L-3 Communications Corporation

L3harris Technologies, Inc.

L3 Technologies, Inc.

Jeffrey B Bench

Sy Prestwich

Brent A Kenney

Brian J Thorp

Richard Alan McNamee

Matthew J Reimann

Rhett B McCarthy

Thomas R Giallorenzi

Dan M Griffin

Radivoje Zarubica

David G Landon

Philip M Hirz

Scott M Lyon

Patrick L Newbold

Anthony D Smith

Michael C Hollenbeck

Edwin R Twitchell

Stephen A Laraway

Lee F Carter

James E Hawker

Scott A Carey

Phillip Hunt

Michael B Hollenbeck

Marley D Hamblin

Brian L Thorp

Rhett B Mccarthy

Radijove Zarubica

Bryan J Thorp

Selecting a control channel set in a communication system involves monitoring received signals to identify a plurality of nodes of interest (NOI) and determining E/Nvalues for a plurality of control channels. For this purpose, a data metric and spectral data can be provided to the communication device by the respective NOI for which E/Nvalues are being determined. A comparison is made of the E/Nvalues for all NOI to select an optimal control channel set. The optimal control channel set is then used by the communication device to transmit the control channel information to the plurality of NOI.

Control channel diversity selection

A transmitter in a frequency domain duplexing (FDD) network system is configured to receive spectral information from neighbor receiver nodes. For each of the neighbor receiver nodes, the transmitter computes an SNR at each of the plurality of frequencies, forming an SNR curve. For each of the transmit frequencies, the transmitter identifies minimum SNR values among the SNR values on the SNR curves. The minimum SNR values form a composite minimum curve. Based on the composite minimum curve, the transmitter determines whether an SNR of a current transmit frequency is above (1) a first threshold associated with an operating SNR, or (2) a second threshold associated with a maximum of the composite minimum curve. Based on the determination, the transmitter determines whether a new transmit frequency is selected to replace the current transmit frequency.

Frequency selection in a frequency domain duplexing network

Systems and methods for evaluating link performance over a multitude of frequencies for Signal-to-Noise Ratio (SNR) optimization and mitigating interference. The methods comprise: communicating, from a first communication device, a first signal over a given channel in a given frequency band; receiving, by the first communication device, spectral power measurements and a Signal-to-Total Power Ratio (STPR) estimate determined based on a second signal including the first signal combined with at least one of noise and one or more interference signals (the STPR estimate accounts for the receiver performance including chip rate processing gain and/or the performance of an interference cancellation circuit used to remove the interference signals from the second signal); and determining, by the first communication device, a predicted Signal-to-Noise Ratio (SNR) condition for a plurality of frequencies within the given frequency band using the STPR estimate and the spectral power measurements.

Systems and methods for decentralized link performance

A communications system may include mobile communications nodes operating according to a current topology and reconfigurable to a new topology. Each mobile communications node may include a wireless transceiver, and a controller configured to transmit spectral performance data to adjacent nodes and receive spectral performance data from the adjacent nodes. The controller may identify potential topologies for the adjacent nodes based on the spectral performance data, select a subset of potential topologies from among the potential topologies, generate a respective performance score for each potential topology of the subset of potential topologies, and switch to a new topology from among the subset of potential topologies based upon the performance scores.

Communications system reconfigurable to different topologies and associated methods

Providing signal-to-noise ratio information to a local transmitter node. A method includes receiving data in a signal transmitted on a data channel from the local transmitter node. A first signal-to-total-power ratio for the signal assuming no jamming of the signal is occurring is computed. A second signal-to-total-power ratio for the signal with factors included assuming jamming is occurring is computed. The first signal-to-total-power ratio to the second signal-to-total-power ratio are compared to determine if they differ by a predetermined amount. The method includes determining that the predetermined amount is exceeded, and as a result, a jammed signal-to-noise ratio is computed assuming jamming is occurring. The jammed signal-to-noise ratio is sent to the local transmitter node to allow the local transmitter to respond to the jammed signal-to-noise ratio.

Abrupt interference mitigation

Joining subnets in mobile ad-hoc network (MANET) environment. A method includes, based on SNR, power and data rate information between a first gateway node for a first subnet and a second gateway node for a second subnet, determining a rate at which the first and the second subnets can connect if nodes in the first subnet reduce signal transmit rate to a predetermined level. The method further includes as a result of determining that the determined rate meets or exceeds a predetermined threshold, then joining the first and second subnets by joining the first and second subnets via the first and second gateway nodes and causing nodes in the first subnet to reduce signal transmit rate to the predetermined level.

Gateway link management between disjoint subnetworks in a CDMA MANET

A mainlobe detection process can include a number of tests that are performed to define when the monopulse antenna system will transition from open loop scanning to closed loop scanning and then to tracking. A hybrid tracking technique is also provided which adaptively discovers and corrects for phase alignment error. Magnitude-only tracking can be performed initially to locate the nulls in the azimuth and elevation ratios and to identify the magnitudes of these ratios at these nulls. Phase tracking can be then performed. During phase tracking, phase corrections can be repeatedly applied to the azimuth and elevation difference channels to correct any phase error that may exist. During this process, the magnitudes of the ratios can be used to determine how the phase corrections should be adjusted. Once the hybrid tracking process is complete, the monopulse antenna system is properly phase-aligned and phase tracking will be correctly employed.

Adaptive discovery and correction of phase alignment errors in monopulse antenna systems

A monopulse antenna system can include a monopulse detector assembly (MDA) that is configured to steer a monopulse antenna based on the magnitude of an elevation ratio or azimuth ratio independently of the phase of the ratio. To prevent the direction of the monopulse antenna from being changed too frequently, the MDA can employ ratio bins to determine when the direction of the monopulse antenna should be reversed. Also, the MDA may enforce a hold period during which a change in the direction of the monopulse antenna will not be performed. The MDA can employ one or more mapping equations to generate a steering signal as a function of the magnitude of the ratio. The mapping equations can be selectively employed based on whether tracking is being performed at or near the ratio null.

Phase agnostic monopulse tracking

A monopulse tracker includes multiple dual-axis monopulse antenna systems that are angled with respect to one another. The orientations of the monopulse antenna systems create a much larger field of view for the monopulse tracker to eliminate the need to steer the monopulse tracker. The monopulse tracker can be configured to estimate a position of an object based on tracking information received from more than one monopulse antenna system therefore increasing the accuracy of the estimated position. The multiple monopulse antenna systems can be arranged in a low-profile housing to facilitate use of the monopulse tracker on aircraft.

Low-profile monopulse tracker

Mainlobe detection process for monopulse antenna systems

Systems and method for detecting and removing an arbitrary phase difference between a sum channel signal and a difference channel signal in a monopulse system. A sum channel signal is received from a sum channel signal source and a difference channel signal is received from a difference channel signal source. The difference channel signal is shifted according to various potential arbitrary phase differences &#x3c6;and &#x3c6;+&#x3c0; (where &#x3c6;is from 0 to &#x3c0; radians, i=0, 1, . . . , n; &#x3c6;+&#x3c0; going from &#x3c0; to 2&#x3c0; radians) between the sum and difference channel signals to thereby generate difference channel signals each having a different phase. The difference channels having a different phase are combined with the sum channel signal to generate a plurality of sum+difference signals and sum&#x2212;difference signals. Based on the plurality of sum+difference signals and sum&#x2212;difference signals, maximum in-phase and out-of-phase correlations are determined from the &#x3c6;and &#x3c6;+&#x3c0; pairs. The maximum in-phase and out-of-phase correlation pairs are used in an error estimate calculation.

Monopulse arbitrary phase detection and removal

A digital communications receiver can comprise a digital filter that can be configured and later reconfigured multiple times as, for example, a matched filter, an equalizer, a matched filter and equalizer, or the like. For example, the digital filter can be initially configured as a matched filter for use with a correlation module to detect pilot symbols. Detected pilot symbols can be utilized to estimate characteristics of a channel from the distant transmitter to the receiver, and the estimated channel characteristics can be used to determine coefficients for an equalizer for reducing channel distortion in future transmissions received over the channel. The digital filter can then be configured as an equalizer or a matched filter and equalizer. If the later, the digital filter can both equalize incoming transmissions from the distant transmitter and, with a correlation module, identify any pilot symbols in the transmissions. Any detected pilot symbols can be utilized to determine again equalizer coefficients for equalizing transmissions received over the channel, and the digital filter can be updated accordingly.

Growing community of inventors

Lehi, UT, United States of America

Jeffrey B Bench