Massachusetts Institute of Technology

Bae Systems Information and Electronic Systems Integration Inc.

Collision Communications, Inc.

Rachel E Learned

Robert B MacLeod

Matthew A Taylor

Paul David Fiore

Nicholas J Kaminski

Matthew J Sherman

Brandon P Hombs

Karl D Brommer

Diane Grieselhuber Mills

Joshua D Niedzwiecki

Thomas P McElwain

Prabahan Basu

Joseph Su

In some embodiments, a method for mitigating interference in a channel having multiple users includes: transmitting, by a transmitter, a signal of interest (SOI) to a sequential interference cancellation (SIC) receiver at a transmit power; determining a packet drop rate as seen by the receiver; and decreasing the transmit power in response to determining the packet drop rate exceeds a predetermined maximum packet drop rate. The transmitter's coding rate and/or modulation level may also be lowered based on the decrease in transmit power.

Mitigation of communication signal interference using adaptive transmit power

In some embodiments, a method for mitigating interference in a channel having multiple users can include: determining a starting angle based on a direction of a signal of interest (SOI); iteratively steering a beam away from the starting angle in opposite directions and calculating a grade of the beam; choosing the beam at a current angle as a receive beam based on the beam grade; receiving a signal using the receive beam; and decoding the SOI from one or more interfering signals using successive interference cancellation multi-user detection (SIC MUD) on the received signal.

Method and apparatus for determining a receiver beam in a co-existence cognitive radio

In some embodiments, a method for mitigating interference in a channel having multiple users includes: receiving a plurality of signals from a plurality of antenna elements, the received signals comprised of one or more interfering signals and a signal of interest (SOI); for each of the one or more interfering signals, beamforming the received signals to enhance the interfering signal, generating an estimate of the interfering signal, and adjusting the estimated interfering signal to undo the effects of beamforming; and subtracting each of the estimated interfering signals from each of the received signals to generate a plurality of interference-mitigated received signals.

Multi-antenna sequential interference cancelling receiver

A receiver includes multi-user detection (MUD) functionality and a cognitive engine. The receiver may also be coupled to multiple antennas and have analog beamforming capability. The cognitive engine is operative for selecting a beam or beams associated with the multiple antennas to enable successful demodulation by the MUD. The receiver has application in multiple access channels and in other communication scenarios.

Method and apparatus for smart adaptive dynamic range multiuser detection radio receiver

In a radio network having a plurality of first users on channel (FUOCs) and one or more second users on channel (SUOCs), a method and apparatus for a SUOC to select a channel to co-occupy based upon a 'selfish' goal of achieving a desired SUOC rate and an 'altruistic' goal of causing low-impact on the FUOC. A SUOC collects signal parameters for a plurality of FUOCs, orders the FUOCs based upon different criteria, and attempts to co-exist with FUOCs until a suitable FUOC channel is found.

Cognitive radio method and apparatus for achieving ad hoc interference multiple access wireless communication

A cognitive coexistence radio utilizes message fractionation and physical layer channel assignment to achieve co-existence communications in the presence of interferers. A transmit signal is split into a plurality of streams for transmission in occupied channels according to power allocation and modulation scheme. A near-optimal selfish power allocation scheme is based on the water-filling solution. A receiver can receive and decode the streams using parallel MUDs.

Message fractionation and physical layer channel assignment for multiuser detection-enabled wireless communication among adaptive interference

An SUOC radio employs: (1) Spectrum sensing and parameter estimation methods to characterize potential FUOCs; (2) A rate pair prediction tool to guide it's choice of FUOC to target along with the appropriate rate pair (SUOC and FUOC achievable rates); (3) Machine learning methods to automatically and on the fly advantage experience/history; (4) A decision maker with multiple possible procedures that govern steps of interaction; (5) Multiuser detection receiver to deal with the interference once information-bearing transmission has commenced by the SUOC radios. (6) a radio capable of full transmit-processing chain to accomplish modulation and full receive-processing chain to accomplish demodulation, as well as other radio functions necessary for successful wireless communications such as medium access control, networking and other functions.

In a radio network having a plurality of first users on channel (FUOCs) and one or more second users on channel (SUOCs), a method and apparatus for a SUOC to select a channel to co-occupy based in part upon the expected impact on the FUOC. The FUOC collects signal parameters associated with the FUOC, such as actual rate, bandwidth, received signal power, and noise power, and uses the signal parameters to calculate the expected impact. In some embodiments, the expected impact is proportional to the ratio of the FUOC's actual rate and the FUOC's possible code rate.

Techniques are described for determining rates and other parameters for users associated with a multiple access channel (MAC). In at least one embodiment, a rate determination tool having a GUI interface is provided.

Method and apparatus for rate determination in a radio frequency system

A method and apparatus for transmitting and receiving in black space is described. The asymmetric interference channel is an appropriate model for many realistic scenarios, especially those arising more frequently as dynamic spectrum access (DSA) becomes more prevalent. As DSA nodes evolve to become more cognitive (e.g. self aware, environment aware, and adaptive), the prevailing white space seeking and gray space adapting policies leave a significant portion of the spectrum, namely, the black space, untapped. Described herein is a throughput versus SINR result and a corresponding technique for jointly choosing a transmission rate and multiuser detection algorithm that allows computationally constrained cognitive DSA nodes high rate operation in spectrum black space. Also described is an information theoretic motivated policy for seemingly insignificant waveform design choices that greatly enhance the throughput of a secondary sender-receiver pair while fulfilling a given complexity requirement within the secondary node's receiver.

Method and apparatus for making optimal use of an asymmetric interference channel in wireless communication systems

A tactical radio includes a radio frequency (RF) processing module having a receiving component path and a transmitting component path. A signal processing module coupled to the RF processing module includes a jammer detection stage for identifying a type of jamming signal on a channel over which communications signals are received simultaneously. A jammer model stage in the signal processing module produces a waveform model for the jamming signal, and a channel model stage replicates propagation conditions on the channel and produces a corresponding cancellation signal. The cancellation signal is coupled at such a level into the receiving component path so as to cancel the jamming signal from received communications signals at the front end of the radio. Any residual jamming signals may then be removed by a secondary jamming cancellation stage operating at baseband.

Tactical radio and radio network with electronic countermeasures

A digital wireless communication system for increasing the number of users capable of communicating over a network permits multiusers to transmit information simultaneously on the same channel of frequency. The primary example of such a system would be that employing radio frequency transmissions, even optical transmissions; however, the invention will also apply to magnectic detections such as in the reading of information stored on a magnetic tape. It is possible to increase overall throughput in terms of total number of bits transmitted through the shared medium by all users of a multiple access system if the signals are allowed to interfere. The present invention provides a multiuser detection process and apparatus that is capable of pulling apart signals in heavy interference in real time by combining the signals received from two or more spatially seperated collectors or antennas. The present invention includes the step of taking more measurements of the received signal from two separate collections prior to definition of the multiuser algorithm parameters and combining the different collection of signals as one signal for multiple user detection processing.

Receiver with multiple collectors in a multiple user detection system

A Tree-structured multicarrier multiple access communication system in a multiple access environment having a number of interfering signals. In one embodiment an environment estimator estimates and tracks the number of interfering signals of the environment. A code selector determines an optimal spreading code represented by the environment, and identifies an actual spreading code that is closest to the optimal spreading code. A signal transmitter can then be used to transmit a multicarrier multiple access signals in accordance with the actual spreading code identified. On the receiver side, a multiuser detector (MUD) module performs tree structured multiuser detection signal processing, and produces a bit stream for each interfering signal.

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Waltham, MA, United States of America

Rachel E Learned