Methods and apparatuses are presented to reduce multiuser interference resulting from two or more overlapping ultra wideband (UWB) transmissions by randomizing the start time of packets and/or bursts within the packets. A random offset time may be generated for a packet, and transmission of the packet may be arbitrarily delayed by that random offset time, relative to an earlier time at which the packet is prepared for transmission. A random offset time may be generated for a pulse burst within a symbol of a packet, and transmission of the burst may be delayed by that random offset time, relative to a nominal transmission window within the symbol. The burst may therefore occupy a portion of a guard period following the nominal transmission window. Either procedure, or both procedures, may be used to reduce multiuser interference between two concurrently transmitted packets by randomizing overlap occurring between the bursts.

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 whilst being adaptable to address IR-UWB transmitter specificity.

A method for the detection of a pulse of a signal received by a receiver device, the received signal corresponding to data emitted with a predetermined period T.sub.c, each piece of data being encoded by a presence or an absence of a pulse. The method includes: temporally offsetting of the received signal according to a predetermined number N.sub.s of delays corresponding to different multiples of T.sub.c, so as to generate N.sub.s delayed signals; correlating, at a time that is a candidate for the detection of a pulse, the received signal with each of the delayed signals, in so as to obtain N.sub.s correlation values associated with the candidate time; calculating a maximum correlation value among the N.sub.s correlation values associated with the candidate time; and

detecting a pulse of the received signal according to the maximum correlation value.

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 whilst being adaptable to address IR-UWB transmitter specificity.

Methods and apparatuses are presented to reduce multiuser interference resulting from two or more overlapping ultra wideband (UWB) transmissions by randomizing the start time of packets and/or bursts within the packets. A random offset time may be generated for a packet, and transmission of the packet may be arbitrarily delayed by that random offset time, relative to an earlier time at which the packet is prepared for transmission. A random offset time may be generated for a pulse burst within a symbol of a packet, and transmission of the burst may be delayed by that random offset time, relative to a nominal transmission window within the symbol. The burst may therefore occupy a portion of a guard period following the nominal transmission window. Either procedure, or both procedures, may be used to reduce multiuser interference between two concurrently transmitted packets by randomizing overlap occurring between the bursts.

Embodiments enable communicating Ultra Wideband (UWB) devices to collaborate by exchanging pulse shape information. The UWB devices use the pulse shape information to improve ranging accuracy. The improved ranging accuracy can be used in complex multipath environments where advanced estimation schemes are used to extract an arriving path for time-of-flight estimation. To determine the pulse shape information to be shared, some embodiments include determining location information of a UWB device and selecting the pulse shape information that satisfies regional aspects. The pulse shape information includes a time-zero index specific to a ranging signal that is used by UWB receivers to establish timestamps time-of-flight calculations. Some embodiments include measuring performance characteristics and selecting different pulse shape information based on the performance characteristics for improved accuracy.

In ultra-wideband or impulse radio terahertz wireless communication, the electromagnetic signal may experience group delay dispersion (GDD). Without correction, this can degrade the achievable data transmission rate. An apparatus comprising a stratified structure having a front portion and a back portion is disclosed. The structure comprises a plurality of adjacent layers of differing refractive indices, wherein each layer has a refractive index different from an immediately adjacent layer. The structure further includes a backing layer at the back portion. The structure defines a GDD, which can be adjusted, and the structure is configured to introduce the GDD to an incident electromagnetic signal and thereby produce a dispersion-compensated electromagnetic signal when the incident signal is reflected by the structure. The GDD of the structure is configured to substantially cancel out the dispersive effects experienced by the electromagnetic signal in the signal path.

A method for activating a vehicle function, by an activation device including a transceiver to communicate with hands-free access equipment. The transceiver is equipped with a gyroscope and a magnetometer and two receiving antennas that have a coefficient of electromagnetic coupling between them that is below a threshold. The method includes the following steps for at least two consecutive footsteps: transmission of a signal comprising data of the gyroscope and the magnetometer of the hands-free equipment to the vehicle; comparison of the data with representative values of the gyroscope and the magnetometer of the transceiver; determination of a first direction of the user; determination of a second direction of the user based on an estimation of a first angle of arrival of the signal towards the transceiver; comparison of the first direction and the second direction; activation of the vehicle function on the basis of the result of the comparison.

Methods, systems, and apparatuses are presented to transmit fragmented communication frames, such as fragmented ultra-wideband (UWB) frames. In some implementations, a communication frame may be divided into a plurality of fragments, and the fragments may be transmitted across a plurality of regulatory test intervals. E.g., each fragment may be transmitted within a mutually-exclusive regulatory test interval. In some implementations, each fragment may be constrained in time and/or transmission power, such that the total energy emitted during transmission of the fragment remains within a maximum energy limit defined for the regulatory test interval, e.g., by a regulatory entity. In some implementations, the sum of the energy emitted during transmission of two or more fragments may exceed the maximum energy limit defined for the regulatory test interval.

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 1.2 V 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.