Abstract: In embodiments, a communication node of a multi-node communication network includes a controller communicatively coupled to a communication interface, wherein the controller is configured to: acquire a data payload to be transmitted based on a randomized transmission interval; duplicate a bit sequence of the data payload with a selected spreading pattern; perform bit-to-symbol mapping of the bit sequence based on a selected M-ary number to generate a data payload symbol sequence; randomize a location or value of one or more pilot symbols and one or more data carriers of the data payload symbol sequence; transform frequency-domain symbols of the data payload symbol sequence into time-domain symbols to generate a time-domain data payload signal; remove amplitude fluctuation of the data payload signal to generate a phasor data payload signal; and transmit the phasor data payload signal to at least one additional communication node of the multi-node communication network.

Abstract: A mobile radio has more than one channel, each channel corresponding to a programmable transceiver circuit. The mobile radio also includes at least one high gain antenna coupled to at least one of the programmable transceiver circuits. A location determining circuit is configured to determine the location of the mobile radio. A processor is coupled to the transceivers and to the location determining circuit. The processor runs a program logic that is configured to identify whether the mobile radio is in a location that enables the mobile radio to extend the reach of the network both due to its location and due to the use of the at least one high gain antenna. The processor also runs a program logic to carry out spectrum sensing to identify available spectral resources based on communication traffic on various frequency bands.

Abstract: Disclosed is an apparatus for estimating the features of a radio frequency signal including a reference signal generator configured for generating a reference signal from a complex signal and one or more feature estimation units configured to generate one or more feature estimates from the reference signal and the complex signal. Techniques for creating reference signals from both signals spread by a scrambling code and FM signals are discussed.

Abstract: An apparatus and method for signal separation and SINR improvement is disclosed. In particular, disclosed is an iterative technique whereby a noisy signal, that may include signals from one or more distinct emitters, is first improved through an SINR improvement technique. Next, one signal from the noisy signal is identified and a reference signal substantially free of noise and interference is generated for this signal, and then this reference signal is subtracted from the noisy signal. This process is repeated until no other signals may be identified. In this way, the signal with the highest SINR may be identified first and then removed from the original signal. As such, the identified signal is no longer present as interference for the remaining signals, thus improving each of the remaining signals' respective SINRs.

Abstract: An apparatus for identifying a specific emitter in the presence of noise and/or interference is disclosed. The apparatus includes a sensor configured to sense radio frequency signal data, the signal data containing noise and signal from at least one emitter, a reference estimation unit configured to estimate a reference signal relating to the signal transmitted by one emitter, a feature estimation unit configured to generate one or more estimates of one or more feature from the reference signal and the signal transmitted by that particular emitter, and an emitter identifier configured to identify the signal transmitted by that particular emitter as belonging to a specific device using one or more feature estimates. The emitter identifier identifies the signal transmitted by that particular emitter as belonging to a specific device using Gaussian Mixture Models and the Bayesian decision engine.

Abstract: The present disclosure is directed to a system and method for providing directional spectral awareness via an antenna system which includes a single parasitic antenna and a processor, the processor being communicatively coupled with the parasitic antenna. The antenna system allows for quick scanning of all sectors included in a plurality of sectors of an RF environment being monitored by the antenna system. The antenna system also allows for monitoring sectors of interest. The directionality of the parasitic antenna of the antenna system may reduce interference and multipath along with providing improved SNR due to antenna gain, thereby allowing for collection of signals of interest in a more favorable environment, thereby enabling analysis such as frequency and spatial use, signal detection, signal identification, and source geolocation to succeed when it may have failed if an omni-directional antenna were used.

Abstract: An apparatus for identifying a specific emitter in the presence of noise and/or interference is disclosed. The apparatus includes a sensor configured to sense radio frequency signal data, the signal data containing noise and signal from at least one emitter, a reference estimation unit configured to estimate a reference signal relating to the signal transmitted by one emitter, a feature estimation unit configured to generate one or more estimates of one or more feature from the reference signal and the signal transmitted by that particular emitter, and an emitter identifier configured to identify the signal transmitted by that particular emitter as belonging to a specific device using one or more feature estimates. The emitter identifier identifies the signal transmitted by that particular emitter as belonging to a specific device using Gaussian Mixture Models and the Bayesian decision engine.

Abstract: A spread spectrum communication system includes a transceiver configured to transmit a spread spectrum waveform. The spread spectrum waveform comprises transmitted signals at varying frequencies within a radio frequency spectrum of operation. The frequency variation is controlled according to a hopping sequence. A spectral sensor of the communication system is configured to dynamically scan the radio frequency spectrum of operation and to generate channel occupancy data based upon the scans. A real time hopping sequence generator is configured to dynamically generate the hopping sequence in real time as a function of the channel occupancy data.

Abstract: A method for transmitting data from a transmitter to a receiver in an ad hoc large scale directional network includes the followings steps. A first training sequence is sent by a transmitter in an ad hoc directional network. The first training sequence is received by a receiver in the ad hoc directional network. The receiver determines a first apparent direction from which the first training sequence is sent. The receiver sends a second training sequence to the transmitter. The transmitter determines a second apparent direction from which the second training sequence is sent. The transmitter directs a signal with the first training sequence to the receiver. The transmitter sends the signal with the first training sequence to the receiver. The receiver receives the first training sequence. The receiver is directed to the first apparent direction to receive the signal.

Abstract: A method of correlating a signal to a synchronization pattern is disclosed. The signal has a waveform with frequency and phase angle components that may be varied, at each repeated signal pulse, to communicate a change in a bit pattern of the signal. A synchronization pattern is generated using knowledge of phase rotation direction due to two consecutive bits in a synchronization key. The signal is compared with the synchronization pattern. It is determined whether the comparison of the signal and the synchronization pattern indicate a correlation between the signal and the synchronization pattern.

Abstract: An orthogonal frequency division multiplexing (OFDM) communications system transmits data on a plurality of subcarriers and has a featureless synchronization signal. The OFDM communications system transmits synchronization tones on pseudorandomly selected subcarriers. A receiver generates the same synchronization tones and performs a correlation on the received signal with the receiver synchronization tones. The correlation is performed at the beginning and the end of the synchronization symbol. A product of the two correlations results in a magnitude peak and a phase difference. The magnitude peak is used to determine the location in time of the sync symbol and the phase difference is used to determine the frequency offset of the received signal.