wherein the one or more data structures further indicate tone scaling parameters associated with the first frame format and the second frame format. 
     
     
       19. The non-transitory processor-readable medium of  claim 17 , wherein the first frame format comprises a third STF, a second LTF, a signal field (SIG), and a second data field. 
     
     
       20. The non-transitory processor-readable medium of  claim 19 , wherein the SIG field is scaled by a tone scaling parameter that is based on the particular bandwidth. 
     
     
       21. An apparatus comprising:
 a memory storing one or more data structures associated with a wireless network; and 
 a processor coupled to the memory, the processor configured to:
 select a frame format for use in transmission of a packet via the wireless network, the transmission associated with a particular bandwidth, wherein the selected frame format is a first frame format if the particular bandwidth is equal to a threshold bandwidth, wherein the selected frame format is the first frame format or a second frame format if the particular bandwidth is greater than the threshold bandwidth, wherein the second frame format comprises a first portion and a second portion, wherein the first portion comprises a short training field (STF), a long training field (LTF), and a signal A field (SIG-A), and wherein the second portion comprises a data portion including a second STF, one or more signal B fields (SIG-Bs), and a data field; 
 determine one or more timing parameters based on the selected frame format and the particular bandwidth; and 
 generate the packet in accordance with the selected frame format and the one or more timing parameters, 
 
 wherein the one or more timing parameters include:
 a number of complex data subcarriers; 
 a number of pilot subcarriers; 
 a number of total subcarriers excluding guards; 
 a highest data subcarrier index; 
 a subcarrier frequency spacing; 
 a discrete Fourier transform (DFT) period; 
 an inverse DFT (IDFT) period; 
 a guard interval duration; 
 a double guard interval duration; 
 a short guard interval duration; 
 an orthogonal frequency-division multiplexing (OFDM) symbol duration with long guard intervals; 
 an OFDM symbol duration with short guard intervals; 
 an OFDM symbol duration; 
 a number of bits in a SERVICE field; 
 a number of tail bits per binary convolution code encoder; 
 a short training field (STF) duration; 
 a long training field (LTF) duration; 
 a signal field (SIG) duration; 
 a signal A field (SIG-A) duration; 
 a multiple-input multiple-output LTF (MIMO-LTF) duration; 
 a long format STF duration; 
 a signal B field (SIG-B) duration; 
 or any combination thereof, and 
 
 wherein if the particular bandwidth is 1 megahertz (MHz):
 the number of complex data subcarriers is 24; 
 the number of pilot subcarriers is 2; 
 the number of total subcarriers excluding guards is 26; 
 the highest data subcarrier index is 13; 
 the STF duration is 160 microseconds (μs); 
 the LTF duration is 160 μs; and 
 the SIG duration is 240 μs or 200 μs. 
 
 
     
     
       22. The apparatus of  claim 21 , wherein the wireless network operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah protocol. 
     
     
       23. An apparatus comprising:
 means for storing one or more data structures associated with a wireless network; 
 means for selecting a frame format for use in transmission of a packet via the wireless network, the transmission associated with a particular bandwidth, wherein the selected frame format is a first frame format if the particular bandwidth is equal to a threshold bandwidth, wherein the selected frame format is the first frame format or a second frame format if the particular bandwidth is greater than the threshold bandwidth, wherein the second frame format comprises a first portion and a second portion, wherein the first portion comprises a short training field (STF), a long training field (LTF), and a signal A field (SIG-A), and wherein the second portion comprises a data portion including a second STF, one or more signal B fields (SIG-Bs), and a data field; 
 means for determining one or more timing parameters based on the selected frame format and the particular bandwidth; 
 means for generating the packet in accordance with the selected frame format and the one or more timing parameters; and 
 means for scaling one or more fields of the first frame format or one or more fields of the second frame format based on the particular bandwidth, wherein the one or more fields of the second frame format include the STF, the LTF, the SIG-A, the second STF, the one or more SIG-Bs, and the data field, 
 wherein if the particular bandwidth is 2 megahertz (MHz):
 the STF is scaled by a factor of 12; 
 the LTF is scaled by a factor of 56; 
 the SIG-A is scaled by a factor of 52; 
 the second STF is scaled by a factor of 12; 
 the one or more SIG-Bs are scaled by a factor of 56; and 
 the data field is scaled by a factor of 56. 
 
 
     
     
       24. The apparatus of  claim 23 , further comprising means for selecting tone scaling parameters based on selection of the first frame format or the second frame format. 
     
     
       25. The apparatus of  claim 23 , wherein the one or more timing parameters include a short training field (STF) duration, a long training field (LTF) duration, a signal field (SIG) duration, and a signal A field (SIG-A) duration, and wherein the STF duration, the LTF duration, and one of the SIG duration and the SIG-A duration are each longer if the particular bandwidth is equal to the threshold bandwidth than if the particular bandwidth is greater than the threshold bandwidth. 
     
     
       26. The apparatus of  claim 23 , wherein the one or more timing parameters include a number of complex data subcarriers, a number of pilot subcarriers, a number of total subcarriers excluding guards, and a highest data subcarrier index, and wherein if the particular bandwidth is 16 megahertz (MHz):
 the number of complex data subcarriers is 468; 
 the number of pilot subcarriers is 16; 
 the number of total subcarriers excluding guards is 484; and 
 the highest data subcarrier index is 250. 
 
     
     
       27. The apparatus of  claim 23 , wherein if the particular bandwidth is 4 MHz:
 the STF is scaled by a factor of 24; 
 the LTF is scaled by a factor of 114; 
 the SIG-A is scaled by a factor of 104; 
 the second STF is scaled by a factor of 24; 
 the one or more SIG-Bs are scaled by a factor of 114; and 
 the data field is scaled by a factor of 114. 
 
     
     
       28. The apparatus of  claim 23 , wherein if the particular bandwidth is 8 MHz:
 the STF is scaled by a factor of 48; 
 the LTF is scaled by a factor of 242; 
 the SIG-A is scaled by a factor of 208; 
 the second STF is scaled by a factor of 48; 
 the one or more SIG-Bs are scaled by a factor of 242; and 
 the data field is scaled by a factor of 242. 
 
     
     
       29. The apparatus of  claim 23 , wherein if the particular bandwidth is 16 MHz:
 the STF is scaled by a factor of 96; 
 the LTF is scaled by a factor of 484; 
 the SIG-A is scaled by a factor of 416; 
 the second STF is scaled by a factor of 96; 
 the one or more SIG-Bs are scaled by a factor of 484; and 
 the data field is scaled by a factor of 484. 
 
     
     
       30. The apparatus of  claim 23 , wherein the SIG-A is scaled by a tone scaling parameter that is based on the particular bandwidth.