Abstract: An angle of arrival system is configured to efficiently measure phase differences. The angle of arrival system includes a master receiver for demodulating the signal received at one antenna and for implementing a tracking loop to identify the timing of symbols within the signal. This timing information can be fed back as a synchronization signal to a despreader in the master receiver and to a despreader in each of a number of slave receivers to synchronize the timing at which each signal is despread. Because despreading is synchronized, the outputs of the despreaders can be used to directly calculate phase differences between each pair of signals. In this way, the slave receivers do not need to implement a demodulator or a tracking loop. When the received signal is a non-spread signal, the phase differences between each pair of signals can be calculated directly from the modulated samples of each pair of signals without despreading.

Abstract: An angle of arrival system is configured to efficiently measure phase differences. The angle of arrival system includes a master receiver for demodulating the signal received at one antenna and for implementing a tracking loop to identify the timing of symbols within the signal. This timing information can be fed back as a synchronization signal to a despreader in the master receiver and to a despreader in each of a number of slave receivers to synchronize the timing at which each signal is despread. Because despreading is synchronized, the outputs of the despreaders can be used to directly calculate phase differences between each pair of signals. In this way, the slave receivers do not need to implement a demodulator or a tracking loop. When the received signal is a non-spread signal, the phase differences between each pair of signals can be calculated directly from the modulated samples of each pair of signals without despreading.

Abstract: An antenna system can impart orbital angular momentum (OAM) to an incident electromagnetic (EM) signal from a feed antenna. The antenna system can include a partial OAM antenna with a reflective surface that has only part of a full OAM shaped surface. The antenna system can thus reflect the incident EM signal as a partial OAM beam rather than a full OAM beam.

Abstract: Electromagnetic (EM) feeds can illuminate a standard primary reflective antenna with a plurality of feed beams each having a different orbital angular momentum (OAM) or polarization. The reflective antenna, which can be a non-OAM antenna, can reflect the feed beams and thereby produce a composite OAM transmission comprising each of the feed beams. A non-OAM primary antenna can thus transmit a plurality of OAM feed beams as a composite OAM transmission.

Abstract: A transmit antenna or antennas can be configured to transmit a composite orbital angular momentum (OAM) radio frequency (RF) beam comprising a plurality of individual OAM RF signals each having a different OAM mode. An array of antennas for receiving and resolving the composite OAM beam into the individual OAM signals can be located entirely within a relatively small sector of a far field pattern of the composite OAM beam. A processing module connected to the antennas of the receive array can resolve the composite OAM beam into its individual OAM signals using angular resolution. The transmit antenna can transmit the individual OAM signals—and thus the composite OAM beam—as full OAM signals or partial-beam OAM signals.

Abstract: The present invention is directed to a decision feedback equalizer that implements a multipath delay calculator to determine the delay between a line-of-sight component of a received data signal and a reflection of the line-of-sight component. The determined delay is used to control when decisions are used within the decision feedback equalizer so that the appropriate decisions are delayed until the reflection is received. In this way, the reflection can be substantially removed from the data signal using decisions that were generated when the line-of-sight component was received. Because the correction window is limited to the time when the reflection is received, the number of taps required to perform equalization is greatly reduced resulting in a decision feedback equalizer with less circuitry or logic.

Abstract: Wireless terminals, systems, and methods use interlaced diplexers. A first diplexer can provide a first pair of bands separated by a first separation band, and a second diplexer can provide a second pair of bands separated by a second separation band. The first separation band and the second separation band can overlap. Transceivers (comprising transmitters and receivers) can be coupled to the diplexers to provide frequency-division duplex communications using one or both of the pairs of bands.

Abstract: In one exemplary embodiment, an antenna arrangement includes: a substrate; and a plurality of dipole antenna elements disposed on the substrate, wherein the plurality of dipole antenna elements are randomly-oriented with respect to each other. In further exemplary embodiments, the plurality of dipole antenna elements includes at least six dipoles that are all electrically fed and do not need to be magnetically fed in order to generate and detect an arbitrary polarization. In still further exemplary embodiments, each dipole element has a fractal shape.

Abstract: A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.

Abstract: Communication of data over a multiple-input multiple-output (MIMO) channel includes allocating transmission power unequally to the different data streams. The transmission power allocation is performed without regard to a state of a changing channel response of the MIMO channel. A relatively low complexity interference cancelling receiver can therefore decode the data streams.

Abstract: A method is disclosed for PN correlation and symbol synchronization of a spread spectrum signal at a receiver when a symbol boundary of the spread spectrum signal is not on a PN epoch or is otherwise unknown. The method includes the operation of modulating the spread spectrum signal with a PN code to form a potentially despread signal. The potentially despread signal can be integrated for a plurality of symbol times at a rate of N integrations per symbol time to form N symbol energies per symbol for a plurality of symbols. Each of the N symbol energies can correspond to a different symbol time hypothesis. The N symbol energies from the plurality of symbols can be added respectively to form N summed symbol time hypotheses. The Nth summed symbol time hypothesis having maximum power can be found. The Nth summed symbol time hypothesis can relate to a location of the symbol boundary.

Abstract: A method and system for managing Priority Messages in a hybrid TDMA-Spread Spectrum (TDMA-SS) communication system is provided. The method and system include a HUB for generating a HUB TDMA epoch, wherein the HUB TDMA epoch includes at least one Priority Message (PM) slot. The PM slot includes a plurality of assignable PM sub-slots. The method and system also include at least one SPOKE, wherein the at least one SPOKE is adapted to transmit a Priority Message during its assigned PM sub-slot within the HUB TDMA epoch.

Abstract: A receiver (20) for performing timing recovery over at least one complex channel at low or less than zero SNR (signal power to noise power, in dB) has at least one receive element such as an antenna, an analog-to-digital converter 21 (ADC), a fractional interpolation filter 23, a matched filter 24, and a timing correction loop 26. The timing correction loop 26 selects a minimum mean square error from the output of the matched filter 24 to determine a timing signal output to the interpolation filter 23, and provides one-bit weights to the matched filter 24. Preferably, the timing correction loop 26 includes a magnitude detector 26c, a moving average filter 26b, and a timing error detector 26a that outputs an integer m and fractional ? timing factor to the interpolation filter 23. Within a phase correction loop 27 is a maximum likelihood channel estimator 27b and a phase error detector 27a that controls a phase rotator 22 disposed between the ADC 21 and the interpolation filter 23.

Abstract: A system and method for using Psuedo-Noise (PN) phase to determine frame start of a data frame is provided. The system and method includes at least two PN component codes, wherein the at least two PN component codes are relatively prime. A received PN composite encoded signal is correlated with at least one of the PN component codes and a frame start is determined. With reference to frame start at least one training sequence bit is located. The training bits may be overwritten on FEC encoded frame data such that a FEC decoder may be used to recover data overwritten by the training sequence bit(s).

Abstract: A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.

Abstract: A high speed demodulator system is comprised of an analog to digital converter (ADC); a high speed demultiplexer connected to an input of the ADC; a bank of parallel programmable demodulators connected to an output of the high speed demultiplexer; a timing interface connected to the bank of parallel programmable demodulators; and a phase reference interface connected to the bank of parallel programmable demodulators and a data processor. A parallel programmable demodulator includes a reconfigurable FIR filter, has an input port for receiving digital input signals and an output coupled to a coherent signal processor and a coherent memory. The programmable FIR filter provides filtered signals to the coherent signal processor for storage in the coherent memory. The integrated circuit further includes a sequential weight processor having an input coupled to an output of the coherent memory.