Ultrasonic communication between devices
View Patent ↗Implementations generally relate to ultrasonic communication between devices. In some implementations, a method includes receiving a data signal, where the data signal is transmitted and received in an indoor environment. The method further includes demodulating the data signal based on direct sequence spread spectrum.
1. A method comprising:
receiving a data signal, wherein the data signal is transmitted and received in an indoor environment; and
demodulating the data signal based on direct sequence spread spectrum, wherein the demodulating of the data signal comprises:
detecting a first symbol of the data signal;
partitioning the first symbol into a plurality of chunks;
approximating cross-correlation of each chunk, wherein the approximating is based on the partitioning of the first symbol into the plurality of chunks;
downconverting the data signal; and
despreading the downconverted data signal.
2. The method of claim 1 , wherein the data signal has a pedestal component.
3. The method of claim 1 , wherein the data signal is ultrasonic.
4. The method of claim 1 , wherein the demodulating of the data signal further comprises immediately acquiring synchronization of the data signal based on the approximated cross-correlation of the first symbol of the data signal.
5. The method of claim 1 , wherein the data signal has a pedestal component, and wherein the pedestal component offsets the data signal by a constant offset.
6. The method of claim 1 , wherein the approximating of the cross-correlation is based on a constant phase over each chunk.
7. The method of claim 1 , further comprising determining a frequency uncertainty for a plurality of frequencies based on the approximated cross-correlation.
8. The method of claim 1 , wherein the demodulating of the data signal comprises:
detecting a pedestal component in the data signal;
correlating the pedestal; and
determining which phase to measure data symbol wave correlations.
9. A system comprising:
one or more processors; and
logic encoded in one or more tangible media for execution by the one or more processors and when executed operable to perform operations comprising:
receiving a data signal, wherein the data signal is transmitted and received in an indoor environment; and
demodulating the data signal based on direct sequence spread spectrum, wherein the demodulating the data signal comprises:
detecting a first symbol of the data signal;
partitioning the first symbol into a plurality of chunks;
approximating cross-correlation of each chunk, wherein the approximating is based on the partitioning of the first symbol into the plurality of chunks;
downconverting the data signal; and
despreading the downconverted data signal.
10. The system of claim 9 , wherein the data signal has a pedestal component.
11. The system of claim 9 , wherein the data signal is ultrasonic.
12. The system of claim 9 , wherein, to demodulate the data signal, the logic when executed is further operable to perform operations comprising immediately acquiring synchronization of the data signal based on the approximated cross-correlation of the first symbol of the data signal.
13. The system of claim 9 , wherein the data signal has a pedestal component, and wherein the pedestal component offsets the data signal by a constant offset.
14. The system of claim 9 , wherein the approximating of the cross-correlation is based on a constant phase over each chunk.
15. The system of claim 9 , wherein the logic when executed is further operable to perform operations comprising determining a frequency uncertainty for a plurality of frequencies based on the approximated cross-correlation.