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: 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 collaborative wireless communication in a wireless network are described. One example method includes performing, by a first node of a plurality of nodes, a communication with at least a second node of the plurality of nodes, receiving, by the first node from a destination node of the plurality of nodes, a probe, computing, based on the probe, a phase of a strongest tap of a channel estimate between the first node and the destination node, computing a phase correction based on the phase of the strongest tap and a phase difference between a first phase of the first node and a second phase of a reference node, wherein the phase difference is based on the communication, and transmitting, to the destination node, a message with the phase correction.

Abstract: Methods and systems for reliable broadcasting that use re-transmissions, in a multi-hop, time-slotted wireless network, is presented. The methods and systems evaluate the trade-off between power consumption and communication reliability, and are consequently able to provide increasing degrees of robustness for broadcasts in the wireless network. Embodiments of the present invention are able to incrementally use re-transmissions, therein trading-off battery life for an increased message completion rate or a lower packet error rate, for example, in order to reliably broadcast critical or high-priority message network-wide.

Abstract: Methods and systems for improving authenticated encryption in counter-based cipher systems are presented. Embodiments of the present invention provide secure and efficient means to achieve both the authenticity and privacy goals of authenticated encryption, and are compatible with most block cipher modes of operation, e.g. CBC, CFB and CTR, and most symmetric-key cryptographic functions, e.g. AES, DES and RC5. In particular, using block cipher encryption with data-dependent initialization vectors achieve the privacy goal and enable over-the-air transmissions to remain uncompromised, especially in scenarios that may result in the counter being reset in counter-based cipher systems.

Abstract: Methods and systems for improving communication using angle dithering are presented. Embodiments of the present invention provide increased throughput and robustness after link establishment by providing fast fading characteristics in environments dominated by slow fading. In particular, fast fading characteristics are induced by steering the transmitter and receiver antennas in optical and beyond line-of-sight troposcatter communication systems based on dither patterns. In non-line-of-sight (NLOS) communication systems, using coordinated dither patterns at the transmitter and receiver ensures that successive common scattering volumes become decorrelated, whereas in line-of-sight optical communication systems, the dither pattern is based on the tropospheric scintillation in free space traversed by the established link.

Abstract: Methods and systems for improving communication in a multi-hop, time-slotted wireless network are presented. Embodiments of the present invention are able re-use timeslots to locally transmit information to one-hop nodes, thereby utilizing the bandwidth more efficiently. Other embodiments are able to evaluate the trade-off between power consumption and communication reliability, and are consequently able to provide increasing degrees of robustness for broadcasts in the wireless network. That is, these latter embodiments are able to incrementally use re-transmissions, therein trading-off battery life for an increased message completion rate or a lower packet error rate, for example, in order to reliably broadcast critical or high-priority message network-wide.

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: A method and system for maximizing throughput and minimizing latency in a communication system that supports heterogeneous links is presented. The communication system supports a primary link and an alternate link, and the method and system leverage the alternate link to reduce the overhead transmitted over the primary link, thereby increasing throughput and reducing end-to-end latency. The higher latency alternate link provides a delayed version of an information signal that corresponds to a portion of the information signal that is transmitted on the primary link. The received samples from the primary and alternate links may be used to equalize subsequent portions of the information signal received over the primary link, and may also be used for synchronization, timing recovery, DC offset removal, I/Q imbalance compensation, and frequency-offset estimation.

Abstract: Methods and systems for reliable broadcasting that use re-transmissions, in a multi-hop, time-slotted wireless network, is presented. The methods and systems evaluate the trade-off between power consumption and communication reliability, and are consequently able to provide increasing degrees of robustness for broadcasts in the wireless network. Embodiments of the present invention are able to incrementally use re-transmissions, therein trading-off battery life for an increased message completion rate or a lower packet error rate, for example, in order to reliably broadcast critical or high-priority message network-wide.

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.