Methods and systems relating to ultra wideband broadcasting
Within many applications impulse radio based ultra-wideband (IR-UWB) transmission offers significant benefits for very short range high data rate communications when compared with existing standards and protocols. In many of these applications the main design goals are very low power consumption and very low complexity design for easy integration and cost reduction. Digitally programmable IR-UWB transmitters using an on-off keying modulation scheme on a 0.13 microns CMOS process operating on 1.2V supply and yielding power consumption as low as 0.9 mW at a 10 Mbps data rate with dynamic power control are enabled. The IR-UWB transmitters support new frequency hopping techniques providing more efficient spectrum usage and dynamic allocation of the spectrum when transmitting in highly congested frequency bands. Biphasic scrambling is also introduced for spectral line reduction. Additionally, an energy detection receiver for IR-UWB is presented to similarly meet these design goals while being adaptable to address IR-UWB transmitter specificity.
1. A transmitter for an impulse radio comprising:
a radio frequency (RF) signal generator for transmitting data, the RF signal generator receiving a data signal to be transmitted and a clock signal characterised by a clock frequency and coupled to an RF antenna and a control circuit;
the control circuit for controlling the generation of the transmitted data such that each bit being transmitted is comprised of a plurality N pulses generated by the RF signal generator 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; wherein
N≥2 and M≥2;
M and N are integers;
a pulse repetition rate of the RF signal generator is determined in dependence of the clock frequency;
the integer N depends upon a duration of a bit of the data signal and the pulse repetition rate of the RF signal generator; and
the plurality N pulses are transmitted within the duration of the bit of the data signal and comprise pulses at the plurality M frequencies.
2. The transmitter according to claim 1 , wherein
the RF signal generator employs biphasic phase scrambling such that each transmitted pulse has either a first phase and a second phase wherein the sequence of phases is pseudo-random.
3. The transmitter according to claim 2 , wherein biphasic phase scrambling within the RF generator employs either:
the generation of both phases for every pulse and selection of either the first phase or the second phase by a switch controlled by a pseudo-random control signal; or
the start-up condition of a digitally controlled oscillator forming part of the RF signal generator is pseudo-randomly affected to provide an output signal with either the first phase or the second phase.
4. The transmitter according to claim 1 , wherein
the plurality N pulses each at a predetermined frequency of the plurality M frequencies having predetermined amplitude and predetermined pulse length provide an accumulated power density spectrum from the transmitter that complies with at least one of a predetermined power spectrum mask and a maximum transmitter power within a predetermined frequency range.
5. The transmitter according to claim 1 , wherein
the plurality N pulses each at a predetermined frequency of the plurality M frequencies having predetermined amplitude and predetermined pulse length provide a predetermined accumulated power density spectrum that has a notch centered at a predetermined frequency within an emission band of the transmitter.
6. The transmitter according to claim 5 , wherein
the predetermined frequency is established in dependence upon detection by a device comprising the transmitter of another transmitter operating within the emission band of the transmitter, the another transmitter operating according to a predetermined standard.
7. The transmitter according to claim 1 , wherein
the transmitter further comprises a power management circuit such that the transmitter supports operation at a plurality of utilizations wherein at utilizations lower than 100% selected portions of the transmitter are powered down when not transmitting in order to lower the power consumption of the transmitter.
8. The transmitter according to claim 1 , wherein
the transmitter exploits at least one of an on-off keying modulation scheme and a pulse-position modulation scheme.
9. The transmitter according to claim 1 , wherein
the plurality N pulses each at a predetermined frequency of the plurality M frequencies having predetermined amplitude and predetermined pulse length provides dynamic configuration of the transmitter for each bit of data being transmitted to maximize spectral coverage and avoid interference from other transmitters.
10. The transmitter according to claim 1 , wherein
the RF signal generator provides for a transmitter that hops at least one of pulse frequency and bandwidth at the pulse repetition rate of the RF signal generator.
11. The transmitter according to claim 1 , wherein
the transmitter operates without up-conversion.
12. A transceiver for an impulse radio receiver comprising:
a radio frequency (RF) signal generator for transmitting data, the RF signal generator receiving a data signal to be transmitted and a clock signal characterised by a clock frequency and coupled to an RF antenna and a control circuit;
a radio frequency (RF) receiver chain coupled to an antenna for processing RF signals received by the antenna comprising at least an energy detection circuit; wherein
the RF receiver chain supports dynamic configuration to receive data transmitted according to a plurality of pulse based transmission schemes; and
each transmission scheme of the plurality of pulse based transmission schemes comprises transmitting data such that each bit transmitted is comprised of 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; wherein
N≥2 and M≥2;
M and N are integers;
a pulse repetition rate of the RF signal generator is determined in dependence of the clock frequency;
the integer N depends upon a duration of a bit of the data signal and the pulse repetition rate of the RF signal generator; and
the plurality N pulses are transmitted within the duration of the bit of the data signal and comprise pulses at the plurality M frequencies.
13. The transceiver according to claim 12 , further comprising a power management circuit which:
supports operation of the receiver at a plurality of utilizations wherein at utilizations lower than 100% selected portions of the receiver are powered down to lower the power consumption of the receiver;
starts an integrator forming part of the energy detection circuit during power up in a known state; and
powers up circuits within the receiver in a predetermined sequence in order to avoid voltage changes propagating through the receiver and affecting the integrator.
14. A radio system communicating over a wireless link comprising:
a transmitter supporting operation as an impulse radio comprising:
a radio frequency (RF) signal generator for transmitting data, the RF signal generator receiving a data signal to be transmitted and a clock signal characterised by a clock frequency and coupled to an RF antenna and a control circuit; and
the control circuit for controlling the generation of the transmitted data such that each bit being transmitted is comprised of 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; wherein
N≥2 and M≥2;
M and N are integers;
a pulse repetition rate of the RF signal generator is determined in dependence of the clock frequency;
the integer N depends upon a duration of a bit of the data signal and the pulse repetition rate of the RF signal generator; and
the plurality N pulses are transmitted within the duration of the bit of the data signal and comprise pulses at the plurality M frequencies; and
a receiver supporting operation as an impulse radio receiver comprising:
a radio frequency (RF) receiver chain coupled to an antenna for processing RF signals received by the antenna comprising at least an energy detection circuit; wherein
the RF receiver chain supports dynamic configuration to receive data transmitted with a plurality of pulse based transmission schemes of which the pulse based transmission of the transmitter is one such pulse based transmission scheme.
15. A device comprising:
a transmitter supporting operation as an impulse radio comprising:
a radio frequency (RF) signal generator for transmitting data, the RF signal generator receiving a data signal to be transmitted and a clock signal characterised by a clock frequency and coupled to an RF antenna and a control circuit; and
the control circuit for controlling the generation of the transmitted data such that each bit being transmitted is comprised of 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; wherein
N≥2 and M≥2;
M and N are integers;
a pulse repetition rate of the RF signal generator is determined in dependence of the clock frequency;
the integer N depends upon a duration of a bit of the data signal and the pulse repetition rate of the RF signal generator; and
the plurality N pulses are transmitted within the duration of the bit of the data signal and comprise pulses at the plurality M frequencies; and
a receiver supporting operation as an impulse radio receiver comprising:
a radio frequency (RF) receiver chain coupled to an antenna for processing RF signals received by the antenna comprising at least an energy detection circuit; wherein
the RF receiver chain supports dynamic configuration to receive data transmitted with a plurality of pulse based transmission schemes of which the pulse based transmission of the transmitter is one such pulse based transmission scheme;
a first power control circuit selectively powering up and powering down predetermined portions of the transmitter in dependence upon the data being transmitted; and
a second power control circuit selectively powering up and powering down predetermined portions of the receiver in dependence upon the data being received.
16. The device according to claim 15 , wherein
the RF signal generator employs biphasic phase scrambling such that each transmitted pulse has either a first phase and a second phase wherein the sequence of phases is pseudo-random; and
sequential pulses are at least one of different frequencies and different phases.
17. The device according to claim 15 , wherein
at least one of the plurality N pulses:
provide an accumulated power density spectrum from the transmitter that complies with a predetermined power spectrum mask;
provide an accumulated power density spectrum from the transmitter that has a maximum transmitter power within a predetermined frequency range;
provide an accumulated power density spectrum that has a notch centered at a predetermined frequency within the emission band of the transmitter; and
each have a pseudo-randomly established first phase or second phase and provide an accumulated power density spectrum from the transmitter having reduced spectral lines relative to the same plurality of N pulses without the pseudo-randomly established first phase or second phase.
18. The transceiver according to claim 12 , wherein
at least one of the plurality N pulses:
provide an accumulated power density spectrum from the transmitter that complies with a predetermined power spectrum mask;
provide an accumulated power density spectrum from the transmitter that has a maximum transmitter power within a predetermined frequency range;
provide an accumulated power density spectrum that has a notch centered at a predetermined frequency within the emission band of the transmitter; and
each have a pseudo-randomly established first phase or second phase and provide an accumulated power density spectrum from the transmitter having reduced spectral lines relative to the same plurality of N pulses without the pseudo-randomly established first phase or second phase.
19. The radio system according to claim 14 , wherein
at least one of the plurality N pulses:
provide an accumulated power density spectrum from the transmitter that complies with a predetermined power spectrum mask;
provide an accumulated power density spectrum from the transmitter that has a maximum transmitter power within a predetermined frequency range;
provide an accumulated power density spectrum that has a notch centered at a predetermined frequency within the emission band of the transmitter; and
each have a pseudo-randomly established first phase or second phase and provide an accumulated power density spectrum from the transmitter having reduced spectral lines relative to the same plurality of N pulses without the pseudo-randomly established first phase or second phase.
20. The transmitter according to claim 1 , wherein
the bit of the data signal transmitted as the plurality of N pulses within the duration of the bit of the data signal and comprising pulses at the plurality M frequencies detected by a receiver comprising an energy detection circuit without any knowledge of the timing and frequency of each pulse of the plurality of N pulses.
21. The transceiver according to claim 12 , wherein
the RF receiver chain detects each bit of the data signal transmitted as the plurality of N pulses within the duration of the bit of the data signal and comprising pulses at the plurality M frequencies without any knowledge of the timing and frequency of each pulse of the plurality of N pulses.
22. The radio system according to claim 14 , wherein
the RF receiver chain detects each bit of the data signal transmitted as the plurality of N pulses within the duration of the bit of the data signal and comprising pulses at the plurality M frequencies without any knowledge of the timing and frequency of each pulse of the plurality of N pulses.
23. The device according to claim 15 , wherein
the RF receiver chain detects each bit of the data signal transmitted as the plurality of N pulses within the duration of the bit of the data signal and comprising pulses at the plurality M frequencies without any knowledge of the timing and frequency of each pulse of the plurality of N pulses.