Harris Corporation

Harris Global Communications, Inc.

Clifford Hessel

Paul Edward Voglewede

James Anthony Norris

Christopher David Mackey

Michael E Kreeger

Nick Andrew Van Stralen

John E Gorton

Prabodh Varshney

Scott Ensign Marks

Louis M Orsini

Alfred W Pietzold, Iii

William Nelson Furman

David M Smith

Dennis Michael Martinez

Fred C Kellerman

Richard Booton

Richard J Buckley

Richard James Buckley

Dennis Martinez

Thomas Gerard Kenney

James J Hood

Gerald Saeva

Douglas C Crawford

Kenneth Arndt

Kenneth Symons

Nick A Van Stralen

A method to facilitate late entry of a late entrant node into an ad-hoc radio network involves accessing from a memory at the late entrant node an initial frequency hopping sequence for the ad-hoc radio network. The late entrant node uses at least the initial frequency hopping sequence to determine a first frequency to monitor during a communication epoch corresponding to one of the frequency hops. The late entrant node thereafter monitors the first frequency to detect the presence of a beacon signal transmitted by a participating node of the network. Subsequently, the late entrant node determines a second frequency included in the current hopping sequence of the network based on information contained in the beacon signal.

Method to bootstrap into a frequency agile ad hoc network of radios that use a non-deterministic frequency pattern

A method for detecting a presence of an RF signal begins by forming with at least one computer processor a sample correlation matrix A from a sample of a radio frequency channel. Thereafter, the at least one computer processor determines a trace tr(A) of the sample correlation matrix and a determinant det(A) of the sample correlation matrix. The at least one processor then selectively determines a presence or absence of a signal on the radio frequency channel based exclusively on the trace, the determinant and a threshold value T. The invention also includes a cognitive radio which includes a radio receiver configured to detect an RF signal and at least one computer processing device for performing the above-described method.

Simplified blind signal detector

Dynamic spectral assignment in an ad hoc network of wireless network nodes () includes determining () a set of allowed frequencies that can be used by the ad hoc network and a corresponding index value for each of the allowed frequencies. An allowed list is created () and comprised of the index values () arranged in a deterministic order. A pointer () into the allowed list () is determined for each one of a total of Nhop frequency hops of a hopping sequence. Each pointer specifies one of the allowed frequencies () to be used for a corresponding one of the frequency hops. A wireless frequency hopping communication session is performed among a plurality of the nodes in the ad hoc network, using a frequency for each hop of the hopping sequence as specified by the pointers ().

Specification of a frequency agile dynamic spectrum access TDMA method

A communication network may be uncooperative with an uncooperative communications device. The communication network includes mobile wireless communications devices including a collection device and forward devices. Each forward device is configured to detect a received signal characteristic associated with the uncooperative communications device, and transmit the received signal characteristic to the collection device. The collection device is configured to selectively schedule reception of the received signal characteristic based upon a timing of communications among the forward devices, and determine a parameter associated with the uncooperative communications device based upon the received signal characteristic.

Communication network for detecting uncooperative communications device and related methods

System and method for determining an optimal transmission center frequency for a traffic station () in a satellite communication system () includes transmitting, by the traffic station () in a first uplink channel, a first burst of information in a first uplink TDMA frame to a satellite () and receiving, by the traffic station () in a first downlink channel, a downlink TDMA frame including a reference burst () and the first burst of information. A Doppler offset ratio is calculated based on a measured frequency shift of the received first burst of information. A local oscillator offset ratio is calculated based on a measured frequency shift of the reference burst and the Doppler offset ratio. An adjusted transmission frequency of a second uplink channel is calculated based on the Doppler offset ratio and the local oscillator offset ratio.

System and method of doppler and local oscillator compensation in a TDMA system

A system and method is disclosed for maintaining synchronization in a communication system in which a signal is sent from a transmitter to a receiver which includes a phase lock loop. The receiver compares the output of a Viterbi decoder with the output of a quick decision circuit. The Viterbi decoder, which incorporates traceback, determines the minimum aggregate Euclidean distance for multiple symbols. The quick decision circuit determines the minimum Euclidean distance for a single symbol without decoding the symbol. If the difference in the output signals of the Viterbi decoder and the quick decision circuit is greater than a predetermined threshold, the phase error signal in the phase lock loop is prevented from updating the phase lock loop filter. A synchronization loss detector may also be used to prevent the phase error signal from updating the phase lock loop filter if synchronization loss is detected.

Phase lock loop and method for coded waveforms

A removable, wireless, cryptographic ignition key (CIK) provides a user the capability to conduct secure operations utilizing a processor as long as the CIK is within the vicinity of the processor. This removable CIK may be utilized in applications related to conducting secure operations on desktop computers, laptop computers, wireless telephones, handheld radios (e.g., military radios requiring secure communications), and personal digital assistants (PDAs). Secure operations are enabled upon insertion and removal of the CIK into/from the processor. If a predetermined proximity between the removable CIK and the processor is exceeded (e.g., the user leaves the room, the user puts the processor on a moving belt on an X-ray machine at the airport, the processor is stolen), secure operations are disabled. Secure operations may be resumed, upon the CIK being inserted and removed into/from the processor again.

Removable cryptographic ignition key system and method

A time division multiple access (TDMA) waveform for controlling a MIL-STD-188-183 compliant demand assignment multiple access (DAMA) satellite communication network contains a short duration and minimal data content, time-hack, that is repeatedly transmitted by a supervisory control radio, so that the time hack occurs twice within a DAMA frame, ensuring that every radio can acquire frame synchronization, irrespective of overlap in receipt of one of the time-hacks with a voice/data channel transmission by that radio. The time-hack also identifies which one among a list of different frame formats stored in the radio is to be employed.

Timeslot assignment mechanism for satellite communication network

A system and method for implementing a wireless communications link between two equipment envelopes through inductive coupling include two 'U' shaped inductors. Wireless communications is achieved via mutual inductance between the two inductors. Circuitry is provided, which enables the transmitter to determine if a receiver is within communications range. When the two envelopes are aligned, a dual-gap toroidal core is formed, in which the gaps have opposite polarity. The opposing polarity of the two gaps minimizes the far field signature of the transmitter/receiver pair, thus enhancing communication security.

System and method for secure wireless connection

The present invention relates generally to communication systems, both wired and wireless, employing a continuous phase modulation ('CPM') waveform with a minimum shift keying ('MSK') preamble. The present inventive system and method uses information from contiguous Fourier Transforms taken on contiguous data blocks to determine baud rate, phase, frequency offset, and bit timing of the CPM waveform or can be used to determine the frequency of continuous wave waveform. More particularly, the inventive system and method is applicable to the military satellite communications UHF frequency band for deciding whether a signal of interest is.

System and method for obtaining accurate symbol rate and carrier phase, frequency, and timing acquisition for minimum shift keyed waveform

A system and method is herein described for the wide band acquisition of a high performance waveform in an environment with poor signal to noise ratio. The waveform acquired has a preamble with a plurality of frequency modulated Maximum Length Sequences and a period of pure carrier. In one embodiment, method provides an application specific integrated circuit (ASIC) for receiving the waveform, filter coefficients for use with the MLS's portion of the waveform, and filter coefficients for the pure carrier portion of the signal. Another embodiment may also include, for the MLS portion of the signal, detecting the signal through partial correlation, extracting waveform information, and estimating symbol timing. Yet another embodiment may further include, for the pure carrier portion of the signal, estimating the phase and frequency of the signal and providing those estimates to an ASIC.

System and method for enhanced acquisition for large frequency offsets and poor signal to noise ratio

A radio system demodulates a continuous phase modulation waveform with a pulse count demodulator. The use of a pulse count demodulator reduces the receiver complexity and reduces power consumption, which makes such a system well suited for hand held or mobile units. The pulse count demodulator delays the CPM signal by a time increment t, and subtracts the delayed signal from the original signal creating a difference signal. The difference signal is rectified and low pass filtered resulting in an average signal representing the phase change. In non-square wave CPM signals, the signal is first clipped removing the amplitude information.

System and method of low power demodulation of continuous phase modulated waveforms

A system and method of automatic gain control (AGC) processing of digital signals using Block AGC to acquire the signal and sample-by-sample AGC to track the signal.

Automatic gain control for digital signals

A communication system from maintaining synchronization includes a communication signal comprising a carrier and a data signal that is sent from a transmitter to a receiver which includes a phase lock loop. The receiver compares the output of a Viterbi decoder with the output of a quick decision circuit. The Viterbi decoder, which incorporates traceback, determines the minimum aggregate Euclidean distance for multiple symbols. The quick decision circuit determines the minimum Euclidean distance for a single symbol without decoding the symbol. A delay circuit is placed in series with the quick decision circuit to compensate for the traceback delay in the Viterbi decoder. If the difference in the output signals of Viterbi decoder and the quick decision circuit is greater than a predetermined threshold, the phase error signal in the phase lock loop is prevented from updating the phase lock loop filter. A synchronization loss detector may also be used to prevent the phase error signal from updating the phase lock loop filter if synchronization loss is detected.

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Rochester, NY, United States of America

Clifford Hessel