Abstract: Devices, systems, and methods for software-defined cognitive networking for wireless communications are provided. An example method of wireless communication includes performing, at a first node of a plurality of nodes, multiple network interference measurements to generate a first local interference model, receiving, from a second node of the plurality of nodes, a second local interference model, combining, at the first node, the first local interference model and the second local interference model to generate a joint interference model, generating, based on the joint interference model, a plurality of interference parameters that characterize a communication channel between the first node and the second node, selecting, based on the plurality of interference parameters, an operating waveform from a plurality of waveforms such that a performance metric for a data communication from the first node to the second node exceeds a threshold, and performing, using the operating waveform, the data communication.

Abstract: Devices, systems and methods for providing network-enabled connectivity for disadvantaged communication links in wireless networks are described. One example method for enabling connectivity over a disadvantaged link includes receiving, by a first node of a plurality of nodes from a source node in the first frequency band in a first timeslot, a first signal comprising a message, receiving, by the first node from at least a second node in a second frequency band in a second timeslot, a second signal that is used to generate a first reliability metric corresponding to the message, and performing, based on a plurality of reliability metrics corresponding to the message and the first reliability metric, a processing operation on the message, the first frequency band being non-overlapping with the second frequency band, and a duration of the first timeslot being greater than a duration of the second timeslot.

Abstract: Methods, devices and systems that use a control channel to coordinate quality of data communications in software-defined heterogenous multi-hop ad hoc networks are described. In some embodiments, an example apparatus for wireless communication in a network includes performing, using a control plane, network management functions over a control channel that has a first bandwidth, implements a frequency-hopping operation, and operates at in a first frequency band, and performing, using a data plane that is physically and logically decoupled from the control plane, data forwarding functions, based on a routing decision, over at least one data channel that has a second bandwidth and operates in a second frequency band different from the first frequency band.

Abstract: Devices, systems and methods for high-utilization low-latency multi-channel time-division multiplexing access (TDMA) are described. One example method for wireless communication includes performing, in a first time interval of a time-division multiple access (TDMA) slot, a transmission of a first data unit over a first logical channel of the plurality of logical channels, refraining from transmitting, subsequent to a completion of the transmission of the first data unit, for a second time interval immediately after the first time interval, and performing (N?1) transmissions in (N?1) time intervals for each data unit of (N?1) subsequent data units in the TDMA slot, such that a transmission of an nth data unit of the (N?1) subsequent data units is performed over an nth logical channel of the plurality of logical channels.

Abstract: Devices, systems and methods for providing network-enabled connectivity for disadvantaged communication links in wireless networks are described. One example method for enabling connectivity over a disadvantaged link includes receiving, by a first node of a plurality of nodes from a source node in the first frequency band in a first timeslot, a first signal comprising a message, receiving, by the first node from at least a second node in a second frequency band in a second timeslot, a second signal that is used to generate a first reliability metric corresponding to the message, and performing, based on a plurality of reliability metrics corresponding to the message and the first reliability metric, a processing operation on the message, the first frequency band being non-overlapping with the second frequency band, and a duration of the first timeslot being greater than a duration of the second timeslot.

Abstract: Devices, systems and methods for analog automatic gain control (AGC) based on estimated distributions of signal characteristics are described. One example method includes generating a digital measurement of a first signal characteristic based on a second signal characteristic of an input signal received by the device, where the second signal characteristic is based on a level of the input signal. The digital measurement of the signal characteristic is used to update a statistical model for the input signal and the posterior probability distribution of the second signal characteristic conditioned on previous digital measurements of the first signal characteristic. The updated posterior probability distribution is used to generate a gain estimate, which is then used to adjust the power level of the input signal. Another example method may use multiple statistical models for each waveform supported by the system.

Abstract: Methods and systems for estimating and mitigating OFDM interference to enable reliable communications with minimal a priori knowledge of the interfering OFDM signal are presented. Embodiments of the present invention hypothesize modulation symbols from a reference signal set, which may not be identical to the interference signal set, and compute a channel sequence to minimize an error between the observed samples and a product of the channel sequence and the hypothesized modulation symbols. The interfering OFDM signal may be estimated and mitigated with no reliance on knowledge of the interference signal set, although this may result in the inability to decode and demodulate the interfering OFDM signal when embodiments of the present invention are extended from single-input single-output systems to multiple-input single-output systems.

Abstract: Secure and efficient methods and systems of providing multiple access interference constraints for frequency hopped spread spectrum communications are presented. The methods and systems leverage a cryptographic keystream generator and iterative indexing into shuffled lists to generate a constrained collision-free frequency hopping sequence. This flexible frequency hopping access (FFHA) can support varying hop frequency and bandwidth resources including secure operation for applications where the number of channels (hopping sequences) exceeds the number of hop frequency resources available.

Abstract: The estimation and mitigation of swept-tone interferers includes receiving a composite signal comprising a signal of interest and a swept-tone interferer over an observation bandwidth or a hop bandwidth in a frequency-hopping system. The estimation of the interfering signal may be based on modeling the interferer as a magnitude periodic signal comprising non-overlapping, contiguous epochs, where each epoch may comprise a common pulse shape and a distinct phase rotation. The modeling may be based over the observation bandwidth, the hop bandwidth, or after combining the signal over all the frequency hop bandwidths. The period of the magnitude-periodic signal may be initially determined, and the common pulse shape and each of the distinct phase rotations may then be estimated. These estimates may be used to reconstruct an estimate of the swept-tone interferer, which may be subtracted from the composite signal to generate an interference-mitigated signal of interest.

Abstract: Throughput for rate-adaptive wireless communication is maximized by accounting for the rate loss associated with selecting a transmission rate as a function of the actual rate supported by the channel. An optimal rate is selected by minimizing a set of average cost functions; each of the average cost functions is based on the delayed LQMs and rate-loss cost functions associated with selecting a candidate transmission rate as a function of a maximum rate supported by the channel.

Abstract: Systems and methods are presented for topology discovery in a multi-hop ad hoc network. The method operates on two time and distance scales. Nodes periodically transmit messages to their immediate neighbors that enable the discovery of their two-hop network topologies (i.e., within two hops). Less frequently, nodes broadcast messages network-wide that enable the discovery of the global network topology at all nodes. In multi-hop ad hoc network architectures that are characterized by efficient broadcast protocols—e.g., Barrage Relay Networks—the proposed method provides a particularly efficacious means for global topology discovery.

Abstract: The estimation and mitigation of swept-tone interferers includes receiving a composite signal comprising a signal of interest and a swept-tone interferer over an observation bandwidth. The estimation of the interfering signal may be based on modeling the interferer over the observation bandwidth as a magnitude periodic signal comprising non-overlapping, contiguous epochs, where each epoch may comprise a common pulse shape and a distinct phase rotation. The period of the magnitude-periodic signal may be initially determined, and the common pulse shape and each of the distinct phase rotations may then be estimated. These estimates may be used to reconstruct an estimate of the swept-tone interferer, which may be subtracted from the composite signal to generate an interference-mitigated signal of interest.

Abstract: A method for interference estimation and mitigation includes receiving a high-resolution digital signal. The high-resolution digital signal comprises a signal of interest and an interfering signal. An estimate of the interfering signal is generated using a quantizer. The signal of interest is in a quantization noise of the quantizer. An interference-mitigated signal of interest is generated based on a difference of the estimate of the interfering signal and the high-resolution digital signal.

Abstract: A method and system for flexible radio communications using a wideband radio includes a wideband radio and multiple separable radio definition modules, wherein the wideband radio is configured to operate over a large portion of the radio-frequency (RF) spectrum and each of the radio definition modules are configured to operate in a specific frequency band. The separability of the radio definition modules maintains the capability of the wideband radio to operate over the large portion of the RF spectrum, as well as enabling its robust and reliable operation in a specific frequency band associated with the attached radio definition module.

Abstract: An apparatus for joint analog and digital interference cancellation includes a receiver configured to receive an analog reference interfering signal on a reference path, and a sum of an analog interference signal and an analog signal of interest on an antenna path. An analog interference canceller may be configured to produce an analog partially interference-cancelled signal using the analog reference interfering signal and the sum of the analog interference signal and the analog signal of interest. A first analog-to-digital converter may be configured to digitize the analog reference interfering signal to produce a digital reference interfering signal. A second analog-to-digital converter may be configured to digitize the analog partially interference-cancelled signal to produce a digital partially interference-cancelled signal.

Abstract: Systems and methods are presented for controlling the peak-to-average-power of a baseband orthogonal-frequency-domain multiplexing (OFDM) signal by designating a subset of the available subcarriers as information-bearing data-subcarriers, and loading remaining subcarriers by symbols that are a function of the symbols loading the data-subcarriers. At the receiver, the data-dependent subcarriers are optionally combined with data-subcarriers to increase error protection.

Abstract: An apparatus for joint analog and digital interference cancellation includes a receiver configured to receive an analog reference interfering signal on a reference path, and a sum of an analog interference signal and an analog signal of interest on an antenna path. An analog interference canceller may be configured to produce an analog partially interference-cancelled signal using the analog reference interfering signal and the sum of the analog interference signal and the analog signal of interest. A first analog-to-digital converter may be configured to digitize the analog reference interfering signal to produce a digital reference interfering signal. A second analog-to-digital converter may be configured to digitize the analog partially interference-cancelled signal to produce a digital partially interference-cancelled signal.

Abstract: A method for secure key agreement among a subset of a plurality of transceivers includes generating a first ordered subset of a plurality of keys k?j, where j=0 to S. Each of the subset of the plurality of transceivers may possess at least one of the plurality of keys k?j from the first ordered subset. Each of the subset of the plurality of transceivers possessing one or more keys k?i, i=1 to S, also possesses at least one key from a second ordered subset of the plurality of keys k?j, j=0 to i?1. A key with index ?0 is designated as a group key. A binary sum of the group key k?0 and a key k?j, where j?0, is transmitted from one or more of the subset of the plurality of transceivers that possesses the group key k?0.

Abstract: Systems and methods are presented for establishing network-wide time synchronization in a time-slotted barrage relay network. In the first phase, nodes obtain coarse, slot-level time synchronization by estimating the time-of-arrival (TOA) of a message that rapidly floods the network via the barrage relay mechanism. In the second phase, fine time synchronization is achieved via a messaging protocol that exchanges TOA information between neighboring nodes.

Abstract: A method for secure key agreement among a subset of a plurality of transceivers includes generating a first ordered subset of a plurality of keys k?j, where j=0 to S. Each of the subset of the plurality of transceivers may possess at least one of the plurality of keys k?j from the first ordered subset. Each of the subset of the plurality of transceivers possessing one or more keys k?i, i=1 to S, also possesses at least one key from a second ordered subset of the plurality of keys k?j, j=0 to i?1. A key with index ?0 is designated as a group key. A binary sum of the group key k?0 and a key k?j, where j?0, is transmitted from one or more of the subset of the plurality of transceivers that possesses the group key k?0.