Phase rotation for preambles within multiple user, multiple access, and/or MIMO wireless communications
View Patent ↗Phase rotation for preambles within multiple user, multiple access, and/or MIMO wireless communications. An appropriately designed phase rotation vector and/or appropriately designed cyclic shift delays (CSDs) are applied to respective sub-band components of the preamble. With appropriately designed CSDs, certain fields within the preamble are not modified. For example, a legacy short training field (L-STF) of the preamble is not changed when using appropriately designed CSDs. The respective CSDs may be implemented as integer multiples of a common CSD (e.g., 0×CSD, 1×CSD, 2×CSD, etc. such that one of the values of such a CSD vector may be zero [0], another may be the common CSD itself, etc.). Also, by employing an appropriately designed phase rotation vector and integer multiples of a CSD to a preamble, the respective peak to average power ratio (PAPR) between different respective fields within the preamble may be minimized.
1. A wireless communication device comprising:
a communication interface; and
a processor configured to:
select a phase rotation vector from a plurality of phase rotation vectors and a plurality of integer multiples of a cyclic shift delay (CSD) that, when applied to a preamble, cooperatively reduce peak to average power ratio (PAPR) between at least two fields within the preamble;
apply a plurality of elements of the phase rotation vector respectively to a plurality of sub-band components of the preamble to generate a first modified preamble, wherein each of the plurality of elements of the phase rotation vector is applied to a respective one of the plurality of sub-band components of the preamble;
apply the plurality of integer multiples of the CSD respectively to at least some of the plurality of sub-band components of the first modified preamble to generate a second modified preamble, wherein each of the plurality of integer multiples of the CSD is applied to a respective one of the plurality of sub-band components of the first modified preamble, wherein each of the plurality of sub-band components of the preamble includes a common, uniform bandwidth, and wherein the phase rotation vector and the plurality of integer multiples of the CSD cooperatively reduce PAPR between a legacy short training field (L-STF) and at least one additional field within the second modified preamble; and
transmit, via the communication interface, a signal that includes the second modified preamble to another wireless communication device.
2. The apparatus of claim 1 , wherein the phase rotation vector is [1, j] and wherein the processor is further configured to:
apply a first CSD of 0 ns to a first sub-band component of the first modified preamble; and
apply a second CSD of 800 ns to a second sub-band component of the first modified preamble.
3. The apparatus of claim 1 , wherein the phase rotation vector is [1, j, −1, −j] and wherein the processor is further configured to:
apply a first CSD of 0 ns to a first sub-band component of the first modified preamble;
apply a second CSD of 800 ns to a second sub-band component of the first modified preamble;
apply a third CSD of 1600 ns to a third sub-band component of the first modified preamble; and
apply a fourth CSD of 2400 ns to a fourth sub-band component of the first modified preamble.
4. A method for execution by a wireless communication device, the method comprising:
selecting a phase rotation vector from a plurality of phase rotation vectors and a plurality of integer multiples of a cyclic shift delay (CSD) that, when applied to a preamble, cooperatively reduce peak to average power ratio (PAPR) between at least two fields within the preamble;
applying a plurality of elements of the phase rotation vector respectively to a plurality of sub-band components of the preamble to generate a first modified preamble, wherein each of the plurality of elements of the phase rotation vector is applied to a respective one of the plurality of sub-band components of the preamble;
applying the plurality of integer multiples of the CSD respectively to at least some of the plurality of sub-band components of the first modified preamble to generate a second modified preamble, wherein each of the plurality of integer multiples of the CSD is applied to a respective one of the plurality of sub-band components of the first modified preamble; and
transmitting, via a communication interface of the wireless communication device, a signal that includes the second modified preamble to another wireless communication device.
5. The method of claim 4 further comprising:
applying a first CSD of 0 ns to a first sub-band component of the first modified preamble; and
applying a second CSD of 800 ns to a second sub-band component of the first modified preamble.
6. The method of claim 4 , wherein the phase rotation vector is [1, j].
7. The method of claim 4 further comprising:
applying a first CSD of 0 ns to a first sub-band component of the first modified preamble;
applying a second CSD of 800 ns to a second sub-band component of the first modified preamble;
applying a third CSD of 1600 ns to a third sub-band component of the first modified preamble; and
applying a fourth CSD of 2400 ns to a fourth sub-band component of the first modified preamble.
8. The method of claim 4 , wherein the phase rotation vector is [1, j, −1, −j].
9. The method of claim 4 , wherein each of the plurality of sub-band components of the preamble having a common, uniform bandwidth.
10. The method of claim 4 further comprising:
selecting the phase rotation vector and the plurality of integer multiples of the CSD operative to reduce PAPR between a legacy short training field (L-STF) and at least one additional field within the second modified preamble.
11. The method of claim 4 , wherein the wireless communication device includes an access point (AP), and the at least one additional wireless communication device includes a wireless station (STA).
12. The method of claim 4 , wherein the wireless communication device includes a first wireless station (STA), and the at least one additional wireless communication device includes a second STA.
13. A wireless communication device comprising:
a communication interface; and
a processor configured to:
select a phase rotation vector from a plurality of phase rotation vectors and a plurality of integer multiples of a cyclic shift delay (CSD) that, when applied to a preamble, cooperatively reduce peak to average power ratio (PAPR) between at least two fields within the preamble;
apply a plurality of elements of the phase rotation vector respectively to a plurality of sub-band components of the preamble to generate a first modified preamble, wherein each of the plurality of elements of the phase rotation vector is applied to a respective one of the plurality of sub-band components of preamble;
apply the plurality of integer multiples of the CSD respectively to the plurality of sub-band components of the first modified preamble to generate a second modified preamble, wherein each of the plurality of integer multiples of the CSD is applied to a respective one of the plurality of sub-band components of the first modified preamble; and
transmit, via the communication interface, a signal that includes the second modified preamble to another wireless communication device.
14. The apparatus of claim 13 , wherein the processor is further configured to:
apply a first CSD of 0 ns to a first sub-band component of the first modified preamble; and
apply a second CSD of 800 ns to a second sub-band component of the first modified preamble.
15. The apparatus of claim 13 , wherein the phase rotation vector being [1, j].
16. The apparatus of claim 13 , wherein the processor is further configured to:
apply a first CSD of 0 ns to a first sub-band component of the first modified preamble;
apply a second CSD of 800 ns to a second sub-band component of the first modified preamble;
apply a third CSD of 1600 ns to a third sub-band component of the first modified preamble; and
apply a fourth CSD of 2400 ns to a fourth sub-band component of the first modified preamble.
17. The apparatus of claim 13 , wherein the phase rotation vector is [1, j, −1, −j].
18. The apparatus of claim 13 , wherein each of the plurality of sub-band components of the preamble having a common, uniform bandwidth.
19. The apparatus of claim 13 , wherein the processor is further configured to:
select the phase rotation vector and the plurality of integer multiples of the CSD operative to reduce PAPR between a legacy short training field (L-STF) and at least one additional field within the second modified preamble.
20. The apparatus of claim 13 further comprising:
an access point (AP), wherein the wireless communication device includes a wireless station (STA).
21. The apparatus of claim 13 further comprising:
a first wireless station (STA), wherein the wireless communication device being a second STA.