Energy efficient ultra-wideband impulse radio systems and methods
Ultra-Wideband (UWB) technology exploits modulated coded impulses over a wide frequency spectrum with very low power over a short distance for digital data transmission. Such UWB systems through their receivers may operate in the presence of interfering signals and should provide for robust communications. Accordingly, an accurate and sharp filter that operates at low power is required and beneficially one that does not require a highly accurate power heavy clock. Further, many UWB applications require location and/or range finding of other elements and it would therefore be beneficial to provide a UWB based range finding and/or location capability removing the requirement to add additional device complexity and, typically significant, power consumption.
1. A method comprising:
establishing a range between a pair of Ultra-Wideband (UWB) transceivers comprising a first ultra-wideband (UWB) transceiver with a second UWB transceiver using a process in execution upon the first UWB transceiver and the second UWB transceiver; wherein
the range is established in dependence upon a process in execution upon the first transceiver which employs an estimate of an elapsed time for an echo signal established by a digital signal processing (DSP) circuit forming part of the first UWB transceiver; and
the echo signal was generated by the second UWB transceiver; wherein
the first UWB transceiver and the second UWB transceiver are not synchronized with each other;
the first UWB transceiver incorporates:
a filter circuit comprising an input port electrically coupled to an antenna for receiving UWB signals and an output port where the filter circuit processes the received UWB signals to generate processed UWB signals;
a clock source; and
an energy detector circuit electrically coupled to the output port of the filter circuit and the clock source;
the DSP establishes the energy within integration time windows that are established in dependence upon a clock signal generated by the clock source; and
the estimate of the elapsed time is established in dependence upon an energy distribution determined by the DSP for two consecutive integration time windows during which the echo signal is received.
2. The method according to claim 1 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows.
3. The method according to claim 1 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows; and
the estimate of the elapsed time is established by multiplying energy distribution by the time of each integration time window.
4. A method comprising:
establishing a range between a pair of Ultra-Wideband (UWB) transceivers comprising a first ultra-wideband (UWB) transceiver with a second UWB transceiver using a process in execution upon the first UWB transceiver and the second UWB transceiver; wherein
the range is established in dependence upon a process in execution upon the first transceiver which employs an estimate of an elapsed time for an echo signal established by a digital signal processing (DSP) circuit forming part of the first UWB transceiver; and
the echo signal was generated by the second UWB transceiver; wherein
the first UWB transceiver and the second UWB transceiver are not synchronized with each other;
the first UWB transceiver incorporates an energy detector circuit;
the DSP establishes the energy within integration time windows that are established in dependence upon a clock signal generated by a clock source forming part of the first transceiver and the output of the energy detector circuit; and
the estimate of the elapsed time is established in dependence upon an energy distribution determined by the DSP for two consecutive integration time windows during which the echo signal is received.
5. The method according to claim 4 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows.
6. The method according to claim 4 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows; and
the estimate of the elapsed time is established by multiplying energy distribution by the time of each integration time window.
7. A method comprising:
establishing a range between a pair of Ultra-Wideband (UWB) transceivers comprising a first ultra-wideband (UWB) transceiver with a second UWB transceiver using a process in execution upon the first UWB transceiver and the second UWB transceiver; wherein
the range is established in dependence upon a process in execution upon the first transceiver which employs an estimate of an elapsed time for an echo signal established by a digital signal processing (DSP) circuit forming part of the first UWB transceiver; and
the echo signal was generated by the second UWB transceiver; wherein the process comprises:
transmitting an ultra-wideband (UWB) impulse with the first UWB transceiver operating with a first clock rate having first integration windows in dependence upon the first clock rate;
receiving from the second UWB transceiver the echo signal which was generated by the second UWB transceiver in dependence upon its receipt of the UWB impulse;
integrating received UWB signals within the first integration windows and determining when the received energy within a first integration window exceeds a predetermined threshold that the echo signal has been received;
passing the integrated energies within the first integration windows to the digital signal processing (DSP) circuit; and
establishing the estimate of elapsed time with the DSP circuit.
8. The method according to claim 7 , wherein
the first UWB transceiver and the second UWB transceiver are not synchronized with each other;
the first UWB transceiver incorporates an energy detector circuit; and
the estimate of the elapsed time is established in dependence upon an energy distribution determined by the DSP for two consecutive first integration windows during which the echo signal is received.
9. The method according to claim 8 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows.
10. The method according to claim 8 , wherein
the energy distribution is established by dividing the energy within a second integration time window of the two consecutive integration time windows by the sum of the two consecutive integration time windows; and
the estimate of the elapsed time is established by multiplying energy distribution by the time of each integration time window.
11. The method according to claim 7 , wherein
the echo signal is generated by the second UWB transceiver through a process comprising
receiving the UWB impulse at the second UWB transceiver which is operating with a second clock rate having second integration windows in dependence upon the second clock rate;
integrating received UWB signals within the second integration windows and determining when the received energy within a second integration window exceeds a predetermined threshold that the UWB impulse has been received; and
transmitting in the next second integration window after a determination of receipt of the UWB impulse the echo signal.
12. The method according to claim 7 , wherein
the first UWB transceiver and the second UWB transceiver are not synchronized with each other;
the first UWB transceiver incorporates an energy detector circuit;
the estimate of the elapsed time is established in dependence upon an energy distribution determined by the DSP for two consecutive first integration windows during which the echo signal is received; and
the UWB impulse comprises a plurality N pulses; wherein each pulse of the N pulses is at a predetermined frequency of a plurality M frequencies, has a predetermined amplitude, and has a predetermined pulse length; and
the echo signal comprises a plurality R pulses; wherein each pulse of the R pulses is at a predetermined frequency of a plurality S frequencies, has a predetermined amplitude, and has a predetermined pulse length.
13. The method according to claim 7 , wherein
the first UWB transceiver and the second UWB transceiver are not synchronized with each other;
the first UWB transceiver incorporates an energy detector circuit;
the estimate of the elapsed time is established in dependence upon an energy distribution determined by the DSP for two consecutive first integration windows during which the echo signal is received; and
the UWB impulse comprises a plurality N pulses; wherein each pulse of the N pulses is at a predetermined frequency of a plurality M frequencies, has a predetermined amplitude, and has a predetermined pulse length;
the echo signal comprises a plurality R pulses; wherein each pulse of the R pulses is at a predetermined frequency of a plurality S frequencies, has a predetermined amplitude, and has a predetermined pulse length; and
N, M, R, and S are positive integers greater than or equal to 2.