Systems and methods to reduce peak to average power ratio for dual sub-carrier modulated transmissions in a wireless network
A system includes a modulator to modulate data using Quadrature Phase Shift Keying modulation and dual sub-carrier modulation to generate modulated symbols for transmission on a plurality of subcarriers. A repetition module repeats the modulated symbols from a first half of the plurality of subcarriers to a second half of the plurality of subcarriers. A phase rotation module rotates phase of the modulated symbols on selected subcarriers of the second half of the plurality of subcarriers. The selected subcarriers include all of the second half of the plurality of subcarriers. The phase rotation module rotates the phase of the modulated symbols on all of the second half of the plurality of subcarriers to conjugate the modulated symbols on all of the second half of the plurality of subcarriers relative to corresponding modulated symbols on all of the first half of the plurality of subcarriers.
1. A system comprising:
a modulator to (i) modulate data using a first modulation scheme and dual sub-carrier modulation, wherein the dual sub-carrier modulation modulates the same information on a pair of subcarriers, and (ii) generate modulated symbols for transmission on a plurality of subcarriers;
a repetition module to repeat the modulated symbols from a first half of the plurality of subcarriers to a second half of the plurality of subcarriers; and
a phase rotation module to rotate phase of the modulated symbols on selected subcarriers of the second half of the plurality of subcarriers,
wherein the selected subcarriers of the second half of the plurality of subcarriers include all of the second half of the plurality of subcarriers.
2. The system of claim 1 wherein the first modulation scheme is selected from a group consisting of Quadrature Phase Shift Keying (QPSK), Binary Phase Shift Keying (BPSK), and Quadrature Amplitude Modulation (QAM).
3. The system of claim 1 wherein the phase rotation module is configured to rotate the phase of the modulated symbols on all of the second half of the plurality of subcarriers to conjugate the modulated symbols on all of the second half of the plurality of subcarriers relative to corresponding modulated symbols on all of the first half of the plurality of subcarriers.
4. The system of claim 1 , wherein the modulator is configured to modulate the data for a signal field of a high efficiency packet.
5. The system of claim 1 , wherein the modulator is configured to modulate the data for a data field of a high efficiency packet.
6. The system of claim 1 , wherein the modulator is configured to map the modulated symbols to the plurality of subcarriers according to the first modulation scheme used with the dual sub-carrier modulation.
7. The system of claim 1 , further comprising an encoder to encode the data using a binary convolutional code or a low density parity check code selected based on a number of the plurality of subcarriers.
8. The system of claim 1 , further comprising an interleaver to interleave the data using a lesser number of columns than a number of columns specified in 802.11n and 802.11ac specifications of Institute of Electrical and Electronics Engineers (IEEE).
9. The system of claim 1 , further comprising an interleaves to interleave the data using a parameter based on a number of bits assigned to a single axis in a constellation point in a spatial stream, wherein the parameter is equal to a maximum of 1 and a number of coded bits per subcarrier in the data.
10. A method comprising:
modulating data using a first modulation scheme and dual sub-carrier modulation to generate modulated symbols for transmission on a plurality of subcarriers, wherein the dual sub-carrier modulation modulates the same information on a pair of subcarriers;
repeating the modulated symbols from a first half of the plurality of subcarriers to a second half of the plurality of subcarriers;
selecting all of the second half of the plurality of subcarriers; and
rotating phase of the modulated symbols on selected subcarriers of the second half of the plurality of subcarriers.
11. The method of claim 10 further comprising selecting the first modulation scheme from a group consisting of Quadrature Phase Shift Keying (QPSK), Binary Phase Shift Keying (BPSK), and Quadrature Amplitude Modulation (CLAM).
12. The method of claim 10 wherein rotating the phase of the modulated symbols on the selected subcarriers of the second half of the plurality of subcarriers includes rotating the phase of the modulated symbols on all of the second half of the plurality of subcarriers to conjugate the modulated symbols on all of the second half of the plurality of subcarriers relative to corresponding modulated symbols on all of the first half of the plurality of subcarriers.
13. The method of claim 10 , wherein the modulating comprises modulating the data for a signal field of a high efficiency packet.
14. The method of claim 10 , wherein the modulating comprises modulating the data for a data field of a high efficiency packet.
15. The method of claim 10 , further comprising mapping the modulated symbols to the plurality of subcarriers according to the first modulation scheme used with the dual sub-carrier modulation.
16. The method of claim 10 , further comprising encoding the data using a binary convolutional code or a low density parity check code selected based on a number of the plurality of subcarriers.
17. The method of claim 10 , further comprising interleaving the data using a lesser number of columns than the number of columns specified in 802.11n and 802.11ac specifications of Institute of Electrical and Electronics Engineers (IEEE).
18. The method of claim 10 , further comprising interleaving the data using a parameter based on a number of bits assigned to a single axis in a constellation point in a spatial stream, wherein the parameter is equal to a maximum of 1 and a number of coded bits per subcarrier in the data.