Modulation and coding schemes in sub-1 GHz networks

• US 9,100,947 B2
• Filed: 03/01/2013
• Issued: 08/04/2015
• Est. Priority Date: 04/02/2012
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Baik, Eugene J, Vermani, Sameer
• Primary Examiner(s): Thompson, Jr., Otis L
• Application Number:
  US13/782,340
• Publication Number:
  US 20130258955A1
• Time in Patent Office: 886 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0016 involving special memory structures, e.g. look-up tables
• CPC Class Codes: H04W 72/04 Wireless resource allocation

Abstract

Systems and methods of controlling characteristics of messages in sub-1 GHz networks (e.g., IEEE 802.11ah networks) are disclosed. One or more data structures indicating available modulation and coding schemes (MCSs) may be stored at or accessible to transmitters and receivers. The data structures may be organized based on an MCS index, a frame format, a wireless network bandwidth, and/or the number of spatial streams in use at the wireless network. Information stored in the data structures may be used in generation and processing of messages communicated via the sub-1 GHz network.

Claims

1. A non-transitory processor-readable medium storing:

one or more data structures for use during communication via a sub-one gigahertz wireless network, the one or more data structures corresponding to one or more available bandwidths of the sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network,

wherein the one or more available bandwidths of the sub-one gigahertz wireless network include a bandwidth of one megahertz, and

wherein each data structure indicates, for each of a plurality of modulation and coding scheme (MCS) indexes;

a modulation scheme of a packet that includes the MCS index;

a coding rate to encode the packet;

a number of bits per subcarrier symbol in the packet;

a number of data symbols in the packet; and

a number of pilot symbols in the packet;

a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol in the packet;

a number of data bits per OFDM symbol in the packet, and

wherein at least one of the one or more data structures indicates, for the bandwidth of the one megahertz and when one spatial stream is in use;

when the MCS index is 10, the modulation scheme is binary phase-shift keying (BPSK), the number of bits per subcarrier symbol is 1, the number of coded bits per OFDM symbol is 26, and the number of data bits per OFDM symbol is 6.

2. The non-transitory processor-readable medium of claim 1, wherein each data structure further indicates, for each of the plurality of MCS indexes:

a number of encoders; and

at least one data rate associated with the packet, wherein all of the data structures indicate, for each of the plurality of MCS indexes, that a single encoder is to encode the packet.

3. The non-transitory processor-readable medium of claim 2, wherein the at least one data rate includes a first data rate associated with first guard intervals in the packet and a second data rate associated with second guard intervals in the packet.

4. The non-transitory processor-readable medium of claim 3, wherein the first guard intervals each have a duration of eight microseconds and the second guard intervals each have a duration of four microseconds.

5. The non-transitory processor-readable medium of claim 1, wherein the number of data symbols is 24.

6. The non-transitory processor-readable medium of claim 2, wherein the at least one of the one or more data structures indicates that:

when an operating bandwidth of the sub-one gigahertz wireless network is 2 megahertz and when 1, 2, or 4 spatial streams are in use, the MCS index equal to 9 is unavailable;

when the operating bandwidth is 8 megahertz and 3 spatial streams are in use, wherein when the MCS index is 6, the modulation scheme is 64-QAM, the coding rate is ¾

, and the number of bits per subcarrier symbol is 6; and

when the operating bandwidth is 16 megahertz and three spatial streams are in use, wherein when the MCS index is 9, the modulation scheme is 256-QAM, the coding rate is ⅚

, and the number of bits per subcarrier symbol is 8.

7. The non-transitory processor-readable medium of claim 2, wherein the particular MCS index is unavailable based on the number of data bits per OFDM symbol being a non-integer, a quotient of the number of data bits per OFDM symbol and the number of encoders being a non-integer, or a quotient of the number of coded bits per OFDM symbol and the number of encoders being a non-integer.

8. The non-transitory processor-readable medium of claim 1, wherein at least one of the data structures indicates, for at least one bandwidth and at least one number of spatial streams:

when the MCS index is 0, the modulation scheme is BPSK, the coding rate is ½

, and the number of bits per subcarrier symbol is 1;

when the MCS index is 1, the modulation scheme is quadrature phase-shift keying (QPSK), the coding rate is ½

, and the number of bits per subcarrier symbol is 2;

when the MCS index is 2, the modulation scheme is QPSK, the coding rate is ¾

, and the number of bits per subcarrier symbol is 2;

when the MCS index is 3, the modulation scheme is 16-point quadrature amplitude modulation (16-QAM), the coding rate is ½

, and the number of bits per subcarrier symbol is 4;

when the MCS index is 4, the modulation scheme is 16-QAM, the coding rate is ¾

, and the number of bits per subcarrier symbol is 4;

when the MCS index is 5, the modulation scheme is 64-point QAM (64-QAM), the coding rate is ⅔

, and the number of bits per subcarrier symbol is 6;

when the MCS index is 6, the modulation scheme is 64-QAM, the coding rate is ¾

, and the number of bits per subcarrier symbol is 6;

when the MCS index is 7, the modulation scheme is 64-QAM, the coding rate is ⅚

, and the number of bits per subcarrier symbol is 6;

when the MCS index is 8, the modulation scheme is 256-point QAM (256-QAM), the coding rate is ¾

, and the number of bits per subcarrier symbol is 8;

when the MCS index is 9, the modulation scheme is 256-QAM, the coding rate is ⅚

, and the number of bits per subcarrier symbol is 8;

or

any combination thereof.

9. The non-transitory processor-readable medium of claim 2, wherein at least one of the data structures indicates:

when an operating bandwidth of the sub-one gigahertz wireless network is 1 megahertz;

the number of data symbols is 24;

the number of pilot symbols is 2; and

the number of encoders is 1;

when the operating bandwidth is 2 megahertz;

the number of data symbols is 52;

the number of pilot symbols is 4; and

the number of encoders is 1;

when the operating bandwidth is 4 megahertz;

the number of data symbols is 108;

the number of pilot symbols is 6; and

the number of encoders is 1 or 2;

when the operating bandwidth is 8 megahertz;

the number of data symbols is 234;

the number of pilot symbols is 8; and

the number of encoders is 1, 2, or 3; and

when the operating bandwidth is 16 megahertz;

the number of data symbols is 468;

the number of pilot symbols is 16; and

the number of encoders is 1, 2, 3, 4, or 6.

10. The non-transitory processor-readable medium of claim 1, wherein at least one of the one or more data structures indicates that a particular MCS is unavailable.

11. The non-transitory processor-readable medium of claim 1, wherein the sub-one gigahertz wireless network operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah protocol.

12. The non-transitory processor-readable medium of claim 1, further comprising instructions that, when executed by a processor, cause the processor to:

receive a first packet via the sub-one gigahertz wireless network operating at a first bandwidth while using a first number of spatial streams;

extract a first MCS index from the first packet;

identify a first data structure of the one or more data structures that corresponds to the first bandwidth and the first number of spatial streams,

determine, based on the first MCS index and the first data structure, at least one encoding characteristic of the received packet, and

decode the first packet based on the at least one encoding characteristic.

13. The non-transitory processor-readable medium of claim 12, wherein the first MCS index is extracted from a signal (SIG) field of a physical layer (PHY) preamble of the first packet.

14. A method comprising:

selecting, at a transmitter, a modulation and coding scheme (MCS) from a plurality of MCSs available for use in communicating a packet via a sub-one gigahertz wireless network operating at a particular bandwidth while using a particular number of spatial streams, wherein the sub-one gigahertz wireless network supports operation at a bandwidth of one megahertz;

determining at least one encoding characteristic based on an MCS index corresponding to the selected MCS and based on one or more data structures that indicate the at least one encoding characteristic, wherein at least one of the one or more data structures indicates, for the bandwidth of one megahertz and when one spatial stream is in use;

when the MCS index is 10, a modulation scheme is binary phase-shift keying (BPSK), a number of bits per subcarrier symbol is 1, a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol is 24, and a number of data bits per OFDM symbol is 6;

inserting the MCS index into the packet;

encoding the packet based on the at least one encoding characteristic; and

sending the encoded packet via the sub-one gigahertz wireless network to a receiver.

15. A method comprising:

receiving, at a receiver, a packet sent via a sub-one gigahertz wireless network operating at a particular bandwidth while using a particular number of spatial streams, wherein the sub-one gigahertz wireless network supports operation a bandwidth of one megahertz;

extracting a modulation and coding scheme (MCS) index from the received packet;

identifying a data structure stored at the receiver, the data structure corresponding to the particular bandwidth and the particular number of spatial streams;

determining, based on the extracted MCS index and the identified data structure, at least one encoding characteristic of the received packet, wherein the identified data structure indicates, for the bandwidth of one megahertz and when one spatial stream is in use;

when the MCS index is 10, a modulation scheme is binary phase-shift keying (BPSK), a number of bits per subcarrier symbol is 1, a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol is 24, and a number of data bits per OFDM symbol is 6; and

decoding the received packet based on the at least one encoding characteristic.

16. An apparatus comprising:

a memory storing one or more data structures, the one or more data structures corresponding to one or more available bandwidths of a sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network, wherein the one or more available bandwidths of the sub-one gigahertz wireless network include a bandwidth of one megahertz, and wherein each data structure indicates, for each of a plurality of modulation and coding scheme (MCS) indexes, at least one encoding characteristic of a packet that includes the MCS index; and

a processor coupled to the memory, the processor configured to;

extract a first MCS index from a first packet received via the sub-one gigahertz wireless network operating at a first bandwidth while using a first number of spatial streams; and

determine, based on a search of the first MCS index in a first data structure of the plurality of data structures that corresponds to the first bandwidth and the first number of spatial streams, at least one encoding characteristic of the received packet, wherein the first data structure indicates, for the bandwidth of one megahertz and when one spatial stream is in use;

when the MCS index is 10, a modulation scheme is binary phase-shift keying (BPSK), a number of bits per subcarrier symbol is 1, a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol is 24, and a number of data bits per OFDM symbol is 6.

17. An apparatus comprising:

means for storing one or more data structures, the one or more data structures corresponding to one or more available bandwidths of a sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network, wherein the one or more available bandwidths of the sub-one gigahertz wireless network include a bandwidth of one megahertz, wherein each data structure indicates, for each of a plurality of modulation and coding scheme (MCS) indexes, at least one encoding characteristic of a packet that includes the MCS index, and wherein at least one of the one or more data structures indicates, for the bandwidth of one megahertz and when one spatial stream is in use;

when the MCS index is 10, a modulation scheme is binary phase-shift keying (BPSK), a number of bits per subcarrier symbol is 1, a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol is 24, and a number of data bits per OFDM symbol is 6; and

means for processing a packet based on a particular MCS index included in the packet.

18. The apparatus of claim 17, wherein the means for processing comprises an encoder configured to encode the packet based on the MCS index.

19. The apparatus of claim 17, wherein the means for processing comprises a decoder configured to decode the packet based on the MCS index.

20. The apparatus of claim 17, wherein the sub-one gigahertz wireless network operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah protocol.