Abstract: A frequency conversion system with improved performance. In one embodiment an image reject mixer is used to perform frequency conversion providing an initial degree of suppression of the image and local oscillator leakage signals, and a signal to noise enhancer (SNE) is used to further suppress the image and local oscillator signals, the signal to noise enhancer being a nonlinear passive device that attenuates low-power signals while transmitting high power signals with little loss. The signal to noise enhancer may be fabricated as a thin film of yttrium iron garnet (YIG) epitaxially grown on a gadolinium gallium garnet (GGG) substrate, the GGG substrate secured to a microwave transmission line from the input to the output of the signal to noise enhancer, such that the thin film of yttrium iron garnet is close to the transmission line.

Abstract: Techniques for adaptive backchannel equalization. A total equalization value is determined over a preselected training period. A total balance equalization value is determined over the preselected training period. A transmitter equalization coefficient is determined based on the total equalization value and the total balance equalization value. Data is transmitted over a serial link using the transmitter equalization coefficient.

Abstract: A frequency conversion system with improved performance. In one embodiment an image reject mixer is used to perform frequency conversion providing an initial degree of suppression of the image and local oscillator leakage signals, and a signal to noise enhancer (SNE) is used to further suppress the image and local oscillator signals, the signal to noise enhancer being a nonlinear passive device that attenuates low-power signals while transmitting high power signals with little loss. The signal to noise enhancer may be fabricated as a thin film of yttrium iron garnet (YIG) epitaxially grown on a gadolinium gallium garnet (GGG) substrate, the GGG substrate secured to a microwave transmission line from the input to the output of the signal to noise enhancer, such that the thin film of yttrium iron garnet is close to the transmission line.

Abstract: A method operational on a receiver device for decoding a codeword is provided. At least a portion of a composite code mask is obtained, via a receiver sensor, and projected on the surface of a target object. The composite code mask may be defined by a code layer and a carrier layer. A code layer of uniquely identifiable spatially-coded codewords may be defined by a plurality of symbols. A carrier layer may be independently ascertainable and distinct from the code layer and may include a plurality of reference objects that are robust to distortion upon projection. At least one of the code layer and carrier layer may have been pre-shaped by a synthetic point spread function prior to projection. The code layer may be adjusted, at a processing circuit, for distortion based on the reference objects within the portion of the composite code mask.

Abstract: In one embodiment, a communication device samples a particular frequency hopping sequence during only a particular specified sub-timeslot of a timeslot. If a transmission energy is not detected during the specified sub-timeslot, the device turns off its receiver for a remainder of the timeslot. Otherwise, it continues to sample the particular frequency hopping sequence for at least one or more additional sub-timeslots of the remainder of the timeslot. In another embodiment, a communication device determines whether a neighboring communication device is operating in a first mode or a second mode. If in the second mode, it transmits a transmission to the neighboring communication device starting at any sub-timeslot of the plurality of sub-timeslots. If in the first mode, it transmits the transmission to the neighboring communication device while ensuring that the transmission is actively energized during a particular specified sub-timeslot.

Abstract: Time-reversal wireless communication includes: at a base station, receiving a probe signal from a terminal device; generating a signature waveform that is based on a time-reversed signal of a channel response signal derived from the probe signal; performing quadrature amplitude modulation (QAM) on a transmit signal to generate a quadrature amplitude modulated signal; and generating a transmission signal based on the quadrature amplitude modulated signal and the signature waveform.

Abstract: An interference alignment method using multiple antennas in a multi-cell overlapped environment, includes: when at least one transmission and reception ends having at least one or more antennas communicate with each other, establishing at least one or more channels from the transmission end to the reception end. Further, the interference alignment method includes designing a processing filter for a transmission signal transmitted from the transmission end to the reception ends; and designing a processing filter for a reception signal that is received by the reception end.

Abstract: Systems and methods for despreading a received signal are described herein. In one embodiment, a vector processor comprises a plurality of code generators, wherein each code generator is configured to generate a different code corresponding to a different code hypothesis. The vector processor also comprises a plurality of despread blocks coupled to a common input for receiving samples of a signal, wherein each despread block is configured to despread at least a portion of the samples with a different one of the codes to generate respective despreaded samples and to accumulate the respective despreaded samples over a length of the code.

Abstract: A communications device may include a wireless receiver, and a processor coupled to the wireless receiver. The processor may be configured to receive a spread OFDM signal having narrowband interference associated with the same, the spread OFDM signal having subcarriers with data distributed among the subcarriers. The processor may be configured to excise the narrowband interference from the spread OFDM signal, and despread the spread OFDM signal after excising and based upon the excising to recover the data.

Abstract: Systems and methods are disclosed herein to provide communication test systems for the testing of packet data communication devices, systems and networks. According to one aspect of the subject matter described herein, a test system containing an integrated traffic, protocol and waveform analyzer is disclosed that includes a traffic generator/analyzer and a protocol engine that triggers a waveform analyzer to analyze the signal waveform of a device under test at a predetermined point. Such a test system may offer improved capabilities such as a more selective and accurate measurement of complex signal waveforms, more automated measurements of waveforms pertaining to wireless communication data streams, and more rapid identification and measurement of waveforms corresponding to errored packets.

Abstract: An apparatus, method and program for processing a signal received over a wireless channel. The apparatus comprises: a channel searcher configured to determine a profile of the channel in the form of energy values for a plurality of rays at respective channel positions, and an equalizer for equalizing the signal based on a variable window of the equalizer. The channel searcher is configured to estimate dispersion of the channel by determining a measure of variance of ray distance from a reference position within the channel profile weighted by ray energy. The equalizer is coupled to the channel searcher and arranged to adapt the window in dependence on the measure of energy-weighted ray distance variance.

Abstract: A method and apparatus for: receiving a radio frequency (RF) signal on a first channel; determining a radio signal strength of the RF signal; performing a correlation of the RF signal with a predetermined sequence of a wireless data packet to determine whether the RF signal contains the predetermined sequence; in response to the RF signal not containing the predetermined sequence, generating an indication that the RF signal is not a wireless data packet; and determining whether the radio signal strength of the RF signal exceeds a predetermined threshold. In response to i) the radio signal strength exceeding the predetermined threshold and ii) the indication being generated: measuring a parameter associated with the RF signal; determining whether the RF signal is a radar signal based on the parameter; and changing from the first channel in response to the RF signal being determined to be a radar signal.

Abstract: An optimum time domain windowing scheme for orthogonal frequency-division multiplexing (OFDM)-based waveforms in the sense of spectral concentration is proposed. Instead of evenly suppressing the sidelobes along the frequency, the sidelobe power is concentrated within a guard band while maximally suppressing the power for a desired frequency range. This is achieved by employing optimum finite duration pulses, prolate spheroidal wave functions (PSWF), to shape the OFDM transmit pulse. Also with per-subcarrier windowing scheme, the effect of inner subcarriers on sidelobes is diminished by utilizing the concentration bandwidth versus out-of-band power trade-off in PSWF and the multicarrier nature of the OFDM.

Abstract: An interference cancellation system (ICS) may be used with a communication system to prevent or minimize interference from one or more sources. The ICS may receive radio frequency (RF) signals comprised of one or more signals of interest (SOI) and multiple interfering signals. An interference estimation processor (IEP) may be used to estimate the one or more interfering signals. The interfering signals may be estimated using spatial and/or time diversity, which may be combined with statistical methods. The estimated interfering signals may be sent to the ICS, which may use the estimated interference signal to cancel the interference and output the SOI.

Abstract: The disclosure relates to a transmission scheme for nodes in a network. More specifically, the disclosure relates to an acknowledgment scheme that minimizes energy requirements for an acknowledgment of a transmission between nodes. The disclosure describes that an energy constrained node may transmit to other nodes in a network and may only require that an acknowledgment of that transmission is received from at least one of the proximal recipients, which may or may not be the ultimate target. In order to minimize the complexity of the receiver in a node and its energy requirements, the acknowledgment scheme may employ simple on-off keying (OOK) irrespective of the modulation technique of the sending transmission. The acknowledgment comprises a series of OOK pulses sent at a specified time after receipt of the transmission. In addition, simultaneously received acknowledgments can be processed and verified without confusion.

Abstract: A system and method of extracting data from data packets transmitted over a wireless network includes receiving a data packet having a preamble portion and a payload portion. The preamble portion is cross correlated with a first known spreading sequence to generate a first timing signal and the preamble portion is cross correlated with a second known spreading signal to generate a frame timing signal. An impulse is detected in the first timing signal and a first timing parameter is set based upon the detected impulse in the first timing signal. An impulse is detected in the frame timing signal and a frame timing parameter is set based upon the detected impulse in the frame timing signal. Data is extracted from the received payload portion according to the first timing parameter and the frame timing parameter.

Abstract: An electronically tunable equalizer is provided to a downlink (DL) and/or uplink (UL) signal processing path of a wireless communication unit incorporating a RF filter. The electronically tunable equalizer is pre-configured with a plurality of capacitance states, each representing a specific capacitance. The equalizer produces a different equalizer response for each of the plurality of capacitance states based on a received pass-band frequency signal. The plurality of equalizer responses is provided to the RF filter on a signaling processing path, thus affecting the RF filter's pass-band ripple. The RF filter's pass-band ripple is measured for each of the plurality of equalizer responses to determine a desired pass-band ripple. By configuring the electronically tunable equalizer to the capacitance state that produced the desired pass-band ripple, a ceramic RF filter may be used in the wireless communication unit for the benefit of lower cost and size, with reduced pass-band ripple.

Abstract: A system and method for optimally combining multi-path signals is presented. A first signal is received that traveled a first path from a transmitter to a receiving location and a second signal is received that traveled a different second path from the transmitter to the same receiving location. The paths are different so that the first and second signals contain the same signal data but the first signal has a first distortion that is different than a second distortion in the second signal. According to an objective function, the method adaptively generates a first weight value and a second weight value. The first and second weight values are applied to the respective first and second signals to produce respective first and second weighted signals. The first and second weighted signals are linearly combined producing a combined signal with a combined signal degradation.

Abstract: Various embodiments of wireless communication systems and methods in which the system seamlessly dual-uses a receiver chain for incoming transmissions and for other signal sensing purposes. The system is configured such that there are multiple receiver chains, and at least one receiver chain alternates between receiving a communication signal with information payload and receiving other signals solely for the purposes of monitoring and/or improving some aspects of the system. In various embodiments, the alternating receiver chain receives alternatively signals with information payloads and signals which have passes through a power amplifier with amplifier distortion characteristics. In various embodiments, the alternating receiver chain receives alternatively signals with information payloads and signals which may be associated with background noise, or other radio transmissions.

Abstract: In a method for determining timing information in a receiver, a receiver receives a modulated signal and demodulates the modulated signal using an demodulator to produce a demodulated signal. An analog to digital converter converts the demodulated signal to a digital signal and first and second signals are produced from the digital signal. The first signal is analyzed to determine a first phase difference with respect to different portions of the signal, and the second signal is analyzed to determine a second phase difference with respect to different portions of the second signal. The second signal is a frequency domain representation of at least a portion of the first signal. A joint estimate of a sampling period offset and a carrier frequency offset is generated based on the first phase difference and the second phase difference.